JPH0348097B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a dust-proof cassette, and particularly to a dust-proof cassette for a photomask or reticle conveniently used in semiconductor manufacturing equipment.

[Conventional technology]

In the manufacturing process of semiconductor devices such as ICs, LSIs, and VLSIs, one of the issues that must be solved is the problem of dust adhesion to masks or reticles (hereinafter collectively referred to as masks). When an ultra-fine circuit pattern formed on a mask is transferred to a semiconductor wafer, if dust adheres to the mask, it may cause damage to the circuit pattern transferred to the wafer.
This not only deteriorates the performance of the semiconductor device manufactured through post-processing, but also, in the worst case, impairs the entire function of the semiconductor device.

However, in conventional semiconductor manufacturing equipment, since a worker must directly load a mask into a mask holder, there is a high possibility that dust from the human body will adhere to the mask.

In order to solve these problems, in semiconductor manufacturing equipment, a cassette for storing a mask is constructed with an upper lid and a lower lid, and after the upper lid and lower lid are separated, the mask is taken out from the lower lid and placed in a mask holder. For example, a device for automatically loading
This is proposed in Publication No. 5521, etc.

[Problems to be Solved by the Invention] Incidentally, in the mask cassette disclosed in this publication, the fork for pulling out the lower cover of the cassette set in the carrier from the upper cover is provided with a fork located above the lower cover supporting surface of the fork. It is necessary to provide an engaging piece that protrudes from the side. In addition, in this cassette, when the engaging piece comes into contact with the edge of the lower cover in order to pull out the lower cover with a fork, dust is generated, and the engaging piece of the fork protrudes upward from the lower cover supporting surface. There was a high possibility that the dust would adhere to the mask inside the lower lid.

The present invention was made in view of the above circumstances, and its purpose is to store a substrate such as a mask or reticle, and to take out the substrate automatically and without dust adhering to the substrate. The objective is to provide a dustproof cassette that makes it possible to

[Means and effects for solving the problem] In order to achieve the above-mentioned objects, the present invention provides a lower lid for placing a substrate such as a mask or a reticle, and a lower lid that is oriented in a predetermined drawing direction. It has an upper lid that is overlapped with the lower lid so that it can be pulled out, and by overlapping the lower lid and the upper lid, a sealed chamber for storing the substrate is formed, and the lower lid has a protruding piece on the outside of the side wall along the direction of the drawer. The lower surface of the protruding piece is supported by the fork that enters the underside of the protruding piece when it is held in the cassette carrier, so that the lower cover can be pulled out of the cassette carrier while leaving the upper cover inside the cassette carrier. In this dustproof cassette, a convex engagement piece that engages with a locking portion of the fork in the drawing direction is provided below the protruding piece of the lower lid.

According to the present invention, there is no need to provide the fork with a portion that projects upward from the lower cover support surface of the fork, and the contact between the fork and the lower cover is always made only on the lower side of the protruding piece of the lower cover. Therefore, even if dust is generated due to contact between the fork and the lower cover, the dust will not adhere to a substrate such as a mask or reticle.

〔Example〕

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a diagram showing the upper lid structure of the dustproof cassette of the present invention. The central part 2a of the front wall 2 of the top lid 1 protrudes compared to both ends 2b, and a flexible inverted L-shaped locking member 3 is integrally attached to each of the retracted ends 2b. There is. Hole 3 of this inverted L-shaped locking member 3
b indicates both ends 11 of the front wall 11 of the lower lid 10, which will be described later.
It fits into the locking protrusion 12 formed at the corresponding position of b. The upper lid 1 and the lower lid 10 are sufficiently sealed by the locking protrusion 12 and the locking member 3.

The surface of the central portion 2a of the front wall 2 of the upper lid 1 protrudes from the front surface 3a of the locking member 3, so that even if the dustproof cassette falls, the locking member will not be easily damaged.

Next, to explain the side walls 4 of the upper lid 1, each side wall 4 has a first side wall portion 4a having the same height as the front wall 2, and a state in which the upper lid 1 and the lower lid 10 are overlapped. The second side wall portion 4b has a height that extends to approximately the same position as the bottom of the lower lid 10.
It is composed of.

A guide groove 5 is formed inside the second side wall portion 4b and extends from the oblique side portion 4c in the horizontal direction (drawing and conveying direction). Note that the transport direction is the direction of the arrow in FIG. 2A.

Here, the guide pin 22 of the lower lid 10 is loosely fitted into the guide groove 5.

The guide groove 5 may have a structure that does not penetrate the side wall 4b in the thickness direction as shown in FIGS. 1 and 2B, or may have a structure that penetrates the side wall 4b' as shown in FIG. 2C. .

As a result, as is clear from FIGS. 2B and 2C, the position of the lower lid 10 in the direction perpendicular to the transport direction within the horizontal plane is restricted by the upper lid 1.

