Residual glue prevention silica gel belt for semiconductor mold sealing and preparation method of residual glue prevention silica gel belt

Abstract

The invention discloses an anti-adhesive-residue silica gel belt for semiconductor mold sealing and a preparation method thereof. The preparation method comprises the following steps: mixing hydrogen-containing silicone oil, a vinyl monomer containing an epoxy group, a platinum catalyst and a first solvent for reaction to obtain hydrogen-containing silicone oil containing the epoxy group; mixing the epoxy group-containing hydrogen-containing silicone oil with vinyl-containing silicone rubber, methyl MQ resin, an inhibitor and a second solvent to obtain organic silicon adhesive coating liquid; and coating a PI film substrate with the organic silica gel adhesive coating liquid, drying and curing, and attaching a fluorine release film to obtain the adhesive residue prevention silica gel belt. Hydrogen-containing silicone oil containing epoxy groups serves as a cross-linking agent and reacts with vinyl-containing silicone rubber and methyl MQ resin to prepare the organic silicon adhesive, the epoxy groups chemically react with active groups on a PI base material in the drying process, the adhesive force of an organic silicon adhesive layer and a PI film is increased, and after mold sealing is finished, due to the fact that the adhesive layer is high in adhesive force with the base material, the adhesive layer can be easily separated from the PI film. Therefore, the occurrence of adhesive residue when the adhesive tape is torn off can be overcome.

Description

Technical Field

[0001] The invention relates to the technical field of silicone tapes, and in particular to an anti-residue adhesive silicone tape for semiconductor mold sealing and a preparation method thereof. Background Art

[0002] In the semiconductor field, high temperature resistant silicone tape is often used as protective tape during the process of leadless packaging (such as the quad flat leadless package QFN) to prevent the epoxy molding compound from overflowing to the pins during the molding process. The molded samples need to be baked at high temperature, and the epoxy molding compound must be completely cured to block the external water and oxygen and protect the packaged objects. In order to prevent stress and damage to the chip and leads in the packaged frame during the process of removing the protective tape, the protective tape is usually torn off after the epoxy molding compound is cured at high temperature.

[0003] High temperature resistant silicone tape often uses PI (polyimide) film as the tape substrate, but the adhesion between organic silicone adhesive and PI substrate is poor. The epoxy molding compound used for leadless packaging contains more epoxy functional groups, and the silicone tape used as a protective tape for mold sealing often contains active hydrogen. During the high temperature aging process, the reaction between epoxy groups and active hydrogen leads to increased adhesion. When tearing the film, due to the poor bonding between the adhesive layer and the PI film, residual glue is likely to appear, resulting in the product being unusable.

[0004] In order to improve the adhesion between PI substrate and silicone adhesive, anchoring agents are often added to the formula when coating the silicone adhesive layer. However, anchoring agents are small molecules and chemical reactions only occur during the coating and drying process. The reaction rate is not high, resulting in insignificant improvement in adhesion. The addition of too much anchoring agent will lead to the residue of reactive functional groups and the precipitation of small molecules.

[0005] Therefore, it is of great significance to research and develop a semiconductor mold sealing silicone tape that is not prone to residual adhesive when removing the tape after high-temperature aging. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention provides a semiconductor mold sealing anti-residue adhesive silicone tape and a preparation method thereof, wherein a monomer containing epoxy groups and vinyl functional groups is reacted with hydrogen-containing silicone oil to prepare hydrogen-containing silicone oil containing epoxy groups as a crosslinking agent, and then reacted with vinyl-containing silicone rubber and methyl MQ resin to prepare organic silicone adhesive. The epoxy groups in the hydrogen-containing silicone oil containing epoxy groups can react chemically with the active groups on the PI substrate during the preparation and drying of the tape, thereby increasing the adhesion between the organic silicone adhesive layer and the substrate PI film. As a mold sealing protective tape, after the mold sealing is completed, the adhesive layer has strong adhesion to the substrate, thereby overcoming the occurrence of residual adhesive when the tape is torn off.

