JP2019186409A - Deposition device, and deposition method - Google Patents

Abstract

To provide a technique for improving the in-plane and the inter-surface uniformity of a film deposited on a substrate, with high productivity, in a deposition device for depositing a film composed of a film substance, by supplying deposition gases mutually reacting and becoming the film substance to the substrate.SOLUTION: A turntable 2 for revolving a substrate W around a revolving shaft 22 is provided in a processing container 10, and the substrate is placed on the turntable and heated. Furthermore, a gas supply nozzle 3 for supplying first deposition gas and second deposition gas is provided so as to supply the gas in the radial direction of the turntable, and an exhaust duct 4 is provided at a position opposite to the discharge direction of the deposition gas from the gas supply nozzle across the turntable.SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to a film forming apparatus and a film forming method.

  In a manufacturing process of a semiconductor device, a film forming process may be performed by reacting a processing gas supplied to a substrate such as a semiconductor wafer (hereinafter referred to as “wafer”).

  As an example of the film forming process, for example, in Patent Document 1, vapors of first and second reactants including organic reactants that react with each other are supplied to a substrate supported by a substrate support by horizontal flow. An example of forming an organic film is described.

JP 2017-76784 A

  The present disclosure relates to a film forming apparatus that forms a film made of a film material by supplying film forming gases that react with each other to the substrate to form a film made of the film material. Provided is a technique for improving the in-plane and inter-plane uniformity of film thickness.

A film forming apparatus of the present disclosure includes a processing container in which a vacuum atmosphere is formed,
A rotary table provided in the processing container, wherein a substrate placement area for placing a plurality of substrates is formed on one side thereof, and provided with a rotation mechanism for revolving the substrate placement area around a rotation axis. When,
A heating mechanism for heating the substrate placed in the substrate placement region;
A first film-forming gas and a second film-forming gas which are provided in the processing container and are adsorbed on the surface of the substrate heated by the heating mechanism and react with each other to form a film material. A gas supply unit that supplies the gas toward the radial direction of the rotary table;
And an exhaust unit provided at a position opposite to a direction in which the film forming gas is discharged from the gas supply unit with the rotary table interposed therebetween.

  According to the present disclosure, in a film forming apparatus that forms a film made of a film material by supplying film forming gases that react with each other to the substrate to form a film material, the productivity is high and the film is formed on the substrate. It is possible to provide a technique for improving the in-plane and inter-surface uniformity of the film thickness.

It is a reaction diagram showing a process in which polyimide concerning an embodiment of this indication produces. It is a vertical side view of the film-forming apparatus which concerns on embodiment of this indication. It is a cross-sectional top view of the said film-forming apparatus. It is explanatory drawing which shows the 1st example of the supply sequence of the gas in the said film-forming apparatus. It is explanatory drawing which shows the 2nd example of the said gas supply sequence. It is explanatory drawing which shows the 3rd example of the said gas supply sequence. It is explanatory drawing which concerns on the mechanism in which the adsorption amount of the film-forming gas adsorb | sucked to a wafer changes. It is explanatory drawing which shows the view of the setting of the partial pressure of the film-forming gas in the said film-forming apparatus, and the heating temperature of a wafer. It is a vertical side view explaining the flow of the film-forming gas in the film-forming apparatus. It is a cross-sectional top view explaining the flow of the film-forming gas in the said film-forming apparatus. It is a 1st explanatory view showing an operation of the film deposition system. It is the 2nd explanatory view showing an operation of the film deposition system. It is a partial vertical side view which shows the other example of the to-be-collided member in embodiment. It is explanatory drawing which shows the 1st example of the film-forming gas which concerns on embodiment. It is explanatory drawing which shows the 2nd example of the said film-forming gas. It is explanatory drawing which shows the 3rd example of the film-forming gas. It is a vertical side view which shows the film-forming apparatus used for the preliminary test. It is a characteristic view which shows the film thickness of the film | membrane formed with respect to the distance from the gas supply nozzle for every temperature in a preliminary test.

A film forming apparatus according to one embodiment will be described. The film forming apparatus supplies a first film forming gas containing a first monomer that reacts with each other toward a wafer as a substrate and a second film forming gas containing a second monomer, A film forming process for forming a film made of a film material of a reactant on the surface is performed. In an embodiment, a bifunctional acid anhydride such as PMDA (C ₁₀ H ₂ O ₆ : pyromellitic anhydride) is used as the first monomer and a bifunctional amine such as ODA ( C ₁₂ H ₁₂ N ₂ O: 4,4′-diaminodiphenyl ether) is used to produce a film material made of polyimide. There is no particular limitation on whether PMDA or ODA is set as the first monomer (first film forming gas) or the second monomer (second film forming gas), and PMDA is used as the second monomer. ODA may be the first monomer.

  The synthesis of polyimide will be described. As shown in FIG. 1, PMDA is specifically a functional group consisting of a five-membered ring in which four carbon elements (C) and one oxygen element (O) are connected to each other by a single bond (single bond). Are provided, and another oxygen element is connected to the carbon element adjacent to the oxygen element by a double bond. The oxygen elements constituting the five-membered ring are arranged so as to face each other, and benzene sharing two carbon elements of each functional group is interposed between these two functional groups, so that the aromatic element is aromatic. It is a monomer. The 5-membered ring is for forming an imide ring.

In ODA, two amino groups (—NH ₂ ) having one nitrogen element (N) and two hydrogen elements (H) are arranged, and these nitrogen elements are at one end side and the other end of diphenyl ether. Each side is joined. In FIG. 1, description of carbon elements and hydrogen elements is omitted. Then, when these two types of monomers are mixed with each other, a precursor polyamic acid is generated. Thus, dehydration condensation occurs by heat treatment (heating) of the precursor, and a polyimide shown in the lower part of FIG. 1 is synthesized.

