JP4004318B2 - Method and agent for removing organic coating - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for removing an organic film adhering to a substrate for cleaning the surface of an electronic device substrate or the like. Specifically, the present invention relates to removal of a photoresist film used for processing a semiconductor wafer or a liquid crystal substrate, and removal of an organic contamination film on the substrate. Furthermore, the present invention can be applied to the removal of a general organic film such as an oil film or a coating film on a substrate.
[0002]
[Prior art]
Removal of photoresist used for microfabrication of oxide and polysilicon films is usually done with a mixture of sulfuric acid (3 or 4 volumes): hydrogen peroxide (1 volume) (called piranha) with 11O A method of heating to ˜140 ° C. and immersing for 10 minutes for 20 minutes is widely used. In piranha treatment, the resist is decomposed and can be processed repeatedly in the same solution. However, hydrogen peroxide decomposes rapidly into water, and concentrated sulfuric acid is highly hygroscopic. As a result, the peeling ability is reduced, and it can be repeatedly used only about ten times. An apparatus that distills diluted waste liquid to a high concentration and recycles has also appeared, but there is a problem with economic efficiency, and sulfuric acid is the most used chemical in the semiconductor industry. Furthermore, since it is subjected to high-temperature treatment, acid gas is often discharged, and both exhaust and drainage have a great impact on the environment.
[0003]
In the case of wiring metal film processing, the resist is removed by heat treatment with an organic solvent such as n-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO) or amines. Since these chemicals simply dissolve the resist and do not decompose it, if the same solution is used repeatedly, the concentration of the dissolved component increases rapidly, and can only be used about 5 to 6 times. In addition, 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. Accordingly, the required amount of organic solvent is further increased. Therefore, not only is it difficult to take measures against exhaust and drainage, but organic solvents are generally expensive, so there is a problem in terms of economy.
[0004]
Therefore, recently, an environment-friendly resist removal using a gas containing high-concentration ozone (hereinafter referred to as ozone gas) and water has been attempted. However, in such ozone water treatment, in the case of an I-line novolak resin-based positive resist film widely used in LSI manufacturing, the stripping rate is about 1 μm / min, and there is no margin for stripping capability, so the application is limited. The
In order to drastically solve the slow removal rate of ozone water treatment, the present inventor uses an organic solvent having a high ability to dissolve ozone, for example, acetic acid. Has already provided a method for removing an ozone organic solvent resist that synergistically acts (Japanese Patent Laid-Open No. 2001-340817). Ozone acetic acid in which about 300 ppm of ozone is dissolved with respect to the I-line novolak resin-based resist can be removed several times the maximum stripping rate of ozone water, that is, 5 to 6 μm / min.
[0005]
For a solvent that does not easily react with ozone, such as acetic acid, only the resist component dissolved in the solvent is decomposed by the ozone treatment, and the solvent is not affected. Therefore, when such a solvent is used as a resist remover, it can be used repeatedly, that is, it has a long life, and is desirable in terms of economy, saving resources, and environmental load.
However, organic solvents that dissolve ozone well but do not react with ozone and dissolve polymers such as resist are limited, and there are few problems regarding the environment and toxicity, and there are practicality of acetic acid, propionic acid and butyric acid. Only such low molecular weight carboxylic acids. On the other hand, the range of the organic polymer material in which the carboxylic acid exhibits particularly excellent solubility is not wide. For example, glacial acetic acid is suitable for dissolving resist materials such as novolak 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. . Even in resists, new materials have appeared along with the ultra-miniaturization of LSIs, and the stripping rate may be reduced by ozone acetic acid treatment. Further, it is difficult to remove a resist whose surface has been hardened and changed by reactive ion etching by simple contact with an ozone acetic acid solution.
[0006]
Moreover, when the base of the organic coating is finely processed and it is intended to remove the organic coating generated in a very narrow recess, or when the base is a material that is easily damaged by a low molecular weight carboxylic acid such as acetic acid. However, a treatment liquid in which ozone is added at a high concentration to a low molecular weight carboxylic acid has a problem that a satisfactory removal effect may not be obtained due to insufficient wettability of the liquid or insufficient peeling speed.
