HK1115835B - Method of applying film adhesive to pellicle frame - Google Patents

Description

Method for coating film binding agent on protective film frame

Technical Field

The present invention relates to a method for manufacturing a pellicle for lithography used as a dust catcher in the manufacture of objects such as semiconductor devices, printed circuit boards, and liquid crystal displays, and more particularly to a method for coating and forming a pellicle bonding layer on a pellicle frame.

Background

In the manufacture of semiconductor such as LSI and super LSI or products such as liquid crystal display panels, a semiconductor wafer or a liquid crystal original plate is irradiated with light to form a pattern, and if dust adheres to a photomask or a reticle (hereinafter simply referred to as photomask) used at this time, the dust absorbs the light to bend the light, so that the transferred pattern is deformed and the edge is roughened, and the substrate is stained black to deteriorate the size, quality, appearance, and the like.

Therefore, these operations are usually performed in a clean room, but even so often it is difficult to keep the photomask clean. Then, a pellicle for dust prevention is attached to the surface of the photomask, and then exposure is performed. At this time, the foreign matter is not directly attached to the surface of the photomask but attached to the pellicle, so that the foreign matter on the pellicle does not affect the transfer as long as the focus is aligned with the photomask pattern in the photolithography step.

In general, the pellicle is formed by forming a transparent pellicle film from a substance having good light transmittance, such as nitrocellulose, cellulose acetate, or fluororesin, forming a pellicle frame from a substance such as aluminum, stainless steel, or polyethylene, and adhering the pellicle to the upper end surface of the pellicle frame. Next, an adhesive layer made of polybutylene resin, polyvinyl acetate resin, acrylic resin, or the like, which is attached to the photomask, and a release layer (spacer) for protecting the adhesive layer are provided at the lower end of the pellicle frame.

In a small pellicle for semiconductor use, since the width of the pellicle bonding surface of the pellicle frame is narrow, about 1.5 to 2mm, the application of the pellicle adhesive is not difficult. However, since the frame width (film-bonding surface width) of the pellicle can be as wide as 10mm or more in a large pellicle for liquid crystal applications, it is difficult to apply the pellicle adhesive to the uncoated surface. In addition, since the width of the pellicle frame (width of the film-bonded surface) is largely different between the long side and the short side of the pellicle unit used for liquid crystal applications, and this is more difficult to achieve, there is a known technique of providing the frame with chamfers having different sizes so that the widths of the film-bonded surfaces are equal to each other (see patent document 1). However, providing too large a chamfer on the pellicle frame may reduce rigidity, and is therefore not preferred.

The simplest method of applying the entire width of the film-joining surface of the frame of the pellicle of the uncoated pellicle is to increase the amount of the coating liquid, but if the film-joining agent layer is made to have a thickness more than necessary, the appearance near the joining surface is impaired, and the height of the frame of the pellicle must be further reduced by the height of the portion having the increased thickness, which leads to a reduction in the frame rigidity. In particular, when the pellicle is attached in a soft state such as with a UV curable adhesive, the pellicle may protrude to the side surface of the pellicle frame. Further, the purpose of reducing the viscosity and increasing the amount of liquid can be achieved by increasing the amount of the solvent in the film-bonding agent solution, but since the amount of the solvent evaporated after application increases, the film-bonding agent aggregates during drying, and the flow becomes uneven due to the frame bending, conditions are limited, and the film-bonding agent cannot be applied without any problem.

Patent document 1: japanese laid-open patent publication No. 2001-109135

A general applicator is used for film-bonding agent application. FIG. 5 is a schematic view showing the application of a pellicle bonding agent to a film-bonding surface of a pellicle frame by an air pressure applicator. The liquid feeding mechanism may use a syringe pump, a plunger pump, a catheter pump, etc. in addition to air pressurization, and the parts other than the liquid feeding and liquid amount control methods are basically the same.

The syringe 53 is filled with a film-bonding agent solution, and the syringe 53 is pushed out from the discharge port 52 at the tip of the needle tube 51 attached to the syringe 53 by a pressure source such as air connected thereto. Then, the outlet 52 at the tip of the needle tube is moved while dropping the film bonding agent solution, and the entire periphery of the end face of the pellicle frame 54 is coated.

