WO2008102995A1

WO2008102995A1 - Optical lithography device and manufacturing method for optical head thereof

Info

Publication number: WO2008102995A1
Application number: PCT/KR2008/001018
Authority: WO
Inventors: Shinill Kang; Ji Seok Lim
Original assignee: Industry-Academic Cooperation Foundation, Yonsei University
Priority date: 2007-02-22
Filing date: 2008-02-21
Publication date: 2008-08-28
Also published as: KR100964285B1; KR20080078565A

Abstract

An optical lithography device and a manufacturing method of an optical head thereof are provided. The optical lithography device includes a collimated light- supplying unit, which provides collimated light, an optical head, which divides the collimated light toward a plurality of regions, selectively allows the divided lights to pass through the respective regions, and condenses the lights passing through the respective regions, and a substrate-driving unit, which drives a substrate to be patterned by the lights irradiated from the optical head. The optical lithography device can be miniaturized thanks to the simplification of the structure thereof, the manufacturing cost is reduced, and the alignment error of the optical axis of the microlens array is minimized.

Description

OPTICAL LITHOGRAPHY DEVICE AND MANUFACTURING METHOD FOR OPTICAL HEAD THEREOF

Technical Field

[1] The present invention relates, in general, to an optical lithography device which can be miniaturized and reduce manufacturing cost, and a manufacturing method for an optical head thereof. Background Art

[2] Generally, optical lithography device are a device which is used in some fields, such as a flat panel display device, a circuit board, an integrated circuit device and the like, so as to form patterns by irradiation of light onto a resist film applied on a substrate.

[3] Presently, a flat panel display device has been widely used in the display industry because diverse products are provided and the flat panel display device can realize a large screen. Accordingly, the existing optical lithography process essentially needs diverse kinds of large-area masks.

[4] However, in order to manufacture the diverse kinds of large-area masks, it is required to overcome problems such as manufacturing cost and time.

[5] To this end, a maskless lithography device was proposed, which does not require a mask by using a spatial light modulator and a microlens array.

[6] The maskless lithography device was disclosed in Korean Patent Laid-Open

Publication No. 10-2004-0101066.

[7] In the lithography device, disclosed in Korean Patent Laid-Open Publication No.

10-2004-0101066, as shown in FIG. 1, radiation beam, generated by a light source LA, is transformed into collimated light while passing through a beam expander Ex and a collimator IL. The collimated light passes through a microlens array 11 to be divided into parallel optical probes mapped one-to-one to respective regions of a spatial light modulator 12. Then, the parallel optical probes are condensed while passing through a projection optical system 13. A substrate (wafer) W to be patterned and a substrate table WT for driving the substrate W are arranged such that the substrate W is disposed at a focus position of the projection optical system 13, and the substrate W is patterned by the condensed lights.

[8] The maskless lithography device has advantages in that the manufacturing cost of a mask is reduced, and that it can rapidly cope with change of the shape of a pattern. The plurality of optical probes can advantageously increase process efficiency compared to a single optical probe. Furthermore, because it adopts a step-and-repeat method or a step-and-scan method, a large-area patterning is easily obtained. [9] However, the above lithography device of the prior art has a problem that, since the structure thereof is very complicated, it is difficult and expensive to manufacture the lithography device. [10] Further, because of a long optical path and the structure that the lens array consists of a plurality of layers, optical efficiency and a beam spot characteristic at a focus point of the projection optical system deteriorate. [11] Still further, the lithography device consisting of the collimator, the spatial light modulator, the lens array, and the projection optical system, has a problem that alignment error of an optical axis increases. The lithography device has a complicated structure including a plurality of layers of optical elements, which makes it difficult to miniaturize the device.

