HK1097053B - Pellicle frame - Google Patents

Description

Protective film frame

Technical Field

The present invention relates to a pellicle for lithography used as a dust remover in the manufacture of semiconductor devices, printed circuit boards, liquid crystal displays, or the like, and more particularly, to a large-sized pellicle used in the manufacture of liquid crystal displays.

Background

In the manufacture of semiconductor devices such as LSIs and liquid crystal displays, patterns are formed by irradiating a semiconductor wafer or a glass plate for liquid crystal with light, but if dust adheres to a photomask or reticle (hereinafter simply referred to as "photomask") used in this case, the dust blocks or diverts light, and there is a problem that the transferred patterns are damaged.

Therefore, the related work is usually performed in a clean room, but it is still difficult to keep the photomask clean at all times. Therefore, a method of attaching a pellicle on the surface of the mask as a dust remover is adopted.

At this time, since the foreign matter is not directly attached to the surface of the mask but is attached to the pellicle, the foreign matter on the pellicle does not affect the transfer printing as long as the pattern of the mask is focused during the lithography.

The pellicle is generally formed by coating a transparent pellicle film made of nitrocellulose, cellulose acetate, or a fluorine-based resin, which transmits light well, with a good solvent of the pellicle film, air-drying the film and then adhering the film (see patent document 1), or adhering an adhesive such as acryl resin or epoxy resin (see patent documents 2 and 3) to the upper end surface of a pellicle frame made of aluminum, stainless steel, polyethylene, or the like, and arranging an adhesive layer made of polybutene resin, polyvinyl acetate resin, acryl resin, or the like, which is intended for mounting a photomask, and a release layer (barrier layer) intended for protecting the adhesive layer, at the lower end of the pellicle frame.

In addition, in a state where the pellicle is attached to the photomask, for the purpose of eliminating a difference in air pressure between the space surrounded by the interior of the pellicle and the outside, small holes for air pressure adjustment are formed in a part of the pellicle frame, and a filter for the purpose of preventing intrusion of foreign matter due to air moving through the small holes is provided (see patent document 4).

In the manufacture of the pellicle assembly, the pellicle frame must be held during assembly and transportation, and as shown in fig. 6, a groove or recess 63 is generally provided on the outer surface of the pellicle frame, and a pin or the like is inserted for holding. Generally, 2 recesses are provided on each of the opposite 2 sides, for a total of 4. In this case, the concave portion 63 is usually disposed at a position approximately 20 to 30% of the side length of the frame from the corner portion 62 so that the vertical deformation is less likely to occur when the pellicle frame is held by a pin or the like.

When the pellicle is attached to the photomask and needs to be replaced for some reason, it needs to be peeled off. In this case, the peeling can be performed by a method in which a plate-shaped jig is inserted into the shield adhesive layer to lift the frame upward, or a method in which a pin-shaped jig 54 is inserted into the recess 52 provided on the outer surface of the pellicle frame as shown in fig. 5(a) and (b), and the pellicle frame 51 is lifted upward by the lever principle to peel, or the like.

When the plate-like jig is inserted into the shield adhesive layer, the jig can be inserted from the entire circumference of the pellicle frame, and therefore, there is an advantage that peeling can be performed sequentially from the easily peeled end.

On the other hand, in the method of inserting the pin-shaped jig into the recess disposed on the outer surface of the pellicle frame, the risk is less likely to occur. However, as described above, only the recess at 4 is generally provided, and the position thereof is also a position where application to peeling is not taken into consideration. Therefore, in the case of a large pellicle having a side length of more than 500mm, since the peeling area at one time is large, there is a problem that a large force is required for peeling.

In addition, while the pellicle frame is lifted up by the peeling jig, the pellicle frame is deformed, or a part of the periphery of the pin is peeled off and lifted up, but after the peeling jig is removed, the pellicle frame returns almost to the original position, and most of the pellicle frame is adhered again. As a result, there arises a problem that it is extremely difficult to peel off the entire pellicle assembly.

[ patent document 1 ] Japanese patent laid-open publication No. Sho 58-219023

[ patent document 2 ] specification of U.S. Pat. No. 4861402

[ patent document 3 ] Japanese examined patent publication No. 63-27707

[ patent document 4 ] Japanese Kokoku publication Sho 63-39703

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide a large pellicle frame that can be easily peeled off after being attached to a photomask, and a pellicle for photolithography using the pellicle frame.

