KR20240061059A - Pellicle Frame with Filter and Method of Fabricating the Same - Google Patents

Abstract

The present invention relates to a pellicle frame and a method of manufacturing the same, and more specifically, to a pellicle frame equipped with a filter and a method of manufacturing the same. The present invention includes a hollow, cylindrical frame for supporting a pellicle membrane; It has a coupling part attached to at least one of the inner surface and the outer surface of the frame, and an extension part extending from the coupling part toward the photomask, and a plurality of pores through which gas can pass are formed in the extension part. The extension portion provides a pellicle frame equipped with a filter including a band-shaped film filter bent toward the frame. The pellicle frame according to the present invention has the advantage of being able to block foreign substances while ensuring breathability.

Description

Pellicle frame with filter and method of manufacturing the same {Pellicle Frame with Filter and Method of Fabricating the Same}

The present invention relates to a pellicle frame and a method of manufacturing the same, and more specifically, to a pellicle frame equipped with a filter and a method of manufacturing the same.

A method called photolithography is used to manufacture semiconductor devices or liquid crystal displays. In photolithography, a mask is used as a patterning plate, and the pattern on the mask is transferred to various layers formed on a wafer or liquid crystal substrate.

If dust adheres to the mask, light is absorbed or reflected due to the dust, which damages the transferred pattern, resulting in a decrease in performance or yield of semiconductor devices or liquid crystal displays.

Therefore, these works are usually performed in a clean room, but since dust exists even in this clean room, a method of attaching a pellicle is used to prevent dust from attaching to the mask surface.

In this case, the dust is not attached directly to the surface of the mask, but is attached to the pellicle film. During lithography, the focus is aligned with the pattern of the mask, so there is an advantage that the dust on the pellicle is not transferred to the pattern because it is out of focus.

The resolution required for exposure equipment for semiconductor manufacturing is gradually increasing, and in order to realize that resolution, the wavelength of the light source is becoming shorter and shorter. Specifically, the UV light source ranges from ultraviolet g-ray (436㎚), I-ray (365㎚), KrF excimer laser (248㎚), and ArF excimer laser (193㎚) to extreme ultraviolet (EUV, 13.5㎚). The wavelength is getting shorter.

In order to realize exposure technology using extreme ultraviolet rays, the development of new light sources, resists, masks, and pellicles is essential. That is, the conventional organic pellicle film has a problem in that it is difficult to use in a pellicle for extreme ultraviolet rays because its physical properties change due to exposure light sources with high energy and its lifespan is short. Various attempts are being made to solve these problems.

Additionally, conventionally, aluminum, stainless steel, polyethylene, etc. were used as a pellicle frame supporting the pellicle membrane, considering only rigidity and processability. However, during exposure using high-energy extreme ultraviolet rays, there is a problem that wrinkles or damage may occur in the pellicle film due to contraction and expansion of the pellicle frame due to a temperature increase due to light energy.

Therefore, methods of using materials with low thermal expansion coefficients such as Si, SiC, and SiN as materials for the pellicle frame are being studied. However, these materials had a problem in that it was difficult to fabricate ventilation holes to alleviate the pressure difference between the inside and outside of the pellicle. Typically, ventilation holes are formed on the side of the pellicle frame to prevent the pellicle membrane from being damaged by pressure differences when attaching or peeling the pellicle from the photomask.

Due to the difficulty in forming such ventilation holes and the deformation (PID, Pellicle-Induced Distortion) of the photomask due to attachment of the pellicle, a method of leaving a gap for ventilation between the pellicle and the photomask without forming a ventilation hole is also used. However, there is a problem that foreign substances may enter this gap and attach to the surface of the photomask.

Public Patent No. 2009-0088396 Public Patent No. 2009-0122114 Registered Patent No. 1552940 Registered Patent No. 1303795 Registered Patent No. 1940791 Public Patent No. 2016-0086024 Public Patent No. 2019-0005911 Public Patent No. 2019-0107603 Public Patent No. 2019-0040445 Public Patent No. 2008-0099920 Registered Patent No. 1866017

The present invention is intended to improve the above-mentioned problems and aims to provide a pellicle frame equipped with a filter for ventilation and a method of manufacturing the same.

In order to achieve the above-described object, the present invention includes a hollow cylindrical frame for supporting the pellicle membrane; It has a coupling part attached to at least one of the inner surface and the outer surface of the frame, and an extension part extending from the coupling part toward the photomask, and a plurality of pores through which gas can pass are formed in the extension part. The extension portion provides a pellicle frame equipped with a filter including a curved strip-shaped film filter.

