JP2010026465A - Pattern drawing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scanning type pattern drawing device capable of carrying out exposure drawing with high accuracy and a large throughput even when the sensitivity of a photoresist is varied in many ways. <P>SOLUTION: The device is equipped with: a stage; a light modulating unit modulating the light of a light source; an irradiation unit irradiating a photosensitive material layer with the modulated light; a luminous energy adjusting unit adjusting the luminous energy of the light incident on the light modulating unit; a scanning mechanism for scanning the irradiating unit in a scanning direction relative to the stage; a control unit controlling the luminous energy adjusting unit and the scanning mechanism; a first memory unit matching and storing a plurality of exposure light quantities to be selected in accordance with the photosensitivity of a photosensitive material layer with scanning velocities suitable to the respective exposure quantities; and a second memory unit storing values of control parameters of the control unit suitable to the respective scanning velocities. The control unit selects a scanning velocity matching with the input exposure light quantity from the scanning velocities stored in the first memory unit and selects a value of control parameter suitable to the selected scanning velocity from the values of control parameters stored in the second memory unit. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pattern drawing apparatus, and more particularly to a scanning pattern drawing apparatus that can perform high-precision exposure drawing with a large throughput even when the sensitivity of a photoresist is changed.

  Conventionally, as an example of a drawing apparatus, a light beam such as a laser beam using a light modulation element such as GLV (Grating Light Valve) (registered trademark of Silicon Light Machines (Sunnyvale, Calif.)). Has been proposed (see Patent Document 1) that modulates the light into beam light according to image data and exposes the photoresist with the modulated light.

  This type of drawing apparatus (hereinafter referred to as a scanning type drawing apparatus) irradiates the photoresist with modulated light while reciprocating the stage on which the substrate coated with the photoresist is placed, thereby providing a circuit or the like to the photoresist. This pattern can be exposed and drawn. The scanning drawing apparatus generates a drawing pattern electronically by GLV, and does not require a mask that has been used in an exposure apparatus before that. Therefore, the mask manufacturing process becomes unnecessary. Thereby, the manufacturing process of a liquid crystal display and a semiconductor substrate can be shortened, and the manufacturing cost of a mask becomes unnecessary.

  In a maskless scanning drawing apparatus, in order to improve drawing throughput, a plurality of exposure heads including light modulation elements are generally arranged in parallel to form a multi-head.

By the way, in the manufacture of a substrate such as a liquid crystal display, the type and thickness of the photoresist are changed for each product in order to improve the yield of each process and optimize various conditions. Along with the change, the amount of light necessary for exposure (unit: mJ / cm ² ), that is, sensitivity changes. The amount of light given to the unit area of the photoresist is determined by the amount of light irradiated from the exposure head and the speed of the stage. On the other hand, the maximum output of the exposure head is set for each drawing apparatus. Therefore, by changing the speed of the stage, it is possible to change the amount of light applied to the unit area of the photoresist within a range not exceeding the maximum output of the exposure head, and to cope with changes in the type of photoresist. As the stage speed increases, the exposure throughput improves.

  In order to deal with various products, it is conceivable to perform exposure by changing the scanning speed of the stage steplessly. However, in a multi-head scanning drawing apparatus, when the stage speed is changed steplessly, it is difficult to perform stage control and drawing timing control with high accuracy. The reason will be described below.

First, an example in which stage control becomes difficult will be described.
In a scanning type drawing apparatus, when the stage reciprocates in the main scanning direction and the forward path and the backward path are switched, the stage is moved in the sub scanning direction (perpendicular to the main scanning direction) by the width that one exposure head exposes in one forward scanning. Direction). Thereby, striped exposure is performed.

  However, when the stage moves in the main scanning direction, a slight stage rotation (yawing) occurs, and the characteristics of this yawing are different for each stripe. For this reason, the belt-like scan rows constituting the stripe are not parallel to each other, and a gap may be formed between the scan rows.

  In order to eliminate such a problem, it is conceivable to correct the direction of the stage (yawing correction) by rotating the stage during the main scanning movement. Specifically, a correction rotation angle for rotating the stage in the direction opposite to the rotation (yawing) that occurs in the stage may be set for each scan row, and correction may be performed based on the correction rotation angle.

