Mems pressure sensor and method for forming the same

Abstract

Provided are a MEMS pressure sensor and a method for forming the same. The method includes: preparing a first substrate, where the first substrate includes a first surface and a second surface opposite to the first surface; preparing a second substrate, where the second substrate includes a third surface and a fourth surface opposite to the third surface; bonding the first surface of the first substrate and the third surface of the second substrate with each other and forming a cavity between the first substrate and the pressure sensing region of the second substrate; removing the second base to form a fifth surface opposite to the third surface of the second substrate; and forming a first conductive plug passing through the second substrate from the side of the fifth surface of the second substrate to the at least one conductive layer.

1 . A method for forming a Micro-Electro Mechanical System (MEMS) pressure sensor, comprising:
 preparing a first substrate, wherein the first substrate comprises a first surface and a second surface opposite to the first surface, and the first substrate comprises at least one conductive layer arranged on the side of the first surface of the first substrate;   preparing a second substrate, wherein the second substrate comprises a third surface and a fourth surface opposite to the third surface, the second substrate comprises a second base and a pressure-sensing electrode arranged on or above the second base, the second substrate comprises a pressure sensing region in which the pressure-sensing electrode is arranged, and the pressure-sensing electrode is arranged on the side of the third surface of the second substrate;   bonding the first surface of the first substrate and the third surface of the second substrate with each other;   forming a cavity between the first substrate and the pressure sensing region of the second substrate;   removing the second base to form a fifth surface opposite to the third surface of the second substrate; and   forming a first conductive plug passing through the second substrate from the side of the fifth surface of the second substrate to the at least one conductive layer, wherein the first conductive plug is used to electrically connect the conductive layer to the pressure-sensing electrode.   
     
     
         2 . The method for forming the MEMS pressure sensor according to  claim 1 , wherein the second substrate further comprises a fixed electrode corresponding to the pressure-sensing electrode, and the cavity is formed between the pressure-sensing electrode and the fixed electrode. 
     
     
         3 . The method for forming the MEMS pressure sensor according to  claim 1 , wherein the first substrate further comprises a fixed electrode arranged on the side of the first surface of the first substrate; when the first surface of the first substrate and the third surface of the second substrate are bonded with each other, the fixed electrode corresponds to the pressure-sensing electrode and the cavity is formed between the pressure-sensing electrode and the fixed electrode. 
     
     
         4 . The method for forming the MEMS pressure sensor according to  claim 3 , wherein the forming the cavity comprises: before the first surface of the first substrate and the third surface of the second substrate are bonded with each other, forming a first opening on the side of the third surface of the second substrate or on the side of the first surface of the first substrate, or, forming the first opening on both the side of the first surface of the first substrate and the side of the third surface of the second substrate, with a location of the first opening corresponding to a location of the pressure sensing region. 
     
     
         5 . The method for forming the MEMS pressure sensor according to  claim 1 , wherein the first substrate further comprises a circuit. 
     
     
         6 . The method for forming the MEMS pressure sensor according to  claim 1 , wherein the preparing the second substrate comprises: preparing a semiconductor-on-insulator substrate, wherein the semiconductor-on-insulator substrate comprises a base, an insulating layer arranged on a surface of the base and a semiconductor layer arranged on a surface of the insulating layer; and forming a pressure-sensing electrode in the semiconductor layer, with the base being the second base. 
     
     
         7 . The method for forming the MEMS pressure sensor according to  claim 1 , wherein the second substrate further comprises a second coupling layer arranged on the side of the third surface; or, the first substrate comprises a first coupling layer arranged on the side of the first surface; or, the second substrate further comprises a second coupling layer arranged on the side of the third surface and the first substrate comprises a first coupling layer arranged on the side of the first surface. 
     
     
         8 . The method for forming the MEMS pressure sensor according to  claim 7 , wherein at least one of the first coupling layer and the second coupling layer is comprised of an insulating material. 
     
     
         9 . The method for forming the MEMS pressure sensor according to  claim 7 , wherein the first surface of the first substrate and the third surface of the second substrate are bonded with each other by an adhesive bonding process, and the first coupling layer or the second coupling layer is an adhesive bonding layer which is comprised of an insulating material, a semiconductor material, a metal material or an organic material. 
     
     
         10 . The method for forming the MEMS pressure sensor according to  claim 1 , wherein the first surface of the first substrate and the third surface of the second substrate are bonded with each other by a direct-bonding process. 
     
     
         11 . The method for forming the MEMS pressure sensor according to  claim 1 , wherein the first substrate further comprises a self-test electrode, with a location of the self-test electrode corresponding to a location of the pressure sensing region after the first surface of the first substrate and the third surface of the second substrate are bonded with each other. 
     
