JP4818501B2 - Electron beam exposure system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electron beam exposure apparatus that performs multiple drawing of semiconductor circuit patterns and the like using an electron beam, and in particular, an electron beam exposure apparatus that realizes high-precision pattern position accuracy while minimizing a decrease in throughput (processing efficiency). It is about.
[0002]
[Prior art]
Conventionally, an electron beam drawing apparatus that realizes high-precision drawing by irradiating a predetermined position with an electron beam based on drawing position information on a drawing substrate is referred to, for example, in Japanese Patent Laid-Open No. 11-8171. Various proposals have been made.
[0003]
This type of electron beam drawing apparatus uses drawing position information such as a semiconductor circuit pattern on a drawing substrate irradiated with an electron beam, a drawing pattern position correction coefficient, etc. in order to achieve high accuracy of the drawing position. It has also been proposed to execute actual pattern drawing after correction.
[0004]
Also, in multiple drawing by electron beam exposure, the irradiation amount per drawing is reduced, and the same pattern is drawn over several times, thereby reducing the degradation of position accuracy due to fluctuations in the beam position. An apparatus that realizes high drawing position accuracy has also been proposed.
[0005]
Hereinafter, a specific operation of the multiple drawing process by the conventional electron beam exposure apparatus will be described with reference to FIG.
FIG. 8 is a flowchart showing multiple drawing processing by a conventional electron beam exposure apparatus, and shows a case where multiple drawing is executed a predetermined number of times (N times).
[0006]
In FIG. 8, first, the counter value M of the number of drawing is cleared to 0 (step S1), then the counter value M is incremented (step S2), and beam drift correction is executed (step S3).
[0007]
That is, before actual drawing, the reference mark position on the stage or the drawing substrate is measured by an electron beam exposure apparatus, and the relative displacement between the reference mark position and the electron beam position is detected. The drift of the drawing position is corrected using the amount as a beam drift amount.
[0008]
Note that the coordinate position of the reference mark is known in advance, and the amount of positional deviation of the reference mark position before electron beam exposure is compared by comparing the reference mark position measured immediately before multiple drawing with a known coordinate position. Can be requested.
[0009]
Next, M-th drawing (first time) of multiple drawing is started (step S4), and actual drawing is executed based on drawing position information given in advance (step S5).
[0010]
Here, for example, the beam drift correction (step S3) may be executed only a plurality of times between the start and end of the M-th drawing, or the beam position is corrected by predicting the amount of beam drift during drawing. May be executed.
[0011]
Next, after the M-th drawing is completed (step S6), it is determined whether or not the counter value M is smaller than the predetermined number N (step S7).
If it is determined in step S7 that M <N (that is, YES), since the number M of drawing has not reached the predetermined number N, the process returns to step S2 and the above process is repeated.
[0012]
That is, after the counter value M is incremented (step S2), the beam drift correction (step S3) is executed again, and the next multiple drawing process (steps S4 to S6) is executed.
[0013]
Similarly, if it is determined in step S7 that M = N (that is, NO), the counter value M has reached the predetermined number N (the drawing from one to N times is repeated and the multiple drawing is completed). Therefore, the N-fold multiple drawing process in FIG.
[0014]
[Problems to be solved by the invention]
As described above, the conventional electron beam exposure system performs beam drift correction using the initially detected misregistration amount as the beam drift amount. Therefore, if beam drift occurs during drawing, accurate drift is achieved. There has been a problem that a positional deviation amount occurs without correction.
[0015]
Further, if a large number of beam drift corrections are set in order to correct such a displacement amount, an extra beam drift correction time is generated, resulting in a problem that throughput is lowered.
[0016]
For example, as referred to in Japanese Patent Application Laid-Open No. 11-8171, when the beam drift during drawing is corrected using the predicted beam drift, the difference between the actual beam drift and the predicted beam drift becomes the positional deviation amount. As a result, there is a problem that the drawing position accuracy is lowered.
[0017]
The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain an electron beam exposure apparatus that realizes high-precision pattern drawing position accuracy while minimizing a decrease in throughput.
[0018]
[Means for Solving the Problems]
An electron beam exposure apparatus according to claim 1 of the present invention is an electron beam exposure apparatus that performs multiple drawing by irradiating an electron beam onto a drawing substrate a plurality of times. I-th drawing The actual drawing position on the generated drawing board Ri And target pattern position Ro Misalignment (Ri-Ro) Misregistration amount determination means for determining whether or not there is multiple drawing, and the amount of misalignment that occurred during multiple drawing (Ri-Ro) For later multiple drawing In the jth drawing (j> i) Correction operation means for correcting the drawing position during the remaining multiple drawing included in the multiple drawing so as to cancel The correction operation means determines the j-th drawing position Rj in the correction scan by the following equation, Rj = Ro− (Ri−Ro). Is.
