TWI415177B - A substrate processing method and a substrate processing apparatus - Google Patents

Abstract

To provide a substrate processing method capable of easily removing a remaining product due to a hydrofluoric acid. An HF gas is supplied to a wafer W having a thermal oxidation film 61 and a BPSG film 63 to selectively etch the BPSG film 63. Subsequently, an NH3 gas is supplied to the wafer W, and allows an H2 SiF6 gas to react to an NH3 gas of the remaining product 64 generated on the basis of the reaction between the SiO2 and the hydrofluoric acid to generate NH4 F and SiF4. Further, the NH4 F is allowed to sublimate.

Description

Substrate processing method and substrate processing device

The present invention relates to a substrate processing method and a substrate processing apparatus, and more particularly to a substrate processing method for processing a substrate on which a thermal oxide film and an oxide film containing impurities are formed.

A wafer (substrate) for a semiconductor device including a thermal oxide film formed by thermal oxidation treatment and an oxide film containing impurities formed by CVD treatment or the like, and a BPSG (Boron Phosphorous Silicate Glass) film is known. The BPSG film is formed by partially exposing a part of the polysilicon film on the polysilicon film, and functions as a hard mask when the polysilicon film is etched. The thermal oxide film constitutes a gate oxide film.

Such a substrate does not remove (etch) the thermal oxide film after the polysilicon film is etched, but is required to selectively remove the BPSG film.

When the oxide film is etched, a CF-based gas plasma is usually used. However, since the CF-based gas plasma etches only the BPSG film and etches the thermal oxide film, it is difficult to ensure the selection ratio of the BPSG film to the thermal oxide film, and the BPSG film cannot be selectively etched.

In response to this, an etching method in which HF gas or a mixed gas of HF gas and H ₂ O gas is not used is proposed (see Patent Document 1). In this method, the fluorine-containing acid produced by the combination of HF gas and H ₂ O can preferentially remove the oxide film containing impurities, and as a result, the BPSG film can be selectively etched.

Patent Document 1: Japanese Patent Publication No. 06-181188

However, when the BPSG film is etched using HF gas or a mixed gas of HF gas and H ₂ O gas, a reaction occurs between the SiO ₂ and the hydrofluoric acid, and the residue adheres to the surface of the wafer for a semiconductor device. This residue causes problems such as short-circuiting of the semiconductor package manufactured from the wafer.

An object of the present invention is to provide a substrate processing method and a substrate processing apparatus which can easily remove residues caused by hydrofluoric acid.

In order to achieve the above object, a substrate processing method according to the first aspect of the invention is directed to a substrate having a first oxide film formed by thermal oxidation treatment and a second oxide film containing impurities; The HF gas supply step is characterized in that the HF gas is supplied to the substrate, and the cleaning gas supply step is for supplying a cleaning gas containing at least NH ₃ gas to the substrate to which the HF gas is supplied.

The substrate processing method according to the second aspect of the invention is the substrate processing method of claim 1, wherein the H ₂ O gas is not supplied in the HF gas supply step.

The substrate processing method according to the third aspect of the invention, wherein the substrate has a film formed on the first oxide film and covered by the second oxide film. In the ruthenium layer, one of the second oxide films partially exposes the ruthenium-containing layer, and the ruthenium-containing layer is etched before the HF gas supply step.

In order to achieve the above object, a substrate processing method according to the fourth aspect of the invention is directed to a substrate having a first oxide film formed by thermal oxidation treatment and a second oxide film containing impurities; The method includes an HF gas supply step for supplying HF gas to the substrate, and a substrate heating step for heating the substrate to which the HF gas is supplied.

The substrate processing method of claim 5, wherein in the substrate processing method of the fourth aspect of the invention, the substrate is heated in the N ₂ gas atmosphere.

The substrate processing method of claim 6 is the substrate processing method of claim 4 or 5, wherein the substrate is heated to 150 ° C or higher in the substrate heating step.

In order to achieve the above object, a substrate processing apparatus according to a seventh aspect of the invention is directed to a substrate having a first oxide film formed by thermal oxidation treatment and a second oxide film containing impurities; The HF gas supply device is configured to supply HF gas to the substrate, and the cleaning gas supply device is configured to supply a cleaning gas containing at least NH ₃ gas to the substrate to which the HF gas is supplied.

In order to achieve the above object, a substrate processing apparatus according to claim 8 is directed to a substrate having a first oxide film formed by thermal oxidation treatment and a second oxide film containing impurities; The method includes an HF gas supply device for supplying HF gas to the substrate, and a substrate heating device for heating the substrate to which the HF gas is supplied.

Embodiments of the present invention will be described with reference to the drawings.

First, a substrate processing system including a substrate processing apparatus according to a first embodiment of the present invention will be described.