[0007]
[Problems to be solved by the invention]
Therefore, an object of the present invention is to increase the range of the organic film that is a target for removal of the treatment liquid in which ozone gas is dissolved, and the resist film is peeled more than when ozone-added carboxylic acid is used. A method for improving speed and wettability, as well as a resist, an effective removal method similar to the case of a resist, a coating solution, an oil film, etc. The purpose is to provide an agent.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the present invention firstly
In the method of removing the organic coating by contacting a substrate having an ozone-decomposable organic coating on the surface with a processing solution in which ozone gas is dissolved, the processing solution can (a) dissolve the organic coating, And (b) a solution of one or more organic solvents that have a partition coefficient of 0.6 or more at room temperature and that are difficult to be decomposed by ozone and that are difficult to be decomposed by ozone. However, at least one of the organic substance and / or the organic solvent is miscible with water) Dissolved ozone in A method for removing an organic film is provided.
[0009]
In addition, the present invention secondly,
An organic coating remover used by dissolving ozone gas to remove the organic coating by contacting with a substrate having an ozone decomposable organic coating on the surface, wherein (a) the organic coating can be dissolved And an organic substance that is difficult to be decomposed by ozone, and (b) one or more organic solvents that have a partition coefficient of 0.6 or more at room temperature and that are difficult to be decomposed by ozone. (However, at least one of the organic substance and / or the organic solvent is miscible with water) (Hereafter, abbreviated as “removing agent”) I will provide a.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
[Overview]
The present invention is characterized by the composition of the treatment liquid used when removing the ozone decomposable organic coating on the substrate surface. That is, the partition coefficient between the organic substance that can dissolve the ozone-decomposable organic film as the component (a) and is difficult to be decomposed by ozone and the ozone in the gas as the component (b) is room temperature. A solution mixed with an organic solvent that is 0.6 or more and is not easily decomposed by ozone. (Ie remover) with ozone dissolved The treatment liquid of the present invention has the following characteristics, and by adopting the treatment liquid, the ability to remove various organic coatings can be remarkably improved, and at the same time, the characteristic performance of the component (a) can be utilized. it can.
1. Since this treatment solution has an excellent dissolving power for various ozone-decomposable organic coatings, the target organic coating has a wide range.
2. The ozone dissolved in the treatment solution should decompose the organic coating well. The decomposition reaction product produced by this decomposition is of low molecular weight, (1) It dissolves well in this treatment solution, (2) Without contaminating the substrate (3) The removal process should not interfere with the subsequent treatment (regeneration treatment with ozone gas).
3. Book Removal Even if the ozone dissolved in the agent becomes high concentration Removal The agent itself does not react easily with ozone and is not easily decomposed by ozone.
4). In order to increase the decomposition power by ozone, Removal It must be able to dissolve ozone in the agent at a high concentration.
In particular, the above 1. This point was insufficient by the method for removing a resist or the like which was performed by dissolving ozone in a low molecular weight carboxylic acid such as acetic acid already provided by the present inventors.
[0011]
[(A) component]
Examples of organic substances that can dissolve the ozone-decomposable organic coating (a) component used in the present invention and are not easily decomposed by ozone include, for example, a part of ester compounds; tertiary alcohols; _n H _{2n + 1} Fatty acid represented by COOH (where n is an integer of 1 to 3); Formula: C _m H _{2m + 2} Paraffinic saturated hydrocarbons represented by the formula (wherein m is an integer of 10 to 12) can be exemplified.
[0012]
Examples of the ester compound include alkylene carbonates such as ethylene carbonate and propylene carbonate, and acetate esters such as butyl acetate. In particular, ethylene carbonate and propylene carbonate are preferable because they have a high solubility for various polymer compounds. Almost all alcohols easily react with ozone, but only the tertiary alcohol tert-butyl alcohol reacts slowly and 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 a component (b) described later. Examples of the paraffinic saturated hydrocarbon include decane, dodecane, and the like, and these have a particularly high ability to dissolve in an oil film, but have a problem in terms of flammability, and are used in combination with HFE described later.
[0013]
[Component (b)]
The organic solvent which has a partition coefficient of 0.6 or more at room temperature with ozone as the component (b) used in the present invention and is hardly decomposed by ozone will be described.
The distribution coefficient D with ozone in the gas is the ozone concentration C _G The ozone concentration of the liquid saturated with [mg / L] ozone gas is C _L C when [mg / L] _L / C _G The ratio is shown. 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.
[0014]
Examples of the component (b) include the formula: C _n H _{2n + 1} Fatty acid represented by COOH (wherein n is an integer of 1 to 3); C _Four F ₉ OCH ₃ And C _Four F ₉ OC ₂ H _Five And at least one hydrofluoroether selected from the group consisting of (hereinafter sometimes referred to as “HFE”) and the like. These may be used alone or in combination of two or more.
