Carrier-assisted method for parting crystalline material along laser damage region
A method for removing a portion of a crystalline material (e.g., SiC) substrate includes joining a surface of the substrate to a rigid carrier (e.g., >800 μm thick), with a subsurface laser damage region provided within the substrate at a depth relative to the surface. Adhesive material having a glass transition temperature above 25° C. may bond the substrate to the carrier. The crystalline material is fractured along the subsurface laser damage region to produce a bonded assembly including the carrier and a portion of the crystalline material. Fracturing of the crystalline material may be promoted by (i) application of a mechanical force proximate to at least one carrier edge to impart a bending moment in the carrier; (ii) cooling the carrier when the carrier has a greater coefficient of thermal expansion than the crystalline material; and/or (iii) applying ultrasonic energy to the crystalline material.
1. A crystalline material processing method comprising:
temporarily bonding a rigid carrier having a thickness of greater than 800 microns to a first surface of a crystalline material comprising a semiconductor with an intervening adhesive material, wherein the crystalline material comprises a substrate having a subsurface laser damage region at a depth relative to the first surface, the rigid carrier has a modulus of elasticity of at least 20 GPa, and the adhesive material has a glass transition temperature T g of greater than 25° C.; and
fracturing the crystalline material along or proximate to the subsurface laser damage region to yield a bonded assembly comprising the rigid carrier, the adhesive material, and a portion of the crystalline material removed from the substrate, wherein in the bonded assembly, the portion of the crystalline material removed from the substrate comprises a thickness of at least 160 μm.
2. The crystalline material processing method of claim 1 , wherein the adhesive material comprises a thermoplastic material.
3. The crystalline material processing method of claim 1 , wherein the adhesive material has a glass transition temperature T g of at least 35° C.
4. The crystalline material processing method of claim 1 , wherein the adhesive material has a Shore D durometer value of at least 70 when the adhesive material is at 25° C.
5. The crystalline material processing method of claim 1 , wherein the adhesive material has a modulus of elasticity of at least 7 MPa when the adhesive material is at 25° C.
6. The crystalline material processing method of claim 1 , wherein the adhesive material has a thickness of less than 50 microns.
7. The crystalline material processing method of claim 1 , wherein:
the rigid carrier comprises a first face and a second face that opposes the first face;
the adhesive material is arranged in contact with the first face; and
the second face is devoid of any adhesive material and devoid of any stress-producing material.
8. The crystalline material processing method of claim 1 , wherein the rigid carrier comprises a crystalline material.
9. The crystalline material processing method of claim 1 , wherein a coefficient of thermal expansion (CTE) of the rigid carrier is greater than a CTE of the substrate at 25° C., and wherein the fracturing comprises cooling at least the rigid carrier to promote fracture of the crystalline material along or proximate to the subsurface laser damage region.
10. The crystalline material processing method of claim 1 , wherein the fracturing comprises application of ultrasonic energy to at least one of the rigid carrier or the substrate.
11. The crystalline material processing method of claim 1 , wherein at least one of a maximum length or maximum width of at least a portion of the rigid carrier exceeds a corresponding maximum length or maximum width of the substrate, the fracturing comprises applying a mechanical force proximate to at least one edge of the rigid carrier, and the mechanical force is configured to impart a bending moment in at least a portion of the rigid carrier.
12. The crystalline material processing method of claim 1 , further comprising performing at least one additional processing step on the portion of the crystalline material while the portion of the crystalline material remains part of the bonded assembly.
13. The crystalline material processing method of claim 1 , further comprising bonding an additional rigid carrier having a modulus of elasticity of at least 20 GPa to a second surface of the crystalline material that opposes the first surface, prior to said fracturing.
14. The crystalline material processing method of claim 1 , wherein the crystalline material comprises SiC.
15. The crystalline material processing method of claim 1 , further comprising roughening, texturing, and/or etching at least one of (i) the first surface of the crystalline material or (ii) an adjacent surface of the rigid carrier prior to the temporarily bonding of the rigid carrier to the first surface of a crystalline material with the adhesive material.
16. The crystalline material processing method of claim 1 , wherein the portion of the crystalline material removed from the substrate comprises a free-standing wafer configured for growth of at least one epitaxial layer thereon.
17. The crystalline material processing method of claim 1 , wherein the portion of the crystalline material removed from the substrate comprises a device wafer including at least one epitaxial layer grown thereon.