  However, the correction rotation angle to be set cannot be expressed as a function of the stage speed. Therefore, originally, it is necessary to set a correction rotation angle for each scanning row and set the correction rotation angle for each speed. Therefore, when the stage speed is changed steplessly, it is difficult to set the correction rotation angle.

Next, an example in which timing control becomes difficult will be described.
As shown in FIG. 9A, the exposure heads 13 are ideally aligned on the same straight line. However, it is difficult to align the exposure heads precisely on the same straight line. Actually, as shown in FIG. 9B, the positions of the exposure heads are slightly shifted in the scanning direction. If exposure by the exposure heads 13 is started simultaneously in this state, the position of the scan row is shifted in the scanning direction between the exposure heads 13 as shown in FIG.

  In order to solve such a problem, it is conceivable to correct the exposure start timing of each exposure head. Specifically, the exposure start timing may be corrected according to the positional deviation amount of the exposure head.

  However, depending on the characteristics of the circuit that controls the exposure timing of the exposure head, if the stage speed changes, the exposure may start slightly later than the corrected exposure start timing. In such a case, precise correction cannot be performed unless the correction timing is set in consideration of the characteristics of the control circuit. The characteristics of the control circuit cannot be expressed as a function of stage speed. Therefore, when the stage speed is changed steplessly, it is difficult to set the correction timing.

Therefore, in the conventional scanning exposure drawing apparatus, when the sensitivity of the photoresist is variously changed, it is difficult to perform exposure at an optimum speed.
JP 2003-59804 A

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a scanning pattern drawing apparatus capable of performing high-precision exposure drawing with a large throughput even when the sensitivity of the photoresist is variously changed. And

A pattern drawing apparatus according to the present invention includes:
A pattern drawing apparatus that exposes and draws a pattern on a substrate by irradiating light to the photosensitive material layer of the photosensitive substrate,
A stage on which a photosensitive substrate is installed;
A light source;
A light modulator that modulates the light of the light source into light of a pattern to be drawn;
An irradiation unit that irradiates the photosensitive material layer with modulated light while moving relative to the substrate in the scanning direction;
A light amount adjustment unit for adjusting the amount of light incident on the light modulation unit;
A scanning mechanism that scans the irradiation unit relative to the stage along the scanning direction;
A control unit for controlling the light amount adjusting unit and the scanning mechanism;
A first storage unit that stores a plurality of exposure amounts selected according to the photosensitivity of the photosensitive material layer and a scanning speed suitable for each of the exposure amounts in association with each other;
A second storage unit that stores values of control parameters of the control unit suitable for the scanning speeds;
An input unit for inputting an exposure amount irradiated by the irradiation unit;
The control unit selects a scanning speed corresponding to the exposure amount input by the input unit from the scanning speeds stored in the first storage unit, and a control parameter value suitable for the selected scanning speed. Is selected from the control parameter values stored in the second storage unit, and the scanning mechanism and the light amount adjusting unit are controlled based on the selected scanning speed and control parameter value.

According to this invention, a 1st memory | storage part matches and memorize | stores the some exposure amount selected according to the photosensitivity of the photosensitive material layer, and the scanning speed suitable for each said exposure amount, respectively. Therefore, even if the sensitivity of the photosensitive material layer is variously changed, it is possible to set a scanning speed suitable for each sensitivity.
In addition, the control unit selects a scan speed suitable for the light sensitivity input from the input unit from the scan speeds stored in the first storage unit, and sets a control parameter value suitable for the selected scan speed. The control parameter value stored in the second storage unit is selected. The control unit controls the scanning mechanism and the light amount adjusting unit based on the selected scanning speed and control parameter value. Therefore, even if the sensitivity of the photosensitive material layer is variously changed, control based on the scanning speed and the value of the control parameter suitable for each sensitivity is performed. Therefore, even if the sensitivity of the photosensitive material layer is variously changed, it is possible to provide a scanning pattern drawing apparatus that performs high-precision exposure drawing with a large throughput.

In the present invention,
The light amount adjusting unit is
It is preferable that the attenuator is provided between the light source and the light modulation unit and adjusts the amount of light by reflecting a part of the light of the input light source and outputting the light that is not reflected.

  According to this configuration, the amount of light can be reliably adjusted by the attenuator.

In the present invention,
Each scanning speed stored in the first storage unit is preferably a speed corresponding to the light amount when the light amount adjustment unit does not adjust the light amount.

