Method of determining the printability of photomask defects
First Claim
1. A method for determining if defects on a photomask will adversely affect the performance of a semiconductor device on a wafer, said device being created by said photomask through a lithographic process, said method comprising the steps of:
- a) inspecting said photomask to find said defects;
b) analyzing process conditions that cause designed features close to said defects to be printed on said wafer with dimensions which fall within the wafer critical dimension tolerance that is applicable to said designed features;
c) assigning an equivalent critical dimension error to said defects; and
d) comparing said equivalent critical dimension error to a mask critical dimension error tolerance for determining whether said defects will adversely affect the performance of said semiconductor device.
3 Assignments
0 Petitions
Accused Products
Abstract
A method for determining if an undesirable feature on a photomask will adversely affect the performance of the semiconductor integrated circuit device that the mask is being used to create. The method includes inspecting the photomask for undesirable features and analyzing the designed features close to the defects. This analysis is performed on lithographic images that represent the image that is transferred onto the semiconductor wafer by the lithography process. This analysis takes into account the effect of variations that are present in the lithography process. Through knowledge of the effects of variations in mask critical dimension of a feature on the lithographic image of that feature, the analysis results in the assignment of an equivalent critical dimension error to the defect. This equivalent critical dimension error is then compared to the mask critical dimension error specification to determine whether or not the defect will adversely affect the device.
174 Citations
52 Claims
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1. A method for determining if defects on a photomask will adversely affect the performance of a semiconductor device on a wafer, said device being created by said photomask through a lithographic process, said method comprising the steps of:
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a) inspecting said photomask to find said defects; b) analyzing process conditions that cause designed features close to said defects to be printed on said wafer with dimensions which fall within the wafer critical dimension tolerance that is applicable to said designed features; c) assigning an equivalent critical dimension error to said defects; and d) comparing said equivalent critical dimension error to a mask critical dimension error tolerance for determining whether said defects will adversely affect the performance of said semiconductor device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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34. A method for determining if a resolution enhancement feature that is desirable on a photomask will adversely affect the performance of a semiconductor device on a wafer, said device created by said photomask through a lithographic process, said resolution enhancement feature being included on said photomask to improve the ability of another critical feature on said photomask to be printed on said wafer, said method comprising the steps of:
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a) locating said resolution enhancement feature on said photomask; b) analyzing process conditions that result in said critical feature close to said resolution enhancement feature to be printed on said wafer with dimensions which fall within the wafer critical dimension tolerance that is applicable to said critical feature; c) assigning an equivalent critical dimension error to said resolution enhancement feature; and d) comparing said equivalent critical dimension error to a mask critical dimension error tolerance for determining whether said resolution enhancement feature adversely affects said semiconductor device. - View Dependent Claims (35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47)
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48. A method for determining if a feature that is desirable on a photomask will adversely affect the performance of a semiconductor device on a wafer, said device created by said photomask through a lithographic process, said method comprising the steps of:
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a) locating said desirable feature on said photomask; b) analyzing process conditions that result in said desirable feature to be printed on said wafer with dimensions that fall within the wafer critical dimension tolerance that is applicable to said feature; c) assigning an equivalent critical dimension error to said feature, wherein said equivalent critical dimension error compares the variation of said desirable feature to a critical dimension variation of another reference feature; and d) comparing said equivalent critical dimension error to a mask critical dimension error tolerance for determining whether said desirable feature adversely affects said semiconductor device. - View Dependent Claims (49, 50, 51, 52)
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Specification