[0007] In order to solve the above technical problems, the present invention provides a method for preparing an anti-residue adhesive silicone tape for semiconductor mold sealing, comprising the following steps:

[0008] S1, mixing hydrogen-containing silicone oil, epoxy-containing vinyl monomer, platinum catalyst and a first solvent, and reacting at 30-80° C. for 2-5 hours to obtain hydrogen-containing silicone oil containing epoxy groups;

[0009] S2, mixing the hydrogen-containing silicone oil containing epoxy groups with vinyl-containing silicone rubber, methyl MQ resin, an inhibitor and a second solvent to obtain an organic silicone adhesive coating liquid;

[0010] S3. The organic silicone adhesive coating liquid is coated on the PI film substrate through a coating process, and after drying and curing in an oven and cooling, a fluorine release film is attached to the adhesive side to obtain the anti-residue silicone tape for semiconductor mold sealing.

[0011] The present invention reacts a monomer containing epoxy groups and vinyl functional groups with hydrogen-containing silicone oil to prepare hydrogen-containing silicone oil containing epoxy groups as a crosslinking agent, and then reacts with vinyl-containing silicone rubber and methyl MQ resin to prepare organic silicone adhesive. The hydrogen-containing silicone oil containing epoxy groups reacts with the vinyl-containing silicone rubber to form a crosslinking reaction, and the methyl MQ resin is used as a reinforcing agent to adjust the peeling force of the organic silicone adhesive; the epoxy group in the hydrogen-containing silicone oil containing epoxy groups reacts chemically with the active group (mainly referring to the NH chemical bond in the amide group) on the PI substrate during the subsequent drying and curing process of preparing the tape, thereby increasing the adhesion between the organic silicone adhesive layer and the substrate PI film. As a mold-sealed protective tape, after the mold-sealing is completed, the adhesive layer has a strong adhesion to the substrate, thereby overcoming the occurrence of residual glue when the tape is torn off.

[0012] The present invention uses a platinum catalyst as a reaction accelerator when preparing a crosslinking agent containing an epoxy group of hydrogen-containing silicone oil. After the reaction is completed, the platinum catalyst does not need to be removed and can be used again as a catalyst when preparing an organic silicone adhesive layer. The catalyst is used twice, the operation steps are reduced, and the cost is saved.

[0013] Furthermore, the structural formula of the hydrogen-containing silicone oil is: The structural formula of the epoxy group-containing vinyl monomer is: The structural formula of the vinyl-containing silicone rubber is:

[0014] The reaction formula of S1 is:

[0015]

[0016] The reaction formula of S2 is:

[0017]

[0018] Wherein, R1 and R2 are independently selected from H or -CH3, R3 and R4 are ester groups, alkyl groups or ether bonds, R5 and R6 are independently selected from vinyl groups or methyl groups; a~f are selected from positive integers.

[0019] Furthermore, in S1, the molar ratio of hydrogen to vinyl in the hydrogen-containing silicone oil and the epoxy group-containing vinyl monomer is 1:(0.1-1):0.9, preferably 1:(0.2-1):0.9.

[0020] Furthermore, in S1, the epoxy group-containing vinyl monomer is glycidyl acrylate and / or allyl glycidyl ether.

[0021] Furthermore, in S1, the mass fraction of hydrogen in the hydrogen-containing silicone oil is 0.2%-2.5%, preferably 0.5%-1.5%.

[0022] Furthermore, in S2, the mass fraction of vinyl in the vinyl-containing silicone rubber is 0.03%-0.8%, and the molecular weight is 500,000-1,000,000, preferably 600,000-800,000.

[0023] Furthermore, in S2, the molar ratio of M to Q in the methyl MQ resin is 0.5-1, and the molecular weight is 3000-8000.

[0024] Further, in S3, temperature zones of 70°C, 100°C, 140°C, 150°C, 120°C, and 60°C are sequentially arranged in the oven, and each temperature zone is 2±0.2 m long.

[0025] Further, in S3, the PI film is subjected to corona treatment on the side to be coated before coating, and the corona surface dyne value is greater than 58;

[0026] And / or, the coating rate is 3±0.5 m / min.

[0027] Further, the platinum catalyst is chloroplatinic acid and / or Custer platinum catalyst, preferably Custer platinum catalyst, and the platinum content is 1000ppm to 5000ppm;

[0028] And / or, the inhibitor is one or more of 3-methyl-1-butyn-3-ol, 1-butynylcyclohexanol, 3-phenyl-1-butyn-3-ol, and quinoline, preferably 3-methyl-1-butyn-3-ol.

[0029] Furthermore, the first solvent and the second solvent are independently selected from toluene or xylene.

[0030] The second aspect of the present invention provides an anti-residue adhesive silicone tape for semiconductor mold sealing prepared by the preparation method described in the first aspect.

