KR101384810B1 - Thinner for rinsing photoresist and the method of purifying the thinner - Google Patents

Abstract

The present invention relates to a thinner composition for rinsing photoresist and a purifying method thereof, and more specifically, to a thinner composition for rinsing photoresist and a purifying method thereof, wherein an existing thinner with a single component can be substituted with a mixed thinner. The thinner composition improves economical efficiency and user convenience by improving yield and processing convenience.

Description

Thinner composition for photoresist rinsing and its purification method {Thinner for rinsing photoresist and the method of purifying the thinner}

The present invention relates to a thinner composition for photoresist rinsing and a method for purifying the same, and more specifically, to a conventional thinner thinner, which can be replaced with a thinner of a mixed solvent, at the same time high yield and convenience of work process at the time of regeneration. The present invention relates to a thinner composition and a method for purifying the same, which can be improved to maximize economics and convenience in an industrial aspect.

BACKGROUND ART [0002] Lithography is widely used to manufacture electronic circuits, pixels, and the like in a manufacturing process of a display such as a semiconductor and a TFT-LCD. Such a lithography is a method used for producing a fine pattern on a substrate, in which a substrate on which a photoresist as a photosensitive material is applied is irradiated with light through a mask having a desired pattern printed thereon to transfer a circuit pattern of the mask onto a substrate And the photoresist is generally composed of a binder component such as a resin, a photoinitiator, an organic solvent, various pigments, a dispersant, and other additives.

Specifically, the photolithography process in the manufacturing process of the semiconductor device, by applying the photosensitive resin composition on the wafer, transfer the pre-designed pattern and then configure the electronic circuit through the etching process appropriately according to the transferred pattern It's work. The photolithography process includes a coating process for uniformly applying the photosensitive resin composition to the surface of the wafer, a soft baking process for evaporating the solvent from the coated photosensitive film to attach the photosensitive film to the surface of the wafer, and a light source such as ultraviolet light. The photosensitive film is exposed by repeatedly and sequentially reducing and projecting the circuit pattern on the mask to transfer the mask pattern onto the photosensitive film, and the physical properties such as the difference in solubility vary depending on the exposure to the light source. A development step of selectively removing the developed portions using a developing solution, a hard baking process to more closely adhere the photoresist film remaining on the wafer to the wafer after the development work, and a pattern of the developed photoresist film. Etching process to etch certain parts and unnecessary after the process It proceeds to the rinse process etc. which the thinner which removes a photosensitive film is used.

In the photolithography process, photoresist may be applied to a portion of the photoresist coating nozzle, a coating peripheral device, or an edge of the substrate, which may cause a defect in a subsequent photoresist coating process and must be removed.

At this time, a thinner composition is used to remove unwanted photoresist. As a conventional thinner solvent, it was common to use a single component among solvents belonging to ethers, ketones, and esters, but recently, the thinner solvent is suitable for the purpose of use of thinners, and the mixed solvent thinner is emphasized as safety and volatility for human body and fire are emphasized. Increasingly, they develop and use them.

As an example, Japanese Patent Application Laid-Open No. 7-146562 has developed a mixed solvent thinner of propylene glycol alkyl ether and alkyl 3-alkoxypropionate. Japanese Patent Laid-Open No. 7-128847 discloses propylene glycol alkyl ether, butyl acetate, and ethyl lac. Tate mixtures and the like have been developed as thinners.

The waste liquid from which the photoresist is removed in the rinsing process includes impurities from the previous step of the rinsing process in addition to the components of the thinner.

Such waste liquid contaminated with impurities may be incinerated, but harmful chemicals are generated during incineration.

On the other hand, the conventional thinner composition is propylene glycol monomethylether acetate (PMA) as a main component, MMP (methyl 3-methoxypropio) generated in the photoresist, etching solution, etc. of the previous step when washed with the thinner during the rinsing process Nate, Methyl 3-methoxypropionate), n-BA (normal butyl acetate), PMA and the like are additionally included in the waste solution, the boiling point of the components are as follows.

ingredient PMA n-BA MMP Boiling point 146 ℃ 127 ℃ 143 ℃

In order to recycle the waste liquid, PMA should be recovered by fractional distillation using a difference in boiling point. However, MMPs contained in the waste liquid have similar boiling points to PMA, and thus, various operations for differentiating boiling points of other components in recovering PMA. Due to this, the recovery of PMA is considerably low, about 80% or less, and the boiling point is relatively high compared to other components, resulting in a lot of energy, which is a waste of energy.

