JPS621546B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a coating device for an organic polymer solution such as a resist.

Conventionally, in lithography for forming integrated circuit patterns, a resist solution is applied onto a semiconductor substrate, baked, and then a desired pattern portion is exposed to light and a development process is performed to form the desired pattern. Such lithography technology is widely used in the manufacture of semiconductor devices.
To form a resist film in the lithography process described above, the method of dropping a resist solution onto a semiconductor substrate and then spin coating is mainly used in the manufacturing process of highly integrated circuits.Other methods include spray method, coater method, etc. There is.

Regarding the conventional resist coating spinner device, the first
This will be explained with reference to the figures. In FIG. 1, 1 is a pressurized tank containing a resist solution 2 with a capacity of several liters, 3 is a pressurized gas pipe opened at the top of the pressurized tank 1, and 4 is connected at one end to the bottom of the pressurized tank 1. , a transfer pipe having a dripping port 5 at the other end, 6 a filter provided on the transfer pipe 4, 7
A wafer is a semiconductor substrate mounted on a rotating device 9 rotated by an electric motor 8, and the dropping port 5 is disposed on the wafer 7.

In the resist coating spinner device configured as described above, pressurized gas is sent from the pressurized gas pipe 3 to the pressurized tank 1 to pressurize the inside of this tank, thereby transferring the resist solution in the pressurized tank 1 to the transfer pipe 4. Then, it is sent to the dripping port 5 through the filter 6, and dripped onto the wafer 7 from the dripping port 5. Thereafter, the resist solution is spin-coated onto the wafer 7 by driving the electric motor 8 of the rotating device 9 .

In conventional devices like this, most resist solutions can be stored for the longest time by storing them at room temperature, i.e., at a temperature of about 20°C. It was not seen as necessary. However, the formation of the resist coating film described above,
Since high precision is increasingly required in the exposure process and control of pattern dimensions, high precision is required, and temperature control of the resist solution is now required.

That is, since the conventional resist coating apparatus described above is not equipped with a means for controlling the temperature of the resist solution, the viscosity of the resist solution may fluctuate, resulting in slight variations in resist film thickness or uneven coating. These have led to dimensional changes in the formation of highly integrated circuit patterns.

In addition to the resist film, thermosetting polymer films, typically polyimide, are now being used as semiconductor integrated circuit structures. For example, with the increasing density of integrated circuits, it is necessary for metal wiring to have a multilayer structure, and polyimide films are used as insulators between the interconnects in the multilayer structure. Thermosetting polymer films are also becoming more important for protection.

However, thermosetting resins, such as polyimide, have an extremely short storage life at room temperature and become highly viscous in a short period of time when left at room temperature. As a result, it becomes extremely difficult to form a polyimide film with a uniform thickness.

Furthermore, organic polymer solutions such as resist at the drip opening of conventional coating devices have the disadvantage of solidifying because they are constantly left in the surrounding air. There is a problem in that it is forced and the process becomes complicated.

This invention is an attempt to eliminate the above-mentioned drawbacks of the conventional coating equipment, and involves cooling an organic polymer solution such as a resist, polyimide, or silane in a tank, and then heating the cooled solution. The resist film, polyimide film, and organic silane film are formed to a uniform thickness by circulating the solution outside the tank, including the inside of the solution dripping port, and opening the opening/closing door provided inside the dripping port to drip the solution. The purpose of the present invention is to provide an organic polymer solution coating device that can coat an organic polymer solution.

2 and 3 for one embodiment of this invention.
This will be explained with reference to the figures. In FIG. 2, 11 is a pressurized tank containing the resist solution 12, 13 is a cooling storage container containing this tank 11,
The cooling storage container 13 constitutes a cooling means for cooling the resist solution in the tank 11. 14 is a pressurized gas pipe that opens at the upper part of the tank 11; 15 is a transfer pipe that opens at the lower part of the tank 11 and extends into the tank 11;
4 are configured. Reference numeral 16 denotes a constant temperature heating device provided at the tip of the transfer pipe 15. The outgoing pipe 19 and the returning pipe 20 of the circulation means 25 are connected to the leading end of the heating device 16. The outgoing pipe 19 is connected to the pump 1.
7. It passes through the filter 18 and reaches the drip opening. As shown in FIG.
9 is the large diameter portion 21 of the return pipe 20 covering the tip thereof.
It is opened directly above the solution dripping port 22 provided at the lower end,
The return pipe 20 is a constant temperature heating device 1 on the suction side of the pump 17.
6 and is connected to an outgoing pipe 19. A drip port opening/closing door 23 that opens inward is provided inside the drip port 22. Further, a wafer 28 mounted on a rotating device 27 horizontally rotated by an electric motor 26 is disposed directly below the dripping port 22 .