This system is a commonly used system, and has advantages of simple machine structure, easy management and storage, and easy discharge rate control.

The needle tube 51 is usually a needle catheter having a through hole at the center, and the film-bonding agent solution 55 continuously dropped from the tip of the needle tube 51 is expanded to form a film layer depending on the viscosity thereof, and the coating width thereof is spread rearward in the direction of the needle tube 51.

When the film bonding agent diffusion width is insufficient relative to the film bonding surface width, it is conceivable to provide a plurality of needle tubes 61 in the lateral direction relative to the needle tube advancing direction [ fig. 6(a) ]. However, in such a case, when the coating edge is changed and the advancing direction of the needle tube 61 is changed by 90 °, it does not matter that the needle tubes are arranged in parallel in the advancing direction.

Therefore, it is conceivable to provide a plurality of needle tubes 61 obliquely in the needle tube advancing direction as a corresponding measure (fig. 6 (b)). In this case, the needle tube 61 may be disposed on 2 vertical sides in the width direction. However, as shown in fig. 6(b), while the diagonal 2-corner portions A, C of a typical 4-sided protective film assembly can be suitably coated, the contiguous 2-corner portions B, D can result in a large sheet of uncoated portions 64. And 63 is a protective film frame.

In order to prevent such a problem, it is generally sufficient to add a mechanism for rotating the needle tube portion to the coating apparatus composed of an XY2 axis or XYZ3 axis vertical mechanism, but this is difficult to achieve because the apparatus cost increases and the liquid amount supply control becomes considerably complicated. When the corner portion is approaching, the rotation of the needle tube must be completed at the instant when the linear coating direction is changed by 90 °, and at this time, it is difficult to control the discharge amount of the coating liquid so that it does not overflow without being coated or being discharged too much in the case where the needle tube is rotated rapidly.

In addition, since the adhesive discharged from the plurality of needle tubes is condensed inside the needle tubes by the liquid surface tension, the adhesive cannot be diffused outside the frame width as expected.

When the width of the film-engaging surface of the pellicle frame is different, the film adhesive overflows without setting the space between the needle pipes to the narrowest width, and it is very difficult to prevent the film adhesive from being applied to both the narrow side and the wide side.

Further, as shown in fig. 6(c), when 4 needles 61 are arranged on both sides corresponding to the corner portions and the vertical direction without using a rotating mechanism, since the needle passing positions are overlapped in plural, the coating liquid 62 is distributed remarkably unevenly, and the corner portions are likely to have troubles such as non-coating or overflow.

As described above, a stable coating method has not been obtained so far, which can apply an appropriate amount of an adhesive to a pellicle frame, particularly a pellicle frame having a large width for use in liquid crystal applications, without causing the occurrence of non-application or overflow.

Disclosure of Invention

The present invention has been made in view of the above problems, and an object of the present invention is to provide a coating method capable of uniformly coating an appropriate amount of an adhesive on a wide pellicle frame without causing uncoated or overflow and forming an adhesive layer having an excellent appearance.

The method for coating a pellicle frame with a film bonding agent is to continuously drop the film bonding agent from a discharge port while moving the discharge port for coating, and in this case, the outer diameter width of a coating head provided with the discharge port is within the range of 60-120% of the width of the pellicle frame film bonding surface.

In addition, when the width of the film bonding surface of the pellicle frame is different between the long side and the short side, the width of the coating head in one direction is preferably in the range of 60 to 120% of the width of the long side, and the width of the coating head in the direction perpendicular to the long side is preferably in the range of 60 to 120% of the width of the short side, and the coating head is preferably moved so that the outer diameter corresponding to the width of the long side is perpendicular to the moving direction of the coating head when the long side is coated, and the outer diameter corresponding to the width of the short side is perpendicular to the moving direction of the coating head when the short side is.

Then, the coating head is preferably provided with a discharge port at the center of the tip and has a convex shape with the center portion as the apex.

In this case, the convex shape is preferably formed by one or more curved surfaces.