Disclosure of Invention

Technical Problem [12] Accordingly, the present invention has been made keeping in mind the above problems occurring in the related art, and an object of the present invention is to propose an optical lithography device which can be miniaturized by simplifying the structure thereof and thus reduce its manufacturing cost, and a manufacturing method for an optical head thereof. [13] Another object is to propose an optical lithography device which can minimize the alignment error of an optical axis of a microlens array consisting of a plurality of layers, and a manufacturing method for an optical head thereof.

Technical Solution

[14] In order to achieve the above objects, according to one aspect of the present invention, there is provided an optical lithography device including: a collimated light- supplying unit, which provides collimated light, an optical head, which divides the collimated light toward a plurality of regions, selectively allows the divided lights to pass through the respective regions, and condenses the lights passing through the respective regions; and a substrate-driving unit, which drives a substrate to be patterned by the lights irradiated from the optical head.

[15] In a first embodiment of the invention, the optical head includes: a spatial light modulator, which has a plurality of the regions, and controls the respective regions to selectively allow the lights to pass; a first microlens array, which is disposed over the spatial light modulator to divide and refract the collimated light such that the divided lights are mapped to the respective regions; and a second microlens array, which is disposed under the spatial light modulator to condense the lights passing through the respective regions.

[16] In a second embodiment of the invention, the optical head includes: a spatial light modulator, which has a plurality of the regions, and controls the respective regions to selectively allow the lights to pass; a first microlens array, which is disposed over the spatial light modulator to divide and refract the collimated light such that the divided lights are mapped to the respective regions; a second microlens array, which is disposed under the spatial light modulator to condense the lights passing through the respective regions; and an anti-reflection coating layer, which is provided in at least one of positions between the spatial light modulator and the first microlens array and between the spatial light modulator and the second microlens array.

[17] In a third embodiment of the invention, the optical head includes: a spatial light modulator, which has a plurality of the regions, and controls the respective regions to selectively allow the lights to pass; a first microlens array, which is disposed over the spatial light modulator to divide and refract the collimated light such that the divided lights are mapped one-to-one to the respective regions; a second microlens array, which is disposed under the spatial light modulator to collimate the lights passing through the respective regions; and a third microlens array, which is disposed under the second microlens array to condense the lights.

[18] According to another aspect of the present invention, there is provided a manufacturing method of an optical head for an optical lithography device, the method including the steps of: applying a first polymer onto a surface of an upper glass substrate of a spatial light modulator; forming a first microlens array by pressing a first mold member having a lens pattern thereon against the first polymer and curing the first polymer; applying a second polymer onto a surface of a lower glass substrate of the spatial light modulator; forming a second microlens array by pressing a second mold member having a lens pattern thereon against the second polymer and curing the second polymer; and separating the first and second mold members from the spatial light modulator.

Advantageous Effects

[19] According to the present invention, the optical lithography device of the invention can be advantageously miniaturized thanks to the simplification of the structure thereof, and the manufacturing cost can also be reduced. [20] Further, provided is the advantage of minimizing the alignment error of the optical axis of the microlens array consisting of the plurality of layers.

Brief Description of the Drawings [21] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description when taken in conjunction with the accompanying drawings, in which: [22] FIG. 1 is a view illustrating the construction of an optical lithography device according to the prior art; [23] FIG. 2 is a view illustrating the construction of an optical lithography device according to a first embodiment of the present invention; [24] FIGS. 3 to 7 are process views illustrating manufacturing procedures of an optical head for the optical lithography device according to the first embodiment of the invention; [25] FIG. 8 is a view illustrating the construction of an optical lithography device according to a second embodiment of the present invention; and [26] FIG. 9 is a view illustrating the construction of an optical lithography device according to a third embodiment of the present invention.

