JP7375210B2 - Dustproof structure for alignment unit - Google Patents

Description

The present invention relates to a dustproof structure for an alignment unit.

In the world of photolithography, in addition to exposure techniques for small areas such as semiconductor IC chips, batch exposure techniques have been developed for larger areas such as flat panel displays such as liquid crystal displays.

For batch exposure of such a large area, mirror projection optical type exposure apparatuses and the like are on the market.
The basic configuration of a mirror projection optical type exposure apparatus consists of a large concave mirror, a small convex mirror, and a trapezoidal mirror that are manufactured with the utmost precision. A photomask attached to the top of the unit is irradiated with ultraviolet rays, and after reflection a plurality of times (for example, five times), the circuit pattern on the photomask is transferred and exposed onto a glass substrate.

In recent years, in the flat panel industry, patterns for smartphones, tablet devices, etc. have become increasingly high-definition. As one method for realizing high definition, it is desired to perform scanning exposure by aligning the focal position of the exposure light within the exposure apparatus with the surface position of the exposure substrate. In this case, the development of faster and more accurate alignment techniques is also required. However, when a glass substrate undergoes heat treatment, the absolute dimensions of the substrate itself may change, and various distortions occur in the pattern coordinates formed in the previous process. To understand this, it is necessary to measure the positions of many reference points.

Conventionally, a method (AS method: Alignment Scope method) was adopted in which the overlapping state of the alignment mark on the photomask and substrate was measured through the optical path of the actual mirror optical system, but in recent years, the overlapping state of the alignment mark on the photomask and substrate was measured through the optical path of the actual mirror optical system. A new measurement method (OAS method: Off-axis Scope method) that directly observes a mark nearby and performs positioning indirectly has been introduced (for example, Patent Document 1). A device that performs the above measurements using the AS method and/or OAS method is called, for example, an alignment unit, and is used in combination with an exposure device.

Japanese Patent Application Publication No. 2005-116965

The measurement section (lens section) in the OAS method is located closer to the substrate stage than the measurement section (lens section) in the AS method, so in the OAS method, when the exposure apparatus is driven (i.e., when the substrate stage is It is easily affected by dust generated during driving in the X and Y directions. Excessive influence from such dust causes a problem in that accurate alignment becomes difficult.
Therefore, for example, in the OAS method, it is conceivable to arrange a dustproof cover over the lens portion of the alignment unit. However, a suitable dustproof cover for an OAS type alignment unit has not been proposed. OAS type alignment units have different conditions compared to AS type alignment units, such as space constraints and being affected by wind pressure due to high-speed movement of the substrate stage. The pellicle used (a pellicle having a pellicle film on one side of the frame and a masking adhesive layer on the other side) cannot be used as is.

The present invention has been proposed in view of such conventional circumstances, and an object of the present invention is to provide a dustproof structure suitable as a dustproof cover for an OAS type alignment unit.

[1]
a frame forming an opening;
a dustproof membrane stretched and supported on one side of the frame so as to cover the opening;
A dustproof structure comprising:
A dustproof structure for an alignment unit, comprising at least one of a fixing part for mechanically fixing the dustproof structure to the alignment unit, and a magnet for fixing the dustproof structure to the alignment unit.
[2]
The dustproof structure according to [1], wherein the dustproof film has a transmittance of 80% or more at an incident angle of -10° to 10° for light with a wavelength of 440 to 780 nm.
[3]
The dustproof structure according to [1] or [2], wherein the dustproof film has a flattening amount of -3.0 mm to +3.0 mm.
[4]
One side of the frame body has a part where the dustproof film is arranged and a part where the dustproof film is not arranged,
The dustproof structure according to any one of [1] to [3], wherein the fixing part is provided in a portion of one side of the frame body where the dustproof film is not provided.
[5]
The dustproof structure according to any one of [1] to [4], wherein the frame contains sulfate ions of 0.3 ppm or less.
[6]
The dustproof structure according to any one of [1] to [5], wherein the other side of the frame is a non-adhesive surface on which no adhesive layer is formed.
[7]
The dustproof structure according to any one of [1] to [6], comprising a total of two or more and a total of 16 or less of the fixing parts.
[8]
The dustproof device according to any one of [1] to [7], wherein the frame includes an inner circumferential portion forming the opening, and an outer portion protruding outward from a part of a side surface of the inner circumferential portion. Structure.
[9]
The dust-proof structure according to [8], wherein the outer part has the fixing part defining a screw groove and/or a screw hole for screw-fixing the dust-proof structure to an alignment unit.
[10]
The dust-proof structure according to any one of [1] to [7], wherein the dust-proof structure has a suspension receiving part that includes a step and/or a slope that allows the dust-proof structure to be lifted.
[11]
The dustproof structure according to [10], wherein the suspension receiving part is provided on the side surface of the inner peripheral part where the outer part is formed.
[12]
The dustproof structure according to any one of [1] to [11], wherein the frame has a flatness of more than 0 and 200 μm or less.
[13]
The dustproof structure according to any one of [1] to [12], wherein the dustproof film has a thickness of 1.5 to 8.0 μm.
[14]
[1] to [13], wherein the fixing part includes an area that includes the assumed central axis of the screw and in which a cross-sectional view perpendicular to the dustproof film satisfies any of the following (1) to (3); The dustproof structure described in any of the above.
(1) The width T1 of the part where the dustproof film is stretched and supported on the inner circumference exceeds the thickness H1 of the inner circumference (T1>H1>0)
(2) The thickness H2 of the outer part is less than or equal to 1/2 of the thickness H1 of the inner circumferential part (1/2 H1≧H2>0). The ratio (T2/T3) of the total width T2 of the peripheral part and the outer part is within the range of 1 to 13 [15]
The dustproof structure according to any one of [1] to [14], wherein the frame body and the dustproof film have different natural frequencies.

