JPS6083334A - Washer - Google Patents

Abstract

PURPOSE:To remove abrasives efficiently from the surface of a substrate by washing the substrate while giving a vibration to wash water spirally flowing back by an ultrasonic vibtator fitted to the side surface of a washing tank and removing particles having large specific gravity from a drainage pipe while making fine particles overflow from the washing tank. CONSTITUTION:With a substrate washing tank, a water pipe 2 is fitted to the side surface of a cylindrical washing tank 1 while the bottom of the washing tank 1 takes a funnel shape, a drainage pipe 3 is formed at the center, and an ultrasonic vibrator 4 is fitted to the side surface of the cylindrical washing tank 1, and it is installed to a rest 5 and used. When substrates 6 are entered, water is poured from the water pipe 2 and the substrates are washed while operating the ultrasonic vibrator 4, fine particles in abrasive particles stripped off from the substrates 6 overflow from the upper section of the washing tank 1, and comparatively large particles having specific gravity larger than water are discharged from the drainage pipe 3, thus resulting in complete washing.

Description

[Detailed Description of the Invention] (Al Technical Field of the Invention) The present invention relates to the configuration of a cleaning vinegar tank for cleaning substrates that have been cleaned by the new calendar.' □ (b) Background of the Technology ゛Devices such as semiconductor ICs and LSIs (・1 silicon (S
t), gallium arsenide: (GaAs), etc.
t￥ 1:1 fine patterning of conductor patterns, etc. using thin film formation technology for crystalline substrates and photolithography
A pattern is being created.

In this photo-etching technique, a fine pattern is formed in advance on a semiconductor substrate coated with photoresist, and a photomask is used to project and expose ultraviolet light, il', +-, etc. In the case of using a negative type photoresist, Selective etching is carried out by taking advantage of the property that the light irradiated part becomes insoluble, whereas when using a bossitive, the light irradiated part becomes soluble.

The photomask used in this process is an original plate obtained by depositing chromium (Cr) gold on a substrate made of glass (or even transparent stone) and exposing an original image thereto to form a pattern. It is used as an original plate for projection exposure on semiconductor substrates (wafers) in the mass production process.

Now, the photomask has a high pattern of 81g2,
Because there should be no scratches or contamination, they are replaced with new ones after relatively short use.

Quartz or glass is used as a substrate for photomasks, but if the photomask becomes defective during the photomask production process or becomes defective after use, the mask pattern is removed by etching, and it can be used as a substrate. It is possible to use. The present invention relates to the structure of a cleaning tank used in a substrate recycling process.

fcl Prior Art and Problems Substrates removed as defective during the photomask manufacturing process or substrates that become defective after use can be recycled as long as there are no fatal defects such as deep scratches or substrate cracks. In particular, quartz substrates are more expensive than glass substrates and have superior mechanical properties, so used substrates are often recycled.

That is, Cr is formed to a thickness of about 1000 (A) by immersing it in an etching solution used in forming a photomask, such as a solution consisting of ceric nitrate and perchloric acid.
Remove the layer and then polish Mt! A smooth surface was obtained by polishing (lapping) both surfaces using k and removing several μm of surface FIJ. However, since the abrasives used in this lapping process, such as cerium oxide (CeO), have extremely small particle sizes and are insoluble, it is easy to completely remove these abrasives after lapping is completed. isn't it. However, in order to form a photomask, it is necessary to completely remove these abrasives.

The reason for this is that the thickness of the Cr layer forming the photomask is approximately 10
In addition to being extremely thin (00 (A)), the presence of even a small amount of polishing powder will reduce the adhesive force between the Cr layer and the substrate, resulting in a phenomenon in which the pattern partially fades, resulting in a defect. Conventionally, this has been done by immersing the item in a cleaning tank equipped with an ultrasonic cleaner for a long time, and by sequentially installing such a cleaning tank and moving the item one by one. However, Cε02
The relatively large particles of Shinreki powder were deposited at the bottom of the cleaning tank and were completely suspended in the solution, making it difficult to completely remove Shinreki powder when washing a large amount of substrates continuously.

