High-yield wafer laser cutting protection liquid and preparation method thereof

Abstract

The invention relates to the technical field of semiconductor packaging, and discloses a high-yield wafer laser cutting protection liquid. Comprising the following raw materials in parts by weight: 8-30 parts of water-soluble acrylic resin, 0.5-5 parts of an ultraviolet absorbent, 5-20 parts of a PMA solvent, 0.1-2 parts of a water-soluble flatting agent, 0.1-3 parts of a wetting agent, 0.5-1 part of a silane coupling agent and 50-85 parts of ultrapure water. According to the high-yield wafer laser cutting protection liquid and the preparation method thereof, the water-soluble acrylic resin and the PMA solvent are selected, the water-soluble acrylic resin and the PMA solvent have good intersolubility, and the silane coupling agent is matched to promote combination between resin and solvent molecules, so that the compatibility of a system is enhanced; in the preparation process, the components are added according to a specific sequence and fully stirred, so that the components are uniformly dispersed, the formed protective film is compact and stable, local cracking or falling during cutting can be effectively avoided, edge fragmentation and surface scratches of the wafer are inhibited, and the protection effect is improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor packaging technology, specifically to a high-yield wafer laser cutting protective liquid and its preparation method. Background Technology

[0002] In advanced semiconductor packaging processes, wafer laser cutting is one of the core steps, which places stringent requirements on cutting precision and surface integrity. Laser cutting protective fluid is a multifunctional coating material designed specifically for wafer laser processing. Its main functions include: forming a uniform and dense protective film during the cutting process to buffer laser impact and inhibit wafer edge breakage, while removing micron-sized particles generated during cutting through lubrication and dynamic fluid action.

[0003] Traditional protective solutions typically consist of film-forming agents, solvent systems, and functional additives, forming a temporary protective layer on the wafer surface through physical adsorption or chemical bonding.

[0004] However, the protective fluids commonly used in existing laser cutting technologies have significant drawbacks: First, the compatibility between acrylic resin and organic solvents in traditional formulations is insufficient, leading to local cracking or peeling of the protective film during cutting, which cannot effectively suppress wafer edge breakage and surface scratches; second, the high-temperature environment generated during laser cutting can cause thermal decomposition of the protective fluid, releasing corrosive gases containing fluorine or sulfur. These gases condense on the wafer surface, forming micron-sized defects that directly affect device performance; in addition, the lubricity and dynamic flow design of existing protective fluids are unreasonable, and their viscosity parameters do not match the microfluidic dynamics during the cutting process, making it difficult to remove micron-sized particles generated during cutting in a timely manner, ultimately causing secondary damage on the wafer surface and resulting in a decrease in overall yield. Therefore, a high-yield wafer laser cutting protective fluid and its preparation method are proposed. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this invention provides a high-yield wafer laser cutting protective fluid and its preparation method. Through precise composition design and preparation process, it significantly improves the thermal stability, mechanical properties, and particle removal efficiency of the wafer laser cutting protective fluid. It also solves the problems of insufficient compatibility between acrylic resin and organic solvents, poor heat resistance, and unreasonable lubricity and dynamic flow design in traditional laser cutting protective fluids.

[0007] (II) Technical Solution

[0008] To achieve the aforementioned goal of significantly improving the thermal stability, mechanical properties, and particle removal efficiency of wafer laser cutting protective fluid through precise component design and preparation process, this invention provides the following technical solution: a high-yield wafer laser cutting protective fluid, comprising the following raw materials in the indicated mass ratios: 8-30 parts by weight of water-soluble acrylic resin, 0.5-5 parts by weight of ultraviolet absorber, 5-20 parts by weight of PMA solvent, 0.1-2 parts by weight of water-soluble leveling agent, 0.1-3 parts by weight of wetting agent, 0.5-1 parts by weight of silane coupling agent, and 50-85 parts by weight of ultrapure water.

