JP2001005169A - Pellicle and pellicle manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a pellicle which obviates the occurrence of damage, wear, etc., of a filter by contact of a jig for sticking the pellicle with the filter even if the pellicle is provided with the filter and does not generate foreign matter due to the damage or wear of the filter by arranging the filter in a cut part disposed at a pellicle frame. SOLUTION: This pellicle includes the cut part 2 at least at one point and the filter 3 arranged in the cut part 2. The cut part 2 is formed into a shape in which a part of one side of the pellicle frame 1 is cut off at a prescribed width from its top end face to its bottom end face. The pellicle is formed by spreading a pellicle film to the top end face of the pellicle frame 1 arranged with the filter within the cut part 2. The top end face of the pellicle frame 1 is usually provided with an adhesive layer 5 in order to adhere the pellicle film to the pellicle frame 1. In such a case, since the top end face of the filter 3 and the top end face of the pellicle frame 1 may be formed at the same plane, the adhesive layer 5 can be flattened even in the filter 3 part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pellicle provided with a vent hole having a filter in a pellicle frame so as not to cause swelling or dent in a pellicle film due to an external pressure change, and a method for manufacturing the pellicle. is there.

[0002]

2. Description of the Related Art In the manufacture of semiconductor devices such as LSIs and super LSIs or liquid crystal display devices, an exposure original (a photomask, a reticle and the like in this specification) is placed on a semiconductor wafer such as a silicon wafer or a liquid crystal original. Lithography is performed by irradiating the exposed original plate with light and transferring a pattern by light transmitted through the exposed original plate.

However, if foreign matter (dust) adheres to the exposure original in such a process, the foreign matter absorbs or bends the light, and is transferred onto a semiconductor wafer or a liquid crystal original. In addition to the deformation of the pattern and the rough edges, the white background becomes dirty with black, and the dimensions, quality, appearance, etc. are impaired.As a result, the performance and manufacturing yield of semiconductor devices and liquid crystal display devices are reduced. The problem of lowering occurs.

[0004] To avoid such a problem, lithography is usually performed in a clean room. However, it is difficult to keep the exposure original plate completely clean even in a clean room. Therefore, a method has been adopted in which a pellicle that transmits light for exposure well is attached so that foreign matter and the like do not adhere to the surface of the exposure original plate. When the pellicle is mounted in this manner, foreign matter (dust) does not directly adhere to the surface of the exposure original plate, but adheres to the pellicle film. Therefore, if the focus is set on the pattern of the exposure original during lithography, the presence of such foreign matter (dust) is not related to the transfer, and the above-described problem does not occur.

When the pellicle is mounted on the exposure master, the pellicle is usually brought into close contact with the exposure master to prevent dust from entering between the pellicle and the exposure master, and as a result, a space formed by the exposure master and the pellicle. Is an airtight space. On the other hand, the pellicle is normally used under the atmospheric pressure, but the pellicle may undergo a slight change in the atmospheric pressure depending on conditions such as transportation and a place of use. For example, during air transportation or when the place of use is at a high altitude, the air pressure becomes low. When the pellicle is air-tightly attached to the exposure original plate and receives a change in air pressure, the pellicle film swells or dents, causing a change in the height of the pellicle film.
As a result, there have been serious problems in use such as, for example, the case of the photomask and the pellicle film being in contact with each other, or foreign matter (dust) on the pellicle film cannot be detected.

In order to solve such a problem, for example, a pellicle as shown in FIGS. 4 and 5 is used (JP-A-9-68792). This pellicle 21
Is composed of a pellicle frame 24 which is in close contact with the exposure original plate 22 via an adhesive layer 23, and a pellicle film 25 adhered to the upper surface of the pellicle frame. The pellicle frame 24 has small holes 26 for ventilation. Are formed, and the small holes 26 are formed.
A filter 27 is attached to the outside of the pellicle frame 24 so as to cover the small holes 26 by, for example, a double-sided tape or the like in order to prevent entry of foreign matter from air moving through the filter.

[0007]

However, the filter 27 is thus mounted outside the pellicle frame 24. Therefore, the filter 27 is attached so as to protrude from the outer peripheral surface of the pellicle frame 24. The pellicle 21 with the filter 27 protruding and attached thereto is attached to the original exposure plate 22 by using a pellicle jig to which a normal filter is not attached (hereinafter, sometimes referred to as a pellicle sticking jig). When the pellicle bonding jig comes into contact with the filter 27, the filter 27 is damaged or rubbed. When the filter is damaged or worn in this way, there is a problem that foreign matter is generated. The present invention has been made in view of the above problems, and even in the case where a filter is provided, a pellicle which does not cause damage to or abrasion of the filter due to the contact of the pellicle attaching jig with the filter and thereby does not generate foreign matter. Another object of the present invention is to provide a method for manufacturing such a pellicle.

