Method for manufacturing and separating pressure sensor
Through the bonding of silicon substrates and silicon wafers and chemical mechanical thinning technology, combined with photolithography and wet etching, the hollow structure fracture problem of high-pressure ultra-thin pressure sensors is solved, and low-cost, high-response sensitivity sensor production is achieved , meet the needs of large-scale mass production.
Patent Information
- Application Number
- CN202411343432.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-25
- Publication Date
- 2024-12-27
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The hollow structure design of existing high-pressure ultra-thin pressure sensors is easy to break, not easy to pick up, and has high production costs, making it difficult to meet the needs of large-scale mass production.
The silicon substrate and silicon wafer are bonded under the protection of silicon oxide, and the top silicon layer is formed by chemical mechanical thinning, and the piezoresistive, dielectric layer and metal leads are produced, and the sensor patterning is realized through photolithography and wet etching technology. and peel off to obtain a pressure sensor chip with high responsiveness.
It realizes a high-pressure ultra-thin pressure sensor production method with low cost, simple process, easy operation and easy storage, solves the problem of breakage in hollow structure design, meets the needs of large-scale mass production, and improves product consistency.
Smart Images
Figure CN119191221A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of silicon chip sensors, and in particular to a method for manufacturing and separating a pressure sensor. Background Art
[0002] Existing ultra-high pressure and ultra-thin pressure sensors are mostly made by using SOL silicon wafers as substrates. The sensor silicon wafers are ground to about 10-20um through mechanical grinding to form the final sensor. This is costly and difficult to operate to remove the chip.
[0003] At present, in the field of high-pressure sensors of 6MPA-20MPa, general MEMS silicon sensor chips are not applicable because the chip production will be damaged in a high-pressure environment. According to the development of technology, the existing silicon strain technology chip can perfectly solve this problem. However, although the sensitivity of this sensor is very high, the thickness is very thin, usually less than 20um; in addition, this high-pressure sensor is made of single-crystal silicon, and silica is a brittle material with poor ductility. Therefore, the production process must be very careful to prevent breakage. Therefore, what needs to be solved now is the problem that the product design is a hollow structure, which is prone to breakage and difficult to sort. Summary of the invention
[0004] The purpose of the present invention is to solve the shortcomings existing in the prior art. The present invention provides a method for manufacturing and separating a pressure sensor. The technical problem to be solved is that the product is designed as a hollow structure, which is easy to break and difficult to sort. A low-cost and simple process method and process flow are provided, which can meet the needs of large-scale mass production and has good consistency.
[0005] In order to achieve the above object, the present invention adopts the following technical solutions:
[0006] A method for manufacturing and separating a pressure sensor, comprising a silicon substrate and a silicon wafer, specifically comprising the following steps:
[0007] 1) The silicon substrate and the silicon wafer are bonded under the protection of silicon oxide to form a new silicon wafer;
[0008] 2) polishing the new silicon wafer to a desired thickness to form a top silicon layer;
[0009] 3) Fabricating piezoresistors, dielectric layers and metal leads on the top silicon layer;
[0010] 4) etching a sensor pattern on the top silicon layer;
[0011] 5) photolithographically patterning and hardening the entire top silicon layer;
[0012] 6) Peeling off the sensor pattern from the top silicon layer and cleaning the surface to obtain a sensor chip.
[0013] Preferred,
[0014] Step 2) polishing the new silicon wafer to a desired thickness by chemical mechanical thinning to form a top silicon layer;
[0015] Step 6) The sensor pattern is peeled off from the top silicon layer by wet etching, and the colloid on the surface is removed by wet etching to obtain a sensor chip.
[0016] Preferred,
[0017] The silicon wafer includes a P-type substrate and a P-type epitaxial layer structure. The resistance value of the P-type substrate is 20Ω to 40Ω, and the thickness of the P-type substrate is greater than 300um; the resistance value of the P-type epitaxial layer structure is 0.03Ω to 0.05Ω, and the thickness is 2um to 10um.
[0018] Preferred,
[0019] The silicon substrate is bonded to the P-type epitaxial layer structure to form a silicon oxide layer with a thickness greater than 1 um between the two.
