Force sensor and manufacture method thereof

Abstract

A force sensor comprises a first substrate, a second substrate, a third substrate, and a package body. The first substrate includes a fixed electrode, at least one first conductive contact, and at least one second conductive contact. The second substrate is disposed on the first substrate and electrically connected to the first conductive contact of the first substrate. The second substrate includes a micro-electro-mechanical system (MEMS) element corresponding to the fixed electrode. The third substrate is disposed on the second substrate and includes a pillar connected to the MEMS element. The package body covers the third substrate. The foregoing force sensor has better reliability.

What is claimed is: 
     
         1 . A method for manufacturing a force sensor, comprising:
 providing a third substrate and defining at least one first connection member and a pillar in the third substrate;   providing a second substrate including a first surface and a second surface opposite to the first substrate;   facing the second surface to the third substrate and joining the second substrate to the first connection member and the pillar of the third substrate;   defining at least one second connection member in the first surface of the second substrate;   defining a MEMS element in the second substrate, wherein the MEMS element is connected with the pillar;   providing a first substrate including a fixed electrode, at least one first conductive contact and at least one second conductive contact;   joining the first substrate to the second substrate, wherein the at least one first conductive contact is electrically connected with the at least one second connection member, and wherein the MEMS element is corresponding to the fixed electrode; and   using a package body to cover the first substrate, the second substrate and the third substrate.   
     
     
         2 . The method for manufacturing a force sensor according to  claim 1  further comprising thinning the third substrate. 
     
     
         3 . The method for manufacturing a force sensor according to  claim 1  further comprising thinning the second substrate. 
     
     
         4 . The method for manufacturing a force sensor according to  claim 1  further comprising forming a conductive material on the second connection member. 
     
     
         5 . The method for manufacturing a force sensor according to  claim 1 , wherein the first substrate includes at least one reference electrode, and the second substrate includes at least one reference element corresponding to the reference electrode. 
     
     
         6 . The method for manufacturing a force sensor according to  claim 5 , wherein the at least one reference element is a fixed element. 
     
     
         7 . The method for manufacturing a force sensor according to  claim 5 , wherein the at least one reference element is a movable element. 
     
     
         8 . The method for manufacturing a force sensor according to  claim 1 , wherein the first substrate includes a complementary metal oxide semiconductor (CMOS) substrate. 
     
     
         9 . The method for manufacturing a force sensor according to  claim 1 , wherein the first substrate includes an application specific integrated circuit (ASIC). 
     
     
         10 . The method for manufacturing a force sensor according to  claim 1  further comprising:
 disposing the first substrate on an ASIC chip or disposing the first substrate beside the ASIC chip on the same plane; and 
 using a lead to electrically connect the at least one second conductive contact with ASIC chip. 
 
     
     
         11 . The method for manufacturing a force sensor according to  claim 1 , wherein the package body includes a protrusion corresponding to the MEMS element. 
     
     
         12 . The method for manufacturing a force sensor according to  claim 1  further comprising disposing a protrudent member on the package body, wherein the protrudent member includes a bump corresponding to the MEMS element. 
     
     
         13 . The method for manufacturing a force sensor according to  claim 12 , wherein a top surface of the bump is a plane or a curved surface. 
     
     
         14 . The method for manufacturing a force sensor according to  claim 12 , wherein the bump is made of a metallic material or a polymeric material. 
     
     
         15 . The method for manufacturing a force sensor according to  claim 12 , wherein the protrudent member includes a plate disposed between the bump and the package body or disposed above the bump. 
     
     
         16 . The method for manufacturing a force sensor according to  claim 15 , wherein a projection area of the plate is smaller than or equal to an area of the third substrate. 
     
     
         17 . The method for manufacturing a force sensor according to  claim 15 , wherein the plate is disposed between the bump and the package body and covers the package body. 
     
     
         18 . The method for manufacturing a force sensor according to  claim 15 , wherein the plate is disposed above the bump and includes at least one connection leg connected with the package body.