阅读说明：本技术 曝光装置和曝光方法 (Exposure apparatus and exposure method ) 是由 奥山隆志 于 2020-12-15 设计创作，主要内容包括：本发明提供曝光装置和曝光方法。在曝光装置中,平滑地形成图案倾斜线。在曝光装置(10)中,矢量数据处理电路(40)将轮廓(BD0)的矢量数据变换为向±X方向(轮廓线外侧和/或在轮廓线内侧方向)移位后的轮廓线校正矢量数据(BD+),并通过交替使用原始轮廓线矢量数据(BD0)和轮廓线校正矢量数据(BD+)来执行多重曝光动作。(The invention provides an exposure apparatus and an exposure method. In an exposure apparatus, pattern-inclined lines are smoothly formed. In an exposure apparatus (10), a vector data processing circuit (40) converts vector data of a contour (BD0) into contour correction vector data (BD +) shifted in the + -X direction (the direction outside the contour and/or the direction inside the contour), and performs a multiple exposure operation by alternately using the original contour vector data (BD0) and the contour correction vector data (BD +).)

1. An exposure apparatus, characterized in that the exposure apparatus comprises:

a light modulation element array in which a plurality of light modulation elements are two-dimensionally arranged;

a raster data conversion processing unit that converts vector data, which is pattern data, into raster data; and

a vector data correction processing unit for converting vector data representing a pattern contour line into contour line correction vector data obtained by shifting the pattern contour line in one direction,

multiple exposures are performed based on the contour vector data and the contour correction vector data.

2. The exposure apparatus according to claim 1,

the vector data correction processing unit sequentially converts the contour line vector data into contour line correction vector data at different shift amounts.

3. The exposure apparatus according to claim 2,

the vector data correction processing unit sequentially converts the contour line vector data into contour line correction vector data while periodically changing the shift amount.

4. The exposure apparatus according to claim 3,

the vector data correction processing unit sequentially converts the contour vector data into positive correction vector data shifted to the positive side in one direction and negative correction vector data shifted to the negative side in the one direction,

multiple exposures are performed based on the contour vector data, the positive side correction vector data, and the negative side correction vector data.

5. The exposure apparatus according to claim 4,

the vector data correction processing unit sequentially converts the contour line vector data into a plurality of contour line correction vector data at a shift amount equal to or smaller than the projection area size of the light modulation element.

6. The exposure apparatus according to claim 5,

the shift amount is a shift amount corresponding to the resolution in the main scanning direction.

7. The exposure apparatus according to any one of claims 1 to 6,

the vector data correction processing unit converts the contour vector data into sub-scanning direction correction vector data shifted in a direction corresponding to the sub-scanning direction.

8. A method for exposing a light source to light,

vector data as pattern data is converted into raster data corresponding to a projection area of the light modulation element,

multiple exposures are performed based on the raster data,

characterized in that, in the exposure method,

converting contour line vector data representing a contour line of the pattern into contour line correction vector data in which the contour line of the pattern is moved in one direction,

multiple exposures are performed that combine an exposure based on the contour vector data and an exposure based on the contour correction vector data.

9. The exposure method according to claim 8,

the contour vector data is converted into contour correction vector data by a shift amount along the main scanning direction equal to or smaller than the size of the projection area of the light modulation element.

10. The exposure method according to claim 8 or 9,

the contour vector data is converted into sub-scanning direction correction vector data shifted in a direction corresponding to the sub-scanning direction.

Technical Field

The present invention relates to an exposure apparatus for forming a pattern using an array of light modulation elements, and more particularly to a data conversion process from vector data (vector data) to raster data.

Background

In a maskless exposure apparatus, pattern light is projected onto a substrate by an array of light modulation elements such as a Digital Micromirror Device (DMD) while moving a stage on which the substrate is mounted in a scanning direction. Here, the light modulation elements (micromirrors and the like) arranged in a two-dimensional pattern are controlled so as to project pattern light in accordance with the position of a projection area (exposure area) on the substrate on which the photoresist layer is formed, which is mounted on the stage.

When vector data (design data) such as CAD/CAM data is input to the exposure apparatus, the vector data is converted into raster data that can be applied to the light modulator array. The raster data is bit (bit) map data indicating exposure data of each micromirror, and the projection image of the micromirror becomes a rectangle. Therefore, when the pattern includes an oblique line, a stepped pattern having a step is formed.