  Next, the configuration of the film forming apparatus will be described. As shown in FIGS. 2 and 3, the film forming apparatus includes a flat, generally circular vacuum container (processing container) 10 in which a vacuum atmosphere is formed. The vacuum container 10 includes a container main body 12 constituting a side wall and a bottom portion, and And the top plate 11. In the vacuum vessel 10, a circular turntable 2 is provided on which a plurality of wafers W having a diameter of 300 mm are horizontally placed. As shown in FIG. 2, on the upper surface (one surface side) of the turntable 2, a placement portion (substrate placement region) composed of six circular recesses along the circumferential direction (rotation direction) of the turntable 2. 24 is provided, and the wafer W is placed in the recess of each placement unit 24.

  A rotation mechanism 23 is provided at the center of the rear surface of the turntable 2 via a rotation shaft 22, and the turntable 2 moves upward about a vertical axis (center C of the turntable 2 shown in FIG. 2) during the film forming process. Rotate clockwise as viewed from the top. Therefore, the turntable 2 is configured to revolve the mounting portion 24 on which the wafer W is mounted around the rotation shaft 22. Reference numeral 20 in FIG. 2 denotes a case body that houses the rotating shaft 22 and the rotating mechanism 23. A purge gas supply pipe 72 for supplying nitrogen gas as a purge gas to the lower region of the turntable 2 is connected to the case body 20.

  As shown in FIG. 2, a plurality of heaters 7 serving as heating mechanisms are provided concentrically below the rotary table 2 at the bottom of the vacuum vessel 10, and the wafers W placed on the placement units 24 are heated. It is configured as follows. 2 is a covering member that covers the upper side of the heater 7. Further, as shown in FIG. 3, a transfer port 15 for the wafer W is opened on the side wall of the vacuum vessel 10 and is configured to be opened and closed by a gate valve 16. The position facing the transfer port 15 in the vacuum container 10 is a transfer position of the wafer W, and the wafer W passes through the mounting portion 24 below the turntable 2 at a position corresponding to the transfer position. A lifting / lowering pin for lifting and lifting mechanism (both not shown) are provided. The wafer W is transferred to a delivery position via a transfer port 15 by a substrate transfer mechanism (not shown) provided outside the vacuum vessel 10, and is moved to the placement unit 24 by the cooperative action of the substrate transfer mechanism and the lifting pins. Delivered.

A gas supply unit for supplying a first film forming gas containing PMDA and a second film forming gas containing ODA in the radial direction from the outer side of the turntable 2 to the side wall of the vacuum vessel 10. A gas supply nozzle 3 is provided. For example, the gas supply nozzle 3 is constituted by a straight pipe and extends in the lateral direction so as to penetrate the side wall of the vacuum container 10 (container body 12). Further, as shown in FIG. 3, the straight tubular gas supply nozzle 3 is arranged in the radial direction of the turntable 2 so that the end portion thereof is located on the outer side of the turntable 2. A gas discharge port (not shown) that opens toward the center C of the turntable 2 is provided at the end of the gas supply nozzle 3. With this configuration, the gas supply nozzle 3 can supply each film forming gas from the outer side of the mounting portion 24 toward the radial direction of the turntable 2.
Here, the gas supply nozzle 3 is not limited to the case where the opening of the gas discharge port is arranged so as to exactly match the radial direction of the turntable 2.
If the flow of the gas discharged from the gas discharge port can pass through the center of the turntable 2 and reach the exhaust duct 4 described later, the opening direction of the gas discharge port is deviated from the radial direction of the turntable. May be.

  A gas supply pipe 31 is connected to the base end of the gas supply nozzle 3 located outside the vacuum vessel 10. The gas supply pipe 31 is branched into two gas introduction pipes 53 and 63 on the upstream side. The upstream side of the gas introduction pipe 53 is connected to the PMDA vaporization unit 51 through the flow rate adjustment unit M1 and the valve V1 in this order.

In the PMDA vaporization unit 51, PMDA is stored in a solid state, and the PMDA vaporization unit 51 includes a heater (not shown) for heating the PMDA. One end of a carrier gas supply pipe 54 is connected to the PMDA vaporization section 51, and the other end of the carrier gas supply pipe 54 is supplied with N ₂ (nitrogen) gas through the valve V2 and the gas heating section 58 in this order. Connected to the source 52. With such a configuration, the N ₂ gas as the carrier gas is supplied to the PMDA vaporization unit 51 in a heated state, and the PMDA heated and vaporized in the PMDA vaporization unit 51 is mixed with the N ₂ gas. Then, it becomes a mixed gas and is introduced into the gas supply nozzle 3 as the first film forming gas.

Further, the downstream side of the gas heating section 58 and the upstream side of the valve V2 in the carrier gas supply pipe 54 are branched to form a gas supply pipe 55. The downstream end of the gas supply pipe 55 is introduced with a gas via the valve V3. The pipe 53 is connected downstream of the valve V1 and upstream of the flow rate adjusting unit M1. With such a configuration, when the first film forming gas is not supplied to the gas supply nozzle 3, the N ₂ gas heated by the gas heating unit 58 bypasses the PMDA vaporization unit 51 and is supplied to the gas supply nozzle 3. Can be introduced.

On the other hand, the other end of the gas introduction pipe 63 is connected to the ODA vaporization unit 61 through the flow rate adjustment unit M2 and the valve V4 in this order. In the ODA vaporization unit 61, ODA is stored in a liquid (or granular solid) state, and the ODA vaporization unit 61 includes a heater (not shown) for heating the ODA. Further, one end of a carrier gas supply pipe 64 is connected to the ODA vaporization section 61, and the other end of the carrier gas supply pipe 64 is connected to an N ₂ gas supply source 62 via a valve V5 and a gas heating section 68. ing. With such a configuration, the heated carrier gas N ₂ gas is supplied to the ODA vaporization unit 61 in a heated state, and the ODA heated and vaporized in the ODA vaporization unit 61 and the N ₂ gas are The gas is mixed to be a mixed gas and can be introduced into the gas supply nozzle 3 as the second film forming gas.

