JP2003218001A - Aligner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aligner which is capable of exposing a substrate with high uniformity even when a plurality of light emitting elements are used as a light source. <P>SOLUTION: This aligner (100) is equipped with a plurality of light emitting elements (136), scanning means (112) and (114), and a plurality of optical filters (144). The scanning means (112) and (114) enable light radiating from the light emitting elements (136) to scan a photosensitive substrate in the prescribed scanning direction for exposing the substrate. The optical filters (144) are arranged in the optical paths of light emitted from the light emitting elements (136) respectively. The optical filters (144) function so as to reduce a difference between a maximum and a minimum in the distribution of light volumes emitted from the light emitting elements (136) for irradiating the surface of the substrate. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus for exposing a photosensitive substrate, and more particularly to an exposure apparatus having a plurality of light emitting elements as a light source.

[0002]

2. Description of the Related Art In an exposure apparatus, in order to prevent uneven exposure,
It is required to irradiate a substrate, which is an exposure target, with uniform light. In order to meet such requirements, the conventional exposure apparatus uses a single ultra-high pressure mercury lamp as a light source, and uses a reflection mirror or collimator to direct the light emitted from the mercury lamp into a large parallel area. It was converted into light, and the substrate was irradiated on it.

[0003]

However, the ultra-high pressure mercury lamp generally has a short service life, so that it has to be replaced frequently. Since this replacement work includes the work for adjusting the light quantity of the newly installed ultra-high pressure mercury lamp, it took time and effort. For this reason, frequent replacement of the ultra-high pressure mercury lamp has been a cause of lowering the throughput of the exposure apparatus. Further, the ultra-high pressure mercury lamp has a problem that it consumes a large amount of power and is not economical.

In order to solve the above problems, it is conceivable to use, as a light source of an exposure apparatus, a plurality of small-sized light emitting elements which are more durable and consume less power, instead of an ultra-high pressure mercury lamp. However, when a plurality of light emitting elements are used for the light source, the light emitted to the substrate has a non-uniform intensity distribution, and this causes a problem that uneven exposure occurs on the substrate.

Therefore, an object of the present invention is to provide an exposure apparatus which can expose a substrate substantially evenly while using a plurality of light emitting elements as a light source.

[0006]

In order to solve the above-mentioned problems, an exposure apparatus according to the present invention comprises a plurality of light emitting elements, a scanning means, and a plurality of optical filters. The scanning unit scans the light emitted from the plurality of light emitting elements on the substrate along a predetermined scanning direction in order to expose the photosensitive substrate. Each of the plurality of optical filters is arranged on each optical path of the light emitted from the plurality of light emitting elements. The plurality of optical filters function to reduce the difference between the maximum value and the minimum value in the light amount distribution of the light emitted from the plurality of light emitting elements to the surface of the substrate as a result of scanning. here,
A plurality of optical filters, if [delta] L of the difference between the maximum value and the minimum value of the light amount distribution, the maximum value of the light amount distribution of the example when there is no optical filter was _{L max, δL / L max <} 5% is satisfied As described above, it is preferable to reduce the difference between the maximum value and the minimum value of the light amount distribution. This is because the exposure unevenness of the substrate can be eliminated to the extent that there is no substantial problem. Needless to say, however, it is more preferable that the optical filter makes the amount of light emitted from the plurality of light emitting elements to the surface of the substrate as a result of scanning substantially constant regardless of the position on the substrate.

In the above exposure apparatus, for example, in each of the optical filters, the transmittance of the light emitted from the light emitting element has a distribution corresponding to the intensity distribution of the light emitted from the light emitting element. In this case, it is preferable that the transmittance changes in a direction orthogonal to the scanning direction and is uniform in the scanning direction. Further, for example, the optical filter may be formed so that the transmittance changes stepwise in the direction orthogonal to the scanning direction. By forming the optical filter so that the portion of the optical filter corresponding to the position where the light amount is the minimum in the light amount distribution does not substantially attenuate the transmitted light, the energy of the light emitted from the light emitting element can be efficiently used. The substrate can be exposed.