In order to reduce this, a method has been proposed in which exposure data indicating oblique lines is provided with a plurality of levels of density for each exposure region to smooth the oblique lines (see patent document 1). Here, the maximum density is given to an exposure region near the center of the pattern, and the intermediate density is given to an exposure region including a step portion such as an oblique line which becomes a pattern boundary. Further, by setting the light intensity for the exposure region of the intermediate concentration to half of the light intensity for the exposure region of the maximum concentration, more levels of inclined lines are formed, and the resolution is improved.

[ Prior art documents ]

[ patent document ]

[ patent document 1] Japanese patent application laid-open No. 2011-

Disclosure of Invention

[ problems to be solved by the invention ]

The processing of giving exposure data a plurality of levels of density for each exposure area increases the data amount compared to the conventional one, and requires a large-scale data processing circuit. In addition, since the conversion processing (correction processing) of raster data is additionally performed, the processing time increases and the throughput decreases.

Therefore, in the exposure apparatus, it is necessary to smoothly form the pattern tilt line without complicating the data processing.

[ means for solving the problems ]

An exposure apparatus of the present invention includes: a light modulation element array in which a plurality of light modulation elements are two-dimensionally arranged; a raster data conversion processing unit that converts vector data, which is pattern data, into raster data; and a vector data correction processing unit that converts vector data indicating the pattern contour line into correction vector data (hereinafter, referred to as contour line correction vector data) in which the pattern contour line is shifted in one direction.

The direction in which the pattern contour line is shifted can be set to various directions, and the raster data conversion processing unit can shift the contour size, the pattern size, and the like of the pattern contour line in the direction of enlargement (outward) or in the opposite direction (inward). When the main scanning direction and the sub-scanning direction are defined on the substrate, the raster data conversion processing unit can move the pattern profile line in one direction of the two-dimensional coordinate system. Here, "shift in one direction" includes, for example, positive and negative directions in the case of shift in the sub-scanning direction.

In the exposure apparatus of the present invention, multiple exposure is performed based on data of a pattern contour line that is not subjected to shift correction (hereinafter, referred to as contour line vector data) and contour line correction vector data after shift correction. For example, the exposure apparatus may include an exposure control unit that performs multiple exposure operations at a predetermined pitch. Since the edge portion corresponding to the threshold value of the photosensitive material of the substrate based on the cumulative exposure amount after the multiple exposure shifts by the data amount, the resolution can be improved.

The vector data correction processing unit can sequentially convert the contour line vector data into a plurality of contour line correction vector data at a shift amount equal to or smaller than the projection area size of the light modulation element. For example, by specifying the shift amount as a shift amount corresponding to the resolution in the main scanning direction (including apparent resolution), the resolution in the sub scanning direction can be increased to the same resolution as the main scanning direction by the shift correction of the vector data.

The vector data correction processing unit can sequentially convert the contour line vector data into contour line correction vector data at different shift amounts. For example, the vector data correction processing unit can sequentially convert the contour line vector data into the contour line correction vector data while periodically changing the shift amount.

The vector data correction processing unit can convert the contour vector data into positive-side correction vector data shifted in one direction (referred to as a positive side herein) or negative-side correction vector data shifted in the opposite direction (referred to as a negative side herein), and can convert the contour vector data while sequentially shifting the contour vector data to the positive side and the negative side. The exposure device performs multiple exposures based on the contour vector data, the positive-side correction vector data, and the negative-side correction vector data.

In an exposure method according to another aspect of the present invention, vector data as pattern data is converted into raster data corresponding to a projection region of a light modulator, and multiple exposure is performed based on the raster data, wherein contour line vector data indicating a pattern contour line is converted into contour line correction vector data in which the pattern contour line is moved in one direction, and multiple exposure is performed in which exposure based on the contour line vector data and exposure based on the contour line correction vector data are combined. The contour vector data is converted into contour correction vector data by a shift amount along the main scanning direction equal to or smaller than the size of the projection area of the light modulation element, or converted into sub-scanning direction correction vector data shifted in a direction corresponding to the sub-scanning direction.

[ Effect of the invention ]

According to the present invention, a pattern slant line can be smoothly formed in an exposure apparatus.

Drawings

Fig. 1 is a block diagram of an exposure apparatus according to the present embodiment.

