KR20010088314A - Container for framed pellicle - Google Patents

Abstract

PURPOSE: To provide an improved pellicle container where the pellicle is hardly degraded in transmitivity of a exposure light beam, while pellicle is stored in the pellicle container. CONSTITUTION: Inorganic materials are used for at least the substance of the pellicle container or the substance of a layer 10 formed on the inner side surface of the pellicle container which houses the pellicle 6 and for the surfaces of the inner side and/or the outer side of the body 8 of the pellicle container made synthetic resin. It is preferable that the inorganic materials be of one or two kinds or more selected from among metals, glass, and ceramics.

Description

Frame Type Pellicle Container {CONTAINER FOR FRAMED PELLICLE}

The present invention relates to a frame type pellicle container, and more particularly, to a container for receiving a frame type pellicle used for dust protection of a photomask in a photolithographic patterning operation. In particular, an improvement of the present invention is the structure of a pellicle container containing a semiconductor device such as LSIs and VLSIs and a frame type pellicle used as a dustproof protective material of a photomask in the patterning operation of manufacturing fine and precise electronic devices including liquid crystal display panels. It is about.

Photolithographic patterning is a technique conventionally established in the manufacturing process of fine and precise electronic devices including liquid crystal display panels and semiconductor devices such as LSIs and VLSIs. In photolithographic patterning operations, the substrate surface of the device is patterned by exposure to actinic rays such as ultraviolet light through a pattern-bearing transparency called a photomask. Since the quality of patterning is greatly adversely affected by dust particles on the photomask surface due to absorption, dispersion and diffraction of the exposure light, it is very important that there be absolutely no dust particles deposited on the surface of the photomask. In this regard, photolithographic patterning operations are performed in clean room clean air, although it is impossible to completely remove dust particles even in the highest level clean room. Therefore, a conventional process is carried out by mounting a frame-type pellicle for dust protection on a photomask, and patterning light exposure is performed through the transparent pellicle membrane of the frame-type pellicle.

When patterning light exposure is carried out through a pellicle membrane of a frame type pellicle mounted on a photomask, the exposure light is focused on the photomask at least a few millimeters below the pellicle membrane, not on the dust particles. The deposited dust particles do not have a particularly adverse effect on the quality of the patterning.

Fig. 1 of the accompanying drawings shows a thin, very transparent, pellicle membrane of plastic resin applied to a rigid or rectangular frame 3 and a pellicle frame 3, referred to as a pellicle frame. A vertical cross-sectional view of a typical frame-type pellicle 6, which is basically an integrated device, which consists essentially of a film 1 referred to as, and is glued together in a form without looseness between the adhesive layers 2 between them. Indicates. The other end face of the pellicle frame 3 is usually coated with a pressure-sensitive adhesive forming the pressure-sensitive adhesive layer 4 in order to stably mount the frame-type pellicle 6 on the photomask. The surface of the pressure-sensitive adhesive layer 4 adheres to a detachable film or sheet 5 and is temporarily protected until use.

The plastic resin forming the pellicle membrane 1 has good mechanical strength and high transparency to exposure light even when forming a thin film, so that nitrocelluloses, cellulose acetates and fluorocarbon polymers ( fluorocarbon polymers). Glass plates are also proposed instead of the pellicle membrane 1 of plastic resin. The rigid material forming the pellicle frame 3 is usually selected from aluminum, stainless steel, polyethylene and the like. The pellicle membrane 1 is an acrylic resin-based adhesive or an epoxy resin-based adhesive according to US Patent No. 4,861,402, Japanese Patent Publication No. 58-219023, Japanese Patent Publication No. 7-168345, and the like. It is adhered to one end surface of the pellicle frame using an adhesive 2, which may be a resin-based adhesive, or a fluorocarbon resin-based adhesive. In another method, Japanese Patent Application Laid-Open No. 58-219023 applies an organic solvent having a good dissolving power to the plastic resin of the pellicle membrane 1 to the end face of the pellicle frame 3 and partially dryes it. A bonding method is proposed to bond 1) to the end face of the pellicle frame in a moderately wet state with a solvent.