Further, the downstream side of the gas heating unit 68 and the upstream side of the valve V5 in the carrier gas supply pipe 64 are branched to form a gas supply pipe 65, and the downstream end of the gas supply pipe 65 introduces gas through the valve V6. The pipe 63 is connected to the downstream side of the valve V4 and the upstream side of the flow rate adjusting unit M2. With such a configuration, when the second film-forming gas is not supplied to the gas supply nozzle 3, the N ₂ gas heated by the gas heating unit 68 bypasses the ODA vaporization unit 61 and is supplied to the gas supply nozzle 3. Can be introduced.

  In order to prevent PMDA and ODA in the flowing film forming gas from being liquefied or adhered to the gas supply pipe 31 and the gas introduction pipes 53 and 63, for example, pipe heaters 32, 57, and 67 for heating the inside of the pipe. Are each provided around the tube. The temperature of the film forming gas discharged from the gas supply nozzle 3 is adjusted by the pipe heaters 32, 57 and 67. For convenience of illustration, the pipe heaters 32, 57, and 67 are shown in only a part of the pipe, but are provided, for example, in the whole pipe so as to prevent liquefaction.

The gas supply pipe 31 is connected to one end of a cleaning gas supply pipe 33 for supplying a cleaning gas. The other end of the cleaning gas supply pipe 33 is branched into two, and an N ₂ gas supply source 34 and an O ₂ (oxygen) gas supply source 35 are connected to each end. 2 and 3, V7 and V8 are valves.
With such a configuration, O ₂ gas diluted with N ₂ gas can be supplied as a cleaning gas into the vacuum vessel 10 through the gas supply nozzle 3.

  An exhaust duct (exhaust section) 4 is provided at a position facing the direction in which the film forming gas is discharged from the gas supply nozzle 3 with the center C of the turntable 2 interposed therebetween. The exhaust duct 4 is constituted by, for example, a rectangular tube that is curved in an arc shape along the peripheral shape of the vacuum vessel 10. When viewed in plan, the exhaust duct 4 is substantially centered on the extension line in the extending direction of the gas supply nozzle 3. It arrange | positions so that a part may be located. A plurality of exhaust ports 41 are formed side by side along the circumferential direction of the turntable 2 on the side surface of the exhaust duct 4 facing the turntable 2.

  Accordingly, the plurality of exhaust ports 41 are provided so as to spread in a direction intersecting with the direction in which the film forming gas is supplied from the gas supply nozzle 3 when viewed from the upper surface side. Further, one end of an exhaust pipe 42 is connected to the exhaust duct 4 from the outer surface side of the vacuum vessel 10, and a vacuum pump 43 is connected to the other end of the exhaust pipe 42. Thereby, the atmosphere in the vacuum vessel 10 is exhausted through the exhaust duct 4 and the exhaust port 41.

  Here, a protruding wall portion (member to be collided) 25 is provided on the periphery on the upper surface side of the turntable 2 so as to protrude upward along the circumferential direction of the turntable 2. The protruding wall portion 25 has a function of causing the film forming gas supplied from the gas supply nozzle 3 to collide and spreading it on the upper surface of the turntable 2. In this respect, the protruding wall portion 25 only needs to be provided between the outer edge of the moving region where the wafer W moves when the turntable 2 rotates and the gas supply nozzle 3. Therefore, it is not limited to the case where the protruding wall portion 25 is formed along the outer peripheral end position of the turntable 2 as in the protruding wall portion 25 illustrated in FIGS. A protruding wall portion may be arranged.

  Furthermore, two guide members 17 for guiding the direction in which the film forming gas spreads are provided at positions on both the left and right sides when viewed from the gas supply nozzle 3. Each guide member 17 has a base end portion connected to the inner wall surface of the container body 12 and is arranged so that both guide members 17 are separated from each other as viewed in a plan view. The guide member 17 prevents the film forming gas discharged from the gas supply nozzle 3 from flowing around the turntable 2 and forming a flow toward the exhaust duct 4, and reliably guides the film forming gas above the turntable 2. It is provided for.

  The film forming apparatus also includes an optical film thickness detection unit 14. The film thickness detection unit 14 irradiates light toward the film thickness detection wafer 9 installed on the upper surface of the central portion of the turntable 2 through the transmission window 13 formed on the top plate 11 to detect the film thickness. The film thickness of the film formed on the wafer 9 can be detected. As the film thickness detector 14, for example, an optical interference type film thickness meter that irradiates a light beam from a light source toward the wafer W and measures the film thickness based on the reflected light of the light beam can be used.

  Furthermore, the vacuum vessel 10 is placed on the top plate 11 at a film formation inhibition temperature (240 ° C.) that is higher than the heating temperature (200 ° C.) of the wafer W and inhibits film formation gas adsorption and suppresses polyimide formation. A container heating unit 71 is provided for heating the container. Thereby, formation of polyimide in the vacuum vessel 10 including the transmission window 13 is suppressed.

  In addition, the film forming apparatus includes an ultraviolet irradiation unit 8 for irradiating the rotary table 2 with ultraviolet rays and cleaning the rotary table 2. As shown in FIG. 3, when viewed from the upper surface side, the ultraviolet irradiation unit 8 is provided along the diametrical direction with the center C of the turntable 2 interposed therebetween. The ultraviolet irradiation unit 8 has a structure in which an ultraviolet lamp 83 is disposed inside the lamp house 82, and is configured to irradiate the surface of the rotary table 2 with ultraviolet rays through a transmission window 81 formed on the top plate 11. ing

The film forming apparatus having the above-described configuration includes a control unit 90 that is a computer, and the control unit 90 includes a program, a memory, and a CPU. In the program, instructions (each step: step group) are incorporated so as to advance processing on the wafer W described later. This program is stored in a computer storage medium such as a compact disk, a hard disk, a magneto-optical disk, a DVD, and the like, and is installed in the control unit 90. The control unit 90 outputs a control signal to each part of the film forming apparatus according to the program, and controls the operation of each part. Specifically, the exhaust flow rate by the vacuum pump 43, a flow rate adjustment unit M1, the flow rate of the gas supplied to M2 by processing vessel 11, the supply of _{N 2} gas from the _{N 2} gas supply source 52 and 62, to each of the heaters Each control object such as the supplied power is controlled by a control signal.

