KR101294019B1 - Composition for stripping photoresist and method of stripping photoresist using the same - Google Patents

Abstract

The photoresist removal composition is 80 to 98.5 wt% of γ-butyro lactone, 1 to 10 wt% of alkyl carbamate, 0.1 to 5 wt% of alkyl sulfonic acid and 0.1 to 5 wt% of nonionic surfactant It includes. The photoresist removal composition can be reused without substantial degradation in removal performance or damage to the metal pattern. Thus, the cost of the photolithography process can be reduced.

Photoresist, ozone

Description

Photoresist removal composition and photoresist removal method using the same {COMPOSITION FOR STRIPPING PHOTORESIST AND METHOD OF STRIPPING PHOTORESIST USING THE SAME}

1 is a flowchart illustrating a method of removing a photoresist according to an embodiment of the present invention.

2 is a schematic cross-sectional view showing a photoresist removal apparatus that can be used in the photoresist removal method according to an embodiment of the present invention,

3 and 4 are scanning electron microscope (SEM) photographs showing edge portions of a source electrode of a substrate to which a photoresist removing composition according to an embodiment of the present invention is applied,

5 and 6 are scanning electron microscope (SEM) photographs showing edge portions of gate lines of a substrate to which a photoresist removing composition according to an embodiment of the present invention is applied.

<Explanation of symbols for the main parts of the drawings>

10: photoresist removing device 17: conveyor

20: loading part 30: unloading part

100: chamber 102: first bath

104: second bath 106: third bath

107: first bath 108: second bulkhead

110: first tank 112: first discharge line

114: second discharge line 115: first nozzle

116: second nozzle 120: second tank

122: third discharge line 124: third nozzle

126: fourth nozzle 130: third tank

132: fifth nozzle 134: sixth nozzle

140: ozone reactor 145: ozone gas inlet

147: waste liquid outlet 150: degassing apparatus

155: nitrogen gas inlet 160: new liquid tank

The present invention relates to a photoresist removing composition and a photoresist removing method using the same, and more particularly, to a reusable photoresist removing composition and a photoresist removing method using the same.

A liquid crystal display displays an image using the optical and electrical properties of a liquid crystal material. The liquid crystal display device has advantages such as light weight, low power, low driving voltage and the like as compared with a CRT, a plasma display panel and the like.

Generally, a liquid crystal display device includes a liquid crystal display panel and a light source that supplies light to the liquid crystal display panel. The liquid crystal display panel includes a thin film transistor substrate, a color filter substrate, and a liquid crystal layer disposed between the substrates. Light generated from the light source passes through the liquid crystal layer, and the liquid crystal layer displays an image by adjusting the transmittance of the light.

The thin film transistor substrate includes a plurality of thin film transistors. The thin film transistors are formed through a photolithography process using a photoresist, and after the thin film transistor is formed, the photoresist removing composition is sprayed onto the substrate to remove residual photoresist. The photoresist removal composition may be collected and filtered through a filter and then partially reused.

However, when the photoresist removal composition is filtered with a filter to reuse the photoresist removal composition, it only serves to physically separate impurities in the photoresist removal composition, thereby removing the photoresist residue dissolved in the photoresist removal composition. It cannot be removed. As a result, there is a problem that the photoresist removal performance of the photoresist removal composition to be reused is lowered.

Accordingly, the technical problem of the present invention is to solve such a conventional problem, and to provide a reusable photoresist removing composition.

Another technical problem of the present invention is to provide a photoresist removing method using the photoresist removing composition.

The photoresist removal composition according to one aspect of the present invention is 80 to 98.5% by weight of Γ-butyro lactone, 1 to 10% by weight of alkyl carbamate, 0.1 to 5% by weight of alkyl sulfonic acid and nonionic 0.1 to 5 wt% of the surfactant.

The alkyl carbamate may comprise, for example, methyl carbamate.

