JP2783447B2 - Charged particle beam drawing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a charged particle beam writing method in which a pattern writing time is reduced.

(Prior Art) Recently, as a method for realizing ultra-high density of IC elements, a charged particle beam drawing method such as an electron beam drawing method or an ion beam drawing method has attracted attention.

What can be said as a representative of the charged particle beam drawing method,
For example, there is an electron beam cross section variable type drawing method. This method aims at high-speed and high-precision drawing. The cross-sectional shape and size of the electron beam emitted from the electron beam generating means are reduced by two mask plates having square or rectangular holes and the two mask plates. A variable pattern is formed by an electron beam cross-sectional shape and size changing means comprising an electron lens and a deflector disposed between the plates, and a predetermined pattern is drawn by projecting the formed beam at a predetermined position on a material. ing.

FIG. 2A shows a trapezoidal pattern having an upper base a, a lower base b, and a height c. In addition, for convenience of explanation,
The shorter one is the upper bottom. When such a pattern is drawn by the electron beam variable area drawing method, it is performed as follows.

First, writing when the lower base b of the trapezoid pattern is larger than the slit size of the mask plate (provided that the height c is smaller than the slit size) will be described. In such a case, first, the trapezoid pattern is divided into a rectangular pattern L and triangular patterns M and N (see FIG. 2B).
The rectangular pattern L is obtained by shaping an electron beam into a shape having a shape corresponding to the pattern L by the electron beam cross-sectional shape and size variable cross-section means, and shooting the shaped beam at a predetermined position on a material. Is drawn by
In addition, the triangular patterns M and N respectively transmit an electron beam by the electron beam cross-sectional shape and size variable cross-sectional means.
To sequentially shape the rectangular patterns M ₁ , M ₂ ,..., M ₆ , N ₁ , N ₂ ,..., N ₆ and draw the shaped beams at predetermined positions on the material. (See FIG. 2 (c)). As a result, a trapezoid pattern is drawn.

When the lower base b of the trapezoid pattern is smaller than the slit size of the mask plate (however, the height c is smaller than the slit size), the electron beam is formed by the electron beam cross-sectional shape and size variable cross-section means. sequentially rectangular pattern O _1, O _2, and shaped into dimensions of a shape corresponding to the ...... O _6,
By drawing each of the shaped beams at a predetermined position on the material, a trapezoid pattern is drawn.

(Problems to be Solved by the Invention) There are usually tens of thousands to hundreds of thousands of patterns drawn on one material, and there are extremely many trapezoidal patterns among them. In order to draw these trapezoidal patterns, the electron beam must be sequentially shaped into a rectangular shape many times as described above for each trapezoidal pattern drawing, and the process of sequentially shooting each rectangular beam at a predetermined position must be repeated. . Therefore, the drawing time becomes enormous.

The present invention has been made in view of such a point, and an object of the present invention is to provide a novel charged particle beam drawing method for shortening a drawing time.

(Means for Solving the Problems) In order to achieve this object, the present invention relates to a method for forming a cross section of a charged particle beam into a cross section of a triangular pattern when the base of the triangular pattern or the longer base of the trapezoidal pattern is smaller than a reference dimension. Alternatively, the trapezoidal pattern is shaped into a rectangular shape having two sides each at the bottom and height, and shot at a predetermined position on the material.

(Embodiment) FIG. 1 is a schematic diagram of an electron beam cross-section variable type drawing apparatus shown as one embodiment of a charged particle beam drawing method of the present invention.

In the figure, 1 is a magnetic disk, 2 is a control device, 3 is a figure dividing circuit, 4 is a figure discriminating circuit, 5 is a first rectangular pattern forming circuit, 6 is a comparing circuit, 7 is a second rectangular pattern forming circuit,
8 is a control device, 9 is a drawing data memory, 10 is an electron gun, 11
Is a blanking electrode, 12 is a blanking aperture, 13 and 15 are focusing lenses, 14 is a first mask plate, 16 is an X-direction shaping deflector, 17 is a Y-direction shaping deflector, 18 is a second mask plate, 19 is a projection lens, 20 is an X direction positioning deflector, 21 is a Y direction positioning deflector, 22 is a material, 23 is a drawing time signal generation circuit, 24, 26, 28, and 30 are DA converters, 25 and 27. , 29 and 31 are amplifiers.

