IP Library Granted Patent US 11,550,140
Granted Patent B2
US 11,550,140 · App. 16/868,306 · Granted Jan 10, 2023

Backside etch process for transparent silicon oxide technology

Inventors: Jacob Becker (Gilbert, AZ); Jon Burnsed (Tempe, AZ)
Assignee: L3HARRIS TECHNOLOGIES, INC.
G02B23/125G02B27/0172H01L27/3209H01L51/0017H01L51/56G02B2027/0132H01L2251/303
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Quick Facts
Patent No.
US 11,550,140
App. No.
16/868,306
Granted
Jan 10, 2023
Kind
B2
Abstract

Increasing transparency of one or more micro-displays. A method includes attaching a transparent cover to at least a portion of a semiconductor wafer. The at least a portion of the semiconductor wafer includes the one or more micro-displays. The one or more micro-displays include one or more active silicon areas. The method further includes, after the transparent cover has been attached to the at least a portion of the semiconductor wafer, removing silicon between one or more of the active silicon areas.

Claims (33)

1. A method of increasing transparency of one or more micro-displays, the method comprising:

attaching a transparent cover to at least a portion of a semiconductor wafer, the at least a portion of the semiconductor wafer comprising the one or more micro-displays, the one or more micro-displays comprising one or more active silicon areas;

after the transparent cover has been attached to the at least a portion of the semiconductor wafer, removing silicon between one or more of the active silicon areas; and

removing portions of a silicon oxide covering the silicon between the one or more of the active silicon areas and using remaining portions of the silicon oxide as a mask for removing the silicon between the one or more of the active silicon areas.

2. The method of claim 1 , wherein the transparent cover comprises a glass material.

3. The method of claim 1 , further comprising adding an OLED stack to the portion of a semiconductor wafer.

4. The method of claim 1 , wherein removing silicon between the one or more of the active silicon areas comprises removing non-active silicon islands formed by forming oxide trenches in silicon of the at least a portion of a semiconductor wafer.

5. The method of claim 1 , wherein removing silicon between the one or more of the active silicon areas comprises removing portions of a silicon substrate to form active silicon islands.

6. The method of claim 1 , further comprising filling an area between with active silicon areas with a backside fill material.

7. The method of claim 1 , further comprising coupling one of the micro-displays to a fiber optic coupled to an image intensifier of a night-vision system to cause a digital heads-up display to be displayed in conjunction with an analog night vision image by light from the analog night vision image being transmitted through the micro-display.

8. The method of claim 1 , wherein at least one of the micro-displays comprises at least a 36 μm pitch and has a transparency of at least 75% as a result of removing silicon between one or more of the active silicon areas.

9. The method of claim 1 , wherein at least one of the micro-displays comprises at least a 22.5 μm pitch and has a transparency of at least 60% as a result of removing silicon between one or more of the active silicon areas.

10. The method of claim 1 , wherein at least one of the micro-displays comprises at least a 17.5 μm pitch and has a transparency of at least 50% as a result of removing silicon between one or more of the active silicon areas.

11. A method of increasing transparency of one or more micro-displays, the method comprising:

obtaining a semiconductor wafer, the semiconductor wafer comprising:

a substrate comprising silicon;

a buried oxide layer coupled to the substrate; and

a plurality of active silicon islands coupled to the buried oxide layer, and separated from each other by non-active silicon islands and oxide trenches;

attaching a cover glass to the semiconductor wafer;

after attaching the cover glass to the semiconductor wafer, removing the silicon substrate; and

after attaching the cover glass to the semiconductor wafer, removing at least a portion of the non-active silicon islands and oxide trenches.

12. The method of claim 11 , wherein removing at least the portion of the non-active silicon islands and oxide trenches comprises removing a portion of the buried oxide layer, and using remaining buried oxide as a hard mask.

13. The method of claim 11 , further comprising adding a transparent backfill material between the active silicon islands after removing the at least a portion of the non-active silicon islands and oxide trenches.

14. The method of claim 13 , wherein the transparent backfill material comprises a two-part epoxy for coupling a micro-display to a fiber optic for an analog night vision system to allow light from an image intensifier to be transmitted through the micro-display.

15. The method of claim 11 , wherein removing at least the portion of the non-active silicon islands and oxide trenches results in at least an 80% increase in transparency for at least one micro display.

16. A micro-display comprising:

a glass cover;

a semiconductor wafer coupled to the glass cover, the semiconductor wafer comprising:

a buried oxide layer;

a plurality of active silicon islands coupled to the buried oxide layer, and separated from each other by space created by non-active silicon islands and oxide trenches having been removed; and

a transparent backfill material between the active silicon islands, the transparent backfill material comprising a two-part epoxy for coupling the micro-display to a fiber optic for an analog night vision system to allow light from an image intensifier to be transmitted through the micro-display.

17. The micro-display of claim 16 , wherein the buried oxide layer comprises a hard mask used to remove the non-active silicon islands.

18. The micro-display of claim 16 , further comprising a transparent backfill material between the active silicon islands.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded May 7, 2020
From: BECKER, JACOB; BURNSED, JON
To: L3HARRIS TECHNOLOGIES, INC.
Reel/Frame 052598/0837 →
Continuity (1)
Related Publication 20210349301A1 · Nov 11, 2021
Cited By (1)
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