阅读说明：本技术 曝光用的光源装置、曝光装置及曝光方法 (Light source device for exposure, exposure device and exposure method ) 是由 松坂昌明 榎本芳幸 高濑和博 矢部俊一 松下智恒 于 2020-03-02 设计创作，主要内容包括：本发明提供一种曝光用的光源装置,使用该光源装置的曝光装置以及曝光方法,其能够将具有不同的峰值波长的多个LED元件的光合成,且紧凑地构成。具备：第一LED阵列(71),其具有发出第一峰值波长的光的多个第一LED元件(72)；第二LED阵列(75),其具有发出与所述第一峰值波长不同的第二峰值波长的光的第二LED元件(76)；光合成元件(80),其具有使特定的波段的光透过且使其他的波段的光反射的两个分色膜(81)且将第一和第二LED阵列(71、75)的光合成；以及复眼透镜(65),其被通过所述合成元件(80)而合成的光入射。(The invention provides a light source device for exposure, an exposure device using the light source device and an exposure method, which can synthesize light of a plurality of LED elements with different peak wavelengths and have compact structure. The disclosed device is provided with: a first LED array (71) having a plurality of first LED elements (72) that emit light at a first peak wavelength; a second LED array (75) having second LED elements (76) that emit light at a second peak wavelength that is different from the first peak wavelength; a light combining element (80) that combines light from the first and second LED arrays (71, 75), and that has two dichroic films (81) that transmit light in a specific wavelength band and reflect light in other wavelength bands; and a fly-eye lens (65) to which the light synthesized by the synthesizing element (80) is incident.)

1. A light source device for exposure, comprising:

a first LED array having a plurality of first LED elements emitting light at a first peak wavelength;

a second LED array having a plurality of second LED elements emitting light at a second peak wavelength different from the first peak wavelength;

a light combining element that combines light of the first LED array and the second LED array; and

a fly-eye lens to which the light synthesized by the light synthesizing element is incident,

the light source device for exposure is characterized in that,

the light combining element includes two dichroic films that transmit light in a specific wavelength band and reflect light in another wavelength band, the two dichroic films being arranged in a substantially V-shape so as to be inclined with respect to an optical axis direction from the light combining element toward the fly eye lens and to be in close contact with the fly eye lens side,

the first LED array is disposed on the opposite side of the fly-eye lens with respect to the light combining element in the optical axis direction,

the second LED array is disposed on a side of the light combining element so as to intersect the optical axis direction.

2. The light source device for exposure according to claim 1,

a peak wavelength of light emitted from any one of the first LED element and the second LED element is 360 to 380nm,

300 to 355nm or 385 to 410nm of a peak wavelength of light irradiated from the other of the first LED element and the second LED element,

the first LED element and the second LED element have a difference in peak wavelength of 20nm or more.

3. The light source device for exposure according to claim 1 or 2,

the length of the second LED array disposed on the side of the light combining element is shorter than the length of the first LED array disposed on the opposite side of the fly-eye lens with respect to the light combining element.

4. The light source device for exposure according to any one of claims 1 to 3,

the light combining elements are two dichroic mirrors or dichroic prisms.

5. The light source device for exposure according to claim 1,

the light synthesizing element is two dichroic mirrors having the dichroic films respectively,

end portions of the dichroic mirrors are cut parallel to the optical axis direction.

6. The light source device for exposure according to claim 5,

the device is also provided with two dichroic mirror fixing frames which respectively fix the dichroic mirrors and are opened at one side where the two dichroic mirrors are tightly attached,

the front end of the dichroic mirror fixing frame on the fly-eye lens side is cut at right angles to the optical axis direction.

7. The light source device for exposure according to any one of claims 1 to 6,

the second LED array has two second LED arrays of two kinds, and the two second LED arrays of two kinds are alternately arranged at intervals of 90 ° on a plane orthogonal to the optical axis direction.

8. An exposure apparatus is characterized by comprising:

an illumination device having the light source device for exposure according to any one of claims 1 to 7;

a workpiece support portion that supports a workpiece; and

a mask supporting part supporting a mask;

the exposure device irradiates the work with light emitted from the illumination device through the mask to transfer the pattern of the mask to the work.

9. An exposure method is characterized in that,

the exposure apparatus according to claim 8, wherein the pattern of the mask is transferred to the workpiece by irradiating the workpiece with light emitted from the illumination apparatus through the mask.

10. A light source device for exposure, comprising:

a plurality of first LED elements that emit light having a first peak wavelength in a range of 360 to 380nm corresponding to a photosensitive wavelength of a polymerization initiator of a photosensitive material provided on a substrate; and a plurality of second LED elements emitting light of a second peak wavelength in a range of 300 to 355nm corresponding to a photosensitive wavelength of a polymerization initiator of a photosensitive material provided on the substrate,

the light of the first LED element and the light of the second LED element are mixed and emitted to the fly-eye lens.

11. The light source device for exposure according to claim 10,

an LED array having a mixed configuration of the first LED element and the second LED element.

12. The light source device for exposure according to claim 10, comprising:

a first LED array having a plurality of said first LED elements;

a second LED array having a plurality of said second LED elements; and

a light combining element that combines light of the first LED array and light of the second LED array,

the light combining element has a color separation film that transmits light of a specific wavelength band and reflects light of other wavelength bands, the color separation film being disposed so as to be inclined with respect to an optical axis direction from the light combining element toward the fly eye lens,

either one of the first LED array and the second LED array is disposed on an opposite side of the fly-eye lens with respect to the light combining element in the optical axis direction,

the other of the first LED array and the second LED array is disposed on a side of the light combining element so as to intersect the optical axis direction.

13. An exposure apparatus, comprising:

an illumination device having the light source device for exposure according to any one of claims 10 to 12;

a workpiece support portion that supports a workpiece; and

a mask supporting part supporting a mask;

the exposure device irradiates the work with light emitted from the illumination device through the mask to transfer the pattern of the mask to the work.