In addition, PMA and MMP are relatively expensive and can be replaced, as well as thinners that can reduce the defect rate of the process by minimizing blockages (bleaching) in the spray nozzles spraying the thinner composition as well as the etchant. A composition is needed.

The present invention has been made to solve the above problems, the problem to be solved by the present invention is to use azeotropic distillation in recycling the thinner used in the photoresist process photoresist to increase the recovery rate of the thinner composition in the waste liquid It is to provide a thinner composition for rinse and a purification method thereof.

In addition, the present invention provides a thinner composition and a method for purifying the thinner composition which can reduce the convenience and manufacturing cost of the work process by making the purification process simple by using azeotropic distillation.

The present invention also provides a thinner composition for photoresist rinsing and a method of purifying the thinner composition by using a thinner composition having a low boiling point in the optimal composition ratio in purifying waste liquid.

The present invention also provides a thinner composition for photoresist rinsing and a method for purifying the same, which can minimize clogging in the injection nozzles to which the thinner composition is sprayed.

The present invention also provides a thinner composition for photoresist rinsing and a method for purifying the same, which can include economically inexpensive components as a main component.

Furthermore, the present invention provides a thinner composition for photoresist rinsing and purification thereof, in which the impurities can be used as components of the purified thinner rather than separating impurities from the waste liquid recovered after the rinsing process of the photolithography process to further increase the recovery rate. To provide a way.

The problem to be solved of the present invention is not limited to the technical problem mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

The present invention may include the following means to solve the problem to be solved.

Purification method of the thinner composition for photoresist rinsing according to an embodiment of the present invention is an azeotropic distillation step of azeotropic distillation is formed by azeotropes in the waste liquid and the separation step and the separation step of removing water from the azeotropic distillation mixture A re-injection step of re-inserting the water-removed component into the waste liquid, a first distillation step of distilling the waste liquid after the re-injection step, and a second distillation step of distilling the waste liquid after the first distillation step; A thinner composition is formed, including a cooling step of liquefying the waste liquid after the second distillation step.

The method of purifying the thinner composition for photoresist rinsing further includes a replenishing step of replenishing the ingredients to the thinner composition which has undergone the cooling step.

The azeotropic distillation step is characterized in that at a lower temperature than the first distillation step.

The second distillation step is characterized in that at a higher temperature than the first distillation step.

The waste liquid is characterized by containing propylene glycol methyl ether, normal butyl acetate, methyl-3-methoxypropionate and water.

The azeotrope is characterized in that it is formed by containing normal butyl acetate and water.

The azeotropic distillation step is characterized in that it is made at 87 ~ 95 ℃.

The first distillation step is characterized in that at 110 ~ 130 ° C.

The second distillation step is characterized in that made at 135 ~ 143 ℃.

The component to be supplemented in the replenishment step is characterized in that it comprises one or more components selected from propylene glycol methyl ether, normal butyl acetate, methyl-3-methoxypropionate, propylene glycol monomethyl ether acetate.

The thinner composition for photoresist rinsing according to another embodiment of the present invention is purified by any of the above methods.

The thinner composition for photoresist rinse is 89 to 95% by weight of propylene glycol methyl ether, 1 to 5% by weight of normal butyl acetate, 3 to 8% by weight of methyl-3-methoxypropionate, and propylene glycol mono in the total weight of the thinner composition. It is characterized in that it comprises 0.1 to 1% by weight of methyl ether acetate.

The present invention can increase the recovery rate of the thinner composition in the waste liquid by using azeotropic distillation in recycling the thinner used in the photoresist process.

In addition, the present invention can make the purification process simple by using azeotropic distillation can lower the convenience and manufacturing cost of the work process.

In addition, the present invention can use a minimum energy during purification due to the use of the thinner composition by the optimum boiling ratio of low boiling point in the purification of the waste liquid.

In addition, the present invention can minimize the clogging phenomenon in the injection nozzle is sprayed thinner composition.

In addition, the present invention may include a low cost component as a main component economically.

Furthermore, the present invention can further increase the recovery rate by allowing impurities to be used as components of the purified thinner rather than separating impurities from the waste liquid recovered after the rinsing process of the photolithography process.

1 is a G / C analysis result according to Example 1
2 is a G / C analysis result according to Example 2

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described in detail below. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

Hereinafter, the present invention will be described in detail.

Purification method of the thinner composition for a photoresist rinsing according to an embodiment of the present invention, comprises azeotropic distillation step, separation step, re-insertion step, primary distillation step, secondary distillation step and cooling step.