Then, the gap between the top of the applicator head and the surface of the pellicle frame during application is preferably 1.5mm or less, and the surface of the applicator head is preferably controlled by capillary phenomenon so that 80% or more of the surface of the applicator head is maintained in contact with the adhesive solution. The coating film bonding agent can be coated stably and can not be coated.

According to the present invention, even if a protective film frame having a film bonding surface with a large width, a protective film frame having a film bonding surface with a long side and a short side having different widths, and a protective film frame having a shape other than 4-square are coated with an appropriate amount of an adhesive uniformly and stably, and no occurrence of uncoated or overflow occurs, a film adhesive layer with a good appearance can be formed.

Drawings

Fig. 1 is a schematic view showing an embodiment of a tip structure of an applicator head provided with a discharge port according to the present invention, wherein (a) is a plan view and (b) is a cross-sectional view.

FIG. 2 is a schematic view showing an embodiment of the present invention applied to a pellicle frame having different widths of film-bonded surfaces on the long side and the short side, and is a cross-sectional explanatory view along the line A-A and the line B-B.

FIG. 3 is an explanatory view showing an embodiment of the mounting structure of the applicator head of the present invention, wherein (a) is a form in which the needle tube and the applicator head are integrally molded, and (b) is a form in which a pair of applicator heads are mounted to the tip ends of the needle tube, respectively, via bolts.

Fig. 4 is a schematic explanatory view of a film bonding agent application apparatus used in the present invention.

FIG. 5 is a diagram illustrating a conventional method for coating a pellicle frame with a film bonding agent using 1 needle tube.

Fig. 6 is an explanatory view showing a known method of coating a pellicle frame with a bonding agent using a plurality of needle tubes, wherein (a) 2 needle tubes are arranged in the lateral direction, (b) 2 needle tubes are arranged in the oblique direction, and (c) 4 needle tubes are arranged in a diamond shape.

Description of the reference numerals

11 coating head

12 discharge port

13 front end of coating head (vertex)

14 protective film frame

15 film binding agent solution

16 Syringe

21 coating head

22 discharge port

23 coating head front end

24 protective film frame

31 coating head (integral processing type)

32 Syringe

33 coating head (needle tube mounting type)

34 needle tube

35 mounting bolt

41 stand

42XYZ vertical 3-axis mechanical device

43 Syringe

44 protective film frame

51 needle tube

52 discharge opening

53 Syringe

54 protective film frame

55 film bonding agent

61 needle tube

62 film binding agent (coating liquid)

63 protective film frame

64 uncoated part

a coating head outer diameter width

b width of film bonding surface

c height difference between tip of coating head and outermost end in width direction

d distance between front end of coating head and surface of protective film frame

e coating head outer diameter width (Long axis)

f coating head outer diameter width (short axis)

Corner parts of A, B, C and D

Section line A-A, B-B

Direction of coating with big arrow

Detailed Description

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

Fig. 1 is a plan view and a schematic sectional view of an embodiment of a tip structure of an applicator head provided with a discharge port according to the present invention. FIG. 2 is a plan view and a cross-sectional schematic view of an embodiment of the present invention applied to a pellicle frame having different widths of film-bonded surfaces on the long side and the short side.

The applicator head 11 is attached to the tip of a syringe 16 filled with a film-bonding agent solution so as not to leak out of the liquid, and is movable in the horizontal plane and in the 3-axis directions perpendicular to each other by a moving mechanism (not shown) constituted by a mechanical device. The applicator head 11 moves on the pellicle frame 14 while dropping the film bonding agent solution 15 from the discharge port 12, and applies the film bonding agent to the frame around the film bonding surface 1 of the pellicle frame 14.

Here, various transfer mechanisms (not shown) capable of controlling the supply amount and the discharge stopping operation, such as a syringe pump, a plunger pump, and a catheter pump, may be used as the transfer mechanism of the film adhesive, in addition to gas pressurization such as air pressurization and nitrogen pressurization.