Fig. 1 is a plan view showing a schematic configuration of a substrate processing system including a substrate processing apparatus according to the embodiment.

In FIG. 1, the substrate processing system 10 includes a first processing unit 11 for performing plasma processing on a semiconductor device wafer (hereinafter simply referred to as "wafer") W (substrate), and a second processing portion 12 (substrate) The processing device is disposed in parallel with the first processing unit 11 and performs a specific processing to be described later for the wafer W subjected to the plasma processing of the first processing unit 11 and a loader as a rectangular common transfer chamber. The module 13 is connected to the first process unit 11 and the second process unit 12, respectively.

In the loading module 13, in addition to the first processing unit 11 and the second processing unit 12, three FOUP (Front Opening Unified Pod) mounting tables 15 are separately connected and placed therein. a FOUP (Front Opening Unified Pod) 14 as a container of 25 wafers W; a positioner 16 for pre-positioning the position of the wafer W carried out by the FOUP 14; 2IMS (Integrated Metrology System, Therma-Wave, Inc.) 17, 18 is used to measure the surface state of the wafer W.

The first processing unit 11 and the second processing unit 12 are connected to the side wall along the longitudinal direction of the loading module 13 and hold the loading module 13 and are disposed opposite to the three FOUP mounting tables 15 . The positioner 16 is disposed at one end of the longitudinal direction of the loading module 13, and the first IMS 17 is disposed at the other end of the longitudinal direction of the loading module 13, the second IMS 18 system and the three FOUP mounting tables 15 Parallel configuration.

The loading module 13 has a scalar type double-arm type transfer arm mechanism 19 that is disposed inside and transports the wafer W, and a wafer W disposed on the side wall corresponding to each FOUP mounting table 15 Three load ports 20 of the input port. The transfer arm mechanism 19 picks up the wafer W from the loading port 20 by the FOUP 14 placed on the FOUP mounting table 15 , and the taken wafer W is applied to the first processing unit 11 , the second processing unit 12 , and the positioner 16 . The first IMS 17 or the second IMS 18 carries in and out.

The first IMS 17 is an optical monitor, and has a mounting table 21 for placing the loaded wafer W, and an optical sensor 22 for orienting the wafer W placed on the mounting table 21; The surface shape of W, for example, the film thickness of the polysilicon film and the CD (Critical Dimension) value of the wiring trench or the gate. The second IMS 18 is also an optical system monitor, and has a mounting table 23 and an optical sensor 24 similarly to the first IMS 17.

The first processing unit 11 includes a first process module 25 for plasma processing the wafer W, and a first vacuum isolation module 27 having a first type of a single type of connection type (Single Pick). The transfer arm unit 26 is used to perform the receipt and payment of the wafer W to the first process module 25.

The first process module 25 has a cylindrical processing chamber container (chamber), and an upper electrode and a lower electrode (none of which are shown) disposed in the chamber, and the distance between the upper electrode and the lower electrode is set to The wafer W is subjected to an appropriate interval of etching treatment as a plasma treatment. Further, the lower electrode has the ESC 28 at the top thereof to hold the wafer W by Coulomb force or the like.

In the first process module 25, a processing gas containing a CF-based gas is introduced into the chamber, and an electric field is generated between the upper electrode and the lower electrode to plasmaize the introduced processing gas to generate ions and radicals. The wafer W is etched by ions and radicals.

In the first processing unit 11, the internal pressure of the loading module 13 is maintained at atmospheric pressure, and the internal pressure of the first process module 25 is maintained at a vacuum. Therefore, the first load lock unit 27 is provided with the vacuum gate valve 29 at the connection portion with the first process module 25, and is provided with the atmospheric gate valve 30 at the connection portion with the load module 13 According to this, it is configured as a vacuum preparation transfer chamber in which the internal pressure can be adjusted.

In the first vacuum isolation module 27, the first transfer arm unit 26 is provided at a substantially central portion, and the first buffer unit 31 is provided closer to the first process module 25 than the first transfer arm unit 26, which is the first The transfer arm unit 26 is provided with the second buffer unit 32 closer to the loading module 13 side. The first buffer portion 31 and the second buffer portion 32 are disposed on a rail on which the support portion (pick) 33 moves, and the support portion 33 supports the wafer W disposed at the front end portion of the first transfer arm portion 26 to be electrically operated. The wafer W after the slurry treatment is temporarily prevented from being above the track of the support portion 33. Thus, the smooth replacement of the wafer W that has not been subjected to the etching process and the wafer W that has been subjected to the etching process to the first process module 25 is possible. .