In the exposure apparatus according to the present invention, it is preferable that the plurality of light emitting elements are arranged two-dimensionally. Particularly, in the two-dimensional array, two or more light emitting elements are arranged at a first interval in a direction parallel to a predetermined reference line, and two or more rows of light emitting elements are arranged at a second interval in the scanning direction. In addition, it is preferable that each row of the light emitting elements is arranged so as to be displaced by a certain distance in the direction parallel to the reference line with respect to the other rows adjacent to each other in the scanning direction. When the diameter of the beam spot irradiated on the surface of the substrate by the light emitting element is d, the first interval is a, the number of rows of the light emitting element is m, and the constant distance is c, (d × m) ≧ a, And it is preferable that (c × m) = a is satisfied. When this condition is satisfied, the light from the plurality of light emitting elements is scanned on the substrate, so that the substrate can be exposed throughout.

As a light emitting element, it has durability,
It is desirable to use an inexpensive light emitting diode with low power consumption.

[0010]

DETAILED DESCRIPTION OF THE INVENTION An exposure apparatus according to an embodiment of the present invention will be described below with reference to the drawings. In addition,
In the following description, a plane parallel to the exposure surface of the substrate held by the exposure apparatus is called an xy plane, and two directions orthogonal to each other in the xy plane are called an x direction and ay direction, respectively.

FIG. 1 schematically shows the structure of the exposure apparatus 100 of this embodiment. As shown in FIG. 1, the exposure apparatus 100 is arranged on an exposure table 102, and the substrate 10 is moved to x,
Substrate stage 104 movably holding in two directions of y
And a substrate stage controller 106 that controls the operation of the substrate stage 104. Also, the exposure apparatus 100
Includes a mask stage 108 that holds the photomask 20 parallel to the exposed surface of the substrate 10. In the present embodiment, the mask stage 108 holds the photomask 20 so that there is a space of several microns to several tens of microns between the substrate 10 and the photomask 20. Alternatively, the mask stage 108 holds the photomask 20 so that the photomask 20 is in close contact with the exposed surface of the substrate 10.
Therefore, in this embodiment, the pattern drawn on the photomask 20 is exposed on the substrate 10 at a scale ratio of about 1: 1.

The exposure apparatus 100 includes a light source 110 for irradiating the substrate 10 with light, and an optical scanning mechanism for driving the light source 110 back and forth in a predetermined scanning direction (x direction in the case of the present embodiment). And 112. Optical scanning mechanism 1
When the light source 110 moves the light source 110 in the x direction,
Is scanned on the substrate 10 in the x direction. The exposure apparatus 100 further includes an optical scanning controller 114 that controls the operation of the optical scanning mechanism 112.

Next, the structure of the light source 110 used in the exposure apparatus 100 will be described in more detail. Figure 2
FIG. 4 is a perspective view showing a light source 110 when viewed obliquely from the substrate stage 104 side. The light source 110 includes a plurality of units U1, U2, ... Arranged in the scanning direction (x direction) of the light source 110.
..., equipped with Un. Each light source unit includes a plurality of light emitting elements 136 arranged two-dimensionally in a plane parallel to the exposure surface of the substrate 10.

In the present embodiment, the light source 110 is provided with a plurality of units, but this is not an essential requirement for the present invention, and another exposure apparatus according to the present invention has only a single unit U1. It can also be configured to have.
Therefore, in the following, for simplicity of description, the light source 110 will be described as having only the unit U1.

FIG. 3 is a partial cross-sectional view of the light source unit U1, showing a part of the cross section of the light source unit U1 along a plane perpendicular to the exposure surface of the substrate 10 and parallel to the y direction. There is. In the light source unit U1, a printed circuit board 134 is provided.
Are arranged, and the plurality of light emitting elements 136 described above are attached to the printed circuit board 134. In the case of the present embodiment, the light emitting element 136 is a light emitting diode (LED) that emits ultraviolet light. The light emitting diode has advantages such as high durability and low power consumption as compared with the ultra-high pressure mercury lamp.