Best Mode for Carrying Out the Invention [27] Reference will now be made in greater detail to a preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings and the description to refer to the same or like parts. [28] FIG. 2 is a view illustrating the construction of an optical lithography device according to an embodiment of the present invention. [29] The optical lithography device includes a collimated light-supplying unit 100, an optical head 200 condensing lights provided from the collimated light- supplying unit

100, and a substrate-driving unit 300 driving a substrate 310. [30] The collimated light-supplying unit 100 includes a light source 110 generating a single-wavelength light and a collimator 120 collimate the single- wavelength light generated by the light source 110. [31] Here, the light source 110 may be, preferably, a laser light source and other light source, such as a radiation beam source, which can generate a single- wavelength light. [32] The optical head 200 includes a spatial light modulator 210 disposed apart from by a distance and below the collimated light-supplying unit 100, a first microlens array 220 disposed over the spatial light modulator 210, and a second microlens array 230 disposed under the spatial light modulator 210. [33] The spatial light modulator 210 has a plurality of regions. A bundle of lights passing through the first microlens array 220 are respectively mapped one-to-one to a plurality of the regions. The spatial light modulator 210 also controls the respective regions to independently allow the lights to pass or cut off the lights. [34] The spatial light modulator 210 includes a liquid crystal part 240 divided into a plurality of regions, through which the lights passes, respective regions having a shutter function to selectively allow the lights to pass, and upper and lower glass substrates 250 and 260 disposed over and under the liquid crystal part 240 to protect the same.

[35] The first microlens array 220 is disposed over the upper glass substrate 250 to divide and refract the collimated light such that the divided lights are mapped one-to-one to the respective regions of the liquid crystal portion 240.

[36] The second microlens array 230 is disposed under the lower glass substrate 260 to condense the lights passing through the respective regions, so as to carry out a micro- patterning process. The second microlens array 230 can provide a beam spot of one micrometer or less in diameter, using aspheric microlenses with high numerical aperture.

[37] The substrate 310 may be a silicon wafer, a glass wafer or other substrates, on which photosensitive material, such as photoresist is applied.

[38] The substrate-driving unit 300 is a unit for moving the substrate along X, Y, and Z axes while supporting the same. It may be preferably a Plumbum Zirconate Titanate (PZT) actuator, which can precisely operate corresponding to an ultra-micro beam spot of one micrometer or less in diameter.

[39] A distance sensor 400 is disposed by the optical head 200. The distance sensor 400 measures a distance between the optical head 200 and the substrate 310 to be patterned so that the substrate 310 can be kept at a focal distance of the optical head 200. Since the distance sensor 400 enables the distance between the optical head 200 and the substrate 310 to be kept constant, a large-area patterning process can be performed effectively.

[40] Now, a description will be made of the operation of the optical lithography device according to the first embodiment of the invention.

[41] Light emitted from the light source 110 is transformed into collimated light while passing through the collimator 120. Then, the collimated light is divided into a plurality of beam fluxes and their optical paths are refracted while passing through the first microlens array 220. Then, the beam fluxes pass through the respective regions of the spatial light modulator 210. Here, the respective regions of the spatial light modulator 210 are individually controlled to selectively allow the lights to pass.

[42] The lights having passed through the respective regions of the spatial light modulator

200, are condensed through the second microlens array 230 to perform a micro- patterning process. The substrate 310 is then patterned by the lights condensed. A shape of the pattern is determined by operating the substrate-driving unit 300 to drive the substrate in the X-Y-Z directions.

[43] FIGS. 3 to 7 are process views illustrating manufacturing procedures of an optical head for the optical lithography device according to the first embodiment of the invention.

[44] First, as illustrated in FIG. 3, a first polymer 410 is applied onto the surface of the upper glass substrate 250 of the spatial light modulator 210. Here, the first polymer 410 may be photopolymer or thermosetting polymer. Next, a first mold member 420, having a lens pattern 430 thereon, is brought above the upper glass substrate 250.

[45] Here, the lens pattern 430 of the first mold member 420 has the same shape as that of the first microlens array to be formed.

[46] Next, as illustrated in FIG. 4, the first mold member 420 is moved down to press the first polymer against the upper glass substrate 250 of the spatial light modulator 210, so that the lens pattern 430 of the first mold member 420 is transferred onto the surface of the first polymer 410. Then, the first polymer is heated or is exposed to ultraviolet rays to cure, thereby preparing the first microlens array 220.