[0020] Preferred,
[0021] Step 2) When forming the top silicon layer, the thickness of the P-type epitaxial layer structure is thinned to 8um to 20um.
[0022] Preferred,
[0023] Step 3) The method of forming the piezoresistor is as follows:
[0024] ① First, the piezoresistive pattern is formed on the top silicon layer by photolithography;
[0025] ② Secondly, the doped ions are implanted into the silicon material in the piezoresistive pattern region by an ion implantation method;
[0026] ③Finally, piezoresistive material is formed after high temperature annealing.
[0027] Preferred,
[0028] Step 3) The method of forming the medium is as follows:
[0029] ① First, a silicon nitride layer with a thickness of 1um to 4um is formed on the top silicon layer by a CVD method;
[0030] ②Finally, the lead holes connected to the piezoresistor are etched out by photolithography.
[0031] Preferred,
[0032] Step 3) The method of forming the metal lead is as follows:
[0033] ① First, a metal aluminum layer with a thickness of 1um to 3um is formed on the top silicon layer by a PVD method;
[0034] ② Finally, a pattern is formed by photolithography and dry or wet etching to form a metal lead connected to the piezoresistor.
[0035] Preferred,
[0036] Step 4) etching the sensor pattern to a depth down to the position where the silicon substrate and the silicon wafer are bonded in step 1).
[0037] Preferred,
[0038] Step 6) The sensor pattern peeling step is as follows:
[0039] ① First, use wet etching to etch away the oxide layer at the bonding position and completely peel off the entire pattern;
[0040] ②Finally, remove the photoresist on the surface of the sensor chip by wet stripping.
[0041] The beneficial effects of the present invention are:
[0042] The invention provides a method for manufacturing and separating a pressure sensor, which provides a method for manufacturing a high-pressure ultra-thin pressure sensor with low cost, high reaction sensitivity, easy operation, easy transportation and easy storage, simple manufacturing process method and simple manufacturing process flow, and can meet the needs of large-scale mass production with good consistency. It well solves the problem of the hollow structure design existing in the prior art, which makes the product easy to break and difficult to sort. BRIEF DESCRIPTION OF THE DRAWINGS
[0043] Figure 1 A flow chart of a method for manufacturing and separating a pressure sensor proposed by the present invention;
[0044] Figure 2 A schematic diagram of the process of manufacturing and separating a pressure sensor proposed by the present invention. DETAILED DESCRIPTION
[0045] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.
[0046] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0047] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.
[0048] In the description of the present embodiment, the terms "upper", "lower", "left", "right" and other directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation of the present invention. In the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.
[0049] Reference Figure 1-2 , a method for manufacturing and separating a pressure sensor, including a silicon substrate and a silicon wafer, specifically comprising the following steps:
[0050] 1) The silicon substrate and silicon wafer are bonded under the protection of silicon oxide to form a new silicon wafer;
[0051] 2) polishing the new silicon wafer to the required thickness to form a top silicon layer;
[0052] 3) Fabricating piezoresistors, dielectric layers and metal leads on the top silicon layer;
[0053] 4) Etching the sensor pattern on the top silicon layer;
[0054] 5) Photolithography and hardening the entire top silicon layer;
[0055] 6) The sensor pattern is peeled off from the top silicon layer, and the surface is cleaned to obtain a sensor chip.
[0056] Further preference is given to
[0057] Step 2) polishing the new silicon wafer to a desired thickness by chemical mechanical thinning to form a top silicon layer;
[0058] Step 6) The sensor pattern is peeled off from the top silicon layer by wet etching, and then the colloid on the surface is removed by wet etching to obtain a sensor chip.
[0059] Further preference is given to
[0060] The silicon wafer includes a P-type substrate and a P-type epitaxial layer structure. The resistance value of the P-type substrate is 20Ω to 40Ω, and the thickness of the P-type substrate is greater than 300um; the resistance value of the P-type epitaxial layer structure is 0.03Ω to 0.05Ω, and the thickness is 2um to 10um.
[0061] Further preference is given to
[0062] The silicon substrate is bonded to the P-type epitaxial layer structure, forming a silicon oxide layer with a thickness greater than 1 um between the two.
