JP2003282518A - Removal method of organic film, and remover - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method wherein the range of an organic film turning to an object to be removed of a treatment solution in which an ozone gas is dissolved can be enlarged and the peeling speed and wettability of a resist film can be improved, a method wherein effective removed is likewise enabled to not only a resist but also a coating film, an oil film, etc., a method for regenerating the treatment solution, and removing the agent of an ozone gas resoluble organic film. <P>SOLUTION: 1. In this removal method of an organic film, the treatment solution in which an ozone gas is dissolved is brought into contact with a base material which has an ozone gas resoluble organic film on its surface, and the organic film is removed. The treatment solution is a solution containing (a) an organic substance which can dissolve the organic film and is hard to be dissolved by ozone and (b) an organic solvent wherein one or a plurality of kinds of organic solvents whose distribution coefficient to ozone in gas is at least 0.6 at room temperature and which are hard to be dissolved by ozone are mixed (where the organic substance and/or at least one kind of the organic solvents are water-soluble). 2. The remover of the ozone gas resoluble organic film as the treatment solution used in the method is provided. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing an organic film deposited on a substrate for cleaning the surface of an electronic device substrate or the like. Specifically, it relates to the removal of photoresist coatings used in the processing of semiconductor wafers or liquid crystal substrates, and the removal of organic contamination coatings on these substrates. Furthermore, the present invention can be applied to the removal of general organic coatings such as oil films and coating films on substrates.

[0002]

2. Description of the Related Art A photoresist used for microfabrication of an oxide film or a polysilicon film is usually removed by a mixed solution of sulfuric acid (3 or 4 volumes) and hydrogen peroxide (1 volume) (called piranha). It is widely used to heat at 11O-140 ℃ and soak for 1-20 minutes. In the piranha treatment, the resist decomposes, so it can be repeatedly treated with the same liquid, but hydrogen peroxide rapidly decomposes into water, and concentrated sulfuric acid has a strong hygroscopic property, so the water content of the liquid gradually increases and dilutes. Because
The peeling ability deteriorates and it can be used repeatedly only about a dozen times. A device for diluting the diluted waste liquid to increase the concentration and recycling has been introduced, but it has a problem in economic efficiency, and sulfuric acid is the most used chemical in the semiconductor industry. Furthermore,
Since it is subjected to high-temperature treatment, it also emits a large amount of acid gas, and both exhaust and drainage have a large impact on the environment.

For resist removal in the case of processing a wiring metal film, heat treatment with an organic solvent such as n-methylpyrrolidone (NMP), dimethylsulfoxide (DMSO) or amines is performed. Since these chemicals merely dissolve the resist but do not decompose it, the concentration of the dissolved component increases rapidly when the same liquid is repeatedly used, and it can be used only about 5 to 6 times. Further, if these chemicals contain water, there is a risk of damaging the metal film, and therefore, replacement with a solvent such as isopropyl alcohol is necessary before rinsing with pure water. Therefore, the required amount of organic solvent is further increased. Therefore, not only is it difficult to take measures against exhaust gas and drainage, but the organic solvent is generally expensive, so there is a problem in economical efficiency.

Therefore, recently, a gas containing a high concentration of ozone
Environmentally friendly resist removal using (hereinafter referred to as ozone gas) and water has been attempted. However, in such ozone water treatment, in the case of a novolac resin-based positive resist film for I-line, which is widely used in LSI manufacturing, the stripping speed is about 1 μm / min, and there is no margin in stripping ability, so its application is limited. It In order to fundamentally solve the slow stripping rate of ozone water treatment, the present inventor has used an organic solvent having a high ozone dissolving ability, such as acetic acid, and has a strong ability to decompose organic substances of ozone and a resist dissolving ability of the solvent. A method for removing an ozone organic solvent resist has been already provided, in which (1) and (2) act synergistically.
1-340817). Ozone acetic acid in which ozone is dissolved by about 300 ppm can be removed at several times the maximum stripping rate of ozone water, that is, at a rate of 5 to 6 μm / min.

Solvents such as acetic acid that are difficult to react with ozone are
Only the resist component dissolved in the solvent is decomposed by the ozone treatment, and the solvent is not affected. Therefore, if such a solvent is used as a resist removing agent, it can be repeatedly used, that is, it has a long life, and is desirable in terms of economical efficiency, resource saving, and environmental load. However, organic solvents that dissolve ozone well but do not react with ozone and dissolve polymers such as resist well are limited, and there are few problems regarding the environment and toxicity, and practicability is limited to acetic acid, propionic acid, and butyric acid. It is only a carboxylic acid having such a small molecular weight. On the other hand, the range of organic polymer materials in which the carboxylic acid has a particularly excellent solubility is not wide. For example, glacial acetic acid is suitable for dissolving resist materials such as novolac resin and cyclized polyisoprene, but other plastic films can only be applied to vinyl acetate resin, cellulose ester, etc. and are limited to a narrow range. . With respect to resists, new materials have appeared with the miniaturization of LSIs, and the ozone acetic acid treatment may reduce the stripping rate. Further, it is difficult to remove a resist whose surface has been hardened and altered by fine processing by reactive ion etching, by simply contacting it with an ozone acetic acid solution.

