JP2012231094A - Charged particle beam drawing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress an extreme change in a drift correction amount among stripe regions so as to improve the state of connection between the stripe regions.SOLUTION: A charged particle beam drawing apparatus 1 comprises: a drift measurement part 39 measuring a drift amount of a charged particle beam in each correction section where the drift of the charged particle beam is corrected; a predicted drawing time calculation part 37 calculating a predicted drawing time in each stripe region on a sample W: a drawing stripe number calculation part 33a calculating the number of drawing stripes, which is the number of stripe regions for being objects of drawing inside the correction section, by using the calculated predicted drawing time in each stripe region; a drift correction amount calculation part 33b calculating a drift correction amount in each stripe region in the correction section by dividing the drift amount by the calculated number of drawing stripes; and a deflection control part 35 being an example of a drift correction part correcting the drift of the charged particle beam in each stripe region by using the calculated drift correction amount in each stripe region.

Description

  The present invention relates to a charged particle beam drawing apparatus.

  With the recent high integration and large capacity of large scale integrated circuits (LSIs), circuit line widths required for semiconductor devices are becoming increasingly smaller. In order to form a desired circuit pattern on a semiconductor device, a lithography technique is used. In this lithography technique, pattern transfer using an original pattern called a mask (reticle) is performed. In order to manufacture a high-accuracy mask used for this pattern transfer, a charged particle beam drawing apparatus having an excellent resolution is used.

  As this charged particle beam drawing apparatus, for example, a pattern to be drawn on a sample such as a mask is divided into a plurality of stripe regions, each stripe region is divided into a number of sub-regions, and the stage on which the sample is placed is striped. A drawing apparatus has been developed that moves an electron beam in the longitudinal direction of an area, positions an electron beam in each sub-area by main deflection, and draws a figure by shooting at a predetermined position in the sub-area by sub-deflection.

  In such a charged particle beam drawing apparatus, a phenomenon called beam drift may occur in which the beam position shifts over time due to various factors during drawing. The drift correction that corrects this drift is for canceling the beam drift, and in order to maintain the connection between the stripe regions, instead of correcting the entire amount of the measured drift amount suddenly, the main deflection is applied at the head of the stripe region. While adding correction values to the coordinates, they are corrected little by little linearly in time proportion.

  Here, regarding drift correction, a technique for determining the next measurement start time according to the change rate of the drift amount and measuring and correcting the drift amount at that time (see, for example, Patent Document 1), or a transfer pattern Is divided into a plurality of regions and a drift correction time interval is determined for each region (see, for example, Patent Document 2). Further, the drift correction is repeated until the drift amount falls within a predetermined threshold value before drawing. A technique to start (for example, see Patent Document 3) has been proposed.

Japanese Patent Laid-Open No. 7-142321 JP-A-9-260247 Japanese Patent Laid-Open No. 10-199786

  However, the drawing time for each stripe region described above is not constant, and a large difference may occur between adjacent stripe regions. Due to this difference in drawing time, the amount of change in drift correction amount between stripe regions, that is, the amount of change in correction. Therefore, the drift correction amount changes extremely between the stripe regions. Since this drift correction amount is added to the main deflection coordinates, an extreme change in the drift correction amount between the stripe regions adversely affects the connection between the stripe regions, and the connection state deteriorates.

  The problem to be solved by the present invention is to provide a charged particle beam drawing apparatus capable of suppressing an extreme change in the amount of drift correction between stripe regions and improving the connection state between stripe regions.

  According to an embodiment of the present invention, in a charged particle beam drawing apparatus, a drawing unit that divides a pattern to be drawn on a sample into a plurality of stripe regions and performs drawing with a charged particle beam for each stripe region, and a charged particle beam A drift measurement unit that measures a drift amount of a charged particle beam for each correction section for correcting drift, a drawing prediction time calculation unit that calculates a drawing prediction time for each stripe region, and a stripe region calculated by a drawing prediction time calculation unit A drawing stripe number calculation unit that calculates the number of drawing stripes, which is the number of stripe regions to be drawn within the correction section, using the estimated drawing time for each drawing, and the number of drawing stripes calculated by the drawing stripe number calculation unit are used. The drift amount measured by the drift measurement unit is divided to compensate for the drift in each stripe area within the correction interval. Comprising a drift correction amount calculating unit for calculating an amount, by using the drift correction amount of each stripe region calculated by the drift correction amount calculating unit, and a drift correction unit that corrects the drift of the charged particle beam for each stripe region.

  In the charged particle beam drawing apparatus, it is preferable that the drift correction amount calculation unit adds 1 to the number of drawing stripes calculated by the drawing stripe number calculation unit and divides the drift amount using the value.