14. An exposure method, characterized in that the exposure apparatus according to claim 13 is used, and light irradiated from the illumination apparatus is irradiated to the workpiece through the mask to transfer a pattern of the mask to the workpiece.

Technical Field

The present invention relates to a light source device for exposure, an exposure apparatus, and an exposure method, and more particularly, to a light source device for exposure, an exposure apparatus, and an exposure method, in which light emitted from an LED element is used as a light source.

Background

In an exposure apparatus used for photolithography of flat panel displays, printed circuit boards, semiconductor devices, and the like, a mercury lamp has been conventionally used as a UV light source. However, in recent years, restrictions on the use of mercury have become severe, and LED of a UV light source has been required.

Here, when a conventional resist matching the wavelength band of the mercury lamp is used as it is, the wavelength band of the LED element having a single wavelength is narrower than that of the mercury lamp. Therefore, a technique of combining LED elements having a plurality of wavelengths corresponding to g-line (436nm), h-line (405nm), and i-line (365nm) of a high-pressure mercury lamp, which outputs a strong mercury lamp, as a UV light source is known (for example, see patent documents 1 and 2).

Patent document 1 describes a light source device that uses an X-shaped dichroic mirror to multiplex UV light emitted from a plurality of LED elements that emit light having wavelengths corresponding to g-line (436nm), h-line (405nm), and i-line (365nm) with high output in a high-pressure mercury lamp. Patent document 2 discloses an LED-type ultraviolet irradiator including: a plurality of LED light sources which respectively emit UV light in the wave bands of 360 nm-380 nm, 390 nm-410 nm and 420 nm-450 nm; and a plurality of dichroic mirrors arranged with respect to the respective LED light sources. Further, patent document 2 describes the use of UV LED light that emits at a wavelength of less than 300nm, for example, nominally 240 nm.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2018-10294

Patent document 2: japanese laid-open patent publication No. 2010-263218

Disclosure of Invention

Technical problem to be solved by the invention

Further, the wavelength of the UV light source is preferably set so that the power consumption of the LED light source is small, and the cooling time due to heat generation of the light source can be reduced. In an exposure apparatus, in general, in order to reduce the number of components, effectively utilize the space in the apparatus, and reduce the weight, it is necessary to make a UV light source compact. Although each LED element is provided with a condenser lens, if an optical member such as a convex lens is not used separately, light emitted from the LED array tends to be not parallel and spread. Therefore, the optical path length is shortened, and the necessity of making the light source device compact is high. In particular, in an exposure apparatus for a display, a large area needs to be exposed at one time, and thus the light source size is increased and the necessity for compactness is high.

The light source device described in patent document 1 uses an X-shaped dichroic mirror to reduce the installation area, but there is room for further compactness. The LED-type ultraviolet irradiator described in patent document 2 uses 3 or more dichroic mirrors in series, and thus has room for improvement as a compact LED light source.

The inventors have also conducted experiments using conventional resists and found a resist having high exposure sensitivity under conditions shorter than the wavelength of i-line (365 nm). This is considered to be because: the polymerization initiator of the resist absorbs not only the absorption peak wavelength but also the peripheral wavelengths, but if the absorption wavelength band extends to the visible light range, there may be a problem depending on the use of the resist, and therefore, the absorption peak wavelength is intentionally set to a wavelength shorter than the g-line, h-line, and i-line of the mercury lamp. Examples of such applications include resists for color filters of displays and image sensors. Therefore, a light source device that more efficiently sensitizes such a resist is also desired.

The present invention has been made in view of the above-described problems, and an object thereof is to provide a light source device for exposure, an exposure apparatus using the light source device, and an exposure method, each of which is configured to combine light from a plurality of LED elements having different peak wavelengths and is compact.

Means for solving the problems

The above object of the present invention is achieved by the following structure.

(1) A light source device for exposure, comprising:

a first LED array having a plurality of first LED elements emitting light at a first peak wavelength;

a second LED array having a plurality of second LED elements emitting light at a second peak wavelength different from the first peak wavelength;

a light combining element that combines light of the first LED array and the second LED array; and

a fly-eye lens to which the light synthesized by the light synthesizing element is incident,

in the light source device for exposure, the light source device,

the light combining element includes two dichroic films that transmit light in a specific wavelength band and reflect light in another wavelength band, the two dichroic films being arranged in a substantially V-shape so as to be inclined with respect to an optical axis direction from the light combining element toward the fly eye lens and to be in close contact with the fly eye lens side,

the first LED array is disposed on the opposite side of the fly-eye lens with respect to the light combining element in the optical axis direction,

the second LED array is disposed on a side of the light combining element so as to intersect the optical axis direction.

(2) The light source device for exposure according to (1), wherein,

a peak wavelength of light emitted from any one of the first LED element and the second LED element is 360 to 380nm,

300 to 355nm or 385 to 410nm of a peak wavelength of light irradiated from the other of the first LED element and the second LED element,

the first LED element and the second LED element have a difference in peak wavelength of 20nm or more.

(3) The light source device for exposure according to (1) or (2), wherein,

the length of the second LED array disposed on the side of the light combining element is shorter than the length of the first LED array disposed on the opposite side of the fly-eye lens with respect to the light combining element.

(4) The light source device for exposure according to any one of (1) to (3),

the light combining elements are two dichroic mirrors or dichroic prisms.

(5) The light source device for exposure according to (1), wherein,

the light synthesizing element is two dichroic mirrors having the dichroic films respectively,

end portions of the dichroic mirrors are cut parallel to the optical axis direction.

(6) The light source device for exposure according to (5), wherein,

the device is also provided with two dichroic mirror fixing frames which respectively fix the dichroic mirrors and are opened at one side where the two dichroic mirrors are tightly attached,

the front end of the dichroic mirror fixing frame on the fly-eye lens side is cut at right angles to the optical axis direction.

(7) The light source device for exposure according to any one of (1) to (6),

the second LED array has two second LED arrays of two kinds, and the two second LED arrays of two kinds are alternately arranged at intervals of 90 ° on a plane orthogonal to the optical axis direction.

