JP2012151314A - Electronic beam lithography device and method for evaluating the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic beam lithography device and a method for evaluating the same, capable of accurately evaluating an irradiation position of an electronic beam regardless of a size of a deflection region.SOLUTION: A method for evaluating an electronic beam lithography device comprises: shooting a pattern 101 and shooting a pattern 102 adjacent to the pattern 101; then moving a shot position to a line pattern L3 adjacent to a line pattern L2 and shooting a pattern 103; then shooting a pattern 104 adjacent to the pattern 103; then moving a shot position to the line pattern L2 again and shooting a pattern 105; then shooting a pattern 106 adjacent to the pattern 105; then moving a shot position to the line pattern L3 again and shooting a pattern 107; then shooting a pattern 108 adjacent to the pattern 107; and repeating the same steps until shooting a pattern 180.

Description

  The present invention relates to an electron beam drawing apparatus and an evaluation method for an electron beam drawing apparatus.

  In recent years, along with the high integration and large capacity of large scale integrated circuits (LSIs), circuit line widths required for semiconductor elements are becoming increasingly narrow and fine. A semiconductor element uses an original pattern (a mask or a reticle, hereinafter referred to as a mask) on which a circuit pattern is formed, and the pattern is exposed and transferred onto a wafer by a reduction projection exposure apparatus called a stepper. It is manufactured by forming a circuit. An electron beam drawing apparatus is used for manufacturing a mask for transferring such a fine circuit pattern onto a wafer.

  The electron beam lithography system has an essentially excellent resolution because the electron beam used is a charged particle beam, and can secure a large depth of focus, so that it is possible to suppress dimensional fluctuations even on high steps. Have advantages. Patent Document 1 discloses a method for manufacturing a semiconductor integrated circuit device using an electron beam drawing apparatus.

  However, the exposure technique using an electron beam has a problem that the throughput is low as compared with the batch exposure using light. Therefore, conventionally, attempts have been made to improve the throughput by various methods.

  Specifically, by using a variable shaped beam instead of a circular cross-section electron beam, the number of exposures can be reduced, the stage movement can be changed to a continuous movement method instead of the step-and-repeat method, and the electron beam The deflection method is changed to a vector scanning method.

  By combining the above techniques, the throughput can be greatly improved. However, in the vector scanning method, since the deflection angle of the electron beam in the subfield differs depending on the position of the subfield in the frame, there may arise a problem that the shape, position and dimensional accuracy of the drawing pattern deteriorate. . For this, Patent Document 2 describes a method of detecting a sensitivity deviation of sub-deflection that occurs depending on the main deflection position of an electron beam before drawing, and correcting the detected value at the time of drawing.

  In order to improve the throughput, it is also necessary to deflect the electron beam at high speed and with high accuracy. However, when the deflector is driven by the deflection amplifier, a settling time (settling time) of the output voltage corresponding to the load is required. In other words, a predetermined settling time is required to set the target deflection position. Further, if the electron beam is irradiated onto the sample surface during the settling time, the drawing result is adversely affected. Therefore, during this time, the blanking mechanism must be operated so that the irradiation with the electron beam is not performed.

  Patent Document 3 describes a method of evaluating an irradiation position of an electron beam by a deflector by irradiating an electron beam onto a contact hole pattern arranged on two orthogonal straight lines. Specifically, in FIG. 4 of Patent Document 3, after irradiating the irradiation position (101) of the intersection of two straight lines A and B with an electron beam, the closest position to the irradiation position (101) on the straight line A is shown. Irradiation is performed by moving the electron beam to the irradiation position (102). Next, after moving and irradiating the electron beam to the next irradiation position (103) on the straight line B, the electron beam is moved to the irradiation position (104) closest to the irradiation position (103) on the straight line B. Irradiate. Next, after moving and irradiating the electron beam to the next irradiation position (105) on the straight line A, the same operation is repeated thereafter, and each irradiation position (106, 107, 108 and 109) on each straight line is determined. Irradiation with an electron beam in order. The optimum settling time can be obtained by measuring the amount of deviation between the desired irradiation position and the actual irradiation position. For convenience of explanation, the reference numerals used in FIG. 4 of Patent Document 3 are shown in parentheses.

JP-A-11-312634 JP-A-10-284392 Japanese Patent Laid-Open No. 2008-71986

  Recently, the main deflection area and the sub-deflection area have been reduced with the increase in accuracy of the electron beam drawing apparatus. For this reason, the evaluation method described in Patent Document 3 has the following problems.

  In Patent Document 3, as described above, an electron beam is irradiated onto contact hole patterns arranged on two orthogonal straight lines, and the irradiation position of the electron beam by the deflector is evaluated. Here, when the size of the contact hole pattern is the same and the sub-deflection area is small, the number of evaluation points that can be accommodated in the sub-deflection area is reduced. Although the shot size has been miniaturized due to the improvement in throughput, even if the shot size is reduced, the reduction in the evaluation score cannot be improved. For this reason, there has been a problem that it is difficult to accurately evaluate the irradiation position of the electron beam.

  On the other hand, it is also conceivable to reduce the number of evaluation points that can be accommodated in the sub deflection region by reducing the size of the contact hole pattern. However, the contact hole pattern is not a perfect rectangle but rounded at the four corners. For this reason, it is preferable to measure by avoiding the four corners. However, when the pattern size is reduced, there are problems that four corners enter the measurement area and the measurement error increases.

  The present invention has been made in view of these problems. That is, an object of the present invention is to provide an electron beam drawing apparatus and an electron beam drawing apparatus evaluation method capable of accurately evaluating the irradiation position of the electron beam regardless of the size of the deflection region.

  Other objects and advantages of the present invention will become apparent from the following description.

A first aspect of the present invention is a charged particle beam drawing apparatus that draws a predetermined pattern on a sample by controlling the position of the charged particle beam by a deflector disposed on the optical path of the charged particle beam.
At least two rectangular patterns adjacent in one direction are arranged by a charged particle beam with respect to a plurality of line patterns arranged continuously in a direction perpendicular to the one direction to a length substantially equal to the maximum deflection width of the deflector. ,
Shot the second rectangular pattern constituting the first line pattern and adjacent to the first rectangular pattern after the first rectangular pattern constituting the first line pattern is shot;
After the first rectangular pattern is shot, the step of shooting the third rectangular pattern constituting the second line pattern is repeated.

