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US-12626428-B2 - Drawing data examination method for examining drawing data of a figure expressed by a B-spline curve, drawing method, drawing apparatus, and non-transitory storage medium

US12626428B2US 12626428 B2US12626428 B2US 12626428B2US-12626428-B2

Abstract

A drawing data examination method acquires coordinates representing the positions of a first control point group forming a B-spline curve; calculates a B-spline curve intersection ratio; converts the coordinates of the first control point group into the coordinates of a second control point group of a Bezier curve when the B-spline curve intersection ratio exceeds a threshold value, and determines whether the figure after the coordinate conversion has an intersection; and determines whether the figure of the drawing data has an intersection based on the first control point group when the B-spline curve intersection ratio is equal to or smaller than the threshold value, and converts the coordinates of the first control point group into the coordinates of the second control point group when the figure of the drawing data has an intersection, and determines whether the figure after the coordinate conversion has an intersection.

Inventors

  • Kenichi Yasui

Assignees

  • NUFLARE TECHNOLOGY, INC.

Dates

Publication Date
20260512
Application Date
20240520
Priority Date
20230529

Claims (5)

  1. 1 . A drawing data examination method for examining drawing data being used in a charged particle beam drawing apparatus, by a computer, the drawing data expressing a plurality of drawing figures by a B-spline curve connecting a plurality of first control points with line segments, the coordinate positions of the first control points are set in a two-dimensional coordinate system for each of the plurality of the drawing figures, the drawing data examination method comprising: acquiring coordinate positions of the plurality of the first control points in a two-dimensional coordinate system; calculating a B-spline curve intersection ratio indicating a ratio of the number of the drawing figures expressed by a B-spline curve having an intersection place relative to the total number of the drawing figures to be examined; converting the coordinate positions of the plurality of the first control points into coordinate positions of a plurality of second control points of a Bezier curve using a predetermined conversion matrix in a case where the B-spline curve intersection ratio exceeds a threshold value and determining whether the drawing figures expressed by the Bezier curve have an intersection; and determining whether the drawing figures expressed by the B-spline curve have an intersection based on the plurality of the first control points in a case where the B-spline curve intersection ratio is equal to or smaller than the threshold value, and converting the coordinates positions of the first control points into the coordinate positions of the second control points using a predetermined conversion matrix in a case where the drawing figures have an intersection and determining whether the drawing figures expressed by the Bezier curve have an intersection.
  2. 2 . The drawing data examination method according to claim 1 , wherein a first conversion matrix has a coefficient of a fraction and the coordinates of the first control point group are converted into the coordinates of the second control point group by using a second conversion matrix that is an integer multiple of the first conversion matrix corresponding to the denominator of the fraction of the coefficient.
  3. 3 . A drawing method of emitting a charged particle beam based on drawing data examined by the drawing data examination method according to claim 1 .
  4. 4 . A drawing apparatus comprising: processing circuitry configured to: examine drawing data expressing a plurality of drawing figures by a B-spline curve connecting a plurality of first control points with line segments, the positions of the first control points are set in a two-dimensional coordinate system for each of the plurality of the drawing figures; acquire coordinate positions of the plurality of the first control points in a two-dimensional coordinate system; calculate a B-spline curve intersection ratio indicating a ratio of the number of the drawing figures expressed by a B-spline curve having an intersection place relative to the total number of the drawing figures to be examined; convert the coordinate positions of the plurality of the first control points into coordinate positions of a plurality of second control points of a Bezier curve using a predetermined conversion matrix in a case where the B-spline curve intersection ratio exceeds a threshold value, and determine whether the drawing figures expressed by the Bezier curve have an intersection; and determine whether the drawing figures expressed by the B-spline curve have has an intersection based on the plurality of the first control points in a case where the B-spline curve intersection ratio is equal to or smaller than the threshold value, and convert the coordinate positions of the first control points into the coordinate positions of the second control points using a predetermined conversion matrix in a case where the drawing figures have an intersection and determine whether the figures expressed by the Bezier curve have an intersection.