     
         12 . The method for forming the MEMS pressure sensor according to  claim 1 , wherein the second substrate further comprises a reference unit region, a cavity is formed between the first substrate and the reference unit region of the second substrate when the first surface of the first substrate and the third surface of the second substrate are bonded with each other, and a deformation on a portion of the second substrate corresponding to the reference unit region is less than a deformation on a portion of the second substrate corresponding to the pressure sensing region under a same external pressure. 
     
     
         13 . The method for forming the MEMS pressure sensor according to  claim 1 , further comprising: forming a second opening passing through the first substrate, wherein a location of the second opening corresponds to a location of the pressure sensing region of the second substrate after the first surface of the first substrate and the third surface of the second substrate are bonded with each other. 
     
     
         14 . The method for forming the MEMS pressure sensor according to  claim 1 , further comprising: forming a fourth conductive plug passing through the first substrate from the side of the second surface of the first substrate to the at least one conductive layer. 
     
     
         15 . A method for forming a Micro-Electro Mechanical System (MEMS) pressure sensor, comprising:
 preparing a first substrate, wherein the first substrate comprises a first surface and a second surface opposite to the first surface, and the first substrate comprises at least one conductive layer arranged on the side of the first surface of the first substrate;   preparing a second substrate, wherein the second substrate comprises a third surface and a fourth surface opposite to the third surface, the second substrate comprises a second base and a pressure-sensing electrode arranged on or above or in the second base, the second substrate comprises a pressure sensing region in which the pressure-sensing electrode is arranged, and the pressure-sensing electrode is arranged on the side of the third surface of the second substrate;   bonding the first surface of the first substrate and the third surface of the second substrate with each other;   forming a cavity between the first substrate and the pressure sensing region of the second substrate;   thinning the second substrate from the fourth surface of the second substrate by partially removing the second base, to form a fifth surface opposite to the third surface of the second substrate; and   forming a first conductive plug passing through the second substrate from the side of the fifth surface of the second substrate to the at least one conductive layer, wherein the first conductive plug is used to electrically connect the conductive layer to the pressure-sensing electrode.   
     
     
         16 . The method for forming the MEMS pressure sensor according to  claim 15 , wherein the second substrate further comprises a fixed electrode corresponding to the pressure-sensing electrode and the cavity is formed between the pressure-sensing electrode and the fixed electrode. 
     
     
         17 . The method for forming the MEMS pressure sensor according to  claim 15 , wherein the first substrate further comprises a fixed electrode arranged on the side of the first surface of the first substrate; when the first surface of the first substrate and the third surface of the second substrate are bonded with each other, the fixed electrode corresponds to the pressure-sensing electrode and the cavity is formed between the pressure-sensing electrode and the fixed electrode. 
     
     
         18 . The method for forming the MEMS pressure sensor according to  claim 17 , wherein the forming the cavity comprises: before the first surface of the first substrate and the third surface of the second substrate are bonded with each other, forming a first opening on the side of the third surface of the second substrate or on the side of the first surface of the first substrate, or, forming the first opening on both the side of the first surface of the first substrate and the side of the third surface of the second substrate, with a location of the first opening corresponding to a location of the pressure sensing region. 
     
     
         19 . The method for forming the MEMS pressure sensor according to  claim 15 , wherein the first substrate further comprises a circuit. 
     
     
         20 . The method for forming the MEMS pressure sensor according to  claim 15 , wherein a third opening is formed in the second substrate after the second substrate is thinned from the fourth surface, with a location of the third opening corresponding to a location of the pressure sensing region. 
     
     
         21 . The method for forming the MEMS pressure sensor according to  claim 15 , wherein the preparing the second substrate comprises: preparing a semiconductor-on-insulator substrate, wherein the semiconductor-on-insulator substrate comprises a base, an insulating layer arranged on a surface of the base and a semiconductor layer arranged on a surface of the insulating layer; and forming a pressure-sensing electrode in the semiconductor layer, with the base being the second base. 
     
     
         22 . The method for forming the MEMS pressure sensor according to  claim 15 , wherein the second substrate further comprises a second coupling layer arranged on the side of the third surface; or, the first substrate comprises a first coupling layer arranged on the side of the first surface; or, the second substrate further comprises a second coupling layer arranged on the side of the third surface and the first substrate comprises a first coupling layer arranged on the side of the first surface. 
     
     
         23 . The method for forming the MEMS pressure sensor according to  claim 22 , wherein at least one of the first coupling layer and the second coupling layer is comprised of an insulating material. 
     
