JPH0423317Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a wafer cassette for transporting and setting sample wafers onto, for example, a table of an electron beam exposure apparatus.

[Technical background of the invention and its problems]

When drawing multiple layer patterns directly on a wafer using an electron beam exposure device, the desired pattern cannot be obtained unless the first layer pattern and the subsequent layer patterns are overlapped and drawn as desired. Therefore, the sample wafer needs to be loaded onto the sample table of the exposure apparatus in the same posture as when drawing the first layer and when drawing the subsequent layers. Then, a mark search function using an electron beam corrects some errors and performs drawing in a state equivalent to the ideal state, but the permissible specimen posture at this time is approximately 1 to 2 × 10 ^-4 rad with rotational accuracy. This is a small value.

Conventionally, a notch provided at one end of the wafer was pressed against a reference protrusion of the wafer cassette by a clamper, so that the wafer was attached to the wafer cassette in a predetermined posture, and this was then set on the sample table. Since the clamper of the wafer cassette could only be moved in the pressing direction, the friction between the clamper and the wafer, as well as between the wafer and the reference protrusion, could prevent the wafer from rotating. The posture of the wafer changes each time it is loaded into the cassette. Therefore,
Conventionally, the wafer was rotated on a sample table to adjust the deviation in the rotation direction.

However, a special rotation mechanism is required to rotate the wafer on the sample table, which has the disadvantage of complicating the structure of the apparatus and wasting the time for centering the wafer.

Note that the displacement of the wafer in the X and Y directions is kept within a predetermined error range by moving the sample table.

[Purpose of invention]

This invention was made with attention to the above circumstances,
The object of the present invention is to provide a wafer cassette which has a simple structure and allows the rotational direction of the wafer to be set easily and accurately.

[Summary of the idea]

In order to achieve the above object, the present invention includes a clamper that presses a notch provided at one end of the wafer against a reference protrusion provided on the wafer placement surface of the cassette body.
movable by a predetermined amount not only in the pressing direction but also in a direction perpendicular to the pressing direction within the wafer mounting surface;
The notch portion of the wafer can be held in secure contact with the reference protrusion.

[Example of idea]

Hereinafter, the present invention will be described with reference to an embodiment shown in the drawings. In the figure, reference numeral 1 denotes a cassette body, and the upper surface of this cassette body 1 serves as a wafer mounting surface 1a. A reference protrusion 2 is provided protruding from one side of the wafer placement surface 1a, and a through hole 3 is provided on the other side. Further, a clamper 4 is provided within the cassette body 1, and this clamper 4 is biased by a spring 5 as a biasing member, and is pulled to the left in FIGS. 1 and 2. . The tip of the clamper 4 is bent into an L-shape and projects through the through hole 3 onto the wafer mounting surface 1a. This clamper 4 has a spring 5
It is possible to move freely not only in the biasing direction by the biasing direction, but also in a direction perpendicular to the biasing direction within the through hole 3 along the wafer mounting surface 1a, as shown by the arrow in FIG. .

Thus, the wafer 6 is placed on the wafer placement surface 1a of the cassette body 1 with its notch 6a facing the reference protrusion 2, and the tip of the clamper 4 is locked to the other end so that the wafer 6 is elastic. At this time, the clamper 4 can move freely in the direction of the arrow shown in FIG. As a result, the notch 6a of the wafer 6 is easily and reliably brought into contact with the reference protrusion 2 and held.

In this manner, the wafer 6 held in the cassette body 1 is transferred onto the sample table of an electron beam exposure apparatus (not shown), and desired patterns are sequentially formed.

As mentioned above, the reference protrusion 2 on the cassette body
In order to transport the wafer 6 onto the sample table with the notch 6a of the wafer 6 securely aligned and fixed, the wafer 6 is automatically placed on the sample table in a predetermined position by aligning the cassette body 1 with the reference mark on the sample table. can be set to Therefore,
There is no need to adjust the deviation in the rotational direction of the wafer 6 on the sample table, there is no need to take time to adjust the position in the rotational direction, there is no need for a special rotation mechanism for the wafer 6, and the structure is improved. It can also be simplified.

[Effect of idea]

As explained above, the present invention has a cassette body protruding from a reference protrusion and is also provided with a clamper, which presses the wafers placed on the cassette body so that the notch of the wafer is pressed against the reference protrusion. In a wafer cassette that is held in contact with the wafer cassette, the wafer can be held in a predetermined posture relative to the wafer cassette, so it is no longer necessary to adjust the deviation in the rotational direction of the wafer on the table as in the past. This eliminates the need for wafer positioning, which simplifies the structure of the device and shortens the time required to position the wafer. In addition, no slipping occurs at the contact point between the clamper and the wafer, and the generation of dust due to slipping is prevented, so that the wafer can be processed satisfactorily.

Furthermore, since the clamper moves passively in accordance with the movement of the wafer, no special driving source is required, resulting in a simplified structure and cost reduction.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a plan view showing a wafer cassette, and FIG. 2 is a side sectional view thereof. 1...Cassette body, 1a...Wafer placement surface,
2... Reference protrusion, 4... Clamper, 6... Wafer, 6a... Notch.

Claims (1)

[Scope of utility model registration request] A cassette body having a notch at one end on which a wafer is placed; a reference protrusion protruding from the wafer placement surface of the cassette body; and a clamper that elastically presses the wafer and holds the wafer by bringing its notch into contact with the reference protrusion, the clamper moving in a direction perpendicular to the pressing direction within the wafer placement surface. 1. A wafer cassette, wherein the wafer cassette is provided to be movable by a predetermined amount, and is driven to move in accordance with the movement of the wafer when the wafer comes into contact with the reference protrusion.