JP4849614B2 - Substrate processing method and substrate processing system - Google Patents

Description

  The present invention relates to a substrate processing method and a substrate processing system, and more particularly to a substrate processing method for removing a hard mask and a deposition film from a substrate.

A thermal oxide film 72 made of SiO ₂ , various films 73 and 74, and an oxide film containing impurities such as a BPSG (Boron Phosphorous Silicate Glass) film 75 are sequentially laminated on a single crystal silicon substrate 71 as shown in FIG. A wafer W for semiconductor devices is known. When holes or trenches are formed in the single crystal silicon substrate 71 in the wafer W, a halogen-based processing gas, for example, HBr (hydrogen bromide) gas, is used with the BPSG film 75 as a hard mask in a reduced pressure environment. The single crystal silicon substrate 71 is dry-etched using plasma generated from the above. At this time, the plasma and silicon (Si) react to form a deposition film 76 made of SiOBr on the surface of a hole or the like. The deposition film 76 has a function of suppressing dry etching of the single crystal silicon substrate 71.

The BPSG film 75 and the deposition film 76 need to be removed because they cause a conduction failure in a semiconductor device manufactured from the wafer W. In particular, wet etching is used as a method for removing the hard mask such as the BPSG film 75. (For example, refer to Patent Document 1).
JP 2005-150597 A

  However, since wet etching uses a chemical solution, the wet etching apparatus and the dry etching apparatus that performs the dry etching process on the wafer W under a reduced pressure environment cannot be arranged in the same substrate processing system. Therefore, it is necessary to install the wet etching apparatus in a different place from the dry etching apparatus. In addition, after forming a hole or the like in the single crystal silicon substrate 71 with a dry etching apparatus, it is necessary to carry out the wafer W from the dry etching apparatus, carry the wafer W in the atmosphere, and carry it into the wet etching apparatus. . As a result, the substrate processing step is complicated.

  Further, since the deposition film 76 made of SiOBr may react with moisture in the atmosphere during the transfer of the wafer W in the atmosphere, the time (Q-Time) for exposing the wafer W to the atmosphere is managed. It is necessary to minimize it. This exposure time management requires considerable man-hours.

  That is, by removing the BPSG film 75 and the deposition film 76, the productivity of the semiconductor device from the wafer W is deteriorated.

  An object of the present invention is to provide a substrate processing method and a substrate processing system capable of preventing deterioration of productivity of a semiconductor device from a substrate.

In order to achieve the above object, a substrate processing method according to claim 1 includes a single crystal silicon base material, a first oxide film formed by thermal oxidation treatment, and a second oxide film containing impurities, The first and second oxide films are substrate processing methods in which a substrate exposing a part of the single crystal silicon base material is processed in a chamber, wherein the exposed single crystal silicon base material is exposed by plasma of a halogen-based gas. A plasma etching step for etching, a water molecule removing step for removing water molecules from the chamber, and an HF gas is supplied toward the substrate to form the second oxide film and the plasma etching step on the substrate. HF gas supply step for transforming the deposited film into a residue, and at least toward the substrate on which the first oxide film and the residue are present simultaneously. And having a cleaning gas supplying step of supplying a cleaning gas containing NH ₃ gas.

The substrate processing method according to claim 2 is characterized in that, in the substrate processing method according to claim 1 , the substrate is not exposed to the atmosphere during the plasma etching step, the HF gas supply step, and the cleaning gas supply step. And

In order to achieve the above object, a substrate processing system according to claim 3 includes a single crystal silicon substrate, a first oxide film formed by thermal oxidation, and a second oxide film containing impurities, The first and second oxide films are substrate processing systems for processing in a chamber a substrate from which a part of the single crystal silicon base material is exposed, wherein the exposed single crystal silicon base material is exposed to plasma of a halogen-based gas. a plasma etching apparatus for etching, while removing water molecules from the chamber, by supplying HF gas toward the front Stories substrate, formed on said substrate by said second oxide film and the plasma etching apparatus depot HF gas supply device for transforming the film into a residue, and at least NH ₃ gas toward the substrate on which the first oxide film and the residue are present simultaneously And a cleaning gas supply device for supplying a cleaning gas.

A substrate processing system according to claim 4 is the substrate processing system according to claim 3 , which is disposed between the plasma etching apparatus, the HF gas supply apparatus, and the cleaning gas supply apparatus, and exposes the substrate to the atmosphere. And a substrate transfer device that transfers the substrate without any problem.