[47] The above manufacturing process of the first microlens array 220 may be carried out using an aligner. That is, the first mold member 420 is fixed at an upper position of the aligner where a mask is fixed, and the spatial light modulator 210 on which the first polymer 410 applied, is fixed at a lower position of the aligner where a substrate is fixed. Next, the first mold member 420 is aligned with the spatial light modulator 210 in conformity with an aligning mark formed on the upper glass substrate 250 of the spatial light modulator 210, and then is coupled with the spatial light modulator 210.

[48] Further, as illustrated in FIG. 5, the spatial light modulator 210 is turned upside down such that the lower glass substrate 260 faces upward, the second polymer 440 is applied onto the surface of the lower glass substrate 260, and finally a second mold member 450, having the lens pattern 460 thereon, is positioned above the lower glass substrate 260.

[49] Here, the first mold member 420 is kept coupled with the spatial light modulator 210.

This will play, in the following process, an important role in maintaining the shape of the first microlens array 220, which already has been cured, and the flatness relative to the lower glass substrate 260.

[50] Here, the lens pattern 460 of the second mold member 460 has the same shape as that of the second microlens array 230.

[51] Then, as illustrated in FIG. 6, when the second mold member 450 is coupled with the spatial light modulator 210, the lens pattern 460 of the second mold member 450 is transferred onto the surface of the second polymer 440. Next, the second polymer 440 is heated or is exposed to ultraviolet rays to cure, thereby preparing the second microlens array 230.

[52] Next, as illustrated in FIG. 7, after the first and second mold members 420 and 450 ar e separated from the spatial light modulator 210, the optical head 200 is finally manufactured.

[53] FIG. 8 is a view illustrating the construction of an optical lithography device according to a second embodiment of the present invention. [54] The optical lithography device includes a collimated light-supplying unit 100, an optical head 200 condensing the collimated light provided from the collimated light- supplying unit 100, and a substrate-driving unit 300 driving a substrate 310.

[55] The collimated light-supplying unit 100 and the substrate-driving unit 300 of the present embodiment have the same construction and operation as those of the first embodiment, so a detailed description thereof will be omitted.

[56] The optical head 200 of the present embodiment includes a spatial light modulator

210 disposed apart from by a distance and below the collimated light-supplying unit 100, a first microlens array 220 disposed over the spatial light modulator 210, and a second microlens array 230 disposed under the spatial light modulator 210. Further, an anti-reflection coating layer 510 and/or 520 is provided in at least one of positions between the spatial light modulator 210 and the first microlens array 220 and between the spatial light modulator 210 and the second microlens array 230.

[57] The spatial light modulator 210 and the first and second microlens arrays 220 and

230 of the present embodiment have the same constructions and operations as those of the first embodiment, so a detailed description thereof will be omitted.

[58] The anti-reflection coating layer 510 or 520 minimizes reflection of light, such that the majority of the light can pass through, thereby improving optical efficiency. The anti-reflection coating layer 510 or 520 has a thickness adequate to provide an optimum anti-reflection effect according to the wavelength of the light.

[59] FIG. 9 is a view illustrating the construction of an optical lithography device according to a third embodiment of the present invention.

[60] The optical lithography device of the present embodiment includes a collimated light-supplying unit 100 and a substrate-driving unit 300, which have the same construction as those of the first embodiment, and an optical head 600 having a structure different from that of the first embodiment.