The alkyl sulfonic acid may include, for example, at least one selected from the group consisting of methyl sulfonic acid, ethyl sulfonic acid, propyl sulfonic acid and butyl sulfonic acid.

The nonionic surfactant may include, for example, at least one selected from the group consisting of octylphenol ethoxylate and nonylphenol ethoxylate.

According to the photoresist removing method according to an aspect of the present invention, first, a photoresist removing composition is added to a photoresist formed on a substrate. The photoresist removal composition applied to the photoresist is recovered. Ozone gas is added to the recovered photoresist removal composition to decompose the photoresist impurities contained in the photoresist removal composition.

The photoresist removal composition prior to being applied to the photoresist comprises about 80 to about 98.5 weight percent of γ-butyro lactone, about 1 to about 10 weight percent of alkyl carbamate, about 0.1 to about 5 weight of alkyl sulfonic acid % And about 0.1 to about 5 weight percent of the nonionic surfactant.

After adding ozone gas to the photoresist removal composition, the photoresist removal composition may be degassed to remove ozone gas in the photoresist removal composition.

As described above, the cost of the photolithography process can be reduced by repeatedly reusing the photoresist removing composition without substantially degrading the removal performance or damaging the metal pattern.

Hereinafter, a photoresist removing composition according to an embodiment of the present invention will be described in detail.

Photoresist removal composition

The photoresist removal composition according to an embodiment of the present invention comprises about 80 to about 98.5 wt% of γ-butyro lactone, about 1 g to about 10 wt% of alkyl carbamate, about 0.1 alkyl sulfonic acid To about 5% by weight and about 0.1 to about 5% by weight of the nonionic surfactant.

As the alkyl carbamate, methyl carbamate, ethyl carbamate, propyl carbamate, butyl carbamate and the like may be used, and preferably methyl carbamate may be used.

As the alkyl sulfonic acid, methyl sulfonic acid, ethyl sulfonic acid, propyl sulfonic acid, butyl sulfonic acid, and the like may be used. Preferably, methyl sulfonic acid may be used.

The nonionic surfactant may include an ethylene oxide-based surfactant, and may specifically include octylphenol ethoxylate, nonylphenol ethoxylate, and the like, preferably octyl. Phenol ethoxylates can be used.

The photoresist removal composition according to the embodiment of the present invention has high photoresist decomposition performance and thus can be reused.

Hereinafter, a method of removing a photoresist according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

How to remove photoresist

1 is a flowchart illustrating a method of removing a photoresist according to an embodiment of the present invention.

According to the photoresist removing method according to an embodiment of the present invention, first, the photoresist removing composition is added to the photoresist formed on the substrate (S 10). The photoresist removing composition applied to the photoresist is recovered (S 20). Ozone gas is added to the recovered photoresist removing composition to decompose the photoresist impurities included in the photoresist removing composition (S30).

The photoresist removal composition prior to being applied to the photoresist comprises about 80 to about 98.5 weight percent γ-butyrolactone, about 1 to about 10 weight percent alkyl carbamate, about 0.1 to about 5 weight percent alkyl sulfonic acid and a nonionic surfactant About 0.1 to about 5 weight percent.

As the alkyl carbamate, methyl carbamate, ethyl carbamate, propyl carbamate, butyl carbamate and the like may be used, and preferably methyl carbamate may be used.

As the alkyl sulfonic acid, methyl sulfonic acid, ethyl sulfonic acid, propyl sulfonic acid, butyl sulfonic acid and the like may be used, and preferably methyl sulfonic acid may be used.

The nonionic surfactant may include an ethylene oxide surfactant. Specifically, the nonionic surfactant may include octylphenol ethoxylate, nonylphenol ethoxylate, and the like, and preferably, octylphenol ethoxylate.

Figure 2 is a schematic cross-sectional view showing a photoresist removal apparatus that can be used in the photoresist removal method according to an embodiment of the present invention. Specifically, the photoresist removing apparatus is an example of equipment suitable for the practice of the present invention, and is substantially the same as the photoresist removing apparatus disclosed in Korean Patent Application No. 2006-0103036, which is the applicant's patent application.

