A cleaning solution for removing photoresist residues

Abstract

The present invention provides a cleaning solution for removing photoresist residues, comprising: quaternary ammonium hydroxide, alcohol amine, water, defoamer, and organic solvent. After adding the defoamer, the cleaning solution of the present application can not only efficiently remove the photoresist residues on the wafer, but also has substantially no corrosion to metals such as copper and aluminum, and basically does not foam, and can also extend the service life of the cleaning solution. It has good application prospects in the fields of semiconductor wafer cleaning and the like.

Description

Technical Field

[0001] The invention relates to a cleaning liquid for removing photoresist residues. Background Art

[0002] In the usual semiconductor manufacturing process, a photoresist mask is formed on the surface of some materials, and the pattern is transferred after exposure. After obtaining the required pattern, the remaining photoresist needs to be stripped off before the next process. In this process, it is required to completely remove the unnecessary photoresist without corroding any substrate.

[0003] At present, photoresist stripping liquid is mainly composed of polar organic solvents, strong alkali and / or water, and the photoresist on the semiconductor wafer is removed by immersing the semiconductor wafer in the stripping liquid or washing the semiconductor wafer with the stripping liquid. For example, JP1998239865 discloses a water-containing stripping liquid, which is composed of tetramethylammonium hydroxide (TMAH), dimethyl sulfoxide (DMSO), 1,3-dimethyl-2-imidazolidinone (DMI) and water. The wafer is immersed in the stripping liquid, and the photoresist of more than 20 μm on the metal and dielectric substrates is removed at 50-100°C; the corrosion of the semiconductor wafer substrate is slightly higher, and the photoresist on the semiconductor wafer cannot be completely removed, and the cleaning ability is insufficient; for example, US5529887 discloses an alkaline stripping liquid composed of potassium hydroxide (KOH), alkyl glycol monoalkyl ether, water-soluble fluoride and water, and the wafer is immersed in the stripping liquid to remove the photoresist on the metal and dielectric substrates at 40-90°C. The stripping solution has a high corrosion effect on the semiconductor wafer substrate. For example, WO2006 / 056298A1 uses an alkaline stripping solution composed of tetramethylammonium hydroxide (TMAH), dimethyl sulfoxide (DMSO), ethylene glycol (EG) and water to clean 50-100 micron thick photoresist, while having little corrosion to metal copper.

[0004] There is another common cleaning defect of the cleaning fluid. As the cleaning time increases, more and more photoresist dissolves in the cleaning fluid, which will produce a large amount of foam, causing the foam to overflow the cleaning machine. This affects the service life and cleaning performance of the photoresist cleaning fluid.

[0005] Therefore, it can be seen that finding a low-foaming, long-life photoresist cleaning solution is the priority direction for improving this type of photoresist cleaning solution. It is necessary to develop a cleaning solution with strong photoresist removal ability, low metal corrosion rate and long service life. Summary of the invention

[0006] In order to solve the problem that the cleaning solution for removing photoresist residues in the prior art cannot simultaneously take into account good photoresist removal effect, low metal corrosion rate, less foam, long cleaning solution service life, and wide use temperature range, as the cleaning time increases, the more photoresist is dissolved in the cleaning solution, and it is easy to generate foam overflowing the cleaning machine during cleaning, thereby affecting the service life of the cleaning solution. The present invention provides a cleaning solution for removing photoresist residues, comprising: quaternary ammonium hydroxide, alcohol amine, water, a defoaming agent, and an organic solvent.

[0007] Furthermore, the quaternary ammonium hydroxide is one or more of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, hexadecyltrimethylammonium hydroxide, and benzyltrimethylammonium hydroxide.

[0008] Furthermore, the alcoholamine is one or more of monoethanolamine, N-methylethanolamine, diethanolamine, triethanolamine, isopropanolamine, ethyldiethanolamine, N,N-diethylethanolamine, N-(2-aminoethyl)ethanolamine, and diglycolamine.

[0009] Furthermore, the alcoholamine is monoethanolamine and / or triethanolamine.

[0010] Furthermore, the defoaming agent is one or more of hydroxyl-containing polyether, polyvinyl alcohol, polyvinyl pyrrolidone, polyoxyethylene, polysiloxane, fluoropolyvinyl alcohol, fluoropolyvinyl pyrrolidone, fluoropolyoxyethylene, fluoropolysiloxane, and alkyl sulfonate.

[0011] Furthermore, the organic solvent is one or more of sulfoxide, sulfone, imidazolidinone, pyrrolidone, imidazolinone, amide, and alcohol ether.

[0012] Furthermore, the sulfoxide is dimethyl sulfoxide and / or methyl ethyl sulfoxide.

[0013] Furthermore, the sulfone is methyl sulfone and / or sulfolane.

[0014] Furthermore, the imidazolidinone is one or more of 2-imidazolidinone, 1,3-dimethyl-2-imidazolidinone, N-methylpyrrolidone, and N-cyclohexylpyrrolidone.

[0015] Furthermore, the imidazolidinone is 1,3-dimethyl-2-imidazolidinone.

[0016] Furthermore, the amide is dimethylformamide and / or dimethylacetamide.