The second processing unit 12 includes a second process module 34 for performing a specific process to be described later on the wafer W, and a second vacuum isolation module 37 having a second transfer arm unit of a connected single chuck type. 36. The vacuum gate valve 35 is connected to the second process module 34, and the wafer W can be received/paid by the second process module 34.

2 is a cross-sectional view of the second process module of FIG. 1, FIG. 2(A) is a cross-sectional view taken along line I-I of FIG. 1, and FIG. 2(B) is a portion of FIG. 2(A) Expand the map.

In FIG. 2(A), the second process module 34 includes a cylindrical processing chamber container (chamber) 38, a mounting table 39 of the wafer W disposed in the chamber 38, and a chamber 38 disposed therein. a jet head 40 that faces the mounting table 39, a TMP (Turbo Molecular Pump) 41 that exhausts gas or the like in the chamber 38, and a chamber 38 and TMP 41 that are disposed in the control chamber 38. The pressure is used as an APC (Adaptive Pressure Control) valve 42 of a variable butterfly valve.

The air jet head 40 is composed of a disk-shaped lower layer gas supply unit 43 (clean gas supply device) and a disk-shaped upper layer gas supply unit 44 (HF gas supply device), and the lower layer gas supply unit 43 overlaps the upper layer gas supply unit 44. . The lower gas supply unit 43 and the upper gas supply unit 44 have a first buffer chamber 45 and a second buffer chamber 46, respectively. The first buffer chamber 45 and the second buffer chamber 46 communicate with each other through the gas vent holes 47 and 48 in the chamber 38.

The first buffer chamber 45 of the lower gas supply unit 43 of the air jet head 40 is connected to an NH ₃ (ammonia) gas supply system (not shown), and the NH ₃ (ammonia) gas supply system supplies NH to the first buffer chamber 45. ₃ gas (cleaning gas). The supplied NH ₃ gas is supplied into the chamber 38 through the gas vent 47.

The second buffer chamber 46 of the upper gas supply unit 44 of the air jet head 40 is connected to an HF gas supply system that supplies HF gas to the second buffer chamber 46. The supplied HF gas is supplied into the chamber 38 through the gas vent 48. The upper gas supply unit 44 of the air jet head 40 contains a heater (not shown), for example, a heating element that controls the temperature of the HF gas in the second buffer chamber 46.

Further, as shown in Fig. 2(B), in the air jet head 40, the opening portion in the chamber 38 in the gas vent holes 47, 48 is formed in a terminally enlarged shape. Accordingly, the NH ₃ gas or the HF gas can be efficiently diffused into the chamber 38. Further, the cross-sections of the vent holes 47 and 48 have a bee-waist shape, and it is possible to prevent the sediment generated in the chamber 38 from flowing back to the vent holes 47 and 48, that is, toward the first buffer chamber 45 or the second buffer chamber 46.

Further, in the second process module 34, a heater (not shown), for example, a heating element, is housed in the side wall of the chamber 38, and the ambient temperature in the chamber 38 can be set to be higher than normal temperature, thereby facilitating the borrowing described later. The BPSG film 63 is removed by hydrofluoric acid. Further, the heating element in the side wall prevents the residue generated when the BPSG film 63 is removed by the hydrofluoric acid from adhering to the inside of the side wall by heating the side wall.

The mounting table 39 has a refrigerant chamber (not shown) as a temperature adjustment mechanism. A refrigerant of a specific temperature, such as cooling water or perfluoropolyether oil (Galden), is supplied to the refrigerant chamber, and the temperature of the wafer W placed on the mounting table 39 is controlled by the temperature of the refrigerant.

Returning to Fig. 1, the second vacuum isolation module 37 has a housing-like transfer chamber (chamber) 49. The internal pressure of the loading module 13 is maintained at atmospheric pressure, and the internal pressure of the second process module 34 is maintained below atmospheric pressure, such as vacuum. Therefore, the second vacuum insulation module 37 is provided with a vacuum gate valve 35 at the connection portion with the second process module 34, and an atmospheric gate valve 55 is provided at the connection portion between the second vacuum module 37 and the loading module 13, and is configured accordingly. The vacuum preparation chamber is a vacuum that can adjust its internal pressure.

Further, the substrate processing system 10 includes an operation panel 56 disposed at one end of the longitudinal direction of the loading module 13. The operation panel 56 has a display unit configured by, for example, an LCD (Liquid Crystal Display), and the display unit displays the operation state of each component of the substrate processing system 10.

However, on the tantalum substrate 60 shown in Fig. 3(A), a thermal oxide film 61 (first oxide film) composed of SiO ₂ formed by thermal oxidation treatment, a polycrystalline tantalum film 6 (containing a tantalum layer), and borrowed When the BPSG film 63 (the second oxide film) formed by the CVD process or the like is laminated, when the BPSG film 63 is selectively etched, as described above, the HF gas or the HF gas and the H ₂ O gas are not allowed. The mixed gas is plasmated. Further, the BPSG film 63 is partially exposed to the thermal oxide film 61 after etching of the polysilicon film 62.

