JP2010217698A - Method of attaching thin film, and pellicle optical element manufactured by the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce defective surface precision of a thin film sheet after attachment in a method of attaching thin film and a pellicle optical element manufactured by the method of attaching thin film. <P>SOLUTION: The method of attaching thin film includes: a stretching step of stretching a resin base sheet 4 planarly by stretching the sheet along at least biaxial directions at least intersecting each other while holding the outer edge part of the resin base sheet 4; a flat surface forming member-pressing step of conforming the resin base sheet 4 to a film adhesion surface 2a by pressing a flat surface plate 16 having such a size as to cover a frame member 2 against the central part of the resin base sheet 4; a frame body-pressing step of pressing the frame member 2 against the resin base sheet 4 against which the flat surface plate 16 is pressed while facing an opening part of the frame member 2; an adhering step of applying an adhesive from the outer circumferential part of the frame member 2 and adhering the frame member 2 to the resin base sheet 4; and a thin film sheet cutting step of cutting the resin base sheet 4 adhered to the frame member 2 at the outer peripheral part of the frame member 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for attaching a thin film, and a pellicle optical element manufactured thereby.

Conventionally, a pellicle optical element in which a thin film with a half mirror coating on its surface is stretched around a frame as a beam splitter that can be made smaller and lighter than when glass plates and glass prisms are used. It has been known.
For example, Patent Document 1 describes a pellicle optical element in which a resin film (thin film) obtained by biaxially stretching a polyethylene terephthalate resin having a thickness of 23 μm is stretched around a rectangular frame made of a stainless steel metal.
In this method for manufacturing a pellicle optical element, a thin film is attached as follows.
First, the resin film is placed on a sticking holder having an opening larger than the rectangular frame by pulling from the center portion of the resin film in the outer peripheral direction. And a rectangular frame is arrange | positioned on the center part of a resin film, a weight is mounted on this rectangular frame, and a resin film is pressed. Thereby, the resin film is bent and stretched within the rectangular frame. In this state, an adhesive is applied and bonded from the outer periphery of the rectangular frame. And a resin film and an adhesive agent are heated and an adhesive agent is solidified. Thereafter, the resin film is cut at the outer periphery of the rectangular frame.
Then, a pellicle optical element is manufactured by coating the resin film fixed to the rectangular frame.

JP-A-9-319070

However, the conventional thin film attaching method as described above has the following problems.
In the technique described in Patent Document 1, since the rectangular frame is pressed against the resin film stretched in the opening of the attaching holder, if the pressing position and the pressing direction vary, the rectangular frame and the resin film The contact state of the is likely to vary. For example, when a pressing force is applied after placing a rectangular frame on a resin film, it is difficult to instantaneously apply a uniform pressing force to the entire rectangular frame, resulting in variations in the pressing start position and pressing start direction. To do. For this reason, uneven tension occurs in the resin film in the rectangular frame, and good surface accuracy cannot be obtained, or there is a gap of a size that allows the adhesive to flow out between the rectangular frame and the resin film. To do.
When such a gap occurs, the adhesive protrudes inward from the rectangular frame during solidification and solidifies, the stress distribution of the resin film in the rectangular frame is disturbed, and the surface accuracy is locally deteriorated. There is a problem that the optical properties of the resin film are impaired by the protrusion.
In addition, when the rectangular frame has a fine distortion, the resin film is bonded without correcting the distortion, so that there is a problem that the surface accuracy is deteriorated due to the distortion of the rectangular film. .
When the surface accuracy of the resin film is deteriorated, there is a problem that the wavefront aberration of light reflected by the pellicle optical element is deteriorated and good optical characteristics cannot be obtained with respect to the reflected light.

  The present invention has been made in view of the above problems, and a thin film attaching method capable of reducing surface accuracy defects of a thin film sheet after being attached, and a pellicle optical element manufactured thereby The purpose is to provide.

In order to solve the above-described problems, the thin film attaching method of the present invention is a thin film attaching method for attaching a thin film to an opening of a frame, and is formed in a sheet shape larger than the opening of the frame. The thin film sheet is held at the outer edge of the thin film sheet, and is pulled along at least two intersecting axial directions, whereby the thin film sheet is stretched in a planar shape, and the tension step is stretched. The flat surface forming member is pressed against the flat portion by pressing a flat surface forming member having a flat portion covering the frame at the central portion of the thin film sheet on the flat surface side. And a frame body pressing step of pressing the frame body with the opening facing the thin film sheet portion pressed against the flat surface portion by the flat surface forming member pressing step. An adhesive step in which an adhesive is applied from an outer peripheral portion of the frame body pressed against the thin film sheet in the frame body pressing step, and the frame body is adhered to the thin film sheet; And a thin film sheet cutting step of cutting the thin film sheet adhered to the outer periphery of the frame.
According to this invention, the thin film sheet is stretched in a flat shape by pulling along the two axial directions at least intersecting the outer edge of the thin film sheet by the pulling step. Next, in the plane forming member pressing step, the center portion of the thin film sheet is planarized following the plane portion of the plane forming member. Next, in the frame pressing step, the frame is pressed against the flattened thin film sheet, and the frame follows the flat portion of the plane forming member via the thin film sheet. In this state, the thin film sheet is bonded to the frame body by the bonding process. And by performing a thin film sheet cutting process, the thin film of the state which followed the flatness of the plane formation member is left in a frame, and it can be set as the state affixed on the opening part of the frame.

