Manufacturing method of complementary oxidized metal semiconductor sound pressure sensor

Abstract

The invention discloses a manufacturing method of a complementary metal oxide semiconductor sound pressure sensor, which comprises the following steps of: etching a complementary metal oxide semiconductor wafer substrate after a complementary metal oxide semiconductor manufacturing process is finished; and separating the sound pressure sensor area from the wafer substrate and removing part of the oxidation insulation structure in the middle of the complementary oxidized metal semiconductor wafer, so that the manufacturing of the complementary oxidized metal semiconductor sound pressure sensor can be completed.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a sound pressure sensor, and more particularly to a method for manufacturing a complementary metal oxide semiconductor sound pressure sensor. Background Art

[0002] Complementary metal oxide semiconductor (CMOS) has been widely used in integrated circuits. (IC) manufacturing, especially in high-end smartphone chips and image sensor chips (CIS). Due to a large amount of research manpower and investment, the development and innovation of integrated circuits have made rapid progress, significantly improving their reliability and output, while significantly reducing production costs. At present, this technology has reached a mature and stable level. For the continued development of semiconductors, in addition to keeping up with the current technological development trends, it is necessary to achieve breakthroughs, provide special production processes, and enhance system integration.

[0003] In this regard, micro-electromechanical systems (MEMS) are a new processing technology that is completely different from traditional technologies. It mainly uses semiconductor technology to produce MEMS structures; at the same time, it can manufacture structures with electronic and mechanical functions. Therefore, it has the advantages of batch processing, miniaturization and high performance, and is very suitable for technologies that need to be mass-produced at a reduced cost. Therefore, for CMOS circuit integration and MEMS combined together, it can be the best way to achieve system integration. In traditional technology, as shown in Figure 1, a micro-electromechanical capacitive sound pressure sensor 1 usually has a fixed electrode 6, an insulating layer 10, a conductive film 12 and a semiconductor substrate 14. There is a gap between the fixed electrode 7 and the conductive film 12, and the semiconductor substrate 14 is provided with a cavity 16, and the cavity 16 is located below the conductive film 12. When the sound pressure is transmitted to the conductive film 12 through air vibration, the conductive film 12 will vibrate. When the conductive film 12 vibrates up and down, a capacitance change will occur between the conductive film 12 and the fixed electrode 7, and the sound pressure change can be obtained by converting the capacitance change into a voltage signal. US Patent 8692340 uses two different process semiconductor substrates to perform CMOS process and MEMS process respectively, and then uses wafer bonding to form an acoustic pressure sensor. However, this technology has a high manufacturing cost and cannot be arrayed.

[0004] Therefore, the present invention aims at the above-mentioned problems and proposes a method for manufacturing a complementary metal oxide semiconductor sound pressure sensor to solve the problems arising from the prior art. Summary of the invention

[0005] The main purpose of the present invention is to provide a method for manufacturing a complementary metal oxide semiconductor acoustic pressure sensor, which can improve the performance of the sensor and reduce the production and testing costs.

[0006] To achieve the above-mentioned purpose, the present invention provides a method for manufacturing a complementary metal oxide semiconductor sound pressure sensor. First, a complementary metal oxide semiconductor process is provided, which includes a semiconductor substrate, a first oxide insulating layer, a doped polysilicon layer, a second oxide insulating layer, and a metal wiring layer arranged in sequence from bottom to top. In the complementary metal oxide semiconductor process, there are usually multiple metal wiring layers, and the middle of each metal wiring layer is an oxide insulating layer or a metal through hole (VIA). Therefore, there is usually at least one doped polysilicon layer and one metal wiring layer in the complementary metal oxide semiconductor process. In the manufacture of the sensor, reactive ion etching can be used to remove the oxide insulating layer in the complementary metal oxide semiconductor process and inductively coupled plasma can be used to etch the substrate to complete the cavity, thereby forming a complementary metal oxide semiconductor sound pressure sensor.

[0007] In one embodiment of the present invention, the metal wiring layer further includes a plurality of patterned metal layers and a plurality of metal through holes, which are sensing electrodes. The film is made of polysilicon, the sensing electrode is connected to the film, and the other end of the sensing electrode is a fixed end.

[0008] In one embodiment of the present invention, the metal wiring layer further includes a plurality of patterned metal layers and a plurality of metal through holes, which are sensing electrodes. The film is composed of an oxide insulating layer and polysilicon, the sensing electrode is connected to the film, and the other end of the sensing electrode is a fixed end.