[0008]

In order to achieve the above object, according to the present invention, at least one cut portion is provided in a pellicle frame, and a filter is disposed in the cut portion. By arranging the filter in the cut portion provided on the pellicle frame in this way, the filter is not arranged to protrude outside the pellicle frame. Therefore, even when the pellicle is stuck to the exposure original using a pellicle sticking jig or the like, the filter is not damaged or worn, and does not cause foreign matter.

In this case, the height of the cut portion and the length of the filter in the height direction of the cut portion are preferably equal to each other. Cutting section height,
That is, by setting the length of the pellicle frame from the exposure original side to the pellicle film side and the length of the filter in the height direction to be the same length, the upper end surface of the filter arranged in the cutting portion and the pellicle frame upper end surface, The lower end surface of the filter can be flush with the lower end surface of the pellicle frame.

Accordingly, when the adhesive layer for bonding the pellicle film to the pellicle frame is applied to and formed on the upper end surface of the pellicle frame, it can be easily formed on a flat surface in the filter portion. No unnecessary distortion or the like is caused. Also, when an adhesive layer for bonding to the exposure master is formed on the lower surface of the pellicle frame, a flat surface can be easily formed in the filter portion, and no unnecessary gap is generated between the pellicle and the exposure master, and foreign matter is not generated. Can be prevented.

Further, as described in claim 3, it is preferable that the length of the filter in the width direction of the cut portion is equal to or shorter than the width of the cut portion. This is because the width of the cut part, that is, the distance between the outer peripheral surface and the inner peripheral surface of the pellicle frame, and the length of the filter in the width direction are the same or the filter is shorter, so that the filter becomes This is because the filter does not protrude outward from the outer peripheral surface of the frame, and therefore, there is no generation of foreign matter due to damage or abrasion of the filter caused when the filter protrudes from the outside of the pellicle frame. Similarly, since the filter does not protrude inward, there is a problem that occurs when the filter protrudes to the inner surface side.For example, in the case of a foreign substance inspection, a protruding portion causes stray light and makes it difficult to perform a foreign substance inspection. Does not occur.

Further, as described in claim 4, it is preferable that the filter is impregnated with an adhesive. As described above, since the filter is impregnated with the adhesive, the filter does not generate any foreign matter due to damage or abrasion. In addition, foreign matter passing through the filter can be efficiently captured, and the inside of the filter can be efficiently captured. Foreign matter generated in the pellicle can be prevented from entering the inside of the pellicle. Thereby, the effect of preventing foreign matter from entering the inside of the pellicle can be improved.

Furthermore, as described in claim 5, the visible light reflectance of the filter is preferably 50% or less. Thus, the visible light reflectance of the filter is 50
%, The color of the filter becomes slightly black and no longer glows, so that the foreign matter inspection sensitivity can be increased when inspecting foreign matter on the inner wall of the frame with the condenser lamp.

According to a sixth aspect of the present invention, there is provided a pellicle frame including a step of forming a pellicle frame having a cut portion, a step of arranging a filter in the cut portion, and a pellicle having a cut portion in which the filter is arranged. Forming a pellicle film on a frame. As described above, by using the pellicle frame provided with the cut portion and manufacturing the pellicle such that the filter is arranged in the cut portion, the obtained pellicle does not protrude on the outer peripheral surface thereof. Therefore, when the pellicle is stuck to the exposure original using a pellicle sticking jig or the like, the filter is not damaged or worn, and no foreign matter is generated.

At this time, as described in claim 7, it is preferable that the thickness of the filter before being arranged in the cut portion is equal to or greater than the thickness of the cut portion before the filter is arranged. By using a filter having a thickness equal to or greater than the thickness of the cut portion, an unnecessary transparent space is not formed between the cut portion and the filter, which can prevent foreign substances from entering the inside of the pellicle. is there. Also, if the thickness of the filter is greater than the thickness of the cut,
The filter can be sandwiched between the cut portions by using the bending of the pellicle frame. Therefore, the filter can be fixed to the cut portion without using an adhesive.