In this case, the outer diameter width a of the coating head 11 is preferably in the range of 60 to 120% of the film bonding surface width b of the pellicle frame 14. When the width of the film joining surface is different between the long side and the short side, as shown in the plan view of fig. 2, the width e of the coating head in one direction is formed within the range of 60 to 120% of the width of the long side, and the width f of the coating head in the direction perpendicular to the long side is formed within the range of 60 to 120% of the width of the short side, and the coating head is preferably moved so that the outer diameter e corresponding to the width of the long side in the long side coating is in the direction perpendicular to the moving direction of the coating head, and the outer diameter f corresponding to the width of the short side in the short side coating is in the direction perpendicular to the moving direction of the coating head.

In fig. 1, the gap between the tip 13 of the applicator head 11 and the pellicle frame 14 is filled with the film bonding agent solution discharged from the discharge port 12 by capillary action. As a result, even if the protective film frame has a large width, the film bonding agent can be continuously supplied to the outside, and the film bonding agent can be prevented from being left uncoated.

At this time, since the film bonding agent solution under the applicator head 11 is often coagulated by surface tension, the width a of the applicator head 11 is wider than the film bonding surface width b, and even if the outer diameter portion moves outside the film bonding surface, the film bonding agent does not drip outside as long as the amount does not exceed the limit. On the contrary, even if the outer diameter width a of the applicator head 11 is smaller than the film bonding surface width b, the surface can be coated without omission by the viscosity of the film bonding agent used.

Therefore, the viscosity (concentration) of the film bonding agent and the specification of the coating head 11 are appropriately determined in consideration of factors such as the width of the film bonding surface of the pellicle frame, the film thickness after drying, and the appearance.

Similarly, the outer diameter width of the coating head 11 is appropriately determined within a range of 60 to 120%, particularly preferably 80 to 100%, of the film bonding surface width in consideration of factors such as the film bonding surface width, the film bonding agent viscosity, and the distance between the coating head and the film bonding surface. The applicator heads 21 having different longitudinal and lateral outer diameters shown in fig. 2 can be manufactured by first preparing a circular object corresponding to the side having a larger diameter and then performing planar cutting in one direction, thereby obtaining a desired shape, and the manufacturing is most convenient and practically not hindered.

The coating head 11 is preferably provided with a discharge port 12 at the center of the tip and is formed in a convex shape with the center as the top. Further, the convex shape is preferably formed by one or more curved surfaces.

The discharge port is provided in the center portion, so that the application condition can be stabilized regardless of which of the 2 sides perpendicular to each other is applied, and the tip droplet is stabilized before application because the discharge port is provided in the top portion, and the discharge port is not easily dried.

The shape of the tip 13 of the applicator head 11 can be applied even in a substantially planar shape, but if the corner portion is stably applied without making the joint between the start point and the end point of application conspicuous, only the convex effect is preferable.

In addition, the convex shape is preferably formed in a curved surface shape, particularly a curved surface of a rotating body, and in this case, the film bonding agent between the coating head and the film bonding surface is relatively stable in the film bonding agent coating, and the coating effect is optimal. It is relatively easy to make the curved surface with a constant curvature, but several curved surfaces may be used in combination if necessary.

The height difference c between the apex and the outermost end in the width direction is appropriately determined in consideration of factors such as the viscosity of the film bonding agent, the relationship between the outer diameter width a of the applicator head 11 and the film bonding surface width b, and is preferably approximately in the range of 0.3 to 1 mm. Further, in order to adjust wettability (contact angle) between the tip 13 of the coating head 11 and the film bonding agent, surface processing treatment may be performed.

The gap d between the tip (top) 13 of the applicator head 11 and the surface of the pellicle frame 14 during application is preferably 1.5mm or less, and at the time of application, 80% or more of the applicator head surface 13 is preferably held in contact with the film bonding agent solution 15 by the capillary phenomenon as described above. In this way, the center portion of the pellicle frame usually sags downward due to its own weight, and therefore, it is necessary to support the portion from below to above so as to keep it horizontal. In this case, the film bonding agent can be prevented from flowing and becoming uneven after coating, and the film bonding agent can be gradually dried in a flat and good-looking state, which has a double effect.

It is needless to say that it is important to stabilize the discharge amount of the film bonding agent during coating and the moving speed of the coating head. Such a state is always maintained in coating, and it is important for good coating.

