Photoresist stripping liquid with function of protecting various metals and application of photoresist stripping liquid

Abstract

The invention belongs to the technical field of microelectronics, and discloses a photoresist stripping liquid with a function of protecting various metals and application of the photoresist stripping liquid. The photoresist stripping liquid comprises the following preparation raw materials in percentage by mass: 1-30% of organic alcohol amine; 0.1-5% of a sulfhydryl compound; 0.1 to 5% of a surfactant; and the balance of organic solvent. Aiming at the technical bottlenecks that a photoresist stripping solution with a strong photoresist removing effect can corrode a metal wiring or a substrate material and a stripping solution friendly to the metal and the substrate material is not thorough in stripping in the prior art, the invention provides a photoresist stripping solution with a function of protecting various metals, and aims at researching the technical bottlenecks that the photoresist stripping solution with a strong photoresist removing effect can corrode the metal wiring or the substrate material in the photoresist stripping process. According to the photoresist stripping liquid, photoresist residues on a wafer are effectively and efficiently removed, meanwhile, the sulfydryl compound and the surfactant are added, so that the surface performance of an organic compound is improved, metal aluminum, silver, nickel and titanium are protected, and particularly corrosion to metal silver and aluminum can be greatly improved.

Description

Technical Field

[0001] The invention relates to the field of microelectronic technology, in particular to a photoresist stripping solution with multiple metal protection functions and its application. Background Art

[0002] In the manufacturing process of LED and semiconductor devices, photoresist is usually needed as a resist mask for pattern transfer, and then the pattern transfer is completed through photolithography processes such as exposure, development, and etching. After obtaining the required pattern, the photoresist residue needs to be removed before the next process. This process requires the complete removal of unnecessary photoresist and no corrosion of any substrate, especially the strict control of corrosion of various metal materials.

[0003] At present, in the manufacturing process of power semiconductor devices and some LED chips, in order to obtain lower on-resistance, the technical means of back metal processing are usually adopted. IGBT (insulated gate bipolar transistor) is a widely used power semiconductor device, and its back metal generally uses an aluminum-titanium-nickel-silver structure. The outermost silver is used as a conductive material, which plays the role of electrical conduction, thermal conduction, welding substrate and oxidation prevention; nickel is used as a barrier layer to prevent silver from diffusing into the device and prevent the metal layer from being punched through during packaging and wire bonding; titanium mainly plays the role of ohmic contact to reduce contact resistance; aluminum, as a relatively special metal in IGBT, can form aluminum nails with silicon to further reduce contact resistance. At the same time, aluminum is also used as an acceptor impurity to further increase the surface P-type concentration and reduce the saturation voltage. Therefore, most photoresist stripping solutions used on IGBT devices require that while completely removing the photoresist residue, the metal silver / nickel / titanium / aluminum on the back of the wafer cannot be corroded or discolored.

[0004] When photoresist stripping liquid is actually used, LED chips or semiconductor wafers are mostly soaked or rinsed, and heating, ultrasound, vibration and other means are also used to assist. There are many examples of alkanolamine or hydroxylamine mixed with different solvent additives in the current common stripping liquid composition. For example, CN 108803263 A discloses an alkaline photoresist stripping liquid, which is composed of organic alcohol amine, polar organic solvent, corrosion inhibitor and surfactant. Since this type of photoresist stripping liquid does not contain water, it will improve the corrosion of the substrate during the degumming process, but due to the short degumming time, it is difficult to judge whether the metal corrosion will be caused as the service life of the stripping liquid increases, and the patent does not mention the protection of the metal Al on the back of the IGBT. US5529887 discloses an alkaline stripping liquid composed of potassium hydroxide (KOH), alkyl glycol monoalkyl ether, water-soluble fluoride and water. The wafer is immersed in the stripping liquid, and the photoresist on the metal and dielectric substrate can be removed at 40-90°C, but it has a high corrosion to the semiconductor wafer substrate, and the fluorine content is not environmentally friendly. Although there are many systems for the composition of photoresist stripping solutions, there are still problems such as photoresist stripping solutions with strong debonding effects will corrode metal wiring or substrate materials, and stripping solutions that are friendly to metals and substrate materials will not strip thoroughly. In addition, in order to ensure efficient stripping effects, highly corrosive substances (such as HF) are used, which leads to a large amount of "three wastes", high treatment costs, and environmental pollution.

