A high-power laser cutting resistant protective material and a preparation method thereof

Abstract

The application provides a high-power laser cutting resistant protective material and a preparation method thereof, the protective material comprises the following components in percentage by weight: heat-resistant water-soluble resin 15-40%; water-soluble UV absorber 1-5%; auxiliary agent 1-5%; solvent 50-83%; the heat-resistant water-soluble resin comprises water-soluble PET and / or sodium polystyrene sulfonate; the auxiliary agent comprises a leveling agent, and the leveling agent comprises a fluorocarbon surfactant and a polysiloxane oligomer. The protective material provided by the application can reduce overheating burning during laser cutting, reduce the adhesion of fragment particles to wafers, solve the carbonization residue problem in the cutting path during high-power laser cutting, and has the characteristics of being easy to clean with pure water and good leveling performance.

Description

Technical Field

[0001] This invention belongs to the field of laser cutting technology and relates to a protective material resistant to high-power laser cutting and its preparation method. Background Technology

[0002] With the rapid development of the chip industry, chip thickness is becoming increasingly thinner to improve heat dissipation efficiency, reduce chip packaging size, lower internal stress, and enhance electrical performance. The thickness of the wafers, the source of these chips, is also decreasing. However, as wafers become thinner, the difficulty of cutting them also increases. Semiconductor wafer materials are mainly GaAs, InP, GaN, and SiC. These materials are brittle, and the mechanical stress generated by the cutting wheel easily leads to edge chipping and breakage. This is especially true for third-generation semiconductors, such as silicon carbide, whose Mohs hardness is almost the same as diamond. Using a cutting wheel results in rapid wheel wear, frequent replacements, increased costs, and low efficiency. Furthermore, with the reduction in wafer thickness and the increase in cutting precision, edge chipping and breakage during the cutting wheel process are becoming increasingly serious, far from meeting the yield and production line requirements. Therefore, laser cutting has become the primary choice.

[0003] Laser ablation cutting is a non-contact processing method that utilizes the physical phenomena generated by the interaction between laser and material, including thermal and mechanical effects. As laser power density increases, the material undergoes heating, melting, and vaporization processes. This process does not exert mechanical stress on the wafer, resulting in minimal damage. Because fragments and slag are generated during the cutting process, a cutting protective material is applied beforehand. This material effectively reduces overheating during laser cutting and prevents particles generated during the cutting process from adhering to the wafer, thus avoiding damage and contamination of the heat-affected zone. As wafers become increasingly thinner, brittle materials with low Mohs hardness, such as GaAs and InP, exhibit even lower fracture strength after thinning, making them highly susceptible to breakage and wafer scrap. Therefore, for very thin wafers (thickness <200μm), full laser cutting is the primary choice. Full cutting requires significantly higher power than surface cutting, and the increased cutting power places higher demands on the heat resistance of the protective material.

[0004] Currently available laser cutting protective materials have poor heat resistance (weight loss temperature within 5% is less than 300℃) and thin film thickness. During high-power laser cutting, the material degenerates and loses its protective effect. After laser ablation cutting, it can lead to severe carbonization residue near the cutting track after cleaning, contaminating the chip and even causing chip damage.

[0005] Therefore, in this field, there is a desire to develop a protective material that can withstand high-power laser cutting. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a protective material resistant to high-power laser cutting and its preparation method. The protective material provided by this invention can reduce overheating and burning during laser cutting, reduce the adhesion of fragments to the wafer, solve the problem of carbonization residue on the cutting path during high-power laser cutting, and is easily cleanable with pure water.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a protective material resistant to high-power laser cutting, the protective material comprising, by weight percentage, the following components:

[0009]

[0010] The heat-resistant water-soluble resin includes water-soluble PET and / or sodium polystyrene sulfonate;

[0011] The additives include leveling agents, which include fluorocarbon surfactants and polysiloxane oligomers.

[0012] The protective material provided by this invention comprises a combination of heat-resistant water-soluble resin, water-soluble UV absorber, additives, and solvents. Through the screening and synergistic compounding of specific components, especially the selection of heat-resistant water-soluble resin and additives, and further, the content and molecular weight of heat-resistant water-soluble resin are limited, so that the protective material has a high film thickness to provide heat insulation and adsorption, solves the problem of carbonization residue near the cutting path after high-power laser cutting, and has good leveling performance.

[0013] In this invention, the heat-resistant water-soluble resin has a rigid benzene ring structure, which has excellent temperature resistance and can prevent the material from degenerating and losing its washability at high temperatures. Furthermore, the content of the heat-resistant water-soluble resin in the formulation is greater than 10%, ensuring a certain film thickness after film formation to achieve the effect of heat insulation and debris adsorption.