[0019]
The electron beam exposure apparatus according to a second aspect of the present invention is the electron beam exposure apparatus according to the first aspect, wherein the correction operation means remains so as to cancel out misalignment amounts generated at a plurality of locations from the start to the end of the multiple drawing. The drawing position correction operation is performed a plurality of times during multiple drawing.
[0020]
The electron beam exposure apparatus according to a third aspect of the present invention is the electron beam exposure apparatus according to the first or second aspect, wherein the correction operation means cancels the average misregistration amount generated a plurality of times at the drawing position by multiple drawing. A drawing position correction operation is performed during the remaining multiple drawing.
[0021]
An electron beam exposure apparatus according to a fourth aspect of the present invention is the electron beam exposure apparatus according to the third aspect, wherein the correction operation means divides the remaining multiple drawing into a plurality of times so as to cancel out the misregistration amount generated at the drawing position. A correction operation is performed.
[0022]
An electron beam exposure apparatus according to a fifth aspect of the present invention is the electron beam exposure apparatus according to any one of the first to fourth aspects, wherein the correction operation means performs a correction operation using a correction coefficient for the drawing position.
[0023]
According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the correction operation means performs a correction operation using electron beam drift correction.
[0024]
An electron beam exposure apparatus according to a seventh aspect of the present invention is the electron beam exposure apparatus according to the sixth aspect, wherein the correction operation means performs drift correction using the predicted beam drift.
[0025]
An electron beam exposure apparatus according to an eighth aspect of the present invention is the electron beam exposure apparatus according to the sixth or seventh aspect, wherein the drawing substrate has a plurality of reference marks whose coordinate positions are known in advance, and the correction operation means is a reference operation Drift correction is performed using the coordinate position of the mark.
[0026]
An electron beam exposure apparatus according to a ninth aspect of the present invention is the electron beam exposure apparatus according to the eighth aspect, wherein the correction operation means performs a correction operation using a correction coefficient for the drawing position obtained from the coordinate position of the reference mark. is there.
[0027]
An electron beam exposure apparatus according to a tenth aspect of the present invention is the electron beam exposure apparatus according to any one of the first to ninth aspects, wherein the drawing substrate has a plurality of reference marks whose coordinate positions are known in advance, and a correction operation is performed. The means performs a correction operation using the coordinate positions of a plurality of reference marks.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
Hereinafter, the first embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram schematically showing Embodiment 1 of the present invention.
[0029]
In FIG. 1, 10 is a target pattern position calculating means for calculating a target pattern position Ro, 11 is a positional deviation amount determining means for calculating a positional deviation amount between the target pattern position Ro and the actual drawing pattern position, and 12 is a positional deviation amount. Is a correction operation means for performing a correction operation for canceling, and these means 10 to 12 are constituted by a microcomputer.
[0030]
Reference numeral 13 denotes electron beam irradiation means for irradiating the electron beam B, and irradiates the electron beam B controlled based on the target pattern position Ro and the correction operation means 12.
Reference numeral 14 denotes a drawing substrate on which multiple drawing of a required pattern is performed when the electron beam B is irradiated.
[0031]
The positional deviation amount determination means 11 is based on the coordinate position of a reference mark (not shown) on the drawing substrate 14 and the actual drawing position on the drawing substrate 14 generated from the start to the end of multiple drawing. And the presence or absence of a positional deviation amount (drift error) between the target pattern position Ro and the target pattern position Ro.
[0032]
The correction operation means 12 corrects and controls the drawing position by correcting the electron beam irradiation means 13 during the remaining multiple drawing included in the multiple drawing so as to cancel out the amount of displacement when a drift error occurs. I do.
[0033]
FIG. 2 is an explanatory view schematically showing an electron beam exposure position (drawing position) according to Embodiment 1 of the present invention.
In FIG. 2, Ro is a target pattern position to be drawn, Ri is an i-th pattern drawing position in N multiple drawing, and Rj is a j-th (N ≧ j> i) pattern drawing position.
[0034]
Here, the i and j-th pattern drawing positions Ri and Rj have deviation amounts (see arrows) with respect to the target pattern position Ro, and the pattern drawing positions other than the i and j-th pattern drawing positions are the target pattern position Ro. Is equal to
[0035]
The deviation amount of the pattern drawing position Rj is set so as to cancel out the deviation amount of the pattern drawing position Ri.
In addition, although each pattern drawing position in FIG. 2 should be originally shown in two dimensions, in order to avoid complexity, it is shown in only one dimension for convenience.
[0036]
Hereinafter, with reference to FIG. 1 and FIG. 2, a correction operation related to the i and j-th pattern drawing positions Ri and Rj at the time of multiple drawing according to the first embodiment of the present invention will be described.
[0037]
As is apparent from FIG. 2, the i-th pattern drawing position Ri has a positional deviation amount (= Ri−Ro) due to beam drift or the like with respect to the target pattern position Ro.