Moreover, it is preferable that the thin film sticking method of this invention pulls the said thin film sheet in the direction along the extending | stretching direction at the time of manufacture of the said thin film sheet at the said tension | pulling process.
In this case, since the film is pulled in the direction along the stretching direction at the time of manufacturing the thin film sheet, the thin film sheet is uniformly stretched, and the generation of wrinkles and sagging can be suppressed.

Further, in the method for attaching a thin film of the present invention, in the pulling step, the outer edge portion of the thin film sheet is held within a range equal to or larger than the outer shape of the planar portion of the planar forming member used in the planar forming member pressing step. Is preferred.
In this case, since the outer edge portion of the thin film sheet is held in a range equal to or larger than the outer shape of the flat portion of the flat surface forming member, the thin film sheet can be uniformly pulled within the range including the outer shape of the flat portion. Therefore, in the plane forming member pressing step, the flatness of the thin film sheet in the region where the plane forming member is pressed can be improved.

Further, in the thin film attaching method of the present invention, the flat surface forming member used in the flat surface forming member pressing step includes a groove portion penetrating a side portion of the flat surface portion, or a thickness of the flat surface forming member. It is preferable to provide a hole penetrating in the vertical direction.
In this case, when the thin film sheet is pressed by the groove portion that is provided in the flat portion of the flat surface forming member and that penetrates the side portion of the flat surface portion or the hole portion that penetrates in the thickness direction of the flat surface forming member, The air caught between the two can be easily escaped. Therefore, it becomes difficult for air bubbles to enter between the thin film sheet and the flat portion.

In the thin film attaching method of the present invention, the flat surface forming member pressing step uses the flat surface forming member having a side where an outline of the flat portion can be orthogonal to a pulling direction in the pulling step. It is preferable to press the outer shape line of the portion while making it perpendicular to the pulling direction.
In this case, since the component force in the direction intersecting the pulling direction does not act on the thin film sheet from the outline of the flat portion of the plane forming member, the thin film sheet is in a direction different from the pulling direction in the outline of the flat portion. It is possible to suppress movement and deformation.

The pellicle optical element of the present invention is manufactured by applying a thin film to the opening of the frame body using the thin film bonding method of the present invention, and then coating the thin film.
According to the present invention, since the pellicle optical element is manufactured by the thin film attaching method of the present invention, the same effect as the thin film attaching method of the present invention is provided.

  According to the thin film attaching method of the present invention and the pellicle optical element manufactured thereby, the thin film sheet and the thin film sheet are bonded to the frame body in a state in which the frame body is aligned with the flat portion of the flat surface forming member. Since a thin film sheet is cut | disconnected by the outer peripheral part of a frame, and a thin film is affixed on a frame, there exists an effect that the surface accuracy defect of the thin film after affixing can be reduced.

1A is a schematic plan view showing a schematic configuration of a pellicle optical element according to an embodiment of the present invention, FIG. It is the typical perspective view which shows schematic structure of the thin film sticking apparatus for enforcing the thin film sticking method which concerns on embodiment of this invention, and the fragmentary sectional view which follows the CC line. It is a typical perspective view which shows an example of the plane formation member used for the bonding method of the thin film which concerns on embodiment of this invention. It is operation | movement explanatory drawing of the tension | pulling process of the thin film sticking method which concerns on embodiment of this invention. It is a typical perspective explanatory view showing an example of the relation between the pulling direction and the film stretching direction in the pulling step. It is operation | movement explanatory drawing of the plane formation member pressing process of the thin film sticking method which concerns on embodiment of this invention, and the elements on larger scale of the D section. It is operation | movement explanatory drawing of the frame body pressing process and adhesion process of the thin film sticking method which concerns on embodiment of this invention. It is a typical perspective view which shows an example of the plane formation member used for the 1st modification of the bonding method of the thin film which concerns on embodiment of this invention, and another example. It is a typical perspective view which shows an example of the frame used for the 2nd modification of the bonding method of the thin film which concerns on embodiment of this invention. It is typical arrangement explanatory drawing of planar view explaining the 3rd modification of the adhesion method of the thin film concerning the embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
First, a pellicle optical element according to an embodiment of the present invention will be described.
FIG. 1A is a schematic plan view showing a schematic configuration of a pellicle optical element according to an embodiment of the present invention. FIG.1 (b) is AA sectional drawing in Fig.1 (a). FIG.1 (c) is a reverse view of the B view in FIG.1 (b).

As shown in FIGS. 1A, 1B, and 1C, the pellicle optical element 1 of this embodiment includes a frame member 2 (frame body) and a resin film 3 (thin film).
The frame member 2 is a frame for holding the resin film 3 with good flatness. In the present embodiment, a film bonding surface 2a and a back surface portion 2c that are parallel to each other are provided on the front and back in the plate thickness direction, and an opening is formed in each central portion through the rectangular inner peripheral surface 2b in plan view. It consists of a rectangular frame member. The outer dimension of the frame member 2 is L ₁ × L ₂ (where L ₁ ≧ L ₂ ).
Here, the membrane bonding surface 2a is a plane to which the resin film 3 is bonded. The flatness of the film bonding surface 2a means the full width of the cone from the ideal plane of the film bonding surface 2a, and the required flatness depends on the optical characteristics required for the pellicle optical element 1. .