The azeotropic distillation step is a step in which azeotropic mixture is formed in the waste solution to azeotropic distillation. The waste liquid referred to in the present invention refers to one obtained after the rinsing process of photolithography, and the waste liquid is propylene glycol methyl ether (PGME), normal butyl acetate (n-BA), methyl-3-methoxypropionate (MMP). ), Propylene glycol monomethyl ether acetate (PMA), water and impurities are suitable to increase the recovery rate of the thinner during recycling.

In general, PMA, MMP, n-BA, moisture, etc. are used in the photosensitive process of the semiconductor or display is a material generated when washing with a thinner. The present invention can increase the recovery rate and prevent waste of resources that are utilized in the composition of the thinner without discarding such impurities.

The azeotropic mixture referred to in the present invention (azeotropic mixture) is a mixture of a solution state that can occur in azeotropic conditions, in general, when the solution distills, the composition changes as it boils, so that the boiling point is usually raised or lowered. However, certain types of liquids of a certain ratio boil unchanged at a constant temperature, like pure liquids, at which point the ratio of the solution and the vapor is the same. At this time, the system is in an azeotropic state, and the composition ratio is azeotropic, and the solution is azeotropic, and the boiling point of the azeotropic mixture is called azeotropic point. The azeotropic state changes with pressure, and the azeotropic point shows the minimum or maximum value on the boiling point curve representing the relationship between the component ratio and the boiling point.

On the other hand, the boiling point of PMA, PGME, MMP, n-BA, water is shown in Table 2.

ingredient PMA n-BA PGME MMP water Boiling point 146 ℃ 127 ℃ 116.1 ℃ 143 ℃ 100 ℃

The boiling points of PGME, n-BA, and water are similar and are difficult to separate into simple distillation. In addition, moisture is a component to be removed or minimized because it lowers the cleaning power of the thinner. Therefore, n-BA and water in the waste liquid can be formed as an azeotrope, and the boiling point of the azeotropes is preferably 87-95 ° C., lower than the boiling point of PGME so that the azeotrope can be azeotropically volatilized before PGME. do. The n-BA of the present invention is included as a thinner component of the present invention for the purpose of removing moisture as well as to prevent whitening of the thinner spray nozzle which will be described below.

The separation step is a step of removing water from the azeotropic distillation azeotropic distillation step in the azeotropic distillation step, the volatilized azeotrope through a known separator to remove the water.

The re-supply step is a step of re-injecting the component from which the water is removed, preferably n-BA, into the waste liquid which has undergone the azeotropic distillation step, so that the impurities generated in the photolithography process can be recycled again. The n-BA has an effect of removing moisture in the purification process, and when used as a composition of the thinner, the n-BA can reduce the clogging phenomenon of the spray nozzle of the thinner which will be described below.

On the other hand, the azeotropic distillation step, separation step and re-injection step may be repeated several times to remove the water of the waste liquid.

The first distillation step is a step of distilling the waste liquid after the re-entry step, preferably n-BA and PGME can be distilled and recycled at 110 ~ 130 ℃.

The second distillation step is a step of distilling the waste liquid after the first distillation step, preferably M135 is distilled at 135 ~ 143 ℃ and a small amount of PMA can be distilled and recycled. On the other hand, the boiling point of the PMA is 146 ℃ and the boiling point of the MMP is 143 ℃ boiling point is similar to each other in order to separate the PMA and MMP, but the present invention is required to be composed of the composition of the recycle thinner PMA and MMP This eliminates the need for an additional separation process.

The cooling step is a step of liquefying the gas containing the distilled components, preferably distilled n-BA, PGME, PMA, MMP after the second distillation step, thereby forming a thinner composition do.

On the other hand, the azeotropic distillation step is performed at a lower temperature than the first distillation step, and the second distillation step can be made at a higher temperature than the first distillation step, thereby purifying continuously by temperature without undergoing various operations. It is possible to increase the recovery rate of the thinner composition in the waste liquid due to the simple purification process, thereby lowering the convenience and manufacturing cost of the work process.

On the other hand, according to another embodiment of the present invention, the purification method of the thinner composition for photoresist rinse may further comprise a supplementing step. The replenishing step is a step of replenishing the thinner composition to the thinner composition after the cooling step, wherein the replenishing component is propylene glycol methyl ether, normal butyl acetate, methyl-3-methoxypropionate, propylene glycol monomethyl ether acetate It is suitable to include one or two or more components selected from. The replenishment component is preferably 3 to 9% by weight based on the total weight of the thinner composition. Since the thinner composition having a very high recovery rate of about 91 to 97% can be recovered by the purification method of the present invention, the insufficient components are replenished only by a small amount of about 3 to 9% through the component analysis of the thinner composition that has undergone the cooling step. This will allow the thinner composition to be fully recycled.