As a result of various experiments for increasing the selection ratio of the BPSG film 63 to the thermal oxide film 61, the inventors have found that when the H ₂ O gas is not supplied and the HF gas is supplied only to the wafer W in the case where there is almost no H ₂ O atmosphere. As shown in the distribution diagram of FIG. 4, the etching rate of the thermal oxide film 61 is maintained at 5 nm/min, and the etching rate of the BPSG film 63 can be increased to 500 nm/min. That is, it has been found that the selection ratio of the BPSG film 63 to the thermal oxide film 61 can be increased to 1000. In addition, the inventors found that the etching rate of the TEOS film under the above conditions can be increased to 20 nm/min.

The present inventors have inferred the following hypothetical explanations for the mechanism of the above-described high selection ratio.

The HF gas combines with H ₂ O to form a hydrofluoric acid, and the hydrofluoric acid invades to remove the oxide film. In the case where there is almost no H ₂ O, when HF gas is to be hydrofluoric acid, it needs to be combined with water (H ₂ O) molecules contained in the oxide film.

The BPSG film 63 is formed by vapor deposition such as CVD treatment, and the structure of the film is a sparse structure, and it is easy to adsorb water molecules. Therefore, the BPSG film 63 contains a certain degree of water molecules. The HF gas reaching the BPSG film 63 is combined with the water molecules to become hydrofluoric acid, and the hydrofluoric acid intrudes into the BPSG film 63.

Further, the thermal oxide film 61 is formed by thermal oxidation treatment in an environment of 800 ° C to 900 ° C, and the film is formed without water molecules, and the structure of the film is a dense structure, and it is not easy to adsorb water molecules. Therefore, the thermal oxide film 61 hardly contains water molecules, and since the supplied HF gas reaches the thermal oxide film 61 without being hydrolyzed, it does not become hydrofluoric acid, and as a result, the thermal oxide film 61 is not invaded.

In this manner, when the H ₂ O gas is not supplied and the HF gas is supplied to the wafer W in the absence of the H ₂ O atmosphere, the selection ratio of the BPSG film 63 to the thermal oxide film 61 can be increased to 1,000.

However, when the BPSG film 63 is removed by the hydrofluoric acid, the SiO ₂ and the hydrofluoric acid (HF) in the BPSG film 63 cause a chemical reaction represented by the following formula: SiO ₂ + 4HF → SiF ₄ + 2H ₂ O ↑ SiF ₄ + 2HF → H ₂ SiF ₆

A residue (H ₂ SiF ₆ ) is produced.

In contrast, in the present embodiment, NH ₃ is used to remove the residue. Specifically, the chemical reaction shown by the following formula is caused by supplying NH ₃ gas to H ₂ SiF ₆ ): H ₂ SiF ₆ +2NH ₃ → 2NH ₄ F+SiF ₄ ↑

NH ₄ F (fluorinated ammonia) and SiF ₄ (fluorene tetrafluoride) are produced. NH ₄ F (fluorine fluoride) is a substance that is easy to sublimate, and can be removed as long as the ambient temperature is set to be slightly higher than normal temperature.

That is, in the present embodiment, the reaction residue (H ₂ SiF ₆ ) of SiO ₂ and hydrofluoric acid is removed by reaction and sublimation with NH ₃ .

The substrate processing method of this embodiment will be described below.

FIG. 5 is a flow chart of a substrate processing method performed by the substrate processing system of FIG. 1. FIG.

First, a wafer W in which the polycrystalline germanium film 62 is uniformly formed on the thermal oxide film 61 and the BPSG film 63 is formed on the polycrystalline germanium film 62 to partially expose the polycrystalline germanium film 62 is prepared. The wafer W is carried into the chamber of the first process module 25 and placed on the ESC 28.

Thereafter, a processing gas containing a CF-based gas is introduced into the chamber, an electric field is generated between the upper electrode and the lower electrode, and the processing gas is plasma-formed to generate ions and radicals, and the polycrystalline germanium film 62 is exposed by the ions and radicals. Etching process (step S51). At this time, the polysilicon film 62 is etched to form a via hole or a trench. Further, a part of the thermal oxide film 61 is exposed (Fig. 3(A)).

Thereafter, the wafer W is carried out from the chamber of the first process module 25, and is carried into the chamber 38 of the second process module 34 via the loading module 13. At this time, the wafer W is placed on the mounting table 39.

