JP6111317B2 - Semiconductor device manufacturing method, substrate processing method, substrate processing apparatus, program, and recording medium - Google Patents

Description

  The present invention relates to a semiconductor device manufacturing method, a substrate processing apparatus, a substrate processing system, and a program.

  As a process of manufacturing the semiconductor device, a process of forming a thin film such as a silicon oxide film on the substrate by supplying a source gas containing a predetermined element such as silicon or an oxidizing gas to the substrate is performed. There is. At that time, for example, by using a catalyst gas, it is possible to form a film at a relatively low temperature, and it is possible to improve a thermal history received by the semiconductor device.

  When forming a thin film on a substrate, for example, carbon may be included in the thin film to improve the resistance to wet etching and to improve the film quality, for example, to reduce the dielectric constant of the film.

  However, under relatively low temperature conditions, a sufficient amount of carbon may not be taken into the film or impurities such as moisture may be mixed into the film. For this reason, the subject that the thin film of a low dielectric constant provided with sufficient etching tolerance cannot be formed will arise, for example.

  An object of the present invention is to provide a technique for forming a low dielectric constant thin film having excellent etching resistance.

According to one aspect of the invention,
Forming a thin film on the substrate;
Removing the first impurities including moisture and chlorine from the thin film by heat-treating the thin film at a first temperature higher than the temperature of the substrate in the step of forming the thin film;
Removing the second impurity containing a hydrocarbon compound from the thin film after the heat treatment at the first temperature by heat-treating the thin film at a second temperature equal to or higher than the first temperature;
A method of manufacturing a semiconductor device having the above is provided.

According to another aspect of the invention,
A processing chamber for accommodating the substrate;
A processing gas supply system for supplying a processing gas for forming a thin film into the processing chamber;
A heater for heating the substrate in the processing chamber;
The process gas is supplied to the substrate in the processing chamber to form a thin film on the substrate, and the thin film is heat-treated at a first temperature higher than the temperature of the substrate in the process of forming the thin film. Thus, heat treatment is performed at the first temperature by removing the first impurities including moisture and chlorine from the thin film and heat-treating the thin film at a second temperature equal to or higher than the first temperature. A controller configured to control the processing gas supply system and the heater so as to perform a process of removing a second impurity including a hydrocarbon compound from the later thin film;
A substrate processing apparatus is provided.

According to yet another aspect of the invention,
A first substrate processing unit for forming a thin film on the substrate; a second substrate processing unit for heat-treating the thin film;
A substrate processing system comprising:
The first substrate processing unit includes:
A first processing chamber for accommodating a substrate;
A processing gas supply system for supplying a processing gas for forming a thin film into the first processing chamber;
A first control unit configured to control the process gas supply system so as to perform a process of supplying the process gas to the substrate in the first process chamber to form a thin film on the substrate; Have
The second substrate processing unit includes:
A second processing chamber for accommodating a substrate;
A heater for heating the substrate in the second processing chamber;
By heat-treating the thin film at a first temperature higher than the temperature of the substrate in the process of forming the thin film in a state where the substrate on which the thin film is formed is accommodated in the second processing chamber, From the thin film after heat treatment at the first temperature by removing the first impurities including moisture and chlorine from the heat treatment and heat treating the thin film at a second temperature equal to or higher than the first temperature. There is provided a substrate processing system having a second control unit configured to control the heater so as to perform a process of removing a second impurity including a hydrocarbon compound.

According to yet another aspect of the invention,
A procedure for forming a thin film on a substrate in a processing chamber;
Removing the first impurities including moisture and chlorine from the thin film by heat-treating the thin film at a first temperature higher than the temperature of the substrate in the step of forming the thin film;
Removing a second impurity containing a hydrocarbon compound from the thin film after the heat treatment at the first temperature by heat-treating the thin film at a second temperature equal to or higher than the first temperature;
A program for causing a computer to execute is provided.

  According to the present invention, it is possible to form a low dielectric constant thin film having excellent etching resistance.

It is a schematic block diagram of the vertical processing furnace of the substrate processing apparatus used suitably by 1st Embodiment of this invention, and is a figure which shows a processing furnace part with a longitudinal cross-sectional view. It is a schematic block diagram of the vertical processing furnace of the substrate processing apparatus used suitably by 1st Embodiment of this invention, and is a figure which shows a processing furnace part with the sectional view on the AA line of FIG. It is a schematic block diagram of the controller of the substrate processing apparatus used suitably by 1st Embodiment of this invention, and is a figure which shows the control system of a controller with a block diagram. It is a figure which shows the timing of the gas supply in the film-forming sequence of 1st Embodiment of this invention and its modification, (a) is a figure which shows the sequence example of 1st Embodiment, (b) is a figure of a modification. It is a figure which shows the example of a sequence. It is explanatory drawing of the catalytic reaction of the thin film formation process of 1st Embodiment of this invention, Comprising: (a) is a figure which shows the catalytic reaction in step 1a, (b) is a figure which shows the catalytic reaction in step 2a. . It is a figure which shows the timing of the gas supply in the film-forming sequence of 2nd Embodiment of this invention and its modification, (a) is a figure which shows the example of a sequence of 2nd Embodiment, (b) is Modification 1 FIG. 10C is a diagram illustrating a sequence example of Modification 2. It is a figure which shows the timing of the gas supply in the film-forming sequence of 3rd Embodiment of this invention, (a) is a figure which shows the example of a sequence which forms a stack film, (b) is the example of a sequence which forms a laminated film FIG. It is a figure which shows the timing of the gas supply and RF electric power supply in the film-forming sequence of the modification of 3rd Embodiment of this invention, (a) is a figure which shows the example of a sequence which forms a stack film, (b) It is a figure which shows the example of a sequence which forms a laminate film. (A)-(f) is a figure which shows the chemical structural formula of various silanes used as source gas, and is a figure which shows the chemical structural formula of BTCSM, BTCSE, TCMDDS, DCTMDS, HCDS, BDEAS, respectively. (A)-(f) is a figure which shows the name of various amines used as catalyst gas, a chemical composition formula, a chemical structural formula, and an acid dissociation constant, respectively, cyclic amine, TEA, DEA, MEA, TMA, It is a figure which shows the name of MMA, a chemical composition formula, a chemical structural formula, and an acid dissociation constant. 4 is a graph of an example of the present invention, where (a) shows the relative dielectric constant of the SiOC film before and after the heat treatment, (b) shows the wet etching rate of the SiOC film before and after the heat treatment, and (c) shows the wet etching rate of the SiOC film. The temperature dependence of the heat treatment of the etching rate is shown. Is a diagram illustrating the desorption spectrum by TDS of the SiOC film before the heat treatment was formed by a deposition sequence of the first embodiment of the present invention, the desorption spectrum of (a) is H _{2 O,} (b) is Cl (C) is a graph illustrating the desorption spectrum of C ₂ H ₂ . It is a figure which shows the evaluation result of the Example of this invention, and compares the various characteristics of the SiOC film of sample 1 and the SiOC film of sample 2, and put it together in the table | surface. (A) is a figure which shows the temperature control sequence of the heat processing process at the time of making 2nd temperature higher than 1st temperature, (b)-(d) is the figure which shows the modification. It is a figure which shows the temperature control sequence of the heat processing process at the time of making 2nd temperature into temperature equivalent to 1st temperature. It is a figure which shows the evaluation result of the Example of this invention, (a) is a graph which shows the wet etching rate of the SiOC film | membrane of samples 1-6, (b) is a table | surface comparing the heat processing conditions of each sample. It is a summary. It is a figure which shows the evaluation result of the Example of this invention, and is a graph which shows the dielectric constant of the SiOC film of the samples 1-8, and the SiO film of the samples 9 and 10.

<First Embodiment>
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

(1) Overall Configuration of Substrate Processing Apparatus As shown in FIG. 1, the processing furnace 202 has a heater 207 as heating means (heating mechanism). The heater 207 has a cylindrical shape and is vertically installed by being supported by a heater base (not shown) as a holding plate. As will be described later, the heater 207 also functions as an activation mechanism (excitation unit) that activates (excites) gas with heat.

A reaction tube 203 is disposed inside the heater 207 concentrically with the heater 207. The reaction tube 203 is made of a heat-resistant material such as quartz (SiO ₂ ) or silicon carbide (SiC), and is formed in a cylindrical shape with the upper end closed and the lower end opened. A manifold (inlet flange) 209 is disposed below the reaction tube 203 concentrically with the reaction tube 203. The manifold 209 is made of, for example, a metal such as stainless steel, and is formed in a cylindrical shape with an upper end and a lower end opened. The upper end portion of the manifold 209 is engaged with the lower end portion of the reaction tube 203 and is configured to support the reaction tube 203. An O-ring 220a as a seal member is provided between the manifold 209 and the reaction tube 203. As the manifold 209 is supported by the heater base, the reaction tube 203 is installed vertically. The reaction vessel 203 and the manifold 209 mainly constitute a processing vessel (reaction vessel). A processing chamber 201 is formed in the cylindrical hollow portion of the processing container. The processing chamber 201 is configured to be able to accommodate wafers 200 as substrates in a state where they are aligned in multiple stages in a vertical posture in a horizontal posture by a boat 217 described later.

  In the processing chamber 201, nozzles 249 a to 249 c are provided so as to penetrate the side wall of the manifold 209. Gas supply pipes 232a to 232c are connected to the nozzles 249a to 249c, respectively. Gas supply pipes 232d to 232f are connected to the gas supply pipe 232a. Gas supply pipes 232g and 232h are connected to the gas supply pipe 232b. A gas supply pipe 232i is connected to the gas supply pipe 232c. As described above, the processing container is provided with the three nozzles 249 a to 249 c and the plurality of gas supply pipes 232 a to 232 i so that a plurality of types of gases can be supplied into the processing chamber 201. It is configured.

  The gas supply pipes 249a to 249i are respectively provided with mass flow controllers (MFC) 241a to 241i as flow rate controllers (flow rate control units) and valves 243a to 243i as opening / closing valves in order from the upstream direction. Gas supply pipes 232j to 232l for supplying an inert gas are connected to downstream sides of the valves 243a to 243c of the gas supply pipes 232a to 232c, respectively. The gas supply pipes 232j to 232l are respectively provided with MFCs 241j to 241l and valves 243j to 243l in order from the upstream direction.

  Nozzles 249a and 249c are connected to the distal ends of the gas supply pipes 232a and 232c, respectively. As shown in FIG. 2, the nozzles 249 a and 249 c are arranged in an annular space between the inner wall of the reaction tube 203 and the wafer 200, along the upper portion from the lower portion of the inner wall of the reaction tube 203 in the stacking direction of the wafer 200. It is provided to stand up towards each. In other words, the nozzles 249a and 249c are respectively provided along the wafer arrangement area in areas horizontally surrounding the wafer arrangement area on the side of the wafer arrangement area where the wafers 200 are arranged. The nozzles 249a and 249c are respectively configured as L-shaped long nozzles, and their horizontal portions are provided so as to penetrate the side wall of the manifold 209, and each vertical portion thereof is at least one end of the wafer arrangement region. It is provided so as to rise from the side toward the other end side. Gas supply holes 250a and 250c for supplying gas are provided on the side surfaces of the nozzles 249a and 249c, respectively. The gas supply holes 250 a and 250 c are opened so as to face the center of the reaction tube 203, and gas can be supplied toward the wafer 200. A plurality of gas supply holes 250a and 250c are provided from the lower part to the upper part of the reaction tube 203, each having the same opening area, and further provided at the same opening pitch.

  A nozzle 249b is connected to the tip of the gas supply pipe 232b. The nozzle 249b is provided in a buffer chamber 237 that is a gas dispersion space. As shown in FIG. 2, the buffer chamber 237 is formed in an annular space between the inner wall of the reaction tube 203 and the wafer 200, and in a portion extending from the lower portion to the upper portion of the inner wall of the reaction tube 203 in the loading direction of the wafer 200. It is provided along. That is, the buffer chamber 237 is provided on the side of the wafer arrangement area, in a region that horizontally surrounds the wafer arrangement area, along the wafer arrangement area. A gas supply hole 250 d for supplying a gas is provided at the end of the wall of the buffer chamber 237 adjacent to the wafer 200. The gas supply hole 250 d is opened so as to face the center of the reaction tube 203, and gas can be supplied toward the wafer 200. A plurality of gas supply holes 250d are provided from the lower part to the upper part of the reaction tube 203, each having the same opening area, and further provided at the same opening pitch.

  The nozzle 249b rises upward from the lower end of the inner wall of the reaction tube 203 upward in the stacking direction of the wafer 200 at the end opposite to the end where the gas supply hole 250d of the buffer chamber 237 is provided. Is provided. That is, the nozzle 249b is provided along the wafer arrangement region in a region that horizontally surrounds the wafer arrangement region on the side of the wafer arrangement region where the wafers 200 are arranged. The nozzle 249b is configured as an L-shaped long nozzle, and its horizontal portion is provided so as to penetrate the side wall of the manifold 209, and its vertical portion extends at least from one end side to the other end side of the wafer arrangement region. To stand up. A gas supply hole 250b for supplying gas is provided on the side surface of the nozzle 249b. The gas supply hole 250 b is opened to face the center of the buffer chamber 237. As with the gas supply hole 250d, a plurality of gas supply holes 250b are provided from the lower part to the upper part of the reaction tube 203. When the differential pressure between the buffer chamber 237 and the processing chamber 201 is small, the opening area and the opening pitch of the plurality of gas supply holes 250b may be the same from the upstream side (lower part) to the downstream side (upper part). Further, when the differential pressure between the buffer chamber 237 and the processing chamber 201 is large, the opening area of the gas supply holes 250b is gradually increased from the upstream side to the downstream side, or the opening pitch of the gas supply holes 250b is increased upstream. It is good to make it gradually smaller from the side toward the downstream side.

  By adjusting the opening area and the opening pitch of each gas supply hole 250b from the upstream side to the downstream side as described above, the flow rate is almost the same from each of the gas supply holes 250b, although there is a difference in flow velocity. A certain gas can be ejected. Then, once the gas ejected from each of the plurality of gas supply holes 250b is introduced into the buffer chamber 237, the difference in gas flow velocity can be made uniform in the buffer chamber 237. The gas jetted into the buffer chamber 237 from each of the gas supply holes 250b is jetted into the processing chamber 201 through the gas supply holes 250d after the particle velocity of each gas is reduced in the buffer chamber 237. The gas ejected into the buffer chamber 237 from each of the plurality of gas supply holes 250b becomes a gas having a uniform flow rate and flow velocity when ejected into the processing chamber 201 from each of the gas supply holes 250d.

  As described above, in this embodiment, the nozzles are arranged in an annular vertically long space defined by the inner wall of the reaction tube 203 and the ends of the stacked wafers 200, that is, in a cylindrical space. Gas is conveyed via 249a to 249c and the buffer chamber 237. Then, gas is first ejected into the reaction tube 203 from the gas supply holes 250 a to 250 d opened in the nozzles 249 a to 249 c and the buffer chamber 237, respectively, in the vicinity of the wafer 200. The main flow of gas in the reaction tube 203 is a direction parallel to the surface of the wafer 200, that is, a horizontal direction. By adopting such a configuration, it is possible to supply gas uniformly to each wafer 200, and it is possible to improve the uniformity of the film thickness formed on each wafer 200. The gas flowing on the surface of the wafer 200, that is, the residual gas after the reaction, flows toward the exhaust port, that is, the direction of the exhaust pipe 231 described later. However, the direction of the remaining gas flow is appropriately specified depending on the position of the exhaust port, and is not limited to the vertical direction.

From the gas supply pipe 232a, as a source gas containing a predetermined element, C and a halogen element, and having a chemical bond between the predetermined element and C, for example, containing Si, an alkylene group and a halogen group as the predetermined element, Si and C An alkylenehalosilane source gas having a chemical bond (Si—C bond) is supplied into the processing chamber 201 through the MFC 241a, the valve 243a, and the nozzle 249a. An alkylene group is a functional group obtained by removing two hydrogens (H) from a chain saturated hydrocarbon (alkane) represented by the general formula C _n H _{2n + 2} , and is an atom of the atom represented by the general formula C _n H _2n. It is an aggregate. The alkylene group includes a methylene group, an ethylene group, a propylene group, a butylene group and the like. The halogen group includes a chloro group, a fluoro group, a bromo group and the like. That is, the halogen group includes a halogen element such as chlorine (Cl), fluorine (F), bromine (Br) and the like.

As the alkylene halosilane source gas, for example, Si, a source gas containing a methylene group (—CH ₂ —) as an alkylene group and a chloro group (Cl) as a halogen group, that is, a chlorosilane source gas containing a methylene group, A source gas containing Si, an ethylene group (—C ₂ H ₄ —) as an alkylene group, and a chloro group (Cl) as a halogen group, that is, a chlorosilane source gas containing an ethylene group can be used. As the chlorosilane source gas containing a methylene group, for example, methylene bis (trichlorosilane) gas, that is, bis (trichlorosilyl) methane ((SiCl ₃ ) ₂ CH ₂ , abbreviation: BTCSM) gas, or the like can be used. As the chlorosilane source gas containing an ethylene group, for example, ethylene bis (trichlorosilane) gas, that is, 1,2-bis (trichlorosilyl) ethane ((SiCl ₃ ) ₂ C ₂ H ₄ , abbreviation: BTCSE) gas, etc. Can be used.

  As shown in FIG. 9A, BTCSM includes one methylene group as an alkylene group in its chemical structural formula (in one molecule). The two bonds that the methylene group has are each bonded to Si to form a Si—C—Si bond.

  As shown in FIG. 9B, BTCSE includes one ethylene group as an alkylene group in one molecule. The two bonds that the ethylene group has are each bonded to Si, forming a Si—C—C—Si bond.

The gas supply pipe 232d includes a predetermined element, C, and a halogen element, and includes, for example, Si, an alkyl group, and a halogen group as a predetermined element as a source gas having a chemical bond between the predetermined element and C, and Si—C The alkylhalosilane source gas having a bond is supplied into the processing chamber 201 through the MFC 241d, the valve 243d, and the nozzle 249a. The alkyl group is a functional group obtained by removing one H from a chain saturated hydrocarbon represented by the general formula C _n H _{2n + 2} , and is an aggregate of atoms represented by the general formula C _n H _{2n + 1} . Alkyl groups include methyl, ethyl, propyl, butyl and the like. The halogen group includes a chloro group, a fluoro group, a bromo group, that is, a halogen element such as Cl, F, or Br.

As the alkylhalosilane source gas, for example, a source gas containing Si, a methyl group (—CH ₃ ) as an alkyl group and a chloro group (Cl) as a halogen group, that is, a chlorosilane source gas containing a methyl group is used. Can do. As a chlorosilane source gas containing a methyl group, for example, 1,1,2,2-tetrachloro-1,2-dimethyldisilane ((CH ₃ ) ₂ Si ₂ Cl 4, abbreviated as TCMDDS) gas, 1,2-dichloro -1,1,2,2-tetramethyldisilane ((CH ₃ ) ₄ Si ₂ Cl ₂ , abbreviation: DCTMDS) gas, 1-monochloro-1,1,2,2,2-pentamethyldisilane ((CH ₃ ) ₅ Si ₂ Cl (abbreviation: MCPMDS) gas or the like can be used. The alkylhalosilane source gas such as TCMDDS gas and DCTMDS gas is different from the alkylene halosilane gas source gas such as BTCSE gas and BTCSM gas, and has a gas having Si—Si bond, that is, a predetermined element and a halogen element, It is also a raw material gas having a chemical bond between them.

  As shown in FIG. 9C, TCDMDS contains two methyl groups as alkyl groups in one molecule. Each bond that the two methyl groups have is bonded to Si, forming a Si—C bond. TCDMDS is a derivative of disilane and has a Si—Si bond. That is, TCDMDS has a Si—Si—C bond in which Si bonds and Si and C bond.

  As shown in FIG. 9D, DCTMDS includes four methyl groups as alkyl groups in one molecule. Each bond of the four methyl groups is bonded to Si to form a Si—C bond. DCTMDS is a derivative of disilane and has a Si—Si bond. That is, DCTMDS has a Si—Si—C bond in which Si bonds and Si and C bond.

  From the gas supply pipe 232e, as a source gas containing Si and a halogen element as predetermined elements, for example, a halosilane source gas containing Si and a halogen element and having a chemical bond between Si (Si—Si bond) is MFC241e, The gas is supplied into the processing chamber 201 through the valve 243e and the nozzle 249a.

As the halosilane source gas, for example, a source gas containing Si and a chloro group (Cl) as a halogen element and having a Si—Si bond, that is, a chlorosilane source gas can be used. The chlorosilane source gas is a silane source gas containing a chloro group, and is a source gas containing at least Si and Cl as a halogen element. That is, it can be said that the chlorosilane raw material here is a kind of halide. As the chlorosilane source gas supplied from the gas supply pipe 232e, for example, hexachlorodisilane (Si ₂ Cl ₆ , abbreviation: HCDS) gas can be used.

As shown in FIG. 9 (e), HCDS contains two Si and six chloro groups in one molecule. As source gases containing Si and a halogen element, in addition to HCDS gas, tetrachlorosilane, that is, silicon tetrachloride (SiCl ₄ , abbreviation: STC) gas, trichlorosilane (SiHCl ₃ , abbreviation: TCS) gas, dichlorosilane (SiH) An inorganic source gas such as ₂ Cl ₂ , abbreviation: DCS) gas, or monochlorosilane (SiH ₃ Cl, abbreviation: MCS) gas can be used.

  From the gas supply pipe 232f, as a source gas containing Si, C and nitrogen (N) as predetermined elements and having a chemical bond (Si—N bond) between Si and N, for example, Si and amino groups (amine groups) ) Is supplied into the processing chamber 201 through the MFC 241f, the valve 243f, and the nozzle 249a.

The aminosilane source gas is a silane source gas containing an amino group, and is a source gas containing at least Si and an amino group containing C and N. As the aminosilane source gas supplied from the gas supply pipe 232f, for example, bis (diethylamino) silane (Si [N (C ₂ H ₅ ) ₂ ] ₂ H ₂ , abbreviation: BDEAS) gas can be used.

As shown in FIG. 9 (f), BDEAS includes one Si and two amino groups in one molecule. As a source gas containing Si, C and N and having a Si—N bond, in addition to BDEAS gas, tris (diethylamino) silane (SiH [N (C ₂ H ₅ ) ₂ ] ₃ , abbreviation: 3DEAS) gas, tetrakis ( Diethylamino) silane (Si [N (C ₂ H ₅ ) ₂ ] ₄ , abbreviation: 4DEAS) gas, tris (dimethylamino) silane (Si [N (CH ₃ ) ₂ ] ₃ H, abbreviation: 3DMAS) gas, tetrakis ( An organic raw material gas such as dimethylamino) silane (Si [N (CH ₃ ) ₂ ] ₄ , abbreviation: 4DMAS) gas can be used.

  Here, the raw material gas is a raw material in a gaseous state, for example, a gas obtained by vaporizing a raw material that is in a liquid state under normal temperature and normal pressure, or a raw material that is in a gaseous state under normal temperature and normal pressure. In the present specification, when the term “raw material” is used, it means “a liquid raw material in a liquid state”, “a raw material gas in a gaseous state”, or both. is there. When using a liquid material that is in a liquid state at normal temperature and pressure, such as BTCSM, BTCSE, TCDMDS, DCTMDS, HCDS, and BDEAS, the liquid material is vaporized by a vaporization system such as a vaporizer or bubbler, and the raw material gas (BTCSM gas , BTCSE gas, TCDMDS gas, DCTMDS gas, HCDS gas, BDEAS gas).

From the gas supply pipe 232b, for example, a gas containing oxygen (O) (oxygen-containing gas) is supplied as an oxidizing gas into the processing chamber 201 through the MFC 241b, the valve 243b, the nozzle 249b, and the buffer chamber 237. As the oxidizing gas supplied from the gas supply pipe 232b, for example, water vapor (H ₂ O gas) can be used. When supplying H ₂ O gas, oxygen (O ₂ ) gas and hydrogen (H ₂ ) gas are supplied to an external combustion apparatus (not shown) and burned to generate and supply H ₂ O gas. It is good.

From the gas supply pipe 232g, for example, an O-containing gas (oxygen-containing gas) is supplied as an oxidizing gas into the processing chamber 201 through the MFC 241g, the valve 243g, the nozzle 249b, and the buffer chamber 237. As the oxidizing gas supplied from the gas supply pipe 232g, for example, ozone (O ₃ ) gas can be used.

