Method for Removing Residual Adhesive after Cutting DFN or QFN Packages

Abstract

The present invention relates to a method for removing residual glue after cutting of DFN or QFN packages, which comprises the following steps: (1) Under normal temperature environment, the DFN or QFN package with residual UV glue after cutting is first immersed in a glue-removing solution for soaking, taken out for draining, and then washed with water; taking out the package for draining above the glue-removing solution can reduce the loss of the glue-removing solution and the water consumption in the subsequent cleaning process; the glue-removing solution comprises the following components in 100% by weight: 4-8% of alkali metal hydroxide, 4-8% of alkali metal carbonate, 8-12% of amide alcohol compounds, 38-50% of alcohol ether acetate, 22-35% of water-soluble ammonium polyphosphate, and the balance is ultrapure water; (2) Subsequently, three-stage stepped heating cleaning is carried out with ultrapure water, taken out for draining, then alcohol-washed and air-dried, and heat-baked under a protective atmosphere. The method of the present invention has a short treatment time and high efficiency for the residual glue after UV film cutting, operates below 80 °C, has no influence on the appearance of the package, the pin plating layer and the electrical performance of the product, and has a simple operation method and stable process.

Description

Technical Field

[0001] The present invention relates to the technical field of removing residual glue from electronic products, and specifically to a method for removing residual glue from the cutting of DFN or QFN packages. Background Art

[0002] With the continuous advancement of the miniaturization and chip - type of electronic component packaging, leadless DFN or QFN packages are increasingly widely used and have gradually become the key development direction of packaging enterprises. In recent years, the proportion of this series of packages has been increasing. During the packaging process of small - size DFN or QFN packages, UV films containing UV glue or directly UV glue are used. For the specific processing method of chip packaging, reference can be made to Chinese Patent 202211048169.5. Specifically, a pre - attached film (UV glue layer) is adhered to one surface of a substrate, and then cured, cut, and a metal coating is formed. Before shipment, the packages must undergo a cleaning process. However, after the UV glue is cured, the residual glue remaining after cutting is difficult to completely and effectively remove. If the residual glue from UV glue cutting is not completely removed, it will seriously affect subsequent manufacturing processes and test production, and the remaining residual glue is also difficult to remove and is likely to adhere to the product, which will have an adverse impact on the end - user.

[0003] Therefore, the removal of residual glue has become a technical problem difficult to overcome in the industry. Currently, in the industry, there are solutions such as using organic solvents such as alcohol and acetone in combination with ultrasonic heating to remove glue. However, through practice, the glue - removing effect is not very ideal, and there are mainly the following problems: the cured UV glue has weak solubility in solvents such as alcohol and acetone, and the dissolution and removal are not complete; during the ultrasonic vibration process, the corners of the packages are easily worn, resulting in damaged and missing corners of the appearance; the packages are easily discolored when soaked in heated alcohol and acetone solvents for a long time; alcohol and acetone are flammable and prone to safety accidents; the processing time is long, generally at least more than 2 hours, and the processing efficiency is low.

[0004] Therefore, peers are actively looking for and researching cleaning methods with good residual - glue removal effect, fast removal speed, and little impact on packages to solve this technical problem. Summary of the Invention

[0005] In order to solve the technical problems of poor residual - glue removal effect, low efficiency, and certain impact on packages in the existing cleaning of UV residual glue, a method for removing residual glue from the cutting of DFN or QFN packages is provided. The method of the present invention has a short processing time and high efficiency for UV - film cutting residual glue, operates below 80°C, has no impact on the appearance of the packages, the pin plating, and the electrical performance of the products, and has a simple operation method and stable process.

[0006] To achieve the above objectives, the present invention is realized through the following technical solutions:

[0007] A method for removing residual glue from the cutting of DFN or QFN packages, comprising the following steps:

[0008] (1) At normal temperature environment, first immerse the DFN or QFN package with residual UV glue after cutting into the degumming solution for soaking, take it out to drain the liquid, and then perform water washing; taking out the package to drain the liquid above the degumming solution can reduce the loss of the degumming solution and the water consumption in the subsequent cleaning process;

[0009] The degumming solution comprises the following components in 100% by weight percentage: alkali metal hydroxide 4 - 8%, alkali metal carbonate 4 - 8%, amide alcohol compound 8 - 12%, alcohol ether acetate 38 - 50%, ammonium polyphosphate 22 - 35%, and the balance is ultrapure water;

[0010] (2) Subsequently, perform three - stage stepped heating cleaning with ultrapure water, take it out to drain the liquid, then perform alcohol washing and air drying, and heat bake under a protective atmosphere.