  In the charged particle beam drawing apparatus, the drift correction amount calculation unit desirably divides the drift amount using the number of drawing stripes calculated by the drawing stripe number calculation unit as it is.

  In the charged particle beam drawing apparatus, a stripe division determination unit that determines whether or not the drawing prediction time calculated by the drawing prediction time calculation unit is equal to or longer than the correction interval, and a drawing prediction time that is longer than the correction interval by the stripe division determination unit When it is determined that the stripe region is a stripe dividing unit that divides the stripe region whose drawing prediction time is longer than the correction interval in the short direction.

  Further, in the charged particle beam drawing apparatus, the drift measurement unit starts measuring the drift amount in response to the drawing interruption in the correction interval, and the drawing stripe number calculation unit performs the remaining correction interval from the cancellation of the drawing interruption. The number of drawn stripes, which is the number of stripe regions to be drawn within, is calculated, and the drift correction amount calculating unit uses the number of drawn stripes calculated by the drawn stripe number calculating unit to measure the drift measured by the drift measuring unit. It is desirable to divide the quantity.

  According to the present invention, it is possible to suppress an extreme change in the drift correction amount between the stripe regions and improve the connection state between the stripe regions.

1 is a diagram showing a schematic configuration of a charged particle beam drawing apparatus according to a first embodiment of the present invention. It is explanatory drawing for demonstrating the drawing data which a charged particle beam drawing apparatus uses. It is explanatory drawing for demonstrating the flow of a series of drawing operation | movement which a charged particle beam drawing apparatus performs. It is explanatory drawing for demonstrating the calculation process of the number of drawing stripes. It is the 1st explanatory view for explaining calculation processing of the drift correction amount. It is the 2nd explanatory view for explaining calculation processing of the drift amendment amount. It is explanatory drawing for demonstrating the calculation process of the drift correction amount of a 1st comparative example. It is explanatory drawing for demonstrating the calculation process of the drift correction amount of a 2nd comparative example. It is a figure which shows schematic structure of the charged particle beam drawing apparatus which concerns on the 2nd Embodiment of this invention. It is explanatory drawing for demonstrating the division | segmentation process of a stripe area | region. It is the 3rd explanatory view for explaining calculation processing of the drift correction amount. It is the 4th explanatory view for explaining calculation processing of the drift correction amount.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the charged particle beam drawing apparatus 1 according to the first embodiment of the present invention includes a drawing unit 2 that performs drawing using a charged particle beam, and a control unit 3 that controls the drawing unit 2. ing. The charged particle beam drawing apparatus 1 is an example of a variable shaping type drawing apparatus using, for example, an electron beam as a charged particle beam. The charged particle beam is not limited to the electron beam, and may be another charged particle beam such as an ion beam.

  The drawing unit 2 includes a drawing chamber 2a that houses a sample W to be drawn, and an optical barrel 2b that communicates with the drawing chamber 2a. A stage 11 that supports the sample W is provided in the drawing chamber 2a. The stage 11 is formed so as to be movable in the X and Y directions perpendicular to each other in a horizontal plane, and a sample W such as a mask or a blank is placed on the placement surface of the stage 11. In the optical barrel 2b, an electron gun 21 for emitting an electron beam B, an illumination lens 22 for condensing the electron beam B, a first shaping aperture 23 for beam shaping, and a projection for projection are provided. A lens 24, a shaping deflector 25 for beam shaping, a second shaping aperture 26 for beam shaping, an objective lens 27 for focusing the beam on the sample W, and a beam shot position for controlling the sample W A main deflector 28 and a sub deflector 29 are arranged.

  In the drawing unit 2, the electron beam B is emitted from the electron gun 21 and is irradiated onto the first shaping aperture 23 by the illumination lens 22. The first shaping aperture 23 has, for example, a rectangular opening. Thereby, when the electron beam B passes through the first shaping aperture 23, the cross-sectional shape of the electron beam is shaped into a rectangular shape and projected onto the second shaping aperture 26 by the projection lens 24. The projection position can be deflected by the shaping deflector 25, and the shape and size of the electron beam B can be controlled by changing the projection position. Thereafter, the electron beam B that has passed through the second shaping aperture 26 is irradiated with the focus of the electron beam B being adjusted to the sample W on the stage 11 by the objective lens 27. The shot position of the electron beam B with respect to the sample W on the stage 11 can be controlled by the main deflector 28 and the sub deflector 29.