From the gas supply pipe 232h, for example, an O-containing gas (oxygen-containing gas) is supplied into the processing chamber 201 through the MFC 241h, the valve 243h, the nozzle 249b, and the buffer chamber 237 as an oxidizing gas. As an oxidizing gas supplied from the gas supply pipe 232h, for example, oxygen (O ₂ ) gas can be used.

From the gas supply pipe 232c, the surface of the wafer 200 or the bonding force of the O—H bond of the H ₂ O gas is weakened by the catalytic action, the decomposition of the raw material gas is promoted, and the oxidation of the H ₂ O gas or the like. For example, an amine-based gas containing C, N, and H is supplied into the processing chamber 201 via the MFC 241c, the valve 243c, and the nozzle 249c as the catalyst gas that promotes the oxidation reaction by the gas.

The amine-based gas is a gas containing an amine in which at least one of H in ammonia (NH ₃ ) is substituted with a hydrocarbon group such as an alkyl group. As shown in FIG. 10, the various amines used as the catalyst gas include, for example, N having a lone electron pair, and have an acid dissociation constant (hereinafter also referred to as pKa) of about 5 to 11. The acid dissociation constant (pKa) is one of the indexes that quantitatively express the strength of the acid, and is an equilibrium constant Ka in the dissociation reaction in which H ions are released from the acid, expressed as a negative common logarithm. As the amine-based gas, a cyclic amine-based gas in which a hydrocarbon group is cyclic or a chain amine-based gas in which a hydrocarbon group is chained can be used. As the amine-based gas supplied from the gas supply pipe 232c, for example, a pyridine (C ₅ H ₅ N) gas that is a cyclic amine-based gas can be used.

As the cyclic amine-based gas, as shown in FIG. 10A, for example, pyridine (C ₅ H ₅ N, pKa = 5.67) gas, aminopyridine (C ₅ H ₆ N ₂ , pKa = 6.89) Gas, picoline (C ₆ H ₇ N, pKa = 6.07) gas, lutidine (C ₇ H ₉ N, pKa = 6.96) gas, piperazine (C ₄ H ₁₀ N ₂ , pKa = 9.80) gas Piperidine (C ₅ H ₁₁ N, pKa = 11.12) gas or the like can be used. It can be said that the cyclic amine-based gas is a heterocyclic compound having a cyclic structure composed of a plurality of kinds of elements of C and N, that is, a nitrogen-containing heterocyclic compound.

From the gas supply pipe 232i, for example, an amine-based gas containing C, N, and H is provided in the processing chamber 201 via the MFC 241i, the valve 243i, and the nozzle 249c as a catalyst gas having the same catalytic action as the cyclic amine-based gas. Supplied to. As the amine-based gas supplied from the gas supply pipe 232i, for example, a triethylamine ((C ₂ H ₅ ) ₃ N, abbreviated as TEA) gas that is a chain amine-based gas can be used.

As the chain amine-based gas, as shown in FIGS. 10B to 10F, for example, triethylamine ((C ₂ H ₅ ) ₃ N, abbreviation: TEA, pKa = 10.7) gas, diethylamine (( C ₂ H ₅ ) ₂ NH, abbreviation: DEA, pKa = 10.9) gas, monoethylamine ((C ₂ H ₅ ) NH ₂ , abbreviation: MEA, pKa = 10.6) gas, trimethylamine ((CH ₃ ) ₃ N, abbreviation: TMA, pKa = 9.8) gas, monomethylamine ((CH ₃ ) NH ₂ , abbreviation: MMA, pKa = 10.6) gas, or the like can be used.

An amine-based gas that acts as a catalyst gas can also be referred to as an amine-based catalyst gas. As the catalyst gas, in addition to the above-described amine-based gas, a non-amine-based gas such as ammonia (NH ₃ , pKa = 9.2) gas or the like can also be used.

  In the catalyst gas exemplified here, a part of the molecular structure may be decomposed in the thin film forming process described later. Strictly speaking, such a gas that partially changes before and after a chemical reaction is not a “catalyst”. However, in the present specification, even when a part of the chemical reaction is decomposed in the course of the chemical reaction, most of the substance is not decomposed, and the substance that changes the rate of the reaction and substantially acts as a catalyst, This is referred to as “catalyst”.

From the gas supply pipes 232j to 232l, for example, as an inert gas, for example, nitrogen (N ₂ ) gas is MFCs 241j to 241l, valves 243j to 243l, gas supply pipes 232a to 232c, nozzles 249a to 249c, and a buffer chamber 237, respectively. Is supplied into the processing chamber 201.

The N ₂ gas also acts as a purge gas, and also acts as an oxygen-free gas that does not contain O and generates an oxygen-free atmosphere described later. When N ₂ gas is used as an oxygen-free gas, the N ₂ gas may also act as a heat treatment gas or an annealing gas. As the inert gas, purge gas, and oxygen-free gas, in addition to N ₂ gas, for example, rare gas such as argon (Ar) gas, helium (He) gas, neon (Ne) gas, xenon (Xe) gas, etc. Can be used.

  When the gas as described above is caused to flow from each gas supply pipe, the source gas is mainly supplied from the gas supply pipes 232a, 232d, 232e, 232f, MFCs 241a, 241d, 241e, 241f, and valves 243a, 243d, 243e, 243f. A source gas supply system to be supplied is configured. The nozzle 249a may be included in the source gas supply system. The source gas supply system can also be referred to as a source supply system. A source gas supply system may be regarded as an aggregate of a plurality of supply lines (supply systems) that supply a plurality of types of source gases that are element sources of different elements or a plurality of types of source gases that have different molecular structures. it can. That is, the source gas supply system includes a BTCSM gas supply line mainly configured by a gas supply pipe 232a, an MFC 241a, and a valve 243a, and a TCDMDS gas supply line mainly configured by a gas supply pipe 232d, an MFC 241d, and a valve 243d; It can be said that this is an aggregate of an HCDS gas supply line mainly composed of the gas supply pipe 232e, the MFC 241e and the valve 243e and a BDEAS gas supply line mainly composed of the gas supply pipe 232f, the MFC 241f and the valve 243f. You may consider including the nozzle 249a in each supply line.

  In this way, the plurality of supply lines constituting the source gas supply system are configured to supply a plurality of types of source gases serving as element sources for different elements and a plurality of types of source gases having different molecular structures, respectively. Yes. Each source gas has a different molecular structure, that is, a different chemical structural formula. The composition and components of each source gas may be different. Source gases having different molecular structures have different chemical properties. Therefore, as will be described later, by appropriately selecting the type of the source gas according to the desired film forming process, various composition ratios and film quality thin films can be used for a single substrate processing apparatus. It becomes possible to form with good reproducibility.

Further, an oxidizing gas supply system is mainly constituted by the gas supply pipes 232b, 232g, 232h, the MFCs 241b, 241g, 241h, and the valves 243b, 243g, 243h. The nozzle 249b and the buffer chamber 237 may be included in the oxidizing gas supply system. The oxidizing gas supply system can also be referred to as an oxidant supply system. The oxidizing gas supply system can also be regarded as an assembly of a plurality of supply lines (supply systems) for supplying a plurality of types of oxidizing gases having different molecular structures. That is, the oxidizing gas supply system includes an H ₂ O gas supply line mainly composed of the gas supply pipe 232b, the MFC 241b and the valve 243b, and an O ₃ gas supply mainly composed of the gas supply pipe 232g, the MFC 241g and the valve 243g. It can be said that this is an assembly of a line and an O ₂ gas supply line mainly composed of a gas supply pipe 232h, an MFC 241h, and a valve 243h. You may consider including the nozzle 249b and the buffer chamber 237 in each supply line.

  Thus, the plurality of supply lines constituting the oxidizing gas supply system are configured to supply a plurality of types of oxidizing gases having different molecular structures, respectively. Each oxidizing gas has a different molecular structure, that is, a different chemical structural formula. The composition and components of each oxidizing gas may be different. Oxidizing gases having different molecular structures have different chemical properties. Therefore, for example, by appropriately selecting the type of oxidizing gas according to the desired film forming process, various composition ratios and film quality thin films can be used for general purpose and with good reproducibility in one substrate processing apparatus. It becomes possible to form.

  Further, a catalyst gas supply system is mainly configured by the gas supply pipes 232c and 232i, the MFCs 241c and 241i, and the valves 243c and 243i. The nozzle 249c may be included in the catalyst gas supply system. The catalyst gas supply system can also be regarded as an assembly of a plurality of supply lines (supply systems) for supplying a plurality of types of catalyst gases having different molecular structures. That is, the catalyst gas supply system includes a pyridine gas supply line mainly constituted by a gas supply pipe 232c, an MFC 241c and a valve 243c, a TEA gas supply line mainly constituted by the gas supply pipe 232i, the MFC 241i and the valve 243i, It can be said that it is an aggregate of. You may consider including the nozzle 249c in each supply line. Further, pyridine gas and TEA gas can be said to be amine-based gas as a catalyst, that is, amine-based catalyst gas, as will be described later. Hereinafter, the catalyst gas supply system for supplying various amine catalyst gases is also referred to as an amine catalyst gas supply system.

  Thus, the plurality of supply lines constituting the catalyst gas supply system are configured to supply a plurality of types of catalyst gases having different molecular structures. Each catalyst gas has a different molecular structure, that is, a different chemical structural formula. The composition and components of each catalyst gas may be different. The catalyst gases having different molecular structures have different chemical properties. Therefore, as will be described later, by appropriately selecting the type of the catalyst gas according to the desired film forming process, various composition ratios and film-quality thin films can be used for one substrate processing apparatus. It becomes possible to form with good reproducibility.

  Further, an inert gas supply system is mainly configured by the gas supply pipes 232j to 232l, the MFCs 241j to 241l, and the valves 243j to 243l. The inert gas supply system may include the nozzles 249a to 249c and the buffer chamber 237 on the downstream side of the gas supply pipes 232a to 232c connected to the gas supply pipes 232j to 232l. The inert gas supply system can be regarded as an assembly of a plurality of supply lines. That is, the inert gas supply system includes an inert gas supply line mainly composed of the gas supply pipe 232j, the MFC 241j, and the valve 243j, and an inert gas supply mainly composed of the gas supply pipe 232k, the MFC 241k, and the valve 243k. It can be said that this is an assembly of a line and an inert gas supply line mainly composed of a gas supply pipe 232l, an MFC 241l, and a valve 243l. The inert gas supply system also functions as a purge gas supply system and an oxygen-free gas supply system. Note that the oxygen-free gas supply system constitutes a part of an atmosphere generation unit that generates an oxygen-free atmosphere described later.

  Any or all of the above-described source gas supply system, oxidizing gas supply system, catalyst gas supply system, and inert gas supply system may be referred to as a process gas supply system.

  In the buffer chamber 237, as shown in FIG. 2, two rod-shaped electrodes 269 and 270 made of a conductor and having an elongated structure are arranged along the stacking direction of the wafer 200 from the lower part to the upper part of the reaction tube 203. It is installed. Each of the rod-shaped electrodes 269 and 270 is provided in parallel with the nozzle 249d. Each of the rod-shaped electrodes 269 and 270 is protected by being covered with an electrode protection tube 275 from the upper part to the lower part. One of the rod-shaped electrodes 269 and 270 is connected to the high-frequency power source 273 via the matching unit 272, and the other is connected to the ground that is the reference potential. By applying radio frequency (RF) power between the rod-shaped electrodes 269 and 270 from the high-frequency power source 273 via the matching device 272, plasma is generated in the plasma generation region 224 between the rod-shaped electrodes 269 and 270. The rod-shaped electrodes 269 and 270 and the electrode protection tube 275 mainly constitute a plasma source as a plasma generator (plasma generator). The matching device 272 and the high-frequency power source 273 may be included in the plasma source. The plasma source functions as an activation mechanism (excitation unit) that activates (excites) gas into a plasma state.

The electrode protection tube 275 has a structure in which each of the rod-shaped electrodes 269 and 270 can be inserted into the buffer chamber 237 while being isolated from the atmosphere in the buffer chamber 237. When the oxygen concentration inside the electrode protection tube 275 is approximately the same as the oxygen concentration in the outside air (atmosphere), the rod-shaped electrodes 269 and 270 inserted into the electrode protection tube 275 are oxidized by heat from the heater 207. . Or it is filled with an inert gas such as N ₂ gas into the electrode protection tube 275, by the interior of the electrode protection tube 275 is purged with an inert gas such as N ₂ gas using an inert gas purge mechanism, The oxygen concentration inside the electrode protection tube 275 is reduced, and the oxidation of the rod-shaped electrodes 269 and 270 can be suppressed.

  The reaction tube 203 is provided with an exhaust pipe 231 for exhausting the atmosphere in the processing chamber 201. The exhaust pipe 231 is connected via a pressure sensor 245 as a pressure detector (pressure detection unit) for detecting the pressure in the processing chamber 201 and an APC (Auto Pressure Controller) valve 244 as a pressure regulator (pressure adjustment unit). A vacuum pump 246 as a vacuum exhaust device is connected. The APC valve 244 can perform vacuum evacuation and vacuum evacuation stop in the processing chamber 201 by opening and closing the valve with the vacuum pump 246 activated, and further, with the vacuum pump 246 activated, The valve is configured such that the pressure in the processing chamber 201 can be adjusted by adjusting the valve opening based on the pressure information detected by the pressure sensor 245. An exhaust system is mainly configured by the exhaust pipe 231, the APC valve 244, and the pressure sensor 245. The vacuum pump 246 may be included in the exhaust system. The exhaust pipe 231 is not limited to being provided in the reaction pipe 203, and may be provided in the manifold 209 similarly to the nozzles 249a to 249c.

  An atmosphere generating unit that generates an oxygen-free atmosphere in the processing chamber 201 is mainly configured by the exhaust system and the oxygen-free gas supply system. The exhaust system evacuates the inside of the processing chamber 201 alone or in cooperation with an oxygen-free gas supply system that supplies an oxygen-free gas to the wafer 200 in the processing chamber 201, The atmosphere in the processing chamber 201 is configured to be an oxygen-free atmosphere.

  Below the manifold 209, a seal cap 219 is provided as a furnace port lid that can airtightly close the lower end opening of the manifold 209. The seal cap 219 is configured to contact the lower end of the manifold 209 from the lower side in the vertical direction. The seal cap 219 is made of a metal such as SUS and is formed in a disk shape. On the upper surface of the seal cap 219, an O-ring 220b is provided as a seal member that comes into contact with the lower end of the manifold 209. On the opposite side of the seal cap 219 from the processing chamber 201, a rotation mechanism 267 for rotating a boat 217 described later is installed. A rotation shaft 255 of the rotation mechanism 267 passes through the seal cap 219 and is connected to the boat 217. The rotation mechanism 267 is configured to rotate the wafer 200 by rotating the boat 217. The seal cap 219 is configured to be lifted and lowered in the vertical direction by a boat elevator 115 as a lifting mechanism vertically installed outside the reaction tube 203. The boat elevator 115 is configured so that the boat 217 can be carried in and out of the processing chamber 201 by moving the seal cap 219 up and down. That is, the boat elevator 115 is configured as a transfer device (transfer mechanism) that transfers the boat 217 and the wafer 200 supported by the boat 217 into and out of the processing chamber 201.

  The boat 217 as the substrate support is configured to support a plurality of, for example, 25 to 200, wafers 200 in a horizontal posture and in a multi-stage by aligning them in the vertical direction with their centers aligned. Are arranged so as to be spaced apart. The boat 217 is made of a heat-resistant material such as quartz or SiC. Under the boat 217, heat insulating plates 218 made of a heat-resistant material such as quartz or SiC are supported in multiple stages in a horizontal posture. With this configuration, heat from the heater 207 is not easily transmitted to the seal cap 219 side. However, this embodiment is not limited to the above-mentioned form. For example, instead of providing the heat insulating plate 218 in the lower portion of the boat 217, a heat insulating cylinder configured as a cylindrical member made of a heat resistant material such as quartz or SiC may be provided.

  A temperature sensor 263 is installed in the reaction tube 203 as a temperature detector. By adjusting the power supply to the heater 207 based on the temperature information detected by the temperature sensor 263, the temperature in the processing chamber 201 has a desired temperature distribution. The temperature sensor 263 is configured in an L shape like the nozzles 249 a to 249 c and is provided along the inner wall of the reaction tube 203.

  As shown in FIG. 3, the controller 121, which is a control unit (control means), is configured as a computer including a CPU (Central Processing Unit) 121a, a RAM (Random Access Memory) 121b, a storage device 121c, and an I / O port 121d. Has been. The RAM 121b, the storage device 121c, and the I / O port 121d are configured to exchange data with the CPU 121a via the internal bus 121e. For example, an input / output device 122 configured as a touch panel or the like is connected to the controller 121.

  The storage device 121c is configured by, for example, a flash memory, an HDD (Hard Disk Drive), or the like. In the storage device 121c, a control program that controls the operation of the substrate processing apparatus, a process recipe that describes the procedure and conditions of substrate processing such as thin film formation described later, and the like are stored in a readable manner. The process recipe is a combination of functions so that a predetermined result can be obtained by causing the controller 121 to execute each procedure in a substrate processing process such as a thin film forming process to be described later. Hereinafter, the process recipe, the control program, and the like are collectively referred to simply as a program. When the term “program” is used in this specification, it may include only a process recipe alone, only a control program alone, or both. The RAM 121b is configured as a memory area (work area) in which programs, data, and the like read by the CPU 121a are temporarily stored.

  The I / O port 121d includes the above-described MFCs 241a to 241l, valves 243a to 243l, pressure sensor 245, APC valve 244, vacuum pump 246, temperature sensor 263, heater 207, matching device 272, high frequency power supply 273, rotation mechanism 267, boat It is connected to the elevator 115 and the like.

  The CPU 121a is configured to read out and execute a control program from the storage device 121c, and to read out a process recipe from the storage device 121c in response to an operation command input from the input / output device 122 or the like. The CPU 121a adjusts the flow rates of various gases by the MFCs 241a to 241l, the opening and closing operations of the valves 243a to 243l, the opening and closing operations of the APC valve 244, and the pressure by the APC valve 244 based on the pressure sensor 245 so as to follow the contents of the read process recipe. Adjustment operation, start and stop of the vacuum pump 246, temperature adjustment operation of the heater 207 based on the temperature sensor 263, rotation and rotation speed adjustment operation of the boat 217 by the rotating mechanism 267, raising / lowering operation of the boat 217 by the boat elevator 115, matching unit 272 It is configured to control the impedance adjustment operation by the power supply, the power supply of the high frequency power supply 273, and the like.

  The controller 121 is not limited to being configured as a dedicated computer, and may be configured as a general-purpose computer. For example, an external storage device storing the above-described program (for example, magnetic tape, magnetic disk such as a flexible disk or hard disk, optical disk such as CD or DVD, magneto-optical disk such as MO, semiconductor memory such as USB memory or memory card) 123 is prepared, and the controller 121 of this embodiment can be configured by installing a program in a general-purpose computer using the external storage device 123. However, the means for supplying the program to the computer is not limited to supplying the program via the external storage device 123. For example, the program may be supplied without using the external storage device 123 by using communication means such as the Internet or a dedicated line. The storage device 121c and the external storage device 123 are configured as computer-readable recording media. Hereinafter, these are collectively referred to simply as a recording medium. When the term “recording medium” is used in this specification, it may include only the storage device 121c alone, may include only the external storage device 123 alone, or may include both.

(2) Thin film formation process FIG. 4A is used for a sequence example of forming a thin film on a substrate (film formation) as one process of a semiconductor device (semiconductor device) manufacturing process using the substrate processing apparatus described above. I will explain. In the following description, the operation of each part constituting the substrate processing apparatus is controlled by the controller 121.

In the film forming sequence shown in FIG.
Supplying a BTCSM gas as a source gas containing Si, C and Cl and having a Si-C bond to a wafer 200 as a substrate;
Supplying H ₂ O gas as an oxidizing gas to the wafer 200;
Supplying pyridine gas as a catalyst gas to the wafer 200;
Is performed a predetermined number of times (n times) to form a silicon oxycarbide film (hereinafter also referred to as a SiOC film) on the wafer 200 as a thin film containing Si, O, and C. This SiOC film can also be referred to as a C-containing SiO film or a C-doped (added) SiO film.

At this time,
The step of supplying the BTCSM gas is performed in the state of performing the step of supplying the pyridine gas,
The step of supplying H ₂ O gas is performed in a state where the step of supplying pyridine gas is performed.

After forming the SiOC film,
Removing the first impurities from the SiOC film by heat-treating the SiOC film at a first temperature higher than the temperature of the wafer 200 in the step of forming the SiOC film;
Removing a second impurity different from the first impurity from the SiOC film after the heat treatment at the first temperature by heat-treating the SiOC film at a second temperature equal to or higher than the first temperature; Is further performed.
These heat treatments are performed in an oxygen-free atmosphere, that is, in an oxygen-free atmosphere generated by supplying N ₂ gas as an oxygen-free gas to the wafer 200.

  In the present embodiment, each process is performed in a non-plasma atmosphere.

  In this specification, when the term “wafer” is used, it means “wafer itself” or “a laminate (aggregate) of a wafer and a predetermined layer or film formed on the surface”. In other words, it may be called a wafer including a predetermined layer or film formed on the surface. In addition, when the term “wafer surface” is used in this specification, it means “the surface of the wafer itself (exposed surface)” or “the surface of a predetermined layer or film formed on the wafer”. That is, it may mean “the outermost surface of the wafer as a laminated body”.

  In the present specification, the phrase “supplying a predetermined gas to the wafer” means “supplying a predetermined gas directly to the surface (exposed surface) of the wafer itself” or “ It may mean that a predetermined gas is supplied to a layer, a film, or the like formed on the wafer, that is, to the outermost surface of the wafer as a laminated body. Further, in this specification, when “describe a predetermined layer (or film) on the wafer” is described, “determine a predetermined layer (or film) directly on the surface (exposed surface) of the wafer itself”. This means that a predetermined layer (or film) is formed on a layer or film formed on the wafer, that is, on the outermost surface of the wafer as a laminate. There is a case.

  The use of the term “substrate” in this specification is the same as the case where the term “wafer” is used. In that case, “wafer” may be replaced with “substrate” in the above description.

(Wafer charge and boat load)
When a plurality of wafers 200 are loaded into the boat 217 (wafer charge), as shown in FIG. 1, the boat 217 supporting the plurality of wafers 200 is lifted by the boat elevator 115 and loaded into the processing chamber 201 (boat). Loaded). In this state, the seal cap 219 seals the lower end of the manifold 209 via the O-ring 220b.

(Pressure adjustment and temperature adjustment)
Vacuum is exhausted by the vacuum pump 246 so that the pressure in the processing chamber 201, that is, the pressure in the space where the wafer 200 exists becomes a desired pressure (degree of vacuum). At this time, the pressure in the processing chamber 201 is measured by the pressure sensor 245, and the APC valve 244 is feedback-controlled based on the measured pressure information. The vacuum pump 246 maintains a state in which it is always operated until at least the processing on the wafer 200 is completed. Further, the wafer 200 in the processing chamber 201 is heated by the heater 207 so as to reach a desired temperature. At this time, the power supply to the heater 207 is feedback-controlled based on the temperature information detected by the temperature sensor 263 so that the inside of the processing chamber 201 has a desired temperature distribution. Heating of the processing chamber 201 by the heater 207 is continuously performed at least until the processing on the wafer 200 is completed. However, as will be described later, when processing the wafer 200 at room temperature, the heater 207 does not need to heat the processing chamber 201. Subsequently, rotation of the boat 217 and the wafers 200 by the rotation mechanism 267 is started. The rotation of the boat 217 and the wafer 200 by the rotation mechanism 267 is continuously performed at least until the processing on the wafer 200 is completed.

(SiOC film formation process)
Thereafter, the next two steps, that is, steps 1a and 2a are sequentially executed.

[Step 1a]
(BTCSM gas + pyridine gas supply)
The valve 243a is opened and BTCSM gas is allowed to flow into the gas supply pipe 232a. The flow rate of the BTCSM gas is adjusted by the MFC 241a, supplied into the processing chamber 201 through the gas supply hole 250a, and exhausted from the exhaust pipe 231. At this time, BTCSM gas is supplied to the wafer 200. At the same time, the valve 243j is opened to allow N ₂ gas to flow into the gas supply pipe 232j. The flow rate of the N ₂ gas is adjusted by the MFC 241j, is supplied into the processing chamber 201 together with the BTCSM gas, and is exhausted from the exhaust pipe 231.

