Piezoelectric devices mounted on integrated circuit chip

Abstract

The invention is a filter circuit that includes an electromechanical resonator that is mounted directly to the surface of a silicon integrated circuit, rather than being mounted as a surface mounted or leaded filter can on a circuit board. This filter system allows the integrated circuit electronic package to be significantly smaller than when a conventional electromechanical resonator package is used. The electromechanical resonator may be protected during processing and during use with a protective cover that is made of a material such as titanium. The protective cover is attached to the integrated circuit chip.

What is claimed is:  
     
         1 . An integrated circuit filter system comprising: 
 an integrated circuit chip containing an electronic circuit; and    at least one electromechanical resonator mounted to and supported by said integrated circuit chip and electrically coupled to said electronic circuit.    
     
     
         2 . The integrated circuit filter system according to  claim 1  wherein said electromechanical resonator is mounted to said integrated circuit chip by at least one mounting pad.  
     
     
         3 . The integrated circuit filter system according to  claim 2  wherein said at least one mounting pad is a gold bump.  
     
     
         4 . The integrated circuit filter system according to  claim 2  wherein said at least one mounting pad is electrically conductive.  
     
     
         5 . The integrated circuit filter system according to  claim 2  wherein said at least one mounting pad is comprised of an electrically conductive epoxy.  
     
     
         6 . The integrated circuit oscillator system according to  claim 1  wherein said at least one electromechanical resonator is comprised of quartz.  
     
     
         7 . The integrated circuit filter system according to  claim 1  wherein said integrated circuit chip is comprised of silicon.  
     
     
         8 . The integrated circuit filter system according to  claim 1  wherein said electronic circuit is at least partially comprised of an oscillator circuit.  
     
     
         9 . The integrated circuit filter system according to  claim 1  wherein said integrated circuit chip has a top surface and a bottom surface and at least one electromechanical resonator is mounted on said top surface.  
     
     
         10 . The integrated circuit filter system according to  claim 1  wherein said integrated circuit chip has a top surface and a bottom surface and at least one electromechanical resonator is mounted on said top surface of said integrated circuit chip and a second electromechanical resonator is mounted on said bottom surface of said integrated circuit chip.  
     
     
         11 . The integrated circuit filter system according to  claim 1  wherein said integrated circuit chip is comprised of a stack of at least two integrated circuit chips.  
     
     
         12 . The integrated circuit filter system according to  claim 11  wherein said at least two integrated circuit chips are oriented to define a cavity therebetween and said at least one electromechanical resonator is mounted in said cavity.  
     
     
         13 . The integrated circuit filter system according to  claim 1  wherein said at least one electromechanical resonator is under a protective cover.  
     
     
         14 . The integrated circuit filter system according to  claim 13  wherein said protective cover is comprised of titanium.  
     
     
         15 . A method of forming a filter circuit on an integrated circuit chip comprising the steps of: 
 selecting an integrated circuit chip,    selecting at least one electromechanical resonator,    forming at least one mounting pad on at least one surface of said integrated circuit chip, and    attaching at least one electromechanical resonator to said at least one mounting pad.    
     
     
         16 . The method of forming a filter system according to  claim 15  wherein said step of forming at least one mounting pad is forming said pad directly on said at least one surface of said integrated circuit chip.  
     
     
         17 . The method of forming a filter system according to  claim 15  wherein said step of attaching said electromechanical resonator is adhesive bonding with an electrically conductive adhesive.  
     
     
         18 . The method of forming a filter system according to  claim 15  further comprising the step of attaching a protective cover over said electromechanical resonator.  
     
     
         19 . An integrated circuit filter system for an implantable electronic device, that is implantable in living tissue, which may be a microstimulator or a microsensor having an axial dimension of less than 60 mm and a lateral dimension of less than 6 mm, wherein said electronic device includes at least two electrodes for delivering electrical signals between said electronic device and living tissue, said system comprising: 
 an integrated circuit chip containing an electronic circuit; and    at least one electromechanical resonator mounted to and supported by said integrated circuit chip and electrically coupled to said electronic circuit.