A mold cleaning sponge for semiconductor packaging mold and a mold cleaning composition and use method thereof

Abstract

The present invention relates to a mold cleaning sponge for semiconductor packaging molds and a mold cleaning composition and a method for using the same. The structure of the sponge from top to bottom comprises: a first outer layer, a first transport layer, a water storage layer, a second transport layer, and a second outer layer; the layers are fixedly connected; the sponge has a density of 30-60 kg / m 3 By adjusting the melamine sponge's formula design and foaming process, the curing degree of the melamine sponge is effectively controlled, resulting in a melamine sponge with more active groups, which effectively improves the mold cleaning effect through interfacial reaction. The sponge is designed to have a structure from top to bottom consisting of: a first outer layer, a first transport layer, a water storage layer, a second transport layer, and a second outer layer; the layers are fixedly connected, and the sponge is set with gradient changes in curing degree, density, average pore size, and micro-nano structure. This can improve the sponge's storage performance and the efficiency of cleaning the upper and lower molds.

Description

Technical Field

[0001] The present invention relates to the technical field of mold cleaning compositions, and more particularly to a mold cleaning sponge for semiconductor packaging molds, a mold cleaning composition, and a method for using the same. Background Art

[0002] In the electronic packaging industry, when using epoxy resin molding compound to realize chip packaging, after the epoxy molding compound repeats the packaging operation for hundreds of times, the surface of the mold is easily attached with residues produced by epoxy resin curing, causing varying degrees of pollution to the surface of the packaging mold. Therefore, studying efficient cleaning methods for metal molds has always been an important task in the packaging process. The mold cleaning methods currently developed are mainly divided into two categories: in-situ cleaning and off-line cleaning. Because the former is far superior to the latter in terms of ease of operation, and the mold cleaning effect can also meet the mold cleaning requirements, it is widely used in the industry. In the in-situ cleaning method, existing mold cleaning products can be divided into solid and liquid types. Solid products mainly include mold cleaning rubber and melamine mold cleaning resin.

[0003] Sponges are a common material in everyday life, known for their excellent water absorption, resilience, fine, high-density internal structure, and modifiable molecular structure. However, they have not been used in semiconductor packaging mold cleaning applications. Polyurethane sponges and melamine sponges share these characteristics and can be used within the operating temperature range of semiconductor packaging molds. Melamine sponges are hard, flame-retardant, and have a nanoscale, three-dimensional mesh-like open-pore structure, making them suitable for daily cleaning, flame retardant materials, and sound-absorbing cotton, respectively. In addition to their physical properties, some melamine sponges are also used for oil-water separation through hydrophobic modification. Polyurethane sponges are also used in mattresses and cushioning materials due to their elastic properties. However, after absorbing liquids, sponges inevitably have a drawback when storing them for long periods of time: they cannot effectively distribute the fluid against gravity.

[0004] CN109776852B discloses a composite sponge comprising a polyurethane sponge and a polyvinyl alcohol sponge bonded within the polyurethane sponge's lattice-like spaces. The composite sponge combines the roughness of the polyurethane sponge with the high water absorption and water retention of the polyvinyl alcohol sponge. After the polyurethane sponge separates dirt from the surface of the object being wiped, the polyvinyl alcohol sponge absorbs water and dirt from the surface, making it particularly suitable for cleaning floors.

[0005] CN112266455B adds highly absorbent resin or fluff pulp fibers to the sponge formula. The fluff pulp itself has a fast absorption effect and a strong conductive effect on liquids, which can quickly distribute fluids, solving the problem that polyurethane sponge absorbers cannot effectively overcome gravity to distribute fluids due to large pores.

[0006] Although there have been many attempts to improve the water retention of sponges, there is still no sponge that can simultaneously meet the requirements of high water retention and simple molding processability due to the complex preparation process of the adsorbed solution or the sponge modification method. Summary of the Invention

[0007] The first aspect of the present invention provides a mold cleaning sponge for semiconductor packaging molds. The structure of the sponge from top to bottom includes: a first outer layer, a first transport layer, a water storage layer, a second transport layer, and a second outer layer; the layers are fixedly connected; the sponge has a density of 30-60 kg / m 3 melamine sponge.