A lens panel 138 is provided on the substrate stage 104 side of the light emitting element 136. The lens panel 138 is made of glass or light-transmissive resin,
A collimator lens 140 is formed at a position where the light emitted from each light emitting element 136 passes.

Further, the light emitting element 136 and the lens panel 13
The optical filter panel 142 is disposed between the optical filter panel 142 and the optical filter panel 8. The optical filter panel 142 is also made of glass or a light transmissive resin, and an optical filter 144 is formed at the position where the light rays emitted from each light emitting element 136 pass. The optical filter 144 is an optical filter for changing the intensity distribution of the light emitted from the light emitting element 136.

The light source unit U1 constructed as described above
Then, the light emitted from each light emitting element 136 first passes through the optical filter 144 to have its light intensity distribution adjusted,
Further, it is converted into parallel light by the collimator lens 140, and thereafter, the substrate 10 or the photomask 20 is irradiated with the light.

FIG. 4 shows the distribution of the transmittance of the optical filter 144 with respect to the light emitted from the light emitting element 136 in the y direction, that is, the distribution in the direction orthogonal to the scanning direction in which the light source 110 is scanned. In FIG. 4, the vertical axis α represents the light transmittance, and the horizontal axis Y represents the y-direction coordinates. On the horizontal axis Y, Y
= 0 indicates the center of the optical filter 144 in the y direction, and w / 2
And -w / 2 indicate the position of the end of the optical filter 144 in the y direction. As shown, the optical filter 14
The transmittance α of 4 is the center of the optical filter 144 (Y = 0)
At the minimum, from which y of the optical filter 144
It has a distribution that increases continuously and gradually toward the end of the direction. Further, the transmittance α is substantially 1 in a region having a predetermined width δy from the y-direction end of the optical filter 144.
It is 00%. That is, in this region, even if the light from the light emitting element 136 passes through the optical filter 144, its intensity is not attenuated.

The optical filter 144 of this embodiment is used.
Is configured such that the transmittance α changes only in the y direction and is constant in the x direction, that is, the scanning direction of the light source 110.

FIG. 5 is a diagram for explaining the arrangement of the light emitting elements 136 in the light source unit U1. In FIG. 5, a black dot p represents the position of the light emitting element 136, and a circular portion q indicated by a broken line is a beam formed by the light emitted from each light emitting element 136 through the collimator lens 140 on the substrate 10 or the photomask 20. It represents a spot.

In the light source unit of this embodiment, the equal intervals a
The rows of the light emitting elements 136 arranged in the y direction are
That is, a plurality of columns are arranged at equal intervals b in the scanning direction. In addition, the respective rows of the light emitting elements 136 are arranged so as to be displaced from each other by a constant distance c in the y direction. This is to prevent the beam spots q respectively formed by the two light emitting elements 136 in one light source unit from completely overlapping in the scanning direction when the light source unit is scanned in the x direction.

Further, assuming that the diameter of the beam spot is d and the number of rows of the light emitting elements 136 in one light source unit is m, the light emitting elements 136 are arranged so that the following expression is established;

[Equation 1]

[Equation 2] When Expressions (1) and (2) are satisfied, when the light source unit is scanned in the x direction, a shaded portion r in FIG.
And s, the light-emitting elements 136 in successive columns
The areas where the beam spots of the above pass on the substrate 10 partially overlap. For this reason, when the light source unit is scanned in the x direction, the light from the light source unit is applied to the entire surface of the substrate 10 and the light is not applied, and no unexposed area remains.