  In the film forming apparatus according to the embodiment having the configuration described above, the heating temperature of the wafer W and the supply amounts of the first film forming gas and the second film forming gas (the first film forming gas and the second film forming gas). The film thickness of the polyimide film formed on the surface of the wafer W is controlled using the partial pressure of the film forming gas as an operation variable.

  In an adsorption reaction in which monomers reacting with each other are adsorbed on the surface of the wafer W to form a film material, the amount of film material formed (hereinafter also referred to as “film formation amount”) is the amount of each monomer adsorbed on the wafer W. Depends on. The monomer adsorption amount on the wafer W depends on the collision frequency (collision amount per unit time) of each molecule of the first film forming gas and the second film forming gas which are monomers. Therefore, the adsorption amount of each monomer to the wafer W can be controlled by the partial pressure of the first film forming gas and the second film forming gas.

  On the other hand, when the monomer is viewed at the molecular level, if the vibration energy of the monomer adsorbed on the surface of the wafer W increases, the monomer desorbs from the surface of the wafer W. Therefore, the net adsorption amount of the monomer adhering to the surface of the wafer W is as shown in FIG. 5 in an amount that the monomer collides with the surface of the wafer W per unit time and the adsorbed monomer is the wafer W. It is determined by the balance with the amount desorbed from the surface. When the time during which the monomers of both film forming gases are adsorbed on the wafer W (adsorption residence time) becomes longer, the probability that the monomers adsorbed on the wafer W react with each other increases, and the amount of film formation increases.

  For this reason, for example, in the case of generating polyimide by the adsorption reaction between PMDA and ODA, if the temperature of the member is heated to 240 ° C. or higher, the amount of desorption becomes larger than the amount of monomer adsorbed per unit time, The net amount of monomer adsorbed on the surface is almost zero. Therefore, by heating the temperature of the gas supply nozzle 3 other than the wafer W to be deposited, the upstream pipe line, and the vacuum vessel 10 to, for example, 240 ° C. (corresponding to the aforementioned deposition inhibition temperature), Even if the first and second film-forming gases are mixed and supplied, the deposition of the film substance on the surfaces of these members can be suppressed.

  Summarizing the mechanism described above, when the supply amount (partial pressure) of each film formation gas is increased, the amount of adsorption of the monomer of the film formation gas increases and the film formation amount increases, and the supply amount (partial pressure) is reduced. When lowered, the amount of adsorption decreases and the amount of film formation decreases. Further, when the temperature of the wafer W is raised, the vibration energy of the monomer is increased, the amount of monomer desorption is increased, and the adsorption residence time is shortened, so that the film formation amount is decreased. On the contrary, when the temperature of the wafer W is lowered (however, it is heated to the reaction temperature or higher), the desorption amount of the monomer decreases and the adsorption residence time increases, so that the film formation amount tends to increase. .

  As discussed above, when film formation is performed by changing the supply amount of each film formation gas or the temperature of the wafer W, attention must be paid to the saturated vapor pressure of these film formation gases. If the pressure exceeds the saturation vapor pressure curve of the film-forming gas under a constant temperature condition, the film-forming gas may be liquefied and precise film thickness control cannot be performed. Therefore, in order to increase the amount of adsorption of the film forming gas, it is necessary to adjust the partial pressure of the film forming gas and the heating temperature of the wafer W within a range where the film forming gas is not liquefied.

  FIG. 6 is a characteristic diagram showing saturation vapor pressure curves of the first film-forming gas and the second film-forming gas, the horizontal axis indicates the temperature and the vertical axis indicates the logarithm. In the figure, the saturated vapor pressure curve of the first film-forming gas is indicated by a solid line, and the saturated vapor pressure curve of the second film-forming gas is indicated by a broken line. Note that the saturated vapor pressure curves of the first film forming gas and the second film forming gas shown in FIG. 6 are schematic representations, and do not describe the actual saturated vapor pressure curves of PMDA and ODA.

  As described with reference to FIG. 1, it is assumed that the first monomer and the second monomer react one-to-one to form a repeating unit structure of polyimide. For example, the saturated vapor pressure of the first film-forming gas is An example in which the saturation vapor pressure is lower than that of the second film forming gas will be described.

  In this case, first, with respect to a film forming gas having a low saturated vapor pressure (first film forming gas in the example shown in FIG. 6), the film forming gas is maintained at a temperature and a partial pressure under which the gas state can be maintained. A film forming process is performed. That is, in the example of FIG. 6, the film forming process may be performed under the temperature and partial pressure conditions below the saturation vapor pressure curve of the first film forming gas.

  For example, when the film forming process is performed at a predetermined heating temperature within the temperature range of the wafer W indicated by the one-dot chain line in FIG. 6, the partial pressure of the first film forming gas is increased as much as possible within the range below the saturated vapor pressure. Thus, the amount of the monomer colliding with the surface of the wafer W is increased. Thereby, the adsorption amount of the monomer can be increased.

  In addition, when the film forming process is performed at a predetermined film forming gas partial pressure in the partial pressure range indicated by a two-dot chain line in FIG. 6, the partial pressure of the first film forming gas is similarly in the range below the saturated vapor pressure. Lower the heating temperature as much as possible to reduce the amount of monomer desorption. As a result, the amount of monomer desorption can be reduced and the adsorption residence time can be increased.

On the other hand, the film forming gas having a high saturated vapor pressure (second film forming gas in the example shown in FIG. 5) has the same amount as the low vapor pressure gas (equal to partial pressure) in terms of stoichiometry. It can be considered that vapor pressure gas may be supplied. However, when the partial pressures are uniform, the high vapor pressure gas also reduces the amount of adsorption onto the wafer W compared to the low vapor pressure gas. Therefore, it is preferable to supply an excess amount of the high vapor pressure gas as compared with the low vapor pressure gas in a partial pressure range that does not exceed the saturated vapor pressure.
Note that the above-described method for setting the supply amount (partial pressure) of the film forming gas can be similarly applied to the case where the film forming gas is prevented from solidifying beyond the sublimation curve.

