Micro electro mechanical system (MEMS) microphone and fabrication method thereof
View Patent ↗Provided is a structure for improving performance of a micro electro mechanical system (MEMS) microphone by preventing deformation from occurring due to a residual stress and a package stress of a membrane and by decreasing membrane rigidity. A MEMS microphone according to the present disclosure includes a backplate formed on a substrate; an insulating layer formed on the substrate to surround the backplate; a membrane formed to be separate from above the backplate by a predetermined interval; a membrane supporting portion configured to connect the membrane to the substrate; and a buffering portion formed in a double spring structure between the membrane and the membrane supporting portion.
1. A micro electro mechanical system (MEMS) microphone, comprising:
a backplate formed on a substrate;
an insulating layer formed on the substrate to surround the backplate;
a membrane formed to be separate from above the backplate by a predetermined interval;
a membrane supporting portion configured to connect the membrane to the substrate; and
a buffering portion formed in a double spring structure between the membrane and the membrane supporting portion.
2. The MEMS microphone of claim 1 , wherein the buffering portion comprises:
an inner spring connected to the membrane;
an outer spring connected to the membrane supporting portion; and
a spacer connected between the inner spring and the outer spring.
3. The MEMS microphone of claim 2 , further comprising:
a protruding portion formed on the bottom surface of the spacer.
4. The MEMS microphone of claim 2 , wherein the outer spring has rigidity smaller than the inner spring.
5. The MEMS microphone of claim 3 , wherein an addition of a height of the protruding portion and a height of the insulating portion is a distance maintaining gap.
6. A MEMS microphone, comprising:
a substrate having a first insulating layer;
a membrane formed on the substrate;
a membrane supporting portion configured to fix the membrane to the substrate;
a buffering portion formed in a double spring structure between the membrane and the membrane supporting portion; and
a backplate formed to be separate from above the membrane by a predetermined interval.
7. The MEMS microphone of claim 6 , wherein the buffering portion comprises:
an inner spring connected to the membrane;
an outer spring connected to the membrane supporting portion; and
a spacer connected between the inner spring and the outer spring.
8. The MEMS microphone of claim 7 , further comprising:
a second insulating layer attached on the bottom surface of the backplate; and
a protruding portion formed on the top surface of the spacer to face the second insulating layer.
9. The MEMS microphone of claim 7 , wherein the outer spring has rigidity smaller than the inner spring.
10. The MEMS microphone of claim 8 , wherein an addition of a height of the protruding portion and a height of the second insulating portion is a distance maintaining gap.
11. The MEMS microphone of claim 6 , further comprising:
a backplate supporting portion configured to fix the backplate to the substrate.