Small volume hydrogen sensor and method of processing same

Abstract

This invention relates to a small-volume hydrogen sensor and its fabrication method, comprising: a Wheatstone bridge, the Wheatstone bridge including: a catalytic component comprising two catalytic resistors with the same resistance, one of which is exposed to air and catalyzes hydrogen to generate heat within a preset temperature range; and a reference component providing a reference signal, the reference component comprising two doped reference resistors with the same resistance, the resistance of which is 100-1000 times that of the catalytic resistor. Its structure is compact, its manufacturing process is simple, and it saves on manufacturing costs.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and in particular to a small-volume hydrogen sensor and its fabrication method. Background Technology

[0002] Hydrogen fuel cells have been widely used in automobiles, nuclear power, and other fields. To avoid explosions caused by hydrogen leaks, the measurement of hydrogen leaks during hydrogen production, transportation, storage, and utilization has become a pressing issue that needs to be addressed. Among the many principles for detecting hydrogen leaks, MEMS catalytic combustion hydrogen sensors have broad development prospects due to their high sensitivity, small size, and low cost.

[0003] MEMS catalytic combustion hydrogen sensors convert changes in hydrogen concentration into changes in voltage output. To achieve high sensitivity, high linearity, and temperature compensation, designers typically fabricate a Wheatstone bridge with four metal resistors, referencing... Figure 1 As shown, R1 = R2 (hereinafter referred to as the catalytic resistor), and R1 is exposed to air to catalyze the hydrogen reaction and generate heat at high temperatures. The catalytic resistor is usually made of platinum or palladium, metals sensitive to hydrogen. R3 = R4 (hereinafter referred to as the metal reference resistor). The metal reference resistor can be made of the same metal as the catalytic resistor, or it can be other metals with low temperature coefficients. The resistance of the metal reference resistor should be 100-1000 times that of the catalytic resistor to generate as little Joule heat as possible.

[0004] The difference in resistance between the catalytic resistor and the metal reference resistor means that the surface area of ​​the metal reference resistor is hundreds to thousands of times larger than that of the catalytic resistor of the same material and cross-sectional area. If the space occupied by the line spacing is considered, this figure doubles, significantly increasing chip size, cost, and limiting its application in certain fields. There are generally three methods to design a low-surface-area metal reference resistor. First, when all four resistors are made of the same material and have the same thickness, a sufficiently narrow zigzag / serpentine coil can be fabricated within the process capability. Second, when all four resistors are made of the same material but have different thicknesses, a sufficiently narrow and thin zigzag / serpentine coil can be fabricated within the process capability. This method adds more processing steps than the first, but can further reduce the coil area ratio of the metal reference resistor. Third, a metal with higher resistivity and a lower temperature coefficient of resistivity can be used to fabricate the metal reference resistor, and a sufficiently narrow and thin zigzag / serpentine coil can be fabricated within the process capability. However, the precision of the manufacturing process limits the production of very thin and narrow lines, and the resistivity of commonly used metals is not high enough compared to that of platinum / palladium to allow the coil size to be reduced by a factor of two. Therefore, the size of the metal reference resistor remains the biggest factor limiting chip miniaturization. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the technical defect that the surface area of ​​the metal reference resistor in the hydrogen sensor is too large, which affects the miniaturization of the device.

[0006] To address the aforementioned technical problems, this invention provides a small-volume hydrogen sensor, comprising a Wheatstone bridge, wherein the Wheatstone bridge includes:

[0007] A catalytic assembly comprising two catalytic resistors of equal resistance, one of which is exposed to air, the catalytic resistor catalyzing hydrogen to produce heat within a preset temperature range;

[0008] A reference component that provides a reference signal, the reference component comprising two doped reference resistors with the same resistance value, the resistance value of the doped reference resistors being 100-1000 times that of the catalytic resistor.

[0009] Preferably, the doped reference resistor is fabricated by doping semiconductor material using ion implantation or diffusion processes.

[0010] Preferably, the semiconductor material is negative charge carrier silicon or positive charge carrier silicon.

[0011] Preferably, the catalytic resistor is made of platinum or palladium.

[0012] Preferably, the substrate of the Wheatstone bridge is a silicon substrate, and a first insulating groove is formed through the silicon substrate, with the catalytic resistor located above the first insulating groove.

[0013] Preferably, the two catalytic resistors are connected by metal leads, the two doped reference resistors are connected by metal leads, the catalytic resistors and the doped reference resistors are connected by metal leads, and a doped resistor connection region is connected between the doped reference resistor and its adjacent metal lead.

[0014] This invention discloses a method for fabricating a hydrogen sensor, comprising the following steps:

[0015] S1. A silicon oxide film is deposited on a silicon substrate by thermal oxidation or low-pressure vapor deposition, wherein the silicon oxide film is the first protective layer;

[0016] S2. A doped resistive connection region is formed on a silicon oxide film by photolithography and ion implantation.

