Digital Exposure System

Abstract

A digital exposure system according to one embodiment of the present invention includes a light source that irradiates light onto a substrate; a digital mirror element that selectively transmits light emitted from the light source to form a two-dimensional pattern image; an optical system that modulates the two-dimensional pattern image into a one-dimensional pattern image; and a substrate scanner that adjusts the position of the substrate and continuously scans and exposes the one-dimensional pattern image onto a photosensitive film on the substrate, the two-dimensional pattern image having a uniform image in a direction horizontal to a scanning direction of the substrate and an image of a target pattern in a direction perpendicular to the scanning direction of the substrate.

Description

[Technical field]

[0001] The present invention relates to a digital exposure system, and more particularly to a digital exposure system that utilizes a digital mirror element. [Background technology]

[0002] Generally, the digital exposure process is a type of photolithography process, and is a technology that creates a desired pattern on a photoresist without a mask. In this digital exposure process, a digital device reproduces a pattern image and projects the pattern image onto a substrate using an imaging optical system, at which point the photoresist coated on the substrate is exposed to light to create a pattern. Since the size of the pattern image is smaller than the size of the substrate, the exposure process is performed while changing the pattern image for each position on the substrate, and the desired pattern is created over the entire substrate.

[0003] Digital exposure systems using digital devices such as digital mirror devices (DMD) or spatial light modulators (SLM) perform exposure processes by projecting a two-dimensional pattern image formed by a digital mirror device (DMD) onto a substrate through an optical system. Therefore, digital exposure systems using digital mirror devices (DMD) are optimized for step-and-repeat exposure processes due to their advantage of being able to expose a two-dimensional pattern image at once, and are actively used in 3D printers, etc.

[0004] However, a digital exposure system using a digital mirror device (DMD) is not suitable for a scan-type exposure process because it exposes a two-dimensional pattern image at once. The roll-to-roll exposure process is an exposure method for continuous production of flexible substrates, in which a rolled flexible substrate is continuously exposed while being transported. However, since a digital exposure system using a digital mirror device is optimized for a step-and-repeat exposure process, it is difficult to apply it to a roll-to-roll exposure process in which a roll is continuously transported and scan-exposed. In addition, since the roll-to-roll exposure process is a method in which a roll-shaped flexible substrate is exposed while being transported, it is necessary to minimize the deformation and vibration of the transported roll to improve exposure precision, and the exposure process must be performed on the surface of the roll transport drum where the vibration of the roll is minimized. Therefore, a digital exposure system using a digital mirror device that projects and exposes a two-dimensional flat image is difficult to apply to a roll-to-roll exposure process. In addition, since a two-dimensional pattern image is exposed at once, it is difficult to deal with the curvature of the substrate surface. For these reasons, it is difficult to apply a digital exposure system using a digital mirror device (DMD) to the exposure process of high-performance semiconductor packages such as wafer level packages (WLP) or panel level packages (PLP), where warpage of the substrate can occur significantly. Summary of the Invention [Problem to be solved by the invention]

[0005] SUMMARY OF THE PRESENTLY PREFERRED EMBODIMENTS The present invention has been made to solve the problems of the background art described above, and an object of the present invention is to provide a digital exposure system capable of performing digital exposure on a non-planar substrate using a scanning method.

[0006] A digital exposure system according to one embodiment of the present invention includes a light source that irradiates light onto a substrate; a digital mirror element that selectively transmits light emitted from the light source to form a two-dimensional pattern image; an optical system that modulates the two-dimensional pattern image into a one-dimensional pattern image; and a substrate scanner that adjusts the position of the substrate and continuously scans and exposes the one-dimensional pattern image onto a photosensitive film on the substrate, the two-dimensional pattern image having a uniform image in a direction horizontal to a scanning direction of the substrate and an image of a target pattern in a direction perpendicular to the scanning direction of the substrate.

[0007] The optical system may also include a plurality of projection lenses, and a cylindrical lens positioned between the projection lenses and the substrate.

[0008] Also, the two-dimensional pattern image may be focused in a direction parallel to a scanning direction of the substrate, imaged in a direction perpendicular to the scanning direction of the substrate, and modulated into the one-dimensional pattern image.