  According to this structure, each scanning speed memorize | stored in the 1st memory | storage part is a speed corresponding to the light quantity when not adjusting light quantity by a light quantity adjustment part. The stage speed can be increased as the amount of light increases. Therefore, the stage speed is maximized when the amount of light is not adjusted. Therefore, the drawing throughput can be increased more reliably.

In the present invention,
It is preferable that a plurality of exposure heads including the light modulation unit, the irradiation unit, and the light amount adjustment unit are arranged in parallel.

  According to this configuration, a multi-head exposure apparatus is provided by arranging a plurality of exposure heads in parallel. Therefore, the drawing throughput can be further increased.

In the present invention,
The light amount adjusting unit is
The amount of light from the light source may be adjusted.

  According to this configuration, since the light amount of the light source is adjusted, energy loss can be reduced as compared with the case where the light emitted from the light source is adjusted by an attenuator or the like.

  According to the present invention, it is possible to provide a scanning pattern writing apparatus capable of performing high-accuracy exposure drawing with a large throughput even when the sensitivity of a photoresist is variously changed.

(First embodiment)
A pattern drawing apparatus according to a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram illustrating a pattern drawing apparatus according to the first embodiment. FIG. 2 is a diagram illustrating drawing pixels. FIG. 3 is a view showing a state in which exposure scanning is performed by each exposure head. FIG. 4 is a diagram showing a state in which scanning exposure is performed by each exposure head. FIG. 5 is a diagram illustrating the light sensitivity and the scanning speed stored in the first storage unit.

  As shown in FIG. 1, the pattern drawing apparatus 1 according to the first embodiment irradiates a photosensitive material layer (not shown) of a photosensitive substrate 2 with light, thereby providing a circuit or the like to the photosensitive substrate 2. This is an apparatus for exposing and drawing the pattern.

  The pattern drawing apparatus 1 includes a stage 3, a light source 4, an illumination optical system 14, a plurality of exposure heads 13, a scanning mechanism 8, a control unit 9, a first storage unit 10, and a second storage unit 11. The input unit 12 is provided. The plurality of exposure heads 13 are positioned above the stage 3 and arranged in parallel along the sub-scanning direction X that is perpendicular to the main scanning direction Y of the stage 3.

  The photosensitive substrate 2 is installed on the upper surface of the stage 3.

  The light source 4 includes a laser driving unit and a laser diode. The laser diode outputs beam light (laser light) by being driven by a laser driving unit. In FIG. 1, the flow of the beam light from the light source 4 to the irradiation unit 6 is indicated by a one-dot chain line.

  The illumination optical system 14 distributes the beam light of the light source 4 to each exposure head 13 by the same amount of light. In the example shown in FIG. 1, the beam light separated by the illumination optical system 14 is incident on the exposure head 13 via the light amount adjusting unit 7.

  The light amount adjustment unit 7 adjusts the amount of light incident on the light modulation unit 5 of the exposure head 13. The configuration of the light amount adjusting unit 7 is not particularly limited. For example, as shown in FIG. 1, an attenuator provided between the illumination optical system 14 and the light modulating unit 5 can be used. The attenuator adjusts the amount of emitted light to 0 to 100% of the amount of incident light by reflecting a portion of the light from the input light source 4 and outputting the light that has not been reflected.

  The exposure head 13 includes a light modulation unit 5 and an irradiation unit 6.

The light modulation unit 5 is composed of, for example, a diffraction grating type light modulation element. As a diffraction grating type light modulation element, for example, GLV (Grating Light Valve) (registered trademark of Silicon Light Machines (Sunnyvale, Calif.)) Is known. The GLV includes a plurality of diffraction gratings that can individually control the diffraction angles of light that is linearly arranged and enters. By controlling the shape of each diffraction grating, the diffraction angle of light in each diffraction grating is controlled, and thereby light modulation is performed. As shown in FIG. 2, the exposure head 13 is formed with a plurality of beam emission regions 20 (for example, 2000 regions arranged in a row) 20 arranged in a row corresponding to each diffraction grating. . One beam light emission region 20 functions as one drawing pixel. As shown in FIGS. 2, 3, and 4, when scanning is performed in a state where the beam light is emitted from the beam light emission region 20, a belt-like scan row 21 is formed. That is, the scanning row 21 area is scanned and exposed. By this scanning exposure, a strip-shaped exposure pattern (not shown) is drawn on the photosensitive material layer. An arrow shown in each scanning row 21 indicates the scanning direction of the exposure head 13. As shown in FIGS. 3 and 4, the exposure heads 13 are spaced apart from each other. Each exposure head 13 performs scanning exposure in opposite directions on the forward path and the backward path.
The light beam distributed by the illumination optical system 14 is light-modulated by the light modulator 5, and light light corresponding to the pattern to be drawn is generated by this light modulation.