  The control unit 3 controls the movement of the stage 11, a job (JOB) control unit 31 that controls the entire drawing operation, a shot data generation unit 32 that generates shot data, a drawing control unit 33 that controls drawing, and the like. A stage control unit 34, a deflection control unit 35 that controls the shaping deflector 25, the main deflector 28, and the sub deflector 29, a drawing data storage unit 36 that stores drawing data, and a drawing prediction time required for drawing are calculated. A predicted drawing time calculation unit 37, a predicted drawing time data storage unit 38 that stores predicted drawing time data, a drift measurement unit 39 that measures the drift amount of the electron beam B, and stores the measured drift amount as drift measurement result data. The drift measurement result data storage unit 40 is provided. The drawing control unit 33 includes a drawing stripe number calculation unit 33a that calculates the number of drawing stripes and a drift correction amount calculation unit 33b that calculates a drift correction amount (details will be described later). Note that the above-described units are configured by hardware, software, or both.

  As shown in FIG. 2, the shot data generation unit 32 divides the pattern P defined by the drawing data into a plurality of stripe regions (frame regions) R1 in a stripe shape (strip shape), and further each stripe region R1. The matrix is divided into a large number of sub-regions (block regions) R2. In addition, the shot data generation unit 32 determines the shape, size, position, and the like of the figure Z in each sub-region R2, and if the figure Z cannot be drawn with a single shot, the drawing is generated. The shot data is generated by dividing into a plurality of possible partial areas. The length of the stripe region R1 in the short direction (Y direction) is set to a length that allows the electron beam B to be deflected by main deflection.

  When drawing the above-described pattern P, the drawing control unit 33 moves the stage 11 in the longitudinal direction (X direction) of the stripe region R1 via the stage control unit 34, while passing the electron through the deflection control unit 35. The beam is positioned in each sub-region R2 by the main deflector 28, and the electron beam B is shot at a predetermined position in the sub-region R2 by the sub-deflector 29 to draw the figure Z. Thereafter, when the drawing of one stripe region R1 is completed, the stage 11 is moved stepwise in the Y direction, and then the next stripe region R1 is drawn. This is repeated and the pattern P is drawn on the entire drawing region of the sample W. To do. Since the stage 11 is continuously moving in one direction during drawing, the drawing origin of the sub-region R2 is tracked by the main deflector 28 so that the drawing origin follows the movement of the stage 11. Yes.

  Thus, the irradiation position of the electron beam B is determined while following the stage 11 which is deflected by the main deflector 28 and the sub deflector 29 and continuously moves. The drawing time can be shortened by continuously moving the stage 11 in the X direction and making the shot position of the electron beam B follow the movement of the stage 11. However, in the embodiment of the present invention, the movement of the stage 11 in the X direction is continuously performed. However, the present invention is not limited to this. For example, the drawing of one sub-region R2 is performed with the stage 11 stopped. However, when moving to the next sub-region R2, a step-and-repeat drawing method in which drawing is not performed may be used.

  The stage control unit 34 is a control unit that controls the movement of the stage 11 in accordance with the control by the drawing control unit 33. The deflection control unit 35 is a control unit that controls the main deflector 28 and the sub deflector 29 in addition to the shaping deflector 25 in accordance with the control by the drawing control unit 33. The deflection control unit 35 functions as a drift correction unit that controls the deflection amount of the electron beam B and corrects the drift of the electron beam B.

  The drawing data storage unit 36 is a storage unit that stores drawing data that is pattern data (layout data) that defines the pattern P described above. The drawing data is input from outside the apparatus and stored in the drawing data storage unit 36. Also, the predicted drawing time calculation unit 37 calculates the predicted drawing time for each stripe region R1 using the drawing data, and stores it in the predicted drawing time data storage unit 38 as predicted drawing time data.

  The drift measurement unit 39 scans and detects a reference mark (not shown) on the stage 11 to obtain the drift amount of the electron beam B from the difference between the current mark position and the previous mark position. The drift amount is stored in the drift measurement result data storage unit 40 as drift measurement result data. Here, the reference mark is a mark for measuring the drift amount, and is formed on the surface of the stage 11. For example, the reference mark is formed in a cross shape, and is formed of a material having a reflectance different from that of the surface. The measuring means for measuring the drift amount may be any means that can measure the drift amount, and the means is not particularly limited.

  Next, a series of drawing operations performed by the charged particle beam drawing apparatus 1 will be described.

  The job control unit 31 sends a “shot generation start instruction” to the shot data generation unit 32 in response to the occurrence of a job. Upon receiving the “shot generation start instruction”, the shot data generation unit 32 starts generating shot data. Further, the job control unit 31 sends a “drawing start instruction” to the drawing control unit 33. Upon receiving the “drawing start instruction”, the drawing control unit 33 inquires the shot data generation unit 32 about the progress status of the shot data generation. If drawing is possible, the drawing control unit 33 controls the stage control unit 34 and the deflection control unit 35. While drawing the stripe. Drift measurement is executed a predetermined number of times during the stripe drawing. In addition, although the start time of drift measurement is set with a random period, it is not restricted to this, For example, you may set with a fixed period.