According to the present invention, it is possible to provide a dustproof structure for an alignment device that is suitable as a dustproof cover for an OAS type alignment device.

1 is a diagram schematically showing a configuration example of a dustproof structure of the present invention. FIG. 2 is a diagram schematically showing an exposure optical system in an exposure apparatus. FIG. 2 is a diagram schematically showing an alignment optical system in an exposure apparatus. It is a figure which shows typically another example of a structure of the dustproof structure of this invention. It is a figure which shows typically another example of a structure of the dustproof structure of this invention. It is a figure which shows typically another example of a structure of the dustproof structure of this invention. It is a figure which shows typically another example of a structure of the dustproof structure of this invention. It is a figure which shows typically another example of a structure of the dustproof structure of this invention.

(Embodiment 1)
Hereinafter, an embodiment for carrying out the present invention (hereinafter referred to as "this embodiment") will be described in detail.
FIG. 1 is a diagram schematically showing a configuration example of a dustproof structure according to the present embodiment, in which (a) is a plan view and (b) is a cross-sectional view.
The dustproof structure 1 of this embodiment is a dustproof structure for an alignment unit, and includes a frame 2 having an opening 2a, and a dustproof membrane stretched and supported on one side of the frame 2 so as to cover the opening 2a. 3, and a fixing part for mechanically fixing the dustproof structure 1 to the alignment unit.

<Exposure device>
The dustproof structure 1 of this embodiment is suitable as a dustproof cover for an OAS type alignment unit.
First, an exposure apparatus equipped with an OAS type alignment unit to which the dustproof structure 1 of this embodiment is applied will be described.

2 and 3 are diagrams schematically showing one configuration example of an exposure apparatus. FIG. 2 mainly shows an exposure optical system, and FIG. 3 mainly shows an alignment optical system.
The exposure apparatus 10 includes a mask 11 on which a pattern 11a is formed, a mask stage 12 on which the mask 11 is mounted and is movable in the A substrate stage 14 that holds the substrate 13 and is movable in the X, Y, and θ directions, an illumination optical system 15, and a mirror projection system are provided. The mask stage 12 and the substrate stage 14 are each moved in the X and Y directions by motors (not shown).

The illumination optical system 15 illuminates the mask 11 at the exposure position with light of a specific wavelength and exposes the photosensitive layer 13a (resist) on the substrate 13 through the pattern 11a on the mask 11. pattern 11a can be transferred onto the substrate 13. The mirror projection system is configured by a combination of a concave mirror 16, a convex mirror 17, and a bending mirror 18 (trapezoidal mirror), and projects the pattern image of the mask 11 aligned at a predetermined position by the mask stage 12 onto the substrate 13 at the same magnification. .

By synchronously scanning and controlling the mask stage 12 and the substrate stage 14, the pattern 11a drawn on the mask 11 is transferred to the photosensitive layer 13a (resist) on the substrate 13. The pattern is transferred to the entire surface of the substrate 13 by repeating this transfer exposure process using synchronous scan control while moving the substrate stage 14 step by step.

In the exposure apparatus 10, the alignment optical system includes an alignment scope (AS) 20 and an off-axis alignment scope (OAS) 21, as shown in FIG.

The AS 20 uses exposure light emitted from the illumination optical system 15 to measure the overlapping state of the alignment marks on the mask 11 and the substrate 13 through the optical path of the exposure optical system.

The OAS 21 includes an illumination section 21a that irradiates the alignment mark on the substrate 13 with illumination light (non-exposure light) having a wavelength different from that of the exposure light, and an imaging section (not shown) that captures an image of the reflected light.

The captured image is subjected to measurement processing by an image processing device (not shown) to obtain the position of the alignment mark. Then, each correction amount (X, Y shift component, rotation component, X, Y magnification component, X and Y perpendicularity component) is calculated from this measurement result.

A control device (not shown) that controls the mask stage 12 and the substrate stage 14 corrects the magnification of the mirror projection system, the position/rotation of the substrate stage 14, and the amount of synchronization deviation between the mask stage 12 and the substrate stage 14 according to the correction amount. At the same time, perform exposure processing.

The dustproof structure 1 of this embodiment is used, for example, in the exposure apparatus 10 as described above, by being attached to the lower part of the OAS 21 (see FIG. 3).
The dustproof structure 1 of this embodiment will be described below.

<Dustproof structure>
The dustproof structure 1 is a dustproof structure for an alignment unit, and includes a frame 2 forming an opening 2a, and a dustproof membrane 3 stretched and supported on one side of the frame 2 so as to cover the opening 2a. , is provided. The dustproof structure 1 of this embodiment includes a fixing part for mechanically fixing the dustproof structure 1 to the alignment unit (OAS 21).