(cl) Object of the Invention The object of the present invention is to provide a cleaning tank configuration that can efficiently remove abrasive from the surface of a substrate in a short time.

te+ Structure of the Invention The purpose of the present invention is to provide a cylindrical cleaning tank in which a cleaning tank is connected to a water supply pipe that supplies cleaning water, and a cylindrical cleaning tank for cleaning substrates, and a funnel-shaped drain pipe that is connected to the cleaning tank. It consists of
An ultrasonic vibrator installed on the side of the cleaning tank vibrates the swirling cleaning water while cleaning the substrate. Particles with large specific gravity are removed from the drain pipe, while fine particles are washed by overflowing from the cleaning tank. This can be achieved by adopting a structure that

ffl Embodiment of the Invention Fig. 1 is a perspective view of a substrate cleaning tank according to the present invention, Fig. 2 is a perspective view of a substrate holding stand (substrate holder) installed therein, and Fig. 3 (G) is a perspective view of the substrate cleaning tank. The front view and the same figure (B) are a plan view.

The substrate cleaning tank according to the present invention has a structure in which a water supply pipe 2 is provided on the side surface of a cylindrical cleaning tank 1, and an ultrasonic vibrator 4 is provided on the side surface of the cylindrical cleaning tank 1 at the bottom of the cleaning tank 1. Frame 5
It is installed and used. The water supply pipe 2 is shown in Figure 3 (B).
As shown in the figure, the cleaning water is provided in the tangential direction of the cleaning tank 1, and the cleaning water injected through the water supply pipe 2 circulates in the tank in a spiral shape and is discharged from the drain pipe 3.

Further, the ultrasonic vibrator 4 applies ultrasonic vibration to the circulating cleaning water to peel off fine abrasives stuck to the substrate surface from the wafer. Although it is desirable from the viewpoint of not interfering with the reflux of water, it may also be used by hanging it in a washing tank.

Note that a plurality of substrates 6 are arranged at regular intervals using a substrate holder 5 as shown in FIG.

In this case, the substrates 6 used for the photomask are not only rectangular but also disc-shaped with a diameter of 6 or 7 inches, and they are arranged in suitable substrate holders 5 and placed in the cleaning tank 1.
Install it inside.

After inserting the substrate 6 in this way, water is poured from the water supply pipe 2 and the ultrasonic vibrator 4'fr is operated while cleaning, and the internal particles of the abrasive particles peeled off from the substrate 6 are washed away.Ql! Overflow particles from above 11 and relatively large particles having a specific gravity greater than that of water are discharged from the drain pipe 3, allowing complete washing.

In addition, in the washing tank according to the present invention, the diameter of the drain pipe 3 is configured to be smaller than the diameter of the water supply pipe 2.
It is a necessary condition that drainage is carried out by overflow together with drainage from Yosho.

(g) Effects of the Invention The present invention shows that the conventional cleaning tank is not equipped with a drain pipe, and even if it is provided, the drain pipe is located in a bad position, so fine particles with a large specific gravity settle at the bottom of the cleaning tank, and some of them cannot be detected by ultrasonic imaging. However, by using the cleaning tank of the present invention, there is no need to change the cleaning tank many times for cleaning. This can increase cleaning efficiency.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a substrate cleaning tank according to the present invention, Figure 2 is a perspective view of a substrate holding stand, Figure 3 is a front view of the substrate cleaning tank, and (B) is a plan view. 1 is a substrate cleaning tank, 2 is a water supply pipe, 3 is a drain pipe,
4 is an ultrasonic transducer, 5 is a pedestal, and 6 is a substrate.

Claims (2)

[Claims] (1) A water supply pipe that supplies cleaning water to a device for cleaning the substrate, and a cylindrical cleaning pipe Il′I to which the water supply pipe is connected;
A funnel-shaped drain pipe is connected to the washing tank, and the water supply pipe is tapered tangentially to the washing tank, and the water supplied from the water supply pipe flows inside the washing tank in a spiral shape. A washing device characterized in that water is discharged from a drain pipe by circulating water. (2) The washing device according to claim 1, characterized in that an ultrasonic vibrator is provided on the side surface of the outer circumference of the washing tank, and washing is performed by applying ultrasonic vibrations to the washing water without interfering with circulation. :...