[0016]

Next, embodiments of the present invention will be described, but the present invention is not limited to these embodiments. The pellicle of the present invention is characterized by including a pellicle frame having at least one cut portion and a filter disposed at the cut portion. Here, the cut portion has a shape in which a part of one side of the pellicle frame 1 is cut from the upper end surface to the lower end surface with a predetermined width, as shown in FIG. 1, for example. Here, the upper end surface of the pellicle frame 1 is an end surface to which a pellicle film is adhered, and the lower end surface is an end surface that is in close contact with the original exposure plate.

The shape of the cut portion 2 may be formed perpendicular to the upper end surface and the lower end surface of the pellicle frame 1, or may be formed obliquely at a predetermined angle. There may be. In addition, the cutting section 2 corresponds to FIGS.
However, the present invention is not limited to this, and two or more places may be provided as necessary.

In the present invention, as shown in FIG. 2, a filter 3 is arranged in the cutting section 2. Examples of the material of the filter 3 used here include a resin represented by polyethylene, ceramics such as alumina, and the like, and in any case, the material is particularly limited as long as it is porous and has air permeability. Not something.

The filter 3 may be impregnated with an adhesive. By being impregnated with the adhesive, in addition to the effect that the filter itself does not generate foreign matter due to damage and abrasion, foreign matter passing through the filter can be captured, and foreign matter generated inside the filter inside the pellicle. The effect that the approach to can be prevented can be obtained. Thereby, foreign substances inside the pellicle can be significantly reduced. The impregnation amount of the pressure-sensitive adhesive is not particularly limited as long as the air permeability is maintained. The type of the pressure-sensitive adhesive to be impregnated is not particularly limited, and examples thereof include a silicone-based pressure-sensitive adhesive.

The filter 3 preferably has a visible light reflectance of 50% or less. This is because it is preferable that the color of the filter is black when it is inspected for foreign matter on the inner wall of the frame by a condensing lamp because it does not shine, and the white filter that is normally used shines on the inner wall of the frame. Is unnecessarily reduced.

Next, the shape of the filter 3 will be described. The filter 3 used in the present invention is disposed in the cutting section 2 as shown in FIG. In the present invention, it is preferable that the thickness of the filter 3 after being arranged in the cut portion 2 is the same as the thickness of the cut portion 2. If the thickness is not the same, a gap is generated between the filter 3 and the cut end face 4, and there is a possibility that foreign matter enters from the gap. This cutting part 2
Specifically, the thickness of the filter 3 after being placed in the pellicle is 0.5 mm, depending on the size and shape of the pellicle.
It is preferably within a range of 2 mm. The filter 3 may be provided with an adhesive layer for bonding the filter 3 and the cut end face 4 of the cut section 2.

The height of the filter 3, that is, the length of the portion corresponding to the height direction of the cut portion 2 is preferably the same as the height of the cut portion 2. Here, the height of the cut portion 2 indicates a distance between the upper end surface and the lower end surface of the pellicle frame 1. As described above, by setting the length to be the same as the height of the cut portion 2, the upper end of the filter 3 can be made the same plane as the upper end surface of the pellicle frame 1 as shown in FIG. Therefore, to adhere the pellicle film to the pellicle frame,
When the adhesive layer 5 is formed on the upper surface of the pellicle frame, a flat surface can be easily formed even in the portion of the filter 3 (cut portion 2), and unnecessary distortion is given to the pellicle film after bonding the pellicle film. There is no.

Similarly, the lower end of the filter 3 can be flush with the lower end surface of the pellicle frame 1. Therefore, when the adhesive layer 6 is formed on the lower end surface of the pellicle frame 1 in order to adhere the pellicle frame 1 to the exposure original, a flat surface can be easily formed in the portion of the filter 3 (cut section 2), and When bonded, there is no gap or the like, and the invasion of foreign matter can be prevented. Note that the height of the cut portion 2 when the cut portion 2 is not perpendicular to the upper end surface and the lower end surface of the pellicle frame 1 indicates the length from the upper end surface to the lower end surface of the cut end surface 4.

The length of the filter 3 corresponding to the width direction of the cut portion 2 is preferably equal to or shorter than the width of the cut portion 2. Here, the width of the cut portion 2 refers to the distance from the inner peripheral surface to the outer peripheral surface of the pellicle frame 1. This is because, by making the length of the filter 3 in the width direction of the cut portion 2 equal to or shorter than the width of the cut portion 2, for example, as shown in FIG. It does not protrude outside. Therefore, the pellicle frame 1
This is because there is no generation of foreign matter due to damage or wear of the filter 3 that occurs when the filter 3 protrudes from the outside. Similarly, since the filter 3 does not protrude to the inner peripheral side, a problem that occurs when the filter 3 protrudes to the inner surface side, such as a problem that a protruding portion causes stray light and makes it difficult to perform a foreign substance inspection in a foreign substance inspection. Does not occur.

