JPH05228413A - Coating device - Google Patents

Abstract

PURPOSE:To provide a coating device constituted so that the residue of a liquid composition such as a resist is hard to adhere to the tip part of a nozzle. CONSTITUTION:In a coating device wherein a liquid compsn. (e.g. resist) 2 being a membrane material is dropped from the nozzle 1 arranged above a substrate and applied to the surface of the substrate in a membrane form, the nozzle wall at the tip part of the dripping orifice of the nozzle 1 is processed so as to become thin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for applying a thin film of photoresist onto the surface of a substrate such as a wafer for manufacturing integrated circuits.

[0002]

2. Description of the Related Art Conventionally, as a photoresist coating apparatus, an apparatus based on a spin coating method is most widely used. The spin coat type coating device is composed of a wafer rotating part, a solution tank, an extraction nozzle part, and a dispenser part, and each part is devised so that a uniform film can be applied without contamination of foreign matter.

For example, in the extraction nozzle section, research has been conducted on optimization of the resist nozzle shape and solution dropping amount, use of a solution filter, shortening of the distance between the resist nozzle (hereinafter referred to simply as nozzle) and the wafer. There is.

In the resist coating apparatus which has been often used heretofore, the tip shape of the nozzle 3 is changed as shown in FIG. 4 in order to prevent the resist from dropping and prevent the resist from drying at the nozzle tip. It became thinner toward the tip, and a suck back mechanism was provided on the main body of the device.

[0005]

In manufacturing a nozzle as shown in FIG. 4, a Teflon (trade name) tube having an outer diameter of 8 mm and an inner diameter of 6 mm is usually heated to form a tapered tip. Shape it. Next, since the optimum inner diameter of the nozzle is determined from the relationship between the viscosity of the resist and the dropping amount, the tip of the nozzle is cut off at the position where the inner diameter is obtained. In this case, the thickness d of the nozzle wall at the tip of the dropping port of the nozzle
Was about 0.2 to 0.3 mm.

FIG. 5 shows the state of the nozzle during the resist coating operation. In FIG. 5, (a) shows a state before dropping the resist 2, (b) shows a state during dropping, and (c) shows a state where suck back is completed after dropping.

As shown in FIG. 5C, the resist 4 adheres to the tip portion of the nozzle 3 and remains as it is immediately after the suck back is performed. As described above, since the thickness of the nozzle wall at the tip of the nozzle 3 is 0.2 to 0.3 mm, if the resist 4 attached here dries and drops onto the thin film surface below the nozzle 3. As a result, they become foreign matter (particles), which causes a problem in the subsequent process. This problem can become a serious problem as the miniaturization of integrated circuits progresses.

The present invention has been made in view of the above conventional problems, and an object of the present invention is to provide a coating apparatus which does not have a problem associated with the generation of particles in the nozzle portion.

[0009]

In view of the above-mentioned problems, the coating apparatus according to the present invention drops a liquid composition, which is a thin film material, from a nozzle arranged above a substrate, and deposits the liquid on the surface of the substrate. In a coating device that coats in a thin film, the problem is achieved by using a nozzle in which the nozzle wall is thinly processed at the tip of the dropping port of the nozzle.

[0010]

When the tip of the nozzle 3 is viewed from the substrate side below the nozzle 3, the conventional one is a donut-shaped disc as shown in FIG. 4 (b). In the present invention, in order to suppress the generation of particles as described above, the annular area of the nozzle tip surface is made as small as possible, and the vertical cross-sectional shape is made into a knife edge shape so that a resist residue is generated at the nozzle tip. I made it so that it would not be a problem. In order to reduce the annular area of the tip surface, specifically, the tip of the nozzle may be polished to make the tube wall as thin as possible.

As described above, since Teflon is usually used as the material of the nozzle, in this case, it is cooled with liquid nitrogen or the like and is polished with a lathe or the like while being kept at a low temperature.

Here, in the coating apparatus according to the present invention,
The state of the nozzle during the coating operation is shown in FIG. In FIG. 2, (a) shows a state before the resist 2 is dropped, (b) shows a dropping state, and (c) shows a state where suck back is completed after the dropping.

In the present invention, as shown in FIGS. 2A to 2C, when the resist 2 is returned to the nozzle 1 by the suck back mechanism after the resist is discharged, the resist 2 remains at the tip of the nozzle 1. Due to the difficult structure, it is possible to prevent problems due to particles.

[0014]

EXAMPLE FIG. 3 is a schematic view showing an example of a coating apparatus according to the present invention. In the figure, a wafer chuck 105 is a spinner shaft 111 driven by a spin motor 103.
have. A wafer (not shown) to which the resist 110 is applied is placed on the wafer chuck 105. Receiving scattered resist around the wafer chuck 105,
A spin cup 104 for preventing splashing is installed.
A resist nozzle 101 for dropping the resist 110 is arranged above the wafer chuck 105 substantially in the center thereof.