  The irradiation unit 6 irradiates the photosensitive material layer with the modulated beam light while moving relative to the photosensitive substrate 2 in the scanning direction. The irradiation unit 6 is composed of a lens optical system including an objective lens. The vertical focus position of the light beam modulated by the light modulation unit 5 is adjusted by the vertical movement of the objective lens. The light beam whose focal position is adjusted is irradiated onto the photosensitive material.

  When the exposure head 13 exposes the photosensitive material layer of the photosensitive substrate 2, the exposure head 13 controls the diffraction angle in each diffraction grating of the GLV based on the control signal generated by the drawing pattern generation unit 15 based on the drawing image data. To modulate the light beam. Whether or not the light beam is emitted from the light beam emission region 20 is controlled by modulation. The exposure head 13 performs scanning exposure of the photosensitive substrate 2 with a plurality of light beams whose emission is controlled.

The scanning mechanism 8 scans the irradiation unit 6 along the scanning direction relative to the stage 3. The scanning mechanism 8 includes a main scanning mechanism, a sub-scanning mechanism, and a rotating mechanism (all not shown).
The main scanning mechanism reciprocates the exposure head 13 along the main scanning direction Y relative to the stage 3. For example, the main scanning mechanism moves the stage 3.

  The sub-scanning mechanism causes the exposure head 13 to scan in the sub-scanning direction X that is orthogonal to the main scanning direction Y relative to the stage 3. The sub-scanning mechanism moves the stage 3, for example.

  The input unit 12 inputs an exposure amount given to the photosensitive material layer. The input unit 12 is connected to the device control unit 16 of the control unit 9. The exposure amount is energy per unit area given to the photosensitive substrate 2 to be exposed, and is input by the user.

As illustrated in FIG. 5, the first storage unit 10 includes a plurality of exposure amounts (mJ / cm ² ) selected according to the photosensitivity of the photosensitive material layer, and scanning speeds suitable for each exposure amount. (Mm / sec) is associated and stored as the lookup table 22. Each scanning speed stored in the first storage unit 10 is a speed corresponding to the light amount when the light amount adjustment unit 7 does not adjust the light amount. The first storage unit 10 is connected to the device control unit 16 of the control unit 9.

As shown in FIG. 5, the stage speed is set to one value for each exposure amount.
The look-up table 22 shown in FIG. 5 is a look-up in an exposure apparatus having an ability to perform exposure drawing at a stage speed of 50 (mm / sec) on a photosensitive material layer having a photosensitivity of 240 (mJ / cm ² ). It is a table. The light amount adjusting unit 7 can adjust the light amount from the illumination optical system 14 to 0 to 100%. Therefore, it is possible to draw with a light amount of 0 to 240 (mJ / cm ² ) at a stage speed of 50 (mm / sec). When the stage speed is doubled to 100 (mm / sec), the amount of light is half that of 50 (mm / sec), that is, drawing can be performed with a light amount of 0 to 120 (mJ / cm ² ). Similarly, every time the scanning speed is doubled to 200 (mm / sec) or 400 (mm / sec), the light amount is halved. In this way, the lookup table 22 is configured.

That is, when the exposure amount to be input is greater than 0 and 30 or less (mJ / cm ² ), the stage scanning speed is set to 400 (mm / sec). When the exposure amount to be input is greater than 30 and 60 or less (mJ / cm ² ), the stage scanning speed is set to 200 (mm / sec). When the exposure dose to be input is greater than 60 and 120 or less (mJ / cm ² ), the stage scanning speed is set to 100 (mm / sec). When the exposure amount to be input is greater than 120 and 240 or less (mJ / cm ² ), the stage scanning speed is set to 50 (mm / sec).

In this example, for example, 20 in order to pattern drawn on the photosensitive material layer having a light sensitivity (mJ / cm ^2), when the user inputs 20 (mJ / cm ²⁾ for the input unit 12 as an exposure amount, device A stage speed of 400 (mm / sec) is selected by the control unit 16. 30 in order to pattern drawn on the photosensitive material layer having a light sensitivity (mJ / cm ^2), even if the user inputs 30 (mJ / cm ²⁾ for the input unit 12 as an exposure amount, the device control unit 16 400 A stage speed of (mm / sec) is selected.

