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 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 it onto a substrate using an imaging optical system. At this time, 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 carried out while changing the pattern image at each position on the substrate, thereby creating the desired pattern across the entire substrate.

[0003] Digital exposure systems using digital devices such as a digital mirror device (DMD) or spatial light modulator (SLM) perform the exposure process by projecting a 2D pattern image formed by the DMD onto a substrate through an optical system. Therefore, digital exposure systems using a DMD have the advantage of being able to expose a 2D pattern image at once, making them optimized for step-and-repeat exposure processes and widely used in 3D printers.

[0004] However, digital exposure systems using digital mirror devices (DMDs) expose a 2D pattern image in one go, making them unsuitable for scan-based exposure processes. The roll-to-roll exposure process is an exposure method for continuous production of flexible substrates, in which rolled flexible substrates are continuously exposed while being transported. However, because digital exposure systems using digital mirror devices are optimized for step-and-repeat exposure processes, they are difficult to apply to roll-to-roll exposure processes, in which rolls are continuously transported and scanned for exposure. Furthermore, because roll-to-roll exposure processes involve exposing rolled flexible substrates while they are being transported, it is necessary to minimize the deformation and vibration of the transporting rolls to improve exposure precision. Furthermore, the exposure process must be performed on the surface of a roll-transport drum, which minimizes roll vibration. Therefore, digital exposure systems using digital mirror devices, which project and expose 2D flat images, are difficult to apply to roll-to-roll exposure processes. Furthermore, because they expose a 2D pattern image in one go, they are difficult to adapt to curvatures in 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), which can cause significant warpage of the substrate. Summary of the Invention [Problem to be solved by the invention]

[0005] SUMMARY OF THE INVENTION 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, wherein the two-dimensional pattern image has 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.

[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 the 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 to compensate for light diffracted in a scanning direction of the substrate.

[0010] The diffraction compensation unit may be located between a plurality of projection lenses of the optical system.

[0011] The diffraction compensation unit may be installed between the plurality of projection lenses in correspondence with 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 around 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 device may include a plurality of pixel mirrors that rotate around 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] A digital exposure system according to an embodiment of the present invention forms a two-dimensional pattern image having a uniform image in the 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 applicable to a scan-type digital exposure process and therefore applicable to a roll-to-roll type digital exposure process.

[0017] Furthermore, since a pattern can be formed on a substrate by continuously scanning and exposing a one-dimensional pattern image, a digital exposure process can be applied to non-planar substrates. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a schematic perspective view of a digital exposure system according to an embodiment of the present invention; [Figure 2] 1 is a schematic front view of a digital exposure system according to one embodiment of the present invention; [Figure 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. [Figure 5] FIG. 10 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] FIG. 2 is a schematic side view of a digital exposure system according to another embodiment of the present invention. [Figure 8] 1 is a diagram illustrating a state in which the focusing direction of a two-dimensional pattern image and the 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] 10 is a diagram illustrating a state in which the focusing direction of a two-dimensional pattern image and the 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] 10 is a diagram illustrating a state in which the focusing direction of a two-dimensional pattern image of a digital exposure system and the pixel rotation axis of a digital mirror device are perpendicular to each other according to an embodiment of the present invention. [Figure 11] 10 is a diagram illustrating a state in which the focusing direction of a two-dimensional pattern image of a digital exposure system and the pixel rotation axis of a digital mirror device are parallel to each other according to another embodiment of the present invention. [Figure 12] 10 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 INVENTION

[0019] The present invention will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily implement various embodiments of the present invention. The present invention may be embodied in various different forms and is not limited to the examples 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 throughout the specification to refer to the same or similar components.

[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 one 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, etc. 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 process of forming a two-dimensional pattern image and modulating the two-dimensional pattern image into a one-dimensional pattern image using 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 can 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 the 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 the 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 focuses the two-dimensional pattern image (PI) in a direction (X) parallel to the scanning direction (X) of the substrate 10, and images it in a direction (Y) perpendicular to the scanning direction (X) of the substrate 10, thereby modulating it 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 uniform light intensity can be exposed onto 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 and changes 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] As described above, the digital exposure system according to one 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 substrate scanning direction and an image of a target pattern in a direction perpendicular to the substrate scanning direction, 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 movement speed of the substrate 10, thereby exposing a desired 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 line focus can be formed on the surface of a cylindrical drum in a roll-to-roll 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 can correct patterns more precisely for each scanning position and in real time, which makes it applicable to the exposure process of high-performance semiconductor packages such as wafer level packages (WLP) and panel level packages (PLP), which are prone to large deformation of the substrate.