According to the substrate processing method according to claim 1, wherein and claim 3 substrate processing system according single part by a second oxide layer comprising a first oxide film and impurities formed by thermal oxidation is exposed The crystalline silicon substrate is etched by plasma of a halogen-based gas, water molecules are removed from the chamber, HF gas is supplied toward the substrate, and the second oxide film and the deposition formed on the substrate in the plasma etching step The film is transformed into a residue. Further, a cleaning gas containing at least NH ₃ gas is supplied toward the substrate on which the first oxide film and the residue are present simultaneously. When the single crystal silicon substrate is etched by the plasma of the halogen-based gas, a deposition film is formed. The hydrofluoric acid generated from the HF gas selectively etches the deposition film and the second oxide film, but generates a residue. NH ₃ gas reacts with the residue to produce an easily sublimated reaction product, which is easily sublimated. Therefore, since the deposition film and the second oxide film can be removed in a dry environment, the apparatus for etching the single crystal silicon base material and the apparatus for removing the deposition film and the second oxide film are processed in the same substrate processing. Can be placed in the system. Accordingly, the deposition film and the second oxide film can be removed without exposing the substrate to the atmosphere after etching the single crystal silicon base material, and the substrate processing process can be simplified. The need to manage the time of exposure to the atmosphere can be eliminated. As a result, it is possible to prevent the productivity of the semiconductor device from the substrate from deteriorating.

According to the substrate processing method as set forth in claim 2 and the substrate processing system as set forth in claim 4, during the etching by halogen-based gas plasma, the supply of HF gas toward the substrate, and the supply of cleaning gas toward the substrate. The substrate is not exposed to the atmosphere. Therefore, it is possible to reliably eliminate the need to manage the time for exposing the substrate to the atmosphere.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

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

  FIG. 1 is a plan view showing a schematic configuration of a substrate processing system according to the present embodiment.

  In FIG. 1, a substrate processing system 10 includes a transfer module 11 (substrate transfer device) having a hexagonal shape in plan view, two plasma process modules 12 and 13 connected to one side surface of the transfer module 11, and the two plasma processes. Two plasma process modules 14 and 15 (plasma etching apparatus) connected to the other side of the transfer module 11 so as to face the modules 12 and 13 (plasma etching apparatus), and adjacent to the plasma process module 13 and to the transfer module 11 A gas process module 16 (HF gas supply device) to be connected, a heating process module 17 (substrate heating device) adjacent to the plasma process module 15 and connected to the transfer module 11, and a rectangular transfer chamber Comprises a chromatography Zehnder module 18, and a transfer module 11 and two load-lock modules 19 and 20 connecting these are arranged between the loader module 18.

  The transfer module 11 has a transfer arm 21 that can be bent and extended and disposed therein, and the transfer arm 21 includes a plasma process module 12 to 15, a gas process module 16, a heating process module 17, and a load / lock module 19. , 20 is transferred.

  Each of the plasma process modules 12 to 15 has a processing chamber container (chamber) for accommodating the wafer W, and a halogen-based processing gas, for example, HBr gas is introduced into the chamber to generate an electric field inside the chamber. Plasma is generated from the introduced processing gas, and the wafer W is etched by the plasma. Specifically, the single crystal silicon substrate 71 is etched on the wafer W shown in FIG.

  2 is a cross-sectional view of the gas process module in FIG. 1, FIG. 2 (A) is a cross-sectional view along line II in FIG. 1, and FIG. 2 (B) is a portion A in FIG. 2 (A). FIG.

  In FIG. 2A, the gas process module 16 opposes the processing chamber container (chamber) 22, the mounting table 23 for the wafer W disposed in the chamber 22, and the mounting table 23 above the chamber 22. As a variable butterfly valve that is disposed between the chamber 22 and the TMP 25a and that controls the pressure in the chamber 22, the shower head 24 disposed in the chamber, the TMP (Turbo Molecular Pump) 25a that exhausts gas in the chamber 22, and the like. APC (Adaptive Pressure Control) valve 25b.

  The shower head 24 includes a disk-shaped gas supply unit 26, and the gas supply unit 26 has a buffer chamber 27 inside. The buffer chamber 27 communicates with the chamber 22 through the gas vent hole 28. The buffer chamber 27 in the gas supply unit 26 of the shower head 24 is connected to an HF gas supply system (not shown). The HF gas supply system supplies HF gas to the buffer chamber 27. The supplied HF gas is supplied into the chamber 22 through the gas vent hole 28.

