JPH04145617A - Application device - Google Patents

Abstract

PURPOSE:To control a film thickness of application accurately by providing a temperature adjustment mechanism inside a chamber wall of a rotating application device. CONSTITUTION:An upper cover 1a rises against an outer cup 1b to form a space for containing a wafer 3. The wafer 3 is supplied above a spin chuck in a chamber 1 to close the space. An interior of the chamber is made air tight and a specified amount of resist solution is dropped from a nozzle 5. Uniform application is carried out all over through rotation. A circulating thermostat 10 circulates water of a specified temperature to a flow path 11 of a temperature adjustment medium to control an atmosphere in the chamber 1 to a specified temperature, and a chuck 4 and the wafer 3 are kept at a specified temperature by a temperature adjustment mechanism which is not shown in the figure. According to this constitution, it is possible to realize application through slow rotation and to enable resist application which is proper for a wafer of a large diameter or a stepped wafer. Solvent S, for example is introduced from a liquid introduction tube 2 to a trap 1d as required to control an atmosphere of solvent in the chamber 1. A resist film thickness can be controlled accurately in this way.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a coating device.

(Prior art) Conventionally, in the manufacturing process of semiconductor devices, circuit patterns have been transferred by applying a coating liquid to the surface of a semiconductor wafer, etc., by forming a resist film, for example, and using precision photo transfer technology. A resist coating device is used to form such a resist film.

Resist coating equipment that forms resist films on semiconductor wafers uses a so-called spin coater, which supplies resist solution to the semiconductor wafer and then rotates the semiconductor wafer at high speed to uniformly apply the resist solution over the entire surface of the semiconductor wafer using centrifugal force. be.

Incidentally, in recent years, semiconductor devices have tended to become highly integrated, and with this trend, the circuit patterns of semiconductor devices have tended to become increasingly finer. In order to transfer accurately, it is required to accurately control the resist film thickness. For this reason, resist coating equipment has traditionally
Efforts have been made to improve the accuracy of the absolute film thickness of the resist film and the in-plane uniformity of the film thickness by adjusting the resist temperature, adjusting the semiconductor wafer temperature, adjusting the rotation speed, and introducing temperature-controlled gas. There is.

In addition, conventionally, resist coating was performed in an open atmosphere, but a coating apparatus has been proposed in which a semiconductor wafer is housed in an airtight chamber and resist coating is performed in a predetermined solvent scum atmosphere within the chamber. There is. With a coating device that performs resist application under such an airtight atmosphere, it is possible to perform resist application at a lower rotation speed than when resist application is performed under an open atmosphere. It has the characteristic that it can be done.

(Problem to be Solved by the Invention) However, when resist coating is performed in an airtight atmosphere, the temperature of the solvent in the atmosphere changes depending on the temperature of the chamber.
There was a problem in that the film thickness varied. .

The present invention has been made in response to such conventional circumstances, and it is an object of the present invention to provide a coating device that can control the coating film thickness more accurately than in the prior art.

[Structure of the Invention] (Means for Solving the Problems) That is, the present invention supplies a coating liquid to a substrate to be processed, rotates the substrate to be processed, and spreads the coating liquid on the surface of the substrate to be processed in the form of a film. The present invention is characterized in that the coating apparatus includes a chamber for accommodating the substrate to be processed, and a temperature adjustment mechanism provided in the wall of the chamber for adjusting the temperature.

(Function) Upon detailed investigation by the present inventors, we found that in conventional resist coating equipment, in addition to the resist temperature, semiconductor wafer temperature, rotation speed, etc. described above, fluctuations in ambient temperature have a large effect on resist film thickness. It turned out that it was. In other words, resist coating equipment is usually placed in a temperature-controlled clean room with a downflow system.
There are slight temperature fluctuations in this clean room as well.
It was found that this temperature fluctuation had a large effect on the resist film thickness.

Therefore, in the coating apparatus of the present invention, by providing a chamber that accommodates the substrate to be processed and a temperature adjustment mechanism that adjusts the temperature inside this chamber, the atmospheric temperature around the substrate to be processed can be accurately adjusted, compared to the conventional method. This makes it possible to precisely control the coating film thickness.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the resist coating apparatus is provided with a chamber 1 formed of, for example, aluminum or stainless steel in a cylindrical shape and configured to be able to maintain an airtight interior. This chamber 1 is composed of an upper cover 1a, an outer cup 1b, and an inner cup 1c, which are configured to be relatively movable up and down by a lifting mechanism (not shown).