[0009] Preferably, the water-soluble acrylic resin is sodium polyacrylate or potassium polyacrylate, with a molecular weight of 10,000 to 50,000 and a solubility of ≥95% at 25°C.

[0010] Preferably, the ultraviolet absorber is benzophenone-3 or 2-hydroxy-4-n-octyloxybenzophenone, with a maximum absorption wavelength range of 280-350 nm and a dispersion particle size ≤1 μm in the protective liquid.

[0011] Preferably, the PMA solvent is propylene glycol methyl ether or propylene glycol methyl ether acetate, with a boiling point range of 120-150°C, and a miscibility with water of ≥90% at 25°C.

[0012] Preferably, the water-soluble leveling agent is a polyether-modified polysiloxane with a surface tension adjustment range of 25–35 mN / m and a stable dispersion time in the protective liquid of ≥24 hours.

[0013] Preferably, the wetting agent is polyethylene glycol octyl ether or polyoxyethylene alkyl ether, with an HLB value of 8 to 12, and a dynamic wetting time in the protective liquid of ≤2 seconds.

[0014] Preferably, the silane coupling agent is γ-glycidoxypropyltrimethoxysilane or 3-aminopropyltriethoxysilane, and its coupling reaction activity temperature range in the protective solution is 40-60°C.

[0015] A method for preparing a high-yield wafer laser cutting protective solution includes the high-yield wafer laser cutting protective solution and further includes the following steps:

[0016] S1. Heat the ultrapure water to 40-60°C and stir at 200-400 rpm.

[0017] S2. Add water-soluble acrylic resin, PMA solvent and silane coupling agent to the solution prepared in step S1 in sequence, and stir continuously until completely dissolved to form a premixed solution.

[0018] S3. Add UV absorber, water-soluble leveling agent and wetting agent to the premix, and continue stirring until homogenized to obtain a mixture;

[0019] S4. Filter the mixture through a filter membrane with a pore size of 0.5 μm to obtain the final protective solution.

[0020] Preferably, the stirring time for S1 to S3 is 4-6 hours.

[0021] (III) Beneficial Effects

[0022] Compared with the prior art, the present invention provides a high-yield wafer laser cutting protective liquid and its preparation method, which has the following beneficial effects:

[0023] 1. This high-yield wafer laser cutting protective solution and its preparation method utilize water-soluble acrylic resin and PMA solvent, which have good miscibility. Furthermore, a silane coupling agent is added to promote the bonding between resin and solvent molecules, enhancing the system's compatibility. During preparation, the components are added in a specific order and thoroughly stirred to ensure uniform dispersion. The resulting protective film is dense and stable, effectively preventing localized cracking or detachment during cutting, thereby inhibiting wafer edge breakage and surface scratches, and improving the protective effect.

[0024] 2. This high-yield wafer laser cutting protective fluid and its preparation method utilize an ultraviolet absorber that absorbs the ultraviolet energy generated during laser cutting, reducing the impact of high temperatures on the protective fluid. The suitable boiling point of the PMA solvent reduces the risk of thermal decomposition and avoids the release of corrosive gases. Simultaneously, a water-soluble leveling agent regulates surface tension, and a wetting agent shortens the dynamic wetting time, optimizing the lubricity and dynamic flowability of the protective fluid. This allows for timely removal of micron-sized particles generated during cutting, preventing secondary damage and improving wafer yield. Attached Figure Description

[0025] Figure 1 This is a flowchart illustrating the preparation process of the high-yield wafer laser cutting protective solution of the present invention. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Please see Figure 1A high-yield wafer laser cutting protective solution comprises the following raw materials in the indicated mass ratios: 8-30 parts by weight of water-soluble acrylic resin, 0.5-5 parts by weight of ultraviolet absorber, 5-20 parts by weight of PMA solvent, 0.1-2 parts by weight of water-soluble leveling agent, 0.1-3 parts by weight of wetting agent, 0.5-1 parts by weight of silane coupling agent, and 50-85 parts by weight of ultrapure water.