In order to solve the above problems, in a large pellicle frame of the present invention, the length of the long side of the frame is 500mm or more, at least 1 concave portion is provided on the outer side surface within 50mm near the corner portion.

The entire outer surface of the pellicle frame should be provided with 5 or more recesses, and the recesses should be round holes with a diameter of 1.0mm to 3.0mm and a depth of 0.5mm or more.

Then, the pellicle frame is used to form a pellicle assembly.

According to the present invention, even in a large pellicle having a long side length of more than 500mm, since the recessed portion is provided at a position within 50mm of the corner portion, when peeling from the photomask substrate, peeling can be started from the corner portion, and therefore the force required for peeling is small, and further, the pellicle frame in the vicinity of the corner portion is turned upward from the outer periphery to the inner side of the corner portion and is plastically deformed so as not to be easily re-adhered, so that peeling is extremely easy. In addition, even in the case of an oversized pellicle with a side length exceeding 700mm, the pellicle can be easily peeled off because a part of the pellicle can be peeled off in a stepwise manner by using a recess disposed not in the vicinity of the corner.

Drawings

FIG. 1 is a diagram illustrating an embodiment of a pellicle frame according to the present invention.

Fig. 2 is a schematic explanatory view of a state where the pellicle frame of the present invention is peeled from a glass substrate.

FIG. 3 is a sectional view illustrating a recess portion provided in the pellicle frame of the present invention.

FIG. 4(a) is a diagram illustrating another embodiment of the pellicle frame of the present invention.

FIG. 4(b) is a diagram illustrating still another embodiment of the pellicle frame of the present invention.

Fig. 5(a) is a schematic explanatory view of a state where the pellicle is peeled off by the peeling jig, and is a state where peeling is started.

Fig. 5(b) is a schematic explanatory view of a state where the pellicle is peeled off by the peeling jig, and is a state where the pellicle is being peeled off.

Fig. 6 is an explanatory view of an example of a conventional pellicle frame.

Fig. 7 is a schematic explanatory view of a state where a conventional pellicle frame is peeled from a glass substrate.

Description of the main Components

11 frame of protective film

12 corner

13 recess

14 Shield adhesive layer

15 Quartz glass substrate

16 protective film diaphragm

17 protective adhesive film sheet adhesive layer

21 pellicle frame

22 corner

23 (near corner) recess

24 (additional) recesses

31 pellicle frame

32 corner

33 recess

34 concave part

51 pellicle frame

52 recess

53 Quartz glass substrate

54 peeling clamp

55 Shielding adhesive layer

61 protective film frame

62 corner

63 recess

64 Shield adhesive layer

65 quartz glass substrate

66 (the pellicle frame is deformed by peeling)

Detailed Description

The embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited thereto.

Fig. 1 is an explanatory view of an embodiment of a pellicle frame of the present invention, fig. 2 is a schematic explanatory view of a state in which the pellicle frame of the present invention is peeled from a glass substrate, fig. 3 is a sectional view for explaining a recess portion provided in the pellicle frame of the present invention, fig. 4(a) is an explanatory view of another embodiment of the pellicle frame of the present invention, fig. 4(b) is an explanatory view of still another embodiment of the pellicle frame of the present invention, fig. 5 is a schematic explanatory view of a state in which a pellicle assembly is peeled by a peeling jig, fig. 5(a) is a state in which peeling is started, and fig. 5(b) is a state in which peeling is being performed.

In FIG. 1, a recessed portion 13 is provided in a portion of the longer side of the pellicle frame 11 within 50mm near the corner portion 12.

Therefore, when peeling is performed by inserting a peeling jig such as a pin into the recess 13, peeling is started from the corner as shown in fig. 2, and therefore, a force required for peeling is small, and further, the pellicle frame is plastically deformed upward in the vicinity of the corner and is hard to adhere again, so that peeling is extremely easy. However, the position of the recess 13 must be within 50mm of the corner 12, and if the distance is longer than or equal to this, the peeling force required for peeling increases significantly, and it is difficult to completely peel off the corner, and the desired effect cannot be obtained.

