JPH04174507A - Photomask transferring equipment - Google Patents

Abstract

PURPOSE:To eliminate vacuum leak when a thin substrate is used, and improve the utilization of a recycle substrate, by installing a seal for plate thickness correction corresponding with the irregularity of thickness of a substrate for copy use so as to be detachable. CONSTITUTION:A master mask 13 is brought into contact with a substrate 14 for copy use on which an image of the mask 13 is to be transferred, and retained by vacuum suction via an elastic seal in a printing room 15. When an image is transferred by exposure to light, a seal 12 for plate thickness correction is installed so as to be detachable. That is, when a thin substrate 14 of about 2.0-2.2mm in thickness is used, the seal 12 for plate thickness correction of 0.1-0.5mm in thickness is fixed on the elastic material seal 11, and the mask 13 and the substrate 14 are subjected to vacuum suction. By fixing the seal 12 corresponding with the thickness irregularity of the substrate 14 so as to be detachable, the vacuum leak when the thick substrate 14 is used can be eliminated, so that the utilization factor of a recycle substrate can be increased by about 20%.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photomask transfer device, and more particularly to a photomask exposure device used in a photolithography process for semiconductor integrated circuits.

[Conventional technology]

2. Description of the Related Art As one type of photomask exposure apparatus used during the photolithography process of semiconductor integrated circuits, there is a transfer apparatus for obtaining a plurality of copy masks from a master mask.

One type of such conventional transfer apparatus is a type called a contact printer in which a master mask and a copying substrate to which the image thereof is transferred by exposure are brought into close contact.

In this device, as shown in the cross-sectional schematic diagram of FIG.
In order to irradiate parallel ultraviolet rays 39, the mask and substrate, which are held in close contact with each other, are vacuum-adsorbed to an elastic seal 31 attached to the printing frame 35.

Next, the manufacturing process of a copy mask using a contact printer will be explained based on the schematic cross-sectional views of FIGS. 4(a) to 4(f). First, on a glass substrate 41 (for example, quartz or soda lime) with a thickness of 2.3 mm,
Clean the copying substrate on which chromium 42 has been deposited to a thickness of 0 A. (a) 0 Next, resist 44 is coated with
Pre-baking is performed after coating to a thickness of 6,000 people (b). After that, using the contact printer mentioned above, the pattern of the master mask 43 is exposed all at once onto the copy substrate (
C). Set this substrate in the developing device and apply 100 to 400
While rotating at rpm, a developer is sprayed onto the resist 44 to dissolve and remove unnecessary portions of the resist 44 (d). After performing a boss bake to strengthen the adhesion between the chromium 42 and the resist 44, the resist 4 is immersed in an etching solution containing ceric ammonium nitrate and perchloric acid as main components.
Etch the chromium 42 in the area where 4 has been removed (e
). Finally, the resist 44 is removed using a stripping solution to complete the photomask (f).

Conventionally, copy photomasks made through the above-described manufacturing process have been used to transfer patterns onto wafers and then discarded. However, when using an expensive material such as quartz as a substrate, recycling has begun to be used to reduce costs. That is, after etching and removing the chrome pattern on the used photomask, the quartz substrate is re-polished by 10 to 100 μm, and then the chromium is
0 to 1200A is deposited and reused according to the manufacturing process shown in FIG.

[Problem to be solved by the invention]

However, since recycled quartz substrates are thinner than the original thickness of 2.3 mm, they are approximately 2.0 to 2.2 mm thick, so in the conventional contact printers described above, the seal and plate (mask or substrate) are thinner than the original thickness of 2.3 mm. Another problem is that vacuum leaks through the gap, causing poor adhesion between the mask and the substrate, making printing impossible.

The present invention has been made in view of the above-mentioned disadvantages of the conventional apparatus, and an object of the present invention is to provide a photomask transfer apparatus that can cope with variations in the thickness of the substrate.

[Means to solve the problem]

The photomask transfer device of the present invention brings a master mask and a copying substrate to which an image of the master mask is to be transferred into close contact with each other, holds the master mask on a printing frame by vacuum suction via an elastic seal, and transfers the image by exposure to the photomask. The transfer device is removably equipped with a plate thickness correction seal that corresponds to variations in the thickness of the copy substrate.

〔Example〕

The present invention will be explained in detail below using the drawings. Figure 1 (a
) is a schematic cross-sectional view of a portion of a contact printer that is an embodiment of the mask transfer device according to the present invention, which holds a master mask and a copying substrate in close contact; FIG. be. When using a thin board with a thickness of about 2.0 to 2.2 mm, a thickness correction seal 12 with a thickness of 0.1 to 0.5 mm is added on top of the elastic material seal 11.
is attached, and the master mask 13 and copy substrate 14 are vacuum-adsorbed. With the device of this embodiment, it is not possible to increase the utilization rate of recycled substrates by approximately 20%.

FIG. 2 is a schematic cross-sectional view of a portion of a contact printer, which is another embodiment of the mask transfer device according to the present invention, that holds a master mask and a copying substrate in close contact with each other. The figure <a) is the figure <b when using a board with a normal board thickness.
> is the case where a thin board is used, and (c) in the same figure is the case where a thick board is used. I] When using a copy board 24 of normal thickness as in (a), attach a thin thickness correction sticker A26 on top of the sticker 21,
Either vacuum adsorb the master mask 23 and the copy board 24, or if you use a thin copy board 24 as shown in Figure (b), attach a thick thickness correction seal B27 on top of the seal 21. If the plate is thick as shown in Figure (c), only the seal 21 is used. Even with this embodiment, it is not possible to increase the utilization rate of recycled substrates by about 20%.

〔Effect of the invention〕

As explained above, by adopting the photomask transfer device according to the present invention, it is possible to eliminate vacuum leakage when using thin substrates, which was a problem with conventional devices, and to recycle substrates. This makes it possible to increase the utilization rate by approximately 20%.

[Brief explanation of drawings]

FIG. 1(a) is a schematic cross-sectional view showing a part of a contact printer in an embodiment of the present invention, and FIG.
FIG. 2 is a schematic cross-sectional view of another embodiment of the present invention, and FIG. (b) is a schematic cross-sectional diagram when using a thin board, Figure 2 (c) is a schematic cross-sectional diagram when using a thick board, and the third section is a part of a conventional contact printer. A schematic cross-sectional diagram showing the
~(f) is a process section showing the manufacturing process of a mask using a contact printer in a cross-sectional view. 11.21.31...Seal, 12...Plate thickness correction seal, 13,23.33.43...Master mask, 14,24.34...Copy board, 15°35.
... Printing frame, 26... Seal A for plate thickness correction, 27... Seal B for plate thickness correction, 32. Collimation lens, 38... Light source, 39.49.
...Ultraviolet light, 41...Glass substrate, 42...Chromium, 44...Resist.

Claims (1)

[Claims] In a photomask transfer device in which a master mask and a copying substrate to which an image of the master mask is to be transferred are brought into close contact with each other, the copying substrate is vacuum-adsorbed and held via an elastic seal to a printing frame, and the image is transferred by exposure. A photomask transfer device characterized by being equipped with a removable plate thickness correction sticker that corresponds to thickness variations.