The applicator head may be integrally molded as shown by 31 in fig. 3(a), or may be attached to the tip of a normal needle tube 34 by a member such as a bolt 35 as shown by 33 in fig. 3 (b). And 32 denotes a syringe.

The material of the coating head is preferably a metal such as carbon steel, stainless steel, brass, or a material having resistance to a solvent for the binder such as PTFE (tetrafluoroethylene), and it takes a lot of time to form fine holes with high precision and smoothness by processing the material. Therefore, the discharge port portion shown in fig. 3(b) is a preferable option from the viewpoint of industrial production when a separate member is manufactured by using commercially available needle tubes and assembling them, as compared with the object integrally molded as shown in fig. 3 (a).

Examples

Hereinafter, examples of the present invention will be described, but the present invention is not limited thereto.

Example 1

First, a rectangular aluminum alloy protective film frame having an outer dimension of 1146X 1366mm, an inner dimension of 1122X 1342mm, a height of 6mm, a corner inner dimension of R2, an outer dimension of R6mm and a film joining face width of 12mm was manufactured by machining, and after sand blasting was performed with SUS fine beads to have an Ra of about 0.8 to 0.9, black alumite treatment was performed on the surface. The pellicle frame was carried into a class 1 clean room, washed thoroughly with a neutral detergent and pure water, and dried, and then subjected to a test of coating a film adhesive on the end face.

FIG. 4 is a schematic view of a film bonding agent coating apparatus used in the present invention. A gate-type XYZ vertical 3-axis mechanism 42 is attached to the mount 41, and a PP syringe 43 is attached to the Z-axis tip thereof.

The PP syringe 43 is connected to an air pressure applicator (IEI), not shown, and controls the operation of the 3-axis mechanical device 42 and the discharge operation of the coating liquid by a control unit. Then, the pellicle frame 44 of the above-described specification was fixed to the apparatus in such a manner that the adhesive-coated end face was kept horizontal upward. Further, in order to prevent the pellicle frame 44 from being bent by its own weight and to keep the film joining surface horizontal, support portions made of POM resin are provided at intervals of about 200mm on each side of the lower surface of the pellicle frame.

Then, the syringe 43 was filled with a silicone adhesive (trade name: X-40-3004A, manufactured by shin-Etsu chemical Co., Ltd.) diluted to 15% with toluene as a film-bonding agent solution.

The applicator head 11 having the shape shown in fig. 1 is attached to the tip of the syringe 43. The coating head 11 is made of brass by machining, and the surface thereof is plated with a layer of nickel for rust prevention. A tube of SUS304 was machined into the larger diameter opening at the discharge port 12.

The outer diameter a of the applicator head 11 was set to 12mm similarly to the width b of the bonding surface of the pellicle frame 14, the shape of the tip 13 was a spherical surface with a curvature R30, and the diameter of the discharge port 12 was 0.3 mm. In addition, the gap between the front end 13 of the coating head 11 and the surface of the pellicle frame 14 in coating is set to about 0.8 mm.

Then, the coating of the film-bonding agent is performed by automatic operation until the film-bonding agent does not flow when air-dried. Thereafter, the pellicle frame was heated to 120 ℃ by a high-frequency induction heating apparatus (not shown), the solvent was completely dried, and the adhesive was completely cured.

The test sample thus prepared was transferred to a darkroom, and the appearance of the film-bonding agent-coated surface was observed with a halogen lamp having a light amount of 30 ten thousand lux. As a result, the film-bonded end face was completely coated with the film bonding agent, and no uncoated portion was found at the corner portion. The film bonding agent applied to the inner surface, the outer surface and the chamfered portion of the pellicle frame was not found to have overflowed. Furthermore, the surface became a smooth surface with a gloss without any curved undulations or deviations, and the appearance looked quite good.

Example 2

First, a rectangular aluminum alloy protective film frame having an outer dimension of 436 × 745.5mm, an inner dimension of 418 × 734.5mm, a height of 6mm, a corner inner dimension of R2mm, an outer dimension of R9mm, a long side width of 9mm and a short side width of 5.5mm at a film joining surface was produced by machining, and subjected to a sand blast treatment using SUS fine beads to a level of about ra0.8 to 0.9, and then subjected to a black alumite treatment on the surface. The pellicle frame was carried into a clean room of class 1, thoroughly washed with a neutral detergent and pure water, dried, and then subjected to a test in which a film adhesive was applied to the end face.

