TWI762714B - Pattern exposure method and pattern exposure device - Google Patents

Abstract

The present invention provides a pattern exposure method and a pattern exposure apparatus, in which a patterned pattern can be formed with good precision by suppressing edge errors on plane corners in exposed image data exposed without a mask. Divide the minimum exposure unit of the light beam on the exposure surface, use the minimum exposure unit to set the specific exposure image data to correct the required beam turn-on area, accumulate the intensity distribution of the light beam according to the minimum exposure unit in the turn-on area, and find The cumulative intensity distribution in the turn-on area is obtained, and the cumulative intensity distribution is compared with the set threshold to obtain a contour on the exposure surface that connects the points where the cumulative intensity distribution is consistent with the threshold as the cumulative intensity profile (AIP), On the outside of the turned-on area, the turn-on unit of the turn-on beam is set according to the minimum exposure unit to correct the exposure image data, so that the difference area surrounded by the outer edge of the turn-on area and the cumulative intensity profile becomes smaller.

Description

Pattern exposure method and pattern exposure device

The present invention relates to a pattern exposure method and a pattern exposure apparatus.

Regarding pattern exposure used in micro-pattern processing such as photolithography, it is known to scan a light beam (including an electron beam) controlled on or off on the surface of a substrate based on exposure image data, and directly on the substrate Unmasked exposure of the delineated pattern. It is used for the ON/OFF control of the light beam in maskless exposure. It is possible to control the light modulation element array such as DMD (Digital Micro-mirror Device), LD or LED array, light source array or gray scale. GLV (Grating light Valve: grating light valve) etc. (for example, refer to the following patent document 1).

[Prior Technology Literature] [Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. 2007-94227

In the above-mentioned conventional pattern exposure (maskless exposure), the minimum unit of exposure that can be controlled is determined according to the scanning pitch of the beam or the array interval such as the light modulation element array, but there is an intensity distribution (for example, a Gaussian distribution) in each beam. , so at the edges of the exposed image data (connected areas and In the boundary of the disconnected area), the accumulated exposure has to gradually become lower, resulting in a dimensional error smaller than the aforementioned minimum unit between the edge line of the exposed image data and the edge line of the pattern obtained after actual development. The situation will become a problem.

In FIG. 1( a ), the minimum unit of exposure is represented by grid lines, and the thick lines represent the edges of the exposed image data. In the example shown in the figure, the inside of the off region drawn with the thick line is the on region of the light beam, and the outside of the off region drawn with the thick line is the off region of the light beam to form the off region. , but the pattern becomes a dot pattern and a hole pattern depending on whether the resist is negative or positive. Thus, whether the inside of the off region is the on region and the outside is the off region, or the inside of the off region is the off region and the outside is the on region depends on the resist used Since it is properly determined according to the desired concavo-convex pattern, there is no problem in essence.

When pattern exposure is performed with these exposure image data, the cumulative intensity distribution of the beams between A1-A2 in Fig. 1(a) becomes like Fig. 1(b). If only the intensity of the beams on the line A1-A2 is accumulated , then it becomes a distribution like P1 to P7, but when the light beams irradiated on all its periphery are accumulated, it becomes an intensity distribution represented by Pf. At this time, if the intensity Et is set as the development threshold of the resist, the edge of the pattern obtained by development becomes S1 divided by the intensity Et, and an error me occurs between the edge S0 in the exposure and development data. As shown in FIG. 1(a), these edge errors me are particularly pronounced at flat corners in the pattern of the exposed image data. In addition, the corners mentioned here naturally include not only the corners of the convex pattern but also the corners of the concave pattern.

The present invention has been made in order to solve these problems. That is, the subject of the present invention is to Suppresses edge errors at the corners of planes in exposed image data exposed to maskless exposure, and forms fine-grained patterns with good precision.

In order to solve these problems, the present invention has the following configuration.

A pattern exposure method, which scans while controlling the on or off of a light beam based on exposure image data, and draws a pattern on an exposure surface. The pattern exposure method is characterized by comprising the following steps: dividing the exposure surface on the The minimum exposure unit of the light beam, the set of the minimum exposure units is used to specify the light beam connection area required for correction in the exposure image data; the intensity distribution of the light beam is accumulated according to the minimum exposure unit in the connection area, and obtained The cumulative intensity distribution in the above-mentioned turn-on area; the above-mentioned cumulative intensity distribution is compared with the set threshold value to obtain a contour formed by connecting the above-mentioned cumulative intensity distribution and the above-mentioned threshold value on the above-mentioned exposure surface as the cumulative intensity profile. ; and set the turn-on unit of the turn-on beam on the outside of the turn-on area according to the minimum exposure unit to correct the exposure image data, so that the difference area surrounded by the outer edge of the turn-on area and the cumulative intensity profile becomes Small.