Based on the above concept, the supply amount of the low vapor pressure gas is set so that the partial vapor pressure does not exceed the saturation vapor pressure of the low vapor pressure gas having a low saturation vapor pressure. From the viewpoint of precisely controlling the film thickness, the first and second film forming gases have a low saturated vapor pressure (low vapor pressure gas), here the saturated vapor pressure of the first film forming gas. Is P0, and the partial pressure of the low vapor pressure gas supplied from the gas nozzle 3 is P1, the supply pressure of the first film forming gas is set so that P1 / P0 is 0.1 or less, respectively. Is preferred.
On the other hand, as described above, the deposition gas (high vapor pressure gas) having a high saturation vapor pressure among the first and second deposition gases has a partial pressure of P0 ′ and a partial pressure of the high vapor pressure gas. When P1 '
The value of P1 '/ P0' is 1 or less, and it is good to supply by partial pressure higher than low vapor pressure gas.

  Further, as described above, when the first and second film forming gases are supplied so as to flow in the lateral direction above the turntable 2, each film forming gas is consumed on the upstream side by adsorption to the wafer W. Therefore, the concentration of the film forming gas tends to decrease toward the downstream side. Therefore, if the amount of film forming gas adsorbed on the upstream side in the flow direction is too large, the film forming gas may be insufficient on the downstream side. In this case, the heating temperature of the wafer W is appropriately increased to adjust the monomer adsorption residence time, and a portion of the film forming gas once adsorbed in the upstream region of the flow is desorbed, Further, it may be adjusted so that the monomer is supplied.

Therefore, the heater 7 moves the wafer W to a temperature at which the reaction efficiency E, which is the ratio of the consumption of the film forming gas to each supplied film forming gas (first and second film forming gas), is 10% or less. Heat. Specifically, the supply flow rate of the low vapor pressure gas supplied from the gas supply nozzle 3 is L1, and the exhaust flow rate of the low vapor pressure gas reaching the exhaust duct 4 is L1 ′. The ratio of the deposition gas is defined as reaction efficiency E (%). At this time, the amount of the film forming gas consumed in the film forming process can be obtained from a difference value between the supply flow rate L1 of the low vapor pressure gas and the exhaust flow rate L1 ′ of the low vapor pressure gas. Based on this idea, by setting the heating temperature of the wafer W so that the reaction efficiency E represented by the following formula (1) is 10% or less, the film forming gas is insufficient on the downstream side in the flow direction of the film forming gas. The film-forming gas can be supplied over a region crossing the turntable 2 in the diametrical direction while suppressing the above.
E (%) = {(L1-L1 ′) / L1} × 100 (1)

Based on the concept described above, the operation of the film forming apparatus of this example for forming a polyimide film will be described. 4A to 4C show examples of sequences indicating timings of supplying the first film forming gas, the second film forming gas, and the purge gas in the film forming apparatus according to this example. Here, the time chart shown in FIG. 4A will be described as an example.
For example, six wafers W are mounted on the mounting units 24 of the turntable 2 by an external transfer mechanism (not shown), and the gate valve 16 is closed. The wafer W placed on the placement unit 24 is heated to a predetermined temperature, for example, 200 ° C. by the heater 7. Then it was evacuated through the exhaust port 51 by the vacuum evacuation unit 50, the _{N 2} gas supplied from _{N 2} gas supply source 52 and 62, the pressure in the vacuum chamber 10 (the total pressure), for example, 50 Pa (0. 4 Torr), and the rotary table 2 is rotated at, for example, 10 rpm to 30 rpm.

  Next, while maintaining the above total pressure, for example, a first film-forming gas containing PMDA and a second film-forming gas containing ODA are, for example, 1.33 Pa (0.01 Torr) and 1.46 Pa (0. The gas supply nozzle 3 is supplied with a partial pressure of 011 Torr). These film forming gases are merged and mixed in the introduction pipe on the upstream side of the gas supply nozzle 3, and are discharged from the gas supply nozzle 3 while being heated to 260 ° C., which is higher than the film formation inhibition temperature, for example. As shown in the time chart of FIG. 4A, PMDA and ODA are continuously supplied during the film forming process.

  As shown in FIG. 7, the first and second film forming gases discharged from the gas supply nozzle 3 are between the gas supply nozzle 3 and the outer edge of the moving region where the wafer W on the rotary table 2 revolves. It flows into the exhaust duct 4 side after colliding with the protruding wall portion 25 provided on the side. At this time, when the film forming apparatus is viewed from above, as shown in FIG. 8, the film forming gas collides with the protruding wall portion 25, so that the film forming gas is spread in the left-right direction as viewed from the gas supply nozzle 3. And then flows into the exhaust duct 4. As a result, the film forming gas discharged from the gas supply nozzle 3 linearly crosses the turntable 2 and prevents the formation of a flow that reaches the exhaust duct 4 as it is, and a wide range on the upper surface of the rotating turntable 2. Thus, the mixed gas can be efficiently supplied.

  By the above-described operation, each wafer W revolving around the center C of the turntable 2 repeatedly passes through the fan-shaped deposition gas flow region R shown in FIG. As a result, PMDA, which is a monomer contained in the first film-forming gas, and ODA, which is a monomer contained in the second film-forming gas, are adsorbed on the surface of each wafer W, and PMDA and A film is formed by reacting with ODA to become polyimide and depositing the polyimide.

  At this time, as described above, in the film forming apparatus according to the embodiment, P1 / P0 which is a ratio between the partial pressure P1 of the first and second film forming gases and the saturated vapor pressure P0 of the low vapor pressure gas. Is set to be 0.1 or less. As a result, liquefaction of low vapor pressure gas can be prevented and precise film thickness control can be performed.