Further, in order to pattern drawn on the photosensitive material layer having a light sensitivity of 40 (mJ / cm ^2), when the user inputs 40 (mJ / cm ²⁾ for the input unit 12 as an exposure amount, the device control unit 16 A stage speed of 200 (mm / sec) is selected. 60 in order to pattern drawn on the photosensitive material layer having a light sensitivity (mJ / cm ^2), even if the user inputs 60 (mJ / cm ²⁾ for the input unit 12 as an exposure amount, the apparatus control unit 16 200 A stage speed of (mm / sec) is selected.

  The second storage unit 11 stores control parameter values of the control unit 9 that are suitable for each scanning speed. The second storage unit 11 is connected to the device control unit 16 of the control unit 9. The type of the control parameter is not particularly limited, and examples thereof include a correction rotation angle of the stage 3, an exposure start timing of the exposure head 13, and a light amount aperture ratio of the light amount adjusting unit 7.

  The control unit 9 includes an apparatus control unit 16, a drawing pattern generation unit 15, a light modulation unit control circuit 17, a stage drive system control circuit 18, and a light amount adjustment unit control circuit 19.

  The control unit 9 controls the scanning mechanism 8, the light amount adjustment unit 7, and the light modulation unit 5 as a whole.

  The apparatus control unit 16 outputs necessary data and control signals to the drawing pattern generation unit 15, the light modulation unit control circuit 17, the stage drive system control circuit 18, and the light amount adjustment unit control circuit 19.

  The apparatus control unit 16 selects a scanning speed corresponding to the exposure amount input from the input unit 12 by the user's light sensitivity input operation from the scanning speeds stored in the first storage unit 10. The apparatus control unit 16 selects a control parameter value suitable for the selected scanning speed from the control parameter values stored in the second storage unit 11. The apparatus control unit 16 outputs the selected scanning speed and control parameter value to the stage drive system control circuit 18. The stage drive system control circuit 18 controls the scanning mechanism 8 based on the input scanning speed and control parameter values. The control parameter in this case is, for example, the corrected rotation angle of the stage 3.

  Further, the device control unit 16 outputs the selected control parameter to the light amount adjustment unit control circuit 19. The light amount adjusting unit control circuit 19 controls the light amount adjusting unit 7 based on the input control parameter value. The control parameter in this case is, for example, the light amount aperture ratio of the light amount adjusting unit 7.

  Further, the device control unit 16 outputs the value of the selected control parameter to the light modulation unit control circuit 17. The light modulator control circuit 17 controls the light modulator 5 based on the input control parameter value. The control parameter in this case is, for example, the exposure start timing of the exposure head 13.

  Further, the apparatus control unit 16 outputs the drawing image data to the drawing pattern generation unit 15. The drawing pattern generation unit 15 generates a control signal based on the input data and outputs the control signal to the light modulation unit control circuit 17.

Next, a characteristic operation of the pattern drawing apparatus 1 will be described with reference to FIG. FIG. 6 is a flowchart showing a characteristic operation of the pattern drawing apparatus 1.
First, the exposure amount given to the photosensitive material layer of the photosensitive substrate 2 to be patterned is input to the input unit 12 by the user (step S1). Next, the photosensitive substrate 2 to be patterned is placed on the stage 2 (step S2).

  Next, the apparatus control unit 16 sets the scanning speed of the stage 2 corresponding to the exposure amount input by the user with reference to the lookup table 22 of the first storage unit 10 (step S3). Further, the device control unit 16 sets a control parameter value corresponding to the selected scanning speed with reference to the second storage unit 11 (step S4).

  Next, the device control unit 16 outputs the selected numerical data to the control circuits 17, 18, and 19 (step S5). Specifically, the apparatus control unit 16 outputs the scanning speed and control parameter values to the stage drive system control circuit 18. Further, the device control unit 16 outputs the value of the selected control parameter to the light amount adjustment unit control circuit 19 and the light modulation unit control circuit 17. Further, the apparatus control unit 16 outputs the drawing image data to the drawing pattern generation unit 15.