(8) An exposure apparatus includes:

an illumination device having the light source device for exposure according to any one of (1) to (7);

a workpiece support portion that supports a workpiece; and

a mask supporting part supporting a mask;

the exposure device irradiates the work with light emitted from the illumination device through the mask to transfer the pattern of the mask to the work.

(9) A method for exposing a light source to light,

using the exposure apparatus described in (8), the pattern of the mask is transferred to the workpiece by irradiating the workpiece with light irradiated from the illumination apparatus through the mask.

(10) A light source device for exposure, comprising:

a plurality of first LED elements that emit light of a first peak wavelength in a range of 360 to 380nm corresponding to a photosensitive wavelength of a polymerization initiator of a photosensitive material provided on a substrate; and a plurality of second LED elements emitting light of a second peak wavelength in a range of 300 to 355nm corresponding to a photosensitive wavelength of a polymerization initiator of a photosensitive material provided on the substrate,

the light of the first LED element and the light of the second LED element are mixed and emitted to the fly-eye lens.

(11) The light source device for exposure according to (10), wherein,

an LED array having a mixed configuration of the first LED element and the second LED element.

(12) The light source device for exposure according to (10), comprising:

a first LED array having the plurality of first LED elements;

a second LED array having the plurality of second LED elements; and

a light combining element that combines light of the first LED array and light of the second LED array,

the light combining element has a color separation film that transmits light of a specific wavelength band and reflects light of other wavelength bands, the color separation film being disposed so as to be inclined with respect to an optical axis direction from the light combining element toward the fly eye lens,

either one of the first LED array and the second LED array is disposed on an opposite side of the fly-eye lens with respect to the light combining element in the optical axis direction,

the other of the first LED array and the second LED array is disposed on a side of the light combining element so as to intersect the optical axis direction.

(13) An exposure apparatus, comprising:

an illumination device having the light source device for exposure according to any one of (10) to (12);

a workpiece support portion that supports a workpiece; and

a mask supporting part supporting a mask;

the exposure device irradiates the work with light emitted from the illumination device through the mask to transfer the pattern of the mask to the work.

(14) An exposure method wherein the exposure device of (13) is used, and light irradiated from the illumination device is irradiated to the workpiece through the mask to transfer a pattern of the mask to the workpiece.

Effects of the invention

According to the light source device for exposure, the exposure apparatus using the same, and the exposure method of the present invention, it is possible to compactly configure the light source device capable of combining lights emitted from a plurality of LED elements having different peak wavelengths, and it is possible to efficiently make a photosensitive material sensitive to the combined light, and it is possible to improve the exposure work efficiency.

Drawings

Fig. 1 is a front view of an exposure apparatus according to a first embodiment of the present invention.

Fig. 2 is a diagram showing a configuration of the lighting device shown in fig. 1.

Fig. 3 is a schematic configuration diagram of the light source device of the first embodiment.

Fig. 4(a) is a graph showing the transmittance of a dichroic mirror as an example, and (b) is an enlarged view of the IV portion of (a).

Fig. 5(a) is a graph showing the reflectance of the dichroic mirror of fig. 4, and (b) is an enlarged view of the V portion of (a).

Fig. 6 is a schematic configuration diagram of a light source device according to a second embodiment.

Fig. 7(a) is a side view showing a mounting state of a dichroic mirror as a light source device of a third embodiment, and (b) is a view seen from a direction a of (a).

Fig. 8(a) is a side view showing another mounting state of a dichroic mirror of a light source device as a modification of the third embodiment, and (B) is a view seen from the B direction of (a).

Fig. 9 is a schematic plan view showing two types of second LED arrays and two dichroic mirrors arranged on a plane perpendicular to the optical axis direction in the case of the light source apparatus according to the fourth embodiment.

Fig. 10 is a schematic configuration diagram of a light source device according to a modification of the present invention using a dichroic prism.

Fig. 11 is a front view of an LED array of a light source device according to another modification of the present invention.

Fig. 12 is a front view of an LED array of a light source device according to still another modification of the present invention.

Description of the symbols

65 fly-eye lens

70, 70A, 70B light source device

71 first LED array

72 first LED element

75, 75A, 75B second LED array

76, 76A, 76B second LED element

78LED array (light source device)

80, 80A, 80B light-combining element (dichroic mirror)

81 color separation film

83 end portion

85 dichroic mirror fixing frame

180 light synthesis component (color separation prism)

M mask

PE proximity exposure device

W workpiece (baseplate)

Length of L1 first LED array

Length of L2 second LED array

Detailed Description

(first embodiment)

Hereinafter, a first embodiment of an exposure apparatus according to the present invention will be described in detail with reference to the drawings. As shown in fig. 1, the proximity exposure apparatus PE uses a mask M smaller than a workpiece W as an exposure target material, holds the mask M by a mask stage (mask supporting portion) 1, holds the workpiece W by a workpiece stage (workpiece supporting portion) 2, and irradiates pattern exposure light from an illumination apparatus 3 toward the mask M in a state where the mask M and the workpiece W are disposed in proximity to each other with a predetermined exposure gap therebetween, thereby transferring the pattern exposure of the mask M onto the workpiece W. Further, the workpiece stage 2 is moved stepwise in two axial directions, i.e., the X-axis direction and the Y-axis direction, with respect to the mask M, and exposure transfer is performed for each step.

In order to step the workpiece stage 2 in the X-axis direction, an X-axis stage feed mechanism 5 that steps an X-axis feed stage 5a in the X-axis direction is provided on the apparatus base 4. In order to step the workpiece stage 2 in the Y-axis direction, a Y-axis stage feed mechanism 6 for stepping the Y-axis feed stage 6a in the Y-axis direction is provided on an X-axis feed stage 5a of the X-axis stage feed mechanism 5. The workpiece stage 2 is provided on a Y-axis feed table 6a of the Y-axis table feed mechanism 6. The workpiece W is held on the upper surface of the workpiece stage 2 in a vacuum-sucked state by a workpiece chuck or the like. Further, a substrate-side displacement sensor 15 for measuring the height of the lower surface of the mask M is disposed on the side portion of the workpiece stage 2. Therefore, the substrate-side displacement sensor 15 can move in the X, Y-axis direction together with the workpiece stage 2.