In the device configured as described above, FIG.
Is drawn as follows.

First, the control device 2 calls up the graphic data from the magnetic disk 1 in which graphic data based on the trapezoidal pattern shown in FIG. 2A is stored. Then, the graphic data is supplied to the graphic dividing circuit 3. The figure dividing circuit 3 divides a figure only when the received figure data represents a trapezoidal pattern and the length of the bottom of the trapezoidal pattern is larger than the slit size of the mask plates 14 and 18. For example, if the length of the bottom of the trapezoidal pattern is larger than the size of each slit, the figure data representing the trapezoidal pattern sent is a rectangular pattern L and a triangular pattern M as shown in FIG. , N. The graphic data representing the divided rectangular pattern L and the graphic data representing the triangular patterns M and N are supplied to the graphic discriminating circuit 4. The figure determining circuit 4 determines whether the sent figure data represents a rectangular pattern or a triangle or trapezoid pattern. The figure determining circuit determines the figure data representing the rectangular pattern L as a rectangular pattern and supplies the figure data to the control device 8. The controller 8 converts drawing data (drawing position data, drawing time data, and beam size data) of the pattern from the graphic data representing the rectangular pattern L.
Is stored in the drawing data memory 9. Further, graphic data representing the triangular patterns M and N determined as triangular patterns by the determining circuit 4 are supplied to a first rectangular pattern creating circuit 5. The first rectangular pattern creating circuit 5 includes a triangular pattern
When graphic data based on M and N is received, rectangular patterns M ₁ , M ₂ ,... M ₆ , N ₁ , N ₂ ,
... Graphic data representing N ₆ is created, and the respective graphic data are supplied to the comparison circuit 6.

The reference size δ is set in the comparison circuit 6 in advance. As the reference dimension δ, for example, the width (length in the y direction) of a large number of rectangular patterns for drawing a trapezoid pattern or a triangular pattern is selected. The comparator circuit 6, the rectangular pattern M ₁ which sequentially sent, M _2, of the graphic data ...... M _6, the length of the first rectangular pattern M ₁ (x-direction length) m ₁
And the reference dimension δ. Since it is determined by the comparison that m ₁ > δ, the graphic data of the rectangular patterns M ₁ , M ₂ ,... M ₆ is supplied to the control device 8. Then, the control device stores the drawing data (writing position data, writing time data, and beam size data) of each pattern from the respective graphic data in the drawing data memory 9.

Further, comparison circuit 6, then, the rectangular pattern N ₁ which sequentially sent, N _2, ...... of the graphic data N _6, first in the x direction of the rectangular pattern N ₁ length n ₁ and the reference Compare the dimensions δ. Since it is determined by the comparison that n ₁ ≦ δ, the graphic data of each of the rectangular patterns N ₁ , N ₂ ,... N ₆ is supplied to the second rectangular pattern forming circuit 7. The second rectangular pattern creation circuit 7
Based on the input rectangular pattern data, data representing one rectangular pattern having dimensions of n _{1 in} the x direction and c in the y direction is created, and the graphic data of the rectangular pattern is stored in the control device 8.
To supply. The control device 8 stores the drawing data (writing position data, writing time data, and beam size data) of the pattern from the graphic data in the writing data memory 9.