[0017] Furthermore, the water is deionized water.

[0018] Furthermore, the concentration range of the quaternary ammonium hydroxide is 0.1-6%.

[0019] Furthermore, the concentration of the alcohol amine is in the range of 0.1-50%, preferably 5-40%.

[0020] Furthermore, the concentration of the water is in the range of 0.1-10%, preferably 0.5-6%.

[0021] Furthermore, the concentration of the defoaming agent is in the range of 0.0001%-3%, preferably 0.001-0.3%.

[0022] Furthermore, the concentration of the organic solvent is in the range of 48-94%, preferably 49-88%.

[0023] The % in the above concentration ranges are all mass percentages.

[0024] The reagents and raw materials used in the present invention are all commercially available. The cleaning solution of the present invention can be prepared by simply mixing the above components evenly.

[0025] Compared with the prior art, the advantages of the present invention are:

[0026] 1. After adding defoaming agent, the cleaning liquid of the present application can not only efficiently remove the photoresist residue on the wafer, but also has no corrosion to metals such as copper and aluminum, and basically does not foam, and can extend the service life of the cleaning liquid. It has good application prospects in the fields of semiconductor wafer cleaning.

[0027] 2. The cleaning solution of the present application can clean the photoresist residue on the wafer at 25°C to 80°C. The specific method is as follows: immerse the wafer containing the photoresist residue in the cleaning solution of the present invention, soak it at 25°C to 80°C for a suitable time, take it out, rinse it, and blow it dry with high-purity nitrogen. DETAILED DESCRIPTION

[0028] The advantages of the present invention are described in detail below in conjunction with specific embodiments.

[0029] Example

[0030] The cleaning solutions of the various embodiments of the present application and the cleaning solutions of the comparative examples were prepared according to the components and concentrations in Table 1, and were mixed evenly to a mass percentage of 100%.

[0031] Table 1. Components and concentrations of various examples and comparative examples

[0032]

[0033]

[0034]

[0035]

[0036] Effect Example

[0037] In order to further investigate the cleaning condition of the cleaning solution of the present application, the present invention adopts the following technical means: the wafer containing photoresist residues after the convex balls have been electroplated in the wafer microsphere implantation process is immersed in the cleaning solution of the present application embodiment and the cleaning solution of the comparative example in Table 1 respectively, and oscillates at a vibration frequency of about 60 rpm at 25°C to 80°C using a constant temperature oscillator for 30 to 120 minutes, and then rinses and blows dry with high-purity nitrogen. Observe the cleaning effect of the photoresist residues and the corrosion of the cleaning solution on the wafer; dissolve 6% photoresist in the cleaning solution and observe the foaming condition of the cleaning solution. The cleaning results are shown in Table 2.

[0038] Table 2: Metal corrosion, wafer cleaning and blistering of comparative examples and some examples

[0039]

[0040]

[0041]

[0042] From the cleaning effects of Examples 1-16 and Comparative Examples 7-1 to 7-5 in Table 2, it can be seen that the cleaning solution of the present invention has a good cleaning effect (strong photoresist removal ability) on wafers containing photoresist residues after the convex balls have been electroplated in the wafer microsphere implantation process, and has a wide operating temperature range (25°C-80°C), basically no foaming, a long cleaning solution service life, and a low corrosion rate for metal aluminum and copper.

[0043] From Comparative Example 7-1 and Example 7, it can be seen that when phenethyl oleate is used as a defoaming agent and added to the cleaning solution, and other components are the same and the operating conditions are the same, although there is no obvious difference in the cleaning effect of the two on metal copper corrosion and photoresist, and no obvious foam appears when 6% photoresist is added to the cleaning solution; however, metal aluminum is corroded. Comparative Example 7-1 does not protect metal aluminum as well as Example 7; in other words, the cleaning solution of the present application has a low corrosion rate on aluminum and copper.

[0044] Comparison between Comparative Example 7-2 and Example 7: Dimethyl silicone oil was used as a defoaming agent in the cleaning solution. Under the same other components and operating conditions, although no significant difference was observed between the two in terms of metal aluminum corrosion and metal copper corrosion, and no obvious foam appeared when 6% photoresist was added to the cleaning solution, the removal effect of the photoresist was affected. The removal effect of the photoresist in Comparative Example 7-2 was not as good as that in Example 7; in other words, the cleaning solution of the present application has excellent photoresist removal ability.

[0045] Comparison between Comparative Examples 7-3, 7-4 and Example 7: Polyoxyethylene polyoxypropylene pentaerythritol ether and polyether modified silicon were used as defoaming agents and added to the cleaning solution. Under the same other components and operating conditions, although there was no obvious difference in the removal effects of Comparative Examples 7-3 and 7-4 on metal aluminum corrosion, metal copper corrosion and photoresist, when 6% photoresist was added to the cleaning solutions of Comparative Examples 7-3 and 7-4, more foam appeared when gently shaken. After standing for 5 minutes, the foam did not disappear. No foam appeared in Example 7 when gently shaken.

