Protective liquid for green light cutting as well as preparation method and application of protective liquid

Abstract

The invention discloses a protection liquid for green light cutting and a preparation method and application thereof.The protection liquid is prepared from, by mass, 20-40 parts of water-soluble resin, 0.25-0.5 part of a green light absorbent and 50-100 parts of a solvent; wherein the water-soluble resin comprises water-soluble polyester and sodium polystyrene sulfonate; the green light absorbent comprises allura red and lac acid. The water-soluble resin is not easy to etch, the etching selection ratio is high, and the etching depth required by the base material can be met under the condition that the loss of the protective film layer is minimum; the relatively high solubility of sodium polystyrenesulfonate is beneficial to improving the solid content of the resin, improving the thickness of a film layer and improving the stability of the protection liquid; besides, the green light absorbent adopts the combination of allura red and lac acid, so that the solution stability and the light stability of the green light absorbent can be ensured, the addition amount of the absorbent is increased, and the absorbance is improved.

Description

Technical Field

[0001] The present application belongs to the field of laser cutting technology, and specifically relates to a protective liquid for green light cutting, and a preparation method and use thereof. Background Art

[0002] Several light sources commonly used in the semiconductor wafer cutting process are red light, purple light, green light, etc. Among them, the wavelength of green light is between red light and purple light, its spot is very small, the focal length is shorter, and it belongs to the cold processing mode, which plays an irreplaceable role in precision cutting processing. Currently, the protective liquid used for cutting is mostly a protective liquid that absorbs purple light wavelengths, and has no obvious absorption of green light wavelengths, resulting in a larger heat-affected area of ​​the wafer after green light cutting, and even affects the chip surface, greatly reducing the wafer cutting yield. Summary of the invention

[0003] Purpose of application: This application provides a protective liquid for green light cutting and its preparation method and use, so as to improve the yield and productivity in the semiconductor manufacturing process.

[0004] Technical solution: The present application provides a protective liquid for green light cutting, which comprises the following components by weight: 20-40 parts of a water-soluble resin, 0.25-0.5 parts of a green light absorber, and 50-100 parts of a solvent;

[0005] Wherein, the water-soluble resin includes water-soluble polyester and sodium polystyrene sulfonate;

[0006] The green light absorbers include allura red and lac acid.

[0007] In some embodiments, the mass ratio of the water-soluble polyester to the sodium polystyrene sulfonate is (2-5):1.

[0008] In some embodiments, the water-soluble polyester has a glass transition temperature of 42-58° C.; and / or

[0009] The number average molecular weight of the water-soluble polyester is 7000-12000; and / or

[0010] The glass transition temperature of the sodium polystyrene sulfonate is 40-50° C.; and / or

[0011] The number average molecular weight of the sodium polystyrene sulfonate is 3000-4000.

[0012] In some embodiments, the water-soluble polyester is selected from at least one of EW100G, EW100Q, EW210, and EW100D.

[0013] In some embodiments, the water-soluble polyester is a water-soluble saturated polyester resin containing a benzene ring and an ester group;

[0014] The water-soluble saturated polyester resin is selected from at least one of Korean SK saturated polyester resins Skybon EW100G, SK EW100Q, SK EW210, and SK EW100D.

[0015] In some embodiments, the mass ratio of the allura red to the lac acid is (1-4):1.

[0016] In some embodiments, the lac acid is selected from at least one of lac acid A, lac acid B, lac acid C, and lac acid E; or

[0017] The green light absorber is used for absorbing light with a wavelength of 500-600nm.

[0018] In some embodiments, the solvent is selected from at least one of deionized water, methanol, ethanol, n-propanol, isopropanol, n-butanol, tert-butanol, isobutanol, ethyl ether, methyl ethyl ether, di-n-butyl ether, propylene glycol methyl ether, ethylene glycol propyl ether, and ethylene glycol butyl ether.

[0019] In some embodiments, the solvent consists of deionized water and ethylene glycol butyl ether; wherein the mass ratio of the deionized water to the ethylene glycol butyl ether is (30-90):(5-40).

[0020] In some embodiments, the present application also provides a method for preparing a protective liquid for green light cutting, comprising the following steps:

[0021] Weigh 20-40 parts of water-soluble resin, 0.25-0.5 parts of green light absorber and 50-100 parts of solvent respectively;

[0022] Mixing a water-soluble resin, a green light absorber and a solvent, stirring at 40-50° C. and a speed of 200-500 rpm for 1-5 hours, to obtain a protective liquid for green light cutting;

[0023] The water-soluble resin includes water-soluble polyester and sodium polystyrene sulfonate; and the green light absorber includes allura red and lac acid.