[0009] In one embodiment of the present invention, the metal wiring layer further comprises a plurality of patterned metal layers and a plurality of metal through holes, which are sensing electrodes. The film is composed of an oxide insulating layer and a metal wiring layer, the sensing electrode is connected to the film, and the other end of the sensing electrode is a fixed end.

[0010] The metal wiring layer further includes a plurality of patterned metal layers and a plurality of metal through holes, which are sensing electrodes. The film is composed of an oxide insulating layer, polysilicon and a metal wiring layer, the sensing electrode is connected to the film, and the other end of the sensing electrode is a fixed end.

[0011] In one embodiment of the present invention, the CMOS sound pressure sensor may be an array sensor, where a plurality of CMOS sound pressure sensors of the same size are arranged in one chip.

[0012] In one embodiment of the present invention, the CMOS sound pressure sensor may be an array sensor, where a plurality of CMOS sound pressure sensors of different sizes are arranged in one chip.

[0013] In one embodiment of the present invention, the polysilicon layer further includes undoped polysilicon, where the undoped polysilicon is a non-conductor.

[0014] Based on the above, the manufacturing method of complementary metal oxide semiconductor sound pressure sensor can effectively improve the sensor performance and reduce the testing and packaging cost.

[0015] In order to enable you, the examiner, to have a better understanding and knowledge of the structural features and effects achieved by the present invention, we hereby provide a preferred embodiment diagram and a detailed description, as follows: BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 is a cross-sectional view of the structure of a MEMS capacitive sound pressure sensor of the prior art.

[0017] FIG. 2( a ) to FIG. 2( c ) are cross-sectional views of the structures of the various steps of manufacturing the first embodiment of the complementary metal oxide semiconductor sound pressure sensor of the present invention.

[0018] FIG. 3 is a top view of the sensing structure of the second embodiment of the present invention.

[0019] FIG. 4 is a cross-sectional view of the structure along line AA' of FIG. 3.

[0020] FIG. 5 is a top view of the structure of an array-type complementary metal oxide semiconductor sound pressure sensor of the same size according to the third embodiment of the present invention.

[0021] FIG. 6 is a top view of the structure of array-type complementary metal oxide semiconductor sound pressure sensors of different sizes according to the fourth embodiment of the present invention.

[0022] Explanation of reference numerals: 1-microelectromechanical capacitive sound pressure sensor; 2-complementary metal oxide semiconductor process; 3-shielding; 4-shielding; 5-sensing structure; 6-fixed electrode; 7-array-type complementary metal oxide semiconductor sound pressure sensors of the same size; 8-array-type complementary metal oxide semiconductor sound pressure sensors of different sizes; 10-insulating layer; 12-conductive film; 14-semiconductor substrate; 16-cavity; 17-multi-layer sensing electrode; 18-multi-layer fixed electrode; 20-semiconductor substrate; 21-first oxide insulating layer; 22-polysilicon layer; 23-second oxide insulating layer; 24-metal wiring layer; 25-metal through hole; 26-thin film; 100-oxide insulating structure DETAILED DESCRIPTION

[0023] The embodiments of the present invention will be further explained below with reference to the accompanying drawings. As far as possible, the same reference numerals in the drawings and the specification represent the same or similar components. In the drawings, the shapes and thicknesses may be exaggerated for simplicity and convenience. It is understood that the components not specifically shown in the drawings or described in the specification are known to those skilled in the art. Those skilled in the art may make various changes and modifications based on the contents of the present invention.

[0024] When a component is referred to as being "on...", it can generally mean that the component is directly on other components or that other components exist between them. Conversely, when a component is referred to as being "directly on" another component, it can mean that other components cannot exist between them. As used herein, the term "and / or" includes any combination of one or more of the associated listed items.

[0025] The description of "one embodiment" or "an embodiment" in the following text refers to a specific component, structure or feature associated with at least one embodiment. Therefore, multiple descriptions of "one embodiment" or "an embodiment" appearing in multiple places in the following text do not refer to the same embodiment. Furthermore, specific components, structures and features in one or more embodiments may be combined in an appropriate manner.