Thereafter, the pressure in the chamber 38 is set to 1.3 × 10 ¹ to 1.1 × 10 ³ Pa (1 to 8 Torr) by the APC valve 42, and the temperature in the chamber 38 is set to 40 to 60 ° C by the heater in the side wall. . Thereafter, the upper layer gas supply unit 44 of the air jet head 40 supplies HF gas to the wafer W at a flow rate of 40 to 60 SCCM (HF gas supply step) (step S52) (Fig. 3(B)). Further, at this time, most of the water molecules are removed from the chamber 38, and no H ₂ O gas is supplied to the chamber 38.

Here, the HF gas reaching the BPSG film 63 and the water molecules contained in the BPSG film 63 are combined to form hydrofluoric acid, and the hydrofluoric acid intrudes into the BPSG film 63. As a result, the BPSG film 63 is selectively etched, but the SiO ₂ in the BPSG film 63 is The hydrofluoric acid (HF) reacts to produce a residue 64 which is deposited on the polysilicon film 62 or the exposed thermal oxide film 61.

After that, after the HF gas is supplied to the chamber 38, the NH ₃ gas is supplied from the lower gas supply unit 43 to the wafer W (the cleaning gas supply step) (step S53) (Fig. 3(D) At this time, the NH ₃ gas reacts with H ₂ SiF ₆ constituting the residue 64 to generate NH ₄ F (fluorinated ammonia) and SiF ₄ (fluorene tetrafluoride). As long as the ambient temperature in the chamber 38 is set slightly higher than NH ₄ F can be sublimated at room temperature (Fig. 3(E).

Thereafter, the wafer W is carried out from the chamber 38 of the second process module 34, and the process is terminated.

Based on the processing of FIG. 5, HF gas is supplied to the wafer W having a thermal oxide film 61 and the BPSG film 63, and then NH ₃ gas is supplied to the wafer W. The HF gas generated by the hydrofluoric acid so that the BPSG film 63 is selectively etched, but is generated composed of the H ₂ SiF ₆ residue 64, NH ₃ gas and H ₂ SiF ₆ to produce NH ₄ F reaction with SiF _4. NH ₄ F is easy to sublimate. Therefore, the residue 64 can be removed by reaction with the NH ₃ gas and sublimation. In this way, the residue 64 composed of H ₂ SiF ₆ can be easily removed.

In the process of FIG. 5, when HF gas is supplied to the wafer W, almost all water molecules in the chamber 38 are removed, and no H ₂ O gas is supplied to the chamber 38. Therefore, in the thermal oxide film 61 in which the water molecules are hardly contained, the combination of the HF gas and the water molecules does not occur, and the hydrofluoric acid is hardly generated, and as a result, the thermal oxide film 61 is hardly invaded. In this way, the selective etching of the BPSG film 63 can be performed more reliably.

In the process of FIG. 5, the polysilicon film 62 is etched before the supply of HF gas to remove the BPSG film 63. As described above, when the polysilicon film 62 is etched, the BPSG film 63 can be used as a hard mask, so that the polysilicon film 62 can be more reliably etched into a desired shape.

In the processing of FIG. 5, almost all of the water molecules in the chamber 38 are removed, and the H ₂ O gas is not supplied into the chamber 38. Further, the water molecules contained in the BPSG film 63 in the wafer W are consumed by the reaction of SiO ₂ and hydrofluoric acid, so that the inside of the chamber 38 can be kept extremely dry. As a result, the generation of water marks on the particles or the wafer W caused by the water molecules can be suppressed, and the reliability of the semiconductor device manufactured by the wafer W can be improved.

Further, in the treatment of FIG. 5, when the residue 64 is removed, only the NH ₃ gas is supplied into the chamber 38, but the supplied gas is not limited thereto, and the NH ₃ gas and other gases such as N ₂ may be supplied. a mixture of gases.

Further, in the process of FIG. 5, the selective etching of the BPSG film 63 and the removal of the residue 64 can be performed in the same manner as in the second process module 34. In this way, the miniaturization of the substrate processing system 10 can be achieved.

Hereinafter, a substrate processing system including a substrate processing apparatus according to a second embodiment of the present invention will be described.

The configuration or operation of the present embodiment is basically the same as that of the first embodiment, and only the configuration of the second processing unit is different from that of the first embodiment. Therefore, the description of the same configuration will be omitted, and only the configuration or action different from the first embodiment will be described below.

Fig. 6 is a plan view showing a schematic configuration of a substrate processing system including a substrate processing apparatus according to the embodiment.

In FIG. 6, the substrate processing system 77 includes a first processing unit 11 and a second processing unit 65 (substrate processing apparatus) for performing a specific processing to be described later on the wafer W after the plasma processing of the first processing unit 11; And loading module 13.

