JPH08138989A - Method and apparatus for treatment of organic impurities - Google Patents

Abstract

PURPOSE: To obtain an apparatus by which the amount of organic impurities having a bad influence on a semiconductor device is reduced simply and with good efficiency even under a high temperature by a method wherein hydrogen which is obtained by decomposing moisture in the air is added to an organic substance comprising an unsaturated carbon bond so as to be converted into saturated hydrocarbon. CONSTITUTION: An ultraviolet lamp 16 is turned on, and a blowing part 13 is operated. Then, when the air A which has been taken into from an intake port 15 is passed inside a filter 17 for a cut-off 14, reactive radicals and ions are generated by a catalyst and ultraviolet rays. Organic impurities caused by a plastic additive or the like are contained in the air A, they comprise an unsaturated carbon bond or the like, and they are easily adsorbed to the surface of a semiconductor substrate so as to have a bad influence on a semiconductor device. The harmful organic impurities are easy to decompose when they are passed inside the cut-off 14, and unsaturated hydrocarbon is reacted with the reactive hydrogen radicals and the ions so as to be converted into saturated hydrocarbon. Consequently, the amount of the organic impurities in the air can be reduced simply an with good efficiency even under a high temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for treating organic impurities contained in air, particularly for reducing the amount of organic impurities which adversely affect the production of semiconductor devices.

[0002]

2. Description of the Related Art As is well known, semiconductor devices have been highly integrated and miniaturized due to demands for miniaturization and high functionality of equipment in which semiconductor devices are mounted. Along with this, demands for the performance of insulating films and precision of microfabrication technology for semiconductor devices have become higher, and as a result, the influence of trace organic impurities contained in the air of the semiconductor device manufacturing environment has become a problem.

That is, a small amount of organic impurities in the air are adsorbed on the surface of a semiconductor substrate in a semiconductor device manufacturing process, and have a bad influence on deterioration of insulation property of an insulating film, abnormal shape of a thin film, deterioration of adhesion property of a film, It has been clarified that it may be adsorbed on an optical system component of a microfabrication device and cause deterioration of the device performance.

Therefore, it is necessary to remove the organic impurities in the air in the clean room for semiconductor manufacturing or in the clean booth or the air around the manufacturing equipment so as to be below a predetermined limit.

Under such circumstances, conventionally, the organic impurities in the air have been removed as described below with reference to FIG. FIG. 5 is a conceptual diagram of a main part.

In FIG. 5, reference numeral 1 is a filter using activated carbon or a polymeric adsorbent, and a large number of fine holes 2 are formed on the surface thereof.
Is provided. Then, by flowing air so as to pass through the filter 1, impurities 3 such as organic substances contained in the air are physically adsorbed by the fine pores 2 on the surface of the filter 1.

Although not shown, such a filter 1 is provided at an air intake port of a clean room for semiconductor manufacturing, for example, and is used so that only the air passing through the filter 1 is fed into the clean room. Then, as the air sent into the clean room passes through the filter 1, impurities 3 such as organic substances are captured by the filter 1,
The atmosphere in the clean room is maintained at an impurity concentration below a predetermined limit.

As a result, the amount of air passing through the filter 1 increases as the use time elapses, and accordingly, the amount of the impurities 3 physically adsorbed in the pores 2 on the surface of the filter 1 increases, and the pores 2 gradually increase. It is filled with impurities 3. Therefore, the removal efficiency of the impurities 3 of the filter 1 gradually decreases, and it is necessary to replace the filter 1 after a predetermined time so as to keep the impurity concentration in the clean room below a predetermined limit.

When the filter 1 is replaced, the life of the filter 1 varies depending on the concentration of impurities such as organic substances in the air. Even if the filter 1 is set to be replaced at regular intervals in advance, the concentration of impurities in the air is changed. If the value is high, the impurity concentration in the clean room may exceed a predetermined limit without waiting for the set time. Therefore, it is necessary to always measure the concentration of the impurities 3 in the air before and after the filter 1 in order to know the replacement time, which is troublesome.