[0038]
Therefore, in the multiple drawing j (> i) drawing, the drawing is performed while performing the newly added correction operation so that the pattern drawing position Rj cancels the pattern position shift amount (= Ri-Ro) at the i-th drawing. I do.
That is, the pattern drawing position Rj is set so as to satisfy the following expression (1).
[0039]
Rj = Ro- (Ri-Ro) (1)
[0040]
Here, since the displacement amount at the i-th time (= Ri-Ro) is sufficiently smaller than the dimension of the drawing pattern, the drawing pattern after the completion of the multiple drawing overlaps each pattern drawing position at the time of the multiple drawing. Formed at the center of gravity.
[0041]
Therefore, the pattern drawing position Rij obtained by superimposing the i-th pattern drawing position Ri and the j-th pattern drawing position Rj is expressed as the following equation (2).
[0042]
Rij = (Ri + Rj) / 2 (2)
[0043]
Further, if the above formula (1) is substituted, the formula (2) is expressed as the following formula (3).
[0044]
Rij = (Ri + Ro− (Ri−Ro)) / 2 = Ro (3)
[0045]
That is, the pattern drawing position Rij obtained by superimposing the pattern drawing positions Ri and Rj is equal to the target pattern position Ro.
Further, since the pattern drawing positions other than the i-th and j-th times are equal to the target pattern position Ro, the pattern drawing position obtained by superimposing them all becomes equal to the target pattern position Ro.
[0046]
Next, the correction operation in the electron beam exposure process (multiple drawing process) according to the first embodiment of the present invention will be specifically described with reference to the flowchart of FIG.
[0047]
In FIG. 3, steps S2 to S7 are the same as those described above (see FIG. 8), and thus detailed description thereof is omitted here. Step S10 corresponds to step S1 described above.
[0048]
First, after clearing the counter value M and the correction operation flag F to 0 (step S10), following the increment processing of the counter value M (step S2), it is determined whether or not the correction operation flag F is set. Determination is made (step S11).
[0049]
If it is determined in step S11 that F = 1 (that is, YES), a positional deviation amount has occurred in the previous drawing. Therefore, after performing an additional correction operation (step S12), a beam drift correction process ( Proceed to step S3).
[0050]
On the other hand, if it is determined in step S11 that F = 0 (that is, NO), the positional deviation amount has not occurred in the previous drawing, so the process proceeds to step S3 without executing step S11.
[0051]
Thereafter, after the M-th drawing is completed (step S6), it is determined whether or not there is a displacement amount with respect to the target pattern position Ro (step S13), and if there is a displacement amount (that is, YES). If it is determined, the correction operation flag F is set to “1” (step S14), and then the process proceeds to step S7.
[0052]
On the other hand, if it is determined in step S13 that there is no misalignment (that is, NO), the correction operation flag F is cleared to 0 (step S15), and then the process proceeds to step S7.
[0053]
As a result, when a misregistration amount occurs, the correction operation flag F is set, so that an additional correction operation (step S12) is executed in the next drawing process.
[0054]
As described above, during the electron beam exposure for multiple drawing, the remaining multiple drawing is performed by the newly added correction operation so as to cancel the positional deviation amount of the drawing pattern generated from the start to the end of the multiple drawing. Thus, it is possible to obtain a highly accurate drawing pattern position accuracy in which the drawing position is accurately corrected and the displacement amount of the drawing pattern is eliminated.
[0055]
In addition, since the amount of misalignment occurring during multiple drawing can be canceled in subsequent multiple drawing, it is not necessary to correct the amount of misalignment during each drawing with high accuracy.
[0056]
Therefore, the number of times of beam drift correction can be reduced, and the extra time generated by the beam drift correction is reduced, so that a decrease in throughput due to the beam drift correction can be minimized.
[0057]
In this example, a correction operation that cancels the pattern misalignment amount for one time in the i-th multiple drawing is executed in the j-th multiple drawing. However, the amount of misalignment generated in the multiple times of multiple drawing is summed up. The correction operation may be performed so as to cancel all at once.
[0058]
Further, although the amount of misregistration generated in the i-th multiple drawing is offset by one correction operation in the j-th multiple drawing, it may be corrected by being divided into a plurality of multiple drawing after the i-th multiple drawing. .
[0059]
Further, although the case where all the positional deviation amounts are cleared at the j-th multiple drawing has been shown, the positional deviation amount generated at the j-th multiple drawing is further represented by the k-th (N ≧ k> j) and subsequent multiple drawing. You may make it cancel with.
[0060]
Further, the positional deviation amount generated at only one point of the drawing pattern has been described as an example, and the correction operation processing of the positional deviation amount has been described. However, all of the positional deviation amounts that occurred in an arbitrary i-th (N> i ≧ 1) multiple drawing are described. It is also possible to correct and cancel out the positional deviation amount of the drawing pattern.
[0061]
Embodiment 2. FIG.