Further, the valve 243c is opened, and pyridine gas is allowed to flow into the gas supply pipe 232c. The flow rate of the pyridine gas is adjusted by the MFC 241c, supplied from the gas supply hole 250c into the processing chamber 201, and exhausted from the exhaust pipe 231. At this time, pyridine gas is supplied to the wafer 200. At the same time, the valve 243 l is opened to flow N ₂ gas into the gas supply pipe 232 l. The flow rate of the N ₂ gas is adjusted by the MFC 241 l, supplied into the processing chamber 201 together with the pyridine gas, and exhausted from the exhaust pipe 231.

Further, in order to prevent BTCSM gas and pyridine gas from entering the buffer chamber 237 and the nozzle 249b, the valve 243k is opened and N ₂ gas is allowed to flow into the gas supply pipe 232k. The N ₂ gas is supplied into the processing chamber 201 through the gas supply pipe 232b, the nozzle 249b, and the buffer chamber 237, and is exhausted from the exhaust pipe 231.

At this time, the APC valve 244 is appropriately adjusted so that the pressure in the processing chamber 201 is, for example, 1 to 13330 Pa, preferably 133 to 2666 Pa. The supply flow rate of the BTCSM gas controlled by the MFC 241a is, for example, 1 to 2000 sccm, preferably 10 to 1000 sccm. The supply flow rate of the pyridine gas controlled by the MFC 241c is, for example, 1 to 2000 sccm, preferably 10 to 1000 sccm. The supply flow rate of the N ₂ gas controlled by the MFCs 241j to 241l is, for example, a flow rate in the range of 100 to 10000 sccm. The time for supplying the BTCSM gas and pyridine gas to the wafer 200, that is, the gas supply time (irradiation time) is, for example, 1 to 100 seconds, preferably 5 to 60 seconds.

  At this time, the temperature of the heater 207 is such that the temperature of the wafer 200 becomes a temperature in the range of, for example, room temperature to 150 ° C., preferably room temperature to 100 ° C., more preferably 50 ° C. to 100 ° C. Set. When the catalyst gas is not supplied when the BTCSM gas is supplied, if the temperature of the wafer 200 is less than 250 ° C., BTCSM is difficult to be chemically adsorbed on the wafer 200, and a practical film formation rate may not be obtained. By supplying pyridine gas as the catalyst gas as in this embodiment, this can be eliminated even if the temperature of the wafer 200 is less than 250 ° C. By setting the temperature of the wafer 200 to 150 ° C. or lower, and further to 100 ° C. or lower in the presence of pyridine gas, the amount of heat applied to the wafer 200 can be reduced, and the thermal history received by the wafer 200 is controlled well. be able to. In the presence of pyridine gas, if the temperature of the wafer 200 is room temperature or higher, BTCSM can be sufficiently adsorbed on the wafer 200, and a sufficient film formation rate can be obtained. Therefore, the temperature of the wafer 200 is set to a temperature in the range of room temperature to 150 ° C., preferably room temperature to 100 ° C., more preferably 50 ° C. to 100 ° C.

  By supplying BTCSM gas to the wafer 200 under the above-described conditions, a C layer having a thickness of, for example, less than one atomic layer to several atomic layers is formed on the wafer 200 (surface underlayer) as a first layer. Then, a Si-containing layer containing Cl and Cl is formed. The Si-containing layer containing C and Cl may be a Si layer containing C and Cl, an adsorption layer of BTCSM gas, or both.

  The Si layer containing C and Cl is a generic name including a continuous layer composed of Si and containing C and Cl, as well as a discontinuous layer and a Si thin film containing C and Cl formed by overlapping them. . A continuous layer made of Si and containing C and Cl may be referred to as a Si thin film containing C and Cl. Si constituting the Si layer containing C and Cl includes not only completely broken bonds with C and Cl but also completely broken bonds with C and Cl.

  The BTCSM gas adsorption layer includes a discontinuous adsorption layer as well as a continuous adsorption layer of gas molecules of the BTCSM gas. That is, the BTCSM gas adsorbing layer includes an adsorbing layer having a thickness of less than one molecular layer composed of BTCSM molecules or less than one molecular layer. The BTCSM molecules constituting the BTCSM gas adsorption layer are not only those having the chemical structural formula shown in FIG. 9A, but also those in which the bond between Si and C is partially broken, or the bond between Si and Cl is one. Includes parts that have been cut off. That is, the BTCSM gas adsorption layer may be a BTCSM molecule physical adsorption layer, a BTCSM molecule chemisorption layer, or both of them.

  Here, a layer having a thickness of less than one atomic layer means an atomic layer formed discontinuously, and a layer having a thickness of one atomic layer means an atomic layer formed continuously. Means. A layer having a thickness of less than one molecular layer means a molecular layer formed discontinuously, and a layer having a thickness of one molecular layer means a molecular layer formed continuously. ing. The Si-containing layer containing C and Cl may include both an Si layer containing C and Cl and an adsorption layer of BTCSM gas. However, as described above, expressions such as “one atomic layer” and “several atomic layer” are used for the Si-containing layer containing C and Cl.

  When the thickness of the Si-containing layer containing C and Cl as the first layer formed on the wafer 200 exceeds several atomic layers, the action of oxidation in step 2a described later reaches the entire first layer. Disappear. The minimum thickness of the first layer that can be formed on the wafer 200 is less than one atomic layer. Accordingly, it is preferable that the thickness of the first layer be less than one atomic layer to several atomic layers. By setting the thickness of the first layer to 1 atomic layer or less, that is, 1 atomic layer or less than 1 atomic layer, the action of the oxidation reaction in Step 2a described later can be relatively enhanced, and in Step 2a It is also possible to shorten the time required for the oxidation reaction. The time required for forming the first layer in step 1a can also be shortened. As a result, the processing time per cycle can be shortened, and the total processing time can be shortened. That is, the film forming rate can be increased. Further, by controlling the thickness of the first layer to 1 atomic layer or less, it becomes possible to improve the controllability of film thickness uniformity.

  Under conditions where the BTCSM gas undergoes self-decomposition (pyrolysis), that is, under conditions where a thermal decomposition reaction of BTCSM occurs, Si is deposited on the wafer 200 to form a Si layer containing C and Cl. Under the condition that the BTCSM gas is not self-decomposed (thermally decomposed), that is, under the condition where the thermal decomposition reaction of BTCSM does not occur, the BTCSM gas adsorbing layer is formed by adsorbing the BTCSM gas on the wafer 200. It is preferable to form a Si layer containing C and Cl on the wafer 200 rather than forming an adsorption layer of BTCSM gas on the wafer 200 because the deposition rate can be increased. However, in this embodiment, since the temperature of the wafer 200 is set to a low temperature of, for example, 150 ° C. or lower, a BTCSM gas adsorption layer is formed on the wafer 200 rather than the Si layer containing C and Cl formed on the wafer 200. There is a possibility that the formation will be superior. Further, when the catalyst gas is not supplied, in the BTCSM gas adsorption layer, the physical adsorption state in which the bond to the base such as the surface of the wafer 200 or the bond between the BTCSM molecules is weaker than the chemical adsorption is dominant. there is a possibility. That is, when the catalyst gas is not supplied, the BTCSM gas adsorption layer may be mostly composed of the BTCSM gas physical adsorption layer.

  The pyridine gas acts as a catalyst gas that weakens the bonding force of the O—H bond existing on the surface of the wafer 200, promotes the decomposition of the BTCSM gas, and promotes the formation of the first layer by chemisorption of BTCSM molecules. For example, as shown in FIG. 5A, the pyridine gas acts on the O—H bond existing on the surface of the wafer 200 and weakens the bonding force between O—H. The reaction between the weakened H and Cl of the BTCSM gas produces a gaseous substance containing Cl and H such as HCl, and H is desorbed from the surface of the wafer 200 and Cl is desorbed from the BTCSM molecules. Release. BTCSM molecules (halides) that have lost Cl are chemically adsorbed on the surface of the wafer 200 or the like. Thereby, a BTCSM gas chemical adsorption layer is formed on the surface of the wafer 200 or the like.

The reason why the pyridine gas weakens the bonding force between O and H is that N having a lone electron pair in the pyridine molecule has an action of attracting H. For example, the above-mentioned acid dissociation constant (pKa) can be used as an index for the magnitude of the action of a predetermined compound containing N or the like to attract H. As described above, pKa is a constant expressed as a negative common logarithm of the equilibrium constant Ka in the dissociation reaction in which H ions are released from the acid, and a compound having a large pKa has a strong ability to attract H. For example, by using a compound having a pKa of 5 or more as the catalyst gas, it is possible to promote the formation of the first layer by promoting the decomposition of the BTCSM gas. On the other hand, when the pKa of the catalyst gas is excessively large, Cl extracted from the BTCSM molecule is combined with the catalyst gas, thereby producing a salt (Salt: ionic compound) such as ammonium chloride (NH ₄ Cl), It may be a particle source. In order to suppress this, it is desirable that the pKa of the catalyst gas is about 11 or less, preferably 7 or less. Pyridine gas has a relatively large pKa of about 5.67 and has a strong ability to attract H. Further, since pKa is 7 or less, particles are hardly generated.

(Residual gas removal)
After the first layer is formed, the valve 243a is closed and the supply of BTCSM gas is stopped. Further, the valve 243c is closed and the supply of pyridine gas is stopped. At this time, the APC valve 244 is kept open, the inside of the processing chamber 201 is evacuated by the vacuum pump 246, and BTCSM gas and pyridine after contributing to the formation of the unreacted or first layer remaining in the processing chamber 201 The gas is removed from the processing chamber 201. Further, the supply of N ₂ gas into the processing chamber 201 is maintained while the valves 243j to 243l remain open. The N ₂ gas acts as a purge gas, thereby enhancing the effect of removing BTCSM gas and pyridine gas remaining in the processing chamber 201 or contributing to the formation of the first layer from the processing chamber 201. Can do.

At this time, the gas remaining in the processing chamber 201 may not be completely removed, and the inside of the processing chamber 201 may not be completely purged. If the amount of gas remaining in the processing chamber 201 is very small, no adverse effects will occur in the subsequent step 2a. The flow rate of the N ₂ gas supplied into the processing chamber 201 does not need to be a large flow rate. For example, by supplying an amount similar to the volume of the reaction tube 203 (processing chamber 201), an adverse effect occurs in step 2a. There can be no purging. Thus, by not completely purging the inside of the processing chamber 201, the purge time can be shortened and the throughput can be improved. It is also possible to minimize the consumption of N ₂ gas.

As the source gas, for example, BTCSE gas, TCMDDS gas, DCTMDS gas, etc. can be used in addition to BTCSM gas. Examples of the catalyst gas include pyridine gas, cyclic amine gases such as aminopyridine gas, picoline gas, lutidine gas, piperazine gas, and piperidine gas, and chains such as TEA gas, DEA gas, MEA gas, TMA gas, and MMA gas. A non-amine gas such as a gaseous amine gas or NH ₃ gas can be used. As the inert gas, for example, a rare gas such as Ar gas, He gas, Ne gas, and Xe gas can be used in addition to N ₂ gas.

[Step 2a]
(H ₂ O gas + pyridine gas supply)
After step 1a is completed, the valve 243b is opened and H ₂ O gas is allowed to flow into the gas supply pipe 232b. The flow rate of the H ₂ O gas is adjusted by the MFC 241 b, supplied from the gas supply hole 250 b into the buffer chamber 237, supplied from the gas supply hole 250 d into the processing chamber 201, and exhausted from the exhaust pipe 231. At this time, H ₂ O gas is supplied to the wafer 200 in a non-plasma atmosphere. At the same time, the valve 243k is opened and N ₂ gas is allowed to flow into the gas supply pipe 232k. The flow rate of the N ₂ gas is adjusted by the MFC 241k, supplied into the processing chamber 201 together with the H ₂ O gas, and exhausted from the exhaust pipe 231.

  Further, pyridine gas is supplied to the wafer 200 in the same manner as the supply of pyridine gas in step 1a.

Further, in order to prevent the invasion of H ₂ O gas and pyridine gas into the nozzle 249a, the valve 243j is opened and N ₂ gas is allowed to flow into the gas supply pipe 232j. The N ₂ gas is supplied into the processing chamber 201 through the gas supply pipe 232a and the nozzle 249a, and is exhausted from the exhaust pipe 231.

At this time, the APC valve 244 is appropriately adjusted so that the pressure in the processing chamber 201 is, for example, 1 to 13330 Pa, preferably 133 to 2666 Pa. The supply flow rate of the H ₂ O gas controlled by the MFC 241b is, for example, 1000 to 10000 sccm, preferably 10 to 1000 sccm. The supply flow rate of the pyridine gas controlled by the MFC 241c is, for example, 1 to 2000 sccm, preferably 10 to 1000 sccm. The supply flow rate of the N ₂ gas controlled by the MFCs 241j to 241l is, for example, a flow rate in the range of 100 to 10000 sccm. The time for supplying H ₂ O gas and pyridine gas to the wafer 200, that is, the gas supply time (irradiation time) is, for example, 1 to 100 seconds, preferably 5 to 60 seconds. The temperature of the heater 207 is such that the temperature of the wafer 200 is similar to the temperature of the wafer 200 in step 1a, for example, room temperature to 150 ° C., preferably room temperature to 100 ° C., more preferably 50 ° C. to 100 ° C. Set the temperature within the range of.

The H ₂ O gas supplied into the processing chamber 201 is activated by heat and exhausted from the exhaust pipe 231. At this time, H ₂ O gas activated by heat is supplied to the wafer 200. The gas flowing into the processing chamber 201 is a thermally activated H ₂ O gas, and no BTCSM gas is flowing into the processing chamber 201. Therefore, the H ₂ O gas does not cause a gas phase reaction, is supplied to the wafer 200 in an activated state, and includes the first layer (including C and Cl) formed on the wafer 200 in Step 1a. Reacts with at least part of the Si-containing layer). As a result, the first layer is thermally oxidized by non-plasma and is changed into a second layer containing Si, O, and C, that is, a SiOC layer.

Pyridine gas weakens the bonding force of O-H bond the H 2 _O gas has, promote decomposition of the H 2 _O gas, acts as a catalyst gas for promoting the reaction between the H 2 _O gas and the first layer. For example, as shown in FIG. 5B, the pyridine gas acts on the O—H bond of the H ₂ O gas and weakens the bonding force between O—H. By reacting H having weak bonding force with Cl contained in the first layer formed on the wafer 200, a gaseous substance containing Cl and H such as HCl is generated, and H ₂ O molecules generate H Desorbs and Cl desorbs from the first layer. O in the H ₂ O gas that has lost H is bonded to Si in the first layer in which Cl is desorbed and at least a part of C remains.

In the step of supplying H ₂ O gas in a state where pyridine gas is supplied (step of supplying H ₂ O gas and pyridine gas), the supply amount of pyridine gas to be supplied is set according to the desired film composition and the like. It can be adjusted appropriately. When the supply amount of pyridine gas is increased, the action of pyridine gas is enhanced, the oxidizing power of H ₂ O gas is improved, the Si—C bond is broken, and C is easily desorbed. As a result, C in the SiOC layer The concentration decreases. When the supply amount of pyridine gas is lowered, the action of pyridine gas is weakened, the oxidizing power of H ₂ O gas is lowered, Si—C bonds are easily maintained, and as a result, the C concentration in the SiOC layer is increased. Therefore, by appropriately adjusting the supply amount of pyridine gas, the C concentration, Si concentration, O concentration, etc. in the SiOC layer, that is, in the SiOC film in which the SiOC layer is laminated, are relatively changed. Can do.

The supply amount of pyridine gas to be supplied in the step of supplying H ₂ O gas in the state of supplying pyridine gas (step of supplying H ₂ O gas and pyridine gas) is the same as that of the above-mentioned pyridine gas. The supply amount of pyridine gas supplied in the step of supplying BTCSM gas in the state (step of supplying BTCSM gas and pyridine gas) can be adjusted independently. For example, the supply amount of pyridine gas in both steps may be adjusted to be the same or different.

  By preparing in advance a plurality of process recipes (programs describing processing procedures and processing conditions) in which the supply amount and flow rate of pyridine gas are set to different values, adjustment of the supply amount of pyridine gas is facilitated. An operator (operator) may select an appropriate process recipe as appropriate in accordance with a desired film composition or the like and execute a film forming process.

When the SiOC layer is formed under a low temperature condition of, for example, 150 ° C. or less as in the present embodiment, impurities (first impurities) such as moisture (H ₂ O) and Cl, hydrocarbon compounds, and the like are included in the SiOC layer. Hydrocarbon (C _x H _y ) -based impurities (second impurities) are likely to be mixed. That is, the SiOC film formed by laminating this SiOC layer may contain a large amount of impurities such as moisture and Cl and C _x H _y- based impurities. Impurities such as moisture are derived from, for example, H ₂ O gas used as an oxidizing gas or moisture brought in from the outside when the wafer 200 is carried into the processing chamber 201. Impurities such as Cl are derived from, for example, Cl in the BTCSM molecule. C _x H _y- based impurities are derived from, for example, C and H in the BTCSM molecule and C and H in the pyridine molecule.

(Residual gas removal)
Thereafter, the valve 243b is closed and the supply of H ₂ O gas is stopped. Further, the valve 243c is closed and the supply of pyridine gas is stopped. At this time, while the APC valve 244 is kept open, the inside of the processing chamber 201 is evacuated by the vacuum pump 246, and the H ₂ O gas, pyridine gas, and reaction remaining in the processing chamber 201 or contributed to the reaction remain. By-products are removed from the processing chamber 201. Further, the supply of N ₂ gas into the processing chamber 201 is maintained while the valves 243j to 243l remain open. The N ₂ gas acts as a purge gas, and thereby, H ₂ O gas, pyridine gas, and reaction byproducts remaining in the processing chamber 201 and contribute to the formation of the second layer are transferred into the processing chamber 201. The effect which excludes from can be heightened.

At this time, the gas remaining in the processing chamber 201 may not be completely removed, and the inside of the processing chamber 201 may not be completely purged. If the amount of gas remaining in the processing chamber 201 is very small, no adverse effect will occur in the subsequent step 1a. The flow rate of the N ₂ gas supplied into the processing chamber 201 does not need to be a large flow rate. For example, by supplying an amount similar to the volume of the reaction tube 203 (processing chamber 201), an adverse effect occurs in step 1a. There can be no purging. Thus, by not completely purging the inside of the processing chamber 201, the purge time can be shortened and the throughput can be improved. It is also possible to minimize the consumption of N ₂ gas.

As the oxidizing gas, in addition to H ₂ O gas, for example, hydrogen peroxide (H ₂ O ₂ ) gas, hydrogen (H ₂ ) gas + oxygen (O ₂ ) gas, H ₂ gas + ozone (O ₃ ) gas, etc. Can be used. Further, a gas not containing H, for example, O ₂ gas can be used alone. As the catalyst gas, for example, the above-mentioned various amine-based gases and non-amine-based gases can be used in addition to the pyridine gas. As the inert gas, for example, the above-described various rare gases can be used in addition to the N ₂ gas.

  According to the present inventors, it is considered that pyridine gas is more preferable as the catalyst gas throughout each step when comprehensively determined within the gas system and condition range of the present embodiment. TEA gas is then preferred, followed by piperidine gas.

(Performed times)
By setting the above-described steps 1a and 2a as one cycle and performing this cycle one or more times, that is, a predetermined number of times (n times), a SiOC film having a predetermined composition and a predetermined film thickness can be formed on the wafer 200. it can. The above cycle is preferably repeated multiple times. That is, it is preferable that the thickness of the SiOC layer formed per cycle is made smaller than the desired film thickness and the above-described cycle is repeated a plurality of times until the desired film thickness is obtained.

  At this time, by controlling the processing conditions such as the pressure in the processing chamber 201 and the gas supply time in each step, the ratio of each element component in the SiOC layer, that is, Si component, O component and C component, that is, Si concentration The O concentration and the C concentration can be finely adjusted, and the composition ratio of the SiOC film can be controlled more precisely.

  In the case where the cycle is performed a plurality of times, at least in each step after the second cycle, the portion described as “supplying a predetermined gas to the wafer 200” is “to the layer formed on the wafer 200, That is, it means that a predetermined gas is supplied to the outermost surface of the wafer 200 as a laminated body, and a portion described as “form a predetermined layer on the wafer 200” is “formed on the wafer 200”. It means that a predetermined layer is formed on the applied layer, that is, on the outermost surface of the wafer 200 as a laminate. This point is as described above. This also applies to other embodiments described later.

(SiOC film modification process)
As described above, impurities such as moisture and Cl, and C _x H _y impurities may be mixed in the SiOC film formed under a low temperature condition of 150 ° C. or lower, for example. When these impurities are mixed in the SiOC film, the etching resistance of the SiOC film is lowered, and the dielectric constant may be increased. That is, the effect of adding C in the film may be impaired.

Therefore, in this embodiment,
A step of removing first impurities (impurities such as moisture and Cl) from the SiOC film by heat-treating the SiOC film at a first temperature higher than the temperature of the wafer 200 in the step of forming the SiOC film (first Heat treatment step), and
By heat-treating the SiOC film at a second temperature that is equal to or higher than the first temperature, a second impurity (C _x H _y system different from the first impurity) from the SiOC film that has been heat-treated at the first temperature. A step (second heat treatment step),
Then, a modification process for removing a plurality of types of impurities in the SiOC film in at least two stages is performed. That is, a process for modifying the SiOC film, a so-called annealing process is performed in two stages. Hereinafter, a sequence example of the SiOC film modification step will be described.

(Pressure adjustment and temperature adjustment)
The inside of the processing chamber 201 is evacuated by the vacuum pump 246 while feedback controlling the APC valve 244 so that the pressure in the processing chamber 201, that is, the pressure in the space where the wafer 200 exists becomes a desired pressure (degree of vacuum). . Further, the wafer 200 in the processing chamber 201 is heated by the heater 207 so as to reach a desired temperature, that is, the first temperature. At this time, the power supply to the heater 207 is feedback-controlled based on the temperature information detected by the temperature sensor 263 so that the inside of the processing chamber 201 has a desired temperature distribution. Also in this step, the rotation of the boat 217 and the wafers 200 by the rotation mechanism 267 is continued.

At this time, N ₂ gas as an oxygen-free gas is supplied into the processing chamber 201 to make the inside of the processing chamber 201 an oxygen-free atmosphere. At this time, N ₂ gas can be supplied using at least one or all of the gas supply pipes 232j to 232l. Here, for example, N ₂ gas is supplied from all of the gas supply pipes 232j to 232l. That is, the valves 243j to 243l are opened, and N ₂ gas is allowed to flow into the gas supply pipes 232j to 232l. The flow rate of the N ₂ gas is adjusted by the MFCs 241j to 241l, supplied from the gas supply holes 250a, 250c, and 250d into the processing chamber 201, and exhausted from the exhaust pipe 231. Thereby, the inside of the processing chamber 201 becomes an N ₂ gas atmosphere, that is, an oxygen-free atmosphere. Thereafter, the N ₂ gas also acts as a heat treatment gas.

(First heat treatment)
When the inside of the processing chamber 201 becomes an N ₂ gas atmosphere having a desired pressure and the temperature of the wafer 200 reaches a desired temperature, that is, the first temperature, this state is maintained for a predetermined time and formed on the wafer 200. A first heat treatment is performed on the formed SiOC film.

At this time, the APC valve 244 is appropriately adjusted so that the pressure in the processing chamber 201 is, for example, 133 to 101325 Pa (1 to 760 Torr), preferably 10132 to 101325 Pa (76 to 760 Torr). The supply flow rate of the N ₂ gas controlled by the MFCs 241j to 241l is, for example, a flow rate in the range of 100 to 10000 sccm. The heat treatment time for the SiOC film on the wafer 200 is, for example, 1-60 minutes, preferably 1-30 minutes, more preferably 1-10 minutes.