Further, when the impurities 3 are removed by the filter 1, only the organic components out of the impurities 3 in the air, which are easily adsorbed on the surface of the semiconductor substrate or the surface of the device parts and have a great influence on the semiconductor device. Not only that, but also all organic components, which are difficult to adsorb and have little influence on the semiconductor device, are collected and removed, so that the life of the filter 1 is shortened. For this reason, the frequency of replacement of the filter 1 is increased, and this is also troublesome.

Further, since the impurities 3 are physically adsorbed on the filter 1 to remove the impurities, if the filter temperature rises for some reason, the adsorbed impurities 3 may be released again. In addition, since the adsorption efficiency decreases in an environment where the temperature is higher than room temperature and impurities cannot be removed sufficiently, the use in a high temperature environment that generates heat is further restricted, and the filter 1 after installation is
There was a situation where it would be difficult to replace or control the concentration of impurities.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above situation, and an object thereof is to remove harmful organic impurities which adversely affect a semiconductor device among organic impurities in the air. An object of the present invention is to provide a method and an apparatus for treating organic impurities, the amount of which can be reduced easily and efficiently even at high temperature.

[0013]

The method and apparatus for treating organic impurities according to the present invention is a method for adding hydrogen obtained by decomposing water in air to an organic substance having an unsaturated carbon bond contained in the air to achieve saturation. The method is characterized by converting to hydrocarbons, and is characterized by adding hydrogen obtained by decomposing water in air to an organic substance having an ester bond contained in the air to reduce to alcohol. Is a way to
The hydrogen obtained by decomposing water in the air is a reactive one obtained by decomposing in the presence of ultraviolet rays and a catalyst, and the molecular weight of the organic matter contained in the air is 200 or more. This is a method characterized in that the amount of harmful organic impurities in the air is reduced by converting or decomposing the impurities into molecules having a molecular weight of 100 or less, and further, the intake port and the exhaust port. A main body case in which the air blower is formed, a blower unit provided in the main body case, a removing unit provided in a flow passage of air taken into the main body case by the blower unit, and a removing unit provided in the removing unit. And a filter means having a catalyst provided in the removing portion so as to receive the irradiation of ultraviolet rays from the ultraviolet ray emitting means,
Furthermore, the filter means is characterized in that it is made of a porous body carrying a catalyst on the surface,
Further, the catalyst is characterized in that it is either Pt or TiO2.

[0014]

In the method and apparatus for treating organic impurities configured as described above, the treatment method adds hydrogen obtained by decomposing water in air to an organic substance having an unsaturated carbon bond contained in the air. Is converted to saturated hydrocarbons, or is added to an organic substance having an ester bond contained in the air to reduce it to an alcohol, whereby an organic substance having an unsaturated carbon bond in the air or an organic substance having an ester bond. The amount of can be decomposed only by the reaction with hydrogen obtained by decomposing water contained in the same air as these organic substances, and can be easily reduced. Further, in the processing apparatus, a removing unit is provided in the flow path of the air taken in by the air blowing unit provided in the main body case, and the removing unit has the ultraviolet radiation means and the catalyst provided to receive the irradiation of the ultraviolet rays. Since the filter means is provided, the moisture in the air taken in at the removing portion is decomposed by ultraviolet rays in the presence of the catalyst to obtain reactive hydrogen, and the hydrogen is added. Decomposition of harmful organic impurities occurs, and the amount of harmful organic impurities in the air can be efficiently reduced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a perspective view showing a schematic structure with a part thereof cut away, FIG. 2 is a characteristic diagram showing changes in the number of days left on a semiconductor substrate and a surface contact angle, and FIG. 3 is a use time and an organic impurity removal rate. FIG. 4 is a characteristic diagram showing the relationship between FIG. 4 and FIG.

