A low-residue cleaning solution for chip packaging and a preparation method and application thereof

Abstract

This invention provides a low-residue chip packaging cleaning solution, its preparation method, and its application, belonging to the field of semiconductor packaging cleaning technology. The low-residue chip packaging cleaning solution, by weight percentage, consists of 20-40% main solvent, 5-12% amphoteric surfactant, 1.5-4% composite corrosion inhibitor, 3-8% co-solvent, 1-5% pH adjuster, and the balance deionized water. The main solvent is a compound of food-grade limonene and ethylene oxide-modified alcohol ether, and the composite corrosion inhibitor is a compound of benzotriazole derivative and nano-rare earth oxides. This invention, through unique component compounding and synergistic effects, simultaneously achieves high-efficiency cleaning, ultra-low ion residue (<10 ppb), excellent protection of copper / gold / silicon multi-substrate materials, and low VOC environmental protection characteristics, solving the technical problems of high toxicity, large residue, strong corrosiveness, and difficulty in balancing performance and environmental protection in traditional cleaning agents. The preparation process is simple and suitable for high-cleanliness cleaning of chip packages.

Description

Technical Field

[0001] This invention relates to the field of semiconductor packaging and electronic component cleaning technology, and in particular to a low-residue chip packaging cleaning solution, its preparation method and application. Background Technology

[0002] In chip packaging processes, cleaning is a critical step in removing flux, rosin residue, and particulate contaminants. Its cleanliness directly affects the chip's electrical performance and long-term reliability. Traditional cleaning methods often rely on organic solvents such as acetone, toluene, and trichloroethylene, which have the following main drawbacks: 1. Toxicity and environmental issues: Organic solvents have high levels of volatile organic compounds (VOCs) and are highly toxic, which endanger the health of operators and pollute the environment, and do not comply with increasingly stringent environmental regulations.

[0003] 2. Excessive ion residue: After cleaning, impurities such as chloride ions and sodium ions (usually >50ppb) may remain, which can easily lead to short circuits and leakage, reducing product yield.

[0004] 3. Poor substrate compatibility: It lacks effective protection for metal pins / pads such as copper and gold, which can easily cause corrosion and oxidation; at the same time, it may damage the surface energy of silicon wafers and affect the bonding strength of subsequent packaging processes.

[0005] 4. Difficulty in balancing cleaning efficiency and environmental protection: Although existing water-based cleaning agents attempt to reduce toxicity, they often have shortcomings in cleaning efficiency, substrate protection, or ion residue control, making it difficult to meet the high cleanliness requirements of high-end chip packaging.

[0006] Therefore, developing a chip packaging cleaning solution that combines high-efficiency cleaning, ultra-low ion residue, excellent substrate protection, and environmental friendliness has significant industrial application value and is a key technical problem that urgently needs to be solved in the field. Summary of the Invention

[0007] Purpose of the invention: This invention aims to overcome the aforementioned shortcomings of the prior art and provide a low-residue chip packaging cleaning solution, its preparation method, and its application. This cleaning solution, through a unique component formulation, achieves a synergistic effect of low VOC, low residue, strong substrate protection, and high cleaning efficiency.

[0008] The technical solution of the present invention: This invention discloses a low-residue chip packaging cleaning solution, which, by weight percentage (100%), comprises the following components: Main solvent: 20-40%; Amphoteric surfactants: 5-12%; Composite corrosion inhibitor: 1.5-4%; Cosolvent: 3-8%; pH adjuster: 1-5%; The remainder is deionized water; The main solvent is a mixture of food-grade limonene and ethylene oxide-modified alcohol ether solvent in a mass ratio of 1:0.8-1.5. The composite corrosion inhibitor is a compound of benzotriazole derivatives and nano-rare earth oxides in a mass ratio of 1:0.3-0.7.

[0009] In a further embodiment of this example, the ethylene oxide modified alcohol ether solvent is at least one of ethylene oxide modified propylene glycol methyl ether, ethylene oxide modified propylene glycol ethyl ether, or ethylene oxide modified ethylene glycol monobutyl ether.

[0010] In a further embodiment of this example, the amphoteric surfactant is sodium lauroyl sarcosinate or sodium cocoyl sarcosinate.

[0011] In a further embodiment of this example, the benzotriazole derivative is methylbenzotriazole or carboxybenzotriazole; the nano-rare earth oxide is at least one of cerium oxide, lanthanum oxide or praseodymium oxide with a particle size of 50-100 nm.