[0017] S3. A doped reference resistor is formed on a silicon oxide film by photolithography and ion implantation, and the doped reference resistor is electrically connected to the doped resistor connection region.

[0018] S4. A pre-stressed silicon nitride film is formed on a silicon oxide film by plasma-enhanced vapor deposition, wherein the silicon nitride is a second protective layer.

[0019] S5. Photolithography and etching of the first and second protective layers directly above the doped resistor connection region, exposing the doped resistor connection region;

[0020] S6. Catalytic resistors, metal leads, and electrodes are fabricated by sputtering and stripping.

[0021] S7. A pre-stressed silicon oxide film, i.e., the third protective layer, is formed on a silicon nitride film by plasma-enhanced vapor deposition.

[0022] S8. Etch the third protective layer to expose the electrode and a catalytic resistor;

[0023] S9. The pads are fabricated by sputtering and peeling, and the pads are connected to the electrodes.

[0024] S10. An insulating groove is etched on the back using a dry etching process.

[0025] This invention discloses a method for fabricating a small-volume hydrogen sensor, comprising the following steps:

[0026] S1. A silicon oxide film, i.e., the first prefabricated layer, is deposited on a silicon substrate by thermal oxidation or low-pressure vapor deposition.

[0027] S2. The first prefabricated layer is formed by photolithography and etching, and a doped resistor connection region is formed by diffusion process;

[0028] S3. Remove the first prefabricated layer and deposit a silicon oxide film, i.e., the second prefabricated layer, on the silicon substrate by thermal oxidation or low-pressure vapor deposition.

[0029] S4. Photolithography and etching of the second prefabrication layer, and forming a doped reference resistor through diffusion process;

[0030] S5. Remove the second prefabricated layer and deposit a silicon oxide film, i.e., the first protective layer, on the silicon substrate by thermal oxidation or low-pressure vapor deposition.

[0031] S6. A pre-stressed silicon nitride film, i.e., the second protective layer, is formed by plasma-enhanced vapor deposition.

[0032] S7. The first and second protective layers are directly above the photolithographic and etched doped resistor connection region, exposing the doped resistor connection region;

[0033] S8. Catalytic resistors, metal leads, and electrodes are fabricated by sputtering and stripping.

[0034] S9. A pre-stressed silicon oxide film, i.e., the third protective layer, is formed by plasma-enhanced vapor deposition.

[0035] S10, Etch the third protective layer to expose the electrode and a catalytic resistor;

[0036] S11. Pads are fabricated by sputtering and stripping.

[0037] S12. An insulating groove is etched on the back of a silicon substrate using a dry etching process. The insulating groove is located on the back of the catalytic resistor.

[0038] This invention discloses a method for fabricating a small-volume hydrogen sensor, comprising the following steps:

[0039] S1: A silicon oxide film, i.e., the first protective layer, is formed on a silicon substrate by thermal oxidation or low-pressure vapor deposition.

[0040] S2: The doped resistive connection region is formed by photolithography and ion implantation process;

[0041] S3: A doped reference resistor is formed by photolithography and ion implantation.

[0042] S4: A pre-stressed silicon nitride film, i.e., the second protective layer, is formed by plasma-enhanced vapor deposition.

[0043] S5: A pre-stressed silicon oxide film, i.e., the third protective layer, is formed by plasma-enhanced vapor deposition.

[0044] S6: The first, second, and third protective layers directly above the photolithographic and etched doped resistor connection region expose the doped resistor connection region;

[0045] S7: Catalytic resistors, metal leads, and electrodes are fabricated by sputtering and stripping.

[0046] S8: A pre-stressed silicon nitride film, i.e., the fourth protective layer, is formed by plasma-enhanced vapor deposition.

[0047] S9: A pre-stressed silicon oxide film, i.e., the fifth protective layer, is formed by plasma-enhanced vapor deposition.

[0048] S10: Etch the fourth and fifth protective layers to expose the electrode and a catalytic resistor;

[0049] S11: Pads are created by sputtering and stripping.

[0050] S12: An insulating groove is etched on the back of a silicon substrate using a dry etching process. The insulating groove is located on the back of the catalytic resistor.

[0051] This invention discloses a method for fabricating a small-volume hydrogen sensor, comprising the following steps:

[0052] S1. A silicon oxide film, i.e., the first prefabricated layer, is deposited on a silicon substrate by thermal oxidation or low-pressure vapor deposition.

[0053] S2, photolithography and etching of the first prefabricated layer, and formation of doped resistor connection region through diffusion process;

[0054] S3. Remove the first prefabricated layer and deposit silicon oxide, i.e., the second prefabricated layer, on the silicon substrate by thermal oxidation or low-pressure vapor deposition.