[0009] The optical system may further include a diffraction compensator disposed in the optical system and configured to compensate for light diffracted in a scanning direction of the substrate.

[0010] Also, the diffraction compensation section may be located between a plurality of projection lenses of the optical system.

[0011] The diffraction compensation unit may be disposed between the plurality of projection lenses in a position corresponding to a focusing point where the light is focused.

[0012] The diffraction compensation portion may include a slit or an aperture.

[0013] Also, a focusing direction in which the two-dimensional pattern image is focused and a scanning direction of the substrate may have a first tilt angle greater than 0 degrees and less than 45 degrees.

[0014] The digital mirror device may include a plurality of pixel mirrors that rotate based on a pixel rotation axis, and a focusing direction in which the two-dimensional pattern image is focused and the pixel rotation axis may be parallel to each other.

[0015] The digital mirror element may include a plurality of pixel mirrors that rotate based on a pixel rotation axis, and a focusing direction in which the two-dimensional pattern image is focused and the pixel rotation axis may have the first tilt angle.

[0016] The digital exposure system according to an embodiment of the present invention forms a two-dimensional pattern image having a uniform image in a substrate scanning direction and an image of a target pattern in a direction perpendicular to the substrate scanning direction using a digital mirror element, modulates the two-dimensional pattern image into a one-dimensional pattern image using an optical system, and continuously scans and exposes the one-dimensional pattern image, thereby improving productivity by being applied to a scan-type digital exposure process. Therefore, the system can be applied to a roll-to-roll type digital exposure process.

[0017] In addition, since a one-dimensional pattern image can be continuously scanned and exposed to form a pattern on a substrate, a digital exposure process can be applied to non-planar substrates. [Brief description of the drawings]

[0018] [Figure 1] 1 is a schematic perspective view of a digital exposure system according to one embodiment of the present invention; [Diagram 2] 1 is a schematic front view of a digital exposure system according to one embodiment of the present invention; [Diagram 3] 1 is a schematic side view of a digital exposure system according to one embodiment of the present invention. [Figure 4]4 is a diagram illustrating a state in which a two-dimensional pattern image is formed and the two-dimensional pattern image is modulated into a one-dimensional pattern image by a digital exposure system according to an embodiment of the present invention. [Diagram 5] FIG. 2 is a schematic perspective view of a digital exposure system according to another embodiment of the present invention. [Figure 6] FIG. 2 is a schematic front view of a digital exposure system according to another embodiment of the present invention. [Figure 7] 2 is a schematic side view of a digital exposure system according to another embodiment of the present invention. [Figure 8] 4 is a diagram illustrating a state in which a focusing direction of a two-dimensional pattern image and a scanning direction of a substrate are parallel to each other in a digital exposure system according to an embodiment of the present invention. [Figure 9] 11 is a diagram illustrating a state in which a focusing direction of a two-dimensional pattern image and a scanning direction of a substrate in a digital exposure system according to another embodiment of the present invention have a first tilt angle greater than 0 degrees and less than 45 degrees. [Figure 10] 4 is a diagram illustrating a state in which a focusing direction of a two-dimensional pattern image of a digital exposure system and a pixel rotation axis of a digital mirror device are perpendicular to each other according to an embodiment of the present invention. [Figure 11] 11 is a diagram illustrating a state in which a focusing direction of a two-dimensional pattern image of a digital exposure system and a pixel rotation axis of a digital mirror device are parallel to each other according to another embodiment of the present invention. [Figure 12] 11 is a diagram illustrating a state in which the focusing direction of a two-dimensional pattern image of a digital exposure system according to another embodiment of the present invention and the scanning direction of a substrate have a first tilt angle greater than 0 degrees and less than 45 degrees, and the focusing direction of the two-dimensional pattern image and the pixel rotation axis of a digital mirror element have a first tilt angle. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily carry out the present invention. The present invention may be embodied in various different forms, and is not limited to the embodiments described herein.

[0020] In order to clearly describe the present invention, parts that are not relevant to the description will be omitted, and the same reference numerals will be used to refer to the same or similar components throughout the specification.