  Further, the back surface portion 2 c is used for biasing the pressing force when the membrane bonding surface 2 a is pressed against the resin film 3. The flatness of the back surface portion 2c is not particularly limited as long as a pressing force that makes the thickness of the adhesive layer substantially uniform can be applied to the film bonding surface 2a along the inner peripheral surface 2b of the frame. For example, it may be a smooth plane parallel to the film bonding surface 2a and having the same flatness, or a rough surface.

Moreover, in this embodiment, the width | variety of the film | membrane adhesion surface 2a and the back surface part 2c which goes to an outer peripheral side from the frame internal peripheral surface 2b is formed in the back surface part 2c so that it is wide, as shown in FIG.1 (b). In addition, the cross section is L-shaped.
As a result, when the resin film 3 is attached to the film bonding surface 2a, a gap is formed on the outer peripheral side of the film bonding surface 2a and on the rear surface side of the back surface portion 2c. Therefore, the adhesive 26 is applied from the outer peripheral side of the film bonding surface 2a. It is easy to supply.

As the material of the frame member 2, an appropriate material can be adopted as long as the material has rigidity capable of maintaining good flatness of the film bonding surface 2 a under use conditions. For example, a metal or a synthetic resin can be used.
In this embodiment, an aluminum alloy is employed. Moreover, the black alumite process is given to the surface for reflection prevention.

The resin film 3 is obtained by coating a resin base material cut to approximately the same size as the outer shape of the frame member 2 according to the optical characteristics of the pellicle optical element 1. And the resin film 3 is adhere | attached on the frame member 2 in the state pressed by the film | membrane adhesion surface 2a.
As the material and the thickness of the base material of the resin film 3, an appropriate material and thickness can be adopted according to the optical characteristics required for the pellicle optical element 1.
For example, a polyethylene terephthalate (PET) resin, a polycarbonate (PC) resin, etc. are employable. Moreover, as thickness, it is preferable that it is 10 micrometers-30 micrometers, for example. Such a base material can be easily obtained because, for example, one produced from a resin material by a biaxial stretching method is commercially available.
For example, when used as a beam splitter, the substrate thickness is more preferably 20 μm or less. The thickness after the coating treatment is preferably 25 μm or less.
For example, in the case of a beam splitter, AR coating (antireflection coating) processing and HM coating (hard multi-coating) processing can be employed as the type of coating processing.

Next, the manufacturing method of the pellicle optical element 1 will be described focusing on the thin film attaching method of the present embodiment in which the resin base material of the resin film 3 is attached to the frame member 2.
Fig.2 (a) is a typical perspective view which shows schematic structure of the thin film sticking apparatus for enforcing the thin film sticking method concerning embodiment of this invention. FIG.2 (b) is a fragmentary sectional view which follows the CC line in Fig.2 (a). FIG. 3 is a schematic perspective view showing an example of a plane forming member used in the thin film attaching method according to the embodiment of the present invention. FIGS. 4A and 4B are operation explanatory views of a pulling process of the thin film bonding method according to the embodiment of the present invention. FIG. 5 is a schematic perspective explanatory view showing an example of the relationship between the pulling direction and the film stretching direction in the pulling step. Fig.6 (a) is operation | movement explanatory drawing of the plane formation member pressing process of the bonding method of the thin film which concerns on embodiment of this invention. FIG. 6B is a partially enlarged view of a portion D in FIG. FIG. 7 is an operation explanatory view of a frame pressing process and an adhesion process of the thin film bonding method according to the embodiment of the present invention.

The thin film sticking method of this embodiment performs a pulling step, a flat surface forming member pressing step, a frame pressing step, an adhesion step, and a thin film sheet cutting step in this order.
Thereby, the resin substrate sheet 4 (see FIG. 4), which is a thin film sheet obtained by cutting the resin substrate of the resin film 3 into a rectangular shape sufficiently larger than the frame member 2, is bonded to the film bonding surface 2a of the frame member 2, Then, it is the method of affixing the resin base material of the resin film 3 on the frame member 2 by cut | disconnecting according to the outer periphery of the frame member 2. FIG.
The pulling process, the flat surface forming member pressing process, the frame body pressing process, and the bonding process of the present embodiment can be performed using a thin film bonding apparatus 100 described below.

As shown in FIGS. 2 and 3, the schematic configuration of the thin-film pasting apparatus 100 is such that four columns 11 are erected on the base 10, and a gantry having a hole 12 a in the center at the upper ends of these columns 11. 12 is installed in the horizontal direction. Further, on the base 10, there is provided an elevating stage 15 that is inserted into the hole 12a of the gantry 12 and can change the height of the tip. As the elevating stage 15, an appropriate linear motion stage whose height can be adjusted by driving a motor can be adopted.
A substantially rectangular flat plate 16 (plane forming member) is placed on the stage upper surface 15a at the tip of the elevating stage 15 so as not to move in the horizontal direction.
On the gantry 12, four sheet pulling mechanisms 13 are installed in directions facing the four side surfaces of the flat plate 16.
In the present embodiment, sheet pulling mechanisms 13A and 13C are installed at positions facing the long side of the flat plate 16, and the sheet pulling mechanism 13B is positioned at a position facing the short side of the flat plate 16 that is in a direction perpendicular thereto. , 13D is installed.