[0063] Further preference is given to
[0064] In step 2), when forming the top silicon layer, the thickness of the P-type epitaxial layer structure is thinned to 8um to 20um.
[0065] Further preference is given to
[0066] Step 3) The method of forming the piezoresistance is as follows:
[0067] ① First, a piezoresistive pattern is formed on the top silicon layer by photolithography;
[0068] ② Secondly, the doped ions are implanted into the silicon material in the piezoresistive pattern area by ion implantation;
[0069] ③Finally, piezoresistive material is formed after high temperature annealing.
[0070] Further preference is given to
[0071] Step 3) The method of forming the medium is as follows:
[0072] ① First, a silicon nitride layer with a thickness of 1um to 4um is formed on the top silicon layer by a CVD method;
[0073] ②Finally, the lead holes connected to the piezoresistors are etched out by photolithography.
[0074] Further preference is given to
[0075] Step 3) The method of forming the metal lead is as follows:
[0076] ① First, a PVD method is used to form a metal aluminum with a thickness of 1um to 3um on the top silicon layer;
[0077] ②Finally, the pattern is formed through photolithography and dry or wet etching to form metal leads connected to the piezoresistor.
[0078] Further preference is given to
[0079] Step 4) etching the sensor pattern to a depth down to the position where the silicon substrate and the silicon wafer are bonded in step 1).
[0080] Further preference is given to
[0081] Step 6) The sensor pattern peeling steps are as follows:
[0082] ① First, use wet etching to etch away the oxide layer at the bonding position and completely peel off the entire pattern;
[0083] ②Finally, remove the photoresist on the surface of the sensor chip by wet stripping.
[0084] A method for manufacturing and separating a pressure sensor is a method for manufacturing and separating a high-pressure ultra-thin pressure sensor, which at least comprises the following steps:
[0085] 1) Providing a silicon substrate and another silicon wafer, completely protecting them by silicon oxide, and bonding the silicon substrate and the silicon wafer together by a bonding method to form a new silicon wafer;
[0086] 2) polishing the new silicon wafer used as the sensitive chip to the desired thickness by chemical mechanical thinning to form a top silicon layer;
[0087] 3) Fabricating piezoresistors, dielectric layers and metal leads in the area positioned on the top silicon layer;
[0088] 4) Use photolithography and dry etching to pattern the sensor;
[0089] 5) Photolithography and hardening the entire top silicon layer;
[0090] 6) The pattern is peeled off from the substrate by wet etching, and then the surface colloid is removed by wet etching to obtain an ultra-thin pressure sensor chip.
[0091] Step 1) Provide a silicon substrate and another silicon wafer, wherein the silicon wafer adopts a P-type substrate plus a P-type epitaxial layer structure, the resistance value of the P-type substrate is 20Ω to 40Ω, the thickness of the P-type epitaxial layer structure is 2um to 10um, the resistance value of the P-type epitaxial layer structure is 0.03Ω to 0.05Ω, and the thickness of the P-type substrate is greater than 300um.
[0092] Step 1) The silicon substrate and the silicon wafer are bonded together by a bonding method. Mainly, the P-type epitaxial layer structure of the silicon substrate and the silicon wafer is bonded to form a layer of silicon oxide between the two layers. The thickness of the oxide layer is greater than 1um.
[0093] Step 2) The new silicon wafer used as the sensitive chip is polished to the required thickness by chemical mechanical thinning to form a top silicon layer. The chemical mechanical thinning method is mainly used to thin the epitaxial layer to a thickness of 8um-20um.
[0094] Step 3) The specific steps of forming the piezoresistor are as follows: forming a piezoresistor pattern on the top silicon layer by photolithography, then implanting doped ions into the silicon material in the piezoresistor pattern area by ion implantation, and forming the piezoresistor after high-temperature annealing.
[0095] Step 3) The specific steps of forming the medium are as follows: a layer of silicon nitride with a thickness of 1um to 4um is formed on the top silicon layer by a CVD method, and then a lead hole is etched by photolithography, and the lead hole is connected to the piezoresistor.
