A water-based degumming solution for semiconductor manufacturing process

Abstract

The invention discloses a water-based degumming liquid for semiconductor manufacturing process, which is used in semiconductor wafer manufacturing. The water-based degumming liquid generates synergistic effect and synergistic effect by adding a specific compounded anionic nonionic surfactant, and optimizes the combination with a water-soluble organic additive, greatly improves the surface performance of the system, strengthens the swelling effect, and has a strong dissolving ability for small photoresist molecules, and has a high removal efficiency. At the same time, the water-based degumming liquid has good water solubility, low use temperature, long service life, low foam, little effect on product yield fluctuation, and the material composition is environmentally friendly, has little effect on human health, and can meet the process requirements of semiconductor manufacturing process.

Description

Technical Field

[0001] The invention belongs to the field of semiconductor manufacturing, and in particular relates to a water-based degumming solution used in semiconductor manufacturing processes. Background Art

[0002] In the semiconductor manufacturing process, the photolithography process is a key link in the chip manufacturing process. It is necessary to form multiple layers of fine circuit patterns on the silicon wafer through multiple processes such as pattern mask exposure and etching. The basic principle of photolithography is to use the characteristics of photoresist (or photoresist) to form corrosion resistance due to photochemical reaction after exposure to light, and to engrave the pattern on the mask onto the processed surface. When the etching process is completed, the photoresist should be completely removed, and this step is referred to as stripping. In order to avoid any damage and corrosion to the processed surface, mild chemical methods at low temperatures are generally used to remove the photoresist.

[0003] At present, the main water-based degumming liquid is prepared with sulfoxide, pyrrolidone, quaternary ammonium alkali and water in a certain proportion. Compared with the traditional organic solvent degumming liquid, it not only has cost advantages, but also has improved environmental protection and safety for operators. However, the current water-based degumming liquid still has the problems of low efficiency in removing photoresist, high operating temperature of the degumming liquid, short service life, easy corrosion to the metal layer, resulting in reduced yield, which seriously affects its use and promotion. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects in the prior art and provide a water-based degumming solution for semiconductor process. The water-based degumming solution is a water-soluble mixture. By adding a specific compound surfactant, the photoresist can be removed efficiently without residue. At the same time, the water-based degumming solution has low corrosion to the metal layer, long service life, and is green and environmentally friendly.

[0005] To achieve the above object, the technical solution of the present invention is:

[0006] A water-based degumming solution for semiconductor manufacturing process, which is composed of the following components in terms of mass percentage:

[0007] Alcoholamine solvent 10%-25%;

[0008] Water-soluble organic solvent 15%-25%;

[0009] Surfactant 5%-15%;

[0010] Metal resist 0.05%-0.5%;

[0011] Deionized water balance;

[0012] The total mass fraction sums up to 100%.

[0013] Furthermore, in the water-based degumming liquid for semiconductor manufacturing, the alcohol amine solvent is 2-methylamino-3-pyridinemethanol. The alcohol amine solvent can provide alkaline conditions for removing photoresist molecules, and its heterocyclic structure has similar miscibility with the photoresist molecular structure, can efficiently and quickly remove the photoresist molecules on the wafer at room temperature, and has excellent solubility, which can greatly improve the use range of the degumming liquid.

[0014] Furthermore, in the water-based degumming liquid for semiconductor manufacturing, the water-soluble organic solvent can be one of diethylene glycol monobutyl ether, triethylene glycol ether monobutyl ether, N-methylpiperazine, and N-ethylpiperazine. The organic solvents have good water solubility and can effectively swell photoresist molecules to promote the removal of photoresist. They can also dissolve small molecular photoresist molecules and increase the service life of the degumming liquid.

[0015] Furthermore, in the water-based degumming liquid for semiconductor manufacturing, the surfactant is a surfactant compounded with a nonionic surfactant lauryl glycoside (APG) and an anionic surfactant sodium α-olefin sulfonate (AOS), wherein the mass ratio of APG to AOS is 2-4:16-18, specifically 4:16, 3:17, 2:18, wherein the ratio of 3:17 has the best effect. Through the synergistic effect of the compounding of nonionic-anionic surfactants, the surface activity of the solution is improved, and the water-soluble stability of the degumming liquid system is also improved, and the removal speed of the photoresist is accelerated, especially the photoresist at the edge and the patterned part can be completely removed, which can significantly improve the yield.

[0016] Furthermore, in the water-based degumming liquid for semiconductor manufacturing, the metal resist is a sugar alcohol compound, specifically adonit. Adonit contains multiple hydroxyl groups, which form hydrogen bonds with hydrogen ions in water, so that a permeable space is generated between the photoresist and the semiconductor substrate after the photoresist is removed, effectively improving the photoresist around the pattern after etching, and its multi-hydroxy structure can prevent the bottom metal film from being corroded by the degumming liquid. It is easy to clean and will not easily remain like benzotriazole-type anti-agents and affect subsequent processes.

[0017] Furthermore, in the above-mentioned water-based deionizing liquid for semiconductor process, the deionized water is electronic grade deionized water, and its resistivity is not less than 18 MΩ at 25°C.

