Method of fabricating a diaphragm of a capacitive microphone device
View Patent ↗A method of fabricating a diaphragm of a capacitive microphone device is provided. First, a substrate is provided, and a dielectric layer is formed on a first surface of the substrate. Than, a plurality of silicon spacers are formed on a surface of the dielectric layer, and the dielectric layer is patterned to form a plurality of dielectric bumps. Subsequently, a diaphragm layer is formed on a surface of the silicon spacers, a surface of the dielectric bumps, and the first surface of the substrate so that the diaphragm layer has a corrugate structure by virtue of the dielectric bumps. Thereafter, a planarization layer is formed on the diaphragm layer, and a second surface of the substrate is etched to form a plurality of openings corresponding to the corrugate structure. Following that, the dielectric bumps exposed through the openings are removed, and the planarization layer is removed.
1. A method of fabricating a diaphragm of a capacitive microphone device, comprising:
providing a substrate, and forming a dielectric layer on a first surface of the substrate;
forming a plurality of silicon spacers on a surface of the dielectric layer;
patterning the dielectric layer to form a plurality of dielectric bumps;
forming a diaphragm layer on a surface of the silicon spacers, a surface of the dielectric bumps, and the first surface of the substrate so that the diaphragm layer has a corrugate structure by virtue of the dielectric bumps;
forming a planarization layer on the diaphragm layer, and etching a second surface of the substrate to form a plurality of openings corresponding to the corrugate structure;
removing the dielectric bumps exposed through the openings; and
removing the planarization layer.
2. The method of claim 1 , wherein the dielectric layer comprises a silicon oxide layer.
3. The method of claim 1 , further comprising forming a plurality of vents in the diaphragm layer not corresponding to the dielectric bumps subsequent to forming the diaphragm layer.
4. The method of claim 1 , further comprising performing a thinning process on the second surface of the substrate prior to forming the openings.
5. The method of claim 1 , wherein forming the silicon spacers comprises:
depositing a silicon layer on the surface of the dielectric layer; and
etching a portion of the silicon layer and stopping etching at the dielectric layer to form the silicon spacers;
wherein each of the silicon spacers has a vertical sidewall.
6. The method of claim 5 , wherein the silicon layer comprises a polycrystalline silicon layer, an amorphous crystalline silicon layer, or a single crystalline silicon layer.
7. The method of claim 1 , wherein the diaphragm layer comprises a polycrystalline silicon layer, an amorphous crystalline silicon layer, or a single crystalline silicon layer.
8. The method of claim 1 , further comprising forming a metal layer on the surface of the diaphragm layer subsequent to removing the dielectric bumps exposed through the openings.
9. The method of claim 8 , further comprising segmenting the substrate to form a plurality of diaphragm structures subsequent to forming the metal layer.