  At this time, the temperature of the heater 207 is set to a temperature at which the temperature of the wafer 200 becomes, for example, a first temperature higher than the temperature of the wafer 200 in the step of forming the above-described SiOC film. Specifically, the temperature of the wafer 200 is higher than room temperature to 150 ° C., for example, 300 ° C. or higher and 450 ° C. or lower, preferably 300 ° C. or higher and 400 ° C. or lower, more preferably 300 ° C. or higher and 350 ° C. or lower. Set the temperature so that the temperature is within the range. In such a temperature range, impurities such as moisture and Cl as the first impurity are efficiently and sufficiently desorbed from the SiOC film without causing undesired reactions (such as oxidation of the SiOC film). It is determined in consideration of removal.

FIG. 12 shows the TDS of the SiOC film before heat treatment formed by the film forming sequence of this embodiment.
Is a diagram illustrating the desorption spectrum by (Atsushi Nobori spectroscopy), (a) is moisture desorption spectrum _{(H 2 O), (b} ) is a desorption spectrum of Cl, (c) Exemplifies C ₂ H ₂ desorption spectra, respectively. 12A to 12C, the horizontal axis represents the temperature (° C.) of the wafer 200 during heat treatment, and the vertical axis represents the ion current value (A).

  As illustrated in FIGS. 12A and 12B, when the temperature of the wafer 200 falls below 300 ° C., impurities such as moisture and Cl, particularly moisture, are removed from the SiOC film and removed. Becomes difficult, and the modification effect of the SiOC film is lowered. For example, when the temperature of the wafer 200 is set to 150 ° C. or less, impurities such as moisture and Cl are hardly desorbed from the SiOC film. By setting the temperature of the wafer 200 to 300 ° C. or higher, impurities such as moisture and Cl can be sufficiently desorbed and removed from the SiOC film.

  However, when the temperature of the wafer 200 exceeds 450 ° C., when moisture, Cl, or the like is desorbed from the SiOC film, the SiOC film may be oxidized due to a reaction between moisture and Cl. As the SiOC film is oxidized, the shrinkage rate of the SiOC film increases.

Further, in this temperature zone, that is, a temperature zone exceeding 450 ° C., HCl is generated when moisture reacts with Cl, and this HCl causes Si—Cl bonds, Si—H bonds, etc. contained in the SiOC film. May be cut off. When these bonds are disconnected, an unnecessary adsorption site is generated in the SiOC film, and a substance (desorbed substance) desorbed from the SiOC film is re-adsorbed to the adsorption site. That is, the desorbed material from the SiOC film is adsorbed to Si that has been broken from the bond with Cl or H and has dangling bonds (unbonded hands). The bond between Si thus formed and the desorbed material is unstable and weak. Therefore, this desorbed substance does not become a component constituting the SiOC film but remains in the SiOC film as an impurity. Examples of the desorbing substance include moisture, Cl and C _x H _y impurities, and substances obtained by decomposing them.

Further, in this temperature range, that is, a temperature range higher than 450 ° C., as illustrated in FIG. 12C, C _x H _y- based impurities are also desorbed from the SiOC film. The desorbed C _x H _y impurities may react with Cl when passing through the SiOC film, thereby causing re-adsorption of C to the adsorption site in the SiOC film. That _is, adsorption by reaction with C x _{H y} based impurities and Cl _of, C derived from the C x _{H y} type impurities of, any of the elements constituting the SiOC film (atomic), for example, dangling bonds of Si There are things to do. The bond between C and Si thus formed is unstable and weak. Therefore, C derived from the C _x H _y- based impurities does not become a component constituting the SiOC film but remains in the SiOC film as an impurity. When C is re-adsorbed to the adsorption site in the SiOC film, C may be re-adsorbed to this adsorption site by itself, or C may be re-adsorbed to this adsorption site in the form of C _x H _y. is there.

  That is, in this temperature range, that is, a temperature range higher than 450 ° C., the film shrinkage rate of the SiOC film increases due to the above-mentioned undesired reaction, and impurities can be sufficiently desorbed and removed from the SiOC film. become unable. As a result, the dielectric constant (k value) of the SiOC film cannot be lowered sufficiently.

By setting the temperature of the wafer 200 to 300 ° C. or more and 450 ° C. or less, impurities such as moisture and Cl can be sufficiently desorbed and removed from the SiOC film while suppressing the above-mentioned unwanted reaction. . That is, when moisture, Cl, etc. are desorbed from the SiOC film, it is possible to suppress oxidation of the SiOC film due to the reaction between moisture and Cl, and to suppress an increase in the film shrinkage rate of the SiOC film. In addition, it is possible to suppress the generation of HCl due to the reaction between moisture and Cl, and to suppress the separation of Si—Cl bonds, Si—H bonds, and the like in the SiOC film due to HCl. As a result, generation of unnecessary adsorption sites in the SiOC film can be suppressed, and resorption of the desorbed substance on the adsorption sites can be suppressed. Also, when C _x H _y impurities are desorbed from the SiOC film, the reaction between the C _x H _y impurities and Cl is suppressed, and the re-adsorption of C to the adsorption site in the SiOC film is suppressed. It becomes possible to do. Further, as shown in FIG. 12C, when the temperature of the wafer 200 is about 400 ° C., the amount of C _x H _y -based impurities desorbed peaks. Therefore, desorption of C _x H _y impurities can be suppressed by setting the temperature of the wafer 200 to 400 ° C. or lower, preferably 350 ° C. or lower. That is, the amount of C _x H _y- based impurities desorbed can be reduced. As a result, the absolute amount of C _x H _y impurities desorbed from the SiOC film can be reduced, and resorption of C due to the reaction between the C _x H _y impurities and Cl can be further suppressed. It becomes.

By setting the temperature of the wafer 200 to such a temperature range, that is, a temperature range of 300 ° C. or more and 450 ° C. or less, the shrinkage rate of the SiOC film can be reduced, and C and C desorbed from the SiOC film can be reduced. _x H _y can be suppressed re-adsorption to the adsorption sites in the SiOC film desorption substances containing impurities from the SiOC film, in particular, it is removed by sufficiently desorbed impurities such as moisture and Cl Is possible.

Further, by setting the temperature of the wafer 200 to such a temperature range, that is, a temperature range of 300 ° C. to 450 ° C., impurities such as moisture and Cl are desorbed and removed from the SiOC film as described above. In addition, at least a part of the C _x H _y impurities is also removed and removed. At that time, if such a temperature range, to suppress the reaction between the impurity and the Cl of C _x H _y system desorbed from the SiOC film, re-adsorption of C to the adsorption site in the SiOC film Can be suppressed. That is, by setting such a temperature zone, it is possible to suppress re-adsorption of C in the C _x H _y- based impurities once desorbed from the SiOC film to the adsorption site in the SiOC film. Become.

  From the above, the temperature of the wafer 200 is set to a temperature in the range of 300 ° C. to 450 ° C., preferably 300 ° C. to 400 ° C., more preferably 300 ° C. to 350 ° C.

By applying the first heat treatment to the SiOC film under the above-described conditions, impurities such as moisture and Cl in the SiOC film are sufficiently desorbed from the SiOC film while suppressing the above-described unwanted reaction. Can be removed. Further, at least a part of the C _x H _y- based impurities in the SiOC film can be desorbed and removed from the SiOC film while suppressing the undesired reaction described above. Since these impurities in the SiOC film are removed from the SiOC film, the SiOC film is modified, and the etching resistance of the SiOC film is higher than that of the SiOC film before the first heat treatment, and the dielectric constant is increased. The film quality (film characteristics) of the SiOC film can be improved.

However, when the first heat treatment step is completed, that is, when impurities such as moisture and Cl are sufficiently removed from the SiOC film, C _x H _y- based impurities remain in the SiOC film. There is. That is, in this temperature range, the impurity of the impurity and C _x H _y system of water and Cl, etc. from the SiOC film is removed by elimination found the following impurities such as moisture and Cl, C _x H _y Since most of impurities such as moisture and Cl are removed, the C _x H _y impurities may still remain in the SiOC film because the impurities are removed before the impurities. At this stage, the k value of the SiOC film may not be sufficiently lowered due to C _x H _y- based impurities remaining in the SiOC film. Therefore, in the second heat treatment step to be described later, the SiOC film is heat-treated at a second temperature equal to or higher than the first temperature, so that the SiOC film remains in the SiOC film after the heat treatment at the first temperature. The C _x H _y- based impurities are removed. As a result, the k value of the SiOC film can be sufficiently reduced.

(Second heat treatment)
After the first heat treatment is completed, that is, after impurities such as moisture and Cl are sufficiently desorbed and removed from the SiOC film, the temperature of the wafer 200 is changed from the first temperature to the second temperature. The second temperature is equal to or higher than the first temperature. That is, the second temperature is set to a temperature higher than the first temperature or a temperature equivalent to the first temperature. The atmosphere in the processing chamber 201 is maintained in an N ₂ gas atmosphere having a desired pressure similar to that in the first heat treatment step.

  When the temperature of the wafer 200 reaches a desired temperature, that is, the second temperature, this state is maintained for a predetermined time, and the second heat treatment is performed on the SiOC film on which the first heat treatment has been performed. That is, the second heat treatment is performed at the second temperature on the SiOC film that has been subjected to the first heat treatment at the first temperature.

At this time, the APC valve 244 is appropriately adjusted so that the pressure in the processing chamber 201 is, for example, 133 to 101325 Pa (1 to 760 Torr), preferably 10132 to 101325 Pa (76 to 760 Torr). The supply flow rate of the N ₂ gas controlled by the MFCs 241j to 241l is, for example, a flow rate in the range of 100 to 10000 sccm. The heat treatment time for the SiOC film on the wafer 200 is, for example, 1 to 120 minutes, preferably 1 to 60 minutes, more preferably 1 to 30 minutes.

At this time, the temperature of the heater 207 is set to a temperature at which the temperature of the wafer 200 becomes, for example, a second temperature that is equal to or higher than the first temperature in the first heat treatment step described above. Specifically, the temperature of the wafer 200 is equal to or higher than the first temperature, and is, for example, 300 ° C. or higher and 900 ° C. or lower, preferably 350 ° C. or higher and 700 ° C. or lower, more preferably 400 ° C. or higher and 700 ° C. or lower. More preferably, the temperature is set to a temperature in the range of 450 ° C. to 600 ° C. In such a temperature range, the C _x H _y- based impurities as the second impurities can be efficiently and sufficiently desorbed and removed from the SiOC film, and the thermal load and thermal history applied to the wafer 200 can be reduced. Determined in consideration of the above.

As illustrated in FIG. 12C, when the temperature of the wafer 200 is lower than 300 ° C., it is difficult to desorb and remove C _x H _y- based impurities such as C ₂ H ₂ from the SiOC film. As a result, the modification effect of the SiOC film is lowered. For example, when the temperature of the wafer 200 is set to 200 ° C. or lower, C _x H _y impurities are hardly desorbed from the SiOC film. By setting the temperature of the wafer 200 to 300 ° C. or higher, it is possible to sufficiently remove and remove C _x H _y impurities from the SiOC film. However, when the temperature of the wafer 200 is 300 ° C., it may take time to sufficiently desorb C _x H _y impurities from the SiOC film. By setting the temperature of the wafer 200 to 350 ° C. or higher, it is possible to shorten the time until the C _x H _y- based impurities are sufficiently desorbed from the SiOC film. In particular, when the temperature of the wafer 200 is about 400 ° C., the amount of C _x H _y -based impurities desorbed peaks. Therefore, by setting the temperature of the wafer 200 to 400 ° C. or higher, it is possible to promote desorption of C _x H _y- based impurities. In other words, C _x H _y impurities can be efficiently desorbed from the SiOC film. Further, it is possible to further shorten the time from the SiOC film until the fully desorb C _x H _y based impurities.

At the stage of performing the second heat treatment step, impurities such as moisture and Cl in the SiOC film have already been removed, and the above-mentioned unwanted reaction does not occur. That is, the oxidation of the SiOC film due to the reaction between moisture and Cl, the increase in the shrinkage rate of the SiOC film due to the reaction, the generation of HCl due to the reaction between the moisture and Cl, the Si—Cl bond and Si—H in the SiOC film due to HCl. Separation of bonds, etc., generation of unnecessary adsorption sites, resorption of desorbed substances on the adsorption sites, resorption of C on adsorption sites by reaction of C _x H _y impurities and Cl, etc. No reaction will occur. This is because the second temperature includes a temperature zone in which an undesired reaction can occur (temperature zone exceeding 450 ° C.), but in the stage of performing the second heat treatment step, a substance (moisture or Cl Etc.) does not occur. Note that it is also preferable that the temperature of the wafer 200 be 450 ° C. or higher because it is possible to promote desorption of C _x H _y impurities from the SiOC film. By setting the temperature of the wafer 200 to 450 ° C. or higher, the desorption of C _x H _y- based impurities from the SiOC film can be promoted more than when the temperature of the wafer 200 is set to 300 to 350 ° C.

  When the temperature of the wafer 200 exceeds 900 ° C., the heat load becomes too large, and the electrical characteristics of the semiconductor device formed on the wafer 200 may be affected. By setting the temperature of the wafer 200 to at least 900 ° C. or less, it is possible to suppress the influence of the thermal load on the electrical characteristics and the like. When the wafer 200 on which the SiOC film to be heat-treated is intended for a memory device, it can withstand heat of about 900 ° C. Even if the wafer 200 is for a logic device, it can withstand heat of about 700 ° C. If the temperature of the wafer 200 is set to 600 ° C. or lower, it becomes easy to more reliably avoid thermal damage such as a device structure.

  From the above, the temperature of the wafer 200 is 300 ° C. or higher and 900 ° C. or lower, preferably 350 ° C. or higher and 700 ° C. or lower, more preferably 400 ° C. or higher and 700 ° C. or lower, more preferably 450 ° C. or higher and 600 ° C. or lower. It is good to do. The second temperature may be a temperature equal to or higher than the first temperature. That is, the second temperature may be higher than the first temperature, or may be equivalent to the first temperature.

For example, when the first temperature is set to 300 to 400 ° C. and the second temperature is set to 450 to 600 ° C., the undesired reaction described above is surely prevented in each of the first heat treatment step and the second heat treatment step. It becomes possible to do. In particular, by setting the first temperature to 300 to 400 ° C., it is possible to more reliably prevent an undesired reaction in the first heat treatment step. In addition, even if the second temperature is 450 to 600 ° C., that is, a temperature zone in which an undesired reaction may occur, substances (moisture, Cl, etc.) that cause an undesired reaction are generated at the stage of performing the second heat treatment step. Therefore, it is possible to reliably suppress an undesired reaction. Further, by setting the second temperature to 450 to 600 ° C., that is, a temperature exceeding the first temperature, the desorption of C _x H _y- based impurities from the SiOC film in the second heat treatment step is further improved. This can be done quickly.

  Further, for example, the first temperature and the second temperature may be the same temperature, for example, the same temperature within a range of 400 to 450 ° C. If the first temperature and the second temperature are set to the same temperature within the range of 400 to 450 ° C., the undesired reaction described above can be reliably suppressed in the first heat treatment step and the second heat treatment step. Is possible. Further, if the first temperature and the second temperature are the same, the temperature of the wafer 200, that is, the temperature in the processing chamber 201 (heater) between the first heat treatment step and the second heat treatment step. It is not necessary to change (adjust) the temperature 207. That is, it is not necessary to wait between the first heat treatment step and the second heat treatment step until the temperature in the processing chamber 201 is stabilized. Therefore, these steps can be performed continuously, and the temperature control of the heat treatment can be simplified.

By performing the second heat treatment on the SiOC film under the above-described conditions, the C _x H _y- based impurities in the SiOC film are sufficiently desorbed from the SiOC film while suppressing the above-described unwanted reaction. Can be removed. By removing the impurities in the SiOC film from the SiOC film, the SiOC film is further modified, and after the first heat treatment, the SiOC film is more than the SiOC film before the second heat treatment is performed. The etching resistance can be further increased, and the dielectric constant can be further reduced. That is, the film quality (film characteristics) of the SiOC film can be further improved. According to the method of the present embodiment, the dielectric constant (k value) of the SiOC film can be reduced to about 2.7, for example.

As described above, in this embodiment, first, the SiOC film is heat-treated in a temperature zone (first temperature) at which an undesired reaction does not occur. As a result, impurities (first impurities) such as moisture and Cl, which are substances that cause an undesired reaction, are removed from the SiOC film without causing an undesired reaction. Then, after removing impurities (first impurities) such as moisture and Cl, which are substances that cause an undesired reaction, from the SiOC film, a temperature range (second temperature) including a temperature range in which an undesired reaction may occur. Then, the SiOC film is heat-treated in an atmosphere in which impurities (first impurities) such as moisture and Cl, which are substances that cause undesired reactions, are not present (generated). As a result, the C _x H _y- based impurities (second impurities) are removed from the SiOC film after the heat treatment in the temperature zone (first temperature) at which no unwanted reactions occur without causing undesired reactions. Like to do.

  Such heat treatment in this embodiment can also be referred to as two-stage heat treatment (multi-stage heat treatment). It can also be called two-stage annealing (multi-stage annealing), two-stage modification treatment (multi-stage modification treatment), two-stage impurity removal treatment (multi-stage impurity removal treatment), or the like.

In the first heat treatment step and the second heat treatment step, the inside of the processing chamber 201 is made an oxygen-free atmosphere with N ₂ gas as an oxygen-free gas. The oxygen-free atmosphere here is not only the state in which no oxidizing gas (O component) is present in the atmosphere in the processing chamber 201 but also the concentration of the oxidizing gas (O concentration) in the atmosphere in the processing chamber 201. In addition, the state includes a state in which the SiOC film to be processed is lowered to such an extent that the film is not affected. As a result, even if heat treatment is performed at a temperature higher than the film formation temperature as described above, the O concentration in the SiOC film increases beyond the desired concentration, that is, the oxidation of the SiOC film proceeds excessively. Can be suppressed. In addition, since the inside of the processing chamber 201 is an oxygen-free atmosphere, the C concentration in the SiOC film decreases below the desired concentration as the oxidation progresses, that is, C is desorbed from the SiOC film. It can suppress separating. At this time, it can be said that the oxygen-free gas such as N ₂ gas acts as a heat treatment gas. It can also be said that N ₂ gas or the like acts as a carrier gas for carrying impurities desorbed from the SiOC film. That is, it can be said that the oxygen-free gas acts as an annealing gas that promotes the discharge of these impurities from the SiOC film or the processing chamber 201 and thereby promotes the modification of the SiOC film.

In order to make the inside of the processing chamber 201 an oxygen-free atmosphere, for example, as an atmosphere generation unit that generates an oxygen-free atmosphere without supplying an oxygen-free gas such as N ₂ gas to the wafer 200. The inside of the processing chamber 201 may be evacuated by an exhaust system. Thereby, most components including the O component can be exhausted and removed from the atmosphere in the processing chamber 201. However, as described above, exhausting the inside of the processing chamber 201 and further supplying an oxygen-free gas such as N ₂ gas to the wafer 200 facilitates exhaust of the O component remaining in the processing chamber 201. Thus, it becomes easy to make the inside of the processing chamber 201 an oxygen-free atmosphere. Further, even if outgas containing an O component is generated from the inner wall of the processing container constituting the processing chamber 201, the wafer 200 brought in from the outside, or the like in this direction, due to the dilution effect by the N ₂ gas, the inside of the processing chamber 201 It is easy to maintain an oxygen-free atmosphere.

  The modification process (annealing process) of the SiOC film is mainly performed during a heat treatment period in which the temperature of the wafer 200 is stably maintained at a desired temperature. However, when the temperature of the wafer 200 is raised in the above-described step of adjusting the temperature of the wafer 200 (step of changing from the film formation temperature to the first temperature, step of changing from the first temperature to the second temperature, etc.) Alternatively, even when the temperature of the wafer 200 is lowered in the process of purging the inside of the processing chamber 201 described later, while the temperature of the wafer 200 is maintained at a temperature at which the removal of impurities in the SiOC film can proceed. The SiOC film modification process can proceed. Therefore, the step of modifying the SiOC film mainly refers to a step of heat-treating the SiOC film, but at least a part of the step of adjusting the temperature of the wafer 200 and the step of purging the inside of the processing chamber 201. The period may be included in the process of modifying the SiOC film. In other words, the step of modifying the SiOC film refers to a period from when the temperature of the wafer 200 reaches a temperature necessary for the reforming process to immediately before reaching a temperature lower than the temperature necessary for the reforming process. It can be said. The step of modifying the SiOC film refers to the step of modifying the SiOC film after the temperature of the wafer 200 reaches the temperature necessary for the modification process, that is, after the modification of the SiOC film is started. It can also be said to indicate the period until completion.

As the oxygen-free gas, in addition to N ₂ gas, for example, a rare gas such as Ar gas, He gas, Ne gas, or Xe gas can be used.

(Purge and return to atmospheric pressure)
When the process of modifying the SiOC film is completed, the valves 243j to 243l are kept open, N ₂ gas is supplied from the gas supply pipes 232j to 232l into the processing chamber 201, and the exhaust pipe 231 is exhausted. The N ₂ gas acts as a purge gas, whereby the inside of the processing chamber 201 is purged, and the gas remaining in the processing chamber 201 and the gas containing impurities such as impurities desorbed from the SiOC film are removed from the processing chamber 201. Is done. Thereafter, the atmosphere in the processing chamber 201 is replaced with an inert gas, and the pressure in the processing chamber 201 is returned to normal pressure.

  In addition, the temperature of the wafer 200 is adjusted so that the temperature of the wafer 200 is, for example, less than 200 ° C., preferably about room temperature, by adjusting the power supply to the heater 207 or stopping the power supply to the heater 207. Let the temperature drop. By lowering the temperature of the wafer 200 in parallel with the above-described purge and return to atmospheric pressure, the temperature of the wafer 200 can be lowered to a predetermined temperature in a short time due to the cooling effect of the purge gas.

(Boat unload and wafer discharge)
Thereafter, the seal cap 219 is lowered by the boat elevator 115, the lower end of the manifold 209 is opened, and the processed wafer 200 is carried out from the lower end of the manifold 209 to the outside of the reaction tube 203 while being supported by the boat 217 (boat unloading). Loaded). The processed wafer 200 is taken out from the boat 217 (wafer discharge).

(3) Effect by this embodiment According to this embodiment, the following one or more effects are exhibited.

(A) By supplying a catalyst such as pyridine gas together with a raw material containing Si, C and halogen elements such as BTCSM gas and having a Si—C bond, it is possible to promote decomposition of the raw material such as BTCSM gas. Become. Thereby, for example, the first layer can be formed even under a low temperature condition of 150 ° C. or lower. Further, when forming the first layer, it is possible to make the formation of the chemical adsorption layer, not the physical adsorption layer of the raw material such as BTCSM gas, dominant, and the formation rate of the first layer can be increased. It becomes.

Further, by supplying the catalyst such as pyridine gas with oxidizing agents such as the H 2 _O gas, encourage the decomposition of the oxidizing agent such as the H 2 _O gas, the oxidizing power of the oxidizing agent such as the H 2 _O gas Can be improved. Thereby, for example, even under a low temperature condition of 150 ° C. or lower, the first layer and an oxidizing agent such as H ₂ O gas are efficiently reacted to reform the first layer into the second layer. It becomes possible. In addition, the modification rate of the first layer can be increased.

  In other words, the catalytic action of a catalyst such as pyridine gas can lower the deposition temperature of the SiOC film and increase the deposition rate of the SiOC film.

(B) By using a source gas containing Si, C, and a halogen element and having a Si—C bond, such as a BTCSM gas, that is, a gas that acts as a Si source and acts as a C source, C can be added to the layer. As a result, it is possible to form a film to which C is added at a high concentration, that is, a SiOC film having a high C concentration.

  In particular, it is possible to increase the C concentration in the SiOC film by using a raw material gas having Si—C—Si bonds that do not have Si—Si bonds and in which C intervenes between them, such as BTCSM gas. It becomes possible. This is because C contained in the source gas is bonded to Si by two bonds. For this reason, when the first layer is formed, it is possible to suppress that all the bonds between C and Si contained in the BTCSM gas are broken and C is not taken into the first layer. Further, when the first layer is modified to the second layer, all the bonds between C and Si contained in the first layer are broken, and C is desorbed from the first layer. Can be suppressed. That is, by using a source gas having a Si—C—Si bond such as BTCSM gas, compared to using a source gas or the like that does not have a bond in which C intervenes between Si—Si, such as TCMDDS gas. It becomes possible to increase the C concentration in the film.

  Further, by adding C to the film, it is possible to improve the resistance (etching resistance) of the SiOC film to hydrofluoric acid (HF).

