JP6074801B2 - Electron beam exposure method - Google Patents

Description

  The present invention relates to an electron beam drawing data creation apparatus and method for creating drawing data necessary for executing drawing by an electron beam drawing apparatus from design layout data of a semiconductor device and an optical element, and more particularly, variable shaped electron beam exposure. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for creating drawing data and a program for realizing them on a computer.

  In recent years, with the development of optical communication technology, development of devices for optical communication has been actively performed. In these optical communication devices, an optical wiring technique for wiring various functional elements and an optical waveguide technique for multiplexing, demultiplexing, and switching a large number of lights are very important basic technologies.

  Here, the main characteristics required for these optical communication devices are low optical loss and controllability of refractive index. Among the above, in order to realize a low optical loss, it is necessary to suppress the optical loss caused by the minute unevenness formed on the side surface of the optical waveguide and the deviation between the pattern elements when the optical waveguide circuit is manufactured.

  A characteristic of these optical waveguides is that a curved pattern such as an arc is frequently used to bend light.

  In addition, the microfabrication technology cultivated by semiconductor manufacturing technology such as CMOS is used for manufacturing these optical communication devices. Among the microfabrication technologies, the direct electron beam drawing method, which does not use a photomask and directly draws from a pattern design by an electron beam, is used for research and development applications, etc., because it contributes to reducing the photomask cost and lead time. There are many opportunities.

  Among them, the variable shaped electron beam exposure method is used for low-volume production and research and development due to maskless, relatively high drawing speed, fine processing performance, and the like.

  Conventionally, when an oblique straight line or an arbitrary curve is drawn using a variable shaped electron beam exposure apparatus, the oblique part is divided into thin strip-like minute rectangles, and the straight line or the curve is approximated and drawn. . For this reason, the increase in the drawing time due to the increase in the number of drawing rectangles and the minute unevenness of the pattern contour caused by the curve approximation using the minute rectangles have been problems.

  In order to solve this problem, there has been proposed a method of generating straight line or curved line drawing data of an arbitrary angle by rectangular decomposition processing for pattern data to be drawn.

  As a specific rectangular decomposition process, in FIG. 1, a curve approximation method by introducing trapezoidal templates 2 and 3 (Patent Document 1), and in FIG. A method of reducing (Patent Document 2) or a method of changing both the drawing method between the pattern internal structure 5 and the outer edge structure 6 in FIGS. Patent Documents 3 and 4) have been proposed.

JP-A-5-145549 Electron beam exposure method JP-A-6-20931 Electron beam exposure method JP2008-292871DRAWING DATA CREATION METHOD AND DRAWING METHOD JP-A-10-209000 Electron beam drawing apparatus and pattern drawing method

  However, in the variable shaped electron beam exposure method, the beam trajectory spreads out of focus due to the Coulomb repulsion acting between electrons in the electron beam in proportion to the rectangular shaped beam irradiation area, resulting in a beam focusing position. There is a fundamental error generation factor that causes a shift of the pattern size, that is, a shift of the pattern size.

  The change in the pattern size to be drawn due to this beam focusing deviation is substantially proportional to the rectangular shaped beam irradiation area when the beam current density is constant.

  At this time, as shown in FIG. 5A, in the case of a pattern arrangement in which a large-area drawing rectangle 51 and a small-area drawing rectangle 52 are adjacent to the design data 53 to be obtained, the rectangular data size The actual pattern size divergence, that is, the dimension error, differs between the large area pattern and the minute area pattern.

  Therefore, since the large area pattern portion 54 is drawn as a larger area as shown in FIG. 5B, the outer edge figure of the actually drawn pattern is drawn with respect to the design data 53 to be obtained. The unevenness of the part is emphasized.

  Therefore, the drawing method of an arbitrary curve using a rectangle in which various pattern sizes are mixed has been an obstacle in realizing reduction of minute unevenness due to the above-described error factors.

  In view of such problems, the present invention is to provide a data generation method for electron beam exposure that can draw a smooth arbitrary curve using a variable shaped beam exposure apparatus.

  The present invention first provides the following drawing data creation and drawing method.