As shown in FIGS. 2A and 3, the flat plate 16 is a plate member whose outer shape is larger than the outer shape of the film bonding surface 2 a of the frame member 2, and on the upper surface when placed on the stage upper surface 15 a. Is formed with a high-precision flat surface portion 16a (planar portion) having a flatness better than the surface accuracy of the pellicle surface required for the pellicle optical element 1. Here, the flatness means the full width of the cone from the ideal plane of the high-precision flat portion 16a.
In the present embodiment, the flat plate 16 is a rectangular flat plate having an outer dimension of W ₁ × W ₂ (W ₁ ≧ W ₂ , W ₁ > L ₁ , W ₂ > L ₂ ), An example in which the entire upper surface of the flat plate 16 is a high-precision flat portion 16a will be described.
A chamfered portion 16b is formed at the corners of the four corners on the outer edge portion of the high-precision flat portion 16a, and a chamfered portion 16c is also formed on a ridge line portion surrounding the high-precision flat portion 16a including the chamfered portion 16b. Thereby, the sharp convex shape and edge shape are removed from the outer edge part of the high precision plane part 16a. As a result, even if the resin base sheet 4 is pressed against the high-precision flat portion 16a and pulled, the resin base sheet 4 is not damaged.
In addition, it is preferable that the ridge line part formed by these chamfered parts 16b and 16c is polished or thread chamfered. Further, the chamfered portions 16b and 16c may be replaced with rounded portions with rounded corners.

  As the material of the flat plate 16, for example, glass, synthetic resin, metal or the like can be used. Among them, glass is a particularly preferable material because it is relatively easy to process the high-precision flat portion 16a and is excellent in environmental stability and flatness stability over time.

In the present embodiment, each sheet pulling mechanism 13 will be described using an example in which the types and dimensions of the constituent members are common.
As shown in FIGS. 2A and 2B, the schematic structure of the sheet pulling mechanism 13 includes a uniaxial stage 20, a stage driving unit 21, a clamp unit 23, a pulling plate 22, and a pressing magnet 14.

The uniaxial stage 20 fixes the pulling plate 22 to the upper surface and holds it so as to be movable in a uniaxial direction along a horizontal plane.
The stage driving unit 21 is a driving unit that drives the single-axis stage 20 manually or automatically in the single-axis direction. For example, a screw drive mechanism or a linear motor can be employed.
The clamp part 23 is for fixing the movement position of the uniaxial stage 20 as needed.
Although not particularly illustrated, each sheet pulling mechanism 13 is provided with a force sensor that detects a pulling force on the resin base sheet 4. However, the force sensor may be omitted when the allowable range of the residual stress after application of the resin base sheet 4 is large.

The tension plate 22 is a flat plate member that can be attracted by the pressing magnet 14 in order to hold the outer edge portion of the resin base sheet 4, and has a width in a direction perpendicular to the moving direction of the uniaxial stage 20 on a horizontal plane. Is formed in a width U larger than W ₁ which is the longitudinal width of the flat plate 16. It is fixed to the upper surface of the uniaxial stage 20 and can move integrally with the uniaxial stage 20.
On the pressing surface 22a which is the upper surface of the pulling plate 22, a locking projection 22b having a certain height is formed on the edge facing the flat plate 16 along the direction perpendicular to the moving direction of the uniaxial stage 20. Yes. The cross section perpendicular to the extending direction of the locking projection 22b is, for example, a semicircular shape, and the resin base sheet 4 pressed from the upper surface side is brought into linear contact with the resin base sheet 4 It can be slidably locked.
As the material of the pull plate 22, an appropriate magnetic material can be adopted. For example, SUS400 type magnetic stainless steel can be suitably employed.

As shown in FIG. 2A, the pressing magnet 14 is a rectangular flat magnet whose outer shape in plan view is W × V (where U>W> W ₁ ). The size of the width V can be set to an appropriate size necessary for holding the resin base sheet 4 in consideration of the adsorption force and the like.

Next, each process of the thin film bonding method of this embodiment will be described.
A tension | pulling process is a process of hold | maintaining the outer edge part of the resin base material sheet 4, and stretch | stretching the resin base material sheet 4 to planar shape by pulling along at least biaxial direction.
First, as shown in FIG. 4A, the elevation stage 15 is driven, and the position in the height direction of the high-precision flat portion 16a fixed on the stage upper surface 15a is set to the locking projection of each sheet pulling mechanism 13. It is set at a position lower than the top of 22b.
In each sheet pulling mechanism 13, the uniaxial stage 20 is driven by the stage driving unit 21, and each pulling plate 22 is moved to the reference position on the flat plate 16 side.
And the resin base material sheet 4 is covered so that the outer edge part of the resin base material sheet 4 may cover on each tension | pulling plate 22. FIG.
At this time, the resin base material sheet 4 is arranged so that the stretching direction at the time of manufacture matches the facing direction of the sheet pulling mechanism 13. For example, the stretching direction indicated by the arrow P in FIG. 5 is aligned with the direction in which the sheet pulling mechanisms 13B and 13D face each other, and the stretching direction similarly indicated by the arrow Q is aligned with the direction in which the sheet pulling mechanisms 13A and 13C face each other. .
Then, the pressing magnet 14 is arranged on the resin base sheet 4 on the pressing surface 22 a and is attracted to the tension plate 22, and the outer edge portion of the resin base sheet 4 is sandwiched between the tension plate 22 and the pressing magnet 14. Then, the outer edge portion of the resin base sheet 4 is held.
At this time, the pressing magnet 14 is arranged so that the side of the width W faces the flat plate 16 and the side portion of the opposing flat plate 16 enters the width W. In addition, on the sheet pulling mechanisms 13 facing each other, it is preferable that the arrangement positions of the pressing magnets 14 in the width W direction are substantially aligned with each other.