In the first aspect of the present invention, there may be three or more line patterns, and the first line pattern and the second line pattern may be adjacent to each other.
Alternatively, the dimension from the first line pattern to the second line pattern can be a dimension substantially equal to the maximum deflection width of the deflector.

A second aspect of the present invention is a charged particle beam drawing apparatus for drawing a predetermined pattern on a sample by controlling the position of the charged particle beam by a deflector disposed on the optical path of the charged particle beam.
With respect to a plurality of line patterns in which a rectangular pattern adjacent in one direction is continuously arranged in a direction orthogonal to the one direction to a length substantially equal to the maximum deflection width of the deflector,
Shot the second rectangular pattern constituting the second line pattern after the first rectangular pattern constituting the first line pattern is shot;
After the second rectangular pattern is shot, the first line pattern is formed and the step of shooting the third rectangular pattern adjacent to the first rectangular pattern is repeated. is there.

In the second aspect of the present invention, there may be three or more line patterns, and the first line pattern and the second line pattern may be adjacent to each other.
Alternatively, the dimension from the first line pattern to the second line pattern can be a dimension substantially equal to the maximum deflection width of the deflector.

According to a third aspect of the present invention, there is provided a charged particle beam drawing apparatus for drawing a predetermined pattern on a sample by controlling a position of the charged particle beam by a deflector disposed on an optical path of the charged particle beam.
A charged particle beam is applied to three or more line patterns in which at least two rectangular patterns adjacent in one direction are continuously arranged in a direction orthogonal to the one direction to a length substantially equal to the maximum deflection width of the deflector. By
Repeating the step of shot the second rectangular pattern constituting the second line pattern not adjacent to the first line pattern after the first rectangular pattern constituting the first line pattern is shot;
And a step of repeating a step of shot the fourth rectangular pattern constituting the third line pattern adjacent to the first line pattern after the third rectangular pattern constituting the first line pattern is shot. It is characterized by having been comprised.

In the third aspect of the present invention, after the first rectangular pattern constituting the first line pattern is shot, the second rectangular pattern constituting the second line pattern not adjacent to the first line pattern is shot. After the step of repeating is performed, after the third rectangular pattern constituting the first line pattern is shot, the fourth rectangular pattern constituting the third line pattern adjacent to the first line pattern is taken. A step of repeating the step of shot can be performed.
Alternatively, after the third rectangular pattern constituting the first line pattern is shot, the step of repeating the step of shot the fourth rectangular pattern constituting the third line pattern adjacent to the first line pattern is performed. After the first rectangular pattern constituting the first line pattern is shot, the step of repeating the step of shot the second rectangular pattern constituting the second line pattern not adjacent to the first line pattern is performed. It can also be done.

According to a fourth aspect of the present invention, there is provided an evaluation method for a charged particle beam drawing apparatus that draws a predetermined pattern on a sample by controlling a position of the charged particle beam by a deflector disposed on an optical path of the charged particle beam.
At least two rectangular patterns adjacent in one direction are arranged by a charged particle beam with respect to a plurality of line patterns arranged continuously in a direction perpendicular to the one direction to a length substantially equal to the maximum deflection width of the deflector. ,
Shot the second rectangular pattern constituting the first line pattern and adjacent to the first rectangular pattern after the first rectangular pattern constituting the first line pattern is shot;
And a step of shot a third rectangular pattern constituting the second line pattern after the first rectangular pattern is shot.

In the fourth aspect of the present invention, there may be three or more line patterns, and the first line pattern and the second line pattern may be adjacent to each other.
Alternatively, the dimension from the first line pattern to the second line pattern can be a dimension substantially equal to the maximum deflection width of the deflector.

According to a fifth aspect of the present invention, there is provided a charged particle beam drawing apparatus evaluation method for drawing a predetermined pattern on a sample by controlling a position of the charged particle beam by a deflector disposed on an optical path of the charged particle beam.
With respect to a plurality of line patterns in which a rectangular pattern adjacent in one direction is continuously arranged in a direction orthogonal to the one direction to a length substantially equal to the maximum deflection width of the deflector,
Shot the second rectangular pattern constituting the second line pattern after the first rectangular pattern constituting the first line pattern is shot;
And shot a third rectangular pattern that forms the first line pattern and is adjacent to the first rectangular pattern after the second rectangular pattern is shot.

In the fifth aspect of the present invention, there may be three or more line patterns, and the first line pattern and the second line pattern may be adjacent to each other.
Alternatively, the dimension from the first line pattern to the second line pattern can be a dimension substantially equal to the maximum deflection width of the deflector.

According to a sixth aspect of the present invention, there is provided an evaluation method for a charged particle beam drawing apparatus that draws a predetermined pattern on a sample by controlling a position of the charged particle beam by a deflector disposed on an optical path of the charged particle beam.
A charged particle beam is applied to three or more line patterns in which at least two rectangular patterns adjacent in one direction are continuously arranged in a direction orthogonal to the one direction to a length substantially equal to the maximum deflection width of the deflector. By
Repeating the step of shot the second rectangular pattern constituting the second line pattern not adjacent to the first line pattern after the first rectangular pattern constituting the first line pattern is shot;
Repeating the step of shot the fourth rectangular pattern constituting the third line pattern adjacent to the first line pattern after the third rectangular pattern constituting the first line pattern is shot. It is characterized by.
After the first rectangular pattern constituting the first line pattern is shot, the step of repeating the step of shot the second rectangular pattern constituting the second line pattern that is not adjacent to the first line pattern is performed. Performing a step of repeating the step of shot the fourth rectangular pattern constituting the third line pattern adjacent to the first line pattern after the third rectangular pattern constituting the first line pattern is shot. Can do.
Alternatively, after the third rectangular pattern constituting the first line pattern is shot, the step of repeating the step of shot the fourth rectangular pattern constituting the third line pattern adjacent to the first line pattern is performed. After the first rectangular pattern constituting the first line pattern is shot, the step of repeating the step of shot the second rectangular pattern constituting the second line pattern not adjacent to the first line pattern is performed. It can be carried out.