  When the current time reaches the drift measurement start time, as shown in FIG. 3, the drift measurement unit 39 sends a “drift measurement permission request” to the job control unit 31 (step S1). The job control unit 31 receives the “drift measurement permission request” and sends a “drawing pause instruction” to the drawing control unit 33 (step S2). The drawing control unit 33 receives the “drawing pause instruction”, stops drawing (step S3), and sends “drawing pause completion” to the job control unit 31 (step S4). The job control unit 31 receives the “drawing pause completion” and sends “drift measurement permission” to the drift measurement unit 39 (step S5).

  The drift measurement unit 39 receives the “drift measurement permission” and performs drift measurement (step S6). That is, the drift measurement unit 39 sends a “move instruction to the measurement mark position” to the stage control unit 34 and further sends a “mark scan instruction” to the deflection control unit 35 to measure the mark position. Next, the drift measurement unit 39 obtains a drift amount (total correction amount in the correction section) from the difference between the measured current mark position and the previous mark position, and saves it in the drift measurement result data storage unit 40 as drift measurement result data. To do. Thereafter, the drift measurement unit 39 sends “drift measurement complete” to the job control unit 31 (step S7). The drift measurement result data includes, for example, X-direction offset value, Y-direction offset value, X-direction coefficient, Y-direction coefficient, measurement date, measurement time, X-direction limit value, Y-direction limit value, etc. Is included. Note that the drift amount is defined by the time and coefficient of the correction interval.

  The job control unit 31 receives the “drift measurement completion” and sends a “drawing restart instruction” to the drawing control unit 33 (step S8). The drawing control unit 33 receives the “drawing resumption instruction”, reads the drift measurement result data from the drift measurement result data storage unit 40, resumes drawing (step S9), and instructs the job control unit 31 to “complete drawing resumption”. Return (step S10).

  The drawing control unit 33 requests time distribution data from the shot data generation unit 32 in response to the resumption of drawing described above, and after acquiring the time distribution data, determines an optimal stage speed profile from the time distribution data. . Next, the drawing control unit 33 inquires of the shot data generation unit 32 about the preparation status of the shot data, and upon receiving “shot start permission” from the shot data generation unit 32, the drawing control unit 33 sets the stage speed profile to the stage control unit. Set to 34.

  In addition, when the job control unit 31 receives the above-mentioned “drawing completion”, it sends “next drift measurement start time (scheduled time)” to the drawing control unit 33 (step S11). The drawing control unit 33 receives the “start time of the next drift measurement” and uses the drawing stripe number calculation unit 33a and the drift correction amount calculation unit 33b to use the drift correction amount for each stripe region R1 existing in the correction section. Is calculated (step S12), and stripe drawing is performed while correcting the drift of the electron beam B using the drift correction amount (drift correction value) (step S13).

  In step S12 described above, the drawing control unit 33 passes the “start time of the next drift measurement” received from the job control unit 31 to the drawing stripe number calculation unit 33a. The drawing stripe number calculation unit 33a receives the “next drift measurement start time”, and further reads the drawing prediction time data from the drawing prediction time data storage unit 38, and from “the current drift measurement start time” to “next time”. The number of drawn stripes, which is the number of stripe regions R1 to be drawn within the correction section up to “the start time of the drift measurement”, is calculated. Thereafter, the drawing stripe number calculation unit 33a sends the calculated drawing stripe number to the drift correction amount calculation unit 33b. The predicted drawing time data includes, for example, a column number, a stripe number for each stripe region R1, a predicted writing time, and the like.

  For example, as shown in FIG. 4, the drawing stripe number calculation unit 33a includes the predicted drawing time A1 of the first stripe region R1, the estimated drawing time A2 of the second stripe region R1, and the third in the current correction section L. It is determined that the drawing predicted time A3 of the stripe region R1 and the predicted drawing time A4 of the fourth stripe region R1 are included, and the number of drawing stripes to be drawn within the correction section L is calculated as four. Thereafter, the drawing stripe number calculation unit 33a passes the calculated numerical value 4 to the drift correction amount calculation unit 33b. Here, the first to fourth stripe regions R1 are regions arranged in order in the short direction (main deflection direction). In addition, since the start time of the drift measurement is set at a random cycle, the length (time length) of the correction section L also changes. However, the start time of the drift measurement may be set at a constant cycle. In this case, the length of the correction section L is also constant.