The frame body 2 extends and supports the dustproof film 3, and includes a fixing part for attaching the dustproof structure 1 to the alignment unit.

The frame body 2 can have any shape that allows the dust-proof film 3 to be stretched on the frame body 2. For example, when the frame body 2 is viewed from the front, it may have a rectangular, polygonal, circular, oval shape, etc. can have an external shape of The rectangle is a square, a rectangle, or the like, and can have both a case with right angle corners and a substantially rectangular case with rounded corners. Polygons include triangles, trapezoids, parallelograms, pentagons, hexagons, and the like.

As shown in FIG. 1, the frame 2 has an edge. The edge can have a rod-shaped edge member that extends linearly. A pair of edge members can be spaced apart from each other and arranged parallel to each other, and similarly, another pair of edge members can also be arranged parallel to each other and spaced apart from each other. The two edge members in contact can be connected at their ends at substantially right angles to each other. An opening 2a is defined by the edge members connected in a closed shape.

The frame 2 and its edge members are made of, for example, aluminum; aluminum alloy (for example, 5000 series, 6000 series, 7000 series, etc.); steel; stainless steel; magnesium alloy; ceramics (for example, SiC, AlN, _{Al2O3 ,} etc.); Composite materials of ceramics and metals (for example, Al-SiC, Al-AlN, Al-Al ₂ O _3, etc.); Engineering plastics such as PE, PA, PC, and PEEK; Fiber composite materials such as GFRP and CFRP; or these It can be made of known materials such as combinations of.

In the case of aluminum, an anodic oxide film may be formed by alumite treatment. Generally, alumite includes sulfuric acid alumite using a sulfuric acid bath as a treatment bath for electrolytic treatment, oxalic acid alumite using an oxalic acid bath, etc., but those that do not substantially contain sulfuric acid (sulfuric acid free) It is preferable that
In particular, in the dustproof structure 1 of this embodiment, it is preferable that the sulfate ion contained in the frame 2 is 0.3 ppm or less.

Ions, outgas, etc. may be generated from the photosensitive layer etc. due to the heat of the exposure light. Furthermore, there is a risk that the oxide film on the surface of the frame will decompose. In particular, in the case of sulfuric acid alumite, the generated sulfate ions react with the ions generated above, outgas, etc. (ammonia in the atmosphere, etc.), causing cloudiness on the dust-proof film 3, making it impossible to accurately and quickly measure alignment. there is a possibility. The dustproof structure 1 of this embodiment, in which the sulfate ions contained in the frame 2 is 0.3 ppm or less, can reduce the possibility that such a situation will occur.

Even if it is other than alumite, by using materials with low sulfate ion content or coating the frame with a coating, in other words, using materials with sulfate ions of 0.3 ppm or less, sulfate ions as described above can be reduced. It is possible to suppress the occurrence of clouding and a decrease in haze due to the reaction between the ammonia and the ammonia.

The size of the frame 2 and its opening 2a is determined according to the size of the OAS 21. When the frame 2 has a rectangular shape consisting of a pair of long sides and a pair of short sides when viewed from the front, the long side length is 300 mm to 1000 mm, the short side length is 300 mm to 1000 mm, and the long side and The width of each short side may be 4.0 mm to 50.0 mm, and/or the height of the frame may be 1.5 mm to 12.0 mm.

In the frame 2, the ratio (t/w) of the thickness (indicated by t in FIG. 1) to the width (indicated by w in FIG. 1) is preferably 30% or less.
Since there are restrictions on the thickness of the space in which the dust-proof structure 1 can be attached (for example, the gap between members, indicated by s in FIG. 3), by making the frame 2 thinner, it is easier to attach the dust-proof structure 1 to the alignment unit. In addition to overcoming the spatial constraints of Further, since the dustproof structure 1 is thin, the influence on alignment accuracy by the OAS 21 can be suppressed to a small extent.
Note that the lower limit of the ratio of the thickness to the width (t/w) of the frame 2 is preferably 5% or more from the viewpoint of rigidity and suppression of distortion.
When the frame 2 has different widths depending on the sides, it is preferable that the ratio of thickness to width (t/w) in at least one of the sides is within the above range.

The flatness of the frame 2 is preferably greater than 0 and less than or equal to 200 μm, more preferably greater than 0 and less than or equal to 150 μm.
Note that in this specification, "flatness" is a measured value of the waviness of the frame 2 from the stone surface plate. For example, the frame 2 is placed on a stone surface plate, a laser is applied from the top of the frame 2 (on the opposite side of the stone surface plate), and the thickness is measured using a laser displacement meter. The stone surface plate is set as the zero point, and the distance from the frame 2 on the light incident side to the stone surface plate is measured. Here, the number of measurements is five on one side, and measurements are made at each point 20 mm from both ends of the side, and further, three points are measured at equal intervals between them. This is done on four sides, and the difference in height between the highest point and the lowest point from the zero point on the four sides is the flatness value.
By having the flatness of the frame body 2 within the above range, the dustproof structure becomes less flexible when attached to the alignment unit.