The state shown in FIG. 1 shows a state in which these are brought into contact with each other to keep the inside airtight, and a resist liquid coating process is performed. In this state, a liquid reservoir 1d capable of storing a desired liquid is formed between the outer cup 1b and the inner cup IC, and a desired liquid, such as a solvent S, is introduced from the liquid introduction pipe 2 connected to the outer cup 1b. It is configured so that it can be introduced into the liquid reservoir 1d.

Note that from this state, the upper cover 1 is removed from the outer cup 1b.
If you move these relatively up and down so that a rises,
A gap is formed between these for loading and unloading the semiconductor wafer 3.

Further, when the inner cup 1c is moved vertically relative to the outer cup 1b so as to be lowered, the solvent S in the liquid reservoir 1d flows down into the inner cup lc, and is led out from there by a drain pipe (not shown). It is configured to be discharged outside the chamber 1.

A spin chunk 4 is provided in the chamber 1 and is configured to hold a semiconductor wafer 3 by suction using, for example, a vacuum chuck and rotate at high speed. Further, a resist supply nozzle 5 connected to a resist storage container (not shown) is provided above the center of the spin chuck 4.
For example, the resist solution in the resist storage container is fed by gas pressure such as high-pressure nitrogen, and is supplied from the resist supply nozzle 5 to the semiconductor wafer 3 held on the spin chuck 4 . Furthermore, spin chuck 4 and chamber 1
(inner cup lc), for example, a bellows mechanism 6 is provided as a mechanism for airtightly closing the space between them and further enabling vertical movement of the spin chuck.

Moreover, above the spin chuck 4 in the chamber 1,
An airflow adjusting plate 7 is provided for adjusting the airflow within the chamber 1 caused by the rotation of the semiconductor wafer 3 and improving the in-plane uniformity of the resist film thickness. This airflow adjustment plate 7
is made of, for example, aluminum or stainless steel, and has a triangular shape, for example.

In the case of this embodiment, the inner diameter of the chamber 1 (indicated by the reference symbol in the figure) is approximately 160n+a+ so that the resist can be applied to the semiconductor wafer 3 having a diameter of 6 inches. The height to the end (indicated by the symbol H in the figure) is set to approximately 80IIffl. For this reason, the shape and dimensions of the airflow adjustment plate 7 are set in accordance with the shape and dimensions of the chamber 1. As shown in FIG. 2, the airflow adjusting plates 7 include a plurality of, for example, four triangular plates arranged so as to be perpendicular to the airflow.

In this embodiment, four triangular airflow regulating plates 7 are installed in the chamber 1 so as to be almost perpendicular to the surface of the semiconductor unit 3 (the shape, size, and shape of the airflow regulating plates 7,
The number of sheets, placement position, placement angle, etc. can be changed, and
The state of film formation changes depending on the combination of coating conditions, such as the number of rotations of the semiconductor wafer 3, the rotation time, the type of resist solution, etc. By selecting these optimally, the resist film thickness can be improved. Internal uniformity can be improved.

Furthermore, the chamber 1 is provided with a temperature adjustment mechanism. This temperature control mechanism includes, for example, a circulation constant temperature bath 1 that circulates a temperature control medium, such as water, controlled to a predetermined temperature.
0, and a temperature regulating medium flow path 11 provided in each part of the chamber 1, for example, the outer cup 1b. The circulation constant temperature bath 10 includes a temperature control medium flow path 1 of the chamber 1.
It is configured to perform temperature control using a temperature detection signal from a temperature sensor 12 provided in the temperature sensor 1 as a reference signal.

Note that the temperature regulating medium flow path 11 may be provided in other than the outer cup 1b, for example, in the upper cover 1a, the inner cup IC, etc.
A plurality of them may be provided. The spin chuck 4 is also provided with a temperature control mechanism (not shown) that keeps the semiconductor Unino X3 at a predetermined temperature while preventing the heat of the driving motor from being transmitted to the semiconductor wafer 3, and also controls the resist liquid supply system. , a temperature adjustment mechanism (not shown) is provided for adjusting the temperature of the resist solution.