[0055] S4. Photolithography and etching of the second prefabrication layer, and forming a doped reference resistor through diffusion process;

[0056] S5. Remove the second prefabricated layer and deposit a silicon oxide film, i.e., the first protective layer, on the silicon substrate by thermal oxidation or low-pressure vapor deposition.

[0057] S6. A pre-stressed silicon nitride film, i.e., the second protective layer, is formed by plasma-enhanced vapor deposition.

[0058] S7. A pre-stressed silicon oxide film, i.e., the third protective layer, is formed by plasma-enhanced vapor deposition.

[0059] S8. The first protective layer, the second protective layer, and the third protective layer are directly above the photolithographic and etched doped resistor connection region, exposing the doped resistor connection region;

[0060] S9. Catalytic resistors, metal leads, and electrodes are fabricated by sputtering and stripping.

[0061] S10. A pre-stressed silicon nitride film, i.e., the fourth protective layer, is formed by plasma-enhanced vapor deposition.

[0062] S11. A pre-stressed silicon oxide film, i.e., the fifth protective layer, is formed by plasma-enhanced vapor deposition.

[0063] S12, etch the fourth and fifth protective layers to expose the electrode and a catalytic resistor.

[0064] S13. Pads are fabricated by sputtering and stripping.

[0065] S14. An insulating groove is etched on the back of the silicon substrate using a dry etching process.

[0066] The technical solution of the present invention has the following advantages compared with the prior art:

[0067] 1. The working principle of this invention is to change the traditional method of making reference resistors from metal to doping, which can reduce the surface area by hundreds or even thousands of times while keeping the resistance value unchanged. Compared with existing reference resistors, its structure is more compact.

[0068] 2. In this invention, given the maturity of ion implantation / diffusion technology, obtaining a reference resistor through doping is a low-difficulty process, and the fabrication of a small-volume hydrogen sensor with a doped reference resistor is highly feasible and practical; in this invention, small-volume devices can save on process costs. Attached Figure Description

[0069] Figure 1 This is a schematic diagram of the Wheatstone bridge structure;

[0070] Figure 2 This is a front view of the small-volume hydrogen sensor of the present invention;

[0071] Figure 3 This is a top view of the small-volume hydrogen sensor of the present invention.

[0072] Explanation of reference numerals in the accompanying drawings: 10, substrate; 11, silicon oxide film; 12, silicon nitride film; 20, doped reference resistor; 21, doped resistor connection area; 22, metal lead; 30, electrode; 31, pad; 40, catalytic resistor. Detailed Implementation

[0073] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0074] Reference Figures 1-3 As shown, the present invention discloses a small-volume hydrogen sensor, including a Wheatstone bridge, the Wheatstone bridge including a catalytic component and a reference component.

[0075] The catalytic assembly includes two catalytic resistors 40 with the same resistance, one of which is exposed to air and catalyzes hydrogen to generate heat within a preset temperature range.

[0076] The reference component provides a reference signal and includes two doped reference resistors 20 with the same resistance value, which is 100-1000 times that of the catalytic resistor 40.

[0077] The working principle of this invention is to change the traditional method of making reference resistors from metal to doping, which can reduce the surface area by hundreds or even thousands of times while keeping the resistance value unchanged. Compared with existing reference resistors, its structure is more compact.

[0078] In this invention, given the maturity of ion implantation / diffusion technology, obtaining a reference resistor through doping is a low-difficulty process, and the fabrication of a small-volume hydrogen sensor with a doped reference resistor of 20 is highly feasible and practical. In this invention, small-volume devices can save on process costs.

[0079] Doped reference resistors are fabricated by doping semiconductor materials using ion implantation or diffusion processes.

[0080] The semiconductor material is either negative charge carrier silicon or positive charge carrier silicon.

[0081] The catalytic resistor 40 is made of platinum or palladium. The reference resistor can be made of the same metal as the catalytic resistor 40, or it can be made of other metals with low temperature coefficients. To reduce power consumption, the catalytic resistor 40 needs to generate Joule heat quickly and maintain its temperature by creating an insulating bath. The resistance of the metal reference resistor should be 100-1000 times that of the catalytic resistor 40 to generate as little Joule heat as possible and dissipate it as quickly as possible through the silicon substrate 10, avoiding excessive temperature that could lead to film stress mismatch and device failure.

[0082] The substrate 10 of the Wheatstone bridge is a silicon substrate 10, and a first insulating groove is formed through the silicon substrate 10. The catalytic resistor 40 is located on the upper side of the first insulating groove.

[0083] Two catalytic resistors 40 are connected by metal leads 22, two doped reference resistors 20 are connected by metal leads 22, the catalytic resistors 40 and the doped reference resistors 20 are connected by metal leads 22, and a doped resistor connection region 21 is connected between the doped reference resistors 20 and their adjacent metal leads 22.

