JPS5910364A - Rotary coating device - Google Patents

Abstract

PURPOSE:To enable uniform and clean dropping, by controlling the treatment liquid which drops by gravity from a vessel by means of a valve. CONSTITUTION:A vessel 21 is made directly connectable to the inlet of a valve 22, and has the construction to enable the simple attaching and detaching to and from the valve 22. The vessel 21 is formed to a tray shape having a large bottom area in order to decrease the change in the dropping pressure that arises with a change in the level of treatment liquid 20. Said vessel is manufactured of a hydrophobic material in order to prevent sticking and solidifying of the liquid 20 on the inside wall thereof. The valve 22 blocks the treatment liquid trying to flow out from the vessel 21 and prevents the leakage of the treatment liquid from a nozzle 23. The opening and closing of the valve 22 are controlled by an electric signal, pneumatic pressure or the like, and the flows of the control liquid is controlled by the closing or opening time. A nozzle 24 is made of a hydrophobic material like the vessel 21, and the inside diameter d1 in the forward end part thereof is made small to increase the wall thickness so that liquid drops do not spread on the outside wall surface of the nozzle.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spin coating apparatus having a processing liquid dropping device for manufacturing semiconductors, particularly for spin coating processing liquids such as impurity diffusing agents and protective film forming agents, and has two pages.

2. Description of the Related Art FIG. 1 shows a conventional example of an apparatus for spin-coating a processing liquid such as a silica film used as an impurity diffusing agent in the manufacture of semiconductors. As shown in FIG. 1, in the conventional method, a treatment liquid 1 is sucked in by a pump 3 from a container 2 containing the treatment liquid, passed through a valve 4, forced out from a nozzle 5, and dripped onto an object to be coated 6a. The coating material 6a is mounted on a rotating device 6b, and the dropped treatment liquid is applied by rotation. The processing liquid path from the container 1 to the nozzle 5 is connected by a pipe 7.

In the conventional apparatus, a large amount of processing liquid remains in the pump 3, valve 4, and pipe 7 shown in FIG. Therefore, processing liquid 1
If the liquid is unstable at room temperature and must be applied fresh, the pump 3 and valve 4 mentioned above should be replaced each time the device is used.
However, there is a drawback that the pipe 7 must be cleaned using an organic solvent and the organic solvent must be replaced with a new treatment liquid before using the apparatus. Furthermore, when it is desired to change the type of processing liquid 1, it is necessary to similarly clean the entire apparatus, and there is a disadvantage that a large amount of processing liquid is used for cleaning and replacement.

Further, in the conventional apparatus, the processing liquid may leak out from the nozzle 6 depending on the extrusion from the pump 3 or the shape of the nozzle 6. In order to prevent leakage of the processing liquid, pumps 3 and 7 are equipped with a suction mechanism that sucks a small amount of the processing liquid immediately after dropping the processing liquid.
It is provided in r4.

Fig. 2 1d, -, 1 Nozzle 5 when there is no suction mechanism
FIG. 3 is a cross-sectional view of the nozzle portion showing how the processing liquid leaks from the nozzle. The processing liquid 1 does not remain in the nozzle 5 but leaks to the tip 8 of the nozzle or falls as droplets 9 of the processing liquid.

FIG. 3 is a sectional view of the nozzle portion of the conventional device when the above-mentioned suction mechanism can be seen. The above-mentioned suction mechanism sucks the processing liquid 1 into the nozzle δ immediately after dropping, and at the same time creates bubbles 10 in the nozzle 6.

Due to the presence of air bubbles 10, when the processing liquid is dropped, the processing liquid is scattered in the form of a mist and is not uniformly dropped on the coated surface, resulting in local disturbance of the processing liquid film after spin coating. arise. Further, if the shape of the nozzle is sharp at the tip as shown in FIG. 3, the processing liquid wraps around the outer wall of the nozzle tip. When the processing liquid uses an organic solvent as a solvent, the solvent evaporates in the air, the processing liquid solidifies, and a coagulated product 11 of the processing liquid adheres at the tip of the nozzle. The coagulated material falls onto the coating surface together with the processing liquid, causing extensive disturbances on the coating surface.

FIG. 4 shows how the treatment liquid is dropped onto the coating material 6a when the bubbles 1o are formed. A coating film 12 is formed on the coated material in very localized areas.

FIG. 5 shows the state of the coated surface after spin coating of the coagulated material 11. FIG. 5M shows a top view, and FIG. 5B shows a sectional view. After dropping the treatment liquid, the coated material is rotated at high speed so that the coating film created by the dropping spreads uniformly over the coated surface to form a very thin film 13, but due to the presence of the coagulated material 11, the coated material is rotated radially after the spin coating. Membrane disturbance 1
There is a drawback that 4 occurs.

The present invention eliminates the above-mentioned drawbacks of the conventional method of dropping a processing liquid in spin coating, and removes the processing liquid from the nozzle by taking into account the shape and material of the nozzle (page 5). This allows for uniform and clean dripping by utilizing natural fall, and also makes it easier to clean the device.

The processing liquid dropping device of the present invention has a structure in which the processing liquid that naturally falls from a container is controlled by a valve and drips from a nozzle. The shape of the nozzle is determined by the viscosity of the processing liquid and the tension on the nozzle's nose to prevent the processing liquid from leaking.The nozzle tip is made narrower and thicker to prevent the processing liquid from leaking at the nozzle tip. It has a structure that prevents it from disintegrating with air. The structure has a rotating device directly below the nozzle.

A spin coating apparatus according to an embodiment of the present invention will be explained with reference to FIG. In FIG. 6, 21 is a container for storing the processing liquid;
2 is a valve, and 23 is a nozzle.