[0014] In this invention, the leveling agent comprises a combination of fluorocarbon surfactant and polysiloxane oligomer. The fluorocarbon surfactant can reduce static surface tension and quickly wet the substrate, while the polysiloxane oligomer can reduce dynamic surface tension during high-speed rotation, ensuring a smooth and defect-free film surface. The combination of the two can achieve good leveling performance.

[0015] In this invention, the protective material resistant to high-power laser cutting refers to a laser cutting process with a power of ≥4W, such as 4W, 5W, 6W, 7W, 8W, 9W, 10W, 12W, 15W, 20W, etc.

[0016] In this invention, the amount of heat-resistant water-soluble resin used in the protective material, by weight percentage, can be 15%, 18%, 20%, 23%, 25%, 28%, 30%, 33%, 35%, 38%, 40%, etc.

[0017] In this invention, the amount of water-soluble UV absorber used in the protective material can be 1%, 2%, 3%, 4%, 5%, etc., by weight percentage.

[0018] In this invention, the protective material may contain additives at a weight percentage of 1%, 2%, 3%, 4%, 5%, etc.

[0019] In this invention, the amount of solvent used in the protective material can be 50%, 55%, 60%, 65%, 70%, 75%, 80%, 83%, etc., by weight percentage.

[0020] Preferably, the heat-resistant water-soluble resin further includes any one or a combination of at least two of polyether ester, polyvinylpyrrolidone, and polyethylene glycol.

[0021] Preferably, the heat-resistant water-soluble resin is a combination of water-soluble PET and sodium polystyrene sulfonate, or a combination of water-soluble PET and polyvinylpyrrolidone, or a combination of sodium polystyrene sulfonate and polyvinylpyrrolidone.

[0022] Preferably, the weight-average molecular weight of the heat-resistant water-soluble resin is 9,000-50,000, such as 9,000, 10,000, 12,000, 15,000, 18,000, 20,000, 25,000, 30,000, 35,000, 40,000, 45,000, 50,000, etc.

[0023] Preferably, the weight-average molecular weight of the water-soluble PET and the sodium polystyrene sulfonate is independently 9,000-15,000, for example, 9,000, 10,000, 11,000, 12,000, 13,000, 14,000, 15,000, etc. Lower molecular weight substances provide higher film thicknesses when the viscosity of the adhesive (i.e., the protective material) is lower.

[0024] Preferably, the weight-average molecular weight of the polyvinylpyrrolidone is 20,000-50,000, such as 20,000, 25,000, 30,000, 35,000, 40,000, 45,000, 50,000, etc.

[0025] Preferably, the water-soluble UV absorber comprises any one or a combination of at least two of benzotriazoles, hydroxyphenyltriazines, and stilbene sulfonates. The UV absorber of the present invention has a relatively rigid structure, which gives it excellent temperature resistance.

[0026] The protective material for high-power laser cutting provided by this invention combines a water-soluble PET resin with a rigid structure with a UV absorber with a rigid structure. First, the high-energy light energy is converted into heat energy. Then, the resin film acts as a heat insulation agent and adsorbs the debris particles generated under high-temperature laser cutting. After cutting and cleaning, the water-soluble film and the adsorbed debris particles are washed away by the DIW, thereby protecting the chip near the cutting path from heat damage and contamination.

[0027] Preferably, the water-soluble UV absorber comprises 2-phenylbenzimidazole-5-sulfonic acid and / or terephthalimide dicamphor sulfonic acid.

[0028] Preferably, the additives further include corrosion inhibitors.

[0029] Preferably, the corrosion inhibitor comprises any one or a combination of at least two of the following: a complex triallate, 1,2,4-triazole, phosphate ester, and borate ester. The corrosion inhibitor prevents corrosion of metallic components on the wafer.

[0030] Preferably, the leveling agent further includes acrylic polymers and / or ester polymers.

[0031] Preferably, the solvent comprises pure water and / or an alcohol ether solvent, and more preferably a combination of pure water and an alcohol ether solvent. The azeotropic system formed by water and an alcohol ether solvent helps to reduce the saturated vapor pressure of the system, thereby reducing volatility and providing excellent cooling performance.

[0032] Preferably, the alcohol ether solvent includes any one or a combination of at least two of isopropanol, ethanol, dipropylene glycol methyl ether, dipropylene glycol ethyl ether, ethylene glycol monomethyl ether, ethylene glycol tert-butyl ether, and propylene glycol monoethyl ether.