[0015]
Examples of the fatty acid include those exemplified for the component (a). For example, the D value of acetic acid (purity: 97%) at 25 ° C. is 1.7, the D value of propionic acid is 1.8, and the D value of butyric acid is 1.5. In addition, when about 20% of water is mixed, while maintaining the required ozone dissolving power, it is no longer a hazardous material under the Fire Service Act, so it is possible to remove the organic film with an emphasis on safety. When water is mixed with acetic acid, the D value is about 0.8 for 80% by weight acetic acid and about 0.6 for 70% by weight acetic acid.
[0016]
C used as the hydrofluoroether _Four F ₉ OCH _Three (D value at 25 ° C. = 1.6 or more, boiling point 61 ° C., trade name: HFE-7100, manufactured by 3M Company) and C _Four F ₉ OC ₂ H _Five (The D value at 25 ° C. = 1.6 or more, the boiling point 76 ° C., trade name: HFE-7200, manufactured by 3M Company), the latter can be mixed when other solvents are used as mixed solvents A wide range of solvents. For example, dodecane can only be mixed with HFE-7200. Hydrofluoroether is suitable for use in the present invention because it has an ozone depletion coefficient of 0, has a short atmospheric life, and does not have environmental problems such as chlorine and freon solvents.
[0017]
[Removal agent composition]
The present invention Remover A mixed solution of the component (a) and the component (b). Regarding the combination, those used as the component (a) are not the same as those used as the component (b), and at least one of the component (a) and / or the component (b) is water. There is no particular limitation as long as it is miscible.
The composition ratio of the component (a) and the component (b) varies depending on the type of each component and is not generally determined, but at least the component (b) is used more than the component (a) (by weight). That is, (a) component / (b) component (weight ratio) is 0.1 / 99.9 or more, but smaller than 50/50.
[0018]
The decomposition products derived from the organic film by the oxidizing power of ozone are finally mostly carboxylic acids such as glyoxylic acid, oxalic acid, formic acid, acetic acid, and water. These products are easily soluble in water miscible processing solution components (meaning those that are freely mixed with water in the present invention). From this point of view, it is optimal to use the fatty acid as the component (a) or (b) in order to make the decomposition solution into a uniform liquid phase.
Many of the decomposition products are insoluble in hydrofluoroether. Therefore, when the component (b) contains a hydrofluoroether, it is necessary to use it together with other water-miscible components such as fatty acids.
[0019]
For example, when ethylene carbonate having a strong polarity is used as the component (a), a mixed solution with a fatty acid is preferable. Ethylene carbonate or the like does not dissolve in the hydrofluoroether, but can be used as a mixed solvent of the hydrofluoroether and the fatty acid as described above. The same applies when an ester compound other than alkylene carbonate is used.
For example, when tert-butyl alcohol is used as the component (a), it can be used in combination with hydrofluoroether because it is miscible with water. For example, when using paraffin type saturated hydrocarbons such as decane, the component (b) to be combined with this must contain a fatty acid or the like.
[0020]
[Ozone-degrading organic coating]
The organic film that is the target of the removal method and the removal agent of the present invention is simply a treatment liquid ( Or In addition to being dissolved in the removal agent, it is sufficiently decomposed into low molecular weight substances by ozone.
In the mechanism of organic matter oxidation by ozone, carbon-carbon double bonds are usually the most reactive. The double bond of an olefin compound is easily cleaved by a decomposition reaction called ozonolysis. Some aromatics have a slow decomposition rate, but in general, decomposition occurs by cleavage or oxidation of side chains regardless of whether they are monocyclic or polycyclic. In addition, a compound having a group containing oxygen except for a carboxyl group is easily decomposed. Among polymer compounds, those having a double bond in the monomer unit are decomposed extremely rapidly by ozone.
[0021]
Therefore, the cyclized polyisoprene of a typical negative resist material decomposes very quickly, and the novolak resin that has been the mainstream of the positive resist material easily decomposes. Chemically amplified positive resist materials such as polyvinyl-phenol derivatives are also slightly slow, but they decompose sufficiently. Thus, the resist film is most preferable as the organic film to be removed in the present invention. Further, it is possible to effectively remove the resist film cured by ion implantation.
[0022]
In the case of fats and oils, a film of unsaturated fatty acid having a double bond in the molecule is an object of the present invention. Therefore, an oil-based paint film using a drying oil is suitable. Moreover, since the rosin for flux is a tricyclic terpene, it can be decomposed with ozone. In the synthetic resin-based paint, the acrylic resin-based resin containing oxygen in the monomer unit, the vinyl acetate resin enamel, and the like can be decomposed by ozone, so that the coating film is an object of removal of the present invention.