Fig. 2 is a diagram showing a correction process of vector data for a part of a pattern contour line.

Fig. 3 is a diagram showing the exposure amount along the sub-scanning direction Y.

Fig. 4 is a view showing the position of the Y-direction line in fig. 3.

Fig. 5 is a diagram showing a pattern obtained through a subsequent process such as exposure and development.

Fig. 6 is a diagram showing a modification of the correction process of the vector data.

Description of the reference symbols

10 Exposure device

22 DMD (light modulation element array)

30 controller

40 vector data processing circuit (vector data correction processing unit)

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Fig. 1 is a block diagram of an exposure apparatus according to the present embodiment.

The exposure apparatus 10 is a maskless exposure apparatus that forms a pattern by irradiating light to a substrate (exposure target) W to which a photosensitive material such as a photoresist is applied or bonded, and a stage 12 on which the substrate W is mounted is provided movably in a main scanning direction. The stage drive mechanism 15 moves the stage 12 in the main scanning direction X and the sub-scanning direction Y.

The exposure apparatus 10 includes a DMD22, an illumination optical system 23, and a projection optical system 25, and is provided with a plurality of exposure heads 18 (only 1 exposure head is shown in fig. 1) for projecting pattern light. The light source 20 is constituted by, for example, a discharge lamp, and is driven by a light source driving unit 21.

The CAD/CAM data as pattern data is input to the exposure apparatus 10 as vector data. The controller 30 of the exposure apparatus 10 converts the vector data represented by the rendering coordinate system into an exposure coordinate system specific to the exposure apparatus 10, and transmits the converted vector data to a vector data processing circuit (vector data correction processing unit). The exposure coordinate system is defined along the main scanning direction X and the sub-scanning direction Y of the exposure apparatus.

The vector data processing circuit 40 extracts vector data (of an exposure coordinate system) corresponding to a predetermined exposure range, and sends the vector data to the raster data conversion circuit (raster data conversion processing unit) 26. Further, as described below, data correction processing is performed on a part of the vector data.

The grid data conversion circuit 26 converts the vector data into grid data, stores the grid data in a cell (cell) size (size) memory (not shown) corresponding to a projection area (unit exposure area, also referred to as a cell) of 1 micromirror, and converts the grid data into bitmap data in units of an area (hereinafter referred to as a sub-cell) having a cell size of not more than 1. In accordance with a control signal from the controller 30, the bitmap data at a predetermined address is read from the raster data conversion circuit 26 and sent to the DMD drive circuit 24 as exposure data.

The DMD22 is an array of light modulation elements in which tiny micromirrors are two-dimensionally arranged, and each micromirror selectively switches the direction of light reflection by changing its posture. By controlling the postures of the respective mirrors by the DMD drive circuit 24, light corresponding to the pattern is projected (imaged) onto the surface of the substrate W via the projection optical system 25.

The stage drive mechanism 15 moves the stage 12 in accordance with a control signal from the controller 30. The controller (exposure control unit) 30 controls the operation of the exposure apparatus 10, and outputs control signals to the stage drive mechanism 15, the DMD drive circuit 24, the vector data processing circuit 40, and the like, based on stage position information sent from a position detection unit (not shown). During the exposure operation, the stage 12 moves at a fixed speed, and the entire projection area (hereinafter referred to as exposure area) of the DMD22 moves relative to the substrate W in the main scanning direction X as the substrate W moves. Alternatively, the stage 12 may be moved intermittently instead of continuously.

The controller 30 controls the vector data processing circuit 40, the DMD drive circuit 24, and the like to perform multiple exposures, that is, overlap exposures in which the next exposure is performed in sequence at a position overlapping a part of the preceding exposure area. The exposure operation is performed at predetermined pitch intervals, and each micromirror of the DMD22 is modulated according to the relative position of the exposure area (stage position), thereby sequentially projecting the light of the pattern to be drawn at the position of the exposure area.

The projection area of each exposure head 18, that is, the entire projection area (hereinafter referred to as exposure area) EA of the DMD22 is an area inclined by a slight angle with respect to the main scanning direction X, and moves relatively in the main scanning direction X in an inclined state. Thereby, the exposure point (exposure hit center position) is gradually shifted in the sub-scanning direction Y.

