Glass substrate and capacitance-type pressure sensor using the same

Abstract

A glass substrate has a pair of main surfaces opposite to each other. Two island-shaped portions made of silicon are buried in the glass substrate. The tow island-shaped portions are exposed from the two main surfaces of the glass substrate, respectively. An electrode is formed on one main surface of the glass substrate so as to be electrically connected to one exposed portion of one island-shaped portion, and another electrode is formed thereon so as to be electrically connected to one exposed portion of the other island-shaped portion. Still another electrode is formed on the other main surface of the glass substrate so as to be electrically connected to the other exposed portion of the one island-shaped portion. A silicon substrate having a pressure sensing diaphragm is bonded to the other main surface of the glass substrate.

1 . A glass substrate manufacturing method comprising: 
 forming island-shaped portions on a surface of a silicon substrate;    pressing the island-shaped portions against a glass substrate while applying heat to bond the silicon substrate and the glass substrate; and    polishing the surface of the glass substrate to expose the island-shaped portions from the surface of the glass substrate.    
   
   
       2 . The glass substrate manufacturing method according to  claim 1 , 
 wherein the island-shaped portions are obtained by forming a mask on the surface of the silicon substrate and by performing a sand blast process on the silicon substrate having the mask formed thereon.    
   
   
       3 . The glass substrate manufacturing method according to  claim 1 , 
 wherein the island-shaped portions are formed by half-dicing the surface of the silicon substrate.    
   
   
       4 . A method of manufacturing a capacitance-type pressure sensor comprising: 
 manufacturing a glass substrate by the method according to  claim 1;     forming electrodes on the glass substrate so as to be electrically connected to the island-shaped portions that are exposed from the glass substrate, respectively; and    bonding, to the glass substrate, a silicon substrate having a pressure sensing diaphragm that is deformed by pressure to be measure such that the pressure sensing diaphragm is separated from the electrode at a predetermined gap.