In the sixth aspect of the present invention, after the first rectangular pattern constituting the first line pattern is shot, the second rectangular pattern constituting the second line pattern not adjacent to the first line pattern is shot. After the step of repeating is performed, after the third rectangular pattern constituting the first line pattern is shot, the fourth rectangular pattern constituting the third line pattern adjacent to the first line pattern is taken. A step of repeating the step of shot can be performed.
Alternatively, after the third rectangular pattern constituting the first line pattern is shot, the step of repeating the step of shot the fourth rectangular pattern constituting the third line pattern adjacent to the first line pattern is performed. After the first rectangular pattern constituting the first line pattern is shot, the step of repeating the step of shot the second rectangular pattern constituting the second line pattern not adjacent to the first line pattern is performed. It can also be done.

  According to the present invention, there are provided an electron beam lithography apparatus and an electron beam lithography apparatus evaluation method capable of accurately evaluating the irradiation position of the electron beam regardless of the size of the deflection region.

3 is an example of an evaluation pattern in the first embodiment. 10 is an example of an evaluation pattern in the second embodiment. 10 is an example of an evaluation pattern in the third embodiment. FIG. 6 is a diagram illustrating a configuration of an electron beam drawing apparatus according to a fourth embodiment. FIG. 10 is an explanatory diagram of an electron beam drawing method in a fourth embodiment.

Embodiment 1 FIG.
In the present embodiment, an evaluation method of an electron beam drawing apparatus will be described.

  FIG. 1 shows an evaluation pattern in the present embodiment. The evaluation pattern is provided in the sub deflection region F. The sub deflection region F is, for example, a rectangle having a side of 50 μm to 100 μm, and the size is determined according to the deflection width of the sub deflector.

  As shown in FIG. 1, the evaluation pattern is composed of a plurality of line patterns (L1, L2, L3, L4, L5). Each line pattern has a configuration in which two contact hole patterns adjacent in the X direction are continuously arranged in the Y direction up to the full deflection width of the sub deflector. In the present embodiment, a configuration may be adopted in which two contact hole patterns adjacent in the Y direction are continuously arranged in the X direction up to the full deflection width of the sub deflector.

  Numerical values such as 1, 2, 3,... Shown in FIG. 1 represent the electron beam shot order by the sub-deflection when determining the sub-deflection settling time. In this example, first, the pattern 101 constituting the line pattern L2 is shot. The size of one shot is preferably reduced according to the size of the sub-deflection area. For example, the size of one shot can be a rectangle having a side of 50 nm (the same applies hereinafter). Next, the pattern 102 adjacent to the pattern 101 is shot. Next, the shot position is moved to the line pattern L3 adjacent to the line pattern L2. Specifically, the pattern 103 is shot, and then the pattern 104 adjacent to the pattern 103 is shot. Next, the shot position is moved again to the line pattern L2. Then, the pattern 105 is shot, and then the pattern 106 adjacent to the pattern 105 is shot. Then, the pattern 107 is shot again by moving to the line pattern L3. Next, the pattern 108 adjacent to the pattern 107 is shot. The above steps are repeated until a pattern 180 in FIG. 1 is shot. In FIG. 1, notation regarding the shot order and pattern from the ninth shot to the 79th shot is omitted.

  The electron beam irradiation is performed after setting to a desired deflection position for a predetermined settling time. However, if the settling time is insufficient, the electron beam is irradiated to a position shifted from the target deflection position. In this case, since the next electron beam irradiation is deflected with reference to the previous irradiation position, the deviation amount of the irradiation position gradually increases. Then, the settling time and the amount of deviation of the irradiation position cannot be accurately known, and it becomes difficult to optimize the settling time.

  In the example of FIG. 1, in the step of shooting the line pattern L2 and the line pattern L3, a shot having a small electron beam moving distance and a shot having a large electron beam are alternately switched. That is, the moving distance from the pattern 101 to the pattern 102 is small, but the moving distance from the pattern 102 to the pattern 103 is large. Further, the moving distance from the pattern 103 to the pattern 104 is small, but the moving distance from the pattern 104 to the pattern 105 is large.

  The moving distance and the deflection amount are correlated. In a shot with a small moving distance, the deflection amount is small and there is almost no deviation of the irradiation position. Therefore, there is almost no influence on the subsequent shot with a large moving distance. On the other hand, a shot with a large moving distance has a large deflection amount and a large amount of irradiation position deviation. However, if the movement distance of the next shot is small, the deviation of the irradiation position is reset, and the influence on the next shot with a large movement distance is almost eliminated.

  In the example of FIG. 1, since the moving distance from the pattern 101 to the pattern 102 is small, there is almost no deviation of the irradiation position in the pattern 102. Therefore, the deviation amount of the irradiation position in the next shot, that is, the pattern 103 can be accurately measured.

  On the other hand, the movement distance from the pattern 102 to the pattern 103 is larger than the previous movement distance, that is, the movement distance from the pattern 101 to the pattern 102. Therefore, the irradiation position shift amount in the pattern 103 also increases. However, since the next moving distance, that is, the moving distance from the pattern 103 to the pattern 104 is small, the deviation amount of the irradiation position generated in the pattern 103 is reset in the next shot. Therefore, the deviation amount of the irradiation position in the next shot, that is, the pattern 105 can be accurately measured.

  Since the moving distance from the pattern 104 to the pattern 105 is larger than the moving distance from the pattern 103 to the pattern 104, the deviation amount of the irradiation position in the pattern 105 is larger than the deviation amount of the irradiation position in the pattern 104. However, since the next shot, that is, the shot to the pattern 106 adjacent to the pattern 105, needs only a short moving distance, the amount of positional deviation generated in the pattern 105 is reset. Therefore, the amount of deviation of the irradiation position in the next shot, that is, the pattern 107 can be accurately obtained.

  As described above, by repeating the shot with the long moving distance and the shot with the small moving distance, the positional deviation amount generated in the shot with the large moving distance is reset each time. Accordingly, it is possible to accurately obtain the amount of deviation of the irradiation position of the electron beam.

  By the way, the moving distance of the electron beam is not single. Then, next, consider a shot having a longer moving distance than the above-described shot having a longer moving distance. For convenience, the former is referred to as “short distance movement” and the latter is referred to as “long distance movement”. In the present embodiment, “short distance” refers to the dimension between adjacent line patterns, and “long distance” refers to the maximum dimension in the sub deflection region. The dimension between them is called “medium distance”.

  In FIG. 1, a shot between the line pattern L1 and the line pattern L5 is considered.