Referring to FIG. 2, the photoresist removing apparatus 10 includes a chamber 100, a conveyor 17, a first tank 110, a second tank 120, a third tank 130, and an ozone reactor 140. , Degassing device 150 and new liquid tank 160.

The substrate P including the photoresist is transferred into the chamber 100 by the conveyor 17. The chamber 100 is divided into a first partition 107 and a second partition 108, and a plurality of baths, for example, a first bath 102 and a second bath 104. And the third bath 106. In addition, the chamber 100 may include first to sixth nozzles 115, 116, 124, 126, 132, and 134 for spraying the photoresist removing composition.

The conveyor 17 serves to supply the substrate P into the chamber 100. Preferably, the conveyor 17 allows the substrate P to pass through the inside of the chamber 100 with a predetermined slope. The substrate P may continuously move from the rod portion 20 that is initially seated through the chamber 100 to the unload portion 30 from which the substrate P is discharged. The substrate P may pass continuously through each bath, or may be stopped for a predetermined time in each bath while the photoresist removing composition is sprayed, and then moved to the next bath. The photoresist removing composition sprayed onto the substrate P flows down to the bottom of each bath by gravity.

When the conveyor 17 has a constant inclination from the rod part 20 to the unload part 30, the photoresist removing composition sprayed through the nozzle is brought into uniform contact with the substrate P to facilitate process control. . In addition, the photoresist removing composition may be prevented from remaining on the substrate due to sag of the substrate or the like.

When the chamber 100 includes a plurality of baths, photoresist removal is easy and it is possible to recover the photoresist removal composition by classifying according to the concentration of photoresist residues in the photoresist removal composition.

The conveyor 17 may be a roller-type conveyor 17 so that the liquid photoresist removing composition can be easily discharged, but in addition to this other transport that can move the substrate (P) in the chamber 100 Means may be used.

As a method of moving the substrate P inside the chamber 100 with a predetermined slope, there is a method of tilting the conveyor 17 itself at a predetermined angle with respect to the horizontal plane. Alternatively, a pedestal (not shown) having a constant tilt angle on the parallel conveyor can be used. The bottom surface of the pedestal is in contact with the conveyor, and the substrate P is in contact with the top surface of the pedestal. The pedestal may have a wedge shape so that the top surface of the pedestal is inclined.

In detail, the substrate P is moved to the first bath 102 of the chamber 100 by the rod part 20. The first bath 102 is defined by the chamber 100 wall and the first partition 107 and includes a first nozzle 115 and a second nozzle 116 that spray the photoresist removal composition.

The first nozzle 115 serves to inject a photoresist removing composition for removing the photoresist of the substrate P, and injects the photoresist removing composition perpendicular to the upper surface of the substrate P or at an angle. . The second nozzle 116 sprays the photoresist removing composition on the lower surface of the substrate P in order to remove the photoresist flowing down the lower surface of the glass substrate P. FIG. The injection amount of the second nozzle 116 may be smaller than the injection amount of the first nozzle 115.

The photoresist removing composition injected through the first nozzle 115 and the second nozzle 116 dissolves the photoresist formed on the substrate P and flows down to the bottom of the first bath 102, and a first discharge line. It is introduced into the first tank 110 through the (112).

The photoresist removing composition of the first tank 110 is mixed with the photoresist removing composition supplied from the second tank 120, and again, the first bath (1) through the first nozzle 115 and the second nozzle 116. 102 is sprayed to the substrate P.

 After the photoresist is first removed from the first bath 102, the substrate P moves to the second bath 104. The photoresist removing composition supplied from the second tank 120 is sprayed onto the substrate P. The second bath 104 includes a third nozzle 124 and a fourth nozzle 126 that spray the photoresist removing composition supplied from the second tank 120 onto the substrate P. The injection method of the third nozzle 124 and the fourth nozzle 126 is substantially the same as the first nozzle 115 and the second nozzle 116. However, since the injected photoresist removing composition is supplied from the second tank 120, it contains less impurities such as photoresist than the photoresist removing composition stored in the first tank 110.

