JPH1062966A - Pellicle for lithography - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent production of dust and to avoid such problems that a pellicle film expands and break even when environmental conditions such as external air or temp. change by providing an adhesive layer with an aeration filter to adhere and fix a pellicle to an exposure master plate. SOLUTION: This pellicle consists of a pellicle film 1, frame 2, and adhesive layer 6 in such a manner that the pellicle film 1 is adhered to the upper face of the frame 2 with an adhesive 5 or a good solvent of the pellicle film 1, that the adhesive layer 6 is formed on the lower face of the frame 2 and that the frame is adhered and fixed to an exposure master plate 3. The adhesion layer 6 is provided with an aeration filter 9 so that air can be passed between the inside and outside of the pellicle. Thereby, a sealed state in the frame 2 can be avoided and such a problem that the pellicle film 1 expands or sinks is avoided even when environmental conditions, especially the atmospheric pressure or temp. change.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure master on which a pattern is drawn (photomask, reticle in the present specification) when performing lithography in the manufacture of semiconductor devices such as LSIs and VLSIs or liquid crystal display devices. And the like are collectively used in the description).

[0002]

2. Description of the Related Art In the manufacture of semiconductor devices such as LSIs and super LSIs or liquid crystal display devices, semiconductor devices such as silicon wafers or liquid crystal masters are used.
The pattern is transferred by irradiating light that has passed through the exposure master, that is, lithography is performed.If dust is attached to the exposure master, the dust absorbs light or bends the light. Therefore, the pattern transferred on the semiconductor wafer or the liquid crystal master becomes deformed, the edge becomes rough, and the white background is stained black, and the dimensions, quality, appearance, etc. are impaired, and as a result, The performance and manufacturing yield of semiconductor devices and liquid crystal display devices are reduced.

For this reason, lithography is usually performed in a clean room, but it is difficult to keep the exposure original plate completely clean even in the clean room. Therefore, as shown in FIG. 1, a pellicle 10 composed of a pellicle film 1 and a frame 2 is mounted on an exposure original 3. When the pellicle 10 is mounted on the exposure master 3 as described above, dust does not directly adhere to the exposure master 3 but adheres to the pellicle film 1, so that during lithography, the focal point is changed to a pattern on the image plane 4 of the exposure master 3. If they are matched, dust on the pellicle film 1 becomes irrelevant to the transfer.

When such a pellicle is viewed in more detail, as shown in FIG. 2, a pellicle film 1 is adhered to one end face (upper end face) of a frame 2 and the other end face (lower side) of the frame is provided. The pressure-sensitive adhesive layer 6 is provided on the end face). The pellicle film 1 is made of a material that allows light to pass well, for example, nitrocellulose, cellulose acetate, or the like. The frame 2 is made of, for example, aluminum, stainless steel, polyethylene, or the like, and the adhesive layer 6 is made of, for example, polybutene resin or polyacetic acid. It is made of vinyl resin, acrylic resin or the like.

The pellicle film 1 is bonded to the frame 2 by, for example, applying a good solvent for the pellicle film (see Japanese Patent Application Laid-Open No. 58-219023) or an adhesive 5 such as an acrylic resin or an epoxy resin on one end of the frame. (U.S. Pat.
No. 402, JP-B-63-27707)
It is done by applying. The pressure-sensitive adhesive layer 6 provided on the lower end surface of the frame 2 is covered with a protective sheet 7 for protecting the pressure-sensitive adhesive layer 6 until the pellicle is mounted on the exposure master. Further, an inner pressure-sensitive adhesive layer 8 may be provided inside the frame 2 for fixing dust.

When such a pellicle is mounted on an exposure master and used, the inside of the frame is in a sealed state. Therefore, when the atmospheric conditions, particularly the external pressure or the temperature, fluctuate, the sealed gas is released. There is a problem that the pellicle film expands and contracts due to expansion and contraction. In particular, when the pellicle film swells beyond a certain level, it comes into contact with other members in the apparatus, and the pellicle film is broken or normal lithography is not performed, causing a fatal problem.

[0007]

Various measures have been proposed as a method for preventing such swelling of the pellicle film. A typical method is to provide ventilation to the side of a frame on which the pellicle film is stretched. Are provided, and the pores are further covered with a filter from the outside (see JP-B-63-393703).

However, in such a method, it is necessary to perform a process of providing a hole in a frame, which is usually a metal such as aluminum, and such a process is troublesome.
It is difficult to clean the inside of the pores, resulting in insufficient cleaning and a new source of dust. Further, the pores must be covered with a filter from the outside. However, since the entire filter is exposed, there is a problem that it is difficult to clean the filter and it becomes a new dust generation source.

