Cavity forming method for a sensor chip, manufacturing method thereof, chip and electronics apparatus
A method for forming a cavity of a sensor chip. The method comprises forming a first groove (a 2 ) on a substrate (a 1 ); bonding a covering layer (a 4 ) onto the substrate (a 1 ) to cover the first groove (a 2 ), thereby forming a cavity; and etching the covering layer (a 4 ) to decrease a thickness of the covering layer. The method can implement a thinner thickness of a film, thereby improving the sensitivity of a sensor.
1. A method for forming a cavity in a MEMS pressure sensor chip, comprising:
forming a first groove in a substrate;
bonding a covering layer onto the substrate to cover the first groove, so as to form a cavity; and
etching the covering layer to lower the thickness of the covering layer,
wherein the step of etching the covering layer further comprises: patterning the covering layer to etch a portion of the covering layer corresponding to the cavity, with other portions of the covering layer remaining.
2. The method according to claim 1 , wherein the step of bonding a covering layer onto the substrate further comprises: bonding the covering layer onto the substrate through a fusion bonding.
3. The method according to claim 1 , wherein the step of bonding a covering layer onto the substrate further comprises: bonding the covering layer onto the substrate through a bonding layer.
4. The method according to claim 1 , wherein the step of etching the covering layer further comprises: wet-etching the covering layer.
5. The method according to claim 1 , wherein the etched covering layer has a thickness lower than 10 μm.
6. The method according to claim 1 , further comprising: grinding the covering layer to lower a thickness of the covering layer before etching the covering layer.
7. The method according to claim 1 , further comprising: forming a thermal oxide layer on an etched surface of the covering layer, and then removing the thermal oxide layer to re-lower the thickness of the covering layer.
8. A method for manufacturing a MEMS pressure sensor chip, comprising: forming a cavity in the MEMS pressure sensor chip by using the method according to claim 1 .
9. A MEMS pressure sensor chip, which is manufactured by using the method according to claim 8 .