Conventionally, such recessed portions are provided at 2 on opposite sides for holding, and positioning is performed with attention paid to load balance, and generally at 4 positions, however, in the present invention, in addition to the recessed portions originally intended for holding the pellicle frame, the recessed portions are additionally provided at positions where peeling is taken into consideration, or only the recessed portions taking peeling into consideration are arranged at all, and peeling can be performed more easily.

The recess is a circular hole having a diameter of 1.0mm or more and 3mm or less and a depth of 0.5mm or more. In the conventional recess, since the holding is focused on, the holding tool may be engaged with the recess, and the diameter and depth thereof are not necessarily suitable for the peeling jig.

Secondly, if the pellicle is constructed by using such a pellicle frame, it is very easy to peel the pellicle from the mask.

In this embodiment, the concave portion 13 is disposed near the corner portion 12 on the long side, but may be disposed on the short side. In addition, the sheet may be disposed on both the short side and the long side (fig. 4 (b)). Further, a concave portion for holding the pellicle frame and a concave portion for peeling may be separately provided (fig. 4 (a)).

Fig. 3 is a cross-sectional view of a shape of the concave portion, and the cross-section is substantially circular. Since the pin is circular, it is easy to process and can be fitted well to a circular pin which is generally used. In addition, a depth of 0.5mm or more is preferable in consideration of sufficient fitting with a pin used for holding or peeling.

The diameter should be 1mm or more and 3mm or less, preferably 2 to 2.5 mm. If the thickness is 1mm or less, it is difficult to maintain the strength of the pin used for holding or peeling, and the strength required for holding and peeling with good accuracy cannot be satisfied. In addition, when the thickness is 3mm or more, the amount of the defect of the pellicle frame increases, which causes a problem of strength in use, and also causes a problem that the periphery of the recessed portion is likely to be curled or damaged during peeling, thereby making peeling difficult. In addition, the shape of the bottom of the hole (concave part) can be maintained as shown in the figure, and the shape of the front end of the drill bit can also be modified into a spherical surface or a plane surface.

Generally, although machining is easy if all the recesses have the same size and shape, optimization of each place should be sought, for example, in consideration of ease of insertion of the pin depending on the position and the application.

Fig. 4(a) shows another embodiment, in which a plurality of other recessed portions 24 are provided inside the recessed portion 23 in the vicinity of the corner portion 22. In fig. 4b, the concave portions 34 are provided on both the long side and the short side (additional side). According to this configuration, when the side length of the oversized pellicle frame exceeds 700mm, the pins can be inserted from the corners in sequence and then the pellicle frame can be peeled off gradually, so that the pellicle frame can be peeled off from the photomask more easily.

As described above, in the present invention, the recessed portion is provided in the vicinity of the corner portion on the outer side of the conventional pellicle frame, in consideration of the position of the pellicle frame deformed downward. Therefore, when the pellicle frame is held by the pins, the pellicle frame may be deformed downward by its own weight, but the use of the holes of 4 or more positions as shown in the above embodiment prevents the above-mentioned situation, and the means for providing the lower support in the manufacturing apparatus can be easily corrected.

[ example 1 ]

The following description will be made of examples of the present invention, but the present invention is not limited thereto.

The pellicle frame 11 made of aluminum alloy having the shape shown in fig. 1 was fabricated by machining. The pellicle frame 11 is rectangular in shape having an outer dimension of 782 × 474mm, an inner dimension of 768 × 456mm, and a height of 5 mm. The recesses 13 are located at positions spaced apart from the corner 12 of the long side surface by 36mm, and are arranged at 4 positions in total on the opposite side surfaces, and have a shape of an unpenetrated circular hole having a diameter of 2.5mm and a depth of 2.5 mm.

After the pellicle frame was cleaned and dried, a silicone adhesive was applied to one end face as a pellicle film adhesive, and a silicone adhesive (product name: KR120, manufactured by shin-Etsu chemical industries, Ltd.) diluted to 50% with toluene was applied to the other end face as a masking adhesive, followed by baking with heating.

Further, a thin film of a fluorine-based polymer (trade name: CYTOP, manufactured by Asahi glass (Strand) glass) was formed on a rectangular quartz substrate having a thickness of 800X 920X 8mm by a spin coating method, and the film was adhered to a frame having the same shape as the substrate, and peeled off to obtain a pellicle film having a thickness of about 4 μm, and then the pellicle film was attached to the pellicle frame. Then, the unnecessary film around the pellicle frame is cut off by a cutter to form a pellicle assembly. The cross-sectional configuration of the periphery of the recess of the completed pellicle is shown in FIG. 3.