The dustproof film 3 is a transparent thin film (pellicle) that prevents dust from adhering to the alignment unit without interfering with the optical function of the alignment unit.
As shown in FIG. 1(b), the dustproof film 3 is stretched, adhered, and fixed on one side of the frame 2 so as to cover the opening 2a with an adhesive (not shown).

The dustproof film 3 preferably has a transmittance of 80% or more at an incident angle of -10° to 10° for light with a wavelength of 440 to 780 nm. In other words, it is preferable that the dustproof film 3 has a transmittance of 80% or more at an incident angle of −10° to 10° for any light having a wavelength of 440 to 780 nm.
Thereby, the light emitted by the OAS alignment light source can be sufficiently transmitted, and faster and more accurate OAS alignment can be performed.

It is preferable that the amount of sagging of the dustproof film 3 is between −3.0 mm and +3.0 mm. In addition, in this specification, "the amount of looseness of the dustproof film 3" refers to a value that can be measured as follows. That is, as shown in Fig. 1, the frame has an outer diameter of 200 mm x 600 mm, the long side width is 10 mm, the short side width (w in Fig. 1 (b)) is 10 mm, and the height (Fig. 1 An aluminum alloy frame 2 whose surface is alumite-treated and has a thickness t) of 3 mm in (b) is prepared. A film adhesive is applied to one side of the prepared aluminum alloy frame 2, and a dustproof film 3 is expanded. Double-sided tape is pasted on the opposite side to which the dust-proof film 3 is stretched, and it is pasted on an acrylic plate that is one size larger than the frame body 2. With the dust-proof membrane 3 facing down, the electric fan blows air along the membrane in a weak mode. This is the value measured using a laser displacement meter at the most deflected part when air is being blown.
Regarding the amount of flap, a negative value indicates that the dust-proof film 3 is on the opening 2a side (the dust-proof structure is attached to an acrylic plate) with the virtual plane passing through the side of the frame 2 on which the dust-proof film 3 is extended as a reference (0 mm). The amount of deflection of the dustproof film 3 toward the side opposite to the opening 2a is shown, and a positive value indicates the amount of deflection of the dustproof film 3 toward the side opposite to the opening 2a.

As shown in FIG. 3, the OAS 21 is placed on the substrate 13 on which the photosensitive layer 13a (resist) is formed. Since the OAS 21 is arranged independently of the plate movement system, the OAS 21 itself does not move when the substrate stage 14 moves, but the substrate 13 placed on the substrate stage 14 moves, and at this time, it moves quite quickly. Move at speed. As shown by s in FIG. 3, the thickness of the space in which the dustproof structure 1 is attached is very small, and the distance between the dustproof structure 1 (dustproof film 3) and the photosensitive layer 13a (resist) on the surface of the substrate 13 is several. It is only about mm. Therefore, the dustproof film 3 flaps due to the wind pressure generated by the high-speed movement of the substrate 13.

If the amount of sagging of the dustproof film 3 is large, there is a risk that the dustproof film 3 will come into contact with the resist. By setting the amount of flap of the dustproof film 3 within the above range, it is possible to prevent the dustproof film 3 from coming into contact with other members.

The material constituting such a dust-proof film 3 is not particularly limited as long as it is a transparent thin film, but for example, nitrocellulose, cellulose derivatives, and fluorine polymers are preferable. As a result, the light emitted from the light source can be sufficiently transmitted during OAS alignment, and the amount of fluttering can be kept small, for example, within the above range.

The thickness of the dustproof film 3 is preferably 1.5 μm to 8.0 μm. As a result, the light emitted from the light source can be sufficiently transmitted during OAS alignment, and the amount of fluttering can be kept small, for example, within the above range.

It is preferable that the frame 2 and the dustproof membrane 3 have different natural frequencies. This can prevent the frame 2 of the dustproof structure 1 and the dustproof film 3 from resonating due to the vibration of the alignment unit.

The fixing portion is a means for mechanically fixing the dustproof structure 1 to the alignment unit, and is formed integrally with the frame 2 in this embodiment.
Note that in this specification, the "fixing part" is a frame surface that corresponds to a screw or clip when fixing the dustproof structure 1 to the alignment unit using a screw or clip. In other words, the screw or clip is not the fixing part, but the frame surface forming the screw hole or the frame surface to which the clip is attached is the "fixing part".
Furthermore, in this specification, the term "mechanical fixing means" refers to fixing means other than adhesive fixing using an adhesive, and the means is not particularly limited. According to the mechanical fixing means, the dustproof structure 1 can be attached to the alignment unit more reliably than fixing with an adhesive, and the dustproof structure 1 can be prevented from falling. Furthermore, the mechanical fixing means can avoid a situation in which the adhesive component scatters.
In this embodiment, the other side of the frame 2 is a non-adhesive surface on which no adhesive layer (layer containing adhesive or adhesive tape) is formed.

In this embodiment, a screw hole 4a and/or a screw groove 4b as a fixing part is formed in the frame 2, and the dustproof structure 1 is fixed to the OAS 21 with screws.