For reference, the wet etching rate (hereinafter also referred to as WER) for 1% concentration hydrofluoric acid (1% HF aqueous solution) is about 600 Å / min for a SiO film obtained by using a catalyst gas under a low temperature condition. The SiO film obtained by using plasma below is about 200 Å / min, and the thermal oxide film obtained by thermally oxidizing a silicon wafer in an oxidation furnace is about 60 Å / min. That is, an SiO film formed using a catalyst gas or plasma under a low temperature condition tends to have a lower etching resistance than a thermal oxide film. In order to improve the etching resistance, it is effective to add C to the film, that is, to form a SiOC film. When the film forming temperature is 600 to 800 ° C., for example, a raw material gas (Si source) such as HCDS gas, an oxidizing gas (O source) such as O ₂ gas, or a carbon-containing gas such as propylene (C ₃ H ₆ ) gas. By alternately or simultaneously supplying (C source) to the wafer, it is possible to form a SiOC film. However, when the film forming temperature is set to 150 ° C. or lower, for example, it is difficult to form the SiOC film using the above gas or the above film forming method.

  On the other hand, in the present embodiment, it is possible to form a SiOC film to which C is added at a high concentration, that is, a film having high etching resistance, even under a low temperature condition of, for example, 150 ° C. or less. For example, in the present embodiment, a film having higher etching resistance than the thermal oxide film can be formed. Further, the C concentration in the SiOC film, that is, the etching resistance can be accurately controlled by appropriately adjusting the supply amount of pyridine gas.

(C) By using an alkylenehalosilane source gas having a small molecular weight (molecular size) of an alkylene group contained in one molecule, such as BTCSM gas, it is possible to increase the film formation rate and form a strong film. It becomes. This is because, for example, when an alkylene halosilane source gas containing a high molecular weight alkylene group such as a hexylene group or a heptylene group in one molecule is used, this high molecular weight alkylene group reacts with Si contained in the raw material gas. It may cause steric hindrance to inhibit and inhibit the formation of the first layer. In addition, when the above-described alkylene group remains undecomposed or only partially decomposed in the first layer, this large molecular weight alkylene group is contained in the Si and H contained in the first layer. _It may cause a steric hindrance that hinders the reaction with ₂ O gas, thereby inhibiting the formation of the second layer. On the other hand, by using an alkylenehalosilane raw material gas having a small molecular weight of an alkylene group contained in one molecule, such as BTCSM gas, the occurrence of the steric hindrance can be suppressed, and the first layer and The formation of the second layer can be promoted. As a result, the film formation rate can be increased and a strong film can be formed. The same effect can be obtained also when an alkylhalosilane source gas having a small molecular weight of an alkyl group contained in one molecule, such as TCMDDS gas, is used.

(D) By using a source gas containing two Si atoms in one molecule such as BTCSM gas, it becomes possible to make the SiOC film a film in which Si contained in the film are close to each other. This is because, when the first layer is formed under the condition that the BTCSM gas does not self-decompose, the two Si contained in the BTCSM gas molecules remain on the wafer 200 (surface underlayer film) while being kept close to each other. Will be adsorbed. Further, when the first layer is formed under a condition in which the BTCSM gas is self-decomposed, the two Si contained in the BTCSM gas molecules are more likely to be deposited on the wafer 200 while maintaining a state in which they are close to each other. That is, by using a gas containing two Si in one molecule such as BTCSM gas, in one molecule such as trisdimethylaminosilane (Si (N (CH ₃ ) ₂ )) ₃ H, abbreviated as 3DMAS) gas. As compared with the case where a gas having only one Si is used, Si contained in the first layer can be brought close to each other. As a result, the SiOC film can be a film in which Si in the film is close to each other. Thereby, the etching resistance of the film can also be improved.

(E) Supplying a raw material such as BTCSM gas and a catalyst such as pyridine gas, and supplying an oxidizing agent such as H ₂ O gas and a catalyst such as pyridine gas, these gases are performed alternately. Can be appropriately reacted under conditions where the surface reaction is dominant. As a result, it is possible to improve the step coverage of the SiOC film and the controllability of film thickness control. In addition, excessive gas phase reaction in the processing chamber 201 can be avoided, and generation of particles can be suppressed.

(F) The first impurity (impurities such as moisture and Cl) can be removed from the SiOC film by heat-treating the SiOC film at a first temperature higher than the deposition temperature of the SiOC film. Thereafter, the SiOC film is heat-treated at a second temperature that is equal to or higher than the first temperature, whereby a second impurity (C _x H different from the first impurity) from the SiOC film after the heat treatment at the first temperature. _y- based impurities) can be removed. As a result, the SiOC film can be made to be a film with less impurities than the as-deposited SiOC film before the SiOC film modification step. Thereby, the etching resistance of the SiOC film can be improved and the dielectric constant of the film can be lowered. That is, the quality of the SiOC film can be improved.

(G) A porous film can be formed by performing a series of processes of the SiOC film forming step and the SiOC film modifying step. That is, the SiOC film can be made porous.

This is because at least Si—C bonds and Si—O bonds exist in the film formed in the SiOC film forming step. The bond distance between Si and C is larger than the bond distance between Si and O. Therefore, compared to the SiO ₂ film, the SiOC film has a larger interatomic distance due to the introduction of Si—C bonds into the film, resulting in a sparse film density. In addition, there may be Si—C—Si bonds in the SiOC film. In this case, the film density is further sparse. In particular, when a gas having Si—C—Si bonds such as BTCSM gas is used as the source gas, the SiOC film tends to contain Si—C—Si bonds, and the film density tends to be sparse. Become. It can be said that a minute hole (pore), that is, a minute space is generated in the portion where the film density is sparse. That is, the SiOC film formed in the SiOC film forming step becomes a porous film in an as-deposited state, that is, a film having a low atomic density in the film.

In addition, in the SiOC film modification process, when impurities such as moisture and Cl or C _x H _y impurities are desorbed from the SiOC film, a minute hole (pore), That is, a minute space is generated. That is, the SiOC film modified by the SiOC film modification step becomes a porous film that is further porous, that is, a film having a lower atomic density than the as-deposited SiOC film. However, if the above-mentioned undesired reaction occurs in the SiOC film modification step, the film shrinkage rate of the SiOC film increases and it becomes difficult to maintain the porous state of the SiOC film. By performing the SiOC film modification step under the above-described processing conditions, it is possible to modify (change) the porous state in a more advanced state while maintaining the porous state in the as-deposited state. That is, the quality of the SiOC film can be improved.

(H) By performing a series of processes of the SiOC film forming step and the SiOC film modifying step, the dielectric constant (k value) of the SiOC film can be made lower than the dielectric constant of the SiO ₂ film. This is because the SiOC film can be made porous as described above by performing a series of processes of the SiOC film forming process and the SiOC film modifying process. Further, by performing the SiOC film modification step, impurities such as moisture and Cl and C _x H _y impurities can be removed from the SiOC film. Impurities such as moisture are substances that change the direction according to the electric field and increase the dielectric constant because they have a permanent dipole moment. By making the SiOC film porous and removing the substance that increases the dielectric constant, the dielectric constant of the SiOC film can be made lower than the dielectric constant of the SiO ₂ film. According to the film forming sequence of the present embodiment, it was confirmed that the dielectric constant of the SiOC film can be lowered to, for example, 3.0 or less, specifically 2.68.

(I) By the way, in a ReRAM or MRAM developed as a transistor or a next generation memory, as a thin film satisfying low temperature film formation, low WER (high etching resistance), low dielectric constant, etc., for example, a silicon nitride film (SiN film) It is conceivable to use a thin film such as a silicon carbonitride film (SiCN film) in which C is added to C), or a silicon oxycarbonitride film (SiOCN film) in which O is further added to the SiCN film. On the other hand, in order to further improve the etching resistance of these thin films and further reduce the dielectric constant, it is necessary to increase the C concentration and O concentration in the film and to decrease the N concentration. However, for example, it is difficult to increase the C concentration and the like while suppressing the N concentration to, for example, the impurity level in the low temperature region by the above-described method of forming films by alternately supplying various gases.

  On the other hand, in the present embodiment, even under a low temperature condition of, for example, 150 ° C. or lower, the source gas containing Si, C and Cl and having a Si—C bond is used to increase the C concentration in the thin film. Or can be controlled with high accuracy.

(4) Modification of this Embodiment The film-forming sequence of this embodiment is not limited to the aspect shown to Fig.4 (a), It can change like the modification shown below.

(Modification 1)
In step 1a for supplying the source gas, an alkylenehalosilane source gas having a different type from the BTCSM gas, such as BTCSE gas, may be supplied as the source gas. Further, for example, an alkylhalosilane source gas such as a TCDMDS gas may be supplied. FIG. 4B shows an example in which TCDMDS gas is used instead of BTCSM gas as the source gas. In this case, in step 1a, the opening / closing control of the valve 243d is performed in the same procedure as the opening / closing control of the valve 243a in step 1a of the film forming sequence shown in FIG. Other processing conditions and processing procedures are the same as the film forming sequence shown in FIG.

  According to this modification, the same effect as the film forming sequence shown in FIG.

  Further, by appropriately selecting the type of source gas as in this modification, it is possible to control the C concentration in the SiOC film. Further, by controlling the C concentration in the SiOC film, it becomes possible to change the Si concentration and the O concentration relative to the C concentration.

  As one factor, for example, a difference in arrangement of C in the molecular structure of each source gas can be considered. This is because BTCSM gas, BTCSE gas, and the like are source gases having Si—C—Si bonds and Si—C—C—Si bonds, and have a molecular structure in which C is sandwiched between Si. Of the four bonds of Si contained in BTCSM gas, BTCSE gas, etc., a lot of Cl is bonded to the remaining bonds that are not bonded to C. For example, both BTCSM gas and BTCSE gas have Cl bonded to three of the four bonds of Si. Thus, since BTCSM gas, BTCSE gas, and the like contain a large amount (for example, 6) of Cl in one molecule, the number of Cl contained in one molecule such as a TCDMDS gas is small (for example, 4). The following) is considered to have higher reactivity than the raw material gas. By using a highly reactive BTCSM gas, BTCSE gas, or the like as a raw material gas, the reaction for forming the first layer can be performed efficiently, and the deposition rate of the SiOC film can be increased. . In addition, by using a highly reactive source gas, it is possible to extend the range of processing conditions in which the film forming process can proceed, that is, the process window. Since the film forming conditions for obtaining a desired C concentration can be selected from within a wide process window, it is easy to increase the C concentration in the SiOC film as a result. In addition, the controllability of the C concentration in the SiOC film can be improved. Here, the number of C contained in the BTCSM gas is smaller than, for example, TCMDDS gas. However, this point is considered not to adversely affect the improvement of the C concentration in the SiOC film. According to the present inventors, it has been confirmed that it is easier to improve the C concentration by using BTCSM gas than by using TCDMDS gas.

  TCMDDS gas, DCTMDS gas, etc. are raw material gases having no Si—C—Si bond or Si—C—C—Si bond, and a molecular structure in which an alkyl group such as a methyl group is bonded to Si, that is, chlorosilane. It has a molecular structure in which part of the chloro group of the source gas is replaced with a methyl group. TCMDDS gas, DCTMDS gas, and the like are considered to be less reactive than source gases such as BTCSM gas and BTCSE gas because the number of Cl contained in one molecule is small (for example, 4 or less). Therefore, by using TCMDDS gas, DCTMDS gas, or the like as a source gas, the reaction at the time of forming the first layer can proceed relatively slowly, and the SiOC film can be made a denser film. It becomes possible. As a result, even if the C concentration in the SiOC film is appropriately suppressed, high etching resistance can be maintained. In comparison between the case where TCMDDS gas is used as the source gas and the case where DCTMDS gas is used as the source gas, the DCTMDS gas containing a large amount of methyl groups, that is, C in one molecule is incorporated into the film. It has been confirmed that it works favorably in quantity.

Thus, by selecting and supplying, for example, BTCSM gas, BTCSE gas, or the like as the source gas, it becomes easy to increase the C concentration in the SiOC film. In addition, by selecting and supplying, for example, TCMDDS gas, DCTMDS gas, or the like as the source gas, it is possible to appropriately suppress the C concentration in the SiOC film while maintaining etching resistance. As described above, by selecting and supplying a specific source gas from a plurality of types of source gases, it is possible to accurately control the C concentration and the like in the SiOC film.

(Modification 2)
In step 2a for supplying the O ₂ gas, a catalyst gas having a molecular structure different from that of the pyridine gas, that is, an amine-based catalyst gas different from the pyridine gas may be supplied as the catalyst gas. That is, the type of catalyst gas supplied together with the raw material gas may be different from the type of catalyst gas supplied together with the oxidizing gas. In this case, in step 2a, an amine catalyst gas of a type different from the pyridine gas may be supplied from the gas supply pipe 232c. Other processing conditions and processing procedures are the same as the film forming sequence shown in FIG.

  According to this modification, the same effect as the film forming sequence shown in FIG.

  Further, by appropriately selecting the type of the catalyst gas as in the present modification, the C concentration in the SiOC film can be controlled. Further, by controlling the C concentration in the SiOC film, the Si concentration and the O concentration in the film can be relatively changed.

  As one factor, for example, a difference in the strength of the catalytic action according to the molecular structure of the catalyst gas can be considered. For example, by selecting a catalyst gas having a large pKa value, decomposition of the oxidizing gas may be promoted and its oxidizing power may increase. As a result, the Si—C bond contained in the first layer is broken in step 2a, and the C concentration in the finally formed SiOC film may be lowered. In addition, for example, by selecting a catalyst gas having a small pKa, decomposition of the oxidizing gas is appropriately suppressed, and its oxidizing power may be reduced. As a result, the Si—C bond contained in the first layer is easily maintained in step 2a, and the C concentration in the finally formed SiOC film may increase. Further, as another factor, a difference in vapor pressure of various substances involved in a catalytic reaction such as a catalyst gas or a generated salt can be considered. In addition, composite factors that combine these factors can be considered.

(Modification 3)
When the above-described steps 1a and 2a are performed a plurality of times, the type of the source gas and the type of the catalyst gas may be changed during the cycle. Moreover, when performing the cycle of step 1a, 2a in multiple times, you may change the supply amount of catalyst gas in the middle.

  In this case, the type of the source gas may be changed only once or a plurality of times. Moreover, the source gas used may be two types or three or more types. The combination of source gases can be arbitrarily selected from source gases containing Si, C and halogen elements and having Si—C bonds. The order in which the source gases are used can be arbitrarily selected. Further, the type of the catalyst gas may be changed only once or a plurality of times. Further, the catalyst gas used may be two types or three or more types. The combination and order of the catalyst gases can be arbitrarily selected. Further, when changing the supply amount of the catalyst gas, the supply amount may be changed from a small flow rate to a large flow rate, or may be changed from a large flow rate to a small flow rate. The supply amount of the catalyst gas may be changed only once or a plurality of times. At this time, the supply amount of the catalyst gas may be increased or decreased stepwise from a small flow rate to a large flow rate, or from a large flow rate to a small flow rate, or may be changed up and down appropriately in any combination. .

  According to this modification, the same effect as the film forming sequence shown in FIG. Further, according to this modification, the C concentration in the SiOC film can be changed in the film thickness direction. By changing the C concentration in the SiOC film in the film thickness direction, the relative Si concentration and O concentration in the film can also be changed in the film thickness direction. As a result, for example, the etching resistance and dielectric constant of the SiOC film can be changed in the film thickness direction.

(Modification 4)
1 is not limited to the case of using a substrate processing apparatus having a plurality of source gas supply lines and catalyst gas supply lines as shown in FIG. 1, and only a specific gas supply line is provided among the plurality of gas supply lines shown in FIG. It is also possible to use a substrate processing apparatus. However, when using a substrate processing apparatus equipped with a plurality of gas supply lines, a specific gas can be selected from a plurality of gases according to the desired film composition, etc., by appropriately selecting the gas supply line to be used. It becomes easy to supply. In addition, a single substrate processing apparatus can be used to form films having various composition ratios and film qualities for general purpose and with good reproducibility. In addition, it is possible to ensure the degree of freedom of apparatus operation when adding or replacing gas types.

(Modification 5)
The SiOC film forming step and the SiOC film modifying step may be performed in different processing chambers.

  For example, the SiOC film forming step is performed in a processing chamber 201 (hereinafter also referred to as a first processing chamber) provided in the substrate processing apparatus (hereinafter also referred to as a first substrate processing portion) shown in FIG. The operation of each part constituting the first substrate processing unit is controlled by the first control unit. A cycle including steps 1b and 2b similar to steps 1a and 2a described above is performed a predetermined number of times using the first substrate processing unit. Thereafter, purge in the processing chamber 201, return to atmospheric pressure, boat unload, and wafer discharge are sequentially performed. Subsequently, a step of heat-treating the SiOC film formed on the wafer 200 taken out from the boat 217, that is, a SiOC film modification step is performed in a processing chamber different from the processing chamber 201. At this time, for example, a substrate processing apparatus configured in the same way as the substrate processing apparatus shown in FIG. ) Provided in the processing chamber (hereinafter also referred to as a second processing chamber). The operation of each part constituting the second substrate processing unit is controlled by the second control unit. Using the second substrate processing unit, wafer charging and boat loading are sequentially performed in the same manner as when the SiOC film forming process is performed in the first substrate processing unit. Further, the pressure adjustment and the temperature adjustment are performed in the same manner as when performing the SiOC film modification process of the above-described embodiment. Thereafter, as in the above-described embodiment, the first heat treatment, the second heat treatment, the purge, the return to atmospheric pressure, the boat unloading, and the wafer discharge are sequentially executed. The processing conditions and the processing procedure in this modification are the same as the film forming sequence shown in FIG.

  As described above, the SiOC film forming step and the SiOC film modifying step are not only performed in the same processing chamber 201 (in-situ), but also different processing chambers (first processing chamber and second processing chamber). ) (With Ex-Situ). If both processes are performed in In-situ, the wafer 200 can be consistently processed without being exposed to the air during the process, and the film can be stably processed while being kept under vacuum. Can do. If both processes are performed in Ex-Situ, the temperature in each processing chamber can be set in advance, for example, to the processing temperature in each process or a temperature close thereto, thereby reducing the time required for temperature adjustment and improving production efficiency. Can be increased.

  In this modification, a substrate processing system is mainly configured by the first substrate processing unit that forms the SiOC film and the second substrate processing unit that heat-treats the SiOC film. However, the substrate processing system is not limited to the case where the first substrate processing unit and the second substrate processing unit are configured as independent devices (stand-alone devices) as described above. And the second substrate processing unit may be configured as one apparatus (cluster type apparatus) mounted on the same platform. Further, the apparatus for performing the SiOC film modification step may be configured as an apparatus having a configuration different from that of the substrate processing apparatus shown in FIG. 1, for example, a dedicated annealing apparatus (heat treatment furnace).

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to FIG. Also in the present embodiment, the substrate processing apparatus shown in FIGS. 1 and 2 is used as in the above-described embodiment. In the following description, the operation of each part constituting the substrate processing apparatus is controlled by the controller 121.

In the film forming sequence of this embodiment,
Supplying a BTCSM gas as a source gas containing Si, C and Cl and having a Si—C bond to the wafer 200;
Supplying an O ₃ gas as an oxidizing gas to the wafer 200;
Supplying a TEA gas as a catalyst gas to the wafer 200;
Is performed a predetermined number of times (n times) to form a SiOC film as a thin film containing Si, O, and C on the wafer 200.

At this time, the step of supplying the BTCSM gas is performed in a state where the step of supplying the TEA gas is not performed, and the step of supplying the O ₃ gas is performed in a state where the step of supplying the TEA gas is performed.

  In addition, after performing the SiOC film forming step, the SiOC film modifying step is performed in the same manner as in the above-described embodiment.

  Hereinafter, in the SiOC film forming process of the present embodiment, differences from the above-described embodiment will be described in detail.

(SiOC film formation process)
After the wafer charge, boat load, pressure adjustment, and temperature adjustment, the following two steps 1c and 2c are sequentially executed.

[Step 1c]
(BTCSM gas supply)
BTCSM gas is supplied to the wafer 200 in the same procedure as in step 1a of the film forming sequence shown in FIG. At this time, the valves 243c and 243i are closed, and the supply of BTCSM gas to the wafer 200 is stopped, that is, the supply of amine catalyst gas such as pyridine gas or TEA gas is stopped, that is, the amine catalyst gas is not supplied. Perform in the state. That is, when the BTCSM gas is supplied to the wafer 200, the catalyst gas is not supplied.

Further, in order to prevent the BTCSM gas from entering the buffer chamber 237 and the nozzles 249b and 249c, the valves 243k and 243l are opened, and N ₂ gas is allowed to flow into the gas supply pipes 232k and 232l. The N ₂ gas is supplied into the processing chamber 201 through the gas supply pipes 232b and 232c, the nozzles 249b and 249c, and the buffer chamber 237, and is exhausted from the exhaust pipe 231.

At this time, the APC valve 244 is appropriately adjusted so that the pressure in the processing chamber 201 is, for example, 1 to 13330 Pa, preferably 133 to 2666 Pa. The supply flow rate of the BTCSM gas controlled by the MFC 241a is, for example, a flow rate in the range of 1 to 2000 sccm. The supply flow rate of the N ₂ gas controlled by the MFCs 241j to 241l is, for example, a flow rate in the range of 100 to 10000 sccm. The time for supplying the BTCSM gas to the wafer 200, that is, the gas supply time (irradiation time) is, for example, 1 to 100 seconds, preferably 5 to 60 seconds.

At this time, the temperature of the heater 207 is such that the temperature of the wafer 200 becomes a temperature in the range of, for example, room temperature to 150 ° C., preferably room temperature to 100 ° C., more preferably 50 ° C. to 100 ° C. Set. When the catalyst gas is not supplied when the BTCSM gas is supplied, if the temperature of the wafer 200 is less than 250 ° C., BTCSM is difficult to be chemically adsorbed on the wafer 200, and a practical film formation rate may not be obtained. In the present embodiment, by using a combination of O ₃ gas and TEA gas in the next step 2a, even if the temperature of the wafer 200 is less than 250 ° C., this can be eliminated. Assuming that step 2a is performed next, if the temperature of the wafer 200 is set to 150 ° C. or lower, further 100 ° C. or lower, the amount of heat applied to the wafer 200 can be reduced, and the heat history received by the wafer 200 Control can be performed satisfactorily. At this time, if the temperature is higher than room temperature, a sufficient film forming rate can be obtained. Therefore, the temperature of the wafer 200 is set to a temperature in the range of room temperature to 150 ° C., preferably room temperature to 100 ° C., more preferably 50 ° C. to 100 ° C.

  By supplying BTCSM gas to the wafer 200 under the above-described conditions, a C layer having a thickness of, for example, less than one atomic layer to several atomic layers is formed on the wafer 200 (surface underlayer) as a first layer. Then, a Si-containing layer containing Cl and Cl is formed. As described above, for example, under a low temperature condition of 150 ° C. or lower, an adsorption layer of BTCSM gas based on physical adsorption with insufficient thermal decomposition, that is, a physical adsorption layer of BTCSM gas is mainly formed as the first layer. It is thought that there is.

  As described above, if the first layer is mainly composed of the BTCSM gas physical adsorption layer, the first layer is difficult to be fixed on the wafer 200 or the like. Further, even if an oxidation treatment is performed thereafter, the first layer is hardly changed to a SiOC layer having a strong bond. That is, when the catalyst gas is not supplied when the BTCSM gas is supplied, the oxidation reaction of the first layer may not easily proceed even if the catalyst gas is supplied in the subsequent oxidation treatment. As a result, the deposition rate of the SiOC film may decrease or it may become impossible to form the SiOC film.

  In order to solve such a problem, in the above-described embodiment, the first layer is fixed on the wafer 200 by supplying the catalyst gas in both the step of supplying the source gas and the step of supplying the oxidizing gas. I try to encourage them. As described above, the catalyst gas weakens the bonding force of the O—H bonds existing on the surface of the wafer 200 and promotes the thermal decomposition reaction of the BTCSM gas. Formation can be promoted, and the first layer can be firmly fixed on the wafer 200.

