Mirror via conductivity for DMD pixel

Patent metadata

Field	Value
Publication number	US-11409098-B2
Application number	US-201715818973-A
Country	US
Kind code	B2
Filing date	Nov 21, 2017
Priority date	Nov 21, 2017
Publication date	Aug 9, 2022
Grant date	Aug 9, 2022

Abstract

A method includes forming a first aluminum silicon layer on a metal layer and forming a titanium nitride layer (or other titanium-based layer) on a surface of the aluminum-silicon layer opposite the metal layer. The method further includes etching the titanium nitride layer to create a titanium nitride pad and forming a torsion hinge in the metal layer. The titanium nitride pad is on the torsion hinge. The method also includes depositing a sacrificial layer over the torsion hinge and titanium nitride pad, forming a via in the sacrificial layer from a surface of the sacrificial layer opposite the torsion hinge to the titanium nitride pad, depositing a metal mirror layer on a surface of the sacrificial layer opposite the torsion hinge and into the via, and removing the sacrificial layer.

First claim

What is claimed is:

1. An apparatus, comprising:
a semiconductor substrate;
a hinge having a first side and a second side opposite the first side, the first side facing the semiconductor substrate;
an etch stop layer on the second side of the hinge;
a titanium-based pad on the etch stop layer;
a mirror; and
a mirror via coupling the mirror and the titanium-based pad.

2. The apparatus of claim 1 , wherein the hinge comprises metal and the mirror comprises metal.

3. The apparatus of claim 1 , further comprising an aluminum silicon layer between the titanium-based pad and the hinge.

4. The apparatus of claim 3 , wherein the aluminum silicon layer is approximately 200 {acute over (Å)} thick.

5. The apparatus of claim 1 , wherein the titanium-based pad has a thickness of approximately 50 {acute over (Å)}.

6. The apparatus of claim 1 , wherein the titanium-based pad comprises titanium nitride.

7. The apparatus of claim 1 , wherein the apparatus is a digital micromirror device (DMD).

8. The apparatus of claim 1 , wherein the hinge is a torsion hinge.

9. The apparatus of claim 1 , wherein the hinge is configured to rotate the mirror.

10. The apparatus of claim 1 , wherein the titanium-based pad comprises titanium-tungsten or titanium-aluminum nitride.

11. A device comprising:
a semiconductor substrate;
a hinge having a first side and a second side, the first side of the hinge facing the semiconductor substrate;
bias vias coupled to the hinge;
an etch stop layer on the second side of the hinge;
a titanium-based pad on the etch stop layer;
a mirror; and
a mirror via coupling the mirror and the titanium-based pad.

12. The device of claim 11 , wherein the hinge comprises metal and the mirror comprises metal.

13. The device of claim 11 , wherein the titanium-based pad comprises titanium nitride.

14. The device of claim 11 , wherein the titanium-based pad comprises titanium-tungsten or titanium-aluminum nitride.

15. The apparatus of claim 1 , wherein the etch stop layer comprises aluminum silicon.

16. The apparatus of claim 1 , wherein the titanium-based pad is shaped on the hinge before the hinge is shaped.

17. The device of claim 11 , wherein the etch stop layer comprises aluminum silicon.

18. The device of claim 11 , wherein the titanium-based pad is shaped on the hinge before the hinge is shaped.

19. The device of claim 11 , wherein the etch stop layer, the titanium-base pad, and the mirror via are configured to conduct a bias voltage received through the bias vias to the mirror.

Assignees

• Texas Instruments Inc

Inventors

• Sherwin Lucius M
• Yuan Jesse
• Boorananut Noppawan

Classifications

• G02B26/0833 Primary

  the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD (G02B26/0825 takes precedence; micromechanical devices in general B81B) · CPC title