JP2003077802A - Electron beam lithography device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electron beam lithography device and a method which is capable of drawing a pattern with high accuracy. SOLUTION: The system has a means 18 of moving a drawing region 10 defined on a sample so as to draw a pattern over regions, except a specified spot 16 within the region 10. On the specified spot 16, e.g. there is the possibility that a variable rectangular shot becomes or may become discontinuous. Except the specified spot 16, a pattern is drawn, to enable the pattern drawing without disconnection. This means is, e.g. one for moving a stage with the sample mounted thereon or one for moving the drawing area by electromagnetic deflection or may be one having a means of determining whether the pattern to be written locates at the specified spot by comparison of the pattern to be drawn with the coordinates of the drawing area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique of electron beam writing, and more particularly to correction of a writing position of a pattern in electron beam writing.

[0002]

2. Description of the Related Art In recent years, an electron beam drawing apparatus has been used for forming a resist pattern. The electron beam drawing apparatus places a sample on which a pattern is to be drawn on a stage, and forms a pattern in a predetermined drawing area while deflecting an electron beam from an electron gun by electromagnetic lens deflection. The drawing area is a position where the electron beam can be projected. Usually, a plurality of drawing areas are defined on the sample. A drawing area in which a pattern is to be drawn is selected from a plurality of drawing areas by movement of the stage and deflection by the electromagnetic lens and the deflection plate. The drawing area selected by moving the stage may be referred to as field A, and the drawing area selected by electromagnetic lens deflection may be referred to as field B.

Conventionally, it is said that the center of the field B is the position with the best drawing accuracy. Therefore, normally, the pattern data is processed so that the center of the pattern to be drawn is located at the center of the field B.

[0004]

However, the present inventor has found that the center of the field B cannot be said to be the position where the drawing accuracy is the best.

FIG. 1 shows one field B on the sample.
It is a figure which shows 10 typically. A stage (not shown) is moved to move the field B10 to a projectable position, and the electron beam is deflected by an electromagnetic lens or a deflection plate (not shown) to draw the variable rectangle 12. The voltage applied to the electromagnetic lens or the deflection plate is controlled to deflect the electron beam in the x-axis direction and the y-axis direction. The symbol o is field B
It means the origin of the coordinates for identifying the position within 10.
As described above, conventionally, the center of the field B10 was said to be the position with the best drawing accuracy. Therefore, the drawing pattern is located on this center.

However, it has been found that there are positions where the variable rectangular shots move discontinuously near the center of the field B. The cause of discontinuity can be presumed to be a problem in coordinate calculation method (including error accumulation), a problem in some kind of charging and electric signal of control system, but the cause cannot be clarified. It was However, since the failure is reproducible, it is considered to be a problem unique to the drawing system and method.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art and to provide an electron beam drawing apparatus and method capable of drawing a pattern with high accuracy.

[0008]

In order to solve the above problems, the present invention relates to an electron beam drawing apparatus for drawing a pattern on a sample with an electron beam, and a specific position within a drawing area defined on the sample. A means for moving the drawing area is provided so as to draw a pattern in an area other than. As a result, the pattern can be drawn with high accuracy.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the principle of the present invention will be described with reference to FIG.

FIG. 2A is a diagram showing a conventional pattern drawing. The protruding portion of the pattern 14 to be written in the field B10 extends over the drawing failure area 16 located near the center of the field B10. Therefore, there is a possibility that drawing of this protruding portion will be defective.

On the other hand, in the present invention, as shown in FIG. 2B, the field B10 is moved as shown by the arrow 18 so that the pattern 14 does not cover the drawing failure area 16. This movement is performed, for example, by processing the coordinates of the field B10 and setting the origin O of the field B10 to O.
It is done by moving to 1. In this movement, the direction in which the field B10 is moved and the distance are related. By calculating the direction and distance for moving the field B10 (in other words, calculating the offset amount), the pattern 14 can be accurately formed at a specific position in the field B10 that is the drawing area, that is, an area excluding the drawing failure area 16. Can be drawn. FIG. 3 shows the pattern 14 drawn by moving the field B10 of FIG. 2B with respect to the pattern 14 of FIG.