(1) In a drawing pattern data generation method for a drawing apparatus that draws an exposure pattern based on design layout data using an electron beam,
An arbitrary angle containing region extracting step for extracting a region 61 including an arbitrary angle side or an arbitrary curve in the design layout data;
An internal rectangle data creating step for extracting the internal rectangle 62 inscribed in the outer edge of one or a plurality of the arbitrary angle-containing regions with respect to the arbitrary angle-containing region, and generating the drawing pattern data;
An internal rectangle obtained by reducing and removing the inscribed internal rectangle 62 by extracting and removing the intermediate connection rectangle 63 having a minute width: W inscribed in the outer edge of the internal rectangle 62 inscribed in the outer edge of the one or more arbitrary angle-containing regions 61 Intermediate connection rectangle data creation step for generating drawing pattern data of 65 and intermediate connection rectangle 63;
With respect to the area excluding the rectangle 62 inscribed in the outer edge of the one or more arbitrary angle-containing areas from the arbitrary angle-containing area 61, the one or more arbitrary angle-containing areas inscribed in the outer edge of the area An edge rectangle data creation step for extracting the minute rectangle 64 (border rectangle) of the minute width: W circumscribing the inner rectangle inscribed in the outer edge of the edge and generating drawing pattern data;
Drawing the exposure pattern of the arbitrary angle containing region using the reduced drawing pattern data of the inner rectangle 65 and the intermediate connection rectangle 63 and the drawing pattern data of the outline rectangle 64 having substantially the same area as the intermediate connection rectangle 63 ; ,
A drawing pattern data generation method characterized by comprising:

  With the above-described means, in the present invention, the large area pattern portion is not directly arranged on the outer edge of the exposure pattern, but the smooth irregular arbitrary curve with the minute unevenness reduced by the intermediate connection rectangle having a size substantially equal to the border rectangle. It became possible to draw.

The present invention is then
(2) The drawing pattern data generation method for the drawing apparatus using an electron beam as described above, wherein the drawing pattern data are all created as variable shaped beam data,
I will provide a.

The present invention also provides
(3) A drawing apparatus using an electron beam, wherein the drawing data of the drawing apparatus is generated by the drawing pattern data generation method according to any one of claims 1 and 2. Drawing apparatus using,
I will provide a.

Finally, the present invention
(4) A program for generating drawing pattern data in a drawing apparatus using an electron beam, wherein the drawing pattern data generation method according to any one of claims 1 to 2 is executed. A program that generates pattern data,
I will provide a.

  In the conventional drawing data creation method, as shown in FIG. 8A, drawing data is generated by a combination of two types of data of internal rectangular data having a large beam area and bordering rectangular data having a small beam area.

  For this reason, as shown in FIG. 8B, the deviation from the design dimension values of the internal rectangular data and the bordered rectangular data is different due to the spread of the beam size due to the focus shift depending on the rectangular shaped beam irradiation area. This has led to the deviation of the pattern size from the design dimension, and in turn, the generation of minute irregularities on the side of the pattern.

  However, according to the drawing data creation method of the present invention, as shown in FIG. 9, there is intermediate connection rectangular data having a beam area substantially equal to the edge rectangle so as to surround the outer edge of the inner rectangle data. In addition, it is possible to suppress the deviation from the design dimensions of the intermediate connection rectangle and the outline rectangle pattern size located in the vicinity of the pattern outer edge, and hence the occurrence of minute irregularities on the side surface of the pattern.