[0011] Furthermore, the degumming solution comprises the following components in 100% by weight percentage: alkali metal hydroxide 5%, alkali metal carbonate 5%, amide alcohol compound 10%, alcohol ether acetate 40%, water - soluble ammonium polyphosphate 25%, and the balance is ultrapure water. When preparing the degumming solution, dissolve the inorganic compound in water, mix the organic compounds evenly, and then mix the two evenly.

[0012] Still further, the alkali metal hydroxide is sodium hydroxide and / or potassium hydroxide; the alkali metal carbonate is sodium carbonate and / or potassium carbonate; the amide alcohol compound is N - acetyl ethanolamine; the alcohol ether acetate is one or more of ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, and dipropylene glycol monomethyl ether acetate; the degree of polymerization n of the water - soluble ammonium polyphosphate satisfies the following relationship: 1 < n < 20, and preferably the water - soluble ammonium polyphosphate is ammonium tripolyphosphate.

[0013] Still further, the degumming solution comprises the following components in 100% by weight percentage: potassium hydroxide 5%, potassium carbonate 5%, diethylene glycol monobutyl ether acetate 40%, N - acetyl ethanolamine 10%, water - soluble ammonium polyphosphate 25%, and the balance is ultrapure water. The role of the alkali metal hydroxide in the degumming solution is to remove the grease and oxide layer on the product surface; the role of the alkali metal carbonate is to reduce the corrosion effect of the former; the alcohol ether acetate is used to dissolve the residual glue on the product; the ammonium polyphosphate is used as a slow - release agent to adjust the reaction rate, prevent the product frame from being oxidized and corroded, and for the convenience of cleaning the product after degumming; N - acetyl ethanolamine is used as a solvent to form a homogeneous phase of the degumming solution.

[0014] Further, the process of three-stage stepped heating and cleaning is as follows: First, enter ultrapure water at a temperature of 30 ± 5 °C for primary rinsing for 1 - 2 minutes, then enter ultrapure water at a temperature of 45 ± 5 °C for secondary rinsing for 1 - 2 minutes, and finally enter ultrapure water at a temperature of 60 ± 5 °C for tertiary rinsing for 3 - 5 minutes. Countercurrent water washing can be adopted to reduce water resource consumption.

[0015] Further, the soaking time is 10 - 15 minutes; the liquid draining time is 2 - 5 minutes; the water washing is carried out by spraying tap water for 3 - 5 minutes; the alcohol washing is carried out by cleaning with absolute ethanol at room temperature for 1 - 2 minutes; the air drying is carried out at room temperature for 5 - 8 minutes; the heat baking is carried out under nitrogen protection at 125 ± 5 °C for 30 ± 5 minutes.

[0016] Beneficial technical effects: The method for removing residual glue of the present invention is to soak the package in a degumming solution to completely dissolve the cutting residual glue on its surface. Subsequently, the degumming solution on the product surface is rinsed off by spraying tap water at room temperature, and then the product is successively subjected to three-stage stepped heating and cleaning at 30 ± 5 °C, 45 ± 5 °C, and 60 ± 5 °C with ultrapure water, which can effectively wash away the dissolved residual glue. Then, the product surface moisture is washed away by alcohol washing, enabling the product to be quickly air-dried. Finally, heat baking is carried out under a protective atmosphere to thoroughly dry the product. The degumming solution of the components of the present invention can quickly dissolve the cured residual glue, with a short soaking time and no need for heating, having no impact on the package and the pin plating layer. The soaking process does not require ultrasonic vibration and will not cause irreversible damage to the package. The degumming method of the present invention takes no more than 1.5 hours, has high production efficiency and a high degumming rate of up to 99%, and the process operation is simple. Specific embodiments

[0017] Hereinafter, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way limits the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0018] Unless otherwise specifically stated, the numerical values set forth in these embodiments do not limit the scope of the present invention. Technologies and methods known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such technologies and methods should be regarded as part of the specification. In all examples shown and discussed herein, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

[0019] In the following examples, the experimental methods without specific conditions are usually determined according to national standards; if there is no corresponding national standard, they are carried out according to general international standards or the standard requirements proposed by relevant enterprises. Unless otherwise specified, all parts are by weight and all percentages are by weight percentage.