  In the shower head 24, as shown in FIG. 2B, the opening into the chamber 22 in the gas vent hole 28 is formed in a divergent shape. Thereby, HF gas can be efficiently diffused into the chamber 22. Further, since the gas vent hole 28 has a constricted cross section, the residue generated in the chamber 22 is prevented from flowing back to the gas vent hole 28 and then to the buffer chamber 27.

  In the gas process module 16, the side wall of the chamber 22 incorporates a heater (not shown), for example, a heating element. The heating element in the side wall prevents the residue generated when removing the BPSG film 75 and the deposition film 76 with hydrofluoric acid from adhering to the inside of the side wall by heating the side wall.

  The mounting table 23 has a refrigerant chamber (not shown) inside as a temperature control mechanism. A coolant having a predetermined temperature, for example, cooling water or a Galden (registered trademark) liquid, is supplied to the coolant chamber, and the temperature of the wafer W mounted on the upper surface of the mounting table 23 is controlled by the temperature of the coolant.

  Returning to FIG. 1, the heating process module 17 includes a processing chamber container (chamber) that accommodates the wafer W, and the chamber includes a halogen lamp, a sheet heater, and the like, and heats the accommodated wafer W.

  The inside of the transfer module 11, the plasma process modules 12 to 15, the gas process module 16 and the heating process module 17 is maintained in a reduced pressure state, and the transfer module 11, the plasma process modules 12 to 15, the gas process module 16 and the heating process module 17 are maintained. Are connected via vacuum gate valves 12a to 17a.

  In the substrate processing system 10, the internal pressure of the loader module 18 is maintained at atmospheric pressure, while the internal pressure of the transfer module 11 is maintained at vacuum. Therefore, each load / lock module 19, 20 is provided with a vacuum gate valve 19 a, 20 a at a connection portion with the transfer module 11 and an atmospheric door valve 19 b, 20 b at a connection portion with the loader module 18. It is configured as a vacuum preliminary transfer chamber that can adjust the internal pressure. Each load / lock module 19, 20 has a wafer mounting table 19 c, 20 c for temporarily mounting the wafer W delivered between the loader module 18 and the transfer module 11.

  The loader module 18 includes three FOUP mounting tables 30 on which FOUPs (Front Opening Unified Pods) 29 as containers for storing 25 wafers W are mounted, in addition to the load / lock modules 19 and 20, and the FOUPs. An orienter 31 that pre-aligns the position of the wafer W unloaded from the 29 and a first and second IMS (Integrated Metrology System, Therma-Wave, Inc.) 32 and 33 that measure the surface state of the wafer W are connected. Has been.

  The load / lock modules 19 and 20 are connected to the side wall along the longitudinal direction of the loader module 18 and are disposed so as to face the three hoop mounting tables 30 with the loader module 18 interposed therebetween. The first IMS 32 is disposed at the other end in the longitudinal direction of the loader module 18, and the second IMS 33 is disposed in parallel with the three hoop mounting tables 30.

  The loader module 18 includes a scalar type dual arm type transfer arm 34 for transferring the wafer W disposed therein, and 3 as an inlet for the wafer W disposed on the side wall so as to correspond to each hoop mounting table 30. And two load ports 35. The transfer arm 34 takes out the wafer W from the FOUP 29 placed on the FOUP placement table 30 via the load port 35, and removes the taken wafer W from the load / lock modules 19, 20, the orienter 31, the first IMS 32 and the first IMS 32. Carry in and out of 2 IMS33.

  The first IMS 32 is an optical system monitor, and includes a mounting table 36 on which the loaded wafer W is mounted, and an optical sensor 37 that directs the wafer W mounted on the mounting table 36. The surface shape, for example, the film thickness of the surface layer, and the CD (Critical Dimension) value of the wiring trench, the gate electrode, etc. are measured. The second IMS 33 is also an optical system monitor, and has a mounting table 38 and an optical sensor 39 as in the first IMS 32, and measures the number of particles on the surface of the wafer W, for example.

  Further, the substrate processing system 10 includes an operation panel 40 disposed at one end in the longitudinal direction of the loader module 18. The operation panel 40 has a display unit made up of, for example, an LCD (Liquid Crystal Display), and the display unit displays the operation status of each component of the substrate processing system 10.