[0023]
[ Treatment liquid Organic film removal performance]
The above component (a) and component (b) of the present invention are mixed. Remover In order to clearly show the improvement of the organic film removal performance, it is compared with the conventional organic film removal method from the viewpoint of the resist peeling speed. For example, in a chemically amplified polyvinylphenol derivative resist, when ozone-added acetic acid shows a stripping rate of 3 μm / min, acetic acid / ethylene carbonate = 60/40 (weight ratio) when ozone is added under the same conditions With treatment liquid Can obtain a peeling rate of 9 μm / min or more. Further, when the ozone-added acetic acid exhibits a peeling rate of 5 μm / min with respect to the novolak type I-line resist, the ozone-added acetic acid is replaced with the ozone-added acetic acid. Added ozone Acetic acid / ethylene carbonate = 60/40 (weight ratio) Treatment liquid When used, a peel rate of 18 μm / min is obtained. Since these have a strong dissolving action on the resist even with a small amount of ethylene carbonate, they are more than compensated for the decrease in ozone concentration due to the decrease in the acetic acid component (tripping rate is tripled). This clearly shows the features of the present invention.
[0024]
Also, ethylene carbonate (1 to 3% by weight), acetic acid (10 to 20% by weight) and hydrofluoroether (remainder) were mixed. The treatment liquid added with ozone With respect to the novolak type I-line resist, a peeling rate almost the same as that of ozone-added acetic acid was obtained, and the surface tension and viscosity were almost the same as those of the freon cleaning agent. Therefore, high peeling performance that can remove even the resist adhering to the inner surface of the hole which has been processed extremely finely processing An agent was obtained. Like this is a mixture Treatment liquid In addition to sufficient resist stripping performance, it is possible to add new special performance that cannot be achieved with ozone-added acetic acid.
[0025]
[Use of recycled processing solution]
In the removal method of the present invention, Remover In itself, there is a feature that it hardly reacts with ozone. On the other hand, components derived from organic coating are decomposed into low molecular weight components by ozone, so the processing liquid after organic coating removal processing is transferred to another tank and ozone gas bubbling is performed. If the substrate is peeled off from the substrate and transferred to the treatment liquid, and a decomposition treatment is added to a component such as a resist that is still insufficiently decomposed, the treatment liquid can be reused as a removal treatment liquid for another substrate. In the experiment, it could be reused several tens of times. By this circulation use, the amount of the chemical used can be reduced from 1/3 to 1/5 of the conventional method.
[0026]
【Example】
The organic film removing method and the removing agent according to the present invention will be described in more detail with reference to 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 0.3% to 2 L / min of oxygen containing 0.4% nitrogen in a discharge type ozone generator. The chemicals used are of reagent-grade purity.
[0027]
Also, from the road map by the American Semiconductor Industry Association, the organic carbon concentration on the surface after removing the organic coating is 3.5 x 10 ¹³ Atom / cm ² The following is considered sufficient for a 100 nm device. Therefore, especially Si wafers with low carbon (1 × 10 ¹⁵ Atom / cm ^Three Using the 1000 Å oxide film wafer prepared in the following, a resist film or a coating film was formed and used as a sample for removal performance evaluation. After the removal treatment, the sample preparation method described in JP-A-2000-39410 is applied, and the sample is stored in a cyclotron irradiation holder, charged particle activation analysis is performed, and the absolute amount of remaining surface organic carbon is obtained. It was.
The analytical method is ¹² C (d, n) ¹³ Produced by N nuclear reaction ¹³ Chemical separation of N and β ⁺ It is quantified by measuring the annihilation radiation of decay. The analysis result is 3.5 × 10 above ¹³ Atom / cm ² Below, it was evaluated that the resist could be removed without any particular notice, and the removal rate was determined based on that. The reason for using a low-carbon Si wafer as the resist coating sample is that the analysis background is 1 × 10 ¹² Atom / cm ² This is to make the following.
[0028]
Example 1
When ozone gas is bubbled into liquid ethylene carbonate, the degree of blue coloring peculiar to ozone gas is as light as in the case of bubbling with water, and it can be seen that ethylene carbonate does not dissolve ozone well. However, as will be described later, the ethylene carbonate solution alone can dissolve the resist well. Therefore, mixed solution of ethylene carbonate and acetic acid Remover In this case, ozone was added thereto, and an attempt was made to remove a chemically amplified resist film composed of a polyvinyl / phenol derivative and an acid generator. The sample was obtained by cutting a wafer coated with M20G (trade name, manufactured by JSR Corporation) with a thickness of 0.8 μm and baked at 140 ° C. for 90 seconds into 2 cm × 2 cm chips.