     
         24 . The method for forming the MEMS pressure sensor according to  claim 22 , wherein the first surface of the first substrate and the third surface of the second substrate are bonded with each other by an adhesive bonding process, and the first coupling layer or the second coupling layer is an adhesive bonding layer which is comprised of an insulating material, a semiconductor material, a metal material or an organic material. 
     
     
         25 . The method for forming the MEMS pressure sensor according to  claim 15 , wherein the first surface of the first substrate and the third surface of the second substrate are bonded with each other by a direct-bonding process. 
     
     
         26 . The method for forming the MEMS pressure sensor according to  claim 15 , wherein the first substrate further comprises a self-test electrode, with a location of the self-test electrode corresponding to a location of the pressure sensing region after the first surface of the first substrate and the third surface of the second substrate are bonded with each other. 
     
     
         27 . The method for forming the MEMS pressure sensor according to  claim 15 , wherein the second substrate further comprises a reference unit region, a cavity is formed between the first substrate and the reference unit region of the second substrate when the first surface of the first substrate and the third surface of the second substrate are bonded with each other, and a deformation on a portion of the second substrate corresponding to the reference unit region is less than a deformation on a portion of the second substrate corresponding to the pressure sensing region under a same external pressure. 
     
     
         28 . The method for forming the MEMS pressure sensor according to  claim 15 , further comprising: forming a second opening passing through the first substrate, wherein a location of the second opening corresponds to a location of the pressure sensing region of the second substrate after the first surface of the first substrate and the third surface of the second substrate are bonded with each other. 
     
     
         29 . The method for forming the MEMS pressure sensor according to  claim 15 , further comprising: forming at least one fifth through hole passing through the second base, on the side of the fifth surface of the second substrate, with a location of the fifth through hole corresponding to a location of the pressure sensing region. 
     
     
         30 . The method for forming the MEMS pressure sensor according to  claim 15 , further comprising: forming a fourth conductive plug passing through the first substrate from the side of the second surface of the first substrate to the at least one conductive layer. 
     
     
         31 . A Micro-Electro Mechanical System (MEMS) pressure sensor, comprising:
 a first substrate, wherein the first substrate comprises a first surface and a second surface opposite to the first substrate, and the first substrate comprises at least one conductive layer arranged on the side of the first surface of the first substrate;   a second substrate, wherein the second substrate comprises a third surface and a fifth surface opposite to the third surface, the second substrate comprises a pressure-sensing electrode, and the second substrate comprises a pressure sensing region in which the pressure-sensing electrode is arranged, the first surface of the first substrate and the third surface of the second substrate are bonded with each other;   a cavity formed between the first substrate and the pressure sensing region of the second substrate; and   a first conductive plug passing through the second substrate from the side of the fifth surface of the second substrate to the at least one conductive layer, wherein the first conductive plug is used to electrically connect the conductive layer to the pressure-sensing electrode.   
     
     
         32 . The MEMS pressure sensor according to  claim 31 , wherein the second substrate further comprises a fixed electrode corresponding to the pressure-sensing electrode and the cavity is formed between the pressure-sensing electrode and the fixed electrode. 
     
     
         33 . The MEMS pressure sensor according to  claim 31 , wherein the first substrate further comprises a fixed electrode arranged on the side of the first surface of the first substrate; the fixed electrode corresponds to the pressure-sensing electrode and the cavity is formed between the pressure-sensing electrode and the fixed electrode. 
     
     
         34 . The MEMS pressure sensor according to  claim 31 , wherein the first substrate further comprises a circuit. 
     
     
         35 . The MEMS pressure sensor according to  claim 31 , wherein the second substrate further comprises a second coupling layer arranged on the side of the third surface; or, the first substrate comprises a first coupling layer arranged on the side of the first surface; or, the second substrate further comprises a second coupling layer arranged on the side of the third surface and the first substrate comprises a first coupling layer arranged on the side of the first surface. 
     
     
         36 . The MEMS pressure sensor according to  claim 35 , wherein at least one of the first coupling layer and the second coupling layer is comprised of an insulating material. 
     
     
         37 . The MEMS pressure sensor according to  claim 35 , wherein the first coupling layer or the second coupling layer is an adhesive bonding layer which is comprised of an insulating material, a semiconductor material, a metal material or an organic material. 
     
     
         38 . The MEMS pressure sensor according to  claim 35 , wherein the first coupling layer is a bonding layer; or, the second coupling layer is a bonding layer; or, the first coupling layer and the second coupling layer are bonding layers. 
     
     
         39 . The MEMS pressure sensor according to  claim 31 , wherein the first substrate further comprises a self-test electrode, with a location of the self-test electrode corresponding to a location of the pressure sensing region of the second substrate. 
     