By the way, in order to arrange an apparatus for removing the BPSG film 75 and the deposit film 76 in the substrate processing system 10 on the wafer W as shown in FIG. 7, the BPSG film 75 and the deposit film 76 are removed in a dry environment. There is a need. Further, since the BPSG film 75 is a silicon-based oxide film, the deposition film 76 is a pseudo-SiO ₂ film made of SiOBr, and the thermal oxide film 72 is also a SiO ₂ film, the BPSG film 75 and the deposition film 76 are removed. The method may also remove the thermal oxide film 72. When the thermal oxide film 72 is removed, a portion corresponding to the thermal oxide film 72 in the hole or trench may be recessed and notching may occur. Therefore, it is necessary to remove the BPSG film 75 and the deposition film 76 with a high selection ratio with respect to the thermal oxide film 72.

The present inventor conducted various experiments in order to find a method for removing the BPSG film 75 and the deposition film 76 that satisfy the above-described requirements, and supplies H ₂ O gas in an environment in which almost no H ₂ O exists. In the case where only the HF gas is supplied toward the wafer W, it is discovered that the BPSG film 75 and the deposition film 76 can be removed, and the selectivity of the BPSG film 75 and the deposition film 76 to the thermal oxide film 72 is increased to 1000. I found that it can be enhanced.

  And this inventor earnestly researched about the mechanism of the said removal method, and came to analogize the hypothesis demonstrated below.

The HF gas becomes hydrofluoric acid when combined with H ₂ O, and the hydrofluoric acid invades and removes the oxide film. Here, in order that the HF gas becomes hydrofluoric acid in a dry environment in which almost no H ₂ O exists, it is necessary to associate with water (H ₂ O) molecules contained in the oxide film.

  Since the BPSG film 75 is formed by vapor deposition such as a CVD process, and the deposition film 76 is formed by a reaction between plasma and silicon, the film structure is sparse and water molecules are easily adsorbed. Therefore, the BPSG film 75 and the deposition film 76 contain water molecules to some extent. The HF gas that has reached the BPSG film 75 and the deposition film 76 is combined with the water molecules to form hydrofluoric acid. The hydrofluoric acid invades the BPSG film 75 and the deposit film 76. Thereby, the BPSG film 75 and the deposition film 76 can be removed without using a chemical solution and plasma.

  On the other hand, since the thermal oxide film 72 is formed by a thermal oxidation process in an environment of 800 to 900 ° C., it does not contain water molecules at the time of film formation, and the film structure is dense, so that water molecules are adsorbed. Hard to do. Therefore, the thermal oxide film 72 contains almost no water molecules. Even if the supplied HF gas reaches the thermal oxide film 72, it does not become hydrofluoric acid because there are no water molecules. As a result, the thermal oxide film 72 is not attacked.

Accordingly, when only HF gas is supplied toward the wafer W without supplying H ₂ O gas in a dry environment in which almost no H ₂ O exists, the BPSG film 75 and the deposition film 76 on the thermal oxide film 72 are The selectivity is increased (for example, the selectivity is 1000), and the BPSG film 75 and the deposition film 76 are selectively etched.

By the way, when removing the BPSG film 75 and the deposition film 76 with hydrofluoric acid, the SiO ₂ and hydrofluoric acid (HF) in the BPSG film 75 and the deposition film 76 cause a chemical reaction represented by the following formula,
SiO ₂ + 4HF → SiF ₄ + 2H ₂ O ↑
SiF ₄ + 2HF → H ₂ SiF ₆
Residue (H ₂ SiF ₆ ) is generated. This residue also needs to be removed to cause a conduction failure in the semiconductor device.

  On the other hand, in this embodiment, thermal energy is used to remove the residue. Specifically, by heating the wafer W on which the residue is generated, the residue is pyrolyzed as shown in the following formula.

H ₂ SiF ₆ + Q (thermal energy) → 2HF ↑ + SiF ₄ ↑
That is, in this embodiment, H ₂ SiF ₆ that is a residue of the reaction of SiO ₂ and hydrofluoric acid is removed by heating.

  Next, the substrate processing method according to the present embodiment will be described.

  FIG. 3 is a process diagram showing a substrate processing method executed by the substrate processing system of FIG.

  First, a thermal oxide film 72, various films 73 and 74, and a BPSG film 75 are laminated on the single crystal silicon base material 71, and the single crystal silicon base material 71 is formed by the thermal oxide film 72, various films 73 and 74, and the BPSG film 75. A wafer W to be partially exposed is prepared, and the wafer W is loaded into any one of the plasma process modules 12 to 15. Then, in the plasma process module into which the wafer W is loaded, holes and trenches are formed in the single crystal silicon substrate 71 of the wafer W by plasma generated from the HBr gas (plasma etching step). At this time, a deposition film 76 is formed in the hole or trench of the wafer W (FIG. 3A).