A pattern exposure device, based on exposure image data, scans the light beam while on or off control, and draws a pattern on the exposure surface, the pattern exposure device is characterized in that it has data for correcting the exposure image data. a correction unit, the data correction unit is provided with the following arithmetic processing unit: dividing the minimum exposure unit of the light beam on the exposure surface, and specifying the connected area of the light beam required for correction in the exposure image data by the set of the minimum exposure unit; The minimum exposure unit in the above-mentioned turn-on area accumulates the intensity distribution of the above-mentioned light beam, and obtains the above-mentioned turn-on area The cumulative intensity distribution of the above-mentioned cumulative intensity distribution is compared with the set threshold value to obtain the contour formed by connecting the above-mentioned cumulative intensity distribution and the above-mentioned threshold value on the above-mentioned exposure surface as the cumulative intensity contour; The outside of the pass-through area is set to the minimum exposure unit to set the pass-on unit of the pass-on beam to correct the exposure image data, so that the difference area surrounded by the outer edge of the pass-through area and the cumulative intensity profile becomes smaller.

1: Pattern exposure device

2: Light irradiation part

3: Scanning section

4: Platform

5: Control Department

6: Data Correction Department

AIP: Cumulative Intensity Profile

D: Differential area

e: Minimum exposure unit

G1, G2, G3: On unit

h: amount of protrusion

L: shortest distance

L _max : maximum value

me: error

S1, S0: Edge

t: point

W: workpiece

1 is an explanatory diagram for explaining the subject of the present invention (FIG. 1(a) shows the minimum unit of exposure and the edge of the exposed image data, FIG. 1(b) shows the light beam between A1-A2 of FIG. 1(a) intensity distribution.).

It is explanatory drawing explaining the pattern exposure method concerning embodiment of this invention.

FIG. 3 is an explanatory diagram for explaining the pattern exposure method according to the embodiment of the present invention.

FIG. 4 is an explanatory diagram for explaining a pattern exposure method according to an embodiment of the present invention.

5 is a flowchart showing a processing algorithm of the pattern exposure method according to the embodiment of the present invention.

It is explanatory drawing which shows the pattern exposure apparatus which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 2 shows a pattern exposure method in which a pattern is drawn on an exposure surface while scanning is performed while on or off control of a light beam is performed based on exposure image data.

The illustrated grid lines divide the minimum exposure unit e of the light beam that can be controlled. The minimum exposure unit e here is appropriately set according to the scanning pitch, the light modulation array, and the array interval of the light source array. Exposure image data can be combined with a minimum exposure unit to specify the beam-on area. In the example shown in the figure, the inner side of the thick line becomes the beam-on area specified according to the exposure image data, and the outer side of the thick line in the illustration becomes the break area of the beam.

As shown in Fig. 2, when the set of minimum exposure units is specific to the ON area of the light beam required for correction in the exposure image data, if the intensity distribution of the light beam is accumulated according to the minimum exposure unit e in the ON area, and By obtaining the cumulative intensity distribution in the ON region, the cumulative intensity distribution shown in Fig. 1(b) can be obtained.

Then, as shown in FIG. 1(b), a specific threshold value Et is set for this cumulative intensity distribution, and the cumulative intensity distribution and the set threshold value Et are compared to obtain a connection between the cumulative intensity distribution and the threshold value on the exposure surface. The contour formed by the consistent points of Et is used as the Accumulated Intensity Profile (AIP). As for the cumulative intensity profile, if the threshold value Et is set as the development threshold value of the resist, the profile of the simulated development pattern is obtained.

In the pattern exposure method of the embodiment of the present invention, the concept of the cumulative intensity profile described above is introduced to correct the exposure image data, so that the cumulative intensity profile is close to the profile of the exposure image data. Specifically, the turn-on unit of the turn-on beam is set according to the minimum exposure unit e outside the turn-on area, so that the outer edge of the turn-on area (the thick line in FIG. 2 ) and the cumulative intensity profile ( The way in which the differential area D enclosed by the single-dot dashed line in FIG. 2 becomes smaller.

As shown in FIG. 2, when the on-unit G1 is set near the corner of the plane in the exposure image data, if the cumulative intensity distribution is obtained in the on-region to which the on-unit G1 is added, and from the cumulative intensity distribution If the cumulative intensity profile is obtained from the intensity distribution, the cumulative intensity profile will be close to the profile of the exposure image data before correction, and the difference area D will be reduced.