[0020] Example 1

[0021] The method for removing the residual glue after cutting of a DFN package includes the following steps:

[0022] (1) Under normal temperature environment, pour the DFN package product with UV residual glue after cutting into a hollow square stainless steel basket lined with a copper mesh. The product is laid flat on the bottom of the basket and evenly dispersed, and then it is immersed in the degumming solution. The liquid level of the degumming solution covers the product. The degumming solution is composed of the following components in 100% by weight: 5% KOH, 5% K2CO3, 40% diethylene glycol monobutyl ether acetate, 10% N-acetyl ethanolamine, 25% ammonium tripolyphosphate, and the balance is ultrapure water. Immerse the product for 12 minutes. During the immersion process, the degumming solution can quickly penetrate, decompose and dissolve the residual glue;

[0023] To reduce the loss of the degumming solution and the water consumption in the subsequent cleaning process, take out the stainless steel basket and drain it above the degumming solution for 2 minutes, and then transfer it to a spraying tank for normal temperature spraying with tap water for 4 minutes. The spraying process can wash away the residual degumming solution on the surface of the product and the stainless steel basket;

[0024] (2) Subsequently, the stainless steel basket containing the product is transferred into the first rinsing tank and rinsed in ultrapure water at a temperature of 30°C for 1 minute, then transferred into ultrapure water at a temperature of 45°C for secondary rinsing for 2 minutes, and finally transferred into ultrapure water at a temperature of 60°C for tertiary rinsing for 4 minutes; the reverse flow water washing mode can be adopted to reduce water consumption;

[0025] Then take out the stainless steel basket and drain it for 5 minutes; then transfer it to a dehydration tank for normal temperature rinsing with anhydrous ethanol for 2 minutes, and then transfer it to a drying tank for dripping and air drying. At this time, most of the ethanol on the product surface volatilizes and dries; finally, transfer it to a nitrogen-filled oven and bake it at 125°C for 30 minutes until the product is dry. Take out the product from the basket, conduct appearance quality inspection, pack it into an anti-static bag and transfer it to the subsequent process.

[0026] Example 2

[0027] The method for removing the residual glue after cutting of a QFN package includes the following steps:

[0028] (1) At room temperature, pour the DFN package products with residual UV glue after cutting into a hollow square stainless-steel basket lined with copper mesh. The products are laid flat on the bottom of the basket and evenly dispersed. Then immerse them in the degumming solution. The liquid level of the degumming solution covers the products. The degumming solution is composed of the following components by weight percentage: 5% NaOH, 5% Na2CO3, 40% propylene glycol methyl ether acetate, 10% N-acetyl ethanolamine, 25% ammonium tripolyphosphate, and the balance is ultrapure water. Immerse the products for 15 minutes. During the immersion process, the degumming solution can quickly penetrate, decompose, and dissolve the residual glue;

[0029] To reduce the loss of the degumming solution and the water consumption in the subsequent cleaning process, take out the stainless-steel basket and drain it above the degumming solution for 3 minutes, and then transfer it to the spray tank for normal-temperature tap water spraying for 3 minutes. The spraying process can wash away the residual degumming solution on the surface of the products and the stainless-steel basket;

[0030] (2) Subsequently, transfer the stainless-steel basket with the products into the first rinsing tank and rinse it in ultrapure water at a temperature of 35°C for 1 minute, then transfer it into ultrapure water at a temperature of 50°C for secondary rinsing for 1 minute, and finally transfer it into ultrapure water at a temperature of 65°C for tertiary rinsing for 3 minutes; The reverse-flow water washing mode can be adopted to reduce water consumption;

[0031] Then take out the stainless-steel basket and drain it for 5 minutes; then transfer it to the dehydration tank for normal-temperature rinsing with anhydrous ethanol for 1 minute, and then transfer it to the air-drying tank for dripping and air-drying. At this time, most of the ethanol on the surface of the products volatilizes and dries; Finally, transfer it to a nitrogen-filled oven and bake it at 120°C for 35 minutes until the products are dry. Take out the products from the basket, conduct appearance quality inspection, pack them into anti-static bags and transfer them to the subsequent process.

