BACKING SUBSTRATE STABILIZING DONOR SUBSTRATE FOR IMPLANT OR RECLAMATION

• US 20180019169A1
• Filed: 07/06/2017
• Published: 01/18/2018
• Est. Priority Date: 07/12/2016
• Status: Abandoned Application

• Current Assignee: QMAT, Inc.
• Original Assignee: QMAT, Inc.
• Inventors: HENLEY, Francois J.
• Application Number:
  US15/643,370
• Publication Number:
  US 20180019169A1
• Time in Patent Office: Days
• CPC Class Codes: H01J 2237/2001 Maintaining constant desired temperature
• CPC Class Codes: H01L 21/02002 Preparing wafers
• CPC Class Codes: H01L 21/02013 Grinding, lapping
• CPC Class Codes: H01L 21/02016 Backside treatment
• CPC Class Codes: H01L 21/02019 Chemical etching
• CPC Class Codes: H01L 21/02032 by reclaiming or re-processing
• CPC Class Codes: H01L 21/02079 Cleaning for reclaiming
• CPC Class Codes: H01L 21/185 Joining of semiconductor bodies for junction formation
• CPC Class Codes: H01L 21/26506 in group IV semiconductors
• CPC Class Codes: H01L 21/2654 in AIIIBV compounds
• CPC Class Codes: H01L 21/3006 of AIIIBV compounds
• CPC Class Codes: H01L 21/6835 using temporarily an auxiliary support
• CPC Class Codes: H01L 21/68721 characterised by edge clamping, e.g. clamping ring
• CPC Class Codes: H01L 21/68735 characterised by edge profile or support profile
• CPC Class Codes: H01L 21/68757 characterised by a coating or a hardness or a material
• CPC Class Codes: H01L 21/76254 with separation/delamination along an ion implanted layer, e.g. Smart-cut, Unibond
• CPC Class Codes: H01L 21/7813 leaving a reusable substrate, e.g. epitaxial lift off
• CPC Class Codes: H01L 2221/68368 used in a transfer process involving at least two transfer steps, i.e. including an intermediate handle substrate
• CPC Class Codes: H01L 2221/68381 Details of chemical or physical process used for separating the auxiliary support from a device or wafer
• CPC Class Codes: H01L 23/373 Cooling facilitated by selection of materials for the device or materials for thermal expansion adaptation, e.g. carbon
• CPC Class Codes: H01L 31/1896 : for thin-film semiconductors
• CPC Class Codes: H01L 33/0062 : for devices with an active region comprising only III-V compounds
• CPC Class Codes: H01L 33/0066 : with a substrate not being a III-V compound
• CPC Class Codes: H01L 33/007 : comprising nitride compounds
• CPC Class Codes: H01L 33/0075 : comprising nitride compounds
• CPC Class Codes: H01L 33/0093 : Wafer bonding; Removal of the growth substrate

Abstract

A donor substrate in a layer transfer process, is stabilized by attaching a backing substrate. The backing substrate allows thermal and mechanical stabilization during high-power implant processes. Upon cleaving the donor substrate to release a thin layer of material to a target, the backing substrate prevents uncontrolled release of internal stress leading to buckling/fracture of the donor substrate. The internal stress may accumulate in the donor substrate due to processes such as cleave region formation, bonding to the target, and/or the cleaving process itself, with uncontrolled bow and warp potentially precluding reclamation/reuse of the donor substrate in subsequent layer transfer processes. In certain embodiments the backing substrate may exhibit a Coefficient of Thermal Expansion (CTE) substantially matching, or complementary to, that of the donor substrate. In some embodiments the backing structure may include a feature such as a lip.

Claims

1. A method comprising:

providing a donor substrate comprising a first face and a second face;

attaching the first face to a backing substrate;

processing the donor substrate to create an internal stress;

bonding the second face to a target substrate;

cleaving the donor substrate in a cleave region to transfer a layer of material to the target substrate, with remaining material of the donor substrate staying attached to the backing substrate; and

reclaiming the remaining material while the first face of the donor substrate stays attached to the backing substrate.

2. A method as in claim 1 wherein the cleave region is formed by implanting particles into the donor substrate attached to the backing substrate, and the internal stress arises from the implanting.

3. A method as in claim 1 wherein the backing substrate exhibits a coefficient of thermal expansion similar to a coefficient of thermal expansion of the donor substrate.

4. A method as in claim 1 wherein an assembly comprising the donor substrate bonded to the backing substrate facilitates an implantation process, the cleaving, or the reclaiming.

5. A method as in claim 1 wherein the backing substrate clamps an edge of the donor substrate to restrain expansion of the donor substrate.

6. A method as in claim 1 wherein the reclaiming comprises thermal exposure.

7. A method as in claim 1 wherein the reclaiming comprises chemical exposure.

8. A method as in claim 7 wherein the chemical exposure comprises etching.

9. A method as in claim 6 wherein the chemical exposure comprises chemical mechanical polishing.

10. A method as in claim 1 wherein the reclaiming comprises grinding.

11. A method as in claim 1 wherein the reclaiming comprises plasma exposure.

12. A method as in claim 1 wherein the donor substrate comprises GaN.

13. A method as in claim 12 wherein the first face comprises a Ga face of the GaN donor substrate.

14. A method as in claim 12 wherein the first face comprises a N face of the GaN donor substrate.

15. A method as in claim 1 wherein the backing substrate comprises a lip.

16. A method as in claim 1 wherein the donor substrate comprises GaAs.

17. A method as in claim 16 wherein the backing substrate comprises sapphire.