In the resist coating apparatus of this embodiment having the above configuration, as described above, the upper cover 1a is moved up and down relative to the outer cup 1b from the state shown in FIG. A gap is formed for loading and unloading the semiconductor wafer 3. From here, the semiconductor wafer 3 is loaded onto the spin chuck 4 in the chamber 1 using an automatic transfer device or the like. In addition, semiconductor sea urchin l\3
is preferably set to a predetermined temperature in advance.

Next, the gap is closed to make the inside of the chamber 1 airtight, and a predetermined amount of resist liquid is dropped from the resist supply nozzle 5 onto the substantially central portion of the semiconductor wafer 3. Thereafter, the semiconductor wafer 3 is rotated by the spin chuck 4 at a predetermined rotation speed for a predetermined time, for example, at a rotation speed of 2000 rpm for 30 seconds, and the resist solution is uniformly applied to almost the entire surface of the semiconductor sea urchin tX3 by centrifugal force.

At this time, the temperature control medium flow path 11
The atmospheric temperature within the chamber 1 is controlled to a predetermined temperature by circulating water at a predetermined temperature inside the chamber. Further, a temperature control mechanism (not shown) of the spin chuck 4 controls the temperature of the semiconductor wafer 3 to a predetermined temperature, and a temperature control mechanism (not shown) of the resist liquid supply system controls the temperature of the semiconductor wafer 3 to be supplied to the semiconductor wafer/X3. The temperature of the resist solution used is controlled to a predetermined temperature.

As described above, in the resist coating apparatus of this embodiment, resist coating is performed in an airtight atmosphere within the chamber 1, so that coating can be performed at a lower rotation speed than in the case of coating in an open atmosphere. For example, it is suitable for applying photoresist to large-diameter wafers, uneven surfaces, etc.

Particularly when applied to a stepped surface, it has the characteristic of being able to be applied symmetrically. At this time, the solvent atmosphere in the chamber 1 may be controlled by reducing the pressure in the chamber 1 or introducing a desired liquid, such as the solvent S, from the liquid introduction pipe 2 into the liquid reservoir 1d, if necessary.

Here, FIG. 3 shows two examples of the results of investigating the relationship between the temperature inside the chamber 1 and the absolute film thickness of a resist film formed on a semiconductor wafer. As shown in this graph, when the temperature changes by 1° C. at room temperature, the absolute film thickness changes by about 100 angstroms. However, in general, the temperature inside a clean room may change by about 1°C. For this reason, in conventional resist coating apparatuses, the film thickness changes due to such temperature changes. It is also conceivable that the temperature of the wall surface of the outer cup 16 decreases due to evaporation of the resist solvent attached to the chamber, especially the outer cup 16.

On the other hand, in the resist coating apparatus of this embodiment, in addition to controlling the temperature of the semiconductor wafer 3 by the temperature control mechanism of the spin chuck 4 and controlling the temperature of the resist solution by the temperature control mechanism of the resist solution supply system, the temperature control mechanism of the resist solution supply system controls the temperature of the resist solution. Since the ambient temperature is controlled to a predetermined temperature, the accuracy and in-plane uniformity of the absolute film thickness of the resist film can be improved, and the resist film thickness can be controlled more accurately than in the past.

[Effects of the Invention] As explained above, according to the resist coating apparatus of the present invention, the accuracy of the absolute film thickness of the resist film and the in-plane uniformity of the film thickness can be improved, and the resist film can be coated more easily than before. Thickness can be precisely controlled.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the configuration of a resist coating device according to an embodiment of the present invention, Fig. 2 is a diagram showing a cross section of the resist coating device of Fig. 1, and Fig. 3 is a diagram showing temperature and absolute film thickness of the resist film. It is a graph showing the relationship between 1...Chamber, 2...Liquid introduction pipe, 3...Semiconductor wafer 4...Spin chuck, 5...Photoresist Supply nozzle, 6... Bellows mechanism, 7... Air flow regulating plate, 10... Circulating constant temperature chamber, 11... Temperature regulating medium flow path, 2. ...Temperature sensor. Applicant Tokyo Electron Ltd.

Claims (1)

[Claims] (1) A coating apparatus that supplies a coating liquid to a substrate to be processed and rotates the substrate to apply the coating liquid onto the surface of the substrate to be processed, comprising: a chamber that accommodates the substrate to be processed; 1. A coating device comprising: a temperature adjustment mechanism provided within the chamber wall for adjusting the temperature.