Solid state silicon-based condenser microphone

Abstract

A solid state silicon-based condenser microphone comprising a silicon transducer chip ( 1 ). The transducer chip includes a backplate ( 13 ) and a diaphragm ( 12 ) arranged substantially parallel to each other with a small air gap in between, thereby forming an electrical capacitor. The diaphragm ( 12 ) is movable relative to the backplate ( 13 ) in response to incident sound. An integrated electronic circuit chip ( 3 ) or ASIC is electrically coupled to the transducer chip ( 1 ). An intermediate layer ( 2 ) fixes the transducer chip ( 1 ) to the integrated electronic circuit chip ( 3 ) with the transducer chip ( 1 ) on a first side of the intermediate layer ( 2 ) and the integrated electronic circuit chip ( 3 ) on a second side of the intermediate layer ( 2 ) opposite the first side. The intermediate layer ( 2 ) has a sound inlet ( 4 ) on the same side as the ASIC giving access of sound to the diaphragm.

1. A solid state silicon-based condenser microphone comprising a silicon transducer chip ( 1 ) including a backplate ( 13 ) and a diaphragm ( 12 ) arranged substantially parallel to each other, thereby forming an electrical capacitor, the diaphragm ( 12 ) being movable relative to the backplate ( 13 ) in response to incident sound, an integrated electronic circuit chip ( 3 ) electrically coupled to the transducer chip ( 1 ), an intermediate layer ( 2 ) fixing the transducer chip ( 1 ) to the integrated electronic circuit chip ( 3 ) in a spaced relationship, with the transducer chip ( 1 ) on a first side of the intermediate layer ( 2 ) and the integrated electronic circuit chip ( 3 ) on a second side of the intermediate layer ( 2 ) opposite the first side, the intermediate layer ( 2 ) having a first through going opening ( 4 ,  10 ) between its first side and its second side giving access of sound to the diaphragm. 
     
     
       2. A condenser microphone according to  claim 1  wherein the intermediate layer ( 2 ) on a surface thereof has electrical conductors ( 14 ) electrically connecting the transducer chip ( 1 ) to the integrated circuit chip ( 3 ). 
     
     
       3. A condenser microphone according to  claim 2  wherein the intermediate layer ( 2 ) has a second through going opening ( 18 ) with a surface on which the electrical conductors ( 14 ) electrically connecting the transducer chip ( 1 ) to the integrated circuit chip ( 3 ) are situated. 
     
     
       4. A condenser microphone according to  claim 1  wherein the opening ( 4 ) in the intermediate layer is covered with a film ( 5 ) sealing the opening ( 4 ) on the second side of the intermediate layer ( 2 ). 
     
     
       5. A condenser microphone according to  claim 1  wherein a cavity ( 11 ) is provided in the transducer chip ( 1 ) on a side of the diaphragm ( 12 ) opposite the intermediate layer ( 2 ). 
     
     
       6. A condenser microphone according to  claim 5  wherein the cavity ( 11 ) is a closed cavity. 
     
     
       7. A condenser microphone according to  claim 2  wherein the integrated electronic circuit chip ( 3 ) has a surface including electronic circuits with said surface facing the intermediate layer ( 2 ). 
     
     
       8. A condenser microphone according to  claim 1  wherein the intermediate layer ( 2 ) is a silicon-based chip. 
     
     
       9. A silicon-based electroacoustic transducer, comprising:
 a silicon-based transducer chip for transducing between acoustic signals and electrical signals, wherein said silicon-based transducer chip includes a backplate and a diaphragm;   a silicon-based integrated electronic circuit chip; and   an intermediate element secured to said silicon-based transducer chip and to said integrated electronic circuit chip, said intermediate element including an electrical conductor electrically coupling said integrated electronic circuit chip and said transducer chip, said electrical signals being transmitted along said electrical conductor.    
     
     
       10. The silicon-based electroacoustic transducer of claim 9, wherein said silicon-based integrated electronic circuit chip is an ASIC chip.  
     
     
       11. The silicon-based electroacoustic transducer of claim 9, wherein said silicon-based integrated electronic circuit chip is flip-chip mounted to said intermediate element.  
     
     
       12. The silicon-based electroacoustic transducer of claim 9, wherein said intermediate element includes a feed-through, said feed-through including a feed-through conductor leading to said silicon-based integrated electronic circuit chip.  
     
     
       13. The transducer of claim 9, wherein the intermediate element has a first surface and a second surface opposing said first surface, said silicon-based transducer being mounted to said first surface, said intermediate element further including an acoustic port on said second surface leading to an acoustic passage extending to said first surface of said intermediate element, said acoustic passage for transmitting said acoustic signals to said transducer chip mounted on said first surface of said intermediate element; and
 a filter adjacent to said acoustic port for preventing contamination of said acoustic passage.    
     
     
       14. The transducer of claim 9, wherein the integrated electronic circuit chip has an integrated circuit on a surface thereof.