KR20060003346A - Resist stripping method and device - Google Patents

Abstract

A resist stripping method and device that enable resist on a substrate surface to be stripped with high efficiency. A method of stripping resist on a substrate surface includes at least a step (1) of applying an ozone solution to a surface to be treated and the step (2) of applying an organic solvent to the surface to be treated.

Description

RESIST STRIPPING METHOD AND DEVICE

The present invention relates to a resist removal method and a resist removal apparatus capable of removing the resist on the substrate surface with high efficiency.

When forming a circuit on a semiconductor substrate, or when forming a plurality of colored pixels having different colors on a liquid crystal substrate in a pattern form, a photolithography step is an essential step. For example, in the case of forming a circuit on a semiconductor substrate, a resist is applied on the wafer, and an image including a resist pattern is formed by a conventional photo process, and this is etched as a mask, and then unnecessary resist is removed by The circuit is formed, and the resist is applied again to form the next circuit, and the cycle of image formation-etching-resist removal is repeatedly performed.

In the resist removal step of removing unnecessary resist, conventionally, an RCA cleaning method using an asher (chemical means), sulfuric acid, hydrogen peroxide, or the like is used for removing a resist of a semiconductor substrate. A mixed solution of a solvent and an amine and the like were used. However, if the asher is used to remove the resist, there is a risk of damaging the semiconductor due to the high temperature, and it is impossible to remove the inorganic impurities. In addition, when removing a resist using a solvent or a chemical agent, a new chemical liquid must be replaced every tens of batches. Therefore, a large amount of chemical liquid is required, and the cost of the chemical liquid increases, and a large amount of waste liquid is generated to treat the waste liquid. The city also suffered a significant disadvantage in both cost and environment.

On the other hand, ozone water obtained by dissolving ozone gas in water exhibits an excellent effect on sterilization, deodorization and bleaching due to the strong oxidizing power of ozone, and furthermore, ozone gas is self-decomposed with harmless oxygen (gas) with time and its residual properties It is attracting attention as an environmentally friendly disinfectant, cleaner, and bleach agent. In recent years, with increasing interest in the environment, a resist removal process using ozone water has attracted attention as an alternative to the above-described resist removal method.

However, under normal temperature and pressure, ozone can only be dissolved in water at a concentration of about 50 ppm, and it is difficult to apply industrially because ozone water at this concentration requires a long time to remove a resist.

On the other hand, organic acids, especially acetic acid, can dissolve ozone at a higher concentration than water, and can be used stably without being decomposed by ozone. In particular, when the organic acid concentration is 500,000 ppm or more, very high concentrations of ozone can be dissolved. Therefore, it was considered to use ozone-organic acid solution dissolved in organic acid for resist removal.

For example, Japanese Unexamined Patent Application Publication No. 2001-340817 discloses a cleaner for removing pollutants formed by dissolving ozone in an organic solvent having a partition coefficient of 0.6 or more in the gas, and acetic acid is exemplified as such an organic solvent. have. However, such a high purity (high concentration) acetic acid and the like has a problem that the irritating smell is strong and flammable, and also very expensive for drainage treatment. Moreover, although ozone concentration is reliably improved by using a high concentration organic acid, there existed a problem that the resist removal efficiency of the expectation level was not acquired depending on the kind of resist.

Summary of the Invention

In view of the above-described phenomenon, an object of the present invention is to provide a resist removing method and a resist removing apparatus capable of removing a resist on a substrate surface with high efficiency.

1st this invention is a method of removing the resist on the surface of a board | substrate, It is a resist removal method which has at least the process 1 which makes an ozone solution act on a process surface, and the process 2 which makes an organic solvent act on a process surface. In the resist removal method of 1st this invention, it is preferable that an organic solvent is a water-soluble organic solvent.

An apparatus for removing a resist on the surface of a substrate, and at least a resist removing apparatus having means for injecting an ozone solution onto the treated surface and means for injecting an organic solvent onto the treated surface is also one of the present invention.

The second invention is a method of removing a resist on the surface of a substrate using an ozone solution in which ozone gas is dissolved in an organic acid aqueous solution, and a resist removal method having an organic acid concentration in the ozone solution of less than 5000 ppm.

The third aspect of the present invention is a method of removing ozone water by supplying ozone water to a substrate to remove resist on the surface of the substrate, wherein the ozone water is a resist removal method in which pH is adjusted to 4-8. In the resist removal method of the third invention, the ozone water preferably has an organic acid concentration of less than 5000 ppm, preferably contains a reagent having a buffering effect of pH, and preferably has an ozone concentration of 40 ppm or more.