[0021] Next, a digital exposure system according to an embodiment of the present invention will be described in detail with reference to FIGS.

[0022] FIG. 1 is a schematic perspective view of a digital exposure system according to one embodiment of the present invention, FIG. 2 is a schematic front view of a digital exposure system according to one embodiment of the present invention, and FIG. 3 is a schematic side view of a digital exposure system according to one embodiment of the present invention.

[0023] As shown in FIGS. 1 to 3, a digital exposure system according to an embodiment of the present invention includes a light source 100, a digital mirror element 200, an optical system 300, and a substrate scanner 400.

[0024] The light source 100 can irradiate light 1 onto the photosensitive film 20 on the substrate 10. The light source 100 can include any one selected from an LED, a lamp, a laser, and the like. The light 1 irradiated from the light source 100 can have various wavelengths such as 365 nm, 435 nm, and 405 nm. The light 1 emitted from the light source 100 can be incident on the digital mirror element 200 via the reflective member 30.

[0025] The digital mirror device 200 can selectively transmit light 1 emitted from the light source 100 to form a two-dimensional pattern image (PI).

[0026] FIG. 4 is a diagram illustrating a state in which a two-dimensional pattern image is formed and the two-dimensional pattern image is modulated into a one-dimensional pattern image by a digital exposure system according to an embodiment of the present invention.

[0027] As shown in FIG. 4, the two-dimensional pattern image (PI) generated by the digital mirror element 200 may have a uniform image in a direction (X) parallel to the scanning direction (X) of the substrate 10, and an image of the target pattern (TP) in a direction (Y) perpendicular to the scanning direction (X) of the substrate 10.

[0028] The optical system 300 can modulate the two-dimensional pattern image (PI) generated by the digital mirror element 200 into a one-dimensional pattern image (LI). The one-dimensional pattern image (LI) can have an image of the target pattern (TP) only in a direction (Y) perpendicular to the scanning direction (X) of the substrate 10.

[0029] The optical system 300 may include a plurality of projection lenses 310 and a cylindrical lens 320 located on an optical path between the projection lenses 310 and the substrate 10. The cylindrical lens 320 is an asymmetric lens, and the optical system 300 including the asymmetric lens may focus the two-dimensional pattern image (PI) in a direction (X) parallel to the scanning direction (X) of the substrate 10, image the two-dimensional pattern image (PI) in a direction (Y) perpendicular to the scanning direction (X) of the substrate 10, and modulate the image into a one-dimensional pattern image (LI). Here, the focusing direction (FA) in which the two-dimensional pattern image (PI) is focused may be parallel to the scanning direction (X) of the substrate 10. Therefore, the one-dimensional pattern image (LI) having a uniform light intensity may be exposed on the photosensitive film 20 on the substrate 10.

[0030] The substrate scanner 400 adjusts the position of the substrate 10 to continuously scan and expose the one-dimensional pattern image (LI) onto the photosensitive film 20 on the substrate 10. At this time, the digital mirror device 200 synchronizes the one-dimensional pattern image (LI) with the moving speed of the substrate 10 to change the speed to the same as the moving speed of the substrate 10, thereby exposing the target pattern (TP) onto the photosensitive film 20 of the substrate 10.

[0031] In this way, the digital exposure system according to an embodiment of the present invention uses a digital mirror element to form a two-dimensional pattern image having a uniform image in a direction parallel to the scanning direction of the substrate and an image of a target pattern in a direction perpendicular to the scanning direction of the substrate, modulates the two-dimensional pattern image into a one-dimensional pattern image (LI) using an optical system, and changes the one-dimensional pattern image (LI) at the same speed as the moving speed of the substrate 10, thereby exposing a target pattern (TP) on the photosensitive film 20 of the substrate 10. Therefore, since the one-dimensional pattern image (LI) is continuously scanned and exposed on the photosensitive film 20 of the substrate 10, productivity can be improved by applying it to a scan-type digital exposure process. Therefore, since a linear focus can be formed on the surface of a cylindrical drum in a roll-to-roll type digital exposure process, it can be applied to a roll-to-roll exposure process that requires exposure on a curved surface.