[0012] In a further embodiment of this example, the co-solvent is polyethylene glycol 400.

[0013] In a further embodiment of this example, the pH adjuster is a potassium dihydrogen phosphate and disodium hydrogen phosphate buffer pair, wherein the molar ratio of potassium dihydrogen phosphate to disodium hydrogen phosphate in the potassium dihydrogen phosphate and disodium hydrogen phosphate buffer pair is 1:1.2-1.8.

[0014] This invention provides a method for preparing a low-residue chip packaging cleaning solution, characterized by comprising the following steps: (1) Add the prescribed amount of deionized water to the reactor, turn on the stirrer, and stir at a speed of 300-400 r / min. Slowly add the pH adjuster and stir for 5-8 min until completely dissolved. Control the pH of the system to 6.5-8.5. (2) Keep the stirring rate constant, add the main solvent, heat to 30-35℃, and stir for 15-20 minutes until the system is homogeneous and transparent; (3) Cool down to 20-25℃, add amphoteric surfactant, increase the stirring speed to 500-600r / min, stir for 12-18min to ensure complete dispersion of surfactant; (4) Add the composite corrosion inhibitor and co-solvent in sequence. After each component is added, maintain stirring at 400-500 r / min for 8-10 min, and finally stir the whole mixture for 20-25 min. (5) Finally, filter through a microporous membrane to obtain a low-residue chip packaging cleaning solution, and seal it for later use.

[0015] In a further embodiment of this example, a 0.22-0.25 μm microporous membrane is used for filtration in step (5).

[0016] This invention provides an application of a low-residue chip packaging cleaning solution in cleaning chip packages.

[0017] In a further embodiment of this example, the application method includes: Step A: Rinse the chip package with room temperature deionized water for 2-3 minutes to remove surface dust and loose residue, then drain the water; Step B: Pour the prepared cleaning solution into a room temperature cleaning bath, ensuring that the chip package is completely submerged; Step C: Use 180-250W, 45kHz ultrasonic cleaning for 8-12 minutes; Step D: Rinse three times with ultrapure water with a conductivity of <1μs, each time for 4-5 minutes, to remove residual cleaning solution and ensure that no cleaning solution remains. Step E: Dry in a vacuum drying oven at 40-50℃ for 15-20 minutes, or at room temperature with ventilation for 30-40 minutes. After drying, the moisture content on the chip surface should be ≤0.1%.

[0018] This invention provides a primary solvent formulation for a low-residue chip packaging cleaning solution (food-grade limonene-ethylene oxide-modified propylene glycol methyl ether 1:0.8-1.5): Ethylene oxide modification optimizes the water solubility and dissolving power of propylene glycol methyl ether, synergistically with food-grade limonene to achieve a balance between low VOCs, low toxicity, and high efficiency in dissolving contaminants, resolving the contradiction between the high toxicity of traditional organic solvents and the insufficient cleaning power of water-based solvents. Precise selection of the amphoteric surfactant: Sodium lauroyl sarcosinate (purity ≥98.5%) possesses both strong penetrating power (surface tension ≤30mN / m) and low residue characteristics, enabling rapid removal of contaminants and easy removal by ultrapure water rinsing, avoiding excessive residual ions. The innovative composite corrosion inhibition system, benzotriazole derivative-rare earth cerium oxide 1:0.3-0.7, protects copper and gold metal substrates and silicon wafers through the dual action of "chemical adsorption film formation + physical barrier", solving the problem of limited protection range of single corrosion inhibitors; the particle size control of rare earth cerium oxide (50-100nm) ensures its uniform deposition on the substrate surface, improving the barrier effect.

[0019] Beneficial effects: This invention provides a low-residue chip packaging cleaning solution, which has the following significant advantages compared with the prior art: 1. Environmental protection and safety: It adopts a low-VOC main solvent compounding system with VOC content <50g / L, low toxicity, and meets environmental protection and occupational health standards.

[0020] 2. Ultra-low residue: The system is pure, and the total amount of residual ions (Cl) on the chip surface after cleaning is very low. - Na + ,K + ,Ca² + (etc.) can be controlled at <10ppb, which is far below the industry requirements.

[0021] 3. Superior substrate protection: The unique "chemical adsorption + physical barrier" composite corrosion inhibition system can effectively protect copper, gold and other metal substrates and silicon wafers at the same time, preventing corrosion and surface energy degradation, with a surface energy change rate of <5%.

