INTEGRATED DRIVER PROCESS FLOW

• US 20030235932A1
• Filed: 05/28/2002
• Published: 12/25/2003
• Est. Priority Date: 05/28/2002
• Status: Active Grant

• Current Assignee: Silicon Light Machines Corporation (SCREEN Holdings Co., Ltd.)
• Original Assignee: Silicon Light Machines Corporation (SCREEN Holdings Co., Ltd.)
• Inventors: Hunter, James A.
• Granted Patent: US 6,767,751 B2
• Time in Patent Office: Days
• US Class Current: 438/27
• CPC Class Codes: B81B 2201/045 Optical switches
• CPC Class Codes: B81B 2207/015 the micromechanical device and the control or processing electronics being integrated on the same substrate
• CPC Class Codes: B81B 2207/07 Interconnects
• CPC Class Codes: B81C 1/00246 Monolithic integration, i.e. micromechanical structure and electronic processing unit are integrated on the same substrate
• CPC Class Codes: B81C 2201/016 Passivation
• CPC Class Codes: B81C 2203/0735 Post-CMOS, i.e. forming the micromechanical structure after the CMOS circuit
• CPC Class Codes: B81C 2203/0778 Topology for facilitating the monolithic integration not provided for in B81C2203/0764 - B81C2203/0771
• CPC Class Codes: G02B 26/0808 by means of one or more diffracting elements
• CPC Class Codes: H01L 27/0611 integrated circuits having a two-dimensional layout of components without a common active region

Abstract

An integrated device including one or more device drivers and a diffractive light modulator monolithically coupled to the one or more driver circuits. The one or more driver circuits are configured to process received control signals and to transmit the processed control signals to the diffractive light modulator. A method of fabricating the integrated device preferably comprises fabricating a front-end portion for each of a plurality of transistors, isolating the front-end portions of the plurality of transistors, fabricating a front-end portion of a diffractive light modulator, isolating the front end portion of the diffractive light modulator, fabricating interconnects for the plurality of transistors, applying an open array mask and wet etch to access the diffractive light modulator, and fabricating a back-end portion of the diffractive light modulator, thereby monolithically coupling the diffractive light modulator and the plurality of transistors.

Claims

1. A method of fabricating an integrated device comprising the steps of:

a. fabricating a front-end portion for each of a plurality of transistors;

b. isolating the front-end portions of the plurality of transistors;

c. fabricating a front-end portion of a diffractive light modulator;

d. isolating the front end portion of the diffractive light modulator;

e. fabricating interconnects for the plurality of transistors;

f. applying an open array mask and wet etch to access the diffractive light modulator; and

g. fabricating a back-end portion of the diffractive light modulator, thereby monolithically coupling the diffractive light modulator and the plurality of transistors.

2. The method of claim 1 wherein the plurality of transistors and the associated interconnects form one or more device drivers configured to process received control signals and to transmit the processed control signals to the diffractive light modulator.

3. The method of claim 1 wherein fabricating the front-end portion of the diffractive light modulator and fabricating the front-end portions for the plurality of transistors are performed using high temperature processing steps.

4. The method of claim 1 wherein fabricating interconnects and fabricating the back-end portion of the diffractive light modulator are performed using low temperature processing steps.

5. The method of claim 1 wherein isolating the front-end portions of the plurality of transistors comprises:

a. depositing an oxide layer over the front-end portions of the plurality of transistors; and

b. planarizing the oxide layer.

6. The method of claim 1 wherein isolating the front-end portion of the diffractive light modulator comprises:

a. depositing an oxide layer over the front-end portion of the diffractive light modulator; and

b. planarizing the oxide layer.

7. The method of claim 6 wherein fabricating the interconnects includes fabricating one or more metal layers.

8. The method of claim 7 further comprising removing metal from above the diffractive light modulator after each metal layer is fabricated.

9. The method of claim 8 wherein each metal layer is removed from above the diffractive light modulator by over-etching and the oxide layer deposited over the front-end portion of the diffractive light modulator is sufficiently thick as to allow for over-etching without damaging the front-end portion of the diffractive light modulator.

10. The method of claim 1 wherein the interconnects for the plurality of transistors include contacts to each of the plurality of transistors, further wherein the contacts include a maximum aspect ratio that limits a maximum combined thickness of the oxide layer over the front-end portions of the plurality of transistors and the oxide layer over the front end portion of the diffractive light modulator.

11. The method of claim 1 wherein the diffractive light modulator and the plurality of transistors are monolithically coupled to transmit control signals from the plurality of transistors to the diffractive light modulator such that the diffractive light modulator modulates an incident light beam in response to the control signals.

12. The method of claim 1 wherein the wet etch comprises about a 10:

1 buffered oxide wet etch to selectively etch the layers above the diffractive light modulator.

13. An integrated device comprising:

a. means for performing high temperature processing steps to fabricate a front-end portion of each of a plurality of transistors on a substrate;

b. means for isolating the front-end portions of the plurality of transistors;

c. means for performing high temperature processing steps to fabricate a front-end portion of a diffractive light modulator coupled to the substrate;

d. means for isolating the front-end portions of the diffractive light modulator;

e. means for performing low temperature processing steps to fabricate one or more metal layers which form interconnects for the plurality of transistors, thereby forming one or more driver devices;

f. means for applying an open array mask and wet etch to remove layers above the diffractive light modulator; and

g. means for performing low temperature processing steps to fabricate a back-end portion of the diffractive light modulator, thereby monolithically coupling the diffractive light modulator and the plurality of transistors.

14. An integrated device comprising:

a. one or more device drivers; and

b. a diffractive light modulator monolithically coupled to the one or more driver circuits, wherein the one or more driver circuits are configured to transmit control signals to the diffractive light modulator.

15. The integrated device of claim 14 wherein the diffractive light modulator receives the control signals and in response thereto modulates a light beam incident to the diffractive light modulator.

16. The integrated device of claim 14 wherein the one or more device drivers include a plurality of transistors and associated interconnects.

17. The integrated device of claim 16 wherein the transistors are MOS transistors.

18. The integrated device of claim 16 wherein each of the plurality of transistors includes a front-end portion and the diffractive light modulator includes a front-end portion such that the front-end portion of the diffractive light modulator is isolated from the front-end portion of the plurality of transistors by a first layer of deposited oxide.

19. The integrated device of claim 18 wherein each of the plurality of transistors includes a back-end portion comprising interconnects and the diffractive light modulator includes a back-end portion comprising interconnects such that the diffractive light modulator is monolithically coupled to the one or more driver circuits via the respective interconnects.

20. The integrated device of claim 19 wherein the transistor interconnects include one or more metal layers and the front-end portion of the diffractive light modulator is isolated from the one or more metal layers by a second layer of deposited oxide, further wherein as a first metal layer of the transistor interconnects is fabricated, the metal is removed from an area above the diffractive light modulator by over-etching, and the second deposited oxide layer over the front-end portion of the diffractive light modulator is sufficiently thick as to allow for over-etching without damaging the front-end portion of the diffractive light modulator.