[0024] In some embodiments, the present application also provides a use of a protective liquid for green light cutting in semiconductor wafer laser cutting and / or plasma cutting processes.

[0025] Beneficial effects: A protective liquid for green light cutting of the present application comprises the following components by mass: 20-40 parts of a water-soluble resin, 0.25-0.5 parts of a green light absorber, and 50-100 parts of a solvent; wherein the water-soluble resin comprises a water-soluble polyester and sodium polystyrene sulfonate; and the green light absorber comprises allura red and lac acid. The water-soluble resin of the present application adopts a combination of water-soluble polyester and sodium polystyrene sulfonate, is not easily etched, has a high etching selectivity, and can meet the etching depth required by the substrate with minimal loss of the protective film layer; the higher solubility of sodium polystyrene sulfonate helps to increase the solid content of the resin, increase the thickness of the film layer, and improve the stability of the protective liquid; in addition, the green light absorber adopts a combination of allura red and lac acid, which can ensure the stability of the solution and the light stability of the green light absorber. At the same time, the amount of absorber added is increased to increase the absorbance.

[0026] It can be understood that the preparation method and use of the protective liquid for green light cutting provided in the embodiments of the present application have all the technical features and beneficial effects of the above-mentioned protective liquid, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The technical solution and other beneficial effects of the present application will be made apparent by describing in detail the specific implementation methods of the present application in conjunction with the accompanying drawings.

[0028] Figure 1 is the UV spectrum of the protective solution provided in Example 1 of the present application;

[0029] Figure 2 is the infrared spectrum of the water-soluble polyester EW210 in Example 1 of the present application;

[0030] Figure 3 This is a picture of a silicon wafer cut using the protective solution of Example 1;

[0031] Figure 4 This is a picture after silicon wafer cutting was performed using the protective liquid of Comparative Example 3. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the embodiments of the present application and the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0033] In the description of the present application, it should be noted that the specific embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, unless otherwise specified, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present application, the term "including" means "including but not limited to". The various embodiments of the present application may be in the form of a range; it should be understood that the description in the form of a range is only for convenience and simplicity, and should not be understood as a rigid limitation on the scope of the present invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single values ​​within the range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which are applicable regardless of the range. In addition, whenever a numerical range is indicated in this article, it is meant to include any quoted numbers (fractions or integers) within the indicated range.

[0034] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application.

[0035] Laser cutting machine is an important tool in the field of cutting and is known as the fastest "knife". Its principle is to irradiate the surface of the material with a high-density and high-energy laser beam, melt, vaporize, ablate or reach the ignition point, and at the same time use the high-speed airflow coaxial with the beam to blow away the molten material, so as to achieve the cutting of the workpiece and form a cut. The three light sources commonly used in semiconductor wafer cutting machines are red light, purple light, and green light. Among them, the wavelength of purple light is 355nm, the wavelength of red light is 1064nm, and the wavelength of green light is 532nm. The wavelength of green light is between red light and purple light. Its spot is very small and the focal length is shorter. It belongs to the cold processing mode and plays an irreplaceable role in precision cutting. The protective liquid currently used for laser cutting is mostly a protective liquid that absorbs 355nm wavelength. There is no obvious absorption of green light (that is, the wavelength is 532nm), resulting in a large heat-affected area of ​​the wafer after green light cutting, and even affects the surface of the chip, greatly reducing the wafer cutting yield. Therefore, the development of laser protective liquid that specifically absorbs green light is imperative. In addition, the application scope of the protective liquid that absorbs green light should not be limited to the laser cutting process. Plasma cutting also requires laser grooving before plasma cutting. This requires that the plasma cutting protective liquid can be coated on the chip surface to form a water-soluble protective mask with a certain thickness, which can simultaneously meet the protection of the Low-K layer on the chip surface during laser grooving and plasma cutting, and effectively protect the chip surface from plasma etching.

[0036] The embodiment of the present application provides a protective liquid for green light cutting, which includes the following components, measured by mass: 20-40 parts of a water-soluble resin, 0.25-0.5 parts of a green light absorber, and 50-100 parts of a solvent; wherein the water-soluble resin includes a water-soluble polyester and sodium polystyrene sulfonate; the green light absorber includes allura red and lac acid.