Additionally, a concave adhesive receiving pattern is formed on the side of the frame, and the coupling portion provides a pellicle frame with a filter coupled to the side of the frame by an adhesive filled in the adhesive receiving pattern.

In addition, a pellicle frame is provided with a filter having irregularities formed inside the adhesive receiving pattern.

In addition, the ends of the uneven convex portions provide a pellicle frame with a filter located on the same plane as the side surface of the frame.

In addition, the present invention includes the steps of a) preparing a hollow, cylindrical frame to support the pellicle membrane, and b) providing a coupling portion and an extension portion extending from the coupling portion, the extension portion allowing gas to pass through. preparing a strip-shaped film filter with a plurality of pores, c) attaching the coupling portion to at least one of the inner and outer surfaces of the frame, and d) extending the extension portion so that it is bent. A method of manufacturing a pellicle frame including a filter including the step of processing the portion is provided.

In addition, step d) includes depositing a metal layer having higher thermal conductivity than the extension in a line shape on the surface of the extension along the longitudinal direction of the extension, and the metal deposited in a line shape through induction heating. A method of manufacturing a pellicle frame with a filter is provided, including heating the layer to shrink the extension portion on which the metal layer is formed.

In addition, in step d), the pellicle frame is coupled to the photomask, and when the extension part approaches the surface of the photomask, the extension part is charged to the same polarity as the surface of the photomask so that the extension part is bent. Provided is a method of manufacturing a pellicle frame with a filter including the step of:

In addition, a concave adhesive receiving pattern is formed on the side of the frame, and step c) includes filling the adhesive receiving pattern with adhesive, and using the adhesive filled in the adhesive receiving pattern to form the coupling portion on the frame. A method of manufacturing a pellicle frame with a filter including the step of coupling to the side is provided.

The pellicle frame according to the present invention has the advantage of being able to block foreign substances while ensuring breathability.

Figure 1 is a perspective view of a pellicle frame equipped with a filter according to an embodiment of the present invention.
Figure 2 is a cross-sectional view showing a portion of a pellicle frame equipped with a filter attached to a photomask.
Figure 3 is a flowchart of a method of manufacturing a pellicle frame equipped with a filter according to an embodiment of the present invention.
Figure 4 is a flowchart of a method of processing an extension through induction heating.
Figure 5 is a view showing an extension on which a metal layer is deposited.
Figure 6 is a diagram showing a state in which the extension part is bent due to repulsive force.
Figure 7 is a cross-sectional view showing a portion of a pellicle frame equipped with a filter according to another embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the attached drawings. The examples introduced below are provided as examples so that the idea of the present invention can be sufficiently conveyed to those skilled in the art. Accordingly, the present invention is not limited to the embodiments described below and may be embodied in other forms. And in the drawings, the width, length, thickness, etc. of components may be exaggerated for convenience. Like reference numerals refer to like elements throughout the specification.

Figure 1 is a perspective view of a pellicle frame equipped with a filter according to an embodiment of the present invention. Figure 2 is a cross-sectional view showing a portion of a pellicle frame equipped with a filter attached to a photomask.

As shown in Figures 1 and 2, the pellicle frame 100 equipped with a filter according to an embodiment of the present invention includes a frame 10 and a film filter 20 attached to the inner surface 14 of the frame 10. ) includes.

The frame 10 serves to support the pellicle membrane (not shown). The frame 10 has a hollow barrel shape. The frame 10 can be manufactured by wet etching or laser processing a silicon wafer or silicon bulk material.

The thickness of the frame 10 is 1.0 to 2.0 mm, the width is 4 to 6 mm, and in external dimensions, the length of the long side may be 130 to 170 mm and the length of the short side may be 100 to 140 mm.

As shown in Figures 1 and 2, the frame 10 has a first surface 11, which is the upper surface in the drawing, and a second surface 12, which is the lower surface in the drawing parallel to the first surface 11. Additionally, it has an outer surface 13 and an inner surface 14. A pellicle membrane (not shown) is coupled to the first surface 11 of the frame 10.

A pair of wings 16 may be coupled to the outer surface 13 of each long side of the frame 10. An engaging mechanism 30 configured to engage with the studs 3, which are protruding structures attached to the photomask 1, may be installed here. When the frame 10 is coupled to the photomask 1, the second side 12 of the frame 10 faces the surface to which the studs 3 of the photomask 1 are attached and the gap is between them.

The pellicle attachment device for attaching the pellicle to the photomask 1 can couple the stud 3 and the engagement mechanism 30 by manipulating the engagement mechanism 30 using a plurality of hook-shaped members and manipulator pins.

