Isolation scheme for reducing film stress in a MEMS device
AssigneeHoneywell International Inc.
InventorsGregory Brown, Curtis Rahn
Life of this patent
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Abstract
A method of electrically isolating a MEMS device is provided. In one example, a piezo-resistive pressure sensor having an exposed silicon region undergoes a Local Oxidation of Silicon (LOCOS) process. An electrically insulating structure is created in the LOCOS process. The insulating structure has a rounded, or curved, interface with the piezo-resistive pressure sensor. The curved interface mitigates stresses associated with exposure to high temperatures and pressures. Additionally, the electrically insulating line may be patterned so that it has curved angles, further mitigating stress.
Claims20
A method of creating electrical isolation for a Micro-Electro-Mechanical System (MEMS) device including a silicon region that is to be oxidized, the method comprising:
- creating a mask layer on top of the MEMS device, the mask layer substantially covering the MEMS device and defining an exposed portion of the silicon region;
- and
- growing a silicon dioxide (SiO2) layer in a Local Oxidation of Silicon (LOCOS) process on top of the silicon region, the silicon region being consumed so as to create the SiO2 layer, the SiO2 layer and the silicon region comprising a curved interface, the curved interface being produced in the LOCOS process and reducing film stress associated with exposure to high temperatures and pressures.
A Micro-Electro-Mechanical System (MEMS) device comprising:
- a non-oxidized silicon region, the non-oxidized region located next to an oxidized silicon region, the oxidized region providing electrical isolation to the MEMS device;
- an interface located in between the non-oxidized region and the oxidized region, the interface being created in a Local Oxidation of Silicon (LOCOS) process, the interface being substantially curved so as to reduce film stresses associated with exposure to high temperatures and pressures.
A method of electrically isolating first and second Micro-Electro-Mechanical System (MEMS) devices comprising a silicon region located in between the first and second MEMS devices, the method comprising:
- creating a mask layer on top of the first and second MEMS devices, the mask layer substantially covering the first and second MEMS devices and defining an exposed portion of the silicon region;
- growing a silicon dioxide (SiO2) layer in a Local Oxidation of Silicon (LOCOS) process on top of the silicon region, the silicon region being consumed so as to create the SiO2 layer, the SiO2 layer and the silicon region comprising a curved interface, the curved interface being produced in the LOCOS process and reducing film stress associated with exposure to high temperatures and pressures;
- and
- patterning the SiO2 layer with a curved angle so as to further reduce film stress associated with exposure to high temperatures.
Dependencies are inferred from the claim text.