The photoresist removing composition injected from the second bath 104 to the substrate P flows down to the bottom of the second bath 104 and through the first discharge line 112 to the first tank 110. Inflow.

After the photoresist is secondarily removed from the second bath 104, the substrate P moves to the third bath 106. The photoresist removing composition supplied from the third tank 130 is sprayed onto the substrate P. The third bath 106 includes a fifth nozzle 132 and a sixth nozzle 134 that spray the photoresist removing composition supplied from the third tank 130 onto the substrate P. The spraying method of the fifth nozzle 132 and the sixth nozzle 134 is substantially the same as the spraying method of the first nozzle 115 and the second nozzle 116 described above. However, since the injected photoresist removing composition is supplied from the third tank 130, it contains less impurities than the photoresist removing composition of the first tank 110 and the second tank 120. This is because the third tank 130 has a photoresist removal composition ozonated for reuse and a new photoresist removal composition supplied from the new liquid tank 160.

The chamber 100 of the photoresist removal apparatus includes three baths, but the number of baths may be increased or reduced as needed. The arrangement of the storage tank for storing the photoresist removal composition and the photoresist removal composition may be variously changed as necessary.

In the photoresist removing composition stored in the first tank 110, the photoresist removing composition injected from the first bath 102 to the substrate P is introduced through the first discharge line 112, and the second bath 103 is disposed. The photoresist concentration is relatively high since the photoresist removing composition injected into the substrate P is introduced through the second discharge line 114. A portion of the photoresist removal composition of the first tank 110 is sprayed to the substrate P through the first and second nozzles 115 and 116 of the first bath 102, and the rest is ozone reactor 140. Is discharged. When the photoresist residue concentration of the photoresist removing composition is higher than the reference, the photoresist residue is discharged through the waste liquid outlet 147 from the first tank 110 without being supplied to the ozone reactor 140.

The ozone reactor 140 serves to regenerate the photoresist removal composition by removing photoresist residues from already used photoresist removal compositions. Since the photoresist is an organic film and is removed through a chemical wet process by the photoresist removing composition, the photoresist is dissolved in the used photoresist removing composition. Although the used photoresist removal composition contains a certain amount of photoresist residue, it is possible to perform the function of removing the photoresist film again, but the substrate P is contaminated by impurities contained in the photoresist removal composition. As a result, the efficiency of removing the photoresist film becomes low.

Therefore, in the present invention, ozone gas is used to remove organic substances in the photoresist removing composition used. Ozone is a more powerful oxidant than hydrogen peroxide and does not produce new reactants in solution.

The ozone reactor 140 includes a space for accommodating the photoresist removing composition used therein and includes an ozone gas injection hole 145 for supplying ozone gas to the photoresist removing composition.

When ozone gas is added to the photoresist removal composition comprising the photoresist residue, the photoresist residues dissolved or dispersed in the photoresist removal composition are decomposed into organic acids, producing carbon dioxide (CO₂) and / or water (H₂O). do. Since the ozone gas has a solubility of several to several tens of times that of oxygen gas, when the photoresist removing composition is passed in a gas state, the ozone gas may react with the photoresist residue of the photoresist removing composition relatively easily. When the photoresist removal composition is reused, the organic acids remaining in the photoresist removal composition may act as an additive to increase photoresist removal efficiency.

The degassing device 150 serves to remove ozone remaining in the ozone treated photoresist removal composition. Although ozone may dissolve the organic film, the efficiency of photoresist removal may be improved. However, ozone acts as a powerful oxidizing agent, so that when the photoresist removal composition containing residual ozone is sprayed onto the substrate, the substrate may be damaged. . Therefore, it is desirable to remove residual ozone from the regenerated photoresist removal composition.