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

[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, and therefore 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 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 dispersion of the light focus and the formation of multiple images. Therefore, the diffraction compensator 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 compensator 500 is not necessarily limited thereto, and 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 the 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 two-dimensional pattern image and the scanning direction of a substrate in a digital exposure system according to one embodiment of the present invention are parallel to each other, and FIG. 9 is a diagram illustrating a state in which the focusing direction of a two-dimensional pattern image and the 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.

[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, the focusing direction (FA) in which the two-dimensional pattern images (PI1, PI2) are focused and the 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 each of the first row one-dimensional pattern image (LI1) and the second row one-dimensional pattern image (LI2), it is difficult to expose a continuous target pattern.

[0048] However, in a digital exposure system according to another embodiment of the present invention, as shown in Figure 9, the digital mirror element 200 may be arranged so 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, the on and 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, so that a continuous target pattern can also be exposed.

[0049] Meanwhile, unlike the other embodiments shown in FIGS. 5 to 7, other embodiments are possible in which the digital mirror element is arranged so that the focusing direction in which the 2D 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 illustrating a state in which the focusing direction of a two-dimensional pattern image and the pixel rotation axis of a digital mirror element in a digital exposure system according to one embodiment of the present invention are perpendicular to each other, and FIG. 11 is a diagram illustrating a state in which the focusing direction of a two-dimensional pattern image and the pixel rotation axis of a digital mirror element in a digital exposure system according to another embodiment of the present invention 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 about a pixel rotation axis (RA). The digital mirror element 200 can form a two-dimensional pattern image (PI) by rotating the plurality of pixel mirrors 210 arranged in a matrix about the pixel rotation axis (RA) to reflect light.

[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, steps may occur between the plurality of pixel mirrors 210, which may reduce the clarity of the one-dimensional pattern image (LI).

[0055] However, as shown in Figure 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 steps are generated between the plurality of pixel mirrors 210, and therefore the clarity of the one-dimensional pattern image (LI) can be improved.

[0056] Furthermore, the digital exposure system according to another embodiment of the present invention includes a diffraction compensation unit 500, which blocks high-order diffracted light 2 (0th order or higher) to form a clear one-dimensional linear image. At this time, since the diffraction compensation unit 500 blocks high-order diffracted light 2 from some of the plurality of pixel mirrors 210, only the pixel mirrors 210 located in the central region (UA) of the plurality of pixel mirrors 210 can be used. Therefore, by emitting only the light corresponding to the pixel mirrors 210 located in the central region (UA) 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] A digital exposure system according to another embodiment of the present invention will now 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 and the 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, 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 and off pixels in adjacent one-dimensional pattern images (LI) are connected to each other without being clearly separated from each other, and therefore 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 which case the step between the plurality of pixel mirrors 210 is minimized, thereby minimizing the reduction in clarity of the one-dimensional pattern image (LI).

[0063] Although the present invention has been described above through the 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 including a plurality of projection lenses for modulating the two-dimensional pattern image into a one-dimensional pattern image, and a cylindrical lens positioned between the projection lenses and the substrate; 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, the two-dimensional pattern image has a uniform image in a direction parallel 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; A digital exposure system in which the two-dimensional pattern image is 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.

2. 2. The digital exposure system according to claim 1, further comprising a diffraction compensation unit disposed in the optical system for compensating for light diffracted in a scanning direction of the substrate.

3. 3. The digital exposure system according to claim 2, wherein the diffraction compensation unit is located between a plurality of projection lenses of the optical system.

4. 4. The digital exposure system according to claim 3, wherein the diffraction compensation unit is installed corresponding to a focusing point where the light is focused among the plurality of projection lenses.

5. The digital exposure system according to claim 2 , wherein the diffraction compensation unit includes a slit or an aperture.

6. 3. The digital exposure system of claim 2, 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.

7. A focusing direction in which the two-dimensional pattern image is focused and a scanning direction of the substrate are parallel to each other; 3. The digital exposure system of claim 2, wherein the digital mirror element includes a plurality of pixel mirrors that rotate around a pixel rotation axis, and a focusing direction in which the two-dimensional pattern image is focused and the pixel rotation axis are parallel to each other.

8. 7. The digital exposure system of claim 6, wherein the digital mirror element includes a plurality of pixel mirrors that rotate around a pixel rotation axis, and a focusing direction in which the two-dimensional pattern image is focused and the pixel rotation axis have the first tilt angle.

Images