Next, the wafer W shown in FIG. 3A is unloaded from the chamber of the plasma process module, and loaded into the chamber 22 of the gas process module 16 via the transfer module 11. Then, the wafer W is mounted on the mounting table 23, and the pressure in the chamber 22 is set to 1.3 × 10 ^{1 to} 1.1 × 10 ³ Pa ( ^{1 to} 8 Torr) by the APC valve 25 b or the like. The atmospheric temperature inside is set to 40 to 60 ° C. by the heater inside the side wall. Then, HF gas is supplied from the gas supply unit 26 of the shower head 24 toward the wafer W at a flow rate of 40 to 60 SCCM (HF gas supply step) (FIG. 3B). At this time, water molecules are almost removed from the chamber 22 and the H ₂ O gas is not supplied into the chamber 22.

Here, the HF gas reaching the BPSG film 75 and the deposition film 76 is combined with water molecules contained in the BPSG film 75 and the deposition film 76 to become hydrofluoric acid. Then, the hydrofluoric acid will attack the BPSG film 75 and the deposit film 76, as a result, although the BPSG film 75 and the deposit film 76 is selectively etched, SiO ₂ and fluoride in the BPSG film 75 and the deposit film 76 Residue 41 based on the reaction with the acid is generated and deposited on the various films 73 and 74, the thermal oxide film 72, and the single crystal silicon substrate 71 in the holes and trenches (FIG. 3C).

Next, the wafer W on which the residue 41 is deposited is unloaded from the chamber 22 of the gas process module 16 and loaded into the chamber of the heating process module 17 via the transfer module 11. The heating process module 17 heats the loaded wafer W to a predetermined temperature, specifically, 150 ° C. or more (substrate heating step). The heating process module 17 introduces N ₂ gas into the chamber, and the introduced N ₂ gas forms a gas flow in the chamber. At this time, H ₂ SiF ₆ constituting the residue 41 is decomposed into HF and SiF ₄ by heating, and the decomposed HF and SiF ₄ are entrained in the gas flow and removed (FIG. 3D).

  Next, the wafer W is unloaded from the chamber 22 of the heating process module 17 and the present process is terminated.

According to the substrate processing method according to the present embodiment, the single crystal silicon base material 71 partially exposed by the thermal oxide film 72, the various films 73 and 74, and the BPSG film 75 in the wafer W is etched by the plasma of HBr gas. Then, HF gas is supplied toward the wafer W, and the wafer W is further heated. When the single crystal silicon substrate 71 is etched by the plasma of HBr gas, a deposition film 76 is formed. The hydrofluoric acid generated from the HF gas selectively etches the deposition film 76 and the BPSG film 75, but generates a residue 41 (H ₂ SiF ₆ ). The residue 41 is decomposed into HF and SiF ₄ by heating. Therefore, since the deposition film 76 and the BPSG film 75 can be removed in a dry environment, the gas process module 16 and the heating process module 17 can be arranged in one substrate processing system 10. Thereby, after etching the single crystal silicon substrate 71, the wafer W can be transferred to the gas process module 16 and the heating process module 17 via the transfer module 11. That is, the deposition film 76 and the BPSG film 75 can be removed without exposing the wafer W to the atmosphere, the substrate processing process can be simplified, and the time for exposing the wafer W to the atmosphere is managed. The need can be eliminated. As a result, it is possible to prevent the productivity of the semiconductor device from deteriorating.

  According to the substrate processing method described above, the gas process module 16 and the heating process module 17 can be arranged in one substrate processing system 10, and therefore the gas process module 16 and the heating process module 17 are installed in different locations. There is no need, and the system installation area (footprint) can be reduced.

Further, according to the substrate processing method described above, the wafer W is heated in an N ₂ gas atmosphere. The N ₂ gas forms a gas flow and entrains and transports the residue 41 decomposed by heating. Therefore, the deposition film 76 and the BPSG film 75 can be reliably removed.

