A semiconductor post-encapsulation cleaning agent and a preparation method thereof

Abstract

The application discloses a kind of semiconductor package post-cleaning agent and preparation method thereof, belong to semiconductor manufacturing and cleaning technical field.The cleaning agent is composed of alcohol ether solvent A, alcohol ether solvent B, low-foaming nonionic surfactant, isomeric alcohol ether surfactant, chelating agent, copper corrosion inhibitor, pH regulator and deionized water.By the synergistic effect between alcohol ether solvent and the compounding of surfactant, the cleaning agent has very low foam level in the spraying process, the cleaning of residual flux is thorough, the pH is neutral, the corrosion of sensitive metal is very low, the ion residue and non-volatile residue on the surface of the device after cleaning are very low, it can pass through the severe high temperature and high humidity reverse bias test, meet the cleaning requirements of high reliability semiconductor packaging device, and the preparation process is simple, suitable for industrial production.

Description

Technical Field

[0001] This invention relates to the fields of semiconductor manufacturing and cleaning technology, and in particular to a post-packaging cleaning agent for semiconductors and its preparation method. Background Technology

[0002] With the rapid development of emerging technologies such as AI, 5G, IoT, and new energy vehicles, the semiconductor industry is increasingly demanding higher integration, reliability, and precision in its devices. In semiconductor packaging processes, flux, as a key auxiliary material in the soldering process, inevitably leaves residues on the device surface and in the fine gaps after soldering. These residues mainly include rosin / resin solid components, organic acid / halide activator systems, and oxides and microparticles from the solder paste. If not completely removed, ionic contaminants in the residues may cause electrochemical migration and increased leakage current under high temperature and humidity conditions, leading to device failure; while non-polar resin residues will affect the adhesion of subsequent molding and other processes, seriously threatening the long-term reliability of packaged devices.

[0003] Currently, post-packaging cleaning technology in the semiconductor industry still primarily relies on acidic and alkaline water-based cleaning agents. While acidic cleaning agents are highly effective at removing metal oxides, they can easily corrode sensitive metals such as aluminum, copper, nickel, and silver in semiconductor devices. Alkaline cleaning agents, although possessing strong saponification capabilities, also pose a risk of corrosion to various sensitive metals. To overcome these issues, the development of neutral water-based cleaning agents has been proposed. Existing technologies include cleaning agent compositions that combine gemini surfactants with nonionic surfactants and alcohol ether solvents. However, in such solutions, the dynamic foam height of the gemini surfactants under spray conditions is typically high, resulting in prolonged defoaming time and insufficient foam control, easily leading to problems such as overflow of the cleaning solution and decreased cleaning efficiency. Other solutions use alcohol ether solvents as the main agent, combined with organic amines and imidazoline corrosion inhibitors. However, organic amine components pose a significant corrosion risk to sensitive metals such as aluminum and copper, and organic amines themselves tend to remain on the device surface, increasing non-volatile residues that may affect the adhesion of subsequent processes, making it difficult to meet the requirements of high-reliability packaging. Overall, existing neutral water-based cleaning agents struggle to achieve multiple properties such as low foaming, corrosion inhibition, and low residue while ensuring cleaning power.

[0004] Therefore, developing a post-semiconductor packaging cleaning agent that meets the requirements of spray cleaning processes, has excellent cleaning effect, low foaming properties, neutral pH, high compatibility with sensitive materials, and can pass stringent reliability tests has significant application value. Summary of the Invention

[0005] The purpose of this invention is to provide a post-semiconductor packaging cleaning agent and its preparation method. This cleaning agent can maintain an extremely low foam level in the spray cleaning process, achieve excellent flux residue removal effect, and has excellent compatibility with sensitive metal materials such as aluminum, copper, nickel, and silver, meeting the requirements for use in high-reliability packaged devices.