A plurality of (4 in the illustrated embodiment) guide rails 51 of an X-axis linear guide are arranged in the X-axis direction on the apparatus base 4, and a slider 52 fixed to the lower surface of the X-axis feed table 5a is straddled on each guide rail 51. Thereby, the X-axis table 5a is driven by the first linear motor 20 of the X-axis table feeding mechanism 5 and can reciprocate in the X-axis direction along the guide rail 51. Further, a plurality of guide rails 53 of the Y-axis linear guide are arranged in the Y-axis direction on the X-axis feed table 5a, and a slider 54 fixed to the lower surface of the Y-axis feed table 6a is straddled on each guide rail 53. Thereby, the Y-axis feed table 6a is driven by the second linear motor 21 of the Y-axis stage feed mechanism 6 and can reciprocate in the Y-axis direction along the guide rail 53.

In order to move the workpiece stage 2 in the vertical direction, a vertical coarse adjustment device 7 and a vertical fine adjustment device 8 are provided between the Y-axis stage feed mechanism 6 and the workpiece stage 2, the vertical coarse adjustment device 7 has a large positioning resolution but a large movement stroke and a large movement speed, and the vertical fine adjustment device 8 can perform positioning at a higher resolution than the vertical coarse adjustment device 7 and finely move the workpiece stage vertically so as to finely adjust the gap between the facing surfaces of the mask M and the workpiece W to a predetermined amount.

The vertical rough adjustment device 7 moves the workpiece stage 2 up and down with respect to the fine adjustment stage 6b by an appropriate drive mechanism provided on the fine adjustment stage 6b described later. The stage coarse adjustment shafts 14 fixed to 4 positions on the bottom surface of the workpiece stage 2 are engaged with linear bearings 14a fixed to the fine movement stage 6b, and are guided in the vertical direction with respect to the fine movement stage 6 b. Further, the vertical rough adjustment device 7 is desired to have high repetitive positioning accuracy even if the resolution is low.

The vertical fine adjustment device 8 includes a fixed table 9 fixed to the Y-axis feed table 6a and a guide rail 10 of a linear guide attached to the fixed table 9 in a state where an inner end side thereof is inclined obliquely downward, and a nut (not shown) of a ball screw is coupled to a slider 12 reciprocating along the guide rail 10 via a slider 11 straddling the guide rail 10, and an upper end surface of the slider 12 is in slidable contact in a horizontal direction with respect to a flange 12a fixed to the fine adjustment stage 6 b.

When the screw shaft of the ball screw is rotationally driven by the motor 17 attached to the fixed base 9, the nut, the slider 11, and the slider 12 move obliquely along the guide rail 10 as a unit, and the flange 12a thereby slightly moves up and down.

Instead of driving the slide 12 by the motor 17 and the ball screw, the vertical trimming device 8 may drive the slide 12 by a linear motor.

The vertical trimming device 8 is provided with 1 on one end side (left end side in fig. 1) in the Y axis direction of the Z-axis feed table 6a, two on the other end side, and 3 in total, and is independently driven and controlled. Thus, the vertical fine adjustment device 8 independently finely adjusts the height of the flange 12a at 3 locations based on the measurement results of the amount of clearance between the mask M and the workpiece W at a plurality of locations of the clearance sensor 27, and finely adjusts the height and inclination of the workpiece stage 2.

In addition, when the height of the workpiece stage 2 can be sufficiently adjusted by the vertical fine adjustment device 8, the vertical coarse adjustment device 7 may be omitted.

Further, a bar mirror 19 facing the Y-axis laser interferometer 18 for detecting the position of the workpiece stage 2 in the Y-axis direction and a bar mirror (both not shown) facing the X-axis laser interferometer for detecting the position of the workpiece stage 2 in the X-axis direction are provided on the Y-axis feed table 6 a. The bar mirror 19 facing the Y-axis laser interferometer 18 is arranged along the X-axis direction on the side of the Y-axis feed stage 6a, and the bar mirror facing the X-axis laser interferometer is arranged along the Y-axis direction on the side of one end of the Y-axis feed stage 6 a.

The Y-axis laser interferometer 18 and the X-axis laser interferometer are arranged so as to always face the corresponding strip mirrors, and are supported by the apparatus base 4. Two Y-axis laser interferometers 18 are provided so as to be separated in the X-axis direction. The Y-axis feed stage 6a, and hence the position of the workpiece stage 2 in the Y-axis direction and the deflection error are detected by the two Y-axis laser interferometers 18 via the strip mirrors 19. Further, the X-axis feed stage 5a and, further, the position of the workpiece stage 2 in the X-axis direction are detected by the X-axis laser interferometer via the opposing strip mirrors.

The mask stage 1 includes: a mask base frame 24 formed of a substantially rectangular frame body; and a mask frame 25 inserted through a gap into a central opening of the mask base frame 24 and supported so as to be movable in X, Y and θ directions (in the plane X, Y), wherein the mask base frame 24 is held at a fixed position above the workpiece stage 2 by a support column 4a protruding from the apparatus base 4.

A frame-shaped mask holder 26 is provided on the lower surface of the central opening of the mask frame 25. That is, a plurality of mask holder suction grooves connected to a vacuum suction device, not shown, are provided on the lower surface of the mask frame 25, and the mask holder 26 is suction-held by the mask frame 25 via the plurality of mask holder suction grooves.

A plurality of mask suction grooves (not shown) for sucking the peripheral edge portion of the mask M, on which the mask pattern is not drawn, are opened in the lower surface of the mask holder 26, and the mask M is detachably held on the lower surface of the mask holder 26 by a vacuum suction device (not shown) via the mask suction grooves.

