Resistance heater
A heater has a smooth heating surface and a recess formed on a second surface opposite to the heating surface. The recess is formed between opposite side walls in a lengthwise direction of the heater. Formation of the recess improves the electrical resistance of the heater and the opposite side walls reinforce the heater and prevent deformation of the heater when it is subjected to high temperatures in a semiconductor wafer processing device. The heater has substantially the same width along its lengthwise direction. This improves the control of heat pattern design, because the terminal end portions do not have an expanded shape.
1. A heater comprising a body having a smooth and flat heating surface and a recess formed on a surface opposite to the heating surface so as to provide a U shaped cross-section along at least a portion of the body, said body having first and second opposite end portions, wherein said body includes vertical side walls which are spaced apart so as to define said recess except at the opposite end portions, and said vertical side walls extend in a lengthwise direction of the heater between the end portions, and further wherein the body is spiral shaped.
2. The heater according to claim 1 wherein the body has a substantially uniform width along its entire length.
3. The heater of claim 1 wherein each end portion includes a terminal connecting hole, wherein the end portions have substantially identical width to a heating area defined between said opposite end portions, and said recess is formed on said opposite surface except at said opposite end portions.
4. The heater of claim 1 wherein said body is fabricated from graphite or a ceramic material.
5. The heater of claim 1 wherein the body is coated with pBN or SiC.
6. A method for processing a semiconductor wafer comprising the steps of:
a) providing a heater having a body having a smooth and flat heating surface and a recess formed on a surface opposite to the heating surface so as to provide a U-shaped cross-section along at least a portion of the body, said body having first and second opposite end portions, wherein said body includes vertical side walls which are spaced apart so as to define said recess, and said vertical side walls extend in a lengthwise direction of the heater between the end portions, and further wherein the body is spiral shaped;
b) supporting a semiconductor wafer on said heating surface;
c) applying an electric current to said heater; and
d) heating the semiconductor wafer to a predetermined temperature.
7. The method of claim 6 wherein said body includes said vertical side walls which are spaced apart so as to define said recess, except at the opposite end portions.
8. The method of claim 6 wherein each end portion includes a terminal connecting hole, wherein the end portions have substantially identical width to a heating area defined between said opposite end portions, and said recess is formed on said surface opposite the heating surface except at said opposite end portions.
9. The method of claim 6 wherein said body is fabricated from graphite or a ceramic material.
10. The method of claim 6 wherein the body is coated with pBN or SiC.