TWI808926B - Fabrication method of complementary metal oxide semi-microelectromechanical pressure sensor - Google Patents

Abstract

The invention discloses a manufacturing method of a complementary metal-oxide-semiconductor micro-electromechanical pressure sensor. First, a complementary metal-oxide-semiconductor device is provided, which includes a semiconductor substrate, a first oxide insulating layer, a doped polysilicon layer, a second oxide insulating layer, a patterned polysilicon layer, and a metal wiring layer arranged sequentially from bottom to top. The patterned polysilicon layer includes undoped polysilicon. Next, remove the exposed oxide insulation structure of the metal wiring layer, and form a first metal layer on the second oxide insulation layer, the patterned polysilicon layer and the metal wiring layer. In addition, a portion of the first metal layer and a portion of the oxidized insulating structure are removed to expose the undoped polysilicon, and a cavity and a hole are formed. A second metal layer is formed on the first metal layer to seal the hole.

Description

Fabrication method of complementary metal oxide semi-microelectromechanical pressure sensor

The present invention relates to a manufacturing method of a pressure sensor, and in particular to a manufacturing method of a complementary metal-oxygen semi-microelectromechanical pressure sensor.

Over the past three decades, complementary metal-oxide semiconductors (CMOS) have been widely used in the fabrication of integrated circuits (ICs). Thanks to a large amount of research manpower and investment, the development and innovation of integrated circuits has made rapid progress, significantly improving their reliability and yield, and at the same time, the production cost has been greatly reduced. At present, this technology has reached a mature and stable level. For the sustainable development of semiconductors, in addition to keeping up with the current technological development trend, breakthroughs must be achieved, special production processes must be provided, and system integration must be enhanced.

In this regard, microelectromechanical systems (MEMS) are a new processing technology that is completely different from conventional technologies. It mainly uses semiconductor technology to produce MEMS structures; at the same time it is able to manufacture products with electronic and mechanical functions. Therefore, it has the advantages of batch processing, miniaturization, and high performance, and is very suitable for production industries that require mass production at reduced costs. Therefore, for this stable and growing CMOS technology, the integration of MEMS and circuits can be a better way to achieve system integration. In the conventional technology, as shown in FIG. 1 , the MEMS pressure sensor usually has a semiconductor substrate 10 and a metal structure 12 . There is a cavity between the semiconductor substrate 10 and the metal structure 12 . When pressure is exerted on the metal structure 12, the metal structure 12 is dented. If there is an error in the manufacturing process, a short circuit will occur between the semiconductor substrate 10 and the metal structure 12 . In order to avoid short circuit, US Pat. No. 8,794,075 uses a nitride layer to avoid short circuit between the metal structure and the semiconductor substrate, and the nitride layer is not a material used in the standard process. US Patent No. 9540230 performs CMOS process and MEMS process on two semiconductor substrates respectively, and then integrates the structures on the two semiconductor substrates into a pressure sensor. However, the cost of this technique is relatively high.

Therefore, the present invention is aimed at the above problems, and proposes a manufacturing method of a complementary metal oxide semi-microelectromechanical pressure sensor to solve the conventional problems.

The main purpose of the present invention is to provide a manufacturing method of a complementary metal oxide semi-microelectromechanical pressure sensor, which can reduce the cost and avoid the short circuit between the doped polysilicon layer and the metal layer.

To achieve the above purpose, the present invention provides a method for manufacturing a complementary metal oxide semi-microelectromechanical pressure sensor. Firstly, a complementary metal-oxide-semiconductor device is provided, which includes a semiconductor substrate, a first oxide insulating layer, a doped polysilicon layer, a second oxide insulating layer, a patterned polysilicon layer and a metal wiring layer sequentially arranged from bottom to top. The metal wiring layer is disposed on the second insulating oxide layer and the patterned polysilicon layer. The patterned polysilicon layer includes undoped polysilicon. The second insulating oxide layer has an inner region and an outer region surrounding the inner region. The undoped polysilicon is located on the inner region, and the metal wiring layer includes an oxide insulation structure exposed outside and arranged on the undoped polysilicon. Next, a mask is formed on the metal wiring layer directly above the inner region to remove the oxide insulation structure directly above the outer region, thereby exposing the second oxide insulation layer and the patterned polysilicon layer. Next, the mask is removed, and a first metal layer is formed on the second oxide insulating layer, the patterned polysilicon layer and the metal wiring layer. Then, removing the part of the first metal layer and the oxidation insulating structure directly above the inner region to expose the undoped polysilicon, and forming a cavity communicating with the hole directly above the inner region. Finally, a second metal layer is formed on the first metal layer to seal the hole, so as to form a complementary metal oxide semi-microelectromechanical pressure sensor.