[0028] A method for preparing a high-yield wafer laser cutting protective solution includes the high-yield wafer laser cutting protective solution and further includes the following steps:

[0029] S1. Heat the ultrapure water to 40-60°C and stir at 200-400 rpm.

[0030] S2. Add water-soluble acrylic resin, PMA solvent and silane coupling agent to the solution prepared in step S1 in sequence, and stir continuously until completely dissolved to form a premixed solution.

[0031] S3. Add UV absorber, water-soluble leveling agent and wetting agent to the premix, and continue stirring until homogenized to obtain a mixture;

[0032] S4. Filter the mixture through a filter membrane with a pore size of 0.5 μm to obtain the final protective solution.

[0033] Example 1:

[0034] This embodiment uses the lower values ​​of the proportions of each component to verify the feasibility of the basic formulation, and is applicable to wafer laser cutting scenarios with basic requirements for the performance of the protective fluid.

[0035] A high-yield wafer laser cutting protective solution is composed of the following raw materials in the indicated mass ratios: 8 parts by weight of water-soluble acrylic resin, 0.5 parts by weight of ultraviolet absorber, 5 parts by weight of PMA solvent, 0.1 parts by weight of water-soluble leveling agent, 0.1 parts by weight of wetting agent, 0.5 parts by weight of silane coupling agent, and 85 parts by weight of ultrapure water.

[0036] A method for preparing a high-yield wafer laser cutting protective solution includes the following steps:

[0037] S1. Heat 85 parts by weight of ultrapure water to 40°C and stir continuously at 200 rpm.

[0038] S2. Add 8 parts by weight of water-soluble acrylic resin, 5 parts by weight of PMA solvent and 0.5 parts by weight of silane coupling agent to the solution prepared in step S1 in sequence, and continue stirring until completely dissolved to form a premixed solution.

[0039] S3. Add 0.5 parts by weight of UV absorber, 0.1 parts by weight of water-soluble leveling agent and 0.1 parts by weight of wetting agent to the premix, and continue stirring until homogenized to obtain a mixture; wherein, the total stirring time from S1 to S3 is 4 hours.

[0040] S4. Filter the mixture through a filter membrane with a pore size of 0.5 μm to obtain the final protective solution.

[0041] Sodium polyacrylate was selected as the water-soluble acrylic resin. Its molecular weight is 10,000 and its solubility at 25°C is 95%.

[0042] Benzophenone-3 was selected as the ultraviolet absorber, with a maximum absorption wavelength range of 280–350 nm and a dispersion particle size of 1 μm in the protective solution.

[0043] Propylene glycol methyl ether was selected as the PMA solvent. Its boiling point range is 120-150℃, and its miscibility with water at 25℃ is 90%.

[0044] Polyether-modified polysiloxane was selected as a water-soluble leveling agent, with a surface tension adjustment range of 25–35 mN / m and a stable dispersion time in the protective solution of 24 hours.

[0045] Polyethylene glycol octyl ether was selected as the wetting agent, with an HLB value of 8 and a dynamic wetting time of 2 seconds in the protective solution.

[0046] γ-glycidyl etheroxypropyltrimethoxysilane was selected as the silane coupling agent, and its coupling reaction activity temperature range in the protective solution is 40–60 °C.

[0047] The protective liquid in this embodiment, through the basic ratio of raw materials, can form a basic protective film on the wafer surface, which can initially buffer laser shock and suppress edge breakage, making it suitable for initial testing or scenarios with basic requirements for cutting effect.

[0048] Example 2:

[0049] This embodiment uses the intermediate values ​​of the proportions of each component to balance the performance and cost of the protective liquid, making it suitable for conventional wafer laser cutting scenarios.

[0050] A high-yield wafer laser cutting protective solution is composed of the following raw materials in the indicated mass ratios: 20 parts by weight of water-soluble acrylic resin, 2.5 parts by weight of ultraviolet absorber, 10 parts by weight of PMA solvent, 1 part by weight of water-soluble leveling agent, 2 parts by weight of wetting agent, 0.75 parts by weight of silane coupling agent, and 60 parts by weight of ultrapure water.