[0018] The remarkable advantages of the present invention are: by adding a special alcohol amine 2-methylamino-3-pyridinemethanol, the heterocyclic structure of which has similar miscibility with the photoresist molecular structure, the photoresist molecules on the wafer can be removed efficiently and quickly at room temperature; by adding a nonionic-anionic surfactant compounded in a specific ratio, a synergistic effect is generated, the surface tension is effectively reduced, the surface activity of the solution is improved, and the water-soluble stability of the degumming liquid system is also improved, the removal speed of the photoresist is accelerated, especially the photoresist on the edge and the patterned part can be completely removed, and the yield can be significantly improved; the water-based organic auxiliary agent can play a solubility-promoting effect, so that the degumming liquid has a good swelling effect on different photoresist molecules, which is beneficial to the stability of the water-based degumming liquid when in use. The sugar alcohol metal anti-corrosion agent can effectively prevent the bottom metal film from being corroded by the degumming liquid. It is easy to clean. The water-based degumming liquid has good water solubility, long service life, and environmentally friendly material composition, and can meet the process requirements of semiconductor manufacturing processes. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. The exemplary implementation modes of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0020] Unless otherwise specified, the experimental methods used in the examples are conventional methods.

[0021] Unless otherwise specified, the materials and reagents used in the examples can be obtained from commercial sources.

[0022] Embodiment and comparative example: A water-based degumming solution used in semiconductor manufacturing process.

[0023] The water-based degumming liquid of the embodiment and the comparative example were prepared according to the composition and mass percentage shown in the following Table 1. The preparation method is as follows: first add deionized water to the stirring kettle at room temperature, add the alcohol amine solvent in sequence at a speed of 30r / min, adjust the speed to 45r / min after the water-soluble organic additive is added, and then add the nonionic and anionic surfactants in proportion in sequence, stir for 30 minutes after adding, finally add the metal resist, stir for 10 minutes after all the additions are completed, and finally filter in sequence with filter elements with a pore size of 2μm and a pore size of 0.5μm to obtain the water-based degumming liquid.

[0024]

[0025] BDG: Diethylene glycol butyl ether BTG: Triethylene glycol butyl ether NMPRZ: N-methylpiperazine

[0026] NEPRZ: N-ethylpiperazine NMP: N-methylpyrrolidone DMSO: dimethyl sulfoxide

[0027] DMAc: dimethylacetamide APG-lauryl glucoside AGP1214 AOS-α-olefin sulfonate sodium

[0028] MOA-4: Fatty alcohol polyoxyethylene ether 6501: Coconut oil fatty acid diethanolamide

[0029] AES: sodium sulfate of fatty alcohol polyoxyethylene ether; S-15: ammonium sulfate of fatty alcohol polyoxyethylene ether

[0030] All of the above materials can be purchased from commercial

[0031] Experimental example: Test of water-based degumming liquid performance

[0032] In order to evaluate the performance of several water-based debonding liquid compositions of Examples 1-7 and Comparative Examples 1-14, the following tests were performed.

[0033] 1. Photoresist removal capability

[0034] Use a 6-inch silicon wafer to deposit 800Å tungsten film and 600Å titanium oxide film, respectively, and spin-coat photoresist to make the film thickness reach 1.0μm. Pre-bake on a hot plate in vacuum for 60s (70℃, 0.05MPa), place the mask on top of the photoresist, and expose it with an exposure machine. Develop with a 2.38% TMAH aqueous solution (21℃, 60s), and hard bake on a hot plate (120℃, 110s). Use gas dry etching to etch the tungsten film and titanium oxide film that are not covered by the photoresist after development to form metal wiring.

[0035] Pour the degumming liquid of each formula into a container, then cut the above sample into chips of 2cm*2cm in size, immerse them in the degumming liquid in the container, soak them at 45℃ for 5min, take them out, rinse them with deionized water, and blow them dry with high-purity nitrogen. Use a scanning electron microscope (SEM) to observe whether there is any photoresist residue on the pattern surface and pattern sidewalls. The evaluation results are as follows:

[0036] ○: The surface and sidewall photoresist are completely removed;

[0037] △: The photoresist on the surface and sidewalls is basically removed, but a small amount of residue can be seen;

[0038] ×: The photoresist on the surface and sidewalls was obviously not removed completely.

[0039] 2. Cu corrosion test.

[0040] Immerse the copper lead frame in the degumming solution of each formula, heat the degumming solution to 60℃, soak for 3 minutes, take it out, rinse it with deionized water, and then blow it dry with high-purity nitrogen. Observe the surface of the sample through a scanning electron microscope. The evaluation results are as follows:

[0041] ○: No corrosion on the lead frame copper surface

[0042] △: The copper surface of the lead frame is slightly corroded

[0043] ×: The copper surface of the lead frame is obviously corroded

[0044] 3. Al corrosion test

[0045] Immerse the aluminum lead frame in the degumming solution of each formula, heat the degumming solution to 60℃, soak for 3 minutes, take it out, rinse it with deionized water, and then blow it dry with high-purity nitrogen. Observe the sample surface through a scanning electron microscope. The evaluation results are as follows:

[0046] ○: No corrosion on the lead frame aluminum surface

[0047] △: The aluminum surface of the lead frame is slightly corroded

[0048] ×: The aluminum surface of the lead frame has obvious corrosion

[0049] 4. Determination of water volatilization

[0050] Water-based degumming liquid will be heated during use, causing the water to evaporate easily. This will reduce the service life of the degumming liquid and require constant refilling. Weigh 50g of degumming liquid into a conical bottle, place it in a water bath at a constant temperature of 50℃, heat it for 1h and 3h, and determine the water volatilization by weighing.