Next, as shown in FIG. 4B, the uniaxial stage 20 is driven by the stage driving unit 21 of each sheet pulling mechanism 13 to move the pulling plate 22 in the direction away from the flat plate 16, thereby Pull the material sheet 4. Then, the movement is stopped at a position where a preset tensile force is applied to the resin base sheet 4 by a force sensor (not shown). Since this position does not change until the end of the bonding process, the position of each uniaxial stage 20 may be fixed by each clamp portion 23.
The pulling force at this time is a residual stress that does not affect the optical characteristics of the pellicle optical element 1 including the tension applied by the subsequent flat surface forming member pressing step when the tension of the resin base sheet 4 is applied. Thus, it sets in consideration of the tensile elastic modulus of the resin base material sheet 4 in the tensile direction. In addition, it is preferable that the tension generated in the central portion of the resin base sheet 4 has as little anisotropy as possible.
In this way, the resin base sheet 4 is pulled in the outer peripheral direction along the directions of the arrows P and Q, which are the extending directions at the time of manufacture. Then, the flat plate 16 is stretched between the four pressing surfaces 22 a above the flat plate 16.

In the present embodiment, the outer edge of the outer peripheral side is fixed by the pressing magnet 14 in a state where the resin base sheet 4 is locked to the locking protrusion 22b. Therefore, for example, even if the placement position of the pressing magnet 14 varies, a horizontal pulling force acts on the central portion of the resin base sheet 4 through each locking projection 22b, and the central portion of the resin base sheet 4 is It is stretched in a precise rectangular shape.
In addition, since the resin base sheet 4 is held over the width W by the pressing magnet 14, a tensile force that is a substantially equally distributed load can be applied between the widths W. For this reason, it is possible to prevent the resin base sheet 4 from undulating.

Next, a flat surface forming member pressing step is performed.
In this step, the resin base sheet 4 is pressed against the central portion of the resin base sheet 4 stretched by the pulling step on the high precision flat portion 16a side, so that the resin base sheet 4 is placed on the high precision flat portion of the flat plate 16. This is the step of making it 16a.
That is, as shown in FIGS. 6A and 6B, the elevating stage 15 is raised in a state where the resin base sheet 4 is stretched, and the high-precision flat portion 16a is placed on the top of the locking projection 22b of the pressing surface 22a. Move to a higher position by h (where h> 0).
At this time, it is preferable to raise the elevating stage 15 at a low speed so as not to leave bubbles between the high-precision flat portion 16 a and the resin base sheet 4. Since the resin base sheet 4 is slightly slackened at the center due to the action of gravity, the resin base sheet 4 comes in contact with the center of the high-precision flat portion 16a and gradually contacts the outer peripheral side. If the movement speed of the resin is high, the air pressure between the resin base sheet 4 and the high precision flat portion 16a increases and the resin base sheet 4 swells slightly upward, so that the high precision flat portion 16a contacts from the outer peripheral side. However, bubbles are easily left behind in the center.

  If the height h is a height at which the resin base sheet 4 is aligned with the high-precision flat portion 16a and a pressing force can be obtained so that the resin base sheet 4 can be closely contacted with no gap, the tension generated in the resin base sheet 4 is the pellicle optical element. As long as the optical characteristic of 1 is not affected, it can be set appropriately.

  According to this step, the resin base sheet 4 stretched flat in the pulling step can be stretched on the high-precision flat portion 16a to a flatness substantially equal to the flatness of the high-precision flat portion 16a.

Next, a frame pressing process is performed.
This step is a step of pressing the frame member 2 in a state where the film bonding surface 2a is opposed to the portion of the resin base sheet 4 pressed on the high precision flat portion 16a by the flat surface forming member pressing step. is there.
First, as shown to Fig.7 (a), the frame member 2 is arrange | positioned so that the film | membrane adhesion surface 2a may contact | abut to the resin base material sheet 4 on the high precision plane part 16a.
In the case of the present embodiment, since the high-precision flat portion 16 a is formed on the entire upper surface of the flat plate 16, the frame member 2 may be disposed anywhere on the flat plate 16.
However, in the case where the high-precision flat portion 16a is formed on a part of the upper surface of the flat plate 16 and the arrangement of the high-precision flat portion 16a is rough, the portion where the high-precision flat portion 16a is densely arranged. The film adhesion surface 2a is disposed on the surface.