The other end face of the pellicle frame 3, ie the end face opposite the pellicle membrane 1, is usually coated with a suitable pressure-sensitive adhesive of polybutene resin, polyvinyl acetate resin, acryl resin, or silicone resin. sensitive adhesive layer) 4 is provided. The surface of the pressure-sensitive adhesive layer 4 attaches a detachable sheet or separator 5, so that it is temporarily protected until the framed pellicle 6 is used, the detachable sheet or separator 5 being detachable sheet 5. Frameless pellicle 6 is removed by gently squeezing onto the photomask and peeling just before it is mounted on the photomask. The framed pellicle 6 with the separable sheet 5 described above is generally stored in a rigid container for the framed pellicle 6 made of plastic resin, in order to protect it until used against mechanical damage or contamination. Transported and stored.

For patterned exposed light through the pellicle membrane 1, in accordance with the demand for more precise resolution of photolithographic patterns in recent years, the exposed light gradually moves to shorter wavelengths in order to obtain a high pattern resolution. have. For example, the 436 nm and 365 nm wavelength g-ray and l-ray light, which were in the main stream of exposure light, were replaced by deep UV light of 248 nm wavelength with KrF excimer laser, followed by ArF excimer. The situation is being replaced by vacuum UV light of 193 nm wavelength of the laser. It is already predicted that shorter wavelengths of 158 nm, such as fluorine excimer laser beams, will be used for the exposure light of actual photolithographic patterning.

In order to perform patterned exposure in photolithography using the ultra-short light as the patterned exposure light, a very serious problem to be solved unexpectedly appears. That is, inevitably, the pellicle membrane 1 made of plastic resin absorbs the gaseous hydrocarbon compound and the moisture of the atmosphere somewhat, and this adsorbate has the effect of reducing the transmittance of the pellicle membrane 1 to the exposure light. In addition, this adsorbed gas is activated by a laser beam, which forms an initial position in the degradation reaction of the plastic resin of the pellicle membrane, resulting in a decrease in the durability of the frame-type pellicle 6.

Framed pellicles produced in the production line are each housed in plastic-made containers, which are typically stored for a considerable amount of time before the product is transported to the user for practical service, thus increasing the likelihood of contact with the contaminated gas described above. An opportunity is given during the storage of framed pellicles in the container. That is, the plastic resin constituting the container always contains various organic compounds such as unpolymerized monomer compounds and organic solvents as a polymerization medium, although in trace amounts, and these organic impurities are released from the container wall and accommodated in the container. It is absorbed by the pellicle membrane 1 of the mold pellicle 6 and acts in reverse as described above.

Accordingly, the object of the present invention is to solve the above problems, exhibiting the adverse effect of reducing the light transmittance and accelerating the deterioration of the pellicle membrane, the pellicle membrane of the frame type pellicle contained in the container for transportation and / or storage It is to provide a frame type pellicle container without the release of any organic matter that can be adsorbed.

1 is a schematic vertical cross-sectional view of a framed pellicle.

2 is a schematic vertical cross-sectional view of a container of the present invention, made entirely of inorganic material, containing a frame pellicle therein;

3 is a schematic vertical cross-sectional view of a container of the present invention in which both the inner and outer surface layers are made of inorganic material, containing a frame pellicle therein;

4 is a schematic vertical cross-sectional view of a container of the present invention wherein only the inner surface layer is made of an inorganic material, containing a frame pellicle therein;

* Description of the symbols for the main parts of the drawings *

1: pellicle membrane

2: membrane adhesive

3: pellicle frame

4: pressure-sensitive adhesive layer

5: detachable sheet or separator

6: frame type pellicle

7: pellicle container

7A: container base

7B: Covering

7C: Internal Space

8: pellicle container body

9: outer surface film

10: inner surface film

That is, the present invention provides an improvement of a frame-type pellicle container, which is an assembly of a covering that can be mounted on a container base that together with the container base forms an interior space for receiving the frame-type pellicle, the improvement being a metal, alloy. And an inorganic material selected from the group consisting of glass and ceramic materials, forming at least a container base facing the inner space and a surface layer of the covering.