[0037] It is understandable that the water-soluble resin of the present application adopts a combination of water-soluble polyester and sodium polystyrene sulfonate, which is not easily etched and has a high etching selectivity, and can meet the etching depth required by the substrate with minimal loss of the protective film layer; the higher solubility of sodium polystyrene sulfonate helps to increase the solid content of the resin, increase the thickness of the film layer, and improve the stability of the protective solution; in addition, the green light absorber adopts a combination of allura red and lac acid, which can ensure the stability of the solution and the light stability of the green light absorber. At the same time, the amount of absorber added is increased to improve the absorbance.

[0038] In some embodiments, the embodiments of the present application provide a protective liquid for green light cutting, which includes the following components, in parts by mass: 20-35 parts of a water-soluble resin, 0.25-0.45 parts of a green light absorber, and 60-90 parts of a solvent.

[0039] In some embodiments, the embodiments of the present application provide a protective liquid for green light cutting, which includes the following components, in parts by mass: 20-34 parts of a water-soluble resin, 0.25-0.4 parts of a green light absorber, and 70-85 parts of a solvent.

[0040] In some embodiments, the mass ratio of the water-soluble polyester to the sodium polystyrene sulfonate is (2-5): 1. For example, the mass ratio of the water-soluble polyester to the sodium polystyrene sulfonate can be any one of 2:1, 3:1, 4:1, 5:1 or a range between any two thereof.

[0041] It is understandable that the mass ratio of the water-soluble polyester and sodium polystyrene sulfonate needs to be within the above range. This is because the water-soluble polyester needs to ensure the stability of the film formed by the protective liquid on the one hand, and on the other hand, it also needs to make the film formed by the protective liquid resistant to etching. If the amount of water-soluble polyester is too small, the etching resistance of the protective liquid decreases; if the content of the water-soluble polyester is too much, the film structure is unstable and prone to cracking.

[0042] In some embodiments, the glass transition temperature of the water-soluble polyester is 42-58° C. For example, it can be any one of 42° C., 43° C., 44° C., 45° C., 46° C., 47° C., 48° C., 49° C., 50° C., 51° C., 52° C., 53° C., 54° C., 55° C., 56° C., 57° C., and 58° C., or a range between any two of the values.

[0043] In some embodiments, the glass transition temperature of sodium polystyrene sulfonate is 40-50° C. For example, it can be any one of 40° C., 41° C., 42° C., 43° C., 44° C., 45° C., 46° C., 47° C., 48° C., 49° C., and 50° C., or a range between any two of the values.

[0044] It can be understood that when the glass transition temperature of water-soluble polyester is 42-58°C and the glass transition temperature of sodium polystyrene sulfonate is 40-50°C, the higher glass transition temperature can ensure that the resin has better mechanical properties and thermal stability, the film layer is not easily scratched, and it is not easy to flow into the cutting path due to heat, affecting the plasma or laser cutting process.

[0045] In some embodiments, the number average molecular weight of the water-soluble polyester is 7000-12000, for example, it can be any value of 7000, 8000, 9000, 10000, 11000, 12000, or a range between any two values.

[0046] In some embodiments, the number average molecular weight of sodium polystyrene sulfonate is 3000-4000, for example, it can be any one of 3000, 3100, 3200, 3300, 3400, 3500, 3600, 3700, 3800, 3900, 4000, or a range between any two values.

[0047] It can be understood that when the molecular weight of the water-soluble polyester in this embodiment is 7000-12000 and the molecular weight of sodium polystyrene sulfonate is 3000-4000, the resin has excellent film-forming properties within this molecular weight range and forms a complete protective film on the surface of the substrate, and a high-thickness protective liquid can be prepared at a low viscosity.

[0048] In some embodiments, the water-soluble polyester is selected from at least one of EW100G, EW100Q, EW210, and EW100D.

[0049] It can be understood that the water-soluble polyester is the water-soluble saturated polyester resin of the Skybon EW series provided by SK of South Korea. EW100G, EW100Q, EW210, and EW100D represent the models of this series of resins.

[0050] In some embodiments, the performance parameters of the products EW100G, EW100Q, EW210, and EW100D are shown in Table 1 below.

[0051] Table 1

[0052]

[0053]

[0054] It is understandable that the water-soluble polyester is preferably EW210 because EW210 has a high glass transition temperature and an appropriate number average molecular weight, so EW210 greatly improves the film-forming properties and service life in the protective liquid, and can also improve the stability of EW210 in the protective liquid.