[0008] Preferably, the sponge has a density of 30-55 kg / m 3 melamine sponge.

[0009] Preferably, the interlayer fixing method is gluing, and the gluing areas are at the four corners.

[0010] The melamine sponge of the first outer layer and the second outer layer has a curing degree of 60-80%, an average pore size of 400-600 μm, and a porosity of 50-70%; the melamine sponge of the water storage layer has a curing degree of 80-100%, an average pore size of 200-400 μm, and a porosity of 50-70%; the melamine sponge of the first transport layer and the second transport layer has a curing degree of 80-100%, an average pore size of 50-200 μm, and a porosity of 50-70%.

[0011] Preferably, the curing degree of the melamine sponge of the first outer layer and the second outer layer is 60-70%, the curing degree of the melamine sponge of the water storage layer is 80-90%, and the curing degree of the melamine sponge of the first transport layer and the second transport layer is 80-90%.

[0012] The research of this application found that by designing the structure of the sponge from top to bottom to include: a first outer layer, a first transport layer, a water storage layer, a second transport layer, and a second outer layer; the layers are fixedly connected and a sponge with gradient-varying curing degree, density, average pore size, and micro-nano structure is set, which can improve the storage performance of the sponge and the effect of efficiently cleaning the upper and lower molds. On the one hand, because the liquid can be transported unpowered through the transport layer and the water storage layer in conjunction with the outer layer, overcoming the effect of gravity, the mixed solution can form intermolecular hydrogen bonds inside the sponge, forming a "target" for the liquid, "hanging" the liquid, and improving the storage stability of the liquid. On the other hand, when cleaning the mold at high temperature, the liquid can be squeezed to achieve uniform distribution within the gradient-distributed sponge pore size, while cleaning the upper and lower molds of the mold.

[0013] The degree of curing is compared with that of a fully cured melamine sponge (Zhengzhou Fengtai Nanomaterial Co., Ltd., with an elastic modulus of 5 MPa and a sponge density of 16 kg / m 3 ), the compressive strength and elastic modulus of the sponge obtained by designing different curing parameters are obtained to obtain the corresponding curing degree (refer to the performance test section for details).

[0014] The raw materials for preparing the melamine sponge include, by weight, 100 parts of melamine formaldehyde resin, 6-12 parts of emulsifier, 6-10 parts of foaming agent, 5-10 parts of pore opening agent, and 10-20 parts of curing agent.

[0015] Preferably, the raw materials for preparing the melamine sponge include, by weight: 100 parts of melamine formaldehyde resin, 8-10 parts of emulsifier, 6-8 parts of foaming agent, 5-7 parts of pore opening agent, and 12-18 parts of curing agent.

[0016] The emulsifier is at least one of sodium dodecylbenzene sulfonate, sodium lauryl sulfate, alkylphenol polyoxyethylene ether, polyoxyethylene alkyl ester, sodium cetyl betaine, and polyoxyethylene alkyl aryl ester.

[0017] Preferably, the emulsifier is at least one of sodium dodecylbenzenesulfonate and sodium dodecyl sulfate.

[0018] Preferably, the foaming agent is at least one of n-butane, n-pentane and n-hexane.

[0019] The pore opening agent is at least one of azobisisobutyronitrile, azobisisoheptanenitrile and azoisobutylcyanamide.

[0020] Preferably, the pore opening agent is at least one of azobisisobutyronitrile and azobisisoheptanenitrile.

[0021] Preferably, the curing agent is at least one of formic acid, acetic acid and a 37 wt % formaldehyde aqueous solution.

[0022] Further preferably, the curing agent is at least one of acetic acid and a 37 wt % formaldehyde aqueous solution.

[0023] The preparation steps of the melamine sponge include: taking melamine formaldehyde resin, adding emulsifier, stirring evenly, then adding foaming agent, pore opening agent and curing agent and mixing evenly; firstly performing microwave foaming, and then curing to set the shape.

[0024] The curing temperature is between 160-200° C., the pressure is between 3-5 MPa, and the curing time is between 20-40 minutes.

[0025] Preferably, the curing temperature is between 180-200° C., the pressure is between 3-4 MPa, and the curing time is between 20-40 min.

[0026] The second aspect of the present invention provides a mold cleaning composition, comprising a mold cleaning agent and a mold cleaning sponge.