In the first embodiment, the case where the positional deviation amount with respect to one target pattern position Ro is canceled by the subsequent correction operation has been described. However, different beam drifts (positional deviations) are provided for a plurality of target pattern positions. In the case where an error occurs, the drift error may be minimized by correcting the substantial average value of the misregistration amounts.
[0062]
FIG. 4 is an explanatory view schematically showing an electron beam exposure process according to the second embodiment of the present invention in which the average positional deviation amounts with respect to a plurality of target pattern positions are canceled.
In FIG. 4, the horizontal axis indicates the drawing position P that is the target pattern position, and the vertical axis indicates the beam drift amount A corresponding to the positional deviation amount.
[0063]
P1 and P2 are a plurality of target pattern positions, and A1 and A2 are beam drift amounts with respect to the target pattern positions P1 and P2. Here, only two points P1 and P2 are shown for the sake of convenience, but actually, exposure is performed in a line (continuous) from the target pattern position P1 to P2 in one operation. To do.
[0064]
A0 is an actual beam drift (function) on the line between the points P1 and P2, E1 and E2 are drift correction amounts for canceling the beam drift amounts A1 and A2, and Eo is each drift correction amount E1 and E2. An average drift correction amount D, which is superposed and averaged, is a drift error generated before application of the average drift correction amount Eo.
[0065]
The beam drift A0 is a function depending on the drawing position and time, and is represented by a linear function as shown in the figure, for example.
In this case as well, each value A0, A1, A2, E1, E2, Eo, D, P1, and P2 actually changes two-dimensionally. Shown in the original.
[0066]
Hereinafter, the correction operation according to the second embodiment of the present invention will be described with reference to FIG.
In this case, the drawing substrate 14 is provided with a plurality of reference marks (not shown) whose coordinate positions are known in advance, and the correction operation for canceling the positional deviation amount is performed by the coordinate positions of the plurality of reference marks. It is done using.
[0067]
First, in multiple drawing at an arbitrary i-th (N> i ≧ 1), before drawing at the target pattern position P1 that is the starting point, the reference mark on the drawing substrate 14 is measured to calculate the beam drift amount A1i. .
[0068]
Next, the calculated beam drift amount A1i is set as the drift correction amount E1, and the i-th drawing is performed in the arrow direction from the start point position P1 to the end point position P2 while correcting the beam drift by the drift correction amount E1.
That is, in the i-th multiple drawing, the drift correction amount E1 is equal to the beam drift amount A1i.
[0069]
Subsequently, when the pattern is drawn at the end point position P2 in the i-th multiple drawing, the reference mark is measured again, and the beam drift amount A2i at the end point position P2 is calculated.
At this time, the beam drift amount A2i changes according to the beam drift A0.
[0070]
As a result, a drift error D is finally generated with respect to the initially set drift correction amount E1.
Therefore, at the end of the i-th drawing, an offset amount between the drift correction amount E1 based on the beam drift amount A1i and the final beam drift amount A2i is obtained as the drift error D.
[0071]
Next, in the j-th (j> i) multiple drawing, before drawing a pattern at the start point position P1, the reference mark is measured in the same manner as described above to calculate the beam drift amount A1j. At this time, since time has elapsed since the i-th multiple drawing, the beam drift amount A1j does not always coincide with A1i.
[0072]
Subsequently, the drift correction amount E2 in which the drift error D is newly added so as to cancel the drift error D generated during the i-th multiple drawing to the calculated beam drift amount A1j is expressed by the following equation (4). To calculate.
[0073]
E2 = A1j + D (4)
[0074]
At this time, the drift correction amount E2 substantially corresponds to the beam drift amount A2j at the end point position P2 in the j-th multiple drawing.
Next, the j-th multiple drawing is performed in the direction of the arrow from the start point position P1 to the end point position P2 while correcting the beam drift with the drift correction amount E2.
[0075]
As a result, the pattern position at the time when the j-th multiple drawing is completed is the center-of-gravity position (average drift correction amount Eo) obtained by superimposing the i-th pattern position.
In this way, by setting the drift correction amount E2 so as to cancel the drift error D at the i-th multiple drawing and performing the j-th drawing, a substantial average at the end point P2 of the j-th multiple drawing is obtained. The drift correction amount Eo is expressed as the following equation (5).
[0076]
Eo = (E1 + E2) / 2 = A1j + D / 2 (5)
[0077]
Therefore, the substantial drift error Dj at the end point position P2 at the end of the jth multiple drawing is expressed as the following equation (6).
[0078]
Dj = Eo−A1j = A1j + D / 2−A1j = D / 2 (6)
[0079]
As apparent from the equation (6), the drift error Dj at the end point position P2 at the end of the j-th multiple drawing is reduced to half compared to the drift error D at the end of the i-th multiple drawing.
[0080]
Further, if a drift error occurs in the j-th multiple drawing, the drawing may be performed with a further drift correction amount set so that the drift error is similarly canceled in the multiple drawing after the j-th.