  First, the pattern 201 constituting the line pattern L1 is shot. Next, a pattern 202 adjacent to the pattern 201 is shot. Next, the shot position is moved to the line pattern L5. Specifically, the pattern 203 is shot, and then the pattern 204 adjacent to the pattern 203 is shot. Next, the shot position is moved again to the line pattern L1. Then, the pattern 205 is shot, and then the pattern 206 adjacent to the pattern 205 is shot. Thereafter, the pattern moves to the line pattern L5 again, and the pattern 207 is shot. Next, a pattern 208 adjacent to the pattern 207 is shot. The above steps are repeated until a pattern 280 in FIG. 1 is shot. In FIG. 1, notation regarding the 89th and subsequent shot orders and the 89th to 152nd patterns are omitted.

  Also in the step of shooting the line pattern L1 and the line pattern L5, a shot with a small electron beam moving distance and a shot with a large distance are alternately switched. That is, the moving distance from the pattern 201 to the pattern 202 is small, but the moving distance from the pattern 202 to the pattern 203 is large. Further, the moving distance from the pattern 203 to the pattern 204 is small, but the moving distance from the pattern 204 to the pattern 205 is large.

  Specifically, since the moving distance from the pattern 201 to the pattern 202 is small, there is almost no deviation of the irradiation position in the pattern 202. Therefore, the amount of deviation of the irradiation position in the next shot, that is, the pattern 203 can be accurately measured.

  On the other hand, the movement distance from the pattern 202 to the pattern 203 is larger than the previous movement distance, that is, the movement distance from the pattern 201 to the pattern 202. Therefore, the irradiation position shift amount in the pattern 203 also increases. However, since the next moving distance, that is, the moving distance from the pattern 203 to the pattern 204 is small, the deviation amount of the irradiation position generated in the pattern 203 is reset. Therefore, the shift amount of the irradiation position in the next shot, that is, the pattern 205 can be accurately measured.

  Since the moving distance from the pattern 204 to the pattern 205 is larger than the moving distance from the pattern 203 to the pattern 204, the irradiation position shift amount in the pattern 205 is larger than the irradiation position shift amount in the pattern 204. However, since the next shot, that is, the shot to the pattern 206 adjacent to the pattern 205, needs only a short moving distance, the positional deviation amount generated in the pattern 205 is reset by the next shot. Therefore, the deviation amount of the irradiation position in the next shot, that is, the pattern 207 can be accurately obtained.

  As described above, even in the shot between the line pattern L1 and the line pattern L5, the shot with the large moving distance and the shot with the small moving distance are repeated, so that the positional deviation amount generated in the shot with the large moving distance is reduced. Reset each time. Accordingly, it is possible to accurately obtain the amount of deviation of the irradiation position of the electron beam.

  The optimum sub-deflection settling time for short distance movement is obtained as follows.

  In the present embodiment, from the result obtained by drawing the line pattern L2 and the line pattern L3, the shift amount of the electron beam irradiation position in the short distance movement can be measured, and the optimum settling time can be obtained.

  Specifically, the sub-deflection settling time is set to an arbitrary value, and the line patterns L2 and L3 are drawn as described above while the electron beam is deflected by the sub-deflector. Next, the position or dimension of each drawn pattern is measured with a measuring instrument. For example, in FIG. 1, the dimension from one end of the pattern 102 to the corresponding one end of the pattern 103 is measured with a dimension measuring instrument. Alternatively, the coordinates of the ends (excluding the four corners) or the center of each pattern are measured with a coordinate measuring instrument. And after calculating | requiring the deviation | shift amount from the design value of the obtained dimension or coordinate, the average position deviation | shift amount is calculated | required from these values.

  In the same manner as described above, an average positional deviation amount when the sub-deflection settling time is changed is obtained. Next, the average displacement amount is plotted against the sub-deflection settling time, and the optimum settling time during short-distance movement is determined from the obtained relationship. For example, the settling time that minimizes the amount of displacement can be set to the optimum value. From the viewpoint of throughput, it is preferable to set the settling time at which the slope of the curve representing the relationship between the settling time and the average misregistration amount becomes zero as an optimum value.

  The optimum sub-deflection settling time for long distance movement can be obtained in the same manner. That is, the line patterns L1 and L5 are drawn, and the position or dimension of each obtained pattern is measured by a measuring instrument. For example, in FIG. 1, the dimension from one end of the pattern 202 to the corresponding one end of the pattern 203 is measured with a dimension measuring instrument. Alternatively, the coordinates of one end (or center) of the pattern 202 and the coordinates of one end (or center) corresponding to the pattern 203 are measured by a coordinate measuring instrument. And after calculating | requiring the positional offset amount from the design position in each measured value, the average positional offset amount is calculated | required from these values.

  In the same manner as described above, an average positional deviation amount when the sub-deflection settling time is changed is obtained. Next, the average displacement amount is plotted against the sub-deflection settling time, and the optimum settling time during long distance movement is determined from the obtained relationship. For example, the settling time that minimizes the amount of displacement can be set to the optimum value. From the viewpoint of throughput, it is preferable to set the settling time at which the slope of the curve representing the relationship between the settling time and the average misregistration amount becomes zero as an optimum value.

  Further, the relationship between the moving distance of the electron beam due to the sub-deflection and the positional deviation amount is plotted with the sub-deflection settling time being constant. That is, as described above, the positional deviation amount during short-distance movement and the positional deviation amount during long-distance movement are known from the measurement. By interpolating these values, the position deviation during medium-distance movement is obtained. The amount of deviation can also be obtained. Note that, for example, in the evaluation pattern of FIG. 1, L2 and L4 may be drawn to determine the amount of displacement when moving at a medium distance, and this may be added to the plot.

  According to the configuration of the present embodiment, the evaluation pattern is composed of a plurality of line patterns, and these line patterns are arranged in parallel in the Y direction (or X direction), and the size of the contact hole pattern constituting each line pattern. Can be arbitrarily changed according to the size of the sub deflection region. Therefore, the number of contact holes that can be accommodated in the sub deflection region, that is, the number of evaluation points can be increased as compared with the evaluation pattern of Patent Document 3 in which contact holes are arranged on two orthogonal straight lines. In other words, even if the sub-deflection area is smaller than the conventional one, the decrease in the number of evaluation points can be suppressed, so that it is possible to accurately evaluate the irradiation position of the electron beam.

