Method for fabricating condenser microphone and condenser microphone
A first semiconductor chip includes a fixed electrode formed on a first semiconductor substrate and a plurality of first metal spacers formed on a first interlayer dielectric. A second semiconductor chip includes a vibrating electrode formed on a second semiconductor substrate and a plurality of second metal spacers formed on a second interlayer dielectric. The first and second semiconductor chips are metallically bonded to each other using the first and second metal spacers. An air gap is formed in a region of the condenser microphone located between the first semiconductor chip and the second semiconductor chip except bonded regions of the first and second metal spacers.
1. A condenser microphone including a fixed electrode, a vibrating electrode and an air gap, a first semiconductor chip formed with the fixed electrode being bonded to a second semiconductor chip formed with the vibrating electrode with the air gap interposed between the first semiconductor chip and the second semiconductor chip,
the first semiconductor chip comprising the fixed electrode formed on a first semiconductor substrate, a first interlayer dielectric covering the fixed electrode and the first semiconductor substrate, and a plurality of first metal spacers formed on the first interlayer dielectric,
the second semiconductor chip comprising the vibrating electrode formed on a second semiconductor substrate, a second interlayer dielectric covering the vibrating electrode and the second semiconductor substrate, and a plurality of second metal spacers formed on the second interlayer dielectric,
the first semiconductor chip and the second semiconductor chip being metallically bonded to each other using the first and second metal spacers, and
the air gap being formed in a region of the condenser microphone located between the first interlayer dielectric and the second interlayer dielectric except bonded regions of the first and second metal spacers.
2. The condenser microphone of claim 1 , wherein
the first semiconductor chip further includes a detection circuit formed on the first semiconductor substrate to detect a signal from the condenser microphone.
3. The condenser microphone of any one of claims 1 and 2 , wherein
the first semiconductor chip further includes a plurality of first contact plugs formed in the first interlayer dielectric,
the second semiconductor chip further includes a plurality of second contact plugs formed in the second interlayer dielectric and a plurality of electrode pads formed on the second interlayer dielectric, and
the fixed electrode is electrically connected to associated one of the electrode pads through associated one of the first contact plugs, associated one of the first metal spacers, one of the second metal spacers bonded to the associated first metal spacer, and associated one of the second contact plugs.
4. The condenser microphone of claim 3 , wherein
the detection circuit is electrically connected to associated one of the electrode pads through associated one of the first contact plugs, associated one of the first metal spacers, one of the second metal spacers bonded to the associated first metal spacer, and associated one of the second contact plugs.