The engaging mechanism 30 and studs 3 of FIGS. 1 and 2 are just one example structure for coupling the frame 10 to the photomask 1, and various coupling structures can be used to connect the frame 10 to the photomask 1. The frame 10 can be attached to the photomask 1 while maintaining a gap between the second surface 12 and the surface of the photomask 1.

An adhesive receiving pattern 18 may be formed on the inner surface 14 of the frame 10. The adhesive receiving pattern 18 is concavely formed on the inner surface 14 of the frame 10. The adhesive receiving pattern 18 can be formed through wet etching, dry etching, or laser processing. The adhesive receiving pattern 18 can be formed in a square or circular shape. The adhesive receiving pattern 18 may be formed over the entire inner surface 14, but may also be formed intermittently, as shown in FIGS. 1 and 2. Irregularities 19 are formed inside the adhesive receiving pattern 18. The unevenness 19 may be formed long along the length or width direction of the adhesive receiving pattern 18. The end of the convex portion of the unevenness 19 may be located on the same plane as the inner surface 14. The adhesive receiving pattern 18 can be formed to a depth of about 0.05 μm to 100 μm.

An adhesive (not shown) is applied to the adhesive receiving pattern 18. There is no particular limitation on the adhesive material, and known materials can be used. For example, an adhesive whose main materials are acrylic resin, silicone resin, epoxy resin, etc. can be used. Adhesives can be applied using a dispenser, spray, or brush. If the adhesive is exposed to the outside, it may be decomposed by an exposure light source such as EUV and may contaminate the surface of the pellicle film and the photomask 1, so it is advantageous to apply it within the adhesive receiving pattern 18.

A silicon nitride or silicon oxide protective layer may be formed on the surface of the frame 10. The protective layer can be formed by deposition through a CVD or PVD process, for example, a low pressure chemical vapor deposition (LPCVD) process or an atomic layer deposition (ALD) process.

As shown in Figures 1 and 2, the film filter 20 has a long strip shape. The film filter 20 is attached along the entire inner surface 14 of the frame 10. The film filter 20 is a porous film. Activated carbon, metal, polypropylene, poly-sulfone, polytetrafluoroethylene, etc. may be used as materials for the film filter 20. A plurality of pores are formed in the film filter 20 to allow ventilation but block the inflow of foreign substances.

The film filter 20 includes a long strip-shaped coupling portion 21 and an extension portion 22 extending from the coupling portion 21 in the width direction of the coupling portion 21. A number of pores are formed in the extension portion 22. There is no need for pores to be formed in the coupling portion 21, but for convenience, the coupling portion 21 may be made of the same porous film as the extension portion 22.

As shown in FIG. 2, after the frame 10 is coupled to the photomask 1, the gap between the photomask 1 and the frame 10 is blocked by the outwardly curved extension portion 22. . Therefore, external foreign substances do not flow into the internal space surrounded by the photomask 1 and the pellicle. The extension portion 22 may be bent inward.

Figure 3 is a flowchart of a method of manufacturing a pellicle frame equipped with a filter according to an embodiment of the present invention.

As shown in Figure 3, the method of manufacturing a pellicle frame with a filter according to an embodiment of the present invention includes a) a step of preparing the frame (S1), and b) a strip shape having a coupling portion and an extension portion. It includes the steps of preparing a film filter (S2), c) attaching the coupling portion to the inner surface of the frame (S3), and d) processing the extension portion so that the extension portion is bent (S4).

First, the step S1 of preparing the frame 10 will be described.

As described above, the frame 10 has a hollow cylindrical shape. The frame 10 can be manufactured by wet etching or laser processing a silicon wafer or silicon bulk material.

Next, the step (S2) of preparing the film filter 20 will be described.

As described above, the film filter 20 has a long strip shape. The film filter 20 is a porous film.

Next, the step (S3) of attaching the coupling portion 21 to the inner surface 14 of the frame 10 will be described.

In this step, the coupling portion 21 is attached to the inner surface 14 of the frame 10 using, for example, an adhesive. The adhesive may be applied to the adhesive receiving pattern 18 formed on the inner surface 14 of the frame 10.

When the coupling portion 22 is attached to the inner surface 14 of the frame 10, the extension portion 22 of the film filter 20 protrudes below the second surface 12 of the frame 10.

Next, a step (S4) of processing the extension portion 22 so that the extension portion 22 is bent will be described.

This step can be carried out in various ways. For example, the extension portion 22 may be bent by locally heating and shrinking the outer or inner surface of the extension portion 22 using heat or an electron beam. More specifically, extension 22 can be locally heated by applying a heated thin tip to the outer or inner surface of extension 22.