  In the present embodiment, a plurality of two contact hole patterns adjacent in the X direction (or Y direction) are continuously arranged in the Y direction to form a line pattern. According to this configuration, since a shot with a large moving distance and a shot with a small moving distance are repeated, it is possible to reset the amount of misalignment that occurs in a shot with a large moving distance each time. Accordingly, it is possible to accurately obtain the amount of deviation of the irradiation position of the electron beam.

Embodiment 2. FIG.
In this embodiment, another evaluation method of the electron beam drawing apparatus will be described.

  FIG. 2 shows an evaluation pattern in the present embodiment. The evaluation pattern is provided in the sub deflection region F. The sub deflection region F is, for example, a rectangle having a side of 50 μm to 100 μm, and the size is determined according to the deflection width of the sub deflector.

  As shown in FIG. 2, the evaluation pattern is composed of a plurality of line patterns (L11, L12, L13, L14, L15, L16). Each line pattern has a configuration in which a single contact hole pattern is continuously arranged in the Y direction up to the full deflection width of the sub deflector. In the present embodiment, a single contact hole pattern may be continuously arranged in the X direction to the full deflection width of the sub deflector.

  Numerical values such as 1, 2, 3,... Shown in FIG. 2 represent the electron beam shot order by sub-deflection when determining the sub-deflection settling time. In this example, first, a pattern 301 constituting the line pattern L13 is shot. The size of one shot is preferably reduced according to the size of the sub-deflection area. For example, the size of one shot can be a rectangle having a side of 50 nm (the same applies hereinafter). Next, the shot position is moved to the line pattern L14 adjacent to the line pattern L13. Specifically, the pattern 302 is shot, and then the shot position is moved again to the line pattern L13. Then, after the pattern 303 is shot, the pattern 304 is shot again by moving to the line pattern L14. The above steps are repeated until a pattern 340 in FIG. 2 is shot. In FIG. 2, the shot order from the 11th shot to the 38th shot and notation regarding the third and subsequent patterns are omitted.

  The evaluation pattern of FIG. 2 is suitable for checking whether or not the settling time obtained by the evaluation pattern of FIG. 1 is appropriate. In other words, the evaluation pattern in FIG. 2 is a pattern in which the distances between the shots are substantially equal and close to the pattern actually drawn. In this evaluation pattern, unlike the evaluation pattern described with reference to FIG. 1, the irradiation position deviation caused by a shot with a large moving distance cannot be reset by the next shot with a small moving distance. That is, the settling time is insufficient, and when the electron beam is irradiated to a position shifted from the target deflection position, the position shift amount is not reset by the next shot and gradually increases. Therefore, by using the settling time estimated in FIG. 1 and drawing with the evaluation pattern in FIG. 2, it is possible to easily determine whether or not this settling time is appropriate.

  The shot movement between the line patterns L13 and L14 described above is referred to as “short distance movement” in the present embodiment. Next, the “long distance movement” shot will be described. In the present embodiment, “short distance” refers to the dimension between adjacent line patterns, and “long distance” refers to the maximum dimension within the sub deflection region. The dimension between them is called “medium distance”.

  The settling time at the time of short-distance movement obtained from the evaluation pattern of FIG. 1 can be evaluated by drawing line patterns L13 and L14. On the other hand, the settling time at the time of long distance movement obtained from the evaluation pattern of FIG. 1 can be evaluated by drawing the line patterns L11 and L16.

  In FIG. 2, a shot between the line pattern L11 and the line pattern L16 is considered.

  First, a pattern 401 constituting the line pattern L11 is shot. Next, the shot position is moved to the line pattern L16. Specifically, the pattern 402 is shot, and then the shot position is moved again to the line pattern L11. Then, after the pattern 403 is shot, the pattern 404 is shot again by moving to the line pattern L16. The above process is repeated until a pattern 480 in FIG. 2 is shot. In FIG. 2, the notation regarding the shot order from the 46th shot to the 79th shot and the patterns from the 403th to the 479th shot are omitted.

  The above-described line patterns L11 and L16 are drawn using the settling time during long distance movement obtained in FIG. If the settling time is insufficient and the electron beam is irradiated to a position deviated from the target deflection position, the amount of this position deviation is not reset by the next shot and gradually increases. Therefore, it can be easily determined whether or not the settling time estimated in FIG. 1 is appropriate.

  The deviation amount of the irradiation position of the electron beam when the evaluation pattern of FIG. 2 is used is obtained as follows.

  For example, the line patterns L12 and L13 are drawn as described above. Next, the coordinate of the center of each drawn pattern is measured with a coordinate measuring device. And after calculating | requiring the positional offset amount from the design position of the obtained coordinate, the average positional offset amount is calculated | required from these values.

  Further, the relationship between the moving distance of the electron beam due to the sub-deflection and the positional deviation amount is plotted with the sub-deflection settling time being constant. That is, according to the evaluation pattern of FIG. 2, the amount of misalignment at the time of short distance movement and the amount of misalignment at the time of long distance movement can be found by measurement. By interpolating these values, The amount of misalignment can also be obtained. Note that, for example, L12 and L15 may be drawn with the evaluation pattern of FIG. 2 to obtain the amount of positional deviation during the middle distance movement, and this may be added to the plot.

  As a result of drawing the evaluation pattern of FIG. 2, when it is determined that the settling time is not appropriate, the evaluation pattern of FIG. 1 is drawn to confirm reproducibility or to optimize the settling time again. .

  According to the configuration of the present embodiment, the evaluation pattern is composed of a plurality of line patterns, and these line patterns are arranged in parallel in the Y direction (or X direction), and the size of the contact hole pattern constituting each line pattern. Can be arbitrarily changed according to the size of the sub deflection region. Therefore, the number of contact holes that can be accommodated in the sub deflection region, that is, the number of evaluation points can be increased as compared with the evaluation pattern of Patent Document 3 in which contact holes are arranged on two orthogonal straight lines. In other words, even if the sub-deflection area is smaller than the conventional one, the decrease in the number of evaluation points can be suppressed, so that it is possible to accurately evaluate the irradiation position of the electron beam.