Therefore, the present invention has been made in view of such problems, and there is no fear of dust generation, and the pellicle film swells and breaks even if the atmospheric conditions such as the external pressure or the temperature fluctuate. It is an object of the present invention to provide a pellicle for lithography having air permeability, which does not cause problems such as the above.

[0010]

In order to solve the above-mentioned problems, the invention described in claim 1 of the present invention comprises at least a pellicle film, a frame for bonding the pellicle film, and a pellicle on the lower end surface of the frame. A pellicle for lithography, comprising: a pellicle for lithography having a pressure-sensitive adhesive layer for pressure-sensitive adhesion to an exposure master, wherein a filter for ventilation is provided in the pressure-sensitive adhesive layer.

If the ventilation is provided by providing a ventilation filter in the pressure-sensitive adhesive layer as described above, the problem of dust generation from the pores does not occur unlike the case where the frame is provided with the pores. The exposed portion can be minimized, and dust from the filter itself can be eliminated. Since the ventilation is performed through the filter, there is also an advantage that dust is not brought into the pellicle from outside due to the ventilation.

In this case, the ventilation filter provided in the pressure-sensitive adhesive layer may be provided on a part of the lower end surface of the frame or on the entire surface. Although it is better to be as small as possible from the viewpoint of cleanliness, it is preferable to provide it on the entire surface in order to quickly respond to changes in atmospheric conditions.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments. Here, FIG. 3 is an enlarged sectional view showing an example of the pellicle for lithography according to the present invention.

As shown in FIG. 3, the pellicle for lithography of the present invention comprises at least a pellicle film 1 and
Frame 2 having an adhesive layer 6
A pellicle film 1 is adhered to the upper end surface of the substrate by using an adhesive 5 or a good solvent for the pellicle film, and a pressure-sensitive adhesive layer 6 is provided on the lower end surface.

The pellicle film 1 is made of a material that allows light to pass well, for example, nitrocellulose, cellulose acetate, etc., the frame 2 is made of aluminum, stainless steel, polyethylene, etc., and the adhesive layer 6 is made of, for example, polybutene resin. Made of polyvinyl acetate resin, acrylic resin or silicone resin.

The pellicle film 1 is bonded to the frame 2 by, for example, applying a good solvent for the pellicle film or an adhesive 5 such as an acrylic resin or an epoxy resin to the upper end surface of the frame. May be provided with an internal pressure-sensitive adhesive layer for fixing dust. The configuration up to this point is the same as that of the conventional pellicle for lithography.

In the pellicle for lithography of the present invention, a ventilation filter 9 is provided in an adhesive layer 6 for adhesively fixing the pellicle on the lower end surface of the frame to the exposure original plate 3. And this ventilation filter 9
This allows the inside of the pellicle and the outside air to be ventilated, so that the sealed state in the frame is eliminated and the pellicle membrane bulges or dents even if the atmospheric conditions, especially the atmospheric pressure or temperature, fluctuate. The problem of slipping can be substantially solved.

The material of the filter 9 is not particularly limited as long as it is air-permeable and does not generate dust, but a fluorine-based, polyamide-based, or cellulose-based porous resin can be used. The pore size of the filter is desirably about 0.1 to 5 microns so as to prevent the passage of submicron-level dust, which is a problem in lithography. However, if it is too fine, it takes a long time for ventilation.

The method for providing the filter 9 on the pressure-sensitive adhesive layer 6 is not particularly limited. For example, as shown in FIG. 3, the filter 9 is sandwiched in the middle of the pressure-sensitive adhesive layer 6 and the end of the filter 9 is The filter can be installed so that the filter end protrudes slightly so as not to be covered by the filter.
In this case, needless to say, the filter 9 must be provided so as to penetrate the outer surface and the inner surface of the frame 2, but it is necessary to minimize or eliminate the protrusion to the inner and outer surfaces of the frame. Desirable from the point of view.

The position where the filter 9 is sandwiched is not necessarily required to be at the middle of the pressure-sensitive adhesive layer, but may be at the upper end or lower end of the pressure-sensitive adhesive layer. The number of layers is not limited, and a plurality of layers may be provided.
In this case, the thickness of the filter is 0.1 to 0.3 in total.
It is desirable that the thickness be about mm in order to secure air permeability and prevent dust generation.

The filter provided in the pressure-sensitive adhesive layer may be provided on the entire lower surface of the frame, or may be provided on a part thereof. That is, when the frame is rectangular, it may be provided on all four sides of the frame, or may be one side or a part of one side. In this case, from the viewpoint of cleanliness, it is better to be as small as possible, but from the viewpoint of air permeability, it is preferable to provide it on the entire surface in order to quickly respond to changes in atmospheric conditions.