As shown in fig. 2, the illumination device 3 of the exposure apparatus PE of the present embodiment includes: a light source device 70 for ultraviolet irradiation; a plane mirror 66 for changing the direction of the optical path EL emitted from the fly-eye lens 65 of the light source device 70; a collimator mirror 67 for irradiating the light from the light source device 70 as parallel light; and a flat mirror 68 that irradiates the parallel light toward the mask M.

In the illumination device 3, light emitted from the light source device 70 is incident on the incident surface of the fly eye lens 65. The fly-eye lens 65 is used to make the incident light have an illuminance distribution as uniform as possible on the irradiation surface. Then, the light emitted from the exit surface of the fly-eye lens 65 is changed in its traveling direction by the plane mirror 66, the collimator mirror 67, and the plane mirror 68, and is converted into parallel light. Then, the parallel light is irradiated substantially perpendicularly to the mask M held on the mask stage 1, and further to the surface of the workpiece W held on the workpiece stage 2, as pattern exposure light, and the pattern of the mask M is exposed and transferred to the workpiece W.

Next, the light source device 70 will be described in detail with reference to fig. 3. The light source device 70 of the present embodiment includes: first and second LED arrays 71, 75 that irradiate light having different peak wavelengths from each other; dichroic mirrors 80(80A, 80B) which are light combining elements for combining light beams having different peak wavelengths emitted from the first and second LED arrays 71, 75; and a fly-eye lens 65 including a plurality of lens elements 65a arranged in a matrix.

The first LED array 71 has a plurality of first LED elements 72 arranged two-dimensionally. The plurality of first LED elements 72 irradiate UV light having a peak wavelength (first peak wavelength) of any value of 360-380 nm, for example. The peak wavelength of the first LED element 72 is preferably 360 to 370nm, and more preferably 365 nm.

The second LED array 75 has a plurality of second LED elements 76 arranged two-dimensionally. The plurality of second LED elements 76 irradiate UV light having a peak wavelength (second peak wavelength) of any value of 300 to 355nm or 385 to 410nm, for example. The peak wavelength of the second LED element 76 is preferably 300 to 355nm, more preferably 325 to 355nm, and still more preferably 335 nm.

The first LED element 72 and the second LED element 76 are selected so that the peak wavelengths of the light differ by 20nm or more. The reason why the peak wavelengths of the light of the first LED element 72 and the second LED element 76 are different by 20nm or more is that the dichroic mirror 80 needs to be different in the two synthesized wavelengths by 20nm or more due to its performance.

When the peak wavelength of the first LED element 72 is, for example, 365nm, the peak wavelength of the second LED element 76 may be 345nm or less, or 385nm or more.

The dichroic mirror 80 as a light combining element is an optical element having the following characteristics: a thin film (dichroic film) 81 such as a dielectric multilayer film is formed on a plate-like transparent medium 82 made of glass, plastic or the like, and reflects light in a specific wavelength band and transmits light in other wavelength bands.

The 2 dichroic mirrors 80A and 80B (two dichroic films 81) of the substantially equal length L3 of the dichroic mirror 80 are arranged in a substantially V-shape so as to be inclined with respect to the optical axis direction L (i.e., the direction along the optical path EL) from the dichroic mirror 80 toward the fly-eye lens 65 and to be in close contact with the fly-eye lens side. In the present embodiment, the two dichroic mirrors 80A and 80B are combined at an angle of substantially 90 °.

The first LED array 71 is disposed facing the opening side (the side opposite to the fly-eye lens 65 with respect to the dichroic mirror 80 in the optical axis direction L, and the left side in fig. 3) of the V-shaped 2 pieces of dichroic mirrors 80A, 80B. The second LED arrays 75 are arranged on both sides (upper and lower sides in fig. 3) of the V-shaped 2-piece dichroic mirrors 80A and 80B, respectively, so as to intersect with (orthogonal to) the optical axis direction L. Thus, the first LED array 71 and the second LED array 75 are opposed to the V-shaped dichroic mirror 80A or 80B at an angle of substantially 45 °.

In the present embodiment, the second LED array 75 is orthogonal to the optical axis direction L includes not only a case where it is strictly orthogonal but also a case where it is orthogonal to the extent that the directivity of light entering the fly-eye lens 65 from the second LED array 75 is allowed.

In addition, the number of second LED elements 76 of the second LED array 75 is 1/2 the number of first LED elements 72 of the first LED array 71. That is, the length L2 of the second LED array 75 is substantially 1/2 of the length L1 of the first LED array 71, and is 1/√ 2 of the length L3 of the dichroic mirror 80A or 80B. Accordingly, all light emitted from the first LED array 71 passes through the dichroic mirror 80A or 80B, all light emitted from the two second LED arrays 75 is reflected by the dichroic mirror 80A or 80B, and light emitted from the first LED array 71 and light emitted from the second LED arrays 75 are combined and incident on the incident surface of the fly eye lens 65.

In this way, the 2 pieces of dichroic mirrors 80A, 80B are arranged in a substantially V shape so as to be in close contact with the fly eye lens 65 side, the first LED array 71 is arranged on the opposite side of the fly eye lens 65 with respect to the V-shaped dichroic mirrors 80A, 80B in the optical axis direction L, and the second LED array 75 is arranged on both sides of the V-shaped dichroic mirrors 80A, 80B so as to be divided orthogonally with respect to the optical axis direction L, whereby the length from the first LED array 71 to the fly eye lens 65 can be shortened, and the light source device 70 can be configured compactly. In addition, by disposing the first LED array 71 close to the fly-eye lens 65, the optical efficiency is improved.

In fig. 3, the first LED array 71 is set to a main wavelength having a peak wavelength at any value of 360 to 380nm, and the second LED array 75 is set to a sub-wavelength having a peak wavelength at any value of 300 to 355nm or 385 to 410nm, for example. However, in the present embodiment, the first LED array 71 is not limited to this, and the sub-wavelength having a peak wavelength at any value of 300 to 355nm or 385 to 410nm may be used as the first LED array 71, and the main wavelength having a peak wavelength at any value of 360 to 380nm may be used as the second LED array 75.