[0005] Therefore, providing an economical photoresist stripping solution composition with strong degumming effect and no corrosion to the base metal is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0006] The purpose of the present invention is to provide a photoresist stripping solution with multiple metal protection functions and its application, so as to solve the problems of poor photoresist stripping effect and corrosion of base metal in the prior art photoresist stripping solution.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] The present invention provides a photoresist stripping solution with multiple metal protection functions, comprising the following preparation raw materials in percentage by mass:

[0009] Organic alcohol amine 1-30%;

[0010] Thiol compounds 0.1-5%;

[0011] Surfactant 0.1~5%;

[0012] Residue of organic solvent.

[0013] Preferably, in the above-mentioned photoresist stripping solution with multiple metal protection functions, the organic alcohol amine includes one or more of alkanolamine, triethanolamine, diisopropanolamine, diglycolamine, ethanolamine, N-methylethanolamine, N-ethylethanolamine, N-propylethanolamine, N-butylethanolamine, diethanolamine, 1-amino-2-propanol, and N-methylisopropanolamine.

[0014] Preferably, in the above-mentioned photoresist stripping solution with multiple metal protection functions, the thiol compound includes one or more of cysteine, cystine, mercaptoethanol, 2-mercaptobenzothiazole, 1-phenyl-5-mercaptotetrazole, methyl mercaptan, ethyl mercaptan, ethanedithiol, 1-propanethiol, 1,3-propanedithiol, catolipol, coenzyme A, and glutathione.

[0015] Preferably, in the above-mentioned photoresist stripping solution with multiple metal protection functions, the surfactant is one or more of polyethylene glycol 400, polyethylene glycol 600, polyethylene glycol 800, tetratol ester, sorbitol ester, ethylene glycol ester, monoglycerol ester, and polyglycerol ester.

[0016] Preferably, in the above-mentioned photoresist stripping solution having multiple metal protection functions, the organic solvent is one or more water-soluble or water-miscible organic solvents.

[0017] The invention also provides an application of a photoresist stripping solution having multiple metal protection functions.

[0018] Preferably, in the application of the above-mentioned photoresist stripping solution having multiple metal protection functions, the application method comprises the following steps:

[0019] Immerse the wafer containing photoresist residues in photoresist stripping liquid, soak it for a period of time at a certain temperature, and then take it out.

[0020] Preferably, in the application of the above-mentioned photoresist stripping solution with multiple metal protection functions, the immersion temperature is 25 to 80° C., and the immersion time is 3 to 15 minutes.

[0021] It can be seen from the above technical solution that compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention studies the technical bottlenecks faced by photoresist stripping in the prior art, that is, photoresist stripping solutions with strong degumming effects can corrode metal wiring or substrate materials, and stripping solutions that are friendly to metals and substrate materials cannot strip thoroughly, and provides a photoresist stripping solution with multiple metal protection effects, wherein the organic alcohol amine is alkaline and decomposes the photoresist into small molecular compounds; the organic solvent further dissolves the decomposed molecules, and the mercapto compound and the surfactant are corrosion inhibitors to prevent the stripping solution from corroding the base metal. While the photoresist stripping solution effectively and efficiently removes the photoresist residues on the wafer, the surface properties of the organic compound are improved by adding the mercapto compound and the surfactant, thereby protecting metal aluminum, silver, nickel, and titanium, and especially greatly improving the corrosion of metal silver and aluminum. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments or the prior art are briefly introduced below.

[0024] Figure 1 This is an electron microscope image of the silver test piece after being immersed in the photoresist stripping solution in Example 7 for 7 days;

[0025] Figure 2 This is an electron microscope image of the silver test piece after being immersed in the photoresist stripping solution in Comparative Example 1 for 7 days;

[0026] Figure 3 This is an electron microscope image of the aluminum test piece after being immersed in the photoresist stripping solution in Example 7 for 7 days;

[0027] Figure 4 This is an electron microscope image of the aluminum test piece after being immersed in the photoresist stripping solution in Comparative Example 1 for 7 days;

[0028] Figure 5 This is an electron microscope image of a nickel test piece after being immersed in the photoresist stripping solution in Example 7 for 7 days;

[0029] Figure 6 This is an electron microscope image of a nickel test piece after being immersed in the photoresist stripping solution in Comparative Example 1 for 7 days;

[0030] Figure 7 This is an electron microscope image of a titanium test piece after being immersed in the photoresist stripping solution in Example 7 for 7 days;

[0031] Figure 8 This is an electron microscope image of the titanium test piece after being immersed in the photoresist stripping solution in Comparative Example 1 for 7 days. DETAILED DESCRIPTION

[0032] The present invention provides a photoresist stripping solution with multiple metal protection functions, comprising the following preparation raw materials in percentage by mass:

[0033] Organic alcohol amine 1-30%;

[0034] Thiol compounds 0.1-5%;

[0035] Surfactant 0.1~5%;

[0036] Residue of organic solvent.

