Method for fabricating vertically-offset interdigitated comb actuator device
View Patent ↗The present invention relates to systems and methods for fabricating microscanners. The fabrication processes employed pursuant to some embodiments are compatible with well known CMOS fabrication techniques, allowing devices for control, monitoring and/or sensing to be integrated onto a single chip. Both one- and two-dimensional microscanners are described. Applications including optical laser surgery, maskless photolithography, portable displays and large scale displays are described.
1. A method for fabricating an actuator device having vertically offset interdigitated-comb actuators including a fixed-comb actuator and a moving-comb actuator, comprising:
forming a low temperature oxide layer on a semiconductor wafer; and,
selectively removing said low temperature oxide layer at the locations of the fixed combs of said fixed-comb actuator; and,
forming said fixed-comb actuator and said moving-comb actuator simultaneously by photolithographic patterning and etching; and,
performing timed deep reactive ion etching to define the vertical height of said fixed-comb actuator without significantly affecting the height of said moving-comb actuator creating thereby vertically offset interdigitated-comb actuators; and,
opening the backside of said actuator device and releasing said actuator device in an etch solution; and,
wherein the temperature of said actuator device exceeds about 500 deg. C. at no time during the fabrication process.
2. A method as in claim 1 wherein said low temperature oxide layer has a thickness in the range from about 0.5 μm to about 1.0 μm.
3. A method as in claim 1 wherein the separation between the comb fingers of said actuators is in the range from about 0.014 μm to about 0.8 μm.
4. A method as in claim 1 further comprising:
forming a mirror integrally with said moving-comb actuator thereby forming a microscanner.