IP Library Granted Patent US 9,330,952
Granted Patent B2
US 9,330,952 · App. 13/520,139 · Granted May 3, 2016

Bipolar mobile electrostatic carriers for wafer processing

Inventors: Mehrdad M. Moslehi (Los Altos, CA); David Xuan-Qi Wang (Fremont, CA)
Assignee: Solexel, Inc.
H01L21/683G03F7/70708H01L21/6831H01L21/6833H01L21/76251H01L21/76879
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Quick Facts
Patent No.
US 9,330,952
App. No.
13/520,139
Granted
May 3, 2016
Kind
B2
Abstract

In one embodiment, there is provided a carrier comprising a top semiconductor layer having isolated positive electrode regions and isolated negative electrode regions separated by a frontside trench through the top semiconductor layer extending at least to an underlying insulating layer positioned between the top semiconductor layer and a bottom semiconductor layer. A dielectric layer covers the top exposed surfaces of the carrier. Backside trenches through the bottom semiconductor layer extending at least to the insulating layer form isolated backside regions corresponding to the frontside positive and negative electrode regions. Backside contacts positioned on the bottom semiconductor layer and coupled to the positive and negative electrode regions allow for the electric charging of the frontside electrode regions.

Claims (45)

1. A bipolar mobile electrostatic carrier for wafer processing, comprising:

a top crystalline semiconductor layer having isolated positive electrode regions and isolated negative electrode regions;

a frontside trench through said top crystalline semiconductor layer extending at least to an underlying insulating layer, said frontside trench separating said negative electrode regions and said positive electrode regions;

said insulating layer positioned between said top crystalline semiconductor layer and a bottom crystalline semiconductor layer;

a dielectric layer covering exposed surface areas of said top crystalline semiconductor layer and surface areas of said insulating layer exposed by said frontside trench;

said bottom crystalline semiconductor layer having a backside trench through said bottom crystalline semiconductor layer extending at least to said insulating layer, said backside trench forming isolated backside regions on the bottom surface of said bottom crystalline semiconductor layer aligned to said negative electrode regions and said positive electrode regions on said top crystalline semiconductor layer; and

backside contacts on said isolated backside regions, said backside contacts coupled to said positive electrode regions and said negative electrode regions, said backside contacts for charging said positive electrode regions and said negative electrode regions.

2. The bipolar mobile electrostatic carrier of claim 1 , wherein said insulating layer is a silicon dioxide layer.

3. The bipolar mobile electrostatic carrier of claim 1 , wherein said insulating layer is a thermally grown silicon dioxide layer.

4. The bipolar mobile electrostatic carrier of claim 1 , wherein said dielectric layer is a dielectric stack layer comprising a silicon dioxide layer and a silicon nitride layer.

5. The bipolar mobile electrostatic carrier of claim 1 , wherein said dielectric layer is a dielectric stack layer comprising a thermally grown silicon dioxide layer and a LPCVD silicon nitride layer.

6. The bipolar mobile electrostatic carrier of claim 1 , wherein said crystalline semiconductor layers are crystalline silicon layers.

7. The bipolar mobile electrostatic carrier of claim 6 , wherein said crystalline semiconductor layers are mono-crystalline or polycrystalline silicon layers or silicon layers.

8. The bipolar mobile electrostatic carrier of claim 1 , wherein said frontside trench is formed in a hub and spoke design.

9. The bipolar mobile electrostatic carrier of claim 1 , wherein said frontside trench forms dual pairs of isolated positive electrode regions and isolated negative electrode regions.

10. The bipolar mobile electrostatic carrier of claim 1 , wherein a plurality of said bipolar mobile electrostatic carriers are arranged on a tray for batch wafer processing.

11. The bipolar mobile electrostatic carrier of claim 1 , wherein said bipolar mobile electrostatic carrier is for thin wafer processing, said thin wafer having a thickness in the range of 1 μm to 100 μm.

12. A method for fabricating a bipolar mobile electrostatic carrier for wafer processing, comprising the steps of:

forming a frontside trench in the top surface of a semiconductor substrate that extends at least to a buried insulating layer, said frontside trench forming isolated frontside regions in said top surface of said semiconductor substrate;

depositing a dielectric layer on all exposed surfaces of said semiconductor substrate and surface areas of said insulating layer exposed by said frontside trench;

forming a backside trench in the bottom surface of said semiconductor substrate that extends at least to said buried insulating layer, said backside trench forming isolated backside regions on said bottom surface of said semiconductor substrate aligned to said isolated regions on said top surface of said substrate; and

forming backside contact holes in said isolated backside regions on said bottom surface extending to said isolated frontside regions, said backside contact holes aligned to said isolated frontside regions to form backside contacts coupled to said isolated regions on said top surface of said semiconductor substrate.

13. The method for fabricating the bipolar mobile electrostatic carrier of claim 12 , wherein said semiconductor substrate is a silicon-on-insulator semiconductor substrate.