[0026] The present invention is particularly described with the following examples, which are only used for illustration, because for those skilled in the art, various changes and modifications can be made without departing from the spirit and scope of the present invention, so the protection scope of the present invention should be determined by the attached claims. Throughout the specification and claims, unless the content clearly specifies, the meaning of "one" and "the" includes this type of description including "one or at least one" described components or ingredients. In addition, as used in the present invention, unless it is obvious from the specific context that the plurality is excluded, the singular article also includes the description of plural components or ingredients. Moreover, when applied in this description and all the claims below, unless the content clearly specifies, the meaning of "in which" may include "in which" and "on it". The terms used in the specification and claims, unless otherwise specified, generally have the ordinary meaning of each term used in this field, in the content provided herein and in the special content. Certain terms used to describe the present invention will be discussed below or elsewhere in this specification to provide practitioners with additional guidance in describing the present invention. The use of examples anywhere throughout the specification, including examples of any term discussed herein, is for illustrative purposes only and certainly does not limit the scope and meaning of the present invention or any exemplified term. Likewise, the present invention is not limited to the various embodiments set forth in this specification.

[0027] It is understood that the terms "comprising", "including", "having", "containing", "involving", etc. used herein are open-ended, that is, they mean including but not limited to. In addition, any embodiment or claim of the present invention is not required to achieve all the purposes, advantages or features provided by the present invention. In addition, the abstract part and the title are only used to assist in searching patent documents and are not used to limit the scope of the invention.

[0028] Unless otherwise specified, some conditional sentences or words, such as "can", "could", "might", or "may", are generally intended to express that the embodiment of the present case has, but can also be interpreted as features, components, or steps that may not be required. In other embodiments, these features, components, or steps may not be required.

[0029] The following will introduce a method for manufacturing a complementary metal oxide semiconductor sound pressure sensor, which uses a standard complementary metal oxide semiconductor (CMOS) process to reduce manufacturing costs and improve performance. Generally speaking, polysilicon in the complementary metal oxide semiconductor process is doped with N-type or P-type ions to serve as a conductive material, which can usually be used as a gate, resistor or polysilicon (PIP, poly interconnect poly) capacitor. When manufacturing a complementary metal oxide semiconductor sound pressure sensor, it is used as an RIE etching stop layer and can also define a smaller gap.

[0030] FIG. 2(a) to FIG. 2(c) are cross-sectional views of the structures of each step of the first embodiment of the present invention for making a complementary metal oxide semiconductor sound pressure sensor. Please refer to FIG. 2(a) to FIG. 2(c) below to introduce the first embodiment of the method for making a complementary metal oxide semiconductor sound pressure sensor of the present invention. First, as shown in FIG. 2(a), a complementary metal oxide semiconductor device 2 is provided, which includes a semiconductor substrate 20, a first oxide insulating layer 21, a doped polysilicon layer 22, a second oxide insulating layer 23, and a metal wiring layer 24 arranged in sequence from bottom to top. The semiconductor substrate 20 can be, but not limited to, a silicon substrate. The first oxide insulating layer 21 and the second oxide insulating layer 23 can be silicon dioxide layers, but the present invention is not limited thereto. The polysilicon layer 22 can be a multi-layer polysilicon layer, which means that a polysilicon layer can be added above the second oxide insulating layer 23 in the complementary metal oxide semiconductor device. There is no special illustration in this article, and this is a conventional technology. The metal wiring layer 24 is disposed on the second oxide insulating layer 23, wherein the metal wiring layer is composed of a multi-layer metal wiring layer, an oxide insulating layer and a metal through hole (VIA) 25. The metal through hole (VIA) 25 is between the metal wiring layer 24 and the polysilicon layer 22 for electrical conduction. The doped polysilicon layer 22 may include undoped polysilicon. Here, the multi-layer oxide insulating layer and the multi-layer metal wiring layer have the same properties and functions, and are used for insulation and conductive line numbers. If there is no special purpose or other function, the difference is only in the icon description. For example, the first oxide insulating layer and the second oxide insulating layer function as insulation.

[0031] Next, as shown in FIG. 2( b), an inductively coupled plasma is used to remove a portion of the semiconductor substrate to form a cavity 16, the cavity being located below the polysilicon layer 22, and a shield 3 being located in the non-etched area of ​​the semiconductor substrate 14, the shield 3 being a photoresist or thermally formed silicon dioxide. After removing a portion of the semiconductor substrate, the shield 3 is removed at the same time. In addition, chemical etching is also used to form the cavity.