18. A crystalline material processing method comprising:
bonding a first crystalline carrier to a first surface of a crystalline material comprising a semiconductor, wherein the crystalline material comprises a substrate having a subsurface laser damage region at a depth relative to a first surface of the substrate;
bonding a second crystalline carrier to a second surface of the crystalline material; and
following the bonding steps, fracturing the crystalline material along or proximate to the subsurface laser damage region to yield a bonded assembly comprising the first crystalline carrier and a portion of the crystalline material removed from the substrate, wherein in the bonded assembly, the portion of the crystalline material removed from the substrate comprises a thickness of at least 160 μm.
19. The crystalline material processing method of claim 18 , wherein at least one of the bonding of the first crystalline carrier to the first surface of the crystalline material or the bonding of the second crystalline carrier to the second surface of the crystalline material comprises anodic bonding.
20. The crystalline material processing method of claim 18 , wherein at least one of the bonding of the first crystalline carrier to the first surface of the crystalline material or the bonding of the second crystalline carrier to the second surface of the crystalline material comprises adhesive bonding utilizing an adhesive material.
21. The crystalline material processing method of claim 20 , wherein:
the first crystalline carrier comprises a first face and a second face that opposes the first face;
the adhesive material is arranged in contact with the first face; and
the second face is devoid of any adhesive material and devoid of any stress-producing material.
22. The crystalline material processing method of claim 20 , wherein the adhesive material comprises at least one of the following characteristics (a) to (c): (a) the adhesive material comprises a thermoplastic material; (b) the adhesive material has a Shore D durometer value of at least 70 when the adhesive material is at 25° C., or (c) the adhesive material has a modulus of elasticity of at least 7 MPa when the adhesive material is at 25° C.
23. A crystalline material processing method comprising:
bonding a rigid carrier to a first surface of a crystalline material comprising a semiconductor, wherein the crystalline material comprises a substrate having a subsurface laser damage region at a depth relative to the first surface, the rigid carrier comprises a thickness of greater than 850 microns and has a modulus of elasticity of at least 20 GPa, and the rigid carrier comprises a crystalline carrier; and
fracturing the crystalline material along or proximate to the subsurface laser damage region to yield a bonded assembly comprising the rigid carrier and a portion of the crystalline material removed from the substrate, wherein in the bonded assembly, the portion of the crystalline material removed from the substrate comprises a thickness of at least 160 μm.
24. The crystalline material processing method of claim 23 , wherein the bonding of the rigid carrier to the crystalline material comprises adhesive bonding utilizing an adhesive material arranged between the rigid carrier and the crystalline material.
25. The crystalline material processing method of claim 24 , wherein the adhesive material comprises at least one of the following characteristics (a) to (d): (a) the adhesive material has a glass transition temperature T g of greater than 25° C.; (b) the adhesive material has a Shore D durometer value of at least 70 when the adhesive material is at 25° C.; (c) the adhesive material has a modulus of elasticity of at least 7 MPa when the adhesive material is at 25° C., or (d) the adhesive material comprises a thermoplastic material.
26. The crystalline material processing method of claim 23 , further comprising performing at least one additional processing step on the portion of the crystalline material while the portion of the crystalline material remains part of the bonded assembly.
27. The crystalline material processing method of claim 23 , further comprising bonding an additional rigid carrier having a modulus of elasticity of at least 20 GPa to a second surface of the crystalline material that opposes the first surface, prior to said fracturing.
28. A crystalline material processing method comprising:
bonding a rigid carrier to a first surface of a crystalline material comprising a semiconductor, wherein the crystalline material comprises a substrate having a subsurface laser damage region at a depth relative to the first surface, the rigid carrier has a modulus of elasticity of at least 20 GPa, and a coefficient of thermal expansion (CTE) of the rigid carrier is different than the CTE of the substrate at 25° C. to provide a CTE mismatch between the rigid carrier and the substrate; and
fracturing the crystalline material along or proximate to the subsurface laser damage region due to forces created by the CTE mismatch between the rigid carrier and the substrate, to yield a bonded assembly comprising the rigid carrier and a portion of the crystalline material removed from the substrate, wherein in the bonded assembly, the portion of the crystalline material removed from the substrate comprises a thickness of at least 160 μm.
29. The crystalline material processing method of claim 28 , wherein:
the rigid carrier comprises a first face and a second face that opposes the first face;
the first face is proximate to the first surface of the crystalline material; and
the second face is devoid of any stress-producing material.
30. The crystalline material processing method of claim 1 , wherein in the bonded assembly, the portion of the crystalline material removed from the substrate comprises a thickness of at least 240 μm.