Then, as shown in FIG. 7B, the weight member 24 is placed on the back surface portion 2c of the frame member 2, and an even downward load is applied on the back surface portion 2c.
The weight member 24 is a member made of a metal block having a mass with which an appropriate pressing force can be obtained. In the present embodiment, a rectangular parallelepiped block having a pressing surface 24 a having a larger area than the outer shape of the back surface portion 2 c of the frame member 2 is used.
Thereby, the film | membrane adhesion surface 2a is pressed on the resin base material sheet 4 pressed on the high precision plane part 16a. At this time, even if the frame member 2 is distorted, it is corrected by the pressing force of the weight member 24.
That is, according to this process, the resin base material sheet 4 and the film bonding surface 2a are pressed by the weight member 24 in a state following the high-precision flat portion 16a.

Next, an adhesion process is performed.
This step is a step in which an adhesive is applied from the outer peripheral portion of the frame member 2 that is pressed against the resin base sheet 4 in the frame pressing step to adhere the frame member 2 to the resin base sheet 4.
In this step, the abutting portion between the film adhesion surface 2a and the resin base sheet 4 using the adhesive application mechanism 25 having a discharge nozzle or the like at the tip in a state where the weight member 24 is placed on the frame member 2. The adhesive 26 is applied to the entire periphery of the frame member 2 from the outer peripheral side of the frame member 2 in the vicinity of And the resin base material sheet 4 and the frame member 2 are adhere | attached because the adhesive agent 26 solidifies.
When the bonding is completed, the weight member 24 is removed, the pulling force by the sheet pulling mechanism 13 is released, and each pressing magnet 14 is removed.
The type of the adhesive 26 is not particularly limited as long as it can be satisfactorily bonded to the film bonding surface 2a and the resin base sheet 4. In the present embodiment, an epoxy resin adhesive is employed.

Next, a thin film sheet cutting process is performed.
This step is a step of cutting the resin base sheet 4 bonded to the frame member 2 by the bonding step at the outer peripheral portion of the frame member 2.
That is, the frame member 2 and the resin base material sheet 4 are removed from the thin film pasting device 100, and the resin base material sheet 4 is cut by an appropriate cutting device.

  As described above, when the thin film sheet cutting step is completed, a coating process such as AR coating or HM coating is performed on the base material bonded to the film bonding surface 2a using a thin film deposition apparatus or the like. Thereby, the pellicle optical element 1 is completed.

In the pellicle optical element 1 manufactured by using the thin film attaching method of the present embodiment, the resin base sheet 4 and the frame member 2 are aligned with the high-precision flat portion 16a of the flat plate 16, Since the resin base sheet 4 is bonded to the frame member 2, the pellicle optical element 1 having a surface accuracy substantially equal to the flatness of the high-precision flat portion 16a can be easily manufactured.
Moreover, since the film | membrane adhesion surface 2a is pressed against the resin base material sheet 4 and an adhesion | attachment process is performed, compared with the case where a frame is pressed against the resin base material stretched in space, the film | membrane adhesion surface 2a and resin Variations in contact force and contact state with the base material sheet 4 are remarkably reduced, and the frame member 2 can be prevented from being distorted and the resin base material sheet 4 from being waved. Moreover, the adhesion failure by the adhesive agent 26 leaking into the frame of the frame member 2 from a large gap can be reduced.
Therefore, it is possible to reduce surface accuracy defects of the resin film 3 of the pellicle optical element 1.

Next, a first modification of the thin film attaching method of the present embodiment will be described.
FIGS. 8A and 8B are schematic perspective views showing an example and other examples of the plane forming member used in the first modification of the thin film attaching method according to the embodiment of the present invention.

  This modification is different from the flat plate 16 in the thin film bonding apparatus 100 according to the above embodiment, in that the flat plate 16A (plane forming member) shown in FIG. 8A or the flat plate 16B shown in FIG. 8B. (Plane forming member) is used. Hereinafter, a description will be given focusing on differences from the above embodiment.

The flat plate 16A is provided with a plurality of grooves 16d penetrating to the side of the flat plate 16A on the upper surface where the high-precision flat portion 16a is formed. If the groove part 16d is a groove | channel which can distribute | circulate air to a side part, cross-sectional shape will not be specifically limited.
By using such a flat plate 16A in place of the flat plate 16, air sandwiched between the resin base sheet 4 and the high-precision flat portion 16a escapes to the groove portion 16d in the flat surface forming member pressing step. And discharged to the side of the flat plate 16A. Therefore, it is difficult for air bubbles to be sandwiched between the high-precision flat portion 16a and the resin base sheet 4 in the flat surface forming member pressing step. Thereby, since the raising / lowering stage 15 can be moved rapidly, manufacturing efficiency can be improved.
Moreover, since air tends to flow in from the groove part 16d also when removing the resin base material sheet 4 from on the high precision plane part 16a after an adhesion | attachment process, it can remove easily.

The flat plate 16B is provided with a plurality of holes 16e penetrating in the thickness direction of the flat plate 16A in a square lattice shape on the upper surface where the high-precision flat portion 16a is formed. If the hole 16e is a hole through which air can flow on the back surface side, the cross-sectional shape and the through path are not particularly limited.
By using such a flat plate 16B instead of the flat plate 16, air sandwiched between the resin base sheet 4 and the high-precision flat portion 16a escapes to the hole 16e in the flat surface forming member pressing step. Is released to the back side of the flat plate 16B. Therefore, similarly to the flat plate 16 </ b> A, air bubbles are less likely to be sandwiched between the high-precision flat portion 16 a and the resin base sheet 4 in the flat surface forming member pressing step. Thereby, since the raising / lowering stage 15 can be moved rapidly, manufacturing efficiency can be improved. Moreover, it becomes easy to remove the resin base material sheet 4 after an adhesion | attachment process.
Since the flat plate 16B has a continuous high-precision flat portion 16a formed between the holes 16e, the film bonding surface 2a can be placed on the continuous high-precision flat portion 16a. it can.