To install the filter 9 in the pressure-sensitive adhesive layer 6, first, a thin pressure-sensitive adhesive layer is formed on the lower end surface of the frame 2, and then the filter 9 is set thereon, and the pressure-sensitive adhesive layer is further provided thereon. The thickness may be adjusted to a predetermined thickness.

If the pressure-sensitive adhesive layer is provided with a ventilation filter to allow ventilation, the exposed portion of the filter has a thickness of about 0.1 to 0.3 mm. Since it can be minimized, dust from the filter itself can be almost eliminated. Since the ventilation is performed through the filter, dust is not brought into the pellicle from outside due to the ventilation.

[0024]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples. (Example) Outside dimensions are 122 mm x 149 mm, width is 2 m
An aluminum frame having a height of 5.8 mm and an alumite-treated surface was prepared. A fluorinated polymer thin film was stretched as a pellicle film on the upper end surface of this frame via an adhesive. Next, as a pressure-sensitive adhesive layer, a silicone pressure-sensitive adhesive, KR-120 [manufactured by Shin-Etsu Chemical Co., Ltd.]
Was applied using a dispenser to a thickness of 0.2 mm, and dried at 120 ° C. for 3 minutes.

Next, a filter made of polytetrafluoroethylene having a hole diameter of 3 μm, a thickness of 0.2 mm, a width of 1 mm larger than the frame width, and a length of 3 mm and a length of 100 mm is used as a filter. Set to Then, the above-mentioned silicone-based pressure-sensitive adhesive is further applied thereon so as to have a thickness of 0.1 mm, dried at 120 ° C. for 3 minutes, and placed in a pressure-sensitive adhesive layer having a structure substantially similar to that of FIG. A pellicle for lithography having the following was produced.

After the pellicle for lithography finished in this manner is pressed and adhered to the original exposure plate at 30 kg for 3 minutes, the pressure is reduced from normal pressure to ／ pressure over 30 seconds. The time required for the swelling to completely disappear and return to its original state was measured. As a result, a problem such as breakage of the pellicle film does not occur, and the film returns to the original flat film in 25 minutes.
It was confirmed that the air permeability of the filter was sufficiently ensured and there was no practical problem.

Next, the pellicle for lithography is similarly adhered to the original plate by exposure to pressure at 30 kg for 3 minutes, and then the pressure is reduced from normal pressure to 2/3 atmosphere over 30 seconds, and the pressure is reduced for 5 minutes. Thereafter, the pressure was increased again to normal pressure for 30 seconds. After such operation was repeated 5 times, the foreign matter in the pellicle was visually measured using a 300,000 lux condensing lamp. As a result, no foreign matter was found, and the particle level did not differ between before and after the test. I was not able to admit.

The present invention is not limited to the above embodiment and examples. The above embodiments and examples are mere examples, and any one having substantially the same configuration as the technical idea described in the claims of the present invention and exerting the same function and effect will be described. However, they are also included in the technical scope of the present invention.

[0029]

As described above, according to the present invention, since the ventilation filter is provided in the pressure-sensitive adhesive layer of the pellicle for lithography, the pellicle film swells and breaks even if the atmospheric conditions such as the external pressure or the temperature fluctuate. There is no such a problem. In addition, since the portion where the filter is exposed can be minimized, dust from the filter itself can be eliminated. Further, since the ventilation is performed through the filter, there is an advantage that dust is not brought into the pellicle from outside due to the ventilation. Therefore, the utility value of the present invention in the industrial world is extremely high.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state where a pellicle is mounted on an exposure master.

FIG. 2 is a cross-sectional view of a conventional pellicle.

FIG. 3 is an enlarged sectional view showing an example of a pellicle for lithography of the present invention.

[Explanation of symbols]

1 ... pellicle film, 2 ... frame, 3 ... exposure master, 4 ... imaging surface, 5 ... adhesive,
6 ... adhesive layer, 7 ... protective sheet,
8: internal pressure-sensitive adhesive layer, 9: filter for ventilation,
10 ... pellicle.

Claims (2)

[Claims] 1. A lithographic pellicle having at least a pellicle film, a frame to which the pellicle film is adhered, and an adhesive layer for adhesively fixing the pellicle on the lower end surface of the frame to an exposure master. A pellicle for lithography, comprising a layer provided with a ventilation filter. 2. The pellicle for lithography according to claim 1, wherein the ventilation filter is provided on a part or the whole of a lower end surface of the frame.