[0084] This invention discloses a method for fabricating a hydrogen sensor, comprising the following steps:

[0085] S1. A silicon oxide film 11 is deposited on the silicon substrate 10 by thermal oxidation or low-pressure vapor deposition. The silicon oxide film 11 is the first protective layer.

[0086] S2. Photolithography is performed on the silicon oxide film 11 and a doped resistive connection region 21 is formed by ion implantation.

[0087] S3. A doped reference resistor 20 is formed on the silicon oxide film 11 by photolithography and ion implantation. The doped reference resistor 20 is electrically connected to the doped resistor connection region 21.

[0088] S4. A pre-stressed silicon nitride film 12 is formed on the silicon oxide film 11 by plasma-enhanced vapor deposition, with silicon nitride serving as the second protective layer.

[0089] S5. Photolithography and etching of the first and second protective layers directly above the doped resistor connection region 21 exposes the doped resistor connection region 21.

[0090] S6. The catalytic resistor 40, metal lead 22 and electrode 30 are fabricated by sputtering and stripping.

[0091] S7. A pre-stressed silicon oxide film 11, i.e., the third protective layer, is formed on the silicon nitride film 12 by plasma-enhanced vapor deposition.

[0092] S8. Etch the third protective layer to expose electrode 30 and a catalytic resistor 40;

[0093] S9. The pad 31 is fabricated by sputtering and stripping, and the pad 31 is connected to the electrode 30.

[0094] S10. An insulating groove is etched on the back using a dry etching process.

[0095] This invention discloses a method for fabricating a small-volume hydrogen sensor, comprising the following steps:

[0096] S1. A silicon oxide film 11, i.e. the first prefabricated layer, is deposited on the silicon substrate 10 by thermal oxidation or low-pressure vapor deposition.

[0097] S2. The first prefabricated layer is formed by photolithography and etching, and the doped resistor connection region 21 is formed by diffusion process;

[0098] S3. Remove the first prefabricated layer and deposit a silicon oxide film 11, i.e., the second prefabricated layer, on the silicon substrate 10 by thermal oxidation or low-pressure vapor deposition.

[0099] S4. Photolithography and etching of the second prefabrication layer, and forming a doped reference resistor 20 through a diffusion process;

[0100] S5. Remove the second prefabricated layer and deposit a silicon oxide film 11, i.e. the first protective layer, on the silicon substrate 10 by thermal oxidation or low-pressure vapor deposition.

[0101] S6. A prestressed silicon nitride film 12, i.e., the second protective layer, is formed by plasma-enhanced vapor deposition.

[0102] S7. The first and second protective layers are directly above the photolithography and etching doped resistor connection region 21, exposing the doped resistor connection region 21.

[0103] S8. The catalytic resistor 40, metal lead 22 and electrode 30 are fabricated by sputtering and stripping.

[0104] S9. A prestressed silicon oxide film 11, i.e., the third protective layer, is formed by plasma-enhanced vapor deposition.

[0105] S10, Etch the third protective layer to expose electrode 30 and a catalytic resistor 40;

[0106] S11. Pad 31 is fabricated by sputtering and stripping.

[0107] S12. An insulating groove is etched on the back of the silicon substrate 10 using a dry etching process. The insulating groove is located on the back of the catalytic resistor 40.

[0108] This invention discloses a method for fabricating a small-volume hydrogen sensor, comprising the following steps:

[0109] S1. A silicon oxide film 11, i.e., the first protective layer, is formed on a silicon substrate 10 by thermal oxidation or low-pressure vapor deposition.

[0110] S2. The doped resistive connection region 21 is formed by photolithography and ion implantation.

[0111] S3. A doped reference resistor 20 is formed by photolithography and ion implantation.

[0112] S4. A prestressed silicon nitride film 12, i.e., the second protective layer, is formed by plasma-enhanced vapor deposition.

[0113] S5. A prestressed silicon oxide film 11, i.e. the third protective layer, is formed by plasma-enhanced vapor deposition.

[0114] S6. The first protective layer, the second protective layer, and the third protective layer directly above the photolithographic and etched doped resistor connection region 21 expose the doped resistor connection region 21.

[0115] S7. The catalytic resistor 40, metal lead 22 and electrode 30 are fabricated by sputtering and stripping.

[0116] S8. A prestressed silicon nitride film 12, i.e. the fourth protective layer, is formed by plasma-enhanced vapor deposition.

[0117] S9. A prestressed silicon oxide film 11, i.e. the fifth protective layer, is formed by plasma-enhanced vapor deposition.

[0118] S10, Etch the fourth and fifth protective layers to expose electrode 30 and a catalytic resistor 40;

[0119] S11. Pad 31 is fabricated by sputtering and stripping.

[0120] S12. An insulating groove is etched on the back of the silicon substrate 10 using a dry etching process. The insulating groove is located on the back of the catalytic resistor 40.

