Chip encapsulant overflow softener

Abstract

The application discloses a chip plastic sealing material overflow softener, and mainly comprises the following components: alcohol amine organic base, amide and azomethine pyrrolidone solvent, alcohol amine ether solvent, and dihydric alcohol ether acetate wax removing agent. The application has the double functions of softening and removing the overflow epoxy resin under low temperature conditions, and dissolving the overflowed paraffin or polyethylene wax in the epoxy resin plastic sealing material under the low temperature condition of 60 DEG C+ / -10 DEG C.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of overflow of plastic sealing material processing technology. BACKGROUND

[0002] Chip plastic sealing material is usually composed of epoxy resin. The chemical softening of existing chip plastic sealing material is a high-temperature process above 100℃. Since the working temperature is high, it has a great adverse effect on the performance of the encapsulated plastic sealing material and the encapsulated chip product. However, the softening temperature of the solventing agent of epoxy resin plastic sealing material, paraffin wax and polyethylene wax, is very high. The softening point of paraffin wax is 86℃, and the softening point of polyethylene wax is 115℃. It is difficult to remove it at a temperature lower than the softening point of the wax.

[0003] The invention with application number 201810202983.5 discloses a softener for softening liquid crystal box frame glue, which comprises 5% to 10% by volume of ethanol, 10% to 20% by volume of ethyl acetate and 70% to 85% by volume of trichloromethane. The softener can quickly and effectively soften the cured epoxy resin glue, but cannot remove the wax.

[0004] The invention with application number 201910499086.X discloses a concentrated wax removal water for easy wax separation and a preparation method thereof, relating to the field of metal detergents. The technical key points are as follows: a concentrated wax removal water for easy wax separation, comprising the following components in parts by weight: 1 to 3 parts of modified MOFs; 7.5 to 8 parts of nonylphenol polyoxyethylene ether; 15 to 16 parts of coconut oil fatty acid diethanolamide; 2.5 to 3 parts of glycerol; 0.5 to 1 part of polyethylene glycol; 9 to 10 parts of diethylene triamine; and 40 to 50 parts of anhydrous ethanol. The invention cannot soften epoxy resin.

[0005] The paper "44 Epoxy Resin Glycol Amine Water-based Research" published in Zhejiang Chemical Industry, Vol. 49, No. 2, 2018, uses diethanolamine to modify 44 epoxy resin to prepare a series of water-based epoxy resins, studies the effects of modifier dosage, reaction temperature and time on the stability of water-based epoxy resin, and establishes the best raw material ratio and reaction conditions. The results show that when the amount of diethanolamine increases, the hydrophilicity of the modified epoxy resin increases, the particle size of the water-based epoxy resin decreases, and the curing performance deteriorates. It shows that diethanolamine has some effect on epoxy resin.

[0006] Formamide is a colorless transparent liquid with active reactivity and special solubility. It can be used as a paper treatment agent, a softener for fiber industry, a softener for animal glue, and an excellent organic solvent. Formamide is a compound formed by replacing the hydroxyl group in acetamide and acetic acid with an amino group. It has weak basicity and is widely used as a solvent for organic and inorganic substances and an antacid.

[0007] N-methylpyrrolidone, colorless transparent oily liquid, slightly amine odor. With water, alcohol, ether, ester, ketone, halogenated hydrocarbon, aromatic hydrocarbon mutual solubility, is a good extraction solvent, widely used in aromatic extraction, acetylene concentration, butadiene separation and synthesis gas desulfurization process as an extractant, but also in the production of pesticides, engineering plastics, coatings, synthetic fibers, integrated circuits, etc. Solvent. SUMMARY

[0008] OBJECTIVE

[0009] The application provides a chip plastic sealing material overflow softening agent which can soften the overflow (flash) of the epoxy resin at a lower temperature and remove the high softening point wax at the same time, and meets the requirements of the packaging process.