[0033] In a second aspect, the present invention provides a method for preparing a protective material resistant to high-power laser cutting as described in the first aspect, the method comprising the following steps:

[0034] The solvent and heat-resistant water-soluble resin in the formula are mixed, and then water-soluble UV absorber and additives are added and mixed again to obtain the protective material resistant to high-power laser cutting.

[0035] Preferably, the mixing speed is 600-1000 rpm, such as 600 rpm, 700 rpm, 800 rpm, 900 rpm, 1000 rpm, etc., and the mixing time is 1-5 hours, such as 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, etc.

[0036] Preferably, the remixing time is 1-2 hours, such as 1 hour, 1.5 hours, 2 hours, etc.

[0037] Preferably, the process of re-mixing further includes a filtering step.

[0038] Preferably, the filter element of the filter is 0.1-0.5μm, such as 0.1μm, 0.2μm, 0.3μm, 0.4μm, 0.5μm, etc.

[0039] Preferably, the filtration is performed at 0.1-0.5 MPa (e.g., 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, etc.).

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] The protective material provided by this invention comprises a combination of heat-resistant water-soluble resin, water-soluble UV absorber, additives, and solvents. Through the screening and synergistic compounding of specific components, especially the selection of heat-resistant water-soluble resin and additives, and further, the content and molecular weight of heat-resistant water-soluble resin are limited, so that the protective material has a high film thickness to provide heat insulation and adsorption, solves the problem of carbonization residue near the cutting path after high-power laser cutting, and has good leveling performance. Attached Figure Description

[0042] Figure 1 A process flow diagram showing the application of the protective material provided by this invention in laser cutting.

[0043] Figure 2-12 The images show the spin-coated film surfaces of the protective materials provided in Examples 1-7 and Comparative Examples 1-4, respectively, applied in the laser cutting process.

[0044] Figure 13-23 The protective materials provided in Examples 1-7 and Comparative Examples 1-4 were applied to the laser cutting process, and the results of cleaning showed whether there was carbonization residue on the cutting path. Detailed Implementation

[0045] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0046] Unless otherwise specified, the fluorocarbon surfactant used in the embodiments and comparative examples of this invention is DuPont Chemours Capstone FS-31 fluorocarbon surfactant, and the polysiloxane oligomer is BYK-345.

[0047] Example 1

[0048] This embodiment provides a protective material resistant to high-power laser cutting. The protective material, by weight percentage, comprises the following components: 12% water-soluble PET resin with a weight-average molecular weight of 9000; 3% polyvinylpyrrolidone with a weight-average molecular weight of 20000; 1% water-soluble UV absorber (2-phenylbenzimidazole-5-sulfonic acid); 0.5% fluorocarbon surfactant; 1% polysiloxane oligomer; 0.5% corrosion inhibitor (1,2,4-triazole); 15% dipropylene glycol methyl ether; and 67% pure water.

[0049] The preparation method includes the following steps:

[0050] (1) Weigh out pure water, dipropylene glycol methyl ether, water-soluble PET resin, and polyvinylpyrrolidone in sequence according to the above formula;

[0051] (2) Add the above components to the mixing tank and stir at 800 rpm for 3 hours;

[0052] (3) After the resin is completely dissolved, add water-soluble UV absorber, fluorocarbon surfactant, polysiloxane oligomer and corrosion inhibitor (1,2,4-triazole) in sequence, and stir for 1 hour;

[0053] (4) The protective material is obtained by filtering with a 0.5μm filter element.

[0054] Example 2

[0055] This embodiment provides a protective material resistant to high-power laser cutting. The protective material, by weight percentage, comprises the following components: 9% sodium polystyrene sulfonate with a weight-average molecular weight of 9000; 13% polyvinylpyrrolidone with a weight-average molecular weight of 20000; 3% water-soluble UV absorber (terephthalic acid dicamphor sulfonic acid); 1% fluorocarbon surfactant; 0.5% polysiloxane oligomer; 0.5% corrosion inhibitor (1,2,4-triazole); 15% dipropylene glycol ethyl ether; and 58% pure water.

[0056] The preparation method includes the following steps:

[0057] (1) Weigh out pure water, dipropylene glycol ethyl ether, sodium polystyrene sulfonate, and polyvinylpyrrolidone in sequence according to the above formula;

[0058] (2) Add the above components to the mixing tank and stir at 800 rpm for 3 hours;

[0059] (3) After the resin is completely dissolved, add water-soluble UV absorber, fluorocarbon surfactant, polysiloxane oligomer and corrosion inhibitor (1,2,4-triazole) in sequence, and stir for 1 hour;

[0060] (4) The protective material is obtained by filtering with a 0.5μm filter element.

