Susceptor for heat treatment and heat treatment apparatus
View Patent ↗A susceptor for holding a semiconductor wafer to be flash-heated by a flash of light emitted from flash lamps is formed of transparent quartz. The susceptor has a backside surface only which is roughened by shot blasting to provide a ground-glass-like surface. When a flash of light is emitted, part of the flash of light emitted from the flash lamps and passing by a peripheral portion of the semiconductor wafer held by the susceptor into the susceptor reaches the ground-glass-like backside surface and is diffusely reflected therefrom. Part of the diffusely reflected light impinges on the peripheral portion of the semiconductor wafer held by the susceptor to thereby heat the low temperature regions which have appeared in the peripheral portion of the semiconductor wafer.
1. A heat treatment apparatus for exposing a substrate to light to heat the substrate, comprising:
a chamber for receiving a substrate therein;
a susceptor having a frontside surface and a backside surface for holding the substrate on the frontside surface thereof within said chamber, said susceptor being formed of a transparent material, wherein only a region of the backside surface of said susceptor reached by light emitted from the light source and passing by the substrate held by said susceptor into said susceptor has a rough surface, and
a light source for emitting light to expose the substrate held by said susceptor to the light, wherein the rough surface of the backside surface of the susceptor is of a degree of roughness such that light passing by a peripheral portion of the substrate during heat treatment of the substrate is diffusely reflected from the backside surface, with part of the diffusely reflected light impinging on the peripheral portion of the substrate.
2. The heat treatment apparatus according to claim 1 , wherein said light source includes a flash lamp for emitting a flash of light.
3. The heat treatment apparatus according to claim 2 , further comprising a hot plate for placing said susceptor thereon to preheat the substrate through said susceptor before said flash lamp emits a flash of light.
4. The heat treatment apparatus according to claim 1 , wherein the frontside surface of said susceptor is a smooth surface.
5. The heat treatment apparatus according to claim 1 , wherein said susceptor is made of quartz.
6. A heat treatment susceptor for holding a substrate to be heat-treated by being exposed to light during heat treatment, comprising:
a main body part having a frontside surface and a backside surface, said main body part being formed of a transparent material; and
a holding part formed on the frontside surface of said main body part for holding a substrate,
said backside surface of said main body part having a degree of roughness greater than that of the frontside surface; wherein
only a region of the backside surface of said main body part reached by light emitted and passing by the substrate held by said heat treatment susceptor into said heat treatment susceptor is a rough surface of a degree of roughness such that light passing by a peripheral portion of the substrate during heat treatment of the substrate is diffusely reflected from the backside surface, with part of the diffusely reflected light impinging on the peripheral portion of the substrate.
7. The heat treatment susceptor according to claim 6 , wherein the frontside surface of said main body part is a smooth surface.
8. The heat treatment susceptor according to claim 6 , wherein said main body part is made of quartz.
9. The heat treatment apparatus according to claim 1 , wherein the roughness of the rough surface of the backside surface is of an extent such that said diffusely reflected light from the backside surface with part of the diffusely reflected light impinging on the peripheral portion of the substrate is sufficient to increase uniformity of a temperature distribution of the substrate and the peripheral portion of the substrate during the heat treatment.
10. The heat treatment susceptor according to claim 6 , wherein the roughness of the rough surface of the backside surface is of an extent such that said diffusely reflected light from the backside surface, with part of the diffusely reflected light impinging on the peripheral portion of the substrate, is sufficient to increase uniformity of a temperature distribution of the substrate and the peripheral portion of the substrate during the heat treatment.