[0010] TECHNICAL SCHEME

[0011] The softening agent of the application is used for softening the overflow of the semiconductor epoxy resin plastic sealing product of the copper frame, the iron-nickel alloy frame, the copper surface nickel-palladium-gold plated frame and the iron-nickel alloy nickel-palladium-gold plated frame after the plastic sealing is completed, and dissolving the overflowed carnauba wax or polyethylene wax, so as to facilitate the subsequent electroplating process of the frame.

[0012] In order to achieve the above-mentioned purpose, the alcohol amine organic base is used, including ethanolamine, diethanolamine, triethanolamine, dimethyl ethanolamine, isopropanolamine, diisopropanolamine, triisopropanolamine, and the organic base can penetrate into the solidified epoxy resin structure under the condition of heating, so that the epoxy resin is swelled and softened, and then it is removed by mechanical external force. However, if the organic base is too much and too strong, it will damage the plastic sealing body outside the overflow, so the amide including dimethylformamide, dimethylacetamide, dimethylpropionamide or azomethyl pyrrolidone solvent is matched to achieve moderate effect. The alcohol amine substance accounts for 30% to 50% of the total weight, the solvent accounts for 40% to 60% of the total weight, or other additives (such as dispersants, other solvents, cosolvents, etc.) make up 100%. The effect is obvious under the condition of high temperature above 100 DEG C, and the effect is not good under the condition of lower temperature of about 60 DEG C.

[0013] Therefore, in view of the above low-temperature effect, the alcohol amine ether type solvent (hydrogen atoms or oxygen atoms, nitrogen atoms in the alcohol amine ether type molecules can form hydrogen bonds or coordination bonds with oxygen atoms or hydrogen atoms in the epoxy groups of the epoxy resin, which is helpful for the softening, dissolution and peeling of the epoxy resin overflow; however, there is no excessive chemical reaction between the polar groups of the inorganic base and the epoxy resin) is added, including ethanol amine ether, diethanol amine ether, triethanol amine ether, dimethyl ethanol amine ether, isopropanol amine ether, diisopropanol amine ether, triisopropanol amine ether, under the action of the above-mentioned substances, the overflow of the epoxy resin plastic package material is softened at a relatively low temperature of 60-70°C, and the epoxy resin plastic package body is not damaged, so that the performance of the product is not destroyed, and the reliability of the product is ensured. Moreover, the alcohol amine and the alcohol amine ether substance have basically the same or similar functional groups, are similar and compatible, do not produce exclusion phenomenon or side reaction, and preferably the alcohol amine and the alcohol amine ether substance with the same group are used, such as ethanol amine and ethanol amine ether, or diethanol amine and diethanol amine ether, or dimethyl ethanol amine and dimethyl ethanol amine ether.

[0014] In order to solve the problem of the high melting point (70-120°C) of the paraffin wax or polyethylene wax in the overflow of the plastic package material, the binary alcohol ether acetate substance is added, and the above-mentioned solvent is used, so that the paraffin wax and the polyethylene wax are cleaned at a low temperature of about 60°C±10°C, and the plating leakage phenomenon does not occur in the subsequent plating process. The alcohol amine substance accounts for 15%-25% of the total weight, the alcohol amine ether accounts for 20%-30% of the total weight, the solvent accounts for 25%-35% of the total weight, and the binary alcohol ether acetate accounts for 20%-30% of the total weight.

[0015] Because of the strong hydrogen bond association ability between amide molecules, liquid amide not only can dissolve organic compounds, but also can dissolve many inorganic compounds, and is a good solvent. Especially N,N-dimethylformamide and N,N-dimethylacetamide can be mixed with water and most organic solvents and many inorganic liquids in any proportion, and are very good aprotic polar solvents; they have similar compatible structures with nitrogen methyl pyrrolidone, and the combination of the two types of solvents can further increase the solubility, complement the functions, and reduce the softening temperature. Amide molecules can form hydrogen bonds with alcohol amine or alcohol amine ether, and have strong association ability, accounting for about 2 / 3; nitrogen methyl pyrrolidone has a high cost, accounting for about 1 / 3 of the solvent.