[0051] A method for preparing a high-yield wafer laser cutting protective solution includes the following steps:

[0052] S1. Heat 60 parts by weight of ultrapure water to 50°C and stir continuously at 300 rpm.

[0053] S2. Add 20 parts by weight of water-soluble acrylic resin, 10 parts by weight of PMA solvent and 0.75 parts by weight of silane coupling agent to the solution prepared in step S1 in sequence, and continue stirring until completely dissolved to form a premixed solution.

[0054] S3. Add 2.5 parts by weight of UV absorber, 1 part by weight of water-soluble leveling agent and 2 parts by weight of wetting agent to the premix, and continue stirring until homogenized to obtain a mixture; wherein, the total stirring time from S1 to S3 is 5 hours.

[0055] S4. Filter the mixture through a filter membrane with a pore size of 0.5 μm to obtain the final protective solution.

[0056] Potassium polyacrylate was selected as the water-soluble acrylic resin. Its molecular weight is 30,000 and its solubility at 25°C is 97%.

[0057] 2-Hydroxy-4-n-octyloxybenzophenone was selected as the ultraviolet absorber, with a maximum absorption wavelength range of 280–350 nm and a dispersion particle size of 0.8 μm in the protective solution;

[0058] Propylene glycol methyl ether acetate was selected as the PMA solvent. Its boiling point range is 120-150℃, and its miscibility with water at 25℃ is 95%.

[0059] Polyether-modified polysiloxane was selected as a water-soluble leveling agent, with a surface tension adjustment range of 25–35 mN / m and a stable dispersion time of 30 hours in the protective solution;

[0060] Polyoxyethylene alkyl ether was selected as the wetting agent, with an HLB value of 10 and a dynamic wetting time of 1.5 seconds in the protective solution.

[0061] 3-Aminopropyltriethoxysilane was selected as the silane coupling agent, and its coupling reaction activity temperature range in the protective solution is 40–60 °C.

[0062] The protective liquid in this embodiment has balanced performance, and the protective film has good density and stability. It can effectively buffer laser shock and remove particles generated during cutting, making it suitable for most conventional wafer laser cutting needs.

[0063] Example 3:

[0064] This embodiment uses the upper limit of the proportion of each component to maximize the performance of the protective liquid, and is suitable for wafer laser cutting scenarios with high requirements for cutting accuracy and yield.

[0065] A high-yield wafer laser cutting protective solution is composed of the following raw materials in the indicated mass ratios: 30 parts by weight of water-soluble acrylic resin, 5 parts by weight of ultraviolet absorber, 20 parts by weight of PMA solvent, 2 parts by weight of water-soluble leveling agent, 3 parts by weight of wetting agent, 1 part by weight of silane coupling agent, and 40 parts by weight of ultrapure water.

[0066] A method for preparing a high-yield wafer laser cutting protective solution includes the following steps:

[0067] S1. Heat 40 parts by weight of ultrapure water to 60°C and stir continuously at 400 rpm.

[0068] S2. Add 30 parts by weight of water-soluble acrylic resin, 20 parts by weight of PMA solvent and 1 part by weight of silane coupling agent to the solution prepared in step S1 in sequence, and continue stirring until completely dissolved to form a premixed solution.

[0069] S3. Add 5 parts by weight of UV absorber, 2 parts by weight of water-soluble leveling agent and 3 parts by weight of wetting agent to the premix, and continue stirring until homogenized to obtain a mixture; wherein, the total stirring time from S1 to S3 is 6 hours.

[0070] S4. Filter the mixture through a filter membrane with a pore size of 0.5 μm to obtain the final protective solution.

[0071] Sodium polyacrylate was selected as the water-soluble acrylic resin. Its molecular weight is 50,000 and its solubility at 25°C is 98%.