Another method is a treatment method using induction heating.

Figure 4 is a flowchart of a method of processing an extension through induction heating, and Figure 5 is a diagram showing an extension on which a metal layer is deposited.

As shown in FIG. 4, the present method forms a metal layer 125 with higher thermal conductivity than the extension 122 on the outer or inner surface of the extension 122 along the longitudinal direction of the extension 122 in a line shape. It includes a step of depositing (S41) and a step of heating the metal layer 125 deposited in a line shape through induction heating to shrink the extension portion 122 on which the metal layer 125 is formed (S42).

As the metal layer 125, various metals capable of induction heating may be used. For example, iron, nickel, nichrome, etc. may be used. During induction heating, the outer or inner extension portion 122 on which the metal layer 125 is deposited is locally contracted due to heating of the metal layer 125, so the extension portion 122 may be bent. The metal layer 125 may be formed in the extension portion 122 close to the coupling portion 121.

Another method is to charge the extension portion 222 to the same polarity as the surface of the photomask 1. Typically, the photomask 1 is charged to - polarity within the exposure equipment.

Therefore, as shown in FIG. 6, when the pellicle frame 100 is coupled to the photomask 1 in a state in which the extension portion 222 is charged with the same polarity - polarity, the extension portion 222 is connected to the photomask 1. ), the extension portion 222 is bent toward the outside or inside of the frame 10 due to the repulsive force.

Figure 7 is a cross-sectional view showing a portion of a pellicle frame equipped with a filter according to another embodiment of the present invention. This embodiment differs from the embodiment shown in FIG. 6 in that the film filter 50 is attached not only to the inner surface 44 but also to the outer surface 43 of the frame 40. The film filters 50 are bent toward the frame 40.

In the above, preferred embodiments of the present invention have been shown and described, but the present invention is not limited to the specific embodiments described above, and may be commonly used in the technical field to which the invention pertains without departing from the gist of the present invention as claimed in the claims. Of course, various modifications can be made by those skilled in the art, and these modifications should not be understood individually from the technical idea or perspective of the present invention.

1: Photomask
3: stud
100: Pellicle frame
10, 40: frame
11: side 1
12: Side 2
13, 43: outer surface
14, 44: inner surface
16: wings
18, 48: Adhesive receiving pattern
19: irregularities
20, 50, 120, 220: Film filter
21, 121, 221: joint
22, 122, 222: extension
125: metal layer
30: Engagement mechanism

Claims (8)

A hollow barrel-shaped frame for supporting the pellicle membrane,
It has a coupling part attached to at least one of the inner surface and the outer surface of the frame, and an extension part extending from the coupling part toward the photomask, and a plurality of pores through which gas can pass are formed in the extension part. The extension portion is a pellicle frame equipped with a filter including a curved strip-shaped film filter. According to paragraph 1,
A concave adhesive receiving pattern is formed on the side of the frame,
The coupling portion is a pellicle frame having a filter coupled to the side of the frame by an adhesive filled in the adhesive receiving pattern. According to paragraph 2,
A pellicle frame provided with a filter having irregularities formed inside the adhesive receiving pattern. According to paragraph 3,
A pellicle frame with a filter in which the end of the uneven convex portion is located on the same plane as the side of the frame. a) preparing a hollow, barrel-shaped frame to support the pellicle membrane,
b) preparing a strip-shaped film filter having a coupling portion and an extension portion extending from the coupling portion, the extension portion having a plurality of pores through which gas can pass;
c) attaching the coupling portion to at least one of the inner and outer surfaces of the frame;
d) A method of manufacturing a pellicle frame including a filter including the step of processing the extension portion to bend the extension portion. According to clause 5,
In step d),
depositing a metal layer having higher thermal conductivity than the extension portion in a line shape on the surface of the extension portion along the longitudinal direction of the extension portion;
A method of manufacturing a pellicle frame with a filter, comprising the step of heating the metal layer deposited in a line shape through induction heating and shrinking the extension portion on which the metal layer is formed. According to clause 5,
In step d),
A filter comprising the step of coupling the pellicle frame to a photomask and charging the extension to the same polarity as the surface of the photomask so that the extension is bent when the extension approaches the surface of the photomask. Manufacturing method of one pellicle frame. According to clause 5,
A concave adhesive receiving pattern is formed on the side of the frame,
In step c),
filling the adhesive receiving pattern with adhesive;
A method of manufacturing a pellicle frame with a filter, comprising the step of coupling the coupling portion to the side of the frame using an adhesive filled in the adhesive receiving pattern.

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