In this embodiment, a plurality of screw holes 4a and screw grooves 4b are formed through the frame 2, screws (external screws) are inserted through the screw holes 4a and screw grooves 4b, and screws formed on the OAS side are inserted. The dustproof structure 1 is attached to the OAS 21 by screwing into the hole (female thread) and screw hole (female thread). With screws, the fixing force can be easily adjusted by adjusting the tightening strength, and it is possible to prevent the dustproof structure 1 from falling. In addition, simple fixing (temporary fixing) during installation is also possible. In the example shown in FIG. 1, in order to absorb distortion of the dustproof structure 1 due to screw fixation, thread grooves 4b (planar U-shaped) are used in combination with some of the threaded holes 4a. .

From the viewpoint of easily absorbing distortion of the dustproof structure 1 due to screw fixation, it is preferable that the fixing parts facing each other across the opening 2a have the same type of configuration. That is, when the frame 2 has a rectangular shape having long sides and short sides, for example, the fixing part arranged on the short side part and the fixing part arranged on the long side part have the same type of structure. It is preferable to have. In the dustproof structure 1 of the present embodiment, the fixing portions having the screw holes 4a (the fixing portions arranged on the short side portions) face each other across the opening 2a, and the fixing portions having the screw grooves 4b ( The fixing parts arranged on the long sides are facing each other.

In this embodiment, one side of the frame 2 has a part where the dustproof film 3 is arranged and a part where the dustproof film 3 is not arranged, and the fixing part is on the one side of the frame 2. It is provided in the part where the dustproof film 3 is not arranged. That is, in this embodiment, one side of the frame 2 has a part where the dustproof film 3 is arranged and a part where the dustproof film 3 is not arranged, and the one side of the frame 2 has A screw hole 4a and a screw groove 4b are provided so as to penetrate through a portion where the dustproof membrane 3 is not provided. According to this, it becomes easy to suppress the occurrence of deflection of the dustproof membrane 3 due to the work of fixing or loosening the screws.

Comparing the screw holes 4a and the screw grooves 4b, the screw grooves 4b with open holes often apply less force to the frame 2 when tightened to the same extent. On the other hand, it is desirable that the dustproof structure 1 be securely fixed to the OAS 21. Therefore, from the viewpoint of reliably fixing the dustproof structure 1 to the OAS 21 while reducing the distortion of the frame 2, when the frame 2 is, for example, rectangular with long sides and short sides, the screw holes 4a are It is preferable that the fixing portion having the thread groove 4b be disposed on the short side portion and the fixing portion having the thread groove 4b being disposed on the long side portion.

It is preferable that the fixing parts are arranged to face each other with the opening 2a in between. As described above, the frame body 2 can have an outer shape such as a square, a polygon, a circle, or an ellipse when viewed from the front. Regardless of the shape, the dustproof structure 1 can be more suitably fixed to the OA 21 by disposing the fixing portions facing each other with the opening 2a in between.

The dustproof structure 1 preferably includes the same or different fixing parts in a range of 2 or more and 16 or less in total, and more preferably in a range of 4 or more and 10 or less in total. The dustproof structure 1 of this embodiment includes a total of eight fixing parts (screw holes 4a and/or thread grooves 4b), which allows the dustproof structure 1 to be more suitably fixed to the OAS 21. .

Examples of mechanical fixing means other than screws include fixing means using rivets, bolts and nuts, and various fastener materials (eg, quick fasteners, etc.). When mechanical fixing means other than screws are used, the fixing part includes a receiving part for receiving the mechanical fixing means other than screws. For example, when the dust-proof structure 1 is mechanically fixed to the alignment unit using a mechanical fixing means other than screws, the receiving portion is configured to have a surface that is in contact with at least the frame 2 (the mechanical fixing means other than screws is A concave portion and/or a convex portion including a shape corresponding to the surface in contact with the surface).

Although the embodiments of the present invention have been described above, the present invention is not limited thereto, and can be modified as appropriate without departing from the spirit of the invention.

For example, FIG. 4 is a diagram for explaining a dustproof structure according to another embodiment of the present invention. Among these, in FIG. 4(a), compared to the dustproof structure 1 shown in FIG. 1, all the fixing parts are configured as screw holes 4a. Moreover, in FIG. 4(b), compared to the dustproof structure 1, all the fixing parts are configured as thread grooves 4b. Like the dustproof structure 1, either dustproof structure is suitable as a dustproof cover for an OAS type alignment unit.

(Embodiment 2)
The dustproof structure according to Embodiment 2 of the present invention differs from the dustproof structure according to Embodiment 1 described above in the structure of the frame body. The dustproof structure according to Embodiment 2 will be described below, while omitting the explanation of parts that can use the same configuration as the dustproof structure according to Embodiment 1.
FIG. 5 is a diagram schematically showing a configuration example of a dustproof structure according to Embodiment 2 of the present invention.