The pellicle of the present invention has
A pellicle film is stretched on an upper end surface of a pellicle frame 1 in which a filter 3 is disposed. The material for forming the pellicle film used in the present invention is not particularly limited as long as it is a material that allows light to pass well.For example, nitrocellulose, cellulose acetate, modified polyvinyl alcohol, and a fluorine-based polymer are preferable. Particularly preferred is a fluorine-based polymer, among which a copolymer of tetrafluoroethylene and vinylidene fluoride, a terpolymer of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride, and a tetrafluoroethylene and cyclic perfluoroether group An amorphous fluorine-based polymer such as a copolymer with a fluorine-containing monomer is preferred. This is because such an amorphous fluorine-based polymer has a high light transmittance, can be widely used from a short wavelength to a long wavelength region, and has excellent light resistance.

In the present invention, an adhesive layer 5 is usually provided on the upper end surface of the pellicle frame 1 in order to adhere the pellicle film to the pellicle frame 1. In this case, since the upper end surface of the filter 3 and the upper end surface of the pellicle frame 1 can be flush with each other as described above, the adhesive layer 5 is flattened even in the filter 3 portion. be able to. Therefore, even when the pellicle film is stretched on the adhesive layer 5, the pellicle film is not adversely affected by unnecessary distortion or bending. The type of adhesive used for the adhesive layer 5 is not particularly limited, and when bonding is performed by heating, a thermoplastic resin or a thermosetting resin is used as the adhesive, and light curing is used. In the case of performing the bonding by using, a photocurable resin is used as an adhesive.

Further, in the present invention, an adhesive layer 6 for mounting on the exposure master is provided on the lower end side of the pellicle frame 1.
And a release layer for protecting this. Also in this case, since the lower end surface of the filter 3 arranged in the cutting section 2 and the lower end surface of the pellicle frame 1 can be flush with each other, the adhesive layer 6 having no unevenness even in the filter 3 portion is formed. Thus, an unnecessary gap is not formed between the exposed original and the exposure master, and the invasion of foreign matter can be prevented.

Next, a method for manufacturing such a pellicle will be described. First, a pellicle frame having at least one cut portion is prepared. The pellicle frame may be formed in a shape having a cut portion in advance, or a cut portion may be formed by cutting the pellicle frame after molding. The pellicle frame used here may be circular or rectangular, and its material is not particularly limited. For example, aluminum alloy, metal such as stainless steel, plastic such as polyethylene, or silicon carbide, Materials such as ceramics such as alumina can be used.

Next, a filter is attached to such a pellicle frame. It is preferable that the thickness of the filter before being attached to the cut portion is equal to or slightly larger than the thickness of the cut portion before the filter is attached. Specifically, the thickness of the filter before mounting is 0.5 mm to
It is preferable that the distance is in the range of 2 mm.
It is preferably within the range of 3 mm. The thickness of the cut portion before the filter is attached is preferably in the range of 0 to 2 mm because it is preferably equal to or slightly smaller than the thickness of the filter before the attachment.

The filter may be attached to the cut portion by applying an adhesive or a pressure-sensitive adhesive to the filter and providing an adhesive layer to fix the filter to the cut portion, or a filter which is slightly thicker than the cut portion. May be inserted into the cutting portion and fixed using the force of sandwiching due to the bending of the filter. The adhesive or pressure-sensitive adhesive is not particularly limited, and a commonly used instant adhesive or the like can be used. When the filter is impregnated with an adhesive, the same material as the adhesive may be used.

The pellicle of the present invention is manufactured by stretching the pellicle film on the pellicle frame on which the filter is mounted as described above. The adhesion of the pellicle film to the pellicle frame can be performed by a conventionally performed method,
For example, a heat fusion method is used.

[0032]

The present invention will be described below with reference to examples and comparative examples. (Example) Height is 6.3 mm, outer circumference is 120 mm square, inner circumference is 116 mm square, width is 2 mm, and thickness is 1 at the center of one side.
A pellicle frame made of aluminum having one cut section of mm and having an anodized aluminum surface was prepared. A porous polyethylene sheet (height × width × thickness = 6.3 mm × 2 mm × 1 mm) was sandwiched between the cut portions, and was adhered and fixed to the cut portion of the pellicle frame with an instant adhesive.