[0032] As shown in FIG. 2( c ), the shield 4 is above the metal wiring layer, and the shield 4 is a photoresist material. Reactive ion etching is used to remove the oxide insulating structure 100 to form a multi-layer sensing electrode 17 connected to the thin film 26, and then the shield 4 and the first oxide insulating layer 21 are removed. Here, the thin film may be composed of a polysilicon layer 22, an oxide insulating layer 21 and a metal wiring layer 24, and the thin film may also have only a polysilicon layer 22. The composition of the multi-layer sensing electrode 17 includes a metal wiring layer 24, an oxide insulating layer 23 and a metal through hole (VIA) 25.

[0033] FIG. 3 is a top view of the sensing structure of the second embodiment of the present invention, and FIG. 4 is a cross-sectional view of the structure along line A-A' of FIG. 3. The second embodiment of the complementary metal oxide semiconductor sound pressure sensor is introduced below, and its sensing structure 5 includes a thin film, a multi-layer sensing electrode 17 and a multi-layer fixed electrode 18. Here, if the polysilicon layer is a conductor, the sensing electrode and the fixed electrode are at the same potential. Here, the difference between the multi-layer sensing electrode 17 and the multi-layer fixed electrode 18 is particularly explained. When the thin film is displaced by the sound pressure, the multi-layer sensing electrode 17 will also be displaced, but the multi-layer fixed electrode 18 will not be displaced.

[0034] FIG5 shows a third embodiment of the present invention, an array type CMOS sound pressure sensor 7 of the same size. The array type CMOS sound pressure sensor of the same size is composed of a plurality of sensing structures 5 of the same size and a cavity 16.

[0035] FIG6 shows a fourth embodiment of the present invention, which is an array type CMOS sound pressure sensor 8 of different sizes. The array type CMOS sound pressure sensor of different sizes is composed of a plurality of sensing structures 5 of different sizes and a cavity 16.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Therefore, all equivalent changes and modifications based on the shape, structure, characteristics and spirit described in the claims of the present invention should be included in the scope of the present invention.

Claims

1. A method for manufacturing a complementary metal oxide semiconductor acoustic pressure sensor, comprising the following steps: providing a complementary metal oxide semiconductor device, etching a semiconductor substrate and removing an oxide insulating structure using reactive ion etching. After etching, the acoustic pressure sensor comprises a film, a cavity, a multi-layer sensing electrode and a multi-layer fixed electrode, and the sensing electrode is connected to the film.

2. The method for manufacturing a complementary metal oxide semiconductor acoustic pressure sensor as described in claim 1, wherein the etching of the semiconductor substrate can be performed by inductively coupled plasma or chemical etching.

3. The method for manufacturing a complementary metal oxide semiconductor acoustic pressure sensor as described in claim 1, wherein the polysilicon layer in the thin film can be a non-conductor or an equipotential conductor.

4. A method for manufacturing an array type complementary metal oxide semiconductor sound pressure sensor, comprising the following steps: A complementary metal oxide semiconductor device is provided, a semiconductor substrate is etched and an oxide insulating structure is removed by reactive ion etching. After etching, a plurality of sound pressure sensors are provided, including a film, a cavity, a multi-layer sensing electrode and a multi-layer fixed electrode, and the sensing electrode is connected to the film.

5. A method for manufacturing an array of complementary metal oxide semiconductor sound pressure sensors as described in claim 4, wherein the sound pressure sensors have different sizes.

6. The method for manufacturing an array-type complementary metal oxide semiconductor sound pressure sensor as described in claim 4, wherein the polysilicon layer in the thin film can be a non-conductor or an equipotential conductor.

7. The method for manufacturing an array type complementary metal oxide semiconductor acoustic pressure sensor as described in claim 4, wherein the etching of the semiconductor substrate can be performed by inductively coupled plasma or chemical etching.

8. A complementary metal oxide semiconductor acoustic pressure sensor, comprising a complementary metal oxide semiconductor device and an acoustic pressure sensor, wherein the acoustic pressure sensor comprises a membrane, a cavity, a multi-layer sensing electrode and a multi-layer fixed electrode, and the sensing electrode is connected to the membrane.

9. The complementary metal oxide semiconductor sound pressure sensor as described in claim 8, wherein the polysilicon layer in the thin film can be a non-conductor or an equipotential conductor.

10. The complementary metal oxide semiconductor acoustic pressure sensor as claimed in claim 8, wherein the thin film comprises at least one polysilicon layer.

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