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US 2011/0035171 A1Published application
Calibration of Optical Line Shortening Measurements
AssigneeInfineon Technologies AG
InventorDavid Ziger
Life of this patent
Estimating the term…
Abstract
A system and method of calibrating optical line shortening measurements, and lithography mask for same. The lithography mask comprises a plurality of gratings, with a calibration marker disposed within each grating. The mask is used to pattern resist on a semiconductor wafer for purposes of measuring and calibrating line shortening. The pattern on the wafer is measured and compared to measurements made of the pattern on the mask. The difference gives the amount of line shortening due to flare, and may be used to calibrate line shortening measurements made using optical measurement tools.
Claims20
A system for calibration of line shortening measurements, the system comprising:
- a semiconductor workpiece support for supporting a semiconductor workpiece having a layer of photosensitive material;
- at least one mask, the at least one mask comprising a first test pattern and a second test pattern disposed proximate a portion of the first test pattern, the first test pattern comprising a plurality of gratings and the second test pattern comprising an opaque or attenuated region, wherein a calibration marker is disposed within at least one of the gratings;
- an exposure tool for exposing the layer of photosensitive material to energy through the at least one mask;
- a developing tool for developing the layer of photosensitive material;
- at least one measurement tool for measuring features formed on the photosensitive material by the first test pattern proximate the second test pattern to determine a first line shortening measurement, for measuring the length of at least one grating of the first test pattern of the at least one mask, for measuring a first side of the at least one grating formed by the at least one grating of the first test pattern on the photosensitive material between a calibration marker and an end of the grating, and for measuring a second side of the at least one grating formed by the at least one grating of the first test pattern on the photosensitive material between the calibration marker and the other end of the grating;
- and
- a processor adapted to determine a difference D1 of the first side measurement and the mask measurement, a difference D2 of the second side measurement and the mask measurement, and a difference D3 of D1 and D2 to determine a second line shortening measurement, and adapted to compare the second line shortening measurement to the first line shortening measurement to determine a calibration factor for line shortening measurements.
4 more elements
A lithography system comprising:
- a semiconductor workpiece support for supporting a semiconductor workpiece having a layer of photosensitive material;
- a lithography mask comprising a transparent substrate and an opaque material disposed on the substrate, the opaque material comprising a first test pattern, the first test pattern comprising a plurality of gratings arranged in a column or row, each of the gratings comprising a calibration marker disposed therein, wherein each calibration marker of each grating is located at a position between a first end and a second end of each grating, and wherein the position of each calibration marker is different than the position of every other calibration marker of the other gratings in the column or row;
- and
- an exposure tool for exposing the layer of photosensitive material to energy through the lithography mask.
1 more element
A lithography system comprising:
- a semiconductor workpiece support for supporting a semiconductor workpiece having a layer of photosensitive material;
- a lithography mask comprising
- (a) a transparent substrate,
- (b) a flare sensitive first test pattern disposed on a first region of the transparent substrate, the flare sensitive first test pattern defining a first area having a first and a second dimension and comprising a plurality of parallel gratings arranged in one of rows and columns and each of said plurality of parallel gratings having a length the same as one of said first and second dimensions,
- (c) calibration markers disposed within each of the plurality of parallel gratings, wherein each calibration marker of each grating is located at a position between a first end and a second end of each grating, and wherein the position of each calibration marker is different than the position of every other calibration marker of the other gratings in the column or row, and
- (d) a second test pattern disposed on a second region of the transparent substrate, said second test pattern comprising an opaque or attenuated region located proximate a portion of the flare sensitive first test pattern;
- and
- an exposure tool for exposing the layer of photosensitive material to energy through the lithography mask.
5 more elements
Dependencies are inferred from the claim text.