In the resist removal method of the first, second or third aspect of the present invention, the resist is preferably a novolak-type resist, and it is preferable to cause the ozone solution to act on the treated surface while irradiating ultraviolet rays.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the relationship between the resist film thickness and processing time at the time of removing using an ozone solution.

FIG. 2 is a diagram showing a relationship between a resist film thickness and processing time in Example 1 and Comparative Example 1. FIG.

3 is a photomicrograph of the surface state of the treated surface 60 seconds after the start of the treatment in Example 1 and Comparative Example 1. FIG.

4 is a diagram showing a relationship between resist film thickness and processing time in Examples 2, 3, and 4 and Comparative Examples 2 and 3. FIG.

5 is a photomicrograph of the surface state of the treated surface 80 seconds after the start of the treatment in Examples 2 and 3 and Comparative Examples 2 and 3. FIG.

FIG. 6 is a diagram showing a relationship between resist film thickness and processing time in Examples 5, 6, and 7 and Comparative Examples 4 and 5. FIG.

Hereinafter, the present invention is disclosed.

The inventors have investigated in detail aspects of resist removal by ozone solution and found that there are two steps in the removal process. Fig. 1 shows an example of the relationship between the resist film thickness and the treatment time when removing the resist by the ozone solution.

It can be seen from FIG. 1 that the removal of the resist by the ozone solution is divided into a first step in which the film thickness of the resist is rapidly reduced in a relatively short time, and a second step until the resist disappears completely in succession. have.

As a result of the analysis by the present inventors, it is mainly the resin component to be removed in the first step, and after the resin component is removed, a component mainly containing nitrogen (hereinafter also referred to as residue) remains to remove the residue. It has been found that the second step requires more time than the first step to affect the resist removal efficiency as a whole.

Therefore, in order to improve the resist removal efficiency as a whole, it is particularly important to shorten the time required for the second step.

Moreover, such a residue is especially seen in the case of a novolak-type resist, and is considered to originate from photosensitizers, such as orthodiazoquinone.

The resist removal method of 1st this invention is a method of removing the resist on the surface of a board | substrate, and has at least the process 1 which makes an ozone solution act on a process surface, and the process 2 which makes an organic solvent act on a process surface.

As a result of further investigation by the present inventors, the removal rate of the first stage is sufficient as long as the removal rate of the first stage is obtained as long as the ozone solution of a certain concentration or more is used, whereas the removal rate of the second stage is slow in the ozone solution, and by using an organic solvent, It has been found to be greatly improved, and the present invention has been completed. This effect is considered to be common to all resists using diazo-based compounds as well as orthodiazoquinones.

In the resist removal method of the first aspect of the present invention, step 1 is a step of mainly removing the resin component of the resist in response to the first step described above, and step 2 is mainly removing a residue in response to the second step described above. It is a process.

The ozone solution used in step 1 can be produced by dissolving ozone gas in water. The water which dissolves ozone gas may contain organic acids, such as acetic acid. By containing an organic acid, a higher concentration of ozone can be dissolved.

Although it does not specifically limit as a method of manufacturing the said ozone solution, For example, it is preferable to use the ozone dissolution module which accommodated the gas permeable membrane containing a nonporous membrane. In the present specification, the non-porous membrane refers to a membrane that allows gas to pass through but does not permeate liquid. Using such an ozone dissolving module, the ozone molecules penetrate between the molecular chains of the resin constituting the gas permeable membrane and diffuse into the aqueous organic acid solution. However, the gas permeable membrane does not block or bubbles that degrade the resist removal efficiency are mixed. In addition, the ozone solution once used for removing the resist may be circulated and used, and an ozone solution having a high ozone concentration can be easily and efficiently obtained.

The organic solvent to be used in Step 2 is not particularly limited as long as the residue can be dissolved efficiently, but a water-soluble organic solvent is preferable. When using a water-soluble organic solvent, process 2 can be performed continuously, without requiring operation, such as drying a process surface after completion | finish of process 1. In addition, when using a water-soluble organic solvent, it can also be used as a liquid mixture of water and a water-soluble organic solvent.