According to the present invention, among the impurities contained in the air such as the semiconductor device manufacturing environment obtained by the inventors,
Adhesives that are easily adsorbed on the surface of semiconductor substrates and device parts, and that adversely affect the insulation of insulating films of semiconductor devices, the shape of thin films, the deterioration of film adhesion, and other harmful organic impurities are caused by plastic additives. The molecular weight contained in a very small amount is more than 100, and the one having a particularly bad influence is a molecular weight of 200 or more. On the other hand, it was carried out based on the finding that those having a molecular weight of 100 or less have no adverse effect. As organic impurities that adversely affect the semiconductor device, dibutyl phthalate (molecular weight: 278) and dioctyl phthalate (molecular weight: 390) are used in the phthalate system, and dibutyl adipate (molecular weight is used in the aliphatic dibasic acid ester system). : 258), dibutyl sebacate (molecular weight: 314), and ethylethenylbenzene (molecular weight: 132).

In FIG. 1 to FIG. 4, 11 is a processing apparatus for organic impurities, and a blower section 13 and a removing section 14 are provided in the main body case 12 of the processing apparatus 11 so as to divide the inside into two parts. The blower unit 13 is configured by providing a blower therein, and an intake port 15 for taking in the air A is formed on the left side in FIG.

The removing unit 14 has a wavelength of 200 nm to 2 nm.
A plurality of UV lamps 16 as UV radiating means for radiating UV of 50 nm are provided, and a filter 17 as a filter means is provided so as to surround the UV lamps 16 and to traverse the flow path of the air A in the removing section 14. Has been.

This filter 17 has P on the surface of the porous body.
t, TiO _{2 and} other catalysts are supported. An exhaust port 18 is formed on the right side of the removal unit 14 in FIG. 1 to allow the air A taken in from the intake port 15 to flow through the main body case 12 and then to be exhausted.

As a result, in the processing device 11, the intake port 15
The air A taken into the air blower 13 from the air blower 13 is sent from the air blower 13 to the remover 14 in the main body case 12, passes through the filter 17 of the remover 14, and is discharged to the outside from the exhaust port 18.

With the above-described structure, when the ultraviolet lamp 16 is turned on and the blower 13 is operated, the intake port 1
The air A taken in from the No. 5 filter 17 of the removing unit 14
When passing through the inside, Pt, Ti supported on the surface of the porous body
By the catalyst such as O ₂ and the ultraviolet rays from the ultraviolet lamp 16,
H ₂ O contained in the air is decomposed and H., H ⁺ ,
· OH, OH ^- reactive radicals and ions such are generated.

The reactive radicals and ions generated in the removing section 14 react with the organic impurities contained in the air to convert or decompose the organic impurities. Then, the air A containing the products of the decomposition is exhausted from the exhaust port 18.

However, most of the organic impurities in the air A are usually low molecular weight (100 or less) alcohols and saturated hydrocarbons, and since these organic impurities are difficult to adsorb on the surface of the semiconductor substrate, they adversely affect the semiconductor device. It is harmless and does not usually cause any problems. Then, such low molecular weight organic impurities do not easily react with reactive radicals or ions, and the removal unit 14 is used as it is.
Is discharged through.

On the other hand, the air A contains a small amount of organic impurities derived from a plastic additive having a large molecular weight (100 to 200 or more). Such organic impurities have unsaturated carbon bonds, ester bonds, etc., and are easily adsorbed on the surface of the semiconductor substrate, resulting in adverse effects such as deterioration of insulation properties of semiconductor device insulating films, abnormal thin film shapes, and deterioration of film adhesion. It is harmful.

Since such harmful organic impurities easily react with the reactive radicals and ions generated from H ₂ O in the air A, they are easily decomposed when passing through the removing section 14, and, for example, An unsaturated hydrocarbon having an unsaturated carbon bond reacts with a reactive hydrogen radical or ion as shown in the following formulas (1) and (2) to be converted into a saturated hydrocarbon. R-CH = CHR '+ 2H · → R-CH 2 -CH 2 -R' ... (1) R-CH = CHR '+ 2H + → R-CH 2 -CH 2 -R' ... (2)

The compound having an ester bond is reduced to an alcohol by reacting with a reactive hydrogen radical or ion as shown in the following formulas (3) and (4). RCOOR '+ 4H ・ → RCH ₂ OH + R'OH (3) RCOOR' + 4H ⁺ → RCH ₂ OH + R'OH (4)

By such a reaction, unsaturated hydrocarbons and ester compounds that are easily adsorbed on the surface of the semiconductor substrate can be decomposed into saturated hydrocarbons and alcohols that are difficult to adsorb.