In an embodiment of the present invention, the metal wiring layer further includes a plurality of patterned metal layers and a plurality of metal vias, all the patterned metal layers are embedded in the oxide insulating structure, and all the patterned metal layers are separated from each other and arranged sequentially from bottom to top. The lowermost patterned metal layer is separated from the patterned polysilicon layer, and all metal vias penetrate through the oxide insulating structure and all the patterned metal layers. One end of each metal via is located on the inner region of the second oxide insulating layer, and the other end is exposed outside. The uppermost patterned metal layer has an opening through itself, the opening is located directly above the inner region, and is filled with an oxide insulating structure. The mask is located on the uppermost patterned metal layer and the oxide insulation structure, and the first metal layer is located on the oxide insulation structure, all the patterned metal layers and all the metal vias.

In one embodiment of the present invention, the removal method of the part of the first metal layer and the oxide insulating structure immediately above the inner region is wet etching or etching with hydrogen fluoride vapor (HF vapor).

In an embodiment of the present invention, the material of the mask is a non-hydrofluoric acid etchable semiconductor material.

In one embodiment of the present invention, a manufacturing method of a complementary metal-oxide-semiconductor micro-electromechanical pressure sensor includes the following steps: providing a complementary metal-oxide-semiconductor device, which includes a semiconductor substrate, a first insulating oxide layer, a doped polysilicon layer, a second insulating oxide layer, a patterned polysilicon layer, and a metal wiring layer, wherein the metal wiring layer is disposed on the second insulating oxide layer and the patterned polysilicon layer, the patterned polysilicon layer includes undoped polysilicon, and the second insulating oxide layer has an inner region and an outer region surrounding the inner region, undoped polysilicon is located on the inner region, and the metal wiring layer includes an oxide insulating structure exposed outside and disposed on the undoped polysilicon; forming a mask on the metal wiring layer directly above the inner region to remove the oxide insulating structure directly above the outer region to expose the second oxide insulating layer and the patterned polysilicon layer; removing the mask and the oxide insulating structure directly above the inner region to expose the undoped polysilicon, and forming an opening directly above the inner region to communicate with the cavity; A sealing metal layer is formed on the second oxide insulating layer, the patterned polysilicon layer and the metal wiring layer to seal the opening, thereby forming a complementary metal oxide semi-microelectromechanical pressure sensor.

In an embodiment of the present invention, the metal wiring layer further includes a plurality of patterned metal layers and a plurality of metal vias, all the patterned metal layers are embedded in the oxide insulating structure, and all the patterned metal layers are separated from each other and arranged sequentially from bottom to top. The lowermost patterned metal layer is separated from the patterned polysilicon layer, and all metal vias penetrate through the oxide insulating structure and all the patterned metal layers. One end of each metal via is located on the inner region of the second oxide insulating layer, and the other end is exposed outside. The uppermost patterned metal layer has an opening through itself, and the opening is filled with an oxide insulating structure. The mask is located on the uppermost patterned metal layer and the oxide insulation structure, and the sealing metal layer is located on the oxide insulation structure, all the patterned metal layers and all the metal vias.

In an embodiment of the present invention, the removal method of the oxide insulating structure right above the inner region is wet etching or etching with hydrogen fluoride vapor (HF vapor).

In an embodiment of the present invention, the material of the mask is a non-hydrofluoric acid etchable semiconductor material.

In one embodiment of the present invention, a manufacturing method of a complementary metal-oxide-semiconductor micro-electromechanical pressure sensor includes the following steps: providing a complementary metal-oxide-semiconductor device, which includes a semiconductor substrate, a first insulating oxide layer, a doped polysilicon layer, a second insulating oxide layer, a patterned polysilicon layer, and a metal wiring layer, wherein the metal wiring layer is disposed on the second insulating oxide layer and the patterned polysilicon layer, the patterned polysilicon layer includes undoped polysilicon, and the second insulating oxide layer has An inner area and an outer area surrounding the inner area. Undoped polysilicon is located on the inner area. The metal wiring layer includes an oxide insulating structure exposed outside and disposed on the undoped polysilicon, a plurality of patterned metal layers and a ring-shaped metal via hole. All patterned metal layers are embedded in the oxide insulation structure. All patterned metal layers are separated from each other and arranged from bottom to top. One end of the annular metal via hole is located on the inner region of the second oxide insulating layer, and the other end is exposed outside. The uppermost patterned metal layer has an opening through itself. The opening is located directly above the inner region and filled with the oxide insulating structure; the oxide insulating structure directly above the inner region is removed to expose undoped polysilicon, and a cavity connected to the opening is formed directly above the inner region; force sensor.

