Docstoc

Fabricating condenser microphone and condenser microphone

Document Sample
Fabricating condenser microphone and condenser microphone Powered By Docstoc
					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.
A method for fabricating a condenser microphone of the present invention is a method
for fabricating a condenser microphone including a fixed electrode, a vibrating
electrode and an air gap. A first semiconductor chip formed with the fixedelectrode is
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 method includes the steps of: forming the fixed electrode on afirst semiconductor
substrate, then forming a first interlayer dielectric to cover the fixed electrode and the
first semiconductor substrate and forming a plurality of metal spacers on the first
interlayer dielectric, thereby forming the firstsemiconductor chip; forming the
vibrating electrode on a second semiconductor substrate, then forming a second
interlayer dielectric to cover the vibrating electrode and the second semiconductor
substrate and forming a plurality of metal spacers on thesecond interlayer dielectric,
thereby forming the second semiconductor chip; and arranging the first and second
semiconductor chips so as to be opposed to each other and then metallically bonding
the first metal spacers to the associated second metalspacers. The 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.
According to the above-mentioned method, the first semiconductor chip formed with
the fixed electrode is metallically bonded to the second semiconductor chip formed
with the vibrating electrode using the metal spacers. Thus, a condensermicrophone
with excellent vibration resistance and reduced parasitic capacitance can be formed.
In this way, a small, high-power condenser microphone can be achieved with
excellent reliability.
In one preferred embodiment, the step of forming the first semiconductor chip may
further include the step of forming, on the first semiconductor substrate, a detection
circuit for detecting a signal from the condenser microphone. Furthermore,the
detection circuit preferably includes a MOS transistor, and the fixed electrode is
preferably formed simultaneously with a gate electrode of the MOS transistor.
A condenser microphone of the present invention includes a fixed electrode, a
vibrating electrode and an air gap. A first semiconductor chip formed with the fixed
electrode is bonded to a second semiconductor chip formed with the
vibratingelectrode with the air gap interposed between the first semiconductor chip
and the second semiconductor chip. The first semiconductor chip includes the fixed
electrode formed on a first semiconductor substrate, a first interlayer dielectric
covering thefixed electrode and the first semiconductor substrate, and a plurality of
metal spacers formed on the first interlayer dielectric. The second semiconductor chip
includes the vibrating electrode formed on a second semiconductor substrate, a
secondinterlayer dielectric covering the vibrating electrode and the second
semiconductor substrate, and a plurality of metal spacers formed on the second
interlayer dielectric. The first semiconductor chip and the second semiconductor chip
are metallicallybonded to each other using the first and second metal spacers. The air
gap is 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 andsecond metal spacers.
With this structure, the first semiconductor chip formed with the fixed electrode is
metallically bonded to the second semiconductor chip formed with the vibrating
electrode using the metal spacers. This enhances the vibration resistance of
thecondenser microphone and reduces the parasitic capacitance thereof. In this way, a
small, high-power condenser microphone can be achieved with excellent reliability.
In one preferred embodiment, the first semiconductor chip may further include a
detection circuit formed on the first semiconductor substrate to detect a signal from
the condenser microphone.
According to the condenser microphone of the present invention and the fabrication
method for the same, the first semiconductor chip formed with the fixed electrode is
metallically bonded to the second semiconductor chip formed with the
vibratingelectrode using the metal spacers. This enhances the vibration resistance of
the condenser microphone and reduces the parasitic capacitance thereof. In this way, a
small, high-power condenser microphone can be achieved with excellent reliability.

				
DOCUMENT INFO