  Further, the heating temperature of the wafer W is set so that the first and second film forming gases and the reaction efficiency E are 10% or less. Therefore, it is possible to once desorb a part of the film forming gas adsorbed on the wafer W and supply it again to the downstream side of the flow of the film forming gas. As a result, the film forming gas supplied from the gas supply nozzle 3 is not consumed on the turntable 2, and a sufficient amount of film forming gas reaches the exhaust duct 4, downstream of the flow region R shown in FIG. A sufficient film forming gas can be supplied to the side.

  Here, the concentration distribution of the film forming gas in the flow region R shown in FIG. 8 is gradually formed from the upstream side to the downstream side due to the consumption of the film forming gas when polyimide is formed on the wafer W. Gas concentration decreases. At this time, it can be seen that by appropriately adjusting the heating temperature of the wafer W, the change in the concentration of the deposition gas with respect to the distance from the deposition position of the deposition gas from the gas supply nozzle 3 can be approximated to a linear line. (Refer to preliminary experiments shown in FIGS. 13 and 14 described later). Therefore, in the film forming apparatus of this example, the heating temperature of the wafer W is set to 200 ° C., and the first and second film forming gases are reacted.

  FIG. 9 shows wafers W (symbols W1 and W2 for identifying each wafer W in FIG. 9) seen along the film-forming gas discharge direction (diameter direction of the turntable 2) at a certain point in time. ) Is schematically shown. When the concentration of the film forming gas shows a distribution that gradually decreases along the linear line according to the distance from the film forming gas discharge position, the amount of the film forming gas adsorbed also shows the same tendency. FIG. 9 schematically shows the film thickness distribution formed by the film forming gas adsorbed at this time (the film F portion painted in gray). According to FIG. 9, a thick film is formed by supplying a high concentration of film forming gas in a region close to the film forming gas discharge position, and a film forming gas concentration is decreased in a region close to the exhaust duct 4 side. The film thickness distribution can be approximated by a linear line on which a thin film is formed.

  Next, FIG. 10 schematically shows a longitudinal section of the wafer W when the turntable is rotated 180 degrees from the state of FIG. In FIG. 10, the film thickness distribution of the film F formed at the time of the 180 ° rotation is stacked on the upper surface side of the film thickness distribution formed in FIG. 9 (filled with a sand-like hatch). Membrane F part). As in the case of FIG. 9, a thick film is formed in a region close to the deposition gas discharge position, and a relatively thin film is formed in a region close to the exhaust duct 4 side. It becomes.

  Then, when the films formed at each time point in FIGS. 9 and 10 have a film thickness distribution that can be approximated by a linear line, if these films are laminated, the in-plane of each wafer W and a plurality of films are stacked. A film having a substantially uniform thickness between the surfaces of the wafer W is formed.

  Actually, at each point in the surface of the wafer W, during the period of passing through the deposition gas flow region R schematically shown in FIG. And proceed. Then, by depositing the polyimide, a film F having a thickness corresponding to the time of passing through the flow region R and the concentration of the deposition gas at each position is formed. During this period, deposition of a film having a film thickness distribution described in a model manner with reference to FIGS. 9 and 10 is repeated and continuously performed, for example, in a state where the rotation of the turntable 2 is stopped. Compared to the case where the treatment is performed, the film F having a flat film thickness distribution can be formed.

  In addition, the film forming apparatus of this example includes a film thickness detecting unit 14 and can detect the film thickness of the film thickness detecting wafer 9 provided at the center of the upper surface of the turntable 2. The operation of forming the film F having a uniform thickness in the plane and between the planes described with reference to FIGS. 9 and 10 is the same as in the film thickness detection wafer 9. Therefore, the film thickness formed on the wafer W placed on the placement unit 24 is equal to the film thickness formed on the film thickness detection wafer 9 placed at the rotation center of the turntable 2. For this reason, the film thickness of the film formed on the wafer W can be specified with high accuracy by detecting the film thickness of the film formed on the film thickness detecting wafer 9. Since the film thickness at the center of the turntable 2 is also the same, the optical film thickness detection unit 14 detects the film thickness above the center of the turntable 2 where the position does not move when the turntable 2 rotates. Thus, the film thickness of the film formed on the wafer W can be continuously monitored.

At this time, the vacuum container 10 is heated to a film formation inhibition temperature higher than the heating temperature of the wafer W by the container heating unit 71. For this reason, in addition to the inner surface of the vacuum vessel 10, it is possible to suppress the deposition of the film substance on the transmission window 13 that transmits the light irradiated from the film thickness detection unit 14.
The film thickness detection unit is not limited to the case where an optical type is used. For example, a weighing scale that measures the weight of the film formed on the film thickness detecting wafer 9 may be used as the film thickness detecting unit. Further, a crystal resonator may be provided in place of the film detection wafer 9, and the film thickness may be detected by changing the frequency of the crystal resonator due to the film being formed on the surface.

When a film having a preset film thickness is formed based on the operation described above, the supply of the film forming gas, the rotation of the turntable 2 and the heating of the wafer W are stopped, and the procedure opposite to that at the time of loading is performed. After unloading the wafer W after the film formation process, the process waits for the start of the next film formation process.
At this time, before starting the next film forming process, for example, O ₂ gas is supplied into the vacuum vessel 10 and ultraviolet rays are irradiated by the ultraviolet lamp 83. Thus, the activated O ₂ gas may be supplied to the surface of the turntable 2, and a process of decomposing the polyimide film formed in the region not covered by the wafer W other than the mounting unit 24 may be performed. Further, the film formed on the turntable 2 may be decomposed after performing a predetermined number of film forming processes.

  According to the above-described embodiment, the gas supply nozzle 3 for supplying the first film forming gas and the second film forming gas is set in the radial direction from the outer side of the turntable 2 on which the plurality of wafers W are placed. In addition, the exhaust duct 4 is provided at a position opposite to the direction in which the film forming gas is discharged from the gas supply nozzle 3 with the rotary table interposed therebetween. With this configuration, since a film forming process can be performed on a plurality of wafers W at the same time, productivity is improved. In addition, the in-plane thickness of the film formed on the wafer W by revolving the wafer W while supplying the first film-forming gas and the second film-forming gas in the radial direction from the outer side of the turntable 2. Uniformity and uniformity between surfaces are improved.