The pitch interval of the multiple exposure operation is set to an interval other than an integral multiple of the unit exposure field, and the amount of movement in the sub-scanning direction Y is smaller than that of the unit exposure field. Therefore, a plurality of exposure points are distributed in both the main scanning direction X and the sub-scanning direction Y in the unit exposure field, and a pattern having a resolution equal to or lower than the resolution of the unit exposure field can be formed.

Further, in the present embodiment, the apparent resolution is improved by adjusting the pitch interval of the multiple exposure operation in the main scanning direction X, and the apparent resolution is improved by the correction processing of the vector data in the sub-scanning direction Y. This will be described in detail below.

Fig. 2 is a diagram showing a correction process of vector data for a part of a pattern contour line. In fig. 2, this is represented by an exposure coordinate system (X-Y).

The vector data is defined by two-dimensional coordinates of a start point and an end point of a contour line of the pattern data (graphics data), and is defined by a unit of expression of the drawing data (for example, 1 μm). Here, vector data indicating a part of the contour line BD0 of the pattern is represented by position coordinates of points P1 to P4.

As described above, the raster data conversion circuit 26 converts the vector data of the contour line BD0 into raster data RD which is bit map data in units of sub cells. The grid data RD0 is represented as cells to represent micromirrorsSize ofThe bit map data in which sub-cells each formed by dividing C (unit exposure field) into n parts (n is an integer, where n is 16) in the main scanning direction X and the sub-scanning direction Y are arranged as a unit generates a step-like step in the contour portion T. With respect to the main scanning direction X, resolution in units of 1/2 sub-cells is realized by adjusting the pitch interval of the exposure operation.

In the multiple exposure operation, exposure is repeated based on the vector data of the pattern to be formed on the substrate W, and the shift-corrected vector data and the original vector data are sequentially sent to the grid data conversion circuit 26. That is, exposure is performed alternately using exposure data generated from the vector data after the shift correction and exposure data generated from the vector data without the shift in each exposure step of the multiple exposure operation.

The vector data processing circuit 40 first extracts the vector data of the contour line BD0 without correction (step 1). In the next exposure operation, after the extraction processing of the vector data, the vector data of the contour line BD0 is subjected to coordinate conversion processing to be converted (corrected) into vector data of a contour line BD + which has been moved by a predetermined movement amount Δ S in the sub-scanning direction Y (contour line correction vector data).

If the sub-unit size is denoted by SC, the shift amount Δ S corresponds to a distance of 1/2 × SC along the sub-scanning direction Y. As shown in fig. 2, the contour line BD + is a line outside the contour line BD0, i.e., a line shifted in parallel from the pattern boundary line toward the pattern outside, and the distance D between the contour line BD0 and the contour line BD + is smaller than the cell size C and the sub-cell size SC. The vector data of the contour line BD + is represented by position coordinates P1 'to P4'. Since the vector data of the contour line BD + is converted into the raster data RD +, the staircase contour line T + of the raster data RD + is also shifted in the sub-scanning direction Y by 1/2 × SC as a whole (step 2).

In the multiple exposure operation, the exposure operation is performed for a predetermined number of exposures (for example, several tens of exposures) in the same exposure region, and during this period, step 1 and step 2 are repeated. This processing is performed not only on the vector data of the contour line BD0 shown in fig. 2, but also on all the vector data. However, this processing may be performed only on vector data representing inclined lines/curves that are not parallel to the X direction and the Y direction with respect to the exposure coordinate system X-Y.

Fig. 3 is a diagram showing the exposure amount along the sub-scanning direction Y. Fig. 4 is a view showing the position of the Y-direction line in fig. 3. However, in fig. 4, the sub-cell size SC is defined as a 4-divided portion of the cell size C for convenience of explanation.

Fig. 3 shows the exposure amount along the line a-B of fig. 4 (particularly, the exposure amount between the position (1) and the position (2) in the Y direction). The photosensitive material formed on the substrate W is exposed to light with an exposure amount of a threshold value or more, and a region of the threshold value or more appears as a pattern. As described above, the exposure area of the DMD22 is inclined at a slight angle with respect to the main scanning direction X, and the exposure points are shifted in the sub-scanning direction Y at pitch intervals of not more than the cell size between the multiple exposure operations. Therefore, when exposure is performed based on the vector data of the contour line BD0, the exposure amount M0 thereof is represented as a line shown in fig. 3, and decreases toward the outside of the pattern with a fixed slope.