[0061] Example 3

[0062] This embodiment provides a protective material resistant to high-power laser cutting. The protective material, by weight percentage, comprises the following components: 8% sodium polystyrene sulfonate with a weight-average molecular weight of 9000; 17% water-soluble PET resin with a weight-average molecular weight of 10000; 5% water-soluble UV absorber (terephthalamide dicamphor sulfonic acid); 1% fluorocarbon surfactant; 0.5% polysiloxane oligomer; 0.5% corrosion inhibitor (1,2,4-triazole); 15% dipropylene glycol ethyl ether; and 53% pure water.

[0063] The preparation method includes the following steps:

[0064] (1) Weigh out pure water, dipropylene glycol ethyl ether, sodium polystyrene sulfonate, and water-soluble PET resin in sequence according to the above formula;

[0065] (2) Add the above components to the mixing tank and stir at 800 rpm for 3 hours;

[0066] (3) After the resin is completely dissolved, add water-soluble UV absorber, fluorocarbon surfactant, polysiloxane oligomer and corrosion inhibitor (1,2,4-triazole) in sequence, and stir for 1 hour;

[0067] (4) The protective material is obtained by filtering with a 0.5μm filter element.

[0068] Example 4

[0069] This embodiment provides a protective material resistant to high-power laser cutting. The protective material, by weight percentage, comprises the following components: 10% sodium polystyrene sulfonate with a weight-average molecular weight of 12,000; 20% water-soluble PET resin with a weight-average molecular weight of 15,000; 1% water-soluble UV absorber (terephthalic acid dicamphor sulfonic acid); 0.4% fluorocarbon surfactant; 0.3% polysiloxane oligomer; 0.3% corrosion inhibitor (1,2,4-triazole); 15% dipropylene glycol ethyl ether; and 53% pure water.

[0070] The preparation method includes the following steps:

[0071] (1) Weigh out pure water, dipropylene glycol ethyl ether, sodium polystyrene sulfonate, and water-soluble PET resin in sequence according to the above formula;

[0072] (2) Add the above components to the mixing tank and stir at 800 rpm for 3 hours;

[0073] (3) After the resin is completely dissolved, add water-soluble UV absorber, fluorocarbon surfactant, polysiloxane oligomer and corrosion inhibitor (1,2,4-triazole) in sequence, and stir for 1 hour;

[0074] (4) The protective material is obtained by filtering with a 0.5μm filter element.

[0075] Example 5

[0076] This embodiment provides a protective material resistant to high-power laser cutting. The protective material, by weight percentage, comprises the following components: 8% sodium polystyrene sulfonate with a weight-average molecular weight of 15,000; 18% polyvinylpyrrolidone with a weight-average molecular weight of 50,000; 1% water-soluble UV absorber (terephthalic acid dicamphor sulfonic acid); 2% fluorocarbon surfactant; 1.5% polysiloxane oligomer; 1.5% corrosion inhibitor (1,2,4-triazole); 15% propylene glycol monoethyl ether; and 53% pure water.

[0077] The preparation method includes the following steps:

[0078] (1) Weigh out pure water, propylene glycol monoethyl ether, sodium polystyrene sulfonate, and polyvinylpyrrolidone in sequence according to the above formula;

[0079] (2) Add the above components to the mixing tank and stir at 800 rpm for 3 hours;

[0080] (3) After the resin is completely dissolved, add water-soluble UV absorber, fluorocarbon surfactant, polysiloxane oligomer and corrosion inhibitor (1,2,4-triazole) in sequence, and stir for 1 hour;

[0081] (4) The protective material is obtained by filtering with a 0.5μm filter element.

[0082] Example 6

[0083] The difference between this embodiment and Embodiment 1 is that the weight-average molecular weight of the water-soluble PET resin is 8000, while the rest are the same as in Embodiment 1.

[0084] Example 7

[0085] The difference between this embodiment and Embodiment 1 is that the weight-average molecular weight of the water-soluble PET resin is 17,000, while the rest are the same as in Embodiment 1.

[0086] Comparative Example 1

[0087] The difference between this comparative example and Example 1 is that the percentage of polyvinylpyrrolidone is 15%, and water-soluble PET resin is not added; all other aspects are the same as in Example 1.