[0072] Benzophenone-3 was selected as the ultraviolet absorber, with a maximum absorption wavelength range of 280–350 nm and a dispersion particle size of 0.5 μm in the protective solution.

[0073] Propylene glycol methyl ether was selected as the PMA solvent. Its boiling point range is 120-150℃, and its miscibility with water at 25℃ is 98%.

[0074] Polyether-modified polysiloxane was selected as a water-soluble leveling agent, with a surface tension adjustment range of 25–35 mN / m and a stable dispersion time in the protective solution of 36 hours.

[0075] Polyethylene glycol octyl ether was selected as the wetting agent, with an HLB value of 12 and a dynamic wetting time of 1 second in the protective solution.

[0076] γ-glycidyl etheroxypropyltrimethoxysilane was selected as the silane coupling agent, and its coupling reaction activity temperature range in the protective solution is 40–60 °C.

[0077] The protective liquid in this embodiment has a high content of each effective component, and the protective film formed has better mechanical properties and thermal stability. It can minimize wafer edge breakage and surface scratches, making it suitable for high-end wafer processing with stringent requirements for cutting quality.

[0078] Example 4:

[0079] This embodiment verifies the actual effect of the protective liquid in the above embodiments through experiments.

[0080] Sixty silicon wafers of the same specifications, 12 inches in diameter, were selected and randomly divided into an experimental group and a control group, with 30 wafers in each group.

[0081] The experimental group used the protective liquid prepared in Example 2, while the control group used the traditional laser cutting protective liquid. Cutting operations were carried out under the same laser cutting parameters of 50W laser power, 100mm / s cutting speed, and 50μm spot diameter. After cutting, the yield, edge breakage rate, and number of surface scratches of the two groups of wafers were detected.

[0082] Experimental procedure:

[0083] For the experimental group wafers, the protective liquid prepared in Example 2 was uniformly coated on the wafer surface before dicing, and the coating thickness was controlled at 5 μm; the control group wafers were coated with a conventional protective liquid, and the coating thickness was also 5 μm.

[0084] Then, the wafers are cut according to the set laser parameters. After the cutting is completed, the wafer edges are observed with an optical microscope at 500x magnification to see if there are any cracks. The number of wafers with cracked edges is counted and the edge cracking rate is calculated.

[0085] Surface profilometers were used to detect scratches on the wafer surface, and the number of scratches on each wafer was counted.

[0086] The number of wafers in each group that meet the quality standards (no edge breakage, no surface scratches ≤ 3) is counted, and the yield is calculated.

[0087] The experimental data are shown in the table below:

[0088]

[0089] The experimental data above show that the high-yield wafer laser cutting protective solution prepared in Example 2 of this application had an edge breakage rate of 6.7%, which is much lower than the 33.3% of the control group; the average number of scratches per wafer was 1.17, which is significantly less than the 4 scratches of the control group; and the yield reached 93.3%, which is significantly higher than the 70% of the control group. This indicates that the high-yield wafer laser cutting protective solution of this application can effectively reduce the edge breakage rate and the number of surface scratches during the wafer laser cutting process, and greatly improve the wafer cutting yield, thus verifying the feasibility and effectiveness of the technical solution of this application.

[0090] In summary, this high-yield wafer laser cutting protective solution and its preparation method utilize water-soluble acrylic resin and PMA solvent, which have good miscibility. The addition of a silane coupling agent further promotes the bonding between resin and solvent molecules, enhancing the system's compatibility. During preparation, the components are added in a specific order and thoroughly stirred to ensure uniform dispersion, resulting in a dense and stable protective film. This effectively prevents localized cracking or detachment during cutting, thereby inhibiting wafer edge breakage and surface scratches, and improving the protective effect.

