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.
Claims32
A lithography mask for calibrating line shortening measurements, the mask comprising:
- a transparent substrate;
- and
- an opaque material disposed on the substrate, the opaque material comprising a test pattern, the test pattern comprising a plurality of gratings, at least one of the gratings comprising a calibration marker disposed therein.
6-7. (canceled)
A method of calibrating line shortening measurements, the method comprising:
- providing a workpiece, the workpiece comprising a layer of photosensitive material disposed thereon;
- exposing the layer of photosensitive material to energy through 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 second test pattern comprising an opaque or attenuated region, the first test pattern comprising a plurality of gratings, wherein a calibration marker is disposed within at least one of the gratings;
- developing the layer of photosensitive material;
- measuring features formed on the layer of photosensitive material by the first test pattern proximate the second test pattern to determine a first line shortening measurement;
- determining a second line shortening measurement using the calibration marker;
- and
- comparing the second line shortening measurement to the first line shortening measurement to determine a calibration factor for line shortening measurements.
(canceled)
13-14. (canceled)
(canceled)
A system for calibration of line shortening measurements, the system comprising:
- a semiconductor workpiece, the workpiece comprising a layer of photosensitive material disposed thereon;
- 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 second test pattern comprising an opaque or attenuated region, the first test pattern comprising a plurality of gratings, 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 layer of 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, and for making measurements relative to the calibration marker to determine a second line shortening measurement;
- and
- a processor adapted to compare the second line shortening measurement to the first line shortening measurement to determine a calibration factor for line shortening measurements.
(canceled)
A method of manufacturing a semiconductor device, the method comprising:
- providing a test workpiece having a first layer of photosensitive material formed thereon;
- using a lithography system, exposing the first layer of photosensitive material of the test workpiece to energy through at least one lithography mask, the at least one lithography mask comprising a plurality of test features, at least one of the plurality of test features comprising a calibration marker;
- developing the first layer of photosensitive material of the test workpiece;
- measuring features formed on the first layer of photosensitive material to determine a first line shortening measurement of the lithography system;
- determining a second line shortening measurement of the lithography system using the calibration marker;
- comparing the second line shortening measurement to the first line shortening measurement to determine a calibration factor for line shortening measurements for the lithography system;
- adjusting results of the first line shortening measurement by the calibration factor;
- providing a semiconductor device, the semiconductor device having a second layer of photosensitive material formed thereon;
- using the lithography system to expose the second layer of photosensitive material;
- developing the second layer of photosensitive material;
- and
- using the second layer of photosensitive material to pattern a material layer of the semiconductor device.
Dependencies are inferred from the claim text.