The frame 2A of the dustproof structure 1A according to the second embodiment includes an inner frame (inner peripheral part) 2b forming an opening 2a, and an outer frame (outer part) 2c disposed outside the inner frame 2b. , is provided. The outer frame body 2c projects outward from a part of the side surface of the inner frame body 2b. The outer frame body 2c and the inner frame body 2b are integrally constructed, and the thickness of the outer frame body 2c is thinner than the thickness of the inner frame body 2b. The surface of the outer frame 2c on the side to be attached to the alignment unit and the surface of the inner frame 2b on the side to be attached to the alignment unit are continuous, and the surface of the dustproof structure 1A on the side to be attached to the alignment unit is continuous. It makes up the surface. That is, since the thickness of the inner frame 2b (corresponding to the thickness t in FIG. 1(b)) is greater than the thickness of the outer frame 2c, the dustproof surface of the inner frame 2b on the dustproof membrane 3 side and the outer frame 2c are A step is formed between the surface on the membrane 3 side and the surface on the membrane 3 side. The outer peripheral side surface of the inner frame 2b is continuous between the surface of the inner frame 2b on the dustproof membrane 3 side and the surface of the outer frame 2c on the dustproof membrane 3 side. By having such a configuration, it becomes easy to realize a configuration suitable as a dustproof cover for an OAS type alignment unit.

The outer frame 2c can continuously surround the outer periphery of the inner frame 2b, but it can also not surround the outer periphery of the inner frame 2b. When the outer frame 2c does not surround the outer periphery of the inner frame 2b, a plurality of outer frames 2c are discontinuously arranged from the inner frame 2b to the outer periphery at predetermined intervals along the outer periphery of the inner frame 2b. A protruding shape is formed. In the above, the outer frame body 2c and the inner frame body 2b are configured as one body, but the outer frame body 2c and the inner frame body 2b may be configured as separate bodies. Having such a configuration also makes it easier to realize a suitable configuration as a dustproof cover for an OAS type alignment unit.

The dust-proof film 3 is supported in a stretched manner on the surface of the inner frame body 2b on the dust-proof film 3 side. The outer frame 2c has a fixing part defining a screw hole 4a and/or a screw groove 4b for mechanically fixing the dustproof structure 1A to the alignment unit. Specifically, a screw hole 4a and a screw groove 4b are provided so as to penetrate the outer frame 2c in the height direction (direction along the thickness t in FIG. 1(b)). This makes it easier to realize a suitable configuration as a dustproof cover for an OAS type alignment unit. Although the screw hole 4a and the screw groove 4b are provided here, the screw hole 4a or the screw groove 4b may not be provided.

Further, the dustproof structure 1A according to the second embodiment has a suspension receiving portion including a step and/or an inclination that allows the dustproof structure 1A to be lifted.
For example, in the example shown in FIG. A recessed portion 5a recessed toward the opening 2a is formed in the formed side surface as a suspension receiving portion. The recessed portion 5a is formed continuously, and here, the recessed portion 5a that goes around the circumferential direction of the frame 2A is formed. This makes it easier to mechanically handle the dustproof structure 1A, such as being able to lift and move a jig or the like while hooking it into the recess 5a.

The recessed portion 5a can also be formed discontinuously on the outer peripheral side surface of the inner frame body 2b. In this case, it is preferable that the frame 2A of the dustproof structure 1A has a plurality of discontinuous recesses 5a. At this time, it is preferable that the recesses (discontinuous recesses) 5a formed on the pair of short sides form a pair of recesses 5a, and the recesses (discontinuous recesses) formed on the pair of long sides respectively. It is preferable that the recesses 5a form a pair of recesses 5a. This also makes it easier to mechanically handle the dustproof structure 1A, such as being able to lift and move a jig or the like while hooking it into the recess 5a.

In addition, as another form of the suspension receiving part, in the example shown in FIG. At least a part of the surface (outer peripheral side surface of the inner frame body 2b) is formed with a widened portion whose width increases as the distance from the outer frame body 2c increases. Here, a tapered part 5b whose width gradually increases as it moves away from the outer frame body 2c is formed as a widened part. Here, a tapered portion 5b that continuously goes around the frame 2 in the circumferential direction is formed. Note that the widened portion also includes a stepped shape whose width increases discontinuously as it moves away from the outer frame body 2c.

In addition, in the example shown in FIG. 6(b), as the suspension receiving part, a surface between the surface of the inner frame body 2b on the dust-proof membrane 3 side and the surface of the outer frame body 2c on the dust-proof membrane 3 side (inner frame A convex portion 5c is formed on the outer circumferential side surface of the body 2b, protruding toward the side opposite to the opening 2a. Here, a convex portion 5c is formed that extends continuously in the circumferential direction of the frame 2A.

In addition, in the example shown in FIG. 6(c), as the suspension receiving portion, a surface between the surface of the inner frame body 2b on the dust-proof membrane 3 side and the surface of the outer frame body 2c on the dust-proof membrane 3 side (inner frame A recess 5d recessed in a step-like manner toward the opening 2a is formed on the outer circumferential side surface of the body 2b. Here, a recessed portion 5d is formed that extends continuously around the circumferential direction of the frame 2A.

This makes it easier to mechanically handle the dustproof structure 1A, such as being able to lift or move a jig or the like while hooking it on the tapered portion 5b, the convex portion 5c, or the concave portion 5d. These tapered portions 5b, convex portions 5c, and recessed portions 5d can be arranged in the same manner as the recessed portions 5a described above, except that their cross-sectional shapes are different.