[0121] This invention discloses a method for fabricating a small-volume hydrogen sensor, comprising the following steps:

[0122] S1. A silicon oxide film 11, i.e. the first prefabricated layer, is deposited on the silicon substrate 10 by thermal oxidation or low-pressure vapor deposition.

[0123] S2, photolithography and etching of the first prefabricated layer, and formation of doped resistor connection region 21 by diffusion process;

[0124] S3. Remove the first prefabricated layer and deposit silicon oxide, i.e., the second prefabricated layer, on the silicon substrate 10 by thermal oxidation or low-pressure vapor deposition.

[0125] S4. Photolithography and etching of the second prefabrication layer, and forming a doped reference resistor 20 through a diffusion process;

[0126] S5. Remove the second prefabricated layer and deposit a silicon oxide film 11, i.e. the first protective layer, on the silicon substrate 10 by thermal oxidation or low-pressure vapor deposition.

[0127] S6. A prestressed silicon nitride film 12, i.e., the second protective layer, is formed by plasma-enhanced vapor deposition.

[0128] S7. A prestressed silicon oxide film 11, i.e., the third protective layer, is formed by plasma-enhanced vapor deposition.

[0129] S8. The first protective layer, the second protective layer, and the third protective layer directly above the photolithographic and etched doped resistor connection region 21 expose the doped resistor connection region 21.

[0130] S9. The catalytic resistor 40, metal lead 22 and electrode 30 are fabricated by sputtering and stripping.

[0131] S10. A prestressed silicon nitride film 12, i.e. the fourth protective layer, is formed by plasma-enhanced vapor deposition.

[0132] S11. A prestressed silicon oxide film 11, i.e. the fifth protective layer, is formed by plasma-enhanced vapor deposition.

[0133] S12, etch the fourth and fifth protective layers to expose electrode 30 and a catalytic resistor 40.

[0134] S13. The pad 31 is fabricated by sputtering and stripping.

[0135] S14. An insulating groove is etched on the back of the silicon substrate 10 using a dry etching process.

[0136] In this invention, the reference resistor is fabricated using an ion implantation / diffusion process to perform low-concentration doping of N-type silicon (negative charge carrier silicon) or P-type silicon (positive charge carrier silicon) (hereinafter referred to as the doped reference resistor). The doped reference resistor achieves ohmic contact with titanium / platinum metal leads through a doped resistor connection region, thereby forming a Wheatstone bridge with the catalytic resistor. Taking the parameters of a certain foundry as an example, at 3e15 / cm 2Under ion implantation conditions of 70 keV, only 18 sheet resistances are needed to fabricate a 1 kΩ doped reference resistor. If the linewidth of the doped reference resistor is 5 μm, the line length is only 90 μm. In contrast, platinum (with a resistivity of 10.6 × 10⁻⁶) with the same linewidth and 200 nm thickness has the same resistance value. -6 The length of the metal reference resistor (Ω*cm) is 9.4mm, which is more than 100 times the length of the doped reference resistor. If the line spacing formed by the coil folding is taken into account, the surface area of ​​the metal reference resistor is more than 200 times that of the doped reference resistor.

[0137] The doped reference resistor fabricated in this invention can be made into resistors of different sizes by controlling the doping concentration. To achieve a doped reference resistor with a smaller surface area while maintaining the same resistance value, the implantation dose can be further reduced. Since the function of the reference resistor is to provide a differential signal of U / 2 to the Wheatstone bridge, and two reference resistors can eliminate environmental errors, changes in the implantation dose will not affect the output of the Wheatstone bridge or the performance of the sensor. According to simulation results, when the reference resistor value is 1kΩ, the temperature of the silicon substrate of the hydrogen sensor is below 100℃ under a 3.3V power supply. Therefore, there is no need to consider the failure of the pn junction of the doped reference resistor when the catalytic resistor operates at high temperatures (300-350℃).

[0138] The technical solution of the present invention will be further described and explained below with reference to specific embodiments.

[0139] In the first embodiment, a doped reference resistor is fabricated using an ion implantation process, and the device has a total of 3 layers: silicon oxide layer / silicon nitride layer / silicon oxide layer (hereinafter referred to as composite film layer); in the second embodiment, a doped reference resistor is fabricated using a diffusion process, and the device has a total of 3 composite film layers; in the third embodiment, a doped reference resistor is fabricated using an ion implantation process, and the device has a total of 5 composite film layers; and in the fourth embodiment, a doped reference resistor is fabricated using a diffusion process, and the device has a total of 5 composite film layers.

[0140] Example 1:

[0141] S1: A dense silicon oxide film with a thickness of 30-1500 nm is deposited on a silicon substrate by thermal oxidation / LPCVD (low-pressure vapor deposition), i.e., protective layer 1;

[0142] S2: The doped resistive connection region is formed by photolithography and ion implantation process;

[0143] S3: A doped reference resistor is formed by photolithography and ion implantation.