Although it does not specifically limit as said water-soluble organic solvent, For example, Alcohol, such as methanol, ethanol, 1-propanol, 2-propanol, ethylene glycol; Oxides such as ethylene oxide and propylene oxide; Aldehyde ketones such as formaldehyde, acetaldehyde, glyoxal and acetone; Carboxylic acids such as formic acid, acetic acid, n-butyric acid, oxalic acid and citric acid; Aliphatic amines such as triethanolamine; Organic sulfur compounds, such as methanesulfonic acid and dimethyl sulfoxide (DMSO), etc. are mentioned.

The conditions for acting the ozone solution on the treated surface in the step 1 and the condition for acting the organic solvent on the treated surface in the step 2 are not particularly limited and can be appropriately selected depending on the type and thickness of the resist. Since the removal rate of a resist tends to become faster at high temperature in the range which does not affect the ozone concentration in the said ozone solution, about 50 degreeC is preferable as a processing temperature. When the ozone solution is acted on in step 1 and the organic solvent is acted on in step 2, the ozone solution acts on the treated surface while irradiating ultraviolet rays, unless the substrate is a substrate easily penetrating into ultraviolet rays such as a GaAs substrate. It is preferable to make it. By using ultraviolet-ray together, the peeling effect of a higher resist can be acquired. However, there are also problems such as running costs incurred by lamp replacement, which complicates the reaction tank.

As said ultraviolet-ray, it is preferable that wavelength is about 254 nm. Moreover, although it does not specifically limit as irradiation intensity of an ultraviolet-ray, When a radiation is irradiated with the intensity of about 0.01 mW / cm <^2> or more, sufficient effect can be acquired.

Although it does not specifically limit as a resist to which the resist removal method of 1st this invention is applied, Especially it is effective with respect to the novolak-type resist with a large amount of the said residue.

In addition, a novolak-type resist contains a novolak resin as a main component, and also contains photosensitizers, such as orthodiazoquinone, etc., and can change solubility to an alkaline solution by light irradiation. Novolak-type resists are currently used in most substrates, such as a glass substrate, a compound substrate, and a silicon substrate.

According to the resist removing method of the first aspect of the invention, the resist on the substrate surface can be removed with high efficiency. When water-soluble organic solvents, such as methanol and ethanol, are used especially as an organic solvent as a liquid mixture with water, the quantity of the organic solvent discharged can be suppressed to the minimum, and the load on an environment can also be minimized.

This resist removal method of this 1st this invention can be implemented suitably by using the resist removal apparatus which has a means which injects an ozone solution to a process surface, and a means which injects an organic solvent into a process surface.

An apparatus for removing a resist on such a substrate surface, and at least a resist removing device having means for injecting an ozone solution onto the treated surface and means for injecting an organic solvent onto the treated surface is also one of the present inventions.

The means for injecting an ozone solution onto the treatment surface and the means for injecting an organic solvent onto the treatment surface are not particularly limited, and conventionally known nozzles and the like can be used. In this case, the nozzles may be provided separately for the ozone solution and the organic solvent, or may share a single nozzle.

It is preferable that the said nozzle is a rod-shaped nozzle. As a result, the resist can be removed with higher efficiency.

In the present specification, the rod-shaped nozzle means a nozzle capable of reaching the processing surface of the substrate as a rod having a diameter substantially equal to the nozzle inner diameter without spreading the ozone water injected from the nozzle to exceed the inner diameter of the nozzle. The upper limit with preferable injection angle of the said rod-shaped nozzle, ie, the enlargement angle of ozone water injected from the nozzle, is 10 degrees, and a more preferable upper limit is 5 degrees. More preferably, the cross-sectional shape of the ozone water in the vertical direction is almost similar to the spraying direction immediately after the spraying from the nozzle and when reaching the processing surface of the substrate, and is perpendicular to the spraying direction at the point of arrival of the substrate processing surface. The cross-sectional area of ozone water is within 120% of the nozzle opening area.

Such a rod-shaped nozzle can be obtained by performing a punching process on a tubular member using a drill, a laser, etc., or using hollow fiber as a nozzle.

Moreover, it is preferable that the said nozzle is arrange | positioned so that the ozone solution or an organic solvent may be inject | poured with respect to the substantially whole surface of the board | substrate used for a process. By spraying the ozone solution or the organic solvent in this manner, the resist on the entire surface of the substrate can be removed uniformly and efficiently.

2nd this invention is a method of removing the resist on the surface of a board | substrate using the ozone solution which dissolved ozone gas in the organic acid aqueous solution, and is a resist removal method whose organic acid concentration in the said ozone solution is less than 5000 ppm.