[0081]
In this way, by correcting the drawing position with a new correction operation and performing drawing during the remaining multiple drawing so as to cancel out the average amount of positional deviation that occurred at the drawing position by multiple drawing multiple times, A highly accurate drawing pattern position in which the shift amount is suppressed can be obtained.
[0082]
Further, using a reference mark whose coordinate position is known in advance, the positional deviation amount of each drawing pattern calculated from the positional deviation amount of the reference mark is corrected, and beam drift (positional deviation amount) caused by deformation of the drawing substrate 14 or the like is corrected. ) Is not affected by substrate deformation and the like, and the reproducibility of the drawing position for each drawing substrate 14 can be improved.
[0083]
Embodiment 3 FIG.
In the first and second embodiments, the beam drift amount (positional deviation amount) generated during arbitrary drawing is only canceled by a subsequent correction operation. However, the predicted beam drift obtained in advance is used. Drift correction may be executed.
[0084]
FIG. 5 is an explanatory view schematically showing an electron beam exposure process according to Embodiment 3 of the present invention using the predicted beam drift.
In FIG. 5, the same components as those described above (see FIG. 4) are denoted by the same reference numerals, and detailed description thereof is omitted.
[0085]
Here, the horizontal axis indicates the time T, the vertical axis indicates the beam drift amount A with respect to the target pattern position, and shows the case where the same drawing positions P1 to P2 (see FIG. 4) are multiple drawn.
[0086]
T1 to T4 are drawing times, T1 and T3 are i-th and j-th drawing start times, and T2 and T4 are i-th and j-th drawing end times, respectively.
[0087]
C1 and C2 are predicted beam drifts (functions), the predicted beam drift C1 corresponds to the multiple drawing at the i-th time (time T1 to T2), and the predicted beam drift C2 is the j-th time (from time T3 to time T3) for the correction operation. This corresponds to multiple drawing in T4).
In this case as well, the values C1 and C2 are shown in only one dimension for simplicity.
[0088]
Hereinafter, the correction operation according to the third embodiment of the present invention will be described with reference to FIG.
First, in the same manner as described above, the reference mark is measured and the beam drift amount is calculated before the i-th multiple drawing.
[0089]
Next, the i-th drawing is performed on the drawing positions P1 to P2 from the drawing start time T1 to the drawing end time T2 using the predicted beam drift C1 corresponding to the beam drift A0 at the drawing positions P1 to P2.
[0090]
Subsequently, after completion of the i-th multiple drawing, the reference mark is measured again to calculate the actual beam drift A0, and the difference between the predicted beam drift C1 and the beam drift A0 is calculated as the drift error D.
[0091]
Next, before the j-th (j> i) multiple drawing, a new predicted beam drift C2 to which the beam drift correction amount E2 is added is calculated so as to cancel the drift error D generated in the i-th multiple drawing. Using this, the j-th drawing is performed on the drawing positions P1 to P2 from the drawing start time T3 to the drawing end time T4. At this time, the drift correction amount E2 is equal to the polarity inversion value (= −D) of the drift error D.
[0092]
As described above, by using the predicted beam drift C2 at the time of drift correction in the j-th multiple drawing, the drift error D generated in the i-th multiple drawing is canceled at the pattern position after the completion of the multiple drawing. Drawing can be realized.
[0093]
In addition, since only the predicted beam drift C2 is changed using the drift correction amount E2 that cancels out the drift error D, there is no need to increase the number of beam drift corrections, and the pattern position accuracy is improved without reducing the throughput. Can be made.
[0094]
Further, by correcting the misalignment amount using the predicted beam drift C2 for the additional operation, the error between the actual beam drift A0 and the predicted beam drift C1 can be eliminated, and the drawing pattern position is further improved in accuracy. can do.
[0095]
Embodiment 4 FIG.
In the third embodiment, the predicted beam drift C2 is corrected for the same drawing positions P1 to P2. However, the predicted beam drift is corrected not only for the drawing positions P1 to P2 but also for different drawing positions. May be.
[0096]
FIG. 6 is an explanatory view schematically showing an electron beam exposure process according to Embodiment 4 of the present invention in which the predicted beam drift is corrected for different drawing positions.
In FIG. 6, the same components as those described above (see FIGS. 4 and 5) are denoted by the same reference numerals, and detailed description thereof is omitted.
[0097]
P3 and P4 are different drawing positions, A3 is a beam drift with respect to the drawing positions P3 to P4, C3 is a predicted beam drift with respect to the drawing positions P3 to P4, C4 is a predicted beam drift after correction with respect to the drawing positions P3 to P4, and D1 is the i-th time. D2 is the drift error at the drawing position P2, D2 is the drift error at the i-th drawing position P4, and E4 is the drift correction amount for P3 to P4 in the j-th multiple drawing.
[0098]
Hereinafter, the correction operation according to the fourth embodiment of the present invention will be described with reference to FIG.