The second processing unit 65 includes a second process module 66 for performing a selective etching process to be described later on the wafer W, and a third process module 68 connected to the second process module 66 via a vacuum gate valve 67. It is used to heat the wafer W to be described later, and the second vacuum isolation module 37.

Figure 7 is a cross-sectional view of the second process module of Figure 6, Figure 7 (A) is a cross-sectional view taken along line II-II of Figure 6, and Figure 7 (B) is a portion of Figure A (A) Expand the map. Further, the configuration or function of the second process module 66 is basically the same as that of the second process module 34 of the first embodiment, and only the configuration of the air jet head is different from that of the second process module 34. Therefore, the description of the same configuration or function will be omitted.

In FIG. 7(A), the second process module 66 has a jet head 69 disposed above the chamber 38. The air jet head 69 has a disk-shaped gas supply unit 70 (HF gas supply device), and the gas supply unit 70 has a buffer chamber 71. The buffer chamber 71 communicates with the chamber 38 via a gas vent 72.

Further, the buffer chamber 71 of the gas supply unit 70 of the air jet head 69 is connected to an HF gas supply system that supplies HF gas to the buffer chamber 71. The supplied HF gas is supplied into the chamber 38 through the gas vent 72. The gas supply unit 70 of the air jet head 69 contains a heater (not shown), for example, a heating element that controls the temperature of the HF gas in the buffer chamber 71.

Further, as shown in Fig. 7(B), in the air jet head 69, similarly to the gas vent holes 47, 48 of the air jet head 40, the opening portion in the chamber 38 in the gas vent hole 72 is formed in an end-expanded shape.

Returning to Fig. 6, the third process module 68 has a process chamber container (chamber) 73 in the form of a frame, and a stage heater 74 (substrate heating device) disposed in the chamber 73 as a mounting table for the wafer W. The buffer arm portion 75 is disposed in the vicinity of the stage heater 74 to push up the wafer W placed on the stage heater 74, and a gas introduction portion (not shown) for introducing, for example, N ₂ into the chamber 73. An inert gas of gas.

The stage heater 74 is made of aluminum having an oxide film formed on its surface, and the placed wafer W is heated to a specific temperature by a heater composed of a built-in electric heating wire or the like. The buffer arm portion 75 temporarily avoids the wafer W subjected to the selective etching process from being above the moving track of the second transfer arm portion 37, and causes the wafer W in the second process module 66 or the third process module 68. Smooth replacement is possible.

In the substrate processing system 77, the internal pressure of the loading module 13 is maintained at atmospheric pressure, and the internal pressures of the second processing module 66 and the third processing module 68 are maintained below vacuum or atmospheric pressure. Therefore, the second vacuum isolation module 37 is provided with a vacuum gate valve 76 at its connection portion with the third process module 68.

H ₂ SiF ₆ produced by the reaction of SiO ₂ with hydrofluoric acid is decomposed by heating as follows: H ₂ SiF ₆ + Q (thermal energy) → 2HF + SiF ₄ ↑

Produce HF and SiF ₄ .

In this embodiment, the use of the decomposition of H ₂ SiF ₆ shown in the above formula, so that the reaction of SiO ₂ and hydrofluoric acid residue of H ₂ SiF ₆ produced by the thermal decomposition is removed.

The substrate processing method of this embodiment will be described below.

8 is a flow chart of a substrate processing method performed by the substrate processing system of FIG. 6.

First, step S51 of the process of FIG. 5 is performed. Thereafter, the wafer W is carried out from the chamber of the first process module 25, and is carried into the chamber 38 of the second process module 66 via the loading module 13. At this time, the wafer W is placed on the mounting table 39.

Thereafter, in step S52 of the process of FIG. 5, the wafer W is carried out from the chamber 38 of the second process module 66, and the wafer W is carried into the chamber 73 of the third process module 68. At this time, the wafer W is placed on the stage heater 74. The substrate W is heated by the stage heater 74 to a specific temperature of the substrate W processing apparatus, specifically, 150 ° C or more (substrate heating step) (step S81). Further, the gas introduction unit introduces N ₂ gas into the chamber 73, and the introduced N ₂ gas forms a gas flow in accordance with the pressure reduction of the TMP 41. At this time, H ₂ SiF ₆ constituting the residue 64 is decomposed into HF and SiF ₄ by heating, and the decomposed HF and SiF ₄ are taken up into the gas stream and removed.

Thereafter, the wafer W is carried out from the chamber 73 of the third process module 68, and the process is terminated.

According to the process of FIG. 8, the wafer W having the thermal oxide film 61 and the BPSG film 63 is supplied with HF gas, and the wafer W is heated. The fluoric acid generated by the HF gas causes the BPSG film 63 to be selectively etched, but a residue 64 composed of H ₂ SiF ₆ is generated. This residue 64 is decomposed into HF and SiF ₄ by heating. Therefore, the residue 64 can be removed by thermal decomposition. In this way, the residue 64 composed of H ₂ SiF ₆ can be easily removed.