  In this embodiment, there is no contact hole adjacent in the X direction (or Y direction), and one contact hole is arranged in one direction to form a line pattern. In this evaluation pattern, the amount of irradiation position shift caused by a shot with a large moving distance cannot be reset by the next shot with a small moving distance. That is, the settling time is insufficient, and when the electron beam is irradiated to a position shifted from the target deflection position, the position shift amount is not reset by the next shot and gradually increases. Therefore, according to this evaluation pattern, it can be easily determined whether or not the settling time is appropriate.

Embodiment 3 FIG.
In the present embodiment, another evaluation method of the electron beam drawing apparatus will be described.

  FIG. 3 shows an evaluation pattern in the present embodiment, which can be the same as the evaluation pattern described in the second embodiment.

  The evaluation pattern is provided in the sub deflection region F. The sub deflection region F is, for example, a rectangle having a side of 50 μm to 100 μm, and the size is determined according to the deflection width of the sub deflector.

  As shown in FIG. 3, the evaluation pattern is composed of a plurality of line patterns (L21, L22, L23, L24, L25, L26). Each line pattern has a configuration in which a single contact hole pattern is continuously arranged in the Y direction up to the full deflection width of the sub deflector. In the present embodiment, a single contact hole pattern may be continuously arranged in the X direction to the full deflection width of the sub deflector.

  Numerical values such as 1, 2, 3,... Shown in FIG. 3 represent the electron beam shot order by sub-deflection when determining the sub-deflection settling time. In this example, first, a pattern 501 constituting the line pattern L21 is shot. The size of one shot is preferably reduced according to the size of the sub-deflection area. For example, the size of one shot can be a rectangle having a side of 50 nm (the same applies hereinafter). Next, the shot position is moved to the line pattern L26. Then, after the pattern 502 is shot, the pattern pattern 503 is shot again by moving to the line pattern L21. The above steps are repeated until a pattern 520 in FIG. 3 is shot.

  Next, a pattern 521 constituting the line pattern L21 is shot. Next, the shot position is moved to the line pattern L22 adjacent to the line pattern L21. Specifically, the pattern 522 is shot, and then the shot position is moved again to the line pattern L21. Then, after the pattern 523 is shot, the pattern pattern 524 is shot again by moving to the line pattern L22. The above process is repeated until a pattern 540 in FIG. 3 is shot.

  In FIG. 3, notations relating to patterns 504 to 519 and 525 to 539 are omitted (the same applies hereinafter).

  In the present embodiment, the above-described shot movement between the line patterns L21 and L26 is referred to as “long distance movement”. The movement of the shot between the line patterns L21 and L22 is referred to as “short distance movement”. Here, “short distance” refers to the dimension between adjacent line patterns, and “long distance” refers to the maximum dimension within the sub-deflection region. The dimension between them is called “medium distance”.

  In the example of FIG. 3, the long-distance movement shot is first continued, and then the short-distance movement shot is changed from the middle. When the settling time is insufficient, if the long-distance movement shot is continued, the positional shift amount is gradually increased because it is not reset by the next shot. While the long-distance movement shot is continued, this misalignment amount is difficult to see, but when it is changed to the short-distance movement shot as in the example of FIG. 3, the misregistration amount becomes noticeable. Then, as the short-distance movement shot is continued, the positional deviation amount is eventually reset.

  As described above, when the shot of the long distance movement is continued and then changed to the shot of the short distance movement, the positional deviation amount can be clearly understood when the shot movement distance is switched. Therefore, according to this embodiment, it is possible to grasp the positional deviation visually, so it is possible to grasp the occurrence of a defect due to the positional deviation without performing measurement using a dimension measuring instrument or a coordinate measuring machine. .

  In the present embodiment, after a short-distance movement shot is continued first, it can be changed to a long-distance movement shot from the middle.

  For example, a pattern 523 constituting the line pattern L21 is shot. Next, the shot position is moved to the line pattern L22 adjacent to the line pattern L21. Specifically, the pattern 524 is shot, and then the shot position is moved again to the line pattern L21. Then, after the pattern 521 is shot, the pattern 522 is shot again by moving to the line pattern L22. The above steps are repeated until a pattern 512 in FIG. 3 is shot.

  Next, a pattern 509 constituting the line pattern L21 is shot. Next, the shot position is moved to the line pattern L26. Then, after the pattern 510 is shot, the pattern moves to the line pattern L21 and the pattern 507 is shot. The above steps are repeated until a pattern 502 in FIG. 3 is shot.

  When the shot of the short distance movement is continued first and then changed to the shot of the long distance movement from the middle, the positional deviation amount is as follows. That is, since there is almost no positional deviation in a short-distance movement shot, a clear positional deviation amount cannot be recognized. However, in the long distance movement shot, the positional deviation is larger than in the short distance movement shot. When the long-distance movement shot is continued, the positional deviation is accumulated without being reset, and the positional deviation amount gradually increases.

  Therefore, even if a shot with a short distance movement is continued and then switched to a shot with a long distance movement, if there is a positional shift, this can be easily recognized. In other words, even with this method, it is possible to grasp the occurrence of a defect due to misalignment without performing measurement using a dimension measuring instrument or a coordinate measuring machine.

Embodiment 4 FIG.
In this embodiment, an embodiment of an electron beam drawing apparatus according to the present invention will be described.

  FIG. 4 is a diagram mainly showing a configuration of a drawing control unit in the electron beam drawing apparatus according to the present embodiment.

  In FIG. 4, a stage 33 on which a mask substrate 32 as a sample is installed is provided in a sample chamber 31 of the electron beam drawing apparatus 30. The stage 33 is driven by the stage drive circuit 34 in the X direction (left-right direction on the paper surface) and the Y direction (vertical direction on the paper surface). The moving position of the stage 33 is measured by a position circuit 35 using a laser length meter or the like.

  An electron beam optical system 40 is installed above the sample chamber 31. The electron beam optical system 40 includes an electron gun 100, various lenses 37, 38, 39, 41, and 42, a blanking deflector 43, a shaping deflector 44, a beam scanning main deflector 45, and a beam scanning subsidiary. It comprises a deflector 46, two beam shaping apertures 47, 48, and the like.

  FIG. 5 is an explanatory diagram of an electron beam drawing method according to the present embodiment. This drawing method is realized by using the electron beam drawing apparatus 30 of the present embodiment.