[0029]
Remover Ozone was added to the impregnated 100 mL quartz glass impinger filled with the above mixed solution at 25 ° C or single acetic acid, and ozone gas with a concentration of 250 mg / L was bubbled for 5 minutes at a flow rate of 0.3 L / min. Immediately transfer the solution to a small 2.2 cm internal quartz glass beaker, immerse the wafer in the processing solution, perform resist removal processing on the sample chip, and visually confirm resist removal, use acetic acid in another container. After rinsing for about 2 seconds and transferring to an ultrapure water tank that overflowed and immersed for 3 minutes and thoroughly rinsed, it was air-dried in a clean bench equipped with an activated carbon filter and stored in a holder for charged particle activation analysis.
[0030]
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.
At room temperature, when ozone was added with acetic acid alone, this chemically amplified resist had a peeling rate of about 3 μm / min, which is about half that of the novolak resist. However, as the ratio of ethylene carbonate in the solute increases, the peeling rate increases, and the maximum peeling rate is obtained with a composition of acetic acid / ethylene carbonate = 60/40. A value close to 10 μm / min is obtained, and the removal performance is remarkably improved. Furthermore, as the ethylene carbonate component increases, the peeling rate tends to decrease. Since ethylene carbonate has a melting point of 36 ° C., when heated to 40 ° C. to form a liquid, the resist film is dissolved at 6 μm / min even when ozone is not added to form a colored liquid. That is, it has a large solubility in this resist. However, its ability to dissolve ozone is small. On the other hand, acetic acid has a large solubility in ozone. In FIG. 1, the maximum portion was formed with the composition of acetic acid / ethylene carbonate = 60/40 with respect to the peeling rate, as a result of the synergistic action of these two actions.
[0031]
Example 2
Composition of acetic acid / ethylene carbonate = 60/40 (weight ratio) that had the best peeling performance in Example 1 Remover The wafer was heated to 40 ° C., ozone was added, and the resist removal effect by the immersion treatment was examined on the wafer with the I-line novolak resist film cured by ion implantation. This film was baked at 130 ° C. for 300 seconds with IX555 (trade name, manufactured by JSR Corporation) having a thickness of 1.5 μm, and then B ⁺ 1 × 10 at 30 KeV ¹⁴ / cm ² Injected. Ethylene carbonate is slightly more decomposed by ozone than acetic acid. , Remover Experimental equipment has been made so that the number of times the liquid can be reused can be estimated when it is repeatedly recycled with ozone. In FIG. 2, the peeling instrument row | line | column and liquid supply instrument row | line | column which show the concept are shown. Although this is an experimental mechanism for single wafers for the purpose of evaluation only, it can be applied to practical production if the number of treatments in the immersion tank is increased to make it a batch type.
[0032]
The peeling treatment tank 1, the treatment liquid rinsing tank 2 and the ultrapure water rinsing tank 3 are each a quartz glass square tank in which one 6-wafer is immersed in a liquid volume of 300 mL, and the wafer 4 is a quartz glass support (not shown). ) And is subjected to a dipping process manually. In tank 1 Remover Heated to 40 ° C. by a supply pipe 8 (hereinafter, the liquid pipe is indicated by a bold line in the figure) Remover Tank 7 (initially new Remover The liquid is kept at 40 ° C. by the heater 9 through the pump P and the fine particulate filter F. There is an ozone diffuser 10 made of quartz glass on the heater, and 0.5 L / min from an ozone generator (not shown) to a pipe 11 (hereinafter, the gas pipe is indicated by a thick dotted line in the figure) and a valve 12. Ozone gas is sent and bubbled at a flow rate. The wafer is transferred to the rinsing tank 2 after 5 minutes of immersion treatment. When the processing for 6 sheets is completed, 50 mL is discharged to the tank 6 by the valve 13 and the pipe 14, 50 mL is replenished from the tank 7, and after 1 minute, the removal process for 6 wafers is similarly performed. In this manner, liquid discharge, replenishment, and processing of six wafers are repeated.
[0033]
The rinsing tank 2 has exactly the same structure as the processing tank 1, and the rinsing liquid heated to 40 ° C. at the same time when filling the liquid in the initial tank 1 from the tank 5 equipped with the heater 15 via the pump P and the fine particulate filter F. Then, the rinsing liquid supply pipe 16 is filled. Ozone gas bubbling is started at the same time as the tank 1, and when the removed wafer is immersed, it is rinsed for a predetermined time. Every time 6 sheets are rinsed, 15 mL is discharged to the tank 6 by the valve 17 and the pipe 18, and 15 mL is replenished from the tank 5. The wafer after the ozone bubbling rinsing was subjected to overflow rinsing (mechanism not shown) with ultrapure water at room temperature in the tank 3, and dried with a spin dryer (not shown).
