JPH03291913A - Coating equipment for manufacturing semiconductor - Google Patents

Abstract

PURPOSE:To obtain an equipment which can restrain deterioration in the case of resist material whose characteristics may be deteriorated at a room temperature, and at the same time, prevent the generation of nonuniformity of a coating film and change of film thickness caused by local concentration change of resist solution, by installing a refrigeration unit, a low temperature accommodation unit, and a constant temperature unit which are individually specified. CONSTITUTION:A coating equipment wherein resist solution 8 is dripped on a semiconductor substrate 7 and spin-coating is performed is constituted of the following; a refrigeration unit 9 which preserves the resist solution 8 at a low temperature wherein said solution is not denatured, a low temperature accommodation unit 11 which maintains a filter 5 and a pump 6 connected with a coating solution supplying pipe 4 through which the resist solution 8 is sent, at a low temperature wherein the solution 8 is not denatured, and a constant temperature unit 10 which increases the temperature of the solution 8 in the coating solution supplying pipe 4 and keeps a specified coating temperature. For example, a chemical liquid bottle 2 containing the resist solution 8 is preserved in the refrigeration unit 9, which is cooled by a refrigerator and kept at a temperature lower than or equal to 10 deg.C. The low temperature accommodation unit 11 accommodating the filter 5 and the pump 6 is similarly cooled by the refrigerator.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to semiconductor manufacturing equipment, and particularly to a coating device for coating resist on various substrates.

(Prior Art) The manufacture of various semiconductors mainly consists of repeating the following baton forming process.

First, a thin film of an insulator, metal, etc. is deposited on a substrate, and then an organic polymer (commonly known as resist) solution made of a photosensitive resin is spin-coated to create a resist thin film. The spin coating is a method in which a resist solution in which a resist is dissolved in a predetermined solvent is poured onto a substrate from a nozzle, and then the substrate is rotated at a predetermined number of rotations to obtain a polymer film with a desired thickness. Next, a desired pattern is exposed onto the resist using ultraviolet rays, X-rays, electron beams, or the like. A desired resist pattern is formed through a development process, and the insulator,
A desired thin film pattern is obtained by etching a thin film of metal or the like. Therefore, the dimensional accuracy of the resist pattern influences the accuracy of the processed thin film batten, that is, the performance of the semiconductor.

The coating equipment for semiconductor manufacturing that has been commercially available so far is
The configuration is as shown in the figure. The resist solution 8 stored in the chemical solution [2 is sent to the nozzle 3 through the filter 5 by the pump 6, and is dripped onto the substrate 7 after being temperature-controlled to a constant coating temperature by the constant temperature section. In this case, the drug solution bottle, filter, pump, and piping are located at room temperature or at a motor for operating and controlling the device inside the device.

Due to the heat generated by the boards, the temperature is slightly higher than room temperature (25 to 3
0°C). As a result, the resist solutions in the drug bottles, filters, pumps, and piping are altered (thermal cross-linking between resist molecules, decomposition of photoreceptors, etc.), resulting in deterioration of characteristics such as sensitivity and resolution. For example,
SAL manufactured by Shipley Adva
nced lithography) resists, etc. are published in the Journal of Vacuum Science and Technology (Journal of VacuumSc
Science and Technology) Magazine, Volume B
6@, No. 1, 1988, pp. 379-383, it is known as a high-resolution, high-sensitivity electron beam chemically amplified resist, but even after more than half a year at temperatures below 10°C, Although no deterioration of the material was observed, it was confirmed that when the temperature exceeded 25° C., the deterioration became noticeable in 1 to 2 weeks, and both sensitivity and resolution decreased by several tens of percent. Moreover, the medicine liquid bottle,
From resist solutions in filters, pumps and piping,
As the solvent evaporates over time, the concentration of the remaining resist solution changes locally, resulting in uneven coating, which can cause the coating film to become uneven within the surface of the sea urchin, and the coating film thickness to vary between wafers. This caused a decrease in the dimensional accuracy of the resist pattern.