  As shown in FIG. 5, the pattern 81 drawn on the mask substrate 32 is divided into strip-shaped frame regions 82. Drawing with the electron beam 20 emitted by the electron gun 100 of the electron beam drawing apparatus 30 is performed for each frame region 82 while the stage 33 continuously moves in one direction (for example, the X direction). The frame area 82 is further divided into sub-deflection areas 83, and the electron beam 20 draws only necessary portions in the sub-deflection areas 83. The frame area 82 is a strip-shaped drawing area determined by the deflection width of the main deflector 45, and the sub-deflection area 83 is a unit drawing area determined by the deflection width of the sub-deflector 46.

  With reference to FIGS. 4 and 5, the positioning of the electron beam 20 in the sub deflection region 83 is performed by the sub deflector 46. The position of the sub deflection region 83 is controlled by the main deflector 45. That is, the main deflector 45 positions the sub deflection region 83, and the sub deflector 46 determines the beam position in the sub deflection region 83. Further, the shape and size of the electron beam 20 are determined by the shaping deflector 44 and the beam shaping apertures 47 and 48. Then, the sub-deflection area 83 is drawn while continuously moving the stage 33 in one direction. When drawing of one sub-deflection area 83 is completed, the next sub-deflection area 83 is drawn. When drawing of all the sub-deflection areas 83 in the frame area 82 is completed, the stage 33 is moved stepwise in a direction orthogonal to the direction in which the stage 33 is continuously moved (for example, the Y direction). Thereafter, similar processing is repeated, and the frame area 82 is sequentially drawn.

  When performing drawing with an electron beam, first, data in a format in which pattern data (CAD data) of a semiconductor integrated circuit or the like designed using a CAD system can be input to the electron beam drawing apparatus 30 in FIG. Converted to (layout data). Next, after the layout data is converted and drawing data is created, the drawing data is divided into a size at which the electron beam 20 is actually shot, and then drawing is performed for each shot size.

  The drawing data converted from the layout data is recorded in the input unit 51 which is a storage medium, then read out by the control computer 50, and temporarily stored in the pattern memory 52 for each frame area 82 in FIG. . The pattern data for each frame area 82 stored in the pattern memory 52, that is, the frame information composed of the drawing position, the drawing graphic data, etc. is sent to the pattern data decoder 53 and the drawing data decoder 54 which are data analysis units. Next, the sub-deflection area deflection amount calculation unit 60, the blanking circuit 55, the beam shaper driver 56, the main deflector driver 57, and the sub-deflector driver 58 are sent via these.

  Information from the pattern data decoder 53 is sent to a blanking circuit 55 and a beam shaper driver 56. Specifically, the pattern data decoder 53 creates blanking data based on the drawing data and sends it to the blanking circuit 55. Further, desired beam dimension data is also created based on the drawing data, and is sent to the sub deflection region deflection amount calculation unit 60 and the beam shaper driver 56. Then, a predetermined deflection signal is applied from the beam shaper driver 56 to the shaping deflector 44 of the electron beam optical system 40 to control the shape and size of the electron beam 20.

  The sub deflection region deflection amount calculation unit 60 calculates the deflection amount (movement distance) of the electron beam for each shot in the sub deflection region 83 from the beam shape data created by the pattern data decoder 53. The calculated information is sent to the settling time determination unit 61, and the settling time corresponding to the movement distance by the sub deflection is determined.

  The settling time determined by the settling time determination unit 61 is sent to the deflection control unit 62, and then the blanking circuit 55, the beam shaper driver 56, the main shaper 56 It is appropriately sent to either the deflector driver 57 or the sub deflector driver 58.

  The drawing data decoder 54 creates positioning data for the sub deflection region 83 based on the drawing data, and sends this data to the main deflector driver 57 and the sub deflector driver 58. Then, a predetermined deflection signal is applied from the main deflector driver 57 to the main deflector 45 of the electron beam optical system 40, and the electron beam 20 is deflected and scanned to a predetermined main deflection position. Further, a predetermined sub deflection signal is applied from the sub deflector driver 58 to the sub deflector 46, and drawing is performed in the sub deflection region 83 of FIG. Specifically, this drawing is performed by repeatedly irradiating the electron beam 20 after a settling time has elapsed.

  The present embodiment is characterized in that an evaluation unit 63 that evaluates the electron beam drawing apparatus 30 is connected to a control computer 50. The evaluation unit 63 stores the evaluation pattern described in the first to third embodiments and the electron beam shot order. Information on the evaluation pattern and shot order selected according to the purpose is sent from the evaluation unit 63 to the deflection control unit 62.

  For example, when the amount of deviation of the electron beam irradiation position is measured and the sub-deflection settling time during short distance movement is obtained from the result, the evaluation pattern described in the first embodiment is used and the line patterns L2 and L3 are It is possible to select a shot order in which a shot with a short moving distance and a shot with a large moving distance are repeated. The selected information is sent to the deflection control unit 62, and the beam shaper driver 56, the main deflector driver 57, and the sub deflector driver 58 are controlled by the deflection control unit 62 according to this information. Further, the blanking circuit 55 is controlled by the deflection control unit 62 according to the settling time determined by the settling time determination unit 61.

  By measuring the deviation amount of the electron beam irradiation position in the pattern drawn under the above conditions, it is possible to evaluate whether or not the current settling time is appropriate. For example, the dimension from one end of a certain pattern to the corresponding one end of the next shot pattern is measured with a dimension measuring instrument. Alternatively, the coordinates of each end of these patterns (excluding the four corners) or the center are measured with a coordinate measuring instrument. And after calculating | requiring the deviation | shift amount from the design value of the obtained dimension or coordinate, the average position deviation | shift amount is calculated | required from these values. The suitability of the current settling time is evaluated depending on whether this value is larger than a threshold value.

  An appropriate sub-deflection settling time is obtained as follows.

  The settling time determined by the settling time determination unit 61 is changed, and a pattern is drawn in the same manner as described above. That is, information such as settling time, pattern shape, and shot order is sent from the deflection control unit 62 to the blanking circuit 55, the beam shaper driver 56, the main deflector driver 57, and the sub deflector driver 58 to perform drawing. Is called.

  The relationship between the sub-deflection settling time and the average positional deviation amount is obtained, and the optimum settling time is determined from this relationship. For example, the settling time that minimizes the amount of displacement can be set to the optimum value. From the viewpoint of throughput, it is preferable to set the settling time at which the slope of the curve representing the relationship between the settling time and the average misregistration amount becomes zero as an optimum value.