On the other hand, when exposure is performed based on the vector data of the contour line BD +, the exposure amount M + is similarly a line that decreases outward from the pattern with a constant slope, and is shifted by 1/2 × SC in the sub-scanning direction Y with respect to the exposure amount M0. As a result, the exposure amount M, which is the sum of the exposure amount M0 and the exposure amount M +, becomes a line whose slope is fixed in the vicinity of the threshold, and whose slope is substantially equal to the slopes of the exposure amount M0 and the exposure amount M +.

As a result, the contour line (edge) EL along the X direction is formed not at the end edge position of the subcell but inside the subcell, realizing pattern formation of 1/2 × SC resolution. The exposure pitch interval along the sub-scanning direction Y is constant, and the apparent resolution in the sub-scanning direction Y is 1/2 × SC, which is equal to the apparent resolution in the main scanning direction X.

Fig. 5 is a diagram showing a pattern obtained through a subsequent process such as exposure and development. As shown in fig. 5, the inclined line PL of the pattern P is formed at a resolution equal to or less than the sub cell size SC, and becomes a line in which steps are suppressed.

As described above, according to the present embodiment, in the exposure apparatus 10, the vector data processing circuit 40 converts the vector data of the contour line BD0 into the contour line correction vector data BD + shifted in the ± Y direction (the direction outside the contour line and/or the direction inside the contour line), generates exposure data by alternately using the original contour line vector data BD0 and the contour line correction vector data BD +, and executes a multiple exposure operation.

Generally, the smoothness of the formed pattern is proportional to the resolution of the bitmap data in units of sub-units, i.e., the size of the cell size memory. However, by the correction of the vector data described above, a smooth pattern can be formed while suppressing the scale of the cell size memory. That is, the inclination line of the pattern can be smoothed by a simple arithmetic processing without complicating and enlarging the circuit scale. In addition, the number of exposures of the vector data of the original contour line is made equal to or less than half the number of multiple exposures, whereby the edge portion of the pattern can be made clearer.

In the present embodiment, the multiple exposure operation is performed using the vector data of the contour line as one shift amount and alternately using the vector data of the uncorrected contour line, but a plurality of pieces of shift correction vector data may be generated using different shift amounts and may be sequentially used to perform the multiple exposure operation. The vector data of the contour lines may be moved in the negative (negative) direction (-Y) without being moved in the positive (+ Y) direction of the sub-scanning direction Y. Further, the vector data of one contour line may be shift-corrected in both the positive and negative directions.

Fig. 6 is a diagram showing a modification of the vector data correction processing performed using a plurality of shift amounts.

Here, vector data of the contour line BD0 is generated, which is the vector data of the contour line BD + shifted in the + Y direction by 1/2 × SC (═ Δ S), the vector data of the contour line BD2+ shifted in the + Y direction by SC (═ Δ 2S), and the vector data of the contour line BD-shifted in the-Y direction by 1/2 × SC (═ Δ S). Then, the vector data of the contour lines BD0, BD +, BD2+, and BD-are repeatedly used in this order to perform the multiple exposure operation. This enables a smooth pattern corresponding to the cell division number 1/64 to be formed.

Further, the vector data of the contour line BD + shifted in the + Y direction by 1/2 × SC (═ Δ S) and the vector data of the contour line BD-shifted in the-Y direction by 1/2 × SC (═ Δ S) may be generated for the vector data of the contour line BD0, and the multiple exposure operation may be performed while sequentially repeating the use of the vector data of the 3 contour lines. According to this multiple exposure operation, the vector data of the original contour without correction is used for the number of exposures equal to or less than half of the number of multiple exposures.

In the case of using a plurality of shift amounts, a reference table indicating the shift amounts may be stored in a memory or the like, and the controller 30 may control the vector data processing circuit 40 using the reference table to sequentially convert the vector data of the contour line. The conversion (correction) processing of the vector data may be performed by another circuit such as the controller 30. The sub-cell size SC may be divided into the cell size C by a division number other than 16 division according to the size of the cell size memory.

In the present embodiment, the correction process of shifting the vector data of the contour line in the sub-scanning direction Y is performed, but the present invention is not limited to this, and the vector data of the contour line may be shifted in a predetermined one direction within a range in which the vector data can be expressed. The correction processing of the vector data may be performed by an arithmetic processing unit or the like other than the exposure device.