In addition, when the base of the organic coating is finely processed and the organic coating formed in the extremely narrow recess is to be removed, or the base is a material which is easily damaged by a low molecular weight carboxylic acid such as acetic acid. In this case, a treatment liquid obtained by adding ozone to a low-molecular-weight carboxylic acid at a high concentration has a problem that a sufficient removal effect may not be obtained due to insufficient wettability of the liquid or insufficient stripping rate.

[0007]

Therefore, an object of the present invention is to expand the range of the organic coating film which is the target of removal of the treatment liquid in which ozone gas is dissolved, and ozone is used for the resist film. A method of improving the peeling speed and wettability as compared with the case of using an added carboxylic acid, and an effective removing method similar to the case of the resist not only for the resist but also for the coating film, oil film, etc., and regeneration of the treatment liquid. It is intended to provide a method and an organic film removing agent.

[0008]

In order to solve the above-mentioned problems, firstly, the present invention provides a substrate having an ozone-decomposable organic coating on the surface thereof by contacting a treatment liquid in which ozone gas is dissolved with the organic coating. In the method of removing the above, the treatment liquid has a partition coefficient of (a) an organic substance which can dissolve the organic coating and is hardly decomposed by ozone, and (b) ozone in a gas at room temperature. The above is a solution with one or more kinds of organic solvents that are not easily decomposed by ozone (provided that at least one of the organic substance and / or the organic solvent is water-miscible). A method for removing a characteristic organic film is provided.

Secondly, the present invention relates to an organic film removing agent which is used by dissolving ozone gas in order to remove the organic film by bringing it into contact with a substrate having an ozone decomposing organic film on the surface. , (A) an organic substance that can dissolve the organic coating and is not easily decomposed by ozone, and (b) a partition coefficient with ozone in a gas of 0 at room temperature.
It is characterized by containing 6 or more and one or more kinds of organic solvents that are not easily decomposed by ozone (provided that at least one of the organic substances and / or the organic solvents is water-miscible). An organic film removing agent is provided.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. [Outline] The present invention is characterized by the composition of the treatment liquid used when removing the ozone-decomposable organic coating on the surface of the substrate. That is, the partition coefficient between the organic substance that can dissolve the ozone-decomposable organic film that is the component (a) and is not easily decomposed by ozone and the ozone in the gas that is the component (b) at room temperature The treatment liquid of the present invention, which is a solution mixed with an organic solvent that is 0.6 or more and is not easily decomposed by ozone, has the following characteristics, and by adopting the treatment liquid, the ability to remove various organic coatings is significantly increased. At the same time as improving, it is possible to utilize the unique performance of the component (a). 1. Since this treatment liquid has an excellent dissolving power for various ozone-decomposable organic coatings, the range of target organic coatings is wide. 2. Ozone dissolved in the treatment liquid decomposes the organic coating well. The decomposition reaction product generated by this decomposition has a low molecular weight, dissolves well in this treatment liquid, does not contaminate the substrate, and does not interfere with the removal performance in the subsequent treatment (regeneration treatment with ozone gas). To be. 3. Even if the concentration of ozone dissolved in this treatment agent becomes high, the treatment agent itself does not easily react with ozone and is not easily decomposed by ozone. 4. To be able to dissolve ozone in high concentration in this treatment agent in order to enhance the decomposition power by ozone. In particular, the above 1. This point was insufficient by the method for removing a resist or the like, which has been already provided by the present inventor by dissolving ozone in a low molecular weight carboxylic acid such as acetic acid.

[Component (a)] As the organic substance which can dissolve the ozone-decomposable organic coating which is the component (a) used in the present invention and is hardly decomposed by ozone, for example, a part of an ester compound is used. Tertiary alcohol; formula: C
Fatty acid represented by _n H _{2n + 1} COOH (wherein, n is an integer of 1 to 3); Formula: C _m H _{2m + 2} (wherein, m is an integer of 10 to 12)
A paraffinic saturated hydrocarbon represented by

Examples of the ester compound include alkylene carbonates such as ethylene carbonate and propylene carbonate, and acetic acid esters such as butyl acetate. In particular, ethylene carbonate and propylene carbonate are preferable because they have a high ability to dissolve various polymer compounds. Almost all alcohols are apt to react with ozone, but only the tertiary alcohol tert-butyl alcohol has a slow reaction, and therefore can be used in the present invention. Examples of the fatty acid include acetic acid, propionic acid, butyric acid and the like. The fatty acid can also be used as the component (b) described below. Examples of the above-mentioned paraffinic saturated hydrocarbon include decane and dodecane, which have a particularly large ability to dissolve in an oil film, but have a problem in terms of flammability, and therefore are used in combination with HFE described later.