  Further, according to the substrate processing method described above, the HF gas is supplied toward the wafer W having the BPSG film 75 and the deposition film 76. The HF gas is combined with water molecules contained in the BPSG film 75 and the deposit film 76 to form hydrofluoric acid, and the hydrofluoric acid invades and selectively etches the BPSG film 75 and the deposit film 76. Therefore, when the BPSG film 75 and the deposition film 76 are removed, it is possible to prevent the thermal oxide film 72 from being removed and the occurrence of notching.

  In the substrate processing system 10 described above, the gas process module 16 and the heating process module 17 are realized by separate apparatuses. However, as shown in FIG. 4, the stage heater 43 in which the gas process module 42 is arranged in the mounting table 23. And the stage heater 43 may heat the wafer W mounted on the mounting table 23. Thereby, the selective etching of the BPSG film 75 and the deposit film 76 and the thermal decomposition of the residue 41 can be performed only by the gas process module 42. That is, since the functions of the gas process module and the thermal process module can be realized by one process module, the substrate processing system 10 can be reduced in size.

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

  This embodiment is basically the same in configuration and operation as the first embodiment described above, and only differs from the first embodiment described above in that the thermal decomposition of the residue is not used. . Therefore, the description of the same configuration is omitted, and only the configuration and operation different from the first embodiment will be described below.

As described above, when the BPSG film 75 and the deposition film 76 are removed with hydrofluoric acid, the BPSG film 75 or the deposition film 76 and hydrofluoric acid cause a chemical reaction to generate a residue 41 (H ₂ SiF ₆ ). In the present embodiment, NH ₃ is used to remove the residue 41. Specifically, by supplying NH ₃ gas toward the residue, a chemical reaction represented by the following formula occurs,
H ₂ SiF ₆ + 2NH ₃ → 2NH ₄ F + SiF ₄ ↑
NH ₄ F (ammonium fluoride) and SiF ₄ are generated. NH ₄ F is a reaction product that is easily sublimated, and can be easily removed because it sublimes if the ambient temperature is set slightly higher than room temperature.

That is, in this embodiment, H ₂ SiF ₆ that is a residue of the reaction between SiO ₂ and hydrofluoric acid is removed through reaction with NH ₃ and sublimation.

The substrate processing system according to the present embodiment has the same configuration as that of the substrate processing system 10 of FIG. 1, and selectively etches the BPSG film 75 and the deposition film 76 instead of the gas process module 16 and the heating process module 17. And a gas process module 44 (HF gas supply device, cleaning gas supply device) that performs the reaction of the residue 41 and NH ₃ and the sublimation of the reaction product (NH ₄ F) generated by the reaction. The gas process module 44 is connected to the transfer module 11 via a vacuum gate valve 44a.

  FIG. 5 is a cross-sectional view of the gas process module in the substrate processing system according to the present embodiment.

  In FIG. 5, the gas process module 44 includes a chamber 22, a mounting table 23, a shower head 45, a TMP 25a, and an APC valve 25b.

  The shower head 45 includes a disk-shaped lower gas supply unit 46 and a disk-shaped upper gas supply unit 47, and the upper gas supply unit 47 is superimposed on the lower gas supply unit 46. The lower gas supply unit 46 and the upper gas supply unit 47 have a first buffer chamber 48 and a second buffer chamber 49, respectively. The first buffer chamber 48 and the second buffer chamber 49 communicate with the chamber 22 through gas vents 50 and 51, respectively.

The first buffer chamber 48 is connected to an NH ₃ (ammonia) gas supply system (not shown). The NH ₃ gas supply system supplies a gas containing NH ₃ gas (cleaning gas) to the first buffer chamber 48. The supplied cleaning gas is supplied into the chamber 22 through the gas vent 50. The second buffer chamber 49 is connected to the HF gas supply system. The HF gas supply system supplies HF gas to the second buffer chamber 49. The supplied HF gas is supplied into the chamber 22 through the gas vent hole 51.

  Openings into the chamber 22 in the gas vent holes 50 and 51 are formed in a divergent shape like the gas vent hole 28 in FIG. Thereby, the cleaning gas or the HF gas can be efficiently diffused into the chamber 22. Further, since the gas vent holes 50 and 51 have a constricted cross section, the residue generated in the chamber 22 is pulled into the gas vent holes 50 and 51, and hence the first buffer chamber 48 and the second buffer chamber 49. Prevent backflow.

In the gas process module 44, the side wall of the chamber 22 incorporates a heater (not shown), for example, a heating element. Thereby, the atmospheric temperature in the chamber 22 can be set higher than normal temperature, and the sublimation of NH ₄ F described later can be promoted.

  Next, the substrate processing method according to the present embodiment will be described.