  Next, the drift correction amount calculation unit 33b receives the number of drawing stripes from the drawing stripe number calculation unit 33a, and calculates the drift correction amount for each stripe region R1 existing in the correction section L using the numerical value. Specifically, the drift correction amount calculation unit 33b equally divides the total correction amount in the correction section, which is the drift amount measured by the drift measurement unit 39, using the received number of drawn stripes, and uses the division result. The drift correction amount for each stripe region R1 in the correction section L is calculated. However, although it is desirable to divide the total correction amount in the correction section equally, the present invention is not limited to this. The allowable range is a range in which the deterioration of the connection between the stripe regions R1 can be suppressed, and various kinds of data such as drawing data (pattern P), the size of the stripe region R1, and the size of the sub-region R2 can be used. It will be decided according to the factors.

  Here, for example, as shown in FIG. 5, when the number of drawing stripes is 4, the drift correction amount calculation unit 33b adds 1 to the number of drawing stripes 4 in order to obtain the correction change amount h. A correction change amount h is calculated by dividing the total correction amount H in the correction section by 5 of the addition result (h = H / 5). At this time, since the total correction amount H in the correction section is equally divided, the correction change amount h is the same in each of the first to fourth stripe regions R1. However, there is a correction remainder h (upper right in FIG. 5). The correction amount (correction value) at the start point of the correction section (the start time of the current drift measurement) is the correction section offset value h0, and this correction section offset value h0 is obtained from the drift measurement result.

  Thereafter, the drift correction amount calculation unit 33b calculates the drift correction amount by adding the correction interval offset value h0 to the above-described correction change amount h in order to obtain the drift correction amount of the first stripe region R1. Similarly, the drift correction amount of the second stripe region R1 is also obtained by multiplying the aforementioned correction change amount h by the stripe number No. 2, and adding the correction section offset value h0 to the value of the multiplication result. That is, the drift correction amount of the second stripe region R1 is a value obtained by adding the correction change amount h to the drift correction amount of the first stripe region R1. The drift correction amount of the third stripe region R1 is also obtained by multiplying the correction change amount h by the stripe number 3 and adding the correction section offset value h0 to the value of the multiplication result. That is, the drift correction amount of the third stripe region R1 is a value obtained by adding the correction change amount h to the drift correction amount of the second stripe region R1. The drift correction amount of the fourth stripe region R1 is calculated similarly.

  Also, for example, as shown in FIG. 6, when the number of drawn stripes is 1, that is, when the predicted drawing time A1 of the first stripe region R1 is equal to or longer than the correction section L, the drift correction amount calculating unit 33b In order to obtain the correction change amount h, 1 is added to 1 of the number of drawn stripes, and the correction change amount h is calculated by dividing the total correction amount H in the correction section by 2 of the addition result (h = H / 2). At this time, since the total correction amount H in the correction section is equally divided, the correction change amount h and the correction remaining amount h are the same. Thereafter, the drift correction amount calculating unit 33b calculates the drift correction amount of the first stripe region R1 by adding the correction interval offset value h0 to the above-described correction change amount h.

  The calculation of the drift correction amount as described above is summarized as follows. Since it is necessary to determine the drift correction amount with respect to the main deflection coordinates, drift correction amounts (correction amounts dx, dy) are calculated for each of the X direction and the Y direction.

Total correction amount in correction interval Hx = time until next measurement × coefficient X
Total correction amount Hy in the correction section Hy = Time until next measurement × Coefficient Y
Correction change amount hx = total correction amount Hx in correction interval / (number of drawn stripes + 1)
Correction change amount hy = Total correction amount Hy within correction interval / (Number of drawing stripes + 1)
Correction amount dx = correction interval offset value h0x + drawing stripe number in correction interval × correction change amount hx
Correction amount dy = correction interval offset value h0y + drawing stripe number in correction interval × correction change amount hy

  However, if the total correction amount Hx, Hy in the correction section exceeds the limit value, it is replaced with the limit value. It should be noted that adding 1 to the number of drawing stripes in the above formula always means that even if there is only one stripe region R1 in the correction interval L (when the number of drawing stripes is 1), it is always within the correction interval. This is because the total correction amount H is divided into two equal parts (see FIG. 6).

  The drift correction amount calculation unit 33b calculates the drift correction amount (correction amount dx and correction amount dy) for each stripe region R1 as described above, sets the calculated values in the deflection control unit 35, A “start instruction” is sent, and a “drawing movement start instruction” is sent to the stage controller 34 to start stripe drawing. As a result, the correction change amount h of each stripe region R1 in the correction section L becomes constant, and it is possible to suppress the deterioration of stripe linkage due to an extreme change in the drift correction amount between the stripe regions R1.