First, as described above, while performing correction using the predicted beam drift C1, the i-th multiple drawing is performed with respect to the drawing positions P1 to P2, and after the drawing position P2 is drawn, the predicted beam drift C1 and the actual beam drift A0. The drift error D1 is calculated.
[0099]
Subsequently, the i-th multiple drawing with respect to the drawing positions P3 to P4 is performed while correcting using the predicted beam drift C3. After drawing of the drawing position P4, the drift error between the predicted beam drift C3 and the actual beam drift A3 is performed. D2 is calculated.
[0100]
Next, at the j-th (j> i) multiplex drawing, a new predicted beam drift C2 to which the drift correction amount E2 is added is obtained so as to cancel out the drift error D1 generated at the i-th multiplex drawing, and the predicted beam Drawing is performed on the drawing positions P1 to P2 using the drift C2.
[0101]
Similarly, with respect to the drawing positions P3 to P4, using the new predicted beam drift C4 to which the drift correction amount E4 is added so as to cancel the drift error D2 generated at the i-th multiple drawing, the drawing positions P3 to P4 are used. The j-th drawing for P4 is performed. At this time, the drift correction amount E4 is equal to the polarity inversion value (= −D2) of the drift error D2.
[0102]
As a result, the pattern position after the completion of the j-th multiple drawing is formed at the center of gravity where all the multiple drawings are superimposed.
In this way, by performing drawing while correcting the drawing position by a plurality of new correction operations during the remaining multiple drawing so as to cancel the amount of misalignment occurring at a plurality of locations, for example, the i-th multiple Since the drift errors D1 and D2 generated in the drawing are canceled and eliminated in the j-th multiple drawing, high-precision drawing pattern position accuracy can be obtained.
[0103]
Note that here, the drift error is eliminated at two positions from the drawing position P1 to the drawing position P2 and from the drawing position P3 to the drawing position P4. The drift error can be eliminated in the region by the same procedure.
[0104]
In addition, the drift errors D1 and D2 are eliminated by controlling the beam drifts C2 and C4 for additional operations. However, during the j-th multiple drawing, the drift error is corrected using correction coefficients for a plurality of drawing positions. The drift error may be eliminated by using a new drawing position correction coefficient added so as to cancel.
[0105]
Embodiment 5 FIG.
In the first to fourth embodiments, an additional operation (see steps S12 and S3 in FIG. 3) is performed so as to cancel the beam drift amount (drift error). However, the target pattern position (step in FIG. 3) is performed. The correction coefficient may be additionally reflected on the S)) to substantially cancel the beam drift amount.
[0106]
FIG. 7 is an explanatory view schematically showing an electron beam exposure process according to Embodiment 5 of the present invention in which a correction coefficient is reflected on the target pattern position.
In FIG. 7, Q0, Q1, Q2, Q3, and Q4 are reference marks formed on the drawing substrate 14, and the coordinate positions of the reference mark positions Q0 to Q4 are measured and known in advance.
[0107]
Po is the outermost peripheral pattern position of the target pattern area to be drawn on the drawing substrate 14, Pi is the outermost peripheral pattern position at the i-th multiple drawing, Pj is the outermost peripheral pattern at the j-th (j> i) multiple drawing. Position.
[0108]
Hereinafter, the correction operation according to the fifth embodiment of the present invention will be described with reference to FIG.
First, before the i-th multiple drawing, the positions of the reference marks Q0 to Q4 are measured by the electron beam exposure apparatus, and compared with the reference mark positions measured in advance, the positions of the reference marks Q0 to Q4 before the electron beam exposure. Find the amount of deviation.
[0109]
Next, the drawing position correction defined for each drawing position so as to correct the positional deviation amount for each pattern drawing position calculated from the positional deviation amounts of the reference marks Q0 to Q4 during the i-th multiple drawing. Drawing is performed after the drawing position is corrected by the coefficient.
[0110]
For example, experimentally, the position of each reference mark Q0 to Q4 is measured after completion of the i-th multiple drawing, and the amount of change in the distance between each reference mark before and after the i-th multiple drawing is obtained. It has been found that the distance between the reference marks is extended after the end of multiple drawing.
[0111]
As described above, when a pattern is drawn on the substrate with the distance between the reference marks extended immediately before the end of the i-th multiple drawing, the outermost peripheral pattern position Pi drawn for the i-th time is inside the outermost peripheral pattern position Po to be drawn. Thus, a displacement amount is generated between the drawing pattern position Pi and the pattern position Po to be drawn.
[0112]
Although simplified in FIG. 7, in practice, since the substrate is gradually deformed during the i-th drawing, the amount of displacement at each drawing position becomes complicated. For example, the reference mark Qo In many cases, the corresponding center position is shifted.
[0113]
Accordingly, the amount of misregistration for each pattern drawing position is calculated, and the reference marks Q0 to Q4 are measured before the subsequent j-th multiple drawing, and based on the obtained misregistration amounts of the reference marks Q0 to Q4. Then, drawing is performed so as to correct the amount of misalignment at each pattern drawing position.