[0034]
When the immersion time in each tank was 2 minutes, no resist residue was visually observed immediately after drying, and surface adhesion of undecomposed cured resist fine pieces was examined with a microscope, but was not observed. Further, a chip was cut out from the first processed wafer and used as a sample for charged particle activation analysis. The amount of residual organic carbon on the surface is 2.7 x 10 ¹³ Atom / cm ² Thus, the cured resist was sufficiently removed.
[0035]
Although the resist film is peeled off by the treatment in the tank 1, floating of undecomposed hardened resist fine pieces occurs in the liquid. In order to sufficiently decompose the fine pieces of the discharged liquid in the tank 6, ozone gas was bubbled from the gas diffuser 22 at a flow rate of 1 L / min by the valves 19 and 20 and the gas pipe 21 when the liquid volume reached 100 mL. Let After 5 minutes when the liquid volume becomes 200 mL, nitrogen gas is bubbled from the diffuser 22 through the high purity nitrogen gas pipe 23, the valve 24 and the valve 20 for 5 minutes, and ozone dissolved from the liquid in the tank is removed. After deaeration, the liquid is transferred to the tank 7 through the connecting pipe 25 by the valve 26 and the liquid feed pump P. The tanks 6 and 7 are provided with heaters 27 and 28, and the temperature of the liquid inside is kept at about 40 ° C. Tanks 5 and 7 are new Remover An introduction pipe 29 and a valve 30 attached thereto are provided, and disposal of the liquid is performed by a waste pipe 31 and an attached valve 32.
[0036]
In the liquid supply system, the hardened resist fine pieces that could not be decomposed by ozone were cured 1 × 10 ¹⁴ / cm ² The amount of ion implantation is very small, Remover A large burden is not imposed on the filter attached to the supply pipe 8. Therefore, if the performance degradation of the processing liquid occurs, Remover This is thought to be based on a decrease in peeling performance due to an increase in reaction products with ozone itself. Therefore, following the first 6 wafer processing, the above circulating fluid is supplied 6 times × 19 times, that is, 114 wafers using a resist film wafer that is not ion-implanted, and the last wafer is ion-implanted. It was done by. Immediately after the drying, the resist removal state is evaluated in the same way as the original sample, and the surface is visually observed and the result of charged particle activation analysis (residual carbon content: 3.4 × 10 ¹³ Atom / cm ² ), It was confirmed that the ability to remove the cured resist film was not different from the original solution.
[0037]
Used for 120 sheets processed Remover Is 1.2L, and 100 sheets can be processed per 1L. In the case of the conventional method, since 300 mL is usually used for every six sheets, 20 sheets are processed per liter. With this mixed solution, the life of the liquid can be increased to five times that of the conventional method by resist decomposition with ozone. This is because ethylene carbonate is not easily decomposed by ozone like acetic acid.
[0038]
Example 3
In the process of removing the organic film on the surface having a fine gap, the film adhering to the side surface and the bottom in the gap may remain unremoved, and it is necessary to add a precise removal process. Due to the miniaturization of VLSI, a resist-modified film is formed on the sidewalls of the fine holes by dry etching with a high aspect ratio. The masked resist is generally removed by oxygen plasma ashing, but since this altered film remains, wet removal with a stripping solution is followed. As miniaturization progresses, a resist removal solution having as small a surface tension and viscosity as possible is required for processing inside the micropores. Then, HFE-7100 was used as a solvent that dissolves ozone well, and the resist stripping action was examined as a mixed solution with acetic acid.
[0039]
The film to be removed is IX500 (trade name, manufactured by JSR Corporation) with a thickness of 1.5 μm, which is baked at 140 ° C. for 60 seconds. The single-wafer experimental system was configured with the removal treatment tank 1, the rinsing tank 2, and a small HFE vapor drying tank (not shown) containing the HFE liquid in Example 2. The wafer was held by the support of the same example and processed in each tank in order. Tank 1 and tank 2 were filled with the mixed solution and heated to 40 ° C., and bubbling of ozone gas was carried out in the same manner as in Example 2 in tank 1 alone. Remover The mixing ratio (weight) of HFE / acetic acid was 90/10, 80/20, and 60/40. However, at a mixing ratio of 90/10, it could not be removed even after being immersed for 2 minutes. When the mixing ratio was 80/20, it took 1 minute to remove it. After rinsing in tank 2 for 1 minute, it was dried with HFE-7100 vapor and the removal surface was observed with a microscope. When the mixing ratio was 60/40, the time required for removal in the tank 1 was 45 seconds and the peeling speed was about 2 μm / min. Sufficient removal performance was obtained for this kind of removal purpose. The surface tension and viscosity are 16 dyn / cm and 0.6 cP at a mixing ratio of 80/20, and are 18 dyn / cm and 0.7 cP at a mixing ratio of 60/40, and 27 dyn / cm and 1.0 cP in the case of ozone acetic acid treatment. Compared to the above, the wettability to the minute gap was remarkably improved.