In an embodiment of the present invention, the removal method of the oxide insulating structure right above the inner region is wet etching or etching with hydrogen fluoride vapor (HF vapor). In an embodiment of the present invention, the material of the oxide insulating structure is silicon dioxide.

In an embodiment of the present invention, the patterned polysilicon layer further includes doped polysilicon.

Based on the above, the manufacturing method of the complementary metal-oxide-semi-microelectromechanical pressure sensor uses a low-cost standard complementary metal-oxide-semiconductor process to form a patterned polysilicon layer, and uses the undoped polysilicon of the patterned polysilicon layer to isolate the doped polysilicon layer and the metal layer to avoid short circuits between the doped polysilicon layer and the metal layer.

In order to make your review committee members have a further understanding and understanding of the structural features and the achieved effects of the present invention, I would like to provide a better embodiment diagram and a detailed description, as follows:

Embodiments of the present invention will be further explained in conjunction with related figures below. Wherever possible, the same reference numerals have been used throughout the drawings and description to refer to the same or similar components. In the drawings, the shape and thickness may be exaggerated for the sake of simplification and convenient labeling. It should be understood that elements not particularly shown in the drawings or described in the specification are forms known to those skilled in the art. Those skilled in the art can make various changes and modifications according to the content of the present invention.

When an element is referred to as being "on", it can generally mean that the element is directly on other elements, or there may be other elements present in between. Conversely, when an element is referred to as being "directly on" another element, it cannot have the other element in between. As used herein, the word "and/or" includes any combination of one or more of the associated listed items.

The following descriptions of "one embodiment" or "an embodiment" refer to at least one specific element, structure or feature associated with one embodiment. Therefore, multiple descriptions of "one embodiment" or "an embodiment" appearing in various places below 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.

The disclosure 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 disclosure, so the protection scope of the disclosure should be defined by the scope of the appended patent application. Throughout the specification and claims, the meanings of "a" and "the" include that such description includes "one or at least one" of the element or component, unless the content clearly specifies otherwise. Furthermore, as used in the present disclosure, singular articles also include descriptions of plural elements or components, unless it is obvious from the specific context that the plural is excluded. Also, as applied in this description and all claims below, the meaning of "in" may include "in" and "on" unless the content clearly dictates otherwise. The terms (terms) used throughout the specification and patent claims generally have the ordinary meaning of each term used in this field, in the content of this disclosure and in the specific content, unless otherwise specified. Certain terms used to describe the disclosure are discussed below or elsewhere in this specification to provide practitioners with additional guidance in describing the disclosure. The use of examples anywhere throughout the specification, including examples of any terms discussed herein, is for illustration only and certainly does not limit the scope and meaning of the disclosure or any exemplified terms. Likewise, the present disclosure is not limited to the various embodiments presented in this specification.

It can be understood that the terms "comprising", "including", "having", "containing", "involving", etc. as used herein are open-ended, meaning including but not limited to. In addition, any embodiment or scope of claims of the present invention does not necessarily achieve all the objectives or advantages or features disclosed in the present invention. In addition, the abstract and title are only used to assist in the search of patent documents, and are not used to limit the scope of patent applications for inventions.

Unless otherwise specified, some conditional sentences or words, such as "can (can)", "could (could)", "maybe (might)", or "may (may)", are generally intended to express that the embodiment of the present case has, but can also be interpreted as a feature, element, or step that may not be required. In other embodiments, these features, elements, or steps may not be required.

The following will introduce a manufacturing method of a complementary metal-oxide-semiconductor microelectromechanical pressure sensor, which uses a standard complementary metal-oxide-semiconductor (CMOS) process to reduce manufacturing costs. Generally speaking, polysilicon in the CMOS process is doped with N-type or P-type ions as a conductive material, which can usually be used as gates, resistors, or polysilicon (PIP, poly interconnect poly) capacitors. However, the present invention does not dope any ions in the polysilicon, that is, pure polysilicon can be used as an etching barrier when making CMOS micro-electromechanical pressure sensors, and can also prevent short circuits in pressure sensors.