[0006] To achieve the above objectives, the present invention provides a post-semiconductor packaging cleaning agent, comprising the following components by mass percentage: 18-28% alcohol ether solvent A, 6-12% alcohol ether solvent B, 3-6% low-foaming nonionic surfactant, 2.5-5% isomeric alcohol ether surfactant, 0.8-2.5% chelating agent, 0.08-0.2% copper corrosion inhibitor, 0.2-0.8% pH adjuster, with the balance being deionized water.

[0007] Preferably, the alcohol ether solvent A is propylene glycol methyl ether and / or dipropylene glycol methyl ether; the alcohol ether solvent B is one or more of dipropylene glycol butyl ether, propylene glycol butyl ether, and diethylene glycol butyl ether; the mass ratio of alcohol ether solvent A to alcohol ether solvent B is 2.5:1 to 4:1.

[0008] Preferably, the alcohol ether solvent A is a compound of propylene glycol methyl ether and dipropylene glycol methyl ether in a mass ratio of 2:1 to 5:1; and the alcohol ether solvent B is dipropylene glycol butyl ether.

[0009] Preferably, the low-foaming nonionic surfactant has the structural formula RO-(CH2CH2O). n -H, where R is a C8~C10 straight-chain or branched alkyl group, n=3~5, and HLB value is 7~10.

[0010] Preferably, the structural formula of the isomeric alcohol ether surfactant is R'-O-(CH2CH2O). m -H, where R' is a C10~C13 branched alkyl group with a branching degree ≥60%, m=5~8, and HLB value 12~14.

[0011] Preferably, the chelating agent is a compound of disodium ethylenediaminetetraacetate and hydroxyethylidene diphosphonic acid in a mass ratio of 1:1 to 3:1.

[0012] Preferably, the copper corrosion inhibitor is benzotriazole.

[0013] Preferably, the pH adjuster is a compound buffer pair of citric acid and sodium citrate with a mass ratio of 1:1.5 to 1:2.5.

[0014] This invention also provides a method for preparing the above-mentioned semiconductor packaging cleaning agent, comprising the following steps: S1. Add 30% to 50% of the total amount of deionized water to the reactor and heat it to 25 to 45°C. S2. While stirring at 200-400 rpm, add alcohol ether solvent A, alcohol ether solvent B, low-foaming nonionic surfactant, and isomeric alcohol ether surfactant to the reactor in sequence, stirring for 3-5 minutes after each addition. S3. Under stirring conditions, add chelating agent and copper corrosion inhibitor to the reactor and continue stirring for 5-10 minutes. S4. Under stirring conditions, add pH adjuster to the reactor and stir until homogeneous; S5. While stirring at 300-500 rpm, add the remaining deionized water at a rate of 50-200 g / min, controlling the system temperature to not exceed 50℃. After the addition is complete, continue stirring for 15-30 minutes until the solution is transparent and homogeneous. S6. Let stand for 10-20 minutes to defoam, then filter through a 0.45μm filter to obtain the semiconductor packaging cleaning agent.

[0015] Therefore, the semiconductor packaging cleaning agent and its preparation method provided by this invention, through the synergistic effect of alcohol ether solvent A and alcohol ether solvent B within a specific ratio range, the optimized compounding of two surfactants, and the combined action of compound chelating agents, buffer pairs, and corrosion inhibitors, enables the cleaning agent to have excellent low-foaming performance under spraying conditions, high-efficiency cleaning ability for flux residues, and excellent compatibility with sensitive metal materials such as copper, aluminum, and nickel. After cleaning, the ionic contaminants, halide ions, and non-volatile residues on the device surface are all at extremely low levels. It can pass the high temperature and high humidity reverse bias test, meeting the comprehensive requirements of high-reliability semiconductor packaging devices for low-foaming, high-efficiency cleaning, material compatibility, ultra-low residues, and reliability of the cleaning agent. At the same time, the preparation method has high tolerance to temperature and water addition rate, making it suitable for large-scale industrial production.