The container 21 has a bottom surface that can be directly connected to the inlet of the valve 22, and has a structure that can be easily attached to and removed from the valve 22. container 2
1 has a dish-shaped structure with a large bottom area in order to suppress changes in the lower pressure caused by changes in the liquid level of the processing liquid 2o. Further, it is preferable to use a hydrophobic material for the container 21 in order to prevent the processing liquid from adhering to the inner wall and solidifying.

The valve 22 serves to stop the processing liquid from flowing out from the container 21 and to stop the processing liquid from leaking out from the nozzle 23. The opening and closing of the valve 22 is controlled by electrical signals, air pressure, etc., and the amount of liquid dripped is controlled by the opening and closing time.

Like the container 21, the nozzle 23 is made of a hydrophobic material such as Teflon or polyester in order to prevent the processing liquid from adhering to the nozzle 23. The nozzle 23 has an inner diameter d1 at its tip smaller than an inner diameter d2 at the connecting portion between the nozzle 23 and the valve 22. In order to prevent the processing liquid from flowing down a part of the inner wall surface of the nozzle 23 and becoming turbulent and scattering from the tip of the nozzle 23, the inner diameter is made small at the tip of the nozzle 23 so that the processing liquid flows through the nozzle. It is a structure that creates a state of fulfillment inside. The inner diameter d1 of the tip of the nozzle 23 is selected to a size that allows the treatment liquid to drip without scattering so that the treatment liquid does not leak out when the valve 22 is closed. If the tip of the nozzle (page 7, page 23) is sharp and the wall thickness is thin, or if the material is made of a metal with weak hydrophobicity, the processing liquid will wrap around the outer wall surface of the nozzle tip, solidify and adhere, and the processing liquid will drop when dripping. It also falls onto the coated surface. To prevent this, the thickness of the tip of the nozzle 23 can be increased to prevent the droplets of the processing liquid from spreading on the outer wall surface of the nozzle.

As shown in FIG. 6, the distance 7!3 between the nozzle 23 and the semiconductor material 26 is set so that the processing liquid does not scatter.

The processing liquid dripped from the nozzle 23 is dropped onto the semiconductor material 25 mounted on the rotating table 24, and the rotating table is rotated at high speed to apply the processing liquid onto the semiconductor material.

As described above, the structure of the apparatus shown in FIG. 6 makes it possible to prevent the processing liquid from leaking, to prevent the processing liquid from scattering, and to prevent the coagulation of the processing liquid from adhering to the nozzle. In this apparatus, the container 21, valve 22, and nozzle 23 can be easily removed and replaced with the processing liquid. It is also easy to create a nozzle to match the viscosity and properties of the treatment liquid.
The nozzle can also be replaced depending on the type of processing liquid.

For example, in the process of diffusing MuS onto a silicon substrate using the present invention, an impurity diffusion agent containing 5.9% of a silicon compound as a main component and 0.5% of arsenic as an impurity using ethyl alcohol as a processing liquid as a solvent. When the above-mentioned treatment liquid was dropped onto a silicon substrate and spin coating was carried out using a , the treatment liquid could be coated without leakage or adhesion of coagulum, and without scattering.

In the case of the above treatment liquid, the shape of the nozzle 23 in FIG. 6 has an inner diameter d1 of 3111 m and an inner diameter d2 of 4 rrr! n,
The wall thickness of the tip of the nozzle is 3111111, the material is deflon, the length of the nozzle 23 is 7!1 is 50, the total length of the device is /! 2 in the order of 200, the length 713 from the nozzle 23 to the coating surface 1 is 1511111, and by opening the valve 22 for about 0.2 seconds, about 0.5 cc of processing liquid can be dripped. The coating film 26 formed by dropping the above treatment liquid onto a silicon substrate 26 with a diameter of 75111 m and spinning coating at 4000 r, p, Hl for 2.0 seconds has approximately 100% of foreign matter on the coated surface compared to the conventional method. 5, and the disturbance on the coated surface as shown in FIG. 5 disappeared.

As shown on page 9 and above, if the spin coating device k equipped with the processing liquid dripping device according to the present invention is used once a month, spin coating will be possible without causing any disturbance to the coating film, and it will be possible to replace the processing liquid and operate the device. Wash a
1 has become easier. This has resulted in step-by-step improvements in semiconductor manufacturing and improved efficiency.

[Brief explanation of drawings]

Figure 1 is a schematic configuration diagram of a conventional spin coating device, Figure 2 is
3 and 4 are structural cross-sectional views of the nozzle portion of a conventional processing liquid dripping device and diagrams showing the dripping state, and FIG. 6(A),
(B) is a plan view of the coated surface after spin coating when a conventional treatment liquid dropping device is used, and a sectional view of the coated substrate, and FIG. 6 is a structural sectional view of the spin coating device according to an embodiment of the present invention. It is. 20... Processing liquid, 21... Container, 22
...Valve, 23...Nozzle, 24...
...Rotating table, 26...Semiconductor material, 26...
...Coating film. Name of agent: Patent attorney Toshio Nakao and one other person
IFgJ Figure 4 4b /6 also Figure 5 (/'l)
(B) Sixth
figure

Claims (3)

[Claims] (1) A valve is provided between a container that holds a processing liquid for semiconductor manufacturing and a nozzle that drips the processing liquid, and the amount of the processing liquid that naturally falls from the container through the nozzle is controlled by the valve. A rotary coating device with a treatment liquid dripping structure. (2) The spin coating device according to claim 1, wherein the container, valve, and nozzle are removable. (3) The spin coating device according to claim 1, wherein the inner diameter of the nozzle is narrow at the tip of the nozzle, and the thickness of the tip of the nozzle is thicker than that of other parts.