[0031] Beneficial effects of the present invention:

[0032] The present invention reacts a monomer containing epoxy groups and vinyl functional groups with hydrogen-containing silicone oil to prepare hydrogen-containing silicone oil containing epoxy groups as a crosslinking agent, and then reacts with vinyl-containing silicone rubber and methyl MQ resin to prepare an organic silicone adhesive. The epoxy group in the hydrogen-containing silicone oil containing epoxy groups reacts chemically with the active group (NH chemical bond) on the PI substrate during the subsequent drying and curing process of preparing the adhesive tape, thereby increasing the adhesion between the organic silicone adhesive layer and the substrate PI film, thereby overcoming the occurrence of residual adhesive when the tape is torn off.

[0033] The hydrogen-containing silicone oil containing epoxy groups in the present invention is used as a crosslinking agent to react with the vinyl-containing silicone rubber, and the methyl MQ resin is used as a reinforcing agent to adjust the peeling force of the organic silicone adhesive.

[0034] The present invention uses a platinum catalyst as a reaction accelerator when preparing a crosslinking agent containing epoxy group-containing hydrogenated silicone oil. After the reaction is completed, the platinum catalyst does not need to be removed and can be used again as a catalyst when preparing an organic silicone adhesive layer. The catalyst is used twice, which reduces the operation steps and saves costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 It is a schematic structural diagram of the anti-residue adhesive silicone tape for semiconductor mold sealing of the present invention;

[0037] Explanation of the numbers in the figure: 1. Fluorine release film, 2. Adhesive layer, 3. PI film. DETAILED DESCRIPTION

[0038] The technical solution of the present invention will be described clearly and completely below in conjunction with the specific embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] Example 1

[0040] This embodiment relates to a method for preparing an anti-residue adhesive silicone tape for semiconductor mold sealing, comprising the following steps:

[0041] (1) Preparation of hydrogenated silicone oil containing epoxy groups: 22 parts of hydrogenated silicone oil (hydrogen content 0.8%), 10 parts of allyl glycidyl ether, 1 part of Custer platinum catalyst (platinum content 3000 ppm) and 74.6 parts of xylene were added into a reaction kettle and mixed and stirred, and the temperature was raised to 50° C. for reaction for 5 hours. The reaction liquid was cooled to room temperature to obtain a hydrogenated silicone oil solution containing epoxy groups, at which the mass fraction of the solution was 30%, the hydrogen content of the solution was 0.083%, and the molar ratio of epoxy groups to silicon-hydrogen bonds was 1:2;

[0042] (2) Preparation of organic silicone adhesive coating liquid: 10 parts of the hydrogenated silicone oil solution containing epoxy groups prepared in step (1) were mixed with 30 parts of vinyl-containing silicone rubber (vinyl content 0.35%, weight average molecular weight 600,000), 7.5 parts of methyl MQ resin (SI-MQ102, Shengbang Organic Silicone Technology Co., Ltd.), 0.03 parts of 3-methyl-1-butyn-3-ol and 87.5 parts of xylene, and stirred at room temperature until completely and evenly dissolved to obtain an organic silicone adhesive coating liquid with a solid content of 30%, wherein the molar ratio of vinyl to silicon-hydrogen bond is 1:1.2;

[0043] (3) corona treating the PI film until the corona value is 60, and coating the organic silicone adhesive coating liquid obtained in step (2) on the corona surface of the polyimide-based film by micro-dimpled coating at a speed of 3 m / min, and the thickness of the coated adhesive layer is 10 μm;

[0044] (4) Drying treatment: the oven is set with temperature zones of 70°C, 100°C, 140°C, 150°C, 120°C, and 60°C from front to back, and each temperature zone is 2m long;

[0045] (5) After cooling, a fluorine release film is attached to the adhesive side to obtain a semiconductor mold sealing anti-residue silicone tape having a fluorine release film 1, an adhesive layer 2, and a PI film 3 laminated in sequence, with a structure as shown in FIG. Figure 1 shown.

[0046] Example 2

[0047] The difference between this embodiment and embodiment 1 is that the addition amount of allyl glycidyl ether is adjusted to 11 parts, and other steps and parameters remain unchanged, so as to prepare a semiconductor mold sealing anti-residue silicone tape with a PI film, an adhesive layer, and a fluorine release film laminated in sequence.