  Here, as a first comparative example, when the number of drawing stripes is 4, if correction is performed with a time-proportional drift correction amount without dividing the correction interval total correction amount H evenly as described above, FIG. 7, the correction change amounts h1 to h5 of the first to fourth stripe regions R1 are greatly different (particularly, the correction change amount h3 is extremely large). This is because the correction change amount, that is, the drift correction amount is generated at the start time for each stripe region R1, and thus the drift correction amount is affected by the drawing start time of the stripe region R1. On the other hand, as shown in FIG. 5, when the correction change amount h obtained by equally dividing the correction interval total correction amount H is used, the correction change amount h of each of the first to fourth stripe regions R1 is the stripe region. It becomes the same without being affected by the drawing start time of R1. As a result, it is possible to prevent the stripe connection from deteriorating due to an extreme change in the drift correction amount between the stripe regions R1 as compared to the case shown in FIG.

  Furthermore, as a second comparative example, when the number of drawing stripes is 1, if correction is performed with a time-proportional drift correction amount without dividing the correction interval total correction amount H evenly as described above, FIG. As shown in FIG. 4, the correction change amount h1 of the first stripe region R1 is affected by the drawing start time of the stripe region R1, and becomes very small, and the correction remaining h2 of the correction section L becomes extremely large. On the other hand, as shown in FIG. 6, when the correction change amount h obtained by dividing the total correction amount H in the correction section into two is used, the correction change amount h and the remaining correction h in the first stripe region R1 are the same. Become. As a result, compared to the case shown in FIG. 8, it is possible to reduce the remaining correction, and it is possible to mitigate an extreme change in the drift correction amount at the correction section boundary caused by the remaining correction.

  As described above, according to the first embodiment of the present invention, the number of drawn stripes, which is the number of stripe regions R1 to be drawn in the correction section L, is calculated using the estimated drawing time for each stripe region R1. Then, using the calculated number of drawn stripes, the total correction amount H in the correction section, which is the drift amount measured by the drift measuring unit 39, is divided to obtain the drift correction amount for each stripe region R1 in the correction section L. Is calculated. A correction change amount for each stripe region R1 in the correction interval L is obtained by dividing the correction interval total correction amount H, and the correction change amount h is the same without depending on the drawing start time of each stripe region R1. Therefore, it is possible to prevent the drift correction amount from changing significantly in the correction section L. Therefore, an extreme change in the drift correction amount between the stripe regions R1 can be suppressed, and the connection state between the stripe regions R1 can be improved.

  Further, even when there is only one stripe region R1 in the correction section L by adding 1 to the number of drawing stripes calculated by the drawing stripe number calculation unit 33a and dividing the drift amount by using that value. Since the total correction amount H in the correction section can always be divided into two equal parts, the remaining correction can be reduced. As a result, it is possible to suppress an extreme change in the drift correction amount at the correction section boundary due to the remaining correction.

  In addition, when a new event occurs in the correction section L and drawing is interrupted and drawing is resumed after the event ends, the drift measurement unit 39 first drifts in response to the drawing interruption in the correction section L. Start measuring quantity. Thereafter, the drawing stripe number calculation unit 33a calculates the number of drawing stripes, which is the number of stripe regions R1 to be drawn in the remaining correction section L from the cancellation of drawing interruption, and the drift correction amount calculation unit 33b calculates The aforementioned drift amount division is performed using the number of drawn stripes, and the drift correction amount for each stripe region R1 in the correction section L is calculated. In this way, even after resuming drawing, it becomes possible to accurately calculate the drift correction amount for each stripe region R1 in the correction section L, so that an extreme change in the drift correction amount between the stripe regions R1 can be assured. Can be suppressed.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIGS.

  The second embodiment of the present invention is basically the same as the first embodiment. In the second embodiment, differences from the first embodiment will be described, the same parts as those described in the first embodiment will be denoted by the same reference numerals, and the description thereof will also be omitted.

  As shown in FIG. 9, in the second embodiment of the present invention, the shot data generation unit 32 includes a stripe division determination unit 32a. The stripe division determination unit 32a reads the drawing prediction time data from the drawing prediction time data storage unit 38, compares the drawing prediction time of the stripe region R1 where the shot data is generated with the correction section L, and corrects the drawing prediction time. If it is determined that the interval is equal to or longer than the section L, the shot data generation unit 32 is instructed to perform stripe division.

  When the shot data generation unit 32 receives an instruction to perform stripe division, as shown in FIG. 10, the shot data generation unit 32 divides the designated stripe region R1 into, for example, two in the short direction (main deflection direction), and stripe region R1a and stripe A region R1b is generated. The shot data generation unit 32 functions as a stripe division unit that divides the stripe region R1. The number of divisions at this time is included in the instruction from the stripe division determination unit 32a and is a numerical value of at least two.

  Next, a series of drawing operations performed by the charged particle beam drawing apparatus 1 including the above-described stripe division determination unit 32a will be described.

  First, the job control unit 31 sends a “minimum section time” that is the time length of the correction section L to the shot data generation unit 32 together with the “shot generation start instruction” to the shot data generation unit 32 in accordance with the occurrence of the job. send. Upon receiving the “shot generation start instruction”, the shot data generation unit 32 starts shot data generation and passes “minimum section time” to the stripe division determination unit 32a.