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0017] Figure 1 This is a schematic flowchart of a method for preparing a cleaning agent after semiconductor packaging according to the present invention; Figure 2 This is a comparison chart of the cleaning rate and ionic contaminant (NaCl equivalent) tests in the embodiments and comparative examples of the present invention. Detailed Implementation

[0018] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention should be considered equivalent substitutions and are included within the protection scope of the present invention. Furthermore, it should be understood that after reading the contents of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims and are all within the protection scope of the present invention.

[0019] In this document, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The term "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment, nor does it specifically limit its independence or connection with other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.

[0020] Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the use of related terms herein is merely for the purpose of describing particular embodiments and is not intended to limit this application.

[0021] Unless otherwise specified, the materials, reagents, instruments, and equipment used in this invention are all materials, reagents, instruments, and equipment routinely used by those skilled in the art, and the testing standards all use national or international standards commonly used in the field, without further explanation.

[0022] This invention provides a cleaning agent for semiconductor packaging, which is composed of the following components by mass percentage: 18-28% alcohol ether solvent A, 6-12% alcohol ether solvent B, 3-6% low-foaming nonionic surfactant, 2.5-5% isomeric alcohol ether surfactant, 0.8-2.5% chelating agent, 0.08-0.2% copper corrosion inhibitor, 0.2-0.8% pH adjuster, and the balance being deionized water.

[0023] In this invention, alcohol ether solvent A is selected from one or a combination of two of propylene glycol methyl ether (PGME) and dipropylene glycol methyl ether (DPM), preferably a mixture of PGME and DPM in a mass ratio of 2:1 to 5:1. Alcohol ether solvent A has a moderate hydrophilic-lipophilic balance value (HLB approximately 10-12), and has good dissolving ability for polar organic acids and inorganic salt residues in the flux. Alcohol ether solvent B is selected from one or more of dipropylene glycol butyl ether (DPNB), propylene glycol butyl ether (PNB), and diethylene glycol butyl ether (DB), preferably DPNB. Alcohol ether solvent B has stronger hydrophobicity (HLB approximately 7-8), and has good dissolving and swelling ability for non-polar or weakly polar rosin / resin components in the flux. Within the dosage range specified in this invention, there is a significant synergistic effect between alcohol ether solvent A and alcohol ether solvent B. The strongly polar groups of alcohol ether solvent A can disrupt the intermolecular forces between the polar and nonpolar interfaces in the flux, making it easier for alcohol ether solvent B to penetrate into the deep regions of the rosin resin cross-linked network, achieving comprehensive dissolution from the surface to the depths and from polar to nonpolar components. When the amount of alcohol ether solvent B is excessive, the surface tension of the cleaning agent increases, its penetration ability into micro-gap decreases, and the cleaning rate decreases; when the amount of alcohol ether solvent B is too low, the swelling and peeling effect on the rosin resin is significantly weakened, and the cleaning rate also decreases.

[0024] In this invention, the structural formula of the low-foaming nonionic surfactant is RO-(CH2CH2O). n -H, where R is a C8-C10 straight-chain or branched alkyl group, n=3-5, and HLB value 7-10. This surfactant can significantly reduce the dynamic surface tension of cleaning solutions and enhance its wetting and emulsifying dispersion ability on contaminant surfaces. The structural formula of the isomeric alcohol ether surfactant is R'-O-(CH2CH2O). m -H, where R' is a C10~C13 branched alkyl group with a branching degree ≥60%, m=5~8, and HLB value 12~14. The branching degree is defined as the molar percentage of branched carbon atoms to the total number of carbon atoms, obtained by... 13 C-NMR determination. A branching degree of ≥60% means that more than 60% of the carbon atoms in the molecule are located in the branched structure, which endows the surfactant with extremely low dynamic surface tension and rapid penetration ability.