[0022] 4. High-efficiency cleaning: The specific surfactants work synergistically with the main solvent to achieve a high removal rate (>97%) of contaminants such as rosin and flux, improving cleaning efficiency by more than 25% compared to traditional water-based cleaning agents.

[0023] 5. Good process compatibility: The preparation process is simple and the raw materials are readily available; the application process can be carried out at room temperature without modifying existing production lines, with low energy consumption, making it suitable for large-scale production. Detailed Implementation

[0024] The present invention will be described below with reference to specific embodiments. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.

[0025] Polyethylene glycol 400 was purchased from Shandong Qiyi Chemical Technology Co., Ltd.; food-grade limonene was purchased from Jinan Jiuzhouyuan Biotechnology Co., Ltd., d-limonene.

[0026] Unless otherwise specified, all chemical reagents used in this invention are commercially available analytical grade reagents.

[0027] Preparation of ethylene oxide-modified propylene glycol methyl ether: S1: Weigh out 90.12g of propylene glycol methyl ether, 7.97g of 30wt% potassium hydroxide aqueous solution, and 308.35g of ethylene oxide for later use; S2: Add propylene glycol methyl ether and 30wt% potassium hydroxide aqueous solution to the high-pressure reactor, close the reactor and check the seal; start stirring, heat to 105℃, open the vacuum to -0.095MPa, dehydrate for 35min, stop dehydration, close the vacuum, introduce nitrogen into the reactor to a pressure of 0.15MPa, slowly release the gas to atmospheric pressure, repeat 3 times; S3: Raise the temperature of the reactor to 120℃, keep the stirring stable, slowly introduce ethylene oxide, control the temperature inside the reactor at 120℃ and the pressure at 0.25MPa, control the ethylene oxide feeding time at 4h, after all the ethylene oxide has been introduced, maintain 120℃ and 0.25MPa, continue stirring and maturing for 60min, until the pressure inside the reactor no longer drops and the reaction is complete; S4: Cool the material in the reactor to 70°C, and slowly add glacial acetic acid while stirring until the pH value of the system reaches 7 and neutralization is complete. Transfer the neutralized material to the devolatilization device, control the temperature at 105°C and the vacuum degree at -0.095MPa, and perform vacuum devolatilization for 30 minutes. Filter the devolatilized material through a precision filter to remove trace amounts of salt impurities, and obtain ethylene oxide modified propylene glycol methyl ether.

[0028] Example 1 Raw material ratio (weight percentage): main solvent (food-grade limonene and ethylene oxide modified propylene glycol methyl ether mixed at a mass ratio of 1:1.2) 30%, sodium lauroyl sarcosinate 8%, composite corrosion inhibitor system (methylbenzotriazole and cerium oxide at a mass ratio of 1:0.5, rare earth cerium oxide particle size 80nm) 2.5%, polyethylene glycol 400 5%, potassium dihydrogen phosphate and disodium hydrogen phosphate buffer pair (potassium dihydrogen phosphate and disodium hydrogen phosphate molar ratio of 1:1.2) 3%, deionized water 51.5%; A method for preparing a low-residue chip packaging cleaning solution includes the following steps: (1) Add the amount of deionized water specified in the formula to the reactor, start stirring at a speed of 400 r / min, slowly add the potassium dihydrogen phosphate and disodium hydrogen phosphate buffer pair (potassium dihydrogen phosphate and disodium hydrogen phosphate molar ratio 1:1.2), stir for 5 min until completely dissolved, and control the pH of the system to 8.3. (2) While maintaining the stirring rate, add the mixture of food-grade limonene and ethylene oxide-modified propylene glycol methyl ether at a mass ratio of 1:1.2, heat to 35°C, and stir for 15 minutes until the system is homogeneous and transparent. (3) Cool down to 25°C, add sodium lauroyl sarcosinate, increase the stirring speed to 600 r / min, stir for 12 min, and ensure that the surfactant is completely dispersed; (4) Add the mixture of methylbenzotriazole and rare earth cerium oxide with a particle size of 80nm in a mass ratio of 1:0.5, and polyethylene glycol 400 in sequence. After each addition of a component, maintain stirring at 500r / min for 8min, and finally stir the whole mixture for 20min. (5) Finally, the solution was filtered through a 0.22μm microporous membrane to obtain a low-residue chip packaging cleaning solution. It was sealed for later use. After filtration, the turbidity of the cleaning solution was tested according to the test method ISO 7027-1:2016 "Water quality - Determination of turbidity - Part 1: Optical turbidity meter method", and the turbidity was measured to be 2.8 NTU.