Next, a silicone adhesive KR-120 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) is applied to the lower end surface of the pellicle frame.
At a temperature of 120 ° C. and a thickness of 0.6 mm.
The mixture was cured for 0 minutes to form an adhesive layer. Furthermore, on the top surface of the pellicle frame, Cytop CTX, which is a fluororesin,
-A type (made by Asahi Glass Co., Ltd., trade name) with a thickness of 0.1 mm
To form an adhesive layer. On the other hand, a pellicle film as a 1.62 μm thin film was formed using a Cytop CTX-S type (a product of Asahi Glass Co., Ltd., a fluororesin). The pellicle film was heat-fused and adhered at a temperature of 108 ° C. on the adhesive layer of the pellicle frame to be stretched.

The pellicle thus manufactured was placed on a glass substrate and attached to the upper end surface of the pellicle frame with a load of 30 kg. At this time, the attachment was performed using a pellicle jig without a filter (pellicle attachment jig).
There was no damage or abrasion of the filter upon application, and no generation of foreign matter due to this was observed. After placing the pellicle attached to this glass substrate in a vacuum container,
The pressure was reduced to 2/3 atm for 30 seconds, and then the state of swelling of the pellicle film was observed while maintaining the pressure. As a result, immediately after the completion of the pressure reduction, the swelling of the pellicle film was reduced by 6 mm compared to the normal state, but after 40 minutes.

(Comparative Example) The same pellicle frame as in the example was used except that a small hole of 0.5 mmφ was provided from the outer surface to the inner surface of the pellicle frame instead of the cut portion. A filter diameter of 3 μm and a size of 10 mm × 2 mm outside the small hole
Was attached to the glass substrate with the same load as the pellicle attaching jig similar to the example. At the time of sticking, the jig for sticking the pellicle was in contact with the filter, and the filter was damaged, and foreign matter generated was recognized. The pellicle attached to this glass substrate was subjected to the same pressure change as in the example, and the change in film height was measured. Immediately after the completion of the depressurization, the swelling of the pellicle film was reduced by 6 mm compared to the normal state, but after 40 minutes, the swelling of the pellicle film had been eliminated.

The present invention is not limited to the above embodiment. The above embodiment is an exemplification, and has substantially the same configuration as the technical idea described in the scope of the claims of the present invention. It is included in the technical scope of the invention.

[0037]

The present invention is directed to a pellicle having a pellicle frame having at least one cut portion and a filter disposed at the cut portion. Even when affixed to an exposure original plate, the filter is not damaged or worn, and has the effect of not causing the generation of foreign matter.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of a pellicle frame used in the present invention.

FIG. 2 is an enlarged side view showing a state where a filter is attached to a cut portion of the pellicle frame shown in FIG.

FIG. 3 is a side view showing a part of an example of the pellicle of the present invention.

FIG. 4 is a perspective view showing a conventional pellicle mounted on an exposure master.

5 is a longitudinal sectional view of the conventional pellicle shown in FIG. 4 taken along line AA ′.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Pellicle frame, 2 ... Cut part, 3 ... Filter, 4 ... Cut end face, 5 ... Adhesive layer,
6 ... adhesive layer, 21 ... pellicle, 22 ... exposure master, 23 ... adhesive layer, 24 ... pellicle frame,
25 ... pellicle membrane, 26 ... small holes, 27 ...
filter.

Claims (7)

[Claims] 1. A pellicle comprising a pellicle frame having at least one cut portion and a filter disposed at the cut portion. 2. The pellicle according to claim 1, wherein the height of the cut portion is equal to the length of the filter in the height direction of the cut portion. 3. The pellicle according to claim 1, wherein a length of the filter in a width direction of the cut portion is equal to or shorter than a width of the cut portion. 4. The pellicle according to claim 1, wherein the filter is impregnated with an adhesive. 5. The visible light reflectance of the filter is 50%.
The pellicle according to any one of claims 1 to 4, wherein: 6. A step of forming a pellicle frame having a cut portion, a step of disposing a filter in the cut portion, and a step of stretching a pellicle film on the pellicle frame having a cut portion in which the filter is disposed. A method for producing a pellicle, comprising: 7. The method for manufacturing a pellicle according to claim 6, wherein the thickness of the filter before being disposed in the cut portion is equal to or greater than the thickness of the cut portion before the filter is disposed. .