On the other hand, in this embodiment, the catalyst gas is used only in the next step 2c. However, in the present embodiment, in step 2c, an oxidizing gas having a strong oxidizing power (for example, O ₃ gas) and a catalytic gas having a strong catalytic action (for example, an amine-based catalyst gas such as TEA gas) are combined to form the above-mentioned. To solve the problems. By using these gases in combination, the oxidizing power of the oxidizing gas in step 2c can be significantly increased. As a result, even if the first layer is mainly composed of a physical adsorption layer of BTCSM gas, the oxidation reaction of the first layer can be surely advanced and changed to a SiOC layer having a strong bond. It becomes. That is, it is possible to form a SiOC layer having a strong bond with the base and a bond between adjacent molecules and atoms in the layer.

  In the present embodiment, it is not necessary to go through a complicated reaction system using a catalyst gas at least when the BTCSM gas is supplied, so that the film formation process can be easily constructed. Further, since the catalyst gas is not supplied when the BTCSM gas is supplied, it is possible to avoid the salt generated by the catalytic reaction from becoming a particle source, and to improve the quality of the film forming process. Further, since the catalyst gas is not supplied when the BTCSM gas is supplied, the amount of the catalyst gas used in the entire film formation process can be reduced, and the cost of the film formation process can be reduced.

(Residual gas removal)
Thereafter, the supply of BTCSM gas is stopped and residual gas is removed from the processing chamber 201 in the same procedure as in the above-described embodiment.

[Step 2c]
(O ₃ gas + TEA gas supply)
After step 1c is completed, O ₃ gas and TEA gas are flowed into the processing chamber 201. In step 2c, the opening / closing control of the valves 243g, 243i is performed in the same procedure as the opening / closing control of the valves 243a, 243c in step 2a of the film forming sequence shown in FIG.

At this time, the supply flow rate of the O ₃ gas controlled by the MFC 241 g is set to a flow rate within a range of 1000 to 10000 sccm, for example. The TEA gas supply flow rate controlled by the MFC 241i is, for example, in the range of 0.01 to 100, more preferably 0.05 to 10 in terms of the ratio of O ₃ gas supply flow rate (sccm) / TEA gas supply flow rate (sccm). Set the flow rate inside. The supply flow rate of the N ₂ gas controlled by the MFCs 241j to 241l is, for example, a flow rate in the range of 100 to 10000 sccm. The time for supplying the O ₃ gas and the TEA gas to the wafer 200, that is, the gas supply time (irradiation time) is, for example, 1 to 100 seconds, preferably 5 to 60 seconds. As for the temperature of the heater 207, the temperature of the wafer 200 is the same temperature range as when the BTCSM gas is supplied in Step 1c, for example, room temperature to 150 ° C., preferably room temperature to 100 ° C., more preferably 50 ° C. to 100 ° C. Set the temperature within the range of ℃ or less. Other processing conditions are, for example, the same processing conditions as those in step 2a of the film forming sequence shown in FIG.

The O ₃ gas supplied into the processing chamber 201 is activated by heat and exhausted from the exhaust pipe 231. At this time, the heat activated O ₃ gas is supplied to the wafer 200. The gas flowing into the processing chamber 201 is a thermally activated O ₃ gas, and no BTCSM gas is flowing into the processing chamber 201. Therefore, the O ₃ gas does not cause a gas phase reaction and is supplied to the wafer 200 in an activated state, and the first layer (Si containing C and Cl) formed on the wafer 200 in Step 1c. It reacts with at least a part of the containing layer). As a result, the first layer is thermally oxidized by non-plasma and is changed into a second layer containing Si, O, and C, that is, a SiOC layer.

TEA gas, promote decomposition of the O ₃ gas, to improve the oxidizing power of the O ₃ gas, acts as a catalyst gas for promoting the reaction between the O ₃ gas and the first layer. In particular, by combining the O ₃ gas and the TEA gas, the oxidizing power of the O ₃ gas can be significantly improved beyond the range predicted by a normal catalytic reaction. As described above, if the catalyst gas is not supplied when the BTCSM gas is supplied and the thermal decomposition of the BTCSM gas is insufficient, sufficient reactivity can be obtained even if the catalyst gas is supplied in the subsequent oxidizing gas supply process. It may be difficult to obtain. However, by supplying the O ₃ gas and the TEA gas together, for example, in Step 1c, as the first layer, the BTCSM gas adsorption layer by physical adsorption that is not sufficiently pyrolyzed, that is, the BTCSM gas physical adsorption layer Even if mainly formed, the oxidation reaction between the O ₃ gas and the first layer can proceed appropriately. That is, the oxidizing power of the O ₃ gas can be remarkably increased by the action of the TEA gas, whereby the oxidation treatment can be reliably performed on the physical adsorption layer of the BTCSM gas. As a result, it is possible to form a SiOC layer having strong bonds with the base and bonds between adjacent molecules and atoms.

(Residual gas removal)
Thereafter, the valve 243g is closed and the supply of O ₃ gas is stopped. Further, the valve 243i is closed, and the supply of the TEA gas is stopped. And the residual gas from the inside of the process chamber 201 is removed in the same procedure as the above-mentioned embodiment.

(Performed times)
By setting the above-described steps 1c and 2c as one cycle and performing this cycle one or more times, that is, a predetermined number of times (n times), a SiOC film having a predetermined composition and a predetermined thickness can be formed on the wafer 200. it can. The point that it is preferable to repeat this cycle a plurality of times is the same as in the above-described embodiment.

(SiOC film modification process)
Also in this embodiment, the SiOC film formed under the low temperature condition may contain a large amount of impurities such as moisture and Cl and C _x H _y- based impurities. Therefore, pressure adjustment, temperature adjustment, first heat treatment, second heat treatment, purge and return to atmospheric pressure are performed in the same procedure and processing conditions as in the above-described embodiment to remove impurities in the SiOC film, The SiOC film is modified. As a result, a SiOC film having a higher etching resistance and a lower dielectric constant than that of the SiOC film before the SiOC film modification step is obtained.

  Thereafter, boat unloading and wafer discharging are performed in the same procedure as in the above-described embodiment, and the film forming process of this embodiment is completed.

(2) Effects According to the Present Embodiment According to the present embodiment, in addition to the same effects as those of the above-described embodiment, the following one or more effects are achieved.

(A) BTCSM gas is supplied to the wafer 200 while supply of the catalyst gas to the wafer 200 is stopped. Thereby, the film forming process can be simplified. Further, the salt generated when the catalyst gas is supplied when the BTCSM gas is supplied is not generated, and the generation of particles can be suppressed. Further, it is possible to suppress the amount of catalyst gas used as viewed in the entire film formation process and to reduce the manufacturing cost.

(B) Supply the O ₃ gas to the wafer 200 in a state where the TEA gas is supplied to the wafer 200. Thereby, the oxidizing power of O ₃ gas can be remarkably increased. By combining the O ₃ gas and the amine catalyst gas, the oxidizing power of the O ₃ gas can be significantly increased beyond the range that can be predicted by a normal catalytic reaction. Therefore, sufficient reactivity with respect to the first layer can be obtained without supplying the catalyst gas when the BTCSM gas is supplied, and the oxidation reaction between the O ₃ gas and the first layer can proceed appropriately. It becomes. In addition, the rate of the oxidation reaction can be improved and the deposition rate of the SiOC film can be maintained.

As the amine catalyst gas combined with O ₃ gas, TEA gas is excellent, and then pyridine gas and then piperidine gas are considered suitable. This is based on the fact that the temperature range in which the SiOC film can be formed is the widest when the TEA gas is used as the catalyst gas, then the pyridine gas is widely used, and then the piperidine gas is widely used. .

(C) According to the present embodiment, the same effects as those of the above-described embodiment described with reference to FIG. However, the various effects shown in the above-described embodiment may be more remarkable in the above-described embodiment than in this embodiment. For example, the effect of lowering the dielectric constant of the SiOC film may be more prominent in the above-described embodiment using H ₂ O gas and pyridine gas than in this embodiment using O ₃ gas and TEA gas. is there. As this factor, for example, the use of H ₂ O gas as the oxidizing gas increases the degree of porosity of the SiOC film compared to the case where O ₃ gas is used as the oxidizing gas. By using H ₂ O gas as the oxidizing gas, a SiOC film containing more water than when using O ₃ gas as the oxidizing gas is formed. Then, by applying the first heat treatment and the second heat treatment to the SiOC film containing a large amount of moisture, more fine holes (pores), that is, fine spaces are generated in the film, and the SiOC film becomes porous. May go further.

(3) Modification of this Embodiment The film-forming sequence of this embodiment is not limited to the aspect shown to Fig.6 (a), For example like the modification shown to FIG.6 (b) or FIG.6 (c). The SiO film can be formed on the wafer 200 by modification.

  In this case, HCDS gas, BDEAS gas, or the like is used as the source gas instead of BTCSM gas. In step 1c for supplying HCDS gas, BDEAS gas, etc., the opening / closing control of the valve 243e and the valve 243f is performed in the same procedure as the opening / closing control of the valve 243a in step 1c of the film forming sequence shown in FIG. The supply flow rates of the HCDS gas and the BDEAS gas are also the same as the supply flow rates of the BTCSM gas in step 1c of the film forming sequence shown in FIG. Other processing conditions are, for example, the same processing conditions as those in step 1c of the film forming sequence shown in FIG.

As described above, the SiO film formed under the low temperature condition may contain impurities such as moisture. When HCDS gas is used as the source gas, impurities such as Cl may be contained in the SiO film. When BDEAS gas is used as the source gas, impurities such as C, H, and N may be contained in the SiO film. By performing the first heat treatment and the second heat treatment on the SiO film under the same procedure and processing conditions as in the above-described embodiment, impurities in the SiO film are removed, and the SiO film is modified, whereby the SiO film A SiO film having a higher etching resistance and a lower dielectric constant than that of the SiO film before the modification step is obtained.

<Third Embodiment>
Next, a third embodiment of the present invention will be described with reference to FIGS. 7 (a) and 7 (b). Also in the present embodiment, the substrate processing apparatus shown in FIGS. 1 and 2 is used as in the above-described embodiment. In the following description, the operation of each part constituting the substrate processing apparatus is controlled by the controller 121.

In the film forming sequence of this embodiment,
The process of supplying HCDS gas as a source gas containing Si and Cl to the wafer 200 is performed in a state where the process of supplying pyridine gas as a catalyst gas to the wafer 200 is performed (Step 1d). The step of supplying the H ₂ O gas as the oxidizing gas is performed in a state where the step of supplying the pyridine gas as the catalyst gas to the wafer 200 is performed (step 2d), and a set including these steps is performed a predetermined number of times (m by _once) to perform the steps of forming a SiO film as a first thin film containing Si and O,
The step of supplying BTCSM gas as a source gas containing Si, C, and Cl to the wafer 200 and having a Si—C bond is performed in a state where the step of supplying pyridine gas as a catalyst gas to the wafer 200 is performed ( Step 1e), a process of supplying H ₂ O gas as an oxidizing gas to the wafer 200 is performed in a state where a process of supplying pyridine gas as a catalyst gas to the wafer 200 is performed (Step 2e). Forming a SiOC film as a second thin film containing Si, O, and C by performing a set including a predetermined number of times (m ₂ times);
Is performed a predetermined number of times (n times), thereby performing a step of forming a laminated film of the SiO film and the SiOC film on the wafer 200.

  Further, after forming a laminated film of the SiO film and the SiOC film, the modifying process of the laminated film is performed in the same manner as in the above-described embodiment.

  Hereinafter, the differences between the SiO film and the SiOC film forming process of the present embodiment and the above-described embodiment will be described in detail.

(SiO film formation process)
After wafer charge, boat load, pressure adjustment, and temperature adjustment, the following two steps 1d and 2d are sequentially executed.

[Step 1d]
(HCDS gas + pyridine gas supply)
HCDS gas is supplied to the wafer 200 in the same procedure as in step 1c of the film forming sequence shown in FIG. Further, pyridine gas is supplied to the wafer 200 in the same procedure as in step 1a of the film forming sequence shown in FIG. The processing conditions at this time are, for example, the same processing conditions as those in step 1c of the film forming sequence shown in FIG. 6B and step 1a of the film forming sequence shown in FIG. Pyridine gas also exhibits catalytic action similar to that of BTCSM gas for HCDS gas.

  As a result, a Si-containing layer containing Cl having a thickness of, for example, less than one atomic layer to several atomic layers is formed on the wafer 200 as the first layer. By flowing the HCDS gas simultaneously with the pyridine gas, a Si-containing layer containing Cl can be formed on the wafer 200 even under a relatively low temperature condition of, for example, 150 ° C. or less.

(Residual gas removal)
Thereafter, the supply of the HCDS gas and the pyridine gas is stopped in the same procedure as in the above embodiment, and the residual gas is removed from the processing chamber 201.

[Step 2d]
(H ₂ O gas + pyridine gas supply)
After step 1d is completed and the residual gas in the processing chamber 201 is removed, H ₂ O gas and pyridine gas are applied to the wafer 200 by the same supply procedure as in step 2a of the film forming sequence shown in FIG. And supply. The processing conditions at this time are, for example, the same processing conditions as those in step 2a of the film forming sequence shown in FIG. As a result, the first layer is thermally oxidized by non-plasma and is changed to a second layer containing Si and O, that is, a silicon oxide layer (SiO layer).

(Residual gas removal)
Thereafter, the supply of H ₂ O gas and pyridine gas is stopped in the same procedure as in the above embodiment, and the residual gas is removed from the processing chamber 201.

(Performed times)
The above-described steps 1d and 2d are set as one set, and this set is performed at least once, that is, a predetermined number of times (m ₁ time) to form a SiO film having a predetermined composition and a predetermined film thickness on the wafer 200. Can do. The point that it is preferable to repeat this set a plurality of times is the same as in the above-described embodiment.

(SiOC film formation process)
Next, steps 1e and 2e are sequentially executed under the same procedure and processing conditions as the steps 1a and 2a of the film forming sequence shown in FIG. By setting steps 1e and 2e as one set and performing this set one or more times, that is, a predetermined number of times (m ₂ times), a SiOC film having a predetermined composition and a predetermined thickness can be formed on the SiO film. . The point that it is preferable to repeat this set a plurality of times is the same as in the above-described embodiment.

(Performed times)
The above-mentioned SiO film forming step and SiOC film forming step are set as one cycle, and this cycle is performed once or more, that is, a predetermined number of times (n times), whereby a laminated film of the SiO film and the SiOC film is formed on the wafer 200. Is formed. The SiO film formation process and the SiOC film formation process may be started from either.

  As shown in FIG. 7A, by performing a cycle including the SiO film forming process and the SiOC film forming process once, a stacked film (stack film) in which one SiO film and one SiOC film are stacked. ) Can be formed.

  Further, as shown in FIG. 7B, by performing a cycle including the SiO film forming step and the SiOC film forming step a plurality of times, a laminated film (laminate film) in which a plurality of SiO films and SiOC films are respectively laminated. ) Can be formed. FIG. 7B shows an example in which a cycle including the SiO film formation step and the SiOC film formation step is repeated twice.

(Laminated film modification process)
Also in this embodiment, the laminated film of the SiO film and the SiOC film formed under a low temperature condition may contain a large amount of impurities such as moisture and Cl, and C _x H _y impurities. Therefore, pressure adjustment, temperature adjustment, first heat treatment, second heat treatment, purge and return to atmospheric pressure are performed in the same procedure and processing conditions as in the above-described embodiment to remove impurities in the stacked film, Modify the laminated film. As a result, it is possible to obtain a laminated film having a higher etching resistance and a lower dielectric constant than the laminated film before the laminated film modification step.

  Thereafter, boat unloading and wafer discharging are performed in the same procedure as in the above-described embodiment, and the film forming process of this embodiment is completed.

  Also according to the present embodiment, the same effects as those of the above-described embodiment can be obtained.

Further, by controlling the ratio between the film thickness of the SiO film and the film thickness of the SiOC film, for example, by controlling the ratio of the number of times (m ₁ , m ₂ ) of each set described above, the film is finally formed. It is possible to precisely control the composition ratio of the laminated film. Further, in the film forming sequence shown in FIG. 7B, the film thickness of the SiO film and the SiOC film is 5 nm or less, preferably 1 nm or less, so that the finally formed laminated film is unified in the laminating direction. In other words, the film can be a nanolaminate film having integral characteristics that is integral to the film as a whole. In addition, the film thicknesses of the SiO film and the SiOC film are each set to 5 nm or less, preferably 1 nm or less by setting the number of executions of the above set (m ₁ time, m ₂ times) to about 1 to 10 times, respectively. it can.

(2) Modification of this Embodiment The film-forming sequence of this embodiment is not limited to the mode shown in FIGS. 7 (a) and 7 (b), and is shown in FIGS. 8 (a) and 8 (b). It can also be changed as in the modification. That is, in the SiO film forming process, it is not necessary to supply the catalyst gas. In the SiO film forming step, HCDS gas may be used as the source gas, for example, BDEAS gas containing Si, C and N and having a Si—N bond. Further, in the SiO film forming step, O ₂ gas activated by plasma, that is, O ₂ gas excited to a plasma state may be used as the oxidizing gas.

  In step 1f of supplying BDEAS gas, the opening / closing control of the valve 243f is performed in the same procedure as the opening / closing control of the valve 243e in step 1d of the film forming sequence shown in FIGS. 7 (a) and 7 (b). At this time, the valves 243c and 243i are closed, and the supply of the BDEAS gas to the wafer 200 is performed while the supply of amine-based catalyst gas such as pyridine gas or TEA gas is stopped. The supply flow rate of the BDEAS gas is, for example, the same as the supply flow rate of the HCDS gas in step 1d of the film forming sequence shown in FIGS. 7 (a) and 7 (b). Other processing conditions are, for example, the same processing conditions as those in step 1d of the film forming sequence shown in FIGS. 7 (a) and 7 (b).

  By supplying BDEAS gas to the wafer 200, Si containing N and C having a thickness of less than one atomic layer to several atomic layers, for example, as the first layer on the wafer 200 (underlayer film on the surface). A containing layer is formed. The BDEAS gas is a gas that is easily adsorbed on the wafer 200 and the like and has high decomposability and reactivity. Therefore, for example, the first layer can be formed on the wafer 200 even under a relatively low temperature condition of 150 ° C. or lower.

In step 2f of supplying O ₂ gas activated by plasma, the opening / closing control of the valve 243h is the same as the opening / closing control of the valve 243b in step 2d of the film forming sequence shown in FIGS. 7 (a) and 7 (b). Follow the procedure. At this time, the valves 243c and 243i are closed, and the O ₂ gas is supplied to the wafer 200 in a state where the supply of amine-based catalyst gas such as pyridine gas or TEA gas is stopped. The supply flow rate of O ₂ gas controlled by the MFC 241h is, for example, a flow rate in the range of 100 to 10000 sccm. The high frequency power applied between the rod-shaped electrodes 269 and 270 is, for example, power in the range of 50 to 1000 W. The pressure in the processing chamber 201 is, for example, a pressure in the range of 1 to 100 Pa. By using plasma, the O ₂ gas can be activated even when the pressure in the processing chamber 201 is set to such a relatively low pressure zone. The time for supplying the active species obtained by plasma excitation of the O ₂ gas to the wafer 200, that is, the gas supply time (irradiation time) is, for example, in the range of 1 to 100 seconds, preferably 5 to 60 seconds. Time. Other processing conditions are, for example, the same processing conditions as those in step 2e of the film forming sequence shown in FIGS. 7 (a) and 7 (b).

By supplying O ₂ gas activated by plasma to the wafer 200, an oxidation process is performed on the first layer (Si-containing layer containing N and C) formed on the wafer 200. The first layer is changed to a second layer containing Si and O, that is, a SiO layer.

  Also according to this modification, the same effect as the film forming sequence shown in FIGS. 7A and 7B can be obtained.

<Other embodiments>
The embodiment of the present invention has been specifically described above. However, the present invention is not limited to the above-described embodiments and modifications, and various modifications can be made without departing from the scope of the invention.

  The temperature control sequence of the heat treatment process of the present invention, that is, the annealing sequence is not limited to the above-described embodiment, and various modifications can be made as shown in FIGS. 14 and 15, for example. FIG. 14A shows an annealing sequence when the second temperature is higher than the first temperature, as in the above-described embodiment. 14 (b) to 14 (d) show modifications thereof. FIG. 15 shows an annealing sequence when the second temperature is set equal to the first temperature. In these figures, the horizontal axis represents elapsed time (minutes) and the vertical axis represents wafer temperature (° C.).

  In the annealing sequence shown in FIG. 14A, the temperature of the wafer 200 after the film formation is raised to the first temperature, and the temperature is kept constant at the first temperature for a predetermined time, whereby the first heat treatment is performed. The process is performed. Thereafter, the temperature of the wafer 200 is increased to a second temperature higher than the first temperature, and the temperature is kept constant at the second temperature for a predetermined time, so that the second heat treatment step is performed. Yes. Thereafter, the temperature of the wafer 200 is lowered to a temperature at which the wafer 200 can be unloaded.

  According to this annealing sequence, in the first heat treatment step, by keeping the temperature of the wafer 200 constant at a first temperature lower than the second temperature for a predetermined time, as described above, an undesired reaction can be ensured. Can be prevented. Further, by sufficiently securing the time for maintaining the temperature of the wafer 200 at the first temperature, it is possible to surely desorb the first impurities (such as moisture and Cl) from the SiOC film.

Thereafter, in the second heat treatment step, the temperature of the wafer 200 is kept constant at a second temperature higher than the first temperature for a predetermined time, so that the second impurity in the second heat treatment step is maintained as described above. Desorption of (C _x H _y- based impurities) can be performed quickly. Further, at this time, since a substance (moisture, Cl, or the like) that causes an undesired reaction is not generated, it is possible to reliably suppress the undesired reaction described above. In addition, by sufficiently securing the time for maintaining the temperature of the wafer 200 at the second temperature, it is possible to reliably desorb the second impurity from the SiOC film.

  In the annealing sequence shown in FIG. 14B, after the temperature of the wafer 200 after film formation is raised to the first temperature, the temperature is raised to the second temperature without being kept constant. Yes. When the temperature of the wafer 200 reaches the second temperature, the temperature is lowered without maintaining the temperature constant. In this annealing sequence, after the temperature of the wafer 200 reaches a temperature at which desorption of the first impurity from the SiOC film is started (temperature near the first temperature), the first from the SiOC film is reached. A first heat treatment step is performed until the desorption of impurities is completed. Further, after the temperature of the wafer 200 reaches a temperature at which the desorption of the second impurity from the SiOC film becomes active (a temperature near the second temperature), the desorption of the second impurity from the film. Until the process is completed, the second heat treatment step is performed. In addition, after the desorption of the first impurity from the SiOC film is almost completed, that is, after the ratio of the second impurity in the desorbed impurity from the film becomes dominant, A period until the desorption of the second impurity becomes active may be included in the second heat treatment step.

  According to this annealing sequence, the first heat treatment step and the second heat treatment step can be appropriately performed in this order by appropriately adjusting the temperature increase rate and the temperature decrease rate of the wafer 200. It becomes possible.

  For example, a rate of temperature increase until the temperature of the wafer 200 reaches the first temperature, and a rate of temperature increase until the temperature of the wafer 200 reaches the second temperature after the temperature exceeds the first temperature. By suppressing at least one of the sizes at a low level, it is possible to ensure a sufficient implementation time while reliably preventing the undesired reaction described above in the first heat treatment step. Thereby, it is possible to reliably desorb the first impurity from the SiOC film. For example, a rate of temperature increase until the temperature of the wafer 200 reaches the first temperature, and a rate of temperature increase until the temperature of the wafer 200 reaches the second temperature after the temperature exceeds the first temperature. By making one of these smaller than the other, it is possible to sufficiently secure the time for performing the first heat treatment step, and it is possible to surely desorb the first impurity from the SiOC film. Furthermore, the total time required can be shortened.

  Further, for example, among a temperature rising rate from when the temperature of the wafer 200 exceeds the first temperature until reaching the second temperature, and a temperature decreasing rate after the temperature of the wafer 200 reaches the second temperature By suppressing at least one of the sizes at a low level, it is possible to sufficiently secure the execution time of the second heat treatment step. As a result, it is possible to reliably desorb the second impurity from the SiOC film. Further, at this time, since a substance that causes an undesired reaction is not generated, the above-described undesired reaction can be reliably suppressed. For example, of a rate of temperature rise until the temperature reaches the second temperature after the temperature of the wafer 200 exceeds the first temperature, and a rate of temperature decrease after the temperature of the wafer 200 reaches the second temperature By making one smaller than the other, it is possible to secure a sufficient time for performing the second heat treatment step, and it is possible to surely desorb the second impurity from the SiOC film. Furthermore, the total time required can be shortened.

