Real-time prediction of and correction of proximity resist heating in raster scan particle beam lithography
AssigneeApplied Materials, Inc.
InventorsRobert Innes, Sergey Babin, Robin Teitzel, Lee Veneklasen
Life of this patent
Estimating the term…
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.
Claims20
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.
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.
A method, comprising:
- 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.
Dependencies are inferred from the claim text.