In the exposure apparatus 100 described above, the pattern of the photomask 20 is exposed and transferred onto the substrate 10 by the following operation. That is, first, the substrate stage control unit 106 adjusts the position of the substrate stage 104 to align the substrate 10 and the photomask 20. Next, the light scanning control unit 114 operates the light scanning mechanism 112 to move the light source 110 to the initial position. Here, the initial position means a position where the light source 110 is not located above the substrate 10 and the light emitted from the light source 110 is not directly emitted to the substrate 10. When the light source 110 is arranged at the initial position, the lighting control unit 126 then turns on the light emitting element 136 of the light source 110. Next, the optical scanning controller 114
Controls the light scanning mechanism 112 to control the light source 110 at x.
Scan at a constant speed in the direction. Thereby, the light source 110
However, while irradiating the substrate 10 with light, it passes above the substrate 10 from one end to the other end in the x direction. This allows
The substrate 10 is exposed. When the light source 110 completely passes over the substrate 10 and the light source 110 moves to a position where the light emitted from the light source 110 does not directly expose the substrate 10, the optical scanning control unit 114 stops the scanning of the light source 110. Then, the lighting control unit 126 turns off the light emitting element 136 of the light source 110. With the above, the exposure process in the exposure apparatus 100 is completed.

Next, how to determine the light transmittance α of the optical filter 144 shown in FIG. 4 will be described. FIG. 6 shows a state in which the light source 1 is not attached to the exposure apparatus 100.
When the substrate 10 is exposed by scanning 10 once in the x direction, the y direction distribution of the (integrated) amount of light emitted from the light source 110 to the substrate 10 is shown. In FIG. 6, the vertical axis L represents the (integrated) light amount, and the horizontal axis y represents the y coordinate.
In the figure, y = 0 is the center of the substrate 10 in the y direction, W / 2 and −.
W / 2 indicates the position of the end of the substrate 10 in the y direction. In the exposure apparatus 100, the light source 110 is x
Since the light source 11 is scanned at a constant speed in the direction,
The distribution of the amount of light emitted from 0 changes only in the y direction, and x
It does not change in the direction and is constant.

In FIG. 6, curves 150a to 150g
Shows the distribution of the amount of light with which the single light emitting element 136 irradiates the substrate 10 when the light source 110 is not provided with the optical filter 144. Here, assuming that the intensity distribution of the light emitted from the light emitting element 136 can be approximated by a Gaussian distribution, each of the curves 150a to 150f can be expressed by the following equation.

[Equation 3] However, y_cIs a light beam emitted from each light emitting element 136.
Y-coordinate of the central axis of w ₀Is the radius of the ray. Ray of
The radius is the maximum value (1
/ E^Two) The distance to the doubled position.

The y-direction distribution of the amount of light emitted to the substrate 10 is obtained as the sum of the distribution of the amount of light emitted from each light emitting element 136 (curves 150a to 150g), and in FIG.
It is shown by curve 152. As can be seen from the curve 152, when the light source 110 is not provided with the optical filter 144 and the light from each light emitting element 136 is applied to the substrate 10 as it is,
The distribution of the amount of light received by the substrate 10 has a maximum value L _max and a minimum value L
_It has a non-uniform distribution that goes up and down from _min . Note that the interval between the maximum values L _max adjacent to each other in the light amount distribution represented by the curve 152 is equal to the distance c described in FIG. 5, that is, the distance between the respective rows of the light emitting elements 136 in the y direction.

The transmittance α of the optical filter 144 shown in FIG. 4 is preferably L _max =, so that the maximum value L _max and the minimum value L _min in the distribution of the curve 152 are reduced.
L _min . Now curve 152 is y
Is expressed by the function L = L ₁₅₂ (y), the transmittance α of the optical filter 144 described above is (y _c −c / 2).
Within the range of <y <(y _c + c / 2),

[Equation 4] Is determined. In formula (4), (L ₁₅₂ (y) −
L _min ) represents the amount of light that exceeds L _min of the amount of light with which the substrate 10 is irradiated. Therefore, when the transmittance α of the optical filter 144 is determined based on the equation (4), the optical filter 144 attenuates the amount of light exceeding L _min from the light rays that are transmitted.