By using an organic acid aqueous solution, ozone gas can be dissolved at a higher concentration, and when a high concentration of ozone solution is used, resist can be removed with higher efficiency. However, on the other hand, when the concentration of the organic acid in the ozone solution becomes high, problems such as irritating odor, flammability, drainage treatment, etc. occur, and on the contrary, the removal efficiency of the resist deteriorates.

As a result of earnest examination, the present inventors have found that the use of an aqueous solution of an organic acid having a constant concentration range can suppress the occurrence of problems such as irritating odor, flammability and drainage treatment, and can remove resist with very high efficiency. 2 this invention was completed.

As described above, the removal of the novolak-type resist by the ozone solution mainly includes a first step of removing the novolak resin component, and a nitrogen component which is subsequently believed to be derived from a photosensitizer such as orthodiazoquinone. It is divided into a second step of removing the residue (see Fig. 1), the inventors further examined, as a result, the removal rate of the first step is almost constant rate when the organic acid concentration is above a certain level, the second step The removal rate of was found to be rather slow as the organic acid concentration was increased, and this was considered to be the cause.

In the second removal method of the resist of the present invention, by limiting the concentration of the organic acid in the ozone solution to less than 5000 ppm, a necessary and sufficient removal rate is obtained in the first step, and the residue containing the nitrogen component is removed in the second step. There is no case to disturb. This effect is considered to be common to all resists using diazo-based compounds as well as orthodiazoquinones.

Although it does not specifically limit as said organic acid, For example, acetic acid, n-butyric acid, oxalic acid, citric acid, or derivatives thereof which are low in reactivity with ozone are preferable. Among them, acetic acid, n-butyric acid, citric acid or derivatives thereof are more preferable, and acetic acid, citric acid or derivatives thereof having a relatively low toxicity is more preferable.

Although it does not specifically limit as said derivative of acetic acid, Since the reactivity with ozone is low, halogenated acetic acid, such as monofluoroacetic acid, difluoroacetic acid, trifluoroacetic acid, etc. are preferable, for example.

The concentration of the organic acid in the ozone solution is less than 5000 ppm. If it is 5000 ppm or more, advanced drainage treatment is required, and removal efficiency deteriorates depending on the kind of resist. Preferably it is 500 ppm or less.

Since the said organic acid improves very high ozone dissolution efficiency only by adding a very small amount, there is no minimum in particular of the concentration in the ozone solution of the organic acid, but 0.001 ppm or more is preferable and 0.005 ppm or more is more preferable. Do.

Although it does not specifically limit as a resist to which the resist removal method of 2nd this invention is applied, Especially, it is especially effective with respect to novolak-type resist similarly to the resist removal method of said 1st this invention.

Although it does not specifically limit as a method of manufacturing the said ozone solution used for the removal method of the resist of 2nd this invention, For example, it is the same as the method of manufacturing the ozone solution in the resist removal method of 1st this invention mentioned above. It is preferable to use an ozone dissolution module containing a gas permeable membrane including a nonporous membrane.

In the resist removal method of 2nd this invention, it is preferable to spray the said ozone solution with the linear velocity of 460 cm / sec or more with respect to the substantially whole surface of the board | substrate used for a process. By spraying the ozone solution in this way, the resist on the entire surface of the substrate can be removed uniformly and efficiently.

In the removal method of the resist of 2nd this invention, it does not specifically limit as the processing conditions of the said ozone solution, It determines suitably according to the kind, thickness, etc. of a resist. Since the removal rate of a resist tends to become faster at high temperature in the range which does not affect the ozone concentration in the said ozone solution, about 50 degreeC is preferable as a processing temperature.

Moreover, it is preferable to make an ozone solution act on the process surface, irradiating an ultraviolet-ray similarly to the resist removal method of the said 1st this invention.

According to the method of removing the resist of the second aspect of the present invention, the use of an ozone solution having an organic acid concentration in a constant concentration range can suppress occurrence of irritating odor, flammability, drainage treatment and the like. In addition, in the novolak-type resist, the resist on the substrate surface can be removed with high efficiency as compared with the case of using a high concentration organic acid solution.

The third aspect of the present invention is a method of removing resist on the surface of a substrate using ozone water, and the ozone water is a resist removal method in which pH is adjusted to 4 to 8.