[0027] The weight ratio of the mold cleaning sponge to the mold cleaning agent is 1: (36-45).

[0028] Calculated by weight percentage, the mold cleaning agent includes: 20-35 parts of a main cleaning agent, 3-10 parts of an alkaline cleaning auxiliary agent, 10-20 parts of a surfactant, 5-15 parts of a water-soluble polymer, and the balance is supplemented by deionized water.

[0029] The main cleaning agent includes at least one of ethanolamine, diethanolamine, triethanolamine, diethylenetriamine, hydroxyethylethylenediamine, methyl isobutyl ketone, ethyl isobutyl ketone, methyl ethyl ketone, acetone, butanone, cyclohexane, propylene oxide, methyl acetate, ethyl acetate, and propyl acetate.

[0030] The alkaline cleaning aid includes at least one of potassium hydroxide, sodium hydroxide, lithium hydroxide, calcium hydroxide, and barium hydroxide.

[0031] The surfactant includes at least one of stearic acid soap, fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, dodecyl diethanolamide, sodium oleate, sodium dodecylbenzene sulfonate, and sodium lauryl sulfate.

[0032] The water-soluble polymer includes at least one of starch, gum arabic, sodium alginate, bone meal, gelatin, casein, carboxymethyl cellulose, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, polyacrylamide, polyacrylic acid, polyvinyl pyrrolidone, polyvinyl alcohol, polymaleic anhydride, polyquaternary ammonium salt, and polyethylene glycol.

[0033] The water-soluble polymer includes carboxymethyl cellulose and polyacrylamide, and the mass ratio of the carboxymethyl cellulose to the polyacrylamide is (0.4-2):1.

[0034] The third aspect of the present invention provides a method for using the mold cleaning composition, which is used in conjunction with a mold cleaning strip, and specifically comprises the following steps:

[0035] S1, placing the mold cleaning composition on the surface of the mold to be cleaned for mold cleaning;

[0036] S2, cleaning by mold cleaning strips;

[0037] S3, repeat steps S1 and S2 1-3 times.

[0038] Preferably, the method specifically includes the following steps:

[0039] S1, placing the mold cleaning composition on the surface of the mold to be cleaned for mold cleaning;

[0040] S2, cleaning by mold cleaning strips;

[0041] S3, repeat steps S1 and S2 1-2 times.

[0042] The molding temperature is 150-190° C., the height compression rate of the mold cleaning sponge after molding is 50-90%, the molding time is 2-5 minutes, the molding time of the mold cleaning strip is 4-10 minutes, and the molding pressure of the mold cleaning sponge and the mold cleaning strip is 30-50 tonf.

[0043] Preferably, the molding temperature is 170° C., the height compression rate of the mold-clearing sponge after molding is 80%, the molding time is 3 minutes, the molding time of the mold-clearing rubber strip is 6 minutes, and the molding pressure is 40 tonf.

[0044] Beneficial effects:

[0045] 1. By adjusting the formula design and foaming process of melamine sponge, the curing degree of melamine sponge is effectively controlled, and more active groups (hydroxyl / amino groups) are obtained compared with the common melamine sponge on the market, which effectively improves the mold cleaning effect through interfacial reaction.

[0046] 2. The sponge is designed to have a structure from top to bottom that includes: a first outer layer, a first transport layer, a water storage layer, a second transport layer, and a second outer layer; the layers are fixedly connected, and the sponge is provided with gradient-varying curing degree, density, average pore size, and micro-nano structure, which can improve the sponge storage performance and the effect of efficiently cleaning the upper and lower molds.

[0047] 3. The specific mold cleaning composition of this application is used in combination with the mold cleaning strip, which not only improves the mold cleaning effect, but also reduces the number of mold cleaning times and improves production efficiency.

[0048] 4. The mold cleaning composition prepared in this application is safer and more environmentally friendly than mold cleaning spray.

[0049] 5. The water-soluble polymer includes carboxymethyl cellulose and polyacrylamide. The mass ratio of the carboxymethyl cellulose and polyacrylamide is (0.4-2):1, which can effectively improve the compatibility between the mold cleaning agent and the film cleaning sponge, maintain excellent total adsorption capacity and adsorption speed on the sponge, and thus improve the film cleaning efficiency and effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 Schematic diagram of the structure of the mold cleaning sponge in Example 1. 1. First outer layer; 2. First transport layer; 3. Water storage layer; 4. Second transport layer; 5. Second outer layer.