The same object as in example 1 above was used as a coating device, and only the coating head used was a member having a shape as shown in fig. 2.

The major axis outer diameter e of the applicator head 21 was 9mm, the minor axis outer diameter f was 5.5mm, the shape of the tip 23 was a spherical surface with a curvature R25mm, and the diameter of the discharge port 22 was 0.3 mm. In addition, the gap between the apex of the coating head 21 and the surface of the pellicle frame 24 in coating is set to about 0.8 mm.

Then, the same film bonding agent application and evaluation as in example 1 were carried out. As a result, no uncoated portion was found in the corner portion even when the short-side and long-side film-bonded end faces were completely coated with the film bonding agent. Further, no overflow was observed in the film bonding agent applied to the inner surface, outer surface, and chamfered portion of the pellicle frame. Furthermore, the surface became a smooth surface with a gloss without any curved undulations or deviations, and the appearance looked quite good.

Comparative example

The same pellicle frame and coating apparatus as in example 1 were used, and a member having a shape in which 2 needle tubes 61 were arranged as shown in FIG. 6(b) was used only for the outlet portion of the lower portion of the syringe, and the evaluation of coating with the film adhesive was performed.

Here, the material SUS304 of each needle, the inner diameter 0.25X the outer diameter 0.46mm, the distance between the needles 8mm, and the angle of the relative movement direction shift were 45 °.

Then, coating and evaluation of a film bonding agent were carried out in exactly the same manner as in examples 1 and 2. As a result, the meniscus-shaped uncoated portion 64 having a maximum width of about 2mm was found outside the corner B, D, and the uncoated portions extending in a long-line shape having a width of 0.5 to 1mm were found at several positions on the inner side edges of the long sides, and it was difficult to say that the coating quality was satisfactory.

Industrial applicability

According to the film bonding agent coating method of the present invention, the bonding agent can be uniformly, homogeneously, simply and reliably coated on the protective film attaching surface of the protective film frame without leaving an uncoated portion, and the method is of great benefit to the industrial field utilizing the photolithography technique.

Claims (5)

1. A method for coating a film bonding agent on the end face of a pellicle frame, characterized by:

coating is performed by moving the outlet while continuously dropping the film bonding agent from the outlet, wherein the outer diameter width of the cylindrical coating head provided with the outlet is in the range of 60-120% of the width of the pellicle frame,

and the coating head is provided with a discharge port at the center of the front end and is formed in a convex shape with the center part as the top.

2. The method for coating a film bonding agent to an end face of a pellicle frame according to claim 1,

when the width of the film bonding surface of the pellicle frame having the long side and the short side perpendicular to each other is different between the long side and the short side, the coating head is further provided with two parallel planes obtained by cutting the cylindrical surface on the outer periphery, wherein the width in one direction is set within the range of 60-120% of the width of the long side, the width in the direction perpendicular to the long side is set within the range of 60-120% of the width of the short side, the coating head is arranged and moved so that the outer diameter of the coating head corresponding to the width of the long side during long side coating is in the direction perpendicular to the moving direction of the coating head, and the outer diameter of the coating head corresponding to the width of the short side during short side coating is in the direction perpendicular to the moving direction of the coating head.

3. The method for coating a film bonding agent to an end face of a pellicle frame according to claim 1 or 2,

the convex shape of the front end of the coating head is formed by one or more curved surfaces.

4. The method for coating a film bonding agent to an end face of a pellicle frame according to claim 1 or 2,

the gap between the top of the coating head and the surface of the protective film frame is 1.5mm or less during coating, and the gap is controlled so that 80% or more of the surface of the coating head is maintained in contact with the adhesive solution by capillary phenomenon.

5. The method for coating a film bonding agent to an end face of a pellicle frame according to claim 3,

the gap between the top of the coating head and the surface of the protective film frame is 1.5mm or less during coating, and the gap is controlled so that 80% or more of the surface of the coating head is maintained in contact with the adhesive solution by capillary phenomenon.