For example, ethylethenylbenzene having a molecular weight of 132 is converted into diethylbenzene having a molecular weight of 134.

Dibutyl phthalate having a molecular weight of 278 has a molecular weight of 7 with xylenediol having a molecular weight of 134.
Dioctyl phthalate having a molecular weight of 390 is reduced to 2 molecules of butanol of 4 and xylene diol having a molecular weight of 134 and two octal molecules having a molecular weight of 130,
Dibutyl adipate with a molecular weight of 258 has a molecular weight of 128.
Of hexanediol and 2 molecules of butanol having a molecular weight of 74 are reduced, and dibutyl sebacate having a molecular weight of 314 is reduced to decanediol having a molecular weight of 184 and 2 molecules of butanol having a molecular weight of 74.

Further, the reactive radical OH · generated from H ₂ O in the air A acts as a strong oxidant and has an action of oxidatively decomposing organic substances, and as a result, the molecular weight which is easily adsorbed on the semiconductor substrate surface is increased. A high molecular weight organic substance having a molecular weight of 200 or more is decomposed into a low molecular weight organic substance having a molecular weight of 100 or less, which is difficult to adsorb.

Therefore, the removal performance of harmful organic impurities that adversely affect the semiconductor device of the processing apparatus 11 having the above-mentioned configuration was confirmed. The confirmation is based on the fact that the surface contact angle of the semiconductor substrate corresponds to the amount of adsorbed organic matter, and the surface contact angle increases as the amount of adsorbed organic matter increases. The semiconductor substrate was left to stand and the surface contact angle of the semiconductor substrate was measured.

The measurement results are as shown in the characteristic diagram of the number of days left for the semiconductor substrate and the change in the surface contact angle shown in FIG. 2, and almost no increase in the surface contact angle was observed in the semiconductor substrate left in the exhaust port 18. On the other hand, an increase in the surface contact angle was observed in the semiconductor substrate left in the intake port 15. It can be seen from this that the organic impurities adsorbed on the surface of the semiconductor substrate are effectively decomposed in the processing apparatus 11.

Further, the performance change due to continuous use was compared with a conventional device having a filter of activated carbon. The comparison was made by measuring the removal rate of harmful organic impurities from the amount of organic substances adsorbed on each surface of the semiconductor substrate left in the intake port 15 and the exhaust port 18 of the processing apparatus 11. The comparison result is as shown in the characteristic diagram of the usage time and the removal rate of the organic impurities shown in FIG. 3, and the treatment apparatus 11 of the present invention shows no reduction in the removal rate, whereas the conventional apparatus shows the time passage. At the same time, the removal rate is gradually decreasing. Therefore, the processing apparatus 11 of the present invention does not require periodic performance evaluation during use, life management, or the like.

Further, regarding the relationship between the use environment temperature and the organic impurity removal performance, the intake port 15 of the processing apparatus 11 is also the same.
The removal rate of harmful organic impurities was measured from the amount of organic substances adsorbed on each surface of the semiconductor substrate left in the exhaust port 18 by changing the environmental temperature. According to this, in the treatment apparatus 11 of the present invention, the performance tends to be slightly improved due to the activation of the reaction as the temperature rises, whereas in the conventional apparatus, the performance decreases as the temperature rises.

As compared with the above, among the organic impurities in the air A taken into the processing apparatus 11, the high molecular weight organic matter which is easily adsorbed on the surface of the semiconductor substrate is efficiently converted or decomposed into the low molecular weight organic matter, The air A, which does not contain harmful organic impurities that adversely affect semiconductor device manufacturing, is exhausted from the exhaust port 18.

Then, Pt, T carried by the filter 18
Since iO _{2 and the} like act as a catalyst, they do not deteriorate even when the operation is continued for a long time, and the predetermined organic impurity removal performance can be maintained only by controlling the ultraviolet lamp 16. Is very easy.

