JP5663120B2 - Pressure detection device - Google Patents

Description

  The present invention relates to a pressure detection device that detects the pressure of a gas.

  A semiconductor manufacturing apparatus processes a wafer in a predetermined reduced pressure atmosphere in a processing container. Therefore, a pressure detection device is used to detect the pressure in the processing container of the semiconductor manufacturing apparatus.

  A highly corrosive gas may be present in a processing container of a semiconductor manufacturing apparatus, for example, in the course of wafer processing. Therefore, it is desired that the pressure detection device has high corrosion resistance.

  As a conventional pressure detection device, a capacitance type vacuum gauge is known which has improved corrosion resistance by covering a gas contact surface of a silicon diaphragm with any one of aluminum oxide, zirconium oxide and titanium oxide as a protective film. (For example, refer to Patent Document 1).

JP 2002-214059 A

  The inventor of the present application, because the conventional pressure detection device has a metal oxide protective film on the silicon diaphragm, the displacement of the silicon diaphragm is hindered by the protective film, narrowing the pressure detection range and reducing accuracy. I found out.

  Therefore, an object of the present invention is to provide a pressure detection device that can improve the pressure detection performance as compared with the conventional one while having corrosion resistance.

  The pressure detection device of the present invention includes a capacitance type pressure sensor module that detects a pressure of the gas by forming a gas contact surface in contact with the gas, and the pressure sensor module is disposed on the gas contact surface. It is characterized by comprising an amorphous metal protective film and a silicon diaphragm that is covered with the protective film and is displaced in accordance with the pressure of the gas.

  With this configuration, the pressure detection device of the present invention has corrosion resistance because the protective film is formed of amorphous metal having corrosion resistance. Moreover, since the protective film is formed by the amorphous metal whose elasticity is higher than that of the metal oxide in the pressure detection device of the present invention, the elasticity of the protective film is improved as compared with the conventional case. Therefore, in the pressure detection device of the present invention, the displacement of the silicon diaphragm is not easily disturbed by the protective film, and the pressure detection performance can be improved.

  The amorphous metal of the pressure detection device of the present invention may be a nickel-based amorphous metal.

  With this configuration, the pressure detection device of the present invention can further improve the corrosion resistance because the protective film is formed of an amorphous metal mainly composed of nickel having excellent corrosion resistance.

  In addition, the pressure detection device of the present invention may include an adhesion layer between the silicon diaphragm and the protective film.

  With this configuration, the pressure detection device of the present invention can improve the adhesion between the silicon diaphragm and the protective film by the adhesion layer.

  The pressure detection device of the present invention can improve the pressure detection performance as compared with the conventional one while having corrosion resistance.

It is sectional drawing of the pressure detection apparatus which concerns on one embodiment of this invention. It is a bottom view of the pressure sensor module of the pressure detection apparatus shown in FIG. It is a figure which shows the relationship between the displacement amount of the silicon diaphragm shown in FIG. 1 with respect to the pressure change of gas, and the film thickness of the protective film of the ternary system nickel base amorphous metal of Ni60-Nb30-Ti10. It is a figure which shows the relationship between the displacement amount of the silicon diaphragm shown in FIG. 1 with respect to the pressure change of gas, and the film thickness of a protective film when a protective film is formed with aluminum oxide. FIG. 2 is a diagram showing a list of composition ratios of Ni—Nb—Ti ternary nickel-based amorphous metals suitable for the protective film shown in FIG. 1. FIG. 6 is a list of composition ratios of Ni—Nb—Ti ternary nickel-based amorphous metals suitable for the protective film shown in FIG. 1, and a list different from the list shown in FIG. 5. It is a figure which shows distribution of the nickel base amorphous metal of the ternary system of Ni-Nb-Ti represented to the list | wrist shown in FIG. 5 and FIG.

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

  First, the configuration of the pressure detection device according to the present embodiment will be described.

  FIG. 1 is a cross-sectional view of a pressure detection device 10 according to the present embodiment.

  As shown in FIG. 1, a pressure detection device 10 includes a capacitance type pressure sensor module 20 that detects a gas pressure, electrode pins 30 a and 30 b that take out an output of the pressure sensor module 20, and a pressure sensor module. 20, a support member 31 for supporting 20, an O-ring 32 installed on the support member 31 to prevent gas leakage between the pressure sensor module 20 and the support member 31, and a pressure by being fixed to the support member 31. A pressing member 33 that presses the sensor module 20 against the O-ring 32, a screw 34 that fixes the pressing member 33 to the support member 31, and the pressure sensor module 20, the O-ring 32, the pressing member 33, and And a cover 35 covering the screws 34.