[Component (b)] The organic solvent which is the component (b) used in the present invention, which has a partition coefficient with respect to ozone in the gas of 0.6 or more at room temperature and is hardly decomposed by ozone will be described. The distribution coefficient D with respect to ozone in the gas is C _L / C _G when the ozone concentration of the liquid saturated with the ozone concentration C _G [mg / L] is C _L [mg / L]
It shows the ratio of. A higher D value means a solvent that dissolves ozone better. In the present invention, a solvent having a D value of 0.6 or more, preferably 1.3 or more at room temperature is used.

Examples of the component (b) include compounds represented by the formula: C _n H
Fatty acid represented by _{2n + 1} COOH (wherein n is an integer of 1 to 3); at least one hydrofluoroether selected from the group consisting of C ₄ F ₉ OCH ₃ and C ₄ F ₉ OC ₂ H _5. (Hereinafter, it may be referred to as “HFE”) and the like. These may be used alone or in combination of two or more.

As the above-mentioned fatty acid, the same ones as exemplified for the component (a) can be mentioned. For example, the D value of acetic acid (purity: 97%) at 25 ℃ is 1.7, and the D value of propionic acid is
The value is 1.8, and the D value of butyric acid is 1.5. Also, 20%
By mixing a certain amount of water, while maintaining the necessary ozone dissolving power, it no longer falls under the Hazardous Substances of the Fire Service Act, so it is possible to remove organic coatings with a focus on safety. When water was mixed with acetic acid, the D value was about 0.
It is about 0.6 at 8, 70 wt% acetic acid.

Used as the above hydrofluoroether
C_FourF₉OCH₃(D value at 25 ℃ = 1.6 or more, boiling point 61
C, trade name: HFE-7100, 3M company) and C_FourF₉O
C₂H _Five(D value at 25 ℃ = 1.6 or more, boiling point 76 ℃, trade name: H
FE-7200, manufactured by 3M), the latter is
When using a mixed solvent with another solvent, another solvent that can be mixed
Wide range of agents. For example, dodecane is HFE-7200
Only can be mixed. In addition, hydrofluoroete
Has an ozone depletion potential of 0 and has a short atmospheric life,
There are no environmental problems like chlorine-based and Freon-based solvents
Suitable for use in the present invention.

[Composition of Treatment Liquid (Removing Agent)] The treatment liquid (removing agent) of the present invention is a mixed solution of the above-mentioned component (a) and component (b). Regarding the combination, the one used as the component (a) and the one used as the component (b) are not the same, and the component (a) and / or the component (b)
It is sufficient if at least one of the components is water-miscible,
There are no other special restrictions. The composition ratio of the component (a) and the component (b) varies depending on the type of each component and cannot be determined unconditionally, but at least the component (b) is used more (by weight ratio) than the component (a). That is, the (a) component / (b) component (weight ratio) is 0.1 / 99.9 or more, but less than 50/50.

Ultimately, most of the decomposition products derived from the organic film due to the oxidizing power of ozone are carboxylic acids such as glyoxylic acid, oxalic acid, formic acid and acetic acid, and water. These products are readily soluble in water-miscible treatment liquid components (which in the present invention means freely miscible with water). From this point of view, in order to make the decomposition liquid a uniform liquid phase,
It is optimal to use the above fatty acid as the component (a) or the component (b). Many of the above decomposition products are insoluble in hydrofluoroether. Therefore, when the component (b) contains hydrofluoroether, it must be used in combination with another water-miscible component such as fatty acid.

As the component (a), for example, when ethylene carbonate having a strong polarity is used, a mixed solution with a fatty acid is preferable. Although ethylene carbonate and the like are not dissolved in hydrofluoroether, they can be used as a mixed solvent of hydrofluoroether and the above-mentioned fatty acid as described above. The same applies when an ester compound other than alkylene carbonate is used. When, for example, tert-butyl alcohol is used as the component (a), it can be used in combination with hydrofluoroether because it is miscible with water. Further, for example, when a paraffinic saturated hydrocarbon such as decane is used, the component (b) to be combined with this must contain a fatty acid and the like.

[Ozone-decomposable organic coating] The organic coating which is the object of the removing method and the removing agent of the present invention is not only dissolved in the treatment liquid (removing agent), but is also sufficiently decomposed by ozone into a low molecular weight substance. It is a thing. In the oxidation mechanism of organic substances by ozone, the carbon-carbon double bond is usually the most reactive. The double bond of an olefinic compound is easily cleaved by a decomposition reaction called ozonolysis. Some aromatics have a slow decomposition rate, but generally, decomposition occurs due to cleavage or oxidation of side chains regardless of whether they are monocyclic or polycyclic. In addition, compounds having an oxygen-containing group other than the carboxyl group are easily decomposed. Among polymer compounds, those having a double bond in the monomer unit are decomposed extremely rapidly by ozone.

Therefore, cyclized polyisoprene, which is a typical negative resist material, decomposes very quickly, and the novolak resin, which has been the mainstream of positive resist materials, easily decomposes. The polyvinyl-phenol derivative, which is a chemically amplified positive resist material, is also slightly slow, but is sufficiently decomposed. As described above, the resist film is the most preferable organic film to be removed according to the present invention. Further, it is possible to effectively remove the resist film that has been cured by ion implantation.