Until now, as a means to solve the above problem, as described in Japanese Patent Application No. 62-25331, a refrigerated section is installed to preserve the resist solution at a low temperature, and at the same time, the resist solution remaining in the piping system is removed using a solvent. A method of dissolving and removing it is known. Figure 2 shows an example of this.
The resist solution 8 is stored at a low temperature in a chemical liquid bottle 2 in a refrigerator section 9, heated to a predetermined temperature in a constant temperature section 10, and then dripped onto the substrate 7 by a nozzle 3. In this case, the temperature of the refrigeration unit is set so that deterioration of the resist solution and volatilization of the solvent from the resist solution do not occur, or are so low as to be negligible. This suppresses deterioration of the resist solution in the chemical bottle due to the influence of ambient temperature and concentration change due to solvent volatilization. Furthermore, after coating, the resist solution remaining in the filter, pump, and piping system is dissolved and removed by pumping the solvent 12 into the piping through the switching valve 13 as necessary. It also avoids deterioration and concentration changes, thereby preventing unevenness and variation in coating film thickness.

(11g to be Solved by the Invention) In the above-mentioned prior art, the resist solution is stored at a low temperature and, at the same time, the resist solution remaining in the pump, filter, and piping is dissolved and removed using a solvent. However, this method cannot completely remove the resist solution remaining in the microscopic gaps or microstructures in the filter and pump, and these residual resists may be heated to room temperature or slightly higher than room temperature due to surrounding heating elements. It had the disadvantage that it deteriorated due to being placed in the environment. In addition, like the resist solution, the solvent for dissolving and removing remains in the filter and pump, so during liquid delivery and application, these residual resist solutions, the solvent, and the resist solution sent from the chemical bottle in the refrigerator unit are mixed. The concentration of the coating solution may change locally, causing the coating film to become uneven.
There was also the problem that the film thickness fluctuated. Furthermore, the combined internal volume of the foreign matter removal filter and precision liquid delivery pump that are conventionally used for highly accurate control of the coating process reaches over 100 cc, which is about 2 cc for a 6-inch wafer.
This amount corresponds to the amount that can be applied to five sheets, and at least this amount is dissolved and removed every time the coating is done and thrown away.

The present invention has been made to solve the above-mentioned problems, and it is possible to suppress the deterioration of resist materials whose properties deteriorate at room temperature, and at the same time prevent the coating film from being affected by local concentration changes in the resist solution. Another object of the present invention is to provide a coating device that can prevent film thickness fluctuations and further minimize the amount of resist solution that becomes unusable.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a coating device that drips and spin-coats a resist solution onto a semiconductor substrate at a low temperature that does not cause deterioration of the resist solution. A refrigeration unit for storing the resist solution, a low-temperature storage unit that maintains the filter and pump connected to the coating solution supply piping through which the resist solution is fed at a low temperature that does not cause deterioration of the resist solution, and The gist of the invention is a coating apparatus for semiconductor manufacturing, which is characterized by comprising a constant temperature unit that raises the temperature of a resist solution to a predetermined coating temperature.

(Function) The present invention is equipped with a refrigeration unit that stores the resist solution at a low temperature that does not cause deterioration of the resist solution.
With respect to the resist solution stored in the refrigeration unit, deterioration of the resist solution due to the influence of ambient temperature and change in concentration of the resist solution due to volatilization of the solvent are suppressed. In addition, the filter and pump are kept at a temperature that does not cause deterioration of the resist solution in the low-temperature storage unit, so the resist solution remaining inside the filter and pump will not be affected by the effects of ambient temperature in the same way as the refrigeration unit. Changes in the concentration of the resist solution due to solution deterioration and solvent volatilization are suppressed.

Furthermore, since the resist solution in the coating liquid supply pipe is equipped with a constant temperature unit that can raise the temperature of the resist solution and maintain it at a predetermined coating temperature with high precision, the temperature of the coating liquid during coating is always kept constant. These avoid deterioration, concentration changes, and temperature changes of the resist solution caused by ambient temperature, and keep the inside of the wafer constant.
A coating film with constant and uniform thickness can be obtained from wafer to wafer.

(Example) Next, an example of the present invention will be described. It should be noted that the embodiments are merely illustrative, and it goes without saying that various changes and improvements may be made without departing from the spirit of the present invention.

FIG. 1 shows a configuration diagram of a coating apparatus for semiconductor manufacturing according to the present invention.

In the figure, soil is a coating device, 2 is a medicine bottle, 3 is a nozzle,
4 is piping, 5 is filter, 6 is pump, 7 is board, 8
9 indicates a resist solution, 9 indicates a refrigerator section, 1o indicates a constant temperature section, and 11 indicates a low temperature storage section.