At the time of pattern drawing, the control device 8 first calls the drawing data of the rectangular pattern L from the drawing data memory 9 sequentially, converts the drawing time data to the drawing time signal creation circuit 23, and converts the beam size data in the X direction into DA. The beam size data in the Y direction is supplied to the X direction shaping deflector 16 via the device 24 and the amplifier 25, and the X direction drawing position data is transmitted to the Y direction shaping deflector 17 via the DA converter 26 and the amplifier 27. The Y-direction drawing position data is sent to the X-direction positioning deflector 20 via the DA converter 28 and the amplifier 29 and to the Y-direction positioning deflector 21 via the DA converter 30 and the amplifier 31, respectively. Thus, the drawing time creation circuit 23 creates a drawing time signal (blanking signal) based on the inputted drawing time data, sends it to the blanking deflector 11, and performs the X-direction shaping. The beam deflector 16 and the Y-direction shaping deflector 17 shape the beam size of the electron beam from the electron gun 10 on the material 22 into a predetermined shape and size based on the beam size data sent. Then, drawing of a predetermined size is performed at a predetermined position on the material 22. Subsequently, drawing data of the rectangular patterns M ₁ , M ₂ ,..., M ₆ is sequentially called, and similarly, drawing of a predetermined size is performed at a predetermined position on the material 22. When the drawing of the rectangular pattern M ₆ is completed, followed by the drawing data of the rectangular pattern of the x dimension n _1, y dimension c is called, the same manner as described above, a predetermined size at a predetermined position on the material 22 Is drawn. As a result, a pattern as shown in FIG. 2 (e) is drawn.

Further, even if the figure data from the magnetic disk 1 represents a trapezoidal pattern, the figure dividing circuit 3 divides the figure if the bottom length of the trapezoidal pattern is smaller than the slit size of the mask plates 14 and 18. Instead, it is sent to the figure discrimination circuit 4 as it is. In this case, the figure discriminating circuit 4 discriminates the figure data as representing a trapezoid, and supplies the figure data to the first rectangular pattern creating circuit 5. The generating circuit generates graphic data representing rectangular patterns O ₁ , O ₂ ... O ₆ as shown in FIG. 2 (d), and supplies the respective graphic data to the comparing circuit 6. Subsequent operations are performed in the same manner as described above.

As described above, when the comparison circuit 6 determines that n ₁ ≦ δ, only the graphic data of the rectangular pattern N ₁ is supplied to the second rectangular pattern creating circuit 7, and the second rectangular pattern creating circuit 7 In the x direction n ₁ and the y direction, data representing a single rectangular pattern of dimension 6δ (= c), which is six times the length δ of the rectangular pattern N _{1 in} the y direction, is created, and the graphic data of the rectangular pattern is It may be supplied to the control device 8.

(Effects) According to the present invention, when the bottom of the triangular pattern or the longer bottom of the trapezoidal pattern is smaller than the reference dimension, the cross section of the charged particle beam is set to the two sides of the base and the height of the triangle or trapezoidal pattern. Since it is shaped into a rectangular shape and shot at a predetermined position on the material, if the bottom of the triangular pattern or the longer bottom of the trapezoidal pattern is smaller than the reference size, it can be drawn as one rectangular pattern, The overall drawing time can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a schematic view of an electron beam cross-section variable type drawing apparatus showing one embodiment of a charged particle beam drawing method of the present invention, and FIG. 2 shows a trapezoidal pattern. 1 ... magnetic disk, 2 ... control device, 3 ... figure dividing circuit, 4 ... figure discriminating circuit, 5 ... first rectangular pattern creating circuit, 6 ... comparing circuit, 7 ... second rectangular pattern creating Circuit 8, Control device 9, Drawing data memory 10,
... Electron gun, 11 ... Blanking electrode, 12 ... Blanking stop, 13,15 ... Focusing lens, 14 ... First mask plate, 1
6 ... X direction shaping deflector, 17 ... Y direction shaping deflector, 18 ... Second mask plate, 19 ... Projection lens, 20 ... X
Directional deflector, 21… Y-directional deflector, 22… material, 23… drawing time signal generation circuit, 24, 26,
28,30 …… DA converter, 25,27,29,31 …… Amplifier

Claims (1)

(57) [Claims] When the bottom of a triangular pattern or the longer side of a trapezoidal pattern is smaller than a reference size, the cross section of the charged particle beam is rectangular in shape with the bottom and the height of the triangle or trapezoidal pattern being two sides respectively. A charged particle beam drawing method in which a shot is formed at a predetermined position on a material by shaping into a predetermined shape.