[0016] In the present application, further preferably, the main components of the softening agent: dimethyl ethanolamine, dimethyl ethanolamine ether, N, N-dimethyl acetamide, N-methyl pyrrolidone solvent, ethylene glycol ether acetate, have the common group dimethyl or ethyl, completely without side reaction; and also has the following advantages: better mutual solubility, further improving the softening and wax removal effect; the cost of these raw materials is low, the melting point is low, it is liquid at room temperature, and it is not easy to volatilize at the soaking temperature; therefore, the soaking temperature required for treating the overflow of the epoxy resin plastic package can be as low as 50 DEG C.

[0017] The matching chip epoxy resin plastic package mass production process is as follows:

[0018] The softening agent of the present application is soaked and softened, high-pressure water is struck (mechanically), and electroplating treatment is performed.

[0019] The softening soaking conditions are: temperature 70 DEG C + / - 10 DEG C, time 60 min + / - 10 min; then high-pressure water is struck and washed at 40 DEG to 60 DEG, 250 to 400 Kg, and electroplating treatment liquid treatment is performed.

[0020] Beneficial effects:

[0021] The present application is a kind of chemical softening agent, which is a kind of chemical product that has a softening effect on the overflow of epoxy resin plastic package generated in the injection molding process of semiconductor integrated circuit packaging production. It has a softening effect on the overflow of epoxy resin at low temperature conditions, achieving the effect of removing the overflow, but compared with similar softening agents, its big highlight is that it can also dissolve the paraffin and polyethylene wax in the overflowed epoxy resin plastic package at low temperature conditions.

[0022] The low temperature condition of 60 DEG C + / - 10 DEG C of the present application meets the chemical softening requirement of not damaging the product plastic package, and the low process temperature also ensures that the performance of the product is not damaged, ensuring the reliability of the product.

[0023] As the effective components, it contains: alcohol amine, amine ether, amide, N-methyl pyrrolidone, and dihydric alcohol ether acetate substances. These components do not belong to the category of environmental harmful substances controlled, and are environmentally friendly softening agents. DETAILED DESCRIPTION

[0024] Dosage example:

[0025] The experimental sample No. 1 is an example of the present application, which takes ethanolamine 20 g as an alcohol amine substance, takes ethanolamine ether 25 g as an alcohol amine ether substance, takes dimethyl acetamide 20 g as an amide substance, takes N-methyl pyrrolidone 10 g as an N-methyl pyrrolidone substance, and takes ethylene glycol ether acetate 25 g as a dihydric alcohol ether acetate substance, and is configured into a mixed solution.

[0026] Experimental sample No. 2 is a comparative example not containing dihydric alcohol ether acetate, 20 g of ethanolamine is taken as an alcohol amine substance, 25 g of ethanolamine ether is taken as an alcohol amine ether substance, 20 g of dimethylacetamide is taken as an amide substance, and 10 g of N-methyl pyrrolidone is taken as a nitrogen methyl pyrrolidone substance, and a mixed solution is prepared.

[0027] Experimental sample No. 3 is a comparative example not containing an alcohol amine substance, 25 g of ethanolamine ether is taken as an alcohol amine ether substance, 20 g of dimethylacetamide is taken as an amide substance, 10 g of N-methyl pyrrolidone is taken as a nitrogen methyl pyrrolidone substance, and 25 g of ethylene glycol ether acetate is taken as a dihydric alcohol ether acetate substance, and a mixed solution is prepared.

[0028] Experimental sample No. 4 is a comparative example using an inorganic base, 20 g of 30% potassium hydroxide solution is taken, 20 g of dimethylacetamide is taken as an amide substance, 10 g of N-methyl pyrrolidone is taken as a nitrogen methyl pyrrolidone substance, and 25 g of ethylene glycol ether acetate is taken as a dihydric alcohol ether acetate substance, and a mixed solution is prepared.

