Method and system for generating a bit pattern

• US 5,404,410 A
• Filed: 01/10/1994
• Issued: 04/04/1995
• Est. Priority Date: 05/31/1990
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation), Toshiba Corporation
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Yoshikawa, Ryoichi, Tsuchiya, Hideo, Yamashita, Kyoji, Tojo, Toru, Tabata, Mitsuo
• Primary Examiner(s): Couso, Jose L.
• Application Number:
  US08/180,813
• Time in Patent Office: 449 Days
• Field of Search: 382/8, 382/47, 382/50-54, 358/459, 358/466
• US Class Current: 382/144
• CPC Class Codes: G06T 2207/30148 Semiconductor; IC; Wafer
• CPC Class Codes: G06T 7/001 using an image reference approach

Abstract

A pattern defect inspection apparatus according to this invention comprises an irradiation circuit for irradiating a substrate on which a given pattern is drawn, a detector circuit for detecting said irradiated pattern on said substrate, a bit pattern generating circuit for quantizing and generating previously given design data by processing said design data based on specified figure information to obtain bit pattern data composed of a finite number of pixels, and a comparator circuit for detecting defects on said substrate by comparing the detected data from said detecting means with the data from said bit pattern generating means, wherein the bit pattern generating circuit has an additional parameter conditioner for setting the dimension of each pixel to be quantized into said bit pattern data to the desired value.

Claims

1. A system for checking a defect in a figure pattern which is formed on a photomask used for manufacturing a semiconductor integrated circuit element, said figure pattern being defined by predetermined parameters and having predetermined bit dimensions, said system comprising:

memory means for storing design data which indicates a figure pattern defined by predetermined parameters and having predetermined bit dimensions;

a table on which the photomask is placed;

a driving mechanism for moving the table in X- and Y-directions;

control means for controlling the driving mechanism;

a light source for emitting light to the photomask;

an optical system for optically processing light which has been transmitted through the photomask;

photodetector means for detecting light output from the optical system so as to obtain bit patterns representing the figure pattern formed on the photomask;

conditioning means for conditioning parameters of the design data on the basis of a predetermined inspection magnification β

, a magnification difference Δ

β

between the figure pattern indicated by the design data and the figure pattern formed on the photomask, and a scaling factor K;

developing means for developing the design data into elemental figure data on the basis of the parameters conditioned by the conditioning means;

a bit pattern generator for generating bit patterns which define the elemental figure data, on the basis of the elemental figure data obtained by the developing means;

comparison means for comparing, in units of one bit, the bit patterns generated by the generating means and the bit patterns obtained by the photodetector means;

determination means for determining whether or not the figure pattern formed on the photomask is defective on the basis of comparison results obtained by the comparison means; and

output means for outputting data representing the presence of a defective bit pattern when the determination means determines that the figure pattern on the photomask is defective.

2. A system for checking a defect in a figure pattern which is formed on a photomask used for manufacturing a semiconductor integrated circuit element, said figure pattern being defined by predetermined parameters and having predetermined bit dimensions, said system comprising:

memory means for storing design data which indicates a figure pattern defined by predetermined parameters and having predetermined bit dimensions;

a table on which the photomask is placed;

a driving mechanism for moving the table in X- and Y-directions;

control means for controlling the driving mechanism;

a light source for emitting light to the photomask;

an optical system for optically processing light which has been transmitted through the photomask;

photodetector means for detecting light output from the optical system so as to obtain bit patterns representing the figure pattern formed on the photomask;

quantization means for quantizing elemental figures which are represented by the design data read out from the memory means;

conversion means for converting bit dimensions of the element figures quantized by the quantizing means into bit dimensions which coincide with bit dimensions of the figure pattern represented by the light detected by the photodetector means;

developing means for developing the elemental figures quantized by the quantization means into bit patterns;

comparison means for comparing, in units of one bit, the bit patterns obtained by the developing means and the bit patterns obtained by the photodetector means;

determination means for determining whether or not the figure pattern formed on the photomask is defective on the basis of comparison results obtained by the comparison means; and

output means for outputting data representing the presence of a defective bit pattern when the determination means determines that the figure pattern on the photomask is defective.

3. The system according to claim 2, wherein said conversion means includes means for varying a magnification of the bit dimensions of the elemental figures such that the bit dimensions of the element figures quantized by the quantizing means coincide with the bit dimensions of the figure pattern represented by the light detected by the photodetector means.

4. The system according to claim 2, wherein said conversion means includes means for allocating a fraction, which is data on less than one pixel and is produced when the elemental figures are quantized by the quantizing means, to predetermined bit pattern data on the basis of at least one of rounding-up, rounding-down and rounding-off results obtained with respect to the fraction.

5. The system according to claim 2, wherein said conversion means includes means for dividing the elemental figures quantized by the quantizing means into a plurality of elemental figures which are connected to one another by means of boundary segments.