When the optical filter 144 having the transmittance α determined as described above is attached to the light source 110 and the substrate 10 is exposed, the distribution of the amount of light applied to the substrate 10 is shown by the straight line 156 in FIG. Thus, there is a flat distribution with a constant value L _min regardless of the position in the y direction. Therefore, when the optical filter 144 is attached to the light source 110, the exposure apparatus 100 can expose the substrate 10 with a uniform light amount.

The transmittance α of the optical filter 144 is
(Y) is (y_c-C / 2) <y <(y _c+ C / 2)
In the exceeding range, α (y) = 0 is set. this is,
(Y_c-C / 2) <y <(y_cRange exceeding + c / 2)
Is an area mainly exposed by another light emitting element 136.
Yes, other light arranged on the optical path of the other light emitting element 136
Of the amount of light emitted to the substrate 10 by the optical filter 144
This is because adjustment can be performed.

Although the exposure apparatus 100 has been described above, the exposure apparatus 100 is merely an embodiment of the present invention.
The exposure apparatus 100 can be variously modified within the scope of the technical idea of the present invention.

For example, in the above description, the transmittance α of the optical filter 144 is set so that the y-direction distribution of the light quantity applied to the substrate 10 becomes substantially flat. However, this is the maximum value in the light quantity distribution. And the difference δL between the minimum values is
The transmittance α may be set so as to be suppressed to such an extent that no substantial inconvenience occurs when 0 is exposed. Specifically, for example, when the maximum value of the light amount distribution without the optical filter 144 is L _max ,

[Equation 5] The distribution of the transmittance α of the optical filter 144 may be determined so that the relationship of

The transmittance α of the optical filter 144 is
It does not necessarily have to be changed continuously in the y direction, but may be changed stepwise. FIG. 7 shows a plan view of the optical filter 144 whose transmittance α changes stepwise as viewed from the light emitting element 136 side. In the figure, the broken line 146 indicates the optical filter 1 irradiated with the light from the light emitting element 136.
This is the area above 44.

In the optical filter 144 shown in FIG. 7, five types of regions 144a to 144e having different transmittances α are formed. The transmittance α is uniform in each of the regions 144a to 144e. Each of the regions 144a to 144e is a rectangular region whose long side is parallel to the x direction and whose short side is coincident with the x direction end of the optical filter 144. A region 144a is formed at the center of the optical filter 144, and the region 14a is formed toward the end of the optical filter 144 in the y direction.
4b to 144e are arranged in order. Transmittance α
Is the lowest in region 144a, from which region 14
It is gradually increasing toward 4e. The transmittance α of the region 144e is set so as not to substantially attenuate the transmitted light. The optical filter 144 whose transmittance α changes stepwise has the advantage that it can be manufactured, for example, at a lower cost than the optical filter 144 whose transmittance α changes continuously.

[0035]

As described above, in the present invention, the exposure apparatus is provided with the optical filter for reducing the difference between the maximum value and the minimum value in the light amount distribution of the light emitted from the plurality of light emitting elements to the substrate surface. Therefore, it is possible to provide an exposure apparatus that uniformly exposes a substrate using a plurality of light emitting elements.

[0036]

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a configuration of an exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a light source viewed obliquely from the substrate stage side.

FIG. 3 is a partial cross-sectional view of a light source unit.

FIG. 4 is a diagram showing a y-direction distribution of transmittance of an optical filter.

FIG. 5 is a diagram for explaining an arrangement of light emitting elements in a light source unit.

FIG. 6 is a diagram showing a y-direction distribution of the amount of light emitted from a light source onto the substrate when the substrate is exposed using the exposure apparatus of FIG.

FIG. 7 is a plan view showing an example of an optical filter whose transmittance changes stepwise.