Since harmful organic impurities that adversely affect the manufacture of semiconductor devices are decomposed, the problem that the air A discharged from the processing apparatus 11 is re-polluted due to the desorption of the organic impurities does not occur. It is also possible to install it in a manufacturing process or equipment that involves high temperature environment or heat generation.

Further, for example, when the atmosphere in a clean room for semiconductor production (not shown) is kept at an impurity concentration below a predetermined limit, the processing apparatus 1 configured as described above is used.
The exhaust port 18 of No. 1 and the air intake port of the clean room may be simply attached so as to communicate with each other. Then, by operating the processing apparatus 11, the air A that does not contain harmful organic impurities that adversely affect the semiconductor device manufacturing is supplied from the exhaust port 18 into the clean room through the air intake port. The following impurity concentrations are maintained.

In the above embodiment, the filter 17
Was constituted by supporting a catalyst such as Pt and TiO _{2 on} the surface of the porous body. However, the catalyst such as Pt and TiO ₂ may be formed into a fibrous or particulate form as it is to form a porous body. The configurations of the ultraviolet lamp 16 and the filter 17 of the removing unit 14 are not limited to those described above, and the removing unit 1
H ₂ O contained in the air A is H., H ⁺ , .OH, OH due to the ultraviolet rays and the catalyst while the air A flows through the inside of 4.
^- it is sufficient to configure so as to be decomposed into reactive radicals and ions and the like. Further, although ultraviolet rays having a wavelength of 200 nm to 250 nm are used, the same effect can be obtained by using ultraviolet rays having a wavelength of 100 nm to 300 nm.

[0040]

As is apparent from the above description, according to the present invention, the amount of harmful organic impurities that adversely affect the semiconductor device in the air can be reduced easily and efficiently even at high temperature. Produce the effect of.

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic configuration of an embodiment of the present invention with a part cut away.

FIG. 2 is a characteristic diagram showing changes in the number of days left to stand and a surface contact angle of a semiconductor substrate according to an example of the present invention.

FIG. 3 is a characteristic diagram showing a usage time and an organic impurity removal rate according to an embodiment of the present invention.

FIG. 4 is a characteristic diagram showing the environmental temperature and the removal rate of organic impurities according to an embodiment of the present invention.

FIG. 5 is a conceptual diagram of a main part according to a conventional technique.

[Explanation of symbols]

 11 ... Processing device 12 ... Main body case 13 ... Blower part 14 ... Removal part 16 ... UV lamp 17 ... Filter A ... Air

Claims (7)

[Claims] 1. A method for treating organic impurities, characterized in that hydrogen obtained by decomposing water in air is added to an organic substance having an unsaturated carbon bond contained in the air to convert it to saturated hydrocarbon. 2. A method for treating organic impurities, characterized in that hydrogen obtained by decomposing water in air is added to an organic substance having an ester bond contained in the air to reduce it to alcohol. 3. The hydrogen according to claim 1 or 2, wherein the hydrogen obtained by decomposing water in the air is a reactive one obtained by decomposing in the presence of ultraviolet rays and a catalyst. Method for treating organic impurities. 4. The amount of harmful organic impurities in the air is reduced by converting or decomposing organic impurities having a molecular weight of 200 or more contained in the air into molecules having a molecular weight of 100 or less. A method for treating organic impurities, characterized in that 5. A main body case having an intake port and an exhaust port formed therein, a blower unit provided in the main body case, and a flow passage for air taken into the main body case by the blower unit. A removing unit; an ultraviolet radiating unit arranged in the removing unit; and a filter unit having a catalyst provided in the removing unit so as to receive irradiation of ultraviolet rays from the ultraviolet radiating unit. An apparatus for treating organic impurities, characterized by: 6. The apparatus for treating organic impurities according to claim 5, wherein the filter means is made of a porous material carrying a catalyst on its surface. 7. The apparatus for treating organic impurities according to claim 5, wherein the catalyst is either Pt or TiO2.