These tapered portions 5b, convex portions 5c, or recessed portions 5d may be discontinuously formed on the outer peripheral side surface of the inner frame body 2b. At this time, the tapered portions 5b, convex portions 5c, or recessed portions 5d (discontinuous tapered portions 5b, convex portions 5c, or recessed portions 5d) formed on the pair of short sides, respectively, It is preferable to form a concave portion 5d, and the taper portion 5b, convex portion 5c, or concave portion 5d (discontinuous taper portion 5b, convex portion 5c, or concave portion 5d) formed on the pair of long sides respectively It is preferable to form a tapered portion 5b, a convex portion 5c, or a concave portion 5d.

In addition, the surface of the dustproof structure 1A that is attached to the alignment unit (the surface of the outer frame 2c that is attached to the alignment unit, and the surface of the inner frame 2b that is attached to the alignment unit) has a slider. A valley (not shown) may be formed. On the other hand, the alignment unit is formed with a slide peak corresponding to the slide valley described above. The slide trough of the dustproof structure 1A can be guided by the slide peak of the alignment unit, and if necessary, the dustproof structure 1A can be slid on the alignment unit. This makes it easier to align the dustproof structure 1A and the alignment unit, and to mechanically fix them both. Note that a slide peak portion may be provided on the dustproof structure 1A side, and a slide trough portion may be provided on the alignment unit side. The above-mentioned effects can be easily obtained by providing mutually corresponding slide valleys and slide peaks on the dustproof structure 1A side and the alignment unit side, respectively.

As shown in FIG. 7, in the dustproof structure 1A according to the second embodiment, the following (1) to (3 ) is preferably included.
(1) The width T1 of the portion of the dustproof film 3 that is stretched and supported by the inner frame (inner circumference) 2b exceeds the thickness H1 of the inner frame (inner circumference) 2b (T1>H1>0).
(2) The thickness H2 of the outer frame body (outer part) 2c is 1/2 or less (1/2·H1≧H2>0) of the thickness H1 of the inner frame body (inner peripheral part) 2b.
(3) The ratio (T2/T3) of the total width T2 of the inner frame body (inner peripheral part) 2b and the outer frame body (outer part) 2c to the screw receiving width T3 of the opening of the screw hole 4a or thread groove 4b is 1 It is within the range of ~13.

(1) By ensuring a large adhesion area for the dustproof film 3 due to T1 being large, it becomes easier to suppress flapping of the dustproof film 3 even when the stage moves at high speed or vibrates. Furthermore, since H1 is small, the dustproof structure 1A can be set while the alignment scope is placed near the stage. The dustproof structure 1A can be set on the alignment scope even under severe spatial constraints.
(2) Since H1 is large, the rigidity of the frame 2A can be ensured. Moreover, since H2 is small, the side surface on which the suspension receiving part is formed can be secured.
(3) By setting T2/T3 within the above range, it is possible to balance the ratio of the portion on which the fixing force acts with respect to the attachment surface to the alignment unit.

The present invention, on the premise that it belongs to a technical field in which extremely high flatness is essential, has the above-mentioned structure to solve the problems peculiar to alignment applications. This is intended to prevent overall distortion and suppress a decrease in rigidity.
In this embodiment, because we focus on the above-mentioned problem, we purposely separate the screw-fastening function of the dust-proof structure 1A from the inner frame body 2b while providing the inner frame body 2b with the function of expanding the dust-proof membrane 3, and create this new function. The structure is such that the outer frame body 2c has the following structure. By arranging the suspension receiving part on the "side surface of the inner frame 2b on which the outer frame 2c is formed" that appears for the first time with this configuration, the outer frame 2c can be used as a guide for the lifting device of the dust-proof structure 1A. It was also possible to add functionality.

In the dustproof structure 1A according to the second embodiment shown in FIG. 5, all the fixing parts may be configured as screw holes 4a. Moreover, all the fixing parts may be configured as thread grooves 4b.

(Embodiment 3)
The dustproof structure according to Embodiment 3 of the present invention differs from the dustproof structure according to Embodiment 1 described above in the structure of the frame body. The dustproof structure according to Embodiment 3 will be described below, while omitting the explanation of parts that can use the same configuration as the dustproof structure according to Embodiment 1.
FIG. 8 is a diagram schematically showing a configuration example of a dustproof structure according to Embodiment 2 of the present invention.

The dustproof structure 1B of this embodiment includes a magnet 6 for fixing the dustproof structure 1B to an alignment unit.
In this embodiment, a magnet 6 as a fixing part is arranged on the frame 2B, and the dustproof structure 1B is fixed to the OAS 21 by the magnet 6. Here, the magnet 6 is formed so as to continuously go around the frame 2B in the circumferential direction.
According to the magnet, the fixing force can be easily adjusted by adjusting the strength of the magnetic force, and it is possible to prevent the dustproof structure 1 from falling. Moreover, the work at the time of installation is easy.

From the viewpoint of easily absorbing distortion of the dustproof structure 1B due to magnet fixation, it is preferable that the fixing parts facing each other across the opening 2a have the same type of configuration. That is, when the frame 2B has a rectangular shape, for example, having long sides and short sides, the fixing parts disposed on the short sides and the fixing parts disposed on the long sides each have the same type of configuration. It is preferable to have.