[0055] In some embodiments, the EW series water-soluble polyester structure contains groups such as benzene rings and ester groups, and these groups have relatively high bond energies. The process of plasma etching or laser cutting is chemical etching, which uses plasma to react chemically with the etching material to generate volatile gases. The greater the bond energy of the etching material, the less likely it is to break, that is, the more stable the chemical bond, the less likely it is to be etched. Therefore, the water-soluble polyester of this embodiment has a high etching selectivity, which can meet the etching depth required by the substrate with minimal loss of the protective film layer.

[0056] In some embodiments, sodium polystyrene sulfonate has a high solubility and can cooperate with water-soluble polyester to increase the solid content of the resin, increase the thickness of the film layer, and further improve the stability of the protective solution. In some embodiments, the mass ratio of allura red and lac acid is (1-4): 1. For example, the mass ratio of allura red and lac acid can be any one of 1: 1, 2: 1, 3: 1, 4: 1 or a range between any two values. It can be understood that the green light absorber adopts a combination of allura red and lac acid. The allura red in the green light absorber has poor light stability, but good stability in the solution. The lac acid in the green light absorber has strong light stability, and its stability in the solution is weaker than allura red. The combination of the two can ensure the stability of the solution and the light stability of the absorber, and at the same time increase the amount of absorber added, increase the absorbance, and control the heat affected zone to a minimum.

[0057] In some embodiments, the lac acid is selected from at least one of lac acid A, lac acid B, lac acid C, and lac acid E. The CAS number of lac acid A is 15979-35-8, the CAS number of lac acid B is 17249-00-2, the CAS number of lac acid C is 23241-56-7, and the CAS number of lac acid E is 14597-16-1.

[0058] In some embodiments, Allura Red is a small molecule water-soluble electrolyte with a CAS number of 25956-17-6. When it meets water in the coating, it will produce a charge difference and can also play a role in washing. Therefore, Allura Red can absorb light and improve the cleaning effect of the film layer.

[0059] In some embodiments, the green light absorber is used to absorb light with a wavelength of 500-600 nm.

[0060] In some embodiments, the solvent is selected from any one or any combination of water, alcohol, and ether. Specifically, the solvent is selected from at least one of deionized water, methanol, ethanol, n-propanol, isopropanol, n-butanol, tert-butanol, isobutanol, ethyl ether, methyl ethyl ether, di-n-butyl ether, propylene glycol methyl ether, ethylene glycol propyl ether, and ethylene glycol butyl ether.

[0061] In some embodiments, the solvent is composed of deionized water and ethylene glycol butyl ether; wherein the mass ratio of deionized water to ethylene glycol butyl ether is (30-90):(5-40). For example, the amount of deionized water is 30-90 parts by mass, preferably 40-80 parts by mass, and most preferably 50-75 parts by mass; the amount of ethylene glycol butyl ether is 5-40 parts by mass, preferably 5-30 parts by mass, and most preferably 5-20 parts by mass.

[0062] It is understandable that ethylene glycol butyl ether can be used as both a solvent and a film plasticizer, because ethylene glycol butyl ether is an organic solvent, has good compatibility with the resin and will not remain in the film for a long time to affect the film etching selectivity.

[0063] In some embodiments, the water-soluble polyester, sodium polystyrene sulfonate and allura red used in the protective solution of this embodiment are all sulfonate systems, which have excellent compatibility and are conducive to forming a uniform and stable film layer.

[0064] In some embodiments, this embodiment further provides a method for preparing a protective liquid for green light cutting, comprising the following steps:

[0065] Weigh 20-40 parts of water-soluble resin, 0.25-0.5 parts of green light absorber and 50-100 parts of solvent respectively;

[0066] Mixing a water-soluble resin, a green light absorber and a solvent, stirring at 40-50° C. at a speed of 200-500 rpm for 1-5 hours, to obtain a protective liquid for green light cutting;

[0067] The water-soluble resin includes water-soluble polyester and sodium polystyrene sulfonate; the green light absorber includes allura red and lac acid.

[0068] In some embodiments, the stirring speed may be any one of 200 rpm, 300 rpm, 400 rpm, 500 rpm, or a range between any two values.

[0069] In some embodiments, the stirring time can be any one of 1 h, 2 h, 3 h, 4 h, 5 h, or a range between any two values.