[0046] Comparative Examples 7-3 and 7-4 were placed together with Example 7 for 24 hours, 48 ​​hours, and 72 hours to observe the foaming. As the placement time of Comparative Examples 7-3 and 7-4 increased, more foam appeared after gently shaking, and the foam did not disappear after standing for 5 minutes; however, as the placement time of Example 7 increased, no foam appeared after gently shaking. The defoaming agent added to Comparative Examples 7-3 and 7-4 did not have as good a defoaming effect as Example 7. The cleaning solution of the present application has the characteristic of being basically non-foaming.

[0047] Comparison between Comparative Example 7-5 and Example 7: When no defoaming agent was used in the cleaning solution and other components were the same and the operating conditions were the same, although no obvious difference was seen in the removal effects of Comparative Example 7-5 on metal aluminum corrosion, metal copper corrosion and photoresist, 6% photoresist was added to the cleaning solution of Comparative Example 7-5, a large amount of foam appeared after gentle shaking, and the foam did not disappear after standing for 5 minutes. Comparative Example 7-5 and Example 7 were placed at the same time for 24 hours, 48 ​​hours, and 72 hours to observe the foaming situation. As the placement time of Comparative Example 7-5 increased, more foam appeared after gentle shaking, and the foam did not disappear after standing for 5 minutes; however, as the placement time of Example 7 increased, no foam appeared after gentle shaking.

[0048] In summary, the cleaning solution of the present invention effectively removes the photoresist residues on the wafer while having substantially no corrosion to the substrate such as metal aluminum, copper, etc. The addition of a defoamer to the cleaning solution does not affect the removal of the photoresist residues on the wafer, nor does it affect the corrosion rate of metals such as copper and aluminum. The addition of a defoamer to the cleaning solution can extend the service life of the cleaning solution. It has good application prospects in the fields of semiconductor wafer cleaning and the like. It has good application prospects in the fields of semiconductor wafer cleaning and the like.

[0049] The specific embodiments of the present invention are described in detail above, but they are only examples, and the present invention is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications and substitutions made to the present invention are also within the scope of the present invention. Therefore, the equalization changes and modifications made without departing from the spirit and scope of the present invention should be included in the scope of the present invention.

Claims

1. A cleaning solution for removing photoresist residues, characterized in that: include: Quaternary ammonium hydroxide, alcohol amine, water, defoaming agent, and organic solvent; The defoaming agent is one or more of polyvinyl alcohol, polyvinyl pyrrolidone, polyoxyethylene, fluoropolyvinyl alcohol, fluoropolyvinyl pyrrolidone, fluoropolyoxyethylene, fluoropolysiloxane, and alkyl sulfonate; The quaternary ammonium hydroxide is one or more of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, hexadecyltrimethylammonium hydroxide and benzyltrimethylammonium hydroxide; The alcohol amine is one or more of monoethanolamine, N-methylethanolamine, diethanolamine, triethanolamine, isopropanolamine, ethyldiethanolamine, N,N-diethylethanolamine, N-(2-aminoethyl)ethanolamine, and diglycolamine; The concentration range of the quaternary ammonium hydroxide is 0.1-6%; The concentration range of the alcohol amine is 0.1-50%; The concentration range of the water is 0.1-10%; The concentration range of the defoamer is 0.0001%-3%; The concentration of the organic solvent ranges from 48-94%.

2. The cleaning solution for removing photoresist residues as claimed in claim 1, characterized in that: The alcoholamine is monoethanolamine and / or triethanolamine.

3. The cleaning solution for removing photoresist residues as claimed in claim 1, characterized in that: The organic solvent is one or more of sulfoxide, sulfone, imidazolidinone, pyrrolidone, imidazolinone, amide, and alcohol ether.

4. The cleaning solution for removing photoresist residues as claimed in claim 3, characterized in that: The sulfoxide is dimethyl sulfoxide and / or methyl ethyl sulfoxide.

5. The cleaning solution for removing photoresist residues as claimed in claim 3, characterized in that: The sulfone is methyl sulfone and / or sulfolane.

6. The cleaning solution for removing photoresist residues as claimed in claim 3, characterized in that: The imidazolidinone is one or more of 2-imidazolidinone, 1,3-dimethyl-2-imidazolidinone, N-methylpyrrolidone and N-cyclohexylpyrrolidone.

7. The cleaning solution for removing photoresist residues as claimed in claim 3, characterized in that: The imidazolidinone is 1,3-dimethyl-2-imidazolidinone.

8. The cleaning solution for removing photoresist residues as claimed in claim 3, characterized in that: The amide is dimethylformamide and / or dimethylacetamide.

9. The cleaning solution for removing photoresist residues as claimed in claim 1, characterized in that: The water is deionized water.

10. The cleaning solution for removing photoresist residues according to claim 1, characterized in that: The concentration of the alcoholamine is in the range of 5-40%.

11. The cleaning solution for removing photoresist residues according to claim 1, characterized in that: The concentration of the water is in the range of 0.5-6%.

12. The cleaning solution for removing photoresist residues according to claim 1, characterized in that: The concentration range of the defoamer is 0.001-0.3%.

13. The cleaning solution for removing photoresist residues according to claim 1, characterized in that: The concentration range of the organic solvent is 49-88%.

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