[Explanation of symbols]

100 exposure equipment 110 light source 112 Optical scanning mechanism 114 Optical scanning controller 136 light emitting element 142 Optical filter panel 144 Optical filter

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] December 6, 2002 (2002.12.
6)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction content]

FIG. 4 shows the distribution of the transmittance of the optical filter 144 with respect to the light emitted from the light emitting element 136 in the y direction, that is, the distribution in the direction orthogonal to the scanning direction in which the light source 110 is scanned. In FIG. 4, the vertical axis α represents the light transmittance, and the horizontal axis Y represents the y-direction coordinates. On the horizontal axis Y, Y
= 0 indicates the center of the optical filter 144 in the y direction, 1/2
[omega] and -1/2 [omega] indicate the position of the end of the optical filter 144 in the y direction. As shown in the figure, the transmittance α of the optical filter 144 is equal to the center (Y =
0) at which the optical filter 144 is minimized.
Has a distribution that continuously and gradually increases toward the end in the y direction. Further, the transmittance α is substantially 100% in a region having a predetermined width δy from the y-direction end of the optical filter 144. That is, in this region, even if the light from the light emitting element 136 passes through the optical filter 144, its intensity is not attenuated.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Ishibashi Otomo             2-36 Maeno-cho, Itabashi-ku, Tokyo Asahikou             Gaku Kogyo Co., Ltd. F-term (reference) 2H097 CA03 CA11 GA45                 5F046 BA05 CA03 CB08 DA02

Claims (10)

[Claims] 1. A plurality of light emitting elements, and a scanning unit configured to scan the substrate with light emitted from the plurality of light emitting elements along a predetermined scanning direction in order to expose a photosensitive substrate. A plurality of optical filters, each of which is arranged on each optical path of the light emitted from the plurality of light emitting elements, wherein the plurality of optical filters are a result of the scanning, and the surface of the substrate from the plurality of light emitting elements. An exposure apparatus, which reduces a difference between a maximum value and a minimum value in a light amount distribution of light radiated on a substrate. 2. The plurality of optical filters have a difference between a maximum value and a minimum value in the light amount distribution as δL, and a maximum value of the light amount distribution obtained when the optical filter is not provided as L.
The exposure apparatus according to claim 1, wherein the difference between the maximum value and the minimum value in the light amount distribution is reduced so that δL / L _max <5% is satisfied when _max is set. 3. The optical filter, as a result of the scanning,
The exposure apparatus according to claim 1, wherein the amount of light emitted from the plurality of light emitting elements to the surface of the substrate is made substantially constant regardless of the position on the substrate. 4. The optical filter according to claim 1, wherein a transmittance of light emitted from the light emitting element has a distribution corresponding to an intensity distribution of light emitted from the light emitting element. Exposure equipment. 5. The exposure apparatus according to claim 4, wherein the transmittance changes in a direction orthogonal to the scanning direction and is uniform in the scanning direction. 6. The exposure apparatus according to claim 5, wherein the transmittance changes stepwise in a direction orthogonal to the scanning direction. 7. The exposure apparatus according to claim 4, wherein the portion of the optical filter corresponding to the position where the light amount is minimum in the light amount distribution does not substantially attenuate the transmitted light. 8. The plurality of light emitting elements are two-dimensionally arrayed, and in the two-dimensional array, the two or more light emitting elements are arranged at a first interval in a direction parallel to a predetermined reference line. Two or more rows of elements are arranged at a second interval in the scanning direction, and each row of the light emitting elements is parallel to the reference line with respect to another row adjacent to the scanning direction. The exposure apparatus according to claim 1, wherein the exposure apparatus is arranged so as to be displaced by a predetermined distance. 9. When the diameter of the beam spot with which the light emitting element irradiates the surface of the substrate is d, the first interval is a, the number of rows of the light emitting element is m, and the constant distance is c, 9. The exposure apparatus according to claim 8, wherein (d × m) ≧ a and (c × m) = a are satisfied. 10. The exposure apparatus according to claim 1, wherein the light emitting element is a light emitting diode.