[0144] S4: A pre-stressed silicon nitride film, i.e., protective layer 2, with a thickness of 30-1000 nm, is formed by PECVD (plasma-enhanced vapor deposition).

[0145] S5: Photolithography and etching of protective layer 1 and protective layer 2 directly above the doped resistor connection area, exposing the doped resistor connection area;

[0146] S6: 100-300 nm thick titanium / platinum catalytic resistors, titanium / platinum metal leads and titanium / platinum electrodes are fabricated by sputtering and stripping.

[0147] S7: A pre-stressed silicon oxide film, i.e., protective layer 3, with a thickness of 30-1000 nm, is formed by PECVD (plasma-enhanced vapor deposition).

[0148] S8: Etching protective layer 3 exposes the titanium / platinum catalytic resistor and 4 titanium / platinum electrodes in the upper left corner;

[0149] S9: Titanium / gold pads with a thickness of 100-300nm are fabricated by sputtering and stripping.

[0150] S10: Insulation grooves are etched on the back using a dry etching process.

[0151] Example 2:

[0152] S1: A dense silicon oxide film with a thickness of 500-850 nm is deposited on a silicon substrate by thermal oxidation / LPCVD (low-pressure vapor deposition), i.e., protective layer 1.1;

[0153] S2: Photolithography and etching protective layer 1.1, and a doped resistor connection region is formed through diffusion process;

[0154] S3: Remove the protective layer 1.1 and deposit a dense silicon oxide film with a thickness of 500-850 nm on the silicon substrate by thermal oxidation / LPCVD (low-pressure vapor deposition), i.e., protective layer 1.2;

[0155] S4: Photolithography and etching protective layer 1.2, and a doped reference resistor is formed through diffusion process;

[0156] S5: Remove the protective layer 1.2 and deposit a dense silicon oxide film with a thickness of 30-1500 nm on the silicon substrate by thermal oxidation / LPCVD (low-pressure vapor deposition), i.e., protective layer 1;

[0157] S6: A pre-stressed silicon nitride film, i.e., protective layer 2, with a thickness of 30-1000 nm, is formed by PECVD (plasma-enhanced vapor deposition).

[0158] S7: Photolithography and etching of protective layer 1 and protective layer 2 directly above the doped resistor connection area, exposing the doped resistor connection area;

[0159] S8: 100-300 nm thick titanium / platinum catalytic resistors, titanium / platinum metal leads and titanium / platinum electrodes are fabricated by sputtering and stripping.

[0160] S9: A pre-stressed silicon oxide film, i.e., protective layer 3, with a thickness of 30-1000 nm, is formed by PECVD (plasma-enhanced vapor deposition).

[0161] S10: Etching protective layer 3 exposes the titanium / platinum catalytic resistor and 4 titanium / platinum electrodes in the upper left corner;

[0162] S11: Titanium / gold pads with a thickness of 100-300nm are fabricated by sputtering and stripping.

[0163] S12: An insulating groove is etched on the back using a dry etching process.

[0164] Example 3:

[0165] S1: A dense silicon oxide film with a thickness of 30-1500 nm is formed on a silicon substrate by thermal oxidation / LPCVD (low-pressure vapor deposition), i.e., protective layer 1;

[0166] S2: The doped resistive connection region is formed by photolithography and ion implantation process;

[0167] S3: A doped reference resistor is formed by photolithography and ion implantation.

[0168] S4: A pre-stressed silicon nitride film, i.e., protective layer 2, with a thickness of 30-1000 nm, is formed by PECVD (plasma-enhanced vapor deposition).

[0169] S5: A pre-stressed silicon oxide film, i.e., protective layer 3, with a thickness of 30-1000 nm, is formed by PECVD (plasma-enhanced vapor deposition).

[0170] S6: Photolithography and etching of protective layers 1, 2 and 3 directly above the doped resistor connection area, exposing the doped resistor connection area;

[0171] S7: 100-300 nm thick titanium / platinum catalytic resistors, titanium / platinum metal leads and titanium / platinum electrodes are fabricated by sputtering and stripping.

[0172] S8: A pre-stressed silicon nitride film, i.e., protective layer 4, with a thickness of 30-1000 nm, is formed by PECVD (plasma-enhanced vapor deposition).

[0173] S9: A pre-stressed silicon oxide film, i.e., protective layer 5, with a thickness of 30-1000 nm, is formed by PECVD (plasma-enhanced vapor deposition).

[0174] S10: Etch protective layers 4 and 5 to expose the titanium / platinum catalytic resistor and 4 titanium / platinum electrodes in the upper left corner;

[0175] S11: Titanium / gold pads with a thickness of 100-300nm are fabricated by sputtering and stripping.