In the resist coating spinner device configured as described above, the tank 11 is housed in the cooling storage container 13 to stabilize the storage characteristics of the resist solution 12 in the tank 11. In this case, tank 11
In order to keep the viscosity of the resist solution constant by cooling the entire resist solution, it is preferable to maintain the resist solution at about -10°C.

In addition, the resist solution cooled in the tank 11 is transferred to the outside of the tank 11 through the transfer pipe 15 by sending pressurized gas into the tank 11 from the pressurized gas pipe 14, as in the case of a conventional coating device. It will be done. The resist solution transferred to the outside of the tank 11 is maintained at about 20° C. by a constant temperature heating device 16 to adjust the coating viscosity.

The resist solution whose viscosity has been adjusted is pumped to the pump 17.
After passing through a filter 18 to remove particulates and dust, the water is sent to a drip port 22. If there is no need to drop resist, as shown in Figure 3,
The opening/closing door 23 of the dropping port 22 is closed, and the resist solution is introduced from the outgoing pipe 19 into the returning pipe 20, returns to the constant temperature heating device 16 through the inside of the dropping port 22, and is guided from there to the outgoing pipe 19 for circulation. When dropping the resist solution, the opening/closing door 23 is opened and the resist solution is dropped onto the wafer 28 from the dropping port 22. Therefore, since the resist solution is constantly circulated through the drip opening 22, there is no solidification or adhesion of the solution.

As explained above, the coating apparatus according to the embodiment of the present invention cools the resist solution in the tank 11, and heats the resist solution transferred outside the tank 11 with the constant temperature heating device 16 to reduce the viscosity of the solution. By adjusting the resist solution and constantly circulating the resist solution at the resist dripping opening, (i) the viscosity characteristics of the resist solution are uniform, and (ii) the resist at the resist dripping opening does not solidify. For this reason, when applying resist to a wafer, there is no need to clean the dripping port, which eliminates complexity, and there is no chance of solidified resist getting mixed into the applied resist solution, resulting in pattern defects. There are no problems such as this, and the resist can be formed to have a more uniform thickness. Therefore, there are advantages in that the quality of patterning of highly integrated circuits is improved and the yield of devices is improved.

In the above embodiments, coating of a resist solution was described, but the coating apparatus of the present invention can be widely applied to coating of organic polymer solutions such as polyimide precursors and organic silane solutions.

As mentioned above, the coating device according to the present invention has the following features:
It has a cooling means for cooling the organic polymer solution in the tank, a constant temperature heating device for adjusting the viscosity of the solution in the tank, and a circulation means for circulating the solution outside the tank including a solution dripping port. Therefore, it has the effect of always being able to apply a solution such as a resist to a uniform film thickness with high precision, and is suitable for use in VLSI manufacturing.

[Brief explanation of the drawing]

FIG. 1 is a configuration explanatory diagram showing a conventional coating device;
FIG. 2 is a configuration explanatory diagram showing a coating device according to an embodiment of the present invention, and FIG. 3 is a side sectional view of the same drip opening. 11...tank, 12...resist solution, 13...cooling storage container (cooling means), 14...pressurized gas pipe, 15...transfer pipe, 16...constant temperature heating device, 1
7... Pump, 18... Filter, 19... Outgoing pipe, 2
0...Return pipe, 21...Large diameter section, 22...Dripping port, 23
...Opening/closing door, 24...Transfer means, 25...Circulation means, 2
6...Electric motor, 27...Rotating device, 28...Wafer.

Claims (1)

[Claims] 1. A tank containing an organic polymer solution such as a resist, a cooling means for cooling the solution contained in this tank, a transfer means communicating with the tank and transferring the solution to the outside of the tank, and this transfer means. a circulation means that circulates the solution outside the tank including the inside of the solution dripping port, a constant temperature heating device that heats the solution outside the tank to a predetermined temperature, and a dripping port opening/closing door provided inside the dripping port. An organic polymer solution coating device comprising: