JPH06313690A - Heat exchanger for semiconductor device etchant - Google Patents

Abstract

PURPOSE:To improve durability and temperature controllability of a heat exchanger main body against etchant chemicals by using fluorine resin- impregnated carbon material at least at a contact part of the body with the chemicals such as a predetermined part of a cooler. CONSTITUTION:Etchant chemicals of a heat exchanger main body are fed from a reservoir 1 to a cooler 3 via a tube 2 and then returned from a hole 4 to the reservoir 1 via a tube 5. On the other hand, coolant is circulated to be supplied from a storage tank 6 to a heat radiator 9 via a plurality of tubes 7, 8. The body heat exchanges the chemicals with the coolant in the case of wet etching a semiconductor device to control a temperature of the chemicals. With this structure, at least a contact part of the body with the chemicals such as a predetermined part of the cooler 3 is formed of fluorine resin- impregnated carbon material. Thus, durability and temperature controllability of the exchanger against the chemicals can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger suitable for controlling the temperature of an etching chemical used for manufacturing various semiconductor devices.

[0002]

2. Description of the Related Art Wet etching of semiconductor devices requires strict temperature control in order to achieve a high degree of dimensional accuracy. For this reason, the flow path for supplying an etching solution to an etching treatment apparatus is usually circulated. A heat exchanger is placed on the way to control the temperature.

An example of this type of heat exchanger is shown in FIG. FIG. 1 is a conceptual diagram for explaining a process of performing etching by a configuration example (cooler) of a heat exchanger for a semiconductor device etching liquid of the present invention, in which 1 is a storage tank for an etching chemical liquid, and a pipe. 2, the chemical solution is supplied to the cooler 3. The chemical liquid that has passed through the holes 4 formed in the cooler 3 is piped 5
To return to the storage tank 1. In the figure, reference numeral 6 denotes a storage tank of a cooler, which circulates and supplies cooling water to a radiator 9 through pipes 7 and 8. In the figure, 10 and 11 are headers for holding the cooler 3 and the radiator 9, respectively, and 12 is a thermoelement. Reference numeral 13 is a thermostat, and 14 is a cooler for adjusting the temperature of the cooling water.

Since the cooler 3 is in direct contact with the etching solution, it is necessary to have corrosion resistance against etching solution components such as hydrofluoric acid, nitric acid, hydrochloric acid and hydrogen peroxide solution.
For example, as cited or described in Japanese Utility Model Laid-Open No. 63-173680, conventionally, a fluorocarbon resin or a chemical resistant material such as alumina or silicon carbide coated with a fluorocarbon resin has been used.

However, a member made of only fluororesin has a low heat exchange efficiency because the fluororesin itself is a poor conductor of heat originally, and for example, when cooling the etching solution, it reaches a predetermined temperature. It takes a long time and the accuracy of temperature control at a predetermined temperature is poor. On the other hand, when the fluororesin is used as the coating, there is a problem that peeling occurs due to the difference in the coefficient of thermal expansion from the base material and that the chemical resistance deteriorates due to the pinholes.

Therefore, an attempt was made to use a carbon material such as graphite for the heat exchanger for the purpose of obtaining high corrosion resistance and increasing heat exchange efficiency. However, the carbon material itself is corroded by hydrofluoric acid or a highly oxidizable component. In addition, there is a problem that the corrosion product is released into the etching solution and contaminates the semiconductor device.

In view of the above-mentioned prior art, the present invention has been made to provide a heat exchanger having both high temperature control performance of the etching solution and high corrosion resistance to the etching solution.

[0008]

[Means for Solving Problems] That is, the above problems are
The heat exchanger for a semiconductor device etching liquid of the present invention uses a fluororesin-impregnated carbon material at least in a contact portion with the etching liquid.

[0009]

The heat exchanger for a semiconductor device etching liquid of the present invention has a structure as shown in FIG. 1, for example, and is in contact with all or at least the liquid of the cooler 3 in FIG. The circumference of the tube wall is made of the fluororesin-impregnated carbon material, and the fluororesin-impregnated carbon material used here is a composite material in which the pores of the carbon material molded body are impregnated with the fluororesin.

The carbon material is a material consisting essentially of carbon or a material containing carbon as a main component, and includes various carbon materials such as so-called carbonized products and graphitized products. this house,
High-density isotropic graphite that has been subjected to cold isostatic pressing with good uniformity of thermal conductivity is preferable, and particularly has a thermal conductivity of 80 kcal.
/ H · m · ° C or higher is preferable.

The fluororesin is preferably a low-melting fluororesin having a melting point of about 80 to 350 ° C. in view of ease of impregnation. The impregnation operation is performed by, for example, melt-impregnating the fluorocarbon resin into the carbon material under appropriate pressure conditions depending on the properties of the molten fluorocarbon resin, particularly the viscosity in a pressure vessel, whereby at least the surface layer portion of the carbon material is obtained. The fluororesin uniformly permeates the pores of the carbon material and coats the inner walls of the pores. The fluororesin adhering to the surface of the carbon material is removed with a spatula or the like.

As described above, by using the fluororesin-impregnated carbon material in at least the portion of the heat exchanger that comes into contact with the etching solution, the corrosion resistance of the heat exchanger against the etching solution is increased, and the heat exchanger is made of only the fluororesin. The heat exchange performance is improved as compared with the case where a member coated with a fluororesin is used. Further, the impregnated fluororesin is stably held in the pores, does not cause peeling, and has no pinhole.

[0013]

The present invention will be described in more detail with reference to the following examples.

[0014]

Example 1 As the cooler 3 of the heat exchanger shown in FIG.
The high-density isotropic graphite having a thermal conductivity of 120 kcal / h · m · ° C impregnated with a fluororesin having a melting point of 150 ° C according to the present invention, the same graphite or fluororesin (polytetrafluorocarbon) not impregnated with a fluororesin as described above The temperature of the outlet of the etching liquid, the temperature of the contact surface with the liquid of the cooler 3 and the temperature of the cooling element 12 are measured by circulating the etching liquid using a member made of only fluoroethylene), and the energy is calculated from the respective differences. The conversion efficiency was calculated. The results are shown in Table 1.

[0015]

[Table 1]

From Table 1, it is found that the fluororesin-impregnated graphite according to the present invention has remarkably high energy conversion efficiency as compared with the member made of only the fluororesin, and has substantially the same performance as the member made of only graphite. . Also, the outlet control temperature was almost the same as in the case of the member made of only graphite, and could be well controlled.

It was also confirmed that when the fluororesin-impregnated graphite according to the present invention was used, fluctuations in temperature change during temperature control were significantly reduced.

[0018]

Example 2 As the cooler 3 of the heat exchanger shown in FIG.
Using the fluororesin-impregnated graphite of the present invention, 50% nitric acid, 36% hydrochloric acid, 30% hydrogen peroxide solution, and 46% hydrofluoric acid were circulated at 22 ° C. for 24 hours, respectively, and an elution test was conducted.
Table 2 shows the three types of eluted components with high elution amounts and their amounts.

[0019]

[Table 2]

From Table 2, it was found that when the fluororesin-impregnated graphite according to the present invention was used, the elution amount was extremely small and the etching liquid had sufficient corrosion resistance as a heat exchanger.

[0021]

As demonstrated by the above embodiments, the heat exchanger for semiconductor device etching liquid of the present invention has both high corrosion resistance against etching liquid and high temperature control performance of the etching liquid, and can be used for a long period of time. The fluororesin does not peel off.

[0022]

[Brief description of drawings]

FIG. 1 is a conceptual diagram for explaining a process of adjusting temperature by a configuration example of a heat exchanger for a semiconductor device etching liquid according to the present invention.

[Explanation of symbols]

 1 Etching liquid storage tank 3 Cooler 6 Cooling liquid storage tank 9 Radiator 12 Thermo element 14 Cooler

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Morinobu Endo 615 Kitahara-cho, Suzaka City, Nagano Prefecture (72) Inventor Kai Tsuboi 246, Takako, Suzaka City, Nagano Orion Machinery Co., Ltd. (72) Inventor Ryoji Kobayashi Orion Machinery Co., Ltd., 246 Kodaka, Suzaka City, Nagano Prefecture

Claims (1)

[Claims] 1. A heat exchanger for a semiconductor device etching liquid, wherein a fluororesin-impregnated carbon material is used at least in a contact portion with the etching liquid.