[0032] Example 3

[0033] A method for removing cutting residual glue of DFN packages includes the following steps:

[0034] (1) At room temperature, pour the DFN package products with residual UV glue after cutting into a hollow square stainless-steel basket lined with copper mesh. The products are laid flat on the bottom of the basket and evenly dispersed. Then immerse them in the degumming solution. The liquid level of the degumming solution covers the products. The degumming solution is composed of the following components by weight percentage: 8% KOH, 4% K2CO3, 38% dipropylene glycol methyl ether acetate, 8% N-acetyl ethanolamine, 35% ammonium tripolyphosphate, and the balance is ultrapure water. Immerse the products for 12 minutes. During the immersion process, the degumming solution can quickly penetrate, decompose, and dissolve the residual glue;

[0035] To reduce the loss of the degumming solution and the water consumption in the subsequent cleaning process, take out the stainless-steel basket and drain it above the degumming solution for 2 minutes, then transfer it to the spray tank for normal-temperature tap water spraying for 4 minutes. The spraying process can wash away the residual degumming solution on the surface of the product and the stainless-steel basket;

[0036] (2) Subsequently, the stainless-steel basket containing the product is transferred into the first rinsing tank and rinsed in ultrapure water at a temperature of 30°C for 1 minute, then transferred into ultrapure water at a temperature of 45°C for secondary rinsing for 2 minutes, and finally transferred into ultrapure water at a temperature of 60°C for tertiary rinsing for 4 minutes; The countercurrent water washing mode can be adopted to reduce water consumption;

[0037] Subsequently, take out the stainless-steel basket and drain it for 5 minutes; then transfer it to the dehydration tank for normal-temperature rinsing with anhydrous ethanol for 2 minutes, and then transfer it to the air-drying tank for dripping and air-drying. At this time, most of the ethanol on the product surface volatilizes and dries; Finally, transfer it to a nitrogen-filled oven and bake it at 125°C for 30 minutes until the product is dry. Take out the product from the basket, conduct appearance quality inspection, pack it into an anti-static bag and transfer it to the subsequent process.

[0038] Example 4

[0039] The method for removing the cutting residual glue of the DFN package includes the following steps:

[0040] (1) Under normal-temperature environment, pour the DFN package product with residual UV glue after cutting into a hollow square stainless-steel basket lined with a copper mesh. The product is laid flat on the bottom of the basket and evenly dispersed, and then it is immersed in the degumming solution. The liquid level of the degumming solution covers the product. The degumming solution is composed of the following components by weight percentage: 4% KOH, 8% K2CO3, 45% ethylene glycol monoethyl ether acetate, 12% N-acetylethanolamine, 22% ammonium tripolyphosphate, and the balance is ultrapure water. Immerse the product for 12 minutes. During the immersion process, the degumming solution can quickly penetrate, decompose and dissolve the residual glue;

[0041] To reduce the loss of the degumming solution and the water consumption in the subsequent cleaning process, take out the stainless-steel basket and drain it above the degumming solution for 2 minutes, then transfer it to the spray tank for normal-temperature tap water spraying for 4 minutes. The spraying process can wash away the residual degumming solution on the surface of the product and the stainless-steel basket;

[0042] (2) Subsequently, the stainless-steel basket containing the product is transferred into the first rinsing tank and rinsed in ultrapure water at a temperature of 30°C for 1 minute, then transferred into ultrapure water at a temperature of 45°C for secondary rinsing for 2 minutes, and finally transferred into ultrapure water at a temperature of 60°C for tertiary rinsing for 4 minutes; The countercurrent water washing mode can be adopted to reduce water consumption;

[0043] Subsequently, take out the stainless-steel basket and let it drip for 5 minutes; then transfer it to the dehydration tank for rinsing with anhydrous ethanol at room temperature for 2 minutes, and then transfer it to the air-drying tank to drip and air-dry. At this time, most of the ethanol on the product surface volatilizes and dries; finally, transfer it to a nitrogen-filled oven and bake it at 125 °C for 30 minutes until the product is dry. Take out the product from the basket, conduct appearance quality inspection, pack it into an anti-static bag and transfer it to the subsequent process.