With regard to fats and oils, a film of unsaturated fatty acid having a double bond in the molecule is the object of the present invention. Therefore, a coating film of an oil paint using a drying oil is suitable. In addition, since rosin for flux is a tricyclic terpene, it can be decomposed with ozone. In a synthetic resin coating, acrylic resin containing oxygen in the monomer unit, vinyl acetate resin enamel and the like can be decomposed by ozone, and thus the coating film is a target of the present invention.

[Organic film removal performance of treatment liquid (removing agent)]
In order to clearly show the improvement of the organic film removal performance of the treatment liquid (removing agent) obtained by mixing the component (a) and the component (b) of the present invention,
From the viewpoint of resist stripping speed, comparison is made with the conventional organic film removal method. For example, in the case of chemically amplified polyvinylphenol derivative resist, if ozone added acetic acid exhibits a peeling rate of 3 μm / min, adding ozone under the same conditions will add acetic acid / ethylene carbonate = 60/40 (weight ratio) as a treatment liquid (removal agent). In (), a peeling speed of 9 μm / min or more is obtained. In addition, ozone added acetic acid is 5μ against novolak type I-line resist.
When a peeling speed of m / min is shown, a peeling speed of 18 μm / min can be obtained by using the acetic acid / ethylene carbonate = 60/40 (weight ratio) treatment liquid (removing agent) instead of the ozone-added acetic acid. Since these have a strong dissolving effect on the resist even with a small amount of ethylene carbonate, the result is that the effect of the decrease in ozone concentration due to the decrease in acetic acid component is more than compensated (the stripping rate is tripled). This clearly shows the features of the present invention.

A treatment liquid (removal agent) obtained by mixing ethylene carbonate (1 to 3% by weight), acetic acid (10 to 20% by weight) and hydrofluoroether (the balance) is a novolak type I-line resist. On the other hand, almost the same peeling speed as that of acetic acid containing ozone was obtained, and the surface tension and the viscosity were almost the same as those of Freon-based detergents. Therefore,
It was possible to obtain a high stripping performance remover capable of removing even the resist adhering to the inner surface of the hole which was subjected to extremely fine processing. As described above, the treatment liquid (removing agent) that is a mixture can add not only sufficient resist stripping performance but also new special performance that cannot be exhibited by ozone-added acetic acid.

[Circulation and Reuse of Treatment Liquid] In the removal method of the present invention, the treatment liquid of the present invention itself has a feature that it hardly reacts with ozone, while the components derived from the organic film are converted to low molecular weight substances with ozone. It will be disassembled,
If the treatment liquid after the organic film removal treatment is transferred to another tank and ozone gas bubbling is performed, it is peeled from the substrate and transferred to the treatment liquid, and if decomposition treatment is added to components such as resist that have not been sufficiently decomposed This treatment liquid can be reused as a treatment liquid for removing another substrate. In the experiment, it was possible to reuse several tens of times. By this circulating use, the amount of chemical solution used can be reduced to 1/3 to 1/5 of the conventional method.

[0026]

EXAMPLES The organic film removing method and the removing agent according to the present invention will be described in more detail by the following examples, but the present invention is not limited to the following examples. The ozone gas used in the following examples has an ozone concentration of about 250 mg / L obtained by flowing 0.4% nitrogen-containing oxygen to the discharge type ozone generator at about 0.3-2 L / min. All the chemicals used were of reagent grade purity.

Further, from the road map by the American Semiconductor Industry Association, the organic carbon concentration on the surface after removing the organic film is 3.5 × 1.
If it is ¹³ atoms / cm ² or less, it is considered sufficient even in a 100 nm device. Therefore, a resist film or a coating film was formed using a 1000 Å oxide film wafer made of a Si wafer having a particularly low carbon content (1 × 10 ¹⁵ atoms / cm ³ or less) and used as a sample for evaluation of removal performance. After the removal process, JP 2000
By applying the sample preparation method described in JP-A-39410, the sample was housed in a holder for cyclotron irradiation, charged particle activation analysis was performed, and the absolute amount of residual surface organic carbon was determined.
Analysis is to quantify at ^{12 C (d, n) 13} N measured ¹³ N generated by the nuclear reaction of annihilation radiation chemical separation to beta ⁺ disintegrations. If the analysis result was 3.5 × 10 ¹³ atoms / cm ² or less, it was evaluated that the resist could be removed by stripping without particular notice, and the stripping rate was determined based on that. The reason why the Si wafer having a low carbon concentration is used as the resist coating sample is to keep the background in the analysis at 1 × 10 ¹² atoms / cm ² or less.