Figure 2(a) to Figure 2(e) are cross-sectional views of the structure of each step in the first embodiment of the complementary metal oxide semi-microelectromechanical pressure sensor of the present invention. Please refer to FIG. 2(a) to FIG. 2(e) below to introduce the first embodiment of the manufacturing method of the complementary metal oxide semi-microelectromechanical 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, a patterned polysilicon layer 24, and a metal wiring layer 25 arranged in sequence from bottom to top. The semiconductor substrate 20 may be, but not limited to, a silicon substrate. The first insulating oxide layer 21 and the second insulating oxide layer 23 may be silicon dioxide layers, but the present invention is not limited thereto. The metal wiring layer 25 is disposed on the second insulating oxide layer 23 and the patterned polysilicon layer 24 . The patterned polysilicon layer 24 may only include undoped polysilicon 240 or include undoped polysilicon 240 and doped polysilicon 241 . If the patterned polysilicon layer 24 only includes undoped polysilicon, the material of the entire area of the patterned polysilicon layer 24 is undoped polysilicon. In the first embodiment, the patterned polysilicon layer 24 includes both undoped polysilicon 240 and doped polysilicon 241 as an example. In other words, the material of a part of the patterned polysilicon layer 24 is undoped polysilicon 240 , and the material of the rest of the patterned polysilicon layer 24 is doped polysilicon 241 , wherein the undoped polysilicon 240 area is indicated by hatching, and the doped polysilicon 241 area is indicated by a blank. The doped polysilicon 241 used in the present invention can be doped with P-type ions or N-type ions, and is more conductive than the undoped polysilicon 240 . In addition, the undoped polysilicon 240 used in the present invention is pure polysilicon. According to EFFECT OF GRAIN STRUCTURE AND DOPING ON THE MECHANICAL PROPERTIES OF POLYSILICON THIN FILMS FOR MEMS written by NAGA SIVAKUMAR YAGNAMURTHY in 2013, the resistivity of undoped polysilicon is infinite. The resistivity of undoped polysilicon is lower than that of undoped polysilicon, so the undoped polysilicon used in the present invention can be regarded as an insulator and used to prevent short circuit between two conductors. The second insulating oxide layer 23 has an inner region 230 and an outer region 231 surrounding the inner region 230 . The undoped polysilicon 240 is located on the inner region 230 , and the metal wiring layer 25 includes an oxide insulating structure 250 exposed outside and disposed on the undoped polysilicon 240 . For example, the material of the oxide insulating structure 250 can be, but not limited to, silicon dioxide.

In order to illustrate the manufacturing method of the complementary metal oxide semi-microelectromechanical pressure sensor of the present invention, the structure of the metal wiring layer 25 is specifically described, but the present invention is not limited thereto. In some embodiments of the present invention, the metal wiring layer 25 may further include a plurality of patterned metal layers 251 and a plurality of metal vias (vias) 252 . The material of the patterned metal layer 251 can be, but not limited to, aluminum. Both the patterned metal layer 251 and the metal via 252 are conductive materials. All the patterned metal layers 251 are embedded in the oxide insulating structure 250 , and all the patterned metal layers 251 are separated from each other and arranged sequentially from bottom to top, and the bottommost patterned metal layer 251 is separated from the patterned polysilicon layer 24 . All the metal vias 252 penetrate through the oxide insulating structure 250 and all the patterned metal layers 251 . One end of each metal via 252 is located on the inner region 230 of the second oxide insulating layer 23 , and the other end is exposed outside. The uppermost patterned metal layer 251 has an opening 2510 passing through it. The opening 2510 is located directly above the inner region 230 and filled with the oxide insulating structure 250 .

Next, as shown in FIG. 2(b), a mask 3 is formed on the metal wiring layer 25 directly above the inner region 230 to remove the oxide insulating structure 250 directly above the outer region 231, thereby exposing the second oxide insulating layer 23 and the doped polysilicon 241 of the patterned polysilicon layer 24. Specifically, the mask 3 is located on the uppermost patterned metal layer 251 and the oxide insulating structure 250 . For example, the material of the mask 3 can be realized by non-hydrofluoric acid etchable semiconductor material, such as metal, silicon, silicon carbide or photoresist, but the invention is not limited thereto. In addition, the removal method of the oxide insulating structure 250 right above the outer region 231 may be, but not limited to, reactive ion etching.

As shown in FIG. 2( c ), the mask 3 is removed, and a first metal layer 26 is formed on the second oxide insulating layer 23 , the doped polysilicon 241 of the patterned polysilicon layer 24 and the metal wiring layer 25 . The material of the first metal layer 26 can be, but not limited to, aluminum. Specifically, the first metal layer 26 is located on the oxide insulating structure 250 of the metal wiring layer 25 , all the patterned metal layers 251 and all the metal vias 252 . As shown in FIG. 2(d), the portion of the first metal layer 26 directly above the inner region 230 and the oxide insulating structure 250 are removed to expose the undoped polysilicon 240, and a cavity 27 is formed directly above the inner region 230 to form a hole 28 communicating with it. The portion of the first metal layer 26 directly above the inner region 230 and the oxide insulating structure 250 can be removed by, but not limited to, wet etching or etching with hydrogen fluoride vapor (HF vapor).