Since the optical efficiency of the reflected light reflected by the dichroic mirrors 80A and 80B is higher than that of the transmitted light, the optical efficiency can be appropriately selected according to the sensitivity of the resist used. The lengths of the first LED array 71, the second LED array 75, and the dichroic mirrors 80A and 80B can be changed according to specifications.

The light of the second LED array 75 passes through the interface of the dichroic mirror 80 1 time at the time of reflection, whereas the light of the first LED array 71 passes through the interface of the dichroic mirror 80 2 times. Further, although the light of the second LED array 75 is reflected by the dichroic mirror 80, since the film thickness of the dichroic mirror 80 is proportional to the reflected wavelength, the film thickness can be reduced when the wavelength of the reflected light is short, and the production becomes easy. Therefore, in the case of using the dichroic mirror 80, it is preferable to apply an LED array having a relatively long peak wavelength to the first LED array 71 and apply an LED array having a relatively short peak wavelength to the second LED array 75.

Specifically, the following two combinations (a) and (B) are preferable combinations of the peak wavelength of the first LED array 71 and the peak wavelength of the second LED array 75.

(A) Peak wavelength of the first LED array 71: 360-380 nm

Peak wavelength of the second LED array 75: 300 to 355nm

(B) Peak wavelength of the first LED array 71: 385 to 410nm

Peak wavelength of the second LED array 75: 360-380 nm

In general, exposure sensitivity of a color resist having an absorption peak wavelength band coincident with the i-line (365nm) was confirmed by an experiment in the case of exposure using an LED element having each peak wavelength, and as a result, the sensitivity differences shown in table 1 were obtained. Table 1 is based on 365 nm.

[ Table 1]

Wavelength [ n m]	330	340	365	380	386
						Exposure sensitivity ratio	3.1	2.5	1	0.6	0.25

As is clear from table 1, for example, since the exposure sensitivity of light having a wavelength of 330nm is 3 times higher than that of light having a wavelength of 365nm, the output is about 30%, and the performance equivalent to that of the 365nm LED element can be obtained. Therefore, by combining two types of LED elements in accordance with the absorption peak wavelength band of the resist, the exposure process can be made more efficient by shortening the exposure time.

For example, when the second LED element 76 is 365nm, which is the main wavelength, and the first LED element 72 is 385nm, which is the sub-wavelength, the long-wavelength (385nm) LED element has a higher output than the 365nm LED element, although the exposure sensitivity is lower, and the transmittance is higher as the wavelength is longer. Specifically, as shown in fig. 4, the transmittance of the 385nm LED elements arranged in the first LED array 71 is about 98%, and as shown in fig. 5, the reflectance of the 365nm LED elements arranged in the second LED array 75 is about 100%, and the total loss is about 2%. Fig. 4 is a graph showing the transmittance of the dichroic mirror 80 as an example, and fig. 5 is a graph showing the reflectance of the dichroic mirror 80 of fig. 4. Each graph shows the transmittance and reflectance when the light emitted from each LED element 72, 76 passes through the condensing lens and enters the dichroic mirrors 80A, 80B at angles θ 1, θ 2 (see fig. 3) ranging substantially from 42 ° to 48 ° with respect to the surfaces of the dichroic mirrors 80A, 80B, and θ 1, θ 2 are 42 °, 45 °, and 48 °.

By combining the two types of LED elements in this manner, the exposure time can be shortened. Further, as a combination of two kinds of LED elements, an LED element having a peak wavelength of 365nm and an LED element having a peak wavelength of 330nm can be used, and the exposure time can be shortened as the same output.

Further, by combining an LED element having a dominant wavelength and an LED element having a wavelength longer than the dominant wavelength, the pattern to be formed can be stabilized.

For example, when exposure is performed using only a single-wavelength LED element having a peak wavelength of 365nm, the pattern formed by the resist is weakly cured, and the pattern is likely to be peeled off in the developing step. Peeling is easily generated at the end of the pattern, caused by light leakage of the pattern through the mask and a polymerization initiator of the resist. In general, in order to suppress peeling, it is necessary to increase the exposure time or to adjust the processes before and after, but as in this example, by using LED elements having a wavelength of 385nm in combination, which have high transmittance with respect to the resist and easily reach the deep portion of the resist because of high output and long wavelength, pattern stabilization can be achieved.

(second embodiment)

Next, a light source device 70 according to a second embodiment will be described with reference to fig. 6. As shown in fig. 6, in the light source device 70 of the present embodiment, both end portions 83 of the two dichroic mirrors 80A and 80B are cut parallel to the optical axis direction L from the dichroic mirror 80 toward the fly-eye lens 65. Accordingly, since the dichroic films 81 of the 2 dichroic mirrors 80A and 80B are in contact with each other at the top of the V-shape, the dichroic mirrors 80A and 80B allow the light emitted from the first LED array 71 to uniformly transmit through the entire region in the width direction of the dichroic mirror 80 (the direction orthogonal to the optical axis direction L), and also allow the light emitted from the second LED array 75 to be reflected in a wide range, thereby improving efficiency.

In this case, the first LED array 71 and the second LED array 75 may be arranged so that the positions thereof with respect to the two dichroic mirrors 80A and 80B are reversed.

The other configurations and operations are the same as those of the first embodiment of the present invention.

(third embodiment)

Next, a light source device 70 according to a third embodiment will be described with reference to fig. 7. As shown in fig. 7, the present embodiment describes a method for fixing 2 pieces of dichroic mirrors 80A and 80B described in the above embodiment, using two dichroic mirror fixing frames 85.