The inventors of the present invention have examined the aspect of removing the resist on the surface of the substrate by ozone water in more detail. As a result, the removal rate of the first step shown in FIG. The removal rate of the step is highly dependent on the pH of the ozone water, and when the pH is adjusted to a certain range, it is possible to remove the residue with a very high efficiency, thereby discovering that the removal rate of the resist as a whole is improved, and the third invention Came to complete.

The resist removal method of 3rd this invention is effective for any board | substrates, such as a silicon substrate, a compound substrate, a liquid crystal substrate, and a mask substrate.

The ozone water is pH 4 to 8. If it is less than 4, the removal rate of the residue in the said 2nd step becomes slow and the resist removal rate as a whole also becomes slow. If it exceeds 8, the dissolved concentration of ozone is lowered and the resist removal rate is slowed. Preferably it is 4.5-7, More preferably, it is 4.8-6.5.

The ozone water in the resist removal method of 3rd this invention may be what melt | dissolved ozone gas in the organic acid aqueous solution. It is because ozone water can be made into high ozone concentration. However, as in the ozone water in the resist removal method of the second invention described above, the organic acid concentration is preferably less than 5000 ppm. If it is 5000 ppm or more, advanced drainage treatment is required, and the removal efficiency may deteriorate depending on the type of resist.

Although it does not specifically limit as a method of adjusting the pH of the said ozone water, It is preferable to contain the reagent which has a buffer effect of pH in ozone water, in order to maintain a stable pH through a process.

The reagent having a buffering action is not particularly limited as long as it does not cause chemical modification such as decomposition by ozone, and examples thereof include: acetate buffers such as ammonium acetate and sodium acetate; Citric acid buffers such as triammonium citrate and monosodium citrate; Phosphate buffers such as monopotassium phosphate and disodium phosphate; Boric acid buffers such as sodium tetraborate and ammonium borate; And amino acid buffers such as glycyl glycine, glycine, L-arginine, and N-ε-lauroyl-L-lysine. These reagents may be used alone or in combination of two or more.

However, depending on the type and application of the substrate, contamination with metals such as potassium and sodium, phosphorus, boron, etc. may be a problem. In such a case, a buffer containing no such element is preferable. Ammonium acetate, triammonium citrate or amino acid buffers are preferred.

It is preferable that ozone water is 40 ppm or more of ozone concentration. If it is less than 40 ppm, efficient resist removal may be difficult. More preferably, it is 50 ppm or more. Although the upper limit of the ozone concentration of the said ozone water is not specifically limited, It is preferable that it is 200 ppm or less. When it exceeds 200 ppm, the apparatus for producing ozone water may be enlarged and the cost may increase.

Although it does not specifically limit as a method of manufacturing the said ozone water used for the resist removal method of 3rd this invention, For example, it is nonporous same as the method of manufacturing the ozone solution in the resist removal method of 1st this invention mentioned above. It is preferable to use an ozone dissolution module containing a gas permeable membrane including a membrane.

In the resist removal method of 3rd this invention, it is preferable to spray the said ozone water at the linear speed of 460 cm / sec or more with respect to the substantially whole surface of the board | substrate used for a process. By spraying ozone water in this manner, the resist on the entire surface of the substrate can be removed uniformly and efficiently.

In the resist removal method of 3rd this invention, it does not specifically limit as the processing conditions of the said ozone water, It determines suitably according to the kind of board | substrate, the kind, thickness, etc. of a resist. In the resist removal method of the third invention of the present invention, the temperature particularly affects the peeling rate of the resist. Since the peeling reaction of the resist is a chemical reaction, the higher the treatment temperature is promoted in principle. On the other hand, ozone in ozone water is stable when ozone water is acidic, whereas decomposition proceeds rapidly as the pH becomes neutral to alkaline. The decomposition of ozone tends to proceed at higher temperatures. In the third aspect of the present invention, the pH of the ozone water is adjusted to 4 to 8, but depending on the pH and the temperature setting, the ozone concentration in the ozone water is rapidly decreased, and as a result, the peeling rate of the resist may decrease. In addition, in a gallium arsenide substrate or the like, it is necessary to select a temperature in accordance with the type of the substrate such as damage occurs by heating.

The optimum treatment temperature depends on the type of buffer used and the setting of pH, but is preferably about 30 to 50 ° C., and about 20 to 30 ° C. is particularly preferable for substrates having particularly low heat resistance such as gallium arsenide substrates.

Although it does not specifically limit as a resist to which the resist removal method of 3rd this invention is applied, Especially, it is especially effective with respect to novolak-type resist similarly to the resist removal method of said 1st this invention.