Meanwhile, the thinner composition for photoresist rinsing according to another embodiment of the present invention can be produced by the above methods.

The thinner composition for photoresist rinse is 89 to 95% by weight of propylene glycol methyl ether, 1 to 5% by weight of normal butyl acetate, 3 to 8% by weight of methyl-3-methoxypropionate, and propylene glycol mono in the total weight of the thinner composition. It is preferable to include 0.1 to 1% by weight of methyl ether acetate to increase the recovery rate of the thinner composition during the purification process.

In particular, the reason why the weight of propylene glycol methyl ether (PGME) is formed at 89 to 95% by weight based on the total weight of the thinner composition is that the boiling point is relatively methyl-3-methoxypropionate (MMP), propylene glycol monomethyl ether acetate (PMA). Lower than) and higher boiling point than the azeotrope of normal butyl acetate (n-BA) and water, the PGME can minimize the loss in the distillation step to increase the recovery rate of the thinner composition.

Meanwhile, the thinner composition includes MMP and n-BA as impurities in the photolithography process or as a component of the thinner composition without discarding the thinner composition. As a result, the thinner composition according to the present invention is sprayed in the rinsing process during the photolithography process. It is possible to prevent the whitening phenomenon, which is a clogging phenomenon of the injection nozzle, to form a more efficient recycle thinner composition.

In addition, the present invention is to include the PGME, a cost-effective component as a main component, and furthermore, rather than to separate the impurities such as n-BA, MMP, PMA in the waste liquid recovered after the rinsing process of the photolithography process It provides a thinner composition for rinsing photoresist and a method of purifying the same to be used as a component of the purified thinner to further increase the recovery rate.

Hereinafter, the contents of the present invention will be described in detail by way of examples. However, the scope of the present invention is not limited to these embodiments, but the present invention is not limited thereto.

[Example 1]

The waste liquid containing 450 g of PGME, 25 g of n-BA, 25 g of MMP, 2 g of PMA, and 2 g of water from the photolithography rinse process is azeotropically heated at 92 ° C. to remove water from the separator, and the water vapor is returned to the waste liquid. Let's do it. Thereafter, the waste liquid was distilled at 129 ° C., and finally distilled at 143 ° C. to obtain 475 g (yield: about 95%) of the distillate. The results of G / C analysis were as shown in FIG.

[Example 2]

The waste liquid containing 465 g, n-BA 25 g, MMP 10 g, PMA 2 g, and 2 g of water from the photolithography rinse process is azeotropically volatile at 92 ° C to remove the water from the separator and the water vapor is returned to the waste liquid. Let's do it. After that, the waste liquid was distilled at 129 ° C., and finally distilled at 143 ° C. to obtain 475 g (yield: 96%) of the distillate. The results of G / C analysis were as shown in FIG.

[Consideration 1]

As seen in Examples 1 and 2, the purification method as in the present invention was found to have a very high recovery rate.

[Example 3]

A photoresist thickness of 3.0 μm was dried at 140 ° C. for 5 minutes, and a dissolution test was performed on 100 g of distillates according to Examples 1 and 2 and 100 g of PMA as a comparative example.

The results are shown in Table 3 below.

Thinner Dissolution time Cleaning result Example 1 15 seconds Good Example 2 18 seconds Good Comparative Example 1 16 seconds Good

[Consideration 2]

Therefore, it was confirmed that the thinner composition according to the present invention is a thinner composition that can replace the existing PMA solvent.

Experimental Example 1 Recovery Rate Experiment

Example 4 to 6 and Comparative Examples 2 to 4 according to the weight ratio of n-BA, PGME of Tables 4 to 9 below were subjected to recovery experiments in the same manner as in Example 1.