  Next, the drawing pattern generation unit 15 generates a control signal based on the input data, and outputs the control signal to the light modulation unit control circuit 17 (step S6).

  Next, each control circuit 17, 18, 19 controls the controlled object (step S7). Specifically, the light amount adjustment unit control circuit 19 controls the light amount adjustment unit 7. The light modulator control circuit 17 controls the light modulator 5. The stage drive system control circuit 18 controls the stage 3. Thereby, scanning exposure with high precision and high throughput is realized. The above is the characteristic operation of the pattern drawing apparatus 1.

Here, the amount of light to be given to the exposure head 13 during exposure drawing will be described.
The amount of light required for exposure drawing varies depending on the type and thickness of the photosensitive material layer of the photosensitive substrate 2. When the output of the light source 4 and the light sensitivity of the photosensitive material layer are constant, the amount of light to be given to each exposure head 13 at the time of drawing is proportional to the stage speed. That is, in order for the photosensitive material layer to obtain a necessary amount of light per unit area, it is necessary to increase the amount of light given to each exposure head 13 if the stage speed is high.

  Assuming that the amount of light output from the exposure head 13 is P and the stage speed is V, a relationship of P∝V (P is proportional to V) is established.

  As the photosensitivity (the amount of light necessary for exposure) of the photosensitive material layer increases, the amount of light to be given to each exposure head 13 also increases. Therefore, if the photosensitivity of the photosensitive material layer is Q, a relationship of P∝Q × V (P is proportional to Q and V) is established.

  By scanning the photosensitive material layer with the pattern of the scanning row 21, a strip-shaped exposure pattern is drawn on the photosensitive material layer. Illustration of the exposure pattern is omitted. If the amount of light applied to each exposure head 13 is the same, ideally, the line width of the exposure pattern as a drawing result is the same. However, in actuality, the line width of the exposure pattern as an exposure result may differ between the exposure heads 13 due to variations in the lens characteristics of the irradiation unit 6 or the like. For example, when the exposure amount increases due to variations in lens characteristics, etc., the line width of the exposure pattern increases. Conversely, when the exposure amount decreases, the line width of the exposure pattern decreases. In such a case, it is preferable to measure the line width of the exposure pattern, which is the drawing result, and obtain the optimum light amount given to each exposure head 13 based on the measurement result. Therefore, a proportional coefficient K is set in order to obtain the optimum light quantity.

That means
P = K × Q × V (1)
By obtaining K for which each of the exposure heads 13 holds, the amount of light to be given to each exposure head 13 at the time of drawing can be obtained.

When the equation (1) is transformed,
K = P / (Q × V) (2)
It becomes.

A specific example for obtaining K is shown below.
Referring to FIG. 2, the scanning head width of exposure head 13 is 5 (mm), the number of beam light emission areas 20 (hereinafter referred to as pixels 20) of exposure head 13 is 2000 (pixels), and the stage speed <V>. Is 400 (mm / sec), and the photosensitivity <Q> of the photosensitive material layer is 30 (mJ / cm ² ). ... (3)

The area where the exposure head 13 performs drawing in one second is
0.5 (cm) × 40 (cm) = 20 (cm ² )
It becomes.

In order to give this area an amount of light corresponding to photosensitivity 30 (mJ / cm ² ) = 30 (mW · sec / cm ² ) in 1 second,
A light quantity of P = 30 (mW · sec / cm ² ) ÷ 1 (sec) × 20 (cm ² ) = 600 (mW) is required.

Since the number of pixels 20 of the exposure head 13 is 2000 (pixels), the amount of light per pixel is
P = 600 (mW) / 2000 (pixel)
= 0.3 (mW / pixel) (4)
It becomes.

From equations (2), (3), (4)
K = P / (Q × V) = 0.3 ÷ (30 × 400) = 0.000025 (5)
It becomes.

If the unit of P is (μW / pixel),
K = P / (Q × V) = 300 ÷ (30 × 400) = 0.025 (6)
It becomes.

Thus, the proportional coefficient K of the exposure head 13 is obtained,
P = 0.025QV (7)
The relationship holds.

  However, Expression (7) is an expression that holds when the irradiation unit 6 and the like are in an ideal state with no variation in quality. Since there may be variations in the quality of the actual irradiation unit 6 or the like, it is necessary to measure the line width of the exposure pattern formed by exposure, and to correct equation (7) based on the measurement result.