[0096] Step 3) The steps of forming metal leads are as follows: metal aluminum is formed on the top silicon layer by PVD method with a thickness of 1um to 3um, and then a pattern is formed by photolithography and dry or wet etching to form a metal lead, which is connected to the piezoresistor.
[0097] Step 4) Photolithography and dry etching are used to etch out the pattern of the sensor, and the etching depth is limited to the bonding position of step 2).
[0098] Step 5) The entire top silicon layer is patterned and hardened by photolithography; the main purpose is to cover all exposed sensor devices with photoresist to prevent them from falling and being damaged during peeling.
[0099] Step 6) The steps of completely peeling off the sensor are as follows: first, the oxide layer at the bonding position is etched away by wet etching, the entire pattern will be completely peeled off, and then the photoresist on the surface of the sensor chip is removed by wet stripping.
[0100] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims
1. A method for manufacturing and separating a pressure sensor, characterized in that: The method comprises a silicon substrate and a silicon wafer, and specifically comprises the following steps: 1) The silicon substrate and the silicon wafer are bonded under the protection of silicon oxide to form a new silicon wafer; 2) polishing the new silicon wafer to a desired thickness to form a top silicon layer; 3) Fabricating piezoresistors, dielectric layers and metal leads on the top silicon layer; 4) etching a sensor pattern on the top silicon layer; 5) photolithographically patterning and hardening the entire top silicon layer; 6) Peeling off the sensor pattern from the top silicon layer and cleaning the surface to obtain a sensor chip.
2. The method for manufacturing and separating a pressure sensor according to claim 1, characterized in that: Step 2) polishing the new silicon wafer to a desired thickness by chemical mechanical thinning to form a top silicon layer; Step 6) The sensor pattern is peeled off from the top silicon layer by wet etching, and the colloid on the surface is removed by wet etching to obtain a sensor chip.
3. The method for manufacturing and separating a pressure sensor according to claim 1, characterized in that: The silicon wafer comprises a P-type substrate and a P-type epitaxial layer structure, the resistance value of the P-type substrate is 20Ω to 40Ω, and the thickness of the P-type substrate is greater than 300um; The P-type epitaxial layer structure has a resistance value of 0.03Ω to 0.05Ω and a thickness of 2um to 10um.
4. The method for manufacturing and separating a pressure sensor according to claim 3, characterized in that: The silicon substrate is bonded to the P-type epitaxial layer structure to form a silicon oxide layer with a thickness greater than 1 um between the two.
5. The method for manufacturing and separating a pressure sensor according to claim 2, characterized in that: Step 2) When forming the top silicon layer, the thickness of the P-type epitaxial layer structure is thinned to 8um to 20um.
6. The method for manufacturing and separating a pressure sensor according to claim 2, characterized in that: Step 3) The method of forming the piezoresistor is as follows: ① First, the piezoresistive pattern is formed on the top silicon layer by photolithography; ② Secondly, the doped ions are implanted into the silicon material in the piezoresistive pattern region by an ion implantation method; ③Finally, piezoresistive material is formed after high temperature annealing.
7. The method for manufacturing and separating a pressure sensor according to claim 2, characterized in that: Step 3) The method of forming the medium is as follows: ① First, a silicon nitride layer with a thickness of 1um to 4um is formed on the top silicon layer by a CVD method; ②Finally, the lead holes connected to the piezoresistor are etched out by photolithography.
8. The method for manufacturing and separating a pressure sensor according to claim 2, characterized in that: Step 3) The method of forming the metal lead is as follows: ① First, a metal aluminum layer with a thickness of 1um to 3um is formed on the top silicon layer by a PVD method; ② Finally, a pattern is formed by photolithography and dry or wet etching to form a metal lead connected to the piezoresistor.
9. The method for manufacturing and separating a pressure sensor according to claim 2, characterized in that: Step 4) etching the sensor pattern to a depth down to the position where the silicon substrate and the silicon wafer are bonded in step 1).
10. The method for manufacturing and separating a pressure sensor according to claim 2, characterized in that: Step 6) The sensor pattern peeling step is as follows: ① First, use wet etching to etch away the oxide layer at the bonding position and completely peel off the entire pattern; ②Finally, remove the photoresist on the surface of the sensor chip by wet stripping.