[0032] In addition, since it is a linear scanning exposure process rather than a step and repeat exposure process, it is possible to correct the pattern in real time by correcting each scanning position more precisely. Therefore, it can be applied to the exposure process of high-performance semiconductor packages such as wafer level package (WLP) or panel level package (PLP) where the deformation of the substrate is large.

[0033] Meanwhile, unlike the above embodiment, another embodiment may be possible in which a diffraction compensator capable of compensating for light diffracted in the scanning direction of the substrate is added.

[0034] A digital exposure system according to another embodiment of the present invention will be described in detail below with reference to FIGS.

[0035] FIG. 5 is a schematic perspective view of a digital exposure system according to another embodiment of the present invention, FIG. 6 is a schematic front view of a digital exposure system according to another embodiment of the present invention, and FIG. 7 is a schematic side view of a digital exposure system according to another embodiment of the present invention.

[0036] The other embodiment shown in FIGS. 5 to 7 is substantially the same as the embodiment shown in FIGS. 1 to 4 except for the diffraction compensation portion, so a repeated description will be omitted.

[0037] As shown in FIGS. 5 to 7, a digital exposure system according to another embodiment of the present invention includes a light source 100, a digital mirror element 200, an optical system 300, a substrate scanner 400, and a diffraction compensation unit 500.

[0038] The diffraction compensation unit 500 is installed in the optical system 300 and can compensate for the light diffracted in the scanning direction (X) of the substrate 10 .

[0039] When the light source 100 is a coherent light source such as a laser, the light 1 passing through the digital mirror element is diffracted to generate diffracted light 2, which may result in the formation of multiple images due to the dispersion of the light focus. Therefore, the diffraction compensation unit 500 can be used to block high-order diffracted light 2 (0th order or higher) to form a clear one-dimensional linear image.

[0040] The diffraction compensation unit 500 may be located between the plurality of projection lenses 310. The diffraction compensation unit 500 may be installed between the plurality of projection lenses 310 in correspondence with a focusing point (FP) where the light 1 is focused.

[0041] The diffraction compensation unit 500 may include a slit extending in a direction (Y) perpendicular to the scanning direction (X) of the substrate 10. Therefore, it is possible to form a clear one-dimensional linear image by blocking high-order diffracted light diffracted in the scanning direction (X) of the substrate 10.

[0042] However, the diffraction compensation unit 500 is not necessarily limited thereto, and the diffraction compensation unit 500 may include an iris. The iris can block not only high-order diffracted light diffracted in the scanning direction (X) of the substrate 10, but also high-order diffracted light diffracted in a direction (Y) perpendicular to the scanning direction (X) of the substrate 10.

[0043] Meanwhile, in the above embodiment, the digital mirror element is arranged so that the focusing direction of the two-dimensional pattern image and the scanning direction of the substrate are parallel to each other, but other embodiments are also possible in which the digital mirror element is arranged so that the focusing direction of the two-dimensional pattern image and the scanning direction of the substrate have a predetermined inclination angle.

[0044] A digital exposure system according to another embodiment of the present invention will now be described in detail with reference to FIGS.

[0045] FIG. 8 is a diagram illustrating a state in which the focusing direction of a 2D pattern image of a digital exposure system according to one embodiment of the present invention and the scanning direction of a substrate are parallel to each other, and FIG. 9 is a diagram illustrating a state in which the focusing direction of a 2D pattern image of a digital exposure system according to another embodiment of the present invention and the scanning direction of a substrate have a first tilt angle greater than 0 degrees and less than 45 degrees.

[0046] The other embodiment shown in FIG. 9 is substantially the same as the embodiment shown in FIGS. 1 to 4 and 8 except for the arrangement direction of the digital mirror elements, and a repeated description will be omitted.

[0047] 8, in a digital exposure system according to an embodiment of the present invention, a focusing direction (FA) in which the two-dimensional pattern images (PI1, PI2) are focused and a scanning direction (X) of the substrate 10 may be parallel to each other. In this case, since the lit pixels and the unlit pixels are clearly separated from each other in the first row of the one-dimensional pattern image (LI1) and the second row of the one-dimensional pattern image (LI2), it is difficult to expose a continuous target pattern.