[0048] Example 3

[0049] The difference between this embodiment and embodiment 1 is that the hydrogen content of the hydrogen-containing silicone oil in step (1) is 1.2%, the amount of hydrogen-containing silicone oil solution containing epoxy groups added in step (2) is adjusted to 5 parts, the molar ratio of vinyl to silicon-hydrogen bond in the obtained organic silicone adhesive coating liquid is consistent with that in embodiment 1, the other steps and parameters remain unchanged, and the anti-residue silicone tape for semiconductor mold sealing is prepared by sequentially stacking a PI film, an adhesive layer, and a fluorine release film.

[0050] Example 4

[0051] The difference between this embodiment and embodiment 1 is that the addition amount of methyl MQ resin is adjusted to 12.8 parts, the addition amount of xylene is adjusted to 100 parts, and other steps and parameters remain unchanged, and the anti-residue adhesive silicone tape for semiconductor mold sealing is prepared by sequentially stacking PI film, adhesive layer, and fluorine release film.

[0052] Comparative Example 1

[0053] The difference between this comparative example and Example 1 is that the synthesis of hydrogenated silicone oil containing epoxy groups in step (1) is not performed, and the preparation steps of the organic silicone adhesive coating liquid in step (2) are as follows: 30 parts of vinyl-containing silicone rubber (vinyl content 0.35%, weight average molecular weight 600,000), 7.5 parts of methyl MQ resin (SI-MQ102, Shengbang Organic Silicone Technology Co., Ltd.), 2 parts of hydrogenated silicone oil (hydrogen content 0.8%), 0.003 parts of 3-methyl-1-butyn-3-ol, 0.01 parts of platinum catalyst, and 92 parts of xylene are stirred at room temperature to completely and evenly dissolve to obtain an organic silicone adhesive coating liquid. The other parameters and steps remain unchanged, and a semiconductor mold sealing silicone tape with a PI film, an adhesive layer, and a fluorine release film is prepared in sequence.

[0054] Comparative Example 2

[0055] The difference between this comparative example and comparative example 1 is that the addition amount of methyl MQ resin is adjusted to 12.8 parts, the addition amount of xylene is adjusted to 100 parts, and other steps and parameters remain unchanged, and a silicone tape for semiconductor mold sealing is prepared by sequentially laminating a PI film, an adhesive layer, and a fluorine release film.

[0056] Test Case

[0057] The silicone tapes prepared in Examples 1-4 and Comparative Examples 1-2 were attached to the surface of a copper plate of the same material as the frame to perform a 180° peel test to measure the peel strength at room temperature, which was used to indicate the adhesive force of the tape to the frame. The specific steps are as follows: attach the prepared tape to a copper plate (made of CW-003A), and use an electronic tensile tester to test the 180° peel strength at a temperature of 25°C±1°C and a humidity of 50%±5%.

[0058] The silicone tape was attached to the silver-plated copper lead frame, and the lead frame was molded with epoxy molding compound. After molding, it was baked and cured at 180°C for 6 hours. After the baking, it was cooled to room temperature, the silicone tape was torn off, and whether there was any overflow of the molding compound and whether there was any residual glue on the protected surface of the frame were observed under a 100x microscope. The results are shown in Table 1.

[0059]

[0060] As shown in Table 1, the silicone tapes prepared in Examples 1-4 had no plastic encapsulation material overflow, and after the plastic encapsulation material was cured at high temperature, no residual glue was left when the silicone tape was torn off. This is because the organic silicone adhesive layer contains epoxy groups, and the introduction of epoxy groups reacts chemically with the active groups (NH chemical bonds) on the PI substrate during the subsequent drying and curing process of the tape, thereby increasing the adhesion between the organic silicone adhesive layer and the substrate PI film, and there is no residual glue after the film is torn off; at the same time, the introduction of epoxy groups increases the bonding force between the silicone tape and the lead frame, inhibiting the overflow of the plastic encapsulation material.

[0061] Comparing Example 1 with Example 4, the peeling force increases with the increase of the methyl MQ resin content.

[0062] From the comparison between Example 1 and Comparative Example 1, and between Example 4 and Comparative Example 2, it can be seen that no epoxy group is introduced in Comparative Example 1 and Comparative Example 2, the adhesion between the silicone adhesive and the PI film is poor, and residual glue appears when the tape is removed after molding. In addition, due to the low bonding strength between the silicone adhesive and the lead frame at high temperature, glue overflow also occurs.