Next, a second modification of the thin film attaching method of this embodiment will be described.
FIG. 9 is a schematic perspective view showing an example of a frame used in the second modification of the thin film attaching method according to the embodiment of the present invention.

  In this modification, a frame member 200 (frame body) is used instead of the frame member 2 of the above embodiment. Hereinafter, a description will be given focusing on differences from the above embodiment.

  As shown in FIG. 9, the frame member 200 is formed of an annular member having an outer diameter smaller than the outer shape of the flat plate 16, and is replaced with a rectangular frame inner peripheral surface 2 b of the frame member 2. A peripheral surface 200b is provided. The film bonding surface 2a and the back surface portion 2c are the same as the frame member 2 except that the shapes in plan view are annular, and the material of the frame member 200 is the same as that of the frame member 2.

The frame member 200 is disposed at an appropriate position on the resin base sheet 4 pressed against the high-precision flat surface portion 16a in the frame body pressing step so as to cover the high-precision flat surface portion 16a. Since it can be pressed against the material sheet 4, a pellicle optical element having a circular pellicle surface can be manufactured in exactly the same manner as in the above embodiment.
Thus, the shape of the frame member 2 is not limited to the rectangular frame as in the above-described embodiment, and an appropriate shape that can be disposed on the flat plate 16 can be employed. In addition to the circular ring, the present invention can be carried out by deforming into a shape such as an elliptical frame, a triangular frame, or a polygonal frame.

Next, a third modification of the thin film attaching method of the present embodiment will be described.
FIG. 10 is a schematic layout explanatory diagram in plan view for explaining a third modification of the thin film attaching method according to the embodiment of the present invention.

As shown in FIG. 10, in this modification, when the arrows p and q, which are stretching directions at the time of manufacturing the resin base sheet 40, intersect at an angle different from 90 degrees, the respective stretching directions are This is an example of the case where the frame member 2 is attached to the frame member 2 so that the diagonal direction of the frame member 2 is close to the diagonal direction.
In this case, in the same manner as in the above-described embodiment, when the outline of the plane plate 16 is orthogonal to F _p and F _q which are the pulling directions along the arrows p and q, the width of the plane plate 16 is the diagonal line of the frame member 2. It is necessary to make the length or longer, and the area of the high-precision flat portion 16a of the flat plate 16 is larger than that in the above embodiment. Such a flat plate 16 takes time and labor to process the high-precision flat portion 16a, and increases the manufacturing cost.
Therefore, in this modification, the outer shape of the frame member 2 and the outer shape of the plane plate 16 are arranged in parallel so that the plane plate 16 has a size close to that of the frame member 2, and the pulling direction F _p , against F _q, it is arranged so outline of the flat plate 16 intersect at an angle.
For this reason, four tension plates 220 are used in place of the four tension plates 22 of the thin film bonding apparatus 100. Hereinafter, a description will be given focusing on differences from the above embodiment.

The tension plate 220 is an L-shaped flat plate in plan view, and is arranged so that the corners inside the L-shape are along the outer periphery of the corners of the plane plate 16, and each tension plate 22 is the most flat plate 16. When approaching (arrangement of FIG. 10), a rectangular hole having an inner peripheral portion parallel to the outer peripheral portion of the flat plate 16 is formed.
Locking projections 220b that protrude upward are formed along the inner circumference of the L shape on the upper surface (the front side of the drawing in FIG. 10) of each pulling plate 220 on the side facing the flat plate 16. That is, each locking protrusion 220b is disposed in parallel with the rectangular outline of the opposing flat plate 16.
Although not particularly illustrated, the pressing magnet 14 can employ a magnet having an appropriate shape as long as the resin base sheet 40 can be held on the pulling plate 220 in the vicinity of the locking protrusion 220b. For example, an L-shaped magnet member may be used, or a plurality of rectangular plate magnets may be used.
Although not particularly illustrated, a uniaxial stage 20, a stage driving unit 21, a clamp unit 23, and the like similar to those of the above-described embodiment are arranged below the pulling plates 220 so that the pulling directions _Fp and _Fq are in the moving direction. Is installed.

According to the present modification, when the tension plate 220 is moved in the tension directions F _p and F _q in the tension process, the locking protrusions 220 b of the tension plates 220 are moved in parallel with the outline of the flat plate 16. Thereby, the resin base material sheet 40 is stretched in a planar shape in a rectangular region surrounded by the locking protrusions 220b along the extending direction at the time of manufacture. Therefore, the resin base sheet 40 can be attached to the frame member 2 in the same manner as in the above embodiment.

  In the above description, the example in which the stretching direction at the time of manufacturing the thin film sheet is matched with the pulling direction in the pulling process has been described, but the waviness of the thin film sheet, the residual stress in the thin film sheet, and the like are acceptable. If so, it may be pulled in a direction deviating from the stretching direction during production.