[0029] Example 2 Raw material ratio (weight percentage): main solvent (food-grade limonene and ethylene oxide modified propylene glycol methyl ether mixed at a mass ratio of 1:0.8) 20%, sodium lauroyl sarcosinate 12%, composite corrosion inhibitor system (carboxybenzotriazole and rare earth cerium oxide at a ratio of 1:0.3, cerium oxide particle size 60nm) 4%, polyethylene glycol 400 8%, potassium dihydrogen phosphate and disodium hydrogen phosphate buffer pair (potassium dihydrogen phosphate and disodium hydrogen phosphate molar ratio of 1:1.8) 2%, deionized water 54%; A method for preparing a low-residue chip packaging cleaning solution includes the following steps: (1) Add the amount of deionized water specified in the formula to the reactor, start stirring, and stir at a speed of 300 r / min. Slowly add the potassium dihydrogen phosphate and disodium hydrogen phosphate buffer pair (potassium dihydrogen phosphate and disodium hydrogen phosphate molar ratio 1:1.8), stir for 5 min until completely dissolved, and control the pH of the system to 6.8. (2) While maintaining the stirring rate, add the mixture of food-grade limonene and ethylene oxide-modified propylene glycol methyl ether at a mass ratio of 1:0.8, heat to 30°C, and stir for 20 minutes until the system is homogeneous and transparent. (3) Cool down to 25°C, add sodium lauroyl sarcosinate, increase the stirring speed to 500 r / min, stir for 18 min, and ensure that the surfactant is completely dispersed; (4) Add the mixture of carboxybenzotriazole and rare earth cerium oxide with a particle size of 60nm in a mass ratio of 1:0.3, and polyethylene glycol 400 in sequence. After each addition of a component, maintain stirring at 400r / min for 10min, and finally stir the whole mixture for 25min. (5) Finally, the solution was filtered through a 0.22μm microporous membrane to obtain a low-residue chip packaging cleaning solution. It was sealed for later use. After filtration, the turbidity of the cleaning solution was tested according to the test method ISO 7027-1:2016 "Water quality - Determination of turbidity - Part 1: Optical turbidity meter method", and the turbidity was measured to be 4.2 NTU.

[0030] Example 3 Raw material ratio (weight percentage): main solvent (food-grade limonene and ethylene oxide modified propylene glycol methyl ether mixed at a mass ratio of 1:1.5) 40%, sodium lauroyl sarcosinate 5%, composite corrosion inhibitor system (methylbenzotriazole and rare earth cerium oxide at a ratio of 1:0.7, cerium oxide particle size 100nm) 1.5%, polyethylene glycol 400 3%, potassium dihydrogen phosphate and disodium hydrogen phosphate buffer pair (potassium dihydrogen phosphate and disodium hydrogen phosphate molar ratio of 1:1) 5%, deionized water 45.5%; A method for preparing a low-residue chip packaging cleaning solution includes the following steps: (1) Add the amount of deionized water specified in the formula to the reactor, start stirring at a speed of 400 r / min, slowly add the potassium dihydrogen phosphate and disodium hydrogen phosphate buffer pair (potassium dihydrogen phosphate and disodium hydrogen phosphate molar ratio 1:1), stir for 5 min until completely dissolved, and control the pH of the system to 8.3. (2) Keep the stirring rate constant, add food-grade limonene and ethylene oxide modified propylene glycol methyl ether at a mass ratio of 1:1.5. The degree of polymerization of ethylene oxide in the ethylene oxide modified propylene glycol methyl ether is 5. Heat to 35°C and stir for 15 minutes until the system is uniform and transparent. (3) Cool down to 35°C, add sodium lauroyl sarcosinate, increase the stirring speed to 600 r / min, stir for 12 min, and ensure that the surfactant is completely dispersed; (4) Add methylbenzotriazole and rare earth cerium oxide in sequence at a ratio of 1:0.7, with cerium oxide particle size of 100 nm and polyethylene glycol 400. After each addition of a component, maintain stirring at 500 r / min for 8 min, and finally stir the whole mixture for 20 min. (5) Finally, the solution was filtered through a 0.22μm microporous membrane to obtain a low-residue chip packaging cleaning solution. It was sealed for later use. After filtration, the turbidity of the cleaning solution was tested according to the test method ISO 7027-1:2016 "Water quality - Determination of turbidity - Part 1: Optical turbidity meter method", and the turbidity was measured to be 2.8 NTU.