[0037] In the present invention, the mass percentage of the organic alcohol amine is preferably 1 to 30%, more preferably 10 to 25%, and even more preferably 15 to 20%.

[0038] In the present invention, the mass percentage of the mercapto compound is preferably 0.1 to 5%, more preferably 0.5 to 3.5%, and even more preferably 1 to 2.5%.

[0039] In the present invention, the mass percentage of the surfactant is preferably 0.1 to 5%, more preferably 0.5 to 3.5%, and even more preferably 1 to 2.5%.

[0040] In the present invention, the organic alcohol amine preferably includes one or more of alkanolamine, triethanolamine, diisopropanolamine, diglycolamine, ethanolamine, N-methylethanolamine, N-ethylethanolamine, N-propylethanolamine, N-butylethanolamine, diethanolamine, 1-amino-2-propanol, and N-methylisopropanolamine.

[0041] In the present invention, the thiol compound preferably includes one or more of cysteine, cystine, mercaptoethanol, 2-mercaptobenzothiazole, 1-phenyl-5-mercaptotetrazole, methyl mercaptan, ethyl mercaptan, ethanedithiol, 1-propanethiol, 1,3-propanedithiol, catolipol, coenzyme A, and glutathione.

[0042] In the present invention, the surfactant is preferably one or more of polyethylene glycol 400, polyethylene glycol 600, polyethylene glycol 800, tetratol ester, sorbitol ester, ethylene glycol ester, glycerol monoester, and polyglycerol ester.

[0043] In the present invention, the organic solvent is preferably one or more water-soluble or water-miscible organic solvents, and is further preferably sulfolane, methyl sulfoxide, N-cyclohexyl pyrrolidone, N-methyl pyrrolidone, ethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, tripropylene glycol methyl ether, tripropylene glycol monobutyl ether, propylene glycol propyl ether, diethylene glycol n-butyl ether, dimethylacetamide, 2-imidazolidinone, hexyloxypropylamine, poly(oxyethylene)diamine, and dimethyl sulfoxide.

[0044] In the present invention, the water-soluble or water-miscible organic solvent includes a solvent that can be mixed with water and each other to form a homogeneous solution at standard temperature and pressure.

[0045] In the present invention, the photoresist stripping solution is alkaline, usually greater than 8, or greater than 9, or 9-12, or 10-12.

[0046] In the present invention, a method for preparing a photoresist stripping solution having multiple metal protection functions is to physically mix the raw materials.

[0047] The invention also provides an application of a photoresist stripping solution having multiple metal protection functions.

[0048] In the present invention, the application method comprises the following steps:

[0049] Immerse the wafer containing photoresist residues in photoresist stripping liquid, soak it for a period of time at a certain temperature, and then take it out.

[0050] In the present invention, the soaking temperature is preferably 25 to 80°C, more preferably 30 to 60°C, and more preferably 35 to 55°C; the soaking time is preferably 3 to 15 min, more preferably 7 to 12 min, and more preferably 9 to 10 min.

[0051] In the present invention, after the soaking is completed and the sample is taken out, the process further comprises: rinsing with water and then drying with nitrogen.

[0052] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] Example

[0054] The photoresist stripping solution with multiple metal protection functions can be prepared by mixing the raw materials in Table 1.

[0055] Comparative Example

[0056] Photoresist stripping solution can be prepared by mixing the raw materials in Table 1.

[0057] Table 1 Components and contents of photoresist stripping solutions in Examples and Comparative Examples

[0058]

[0059] Application Example 1: Stripping of Photoresist

[0060] The wafer covered with photoresist was immersed in a constant temperature oscillator at 80°C and oscillated at a vibration frequency of about 60 r / min for 5 minutes, then rinsed with water and dried with nitrogen, and the time for the photoresist to be completely stripped was measured and evaluated according to the following evaluation criteria. The results are shown in Table 2.

[0061] (Evaluation Criteria)

[0062] ○: The stripping speed is the same as or faster than that of the existing stripping solution;

[0063] △: The stripping speed is slightly slower than the existing stripping solution;

[0064] ×: The stripping speed is much slower than that of existing stripping liquids.