[0051] Figure 2 The infrared spectra of the sponge before and after mold cleaning in Example 3 are shown, wherein the red spectrum is after mold cleaning and the black spectrum is before mold cleaning.

[0052] Figure 3 Schematic diagram of sponge and glue coating in Example 1. DETAILED DESCRIPTION

[0053] Examples 1-11, Comparative Examples 1-3

[0054] A mold cleaning sponge for semiconductor packaging molds, such as Figure 1 As shown, the structure of the sponge from top to bottom is: first outer layer 1, first transport layer 2, water storage layer 3, second transport layer 4, second outer layer 5; the layers are fixedly connected; the interlayer fixing method is gluing, such as Figure 3 As shown, the adhesive areas are applied to the four corners (hatched areas).

[0055] The formula of the melamine sponge is shown in Table 1 in parts by weight; the emulsifier is sodium dodecylbenzenesulfonate; the foaming agent is n-butane; the pore opening agent is azobisisobutyronitrile; and the curing agent is a 37 wt % formaldehyde aqueous solution.

[0056] The preparation steps of the melamine sponge are as follows: taking melamine formaldehyde resin, adding an emulsifier, stirring evenly, then adding a foaming agent, a pore opening agent, and a curing agent and mixing evenly; first foaming in a microwave foaming oven at 100° C. for 1 minute, and then curing to set the shape (curing conditions are shown in Table 1).

[0057] Among them, in Example 1, the first outer layer 1 and the second outer layer 5 are made of melamine sponge prepared using formula 1 in Table 1; the water storage layer 3 is made of melamine sponge prepared using formula 2 in Table 1; and the first transport layer and the second transport layer 4 are made of melamine sponge prepared using formula 3 in Table 1.

[0058] Among them, in Example 2-11, the first outer layer 1 and the second outer layer 5 are made of melamine sponge prepared using formula 4 in Table 1; the water storage layer 3 is made of melamine sponge prepared using formula 4 in Table 1; and the first transport layer 2 and the second transport layer 4 are made of melamine sponge prepared using formula 4 in Table 1.

[0059] Among them, the mold cleaning sponge of Comparative Example 2-3 is a single-layer structure and is purchased from Zhengzhou Fengtai Nanomaterial Co., Ltd.

[0060] Table 1

[0061]

[0062] A mold cleaning composition comprises a mold cleaning agent and a mold cleaning sponge, the weight ratio of the two being shown in Table 4.

[0063] The formula of the mold clearing agent is shown in Table 2 by weight:

[0064] Table 2

[0065]

[0066] A method for using a mold cleaning composition, wherein Examples 1-11 and Comparative Examples 2-3 are used in combination with a mold cleaning strip, specifically comprising the following steps:

[0067] S1, placing the mold cleaning composition on the surface of the mold to be cleaned for mold cleaning;

[0068] S2, cleaning by mold cleaning strips;

[0069] S3, repeat steps S1 and S2 once.

[0070] The molding temperature is 170° C., the height compression rate of the mold-clearing sponge after molding is 80%, the molding time is 3 minutes, the molding time of the mold-clearing rubber strip is 6 minutes, and the molding pressure is 40 tonf.

[0071] Among them, Comparative Example 1 only uses the mold cleaning strips and does not use the mold cleaning sponge, and specifically includes the following steps: mold pressing and cleaning with the mold cleaning strips twice.

[0072] Performance testing methods and data

[0073] The melamine sponges of Example Formulas 1-3 were subjected to performance tests, and the test data are listed in Table 3.

[0074] Among them, compressive strength: GB / T 18944.1-2003 Polymer porous elastic materials sponges and porous rubber products (Part 1): Sheets.

[0075] Rebound rate: GB / T 6670-2008 Lightweight cellular polymeric materials - Determination of rebound properties by falling ball method.

[0076] Average pore size: GB / T 42269-2022 Test method for pore size of separation membranes, gas permeation method.

[0077] Apparent density: GB / T 6343-2009 Determination of apparent density of cellular plastics and rubber.