[0091] Furthermore, this high-yield wafer laser cutting protective fluid and its preparation method utilize an ultraviolet absorber that absorbs the ultraviolet energy generated during laser cutting, reducing the impact of high temperatures on the protective fluid. The suitable boiling point of the PMA solvent reduces the risk of thermal decomposition and avoids the release of corrosive gases. Simultaneously, a water-soluble leveling agent regulates surface tension, and a wetting agent shortens the dynamic wetting time, optimizing the lubricity and dynamic flowability of the protective fluid. This allows for the timely removal of micron-sized particles generated during cutting, preventing secondary damage and improving wafer yield. It solves the problems of insufficient compatibility between acrylic resin and organic solvents, poor heat resistance, and unreasonable design of lubricity and dynamic flowability in traditional laser cutting protective fluids.

[0092] The relevant modules involved in this system are all hardware system modules or functional modules that combine computer software programs or protocols with hardware in the prior art. The computer software programs or protocols involved in these functional modules are technologies known to those skilled in the art and are not improvements to this system. The improvement of this system lies in the interaction or connection between the modules, that is, in improving the overall structure of the system to solve the corresponding technical problems that this system aims to address.

[0093] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-yield wafer laser cutting protective fluid, characterized in that, The raw materials include the following proportions: 8-30 parts by weight of water-soluble acrylic resin, 0.5-5 parts by weight of UV absorber, 5-20 parts by weight of PMA solvent, 0.1-2 parts by weight of water-soluble leveling agent, 0.1-3 parts by weight of wetting agent, 0.5-1 parts by weight of silane coupling agent, and 50-85 parts by weight of ultrapure water.

2. The high-yield wafer laser cutting protective fluid according to claim 1, characterized in that, The water-soluble acrylic resin is sodium polyacrylate or potassium polyacrylate, with a molecular weight of 10,000 to 50,000 and a solubility of ≥95% at 25°C.

3. The high-yield wafer laser cutting protective fluid according to claim 1, characterized in that, The ultraviolet absorber is benzophenone-3 or 2-hydroxy-4-n-octyloxybenzophenone, with a maximum absorption wavelength range of 280-350 nm and a dispersion particle size ≤1 μm in the protective solution.

4. The high-yield wafer laser cutting protective fluid according to claim 1, characterized in that, The PMA solvent is propylene glycol methyl ether or propylene glycol methyl ether acetate, with a boiling point range of 120–150 °C, and a miscibility of ≥90% with water at 25 °C.

5. The high-yield wafer laser cutting protective fluid according to claim 1, characterized in that, The water-soluble leveling agent is a polyether-modified polysiloxane with a surface tension adjustment range of 25–35 mN / m and a stable dispersion time in the protective liquid of ≥24 hours.

6. The high-yield wafer laser cutting protective fluid according to claim 1, characterized in that, The wetting agent is polyethylene glycol octyl ether or polyoxyethylene alkyl ether, with an HLB value of 8 to 12, and a dynamic wetting time of ≤2 seconds in the protective liquid.

7. The high-yield wafer laser cutting protective fluid according to claim 1, characterized in that, The silane coupling agent is γ-glycidoxypropyltrimethoxysilane or 3-aminopropyltriethoxysilane, and its coupling reaction activity temperature range in the protective solution is 40-60℃.

8. A method for preparing a high-yield wafer laser cutting protective solution, characterized in that, The high-yield wafer laser cutting protective solution according to claims 1-7 further includes the following steps: S1. Heat the ultrapure water to 40-60°C and stir at 200-400 rpm. S2. Add water-soluble acrylic resin, PMA solvent and silane coupling agent to the solution prepared in step S1 in sequence, and stir continuously until completely dissolved to form a premixed solution. S3. Add UV absorber, water-soluble leveling agent and wetting agent to the premix, and continue stirring until homogenized to obtain a mixture; S4. Filter the mixture through a filter membrane with a pore size of 0.5 μm to obtain the final protective solution.

9. The method for preparing a high-yield wafer laser cutting protective solution according to claim 8, characterized in that, The stirring time for S1 to S3 is 4-6 hours.

Images