  Since the electron beam drawing apparatus of the present embodiment has an evaluation unit for evaluating the amount of deviation of the electron beam irradiation position, it is possible to evaluate the suitability of the settling time, and from the result, the proper settling You can ask for time. The evaluation pattern stored in the evaluation unit is composed of a plurality of line patterns. These line patterns are arranged in parallel in the Y direction (or X direction), and the size of the contact hole pattern constituting each line pattern. Can be arbitrarily changed according to the size of the sub deflection region. Therefore, compared to the conventional evaluation pattern in which contact holes are arranged on two orthogonal straight lines, the number of contact holes that can be accommodated in the sub deflection region, that is, the number of evaluation points can be increased. In other words, even if the sub-deflection area is smaller than the conventional one, the decrease in the number of evaluation points can be suppressed, so that it is possible to accurately evaluate the irradiation position of the electron beam.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

  For example, in each of the above embodiments, the settling time for the sub-deflection has been described, but the settling time for the main deflection can be considered similarly.

  Further, although the electron beam is used in the above embodiment, the present invention is applied to a charged particle gun conditioning method using another charged particle beam such as an ion beam and a charged particle beam drawing apparatus equipped with this charged particle gun. Is also applicable.

DESCRIPTION OF SYMBOLS 100 Electron gun 20 Electron beam 30 Electron beam drawing apparatus 31 Sample chamber 32 Mask substrate 33 Stage 34 Stage drive circuit 35 Position circuit 37, 38, 39, 41, 42 Various lenses 40 Electron beam optical system 43 Blanking deflector 44 Molding Deflector 45 Main deflector 46 Sub deflector 47, 48 Beam shaping aperture 50 Control computer 51 Input unit 52 Pattern memory 53 Pattern data decoder 54 Drawing data decoder 55 Blanking circuit 56 Beam shaper driver 57 Main deflector driver 58 Sub Deflector driver 60 Sub deflection region deflection amount calculation unit 61 Settling time determination unit 62 Deflection control unit 63 Evaluation unit 81 Pattern to be drawn 82 Frame region 83 Sub deflection region

Claims (6)

In a charged particle beam drawing apparatus for drawing a predetermined pattern on a sample by controlling the position of the charged particle beam by a deflector arranged on the optical path of the charged particle beam,
The charged particles with respect to a plurality of line patterns in which at least two rectangular patterns adjacent in one direction are continuously arranged in a direction orthogonal to the one direction to a length substantially equal to the maximum deflection width of the deflector. By beam
Shot the second rectangular pattern constituting the first line pattern and adjacent to the first rectangular pattern after the first rectangular pattern constituting the first line pattern is shot;
A charged particle beam drawing apparatus configured to repeat a step of shot a third rectangular pattern constituting a second line pattern after the first rectangular pattern is shot. In a charged particle beam drawing apparatus for drawing a predetermined pattern on a sample by controlling the position of the charged particle beam by a deflector arranged on the optical path of the charged particle beam,
With respect to a plurality of line patterns in which rectangular patterns adjacent in one direction are continuously arranged in a direction orthogonal to the one direction to a length substantially equal to the maximum deflection width of the deflector, the charged particle beam
Shot the second rectangular pattern constituting the second line pattern after the first rectangular pattern constituting the first line pattern is shot;
After the second rectangular pattern is shot, the step of configuring the first line pattern and shot the third rectangular pattern adjacent to the first rectangular pattern is repeated. Charged particle beam writing device. In a charged particle beam drawing apparatus for drawing a predetermined pattern on a sample by controlling the position of the charged particle beam by a deflector arranged on the optical path of the charged particle beam,
The charge is applied to three or more line patterns in which at least two rectangular patterns adjacent in one direction are continuously arranged in a direction orthogonal to the one direction to a length substantially equal to the maximum deflection width of the deflector. By particle beam,
Repeating the step of shot the second rectangular pattern constituting the second line pattern not adjacent to the first line pattern after the first rectangular pattern constituting the first line pattern is shot;
Repeating the step of shot the fourth rectangular pattern constituting the third line pattern adjacent to the first line pattern after the third rectangular pattern constituting the first line pattern is shot. A charged particle beam drawing apparatus characterized by being configured to perform. In the evaluation method of the charged particle beam drawing apparatus for drawing a predetermined pattern on a sample by controlling the position of the charged particle beam by a deflector arranged on the optical path of the charged particle beam,
The charged particles with respect to a plurality of line patterns in which at least two rectangular patterns adjacent in one direction are continuously arranged in a direction orthogonal to the one direction to a length substantially equal to the maximum deflection width of the deflector. By beam
Shot the second rectangular pattern constituting the first line pattern and adjacent to the first rectangular pattern after the first rectangular pattern constituting the first line pattern is shot;
And a step of shot a third rectangular pattern constituting the second line pattern after shot the first rectangular pattern. In the evaluation method of the charged particle beam drawing apparatus for drawing a predetermined pattern on a sample by controlling the position of the charged particle beam by a deflector arranged on the optical path of the charged particle beam,
With respect to a plurality of line patterns in which rectangular patterns adjacent in one direction are continuously arranged in a direction orthogonal to the one direction to a length substantially equal to the maximum deflection width of the deflector, the charged particle beam
Shot the second rectangular pattern constituting the second line pattern after the first rectangular pattern constituting the first line pattern is shot;
A charged particle beam comprising: shot the third rectangular pattern that forms the first line pattern and is adjacent to the first rectangular pattern after the second rectangular pattern is shot Evaluation method of drawing apparatus. In the evaluation method of the charged particle beam drawing apparatus for drawing a predetermined pattern on a sample by controlling the position of the charged particle beam by a deflector arranged on the optical path of the charged particle beam,
The charge is applied to three or more line patterns in which at least two rectangular patterns adjacent in one direction are continuously arranged in a direction orthogonal to the one direction to a length substantially equal to the maximum deflection width of the deflector. By particle beam,
Repeating the step of shot the second rectangular pattern constituting the second line pattern not adjacent to the first line pattern after the first rectangular pattern constituting the first line pattern is shot;
Repeating the step of shot the fourth rectangular pattern constituting the third line pattern adjacent to the first line pattern after the third rectangular pattern constituting the first line pattern is shot. A method for evaluating a charged particle beam writing apparatus, comprising:

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