  In the example described with reference to FIGS. 2 and 3, the collision target member 25 for spreading the film forming gas is provided on the peripheral edge of the turntable 2. However, other configurations may be employed. For example, as shown in FIG. 11, it protrudes downward from the ceiling surface of the vacuum vessel 10 between the gas supply nozzle 3 and the moving area where the wafer W moves when the turntable 2 rotates. The member 26 to be collided may be provided.

  Furthermore, as shown in FIG. 12A, a film formed using the film forming apparatus according to the embodiment reacts with a film forming gas containing a monomer having an amino group and a film forming gas containing a monomer having an epoxy group. It may be formed of a film substance having an epoxy bond. Further, as shown in FIG. 12B, a film may be formed from a film substance having a urea bond by using a film forming gas containing a monomer having an amino group and a film forming gas containing a monomer having an isocyanate. Alternatively, as shown in FIG. 12C, a film may be formed from a film material having an imide bond with a film forming gas containing a monomer having an amino group and a film forming gas containing a monomer that is an acid anhydride. Furthermore, a film substance having a urethane bond with a film forming gas containing a monomer that is alcohol and a film forming gas containing a monomer that is isocyanate, a film forming gas containing a monomer having an amino group, and a monomer that is a carboxylic acid A film may be formed from a film substance having an amide bond with a film-forming gas containing. Further, a film may be formed by forming a polymer by copolymerization, two-molecule reaction, three-molecule reaction, or a mixture of three kinds.

  The first film forming gas and the second film forming gas are formed by combining monomers having functional groups such as isocyanate groups and amino groups which are monofunctional with each other and monomers having two or more functional groups with each other. May be formed. Furthermore, as a skeleton structure of a monomer for forming a film substance, aromatic, alicyclic, aliphatic, and aromatic and aliphatic conjugates can be used.

  In the film forming apparatus of the embodiment, in addition to the continuous supply of each film forming gas shown in FIG. 4A, for example, as shown in FIG. 4B, a first film forming gas (PMDA in the figure) and a second The film forming gas (ODA in the figure) may be alternately supplied. Alternatively, as shown in FIG. 4C, the purge gas may be supplied every time one cycle of supplying the first film forming gas and supplying the second film forming gas is performed. Furthermore, the gas supply unit that supplies the first film-forming gas and the gas supply unit that supplies the second film-forming gas may be provided independently of each other.

In addition, the deposited film may be modified by irradiating the wafer W placed on the turntable 2 with ultraviolet rays by the ultraviolet irradiation unit 8 described above. Alternatively, instead of the ultraviolet irradiation unit 8, an infrared irradiation unit that irradiates infrared rays on the surface of the turntable 2 may be provided, and the film substance attached to the turntable 2 may be removed by heat. Further, both an irradiation unit for cleaning and an irradiation unit for modifying the wafer W may be provided.
Further, the exhaust port 41 is not limited to a configuration provided so as to expand in a direction intersecting with the direction in which the film forming gas is supplied from the gas supply nozzle 3 when viewed from the upper surface side. For example, one exhaust port 41 may be provided on the side wall surface of the container body 12 that is provided in the gas supply nozzle 3 and faces the above-described gas discharge port that discharges the film forming gas. In addition, the gas discharge port on the gas supply nozzle 3 side may be provided so as to extend in a direction intersecting with the direction in which the film forming gas is supplied.
As discussed above, the embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The above-described embodiments may be omitted, replaced, and modified in various forms without departing from the scope and spirit of the appended claims.

  Next, the result of a preliminary experiment for confirming that the concentration distribution of the film forming gas described with reference to FIGS. 9 and 10 is formed will be described. As shown in FIG. 13, a single-wafer type film forming apparatus provided with a mounting table 101 on which a wafer W is mounted in a vacuum vessel 100 and having a heater 102 embedded in the mounting table 101 was used for a preliminary experiment. Similarly to the film forming apparatus shown in FIGS. 1 and 2, a gas supply nozzle 3 for supplying a first film forming gas (PMDA) and a second film forming gas (ODA) is provided on the side wall of the vacuum vessel 100. The film forming gas can be supplied in the lateral direction toward the surface of the wafer W mounted on the mounting table 101. On the other hand, an exhaust port 4a constituting an exhaust unit is provided at a position opposite to the direction in which the film forming gas is discharged from the gas supply nozzle 3 with the mounting table 101 interposed therebetween.

Using such a film forming apparatus, the temperature of the wafer W is set to 140, 160, 180, and 200 ° C., respectively, and the film forming process is performed. The film extends in the film forming gas discharge direction and runs along the straight line passing through the center of the wafer W. The film thickness distribution at different positions was examined. The pressure in the vacuum vessel 100 and the partial pressures of the first and second film forming gases are set in the same manner as the film forming apparatus according to the embodiment described with reference to FIGS. The sequence of FIG. 4A was used for the deposition gas supply sequence.
FIG. 14 is a characteristic diagram showing the film thickness distribution when the heating temperature of the wafer W is set to 140, 160, 180 and 200 ° C., respectively. The horizontal axis in FIG. 14 indicates the distance from the film formation gas discharge position, and the vertical axis indicates the film thickness of the polyimide film formed at each position.

  As shown in FIG. 14, at any heating temperature, it can be seen that the film thickness of the film formed on the wafer W decreases as the distance from the gas supply nozzle 3 increases. For example, when the heating temperature of the wafer W is the lowest, 140 ° C., a film formed on the wafer W is thicker than other heating temperatures in a region near the discharge position from the gas supply nozzle 3. As the distance from the discharge position increases, the distance decreases rapidly so as to draw a curve. This is because, as described with reference to FIG. 5, when the heating temperature is relatively low, the amount of the monomer adsorbed on the wafer W is reduced, so that the film in the region near the discharge position is thickened. It is considered that the amount of monomer in the film-forming gas flowing downstream decreases rapidly, and the film becomes thinner accordingly.