  FIG. 6 is a process diagram showing a substrate processing method executed by the substrate processing system according to the present embodiment.

  First, as in FIG. 3A, the wafer W is loaded into any one of the plasma process modules 12 to 15, and the plasma generated from the HBr gas in the plasma process module into which the wafer W is loaded, Holes and trenches are formed in the single crystal silicon substrate 71 of the wafer W (plasma etching step). At this time, a deposition film 76 is formed in the hole or trench of the wafer W (FIG. 6A).

Next, the wafer W shown in FIG. 6A is unloaded from the chamber of the plasma process module, and loaded into the chamber 22 of the gas process module 44 via the transfer module 11. Then, the wafer W is mounted on the mounting table 23, and the pressure in the chamber 22, the atmospheric temperature in the chamber 22, and the supply flow rate of the HF gas from the upper gas supply unit 47 are set in the same manner as in FIG. (HF gas supply step). At this time, as in FIG. 3B, the water molecules are substantially removed from the chamber 22 and the H ₂ O gas is not supplied into the chamber 22.

Here, as in FIG. 3C, a residue 41 is generated based on the reaction between SiO ₂ and hydrofluoric acid in the BPSG film 75 and the deposit film 76, and various films 73 and 74, heat in the holes and trenches. Deposited on the oxide film 72 and the single crystal silicon substrate 71 (FIG. 6C).

Next, after the supply of the HF gas into the chamber 22 is stopped, the cleaning gas is supplied from the lower layer gas supply unit 46 of the shower head 45 toward the wafer W (cleaning gas supply step) (FIG. 6D). At this time, NH ₃ gas in the cleaning gas reacts with H ₂ SiF ₆ constituting the residue 41 to generate NH ₄ F and SiF ₄ . Then, the atmospheric temperature in the chamber 22 is set to be slightly higher than the normal temperature by a heating element or the like in the side wall, and NH ₄ F is sublimated (FIG. 6E).

  Next, the wafer W is unloaded from the chamber 22 of the gas process module 44, and this process is terminated.

According to the substrate processing method according to the present embodiment, the single crystal silicon base material 71 partially exposed by the thermal oxide film 72, the various films 73 and 74, and the BPSG film 75 in the wafer W is etched by the plasma of HBr gas. Then, HF gas is supplied toward the wafer W, and further, a cleaning gas containing NH ₃ gas is supplied toward the wafer W. When the single crystal silicon substrate 71 is etched by the plasma of HBr gas, a deposition film 76 is formed. The hydrofluoric acid generated from the HF gas selectively etches the deposition film 76 and the BPSG film 75, but generates a residue 41. The NH ₃ gas reacts with the residue 41 to generate a reaction product (NH ₄ F) that is easily sublimated, and the reaction product is easily sublimated by setting the atmospheric temperature in the chamber 22 to be slightly higher than room temperature. Is done. Accordingly, since the deposition film 76 and the BPSG film 75 can be removed in a dry environment, the gas process module 44 can be disposed in the substrate processing system 10. Thereby, the wafer W can be transferred to the gas process module 44 via the transfer module 11 after the etching of the single crystal silicon substrate 71. That is, the deposition film 76 and the BPSG film 75 can be removed without exposing the wafer W to the atmosphere after the etching of the single crystal silicon base material 71, the substrate processing process can be simplified, and the wafer W can be simplified. It is possible to eliminate the need to manage the exposure time to the atmosphere. As a result, it is possible to prevent the productivity of the semiconductor device from deteriorating.

  According to the above-described substrate processing method, since the gas process module 44 can be arranged in the substrate processing system, it is not necessary to install the gas process module 44 in another place, and the footprint can be reduced.

  Further, according to the above-described substrate processing method, the BPSG film 75 and the deposit film 76 can be selectively etched and the residue 41 can be removed only by the gas process module 44, so that the substrate processing system 10 can be downsized. Can do.

  Note that the selective etching of the BPSG film 75 and the deposition film 76, the generation of the reaction product from the residue 41, and the sublimation of the reaction product may be performed by different process modules.

In each of the above-described embodiments, the BPSG film 75 is used as the hard mask. However, the oxide film used as the hard mask is not limited to this, and any oxide film containing at least more impurities than the thermal oxide film 72 may be used. Specifically, it may be a TEOS (Tetra Ethyl Ortho Silicate) film or a BSG (Boron Silicate Glass) film. Further, the removed residue is not limited to H ₂ SiF ₆ . The present invention can be applied to the removal of the residue generated when the oxide film is removed with hydrofluoric acid.