[0044] Comparative Example 1

[0045] The degumming method of this comparative example is the same as that of Example 1, except that the degumming solution in Step 1 is composed of the following components in 100% weight percentage: 85% acetone, 15% ultrapure water. The temperature of the degumming solution is 50 °C, and ultrasonic vibration is assisted. The ultrasonic power is 100 W, and the soaking time is 1.5 h.

[0046] Comparative Example 2

[0047] The degumming method of this comparative example is the same as that of Example 1, except that the degumming solution in Step 1 is composed of the following components in 100% weight percentage: 10% KOH, 75% acetone, and the balance is ultrapure water. The temperature of the degumming solution is 50 °C, and the soaking time is 2 h.

[0048] Comparative Example 3

[0049] The degumming method of this comparative example is the same as that of Example 1, except that the degumming solution in Step 1 is composed of the following components in 100% weight percentage: 10% KOH, 75% ethanolamine, and the balance is ultrapure water. The soaking time is 2 h.

[0050] Detect the residual gum removal rate, product appearance, and whether there are changes in product resistance of the products in the above examples and comparative examples. The results are shown in Table 1.

[0051] Table 1 Influence of the degumming schemes of examples and comparative examples on products

[0052]

[0053] As can be seen from Table 1, using the degumming solution with the formula of the present invention in combination with the overall degumming process of the present invention can quickly remove the residual gum, and the removal rate reaches more than 95%, reducing the time cost and increasing the product yield.

[0054] As mentioned above, the above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered within the protection scope of the present invention.

Claims

1. A method for removing residual glue from a DFN or QFN package cutting, characterized in that, It includes the following steps: (1) At normal temperature, the DFN or QFN package with residual UV glue after cutting is first immersed in the degumming solution for soaking, taken out for draining, and then washed with water; The degumming solution includes the following components in 100% by weight: alkali metal hydroxide 4 - 8%, alkali metal carbonate 4 - 8%, amide alcohol compound 8 - 12%, alcohol ether acetate 38 - 50%, water-soluble ammonium polyphosphate 22 - 35%, and the balance is ultrapure water; The alkali metal hydroxide is sodium hydroxide and / or potassium hydroxide; The alkali metal carbonate is sodium carbonate and / or potassium carbonate; The amide alcohol compound is N-acetylethanolamine; The alcohol ether acetate is one or more of ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, and dipropylene glycol monomethyl ether acetate; The polymerization degree n of the water-soluble ammonium polyphosphate satisfies the following relationship: 1 < n < 20; (2) Subsequently, it is subjected to three-stage stepped heating and cleaning with ultrapure water, taken out for draining, then alcohol-washed and air-dried, and heat-baked under a protective atmosphere; The process of the three-stage stepped heating and cleaning is as follows: first enter the ultrapure water at a temperature of 30 ± 5°C for the first-stage rinsing for 1 - 2 min, then enter the ultrapure water at a temperature of 45 ± 5°C for the second-stage rinsing for 1 - 2 min, and finally enter the ultrapure water at a temperature of 60 ± 5°C for the third-stage rinsing for 3 - 5 min.

2. The method for removing residual glue after cutting of the DFN or QFN package according to claim 1, characterized in that, The degumming solution includes the following components in 100% by weight: alkali metal hydroxide 5%, alkali metal carbonate 5%, amide alcohol compound 10%, alcohol ether acetate 40%, water-soluble ammonium polyphosphate 25%, and the balance is ultrapure water.

3. The method for removing residual glue after cutting of the DFN or QFN package according to claim 1, characterized in that The degumming solution includes the following components in 100% by weight: potassium hydroxide 5%, potassium carbonate 5%, N-acetylethanolamine 10%, diethylene glycol monobutyl ether acetate 40%, water-soluble ammonium polyphosphate 25%, and the balance is ultrapure water.

4. The method for removing residual glue from a DFN or QFN package according to any one of claims 1-3, characterized in that, The soaking time is 10 - 15 min; the draining time is 2 - 5 min; the water washing is carried out by spraying tap water for 3 - 5 min; the alcohol washing is carried out by cleaning with absolute ethanol at normal temperature for 1 - 2 min; the air drying is carried out at normal temperature for 5 - 8 min; the heat baking is carried out under nitrogen protection at 125 ± 5°C for 30 ± 5 min.

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