  On the other hand, when the heating temperature of the wafer W is increased to 200 ° C., for example, the film thickness decreases so as to draw a linear line with respect to the distance from the discharge position. This is presumably because the amount of monomer released from the wafer W increases as the heating temperature increases, and the film in the region near the discharge position becomes thinner. A part of the desorbed monomer is re-adsorbed to the wafer W on the downstream side of the flow of the film forming gas, but since the desorption amount of the monomer is increased also in the downstream region, the heating temperature is set to 140 ° C. It is considered that the film thickness is about the same as that when set to.

  Thus, by changing the heating temperature of the wafer W, the film thickness distribution of the film formed on the wafer W can be changed. When PMDA and ODA are used as the first film forming gas and the second film forming gas, the heating temperature of the wafer W is set to about 200 ° C., so that the distance from the film forming gas supply position is set. It was confirmed that it is possible to form a film thickness distribution in which the film thickness decreases with a linear line. Therefore, by forming a similar film thickness distribution on the turntable 2 and revolving the wafer W placed on the turntable 2, as described with reference to FIGS. It can be said that a film having a more uniform film thickness distribution between the surfaces can be formed.

3 Gas supply nozzle 4 Exhaust duct 2 Rotary table 10 Vacuum vessel 7 Heater

Claims (15)

A processing vessel in which a vacuum atmosphere is formed;
A rotary table provided in the processing container, wherein a substrate placement area for placing a plurality of substrates is formed on one side thereof, and provided with a rotation mechanism for revolving the substrate placement area around a rotation axis. When,
A heating mechanism for heating the substrate placed in the substrate placement region;
A first film-forming gas and a second film-forming gas which are provided in the processing container and are adsorbed on the surface of the substrate heated by the heating mechanism and react with each other to form a film material. A gas supply unit that supplies the gas toward the radial direction of the rotary table;
A film forming apparatus comprising: an exhaust unit provided at a position opposite to a direction in which the film forming gas is discharged from the gas supply unit with the rotary table interposed therebetween.   The gas supply unit is provided between the gas supply unit and an outer edge of a moving region where the substrate moves when the rotary table is rotated. The film forming apparatus according to claim 1, further comprising a colliding member for spreading a film forming gas on the upper surface.   The film forming apparatus according to claim 2, wherein the collision target member is provided along a circumferential direction of the turntable so as to protrude upward from an upper surface of the turntable.   The film forming apparatus according to claim 2, wherein the collision target member is provided so as to protrude downward from a ceiling surface of the processing container. The saturation vapor pressure of the low vapor pressure gas having a low saturation vapor pressure among the first film formation gas and the second film formation gas is P0, and the first and second film formation supplied from the gas supply unit. When the gas partial pressure P1 is set, the supply pressures of the first and second film forming gases are set so that P1 / P0 is 0.1 or less,
5. The heating mechanism according to claim 1, wherein the heating mechanism heats the substrate to a temperature at which a reaction efficiency, which is a ratio of consumption of the film forming gas to each supplied film forming gas, is 10% or less. The film forming apparatus according to claim 1.   The said exhaust part is provided with the exhaust port provided so that it might spread in the direction which cross | intersects the direction where film-forming gas is supplied from the said gas supply part seeing from the upper surface side. The film-forming apparatus as described in any one.   The film forming apparatus according to claim 1, further comprising a film thickness detection unit that detects a film thickness of a film formed on a central portion of the upper surface of the turntable.   The film thickness detector is an optical film thickness meter that optically detects the film thickness, and is used for measuring the film thickness at the central portion through a light transmission window provided on the ceiling surface side of the processing container. The film forming apparatus according to claim 7, wherein the film thickness is detected based on a result of irradiating the light.   Provided with a container heating unit that heats the processing container to a film formation inhibition temperature that is higher than the temperature of the substrate heated by the heating mechanism and inhibits film formation gas adsorption and suppresses film formation. The film forming apparatus according to claim 1, wherein the film forming apparatus is provided.   The irradiation part which irradiates the light for performing the process of a film | membrane toward the said rotary table side was provided in the ceiling surface side of the said process container, The Claim 1 thru | or 8 characterized by the above-mentioned. The film-forming apparatus of description.   The irradiation unit is an ultraviolet irradiation unit for activating the cleaning gas supplied through the gas supply unit and cleaning the film attached to the surface of the rotary table. The film-forming apparatus of description.   The film forming apparatus according to claim 10, wherein the irradiation unit is an ultraviolet irradiation unit for modifying the film. A step of placing a substrate on a plurality of substrate placement regions formed in one surface side of a turntable provided in a processing container in which a vacuum atmosphere is formed, and revolving the substrate around a rotation axis of the turntable;
Next, the substrate placed on the substrate placement region is heated, and the first film forming gas that is adsorbed on the surface of the heated substrate and reacts with each other to form a film substance is formed. Supplying a gas and a second film-forming gas in a radial direction of the rotary table;
In parallel with the step of supplying the film forming gas, the film forming gas in the processing container is exhausted at a position opposite to the direction in which the film forming gas is discharged from the gas supply unit with the rotary table interposed therebetween. A film forming method comprising the steps of:   In the step of supplying the film forming gas, the film forming gas is provided between a position where the first and second film forming gases are supplied and an outer edge of a moving region where the substrate moves when the rotary table is rotated. The film forming method according to claim 13, wherein the film forming gas is caused to collide with a collision target member to spread the film forming gas on the upper surface of the rotary table. In the step of supplying the film forming gas, the saturated vapor pressure of the low vapor pressure gas having a low saturated vapor pressure among the first film forming gas and the second film forming gas is set to P0 and supplied from the gas supply unit. Assuming that the partial pressure P1 of the first and second film-forming gases is set, the supply pressures of the first and second film-forming gases are set so that P1 / P0 is 0.1 or less, respectively. ,
The substrate is heated to a temperature at which a reaction efficiency, which is a ratio of consumption of the film forming gas to each film forming gas supplied to the processing container, becomes 10% or less. The film-forming method of description.

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