[0025] In this invention, the chelating agent is a compound of disodium ethylenediaminetetraacetate (EDTA-2Na) and hydroxyethylidene diphosphonic acid (HEDP) in a mass ratio of 1:1 to 3:1. EDTA has a chelating effect on Ca... 2+ Mg 2+ Alkaline earth metal ions exhibit high chelation stability constants, while HEDP has a high chelation stability constant for Fe. 3+ Cu 2+Transition metal ions exhibit stronger coordination ability, and the combined use of these two agents achieves a wider range of metal ion capture and higher chelation capacity, resulting in a significant synergistic effect in reducing ion residue. The copper corrosion inhibitor is benzotriazole (BTA), which forms a chemisorption film on the copper surface to inhibit corrosion. The pH adjuster is a buffer pair of citric acid and sodium citrate, with a mass ratio of 1:1.5 to 1:2.5. This buffer system can precisely control the pH of the cleaning agent within a neutral range of 6.5 to 7.5.

[0026] like Figure 1 As shown, the present invention also provides a method for preparing the above-mentioned semiconductor packaging cleaning agent, specifically including the following steps: S1. Add 30% to 50% of the total amount of deionized water to the reactor and heat it to 25 to 45°C.

[0027] S2. While stirring at 200-400 rpm, add alcohol ether solvent A, alcohol ether solvent B, low-foaming nonionic surfactant, and isomeric alcohol ether surfactant to the reactor in sequence, stirring for 3-5 minutes after each addition; this sequence avoids the emulsification risk of directly adding water to a high-concentration solvent system.

[0028] S3. Under stirring conditions, add chelating agent and copper corrosion inhibitor to the reactor and continue stirring for 5-10 minutes.

[0029] S4. Under stirring conditions, add pH adjuster to the reactor and stir until homogeneous.

[0030] S5. While stirring at 300-500 rpm, add the remaining deionized water at a rate of 50-200 g / min, controlling the system temperature to not exceed 50℃. After the addition is complete, continue stirring for 15-30 minutes until the solution is transparent and homogeneous.

[0031] S6. Let stand for 10-20 minutes to defoam, then filter through a 0.45μm filter to obtain the semiconductor packaging cleaning agent.

[0032] It should be noted that, in the process diagram, for the sake of simplification, beaker icons are used instead of reaction vessels to represent the mixing containers for each step, which does not affect the implementation of the actual technical solution.

[0033] The low-foaming nonionic surfactant used in the following examples and comparative examples is JC-801 (C8~C10, n≈4, HLB≈9); the isomeric alcohol ether surfactant used is Lutensol XP 60 (C10~C13 branched, branching degree ≥70%, m≈6, HLB≈13).

[0034] Example 1 This embodiment provides a post-semiconductor packaging cleaning agent, which is composed of the following components by mass percentage: 18.0% propylene glycol methyl ether, 5.0% dipropylene glycol methyl ether, 8.0% dipropylene glycol butyl ether, 4.0% low-foaming nonionic surfactant (JC-801), 3.0% isomeric alcohol ether surfactant (Lutensol XP 60), 1.0% EDTA-2Na, 0.5% HEDP, 0.10% benzotriazole, 0.15% citric acid, 0.30% sodium citrate, and the balance being deionized water (59.95%).

[0035] The preparation method is as follows: 40% of the total deionized water is added to the reactor, and the temperature is raised to 35℃. PGME, DPM, DPNB, JC-801, and Lutensol XP 60 are added sequentially under stirring at 200 rpm, stirring for 3 minutes after each addition. EDTA-2Na, HEDP, and BTA are then added, and stirred for 5 minutes; citric acid and sodium citrate are added, and stirred for 5 minutes. The remaining deionized water is added at a rate of 100 g / min, controlling the temperature to ≤45℃, and stirred for 20 minutes until transparent. After standing for 15 minutes, the solution is filtered through a 0.45 μm filter to obtain the semiconductor packaging cleaning agent.

[0036] Example 2 This embodiment provides a cleaning agent for semiconductor packaging, which is composed of the following components by mass percentage: 14.0% propylene glycol methyl ether, 4.0% dipropylene glycol methyl ether, 7.2% dipropylene glycol butyl ether, 4.0% low-foaming nonionic surfactant (JC-801), 3.0% isomeric alcohol ether surfactant (Lutensol XP 60), 1.2% EDTA-2Na, 0.4% HEDP, 0.12% benzotriazole, 0.20% citric acid, 0.40% sodium citrate, and the balance being deionized water (65.48%).