In addition, similarly to the resist removal method of the first aspect of the present invention, in the resist removal method of the third aspect of the present invention, ozone water may be applied to the treated surface while irradiating ultraviolet rays.

According to the third removal method of the resist of the present invention, the resist on the surface of the substrate can be removed with high efficiency by using ozone water at a constant pH.

Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited only to these Examples.

<Example 1>

Ozone gas was dissolved in an aqueous 10000 ppm acetic acid solution adjusted to 50 ° C. to obtain an ozone solution.

On the other hand, the GaAs substrate (φ100 mm, thickness 0.625 mm) was treated with HMDS (Nagase Chemtech Co., Ltd., NP-100) using a spin coater (3000 rpm, 30 seconds) as a treated sample and washed with water, followed by a resist solution ( Fuji Film Arch Co., Ltd., FHi3950) was applied and treated with a spin coater (Mikasa Co., Ltd., 1H-DX2 type) for 30 seconds at 3000 rpm, followed by further drying at 105 ° C. for 20 minutes to a size of 10 mm × 10 mm. It cut with and developed what was exposed using the I-ray stepper in alkali type. The thickness of the resist on the treated surface of this treated sample was about 1.0 μm.

Ozone water was sprayed continuously for 50 seconds so that the linear velocity at the time of reaching the obtained ozone solution with respect to the process surface of a process sample from 1500 cm / sec.

Next, methanol was sprayed continuously for 10 seconds so that the linear velocity at the time of reaching from the perpendicular | vertical direction with respect to the process surface of a process sample might be 1500 cm / sec.

The thickness of the resist was measured using a film thickness gauge (manufactured by Otsuka Denshi Co., Ltd., type FE-3000). The relationship between processing time and resist film thickness is shown in FIG.

Moreover, the surface state of the process surface 60 second after the start of a process was image | photographed using the microscope. This is shown in Figure 3a.

Comparative Example 1

The resist of the treated sample was removed in the same manner as in Example 1 except that the ozone solution was continuously sprayed without switching to methanol injection in the middle.

Moreover, the surface state of the process surface 60 second after the start of a process was image | photographed using the microscope. This is shown in Figure 3b.

From Fig. 2, in Example 1, the resist film thickness of the treated surface was rapidly decreased by ozone solution injection, and the resist was completely removed immediately after switching to methanol injection. On the other hand, in the comparative example 1, although the resist film thickness of the process surface rapidly decreased by ozone solution injection, it was impossible to remove a resist completely even if it continued to spray ozone solution as it is.

In addition, in FIG. 3, in Example 1, the resist was not fully recognized after 60 seconds of the start of the treatment, whereas in Comparative Example 1, the resist clearly remained.

<Example 2>

Ozone gas was dissolved in a 50 ppm aqueous acetic acid solution adjusted to 50 ° C. to obtain an 86 ppm ozone solution.

On the other hand, a GaAs substrate (φ100 mm, 0.625 mm thickness) was treated with HMDS (Nagase Chemtech Co., Ltd. NP-100) as a treated sample and washed with water, followed by coating with a resist liquid (Fuji Film Arch Co., FHi3950). After treatment at 3000 rpm for 30 seconds with a spin coating machine (Mikasa Co., Ltd., 1H-DX2 type), the dried product was further cut at 10 mm x 10 mm for 20 minutes at 105 ° C, and exposed using an I-line stepper. Was developed in an alkali system. The film thickness of the resist on the treated surface of this treated sample was 1.189 µm.

The ozone water was sprayed continuously so that the linear velocity at the time of reaching the obtained ozone solution with respect to the process surface of a process sample from 1500 cm / sec. The film thicknesses of the resists 40, 60, 80, 100 and 120 seconds after the start of the treatment were measured using a film thickness gauge (model FE-3000, manufactured by Otsuka Denshi Co., Ltd.).

The relationship between the processing time and the resist film thickness is shown in FIG. 4.

4A is a plot of the change in the resist film thickness immediately after the start, and FIG. 4B is a plot of the change in the resist film thickness from the beginning of 40 seconds after the enlargement of the vertical axis.

In addition, the surface state of the process surface 80 second after the start of a process was image | photographed using the microscope.

This is shown in Figure 5a.

<Example 3>

Ozone gas was dissolved in an aqueous 500 ppm acetic acid solution adjusted to 50 ° C. to obtain an 87 ppm ozone solution.