In the processing of FIG. 8, the HF gas is supplied to the wafer W and the heating of the wafer W is performed in an individual process module, but the processing may be performed in one process module, specifically, As shown in FIG. 9, a heater 78 is disposed in the mounting table 39 of the second process module 66, and after the BPSG film 63 is removed by the hydrofluoric acid in the chamber 38, the wafer W is not carried out from the chamber 38. On the mounting table 39, the wafer W is heated by the heater 78 to 150 ° C or higher. H ₂ SiF ₆ produced by the reaction of SiO ₂ with hydrofluoric acid can be decomposed above 150 °C. Therefore, H ₂ SiF ₆ can be surely removed by decomposing H ₂ SiF ₆ into HF and SiF ₄ by heating.

In the process of FIG. 8, when the wafer W is heated, N ₂ gas is introduced into the chamber 73 to form a gas flow. Therefore, the decomposed HF and SiF ₄ are caught in the gas flow and can be surely removed.

In the above embodiments, the selective etching of the BPSG film 63 is described. However, the oxide film to be selectively etched is not limited thereto, and may be an oxide film containing at least more impurities than the thermal oxide film 61. It may be a TEOS (Tetra Ethyl Ortho Silicate) film or a BPS (Bron Silicate Glass) film. Further, the residue to be removed is not limited to H ₂ SiF ₆ , and the present invention can be applied as long as it is removed by removal of an oxide film of hydrofluoric acid.

Further, the substrate processing system including the substrate processing apparatus according to each embodiment is described in which two processing units are arranged in parallel, but the configuration of the substrate processing system is not limited thereto, and specifically, it may be a plurality of processing modules. Arranged in a columnar configuration or in a group configuration.

The substrate to be processed in the process of FIG. 5 or the process of FIG. 8 is not limited to the wafer for a semiconductor device, and may be any substrate or mask used for LCD or FPD (Flat Panel Display), a CD substrate, a printer plate, or the like.

It is an object of the present invention to provide a software program for realizing the functions of the above embodiments in a memory medium, and to supply the memory medium to a system or device, and the computer (or CPU, MPU, etc.) of the system or device reads the memory. This is achieved by executing the code of the memory medium.

In this case, the code itself read by the memory medium is a function for realizing the above embodiments, and the code and the memory medium for storing the code constitute the present invention.

Further, the memory medium to which the program code is supplied may be, for example, a floppy disk (registered trademark), a hard disk, an optical disk, a CD-ROM, a CD-R, a CD-RW, a DVD-ROM, a DVD-RAM, or a DVD-RW. , DVD, RW, etc., optical discs, non-volatile memory cards, ROM, etc. Also, the code can be downloaded via the Internet.

Moreover, not only by executing the program code read by the computer, but also by implementing the functions of the above embodiments, the OS (operating system) and the like on the computer are actually processed in part or in whole according to the instruction of the code. The case where the functions of the respective embodiments are realized by this processing is also included.

Moreover, the code read by the memory medium is written into the memory expansion board of the computer or the memory of the function expansion module connected to the computer, and the expansion function is applied to the expansion board according to the instruction of the code. The CPU or the like provided in the function expansion module performs part or all of the actual processing, and the functions of the above embodiments are also included in the processing.

(effect of the invention)

The substrate processing method according to the first aspect of the invention, and the substrate processing apparatus according to claim 7 are a substrate supply having a first oxide film formed by thermal oxidation treatment and a second oxide film containing impurities. The HF gas is supplied to the substrate with a purge gas containing at least NH ₃ gas. The fluoric acid produced by the HF gas selectively etches the second oxide film, but generates a residue. The NH ₃ gas reacts with the residue to produce a substance that is easily sublimed. Therefore, the residue can be removed by reaction and sublimation with NH ₃ gas. In this way, it is easy to remove the residue caused by the hydrofluoric acid.

Patent application range of the substrate according to processing method of the second item, the step of supplying HF gas to the H ₂ O gas is not supplied, thus almost no oxide film of the first H ₂ O, almost no HF gas and the H ₂ O The combination does not generate hydrofluoric acid, so the first oxide film is hardly etched. Therefore, the second oxide film can be selectively etched selectively.

According to the substrate processing method of claim 3, the ruthenium-containing layer is etched before the HF gas supply. In this manner, when the ruthenium-containing layer is etched, the second oxide film can be used as a hard mask, so that the ruthenium-containing layer can be surely etched into a desired shape.