Example 1 When bubbling ozone gas into liquid ethylene carbonate, the degree of blue coloring peculiar to ozone gas was as pale as when bubbling with water, and it cannot be said that ethylene carbonate dissolves ozone well. I understand. However, as described later, the ethylene carbonate solution alone dissolves the resist well. Therefore, using a mixed solution of ethylene carbonate and acetic acid as a treatment liquid, ozone was added thereto to try to remove the chemically amplified resist film composed of the polyvinyl phenol derivative and the acid generator. The sample was coated with M20G (trade name, manufactured by JSR Corporation) with a film thickness of 0.8 μm at 140 ° C.
A wafer that has been baked for 90 seconds is cut into 2 cm × 2 cm chips.

The addition of ozone to the processing liquid is 100 mL in content.
Fill the quartz glass impinger with the above mixed solution at 25 ° C or single acetic acid, bubble ozone gas with a concentration of 250 mg / L for 5 minutes at a flow rate of 0.3 L / min, and immediately put the liquid into a quartz glass with an inner diameter of 2.2 cm. Transfer to a small beaker, immerse the wafer in the processing solution, perform resist removal processing on the sample chip, and if resist peeling is visually confirmed, rinse with acetic acid in another container for about 2 seconds and overflow. After transferring to a pure water tank and immersing for 3 minutes for thorough rinsing, it was air-dried in a clean bench with an activated carbon filter and stored in a holder for charged particle activation analysis.

FIG. 1 shows the relationship between the composition and the resist stripping rate when the mixing ratio (weight) of acetic acid / ethylene carbonate is 100/0, 80/20, 60/40, 40/60, and 20/80. Indicates. At room temperature, when ozone was added with acetic acid alone, the stripping rate of this chemically amplified resist was about 3 μm / min, which is about half that of the novolac resist. However, as the ratio of solute ethylene carbonate increases, the peeling speed increases, and the maximum peeling speed is obtained with a composition of acetic acid / ethylene carbonate = 60/40, and a value close to 10 μm / min is obtained, and the removal performance is significantly improved. Further, as the ethylene carbonate component increases, the peeling rate tends to decrease. Since ethylene carbonate has a melting point of 36 ° C., if it is heated to 40 ° C. and made into a liquid state, the resist film is dissolved at 6 μm / min without adding ozone to form a coloring liquid. That is, it has a great solubility in this resist. However, its solubility in ozone is small. On the other hand, acetic acid has a large solubility in ozone. In FIG. 1, the maximum part was formed in the composition of acetic acid / ethylene carbonate = 60/40 with respect to the peeling speed, as a result of the synergistic action of these two effects.

Example 2 A mixed removing solution having a composition of acetic acid / ethylene carbonate = 60/40 (weight ratio), which had the best peeling performance in Example 1, was heated to 40 ° C., ozone was added, and ion implantation was performed. The effect of removing the resist by the dipping treatment was examined for the wafer with the cured novolak-type resist film for I-line. This film has a thickness of 1.5 μm
X555 (trade name, manufactured by JSR Corporation) was baked at 130 ° C. for 300 seconds, and then B ⁺ was injected at 30 KeV at 1 × 10 ¹⁴ / cm ² . Since ethylene carbonate is slightly more likely to be decomposed by ozone than acetic acid, experimental equipment has been created so that the number of times the liquid can be reused repeatedly can be estimated when the mixed removal liquid is repeatedly regenerated with ozone and reused. In Figure 2,
A peeling tool row and a liquid supply tool row showing the concept are shown. Although this is a single-wafer experimental mechanism for the purpose of evaluation only, it can be applied to practical production by increasing the number of sheets to be processed in the dipping tank to make it into a batch system.

The stripping processing tank 1, the processing solution rinsing tank 2, and the ultrapure water rinsing tank 3 each have a 6 "wafer volume of 300 mL.
The wafer 4 is held in a quartz glass support (not shown) in a quartz glass square tank which is dipped in the substrate, and is manually dipped. In the tank 1, the processing liquid supply pipe 8 (hereinafter, the liquid piping is shown by a thick line in the figure) allows the processing liquid heated to 40 ° C. to flow from the tank 7 (initially filled with 600 mL of new processing liquid) to the pump P. It is supplied through the fine particle filter F and the liquid temperature is maintained at 40 ° C by the heater 9. There is a quartz glass ozone diffuser 10 on the heater, and 0.5 L / min from an ozone generator (not shown) to a pipe 11 (hereinafter, gas pipe is shown by a thick dotted line) and a valve 12. Bubbling is performed by sending ozone gas at a flow rate. After the immersion treatment for 5 minutes, the wafer is transferred to the rinse tank 2. 6
When the processing for one sheet is completed, 50m with the valve 13 and the piping 14.
L is discharged to the tank 6, 50 mL of the tank 7 is replenished, and after 1 minute, the removal process for 6 wafers is similarly performed. In this way, the discharge of liquid, the replenishment, and the processing of 6 wafers are repeated.