[0037] The preparation method is the same as in Example 1.

[0038] Example 3 This embodiment provides a post-semiconductor packaging cleaning agent, which is composed of the following components by mass percentage: 20.0% propylene glycol methyl ether, 8.0% dipropylene glycol methyl ether, 7.0% dipropylene glycol butyl ether, 3.5% low-foaming nonionic surfactant (JC-801), 3.5% isomeric alcohol ether surfactant (Lutensol XP 60), 1.5% EDTA-2Na, 0.5% HEDP, 0.09% benzotriazole, 0.18% citric acid, 0.35% sodium citrate, and the balance being deionized water (55.38%).

[0039] The preparation method is the same as in Example 1.

[0040] Example 4 This embodiment provides a post-semiconductor packaging cleaning agent, which is composed of the following components by mass percentage: 18.0% propylene glycol methyl ether, 5.0% dipropylene glycol methyl ether, 8.0% dipropylene glycol butyl ether, 3.0% low-foaming nonionic surfactant (JC-801), 3.0% isomeric alcohol ether surfactant (Lutensol XP 60), 1.0% EDTA-2Na, 0.5% HEDP, 0.10% benzotriazole, 0.15% citric acid, 0.30% sodium citrate, and the balance being deionized water (60.95%).

[0041] The preparation method is the same as in Example 1.

[0042] Example 5 This embodiment provides a post-semiconductor packaging cleaning agent, which is composed of the following components by mass percentage: 18.0% propylene glycol methyl ether, 5.0% dipropylene glycol methyl ether, 8.0% dipropylene glycol butyl ether, 5.0% low-foaming nonionic surfactant (JC-801), 2.5% isomeric alcohol ether surfactant (Lutensol XP 60), 1.0% EDTA-2Na, 0.5% HEDP, 0.10% benzotriazole, 0.15% citric acid, 0.30% sodium citrate, and the balance being deionized water (59.45%).

[0043] The preparation method is the same as in Example 1.

[0044] Example 6 This embodiment provides a cleaning agent for semiconductor packaging, using the exact same formulation as in Example 1, except for the process parameters in the preparation method: 40% of the total deionized water is added to the reactor and heated to 40°C; the remaining deionized water is added at a rate of 150 g / min, and the system temperature rises to a maximum of 47°C; the remaining steps are the same as in Example 1.

[0045] Example 7 This embodiment provides a cleaning agent for semiconductor packaging, using the exact same formulation as in Example 1, except for the process parameters in the preparation method: the remaining deionized water is added at a rate of 200 g / min, the system temperature instantly rises to 49°C, and then stabilizes below 45°C; the remaining steps are the same as in Example 1.

[0046] Comparative Example 1 This comparative example provides a cleaning agent for semiconductor packaging, which differs from Example 1 in that: dipropylene glycol butyl ether is not added, and the amount of deionized water is increased accordingly to 67.95%, while the rest are the same as in Example 1.

[0047] Comparative Example 2 This comparative example provides a cleaning agent for semiconductor packaging, which differs from Example 1 in that: no low-foaming nonionic surfactant is added, and the amount of isomeric alcohol ether surfactant is increased to 7.0%, while the rest are the same as in Example 1.

[0048] Comparative Example 3 This comparative example provides a cleaning agent for semiconductor packaging, which differs from Example 1 in that: no isomeric alcohol ether surfactant is added, and the amount of low-foaming nonionic surfactant is increased to 7.0%, while the rest are the same as in Example 1.

[0049] Comparative Example 4 This comparative example provides a cleaning agent for semiconductor packaging, which differs from Example 1 in that: EDTA-2Na and HEDP are not added, and the amount of deionized water is increased to 61.45% accordingly; otherwise, it is the same as Example 1.