In the above description, an example in which the outer edge portion of the thin film sheet is held in a range equal to or larger than the outer shape of the planar forming member in the pulling process has been described. However, the undulation of the thin film sheet, residual stress in the thin film sheet, etc. If it is a range, you may hold | maintain in the range narrower than the external shape of a plane formation member.
For example, you may hold | maintain with a some holding | maintenance part along the outline of a plane formation member. In this case, since the stress distribution is relaxed from the holding portion toward the plane forming member, by appropriately setting the interval between the plurality of holding portions and the distance to the plane forming member, It becomes possible to equalize the tensile stress distribution.

  In the above description, the film bonding surface 2a of the frame member 2 has been described as an example. However, the film bonding surface 2a is located on the resin base sheet 4 along the circumferential direction of the frame member 2. It is only necessary to form a flat portion that can be adhered, and an inclined surface portion that extends from the flat portion toward the outer peripheral portion of the frame member 2 and moves away from the resin base sheet 4 toward the outer peripheral portion. You may have. In this case, the wedge-shaped space between the resin base sheet 4 and the inclined surface portion makes it easier for the adhesive to enter in the bonding step, and the manufacturing efficiency can be improved.

In the description of the first modified example, the example in which the regularly disposed grooves 16d and the holes 16e are formed on the surface of the plane forming member has been described. However, these arrangements are regular. It does not have to be. For example, the density of the distribution of the high-precision flat portion 16a may be changed by changing these arrangement positions.
Moreover, you may change the shape and magnitude | size of a groove part or a hole part according to a place. Moreover, it is good also as a plane formation member provided with both a groove part and a hole.

In the above description, the outer edge portion of the thin film sheet has been described as being held between the pulling plate 22 and the pressing magnet 14 that are attracted by magnetic force. However, the pressing plate that replaces the pressing magnet 14 is pulled. The plate 22 may be clamped by being screwed or urged by a pressure spring or the like.
Further, air adsorption may be adopted as long as a holding force that resists the pulling force that pulls the resin base sheet 4 is obtained. For example, an air suction hole is provided in the pressing surface 22a of the pulling plate 22, and after the resin base sheet 4 is placed on the pressing surface 22a, air is sucked and the resin base sheet 4 can be adsorbed by air. .

  Further, in the above description, an example in which each sheet pulling mechanism 13 has the same configuration has been described. However, for example, in order to change the magnitude of the pulling force in each facing direction and the holding force with respect to the resin base sheet 4, the sheet pulling mechanism is changed. It is good also as a structure which changed the shape, dimension, etc. of the structural member for every mechanism 13. FIG.

  Further, all the constituent elements described in the above embodiments can be appropriately combined and implemented within the scope of the technical idea of the present invention, if technically possible.

1 Pellicle optical element 2, 200 Frame member (frame body)
2a Membrane bonding surface 3 Resin film (thin film)
4, 40 Resin base sheet (thin film sheet)
13 Film pulling mechanism 14 Holding magnets 16, 16A, 16B Planar plate (plane forming member)
16a High-precision plane part (plane part)
16d Groove part 16e Hole part 22, 220 Pulling plate 22a Holding surface 22b, 220b Locking protrusion 24 Weight member 25 Adhesive application mechanism 100 Thin film sticking apparatus

Claims (6)

A thin film attaching method for attaching a thin film to an opening of a frame,
The thin film sheet formed in a sheet shape larger than the opening of the frame is held at the outer edge of the thin film sheet, and is stretched along at least two intersecting axial directions to stretch the thin film sheet in a planar shape. A pulling process;
By pressing a flat surface forming member having a flat portion sized to cover the frame on the flat portion side to the central portion of the thin film sheet stretched by the pulling step, the thin film sheet is applied to the flat portion. A flat surface forming member pressing process,
A frame body pressing step of pressing the frame body in a state where the opening is opposed to the thin film sheet portion pressed against the flat surface portion by the flat surface forming member pressing step;
An adhesion step of applying an adhesive from the outer periphery of the frame body in a state of being pressed against the thin film sheet by the frame body pressing step, and bonding the frame body to the thin film sheet;
A thin film sheet cutting method comprising: a thin film sheet cutting step of cutting the thin film sheet bonded to the frame body at an outer peripheral portion of the frame body by the bonding step. In the pulling process,
The method of attaching a thin film according to claim 1, wherein the thin film sheet is pulled in a direction along a stretching direction at the time of manufacturing the thin film sheet. In the pulling process,
3. The thin film attaching method according to claim 1, wherein an outer edge portion of the thin film sheet is held in a range equal to or larger than an outer shape of the planar portion of the planar forming member used in the planar forming member pressing step. . The plane forming member used in the plane forming member pressing step is
The groove portion penetrating the side portion of the flat portion or the hole portion penetrating in the thickness direction of the flat surface forming member is provided in the flat portion. A method for attaching thin films. In the plane forming member pressing step,
A flat surface forming member having a side that can be orthogonal to the pulling direction in the pulling step is used for pressing the flat line with the outline of the flat part being orthogonal to the pulling direction. The thin film sticking method according to any one of claims 1 to 4. After pasting a thin film on the opening of the frame using the thin film pasting method according to claim 1,
A pellicle optical element manufactured by coating the thin film.

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