  The stripe division determination unit 32a reads the drawing prediction time data from the drawing prediction time data storage unit 38, compares the drawing prediction time of the stripe region R1 where shot data is generated with the “minimum section time”, and the drawing prediction time. If it is equal to or longer than the “minimum section time”, a “stripe division instruction” is passed to the shot data generation unit 32.

  Upon receiving the “stripe division instruction” from the stripe division determination unit 32a, the shot data generation unit 32 divides the stripe region R1, holds the stripe division information, and draws the stripe division information together with normal stripe information. Send to 33. The drawing control unit 33 receives the stripe division information and the stripe information, and passes the stripe division information to the drawing stripe number calculation unit 33a. Note that the stripe division information includes, for example, a column number, a stripe number, and the number of divisions.

  In addition, the job control unit 31 sends a “drawing start instruction” to the drawing control unit 33. Upon receiving the “drawing start instruction”, the drawing control unit 33 inquires the shot data generation unit 32 about the progress status of the shot data generation. If drawing is possible, the drawing control unit 33 controls the stage control unit 34 and the deflection control unit 35. While drawing the stripe.

  Thereafter, the processing is the same as in the first embodiment described above, but in step S12 shown in FIG. 3, the drawing stripe number calculation unit 33a extracts the stripe region R1 corresponding to the stripe division information from the drawing prediction time data. Then, post-division drawing prediction time data reflecting the stripe division information is created and added to the drawing prediction time data. The drawing stripe number calculation unit 33a calculates the number of drawing stripes, which is the number of stripe regions R1 to be drawn within the correction section L, based on the drawing prediction time data including the divided drawing prediction time data. The post-division drawing prediction time data includes, for example, a column number, stripe number, stripe number branch number, drawing prediction time, and the like.

  Here, for example, as shown in FIG. 11, when the number of drawing stripes is 4, the drift correction amount calculation unit 33b uses the number of drawing stripes 4 to calculate the total correction within the correction interval in order to obtain the correction change amount h. A correction change amount h is calculated by dividing the amount H (h = H / 4). At this time, since the total correction amount H in the correction section is equally divided, the correction change amount h is the same in each of the first to fourth stripe regions R1. In this case, as compared with the first embodiment (see FIG. 5), the remaining correction in the correction section L does not occur.

  In addition, for example, when the number of drawing stripes is 1, that is, the drawing predicted time A1 of the first stripe region R1 is equal to or longer than the correction section L (see FIG. 6), the stripe region R1 has two stripes. Divided into regions R1a and R1b (see FIG. 10). As a result, as shown in FIG. 12, the predicted drawing time A1a of the stripe region R1a and the predicted drawing time A1b of the stripe region R1b are included in the correction section L, and the number of drawn stripes is two. The drift correction amount calculation unit 33b calculates the correction change amount h by dividing the total correction amount H in the correction section by 2 of the number of drawn stripes (h = H / 2). At this time, since the total correction amount H in the correction section is equally divided, the correction change amount h is the same in the stripe region R1a and the stripe region R1b. In this case, as compared with the first embodiment (see FIG. 6), the remaining correction in the correction section L does not occur.

  The calculation of the drift correction amount as described above is summarized as follows. Since it is necessary to determine the drift correction amount with respect to the main deflection coordinates, drift correction amounts (correction amounts dx, dy) are calculated for each of the X direction and the Y direction.

Total correction amount in correction interval Hx = time until next measurement × coefficient X
Total correction amount Hy in the correction section Hy = Time until next measurement × Coefficient Y
Correction change amount hx = Total correction amount in correction interval Hx / Number of drawn stripes Correction change amount hy = Total correction amount in correction interval Hy / Number of drawing stripes Correction amount dx = correction interval offset value h0x + drawing stripe number in correction interval × correction change Quantity hx
Correction amount dy = correction interval offset value h0y + drawing stripe number in correction interval × correction change amount hy

  However, if the total correction amount Hx, Hy in the correction section exceeds the limit value, it is replaced with the limit value. In the above formula, unlike the first embodiment, the correction change amounts hx and hy are calculated using the same number without adding 1 to the number of drawn stripes. As a result, it is possible to prevent the occurrence of correction remaining. When the predicted drawing time of the stripe region R1 is equal to or longer than the correction interval L, that is, when the number of drawn stripes is 1, the stripe region R1 is divided into two or more stripe regions R1a and R1b. . Thereby, since two or more stripe regions R1a and R1b always exist in the correction section L, it is possible to surely prevent the occurrence of correction remaining.