As shown in FIG. 2(e), a second metal layer 29 is formed on the first metal layer 26 to seal the hole 28, thereby forming a complementary metal oxide semi-microelectromechanical pressure sensor. The material of the second metal layer 29 can be, but not limited to, aluminum. The second metal layer 29 can be formed by evaporation or sputtering. As long as the second metal layer 29 has sufficient thickness, the hole 28 can be sealed. Assuming that the cross-sectional diameter of the hole 28 is 1 micron, the thickness of the second metal layer 29 is greater than or equal to 0.5 micron to seal the hole 28, because the second metal layer 29 will be formed on opposite inner sides of the hole 28 at the same time. Because the undoped polysilicon 240 isolates the doped polysilicon layer 22 and the second metal layer 29 , when the second metal layer 29 is recessed, the second metal layer 29 will not contact the doped polysilicon layer 22 to cause a short circuit event. However, if the same result can be achieved, it is not necessary to follow the order of the steps in the process shown in Figure 2(a) to Figure 2(e), and the steps shown in Figure 2(a) to Figure 2(e) do not have to be performed consecutively, that is, other steps can also be inserted therein.

Figure 3(a) to Figure 3(d) are cross-sectional views of the structure of each step in the second embodiment of manufacturing the complementary metal oxide semi-microelectromechanical pressure sensor of the present invention. Please refer to FIG. 3(a) to FIG. 3(d) below to introduce the second embodiment of the manufacturing method of the complementary metal oxide semi-microelectromechanical pressure sensor of the present invention. The steps in Fig. 3(a) to Fig. 3(b) are the same as the steps in Fig. 2(a) to Fig. 2(b) respectively, and will not be repeated here. As shown in FIG. 3(b) and FIG. 3(c), the mask 3 and the oxide insulating structure 250 directly above the inner region 230 are removed to expose the undoped polysilicon 240, and an opening 2510 communicating with the cavity 27 is formed directly above the inner region 230. The removal method of the oxide insulating structure 250 right above the inner region 230 may be, but not limited to, wet etching or etching with hydrogen fluoride vapor (HF vapor). Finally, as shown in FIG. 3(d), a sealing metal layer 29' is formed on the second oxide insulating layer 23, the patterned polysilicon layer 24 and the metal wiring layer 25 to seal the opening 2510, thereby forming a complementary metal oxide semi-microelectromechanical pressure sensor. Specifically, the sealing metal layer 29' is located on the oxide insulating structure 250 of the metal wiring layer 25, all the patterned metal layers 251 and all the metal vias 252. The material of the sealing metal layer 29' can be, but not limited to, aluminum. The sealing metal layer 29' can be formed by vapor deposition or sputtering. As long as the sealing metal layer 29' has a sufficient thickness, the opening 2510 can be sealed. Assuming that the cross-sectional diameter of the opening 2510 is 1 micron, the thickness of the sealing metal layer 29' is greater than or equal to 0.5 micron to seal the opening 2510, because the sealing metal layer 29' will be formed on opposite inner sides of the opening 2510 at the same time. Because the undoped polysilicon 240 is isolated from the doped polysilicon layer 22 and the sealing metal layer 29', when the sealing metal layer 29' is recessed, the sealing metal layer 29' will not contact the doped polysilicon layer 22 to cause a short circuit event. However, if the same result can be achieved, it is not necessary to follow the order of the steps in the process shown in Figure 3(a) to Figure 3(d), and the steps shown in Figure 3(a) to Figure 3(d) do not have to be performed consecutively, that is, other steps can also be inserted therein.