[61] The optical head 600 includes a spatial light modulator 210 disposed apart from by a distance and below a collimated light- supplying unit 100, a first microlens array 610 disposed over an upper glass substrate 250 of the spatial light modulator 210 to divide collimated light such that divided lights are mapped one-to-one to respective regions of the spatial light modulator 210, a second microlens array 620 disposed under a lower glass substrate 260 of the spatial light modulator 210 to transform the lights passing through the spatial light modulator 210 into the collimated lights again, and a third microlens array 630 disposed apart from by a distance and below the second microlens array 620 to condense the collimated lights passing through the second microlens array 620, so as to perform a micro-patterning process. Here, the third microlens array 630 is convex downward because a focal distance thereof is generally short.

[62] The spatial light modulator 210 of this embodiment has the same construction and operation as those of the former embodiment, so a detailed description thereof will be omitted.

[63] In operation of the optical head of this embodiment, the collimated light, provided from the collimated light- supplying unit 100, is divided into the plurality of beam fluxes and their optical paths are refracted by the first microlens array 610, such that the beam fluxes pass through the respective regions of the liquid crystal part 240. The beam fluxes selectively pass through the plurality of regions, formed in the spatial light modulator 210. The beam fluxes, passing through the spatial light modulator 210, are transformed into the collimated lights again by the second microlens array 620, and the collimated lights are condensed by the third microlens array 630, and are irradiated toward the substrate.

[64] Consequently, the optical head of the third embodiment can improve its light- condensing capability by repeating the procedure of condensing lights toward plural regions.

[65] Although a preferred embodiment of the present invention has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

[1] An optical lithography device comprising: a collimated light- supplying unit, which provides collimated light; an optical head, which divides the collimated light toward a plurality of regions, selectively allows the divided lights to pass through the respective regions, and condenses the lights passing through the respective regions; and a substrate -driving unit, which drives a substrate to be patterned by the lights irradiated from the optical head.

[2] The optical lithography device according to claim 1 , wherein the collimated light-supplying unit includes a light source, which generates single- wavelength light, and a collimator, which collimates the single-wavelength light generated by the light source.

[3] The optical lithography device according to claim 1, wherein the optical head comprises: a spatial light modulator, which has a plurality of the regions, and controls the respective regions to selectively allow the lights to pass; a first microlens array, which is disposed over the spatial light modulator to divide and refract the collimated light such that the divided lights are mapped to the respective regions; and a second microlens array which is disposed under the spatial light modulator to condense the lights passing through the respective regions.

[4] The optical lithography device according to claim 3, wherein the optical head further comprises an anti-reflection coating layer, which is provided in at least one of positions between the spatial light modulator and the first microlens array and between the spatial light modulator and the second microlens array.

[5] The optical lithography device according to claim 1, wherein the optical head comprises: a spatial light modulator, which has a plurality of the regions, and controls the respective regions to selectively allow the lights to pass; a first microlens array, which is disposed over the spatial light modulator to divide and refract the collimated light such that the divided lights are mapped one-to-one to the respective regions; a second microlens array, which is disposed under the spatial light modulator to collimate the lights passing through the respective regions; and a third microlens array which is disposed under the second microlens array to condense the lights.

[6] The optical lithography device according to claim 1, wherein the optical head further comprises a distance sensor for measuring a distance between the optical head and the substrate to keep the distance constant.

[7] The optical lithography device according to claim 1, wherein the substrate- driving unit is a Plumbum Zirconate Titanate actuator. [8] A manufacturing method of an optical head for an optical lithography device, the method comprising: applying a first polymer onto a surface of an upper glass substrate of a spatial light modulator; forming a first microlens array by pressing a first mold member having a lens pattern thereon against the first polymer and curing the first polymer; applying a second polymer onto a surface of a lower glass substrate of the spatial light modulator; forming a second microlens array by pressing a second mold member having a lens pattern thereon against the second polymer and curing the second polymer; and separating the first and second mold members from the spatial light modulator. [9] The manufacturing method of an optical head according to claim 8, wherein each of the first and second polymers is a material having good light transmission, high hardness, and excellent heat resistance. [10] The manufacturing method of an optical head according to claim 8, wherein the first and second polymers are any one of photopolymer and thermosetting polymer.