  According to this annealing sequence, control for maintaining the temperature of the wafer 200 at a constant level is not performed, so that temperature control can be simplified. For example, when the temperature of the wafer 200 immediately after the film formation is raised to the second temperature, the first heat treatment step and the second heat treatment step can be performed by keeping in mind that the rate of temperature rise is sufficiently low. In this order, each can be performed appropriately.

  The annealing sequence shown in FIGS. 14C and 14D is a combination of the annealing sequences shown in FIGS. 14A and 14B. In the annealing sequence shown in FIG. 14C, the temperature of the wafer 200 is continuously raised until it reaches the second temperature, and when the temperature of the wafer 200 reaches the second temperature, the temperature is kept constant for a predetermined time. Then, I try to lower it. In the annealing sequence shown in FIG. 14D, when the temperature of the wafer 200 reaches the first temperature, the temperature is kept constant for a predetermined time, and then the temperature of the wafer 200 is raised to the second temperature. When the temperature of the wafer 200 reaches the second temperature, the temperature is lowered without maintaining the temperature constant. Also in these annealing sequences, the same effects as the annealing sequences shown in FIGS. 14A and 14B are obtained. Note that the annealing sequences shown in FIGS. 14A, 14B, 14C, and 14D can be used in appropriate combination.

  The annealing sequence shown in FIG. 15 shows an example in which the second temperature is set equal to the first temperature. In this annealing sequence, the temperature of the wafer 200 after film formation is raised to the first temperature, then the temperature is kept constant for a predetermined time, and then lowered.

As described above, when the temperature of the wafer 200 is raised to the first temperature, desorption of the first impurity and the second impurity from the SiOC film is started. At that time, the desorption of the first pure product is completed before the desorption of the second impurity. In this annealing sequence, after the temperature of the wafer 200 reaches a temperature at which desorption of the first impurity from the SiOC film starts (a temperature near the first temperature), the first temperature from the SiOC film is reached. The first heat treatment step is performed until the desorption of the impurities is completed. Further, after the desorption of the first impurity from the SiOC film is almost completed, that is, after the ratio of the second impurity in the desorbed impurity from the film becomes dominant, The second heat treatment step is performed until the desorption of the second impurity is completed. Note that the period from the start of the desorption of the second impurity from the SiOC film to the completion of the desorption of the first impurity from the SiOC film is included in the second heat treatment step. Also good. That is, it may be considered that the first heat treatment step and the second heat treatment step are started simultaneously, the first heat treatment step is completed first, and then the second heat treatment step is completed. Note that even if the first heat treatment step and the second heat treatment step are started at the same time, the first temperature does not include the temperature zone in which the above-described unwanted reaction occurs, so the first heat treatment step and the second heat treatment step When the heat treatment step is performed simultaneously, the above-mentioned undesired reaction does not occur.

  According to this annealing sequence, it is possible to appropriately perform the first heat treatment step and the second heat treatment step by ensuring a sufficient time for maintaining the temperature of the wafer 200 at the first temperature. Become. That is, after the first heat treatment step is completed, the second heat treatment step is performed without further increasing the temperature of the wafer 200 by ensuring a sufficient time for maintaining the temperature of the wafer 200 at the first temperature. It becomes possible to carry out reliably.

  Further, according to this annealing sequence, the second temperature is set to a temperature equivalent to the first temperature, that is, the temperature of the wafer 200 is not increased to a temperature exceeding the first temperature. Control of the thermal history received can be performed satisfactorily. Also, according to this annealing sequence, it is not necessary to raise the temperature of the wafer 200 to a temperature exceeding the first temperature, so that the heater 207 having a relatively small output can be used, and the manufacturing cost of the substrate processing apparatus can be reduced. Can be reduced.

  In addition, according to this annealing sequence, control for increasing the temperature of the wafer 200 in two steps is not performed, so that temperature control can be simplified. For example, if the temperature of the wafer 200 immediately after the film formation is raised to the first temperature and then it is noted that sufficient time is maintained to maintain the temperature constant, the first heat treatment step and the first heat treatment step are performed. The two heat treatment steps can be performed appropriately.

  In the above-described embodiments and the like, the example in which the inert gas, the purge gas, and the oxygen-free gas are all supplied from the same gas supply system has been described. The present invention is not limited to this mode, and all or part of the inert gas supply system, the purge gas supply system, and the oxygen-free gas supply system may be provided as a separate gas supply system. However, when an oxygen-free atmosphere is generated in the processing chamber 201 only by the exhaust system, it is not necessary to provide an oxygen-free gas supply system.

  Further, in the above-described embodiment, when the Si-containing layer is changed to the SiOC layer or the SiO layer, an example of using an oxidation gas activated by heat together with the catalyst gas, that is, the catalyst gas and the oxidation gas are made of non-plasma. The example which supplies in an atmosphere (condition) was demonstrated. The present invention is not limited to this embodiment, and an oxidizing gas excited by plasma may be used together with the catalyst gas. That is, the catalyst gas and the oxidizing gas may be supplied in a plasma atmosphere (under conditions). The processing conditions at this time can be set to the same processing conditions as in the above-described embodiment or modification, for example.

Moreover, in the above-described embodiment, an example in which an Si-based thin film such as a SiOC film or a SiO film is formed using an oxidizing gas such as H ₂ O gas has been described. The present invention is not limited to this embodiment. For example, a nitriding gas may be used instead of the oxidizing gas, and a Si-containing layer containing C and Cl may be nitrided to form a Si-based thin film such as a SiCN film. Alternatively, an Si gas thin film such as a SiON film or a SiOCN film may be formed by appropriately combining an oxidizing gas or a nitriding gas. As the nitriding gas, for example, ammonia (NH ₃ ) gas, diazene (N ₂ H ₂ ) gas, hydrazine (N ₂ H ₄ ) gas, N ₃ H ₈ gas, a gas containing these compounds, or the like can be used. The processing conditions at this time can be set to the same processing conditions as in the above-described embodiment, for example.

  Moreover, in the above-described embodiment, the example in which the chlorosilane source gas is used as the source gas used for forming the SiOC film or the SiO film has been described. The present invention is not limited to this embodiment, and a halosilane source gas other than the chlorosilane source gas, for example, a fluorosilane source gas or a bromosilane source gas may be used. The processing conditions at this time can be set to the same processing conditions as in the above-described embodiment, for example.

  Along with miniaturization of transistors, there is a demand for lowering the film forming temperature, improving resistance to hydrogen fluoride (HF), and lowering the dielectric constant for the thin film constituting the sidewall spacer (SWS) of the gate electrode. . Further, ReRAM protective films developed as next-generation memories are required to be formed at a low temperature of 350 ° C. or lower, and MRAM protective films are required to be formed at a low temperature of 250 ° C. or lower. In response to such a demand, the present invention uses a source gas containing Si, C and a halogen element and having a Si—C bond, an oxidizing gas, and the like to form a Si-based thin film (SiOC film, SiOCN film, SiCN film) or the like. It can be suitably applied when forming a thin film.

  By using, as SWS, the Si-based thin film formed by the method of each of the above-described embodiments and modifications, it is possible to provide a device forming technique with low leakage current and excellent workability. Further, by using a Si-based thin film formed by the method of each of the above-described embodiments and modifications as an etch stopper, it is possible to provide a device forming technique with excellent workability. Further, according to each of the above-described embodiments and some modifications, it is possible to form an Si-based thin film having an ideal stoichiometric ratio without using plasma even in a low temperature region. Since a Si-based thin film can be formed without using plasma, it is possible to adapt to a process that is concerned about plasma damage, such as a DDP SADP film.

  In the above-described embodiment and the like, an example of forming a silicon-based thin film (SiO film, SiOC film, SiCN film, SiON film, SiOCN film) containing Si as a semiconductor element has been described, but the present invention is not limited thereto. It is not something. For example, the present invention is also applicable to the case of forming a metal thin film containing a metal element such as titanium (Ti), zirconium (Zr), hafnium (Hf), tantalum (Ta), aluminum (Al), molybdenum (Mo). Can be applied.

  For example, the present invention provides a titanium oxide film (TiO film), a zirconium oxide film (ZrO film), a hafnium oxide film (HfO film), a tantalum oxide film (TaO film), an aluminum oxide film (AlO film), a molybdenum oxide film ( The present invention can also be suitably applied when forming a metal oxide film such as a MoO film.

  Further, for example, the present invention includes a titanic acid carbonized film (TiOC film), a zirconic acid carbonized film (ZrOC film), a hafnium acid carbonized film (HfOC film), a tantalum acid carbonized film (TaOC film), an aluminum oxycarbide film (AlOC film) ) And a metal oxycarbide film such as a molybdate carbide film (MoOC film).

  Further, for example, the present invention provides a titanium carbonitride film (TiCN film), a zirconium carbonitride film (ZrCN film), a hafnium carbonitride film (HfCN film), a tantalum carbonitride film (TaCN film), and an aluminum carbonitride film (AlCN film). ) And a metal carbonitride film such as a molybdenum carbonitride film (MoCN film).

  Further, for example, the present invention provides a titanium oxynitride film (TiON film), a zirconium oxynitride film (ZrON film), a hafnium oxynitride film (HfON film), a tantalum oxynitride film (TaON film), an aluminum oxynitride film (AlON film) ), And a metal oxynitride film such as a molybdate oxynitride film (MoON film).

  Further, for example, the present invention provides a titanium oxycarbonitride film (TiOCN film), a zirconium oxycarbonitride film (ZrOCN film), a hafnium oxycarbonitride film (HfOCN film), a tantalum oxycarbonitride film (TaOCN film), The present invention can also be suitably applied when forming a metal oxycarbonitride film such as a nitride film (AlOCN film) or a molybdate oxycarbonitride film (MoOCN film).

  In this case, the source gas containing a metal element can be used as the source gas instead of the source gas containing Si in the above-described embodiment, and film formation can be performed in the same sequence as in the above-described embodiment.

For example, when forming a metal-based thin film (TiO film, TiOC film, TiCN film, TiON film, TiOCN film) containing Ti, the source gas containing Ti contains Ti, C, and a halogen element, and is a Ti-C bond. Or a source gas containing Ti and a halogen element can be used. Examples of the source gas containing Ti and a halogen element include a source gas containing Ti and a chloro group such as titanium tetrachloride (TiCl ₄ ), and a source gas containing Ti and a fluoro group such as titanium tetrafluoride (TiF ₄ ). Can be used. As the oxidizing gas, nitriding gas, amine-based catalyst gas, and oxygen-free gas, the same gas as that in the above-described embodiment can be used. The processing conditions at this time can be set to the same processing conditions as in the above-described embodiment, for example.

Further, for example, in the case of forming a metal-based thin film (ZrO film, ZrOC film, ZrCN film, ZrON film, ZrOCN film) containing Zr, Zr, C, and a halogen element are included as a source gas containing Zr, and Zr—C A source gas having a bond or a source gas containing Zr and a halogen element can be used. Examples of the source gas containing Zr and a halogen element include source gases containing Zr and chloro groups such as zirconium tetrachloride (ZrCl ₄ ), and source gases containing Zr and fluoro groups such as zirconium tetrafluoride (ZrF ₄ ). Can be used. As the oxidizing gas, nitriding gas, amine-based catalyst gas, and oxygen-free gas, the same gas as that in the above-described embodiment can be used. The processing conditions at this time can be set to the same processing conditions as in the above-described embodiment, for example.

Further, for example, in the case of forming a metal-based thin film (HfO film, HfOC film, HfCN film, HfON film, HfOCN film) containing Hf, the source gas containing Hf contains Hf, C, and a halogen element, and Hf-C A source gas having a bond or a source gas containing Hf and a halogen element can be used. As the raw material gas containing Hf and halogen elements, for example, the raw material gas containing Hf and chloro group such as hafnium tetrachloride (HfCl _4), a raw material gas containing Hf and a fluoro group such as hafnium tetrafluoride (HfF ₄₎ Can be used. As the oxidizing gas, nitriding gas, amine-based catalyst gas, and oxygen-free gas, the same gas as that in the above-described embodiment can be used. The processing conditions at this time can be set to the same processing conditions as in the above-described embodiment, for example.

For example, in the case of forming a metal-based thin film containing Ta (TaO film, TaOC film, TaCN film, TaON film, TaOCN film), Ta, C and a halogen element are included as a source gas containing Ta, and Ta—C A source gas having a bond or a source gas containing Ta and a halogen element can be used. Examples of the source gas containing Ta and a halogen element include a source gas containing Ta and a chloro group such as tantalum pentachloride (TaCl ₅ ), and a source gas containing Ta and a fluoro group such as tantalum pentafluoride (TaF ₅ ). Can be used. As the oxidizing gas, nitriding gas, amine-based catalyst gas, and oxygen-free gas, the same gas as that in the above-described embodiment can be used. The processing conditions at this time can be set to the same processing conditions as in the above-described embodiment, for example.

Further, for example, in the case of forming a metal-based thin film (AlO film, AlOC film, AlCN film, AlON film, AlOCN film) containing Al, the source gas containing Al contains Al, C, and a halogen element, and Al—C A source gas having a bond or a source gas containing Al and a halogen element can be used. As the source gas containing Al and a halogen element, for example, a source gas containing Al and a chloro group such as aluminum trichloride (AlCl ₃ ), or a source gas containing Al and a fluoro group such as aluminum trifluoride (AlF ₃ ) is used. be able to. As the oxidizing gas, nitriding gas, amine-based catalyst gas, and oxygen-free gas, the same gas as that in the above-described embodiment can be used. The processing conditions at this time can be set to the same processing conditions as in the above-described embodiment, for example.

For example, when forming a metal-based thin film (MoO film, MoOC film, MoON film, MoOCN film) containing Mo, the source gas containing Mo contains Mo, C, and a halogen element, and has a Mo—C bond. A source gas or a source gas containing Mo and a halogen element can be used. Examples of source gas containing Mo and a halogen element include source gas containing Mo and chloro group such as molybdenum pentachloride (MoCl ₅ ), and source gas containing Mo and fluoro group such as molybdenum pentafluoride (MoF ₅ ). Can be used. As the oxidizing gas, nitriding gas, amine-based catalyst gas, and oxygen-free gas, the same gas as that in the above-described embodiment can be used. The processing conditions at this time can be set to the same processing conditions as in the above-described embodiment, for example.

That is, the present invention can be suitably applied when forming a thin film containing a predetermined element such as a semiconductor element or a metal element. The reforming step of the present invention is a thin film containing moisture (H ₂ O) and chlorine (Cl) as the first impurities and a hydrocarbon compound (C _x H _y- based impurities) as the second impurities. If it exists, it can apply not only to the above-mentioned film-forming method and film | membrane type but widely.

  The process recipes (programs describing the processing procedures and processing conditions) used to form these various thin films are the contents of the substrate processing (film type, composition ratio, film quality, film thickness, source gas, oxidation gas to be formed) It is preferable to prepare individually (a plurality of gas), catalyst gas, oxygen-free gas type, etc.). And when starting a substrate processing, it is preferable to select a suitable process recipe suitably from several process recipes according to the content of a substrate processing. Specifically, the substrate processing apparatus includes a plurality of process recipes individually prepared according to the contents of the substrate processing via an electric communication line or a recording medium (external storage device 123) on which the process recipe is recorded. It is preferable to store (install) in the storage device 121c in advance. When starting the substrate processing, the CPU 121a included in the substrate processing apparatus appropriately selects an appropriate process recipe from a plurality of process recipes stored in the storage device 121c according to the content of the substrate processing. Is preferred. With this configuration, thin films with various film types, composition ratios, film qualities, and film thicknesses can be formed for general use with good reproducibility using a single substrate processing apparatus. Further, it is possible to reduce an operator's operation burden (such as an input burden of a processing procedure and a processing condition), and to quickly start substrate processing while avoiding an operation error.

  The above-described process recipe is not limited to the case of creating a new process. For example, an existing process recipe already installed in the substrate processing apparatus may be changed. When changing the process recipe, the changed process recipe may be installed in the substrate processing apparatus via an electric communication line or a recording medium recording the process recipe. Further, an existing process recipe that has already been installed in the substrate processing apparatus may be directly changed by operating the input / output device 122 provided in the existing substrate processing apparatus.

  In the film forming sequence of the above-described embodiment and the like, the example in which the formation of the SiOC film, the SiO film, the laminated film, and the like is performed at room temperature has been described. In this case, it is not necessary to heat the processing chamber 201 with the heater 207, and the heater 207 may not be provided in the substrate processing apparatus. Thereby, the structure of the heating system of a substrate processing apparatus can be simplified, and a substrate processing apparatus can be made cheaper and a simple structure. In this case, the modification process of the SiOC film, the SiO film, the laminated film, and the like is performed in Ex-Situ in a processing chamber different from the processing chamber that performs the forming process of the SiOC film, the SiO film, the laminated film, and the like. .

  In the above-described embodiment and the like, an example in which the modification process (annealing process) of the SiOC film, the SiO film, the laminated film, or the like is performed by heating with the resistance heating type heater 207 has been described. The present invention is not limited to this form. For example, the above-described modification treatment may be performed by irradiation with plasma, ultraviolet rays, microwaves, or the like. That is, the above-described reforming process may be performed not only using heat transfer from the heater 207 but also using an activating means other than heat, such as plasma or electromagnetic waves. Even in these cases, the same effects as those of the above-described embodiment can be obtained.

When performing the above-described modification treatment by irradiating with plasma, for example, a capacitively coupled plasma generator, an inductively coupled plasma generator, an electron cyclotron resonator, a surface wave plasma generator, a helicon wave plasma generator, etc. It can be used as an activating means instead of. In addition, these devices can be used in combination with the heater 207. Using these devices, for example, gas such as He, Ar, N ₂ or the like is converted into plasma in the processing chamber 201 or in the buffer chamber provided outside the processing chamber 201, and the obtained plasma, that is, charged particles and neutral particles The above modification process can be performed by irradiating the wafer 200 in the process chamber 201 with a quasi-neutral gas that performs collective behavior.

  When the above-described reforming treatment is performed by irradiating ultraviolet rays, for example, a deuterium lamp, a helium lamp, a carbon arc lamp, a BRV light source, an excimer lamp, a mercury lamp, or the like is used as an activating means in place of the heater 207. it can. In addition, these devices can be used in combination with the heater 207. For example, the above-described modification process can be performed by irradiating the wafer 200 in the processing chamber 201 with vacuum ultraviolet rays having a wavelength of 10 nm to 200 nm from these light sources.

  When performing the above-described modification treatment by irradiating microwaves, for example, a microwave generator that generates an electromagnetic wave having a wavelength of 100 μm to 1 m and a frequency of 3 THz to 300 MHz can be used as an activating means instead of the heater 207. . In addition, these devices can be used in combination with the heater 207. Microwave of the above-described wavelength is irradiated to the wafer 200 in the processing chamber 201 and induced by acting on electronic polarization or ion polarization in a dielectric film such as a SiOC film, a SiO film, or a laminated film. By causing heating, the above-described reforming treatment can be performed.

  Also in these cases, the processing conditions can be the same processing conditions as those in the above-described embodiments and modifications, for example.

  In the above-described embodiment and the like, an example in which a thin film is formed using a batch-type substrate processing apparatus that processes a plurality of substrates at a time has been described. The present invention is not limited to this, and can also be suitably applied to the case where a thin film is formed using a single-wafer type substrate processing apparatus that processes one or several substrates at a time. In the above-described embodiment, an example in which a thin film is formed using a substrate processing apparatus having a hot wall type processing furnace has been described. The present invention is not limited to this, and can also be suitably applied to the case where a thin film is formed using a substrate processing apparatus having a cold wall type processing furnace. The processing conditions in these cases can be the same processing conditions as in the above-described embodiment, for example.

  Each above-mentioned embodiment and each modification can be used combining suitably. Further, the processing conditions at this time can be the same processing conditions as in the above-described embodiment, for example.

(First embodiment)
As an example of the present invention, the substrate processing apparatus in the above-described embodiment is used, and a SiOC film is formed on the wafer by the film-forming sequence in FIG. The various characteristics of each SiOC film were evaluated. The film forming process and the reforming process were performed in different processing chambers, that is, Ex-situ. As the modification treatment, only the second heat treatment was performed without performing the first heat treatment. BTCSM gas was used as the source gas, H ₂ O gas was used as the oxidizing gas, pyridine gas was used as the catalyst gas, and N ₂ gas was used as the heat treatment gas during the reforming process. The processing conditions were the same as those in the above embodiment.

  FIG. 11 is a graph showing the evaluation results of this example. (A) shows the relative dielectric constant of the SiOC film before and after the heat treatment, and (b) shows the wet etching rate (WER) of the SiOC film before and after the heat treatment. (C) shows the temperature dependence of the heat treatment of WER of the SiOC film.

The horizontal axis of the graph of FIG. 11A shows the processing state of the SiOC film, and in order from the left, an example of the SiOC film that has been formed with the wafer temperature set to 60 ° C. and not subjected to heat treatment (60 ° C. as depo) shows an example of an SiOC film (600 ° C., 30 min N ₂ annealing) which was deposited at a wafer temperature of 60 ° C. and then heat-treated for 30 minutes under an N ₂ gas atmosphere at a wafer temperature of 600 ° C. . The vertical axis of the graph represents the relative dielectric constant (k value) of the SiOC film. The relative dielectric constant of the SiOC film is the ratio ε _r = ε / ε ₀ of the dielectric constant ε of the SiOC film to the dielectric constant ε ₀ of vacuum.

  As can be seen from FIG. 11A, the relative dielectric constant of the SiOC film before heat treatment in this example is 7.76. Further, according to another evaluation performed by the present inventors, the relative dielectric constant of the SiOC film formed at a relatively high temperature was about 4.5. It can be seen that the relative dielectric constant of the SiOC film in this example is higher than that before the heat treatment. On the other hand, the relative dielectric constant of the SiOC film after heat treatment in this example is 3.58, and the relative dielectric constant (about 4.5) of the SiOC film formed at a relatively high temperature described above, It can be seen that the relative dielectric constant (about 3.9) of the thermal oxide film is significantly lower. This is because the material that increases the dielectric constant, such as moisture and impurities such as Cl, contained in the SiOC film formed under the low temperature condition has been removed from the SiOC film by the heat treatment of the SiOC film, and the SiOC film. The main factor is considered to be that the membrane is porous.

The horizontal axis of the graph of FIG. 11B is the same as that of FIG. 11A, and shows “60 ° C. as depo” and “600 ° C. 30 min N ₂ annual”, respectively, from the left. In addition, the vertical axis of the graph represents WER [a. u. ] Is shown. Here, WER is the etching depth per unit time, and the smaller the value, the higher the resistance to HF (etching resistance).

  It can be seen that the SiOC film before the heat treatment in FIG. 11B has relatively good etching resistance from its WER. In other evaluations, it has been confirmed that the WER of this SiOC film is lower than the WER of the SiO film formed by the present inventors under low temperature conditions. Further, according to FIG. 11B, it can be seen that the WER of the SiOC film after the heat treatment is a value of 1/8 or less of the WER of the SiOC film before the heat treatment. This corresponds to a value lower than the WER of a normal thermal oxide film. That is, it can be seen that the heat resistance of the SiOC film can reduce the impurities in the SiOC film and improve the etching resistance.

The horizontal axis of the graph of FIG. 11C shows the temperature condition at the time of heat treatment of the SiOC film which was formed at a wafer temperature of 60 ° C. and then heat-treated for 30 minutes in an N ₂ gas atmosphere. Examples of 200 ° C., 300 ° C., 500 ° C., 600 ° C., and 630 ° C. are shown in order. In addition, the vertical axis of the graph represents the WER [a. u. ] Is shown.