Figure 4(a) to Figure 4(c) are cross-sectional views of the structure of each step in the third embodiment of making a complementary metal oxide semi-microelectromechanical pressure sensor of the present invention. Please refer to FIG. 4(a) to FIG. 4(c) below to introduce the third embodiment of the manufacturing method of the complementary metal oxide semi-microelectromechanical pressure sensor of the present invention. First, as shown in FIG. 4(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, a patterned polysilicon layer 24, and a metal wiring layer 25 arranged in sequence from bottom to top. The metal wiring layer 25 is disposed on the second insulating oxide layer 23 and the patterned polysilicon layer 24 . The patterned polysilicon layer 24 may only include undoped polysilicon 240 or include undoped polysilicon 240 and doped polysilicon 241 . In the third embodiment, the patterned polysilicon layer 24 includes both undoped polysilicon 240 and doped polysilicon 241 as an example. The second insulating oxide layer 23 has an inner region 230 and an outer region 231 surrounding the inner region 230 . The undoped polysilicon 240 is located on the inner region 230, and the metal wiring layer 25 includes an oxide insulating structure 250 exposed outside and disposed on the undoped polysilicon 240, a plurality of patterned metal layers 251 and a circular metal via 252'. The annular metal through hole 252' is made of conductive material. The patterned metal layers 251 are embedded in the oxide insulating structure 250 , and all the patterned metal layers 251 are separated from each other and arranged sequentially from bottom to top. The lowermost patterned metal layer 251 is separated from the patterned polysilicon layer 24 , and the annular metal via 252 ′ penetrates through the oxide insulating structure 250 and all the patterned metal layers 251 , and surrounds the oxide insulating structure 250 directly above the inner region 230 . One end of the annular metal via 252' is located on the inner region 230 of the second insulating oxide layer 23, and the other end is exposed outside. The uppermost patterned metal layer 251 has an opening 2510 passing through it. The opening 2510 is located directly above the inner region 230 and filled with the oxide insulating structure 250 .

As shown in FIG. 4( b ), the oxide insulating structure 250 directly above the inner region 230 is removed to expose the undoped polysilicon 240 , and a cavity 27 communicating with the opening 2510 is formed directly above the inner region 230 . The removal method of the oxide insulating structure 250 right above the inner region 230 may be, but not limited to, wet etching or etching with hydrogen fluoride vapor (HF vapor).

As shown in FIG. 4(c), a sealing metal layer 29' is formed on the oxide insulating structure 250 and the uppermost patterned metal layer 251 to seal the opening 2510, thereby forming a complementary metal oxide semi-microelectromechanical pressure sensor. The material of the sealing metal layer 29' can be, but not limited to, aluminum. The sealing metal layer 29' can be formed by vapor deposition or sputtering. As long as the sealing metal layer 29' has a sufficient thickness, the opening 2510 can be sealed. Assuming that the cross-sectional diameter of the opening 2510 is 1 micron, the thickness of the sealing metal layer 29' is greater than or equal to 0.5 micron to seal the opening 2510, because the sealing metal layer 29' will be formed on opposite inner sides of the opening 2510 at the same time. Because the undoped polysilicon 240 is isolated from the doped polysilicon layer 22 and the sealing metal layer 29', when the sealing metal layer 29' is recessed, the sealing metal layer 29' will not contact the doped polysilicon layer 22 to cause a short circuit event. However, if the same result can be achieved, it is not necessary to follow the order of the steps in the process shown in Figure 4(a) to Figure 4(c), and the steps shown in Figure 4(a) to Figure 4(c) do not have to be performed consecutively, that is, other steps can also be inserted therein.

Fig. 5(a) to Fig. 5(b) are cross-sectional views of the structure of each step of an embodiment of manufacturing a complementary metal-oxide-semiconductor device of the present invention. The fabrication process of the CMOS device 2 of the present invention is described below, but the present invention is not limited thereto. First, as shown in FIG. 5( a ), a first insulating oxide layer 21 is formed on the semiconductor substrate 20 by thermal oxidation. Next, a doped polysilicon layer 22 is formed on the first insulating oxide layer 21 in conjunction with ion implantation. Next, a second insulating oxide layer 23 is formed on the doped polysilicon layer 22 by thermal oxidation. After the formation, a patterned polysilicon layer 24 is formed on the second oxide insulating layer 23 in cooperation with the patterning and etching process and the ion implantation method. Finally, as shown in FIG. 5( b ), the metal wiring layer 25 is formed on the patterned polysilicon layer 24 and the second oxide insulating layer 23 in conjunction with thermal oxidation, patterning and etching processes, and metal deposition.

According to the above-mentioned embodiment, the manufacturing method of the CMOS micro-electromechanical pressure sensor utilizes the low-cost standard CMOS process to form a patterned polysilicon layer, and uses the undoped polysilicon of the patterned polysilicon layer to isolate the doped polysilicon layer and the metal layer, so as to avoid short circuit between the doped polysilicon layer and the metal layer, and avoid the doped polysilicon layer from being etched.

The above is only a preferred embodiment of the present invention, and is not used to limit the scope of the present invention. Therefore, all equal changes and modifications made according to the shape, structure, characteristics and spirit described in the scope of the patent application of the present invention should be included in the scope of the patent application of the present invention.