It is a figure showing the rectangle decomposition | disassembly process by the trapezoid template of a curve approximation method. It is a figure showing the rectangular decomposition | disassembly process of the method of reducing the micro unevenness | corrugation using energy distribution. It is a figure showing the rectangular decomposition process of the method of changing the drawing method with a pattern internal structure and an outer edge structure, respectively, and making a high-speed of drawing and reduction of micro unevenness | corrugation compatible. It is a figure showing the rectangular decomposition | disassembly process of the method of changing the drawing method by the pattern internal structure and the outer edge structure 6, respectively, and making high-speed drawing and reduction of micro unevenness | corrugation compatible. It is the figure which modeled generation | occurrence | production of the micro unevenness | corrugation by the drawing method of the arbitrary curve using the rectangle in which large and small various pattern sizes are mixed. It is the figure which modeled the outline | summary of the rectangle decomposition | disassembly process by the drawing data generation method by this invention. It is a flowchart showing the outline | summary (step) of the rectangle decomposition | disassembly process of the drawing data generation method by this invention. It is the figure which modeled generation | occurrence | production of the micro unevenness | corrugation by the drawing method of the arbitrary curve using the rectangle in which large and small various pattern sizes are mixed. It is a figure showing the result of the rectangle decomposition | disassembly process by the drawing data generation method by this invention.

An embodiment for carrying out the present invention will be described with reference to a schematic diagram of a rectangular division process in FIG. 6 and a flowchart of a drawing data generation method in FIG.
In the present invention, in order to solve the above-mentioned problem, graphic data including a straight line including an arbitrary angle or an arbitrary curved line is extracted from design layout data (graphic data) including a straight line or an arbitrary curved line having an arbitrary angle (step 1 This is divided into the following three parts.

  First, as shown in FIG. 6A, a plurality of internal rectangles 62 that are inscribed in a range that does not affect the pattern edge portion with respect to the outer edge of the graphic data 61 including an arbitrary angle or an arbitrary curve are generated (step 2).

After that, as shown in FIG. 6-2, inside the plurality of internal rectangles 62, an intermediate connection rectangle 63 formed with a minute width: W, which is inscribed to the outer edge of the rectangle: 62, is filled (step 3). .
Thereby, the internal rectangle 62 having a large pattern area is divided into an internal rectangle 65 and an intermediate connection rectangle 63 which are reduced in size.

  After that, as shown in FIG. 6C, an edge rectangle 64 is generated so as to be inscribed in the graphic data 61 including an arbitrary angle or an arbitrary curve and to be edged with a minute width: W on the outer periphery of the intermediate connection rectangle 63. (Step 4).

  Drawing data generated by the above-described method: FIG. 6-3 shows that the inner rectangle 62 having a large pattern area is reduced to the inner rectangle 65 which is smaller than that in the outer edge region of a straight line or an arbitrary curve including an arbitrary angle where it is desired to reduce minute unevenness. All the outer edges are filled with the intermediate connection rectangle 63 or the edge rectangle 64 formed with the same width: W without being directly exposed to the outer edge of the straight line or the arbitrary curve at any angle.

  When drawing is performed with the drawing data prepared in this way (step 5), the occurrence of irregularities on the outer edge of the pattern due to the pattern size error depending on the rectangular data size specific to the variable shaping electron beam exposure method is suppressed. Therefore, it is possible to provide a method of drawing a smoother arbitrary straight line or arbitrary curved line.

FIG. 7 shows an embodiment of a drawing data creation method and drawing method according to the present invention.
The arbitrary angle region extraction unit 1 (step 1) extracts a region 61 including a straight line including an arbitrary angle or an arbitrary curve from the design data.

  The internal rectangle data creation unit 2 (step 2) generates one or a plurality of rectangles inscribed in the arbitrary angle area extracted in step 1 as the internal rectangle data 62 in the category of the minimum grid specified in advance.

The intermediate connection rectangle data creation unit 3 (step 3) generates intermediate connection rectangle data 63 having a predetermined width W for the outer edge of the inner rectangle generated in step 2.
Thereby, the internal rectangle 62 having a large pattern area is divided into an internal rectangle 65 and an intermediate connection rectangle 63 which are reduced in size.

  The outline rectangle data creation unit 4 (step 4) lays out a minute rectangle having a pattern width: W specified in advance in the area obtained by subtracting the internal rectangle data generated in step 2 from the design data. Pattern edge (outlined rectangle) data 64 in which the edge portion is expressed by a minute width: W is generated.