  As can be seen from FIG. 11C, when the temperature during the heat treatment is 200 ° C., the effect of the reforming treatment can be sufficiently obtained from the WER. Further, according to FIG. 11C, it can be seen that the WER when the temperature during the heat treatment is 300 ° C. is about half of the WER when the temperature during the heat treatment is 200 ° C., and a better result can be obtained. . Moreover, when the temperature at the time of heat processing is 500 degreeC, the fall of WER becomes more remarkable, and it turns out that a result comparable with the result higher than this, ie, 600 degreeC and 630 degreeC, is obtained. It can be seen that the WER when the temperature during the heat treatment is 500 ° C., 600 ° C., and 630 ° C. is less than about 1/10 of the WER when the temperature during the heat treatment is 200 ° C. From this, it can be seen that a remarkable effect of improving the etching resistance can be obtained by setting the temperature during the heat treatment to at least 500 ° C. or more. Further, it can be seen that the WER decreases further at 630 ° C., although the decrease in WER decreases at a temperature of 500 ° C. or higher. The WER at 630 ° C. is about 70% of the WER at 500 ° C. Therefore, it can be predicted that by setting the temperature during the heat treatment to 630 ° C. or higher, further excellent etching resistance can be obtained. Thus, it can be seen that the effect of reducing the WER of the SiOC film is further increased by increasing the temperature during the heat treatment.

(Second embodiment)
As an example of the present invention, the substrate processing apparatus in the above-described embodiment is used, and a SiOC film is formed on the wafer by the film-forming sequence in FIG. Went. The film forming process and the reforming process were performed in different processing chambers, that is, Ex-situ.

  Here, as the reforming treatment, both the first heat treatment and the second heat treatment are performed in the annealing sequence shown in FIG. 14A (sample 1), and the first heat treatment is not performed and the second heat treatment is performed. A sample (sample 2) subjected to only heat treatment was prepared. And various characteristics of the SiOC film of each sample were evaluated.

When preparing each sample, BTCSM gas was used as the source gas, H ₂ O gas was used as the oxidizing gas, pyridine gas was used as the catalyst gas, and N ₂ gas was used as the heat treatment gas during the reforming process. The wafer temperature (first temperature) in the first heat treatment of Sample 1 was 450 ° C., and the wafer temperature (second temperature) in the second heat treatment was 600 ° C. The other processing conditions were the same as those in the above embodiment.

  FIG. 13 is a diagram showing the evaluation results of this example. Various characteristics (WER, shrink rate (shrinkage rate), k value (relative permittivity)) of the SiOC film of sample 1 and the SiOC film of sample 2 are shown. The comparison is summarized in a table.

According to FIG. 13, the WER of the SiOC film of sample 1 is 1/17 or less of the WER of the SiOC film of sample 2, and the WER of the SiOC film of sample 1 is much higher than the WER of the SiOC film of sample 2. I understand that it is small. It can also be seen that the WER of the SiOC film of sample 2 is relatively small, and the SiOC film of sample 2 also has a relatively good etching resistance. That is, the WER of the SiOC film of sample 1 is much smaller than the small WER (WER of the SiOC film of sample 2), and the SiOC film of sample 1 has a good etching resistance (etching resistance of the SiOC film of sample 2). It can be seen that the etching resistance is even higher than that. In the case of the SiOC film of sample 2, impurities such as moisture and Cl contained in the SiOC film were removed from the SiOC film by the second heat treatment, whereas in the case of the SiOC film of sample 1 Since the first heat treatment and the second heat treatment are performed stepwise, in addition to impurities such as moisture and Cl contained in the SiOC film, C _x H _y- based impurities are sufficiently contained in the SiOC film. This is considered to be the result of the removal.

  Further, according to FIG. 13, the shrinkage rate of the SiOC film of sample 1 is about 9/10 of the shrinkage rate of the SiOC film of sample 2, and the shrinkage rate of the SiOC film of sample 1 is equal to that of the SiOC film of sample 2. It can be seen that it is smaller than the shrink rate. Here, the shrinkage ratio indicates the shrinkage rate of the SiOC film after the modification process with respect to the SiOC film before the modification process, that is, the rate at which the SiOC film shrinks due to the modification process. That is, it can be seen that the SiOC film of sample 1 is not shrunk by the modification process than the SiOC film of sample 2. In other words, it can be seen that the SiOC film of sample 2 is contracted by the modification process more than the SiOC film of sample 1.

  The shrinkage rate of the SiOC film of sample 1 is small because the SiOC film of sample 1 is subjected to the first heat treatment and the second heat treatment in steps, that is, the heat treatment with different temperatures is performed in two steps. This is considered to be because the oxidation of the SiOC film due to moisture or Cl desorbed from the SiOC film can be suppressed, and the film shrinkage rate can be suppressed. In addition, the shrinkage rate of the SiOC film of sample 2 is large because the SiOC film of sample 2 is subjected only to the second heat treatment without being subjected to the first heat treatment, that is, compared in one step. It is considered that the heat treatment is performed at a relatively high temperature, whereby the SiOC film is oxidized by moisture or Cl desorbed from the SiOC film, and the SiOC film is easily contracted.

  Further, according to FIG. 13, it can be seen that the relative dielectric constant (2.68) of the SiOC film of Sample 1 is smaller than the relative dielectric constant (3.58) of the SiOC film of Sample 2. In addition, the relative dielectric constant (3.58) of the SiOC film of sample 2 is a dielectric constant significantly lower than that of a general thermal oxide film (about 3.9). It can be seen that the relative dielectric constant (2.68) is a lower dielectric constant than that.

The relative permittivity of the SiOC film of Sample 2 was significantly lower than that of a general thermal oxide film because the second heat treatment performed on the SiOC film caused moisture contained in the SiOC film. It is considered that the main factors are that a substance that increases the dielectric constant such as impurities such as Cl is removed from the SiOC film and that the SiOC film is made porous. The relative permittivity of the SiOC film of sample 1 was significantly lower than the relative permittivity of a general thermal oxide film and the relative permittivity of the SiOC film of sample 2. In addition to substances that increase the dielectric constant such as impurities such as moisture and Cl contained in the SiOC film by the heat treatment of step 2, ie, heat treatment performed stepwise at different temperatures, impurities of C _x H _y system It is considered that the main factors are that a substance that increases the dielectric constant, such as, has been sufficiently removed from the SiOC film and that the SiOC film has become more porous.

(Third embodiment)
As an example of the present invention, the substrate processing apparatus in the above-described embodiment is used, and a SiOC film is formed on the wafer by the film-forming sequence in FIG. Went. The film forming process and the reforming process were performed in different processing chambers, that is, Ex-situ.

Here, after forming the film at a wafer temperature of 60 ° C., a sample (sample 1) subjected to heat treatment in an atmosphere of N ₂ gas at a wafer temperature of 100 ° C. was formed at a wafer temperature of 60 ° C. After that, as a modification process, a sample 2 that was heat-treated at a wafer temperature of 200 ° C. in an atmosphere of N ₂ gas, and a film was formed at a wafer temperature of 60 ° C. 15 and the sample 3 in which the second heat treatment is performed in the annealing sequence of FIG. 15 and the wafer temperature is 60 ° C., and then the first heat treatment and the second heat treatment are performed as a modification treatment in FIG. Samples (samples 4 to 6) performed in the annealing sequence were prepared. And WER of the SiOC film | membrane of each sample was evaluated.

When preparing each sample, BTCSM gas was used as the source gas, H ₂ O gas was used as the oxidizing gas, pyridine gas was used as the catalyst gas, and N ₂ gas was used as the heat treatment gas during the SiOC film modification treatment. . The wafer temperature (first temperature, second temperature) in the first heat treatment and the second heat treatment of Sample 3 was set to 300 ° C. The wafer temperature (first temperature) in the first heat treatment of Samples 4 to 6 was 450 ° C., respectively. The wafer temperatures (second temperatures) in the second heat treatment of Samples 4 to 6 were 500 ° C., 600 ° C., and 630 ° C., respectively. Other conditions, that is, the time for maintaining the first temperature and the second temperature, the time required for temperature increase and decrease, and the like are as shown in the table of FIG. The other processing conditions were the same as those in the above embodiment.

  FIG. 16A is a graph showing WER of samples 1 to 6, and FIG. 16B is a table comparing the heat treatment conditions of the annealing sequences of samples 1 to 6. In FIG. 16A, the horizontal axis represents each sample, and the vertical axis represents the WER [Å / min] of the SiOC film with 1% HF aqueous solution.

FIG. 16A shows that the SiOC films of Samples 2 to 6 have much lower WER than the SiOC film of Sample 1, that is, the etching resistance is extremely good. In particular, it can be seen that in Samples 3 to 6 in which the first temperature and the second temperature are set to temperatures within the ranges exemplified in the above-described embodiment, the WER is further reduced and the etching resistance is further improved. The samples 4 to 6 in which the second temperature is set higher than the first temperature are smaller in WER than the sample 3 in which the second temperature is set to the same temperature as the first temperature. It can be seen that the etching resistance becomes better. This is because the first heat treatment and the second heat treatment are performed within the condition range described in the above-described embodiment, and in addition to the first impurities such as moisture and Cl contained in the SiOC film, C _{the x} H _y type second impurity is sufficiently removed from the SiOC film is considered a major factor.

(Fourth embodiment)
As an example of the present invention, the substrate processing apparatus in the above-described embodiment is used, and a SiOC film is formed on the wafer by the film-forming sequence in FIG. Went. The film forming process and the reforming process were performed in different processing chambers, that is, Ex-situ.

  Here, an as-deposited sample (sample 1) in which the SiOC film is formed at a wafer temperature of 60 ° C., and the first heat treatment and the second heat treatment are shown after the SiOC film is formed at a wafer temperature of 60 ° C. After forming the SiOC film with the sample (samples 2 to 4) having the annealing sequence of 15 and the wafer temperature of 60 ° C., the first heat treatment and the second heat treatment are performed by the annealing sequence of FIG. Samples (Samples 5 to 8) were prepared. Then, the relative dielectric constant of the SiOC film of each sample was evaluated.

When preparing samples 1 to 8, BTCSM gas is used as the source gas, H ₂ O gas is used as the oxidizing gas, pyridine gas is used as the catalyst gas, and N ₂ gas is used as the heat treatment gas during the SiOC film reforming process. Using. The wafer temperatures (= first temperature = second temperature) in the first heat treatment and the second heat treatment of Samples 2 to 4 were 300 ° C., 400 ° C., and 600 ° C., respectively. The wafer temperature (first temperature) in the first heat treatment of Sample 5 was 60 ° C., and the wafer temperature (second temperature) in the second heat treatment was 200 ° C. The wafer temperature (first temperature) in the first heat treatment of Samples 6 to 8 is 450 ° C., and the wafer temperature (second temperature) in the second heat treatment is 500 ° C., 630 ° C., and 700 ° C., respectively. did. The other processing conditions were the same as those in the above embodiment.

  As a reference example, an SiO film is formed on a wafer by a film forming sequence in which a supply of a source gas and a catalyst gas and an oxidizing gas and a catalyst gas are alternately supplied a predetermined number of times, and then the SiO film is modified. Processed. The film forming process and the reforming process were performed in different processing chambers, that is, Ex-situ.

  Here, an as-deposited sample (sample 9) in which the SiO film is formed at a wafer temperature of 60 ° C., and a first heat treatment is performed as a modification process after the SiO film is formed at a wafer temperature of 60 ° C. First, a sample (sample 10) subjected to only the second heat treatment was prepared. Then, the relative dielectric constant of the SiO film of each sample was evaluated.

When preparing Samples 9 and 10, HCDS gas was used as the source gas, H ₂ O gas was used as the oxidizing gas, pyridine gas was used as the catalyst gas, and N ₂ gas was used as the heat treatment gas during the reforming process. . The wafer temperature (second temperature) in the second heat treatment of sample 10 was set to 600 ° C. The other processing conditions were the same as those in the above embodiment.

  FIG. 17 is a graph showing the relative permittivity (k value) of Samples 1 to 10, where the horizontal axis indicates the wafer temperature (° C.) in the second heat treatment, and the vertical axis indicates the relative permittivity. In this figure, for convenience, samples 1 to 10 are denoted as S1 to S10, respectively.

According to FIG. 17, it can be seen that the SiOC films of Samples 2 to 8 have a lower relative dielectric constant than the SiOC film of Sample 1 and the SiO film of Sample 9. In particular, it can be seen that in samples 3 to 4, 6 to 8 in which the first temperature and the second temperature are set to temperatures within the range exemplified in the above-described embodiment, the relative dielectric constant is further reduced. It can also be seen that the SiOC films of Samples 3-4 and 6-8 have a relative dielectric constant smaller than that of Sample 10. It can also be seen that the SiOC films of Samples 6 to 8 have a relative dielectric constant smaller than 3. These are the impurities such as moisture and Cl contained in the SiOC film formed under the low temperature condition by performing the first heat treatment and the second heat treatment within the condition range described in the above embodiment. It is considered that the main factors are that the substance that increases the dielectric constant, such as impurities and C _x H _y impurities, has been removed from the SiOC film and that the SiOC film has become porous.

<Preferred embodiment of the present invention>
Hereinafter, preferred embodiments of the present invention will be additionally described.

(Appendix 1)
According to one aspect of the invention,
Forming a thin film on the substrate;
The first impurity containing moisture (H ₂ O) and chlorine (Cl) is removed from the thin film by heat-treating the thin film at a first temperature higher than the temperature of the substrate in the step of forming the thin film. And a process of
By heat-treating the thin film at a second temperature that is equal to or higher than the first temperature, a hydrocarbon compound (a C _x H _y- based impurity) is contained in the thin film after the heat treatment at the first temperature. Removing the two impurities;
And a substrate processing method are provided.

(Appendix 2)
The method according to appendix 1, preferably,
The step of removing the first impurity includes at least a part of a period in which the temperature of the substrate is raised to the first temperature.

(Appendix 3)
The method according to appendix 1 or 2, preferably,
The step of removing the first impurity includes a period in which the temperature of the substrate is kept constant at the first temperature.

(Appendix 4)
The method according to any one of appendices 1 to 3, preferably,
The second temperature is higher than the first temperature. In addition, the step of removing the second impurity includes at least a part of a period in which the temperature of the substrate is raised to the second temperature.

(Appendix 5)
The method according to any one of appendices 1 to 4, preferably,
The step of removing the second impurity includes a period in which the temperature of the substrate is kept constant at the second temperature.

(Appendix 6)
The method according to any one of appendices 1 to 5, preferably,
The step of removing the second impurity includes at least a part of a period in which the temperature of the substrate is lowered from the second temperature.

(Appendix 7)
The method according to any one of appendices 1 to 3, preferably,
The second temperature is the same temperature (the same temperature) as the first temperature. Further, the step of removing the second impurity includes a period of maintaining the temperature of the substrate at the first temperature.

(Appendix 8)
The method according to any one of appendices 1 to 7, preferably,
The first temperature is set to a temperature at which the thin film is not oxidized by the first impurity when the first impurity is removed from the thin film. Further preferably, when the first impurity is removed from the thin film, the first impurity and an impurity different from the first impurity contained in the thin film are formed. Let the temperature not react. Preferably, the first temperature is a temperature at which the first impurity and the second impurity contained in the thin film do not react when removing the first impurity from the thin film. And

(Appendix 9)
The method according to any one of appendices 1 to 8, preferably,
The first temperature is set to a temperature within a range of 300 ° C. or higher and 450 ° C. or lower. More preferably, the first temperature is a temperature within a range of 300 ° C. or higher and 400 ° C. or lower, and more preferably a temperature within a range of 300 ° C. or higher and 350 ° C. or lower.

(Appendix 10)
The method according to any one of appendices 1 to 9, preferably,
The second temperature is set to a temperature within a range of 300 ° C. or higher and 900 ° C. or lower. More preferably, the second temperature is a temperature within a range of 350 ° C. or higher and 700 ° C. or lower, more preferably a temperature within a range of 400 ° C. or higher and 700 ° C. or lower, and further preferably 450 ° C. or higher and 600 ° C. or lower. The temperature is within the range.

(Appendix 11)
The method according to any one of appendices 1 to 10, preferably,
The thin film includes a predetermined element, oxygen, and carbon.

(Appendix 12)
The method according to appendix 11, preferably,
In the step of forming the thin film,
Supplying a source gas containing the predetermined element, carbon and a halogen element to the substrate, and having a chemical bond between the predetermined element and carbon;
Supplying an oxidizing gas to the substrate;
Supplying a catalyst gas to the substrate;
A cycle including is performed a predetermined number of times.

(Appendix 13)
The method according to appendix 12, preferably,
In the step of forming the thin film, the temperature of the substrate is set to a temperature of room temperature to 150 ° C. Preferably, the temperature of the substrate is a temperature of room temperature to 100 ° C., more preferably a temperature of 50 ° C. to 100 ° C.

(Appendix 14)
The method according to appendix 12 or 13, preferably,
The predetermined element includes silicon (Si), and the source gas has at least one selected from the group consisting of Si—C bonds, Si—C—Si bonds, and Si—C—C—Si bonds.

(Appendix 15)
The method according to any one of appendices 1 to 14, preferably:
In the step of removing the first impurity and the step of removing the second impurity, the heat treatment is performed in an oxygen-free atmosphere by supplying an oxygen-free gas to the substrate. In the step of removing the first impurity and the step of removing the second impurity, the heat treatment is performed in an inert gas atmosphere by supplying an inert gas to the substrate.

(Appendix 16)
The method according to any one of appendices 1 to 15, preferably,
The step of forming the thin film and the step of heat-treating the thin film (the step of removing the first impurity and the step of removing the second impurity) are performed in the same processing chamber or in different processing chambers.

(Appendix 17)
According to another aspect of the invention,
A processing chamber for accommodating the substrate;
A processing gas supply system for supplying a processing gas for forming a thin film into the processing chamber;
A heater for heating the substrate in the processing chamber;
The process gas is supplied to the substrate in the processing chamber to form a thin film on the substrate, and the thin film is heat-treated at a first temperature higher than the temperature of the substrate in the process of forming the thin film. By removing the first impurity containing moisture (H ₂ O) and chlorine (Cl) from the thin film, and heat-treating the thin film at a second temperature equal to or higher than the first temperature, Removing the second impurity containing a hydrocarbon compound (C _x H _y- based impurity) from the thin film after the heat treatment at the first temperature, and performing the process gas supply system and A controller configured to control the heater;
A substrate processing apparatus is provided.

(Appendix 18)
According to yet another aspect of the invention,
A substrate processing system comprising: a first substrate processing unit that forms a thin film on a substrate; and a second substrate processing unit that heat-treats the thin film,
The first substrate processing unit includes:
A first processing chamber for accommodating a substrate;
A processing gas supply system for supplying a processing gas for forming a thin film into the first processing chamber;
A first control unit configured to control the process gas supply system so as to perform a process of supplying the process gas to the substrate in the first process chamber to form a thin film on the substrate; Have
The second substrate processing unit includes:
A second processing chamber for accommodating a substrate;
A heater for heating the substrate in the second processing chamber;
By heat-treating the thin film at a first temperature higher than the temperature of the substrate in the process of forming the thin film in a state where the substrate on which the thin film is formed is accommodated in the second processing chamber, Removing the first impurities including moisture (H ₂ O) and chlorine (Cl) from the substrate, and heat-treating the thin film at a second temperature that is equal to or higher than the first temperature. A second control configured to control the heater so as to perform a process of removing a second impurity containing a hydrocarbon compound (C _x H _y- based impurity) from the thin film after the heat treatment. A substrate processing system.

(Appendix 19)
According to yet another aspect of the invention,
A procedure for forming a thin film on a substrate in a processing chamber;
The first impurity containing moisture (H ₂ O) and chlorine (Cl) is removed from the thin film by heat-treating the thin film at a first temperature higher than the temperature of the substrate in the step of forming the thin film. And the steps to
By heat-treating the thin film at a second temperature that is equal to or higher than the first temperature, a hydrocarbon compound (a C _x H _y- based impurity) is contained in the thin film after the heat treatment at the first temperature. Removing the two impurities;
And a computer-readable recording medium on which the program is recorded are provided.

121 Controller (control unit)
200 wafer (substrate)
201 processing chamber 202 processing furnace 203 reaction tube 207 heater (heating means)
209 Manifold 231 Exhaust pipes 232a to 232l Gas supply pipe 244 APC valve (pressure adjustment unit)

Claims (18)

A first temperature higher than the temperature of the substrate when a thin film containing a chemical bond between a predetermined element and oxygen, a first impurity containing moisture and chlorine, and a second impurity containing a hydrocarbon compound is formed on the substrate. Removing the first impurity from the thin film by heat-treating the thin film formed on the substrate at a temperature; and
Removing the second impurity from the thin film after the heat treatment at the first temperature by heat-treating the thin film at a second temperature higher than the first temperature;
A method for manufacturing a semiconductor device comprising:   2. The method of manufacturing a semiconductor device according to claim 1, wherein the first temperature is a temperature at which the thin film is not oxidized by the first impurity when the first impurity is removed from the thin film.   The first temperature is a temperature at which the first impurity and an impurity different from the first impurity contained in the thin film do not react when the first impurity is removed from the thin film. A method for manufacturing a semiconductor device according to claim 1 or 2. The first temperature is set to a temperature at which the first impurity and the second impurity contained in the thin film do not react when the first impurity is removed from the thin film. the method of manufacturing a semiconductor device of any one of 1-3. The method of manufacturing a semiconductor device according to any one of claims 1 to 4, said first temperature, a temperature in the range of 300 ° C. or higher 450 ° C. or less. The method of manufacturing a semiconductor device according to any one of claims 1 to 5, wherein the second temperature, a temperature within the range of 300 ° C. or higher 900 ° C. or less. The method of manufacturing a semiconductor device according to any one of claims 1 to 6, the temperature of the substrate is 0.99 ° C. or less of a temperature above room temperature when forming the thin film. The thin film may further predetermined element and method for manufacturing a semiconductor device according to any one of claims 1 to 7 including a chemical bond with carbon. It said first impurity through the steps of removing step and the second impurity removing method of manufacturing a semiconductor device according to any one of claims 1 to 8 for a porous structure the thin film. The thin film before the step of removing the first impurity is porous, and the thin film is further removed by performing the step of removing the first impurity and the step of removing the second impurity. the method of manufacturing a semiconductor device according to any one of claims 1 to 9 for a porous structure. The method of manufacturing a semiconductor device according to claim 1, wherein the thin film includes an oxide film. The method of manufacturing a semiconductor device according to claim 1, wherein the thin film includes an oxycarbide film. The thin film manufacturing method of a semiconductor device according to any one of claims 1 to 12 comprising a laminated film and the oxide film and oxycarbide film are laminated. Predetermined element manufacturing method of a semiconductor device according to any one of claims 1 to 13 including a semiconductor element or a metal element. A first temperature higher than the temperature of the substrate when a thin film containing a chemical bond between a predetermined element and oxygen, a first impurity containing moisture and chlorine, and a second impurity containing a hydrocarbon compound is formed on the substrate. Removing the first impurity from the thin film by heat-treating the thin film formed on the substrate at a temperature; and
Removing the second impurity from the thin film after the heat treatment at the first temperature by heat-treating the thin film at a second temperature higher than the first temperature;
A substrate processing method. A processing chamber for accommodating the substrate;
A heater for heating the substrate in the processing chamber;
A first temperature higher than the temperature of the substrate when a thin film containing a chemical bond between a predetermined element and oxygen, a first impurity containing moisture and chlorine, and a second impurity containing a hydrocarbon compound is formed on the substrate. Heat treating the thin film formed on the substrate at a temperature to remove the first impurity from the thin film; and heat treating the thin film at a second temperature higher than the first temperature. And a control configured to control the heater so that the process of removing the second impurity from the thin film after the heat treatment at the first temperature is performed in the process chamber. And
A substrate processing apparatus. In the processing chamber of the substrate processing apparatus,
A first temperature higher than the temperature of the substrate when a thin film containing a chemical bond between a predetermined element and oxygen, a first impurity containing moisture and chlorine, and a second impurity containing a hydrocarbon compound is formed on the substrate. Removing the first impurity from the thin film by heat-treating the thin film formed on the substrate at a temperature; and
Removing the second impurity from the thin film after the heat treatment at the first temperature by heat-treating the thin film at a second temperature higher than the first temperature;
Accordingly to a computer program to be executed by the substrate processing apparatus. In the processing chamber of the substrate processing apparatus,
A first temperature higher than the temperature of the substrate when a thin film containing a chemical bond between a predetermined element and oxygen, a first impurity containing moisture and chlorine, and a second impurity containing a hydrocarbon compound is formed on the substrate. Removing the first impurity from the thin film by heat-treating the thin film formed on the substrate at a temperature; and
Removing the second impurity from the thin film after the heat treatment at the first temperature by heat-treating the thin film at a second temperature higher than the first temperature;
A computer readable recording medium storing a program for executing the thus the substrate processing device to a computer.