10: Semiconductor substrate 12: Metal structure 2: Complementary metal oxide semiconductor device 20: Semiconductor substrate 21: The first oxide insulating layer 22: Doped polysilicon layer 23: Second oxide insulating layer 230: inner area 231: Outer area 24:Patterned polysilicon layer 240: Undoped polysilicon 241: Doped polysilicon 25: Metal wiring layer 250: oxidation insulation structure 251: Patterned metal layer 2510: opening 252: metal through hole 252': circular metal through hole 26: The first metal layer 27: Cavity 28: hole 29: Second metal layer 29': sealed metal layer 3: mask

Figure 1 is a cross-sectional view of the structure of a micro-electromechanical pressure sensor in the prior art. Figure 2(a) to Figure 2(e) are cross-sectional views of the structure of each step in the first embodiment of the complementary metal oxide semi-microelectromechanical pressure sensor of the present invention. Figure 3(a) to Figure 3(d) are cross-sectional views of the structure of each step in the second embodiment of manufacturing the complementary metal oxide semi-microelectromechanical pressure sensor of the present invention. Figure 4(a) to Figure 4(c) are cross-sectional views of the structure of each step in the third embodiment of making a complementary metal oxide semi-microelectromechanical pressure sensor of the present invention. Fig. 5(a) to Fig. 5(b) are cross-sectional views of the structure of each step of an embodiment of manufacturing a complementary metal-oxide-semiconductor device of the present invention.

2: Complementary metal oxide semiconductor device

20: Semiconductor substrate

21: The first oxide insulating layer

22: Doped polysilicon layer

23: Second oxide insulating layer

230: inner area

231: Outer area

24:Patterned polysilicon layer

240: Undoped polysilicon

241: Doped polysilicon

25: Metal wiring layer

250: oxidation insulation structure

251: Patterned metal layer

2510: opening

252: metal through hole

Claims (12)