The defective drawing region 16 is different for each electron beam drawing apparatus due to a deflection system and a factor peculiar to the electron beam drawing apparatus. Therefore, the drawing defect area 16 peculiar to the electron beam drawing apparatus is
A test pattern is drawn on the sample to detect the. The test pattern may be any pattern. For example, it is formed by repeating lines and spaces. After drawing a pattern on the sample, a resist is applied to this and the entire surface is patterned. Then, the drawing defect area 16 is specified by a predetermined inspection method. The defective drawing area 16 is at the center of the field B10 or at a position slightly deviated from this, and varies depending on the electron beam drawing apparatus. Also,
The size of the drawing failure area 16 often differs from device to device. However, multiple fields B10 in the same device
Regarding each of the above, the drawing failure region 16 is located at almost the same position, and the sizes thereof can be said to be substantially the same. Further, if all the fields B are not moved in the same manner, pattern formation may be hindered. Therefore, it is preferable to move all the fields B in the same direction by the same distance. .

In this way, the defective drawing region 16 is specified, and the positional relationship with the exposure pattern to be drawn in the field B10 is inspected to determine whether or not the field B10 should be moved and to what extent. be able to.

In this case, as shown in FIG. 4, by moving the pattern 14 so that it does not cover the drawing failure area 16, the field B10L adjacent to the field B10 where the pattern 14 originally existed may be overlapped. Conceivable. In this case, field B
Disable movement of 10. A step may occur in the pattern 14 at the boundary between the fields B10 and 10L.
In the case of invalidation, the calculation is performed again and the pattern 14 is moved within a range that does not cover the adjacent field B10L so that the overlapping portion of the pattern 14 and the drawing failure area 16 is reduced as much as possible, or the pattern The relatively thick portion is made to overlap the drawing failure area 16. In addition, the field B1
The moving distance and the direction of 0 may be determined. In the worst case, the field B10 may not be moved.

Next, an embodiment of the present invention will be described.

FIG. 5 is a diagram showing an embodiment of an electron beam drawing apparatus and method according to the present invention. Electron beam drawing apparatus 100
Is a database 2 that stores CAD pattern data
0, a data processing unit 22 that processes CAD pattern data read from the database 20 to generate exposure pattern data, and an exposure unit 24 that draws a pattern on a sample according to the exposure pattern data.

The exposure section 24 has a signal conversion section 26, a stage control section 28, a deflection coil control section 30, and the following optical system. The optical system includes an electron gun 32 and an electromagnetic deflection coil 36.
And a stage 40.

CAD stored in the database 20
The pattern data is data of all the patterns to be drawn using CAD. Data processing unit 22
Converts CAD pattern data to generate exposure data to be supplied to the exposure unit 24. In the generation of this exposure data, the data processing unit 22 obtains the position information (position coordinates) of the drawing failure area 16 generated in step S12 of the electron beam drawing method described later and the position shift data generated in step S13. The exposure data generated from the CAD pattern data is corrected with reference. The position shift data is data relating to the exposure pattern overlapping the drawing failure area 16.

The signal converter 26 converts the exposure data, which is a digital signal, into an apparatus control signal. This device control signal is a first control signal for moving the stage 40 and a second control signal corresponding to the voltage value given to the electromagnetic deflection coil and the electromagnetic deflection plate 36. The stage control unit 28 converts the first control signal supplied from the signal conversion unit 26 to move the stage 40 (not shown).
Generate a voltage signal to be applied directly to. The deflection coil control unit 30 converts the second control signal supplied from the signal conversion unit 26 to generate a voltage signal to be applied to the electromagnetic deflection coil and the electromagnetic deflection plate 36. An electron beam 34 output from the electron gun 32 is deflected by an electromagnetic deflection coil and an electromagnetic deflection plate 36, and irradiates a sample or silicon or compound semiconductor (semi-insulating) semiconductor substrate 38 mounted on a stage 40. To be done.