[0040]
Example 4
In Example 3, a resist removal solution having a small surface tension and a low viscosity was shown. However, in order to satisfy the peeling speed, a mixed solution composed of ethylene carbonate (concentration 1% by weight) and a mixture of HFE-7200 and acetic acid was used. The same resist removal experiment as in Example 3 was performed. The liquid in the steam drying tank is HFE-7200. Even when HFE / acetic acid = 90/10 (weight ratio), a peeling speed of 3 μm / min is obtained. In this case, the surface tension and viscosity of the treatment liquid are almost the same as those of HFE. When the mixing ratio is 80/20, the peeling rate is 4.5 μm / min, which is quite close to the peeling rate of ozone-added acetic acid.
[0041]
Example 5
Fluorine detergents with low surface tension and low viscosity are the most effective for precision cleaning of parts with complex surface shapes. Therefore, the removal effect and regeneration effect of the organic film removing liquid by ozone of the present invention were investigated using a mixed solution composed of tert-butyl alcohol (concentration: 10% by weight) and HFE-7100 solvent, which has relatively little reaction with ozone. It was. It is known that a fluorine-based detergent added with alcohol dissolves rosin-based flux. This flux was to be removed, and was applied onto the oxidized wafer used in each example to obtain a removed sample. The experimental apparatus was the same as that of Example 3, and a series of treatments were performed in the same manner as in Example 3 after 1 minute of removal treatment by ozone bubbling. Although the flux was removed visually, the removal was further confirmed by charged particle activation analysis. Although 20 sheets were processed in the tank 1, the color in the liquid in the tank was not changed due to flux dissolution, and it is considered that the flux was decomposed.
[0042]
Fluorine-based cleaning agents that have solved environmental problems are more expensive than other solvents, but if the dissolved organic coating is decomposed by ozone and the life of the cleaning agent is extended, the economic difficulty can be alleviated, and fluorine The application field of film removal that takes advantage of the system can be expanded. Therefore, the polyvinyl butyral coating on the copper plate was coated with a mixture of 70% by weight of HFE-7200, 20% by weight of acetic acid, and 10% by weight of butyl acetate, using the experimental apparatus of Example 3 for each treatment time of 5 minutes. I tried to peel off. The film removal was confirmed visually.
The same treatment was applied to the vinyl chloride resin plate-like sample in which the oil film of the drying oil remained, and an attempt was made to remove the oil film. Remover The composition of HFE-7200 is 70% by weight, acetic acid 20% by weight, and decane 10% by weight. Although each treatment time was 2 minutes, no film remained visually, and the blue colored state of the liquid derived from dissolved ozone recovered after the treatment time had elapsed.
[0043]
Example 6
Using the exfoliation treatment tank 1 and the ozone diffuser 10 of Example 2, this tank is set directly above the vibrator in the water tank containing the throw-in type 28 KC ultrasonic vibrator, and the coating film is removed. investigated. The objects to be peeled off are a polymethyl methacrylate coating and a polyvinyl acetate coating on a 10 cm square stainless steel plate. Remover The composition is a mixed solution of 70% by weight of propionic acid and 30% by weight of butyl acetate. Treatment was at 20 ° C. In the same manner as in Example 2, ozone was bubbled, the sample was immersed after 5 minutes, and the ultrasonic wave was stopped for 30 seconds and repeated for 10 seconds. Although the thickness of the coating was not measured, peeling was confirmed visually in about 5 minutes in the case of a polymethylmethacrylate coating and in about 3 minutes in the case of a polyvinyl acetate coating.
[0044]
【The invention's effect】
The present invention has an excellent dissolving power for an organic film composed of a specific mixed solution. Remover The organic coating is removed by dissolving ozone in this, and various ozone-decomposable organic coatings can be removed. Also, Remover In order to increase the decomposition power of ozone, it is difficult to react with ozone. Remover In addition, ozone can be dissolved at a high concentration, and the reaction product after decomposition has a low molecular weight, dissolves well in the processing solution, does not contaminate the substrate, and does not contaminate the substrate. The dissolved organic film-derived component can be decomposed by treatment with ozone gas in a different area from the treatment area, and the treatment liquid can be regenerated and reused. At the same time, the performance is remarkably improved and there are no environmental problems and resource saving can be achieved.