[0065] Application Example 2 Comparison of Etching Rates of Ag / Al / Ni / Ti

[0066] Since the degumming time was short under the conditions of Experiment 1, there was no corrosion on the metal surface. Therefore, after removing the photoresist, the corrosion rate of the photoresist stripping solution on the metal was further evaluated. The test temperature was room temperature and the test time was 7 days. The wafers plated with a 1kA metal layer were cut into 2cm×2cm square test pieces. The resistance value of the test pieces was tested by a four-probe metal resistance tester and the corresponding thickness was calculated. The thickness value of each test piece before and after immersion was tested to obtain the etching rate per unit time. The results are shown in Table 2.

[0067] Table 2 Test results of application examples 1 and 2

[0068] Example Peelability Silver etching rate A / day Aluminum etching rate A / day Nickel etching rate A / day Titanium etching rate A / day 1 X 58 101 74 69 2 ○ 27 10 8 13 3 △ 88 15 12 13 4 ○ 42 45 64 7 5 ○ 20 2 2 0 6 ○ 56 12 10 15 7 ○ 10 3 1 0 8 ○ 33 18 43 12 9 ○ 109 32 58 26 10 ○ 36 12 14 7 Comparative Example 1 △ 240 130 133 128 Comparative Example 2 X Unable to detect 140 127 78

[0069] It is impossible to measure whether the corrosion thickness of the metal layer exceeds 1kA of the coating and the corrosion is serious.

[0070] The results in Table 2 confirm that the stripping liquid system containing both organic alcohol amine and solvent has good stripping performance for photoresist. In Comparative Example 1, there is no surfactant, and the metal aluminum and nickel are severely corroded. In Comparative Example 2, no mercapto compound is added, and the metal silver is severely corroded. The amount of organic alcohol amine added is insufficient, and the stripping performance is poor.

[0071] Figure 1 , 3 , 5, and 7 are electron microscope images of silver, aluminum, nickel, and titanium test pieces after being immersed in the photoresist stripping solution in Example 7 for 7 days. Figure 1 , 3 , 5, and 7 show that the silver, aluminum, nickel, and titanium test pieces have no signs of corrosion and have good surfaces.

[0072] Figure 2 , 4, 6, and 8 are electron microscope images of silver, aluminum, nickel, and titanium test pieces after being immersed in the photoresist stripping solution in Comparative Example 1 for 7 days. Figure 2 , 4 , 6, and 8 show that the surfaces of the silver, aluminum, nickel, and titanium test pieces are severely corroded.

[0073] In summary, the present invention provides such a photoresist stripping solution composition, which has excellent stripping performance and good protection performance for metal silver, aluminum, nickel, titanium, etc. under the photoresist. Since the components of the photoresist stripping solution composition are all low in volatility and toxicity, it is environmentally friendly and has excellent operability.

[0074] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A photoresist stripping solution having a plurality of metal protection functions, characterized in that: The preparation raw materials contain the following mass percentages: Organic alcohol amine 1-30%; Thiol compounds 0.1-5%; Surfactant 0.1~5%; Residue of organic solvent.

2. The photoresist stripping solution with multiple metal protection functions according to claim 1, characterized in that: The organic alcohol amine includes one or more of alkanolamine, triethanolamine, diisopropanolamine, diglycolamine, ethanolamine, N-methylethanolamine, N-ethylethanolamine, N-propylethanolamine, N-butylethanolamine, diethanolamine, 1-amino-2-propanol, and N-methylisopropanolamine.

3. The photoresist stripping solution with multiple metal protection functions according to claim 2, characterized in that: The thiol compound includes one or more of cysteine, cystine, mercaptoethanol, 2-mercaptobenzothiazole, 1-phenyl-5-mercaptotetrazole, methyl mercaptan, ethyl mercaptan, ethanedithiol, 1-propanethiol, 1,3-propanedithiol, catolipol, coenzyme A, and glutathione.

4. The photoresist stripping solution with multiple metal protection functions according to claim 3, characterized in that: The surfactant is one or more of polyethylene glycol 400, polyethylene glycol 600, polyethylene glycol 800, tetratol ester, sorbitol ester, ethylene glycol ester, glycerol monoester and polyglycerol ester.

5. The photoresist stripping solution with multiple metal protection functions according to claim 4, characterized in that: The organic solvent is one or more water-soluble or water-miscible organic solvents.

6. Use of the photoresist stripping solution having multiple metal protection functions as claimed in any one of claims 1 to 5.

7. The use of the photoresist stripping solution with multiple metal protection functions according to claim 6, characterized in that: The application method comprises the following steps: Immerse the wafer containing photoresist residues in photoresist stripping liquid, soak it for a period of time at a certain temperature, and then take it out.

8. The use of the photoresist stripping solution with multiple metal protection functions according to claim 7, characterized in that: The soaking temperature is 25-80° C., and the soaking time is 3-15 minutes.

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