The electron beam drawing method shown in FIG.
11 to S15 are included. In step S11, a test pattern is formed. The test pattern stored in the database 20 is read, converted into exposure data by the data processing unit 22, and then output to the exposure unit 24. Then, according to the exposure data of the test pattern, the semiconductor substrate 3
A test pattern is formed on the surface 8.

In step S12, the test pattern thus formed is inspected. The inspection is to check the discontinuous movement of the variable rectangular shots as described above. In addition to this characteristic, the drawing failure area 16 may be specified by paying attention to another parameter. Step S
The position information regarding the defective drawing region 16 identified in the inspection 12 is output to the data processing unit 22.

In step S13, it is checked whether or not the exposure pattern 14 exists in the drawing failure area 16, and if it exists, the coordinate data regarding this exposure pattern 14 is output to the data processing unit 22 as position shift data. The processing of step S13 may be performed by the data processing unit 22 or another computer connected to the electron beam exposure apparatus 100. The data processing unit 22 performs step S12.
The position information of the drawing failure area 16 acquired in step S
Using the position shift data acquired in 13, the moving direction and the moving distance of the field B10 required to eliminate the overlap between the exposure pattern 14 and the drawing failure area 16 are calculated. This calculation avoids the occurrence of the situation shown in FIG.

In step S14, it is checked whether the exposure pattern 14 after the field B10 is moved is present in the drawing failure area 16. The process of step S14 may be performed by the data processing unit 22 or another computer connected to the electron beam exposure apparatus 100. When it is determined by this check that the exposure pattern 14 after the field B10 is moved exists in the drawing failure area 16, the data processing unit 22 recalculates again. In this case, the adjacent field B10L
The pattern 14 is moved within a range that does not cover the pattern 14 so that the portion where the pattern 14 and the drawing failure area 16 overlap is as small as possible, or the relatively thick portion of the pattern overlaps the drawing failure area 16. Further, the moving distance and the direction of the field B10 may be determined by a method other than these methods. In the worst case, the field B10 may not be moved.

If the determination result in step S14 is OK, an exposure start instruction is given to the exposure section 24 in step S15.

In the above description, the field B10 is moved. In order to eliminate the overlap between the exposure pattern 14 and the drawing failure area 16, the field B1
In addition to 0, the field A50 shown in FIG. 6 (including a plurality of matrix-shaped fields B10) may be moved. Alternatively, only the field A50 may be moved to eliminate the overlap between the exposure pattern 14 and the drawing failure area 16.

FIG. 7 is a graph showing the relationship between the offset amount of the field B10 and the pattern discontinuity amount. This graph is obtained from the experiment. Offset amount,
That is, the drawing discontinuity of the field B10 or the field A50 is moved in the direction calculated by the distance calculated, thereby reducing or substantially eliminating the pattern discontinuity caused by the discontinuity of the variable rectangular shots. You can

Finally, some of the gist of the present invention will be listed below.

(Supplementary Note 1) In an electron beam drawing apparatus for drawing a pattern on a sample with an electron beam, the drawing area is formed so that the pattern is drawn in an area other than a specific position within the drawing area defined on the sample. An electron beam drawing apparatus having a moving means.

(Supplementary Note 2) The electron beam drawing apparatus according to Supplementary Note 1, wherein the means moves the stage on which the sample is placed.

(Supplementary Note 3) The electron beam drawing apparatus according to Supplementary Note 1, wherein the means moves the drawing area by means of an electromagnetic deflector and an electromagnetic deflector.

(Supplementary Note 4) The means has means for comparing the pattern to be drawn with the coordinates of the drawing area to determine whether or not the pattern to be drawn is at the specific position. 4. The electron beam drawing apparatus according to any one of appendices 1 to 3.