[0050] Comparative Example 5 This comparative example provides a cleaning agent for semiconductor packaging, which differs from Example 1 in that: benzotriazole is not added, and the amount of deionized water is increased to 60.05% accordingly; all other aspects are the same as in Example 1.

[0051] Comparative Example 6 This comparative example provides a cleaning agent for semiconductor packaging, which differs from Example 1 in that sodium citrate is not added and the amount of citric acid is increased to 0.45%, while the rest is the same as Example 1.

[0052] Comparative Example 7 This comparative example provides a cleaning agent for semiconductor packaging. The difference from Example 1 is that the total amount of alcohol ether solvent A (propylene glycol methyl ether + dipropylene glycol methyl ether) remains unchanged at 23.0%, the amount of dipropylene glycol butyl ether is increased to 12.5%, and the amount of deionized water is adjusted accordingly to 55.45%. All other aspects are the same as in Example 1.

[0053] Comparative Example 8 This comparative example provides a cleaning agent for semiconductor packaging. The difference from Example 1 is that the total amount of alcohol ether solvent A (propylene glycol methyl ether + dipropylene glycol methyl ether) remains unchanged at 23.0%, the amount of dipropylene glycol butyl ether is reduced to 4.6%, and the amount of deionized water is adjusted accordingly to 63.35%. All other aspects are the same as in Example 1.

[0054] The physicochemical properties of the semiconductor packaging cleaning agents prepared in the above embodiments and comparative examples were tested using the following methods: (1) Dynamic foam performance test: 10 L of cleaning agent concentrate was injected into the spray cleaning tank and sprayed continuously for 10 min at 0.3 MPa and 45℃. The stable height of the foam layer (mm) was measured. After the spraying was stopped, the time required for the foam to completely disappear (s) was recorded.

[0055] (2) Material compatibility test (metal corrosion rate): Prepare copper, aluminum, and nickel metal test pieces (50 mm × 25 mm × 1 mm), weigh them accurately, and place them in a continuous circulating spray device. Spray them at 0.2 MPa and 45℃ for 72 hours, replenishing with deionized water daily to maintain the liquid level. After the test, remove the test pieces, clean and dry them, weigh them, and calculate the corrosion rate (mg / (cm³)). 2 ·h)).

[0056] (3) pH stability test: Take the cleaning agent stock solution and run it in continuous circulating spray (45℃, 0.2 MPa) for 72 h. Take samples every 8 h, cool to 25℃ and measure the pH value. Record the initial pH value and the final pH value.

[0057] The results of various performance tests are shown in Tables 1 and 2.

[0058] Table 1: Dynamic foam performance and pH stability

[0059] Table 2: Material Compatibility

[0060] As shown in Table 1, the cleaning agent of the present invention exhibits low foam height and rapid defoaming under spraying conditions, and its pH remains stable after prolonged cyclic spraying, indicating that the cleaning agent possesses excellent low-foaming characteristics and buffering capacity. While some comparative examples are similar to the examples in foaming performance, they exhibit serious deficiencies in other key indicators. Furthermore, comparative examples that omit alcohol ether solvent B, omit any surfactant, or use only citric acid without sodium citrate show significantly increased foam height, prolonged defoaming time, or severe pH drift. This demonstrates that the presence of alcohol ether solvent B, the combination of the two surfactants, and the citric acid / sodium citrate buffer pair in the present invention are crucial for simultaneously achieving low foaming and high pH stability.

[0061] As shown in Table 2, the corrosion rates of the three sensitive metals, copper, aluminum, and nickel, in the embodiments of the present invention are all at extremely low levels, demonstrating excellent material compatibility. The comparative examples, which omit the copper corrosion inhibitor or use only citric acid without sodium citrate, show a significantly increased corrosion rate, indicating that the synergistic use of benzotriazole and the citric acid / sodium citrate buffer system is necessary to inhibit metal corrosion.