  Another object of the present invention is to supply a computer with a storage medium storing software program codes for realizing the functions of the above-described embodiments, and the computer CPU reads out the program codes stored in the storage medium. It is also achieved by executing.

  In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the program code and the storage medium storing the program code constitute the present invention.

  Examples of the storage medium for supplying the program code include RAM, NV-RAM, floppy (registered trademark) disk, hard disk, magneto-optical disk, CD-ROM, CD-R, CD-RW, DVD (DVD). -ROM, DVD-RAM, DVD-RW, DVD + RW) and other optical disks, magnetic tapes, non-volatile memory cards, other ROMs, etc., as long as they can store the program code. Alternatively, the program code may be supplied to the computer by downloading from another computer or database (not shown) connected to the Internet, a commercial network, a local area network, or the like.

  Further, by executing the program code read by the computer, not only the functions of the above embodiments are realized, but also an OS (operating system) running on the CPU based on the instruction of the program code Includes a case where part or all of the actual processing is performed and the functions of the above-described embodiments are realized by the processing.

  Further, after the program code read from the storage medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. This includes a case where the CPU or the like provided in the board or the function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.

  The form of the program code may include an object code, a program code executed by an interpreter, script data supplied to the OS, and the like.

1 is a plan view showing a schematic configuration of a substrate processing system according to a first embodiment of the present invention. 2 is a cross-sectional view of the gas process module in FIG. 1, FIG. 2 (A) is a cross-sectional view taken along line II in FIG. 1, and FIG. 2 (B) is an enlarged view of a portion A in FIG. is there. It is process drawing which shows the substrate processing method which the substrate processing system of FIG. 1 performs. It is sectional drawing of the modification of the gas process module in FIG. It is sectional drawing of the gas process module in the substrate processing system which concerns on the 2nd Embodiment of this invention. It is process drawing which shows the substrate processing method which the substrate processing system which concerns on this Embodiment performs. It is sectional drawing which shows schematic structure of the wafer in which the deposition film which consists of SiOBr is formed in the surface of a hole.

Explanation of symbols

S processing space W wafer 10 substrate processing system 11 transfer module 12, 13, 14, 15 plasma process module 16, 42, 44 gas process module 17, thermal process module 24, 45 shower head 26 gas supply unit 41 residue 43 stage heater 46 Lower layer gas supply unit 47 Upper layer gas supply unit 71 Single crystal silicon substrate 72 Thermal oxide film 75 BPSG film 76 Deposition film

Claims (4)

A single crystal silicon substrate, a first oxide film formed by thermal oxidation treatment, and a second oxide film containing impurities, wherein the first and second oxide films are part of the single crystal silicon substrate; A substrate processing method for processing a substrate exposing a substrate in a chamber,
A plasma etching step of etching the exposed single crystal silicon substrate with a plasma of a halogen-based gas;
Removing water molecules from the chamber;
An HF gas supply step for supplying HF gas toward the substrate to transform the deposit film formed on the substrate in the second oxide film and the plasma etching step into a residue;
And a cleaning gas supply step of supplying a cleaning gas containing at least NH ₃ gas toward the substrate on which the first oxide film and the residue are present simultaneously. The plasma etching step, the HF between the gas supply step and the cleaning gas supply step, the substrate processing method according to claim 1, wherein the not the substrate is exposed to the atmosphere. A single crystal silicon substrate, a first oxide film formed by thermal oxidation treatment, and a second oxide film containing impurities, wherein the first and second oxide films are part of the single crystal silicon substrate; A substrate processing system for processing a substrate exposing a substrate in a chamber,
A plasma etching apparatus for etching the exposed single crystal silicon substrate with a halogen-based gas plasma;
While removing water molecules from the chamber, by supplying HF gas toward the front Stories substrate, thereby deterioration of the second oxide film and the deposition layer formed on the substrate by the plasma etching apparatus to the residue An HF gas supply device;
A substrate processing system, comprising: a cleaning gas supply device that supplies a cleaning gas containing at least NH ₃ gas toward the substrate on which the first oxide film and the residue are present simultaneously. The plasma etching apparatus, the HF is disposed between the gas supply device and the cleaning gas supply apparatus, and claim 3, said substrate characterized in that it comprises a substrate transfer device for transferring the substrate without exposing to the atmosphere The substrate processing system as described.

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