FIG. 3 shows a state in which the upper lid 1 and the lower lid 10 are locked by the locking member 3. As shown in FIG.

Now, returning to FIG. 1, the protruding piece 6 provided at the lower end of the side wall portion 4b of the upper lid 1 is held by a holding member 44 of a carrier for storing cassettes in multiple stages, as shown in FIG. Guide pin 22
When the guide groove 5 is located at the innermost part of the guide groove 5, the guide groove 5 can be pivoted about the position as a fulcrum.

As a result, when the locking members 3 and 12 are released, the upper cover 1 is rotated about the position 22a when the guide pin 22 is located at the innermost part of the guide groove 5 as a fulcrum, and is set at a predetermined rotation angle position. Rotation is stopped by the stopper and the slanted state is established.

Now, a stepped portion 8 is formed at the inner lower end of the rear wall 7 of the upper lid 1, and the stepped portion 8 includes the side walls 4 of the upper lid 1,
It extends between 4. In a state where the upper lid 1 and the lower lid 10 are overlapped, a lower surface 16a of a rear wall stepped portion 16 of the lower lid, which will be described later, is in contact with an upper surface 8a of the rear wall stepped portion 8 of the upper lid 1, and is supported.

FIG. 2A is a diagram showing the lower lid structure of the dustproof cassette of the present invention. Similar to the front wall 2 of the upper lid 1, the central part of the front wall 11 of the lower lid 10 protrudes compared to both ends 11b, and the retracted ends 11b are connected to both ends 2b of the front wall of the upper lid 1, respectively. A locking protrusion 12 is formed to engage with the attached inverted L-shaped locking member 3. Next, to explain the both sides 13 of the lower lid 10, when the upper lid 1 and the lower lid 10 are stacked, the protruding pieces 14 on which the lower surface 4d of the first side wall 4a of the upper lid 1 is placed are located on the side wall 13. Extending from the top end. This protruding piece 14 includes the upper cover 1 and the lower cover 1.
In order to seal the inside of the cassette when the cassettes 0 and 0 are overlapped, it is preferable that the cassette has a length substantially equal to the length of the first side wall 4a of the upper lid 1 in the transport direction.

The lower surface of this protruding piece 14 is placed by a fork section in the case of automatic conveyance, which will be described later.

Note that the upper lid 1 is attached to both side walls 13, 13 of the lower lid 10.
A guide pin 22 accommodated in a guide groove 5 formed in the second side wall portion 4b is arranged adjacent to the protruding piece 14.

A step 16 is formed at the lower end of the rear wall 15 of the lower lid 10 and has a shape corresponding to the step 8 formed at the inner lower end of the rear wall 7 of the upper lid.

Further, an annular portion 18 is arranged near the center of the interior of the lower lid 10 and stands upright from the bottom portion 17 on which a mask or reticle is placed.

The annular portion 18 and the four walls 11a, 1 of the lower lid 10
Rib 1 that is perpendicular to the approximately central portions of 3, 13, and 15.
connected by 9. Since the circular mask 20 is normally placed on the annular portion 18 with the patterned surface facing downward in the exposure apparatus, the annular portion 18
The inner rib 19a of the mask 20 has a lower height.
It is preferable to avoid contact with the patterned surface of the substrate. Further, as shown in FIG. 2A, projections 25 may be arranged at equal intervals on the upper end surface of the annular portion 18, and the mask 20 may be supported by the projections 25.

In addition, a pellicle film is often attached to the patterned surface of the mask 20 to prevent dust from adhering to it. Place it. In this case, the inner diameter of the annular portion 18 must be larger than the outer diameter of the pellicle membrane, and the inner rib 19a must be made sufficiently low in consideration of the thickness of the pellicle membrane holding member.

Around the annular portion 18, there is a perpendicular portion 19b of the rib 19.
Positioning pins 21 stand upright in a concentric circle with the center as the center. This positioning pin 21 serves to position the mask 20 approximately at the center within the lower lid 10 when the mask 20 is placed on the annular portion 18 . For this reason, it is convenient that the height of the pin 21 is set equal to or higher than the upper surface position of the mask 20 placed on the annular portion 18.

Next, the upper lid 1 and the lower lid 10 of the dustproof cassette of the present invention
The principles of how to assemble and remove will be explained with reference to FIGS. 4 to 7. Note that the explanation using the automatic conveyance system will be given with reference to FIGS. 11 to 14.