[0062] The semiconductor packaging cleaning agents prepared in the above embodiments and comparative examples were used in a spray cleaning process to remove flux residues from the surface of semiconductor packaged devices. This was used to evaluate the cleaning effect and reliability of the cleaning agents on the device surface in a practical cleaning process. Before use, the cleaning agent can be diluted with deionized water (undiluted or diluted 1:5 to 1:20) according to the amount of residue on the device surface. The cleaning temperature is 40 to 50°C, the spray pressure is 0.2 to 0.4 MPa, and the cleaning time is 3 to 10 minutes. After cleaning, the device should be thoroughly rinsed with deionized water. The test method is as follows: (1) Cleaning rate test (IPC weighing method): Lead-free, no-clean flux was uniformly applied to the PCB board (5 cm × 5 cm), with a coating amount of approximately 0.2 g. After reflow soldering, the board was weighed. The board was cleaned at 45℃ and 0.3 MPa spray pressure for 5 min, then rinsed three times with deionized water, dried, and weighed. The cleaning rate was calculated using the formula: (Weight of the board before cleaning - Weight of the board after cleaning) / Flux coating amount × 100%.

[0063] (2) Ionic contaminant (NaCl equivalent) test: Using an Omega Meter 600 SMD instrument, the total amount of ionic contaminants on the PCB board surface after cleaning was tested, expressed as NaCl equivalent (μg / cm³). 2 )express.

[0064] (3) Halogen ions (Cl) - ,Br - Test: Ion chromatography (Dionex ICS-5000 ion chromatograph) was used. After cleaning, the PCB board was used to extract surface ions with 10 mL of deionized water. The extract was filtered through a 0.22 μm filter before injection analysis. Note: Cl - The detection limit is 0.02 ppm, Br - The detection limit is 0.05 ppm.

[0065] (4) Non-volatile residue (NVR) test: The cleaned PCB board was placed in a desiccator and dried at room temperature for 24 h, and then weighed. The residue on the board surface was then extracted using isopropanol ultrasonically. After the extract was evaporated to dryness, the residue was weighed, and the amount of non-volatile residue per unit area (μg / cm²) was calculated. 2 ).

[0066] (5) High Temperature and High Humidity Reverse Bias Test (H3TRB): Using an IPC-B-25 comb electrode test board, after cleaning, it is placed in an 85℃ / 85% RH constant temperature and humidity chamber, with a +50 V bias voltage applied for 1000 h. The surface insulation resistance (SIR) is measured every 168 h, and the SIR value is required to always be ≥1×10 8 Ω indicates compliance. Record the SIR value at 1000 h and whether it passes the test.

[0067] The results of various performance tests are as follows Figure 2 As shown in Tables 3 and 4.

[0068] Table 3: Cleaning efficiency, ionic residues, and non-volatile residues

[0069] Table 4: Reliability Testing

[0070] Depend on Figure 2 As shown in Table 3, the cleaning effect of the embodiments of the present invention on flux residue is significantly better than that of the comparative examples. After cleaning, the total ion residue, halide ion, and non-volatile residue on the device surface are all at extremely low levels. Omitting alcohol ether solvent B, omitting any surfactant, omitting the chelating agent, or deviating from the specific ratio range of alcohol ether solvents A and B all lead to a decrease in cleaning rate or an increase in residue. This confirms the necessity of the synergistic effect of alcohol ether solvents A and B within a specific ratio range, the combination of the two surfactants, and the combination of chelating agents for achieving efficient cleaning and ultra-low residue.

[0071] As shown in Table 4, the devices cleaned in the embodiments of the present invention all passed the high temperature and high humidity reverse bias test, and their surface insulation resistance remained above the qualified level throughout. Most comparative examples showed a drop in surface insulation resistance to the unqualified level or premature failure during the test. A few comparative examples, although passing the test, had excessively high corrosion rates, failing to meet long-term reliability requirements. This indicates that only under the combined constraints of the components and their proportions in the present invention can the cleaned devices maintain long-term reliability in harsh high temperature and high humidity biased environments.