  Therefore, as illustrated in FIG. 7, the first scanning rows 21 of the exposure heads (1), (2), and (3), the second scanning rows 21, the third scanning rows 21, and the like. The n-th scanning rows 21 are exposed to each other with the beam light whose light amount is reduced at the same aperture ratio in the light amount adjustment unit 7. In the example shown in FIG. 7, the exposure amount considered to be the exposure amount A is given to the first scan row 21, and the exposure amount considered to be the exposure amount A + N is given to the second scan row 21, The third scanning row 21 is given an exposure amount that is considered to be an exposure amount A + 2N. Each exposure head 13 is given a light amount with the same aperture ratio, but since there is a possibility that the illumination optical system 14 and the irradiation unit 6 are distorted, the same light amount is given to the same number of scanning rows 21. Not exclusively. Setting N to a small value improves accuracy.

In the example shown in FIG. 7, the exposure amount A is 24 (mJ / cm ² ), the exposure amount A + N is 25 (mJ / cm ² ), and the exposure amount A + 2N is 26 (mJ / cm ² ). The exposure amount A + 3N is 27 (mJ / cm ² ), and the exposure amount A + 4N is 28 (mJ / cm ² ). The photosensitivity of the photosensitive material layer is assumed to be 25 (mJ / cm ² ).

As a result of measuring the line width of the exposure pattern formed by scanning the scan row 21, the exposure pattern corresponding to the second scan row 21 in the exposure head (1) is appropriate to correspond to the light sensitivity 25 (mJ / cm ² ). It is assumed that the exposure pattern corresponding to the third scanning row 21 has an appropriate line width in the exposure head (2).

In this case, the following calculation is performed.
K1 = P / (Q × V)
= 300 × (25/30) ÷ (25 × 400) = 0.025 (8)

K2 = P / (Q × V)
= 300 × (26/30) ÷ (25 × 400) = 0.026 (9)

From equation (8)
For the exposure head (1),
P1 = 0.025QV (10)
Holds.
Since this is the same as Expression (7), it indicates that the optical system in the exposure head (1) is in an ideal state.

From equation (9)
For the exposure head (2),
P2 = 0.026QV (11)
Holds.
This indicates that, for example, the optical system in the exposure head (2) is distorted, and there is a slight light amount loss.

The value of K1 is a constant unique to the exposure head (1). Even when Q and V are changed, Expression (10) is established. The amount of light to be given to the exposure head (1) is obtained by substituting values for Q and V in the equation (10).
That is, P1 = 0.025 × 25 × 400
= 250 (μW / pixel)
It becomes.
What is necessary is just to adjust a light quantity with the light quantity adjustment part 7 (for example, attenuator) so that the light quantity of P1 may be given to the exposure head (1).

The value of K2 is a constant specific to the exposure head (2). Even when Q and V are changed, Expression (11) is established. The amount of light to be emitted by the exposure head (2) is obtained by substituting values for Q and V in the equation (11).
That is, P2 = 0.026 × 25 × 400
= 260 (μW / pixel)
It becomes.
What is necessary is just to adjust a light quantity with the light quantity adjustment part 7 (for example, attenuator) so that the light quantity of P2 may be given to the exposure head (2).

As described above, according to the pattern drawing apparatus 1, the first storage unit 10 includes a plurality of exposure amounts selected according to the photosensitivity of the photosensitive material layer, and a scanning speed suitable for each exposure amount. Are stored in association with each other. Therefore, even if the sensitivity of the photosensitive material layer is variously changed, it is possible to set a scanning speed suitable for each sensitivity.
In addition, the control unit 9 selects a scanning speed suitable for the exposure amount input from the input unit 12 from the scanning speeds stored in the first storage unit 10, and a control parameter suitable for the selected scanning speed. Is selected from the values of the control parameters stored in the second storage unit 11. The control unit 9 controls the scanning mechanism 8, the light amount adjustment unit 7, and the light modulation unit 5 based on the selected scanning speed and control parameter value. Therefore, even if the sensitivity of the photosensitive material layer is variously changed, control based on the scanning speed and the value of the control parameter suitable for each sensitivity is performed. Therefore, even if the sensitivity of the photosensitive material layer is variously changed, scanning exposure with high accuracy and large throughput can be performed.
Each scanning speed stored in the first storage unit 10 is a speed corresponding to the light amount when the light amount adjustment unit 7 does not adjust the light amount. The stage speed can be increased as the amount of light increases. Therefore, the stage speed is maximized when the amount of light is not adjusted. Therefore, it is possible to reliably increase the drawing throughput.

