Real-time prediction of and correction of proximity resist heating in raster scan particle beam lithography
First Claim
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1. A method for correcting for proximity heating of resist in an electron beam lithography system, comprising:
- determining an increase of temperature at a writing point by grouping past pixel values as cells of varying size and using resulting cell values as scalar products with one or more predetermined kernels.
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Abstract
The present invention relates to methods of predicting proximity heating of resists in electron beam lithography in real-time as the writing proceeds enabling beam compensation in current and/or dwell time to be performed during writing. A method of using a precomputed kernel capable of proximity resist temperature evaluation in real-time as beam writing proceeds by scalar product of the kernel with a graded cell size coverage map. A shifted impulse response function is shown to give the kernel values accurate to within a few percent.
44 Citations
17 Claims
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1. A method for correcting for proximity heating of resist in an electron beam lithography system, comprising:
determining an increase of temperature at a writing point by grouping past pixel values as cells of varying size and using resulting cell values as scalar products with one or more predetermined kernels. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A system, comprising:
a lithographic printing machine; and
one or more control processors, said one or more processors adapted to compensate for proximity resist heating by applying a kernel of values to one or more cells of pixels to determine a temperature effect of previously written pixels on a current writing pixel for determining the exposure compensation necessary to compensate for the temperature change on the lithographic quality due to earlier writing.- View Dependent Claims (8, 9, 10)
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11. A method, comprising:
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determining a set of kernel values by solving a thermal diffusion equation for a plurality of cells of varying size, said cells comprising groupings of pixels assumed to have a uniform distribution of values within said cells;
applying resulting kernel values during writing to a coverage map arranged as said plurality of cells. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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Specification