[0048] However, as shown in Fig. 9, in a digital exposure system according to another embodiment of the present invention, the digital mirror element 200 may be arranged such that the focusing direction (FA) in which the two-dimensional pattern images (PI1, PI2) are focused and the scanning direction (X) of the substrate 10 have a first tilt angle (q1) greater than 0 degrees and less than 45 degrees. In this case, since the on pixels and the off pixels in the first row of the one-dimensional pattern image (LI1) and the second row of the one-dimensional pattern image (LI2) are connected to each other without being clearly separated from each other, a continuous target pattern can also be exposed.

[0049] Meanwhile, unlike the other embodiments shown in Figures 5 to 7, other embodiments are also possible in which the digital mirror element is arranged so that the focusing direction in which the two-dimensional pattern image is focused and the pixel rotation axis of the digital mirror element are parallel to each other.

[0050] A digital exposure system according to another embodiment of the present invention will now be described in detail with reference to FIGS.

[0051] FIG. 10 is a diagram explaining a state in which the focusing direction of a two-dimensional pattern image of a digital exposure system according to one embodiment of the present invention and the pixel rotation axis of a digital mirror element are perpendicular to each other, and FIG. 11 is a diagram explaining a state in which the focusing direction of a two-dimensional pattern image of a digital exposure system according to another embodiment of the present invention and the pixel rotation axis of a digital mirror element are parallel to each other.

[0052] The other embodiment shown in FIG. 11 is substantially the same as the other embodiments shown in FIGS. 5 to 7 except for the arrangement direction of the digital mirror elements, and a repeated description will be omitted.

[0053] 10, a digital mirror element 200 of a digital exposure system according to an embodiment of the present invention may include a plurality of pixel mirrors 210 that rotate around a pixel rotation axis (RA). The digital mirror element 200 may form a two-dimensional pattern image (PI) by reflecting light by rotating the plurality of pixel mirrors 210 arranged in a matrix around the pixel rotation axis (RA).

[0054] In this case, when the focusing direction (FA) of the two-dimensional pattern image (PI) and the scanning direction (X) of the substrate 10 are parallel to each other, the focusing direction (FA) of the two-dimensional pattern image (PI) and the pixel rotation axis (RA) may have a second tilt angle (q2) with respect to each other depending on the arrangement direction of the digital mirror device 200 and the substrate 10. In this case, a step may be generated between the plurality of pixel mirrors 210, and the clarity of the one-dimensional pattern image (LI) may be reduced.

[0055] However, as shown in Fig. 11, when the focusing direction (FA) of the two-dimensional pattern image (PI) of the digital exposure system according to another embodiment of the present invention and the scanning direction (X) of the substrate 10 are parallel to each other, the focusing direction (FA) of the two-dimensional pattern image (PI) and the pixel rotation axis (RA) can be parallel to each other. In this case, no step is generated between the plurality of pixel mirrors 210, so the clarity of the one-dimensional pattern image (LI) can be improved.

[0056] In addition, the digital exposure system according to another embodiment of the present invention includes the diffraction compensation unit 500, and thus can form a clear one-dimensional linear image by blocking high-order diffracted light 2 of 0th order or higher. At this time, since the diffraction compensation unit 500 blocks high-order diffracted light 2 from some of the pixel mirrors 210, only the pixel mirrors 210 located in the central area (UA) among the pixel mirrors 210 can be used. Therefore, by emitting only light corresponding to the pixel mirrors 210 located in the central area (UA) among the light emitted from the light source 100, the exposure energy used can be minimized.

[0057] Meanwhile, unlike the other embodiment shown in FIG. 11, another embodiment is also possible in which the focusing direction of the two-dimensional pattern image and the scanning direction of the substrate have a first tilt angle greater than 0 degrees and less than 45 degrees, and the digital mirror element is arranged so that the focusing direction in which the two-dimensional pattern image is focused and the pixel rotation axis of the digital mirror element have a first tilt angle.