Hereinafter, a specific procedure for setting the turn-on unit at the position outside the turn-on area in the exposure image data will be described.

First, the XY coordinates are specified on the exposure surface, and the coordinates (X0, Y0) on the contour of the exposure image data and the coordinates (X1, Y1) on the contour of the accumulated intensity are obtained. Then, the shortest distance L among the distances from one point on the contour of the exposure image data to any point on the contour of the accumulated intensity is obtained. Then, the points on the contour of the exposure image data are arbitrarily moved within the range to be corrected, the shortest distance L to the cumulative intensity contour is obtained at each point, and the exposure image at which the shortest distance L becomes the maximum value _Lmax is specified. Point t on the profile of the data. As shown in FIG. 2, when the exposed image data has a flat corner, the point t on the outline of the exposed image data specified as described above becomes the vertex of the flat corner.

The aforementioned turn-on unit is set in the vicinity of the outer side of the point t on the outline of the exposure image data thus obtained. At this time, the switch-on unit is temporarily set, and the cumulative intensity profile is recalculated only in the area affected by the temporarily-set switch-on unit. After the difference area D becomes smaller, the setting of the temporarily set ON unit is determined. As shown in FIG. 3 , when the turn-on units are sequentially set to G1, G2, and G3, the difference area D is determined to become smaller in the temporary setting of the position of the turn-on unit. When the difference area D does not become smaller, no setting is made and Temporary settings in other locations.

As shown in FIG. 4 , when the turn-on units are sequentially set to G1, G2, and G3, the aforementioned difference area D becomes small, but the cumulative intensity profile may protrude outside the outer edge of the initial turn-on area. When it is desired to actively avoid the protrusion, by calculating the protrusion amount h by which the cumulative intensity profile protrudes outside the outer edge of the initial ON region, the position of the ON unit can be temporarily set to suppress the protrusion amount h. .

FIG. 5 shows an example of a processing algorithm for correcting exposure image data in accordance with the aforementioned steps. In step S1 after the start, the input exposure image data is acquired. In the next step S2, as described above, the cumulative intensity distribution of the ON region of the exposed image data is obtained. In the next step S3, as described above, the threshold value Et is specified, and the cumulative intensity profile of the correction target region is obtained. In the next step S4, as mentioned above, the points on the contour of the exposure image data are arbitrarily moved within the range to be corrected, the shortest distance L to the cumulative intensity contour is obtained at each point, and the shortest distance L is specified as The point t on the contour of the exposed image data of the maximum value _Lmax .

In the next step S5, the aforementioned ON unit is temporarily set in the vicinity of the outer side of the point t on the outline of the exposed image data. Then, in the next step S6, the temporarily set ON unit is added to the ON region of the exposure image data, and the cumulative intensity profile of the correction target region is newly obtained.

Then, in the subsequent step S7, the difference area D obtained from the cumulative intensity profile before the temporary setting of the ON unit is compared with the difference area D obtained from the cumulative intensity profile newly obtained after the temporary setting of the ON unit , so as to judge whether the difference area D obtained from the newly obtained cumulative intensity profile becomes smaller. If it does not become smaller (in the case of "NO"), the temporary setting is canceled, and the process proceeds to step S10, and it is judged whether or not another ON unit is temporarily set.

In step S7, when the difference area D obtained from the newly obtained cumulative intensity profile becomes smaller than the previous difference area D (in the case of "Yes"), the above-mentioned calculation based on the newly obtained cumulative intensity profile is then performed. Judgment of whether the protrusion amount h is within the allowable range (the allowable range here can be set to be zero.). Then, when the protrusion amount h exceeds the allowable range (in the case of NO), the temporary setting is canceled, and the process proceeds to step S10, and it is determined whether or not another ON unit is temporarily set.

Then, in step S8, when the protrusion amount h based on the newly obtained cumulative intensity profile is within the allowable range (if "Yes"), in step S9, the setting of the previously temporarily set ON unit is determined and the process is entered. Going to step S10, it is judged whether or not to temporarily set other on-units.

In step 10, when another on-unit is temporarily set (if "Yes"), the process returns to step S5, a new on-unit is temporarily set in the vicinity of point t, and steps S6 and later are performed in sequence as described above. processing. In step 10, when other on-units are not temporarily set (when "No"), add all the on-units determined so far to the exposure image data of the on-region of the exposure image data correction, and the process ends.

In step 10, in the judgment of whether to temporarily set another ON unit, if the difference area D obtained before is sufficiently small (for example, it becomes less than a certain set value), "NO" in step S7 is repeated several times. If it is continuous, etc., if the ON unit of the difference area D obtained before cannot be found to be reduced, a judgment of “NO” is made.