The rinse tank 2 has exactly the same structure as the treatment tank 1, and at the time of filling the liquid in the initial tank 1, the rinse liquid heated to 40 ° C. at the same time is supplied from the tank 5 equipped with the heater 15 to the pump P and the fine particle filter. Rinsing liquid supply pipe 16 via F
Filled with. Ozone gas bubbling is started at the same time as the tank 1, and when the wafer after the removal processing is dipped, it is rinsed for a predetermined time. Every time the rinsing process for 6 sheets is completed, 15 mL is discharged to the tank 6 through the valve 17 and the pipe 18, and 15 mL is replenished from the tank 5. The wafer after the ozone bubbling rinse was subjected to an overflow rinse (mechanism not shown) with ultrapure water at room temperature in the tank 3 and dried by a spin dryer (not shown).

When the immersion time in each tank was 2 minutes, immediately after drying, no residual resist was visually observed, and the surface adhesion of undecomposed cured resist fine pieces was examined by a microscope, but was not observed. . Further, a chip was cut out from the wafer that was first processed to obtain a sample for charged particle activation analysis. The amount of residual organic carbon on the surface is 2.7 × 10 ¹³ atoms /
At cm ² , the cured resist could be sufficiently removed.

Although the resist film is peeled off by the treatment in the tank 1, undecomposed cured resist fine particles float in the liquid. In order to fully decompose this fine piece of effluent in the tank 6,
When the liquid amount reaches 100 mL, ozone gas is bubbled through the gas divergent 22 at a flow rate of 1 L / min through the valves 19 and 20 and the gas pipe 21. After 5 minutes have passed since the liquid volume has reached 200 mL, high-purity nitrogen gas pipe 23, valve 24
Nitrogen gas is bubbled for 5 minutes from the diffuser 22 via the valve 20 and the dissolved ozone is degassed from the liquid in the tank.
Then, the solution is transferred to the tank 7. The tanks 6 and 7 are equipped with heaters 27 and 28, and the temperature of the liquid inside is about 40 ° C.
Hold on. The tanks 5 and 7 are the new processing liquid introduction pipe 2
9 and a valve 30 attached to it, and liquid is discarded by a waste pipe 31 and an attached valve 32.

In the liquid supply instrument system, the cured resist fine particles which could not be decomposed by ozone were cured at 1 × 10 ¹⁴ / cm ²
However, the amount of the ion implantation is extremely small and does not impose a heavy burden on the filter attached to the processing liquid supply pipe 8. Therefore, if the performance of the processing liquid is deteriorated, it is considered that the deterioration of the stripping performance is caused by the increase of reaction products of the resist and the processing liquid itself with ozone. Therefore, following the treatment of the first 6 wafers, the above circulating liquid supply was performed 6 times × 19 times, that is, 114 wafers were performed on the wafer of the resist film that had not been ion-implanted, and the last one was ion-implanted sample wafer. Done by. Immediately after the drying, the resist removal state was evaluated in the same manner as the original sample, and the cured resist was evaluated by visual observation of the surface and evaluation of the charged particle activation analysis result (residual carbon amount: 3.4 × 10 ¹³ atoms / cm ² ). It was confirmed that the ability to remove the film was not different from the original liquid.

Treatment liquid used for 120 sheets is 1.2L
Thus, 100 sheets can be processed per liter. In the conventional method, 300 mL is usually used for every 6 sheets, so 20 sheets are processed per 1 L. With this mixed solution, the life of the solution can be made five times longer than that of the conventional method by the resist decomposition by ozone. This is because ethylene carbonate, like acetic acid, is less susceptible to decomposition by ozone.

Example 3 In the treatment for removing the organic coating on the surface having fine gaps, the coating adhered to the side surface or the bottom in the gap may remain unremoved, and therefore it is necessary to add a precise removal treatment. Becomes Super L
Due to the miniaturization of SI, an altered film derived from the resist is formed on the side wall of the fine hole due to the high aspect ratio dry etching. The masked resist is generally removed by oxygen plasma ashing, but since this deteriorated film remains, wet removal with a stripping solution follows. As miniaturization progresses, a resist removing solution having a surface tension and a viscosity coefficient as small as possible is required for the treatment in the fine holes. Therefore, HFE-7100 was used as a solvent for dissolving ozone well, and its resist stripping action was examined as a mixed solution with acetic acid.

The film to be removed is IX500 having a thickness of 1.5 μm.
(Trade name, manufactured by JSR Corporation) is baked at 140 ° C. for 60 seconds. The single-wafer experimental system is the removal treatment tank 1 of the second embodiment.
And a small HFE vapor drying tank (not shown) containing the HFE solution. The wafer was held by the support of the same example and processed in each tank in order. The tank 1 and the tank 2 were filled with the mixed solution and heated to 40 ° C., and ozone gas was bubbled in the tank 1 only in the same manner as in Example 2. The mixing ratio (weight) of the treatment liquid is HFE / acetic acid = 90/1
When 0, 80/20, and 60/40 were examined, they could not be removed even by dipping for 2 minutes at a mixing ratio of 90/10. When the mixing ratio was 80/20, it took 1 minute to remove it when visually confirmed. After rinsing in the tank 2 for 1 minute, it was dried with HFE-7100 vapor and the removed surface was observed with a microscope, but there was no peeling residue at all. When the mixing ratio was 60/40, the time required for removal in tank 1 was 45 seconds, and the peeling rate was about 2 μm / min, so a removal performance that was adequate for this type of removal purpose was obtained. The surface tension and viscosity are 16 dyn / cm and 0.6 cP at a mixing ratio of 80/20.
And the mixing ratio of 60/40 is 18 dyn / cm and
0.7 cP, 27 dyn / c in case of ozone acetic acid treatment
Compared with m and 1.0 cP, the wettability to the minute gap was significantly improved.