[0031] Example 4 The difference between this preparation example and Example 1 is that: Raw material ratio (weight percentage): main solvent (food-grade limonene and ethylene oxide modified propylene glycol methyl ether mixed at a mass ratio of 1:1) 35%, sodium lauroyl sarcosinate 10%, composite corrosion inhibitor system (carboxybenzotriazole and rare earth cerium oxide at a ratio of 1:0.4, cerium oxide particle size 70nm) 3%, polyethylene glycol 400 6%, potassium dihydrogen phosphate and disodium hydrogen phosphate buffer pair (potassium dihydrogen phosphate and disodium hydrogen phosphate molar ratio of 1:1.5) 4%, deionized water 42%; A method for preparing a low-residue chip packaging cleaning solution includes the following steps: (1) Add the prescribed amount of deionized water to the reactor, start stirring at a speed of 380 r / min, slowly add potassium dihydrogen phosphate and disodium hydrogen phosphate buffer pair, stir for 5 min until completely dissolved, and control the pH of the system to 7.5. (2) Keep the stirring rate constant, add food-grade limonene and ethylene oxide modified propylene glycol methyl ether in a mass ratio of 1:1, heat to 33°C, and stir for 16 minutes until the system is uniform and transparent. (3) Cool down to 35°C, add sodium lauroyl sarcosinate, increase the stirring speed to 580 r / min, stir for 14 min, and ensure that the surfactant is completely dispersed; (4) Add carboxybenzotriazole-rare earth cerium oxide 1:0.4 in sequence, cerium oxide particle size 70nm, and polyethylene glycol. After each addition of a component, maintain stirring at 460r / min for 9min, and finally stir the whole mixture for 23min. (5) Finally, the solution was filtered through a 0.22μm microporous membrane to obtain a low-residue chip packaging cleaning solution. It was sealed and stored for later use. After filtration, the turbidity of the cleaning solution was tested according to the test method ISO 7027-1:2016 "Water quality - Determination of turbidity - Part 1: Optical turbidity meter method", and the turbidity was measured to be 3.5 NTU.

[0032] Comparative Example 1 The difference between this preparation example and Example 1 is that: Replace "composite corrosion inhibitor system (mass ratio of methylbenzotriazole to rare earth cerium oxide 1:0.5, rare earth cerium oxide particle size 80nm)" in the raw materials with "methylbenzotriazole"; The preparation method of a low-residue chip packaging cleaning solution is the same as the preparation method and conditions in Example 1.

[0033] Comparative Example 2 The difference between this preparation example and Example 1 is that: Replace "potassium dihydrogen phosphate and disodium hydrogen phosphate buffer pair" in the raw materials with "triethanolamine"; The preparation method of a low-residue chip packaging cleaning solution is the same as the preparation method and conditions in Example 1.

[0034] Comparative Example 3 The difference between this preparation example and Example 1 is that: Raw material ratio (weight percentage): Main solvent (food grade limonene) 30%; The preparation method of a low-residue chip packaging cleaning solution is the same as the preparation method and conditions in Example 1.

[0035] The low-residue chip packaging cleaning solutions prepared in Examples 1-4 and Comparative Examples 1-3 were subjected to the following tests: 1. Cleaning efficiency test: Test subject: BGA packaged chip test sample with standardized rosin flux residue; Cleaning conditions: The sample was completely immersed in the cleaning solution and cleaned for 10 minutes at 25°C using an ultrasonic cleaner (power 200W, frequency 45kHz). Cleaning rate calculation (gravimetric method): After cleaning, the sample was rinsed with ultrapure water and dried with nitrogen. The mass change of the sample before and after cleaning was measured using a precision electronic balance (accuracy 0.01mg).

[0036] 2. Surface ion residue test: The test standard refers to IPC-TM-650 2.3.28 (Determination of surface ion residue of electronic components by ion chromatography) or equivalent method; Sample pretreatment (dynamic extraction): Place the cleaned and dried chip into a clean container and add a quantitative amount (e.g., 50 mL) of ultrapure water (resistivity ≥ 18.2 MΩ·cm). Place the container in a 40°C water bath and ultrasonically extract for 15 minutes to fully dissolve the surface soluble ions. Analyze the extract using an ion chromatograph (IC).