[0114]
That is, as the j-th drawing position correction coefficient, the drawing position correction coefficient to which a new correction is added is used so as to cancel the positional deviation amount generated in the i-th multiple drawing, and the j-th drawing is performed while correcting the drawing position. I do.
[0115]
In this case, the outermost peripheral pattern position Pj of the drawing pattern by the j-th multiple drawing is drawn outside the outermost peripheral pattern position Po of the drawing pattern to be drawn.
At this time, the substantial pattern position after the completion of the j-th multiple drawing is a position where all the multiple drawings are superimposed.
[0116]
Therefore, the amount of misregistration generated in the i-th multiple drawing is canceled by the j-th multiple drawing and becomes substantially zero, so that a high-precision drawing pattern position accuracy can be obtained.
[0117]
At this time, since drawing is performed with reference to the reference marks whose coordinate positions of the reference marks Q0 to Q4 are known in advance, it is possible to perform drawing while correcting substrate deformation for each drawing substrate 14, and the like. The reproducibility of each drawing position can be improved.
[0118]
In the fifth embodiment, the case where the amount of misalignment that occurs is an extension of the distance between the reference marks has been described, but the amount of misalignment that can occur may be any other parameter, Not only primary components such as drift, rotation, orthogonality, etc. but also higher-order components of the second or higher order can be corrected and canceled by the drawing position correction coefficient.
[0119]
In the fifth embodiment, the positional deviation amount is corrected using only the drawing position correction coefficient. However, the positional deviation amount may be corrected using both the drawing position correction coefficient and beam drift correction.
[0120]
Furthermore, you may combine the said Embodiment 1-5 arbitrarily as needed, thereby, each effect can be show | played in a superimposed manner and the further high precision can be implement | achieved.
[0121]
【Effect of the invention】
As described above, according to the first aspect of the present invention, in the electron beam exposure apparatus that performs multiple drawing by irradiating the drawing substrate with the electron beam a plurality of times, the start and end of the multiple drawing are performed. I-th drawing The actual drawing position on the generated drawing board Ri And target pattern position Ro Misalignment (Ri-Ro) Misregistration amount determination means for determining whether or not there is multiple drawing, and the amount of misalignment that occurred during multiple drawing (Ri-Ro) For later multiple drawing In the jth drawing (j> i) Correction operation means for correcting the drawing position during the remaining multiple drawing included in the multiple drawing so as to cancel The correction operation means determines the j-th drawing position R) in the correction scan by the following equation, Rj = Ro− (Ri−Ro). Therefore, there is an effect that an electron beam exposure apparatus that achieves high-precision pattern drawing position accuracy while minimizing a decrease in throughput is obtained.
[0122]
According to claim 2 of the present invention, in claim 1, the correction operation means performs the remaining multiple drawing operations so as to cancel out misalignment amounts generated at a plurality of locations from the start to the end of the multiple drawing. Since the drawing position correction operation is performed only a plurality of times in the meantime, there is an effect that an electron beam exposure apparatus that realizes high-precision pattern drawing position accuracy while minimizing a decrease in throughput can be obtained.
[0123]
According to a third aspect of the present invention, in the first or second aspect, the correction operation means performs the remaining multiple drawing so as to cancel the average misalignment amount generated a plurality of times at the drawing position by the multiple drawing. Since the drawing position correction operation is performed during this period, the final positional deviation amount can be suppressed, and an electron beam exposure apparatus that realizes high-precision pattern drawing position accuracy while minimizing throughput reduction Is effective.
[0124]
According to a fourth aspect of the present invention, in the third aspect, the correction operation means performs the correction operation by dividing the remaining multiple drawing into a plurality of times so as to cancel out the positional deviation amount generated at the drawing position. Thus, there is an effect that an electron beam exposure apparatus that realizes high-precision pattern drawing position accuracy while minimizing a decrease in throughput can be obtained.
[0125]
According to claim 5 of the present invention, in any one of claims 1 to 4, the correction operation means performs the correction operation using the correction coefficient for the drawing position, so that the accuracy can be further increased. There is an effect that an electron beam exposure apparatus that realizes a precise pattern drawing position accuracy can be obtained.
[0126]
According to claim 6 of the present invention, in any one of claims 1 to 5, the correction operation means performs the correction operation using electron beam drift correction. The effect of obtaining an electron beam exposure system that can cancel the drift error due to the variation of the pattern and the writing position, and the drift error due to the temperature change with time, and realize the high precision pattern drawing position accuracy while minimizing the decrease in throughput. is there.
[0127]
According to claim 7 of the present invention, in claim 6, since the correction operation means performs the drift correction using the predicted beam drift, the electron beam realizing higher precision pattern drawing position accuracy. There is an effect that an exposure apparatus can be obtained.