Example 4 In Example 3, a resist removing solution having a small surface tension and a low viscosity was shown, but ethylene carbonate (concentration 1% by weight), HFE-7200 and acetic acid were mixed so that the stripping rate could be satisfied. The same resist removal experiment as in Example 3 was conducted using a mixed solution composed of a mixed solution. The liquid in the steam drying tank is HFE-720.
It is 0. Even when HFE / acetic acid = 90/10 (weight ratio), a peeling rate of 3 μm / min was obtained, and in this case, the surface tension and viscosity of the treatment liquid were almost the same as those of HFE. Mixing ratio 80/20
The stripping rate is 4.5 μm / min, which is very close to the stripping rate of ozone-added acetic acid.

Example 5 A fluorine-based cleaning agent having a small surface tension and a low viscosity was most effective for precision cleaning of parts having a complicated surface shape.
Therefore, using a mixed solution of tert-butyl alcohol (concentration: 10% by weight), which has relatively little reaction with ozone, and a HFE-7100 solvent, the removal effect and the regeneration effect of the organic film removing solution by ozone of the present invention were investigated. It was It is known that a fluorine-based cleaning agent to which alcohol is added dissolves rosin-based flux. This flux was used as a removal target and was applied on the oxidized wafer used in each example to obtain a removal sample. The experimental tool used in Example 3 was used, and after 1 minute of ozone bubbling removal treatment, a series of treatments were performed in the same manner as in Example 3. Although the flux was visually removed,
Further removal was confirmed by charged particle activation analysis. 20 in tank 1
After processing one sheet, no color change due to flux dissolution was observed in the liquid in the tank, and it is considered that the flux was decomposed.

Fluorine-based cleaning agents that have solved environmental problems are more expensive than other solvents, but if the dissolved organic film is decomposed by ozone and the life of the cleaning agent is extended, the economic difficulties are alleviated. It is possible to expand the application field of film removal that takes advantage of the characteristics of fluorine. Therefore, a polyvinyl butyral coating film on a copper plate was prepared in the same manner as in Example 3 with a mixture of HFE-7200 70% by weight, acetic acid 20% by weight, and butyl acetate 10% by weight.
With the experimental equipment of No. 3, each treatment time was set to 5 minutes, and peeling of the coating film was tried. The film removal was visually confirmed. The same treatment was applied to a vinyl chloride resin plate-shaped sample in which an oil film of the drying oil remained, to try to remove the oil film. The composition of the treatment liquid is HFE
-7200 70% by weight, acetic acid 20% by weight, decane 10% by weight. Although each treatment time was set to 2 minutes, no coating remained visually, and the blue coloring state of the liquid derived from dissolved ozone was recovered after the treatment time had elapsed.

Example 6 Using the stripping treatment tank 1 and ozone spreader 10 of Example 2, this tank was set right above a vibrator in a water tank containing a 28KC ultrasonic vibrator of a throw-in type. Then, the removal of the coating film was examined. The target of peeling is a polymethylmethacrylate coating film and a polyvinyl acetate coating film on a 10 cm square stainless steel plate.
The composition of the treatment liquid is a mixed solution of 70% by weight of propionic acid and 30% by weight of butyl acetate. The treatment was carried out at 20 ° C.
Ozone was bubbled in the same manner as in Example 2, and the sample was immersed after 5 minutes had passed, and the ultrasonic wave was stopped for 30 seconds and repeated for 10 seconds. Although the thickness of the coating film was not measured, peeling was visually confirmed in about 5 minutes in the case of the polymethylmethacrylate coating film and in about 3 minutes in the case of the polyvinyl acetate coating film.

[0044]

INDUSTRIAL APPLICABILITY According to the present invention, a treatment liquid having an excellent dissolving power for an organic coating film made of a specific mixed solution is used, and ozone is dissolved therein to remove the organic coating film. It has become possible to remove the ozone-decomposable organic coating. Further, since the treatment liquid itself does not easily react with ozone, it is possible to dissolve ozone in a high concentration in the treatment liquid in order to enhance the decomposition power of ozone, and further, the reaction product after decomposition has a low molecular weight. However, the components derived from the organic coating dissolved in the treatment liquid well without polluting the substrate and dissolved in the treatment liquid after the removal treatment are treated with ozone gas in an area different from the treatment area. Since the treatment liquid can be decomposed and the treatment liquid can be regenerated and reused, the removal performance of the organic film can be significantly improved, at the same time, there is no problem in terms of environment and resource saving can be achieved.

[Brief description of drawings]

FIG. 1 is a diagram showing a correlation between a composition ratio of acetic acid: ethylene carbonate and a resist stripping rate obtained in Example 1.