The substrate processing method according to the fourth aspect of the invention, and the substrate processing apparatus according to claim 8 are a substrate supply having a first oxide film formed by thermal oxidation treatment and a second oxide film containing impurities. The HF gas is used to heat the substrate again. The fluoric acid produced by the HF gas selectively etches the second oxide film, but generates a residue. The residue is decomposed and sublimated by heating. Therefore, the residue can be removed by decomposition by heating. In this way, it is easy to remove the residue caused by the hydrofluoric acid.

According to the substrate processing method of claim 5, the substrate is heated in a N ₂ gas atmosphere. The N ₂ gas forms a gas stream, and can be entangled and transported to the decomposed residue. In this way, the residue caused by the hydrofluoric acid can be surely removed.

According to the substrate processing method of claim 6, the substrate is heated to 150 ° C or higher. The residue caused by hydrofluoric acid is decomposed above 150 °C. Therefore, the residue caused by the hydrofluoric acid can be surely removed.

W. . . Wafer

10, 77. . . Substrate processing system

11. . . First process department

12, 65. . . Second process department

13. . . Loading module

14. . . FOUP

15. . . FOUP mounting table

16. . . Locator

17. . . 1IMS

18. . . 2IMS18

25. . . First process module

34. . . 2nd process module

38. . . Chamber

39. . . Mounting table

40. . . Jet head

43. . . Lower gas supply

44. . . Upper gas supply

60. . . Bismuth substrate

61. . . Thermal oxide film

62. . . Polycrystalline germanium film

63. . . BPSG film

64. . . the remains

68. . . 3rd process module

74. . . Platform heater

1 is a plan view showing a schematic configuration of a substrate processing system including a substrate processing apparatus according to a first embodiment of the present invention.

Figure 2 is a cross-sectional view of the second process module of Figure 1, Figure 2 (A) is a cross-sectional view taken along line I-I of Figure 1, and Figure 2 (B) is a portion of Figure A (A) Expand the map.

3 is a drawing of a substrate processing method performed by the substrate processing system of FIG. 1.

Fig. 4 is a graph showing the relationship between the type of oxide film and the etching rate.

FIG. 5 is a flow chart of a substrate processing method performed by the substrate processing system of FIG. 1. FIG.

Fig. 6 is a plan view showing a schematic configuration of a substrate processing system including a substrate processing apparatus according to a second embodiment of the present invention.

Figure 7 is a cross-sectional view of the second process module of Figure 6, Figure 7 (A) is a cross-sectional view taken along line II-II of Figure 6, and Figure 7 (B) is a portion of Figure A (A) Expand the map.

8 is a flow chart of a substrate processing method performed by the substrate processing system of FIG. 6.

Figure 9 is a cross-sectional view showing a modification of the second process module of Figure 7.

W. . . Wafer

60. . . Bismuth substrate

61. . . Thermal oxide film

62. . . Polycrystalline germanium film

63. . . BPSG film

64. . . the remains

Claims (8)

A substrate processing method for processing a substrate having: a first oxide film formed by thermal oxidation treatment in a processing chamber; and a second oxide film containing impurities; and characterized in that: a step of removing water molecules in the chamber, supplying HF gas to the substrate, and modifying the second oxide film into a residue; and supplying the substrate containing the first oxide film and the residue to at least NH ₃ gas. A cleaning gas supply step of the cleaning gas. The substrate processing method according to claim 1, wherein the H ₂ O gas is not supplied in the HF gas supply step. The substrate processing method according to claim 1 or 2, wherein the substrate has a ruthenium-containing layer formed on the first oxide film and covered by the second oxide film, and a part of the second oxide film is exposed The ruthenium-containing layer is etched before the HF gas supply step. A substrate processing method for processing a substrate having a first oxide film formed by thermal oxidation treatment and a second oxide film containing impurities, wherein the substrate is provided with an HF gas supply step for Supplying HF gas to the substrate; and a substrate heating step for heating the above-mentioned HF gas supplied thereto Substrate. The substrate processing method according to claim 4, wherein in the substrate heating step, the substrate is heated in an N ₂ gas atmosphere. The substrate processing method of claim 4, wherein the substrate is heated to 150 ° C or higher in the substrate heating step. A substrate processing apparatus for processing a substrate, the substrate having a first oxide film formed by thermal oxidation treatment and a second oxide film containing impurities, wherein the substrate is provided with an HF gas supply device for The HF gas is supplied to the substrate; and the cleaning gas supply device supplies a cleaning gas containing at least NH ₃ gas to the substrate to which the HF gas is supplied. A substrate processing apparatus for processing a substrate, the substrate having a first oxide film formed by thermal oxidation treatment and a second oxide film containing impurities, wherein the substrate is provided with an HF gas supply device for An HF gas is supplied to the substrate; and a substrate heating device for heating the substrate to which the HF gas is supplied.