The dichroic mirror fixing frame 85 has the following shape: 3 frames 85a, 85B, and 85c covering 3 sides out of 4 sides of the rectangular dichroic mirrors 80A and 80B are combined into a substantially "コ" shape, and the side surfaces of the dichroic mirrors 80A and 80B facing each other are opened. One side surfaces of the dichroic mirrors 80A and 80B are fitted into a groove 86 formed in a frame 85a of the dichroic mirror fixing frame 85 shaped like an コ, and the upper surfaces of the dichroic mirrors 80A and 80B are pressed toward the frame 85B by a pressing screw 87 provided in the frame 85c via a buffer 88 and fixed to the dichroic mirror fixing frame 85.

In fig. 7, in accordance with the second embodiment, the front end portions 83 of the 2 dichroic mirrors 80A and 80B that are abutted in the V-shape and the front end portion 85d of the dichroic mirror fixing frame 85 (frames 85B and 85c) to which the dichroic mirrors 80A and 80B are fixed are cut in parallel to the optical axis direction L from the dichroic mirror 80 toward the fly eye lens 65, and are abutted in close contact with each other without a gap, preferably adhered without a gap.

Further, the fly-eye-lens-side distal end portion 85d of the V-shaped dichroic mirror fixing frame 85 (frames 85b and 85c) is cut at right angles to the optical axis direction L from the dichroic mirror 80 toward the fly-eye lens 65, and forms planes that are coplanar with each other. This enables the 2 dichroic mirrors 80A and 80B to be further brought closer to the fly-eye lens 65 by the cut length of the dichroic mirror fixing frame 85, thereby improving efficiency and making the light source device 70 compact. In fig. 7(B) of the dichroic mirror fixing frame 85 (frames 85a, 85B, and 85c) supporting the dichroic mirrors 80A and 80B, the range outside the arrow is disposed outside the optical path of the exposure light, and the dichroic mirror fixing frame 85 does not become an obstacle to exposure.

As a modification of the present embodiment, as shown in fig. 8, the dichroic mirror fixing frame 85 may have grooves 86 formed in 3 frames 85a, 85B, and 85c, respectively, and the sides (3 sides) of the dichroic mirrors 80A and 80B may be fitted into the 3 grooves 86 and fixed by an adhesive. As in the case shown in fig. 7, the front end portions 83 of the 2 dichroic mirrors 80A and 80B and the front end portions 85d of the two dichroic mirror fixing frames 85 are in close contact with each other without a gap, and preferably are bonded to each other without a gap.

(fourth embodiment)

Next, a light source device 70 according to a fourth embodiment will be described with reference to fig. 9. As shown in fig. 9, in the present embodiment, two types of two second LED arrays 75A and 75B are arranged on a plane perpendicular to the optical axis direction L on the side of the V-shaped 2-piece dichroic mirrors 80A and 80B. The two second LED arrays 75A and 75A on the one hand and the two second LED arrays 75B and 75B on the other hand are alternately arranged at 90 ° intervals on the plane.

For example, the first LED array 71 uses the LED element 72 having a peak wavelength of 365nm, one of the second LED arrays 75A uses the LED element 76A having a peak wavelength of 385nm, and the other of the second LED arrays 75B uses the LED element 76B having a peak wavelength of 330 nm. In the case of using the first LED array 71 and one of the second LED arrays 75A and the case of using the first LED array 71 and the other of the second LED arrays 75B, two different dichroic mirrors 80 and 90 are switched to be used. Therefore, the dichroic mirrors 80 and 90 are detachably disposed in the mirror mounting portions, not shown, so as to be capable of changing the mounting postures.

The dichroic mirror 90 is composed of 2 dichroic mirrors 90A and 90B, similar to the dichroic mirror 80 described in embodiments 1 to 3. However, in the present embodiment, the dichroic mirrors 80 and 90 have different characteristics of reflecting the wavelength band of the characteristics in accordance with the two second LED elements 76A and 76B.

When the use of the second LED arrays 75A, 75B is switched, the dichroic mirror 80 when the first LED array 71 and one of the second LED arrays 75A are used and the dichroic mirror 90 when the first LED array 71 and the other of the second LED arrays 75B are used are arranged so that the arrangement directions of the dichroic mirrors 80A, 80B, 90A, 90B are orthogonal to each other on the plane.

Thus, when the light source device is of a specification in which exposure can be performed by switching between two types of second LED elements 76A and 76B, only the dichroic mirrors 80 and 90 need not be replaced, and the second LED arrays 75A and 75B need not be replaced, and replacement work of the electrical system and the cooling system in the case of replacing the second LED arrays 75A and 75B is not required.

As a modification of the present embodiment, when the peak wavelengths of the two types of second LED arrays 75A and 75B are the same, the dichroic mirror 80 may be configured to be rotatable. When the LED arrays 75A and 75B are used, the dichroic mirror 80 is rotated in the direction according to the used LED arrays 75A and 75B.

The present invention is not limited to the above embodiments, and modifications, improvements, and the like can be appropriately made.

For example, in the above-described embodiment, the light beams having different peak wavelengths are synthesized by dichroic mirrors, but the light synthesizing element of the present invention is not limited to this, and may be a dichroic prism.

As shown in fig. 10, the dichroic prism 180 is formed by joining 3 rectangular prisms 181, 182, and 183, which are materials having high transmittance such as glass and plastic. Each of the prisms 181, 182, and 183 has a substantially right isosceles triangle shape in side view, and a prism larger than the prisms 182 and 183 is used for the prism 181. The dichroic prism 180 has a rectangular shape in side view in which sides other than the hypotenuse of the prism 181 and the hypotenuses of the prisms 182 and 183 are bonded to each other via a dichroic film not shown. The interface 184 of the prisms 181 and 182 on which the dichroic films are disposed and the interface 185 of the prisms 181 and 183 are inclined at substantially 45 ° with respect to the optical axis direction L, and the interfaces 184 and 185 are formed so as to intersect at 90 °. Thus, the two dichroic films are arranged in a substantially V-shape so as to be in close contact with each other on the fly eye lens side.

