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 .- 109 . (canceled)
110 . A semiconductor processing method, comprising:
temporarily providing an adhesive material on a semiconductor wafer, the semiconductor wafer comprising a substrate and one or more epitaxial layers on a first surface of the substrate, wherein the substrate has a damage region at a depth in the substrate, wherein the adhesive material is on the one or more epitaxial layers;
temporarily bonding a carrier to the semiconductor wafer using the adhesive material, and
fracturing the substrate along or proximate to the damage region to yield a bonded assembly comprising the carrier, the adhesive material, the one or more epitaxial layers and a portion of the substrate.
111 . The semiconductor processing method of claim 110 , further comprising:
removing the carrier from the bonded assembly.
112 . The semiconductor processing method of claim 110 , further comprising:
removing the adhesive material from the bonded assembly.
113 . The semiconductor processing method of claim 110 , wherein fracturing the substrate along or proximate to the damage region comprises:
temporarily bonding a second carrier to a second surface of the semiconductor wafer, the second surface being opposite the first surface; and
fracturing the substrate along or proximate to the damage region to yield a second bonded assembly comprising the second carrier and a second portion of the substrate.
114 . The semiconductor processing method of claim 113 , wherein the method comprises:
removing the second carrier from the second bonded assembly; and
forming one or more second epitaxial layers on the second portion of the substrate.
115 . The semiconductor processing method of claim 110 , wherein the damage region is a laser damage region.
116 . The semiconductor processing method of claim 110 , wherein prior to temporarily providing an adhesive material on the semiconductor wafer, the method comprises forming one or more conductive contacts on the one or more epitaxial layers.
117 . The semiconductor processing method of claim 110 , wherein the method comprises:
inducing the damage region in the substrate with one or more lasers.
118 . The semiconductor processing method of claim 117 , wherein the method comprises:
removing a rounded edge of the substrate prior to inducing the damage region in the substrate with one or more lasers.
119 . The semiconductor processing method of claim 110 , wherein the substrate comprises silicon carbide.
120 . The semiconductor processing method of claim 110 , wherein the adhesive material comprises a thermoplastic material.
121 . The semiconductor processing method of claim 110 , wherein the adhesive material has a glass transition temperature T g of greater than 25° C.
122 . The semiconductor processing method of claim 110 , wherein the adhesive material has a Shore D durometer value of at least about 70 when the adhesive material is at 25° C.
123 . The semiconductor processing method of claim 110 , wherein the adhesive material has a modulus of elasticity of at least about 7 MPa when the adhesive material is at 25° C.
124 . The semiconductor processing method of claim 110 , wherein the carrier has a modulus of elasticity of at least 20 GPa.
125 . The semiconductor processing method of claim 110 , wherein the carrier comprises a crystalline material.
126 . The semiconductor processing method of claim 125 , wherein the crystalline material is a polycrystalline material.
127 . The semiconductor processing method of claim 110 , wherein the carrier has a thickness of about 800 μm or more.
128 . The semiconductor processing method of claim 110 , wherein a coefficient of thermal expansion (CTE) of the carrier is greater than a CTE of the substrate at 25° C.
129 . The semiconductor processing method of claim 110 , wherein fracturing the substrate along or proximate to the damage region to yield a bonded assembly comprises one or more of:
application of ultrasonic energy to at least one of the carrier or the substrate; or
applying a mechanical force to the carrier.