[0051] The evaluation results are as follows:

[0052] ○: 1 hour <1%, 3 hours <2.5%

[0053] △: 1 hour, 1% to 2%; 2.5% < 3 hours < 5%

[0054] ×: 1 hour > 2%; 3 hours > 5%

[0055] 5. Foam determination

[0056] If the degumming liquid is too foamy, it will affect the degumming effect and easily leave residue. Therefore, while ensuring the degumming effect, low foaming performance is more advantageous. The specific foaming power test is as follows:

[0057] 5 mL of degumming liquid of different formulas were placed in the test tubes, and the tubes were shaken vigorously for 15 seconds. The foam height after shaking and after standing for 30 seconds was tested. The lower the foam height, the better. The foam height evaluation results are as follows:

[0058] ○: Foam height is less than 2cm when stopped and less than 1cm after standing

[0059] △: Foam height 2-4cm when stopped, <1.5cm after standing

[0060] ×: Foam height > 5cm when stopped, > 1.5cm after standing

[0061] The test results are shown in Table 2

[0062]

[0063] Analyzing the comparative examples and experimental results of the embodiments in Table 1 and Table 2, it can be seen that within the set range, the degumming liquid has excellent performance in the removal ability of the photoresist, corrosion inhibition, service life and low foaming of the use process. The content of alcohol amine in Comparative Example 1 is too low, so the removal performance of the photoresist is poor. In addition, the pH instability of the system leads to slight corrosion of the Al wiring. At the same time, the volatilization of the water in the system is fast, which will affect the service life; the content of organic solvent in Comparative Example 2 is low, and the poor swelling of the photoresist will affect the removal efficiency of the photoresist; Comparative Examples 3-5 tried other water-soluble solvents, but the degumming effect and the corrosion of the wiring were significantly different; the composite surfactants in Comparative Examples 6-7 did not reach the optimal ratio, so the surface tension of the system was high, which affected the removal effect of the photoresist; Comparative Examples 8-13 tried other non-anionic surfactants, and it can be seen that the actual degumming effect is still quite different from the embodiment. The following surfactants will also affect the corrosion of the wiring, and some surfactants have more foam, which is not suitable for the process requirements; Comparative Example 14 did not add an anticorrosive agent, resulting in more serious corrosion of the metal wiring.

[0064] Appendix: Non-anionic surfactant compounding experiment

[0065] Taking the data of each group ratio of Example 5 as the benchmark, the surface tension of the mixed liquid system with different compounding ratios was measured at 25°C using a TX-500C rotating drop interfacial tension meter, and is listed in Table 3. It can be seen from the experimental data that the compound system has significantly better surface activity than a single surfactant system. The compound system solution has the effect of reducing the surface tension of the system under the synergistic effect, especially when nAGP:nAOS=17:3, it shows the best synergistic effect and synergistic effect, the surface tension of the system is reduced to the greatest extent, and the removal ability of the photoresist is significantly improved. At the same time, other non-anionic surfactant compound systems are also compared, and the compounding effect of AGP and AOS cannot be achieved.

[0066]

[0067] In summary, the positive progress of the present invention is that a water-based degumming solution used in semiconductor processes can efficiently remove photoresist without residue by adding a specific compounded non-anionic surfactant under synergistic and synergistic effects, and at the same time has low corrosion to the metal layer, long service life, low foaming and environmental protection.

[0068] The above embodiments describe the present invention in detail, but they are only examples and do not limit the patent scope of the present invention. Any equivalent modifications and substitutions made to the present invention using the present description are also within the scope of the present invention and are included in the patent protection scope of the present invention.

Claims

1. A water-based degumming solution for semiconductor manufacturing process, characterized in that: In terms of mass percentage, its composition is as follows: Alcoholamine solvent 10%-25%; Water-soluble organic solvent 15%-25%; Surfactant 5%-15%; Metal resist 0.05%-0.5%; Deionized water balance; The sum of the total mass fraction is 100%; The alcohol amine solvent is 2-methylamino-3-pyridinemethanol; The surfactant is formed by compounding lauryl glucoside and sodium α-olefin sulfonate, wherein the mass ratio of lauryl glucoside to sodium α-olefin sulfonate is 17:3; The metal resist is Adonitol; The water-soluble organic solvent is one of diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, N-methylpiperazine and N-ethylpiperazine.

2. The water-based degumming solution for semiconductor manufacturing process according to claim 1, characterized in that: The deionized water is electronic grade deionized water, and its resistivity is not less than 18 MΩ·cm at 25°C.

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