(Supplementary Note 5) The means has means for moving the drawing area to verify that the pattern drawn in the area other than the specific position does not extend over the adjacent drawing areas. 5. The electron beam drawing apparatus according to any one of appendices 1 to 4.

(Additional remark 6) The electron beam drawing apparatus according to any one of additional remarks 1 to 5, wherein the specific position is a position where drawing accuracy is lower than other positions.

(Supplementary Note 7) In the electron beam drawing method of drawing a pattern on a sample with an electron beam, the drawing area is defined so that the pattern is drawn in an area other than a specific position in the drawing area defined on the sample. An electron beam drawing method comprising a step of moving.

(Supplementary Note 8) In the electron beam drawing method according to Supplementary Note 7, the stage in which the sample is placed is moved in the step.

(Additional remark 9) The electron beam drawing method according to additional remark 7, wherein in the step, the drawing area is moved by an electromagnetic deflection and an electromagnetic deflecting plate.

(Supplementary Note 10) The step includes the step of determining whether or not the pattern to be drawn is at the specific position by comparing the pattern to be drawn with the coordinates of the drawing area. 10. The electron beam drawing method according to any one of appendices 7 to 9.

(Supplementary Note 11) The step includes a step of moving the drawing area to verify that a pattern drawn in an area other than the specific position does not extend over an adjacent drawing area. 11. The electron beam drawing method according to any one of appendices 7 to 10.

(Additional remark 12) The electron beam drawing apparatus according to any one of additional remarks 7 to 11, wherein the specific position is a position where drawing accuracy is poorer than other positions.

[0040]

As described above, according to the present invention,
An electron beam drawing apparatus and method capable of drawing a pattern with high accuracy can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing a conventional technique and its problems.

FIG. 2 is a diagram for explaining the principle of the present invention in comparison with the prior art.

FIG. 3 is a diagram showing a relationship between a pattern drawn by the present invention and a drawing failure area.

FIG. 4 is a diagram showing a relationship between a pattern and a drawing failure area which cannot be said to be preferable for drawing according to the present invention.

FIG. 5 is a diagram showing an embodiment of the present invention.

FIG. 6 is a diagram showing a relationship between a field A and a field B.

FIG. 7 is a graph showing a relationship between an offset amount and a pattern discontinuity amount showing the effect of the present invention.

[Explanation of symbols]

10 Field B 14 patterns 16 drawing discontinuity area 18 Move Field B

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Naoya Ichichi             4-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa             No. 1 within Fujitsu Limited (72) Inventor Gozo Makiyama             4-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa             No. 1 within Fujitsu Limited (72) Inventor Katsumi Ogiri             Yamanashi Prefecture Nakakoma-gun Showa-cho Large-sized paper Sashi Ahara 1000             Within Fujitsu Quantum Devices Limited F-term (reference) 2H097 CA16 LA10                 5C034 BB04 BB06 BB07                 5F056 CA02 CA28 CB11 EA06

Claims (5)

[Claims] 1. An electron beam drawing apparatus for drawing a pattern on a sample with an electron beam, wherein the drawing area is moved so as to draw a pattern in an area other than a specific position within the drawing area defined on the sample. An electron beam drawing apparatus having means. 2. The electron beam drawing apparatus according to claim 1, wherein the means moves a stage on which a sample is placed. 3. The electron beam drawing apparatus according to claim 1, wherein the means moves the drawing area by electromagnetic deflection. 4. The means includes means for comparing the pattern to be drawn with the coordinates of the drawing area to determine whether or not the pattern to be drawn is at the specific position. The electron beam drawing apparatus according to claim 1. 5. An electron beam drawing method for drawing a pattern on a sample with an electron beam, wherein the drawing area is moved so as to draw a pattern in an area other than a specific position within a drawing area defined on the sample. An electron beam drawing method having a step.