In addition, in the example of FIG. 5, the example of obtaining _Lmax is shown when the point t is specified, but it is not limited to this, and it is also possible to specify an arbitrary point on the outline of the exposure image data first, and then execute steps S5 to S10 , and thereafter (when step S10 is "NO"), the points are sequentially shifted to perform the same process.

FIG. 6 shows a configuration example of a pattern exposure apparatus that executes the above-described pattern exposure method. The pattern exposure apparatus 1 includes a light irradiation unit 2 that irradiates the light beam Lb on the exposure surface of the workpiece W, a scanning unit 3 that scans a table 4 supporting the workpiece W in a specific direction, and a control unit that controls the light irradiation unit 2 and the scanning unit 3 5. Then, when the exposure image data is input to the control unit 5 , a data correction unit 6 is provided, and the exposure image data corrected by the data correction unit 6 is input to the control unit 5 .

The control unit 5 performs control to draw a pattern on the exposure surface of the workpiece W while scanning on or off the light beam Lb based on the corrected exposure image data. Here, although the scanning part 3 which scans the workpiece|work W is shown in figure, the table 4 may be fixed, and the scanning part which scans the light irradiation part 2 may be provided.

The data correction unit 6 includes an arithmetic processing unit for performing correction of the exposure image data in the above-described pattern exposure method. Correction of the exposure image data is performed before the exposure process, whereby in the maskless exposure, a patterned pattern can be formed with good precision.

AIP: Cumulative Intensity Profile

D: Differential area

e: Minimum exposure unit

G1: Turn-on unit

L: shortest distance

L _max : maximum value

Claims (6)

A pattern exposure method is characterized in that, based on exposure image data, the light beam is controlled on or off and scanned, and a pattern is drawn on the exposure surface, and the method includes the following steps: dividing the light beam on the exposure surface The minimum exposure unit of the above-mentioned minimum exposure unit is used to specify the connection area of the light beam required for correction in the above-mentioned exposure image data; according to the minimum exposure unit in the above-mentioned connection area, the intensity distribution of the above-mentioned light beam is accumulated to obtain The cumulative intensity distribution in the above-mentioned turn-on area; the above-mentioned cumulative intensity distribution is compared with the set threshold value, and the contour formed by connecting the above-mentioned cumulative intensity distribution and the above-mentioned threshold value on the above-mentioned exposure surface is obtained as the cumulative intensity contour; and setting the turn-on unit of the turn-on beam on the outside of the turn-on area according to the minimum exposure unit to correct the exposure image data so that the difference area surrounded by the outer edge of the turn-on area and the cumulative intensity profile becomes smaller . The pattern exposure method as claimed in claim 1, wherein said turn-on unit is set in the vicinity of a corner of a plane in said exposed image data. The pattern exposure method of claim 1, wherein the on-unit is temporarily set, the cumulative intensity profile is newly obtained only in the area affected by the temporarily-set on-unit, and when the difference area becomes smaller, the temporary The setting of the aforementioned turn-on unit of the setting. The pattern exposure method of claim 2, wherein the on-unit is temporarily set, the cumulative intensity profile is newly obtained only in the area affected by the temporarily-set on-unit, and when the difference area becomes smaller, the temporary The setting of the aforementioned turn-on unit of the setting. The pattern exposure method according to any one of claims 1 to 4, wherein the on-unit is set to suppress the protruding amount of the cumulative intensity profile beyond the outer edge of the on-region. A pattern exposure apparatus, characterized in that it controls on or off a light beam based on exposure image data and scans, and draws a pattern on an exposure surface, and is provided with a data correction section for correcting the exposure image data , the data correction unit is provided with the following arithmetic processing unit: dividing the minimum exposure unit of the light beam on the exposure surface, and using the set of the minimum exposure unit to specify the connected area of the light beam required for correction in the exposure image data; Accumulate the intensity distribution of the light beam in the minimum exposure unit in the above-mentioned turn-on area, and obtain the cumulative intensity distribution in the above-mentioned turn-on area; compare the above-mentioned cumulative intensity distribution with the set threshold, and obtain the The contour formed by the points where the aforementioned cumulative intensity distribution is consistent with the aforementioned threshold value is used as the cumulative intensity profile; and on the outside of the aforementioned switching region, the switching unit of the switching beam is set according to the aforementioned minimum exposure unit to correct the aforementioned exposure image data, so that the aforementioned exposure image data is corrected. The differential area enclosed by the outer edge of the aforementioned on-region and the aforementioned cumulative intensity profile becomes smaller.

Images