[0063] In summary, the present invention reacts a monomer containing epoxy groups and vinyl functional groups with hydrogenated silicone oil to prepare hydrogenated silicone oil containing epoxy groups as a crosslinking agent, and then reacts with vinyl-containing silicone rubber and methyl MQ resin to prepare organic silicone adhesive. The epoxy group in the hydrogenated silicone oil containing epoxy groups reacts chemically with the active group (NH chemical bond) on the PI substrate during the subsequent drying and curing process of preparing the tape, thereby increasing the adhesion between the organic silicone adhesive layer and the substrate PI film, thereby overcoming the occurrence of residual glue when the tape is torn off; the hydrogenated silicone oil containing epoxy groups is used as a crosslinking agent to react with the vinyl-containing silicone rubber, and the methyl MQ resin is used as a reinforcing agent to adjust the peeling force of the organic silicone adhesive; when preparing the hydrogenated silicone oil containing epoxy groups as a crosslinking agent, a platinum catalyst is used as a reaction accelerator, and the platinum catalyst does not need to be removed after the reaction is completed, and can be used again as a catalyst when preparing the organic silicone adhesive layer; the catalyst is used twice, reducing the operation steps and saving costs.

[0064] The present invention has been described in detail above in conjunction with specific implementations and exemplary examples, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, a variety of equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing an anti-residue adhesive silicone tape for semiconductor mold sealing, characterized in that: The steps include: S1, mixing hydrogen-containing silicone oil, epoxy-containing vinyl monomer, platinum catalyst and a first solvent, and reacting at 30-80° C. for 2-5 hours to obtain hydrogen-containing silicone oil containing epoxy groups; S2, mixing the hydrogen-containing silicone oil containing epoxy groups with vinyl-containing silicone rubber, methyl MQ resin, an inhibitor and a second solvent to obtain an organic silicone adhesive coating liquid; S3. The organic silicone adhesive coating liquid is coated on the PI film substrate through a coating process, and after drying and curing in an oven and cooling, a fluorine release film is attached to the adhesive side to obtain the anti-residue silicone tape for semiconductor mold sealing.

2. The method for preparing the anti-residue adhesive silicone tape for semiconductor mold sealing according to claim 1, characterized in that: In S1, the molar ratio of hydrogen to vinyl in the hydrogen-containing silicone oil and the epoxy group-containing vinyl monomer is 1:(0.1-1):0.

9.

3. The method for preparing the anti-residue adhesive silicone tape for semiconductor mold sealing according to claim 1, characterized in that: In S1, the epoxy group-containing vinyl monomer is glycidyl acrylate and / or allyl glycidyl ether.

4. The method for preparing the anti-residue adhesive silicone tape for semiconductor mold sealing according to claim 1, characterized in that: In S1, the mass fraction of hydrogen in the hydrogen-containing silicone oil is 0.2%-2.5%.

5. The method for preparing the anti-residue adhesive silicone tape for semiconductor mold sealing according to claim 1, characterized in that: In S2, the mass fraction of vinyl in the vinyl-containing silicone rubber is 0.03%-0.8%, and the molecular weight of the vinyl-containing silicone rubber is 500,000-1,000,000.

6. The method for preparing the anti-residue adhesive silicone tape for semiconductor mold sealing according to claim 1, characterized in that: In S2, the molar ratio of M to Q in the methyl MQ resin is 0.5-1, and the molecular weight of the methyl MQ resin is 3000-8000.

7. The method for preparing the anti-residue adhesive silicone tape for semiconductor mold sealing according to claim 1, characterized in that: In S3, temperature zones of 70°C, 100°C, 140°C, 150°C, 120°C, and 60°C are sequentially arranged in the oven, and each temperature zone is 2±0.2 m long.

8. The method for preparing the anti-residue adhesive silicone tape for semiconductor mold sealing according to claim 1, characterized in that: In S3, the PI film is subjected to corona treatment on the side to be coated before coating, and the corona surface dyne value is greater than 58; And / or, the coating rate is 3±0.5 m / min.

9. The method for preparing the anti-residue adhesive silicone tape for semiconductor mold sealing according to claim 1, characterized in that: The platinum catalyst is chloroplatinic acid and / or Custer platinum catalyst; And / or, the inhibitor is one or more of 3-methyl-1-butyn-3-ol, 1-butynylcyclohexanol, 3-phenyl-1-butyn-3-ol, and quinoline.

10. An anti-residue silicone tape for semiconductor mold sealing prepared by the preparation method according to any one of claims 1 to 9.

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