The resist 110 is a resist tank 109.
It is stored inside and is pushed out to the resist nozzle 101 by the pump 107. A filter 108 is provided between the pump 107 and the resist nozzle 101, and if foreign matter is contained in the resist 110, it is removed here.

Further, the pump 107 and the resist nozzle 1
Between 01 and 01, a suck back mechanism 106 is provided to prevent the resist from dropping. Reference numeral 102 denotes a mechanism for moving the resist nozzle, which can move the resist nozzle 101 vertically and horizontally.

As shown in FIG. 1, the resist nozzle 101 is processed so that the thickness of the tube wall at the tip is as thin as possible. In manufacturing such a resist nozzle 101, first, a conventional Teflon (trade name) tube having an outer diameter of 8 mm and an inner diameter of 6 mm is heated into a tapered shape to obtain an appropriate nozzle inner diameter. At the position where it will be cut off the tip of the tube. Then, while cooling with liquid nitrogen etc. and maintaining at a low temperature, polishing with a lathe etc.
Processing is performed until the thickness becomes about 5 μm (needless to say, thinner is better). This thickness is determined by the degree of fineness of the circuit.

The operation of coating the resist 110 on the wafer surface using the coating apparatus having the above structure will be described below.

First, the resist nozzle moving mechanism 102 moves the resist nozzle 101 to a position other than on the wafer chuck 105 to perform dummy dispensing. This is a process of throwing away the resist 110 whose viscosity has changed due to long contact with the air at the tip of the resist nozzle 101.

Next, the wafer is placed on the wafer chuck 105 such that the center of rotation of the wafer chuck 105 and the center of the wafer coincide with each other. After that, the resist nozzle 101 is moved onto the wafer by the resist nozzle moving mechanism 102, and a predetermined amount of the resist 110 is applied to the substantially central portion of the wafer surface.
Is dropped. 2 (a) to 2 (c) show the state of dropping the resist 110 with time.

FIG. 2A shows a state before dropping, FIG. 2B shows a state during dropping, and FIG. 2C shows a state in which suck back is completed after dropping. In the diagram (c), since the tip of the resist nozzle 101 is thinly processed as described above, an amount of resist that would cause a problem in a later step does not adhere.

After the dropping, the wafer fixed to the wafer chuck 105 is rotated at a low speed of, for example, about 500 rpm for 2 seconds to spread the resist 110 on the entire surface of the wafer. further,
For example, by rotating the wafer for 20 seconds at a high speed of 4000 rpm, the resist 110 has a uniform film thickness.
The removal of the wafer is performed by moving the resist nozzle 101.

The coating process for one wafer is completed as described above.

Here, the case where the present invention is applied to a photoresist coating apparatus has been described. However, the thin film forming method by spin coating used in this apparatus is inexpensive and highly reproducible. for that reason,
2. Description of the Related Art A spin coater, which is a partially improved version of a photoresist coater, has been widely used in the manufacture of semiconductor devices. For example, it is used when a solution of organic silicon and an impurity compound dissolved in alcohol is applied and dried to form an inorganic coating, or an organic coating such as polyimide is formed. Even in such a case, the generation of particles is a problem that should be prevented as in the case of resist coating, and it is effective to apply the present invention.

[0025]

As described above, according to the present invention, there is an effect that the amount of resist attached to the tip of the nozzle becomes extremely small and the generation of particles due to the nozzle portion is suppressed.

[Brief description of drawings]

FIG. 1 is a sectional view of a resist nozzle of a coating apparatus according to an embodiment of the present invention.

2A is a cross-sectional view before resist dropping, FIG. 2B is a cross-sectional view during resist dropping, and FIG. 2C is a cross-sectional view in a state where suck back is completed after resist dropping.

FIG. 3 is a conceptual diagram of an embodiment of a coating apparatus according to the present invention.

FIG. 4 is a cross-sectional view of a resist nozzle of a conventional coating device.

5A is a cross-sectional view of a conventional coating apparatus before resist dropping, FIG. 5B is a cross-sectional view during resist dropping, and FIG. 5C is a cross-sectional view of a state in which suck back is completed after resist dropping.

[Explanation of symbols]

 1 resist nozzle 2 resist 3 conventional resist nozzle 4 resist residue 101 resist nozzle according to the present invention 102 resist nozzle moving mechanism 103 spin motor 104 spin cup 105 wafer chuck 106 suck back 107 pump 108 filter 109 resist tank 110 resist

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location H01L 21/027

Claims (1)

[Claims] 1. A coating apparatus for dropping a liquid composition, which is a thin film material, from a nozzle arranged above a substrate, and applying the liquid composition in a thin film form on the surface of the substrate, a tip of a dropping port of the nozzle. The coating device has a nozzle wall whose nozzle wall is thinly processed into a knife edge shape.