[0070] In some embodiments, the present application also provides a method for using a protective liquid for green light cutting, as follows: first clean the wafers of different sizes to be coated; set the spin coating program, add cutting protection material on the wafer, the amount is 10ml / 4 inches, 15ml / 6 inches, 25ml / 8 inches, 35ml / 12 inches, and spin coat at 1000rpm for 2 minutes; after spin coating, proceed to the next cutting process.

[0071] In some embodiments, the present embodiment also provides the use of a protective liquid for green light cutting in a semiconductor wafer laser cutting and / or plasma cutting process. The protective liquid for green light cutting of the present application can be applied to the cutting protection of wafers. It can adapt to various wafer structures and form a protective film on the surface of the wafer to ensure that the wafer is not scratched by debris during the cutting process, so as to improve the yield of semiconductor products and the efficiency of cutting.

[0072] It should be noted that all raw materials in the examples of the present application can be obtained commercially. Among them, the molecular weight of the water-soluble resin satisfies the interval range, that is, the specific molecular weight of the water-soluble resin, does not mean its exact molecular weight, but a suitable fluctuation range (for example, the molecular weight can be measured by various viscosity methods).

[0073] Examples 1-7

[0074] A protective liquid for green light cutting is provided. The specific substances and the proportions of the components used in Examples 1-7 are shown in Table 2.

[0075] Comparative Example 1

[0076] A protective liquid for green light cutting is provided. Among the specific components, polyvinyl alcohol is used as the water-soluble resin, and no water-soluble polyester is used. See Table 2 for details.

[0077] Comparative Example 2

[0078] A protective liquid for green light cutting is provided. Among the specific components, the water-soluble resin uses water-soluble polyester, but sodium polystyrene sulfonate is not used. See Table 2 for details.

[0079] Comparative Example 3

[0080] Provided is a protective liquid for green light cutting. In the specific components, the green light absorber does not use allura red, but only uses lac acid, as shown in Table 2.

[0081] Comparative Example 4

[0082] Provided is a protective liquid for green light cutting. In the specific components, the green light absorber does not use lac acid, but only uses allura red, as shown in Table 2.

[0083] Table 2

[0084]

[0085]

[0086] The protective liquid was prepared according to the specific components and parts in Table 2, specifically: the water-soluble resin, green light absorber and solvent were weighed in respective mass parts; each component was added into a mixing container equipped with a stirrer, and stirred at 45°C at a speed of 300 rpm for 3 hours to obtain a protective liquid for green light cutting.

[0087] The protective solution obtained in Example 1 was subjected to an absorbance test, and the obtained UV spectrum is shown in FIG. Figure 1 It can be seen that there are obvious absorption peaks in the spectrum within the range of 500-550nm, including the absorption peak at 532nm, which shows that the protective solution prepared in Example 1 can absorb green light with a wavelength of 532nm.

[0088] The water-soluble polyester EW210 in Example 1 was subjected to infrared testing, and the infrared spectrum obtained was shown in Figure 2 , it can be seen from the figure that at 1720cm -1 The characteristic peak of ester group is 1450cm -1 The peak at 4 is the characteristic peak of C=C bond of benzene ring, which proves that there are ester groups and benzene rings in water-soluble polyester.

[0089] See also Figure 3 and Figure 4 , are pictures of silicon wafer cutting using the protective liquids of Example 1 and Comparative Example 3, respectively. Figure 3 It can be seen that after the silicon wafer is cut, the heat-affected zone near the cutting path is small, about 3.45μm; Figure 4 It can be seen in the figure that after the silicon wafer is cut, the heat-affected zone near the cutting path is large, about 10.35 μm. Therefore, the use of the protective liquid provided in this embodiment can reduce the heat-affected zone of the silicon wafer and greatly improve the cutting yield of the wafer.

[0090] The protective solutions of Examples 1-7 and Comparative Examples 1-4 were further used to perform silicon wafer cutting, and the heat affected zone size and etching selectivity data obtained were shown in Table 3.

[0091] Among them, the size of the heat-affected zone is obtained by measuring under a microscope after laser cutting (3.5W); the etching selectivity refers to the ratio of the etching rate of the film layer to the substrate (wafer) after plasma cutting, which is obtained by SEM slicing measurement. The etching selectivity is defined as the ratio of the etching rate of the etched material to the etching rate of another material.

[0092] Table 3

[0093]

[0094]

[0095] It can be seen from Table 3 that the thermal impact of the above embodiments 1-7 is within 5 microns, and the etching selectivity is above 1: 150. Within this range, the thermal impact will not affect the chip and reduce the chip yield, and the etching selectivity is relatively high, so there is no risk of missing etching, thereby damaging the chip and reducing the yield.