[0037] 3. Metal substrate compatibility (corrosion inhibition) test: Test samples: high-purity copper sheets (≥99.9%), gold-plated test pieces; Test method: Static immersion loss method; Test conditions: The metal sample with known initial mass is completely immersed in the cleaning solution and soaked at a constant temperature of 25°C for 60 minutes; Determination of mass change rate: The treated test pieces were dried to constant weight and weighed using a precision electronic balance; Calculation formula: Mass change rate (%) = [(mass after immersion - mass before immersion) / mass before immersion] × 100%. A value close to zero indicates excellent corrosion inhibition effect.

[0038] 4. Silicon wafer surface property testing: Test subject: Silicon wafer with native oxide layer (surface roughness Ra≤0.02μm before cleaning); Test method: The surface free energy (SFE) change was determined by the contact angle method; Test procedure: Using a contact angle measuring instrument, the static contact angles of the silicon wafer surface with ultrapure water and diiodomethane probe liquids were measured before and after cleaning at 25°C; the surface free energy and its components before and after cleaning were calculated using the Owens-Wendt-Rabel-Kaelble (OWRK) two-liquid method model. Calculation formula: Surface energy change rate (%) = |(Surface energy after cleaning - Surface energy before cleaning) / Surface energy before cleaning| × 100%.

[0039] 5. Subsequent process compatibility (bond strength) test: Test method: Shear strength test; Test procedure: Prepare two sets of identical chip / substrate samples. One set is treated with the cleaning solution of this invention, and the other set is not cleaned and serves as a blank control. The two sets of samples complete the subsequent chip bonding process under the same conditions. Using a push-pull force tester, apply shear force to the bonding point at a standard speed until failure, and record the maximum shear force value. Results evaluation: Calculate the bond strength retention rate of the cleaned sample relative to the uncleaned blank sample; Calculation formula: Strength retention rate (%) = (Average shear strength of cleaned sample / Average shear strength of uncleaned sample) × 100%, and a strength decrease of ≤1% is considered as no performance loss.

[0040] Table 1: Test Results Table As shown in Table 1 of the test results, the four embodiments 1-4 of this invention all met and exceeded the design targets in key indicators such as cleaning efficiency (>97.5%), ultra-low ion residue (<10ppb), excellent metal protection (copper corrosion rate <0.002%), and excellent substrate compatibility (surface energy change rate <5%), demonstrating balanced and excellent comprehensive performance. Comparative Example 1 (single corrosion inhibitor): Using only methylbenzotriazole, copper substrate corrosion was significantly aggravated (0.015%), and the surface energy change of the silicon wafer increased (8.5%). This proves that the combination of rare earth cerium oxide nanoparticles and benzotriazole derivatives has a crucial synergistic effect, and the physical barrier film can effectively compensate for the shortcomings of a single chemical adsorption film in long-term protection. Comparative Example 2 (alternative pH adjuster): Replacing the potassium dihydrogen phosphate and disodium hydrogen phosphate buffer pair with triethanolamine resulted in a comprehensive deterioration in performance. Rosin residue removal rate dropped significantly to 83.5%, total ion residue surged to 39.0 ppb, silicon wafer surface energy change rate rose to 11.0%, and bond strength retention rate dropped to 97.4%. The core reason is that the potassium dihydrogen phosphate and disodium hydrogen phosphate buffer pair can stably maintain the system pH at around 8.3, providing a suitable environment for the dispersion of sodium lauroyl sarcosinate surfactant and the dissolution of the main solvent. Triethanolamine, however, has weak buffering capacity, and the system pH fluctuates easily during cleaning, leading to uneven surfactant dispersion and decreased solubility of the main solvent. This not only reduces cleaning efficiency but also worsens the stability of the cleaning solution itself, generating additional ion residues, which in turn damages the silicon wafer surface properties and affects subsequent bonding processes. This demonstrates that a dedicated buffer pair is key to achieving a balance between efficient cleaning and low residue. Comparative Example 3 (single main solvent): Using only food-grade limonene without compounding with ethylene oxide-modified propylene glycol methyl ether resulted in a decrease in cleaning efficiency (92.1%), and deterioration in ion residue (13.3 ppb) and substrate protection performance. This confirms that the key invention is the synergistic improvement of solubility, cleaning uniformity, and final cleaning effect by the main solvent compound system.