Comparative Example 2 n-BA PGME MMP PMA moisture Recovery rate 10 84 3 One 2 G.C 14.3 82.35 2.36 One 2 Final product 9.712 89.93 0.27 0.08 0.05 79.1%

Comparative Example 3 nBA PGME MMP PMA moisture Recovery rate 30 64 3 One 2 G.C 39.44 57.39 2.21 0.95 2 Final product 36.08 63.67 0.19 0.06 0.04 76.9%

Comparative Example 4 nBA PGME MMP PMA moisture Recovery rate 50 44 3 One 2 G.C 60.30 36.85 2.01 0.84 2 Final product 55.69 44.05 0.21 0.046 0.04 67.7%

Example 4 nBA PGME MMP PMA moisture Recovery rate One 93 3 One 2 G.C 1.48 94.96 2.48 1.09 2 Final product 1.03 98.42 0.42 0.12 0.12 91.13%

Example 5 nBA PGME MMP PMA moisture Recovery rate 3 91 3 One 2 G.C 4.43 92.08 2.42 1.06 2 Final product 3.28 96.23 0.38 0.11 0.12 92.36%

Example 6 nBA PGME MMP PMA moisture Recovery rate 4 90 3 One 2 G.C 7.44 89.07 2.41 1.08 2 Final product 4.69 94.91 0.30 0.09 0.19 91.7%

Comparative Examples 2 to 4 have a low recovery rate, but in Examples 4 to 6, the content of PGME is higher than 89% by weight, and when the n-BA is 1 to 5% by weight, the recovery is found to be higher than 90%. It was.

Experimental Example: Whitening Prevention Experiment

The evaporation residue remaining after evaporation of the waste photoresist thinner contains various organic and inorganic substances, and the compound adheres to the spray nozzle, causing crystal growth to cause clogging (whitening). The evaporation residue was finely pulverized to homogenize the sample, 0.05 g of the sample was weighed, and dissolved in 2 ml of thinner composition having the component ratios (wt%) shown in the following table. Was calculated.

Example 7 Comparative Example 5 Comparative Example 6 Comparative Example 7 n-BA 3 0 7.5 0 PGME 92 92 92 99.5 MMP 4.5 7.5 0 0 PMA 0.5 0.5 0.5 0.5 Solubility (%) 22.4 18.4 10.6 7.4

As can be seen in Table 10, it is determined that the solubility of Example 7 according to the present invention is the highest so that the failure rate of the photolithography process can be reduced by preventing whitening.

Claims (13)

An azeotropic distillation step in which an azeotrope is formed in the waste solution and azeotropically distilled;
A separation step of removing water from the azeotropic distillation mixture;
A re-introduction step of re-injecting the component from which water is removed in the separation step into the waste liquid;
A first distillation step of distilling the waste liquid after the reinjection step;
A second distillation step of distilling the waste liquid after the first distillation step;
Forming a thinner composition including a cooling step of liquefying the distilled components after the second distillation step,
The waste liquid is propylene glycol methyl ether, normal butyl acetate, methyl-3- methoxy propionate and water purification method of thinner composition for rinsing, characterized in that containing water. The method of claim 1, wherein the purification method of the thinner composition for photoresist rinsing is
Purifying method of the thinner composition for a photoresist rinse characterized in that it further comprises a replenishment step of replenishing the ingredients to the thinner composition after the cooling step. The method according to claim 1,
The azeotropic distillation step is a purification method of the thinner composition for a photoresist rinse, characterized in that at a lower temperature than the first distillation step. The method according to claim 1,
The second distillation step is a purification method of the thinner composition for a photoresist rinse, characterized in that at a higher temperature than the first distillation step. delete The method of claim 1, wherein the azeotrope,
A method of purifying a thinner composition for photoresist rinsing, comprising normal butyl acetate and water. According to claim 1, The azeotropic distillation step,
The purification method of the thinner composition for photoresist rinse which consists of 87-95 degreeC. The method of claim 1, wherein the first distillation step,
Purification method of the thinner composition for photoresist rinse, characterized in that at 110 ~ 130 ° C. The method of claim 1, wherein the secondary distillation step,
The purification method of the thinner composition for photoresist rinse which consists of 135-143 degreeC. The method of claim 2, wherein in the replenishment step,
The component to be supplemented is a thinner composition for photoresist rinsing comprising one or more components selected from propylene glycol methyl ether, normal butyl acetate, methyl-3-methoxypropionate, and propylene glycol monomethyl ether acetate. Purification method. The method of claim 10, wherein the component to be supplemented,
A method for purifying a thinner composition for photoresist rinsing, wherein the thinner composition is supplemented with 3 to 9% by weight based on the total weight of the thinner composition. The thinner composition for photoresist rinsing purified by any one of Claims 1-4 and 6-11. The thinner composition of claim 12, wherein the thinner composition for photoresist rinsing is
89 to 95% by weight of propylene glycol methyl ether, 1 to 5% by weight of normal butyl acetate, 3 to 8% by weight of methyl-3-methoxypropionate, and 0.1 to 1% by weight of propylene glycol monomethyl ether acetate Thinner composition for a photoresist rinse, characterized in that it is included.

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