The degassing apparatus 150 includes a space for receiving the ozone-treated photoresist removing composition in the ozone reactor 140 and includes a nitrogen gas inlet 155 for supplying nitrogen gas. When nitrogen gas is supplied into the photoresist removing composition containing ozone, ozone is decomposed to generate oxygen gas (O 2) and water.

The regenerated photoresist removal composition is supplied to the third tank 130 through the recovery line 170, and mixed with the new photoresist removal composition supplied from the new liquid tank 160 as necessary to the third bath 106. ) Is sprayed onto the substrate P. Therefore, the substrate P is cleaned by a photoresist removing composition containing relatively few impurities before being discharged to the unloading portion 30.

The photoresist removing method according to an embodiment of the present invention can reduce the manufacturing cost of the electronic device by adding ozone gas to the used photoresist removing composition to reuse the photoresist removing composition. The photoresist removal composition does not substantially degrade performance even when reused, and does not damage the metal pattern.

The photoresist removal method according to an embodiment of the present invention may be used not only for manufacturing a flat panel display (FPD) such as a liquid crystal display, but also for manufacturing a memory semiconductor substrate. It can also be used to fabricate other electronic devices manufactured using photolithography processes.

Hereinafter, a photoresist removing composition according to an embodiment of the present invention will be described through specific examples and experimental examples.

Example 1

A photoresist removal composition was prepared by mixing about 93 wt% of γ-butyrolactone, about 5 wt% of methyl carbamate, 1 wt% of methyl sulfonic acid, and about 1 wt% of op-10 as an ethylene oxide based surfactant.

Experimental Example 1 Evaluation of Photoresist Degradation Performance

A photoresist in powder was mixed with the photoresist removing composition of Example 1 and stirred to prepare a first solution having a photoresist content of about 72% by weight based on the total weight. The mixed solution was placed in a reactor and after 3 hours from the time when the ozone gas was added while the ozone gas was added, the respective photoresist content was measured after 5 hours. Next, a photoresist in powder form was again mixed with the mixed solution and stirred to prepare a second solution having a photoresist content of about 90% by weight based on the total weight. The photoresist content was measured after about 3 hours after the addition of ozone gas while adding ozone gas to the mixed solution. The results thus obtained are shown in Table 1 below. In addition, the decomposition rate (= (photoresist content after -5 hours) / initial photoresist content) of each of the first solution and the second solution was calculated from the obtained results, and is shown in Table 1 below.

Table 1

Measurement time (h) Photoresist content (% by weight) 5 hours decomposition rate (%)
First solution 0 72
79 3 25 5 15
Second solution 0 90
63 3 36 5 33

Referring to Table 1, it can be seen that when ozone is added to the photoresist removing composition of Example 1, the photoresist is decomposed relatively quickly. In addition, it can be seen that the second solution in which the photoresist is mixed with the ozone treated photoresist removing composition again has a relatively excellent photoresist decomposition performance.

The initial photoresist content of Table 1 is set higher than the photoresist concentration of the photoresist removing composition used in the actual process to confirm the photoresist decomposition performance of the photoresist removing composition according to the embodiment of the present invention. Therefore, the photoresist removal composition according to the embodiment of the present invention may have excellent performance even in the actual photoresist removal process.

Experimental Example 2-Evaluation of Photoresist Removal Performance

3 and 4 are scanning electron microscope (SEM) photographs showing edges of a source electrode of a substrate to which a photoresist removing composition according to an embodiment of the present invention is applied. Specifically, FIG. 3 is a photograph showing an edge of a source electrode of a substrate to which a first solution subjected to ozone treatment for 5 hours in Example 1, and FIG. 4 is a second solution subjected to ozone treatment for 5 hours to Example 1 It is a photograph which shows the edge of the source electrode of a board | substrate.

In order to evaluate the photoresist removing performance of the photoresist removing composition according to an embodiment of the present invention, a substrate on which a metal layer was formed was prepared. A photoresist layer having a thickness of about 2 μm was formed on the metal layer, and the photoresist layer was exposed and developed to form a photoresist pattern. Next, the drain electrode and the source electrode of the thin film transistor were formed using the photoresist pattern as a mask.

