JPS59168446A - Washing method - Google Patents

Abstract

PURPOSE:To prevent generation of static electricity and to wash a wafer or mask and a reticle with good reproducibility at a high degree of washing by bubbling gaseous CO2 in a cascade tank contg. the wafer or mask and reticle and spraying the pure water bubbled with gaseous CO2 like a shower thereto. CONSTITUTION:Gaseous CO2 is bubbled in a cascade tank in which a wafer or mask and reticle are stored. The wafer or mask and reticle 4 are supported on a supporting plate 5. Gaseous CO2 is bubbled in pure water supplied through a piping 7 connected to a piping 6 for the pure water. Such pure water is sprayed, like a shower, from a nozzle provided perpendicularly to the plate 5 to the wafer or mask and reticle 4, by which the wafer or mask and reticle are washed. The chip-off of Cr and the adsorption of dust are thus prevented and a gate short circuit or the like owing to static electricity is prevented in the stage of washing the wafer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in the process of cleaning a mask or reticle used when exposing a sea urchin/S- and the process of cleaning a wafer in a photoresist process.

Traditionally, mask and reticle cleaning processes are common (second order).

■Washing → ■Shower washing → ■Drying → ■Scrubbing with detergent (non-ionic) →■Shower washing → ■Drying.

For cleaning in (3), there is a method of soaking sea urchins in 1M machine stripping agent to remove the photoresist that adheres when exposing them.
There is an acid cleaning method that uses sulfuric acid and nitric acid. ■Washing is
This is the process of scrubbing away foreign matter that could not be removed by washing with a detergent-soaked sponge. In recent years (=
As the degree of integration of semiconductor devices increases and the miniaturization of semiconductor elements, reduced projection type alignment exposure machines are used instead of contact type alignment exposure machines, and opportunities for cleaning reticles also increase. Although it is increasing, the reticle is a sea urchin...
Since it is unlikely that the product will come into contact with other objects, the washing step (■) is often omitted. On the other hand, washing with ■ and washing with water,
This is a process of washing away dust and the like that was removed from organic stripping agents, inorganic stripping agents such as acids, detergents, masks, etc. used in washing (1) and (2).

Usually, this is done by showering pure water onto the mask or reticle, but of course, the higher the flow rate of pure water and the higher the pressure of the shower, the greater the ability to wash it off. However, the static electricity generated when pure water hits the chrome surface of the mask or reticle also increases, and for this reason, the mask,
The drawback was that the chrome on the reticle was missing.

Furthermore, this static electricity causes problems such as ionized dust and the like being attracted to the mask and reticle surfaces. The same goes for wafers; washing them with water generates static electricity, which causes gate shorts.

The present invention eliminates the drawbacks of the conventional wafer or mask and reticle cleaning methods described above and provides a cleaning method with extremely high reproducibility and extremely high degree of cleaning.

The present invention is characterized in that carbon dioxide gas is bubbled into the wafer or mask and reticle in a cascade bath, and the wafer or mask and reticle are washed away with a shower-like pure water in which carbon dioxide gas is bubbled.

According to the present invention, when the mask and reticle are washed in the shower, carbon dioxide gas is bubbled into the pure water to prevent static electricity generated on the mask and reticle, thereby preventing chromium missing and dust adsorption. It can be prevented. Regarding wafers, it is possible to prevent gate short circuits, and this also increases the flow rate of pure water and the shower pressure, thereby increasing the cleaning performance of the shower.

Next, a conventional method and a method according to the present invention will be described with reference to the drawings regarding the shower washing step in the mask and reticle washing step.

FIG. 1 is a diagram showing a shower flushing method using only pure water C2 as an example of a conventional shower flushing method. In FIG. 1, a mask or reticle 1 is supported by a support plate 2, and purified water is blown out from a shower nozzle 3 provided perpendicularly to the support plate.

The mask or reticle is washed with water. This method creates static electricity on the mask or reticle, resulting in various drawbacks.

On the other hand, two embodiments of the shower flushing method of the present invention will be described.

In FIGS. 2 and 2, the mask or reticle 4 is attached to the support plate 5.
Supported by A pipe 7 for flowing carbon dioxide gas is connected to the pure water pipe 6, carbon dioxide gas is bubbled in the pure water, and the pure water is sprayed onto the mask or reticle in a shower-like manner from a nozzle installed vertically on the support plate. Put on. According to this method, shower washing can be performed without generating static electricity on the mask or reticle.

As described above, according to the present invention, it is possible to increase the flow rate of pure water and the shower pressure, so that the cleaning ability can be increased and, moreover, the loss of chromium can be prevented. The same applies to washing the wafer with water, and gate short circuits due to static electricity can be prevented. Furthermore, bubbling the C2 carbon dioxide gas in the cascade tank in which wafers, masks, and reticles are stored has an additional effect of preventing static electricity.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a conventional shower flushing method, and FIG. 2 is a diagram showing an embodiment according to the present invention. In addition, in the figure, 1, 4... Mask or reticle, 2.5... Support plate, 3... Nozzle, 6... Piping for pure water. , 7... Piping for carbon dioxide gas.

Claims (1)

[Claims] j during the cleaning process of wafers, masks, reticles, etc.
In the water washing process, carbon dioxide gas is bubbled in a cascade cleaner, and the cleaning method is characterized by sprinkling pure water with bubbled carbon dioxide gas in a shower-like manner.