While the minimum requirement of the present invention is to form the inner surface layer of the container with the inorganic material, the base body of the container and the entire body of the covering are both formed of the inorganic material, or both the inner and outer surface layers of the container are formed of the inorganic material. Is optional.

As shown in Fig. 2, the container 7 of the present invention is an assembly composed of a container base 7A and a covering 7B that can be mounted on the container base. When the covering 7B is mounted on the container base 7A, the inner space 7C is formed to receive the frame pellicle 6.

The most prominent feature of the present invention is that the frame pellicle container 7 has at least the surface layer of the container 7, that is, the surface layer of the container base 7A and the covering 7B facing the inner space 7C. Or inorganic material such as ceramic material. Examples of suitable metals and alloys for the purpose include aluminum, copper, iron and stainless steel. The surface of this metallic layer can be subjected to a variety of surface treatments to improve stability and corrosion resistance. For example, the surface of the aluminum layer may optionally be anodized to form an oxidized thin film thereon. Glass materials include fused silica glass and are not particularly limited. Silicon nitride, silicon carbide, zirconia, alumina and boron nitride are examples of ceramic materials used herein.

As shown in FIG. 2, instead of forming the entire body of the container 7 with the above-mentioned inorganic material, a vertical sectional view of receiving the frame-type pellicle 6 in the inner space, optionally as shown in FIG. 3. Have a composite layered structure composed of cores 8A or 8B made of this conventional plastic resin, and cladding layers 9,10 of inorganic material on the respective outer and inner surfaces of the cores 8A, 8B. can do. Of course, the cladding layer 9 of inorganic material on the container base and the outer surface of the covering is not essential, and the vertical cross section containing the frame pellicle 6 can also be omitted as shown in FIG. That is, the cladding layer 10 of the inorganic material is formed only on the surface of the container base 8A and the covering 8B of plastic resin facing the inner space 7C for accommodating the frame type pellicle 6. .

The cladding layer 10 of inorganic material on the inner surface of the cores 8A, 8B of the container should preferably have a thickness of at least 0.1 μm. If the thickness is too thin, the cladding layer of inorganic material is likely to form cracks or fissures in the end, so that the release of gas contaminated with organic matter from the cores 8A and 8B of the plastic resin can be completely blocked. none. The method of forming the cladding layer 10 of the inorganic material on the surfaces of the cores 8A and 8B is not particularly limited depending on the kind of the inorganic material and the predetermined thickness of the cladding layer 10. For example, the cladding layer 10 of inorganic material may be formed by a vacuum vapor deposition method or, optionally, by adhering a thin sheet of inorganic material using an adhesive.

The following is a description of the present invention, which will be described in more detail by Examples and Comparative Examples with reference to the accompanying drawings, the manufacturing process of the frame-type pellicle accommodated in the container.

As described above, one end surface of the pellicle frame is coated with a 0.5 mm thick silicone resin-based pressure-sensitive adhesive and the pressure-sensitive adhesive layer is protected by attaching a detachable film, while the frame-type pellicle 6A is made of silicone resin-based adhesive. It was made by adhering a 1 mm thick sheet of glass that served as a pellicle membrane on the other end face of the pellicle frame of coated aluminum.

The other framed pellicle 6B is almost the same, except that a 1 mm thick glass sheet is replaced with a 0.5 μm thick film of fluorocarbon resin that is spread and strongly bonded to the end face coated with the adhesive of the pellicle frame. Prepared by the method.

The pellicle membranes of the framed pellicles 6A, 6B have transmittances of 80% and 90%, respectively, for the fluorine excimer laser beam at a wavelength of 158 nm. In the examples and comparative examples below, these framed pellicles are held for a period of time in a variety of different pellicle containers, and measurements are made on the transmission of the pellicle membrane to the fluorine excimer laser beam after storage.