[0041] This invention can also be implemented in various other ways. Without departing from the spirit and essence of this invention, those skilled in the art can make various corresponding changes and modifications according to this invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A low residue chip package cleaning solution, characterized by, The low-residue chip packaging cleaning solution, by weight percentage (100%), consists of the following components: Main solvent: 20-40%; Amphoteric surfactants: 5-12%; Composite corrosion inhibitor: 1.5-4%; Cosolvent: 3-8%; pH adjuster: 1-5%; The remainder is deionized water; The main solvent is a mixture of food-grade limonene and ethylene oxide-modified alcohol ether solvent in a mass ratio of 1:0.8-1.

5. The composite corrosion inhibitor is a compound of benzotriazole derivatives and nano-rare earth oxides in a mass ratio of 1:0.3-0.

7.

2. The cleaning solution for low residue chip package according to claim 1, wherein The ethylene oxide modified alcohol ether solvent is at least one of ethylene oxide modified propylene glycol methyl ether, ethylene oxide modified propylene glycol ethyl ether, or ethylene oxide modified ethylene glycol monobutyl ether.

3. The low-residue chip packaging cleaning solution according to claim 1, characterized in that, The amphoteric surfactant is sodium lauroyl sarcosinate or sodium cocoyl sarcosinate.

4. The low-residue chip packaging cleaning solution according to claim 1, characterized in that, The benzotriazole derivative is methylbenzotriazole or carboxybenzotriazole; the nano-rare earth oxide is at least one of cerium oxide, lanthanum oxide or praseodymium oxide with a particle size of 50-100 nm.

5. The low-residue chip packaging cleaning solution according to claim 1, characterized in that, The co-solvent is polyethylene glycol 400.

6. The low-residue chip packaging cleaning solution according to claim 1, characterized in that, The pH adjuster is a potassium dihydrogen phosphate and disodium hydrogen phosphate buffer pair, wherein the molar ratio of potassium dihydrogen phosphate to disodium hydrogen phosphate in the potassium dihydrogen phosphate and disodium hydrogen phosphate buffer pair is 1:1.2-1.

8.

7. The method for preparing the low-residue chip packaging cleaning solution according to any one of claims 1-6, characterized in that, Includes the following steps: (1) Add the prescribed amount of deionized water to the reactor, turn on the stirrer, and stir at a speed of 300-400 r / min. Slowly add the pH adjuster and stir for 5-8 min until completely dissolved. Control the pH of the system to 6.5-8.

5. (2) Keep the stirring rate constant, add the main solvent, heat to 30-35℃, and stir for 15-20 minutes until the system is homogeneous and transparent; (3) Cool down to 20-25℃, add amphoteric surfactant, increase the stirring speed to 500-600r / min, stir for 12-18min to ensure complete dispersion of surfactant; (4) Add the composite corrosion inhibitor and co-solvent in sequence. After each component is added, maintain stirring at 400-500 r / min for 8-10 min, and finally stir the whole mixture for 20-25 min. (5) Finally, filter through a microporous membrane to obtain a low-residue chip packaging cleaning solution, and seal it for later use.

8. The method for preparing the low-residue chip packaging cleaning solution according to claim 7, characterized in that, In step (5), a 0.22-0.25 μm microporous membrane is used for filtration.

9. The application of the low-residue chip packaging cleaning solution according to any one of claims 1-6 in cleaning chip packages.

10. The application of the low-residue chip packaging cleaning solution according to claim 9, characterized in that, The application method includes: Step A: Rinse the chip package with room temperature deionized water for 2-3 minutes to remove surface dust and loose residue, then drain the water; Step B: Pour the prepared cleaning solution into a room temperature cleaning bath, ensuring that the chip package is completely submerged; Step C: Use 180-250W, 45kHz ultrasonic cleaning for 8-12 minutes; Step D: Rinse three times with ultrapure water with a conductivity of <1μs, each time for 4-5 minutes, to remove residual cleaning solution and ensure that no cleaning solution remains. Step E: Dry in a vacuum drying oven at 40-50℃ for 15-20 minutes, or at room temperature with ventilation for 30-40 minutes. After drying, the moisture content on the chip surface should be ≤0.1%.

Images