In the first embodiment, the lookup table stored in the first storage unit 10 may be changed as shown in FIG. That is, as shown in the drawing, when the exposure dose to be input is greater than 30 and 40 or less (mJ / cm ² ), the stage scanning speed is set to 300 (mm / sec). This is effective when a photosensitive material layer having a photosensitivity of 40 (mJ / cm ² ) is scanned and exposed at high speed.

  The present invention can be used for a pattern drawing apparatus that performs photolithography to manufacture a semiconductor substrate, a liquid crystal display, and a printed board, and in particular, can be used for a pattern drawing apparatus that includes a plurality of exposure heads.

The figure which shows the pattern drawing apparatus which concerns on 1st Embodiment of this invention. The figure which shows the beam light emission area | region (drawing pixel) in 1st Embodiment. The figure which shows a mode that exposure scanning is carried out with each exposure head in 1st Embodiment. The figure which shows the state scanned and exposed with each exposure head in 1st Embodiment. The figure which shows an example of the lookup table memorize | stored in the 1st memory | storage part in 1st Embodiment. The flowchart which shows the characteristic operation | movement of the pattern drawing apparatus which concerns on 1st Embodiment. The figure which shows the method of calculating | requiring the proportionality constant K of each exposure head in 1st Embodiment. The figure which shows the other example of the look-up table memorize | stored in the 1st memory | storage part in 1st Embodiment. It is a figure which shows the positional relationship of each exposure head, (a) is a figure which shows an ideal state, (b) is a figure which shows the state which mutually shifted | deviated to the scanning direction. The figure which shows the case where a scanning row has shifted between exposure heads

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pattern drawing apparatus 2 Photosensitive substrate 3 Stage 4 Light source 5 Light modulation part 6 Irradiation part 7 Light quantity adjustment part 8 Scan mechanism 9 Control part 10 1st memory | storage part 11 2nd memory | storage part 12 Input part 13 Exposure head 14 Illumination optical system 15 Drawing pattern generation unit 16 Device control unit 17 Light modulation unit control device 18 Stage drive system control circuit 19 Light amount adjustment unit control circuit 20 Beam light emission region 21 Scan train 22, 23 Look-up table

Claims (5)

A pattern drawing apparatus that exposes and draws a pattern on a substrate by irradiating light to the photosensitive material layer of the photosensitive substrate,
A stage on which a photosensitive substrate is installed;
A light source;
A light modulation unit that modulates light of the light source into light of a pattern to be drawn;
An irradiation unit that irradiates the photosensitive material layer with modulated light while moving relative to the substrate in the scanning direction;
A light amount adjusting unit for adjusting the amount of light incident on the light modulating unit;
A scanning mechanism that scans the irradiation unit relative to the stage along the scanning direction;
A control unit for controlling the light amount adjusting unit and the scanning mechanism;
A first storage unit that stores a plurality of exposure amounts selected according to the photosensitivity of the photosensitive material layer and a scanning speed suitable for each of the exposure amounts in association with each other;
A second storage unit that stores values of control parameters of the control unit suitable for the respective scanning speeds;
An input unit for inputting an exposure amount irradiated by the irradiation unit;
The control unit selects a scanning speed corresponding to the exposure amount input by the input unit from the scanning speeds stored in the first storage unit, and a control parameter value suitable for the selected scanning speed. Is selected from control parameter values stored in the second storage unit, and the scanning mechanism and the light amount adjusting unit are controlled based on the selected scanning speed and control parameter value. Drawing device. The light amount adjusting unit is
The attenuator is provided between the light source and the light modulation unit and reflects a part of the light of the input light source and outputs the light that is not reflected, thereby adjusting the light amount. The pattern drawing apparatus described in 1.   The pattern drawing apparatus according to claim 1, wherein each scanning speed stored in the first storage unit is a speed corresponding to a light amount when the light amount adjustment unit does not adjust the light amount.   The pattern drawing apparatus according to claim 1, wherein a plurality of exposure heads including the light modulation unit, the irradiation unit, and the light amount adjustment unit are arranged in parallel. The light amount adjusting unit is
The pattern drawing apparatus according to claim 1, wherein an amount of light of the light source is adjusted.

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