The pattern drawing execution unit 5 (step 5) executes drawing using the reduced pattern internal rectangle data 65, border rectangle data 64, and intermediate connection rectangle data 63.
When the drawing data creation method of the present invention is actually applied, the approximate dimensions of each figure are as follows: the inner rectangle 62 or 65 has a short side: ~ 500 nm / long side: ~ 500 nm, and the intermediate connection rectangle 63 has a short length. The side: 20 nm / long side: ˜100 nm, and the edge rectangle 64 fell within the short side: 20 nm / long side: ˜50 nm, and the intermediate connection rectangle 63 and the edge rectangle 64 had substantially the same beam area.
In this way, the deviation from the design dimensions of the pattern size of both the intermediate connection rectangle 63 and the border rectangle 64 located in the vicinity of the pattern outer edge, and thus the occurrence of minute irregularities on the pattern outer edge can be suppressed.

  In the drawing pattern data generation method described in the first embodiment, all can be created as variable shaped beam data. The features of this drawing data generation method are maskless, relatively high drawing speed, fine processing performance, etc. Therefore, it can be suitably used in a variable shaped electron beam exposure system suitable for small-scale production and R & D applications.

  The drawing pattern data generation method described in the first embodiment can be implemented in a drawing apparatus using an electron beam, and the features of this drawing data generation method are preferably utilized.

  When the drawing pattern data generation method described in the first embodiment functions in the form of a program in a drawing apparatus using an electron beam, the features of this drawing data generation method are preferably utilized.

DESCRIPTION OF SYMBOLS 1 Diagonal line 2 Trapezoid template 3 Trapezoid template 4 Drawing pattern overlap part 5 High-definition drawing 6 Pattern edge part 51 expressed by a fine grid Internal rectangle 52 inscribed in the area 52 Border rectangle 53 Design data 54 Rectangle actually exposed 61 Arbitrary angle-containing region 62 Internal rectangle 63 inscribed in the arbitrary angle-containing region Intermediate connection rectangle 64 Border rectangle 65 Reduced inscribed internal rectangle

Claims (4)

In a drawing pattern data generation method of a drawing apparatus that draws an exposure pattern based on design layout data using an electron beam,
An arbitrary angle containing region extracting step of extracting an arbitrary angle containing region 61 including an arbitrary angle side or an arbitrary curve in the design layout data;
An internal rectangle data creating step for extracting an internal rectangle 62 inscribed in an outer edge of one or a plurality of the arbitrary angle-containing regions 61 with respect to the arbitrary angle-containing region 61, and generating drawing pattern data;
An internal rectangle obtained by reducing and removing the inscribed internal rectangle 62 by extracting and removing the intermediate connection rectangle 63 having a minute width: W inscribed in the outer edge of the internal rectangle 62 inscribed in the outer edge of the one or more arbitrary angle-containing regions 61 Intermediate connection rectangle data creation step for generating drawing pattern data of 65 and intermediate connection rectangle 63;
With respect to a region excluding the rectangle 62 inscribed in the outer edge of the one or more arbitrary angle-containing regions 61 from the arbitrary angle-containing region 61, the region is inscribed in the outer edge of the region and contains the one or more arbitrary angles An edge rectangle data creation step for extracting the minute rectangle 64 (border rectangle 64) of the minute width: W circumscribing the inner rectangle 62 inscribed in the outer edge of the region 61 and generating drawing pattern data;
A step of drawing an exposure pattern of the arbitrary angle containing region 61 by using the drawing pattern data of the reduced internal rectangle 65 and the intermediate connection rectangle 63 and the drawing pattern data of the outline rectangle 64 having substantially the same area as the intermediate connection rectangle 63. When,
A drawing pattern data generation method characterized by comprising:   2. The drawing pattern data generation method for a drawing apparatus using an electron beam according to claim 1, wherein all of the drawing pattern data are created as variable shaped beam data.   A drawing apparatus using an electron beam, wherein the drawing data of the drawing apparatus is generated by the drawing pattern data generation method according to any one of claims 1 and 2. apparatus.   A drawing pattern data for generating drawing pattern data in a drawing apparatus using an electron beam, wherein the drawing pattern data is generated by executing the drawing pattern data generation method according to claim 1. The program to generate.

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