  In the pressure sensor module 20, a gas contact surface 20 a in contact with gas is formed in a portion surrounded by the O-ring 32.

  The support member 31 has a gas introduction hole 31a into which gas is introduced. The support member 31 is made of SUS316L and has corrosion resistance.

  The O-ring 32 is formed of a rubber having corrosion resistance.

  The presser member 33 has a protrusion 33 a that contacts the pressure sensor module 20.

  FIG. 2 is a bottom view of the pressure sensor module 20 of the pressure detection device 10.

  As shown in FIGS. 1 and 2, the pressure sensor module 20 includes a plate-like base glass 21 having a truncated cone-shaped hole 21 a formed at the center, and a silicon substrate 22 fixed to one surface of the base glass 21. A glass lid 23 that is fixed to the silicon substrate 22 on the opposite side of the base glass 21 and forms the vacuum chamber 20b together with the silicon substrate 22, and a glass lid at a position facing the silicon substrate 22 in the vacuum chamber 20b. 23, a silicon electrode plate 24 fixed on 23, a protective film 25 for protecting the base glass 21 and the silicon substrate 22, and an adhesion layer (intermediate layer) 26 for improving the adhesion between the silicon substrate 22 and the protective film 25. And.

  The base glass 21 is made of Pyrex (registered trademark) glass.

  In the silicon substrate 22, a silicon diaphragm 22 a that can be displaced according to pressure is formed in a portion corresponding to the hole 21 a of the base glass 21.

  The glass lid 23 is made of Pyrex glass. The glass lid 23 electrically connects the silicon substrate 22 and the electrode pin 30a through the electrode pin 30a, and electrically connects the silicon electrode plate 24 and the electrode pin 30a through the electrode pin 30b. doing.

  The protective film 25 covers the surface of the base glass 21 opposite to the surface on the silicon substrate 22 side and the portion of the silicon substrate 22 surrounded by the hole 21 a of the base glass 21. The protective film 25 is made of amorphous metal. The amorphous metal forming the protective film 25 is preferably a nickel-based amorphous metal such as a Ni—Nb—Ti ternary amorphous metal, but may be an amorphous metal other than the nickel-based amorphous metal. Further, the amorphous metal forming the protective film 25 may be an amorphous metal such as Ru-Zr-Si ternary metallic glass.

  The adhesion layer 26 is formed of a Cr film.

  The pressure detection device 10 detects the displacement of the silicon diaphragm 22a due to the difference between the degree of vacuum (pressure) in the vacuum chamber 20b and the degree of vacuum (pressure) in the gas introduction hole 31a, the silicon diaphragm 22a, the silicon electrode plate 24, This is a device that measures the pressure of the gas in the gas introduction hole 31a by detecting the change in the capacitance between the two.

  Next, a manufacturing method of the pressure sensor module 20 will be described.

  First, the silicon diaphragm 22a is formed on the silicon substrate 22 by anisotropic etching while maintaining the tension. Further, the silicon electrode plate 24 is bonded to the glass lid 23.

  Next, the silicon substrate 22 is vacuum bonded to the glass lid 23 and the base glass 21.

  Finally, amorphous metal is formed as a protective film 25 on the surface of the base glass 21 opposite to the surface on the silicon substrate 22 side and the portion of the silicon substrate 22 surrounded by the holes 21a of the base glass 21. Covered.

  Next, a method for forming the protective film 25 will be described with a specific example.

First, an RF sputtering device (high frequency sputtering device) is formed on the surface of the base glass 21 opposite to the surface on the silicon substrate 22 side and the portion of the silicon substrate 22 surrounded by the hole 21a of the base glass 21. The adhesion layer 26 is formed by coating the Cr film. As sputtering conditions, the target is a Cr target, the ultimate vacuum is 1 × 10 ⁻⁴ Pa (pascal) or less, the substrate temperature is 15 ° C., the reaction gas is argon gas, and the pressure is 0.4 Pa. To 1.0 Pa, and the input power is 300 W.

Finally, the protective film 25 is coated on the adhesion layer 26 by an RF sputtering apparatus. The protective film 25 is a ternary nickel-based amorphous metal of Ni60-Nb30-Ti10. As sputtering conditions, the target is a nickel-based amorphous metal (Ni60-Nb30-Ti10) target, the ultimate vacuum is 1 × 10 ⁻⁴ Pa or less, the substrate temperature is 15 ° C., and the reaction gas is argon gas. Yes, the pressure is 0.4 Pa to 1.0 Pa, and the input power is 400 W.

  Next, the property of the pressure sensor module 20 provided with the protective film 25 of the ternary nickel-based amorphous metal of Ni60-Nb30-Ti10 formed by the above-described forming method will be described.

  First, the adhesion of the protective film 25 will be described.

  A tape test of the protective film 25 was performed on a plurality of pressure sensor modules 20 having different thicknesses of the protective film 25 and the adhesion layer 26. Here, the film thickness of the protective film 25 was between 0.5 and 2.5 μm, and the film thickness of the adhesion layer 26 was between 0.1 and 0.5 μm. As a result of the tape test, problems such as peeling were not confirmed in all film thicknesses. Therefore, it was confirmed that the protective film 25 has high adhesion.

  Next, the corrosion resistance of the protective film 25 will be described.

  Although the pressure sensor module 20 was exposed to the cleaning gas used in the semiconductor process for about two weeks, the displacement of the silicon diaphragm 22a with respect to the gas pressure did not change before and after the exposure. Therefore, it was confirmed that the protective film 25 has high corrosion resistance.

  Next, the displacement of the silicon diaphragm 22a will be described.

  FIG. 3 is a diagram showing the relationship between the displacement amount of the silicon diaphragm 22a with respect to the gas pressure change and the film thickness of the protective film 25 of the ternary nickel-based amorphous metal of Ni60-Nb30-Ti10. In FIG. 3, a cross indicates a displacement amount of the silicon diaphragm 22 a before the protective film 25 is formed, which is a displacement amount with respect to a gas of 1.33 kPa.

  In FIG. 3, X is a film thickness (unit: μm) of the protective film 25, and Y is a displacement amount (unit: μm) of the silicon diaphragm 22a. The hatched range shown in FIG. 3 indicates the displacement of the silicon diaphragm 22a with respect to the pressure change of 0 kPa to 1.33 kPa of gas when the thickness of the protective film 25 is 0.5 μm to 2.5 μm. Within the hatched area shown in FIG. 3, it was confirmed that the silicon diaphragm 22a was not bent and the tension of the silicon diaphragm 22a could be maintained.

FIG. 4 is a diagram showing the relationship between the amount of displacement of the silicon diaphragm 22a with respect to a change in gas pressure and the film thickness of the protective film 25 when the protective film 25 is formed of aluminum oxide (Al ₂ O ₃ ). . In FIG. 4, a cross indicates a displacement amount of the silicon diaphragm 22 a before the protective film 25 is formed, and indicates a displacement amount with respect to a gas of 1.33 kPa.

The pressure sensor module that acquired the data that is the basis of the diagram shown in FIG. 4 has the same configuration as the pressure sensor module 20 except for the protective film 25, including the material and size. The protective film 25 made of aluminum oxide is also coated by an RF sputtering apparatus, similarly to the protective film 25 made of Ni60-Nb30-Ti10 ternary nickel-based amorphous metal. As sputtering conditions, the target is an Al ₂ O ₃ target (alumina target), the ultimate vacuum is 1 × 10 ⁻⁴ Pa or less, the substrate temperature is 200 ° C., and the reaction gas is a mixed gas of argon and oxygen. The pressure is 0.4 Pa to 0.7 Pa, and the input power is 300 W.

  In FIG. 4, X is a film thickness (unit: μm) of the protective film 25, and Y is a displacement amount (unit: μm) of the silicon diaphragm 22a. 4 indicates the amount of displacement of the silicon diaphragm 22a with respect to the pressure change of gas from 0 kPa to 1.33 kPa when the thickness of the protective film 25 is about 0.2 μm to 1.0 μm. . Within the hatched area shown in FIG. 4, it was confirmed that the silicon diaphragm 22a did not bend and the tension of the silicon diaphragm 22a could be maintained.

As shown in FIGS. 3 and 4, the pressure sensor module 20 including the Ni60-Nb30-Ti10 ternary nickel-based amorphous metal protective film 25 is composed of a protective film of Al ₂ O ₃ that is a metal oxide. Compared with the pressure sensor module having 25, it was confirmed that the pressure detection performance was high.

  Note that the thickness of the protective film 25 shown in FIG. 4 is concentrated in a range thinner than the thickness of the protective film 25 shown in FIG. This is because of the difference in workability and productivity between the protective film 25 made of metal oxide and the protective film 25 made of amorphous metal.

  <Workability> When the protective film 25 of metal oxide such as aluminum oxide is formed thick, warping and cracking are likely to occur due to internal stress. That is, the protective film 25 of amorphous metal such as Ni60-Nb30-Ti10 ternary nickel-based amorphous metal has better workability than the protective film 25 of metal oxide such as aluminum oxide.

  <Productivity> The protective film 25 of a metal oxide such as aluminum oxide has a significantly slower film forming speed than the protective film 25 of an amorphous metal such as a ternary nickel-based amorphous metal of Ni60-Nb30-Ti10. . That is, the protective film 25 of amorphous metal such as Ni60-Nb30-Ti10 ternary nickel-based amorphous metal has higher productivity than the protective film 25 of metal oxide such as aluminum oxide. For example, when sputtering is performed under the same sputtering conditions as when the deposition speed of the protective film 25 of aluminum oxide is 0.028 μm / min, the ternary nickel-based amorphous metal of Ni60-Nb30-Ti10 is used. The deposition speed of the protective film 25 is 0.650 μm / min, which is 20 times or more the deposition speed of the protective film 25 made of aluminum oxide.

  As described above, the pressure detection device 10 has corrosion resistance because the protective film 25 is formed of an amorphous metal having corrosion resistance.

  Moreover, since the protective film 25 is formed of the amorphous metal whose elasticity is higher than that of the metal oxide in the pressure detection device 10, the elasticity of the protective film 25 is improved as compared with the related art. Therefore, the pressure detection device 10 is more difficult to prevent the displacement of the silicon diaphragm 22a from being conventionally prevented by the protective film 25, and can improve the pressure detection performance.

  Further, when the pressure detection device 10 is a nickel-based amorphous metal, the corrosion resistance can be further improved because the protective film 25 is formed of an amorphous metal mainly composed of nickel having excellent corrosion resistance.

  Further, when the pressure detection device 10 includes the adhesion layer 26 between the silicon diaphragm 22 a and the protective film 25, the adhesion between the silicon diaphragm 22 a and the protective film 25 can be improved by the adhesion layer 26. it can.

In this embodiment, the ternary nickel-base amorphous metal of Ni60-Nb30-Ti10 has been described as an example of the Ni-Nb-Ti ternary nickel-base amorphous metal. However, the present invention is not limited to this. It is not a thing. The inventor of the present application formed a Ni—Nb—Ti ternary nickel-based amorphous metal having a composition ratio of about 500 on a ceramic plate by combinatorial sputtering, and formed the ceramic plate with a semiconductor manufacturing cleaning gas. A test was conducted to find the composition ratio of Ni-Nb-Ti ternary nickel-based amorphous metal that did not corrode in any gas by exposure to ClF ₃ , COF ₂ , and NF ₃ for about 290 hours. It was. FIG. 5 and FIG. 6 show the results of the test described above, the Ni—Nb—Ti ternary nickel-based amorphous metal that did not corrode in any of ClF ₃ , COF ₂ , and NF ₃ , that is, the protective film 25. It is a figure which shows the list of the composition ratios of the Ni-Nb-Ti ternary nickel-base amorphous metal suitable for the above. FIG. 7 is a diagram showing a distribution of Ni—Nb—Ti ternary nickel-based amorphous metals represented in the lists shown in FIGS. 5 and 6. As a result of the above-described test, Ni47-Nb46-Ti07, Ni49-Nb35-Ti16, Ni56-Nb33-Ti11, Ni60-Nb30-Ti10, Ni54-Nb30-Ti16, Ni is 42 to 65%, and Nb is 25 to 25%. A Ni-Nb-Ti ternary nickel-based amorphous metal with 51% and Ti of 2-21% was found to be optimal. In particular, a ternary nickel-based amorphous metal of Ni56-Nb33-Ti11 was ideal.

DESCRIPTION OF SYMBOLS 10 Pressure detection apparatus 20 Pressure sensor module 20a Gas contact surface 22a Silicon diaphragm 25 Protective film 26 Adhesion layer

Claims (3)

Gas is formed gas contact surface in contact includes a pressure sensor module for detecting the pressure of said gas,
The pressure sensor module, the pressure detection device, characterized in that it comprises a protective layer of amorphous metal ternary subjected to the gas-contacting surface.   The pressure detection device according to claim 1, wherein the amorphous metal is a nickel-based amorphous metal. The pressure sensor module includes a silicon diaphragm that is covered with the protective film and is displaced according to the pressure of the gas,
The pressure sensor module, and the silicon diaphragm, said silicon diaphragm the adhesion layer for enhancing the adhesion between the protective film according to claim 1, or claims, characterized in that it comprises between said protective film Item 3. The pressure detection device according to Item 2.

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