[0128]
According to an eighth aspect of the present invention, in the sixth or seventh aspect, the drawing board has a plurality of reference marks whose coordinate positions are known in advance, and the correction operation means is the coordinate position of the reference mark. Since the drift correction is performed by using the reference mark, an electron beam exposure apparatus that achieves a high-precision pattern drawing position accuracy using a reference mark that is normally provided can be obtained.
[0129]
According to claim 9 of the present invention, in claim 8, the correction operation means performs the correction operation using the correction coefficient for the drawing position obtained from the coordinate position of the reference mark. There is an effect that an electron beam exposure apparatus that realizes high-precision pattern drawing position accuracy can be obtained.
[0130]
According to a tenth aspect of the present invention, in any one of the first to ninth aspects, the drawing substrate has a plurality of reference marks whose coordinate positions are known in advance, and the correction operation means includes a plurality of correction operation means. Since the correction operation is performed using the coordinate position of the reference mark, it is possible to obtain an electron beam exposure apparatus that realizes a higher precision pattern drawing position accuracy by using the normally provided reference mark.
[Brief description of the drawings]
FIG. 1 is a block configuration diagram schematically showing Embodiment 1 of the present invention;
FIG. 2 is an explanatory view schematically showing an electron beam exposure process according to Embodiment 1 of the present invention.
FIG. 3 is a flowchart showing a correction operation according to Embodiment 1 of the present invention.
FIG. 4 is an explanatory view schematically showing an electron beam exposure process according to Embodiment 2 of the present invention.
FIG. 5 is an explanatory view schematically showing an electron beam exposure process according to Embodiment 3 of the present invention.
FIG. 6 is an explanatory view schematically showing electron beam exposure processing according to Embodiment 4 of the present invention.
FIG. 7 is an explanatory view schematically showing electron beam exposure processing according to Embodiment 5 of the present invention.
FIG. 8 is a flowchart showing a specific operation of multiple drawing processing by a conventional electron beam exposure apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Target pattern position calculation means, 11 Position shift amount determination means, 12 Correction operation means, 13 Electron beam irradiation means, 14 Drawing board, A, A1, A2 Beam drift amount, A0, A3 Beam drift, B Electron beam, C1 C4 Predicted beam drift, D, D1, D2 drift error, E1, E2, E4 drift correction amount, Eo average drift correction amount, P, P1 to P4 drawing position, Q0 to Q4 reference mark, Ro target pattern position, Ri i-th time Drawing position, Rj j-th drawing position, S12 performing additional correction operation, and S13 determining the amount of displacement.

Claims (10)

In an electron beam exposure apparatus that performs multiple drawing by irradiating an electron beam onto a drawing substrate multiple times,
Presence / absence of a positional deviation amount (Ri-Ro) between the actual drawing position (Ri) on the drawing substrate and the target pattern position (Ro) generated in the i-th drawing from the start to the end of the multiple drawing. Misregistration amount judging means for judging during multiple drawing,
Positional deviation amount generated during the multiple draws (Ri-Ro), to cancel the drawing of j th of definitive to multiple writing (j> i) after, during the remainder of the multiple drawing included in the multiple writing Correction operation means for performing a correction operation of the drawing position ,
The correction operation means calculates the j-th drawing position (Rj) in the correction scan by the following equation:
Rj = Ro- (Ri-Ro)
Electron beam exposure apparatus characterized by determining by.   The correction operation means performs the drawing position correction operation only a plurality of times during the remaining multiple drawing so as to cancel out misregistration amounts generated at a plurality of locations from the start to the end of the multiple drawing. The electron beam exposure apparatus according to claim 1.   The correction operation means performs a correction operation of the drawing position during the remaining multiple drawing so as to cancel an average amount of misalignment that occurs a plurality of times at the drawing position by the multiple drawing. The electron beam exposure apparatus according to claim 1 or 2.   4. The electron beam according to claim 3, wherein the correction operation unit performs the correction operation by dividing the remaining multiple drawing into a plurality of times so as to cancel out a positional deviation amount generated at the drawing position. Exposure device.   The electron beam exposure apparatus according to claim 1, wherein the correction operation unit performs the correction operation using a correction coefficient for the drawing position.   6. The electron beam exposure apparatus according to claim 1, wherein the correction operation means performs the correction operation using drift correction of the electron beam.   The electron beam exposure apparatus according to claim 6, wherein the correction operation unit performs the drift correction using a predicted beam drift. The drawing substrate has a plurality of reference marks whose coordinate positions are known in advance,
The electron beam exposure apparatus according to claim 6, wherein the correction operation unit performs the drift correction using a coordinate position of the reference mark.   9. The electron beam exposure apparatus according to claim 8, wherein the correction operation means performs the correction operation using a correction coefficient for the drawing position obtained from the coordinate position of the reference mark. The drawing substrate has a plurality of reference marks whose coordinate positions are known in advance,
The electron beam exposure apparatus according to claim 1, wherein the correction operation unit performs the correction operation using coordinate positions of the plurality of reference marks.

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