FIG. 2 is a diagram showing an outline of a stripping instrument row and a liquid supply instrument row for a single-wafer experiment mechanism used in Example 2.

[Explanation of symbols]

1. Peeling treatment tank 2. Treatment liquid rinse tank 3. Ultrapure water rinse tank 4. Wafer 5, 6, 7. Tank 8. Processing liquid supply pipe 9. Heater 10. Ozone diffuser 11. Piping 12,13. Valve 14. Piping 15. Heater 16. Rinse liquid supply pipe 17. Valve 18. Piping 19,20. Valve 21. Gas piping 22. Divergence device 23. Nitrogen gas piping 25. Connection pipe 26. Valve 27, 28. Heater 29. New treatment liquid introduction pipe 30. Valve 31. Waste pipe 32. valve

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 21/027 H01L 21/30 572B (72) Inventor Hisashi Muraoka 735, Shinba-cho, Kohoku-ku, Yokohama-shi, Kanagawa Formula company Purelex F term (reference) 2H096 AA25 AA27 LA03 4H003 DA15 DB01 EA31 EB07 EB09 ED03 ED26 ED32 5F046 MA02 MA05

Claims (13)

[Claims] 1. A method of removing a treatment liquid in which ozone gas is dissolved by contacting a substrate having an ozone-decomposable organic coating on the surface thereof to remove the organic coating, wherein the treatment liquid dissolves (a) the organic coating. Organic compounds of one or a mixture of two or more, which have a partition coefficient of 0.6 or more at room temperature and which are difficult to decompose by ozone and (b) ozone in gas. A method of removing an organic film, which is a solution with a solvent (however, at least one of the organic substance and / or the organic solvent is miscible with water). 2. The organic substance of (a) is an ester compound, and the organic solvent of (b) is of the formula: C _n H _{2n + 1} COOH.
(Wherein n is an integer of 1 to 3), or the fatty acid and C ₄ F ₉ OCH ₃ and C ₄ F ₉ OC ₂ H ₅
The method according to claim 1, which is a mixture with at least one hydrofluoroether selected from the group consisting of: 3. The method according to claim 2, wherein the ester compound is at least one ester compound selected from the group consisting of alkylene carbonate and alkyl acetate. 4. The organic substance of (a) is tert-butyl alcohol, and the organic solvent of (b) is C ₄ F ₉ OCH ₃
And at least one hydrofluoroether selected from the group consisting of C ₄ F ₉ OC ₂ H ₅ and the method according to claim 1. 5. The organic material of (a) has the formula: C _n H _{2n + 1} COO.
A fatty acid represented by H (wherein n is an integer of 1 to 3), and the organic solvent (b) is from the group consisting of C ₄ F ₉ OCH ₃ and C ₄ F ₉ OC ₂ H _5. The method according to claim 1, which is at least one hydrofluoroether selected. 6. The method according to any one of claims 1 to 5, wherein the treatment liquid after the organic film removal treatment is transferred to an area different from the area where the treatment is applied and treated with ozone gas. After that, the method is characterized by returning to the area where the treatment is applied and reusing it as a treatment liquid for treating another substrate. 7. The method according to claim 1, wherein the organic coating film is a resist film. 8. An organic film removing agent which is used by dissolving ozone gas in order to bring the substrate into contact with a substrate having an ozone decomposable organic film to remove the organic film,
(a) an organic substance that can dissolve the organic coating and that is not easily decomposed by ozone, and (b) a partition coefficient with ozone in gas that is 0.6 or more at room temperature and is not easily decomposed by ozone An organic film removing agent comprising one or a mixture of two or more organic solvents (provided that at least one of the organic substance and / or the organic solvent is water-miscible). 9. The organic substance of (a) is an ester compound, and the organic solvent of (b) is of the formula: C _n H _{2n + 1} COOH.
(Wherein n is an integer of 1 to 3), or the fatty acid and C ₄ F ₉ OCH ₃ and C ₄ F ₉ OC ₂ H ₅
The organic film removing agent according to claim 8, which is a mixture with at least one hydrofluoroether selected from the group consisting of: 10. The at least one ester compound is selected from the group consisting of alkylene carbonate and alkyl acetate.
The organic film removing agent according to claim 8, which is a kind of ester compound. 11. The organic substance of (a) is tert-butyl alcohol, and the organic solvent of (b) is C ₄ F ₉ OCH.
The organic film remover according to claim 8, which is at least one member selected from the group consisting of ₃ and C ₄ F ₉ OC ₂ H ₅ . 12. The organic substance of (a) above has the formula: C _n H _{2n + 1} CO
A fatty acid represented by OH (wherein n is an integer of 1 to 3), and the organic solvent (b) is a group consisting of C ₄ F ₉ OCH ₃ and C ₄ F ₉ OC ₂ H _5. The organic film removing agent according to claim 8, which is at least one kind of hydrofluoroether selected. 13. The method according to claim 8, which is for removing a resist film.
The organic film removing agent according to any one of 1.