  The drift correction amount calculation unit 33b calculates the drift correction amount (correction amount dx and correction amount dy) for each stripe region R1 as described above, sets the calculated values in the deflection control unit 35, A “start instruction” is sent, and a “drawing movement start instruction” is sent to the stage controller 34 to start stripe drawing. As a result, the correction change amount h of each stripe region R1 in the correction section L becomes constant, and it is possible to prevent deterioration of stripe joining due to an extreme change in the drift correction amount between the stripe regions R1. Furthermore, since there is no correction remaining, an extreme change in the drift correction amount at the correction section boundary caused by the remaining correction can be mitigated.

  As described above, according to the second embodiment of the present invention, the same effects as those of the first embodiment can be obtained. Furthermore, by using the number of drawn stripes calculated by the number of drawn stripes calculation unit 33a as it is and dividing the total correction amount H in the correction section, which is the drift amount, the correction remaining in the correction section L is eliminated, resulting in the correction remaining. It is also possible to suppress an extreme change in the drift correction amount at the correction section boundary.

  In addition, when it is determined whether or not the predicted drawing time of the stripe region R1 is equal to or longer than the correction interval L, and it is determined that the predicted drawing time of the stripe region R1 is equal to or longer than the correction interval L, the predicted drawing time is equal to or longer than the correction interval L. By dividing a certain stripe region R1 in the short direction (main deflection direction), when the predicted drawing time of the stripe region R1 is equal to or longer than the correction interval L, the stripe region R1 is divided into two or more stripe regions R1a and R1b. Therefore, two or more stripe regions R1a and R1b always exist in the correction section L. As a result, it is possible to reliably prevent the occurrence of the remaining correction, and thus it is possible to reliably suppress an extreme change in the drift correction amount at the boundary of the correction section due to the remaining correction.

  As mentioned above, although several embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Charged particle beam drawing apparatus 2 Drawing part 2a Drawing room 2b Optical barrel 3 Control part 11 Stage 21 Electron gun 22 Illumination lens 23 1st shaping | molding aperture 24 Projection lens 25 Molding deflector 26 2nd shaping | molding aperture 27 Objective lens 28 Main deflector 29 Sub deflector 31 Job control unit 32 Shot data generation unit 33 Drawing control unit 33a Drawing stripe number calculation unit 33b Drift correction amount calculation unit 34 Stage control unit 35 Deflection control unit 36 Drawing data storage unit 37 Drawing prediction time calculation Section 38 Drawing prediction time data storage section 39 Drift measurement section 40 Drift measurement result data storage section B Electron beam W Sample

Claims (5)

A drawing unit that divides a pattern to be drawn on a sample into a plurality of stripe regions, and performs drawing with a charged particle beam for each stripe region;
A drift measuring unit for measuring a drift amount of the charged particle beam for each correction section for correcting the drift of the charged particle beam;
A drawing prediction time calculation unit for calculating a drawing prediction time for each stripe region;
A drawing stripe number calculation unit that calculates the number of drawing stripes, which is the number of the stripe regions to be drawn in the correction section, using the drawing prediction time for each stripe region calculated by the drawing prediction time calculation unit; ,
A drift that calculates the drift correction amount for each stripe region in the correction section by dividing the drift amount measured by the drift measurement unit using the number of drawing stripes calculated by the drawing stripe number calculation unit. A correction amount calculation unit;
A drift correction unit that corrects drift of the charged particle beam for each stripe region, using the drift correction amount for each stripe region calculated by the drift correction amount calculation unit;
A charged particle beam drawing apparatus comprising:   2. The charge according to claim 1, wherein the drift correction amount calculation unit adds 1 to the drawing stripe number calculated by the drawing stripe number calculation unit, and divides the drift amount using the numerical value. Particle beam drawing device.   The charged particle beam drawing apparatus according to claim 1, wherein the drift correction amount calculation unit divides the drift amount using the number of drawing stripes calculated by the drawing stripe number calculation unit as it is. A stripe division determination unit that determines whether the estimated drawing time calculated by the estimated drawing time calculation unit is equal to or longer than the correction interval;
A stripe dividing unit that divides the stripe region in which the estimated drawing time is equal to or longer than the correction interval in a short direction when the estimated division time is determined to be equal to or longer than the corrected interval by the stripe division determining unit;
The charged particle beam drawing apparatus according to claim 1, 2 or 3. The drift measurement unit starts measuring the drift amount in response to the drawing interruption in the correction section,
The drawing stripe number calculation unit calculates the number of drawing stripes, which is the number of the stripe regions to be drawn in the remaining correction section from the cancellation of the drawing interruption,
The drift correction amount calculation unit divides the drift amount measured by the drift measurement unit by using the number of drawing stripes calculated by the drawing stripe number calculation unit. 3. The charged particle beam drawing apparatus according to 3 or 4.

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