A state in which the mask 20 is placed on the annular portion 18 of the lower lid 10 with reference to the positioning pins 21 (Fig. 7)
First, remove the guide pins 2 extending from both side walls 13 of the lower cover.
2, 22 toward the guide grooves 5, 5 formed in the second side walls 4b, 4b of the upper lid 1, the rear wall 15 of the lower lid is brought closer to the rear wall 7 of the upper lid (6th
figure). When the guide pins 22, 22 are accommodated in the guide grooves 5, 5, and the lower surface 16a of the stepped portion 16 of the lower lid 10 contacts and is supported by the upper surface 8a of the rear wall stepped portion 8 of the upper lid 1 (FIG. 5), The upper cover 1 is rotated around the guide pins 22, 22.
Rotate counterclockwise. As a result, the upper lid is inverted L.
The ends of the letter-shaped locking members 3 and the locking protrusions 12 on the lower lid are engaged, and the cassette is in the assembled state as shown in FIGS. 3 and 4. To remove the upper cover and lower cover, the above-described operations may be performed in reverse order in the order shown in FIGS. 4 to 7.

Next, an automatic conveyance system for automatically conveying masks will be explained.

In FIG. 8, the dust-proof cassettes 31 are stacked on a cassette carrier 32, but a fork unit 33 supported by an elevator unit 34 that moves vertically automatically transports the predetermined dust-proof cassettes and only the lower lid with the mask attached. be done.

The vertical position of the fork unit 33 is precisely determined photoelectrically by a fixed index plate 35 and a photo switch 36 provided on the elevator unit 34, as shown in FIGS. 15A and 15B.
This ensures stable locking and unlocking of the upper and lower lids by vertical movement of a fork unit 33, which will be described later.

The lower lid of a predetermined dustproof cassette taken out from the cassette carrier 32 is carried by an elevator unit 34 to an upper mask alignment stage 38, where the mask is sucked by a mask hand unit 37 and carried to an exposure stage.

FIG. 9 shows the flow of the mask described above. In FIG. 9, 39 is a mask, 40 is a mask position detection unit, 41 is a mask loader, and 42 is an exposure position.

FIG. 10 is a diagram showing the appearance of the fork unit 33.

The forks 33a and 33b are attached to both side walls 1 of the lower lid 10.
The lower surface of the protruding piece 14 of the lower lid 10 is placed on the lower surface of the protruding piece 14 of the lower lid 10.

FIGS. 11 to 14 show automatic mask conveyance using the fork unit 33 described above.

FIG. 11 shows the fork unit 33 moved horizontally so as to approach a predetermined dustproof cassette.

At this time, regarding the dust-proof cassette, the protruding piece 6 of the upper lid 1 is held by the carrier's holding member 44, and the upper lid 1 and the lower lid 10 are integrated by the locking members 3 and 12, so the dust-proof cassette is integrally attached to the carrier. Therefore, it is in a supported and fixed state.

Note that the protruding piece 14 of the lower lid is held by a guide bearing 43 of the carrier.

Next, in FIG. 12, the fork unit 33 is shifted upward by several mm by the elevator unit 34 (the fork unit 33 supports the lower surface of the protruding piece 14 of the lower cover 10, and the bearing 46 in the fork unit 33 is moved upward by the locking member 34). , 12 are unlocked.

The upper lid 1 is supported at the fulcrum 22a by the urging force of the spring 45.
It rotates clockwise around , and its position in the rotational direction is regulated by a stopper (not shown), and it stops in a diagonally raised position as shown in the figure.

Note that the fulcrum 22a is the position when the guide pin 22 is at the innermost part of the guide groove 5.

FIG. 13 shows that the fork unit 33 places the lower lid 10 and retreats in the horizontal direction, that is, the lower lid 10
This shows the state in which it is pulled out. The vertical position of the fork unit 33 in FIG. 13 is the same as in FIG. 12.

Further, when pulling out the lower lid 10, an engaging piece 51 provided in a convex shape below the protruding piece 14 of the lower lid 10
(see Fig. 11) engages with the concave locking portions 50 (see Fig. 11) provided on the forks 33a, b (see Fig. 8), so that the lower cover 10 is placed on the fork unit 33 in the drawing direction. location is regulated.

FIG. 14 shows a state in which the fork unit 33 has reached the retracted position.

Thereafter, the lower lid 10 is carried to the uppermost position by the elevator unit 34, and the mask reaches under the mask hand unit 37.

The above is the order in which the mask is removed by the automatic transport system, but when inserting the mask into the dustproof cassette, the flow described above is reversed. That is, the mask is placed on the lower lid 10 and the fork unit 3
3, the guide pin 22 of the lower cover 10 reaches the innermost part of the guide groove 5 of the upper cover 1.

When the fork unit 33 is shifted downward, the claw portion 47 of the fork shift 33 pushes down the locking member 3, so the top cover 1 rotates counterclockwise around the fulcrum 22a, and the locking member 3 of the top cover 1 moves downward. It engages with the protrusion 12 of the lid 10, and the upper lid 1 and the lower lid 10 are integrated.

The fork unit 33 then retreats horizontally from the downwardly shifted position.