The dichroic prism 180 can equalize the number of times that the light from the first LED array 71 and the second LED array 75 passes through the interfaces 181a, 182b, 183a, 183b, 184, and 185 (including the light incident surface and the light emitting surface). Further, by using the dichroic prism 180, a structure for closely attaching 2 dichroic mirrors is not necessary.

In the above embodiment, the dichroic mirrors arranged in a V-shape are used, and the light emitted from the two LED arrays is emitted toward the fly-eye lens 65 via the dichroic mirrors. On the other hand, as another optical device 70A of the present invention, as shown in fig. 11, it is also possible to include only 1 LED array 78 without dichroic mirrors 80A, 80B, and to dispose this LED array 78 directly opposite the fly eye lens 65.

In this case, the LED array 78 is configured by arranging the first LED element 72 and the second LED element 76 in a mixed manner. Therefore, of the light emitted from the LED array 78, the light of the first LED element 72 and the light of the second LED element 76 are mixed and emitted to the fly-eye lens 65.

The peak wavelength of the light emitted from the second LED element 76 coincides with the peak wavelength (photosensitive wavelength) sensitivity of the polymerization initiator of the photosensitive material, and is an arbitrary wavelength in the range of 300 to 355nm, and the peak wavelength of the light emitted from the first LED element 72 coincides with the partial sensitivity of the absorption sag of the polymerization initiator, and is an arbitrary wavelength in the range of 360 to 380 nm. Specifically, the peak wavelength of the light emitted from the second LED element 76 is set to 335nm, for example, and the peak wavelength of the light emitted from the first LED element 72 is set to 365nm, for example.

This makes it possible to efficiently expose the resist to light, and to eliminate the need for a light combining element such as a dichroic mirror for combining light, and to dispose the LED array 78 close to the fly-eye lens 65, thereby improving the efficiency. Further, the peak wavelength can be freely set in accordance with the sensitivity of the photosensitive material without the need to restrict the wavelength difference of light of the first and second LED elements 72 and 76 to 20nm or more.

As a further modification shown in fig. 12, the light source device 70B may be configured with 1 dichroic mirror 80 instead of 2 dichroic mirrors 80A and 80B arranged in a V-shape. In this case, the first LED array 71 having the plurality of first LED elements 72 and the second LED array 75 having the plurality of second LED elements 76 are arranged orthogonally, and the dichroic mirror 80 is arranged with being inclined at 45 ° with respect to the first LED array 71 and the second LED array 75.

Thus, the light emitted from the first LED array 71 passes through the dichroic mirror 80 and enters the fly eye lens 65, and the light emitted from the second LED array 75 is reflected by the dichroic mirror 80, combined with the light emitted from the first LED array 71, and enters the fly eye lens 65.

The color filter resist is prepared by mixing a polymerization initiator, a pigment, a polymerizable monomer, a polymer, and a solvent, and the following examples (1) to (10) are given as the polymerization initiator having an absorption peak in the range of 300 to 355 nm. Of these polymerization initiators, (9) Irgacure OXE01 and (10) Irgacure OXE02, which are highly sensitive, are preferable.

(1) Name: omnirad184 (registered trademark), produced by IGM Resins B.V. (1-hydroxycyclohexyl-phenyl ketone: 1-hydroxycyclohexyl-phenyl ketone).

[ chemical formula 1]

(2) Name: omnirad 1173 (registered trademark), produced by IGM Resins B.V. (2-hydroxy-2-methyl-1-phenylpropanone: 2-hydroxy-2-methyl-1-phenylpropanone).

[ chemical formula 2]

(3) Name: omnirad651 (registered trademark), produced by IGM Resins B.V. (2, 2-dimethoxy-2-phenylacetophenone: 2, 2-dimethoxy-2-phenylacetophenone).

[ chemical formula 3]

(4) Name: omnirad2959 (registered trademark), produced by IGM Resins B.V. (1- [4- (2-hydroxyethoxy) -phenyl ] -2-hydroxy-methylpropanone: 1- [4- (2-hydroxyethoxy) -phenyl ] -2-hydroxy-methylpropanone).

[ chemical formula 4]

(5) Name: omnirad127 (registered trademark), produced by IGM Resins b.v. (2-hydroxy-1- (4- (4- (2-hydroxy-2-methylpropionoyl) benzyl) phenyl) -2-methylproppan-1-one: 2-hydroxy-1- (4- (2-hydroxy-2-methylpropionoyl) benzyl) phenyl) -2-methylpropan-1-one).

[ chemical formula 5]

(6) Name: omnirad 369 (registered trade Mark), produced by IGM Resins B.V. (2-benzyl-2- (dimethyllamino) -4 '-morpholinone: 2-benzyl-2 (dimethylamino) -4' -morpholinebutylphenone).

[ chemical formula 6]

(7) Name: omnirad379EG (registered trademark), produced by IGM Resins b.v. (2-dimethylamino-2- (4-methyl-benzyl) -1- (4-morpholino-4-yl-phenyl) -butan-1-one: 2-dimethylamino-2- (4-methyl-benzyl) -1- (4-morpholin-4-yl-phenyl) -butan-1-one).

[ chemical formula 7]

(8) Name: omnirad MBF (registered trademark), manufactured by IGM Resins B.V. (Methylbenzoylformat: methyl benzoylformate).

[ chemical formula 8]

(9) Name: irgacure OXE01 (registered trademark) was produced by BASF ジャパン corporation (1,2-Octanedione,1- [4- (phenylthio) phenyl ] -,2- (o-benzoxyimide): 1,2-Octanedione,1- [4- (phenylthio) phenyl ] -,2- (benzoyloxime)).

[ chemical formula 9]

(10) Name: irgacure OXE02 (registered trademark) was produced by BASF ジャパン K.K. (ethanone, 1- [9-ethyl-6- (2-methylbenzonyl) -9H-carbazol-3-yl ] -,1- (O-acetyloxime: ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl ] -,1- (O-acetyloxime).

[ chemical formula 10]

In addition, the present application is based on the japanese patent application filed on 3/4/2019 (japanese patent application 2019-038939), the contents of which are incorporated herein by reference.