The drug solution bottle 2 containing the resist solution 8 is stored in the refrigerator section 9. The refrigerator section 9 is cooled by a refrigerator and is normally maintained at 10° C. or lower. Furthermore, the low-temperature storage section housing the filter and pump is similarly cooled by a refrigerator and maintained at 10° C. or lower. The resist solution is sent from the refrigeration section 9 through the low-temperature storage section 11 via piping 4, and is kept at a coating temperature (23±0.1°C) in the constant temperature section 10, which is precisely controlled by constant temperature water.
), and then dropped onto the substrate from the nozzle 3.

In this embodiment, the piping from the low-temperature storage section to almost the tip of the nozzle is located in a constant temperature section and is temperature controlled.

(Example) A medicine bottle containing Silapray's 5AL-601-ER7 resist is stored in the refrigerator section whose temperature is maintained at 5"C, and a filter in the low-temperature storage section whose temperature is maintained at 10 degrees Celsius.
The resist solution was fed through a pump, the temperature of the resist solution was raised to 23° C. by a constant temperature section, and then the resist solution was dropped from a nozzle to obtain a coating film.

In an experiment using the resist of this example, in which the resist solution was left in the filter and pump for two weeks and then coated, when a conventional coating device equipped with only a refrigeration section and no low-temperature storage section was used, The film thickness variation within a wafer and between wafers was approximately 30%, and the sensitivity variation was 30%. On the other hand, with this device, both film thickness variation and sensitivity variation were below 3%.

Although the degree of characteristic change of the resist of this example at the coating temperature was low, if the degree of change is significant, it is possible to dissolve and remove the remaining liquid with a solvent after coating. In this case, the filter in the low temperature storage section and the resist solution in the pump are kept at the same temperature (10℃) as the refrigerator section, so there is no deterioration or solvent volatilization, and the resist solution remains in the piping after the low temperature storage section. In addition, since there are no minute gaps in the piping after the low-temperature storage section, the remaining solution can be completely removed. Since the length is designed to be 2 m or less (piping inner diameter 3-), even if it becomes necessary to dissolve and remove the resist solution, the amount of resist solution that is removed and becomes unusable can be suppressed to 20 cc or less.

(Effects of the Invention) As explained above, the coating apparatus according to the present invention includes a refrigeration unit that stores a resist solution to be coated on a semiconductor substrate at a low temperature that does not cause deterioration of the resist solution, and a refrigerator unit that stores the resist solution to be fed. a low-temperature storage unit that maintains a filter and a pump connected to the coating liquid supply pipe at a low temperature that does not cause deterioration of the resist solution; and a low temperature storage unit that heats the resist solution in the coating liquid supply pipe to a predetermined coating temperature. Since it is equipped with a constant temperature unit, even if the resist material has initial characteristics that deteriorate at room temperature, it is not only possible to keep the resist solution in the chemical bottle inside the device and perform coating work. Regarding the resist solution remaining in the filter and pump, it is possible to suppress material deterioration due to the influence of ambient temperature and local concentration changes due to solvent volatilization, and also avoid the influence of ambient temperature changes on the coating solution temperature. To realize a coating process that guarantees high dimensional accuracy by preventing non-uniformity of the coating film and variation in H thickness. Furthermore, since the amount of resist solution that remains in the filter pump and piping and becomes unusable after the coating operation is completed can be minimized, the amount of resist solution used can also be saved.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of a coating apparatus for semiconductor manufacturing according to the present invention, FIG. 2 shows an embodiment of a conventional coating apparatus having a refrigeration section and a constant temperature section, and FIG. 3 shows a conventional coating apparatus. 1... Coating device for semiconductor manufacturing 2... Chemical liquid bottle 3... Nozzle 4... Piping 5... Filter 6... Pump 7... ... Substrate 8 ... Resist solution 9 ... Refrigeration section 10 ... Constant temperature section 11 ... Low temperature storage section 12 ... Melting 13 ... Switching valve Figure 2

Claims (1)

[Claims] In a coating device that drips and spin-coats a resist solution onto a semiconductor substrate, it is connected to a refrigeration unit that stores the resist solution at a low temperature that does not cause deterioration, and to a coating solution supply pipe through which the resist solution is delivered. A low-temperature storage unit that holds the resist solution filter and pump at a low temperature that does not cause deterioration of the resist solution, and a constant temperature unit that raises the temperature of the resist solution in the coating solution supply pipe to a predetermined coating temperature. A coating device for semiconductor manufacturing characterized by the following.