[0176] S12: An insulating groove is etched on the back using a dry etching process.

[0177] Example 4:

[0178] S1: A dense silicon oxide film with a thickness of 500-850 nm is deposited on a silicon substrate by thermal oxidation / LPCVD (low-pressure vapor deposition), i.e., protective layer 1.1;

[0179] S2: Photolithography and etching protective layer 1.1, and a doped resistor connection region is formed through diffusion process;

[0180] S3: Remove the protective layer 1.1 and deposit a dense silicon oxide layer with a thickness of 500-850 nm on the silicon substrate by thermal oxidation / LPCVD (low-pressure vapor deposition), i.e., protective layer 1.2;

[0181] S4: Photolithography and etching protective layer 1.2, and a doped reference resistor is formed through diffusion process;

[0182] S5: Remove the protective layer 1.2 and deposit a dense silicon oxide film with a thickness of 500-850 nm on the silicon substrate by thermal oxidation / LPCVD (low-pressure vapor deposition), i.e., protective layer 1;

[0183] S6: A pre-stressed silicon nitride film, i.e., protective layer 2, with a thickness of 30-1000 nm, is formed by PECVD (plasma-enhanced vapor deposition).

[0184] S7: A pre-stressed silicon oxide film, i.e., protective layer 3, with a thickness of 30-1000 nm, is formed by PECVD (plasma-enhanced vapor deposition).

[0185] S8: Photolithography and etching of protective layers 1, 2 and 3 directly above the doped resistor connection area, exposing the doped resistor connection area;

[0186] S9: 100-300 nm thick titanium / platinum catalytic resistors, titanium / platinum metal leads and titanium / platinum electrodes are fabricated by sputtering and stripping.

[0187] S10: A pre-stressed silicon nitride film, i.e., protective layer 4, is formed by PECVD (plasma-enhanced vapor deposition), with a thickness of 30-1000 nm.

[0188] S11: A pre-stressed silicon oxide film, i.e., protective layer 5, with a thickness of 30-1000 nm, is formed by PECVD (plasma-enhanced vapor deposition).

[0189] S12: Etch protective layers 4 and 5 to expose the titanium / platinum catalytic resistor and 4 titanium / platinum electrodes in the upper left corner;

[0190] S13: 100-300nm thick titanium / gold pads are fabricated by sputtering and stripping.

[0191] S14: An insulating groove is etched on the back using a dry etching process.

[0192] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0193] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0194] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0195] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0196] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A small-volume hydrogen sensor, characterized in that, Includes a Wheatstone bridge, the Wheatstone bridge comprising: A catalytic assembly comprising two catalytic resistors of the same resistance, one of which is exposed to air and catalyzes the generation of heat from hydrogen within a preset temperature range; A reference component that provides a reference signal includes two doped reference resistors with the same resistance value, the resistance of which is 100-1000 times that of the catalytic resistor; The doped reference resistor is fabricated by doping semiconductor material using ion implantation or diffusion processes, thereby reducing the surface area while maintaining the same resistance value. The semiconductor material is either negatively charged carrier silicon or positively charged carrier silicon; The substrate of the Wheatstone bridge is a silicon substrate, and an insulating groove is formed through the silicon substrate. The catalytic resistor is located on the upper side of the insulating groove.

2. The small-volume hydrogen sensor according to claim 1, characterized in that, The catalytic resistor is made of platinum or palladium.

3. The small-volume hydrogen sensor according to claim 1, characterized in that, The two catalytic resistors are connected by metal leads, the two doped reference resistors are connected by metal leads, the catalytic resistors and the doped reference resistors are connected by metal leads, and a doped resistor connection region is connected between the doped reference resistor and its adjacent metal lead.

4. A method of processing a small volume hydrogen sensor as claimed in any one of claims 1 to 3, characterized in that, Includes the following steps: S1. A silicon oxide film is deposited on a silicon substrate by thermal oxidation or low-pressure vapor deposition, wherein the silicon oxide film is the first protective layer; S2. A doped resistive connection region is formed on a silicon oxide film by photolithography and ion implantation. S3. A doped reference resistor is formed on a silicon oxide film by photolithography and ion implantation, and the doped reference resistor is electrically connected to the doped resistor connection region. S4. A pre-stressed silicon nitride film is formed on a silicon oxide film by plasma-enhanced vapor deposition, wherein the silicon nitride is a second protective layer. S5. Photolithography and etching of the first and second protective layers directly above the doped resistor connection region, exposing the doped resistor connection region; S6. Catalytic resistors, metal leads, and electrodes are fabricated by sputtering and stripping. S7. A pre-stressed silicon oxide film, i.e., the third protective layer, is formed on a silicon nitride film by plasma-enhanced vapor deposition. S8. Etch the third protective layer to expose the electrode and a catalytic resistor; S9. The pads are fabricated by sputtering and peeling, and the pads are connected to the electrodes. S10. An insulating groove is etched on the back of the silicon substrate using a dry etching process.