The resist of the process sample was removed like Example 2 except having used the obtained ozone solution. In addition, the surface state of the process surface 80 second after the start of a process was image | photographed using the microscope. This is shown in Figure 5b.

Comparative Example 2

Ozone gas was dissolved in distilled water adjusted to 50 캜 to obtain an ozone solution with a concentration of 75 ppm.

The resist of the process sample was removed like Example 2 except having used the obtained ozone solution. In addition, the surface state of the process surface 80 second after the start of a process was image | photographed using the microscope. This is shown in Figure 5c.

Comparative Example 3

Ozone gas was dissolved in a 5000 ppm acetic acid aqueous solution adjusted to 50 ° C. to obtain an 87 ppm ozone solution.

The resist of the process sample was removed like Example 2 except having used the obtained ozone solution. In addition, the surface state of the process surface 80 second after the start of a process was image | photographed using the microscope. This is shown in Figure 5d.

<Example 4>

Ozone gas was dissolved in a 50 ppm aqueous acetic acid solution adjusted to 50 ° C. to obtain an 86 ppm ozone solution.

On the other hand, a Si substrate (φ100 mm, thickness 0.625 mm) was treated with HMDS as a treated sample and washed with water, and then a resist liquid (manufactured by Tokyo Corporation, THMRIP3100) was applied, and a spin coating machine (manufactured by Mikasa, 1H-DX2 type) After treating at 3000 rpm for 30 seconds, the dried product at 105 ° C. for 20 minutes was further cut into a size of 10 mm × 10 mm, and the one exposed using an I-line stepper was developed in an alkali system. The film thickness of the resist on the treated surface of this treated sample was 1.189 µm.

The ozone water was sprayed continuously so that the linear velocity at the time of reaching the obtained ozone solution with respect to the process surface of a process sample from 1500 cm / sec. At this time, it operated by irradiating an ultraviolet-ray to a process surface so that the ultraviolet-ray intensity in a process surface might be set to 1.2 mW / cm <^2> using the UV lamp (C-250WF by the Chemitronics company) of wavelength 254nm. The film thicknesses of the resists 40, 60, 80, 100 and 120 seconds after the start of the treatment were measured using a film thickness gauge (model FE-3000 manufactured by Otsuka Denshi Co., Ltd.).

The relationship between the processing time and the resist film thickness is shown in FIG. 4.

From Fig. 4, in Examples 2 and 3, the resist thickness rapidly decreased after the start of the treatment, and the resist was almost completely removed until 80 seconds later. On the contrary, in Comparative Example 2, sufficiently high ozone concentration was not obtained in distilled water, and removal of the resist was very slow. On the other hand, in Comparative Example 3, although a very high concentration of ozone solution was obtained by using 5000 ppm of acetic acid solution, the initial resist removal rate was faster than that of Examples 2 and 3, but after 60 seconds, The resist was hardly removed completely.

In Example 4, the initial resist removal rate was equivalent to that of Comparative Example 3, and similarly to Examples 2 and 3, the resist was almost completely removed until 80 seconds later.

In addition, from FIG. 5, when the surface state of the process surface 80 seconds after the start of a process was compared, the resist was not recognized at all in Example 2, and only the trace of the trace grade was left also in Example 3. On the contrary, in Comparative Example 2, most of them were the same as untreated, and in Comparative Example 3, the resist clearly remained.

Further, in Examples 2 to 4, the COD was treated by the method according to JIS K 0102-17 (Oxygen consumption amount (COD _Mn ) with potassium permanganate at 100 ° C) with respect to the waste liquid obtained by UV irradiation of the liquid after removing the resist. And TOC (organic carbon) were measured by the method according to JIS K 0102-22.2 (Infrared TOC automatic measurement method).

The results are shown in Table 1 below.

COD (mg / L) TOC (mg / L) Example 2 15 10 Example 3 59 190 Example 4 9 7

From Table 1, the COD of the waste liquid of Examples 2-4 is 160 mg / which is the drainage standard of the factory which Japan establishes (Prime Ministerial Decree Attachment Table 2: Revised Prime Ministerial Decree 40th on August 27, 2015). It was found that the load on the environment was very small, far below L.

Example 5

A 0.25-inch-thick mask blank (approximately 0.5 µm thick resist on the substrate surface) coated with Nagase Chemtech's positive i-line resist 895i was cut into a size of 30 mm x 30 mm to obtain a treated sample.