A method for manufacturing a complementary metal oxide semi-microelectromechanical pressure sensor, comprising the following steps: A complementary metal-oxide-semiconductor device is provided, which includes a semiconductor substrate, a first insulating oxide layer, a doped polysilicon layer, a second insulating oxide layer, a patterned polysilicon layer, and a metal wiring layer arranged in sequence from bottom to top. The metal wiring layer is disposed on the second insulating oxide layer and the patterned polysilicon layer. The patterned polysilicon layer includes undoped polysilicon. , the metal wiring layer includes an oxide insulating structure exposed outside and disposed on the undoped polysilicon; forming a mask on the metal wiring layer directly above the inner region to remove the oxide insulating structure directly above the outer region, thereby exposing the second insulating oxide layer and the patterned polysilicon layer; removing the mask, and forming a first metal layer on the second insulating oxide layer, the patterned polysilicon layer and the metal wiring layer; removing the portion of the first metal layer and the oxide insulating structure directly above the inner region to expose the undoped polysilicon, and forming a cavity communicating with the hole directly above the inner region; and A second metal layer is formed on the first metal layer to seal the hole, so as to form a complementary metal oxide semi-microelectromechanical pressure sensor. The manufacturing method of the complementary metal oxide semi-micro-electromechanical pressure sensor as described in Claim 1, wherein the metal wiring layer further comprises a plurality of patterned metal layers and a plurality of metal vias, the plurality of patterned metal layers are embedded in the oxide insulating structure, the plurality of patterned metal layers are separated from each other, and are arranged sequentially from bottom to top, the lowermost patterned metal layer is separated from the patterned polysilicon layer, the plurality of metal via holes penetrate the oxide insulation structure and the plurality of patterned metal layers, and one end of each metal via hole is located on the second oxide insulation layer On the inner region, the other end is exposed to the outside, the uppermost patterned metal layer has an opening through itself, the opening is located directly above the inner region and filled with the oxide insulating structure, the mask is located on the uppermost patterned metal layer and the oxide insulating structure, the first metal layer is located on the oxide insulating structure, the plurality of patterned metal layers and the plurality of metal vias. The manufacturing method of the complementary metal oxide semi-microelectromechanical pressure sensor as described in Claim 1, wherein the removal method of the part of the first metal layer directly above the inner region and the oxide insulating structure is wet etching or etching with hydrogen fluoride vapor (HF vapor). The manufacturing method of the complementary metal oxide semi-microelectromechanical pressure sensor as described in Claim 1, wherein the material of the mask is a non-hydrofluoric acid etchable semiconductor material. A method for manufacturing a complementary metal oxide semi-microelectromechanical pressure sensor, comprising the following steps: A complementary metal-oxide-semiconductor device is provided, which includes a semiconductor substrate, a first insulating oxide layer, a doped polysilicon layer, a second insulating oxide layer, a patterned polysilicon layer, and a metal wiring layer arranged in sequence from bottom to top. The metal wiring layer is disposed on the second insulating oxide layer and the patterned polysilicon layer. The patterned polysilicon layer includes undoped polysilicon. , the metal wiring layer includes an oxide insulating structure exposed outside and disposed on the undoped polysilicon; forming a mask on the metal wiring layer directly above the inner region to remove the oxide insulating structure directly above the outer region, thereby exposing the second insulating oxide layer and the patterned polysilicon layer; removing the mask and the oxide insulating structure directly above the inner region to expose the undoped polysilicon, and forming an opening communicating with the cavity directly above the inner region; and A sealing metal layer is formed on the second oxide insulating layer, the patterned polysilicon layer and the metal wiring layer to seal the opening, thereby forming a complementary metal oxide semi-microelectromechanical pressure sensor. The manufacturing method of the complementary metal oxide semi-micro-electromechanical pressure sensor as described in claim 5, wherein the metal wiring layer further includes a plurality of patterned metal layers and a plurality of metal vias, the plurality of patterned metal layers are embedded in the oxide insulating structure, the plurality of patterned metal layers are separated from each other, and are arranged sequentially from bottom to top, the lowermost patterned metal layer is separated from the patterned polysilicon layer, the plurality of metal via holes penetrate the oxide insulation structure and the plurality of patterned metal layers, and one end of each metal via hole is located on the second oxide insulation layer On the inner region, the other end is exposed outside, the uppermost patterned metal layer has the opening through itself, the opening is filled with the oxide insulating structure, the mask is located on the uppermost patterned metal layer and the oxide insulating structure, the sealing metal layer is located on the oxide insulating structure, the plurality of patterned metal layers and the plurality of metal vias. The manufacturing method of the complementary metal oxide semi-microelectromechanical pressure sensor as described in Claim 5, wherein the removal method of the oxide insulating structure right above the inner region is wet etching or etching with hydrogen fluoride vapor (HF vapor). The manufacturing method of the complementary metal oxide semi-microelectromechanical pressure sensor as described in Claim 5, wherein the material of the mask is a non-hydrofluoric acid-etchable semiconductor material. A method for manufacturing a complementary metal oxide semi-microelectromechanical pressure sensor, comprising the following steps: A complementary metal-oxide-semiconductor device is provided, which includes a semiconductor substrate, a first insulating oxide layer, a doped polysilicon layer, a second insulating oxide layer, a patterned polysilicon layer, and a metal wiring layer arranged in sequence from bottom to top. The metal wiring layer is disposed on the second insulating oxide layer and the patterned polysilicon layer. The patterned polysilicon layer includes undoped polysilicon. The metal wiring layer includes an oxide insulating structure exposed on the undoped polysilicon, a plurality of patterned metal layers and an annular metal via hole, the plurality of patterned metal layers are embedded in the oxide insulating structure, the plurality of patterned metal layers are separated from each other, and arranged from bottom to top in sequence, the patterned metal layer at the bottom is separated from the patterned polysilicon layer, the annular metal via hole penetrates the oxide insulating structure and the plurality of patterned metal layers, and surrounds the oxide insulating structure located directly above the inner region. One end of the via hole is located on the inner region of the second oxide insulating layer, and the other end is exposed outside. The uppermost patterned metal layer has an opening through itself, and the opening is located directly above the inner region and filled with the oxide insulating structure; removing the oxide insulating structure directly above the inner region to expose the undoped polysilicon, and forming a cavity communicating with the opening directly above the inner region; and A sealing metal layer is formed on the oxidized insulating structure and the uppermost patterned metal layer to seal the opening, thereby forming a complementary metal oxide semi-microelectromechanical pressure sensor. The manufacturing method of the complementary metal oxide semi-microelectromechanical pressure sensor as described in Claim 9, wherein the removal method of the oxide insulating structure right above the inner region is wet etching or etching with hydrogen fluoride vapor (HF vapor). The manufacturing method of the complementary metal oxide semi-microelectromechanical pressure sensor as described in Claim 9, wherein the material of the oxide insulating structure is silicon dioxide. The manufacturing method of the complementary metal oxide semi-microelectromechanical pressure sensor as described in Claim 9, wherein the patterned polysilicon layer further includes doped polysilicon.

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