14. The method for fabricating the bipolar mobile electrostatic carrier of claim 12 , wherein said semiconductor substrate comprises a top semiconductor substrate bonded to a bottom semiconductor substrate and an insulating layer positioned between said top semiconductor substrate and said bottom semiconductor substrate.

15. The method for fabricating the bipolar mobile electrostatic carrier of claim 12 , further comprising the steps for forming said semiconductor substrate, the steps comprising:

forming an insulating layer on a first semiconductor wafer; and

bonding said first semiconductor wafer to a second semiconductor wafer.

16. The method for fabricating the bipolar mobile electrostatic carrier of claim 12 , wherein said insulating layer is a silicon dioxide layer.

17. The method for fabricating the bipolar mobile electrostatic carrier of claim 12 , wherein said insulating layer is a thermally grown silicon dioxide layer.

18. The method for fabricating the bipolar mobile electrostatic carrier of claim 12 , wherein said dielectric layer is a dielectric stack layer comprising a silicon dioxide layer and a silicon nitride layer.

19. The method for fabricating the bipolar mobile electrostatic carrier of claim 12 , wherein said dielectric layer is a dielectric stack layer comprising a thermally grown silicon dioxide layer and a LPCVD silicon nitride layer.

20. The method for fabricating the bipolar mobile electrostatic carrier of claim 12 , wherein said semiconductor substrate is a crystalline silicon substrate.

21. The method for fabricating the bipolar mobile electrostatic carrier of claim 12 , wherein said semiconductor substrate is a mono-crystalline or polycrystalline silicon substrate.

22. The method for fabricating the bipolar mobile electrostatic carrier of claim 12 , wherein said frontside trench, said backside trench, and said backside contact holes are formed according to a deep reactive ion etch process.

23. The method for fabricating the bipolar mobile electrostatic carrier of claim 12 , wherein said frontside trench, said backside trench, and said backside contact holes are formed according to a laser drilling process.

24. The method for fabricating the bipolar mobile electrostatic carrier of claim 12 , wherein said frontside trench, said backside trench, and said backside contact holes are formed according to an anisotropic etch process.

25. The method for fabricating the bipolar mobile electrostatic carrier of claim 12 , wherein said frontside trench is formed in a hub and spoke design.

26. The method for fabricating the bipolar mobile electrostatic carrier of claim 12 , wherein said frontside trench forms dual pairs of isolated positive electrode regions and isolated negative electrode regions.

27. A bipolar mobile electrostatic carrier for semiconductor wafer support and/or processing, comprising:

a top electrically conductive semiconductor layer having isolated positive electrode regions and isolated negative electrode regions;

a frontside trench through said top electrically conductive semiconductor layer extended to at least one underlying insulating layer, said frontside trench separating said negative electrode regions and said positive electrode regions;

said insulating layer positioned between said top electrically conductive semiconductor layer and a bottom electrically conductive semiconductor layer;

a dielectric layer covering exposed surface areas of said top electrically conductive semiconductor layer and surface areas of said insulating layer exposed by said frontside trench;

said bottom electrically conductive semiconductor layer having a backside trench through said bottom electrically conductive semiconductor layer extended to at least said insulating layer, said backside trench forming isolated backside regions on the bottom surface of said bottom electrically conductive semiconductor layer aligned to said negative electrode regions and said positive electrode regions on said top electrically conductive semiconductor layer; and

backside contacts on said isolated backside regions, said backside contacts coupled to said positive electrode regions and said negative electrode regions, said backside contacts for electrically charging said positive electrode regions and said negative electrode regions.

Assignments (6)
ASSIGNMENT OF LOAN DOCUMENTS Recorded Sep 29, 2017
From: OPUS BANK
To: OB REALTY, LLC
Reel/Frame 044062/0383 →
CHANGE OF NAME Recorded Jul 28, 2017
From: SOLEXEL, INC.
To: BEAMREACH SOLAR, INC.
Reel/Frame 043367/0649 →
RECORDATION OF FORECLOSURE OF PATENT PROPERTIES Recorded Jul 27, 2017
From: OB REALTY, LLC
To: OB REALTY, LLC
Reel/Frame 043350/0822 →
CHANGE OF NAME Recorded Jul 26, 2017
From: SOLEXEL, INC.
To: BEAMREACH SOLAR, INC.
Reel/Frame 043342/0439 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Feb 19, 2015
From: MOSLEHI, MEHRDAD M.; WANG, DAVID XUAN-QI
To: SOLEXEL, INC.
Reel/Frame 034984/0245 →
SECURITY INTEREST Recorded Jan 7, 2015
From: SOLEXEL, INC.
To: OPUS BANK
Reel/Frame 034731/0001 →
Continuity (2)
Provisional Application 61291156 · Dec 30, 2009
Related Publication 20130141833A1 · Jun 6, 2013