  5. 5 . A non-transitory storage medium storing a computer program for causing a computer to execute: processing of acquiring coordinate positions of a plurality of first control points in a two-dimensional coordinate system forming a B-spline curve connecting the plurality of first control points with line segments and expressing a plurality of drawing figures of drawing data used by a charged particle beam drawing apparatus; processing of calculating a B-spline curve intersection ratio indicating a ratio of the number of the drawing figures expressed by a B-spline curve having an intersection place relative to the total number of the drawing figures to be examined; processing of converting the coordinates positions of the plurality of the first control points into coordinate positions of a plurality of second control points of a Bezier curve using a predetermined conversion matrix in a case where the B-spline curve intersection ratio exceeds a threshold value, and determining whether the drawing figures expressed by the Bezier curve have an intersection, and determining whether the drawing figures have an intersection based on the plurality of the first control points in a case where the B-spline curve intersection ratio is equal to or smaller than the threshold value; and processing of determining whether the drawing figures expressed by the B-spline curve have an intersection based on the plurality of the first control points in a case where the B-spline curve intersection ratio is equal to or smaller than the threshold value, and converting the coordinate positions of the first control points into the coordinate positions of the second control points using a predetermined conversion matrix in a case where the drawing figures have an intersection and determining whether the drawing figures expressed by the Bezier curve have an intersection.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2023-087886, filed on May 29, 2023; the entire contents of which are incorporated herein by reference. FIELD The present invention relates to a drawing data examination method, a drawing method, a drawing apparatus, and a non-transitory storage medium. BACKGROUND For example, a multibeam drawing apparatus configured to emit a large number of beams at a time by using multiple beams is known as an electron beam drawing apparatus. The multibeam drawing apparatus performs electron beam drawing based on drawing data. In a case where the drawing data includes a curved figure, the curved figure is approximated to a B-spline curve as one of parameter curves for mask data amount reduction. For efficiency of rasterization processing, it is assumed that a curved figure produced with a B-spline curve does not have an intersection within the same figure. Thus, it is needed to examine whether an intersection place exists inside a curved figure of drawing data. In a case where drawing data including a curved figure produced with a B-spline curve is examined, it is potentially determined that the drawing data fails the examination even in a situation where the curve does not have an intersection at all, depending on the shape of the drawing data. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a multi-charged particle beam drawing apparatus according to a first embodiment; FIG. 2 is a diagram illustrating an example of design data D0; FIG. 3 is a flowchart for describing an example of the procedure of a drawing data examination method; FIG. 4 is a diagram illustrating an example of control points of a B-spline curve and a Bezier curve; FIG. 5 is a diagram for describing an example of the drawing data examination method; FIG. 6 is a flowchart for describing another example of the procedure of the drawing data examination method; FIG. 7 is a diagram for describing the drawing data examination method performed in accordance with the flowchart illustrated in FIG. 6; FIG. 8 is a diagram illustrating an example of control points of a B-spline curve and a Bezier curve according to a first modification; FIG. 9 is a diagram illustrating design data according to a second modification; FIG. 10 is a flowchart for describing an example of the procedure of a drawing data examination method according to the second modification; and FIG. 11 is a block diagram illustrating a schematic configuration of a drawing data examination apparatus according to a second embodiment. DETAILED DESCRIPTION Embodiments will now be explained with reference to the accompanying drawings. The present invention is not limited to the embodiments. A drawing data examination method according to an aspect of the present invention is a drawing data examination method for examining drawing data of a figure expressed by a B-spline curve, the drawing data being used by a charged particle beam drawing apparatus. The examination method acquires coordinates representing the positions of a first control point group forming a B-spline curve; calculates, in a process of examination, a B-spline curve intersection ratio indicating a ratio of the number of figures expressed by a B-spline curve having an intersection place relative to the total number of figures; converts the coordinates of the first control point group into coordinates of a second control point group of a Bezier curve in a case where the B-spline curve intersection ratio exceeds a threshold value, and determines whether the figure after the coordinate conversion has an intersection; and determines whether the figure has an intersection based on the first control point group in a case where the B-spline curve intersection ratio is equal to or smaller than the threshold value, and converts the coordinates of the first control point group into the coordinates of the second control point group in a case where the figure has an intersection, and determines whether the figure after the coordinate conversion has an intersection. First Embodiment FIG. 1 is a schematic diagram of a multi-charged particle beam drawing apparatus according to a first embodiment. In the present embodiment, a configuration in which an electron beam is used as an example of a charged particle beam will be described below. However, a charged particle beam is not limited to an electron beam but may be another charged particle beam such as an ion beam. Moreover, a drawing apparatus is of a multibeam scheme in the present embodiment but may be of a single beam scheme. A drawing apparatus 1 according to the present embodiment, which is illustrated in FIG. 1 includes a drawer 10 configured to draw a desired pattern by irradiating a target object such as a mask or a wafer with an electron beam, and a controller 50 configured to control drawing operation of the drawer 10. The drawer 10 incl