[0058] Hereinafter, a digital exposure system according to another embodiment of the present invention will be described in detail with reference to FIG.

[0059] FIG. 12 is a diagram illustrating a state in which the focusing direction of a two-dimensional pattern image of a digital exposure system according to another embodiment of the present invention and the scanning direction of a substrate have a first tilt angle greater than 0 degrees and less than 45 degrees, and the focusing direction of the two-dimensional pattern image and the pixel rotation axis of a digital mirror element have a first tilt angle.

[0060] The other embodiment shown in FIG. 12 is substantially the same as the other embodiment shown in FIG. 11 except for the arrangement direction of the digital mirror elements, and a repeated description will be omitted.

[0061] As shown in FIG. 12, since the focusing direction (FA) of the two-dimensional pattern image (PI) of the digital exposure system according to one embodiment of the present invention and the scanning direction (X) of the substrate 10 have a first tilt angle (q1) greater than 0 degrees and less than 45 degrees, the on pixels and off pixels in adjacent one-dimensional pattern images (LI) are connected to each other without being clearly separated from each other, so that continuous target patterns can also be exposed.

[0062] In addition, the focusing direction (FA) of the two-dimensional pattern image (PI) and the pixel rotation axis (RA) of the digital mirror element may have a first tilt angle (q1). In this case, the step between the plurality of pixel mirrors 210 is minimized, so that the decrease in the clarity of the one-dimensional pattern image (LI) is minimized.

[0063] Although the present invention has been described above through preferred embodiments, it will be readily understood by those skilled in the art to which the present invention pertains that the present invention is not limited thereto, and various modifications and variations are possible without departing from the concept and scope of the claims set forth below. [Explanation of symbols]

[0064] 100 light sources 200 Digital Mirror Element 210 pixel mirror 300 Optical system 400 PCB Scanner 500 Diffraction compensation section

Claims

1. a light source for irradiating the substrate with light; a digital mirror element that selectively transmits light emitted from the light source to form a two-dimensional pattern image; an optical system for modulating the two-dimensional pattern image into a one-dimensional pattern image; a substrate scanner for adjusting the position of the substrate and continuously scanning and exposing the one-dimensional pattern image onto the photosensitive film on the substrate; Including, A digital exposure system, wherein the two-dimensional pattern image has a uniform image in a direction parallel to a scanning direction of the substrate, and has an image of a target pattern in a direction perpendicular to the scanning direction of the substrate.

2. The optical system includes: Multiple projection lenses, and A cylindrical lens located between the projection lens and the substrate.

2. The digital exposure system of claim 1 .

3. The two-dimensional pattern image is The substrate is focused in a direction parallel to the scanning direction of the substrate, 3. The digital exposure system of claim 2, wherein the substrate is imaged in a direction perpendicular to a scanning direction and modulated into the one-dimensional pattern image.

4. The digital exposure system according to claim 3 , further comprising a diffraction compensation unit disposed in the optical system and configured to compensate for light diffracted in a scanning direction of the substrate.

5. The digital exposure system of claim 4 , wherein the diffraction compensation unit is located between a plurality of projection lenses of the optical system.

6. The digital exposure system according to claim 5 , wherein the diffraction compensation unit is disposed between the plurality of projection lenses in a position corresponding to a focusing point where the light is focused.

7. The digital exposure system according to claim 4 , wherein the diffraction compensation section includes a slit or an aperture.

8. 5. The digital exposure system of claim 4, wherein a focusing direction in which the two-dimensional pattern image is focused and a scanning direction of the substrate have a first tilt angle greater than 0 degrees and less than 45 degrees.

9. The digital mirror element includes a plurality of pixel mirrors that rotate about a pixel rotation axis; 9. The digital exposure system of claim 8, wherein a focusing direction in which the two-dimensional pattern image is focused and the pixel rotation axis are parallel to each other.

10. The digital mirror element includes a plurality of pixel mirrors that rotate about a pixel rotation axis; 9. The digital exposure system of claim 8, wherein a focusing direction in which the two-dimensional pattern image is focused and the pixel rotation axis have the first tilt angle.

Images