In Example 1, after degassing the first solution treated for 5 hours, a portion of the substrate was sprayed for about 30 seconds. In addition, after degassing the second solution ozone treated for 5 hours in Example 1, it was sprayed for the remaining part of the thin film transistor substrate for about 30 seconds.

3 and 4, it can be seen that the photoresist removal composition according to the embodiment of the present invention does not form a residue even when reused, and has excellent photoresist removal performance.

Experimental Example 3-Evaluation of Stability of Photoresist Removal Composition

5 and 6 are scanning electron microscope (SEM) photographs showing edge portions of gate lines of a substrate to which a photoresist removal composition according to an embodiment of the present invention is applied. Specifically, FIG. 5 is a photograph showing a gate line of a substrate to which the first solution is ozone treated for 5 hours in Example 1, and FIG. 6 is a diagram of a substrate to which the second solution is ozone treated to Example 5 for 5 hours. It is a photograph showing a gate line.

In order to evaluate the photoresist removing performance of the photoresist removing composition according to an embodiment of the present invention, a substrate on which a metal layer was formed was prepared. A photoresist layer having a thickness of about 2 μm was formed on the metal layer, and the photoresist layer was exposed and developed to form a photoresist pattern. Next, the gate line including the gate electrode was formed using the photoresist pattern as a mask.

After degassing the first solution, which was ozone treated in Example 1 for 5 hours, a portion of the substrate was sprayed for about 30 minutes. In addition, after degassing the second solution treated with ozone for 5 hours in Example 1, it was sprayed on the remaining portion of the thin film transistor substrate for about 30 minutes.

5 and 6, it can be seen that the photoresist removal composition according to the embodiment of the present invention does not damage the metal pattern even when reused.

According to the present invention, it is possible to reduce the cost of the photolithography process by repeatedly reusing the photoresist removal composition without substantial degradation of the removal performance or damage to the metal pattern.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (9)

γ-butyro lactone 80 to 98.5 wt%; 1 to 10 weight percent alkyl carbamate; 0.1 to 5 wt% alkyl sulfonic acid; And A photoresist removal composition comprising 0.1 to 5% by weight of nonionic surfactant. The photoresist removing composition of claim 1, wherein the alkyl carbamate comprises methyl carbamate. The photoresist removing composition of claim 1, wherein the alkyl sulfonic acid comprises at least one selected from the group consisting of methyl sulfonic acid, ethyl sulfonic acid, propyl sulfonic acid, and butyl sulfonic acid. The photoresist removing composition of claim 1, wherein the nonionic surfactant comprises at least one selected from the group consisting of octylphenol ethoxylate and nonylphenol ethoxylate. A photoresist comprising 80 to 98.5 wt% of γ-butyrolactone, 1 to 10 wt% of alkyl carbamate, 0.1 to 5 wt% of alkyl sulfonic acid, and 0.1 to 5 wt% of nonionic surfactant in the photoresist pattern formed on the substrate Adding a resist removal composition; Recovering the photoresist removal composition applied to the photoresist pattern; And Adding ozone gas to the recovered photoresist removal composition to decompose the photoresist impurities included in the photoresist removal composition. 6. The method of claim 5, further comprising removing ozone gas in the photoresist removal composition by degassing the photoresist removal composition after applying ozone gas to the photoresist removal composition. 6. The method of claim 5, wherein said alkyl carbamate comprises methyl carbamate. 6. The method of claim 5, wherein said alkyl sulfonic acid comprises at least one selected from the group consisting of methyl sulfonic acid, ethyl sulfonic acid, propyl sulfonic acid and butyl sulfonic acid. 6. The method of claim 5, wherein the nonionic surfactant comprises at least one selected from the group consisting of octylphenol ethoxylate and nonylphenol ethoxylate.

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