[0078] Porosity: T / CSTM 00553-2022 Method for Determination of Porosity of Lightweight Porous Materials.

[0079] The degree of curing was determined to be 100% when the rebound rate of the completely cured melamine sponge (Zhengzhou Fengtai Nanomaterial Co., Ltd.) was 70% (the elastic modulus was assumed to be proportional to the degree of curing), and the degree of curing of the melamine sponge of formula 1-3 was obtained.

[0080] The hydrophilic properties, storage properties, and mold cleaning performance of the sponges used in the examples and comparative examples were tested. The mold cleaning performance was rated as excellent, good, fair, or poor based on the following criteria: Excellent (95% or greater of the mold stain area removed); Good (70% to 95% of the mold stain area removed); Fair (70% to 30% or less of the mold stain area removed); and Poor (30% or less of the mold stain area removed). The test results are shown in Table 4.

[0081] Take the sponge after cleaning the mold in Example 3 and perform infrared analysis. Take the part of the interface between the sponge and the mold, as shown in Figure 3. Figure 2 As shown in the infrared spectrum, amino and hydroxyl groups (3500-3100 cm -1 ) The peaks that appeared changed significantly: before the experiment, the sponge was at about 3400 cm -1 and 3300cm -1 There is a double peak of primary amine at 3400 cm-1 after the experiment. -1 The peak disappears, only 3300cm -1 A single peak at , indicating that the primary amine becomes a secondary amine and a chemical reaction occurs, that is, the active groups on the sponge surface participate in the reaction of the mold containing epoxy groups.

[0082] Table 3

[0083]

[0084] Table 4

[0085]

[0086] From the results in Table 4, it can be seen that when only mold cleaning strips are used without mold cleaning sponges, the mold cleaning effect is average (good). When a single layer of mold cleaning sponge is used, the mold cleaning effect is also average (good) and the storage effect is poor. By compounding a specific water-soluble polymer carboxymethyl cellulose and polyacrylamide, the matching between the mold cleaning agent and the mold cleaning sponge can be effectively improved, and the excellent total adsorption capacity and adsorption speed of the sponge can be maintained, thereby improving the efficiency and effect of mold cleaning.

Claims

1. A mold cleaning composition, a mold cleaning sponge for semiconductor packaging molds, characterized in that: Including mold cleaning sponge and mold cleaning agent; The structure of the mold cleaning sponge from top to bottom includes: a first outer layer (1), a first transport layer (2), a water storage layer (3), a second transport layer (4), and a second outer layer (5); the layers are fixedly connected; the sponge has a density of 30-60 kg / m 3 Melamine sponge; The curing degree of the melamine sponge of the first outer layer (1) and the second outer layer (5) is 60-80%, and the average pore size is 400-600 μm; the curing degree of the melamine sponge of the water storage layer (3) is 80-100%, and the average pore size is 200-400 μm; the curing degree of the melamine sponge of the first transport layer (2) and the second transport layer (4) is 80-100%, and the average pore size is 50-200 μm; The mold clearing agent includes a water-soluble polymer, the water-soluble polymer includes carboxymethyl cellulose and polyacrylamide, and the mass ratio of the carboxymethyl cellulose to the polyacrylamide is (0.4-2):1; The raw materials for preparing the melamine sponge include: 100 parts of melamine formaldehyde resin, 6-12 parts of emulsifier, 6-10 parts of foaming agent, 5-10 parts of pore opening agent, and 10-20 parts of curing agent; The preparation steps of the melamine sponge include: taking melamine formaldehyde resin, adding emulsifier, stirring evenly, then adding foaming agent, pore opening agent, and curing agent and mixing evenly; first performing microwave foaming, and then curing to set the shape; The curing temperature is 160-200°C, the pressure is 3-5MPa, and the time is 20-40min; The weight ratio of the mold cleaning sponge to the mold cleaning agent is 1: (36-45).

2. A method for using the mold cleaning composition according to claim 1, characterized in that: Used in conjunction with mold cleaning strips, the specific steps include: S1, placing the mold cleaning composition on the surface of the mold to be cleaned for mold cleaning; S2, cleaning by mold cleaning strips; S3, repeat steps S1 and S2 1-3 times.

Images