[0029] Example 1:

[0030] A TO-220 experimental wafer (epoxy resin plastic encapsulated chip connected to a copper lead frame) is used for testing, and the experimental conditions are set to be immersed at 65°C for 30 minutes, and the experimental results are shown in the following table.

[0031] .

[0032] According to the results in the above table, it is shown that the alcohol amine substance has a relatively obvious effect on softening overflow, and the dihydric alcohol ether acetate substance has a better dissolving effect on wax.

[0033] Example 2:

[0034] A mixture of 3 g of beeswax and 3 g of polyethylene wax in a ratio of 1:1 is taken, and is placed in 10 g of experimental sample, and is immersed at 70°C for half an hour, and the dissolving condition of the wax is investigated separately. The experimental results are shown in the following table.

[0035] .

[0036] Through this example, the dissolving capacity of each experimental sample on the wax can be directly observed.

[0037] Example 3:

[0038] A TO-220 product is used for testing, and the experimental conditions are set to be immersed at 70°C for 30 minutes and 60 minutes, and then reliability testing is performed

[0039] .

[0040] Referring to the results of the above table, the 1, 2, 3 sample using an alcohol amine organic base as the basic component has better reliability of the plastic package body than the 4 sample of the inorganic base type

[0041] Test conclusion:

[0042] As can be seen from the above examples 1, 2, 3, at a temperature of 60-70℃:

[0043] The 1, 2, 4 samples have good overflow softening effect, the 2 sample has poor wax removal effect, and the 3 sample has poor softening effect. The 1, 3, 4 samples using dihydric alcohol ether acetate solvents have good wax removal effect and no plating leakage phenomenon, which is better than the 2 sample without dihydric alcohol ether acetate solvents. This shows that the dihydric alcohol ether acetate substances have good dissolving effect on wax. The 1, 2, 3 samples have no adverse result of layering of the plastic package body, and the 4 sample has layering effect on the quality of the plastic package body.

[0044] The softening agent of the present application has a softening effect on the overflow of the epoxy resin, can achieve mechanical removal (such as high-pressure water striking) of the overflow, has the function of dissolving the wax-like substances such as paraffin wax or polyethylene wax on the surface of the plastic package material, and is convenient for subsequent electroplating treatment of the lead frame of the plastic package body.

Claims

1. A chip molding compound overflow softener, characterized in that: The main components of the softener include: alcohol amine organic base, solvent, alcohol amine ether antifreeze, glycol ether acetate wax remover; The alcohol amine organic base accounts for 15-25% of the total weight, the solvent accounts for 25-35% of the total weight, the alcohol amine ether antifreeze accounts for 20-30% of the total weight, and the glycol ether acetate wax remover accounts for 20-30% of the total weight; The solvent is an amide solvent and a nitrogen methyl pyrrolidone solvent, wherein the amide solvent is dimethylformamide, dimethylacetamide or dimethylpropionamide; The alcohol amine ether antifreeze is one or more of ethanol amine ether, diethanol amine ether, triethanol amine ether, dimethyl ethanol amine ether, isopropanol amine ether, diisopropanol amine ether and triisopropanol amine ether; The glycol ether acetate wax remover is one or more of ethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, diethylene glycol methyl ether acetate, diethylene glycol ethyl ether acetate, dipropylene glycol methyl ether acetate ether; The softener with the above four components is used for soaking treatment at 60-70 DEG C, which can soften the overflow of the epoxy resin plastic sealing material of the chip, and then the overflow is removed by mechanical method.

2. The encapsulant flash softener of claim 1, wherein: The softener is used for soaking treatment at 60-65 DEG C, and the overflowed carnauba wax or polyethylene wax in the plastic sealing material is cleaned.

3. The encapsulant flash softener of claim 1 or 2, wherein: The amide solvent is N,N-dimethylacetamide, which accounts for 2 / 3 of the solvent; the nitrogen methyl pyrrolidone solvent accounts for 1 / 3 of the solvent.