Gas distribution showerhead
First Claim
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1. A gas distribution face plate comprising:
- a face plate body having a thickness defining a number of inlet orifices having a width and a depth, at least one of the number, the width, and the depth configured to create a uniform pressure drop of between about 0.8 and 1 Torr across edge and center regions of the faceplate as gas is flowed through the inlet orifices, whereby a thickness of material deposited at an edge of a wafer varies by 3% or less from a thickness of material deposited at a center of the wafer, when the wafer is separated from the face plate by a gap of between about 75 and 450 mils.
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Abstract
A gas distribution showerhead is designed to allow deposition of uniformly thick films over a wide range of showerhead-to-wafer spacings. In accordance with one embodiment of the present invention, the number, width, and/or depth of orifices inlet to the faceplate are reduced in order to increase flow resistance and thereby elevate pressure upstream of the faceplate. This elevated upstream gas flow pressure in turn reduces variation in the velocity of gas flowed through center portions of the showerhead relative to edge portions, thereby ensuring uniformity in thickness of film deposited on the edge or center portions of the wafer.
203 Citations
18 Claims
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1. A gas distribution face plate comprising:
a face plate body having a thickness defining a number of inlet orifices having a width and a depth, at least one of the number, the width, and the depth configured to create a uniform pressure drop of between about 0.8 and 1 Torr across edge and center regions of the faceplate as gas is flowed through the inlet orifices, whereby a thickness of material deposited at an edge of a wafer varies by 3% or less from a thickness of material deposited at a center of the wafer, when the wafer is separated from the face plate by a gap of between about 75 and 450 mils. - View Dependent Claims (2, 3, 4, 5)
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6. A method of depositing on a semiconductor wafer, a layer of material having a center-to-edge thickness variation of 3% or less, the method comprising:
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providing a gas distribution faceplate having a thickness and defining a number of inlet orifices having a width and a depth, at least one of the orifice number, width, and depth configured to create a uniform pressure drop of between about 0.8 and 1 Torr as gas is flowed through edge and center regions of the faceplate;
providing a semiconductor wafer separated from the gas distribution faceplate by a gap; and
flowing a gas through the faceplate body and across the gap to deposit the layer of material on the wafer. - View Dependent Claims (7, 8, 9, 10, 11)
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12. A method of promoting deposition of material of uniform center-to-edge thickness on a semiconductor wafer, the method comprising:
constricting a flow of deposition gas through a gas distribution faceplate, such that a resulting pressure drop across the faceplate creates a low pressure region over a wafer, gas velocities in the low pressure region over a wafer center and a wafer edge sufficiently uniform to result in deposition of a layer of material having a center-to-edge thickness variation of 3% or less. - View Dependent Claims (13, 14, 15, 16, 17, 18)
Specification