These magnets 6 can also be arranged discontinuously on the outer peripheral side surface of the inner frame body 2b. At this time, it is preferable that the magnets 6 (discontinuous magnets 6) arranged on the pair of short sides form a pair of magnets 6, and the magnets 6 (discontinuous magnets 6) arranged on the pair of long sides respectively form a pair of magnets 6. Preferably, the continuous magnets 6) form a pair of magnets 6.

The frame 2B provided with the magnet 6 according to the third embodiment may also be formed with a suspension receiving portion including a step and/or an inclination that allows the dustproof structure 1B to be lifted. The suspension receiving portion can have the same configuration as the recess 5a, tapered portion 5b, convex portion 5c, and stepped recess 5d mentioned in the second embodiment.

In the dustproof structure 1 of this embodiment, fixing with screws and fixing with magnets can be combined. That is, the frame body 2 (2A, 2B) may have a screw hole 4a or a screw groove 4b formed therein, and may also have a magnet 6 arranged thereon.

Embodiment 2, Embodiment 3, other embodiments related thereto, and still other embodiments described above can be combined with each other. For example, the surface between the dust-proof membrane side surface of the inner frame body and the dust-proof membrane side surface of the outer frame body (outer peripheral side surface of the inner frame body) has a concave part, a convex part, and a tapered part (widened part). and at least two of these at the same time. Furthermore, the second embodiment, the third embodiment, other embodiments related thereto, and still other embodiments described above can also be combined with the above-described first embodiment.

By using the dustproof structure according to the present invention, it becomes suitable as a dustproof cover for an OAS type alignment unit, and can be widely used as a dustproof structure for an alignment unit.

1, 1A, 1B: Dustproof structure 2, 2A, 2B: Frame 2a: Opening 2b: Inner frame (inner peripheral part)
2c: Outer frame body (outer part)
3: Dust-proof membrane 4a: Screw hole 4b: Screw groove 5a: Recess (suspension rack receiving part)
5b: Tapered part (hanging frame receiving part)
5c: Convex part (suspension rack receiving part)
5d: Recess (hanging frame receiving part)
6: Magnet 10: Exposure device 11: Mask 11a: Pattern 12: Mask stage 13: Substrate 13a: Photosensitive layer 14: Substrate stage 15: Illumination optical system 16: Concave mirror 17: Convex mirror 18: Bending mirror 20: AS (alignment scope) )
21: OAS (off-axis alignment scope)
21a: Lighting part

Claims (15)

a frame forming an opening;
a dustproof membrane stretched and supported on one side of the frame so as to cover the opening;
A dustproof structure comprising:
A dustproof structure for an alignment unit, comprising at least one of a fixing part for mechanically fixing the dustproof structure to the alignment unit, and a magnet for fixing the dustproof structure to the alignment unit. The dustproof structure according to claim 1, wherein the dustproof film has a transmittance of 80% or more at an incident angle of -10° to 10° for light with a wavelength of 440 to 780 nm. The dustproof structure according to claim 1 or 2, wherein the dustproof film has a flattening amount of -3.0 mm to +3.0 mm. One side of the frame body has a part where the dustproof film is arranged and a part where the dustproof film is not arranged,
The dustproof structure according to any one of claims 1 to 3, wherein the fixing portion is provided in a portion of one side of the frame body where the dustproof film is not provided. The dustproof structure according to any one of claims 1 to 4, wherein sulfate ions contained in the frame are 0.3 ppm or less. The dustproof structure according to any one of claims 1 to 5, wherein the other side of the frame is a non-adhesive surface on which no adhesive layer is formed. The dustproof structure according to any one of claims 1 to 6, comprising a total of 2 or more and a total of 16 or less of the fixing parts. The dustproof device according to any one of claims 1 to 7, wherein the frame includes an inner circumferential portion forming the opening, and an outer portion protruding outward from a part of a side surface of the inner circumferential portion. Structure. The dust-proof structure according to claim 8, wherein the outer part has the fixing part defining a screw groove and/or a screw hole for screw-fixing the dust-proof structure to an alignment unit. The dust-proof structure according to any one of claims 1 to 7, wherein the dust-proof structure has a suspension receiving portion including a step and/or an inclination that allows the dust-proof structure to be lifted. The dustproof structure according to claim 10, wherein the suspension receiving portion is provided on the side surface of the inner peripheral portion where the outer portion is formed. The dustproof structure according to any one of claims 1 to 11, wherein the frame has a flatness of more than 0 and less than 200 μm. The dustproof structure according to any one of claims 1 to 12, wherein the dustproof film has a thickness of 1.5 to 8.0 μm. Any one of claims 1 to 13, wherein the fixing part includes an area that includes an assumed central axis of the screw and that a cut plane view perpendicular to the dustproof film satisfies any of the following (1) to (3). The dustproof structure according to item 1.
(1) The width T1 of the part where the dustproof film is stretched and supported on the inner circumference exceeds the thickness H1 of the inner circumference (T1>H1>0)
(2) The thickness H2 of the outer part is less than or equal to 1/2 of the thickness H1 of the inner circumferential part (1/2 H1≧H2>0). The ratio (T2/T3) of the total width T2 of the peripheral part and the outer part is within the range of 1 to 13. The dustproof structure according to any one of claims 1 to 14, wherein the frame body and the dustproof film have mutually different natural frequencies.

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