     
         40 . The MEMS pressure sensor according to  claim 31 , wherein the second substrate further comprises a reference unit region, a cavity is formed between the first substrate and the reference unit region of the second substrate, and a deformation on a portion of the second substrate corresponding to the reference unit region is less than a deformation on a portion of the second substrate corresponding to the pressure sensing region. 
     
     
         41 . The MEMS pressure sensor according to  claim 31 , further comprising: a second opening passing through the first substrate, with a location of the second opening corresponding to a location of the pressure sensing region of the second substrate. 
     
     
         42 . The MEMS pressure sensor according to  claim 31 , further comprising: a fourth conductive plug passing through the first substrate from the side of the second surface of the first substrate to the at least one conductive layer. 
     
     
         43 . A Micro-Electro Mechanical System (MEMS) pressure sensor, comprising:
 a first substrate, wherein the first substrate comprises a first surface and a second surface opposite to the first surface, and the first substrate comprises at least one conductive layer arranged on the side of the first surface of the first substrate;   a second substrate, wherein the second substrate comprises a third surface and a fifth surface opposite to the third surface, the second substrate comprises a second base and a pressure-sensing electrode arranged on or above or in the second base, and the second substrate comprises a pressure sensing region in which the pressure-sensing electrode is arranged, the first surface of the first substrate and the third surface of the second substrate are bonded with each other;   a cavity formed between the first substrate and the pressure sensing region of the second substrate; and   a first conductive plug passing through the second substrate from the side of the fifth surface of the second substrate to the at least one conductive layer, wherein the first conductive plug is used to electrically connect the conductive layer to the pressure-sensing electrode.   
     
     
         44 . The MEMS pressure sensor according to  claim 43 , wherein the second substrate further comprises a fixed electrode corresponding to the pressure-sensing electrode and the cavity is formed between the pressure-sensing electrode and the fixed electrode. 
     
     
         45 . The MEMS pressure sensor according to  claim 43 , wherein the first substrate further comprises a fixed electrode arranged on the side of the first surface of the first substrate; the fixed electrode corresponds to the pressure-sensing electrode and the cavity is formed between the pressure-sensing electrode and the fixed electrode. 
     
     
         46 . The MEMS pressure sensor according to  claim 43 , wherein the first substrate further comprises a circuit. 
     
     
         47 . The MEMS pressure sensor according to  claim 43 , wherein a third opening is formed in the second substrate, with a location of the third opening corresponding to a location of the pressure sensing region. 
     
     
         48 . The MEMS pressure sensor according to  claim 43 , wherein the second substrate further comprises a second coupling layer arranged on the side of the third surface; or, the first substrate comprises a first coupling layer arranged on the side of the first surface; or, the second substrate further comprises a second coupling layer arranged on the side of the third surface and the first substrate comprises a first coupling layer arranged on the side of the first surface. 
     
     
         49 . The MEMS pressure sensor according to  claim 48 , wherein at least one of the first coupling layer and the second coupling layer is comprised of an insulating material. 
     
     
         50 . The MEMS pressure sensor according to  claim 48 , wherein the first coupling layer or the second coupling layer is an adhesive bonding layer which is comprised of an insulating material, a semiconductor material, a metal material or an organic material. 
     
     
         51 . The MEMS pressure sensor according to  claim 48 , wherein the first coupling layer is a bonding layer; or, the second coupling layer is a bonding layer; or, the first coupling layer and the second coupling layer are bonding layers. 
     
     
         52 . The MEMS pressure sensor according to  claim 43 , wherein the first substrate further comprises a self-test electrode, with a location of the self-test electrode corresponding to a location of the pressure sensing region of the second substrate. 
     
     
         53 . The MEMS pressure sensor according to  claim 43 , wherein the second substrate further comprises a reference unit region, a cavity is formed between the first substrate and the reference unit region of the second substrate, and a deformation on a portion of the second substrate corresponding to the reference unit region is less than a deformation on a portion of the second substrate corresponding to the pressure sensing region. 
     
     
         54 . The MEMS pressure sensor according to  claim 43 , wherein a second opening passing through the first substrate is formed, with a location of the second opening corresponding to a location of the pressure sensing region of the second substrate. 
     
     
         55 . The MEMS pressure sensor according to  claim 43 , further comprising: at least one fifth through hole arranged on the side of the fifth surface of the second substrate and passing through the second base, with a location of the fifth through hole corresponding to a location of the pressure sensing region. 
     
     
         56 . The MEMS pressure sensor according to  claim 43 , further comprising: a fourth conductive plug passing through the first substrate from the side of the second surface of the first substrate to the at least one conductive layer.