[0072] In summary, this invention does not pursue the optimization of a single performance characteristic, but rather achieves excellent performance in five aspects simultaneously: low foaming performance, cleaning efficiency, material compatibility, ultra-low residue, and high reliability through the combined action of the critical synergistic ratio of alcohol ether solvents A and B, the optimized compounding of the two surfactants, the compounding chelating agent, buffer pairs, and corrosion inhibitors. While some comparative examples may be close to this invention in certain performance aspects, they have significant deficiencies in other key areas and cannot meet the comprehensive requirements for high-reliability semiconductor packaging cleaning.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A cleaning agent for semiconductor packaging, characterized in that, It consists of the following components by mass percentage: alcohol ether solvent A 18~28%, alcohol ether solvent B 6~12%, low-foaming nonionic surfactant 3~6%, isomeric alcohol ether surfactant 2.5~5%, chelating agent 0.8~2.5%, copper corrosion inhibitor 0.08~0.2%, pH adjuster 0.2~0.8%, and the balance is deionized water.

2. The semiconductor packaging cleaning agent according to claim 1, characterized in that: Alcohol ether solvent A is propylene glycol methyl ether and / or dipropylene glycol methyl ether; alcohol ether solvent B is one or more of dipropylene glycol butyl ether, propylene glycol butyl ether, and diethylene glycol butyl ether; the mass ratio of alcohol ether solvent A to alcohol ether solvent B is 2.5:1 to 4:

1.

3. The semiconductor packaging cleaning agent according to claim 2, characterized in that: Alcohol ether solvent A is a compound of propylene glycol methyl ether and dipropylene glycol methyl ether in a mass ratio of 2:1 to 5:1; alcohol ether solvent B is dipropylene glycol butyl ether.

4. The semiconductor packaging cleaning agent according to claim 1, characterized in that: The low-foaming nonionic surfactant has the structural formula R-O-(CH2CH2O) n -H, wherein R is a C8-C10 linear or branched alkyl group, n = 3-5, and the HLB value is 7-10.

5. The semiconductor packaging cleaning agent according to claim 1, characterized in that: The structural formula of the isomeric alcohol ether surfactant is R'-0-(CH2CH20) m -H, wherein R' is a branched C10-C13 alkyl group, the degree of branching of the branched alkyl group is > 60%, m = 5-8, and the HLB value is 12-14.

6. The semiconductor packaging cleaning agent according to claim 1, characterized in that: The chelating agent is a compound of disodium ethylenediaminetetraacetate and hydroxyethylidene diphosphonic acid in a mass ratio of 1:1 to 3:

1.

7. The semiconductor packaging cleaning agent according to claim 1, characterized in that: The copper corrosion inhibitor is benzotriazole.

8. The semiconductor packaging cleaning agent according to claim 1, characterized in that: The pH adjuster is a buffer pair of citric acid and sodium citrate with a mass ratio of 1:1.5 to 1:2.

5.

9. A method for preparing a semiconductor packaging cleaning agent as described in any one of claims 1-8, characterized in that, Includes the following steps: S1. Add 30% to 50% of the total amount of deionized water to the reactor and heat it to 25 to 45°C. S2. While stirring at 200-400 rpm, add alcohol ether solvent A, alcohol ether solvent B, low-foaming nonionic surfactant, and isomeric alcohol ether surfactant to the reactor in sequence, stirring for 3-5 minutes after each addition. S3. Under stirring conditions, add chelating agent and copper corrosion inhibitor to the reactor and continue stirring for 5-10 minutes. S4. Under stirring conditions, add pH adjuster to the reactor and stir until homogeneous; S5. While stirring at 300-500 rpm, add the remaining deionized water at a rate of 50-200 g / min, controlling the system temperature to not exceed 50℃. After the addition is complete, continue stirring for 15-30 minutes until the solution is transparent and homogeneous. S6. Let stand for 10-20 minutes to defoam, then filter through a 0.45μm filter to obtain the semiconductor packaging cleaning agent.

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