5. A method of processing a small volume hydrogen sensor as claimed in any one of claims 1 to 3, characterized in that, Includes the following steps: S1. A silicon oxide film, i.e., the first prefabricated layer, is deposited on a silicon substrate by thermal oxidation or low-pressure vapor deposition. S2, photolithography and etching of the first prefabricated layer, and formation of doped resistor connection region through diffusion process; S3. Remove the first prefabricated layer and deposit a silicon oxide film, i.e., the second prefabricated layer, on the silicon substrate by thermal oxidation or low-pressure vapor deposition. S4. Photolithography and etching of the second prefabrication layer, and forming a doped reference resistor through diffusion process; S5. Remove the second prefabricated layer and deposit a silicon oxide film, i.e., the first protective layer, on the silicon substrate by thermal oxidation or low-pressure vapor deposition. S6. A pre-stressed silicon nitride film, i.e., the second protective layer, is formed by plasma-enhanced vapor deposition. S7. The first and second protective layers are directly above the photolithographic and etched doped resistor connection region, exposing the doped resistor connection region; S8. Catalytic resistors, metal leads, and electrodes are fabricated by sputtering and stripping. S9. A pre-stressed silicon oxide film, i.e., the third protective layer, is formed by plasma-enhanced vapor deposition. S10, Etch the third protective layer to expose the electrode and a catalytic resistor; S11. Pads are fabricated by sputtering and stripping. S12. An insulating groove is etched on the back of a silicon substrate using a dry etching process. The insulating groove is located on the back of the catalytic resistor.

6. A method of processing a small volume hydrogen sensor as claimed in any one of claims 1 to 3, characterized in that, Includes the following steps: S1: A silicon oxide film, i.e., the first protective layer, is formed on a silicon substrate by thermal oxidation or low-pressure vapor deposition. S2: The doped resistive connection region is formed by photolithography and ion implantation process; S3: A doped reference resistor is formed by photolithography and ion implantation. S4: A pre-stressed silicon nitride film, i.e., the second protective layer, is formed by plasma-enhanced vapor deposition. S5: A pre-stressed silicon oxide film, i.e., the third protective layer, is formed by plasma-enhanced vapor deposition. S6: The first, second, and third protective layers directly above the photolithographic and etched doped resistor connection region expose the doped resistor connection region; S7: Catalytic resistors, metal leads, and electrodes are fabricated by sputtering and stripping. S8: A pre-stressed silicon nitride film, i.e., the fourth protective layer, is formed by plasma-enhanced vapor deposition. S9: A pre-stressed silicon oxide film, i.e., the fifth protective layer, is formed by plasma-enhanced vapor deposition. S10: Etch the fourth and fifth protective layers to expose the electrode and a catalytic resistor; S11: Pads are fabricated using sputtering and stripping methods; S12: An insulating groove is etched on the back of a silicon substrate using a dry etching process. The insulating groove is located on the back of the catalytic resistor.

7. A method of processing a small volume hydrogen sensor as claimed in any one of claims 1 to 3, characterized in that, Includes the following steps: S1. A silicon oxide film, i.e., the first prefabricated layer, is deposited on a silicon substrate by thermal oxidation or low-pressure vapor deposition. S2, photolithography and etching of the first prefabricated layer, and formation of doped resistor connection region through diffusion process; S3. Remove the first prefabricated layer and deposit silicon oxide, i.e., the second prefabricated layer, on the silicon substrate by thermal oxidation or low-pressure vapor deposition. S4. Photolithography and etching of the second prefabrication layer, and forming a doped reference resistor through diffusion process; S5. Remove the second prefabricated layer and deposit a silicon oxide film, i.e., the first protective layer, on the silicon substrate by thermal oxidation or low-pressure vapor deposition. S6. A pre-stressed silicon nitride film, i.e., the second protective layer, is formed by plasma-enhanced vapor deposition. S7. A pre-stressed silicon oxide film, i.e., the third protective layer, is formed by plasma-enhanced vapor deposition. S8. The first protective layer, the second protective layer, and the third protective layer directly above the photolithographic and etched doped resistor connection region expose the doped resistor connection region. S9. Catalytic resistors, metal leads, and electrodes are fabricated by sputtering and stripping. S10. A pre-stressed silicon nitride film, i.e., the fourth protective layer, is formed by plasma-enhanced vapor deposition. S11. A pre-stressed silicon oxide film, i.e., the fifth protective layer, is formed by plasma-enhanced vapor deposition. S12, Etch the fourth and fifth protective layers to expose the electrode and a catalytic resistor; S13. Pads are fabricated by sputtering and stripping. S14, etching the adiabatic groove on the back of the silicon substrate by a dry etching process.

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