Here, index board 35 and photo switch 3
Fig. 15A shows the detection of the vertical position of the fork using 6.
Shown in B.

Four photo switches 36a to 36d are provided in the elevator unit 34 for a fixed index plate 35.

In FIG. 15A, the photo switches 36a' to 36d' show the positions in which the fork unit 33 has been shifted downward by Δ in order to close the top cover 1.

FIG. 15B is a view taken in a direction perpendicular to the paper surface of FIG.
This shows a state in which the light from P is blocked by the index plate 35 and does not reach the light receiving section 36q, resulting in no output.

The vertically low position of the fork unit 33 (see FIG. 11) is detected by the photo switches 36b' and 36c', while the vertically high position of the fork unit 33 (see FIGS. 12 to 14) is detected by the photo switches 36a and 36d. Detected in

In the figure, l ₁ and l ₂ are the lengths of the light-shielding part and the opening of the index plate 35, respectively, and the two have different absolute values, and (l ₁ + l ₂ ) is the length of the cassette carrier 32.
corresponds to each interval of the cassette storage positions.

Now, various modifications can be made to the above embodiment.

For example, in FIG. 3, the abutting surfaces of the front wall 2 of the upper lid 1 and the front wall 11 of the lower lid 10 are flat walls, but they may have different height shapes as shown in FIGS. 4 to 7. Further, the rear wall of the upper lid 1 may be recessed to allow easy access for human hands, as shown in FIGS. 11 to 14. This makes it easy to manually set the dustproof cassette in the cassette carrier.

Furthermore, when the upper and lower lids are overlapped and the mask is stored in the cassette, a pad 24 is provided on the upper lid to prevent the mask from shifting inadvertently and damaging the mask surface.
(Fig. 7) may also be provided.

The material for the top and bottom lids of the dustproof cassette is
A resin called PEEK (Poly Ether Ether Ketone) is preferred. This is because in the unlikely event that dirt, oil, etc. adhere to the cassette, the cassette must be cleaned, but PEEK is not easily damaged by various cleaning solutions, and it also has excellent mechanical strength.

In the above embodiments, the mask is circular, but it goes without saying that it may also be square.

〔Effect of the invention〕

As described above, according to the dust-proof cassette of the present invention, there is no need to provide the fork with a part that projects upward from the lower cover support surface of the fork, and the contact between the fork and the lower cover is always on the lower side of the protruding piece of the lower cover. Even if dust is generated due to contact between the fork and the lower cover, the dust will not adhere to the substrate such as the mask or reticle. Therefore,
According to the dust-proof cassette of the present invention, it is possible to automatically take out a substrate such as a mask or a reticle without dust adhering to the substrate.

[Brief explanation of drawings]

Figure 1 is a perspective view of the upper lid structure of the dust-proof cassette of the present invention, Figure 2A is a perspective view of the lower lid structure of the dust-proof cassette of the present invention, and Figures 2B and C are cross-sections of the dust-proof cassette seen from the transport direction. Figures 3 and 3 show the dust-proof cassette of the present invention in a combined state, and Figures 4 to 7 show the dust-proof cassette of the present invention with its upper and lower lids separated and placed on the lower lid. An explanatory diagram of the principle of conveying a plate-shaped object. Figure 8 is a schematic diagram of the automatic conveyance system. Figure 9 is a diagram showing the movement (flow) of the plate-shaped body by the automatic conveyance system. Figure 10 is the automatic conveyance system. Figures 11 to 14 are explanatory diagrams in the case where the upper and lower lids of the dust-proof cassette are separated and the plate-shaped object placed on the lower lid is automatically transported using an automatic transport system. , Figure 15 A, B
is an explanatory diagram of how to detect the vertical position of the fork using the index board and photo switch. In the figure, 1 is the upper cover, 2 is the lower cover, 13 is the side wall, and 14
20 is a protruding piece, 20 is a mask, 32 is a cassette carrier, 33 is a fork unit, 50 is a locking part, 5
1 is an engagement piece.

Claims (1)

[Claims] 1. A device comprising a lower lid 10 on which a substrate 20 such as a mask or a reticle is placed, and an upper lid 1 that is overlapped with the lower lid so that the lower lid can be pulled out in a predetermined drawing direction. By overlapping the lower lid and the upper lid, a sealed chamber for accommodating the substrate is formed, and the lower lid has a side wall 13 along the drawing direction.
A protruding piece 14 is provided on the outside of the cassette carrier 3.
2, the lower surface of the protruding piece is supported by the fork 33 that enters the lower side of the protruding piece, so that the lower cover can be inserted into the cassette carrier while leaving the upper cover in the cassette carrier. In the dustproof cassette that can be pulled out, the lower lid has a convex engaging piece 51 below the protruding piece that engages with the locking part 50 of the fork in the pulling direction. A dustproof cassette.