[Brief description of the drawings]
FIG. 1 is a diagram showing the correlation between the composition ratio of acetic acid: ethylene carbonate obtained in Example 1 and the resist stripping rate.
FIG. 2 is a diagram showing an outline of a stripping instrument array and a liquid supply instrument array for a single-wafer experimental mechanism used in Example 2;
[Explanation of symbols]
1. Stripping treatment tank Treatment liquid rinse tank
3. Ultra pure water rinsing tank 4. Wafer
5,6,7. Tank 8 Treatment liquid supply pipe
9. Heater 10. Ozone diffuser
11. Piping 12,13. valve
14 Piping 15. Heater
16. Rinse solution supply pipe 17. valve
18. Piping 19,20. valve
21. Gas piping 22. Diffuser
23. Nitrogen gas piping 25. Connecting pipe
26. Valve 27,28. Heater
29. new Remover Introducing pipe 30. valve
31. Waste pipe 32. valve

Claims (11)

In the method of removing the organic film by bringing a treatment liquid in which ozone gas is dissolved into contact with a substrate having an ozone decomposable organic film on the surface, the treatment liquid comprises:
(a) Organic substance selected from alkylene carbonate, acetic acid alkyl ester, tert- butyl alcohol, and paraffinic saturated hydrocarbon represented by the formula: C _m H _{2m + 2} (where m = an integer of 10 to 12 ) When,
(b) Formula: consisting C _n H _2n + 1 COOH fatty acid represented by (wherein, n = 1 to 3 integer), and / or C ₄ F ₉ OCH ₃ and C ₄ F ₉ OC ₂ H ₅ Solution with at least one hydrofluoroether selected from the group (provided that the component (a) and / or the component (b) includes at least one water-miscible component)
A method for removing an organic film, wherein ozone is dissolved in the organic film. The component (a) is at least one selected from alkylene carbonate and alkyl acetate , and the component (b) is the fatty acid or a mixture of the fatty acid and the hydrofluoroether. The method of claim 1, characterized in that: Wherein component (a) is a tert- butyl alcohol, and The method of claim 1, wherein the component (b) characterized in that it is a Hydro fluoroether said. In the method of removing the organic film by bringing a treatment liquid in which ozone gas is dissolved into contact with a substrate having an ozone decomposable organic film on the surface, the treatment liquid comprises:
(a) a fatty acid represented by the formula: C _n H _{2n + 1} COOH (where n is an integer of 1 to 3) ;
(b) a solution with 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
A method for removing an organic film, wherein ozone is dissolved in the organic film. It is a method of any one of Claims 1-4 , Comprising: The process liquid after an organic film removal process is transferred to the area different from the area which performs the said process, and after processing with ozone gas, the said process is performed. Returning to the application area and reusing it as a processing liquid for processing another substrate. 6. The method according to any one of claims 1 to 5 , wherein the organic coating is a resist film. An organic film removing agent used for dissolving ozone and bringing it into contact with a substrate having an ozone decomposable organic film on its surface to remove the organic film,
(a) Organic substance selected from alkylene carbonate, acetic acid alkyl ester, tert- butyl alcohol, and paraffinic saturated hydrocarbon represented by the formula: C _m H _{2m + 2} (where m = an integer of 10 to 12 ) , And
(b) Formula: consisting C _n H _2n + 1 COOH (wherein, n = 1 to 3 integer) fatty acid represented by, and / or C ₄ F ₉ OCH ₃ and C ₄ F ₉ OC ₂ H ₅ comprise at least one hydrofluoroether selected from the group (provided that the (a) component and / or said (b) at least one water miscible component as component)
Organic film remover characterized by The component (a) is at least one selected from alkylene carbonate and alkyl acetate , and the component (b) is the fatty acid or a mixture of the fatty acid and the hydrofluoroether. The organic film removing agent according to claim 7, which is characterized by: Wherein component (a) is a tert- butyl alcohol, and the organic film removing agent according to claim 7, wherein the component (b) is a Hydro fluoroether said. An organic film removing agent used for dissolving ozone and bringing it into contact with a substrate having an ozone decomposable organic film on its surface to remove the organic film,
(a) a fatty acid represented by the formula: C _n H _{2n + 1} COOH (where n is an integer of 1 to 3) ;
(b) 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
The organic film removing agent which comprises a. The organic film removing agent according to any one of claims 7 to 10 , which is used for removing a resist film.

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