Example 1.

Framed pellicles 6A, 6B prepared as described above are stored in a pellicle container made entirely of aluminum for one month at room temperature, respectively. Frame-type pellicles (6A, 6B) removed from each pellicle container were 80% and 90%, respectively, without perturbation by the fluorine excimer laser beam.

Example 2.

The experimental procedure is practically the same as in Example 1, except that the pellicle container made of aluminum is replaced with a container made entirely of fused silica glass. After 1 month of storage therein, the permeation values of the pellicle membranes of the frame pellicles 6A, 6B show no decrease with the storage result, and are 80% and 90%, respectively, as measured by the fluoroine excimer laser beam.

Example 3.

The experimental procedure was carried out except that a pellicle container made of aluminum was replaced with a container made of a 0.1 μm thick aluminum cladding layer made of ABS resin and formed by vacuum vapor deposition on all surfaces of the container base and the covering. Is actually the same as After 1 month of storage therein, the permeation values of the pellicle membranes of the frame pellicles 6A, 6B show no decrease with the storage result, and are 80% and 90%, respectively, as measured by the fluoroine excimer laser beam.

Example 4.

The experimental procedure is practically the same as Example 3 except that a 0.1 μm thick aluminum cladding layer is formed only on the container base of ABS resin and the inner surface of the covering facing the inner space for accommodating the frame type pellicle. After 1 month of storage therein, the permeation values of the pellicle membranes of the frame pellicles 6A, 6B show no decrease with the storage result, and are 80% and 90%, respectively, as measured by the fluoroine excimer laser beam.

Example 5.

The experiment process consisted of a double layer structure in which the cladding layer on the surface of the container base and the covering was composed of a 0.5 μm thick aluminum bottom cladding layer and a 0.5 μm thick boron nitride top cladding layer, respectively, formed by vacuum vapor deposition. It is practically the same as Example 3 except having a. After 1 month of storage therein, the permeation values of the pellicle membranes of the frame type pellicles 6A and 6B showed no decrease according to the storage result, and 80% and 90% of the pellicle excimer laser beams were measured, respectively. to be.

Comparative example.

The experimental procedure was practically similar to that of Example 1 except that the pellicle container made of aluminum was replaced with a container made of polymethyl methacrylate resin having no inorganic cladding layer on the surface. same. After 1 month of storage, the pellicle membranes of the frame type pellicles (6A, 6B) were 47% and 50%, respectively, as measured by the fluorine excimer laser beam. .

As described above, the present invention provides a frame type pellicle container which does not emit any organic substance that can be absorbed by the frame type pellicle, and there is no decrease in transmittance even after long time storage of the pellicle in the pellicle container.

Claims (7)

In a frame type pellicle container, which is an assembly of a container base and a covering that can be mounted on the container base to form an interior space for receiving the frame type pellicle, A container, characterized in that for forming a cladding layer, an inorganic material selected from the group consisting of metals or alloys, glass materials and ceramic materials, forming at least the container base facing the inner space and the surface layer of the covering. The container as claimed in claim 1, wherein the container base and the covering of the container are entirely formed of an inorganic material. The container as claimed in claim 1, wherein the inorganic cladding layer is formed only on a surface of the container base made of plastic resin and the inner space of the covering. The container as claimed in claim 1, wherein the inorganic cladding layer is formed on both the container base made of plastic resin and the surface facing the inner space of the covering and the outer surface thereof. The container as claimed in claim 1, wherein the inorganic cladding layer has a thickness of 0.1 µm or more. A container according to claim 1, wherein the metal or alloy forming the cladding layer is selected from the group consisting of aluminum, copper, iron and stainless steel. A container according to claim 1, wherein the ceramic material forming the cladding layer is selected from the group consisting of silicon nitride, silicon carbide, zirconia, alumina and boron nitride.