[0096] In comparative example 1, polyvinyl alcohol is used as the water-soluble resin, which results in a significantly reduced etching selectivity and a larger heat-affected zone. In comparative example 2, sodium polystyrene sulfonate is not added, the resin content is insufficient, and the film layer is thin, resulting in the film layer being etched through during etching and etching to the substrate, causing leakage.

[0097] The test results show that when the amount of mixed green light absorbers exceeds 0.5 parts, or the amount of a single green light absorber exceeds 0.25 parts, the protective liquid will easily become turbid and form a turbid liquid, which cannot form a uniform and stable film layer and cannot be used as a protective liquid to be coated on the wafer surface. Comparative Example 3 uses only lac acid A as a green light absorber, which leads to a significant increase in the size of the heat-affected zone and a decrease in the etching selectivity; Comparative Example 4 uses only allura red as a green light absorber, which leads to a significant increase in the size of the heat-affected zone and a decrease in the etching selectivity.

[0098] In summary, the use of water-soluble polyester, especially the combination of Skybon EW series water-soluble saturated polyester resin and sodium polystyrene sulfonate provided by SK of South Korea, as a water-soluble resin is not easily etched and has a high etching selectivity; and adding a combination of allura red and lac acid as a green light absorber can not only reduce the size of the heat-affected zone, but also increase the etching selectivity, thereby improving the yield and productivity in the semiconductor manufacturing process.

[0099] The above is a detailed introduction to a protective liquid for green light cutting, a preparation method and a use thereof of the present application. Specific examples are used in the present application to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solution and core idea of ​​the present application. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the present application.

Claims

1. A protective liquid for green light cutting, characterized in that: The composition comprises the following components by weight: 20-40 parts of a water-soluble resin, 0.25-0.5 parts of a green light absorber, and 50-100 parts of a solvent; Wherein, the water-soluble resin includes water-soluble polyester and sodium polystyrene sulfonate; The green light absorbers include allura red and lac acid.

2. The protective liquid for green light cutting according to claim 1, characterized in that: The mass ratio of the water-soluble polyester to the sodium polystyrene sulfonate is (2-5):

1.

3. The protective liquid for green light cutting according to claim 1, characterized in that: The glass transition temperature of the water-soluble polyester is 42-58° C.; and / or The number average molecular weight of the water-soluble polyester is 7000-12000; and / or The glass transition temperature of the sodium polystyrene sulfonate is 40-50° C.; and / or The number average molecular weight of the sodium polystyrene sulfonate is 3000-4000.

4. The protective liquid for green light cutting according to claim 3, characterized in that: The water-soluble polyester is selected from at least one of EW100G, EW100Q, EW210 and EW100D.

5. The protective liquid for green light cutting according to claim 1, characterized in that: The mass ratio of the allura red to the lac acid is (1-4):

1.

6. The protective liquid for green light cutting according to claim 5, characterized in that: The lac acid is selected from at least one of lac acid A, lac acid B, lac acid C and lac acid E; or The green light absorber is used for absorbing light with a wavelength of 500-600nm.

7. The protective liquid for green light cutting according to claim 1, characterized in that: The solvent is selected from at least one of deionized water, methanol, ethanol, n-propanol, isopropanol, n-butanol, tert-butanol, isobutanol, ethyl ether, methyl ethyl ether, di-n-butyl ether, propylene glycol methyl ether, ethylene glycol propyl ether and ethylene glycol butyl ether.

8. The protective liquid for green light cutting according to claim 7, characterized in that: The solvent consists of deionized water and ethylene glycol butyl ether; wherein the mass ratio of the deionized water to the ethylene glycol butyl ether is (30-90):(5-40).

9. A method for preparing a protective liquid for green light cutting, characterized in that: The following steps are involved: Weigh 20-40 parts of water-soluble resin, 0.25-0.5 parts of green light absorber and 50-100 parts of solvent respectively; Mixing a water-soluble resin, a green light absorber and a solvent, stirring at 40-50° C. and a speed of 200-500 rpm for 1-5 hours, to obtain a protective liquid for green light cutting; The water-soluble resin includes water-soluble polyester and sodium polystyrene sulfonate; and the green light absorber includes allura red and lac acid.

10. Use of the protective liquid for green light cutting according to any one of claims 1 to 8 in semiconductor wafer laser cutting and / or plasma cutting processes.

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