After the completed pellicle 51 was attached to a smooth quartz glass substrate 53 of 520 × 800mm × 8mm in thickness with a load of 120kg as shown in fig. 5(a), a peeling test from the quartz glass substrate 53 was performed by inserting a peeling jig 54 into the recess 52.

As a result, in the case of the operation of the peeling jig 54, as shown in fig. 2 and 5(b), the corner portions can be completely peeled off, and when the peeling operation is performed on all of the 4 recesses, only the central portions of the sides of the pellicle frame cannot be peeled off and remain. And then, directly grasping the protective film frame by hands, and slowly pulling up the protective film frame, so that the quartz glass substrate can be completely stripped.

[ example 2 ]

The pellicle frame 21 made of aluminum alloy having the shape shown in fig. 4(a) was fabricated by machining. The pellicle frame 21 was rectangular in shape having an outer dimension 782 × 474mm, an inner dimension 768 × 456mm, and a height of 5mm, as in example 1. Here, the recessed portions are located at positions 36mm apart from the corner portions 22 of the long side surfaces, respectively, and are arranged at 4 places (23), and next, at positions 166mm apart from the corner portions 22, are arranged at 4 places (24), respectively, and are in the form of non-penetrating circular holes 2.5mm in diameter and 2.5mm in depth. Next, the pellicle frame 21 was cleaned and dried, and then trimmed to form a pellicle assembly by the same procedure as in example 1.

The completed pellicle was attached to a smooth quartz glass substrate of 520X 800mm X8 mm in thickness with a load of 120kg, and then the same peeling test from the glass substrate as in example 1 was performed from the corner. As a result, the pellicle frame can be easily lifted up by the operation of the peeling jig 54, and thereafter, the entire pellicle frame can be completely peeled off by sequentially performing the same operation for the adjacent concave portions, and a part of the pellicle frame comes into contact again to be in an extremely slightly adhesive state. Then, the pellicle frame is directly held by hand and slowly pulled upward, so that the pellicle frame can be easily peeled off from the glass substrate.

[ COMPARATIVE EXAMPLE ]

The pellicle frame 61 made of aluminum alloy having the shape shown in fig. 6 was fabricated by machining. The pellicle frame 61 was rectangular in shape having an outer dimension 782 × 474mm, an inner dimension 768 × 456mm, and a height of 5mm, similar to those of example 1. The recesses 63 are located at positions spaced from the corner portions 62 of the long side surfaces by 170mm, and are arranged at 4 positions in total, and have a shape of an unpenetrated circular hole having a diameter of 2.5mm and a depth of 2.5 mm. Next, the pellicle frame 61 was cleaned and dried, and then trimmed to form a pellicle assembly by the same procedure as in example 1.

The completed pellicle was attached to the quartz glass substrate in the same manner as in the above example, and a peel test was performed. In addition, as shown in fig. 7, the pellicle frame 61 on the outer periphery of the recessed portion 63 slightly floats upward to form a gap 65, and thus the region other than the outer periphery of the recessed portion 63 cannot be peeled. Next, the pellicle frame 61 cannot be lifted up by the jig any more, and is in a state in which it cannot be further peeled off.

According to the invention, when the photomask and the protective film assembly need to be stripped, the stripping can be carried out easily, conveniently and safely with small force, so that the protective film assembly has high utilization value in the technical field of lithography utilizing the protective film assembly.

Claims (3)

1. A pellicle frame has a long side length of 500mm or more,

at least 1 recess is provided on the outer surface within 50mm in the vicinity of the corner, and the recess is an unpenetrated circular hole having a diameter of 1.0mm or more and 3.0mm or less and a depth of 0.5mm or more.

2. A pellicle frame has a long side length of 500mm or more,

a total of 5 or more recesses are provided on the outer surface, and the recesses are round holes that do not penetrate and have a diameter of 1.0mm or more and 3.0mm or less and a depth of 0.5mm or more.

3. A pellicle frame according to claim 1 or 2, wherein the pellicle frame is formed of a pellicle frame.