The 50 ppm aqueous acetic acid solution was adjusted to pH 5 with 64 ppm ammonium acetate. Ozone gas was dissolved in this solution to obtain ozone water. The ozone concentration in the obtained ozone water was 80 ppm, and pH was 4.8.

The obtained ozone water was heated to 50 ° C, and continuously sprayed so that the linear velocity at the time of reaching from the vertical direction with respect to approximately the entire surface of the treated surface of the treated sample was 1500 cm / sec. The film thickness of the resist 15, 30, 45, 60, and 90 second after the start of processing was measured using a film thickness meter (model FE-3000, manufactured by Otsuka Denshi Co., Ltd.).

The relationship between the processing time and the resist film thickness is shown in FIG. 6.

6A plots the change in resist film thickness immediately after the start, and FIG. 6B plots the change in the resist film thickness from 40 seconds after the start on an enlarged scale of the vertical axis.

<Example 6>

50 ppm aqueous citric acid solution was adjusted to pH 8 with 60 ppm ammonium citrate. Ozone gas was dissolved in this solution to obtain ozone water. The ozone concentration in the obtained ozone water was 60 ppm, and pH was 7.7.

The resist of the process sample was removed like Example 5 except having heated and used the obtained ozone water at 30 degreeC.

The results are shown in FIG.

<Example 7>

Ozone gas was obtained by dissolving ozone gas in an aqueous solution adjusted to pH 7 with a concentration of 0.7 mol / L phosphate-boric acid buffer. The ozone concentration in the obtained ozone water was 77 ppm, and pH was 6.5.

The resist of the process sample was removed like Example 5 except having heated and used the obtained ozone water at 30 degreeC.

The results are shown in FIG.

<Comparative Example 4>

An aqueous 50 ppm acetic acid solution was adjusted to pH 9.0 with 1% ammonium. Ozone gas was dissolved in this solution to obtain ozone water. The ozone concentration in the obtained ozone water was 5 ppm, and pH was 9.0.

The resist of the process sample was removed like Example 5 except having heated and used the obtained ozone water at 30 degreeC.

The results are shown in FIG.

Comparative Example 5

Ozone gas was dissolved in ultrapure water (pH 6.5) to obtain ozone water. The ozone concentration in the obtained ozone water was 70 ppm, and pH was 3.2.

The resist of the process sample was removed like Example 5 except having heated and used the obtained ozone water at 50 degreeC.

The results are shown in FIG.

From Fig. 6, in Examples 5 to 7, the resist thickness rapidly decreased after the start of the treatment, and the resist was almost completely removed until 80 seconds later. In contrast, in Comparative Example 4, even when the pH was high, sufficiently high ozone concentration was not obtained, and removal of the resist was very slow. On the other hand, in the comparative example 5, although the initial resist removal rate was equivalent to the case of Examples 5-7, the resist was hardly removed completely.

According to the present invention, it is possible to provide a resist removing method capable of removing the resist on the substrate surface with high efficiency.

Claims (10)

A method of removing the resist on the surface of a substrate, at least having a step 1 of causing an ozone solution to act on the treated surface and a step 2 of acting an organic solvent on the treated surface. The method of claim 1 wherein the organic solvent is a water soluble organic solvent. An apparatus for removing a resist on a surface of a substrate, wherein at least the apparatus has a means for injecting an ozone solution onto the treated surface and a means for injecting an organic solvent onto the treated surface. A method of removing a resist on the surface of a substrate using an ozone solution in which ozone gas is dissolved in an organic acid aqueous solution, wherein the concentration of the organic acid in the ozone solution is less than 5000 ppm. A method of removing a resist on a substrate surface by supplying ozone water to a substrate, wherein the ozone water has a pH of 4 to 8, wherein the resist is removed. The method of claim 5, wherein the ozone water is obtained by dissolving ozone gas in an organic acid aqueous solution and having an organic acid concentration of less than 5000 ppm. 7. The resist removal method according to claim 5 or 6, wherein ozone water contains a reagent having a buffering effect of pH. The resist removal method according to any one of claims 5 to 7, wherein the ozone concentration of ozone water is 40 ppm or more. 9. The resist removal method according to any one of claims 1, 2 and 4 to 8, wherein the resist is a novolak-type resist. 10. The resist removal method according to any one of claims 1, 2 and 4 to 9, wherein the ozone solution is applied to the treated surface while irradiating ultraviolet rays.

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