[0088] Comparative Example 2

[0089] The difference between this comparative example and Example 1 is that no fluorocarbon surfactant is added, the percentage of polysiloxane oligomer is 1.5%, and the rest are the same.

[0090] Comparative Example 3

[0091] The difference between this comparative example and Example 2 is that the percentage of polyvinylpyrrolidone is 22%, and sodium polystyrene sulfonate is not added; all other aspects are the same.

[0092] Comparative Example 4

[0093] The difference between this comparative example and Example 1 is that no polysiloxane oligomer is added, the percentage of fluorocarbon surfactant is 1.5%, and all other aspects are the same.

[0094] The protective material prepared above was applied to a 10W laser cutting process, and the process flow diagram is as follows. Figure 1 As shown in Table 1, the obtained performance data are as follows.

[0095] Table 1

[0096]

[0097]

[0098]

[0099] As can be seen from Table 1, the protective materials provided in Examples 1-5 of the present invention are applied to the 10W laser cutting process. The spin-coated film surface is relatively flat. After high-power laser cutting and deionized water cleaning, there is no carbonization residue near the cutting path and basically no burrs.

[0100] The protective materials provided in Comparative Examples 1 and 3 failed to provide adequate protection during high-power laser cutting processes, resulting in severe carbonization residue near the cutting path and causing chip contamination. The protective materials in Comparative Examples 2 and 4 used a single leveling agent, and microscopic examination revealed poor leveling phenomena such as vortices and ripples on the film surface.

[0101] The applicant declares that this invention illustrates the protective material resistant to high-power laser cutting and its preparation method through the above embodiments, but this invention is not limited to the above embodiments, that is, it does not mean that this invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of the raw materials used in this invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of this invention.

Claims

1. A protective material resistant to high-power laser cutting, characterized in that, The protective material comprises the following components by weight percentage: Heat-resistant water-soluble resin 15-40%; Water-soluble UV absorber 1-5%; Additives 1-5%; Solvent 50-83%; The heat-resistant water-soluble resin is a combination of water-soluble PET and sodium polystyrene sulfonate, or a combination of water-soluble PET and polyvinylpyrrolidone, or a combination of sodium polystyrene sulfonate and polyvinylpyrrolidone. The weight-average molecular weights of the water-soluble PET and the sodium polystyrene sulfonate are each independently 9000-15000; The weight-average molecular weight of the polyvinylpyrrolidone is 20,000-50,000; The water-soluble UV absorber includes 2-phenylbenzimidazole-5-sulfonic acid and / or terephthalimide dicamphor sulfonic acid; The additives include leveling agents, which include fluorocarbon surfactants and polysiloxane oligomers; The protective material resistant to high-power laser cutting, wherein "high power" refers to a laser cutting process with a power of 10 W to 20 W.

2. The protective material for high-power laser cutting resistance according to claim 1, characterized in that, The additives also include corrosion inhibitors.

3. The protective material for high-power laser cutting resistance according to claim 2, characterized in that, The corrosion inhibitor includes any one or a combination of at least two of 1,2,4-triazole, phosphate ester, and borate ester.

4. The protective material for high-power laser cutting resistance according to claim 1, characterized in that, The leveling agent also includes acrylic polymers and / or ester polymers.

5. The protective material for high-power laser cutting resistance according to claim 1, characterized in that, The solvents include pure water and / or alcohol ether solvents.

6. The protective material for high-power laser cutting according to claim 5, characterized in that, The solvent includes a combination of pure water and alcohol ether solvents.

7. The protective material for high-power laser cutting according to claim 5, characterized in that, The alcohol ether solvents include any one or a combination of at least two of dipropylene glycol methyl ether, dipropylene glycol ethyl ether, ethylene glycol monomethyl ether, ethylene glycol tert-butyl ether, and propylene glycol monoethyl ether.

8. A method for preparing a protective material resistant to high-power laser cutting as described in any one of claims 1-7, characterized in that, The preparation method includes the following steps: The solvent and heat-resistant water-soluble resin in the formula are mixed, and then water-soluble UV absorber and additives are added and mixed again to obtain the protective material resistant to high-power laser cutting.

9. The preparation method according to claim 8, characterized in that, The mixing speed is 600-1000 rpm, and the mixing time is 1-5 h.

10. The preparation method according to claim 8, characterized in that, The remixing time is 1-2 hours.

11. The preparation method according to claim 8, characterized in that, The process of re-mixing also includes a filtering step.

12. The preparation method according to claim 11, characterized in that, The filter element used in the filtration process has a diameter of 0.1-0.5 μm.

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