A hot-melt polyimide adhesive layer, a hot-melt polyimide tape, and a method for preparing the same.

Abstract

This disclosure relates to a hot-melt polyimide adhesive layer, a hot-melt polyimide tape, and a method for preparing the same. The glass transition temperature of the hot-melt polyimide adhesive layer is 150-200°C. By controlling the proportions of BAPP in the diamine and TMEG in the dianhydride, and using a small amount of siloxane diamine (especially PSX), the hot-melt polyimide adhesive layer of this application can achieve the target adhesion strength (high adhesion) with the leadframe, while ensuring a glass transition temperature of 150-200°C and good release properties (ensuring no residue remains on the leadframe when removing the tape after semiconductor packaging). This effectively prevents the back of the leadframe from being penetrated by the encapsulation resin during the packaging process.

Description

Technical Field

[0001] This disclosure relates to the field of polyimide technology, specifically to hot-melt polyimide adhesive layers, hot-melt polyimide tapes for semiconductor packaging, and their preparation methods. Background Technology

[0002] Polyimide materials are widely used in electrical and electronic materials, aerospace, aviation, telecommunications and other fields due to their excellent mechanical, thermal dimensional stability and chemical stability.

[0003] Furthermore, a novel semiconductor packaging structure is currently under development that encapsulates only one side of the semiconductor, leaving the exposed leadframe on the other side as an external connection interface. This semiconductor packaging structure offers significant advantages: since the leadframe does not protrude from the encapsulating resin (epoxy resin), a lightweight design can be achieved. However, it is important to note that during the encapsulation process, the encapsulating resin may seep into the other side of the leadframe, and this undesirable phenomenon still poses a potential risk.

[0004] To address this, the following measures were taken: Before the semiconductor packaging process, polyimide tape was applied to the lead frame, and then the packaging process was carried out; after the packaging process was completed, the polyimide tape was peeled off, thereby effectively preventing the packaging resin from seeping into the back of the lead frame.

[0005] Typically, polyimide tape has the following structure: a hot-melt polyimide adhesive layer is applied to a polyimide substrate film, and this hot-melt polyimide adhesive layer is laminated onto the lead frame (SUS). In this process, the encapsulation step after attaching the polyimide tape to the back of the lead frame usually needs to be performed at a relatively high temperature. However, during encapsulation, the hot-melt polyimide adhesive layer may peel off from the substrate film or deform due to heat melting, making it difficult to peel off from the lead frame after encapsulation, resulting in residue problems. Summary of the Invention

[0006] In a first aspect, this disclosure provides a hot-melt polyimide adhesive layer, wherein the glass transition temperature of the hot-melt polyimide adhesive layer is 150~200°C; When the hot-melt polyimide adhesive layer is attached to the lead frame for semiconductor packaging, the initial adhesive strength with the lead frame after the bonding process is above 100 gf / cm, and the adhesive strength with the lead frame after the wire bonding process is above 400 gf / cm.

[0007] In some embodiments, the hot-melt polyimide adhesive layer is polymerized from a monomer composition comprising an aromatic diamine monomer, an aromatic dianhydride monomer, and a siloxane diamine; The aromatic diamine is selected from p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, 2,2'-bis[4-(3-aminophenoxy)phenyl]propane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, bis(3-aminophenyl)sulfone, bis(4-aminophenyl)sulfone, trimethylene bis(4-aminobenzoic acid ester), 1,5-diaminonaphthalene, bis[4-(3-aminophenoxy)phenyl]sulfone, 4-(4-aminophenoxy)phenyl]sulfone, 2,5-dimethyl-1,4-phenylenediamine, 2,2'-dimethylbenzidine, 3,3'-dimethylbenzidine, 4-aminophenyl-4-aminobenzoic acid ester, 1,3-bis(3-aminophenyl ... The aromatic diamine comprises one or more of the following: 3,3'-dihydroxy-4,4'-diaminobiphenyl, 4,4'-diaminobenzoyl aniline, 3,5-diaminobenzoic acid, 4,4'-diamino-(1,1'-biphenyl)-2,2'-dicarboxylic acid, m-xylenediamine, 4,4'-bis(4-aminophenoxy)benzophenone, 4,4'-bis(4-aminophenoxy)biphenyl, 2,2'-bis(trifluoromethyl)benzidine, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 4,4'-diamino-2,2'-bis(trifluoromethyl)diphenyl ether, and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane; wherein, in the aromatic diamine, 2,2-bis[4-(4-aminophenoxy)phenyl]propane accounts for more than 70 mol% of the total molar percentage of the diamine monomer. The aromatic dianhydride is selected from one or more of the following: benzoyl tetracarboxylic dianhydride, biphenyl tetracarboxylic dianhydride, bisphenol A type diether dianhydride, hexafluoroisopropylidene dianhydride, 4,4′-oxo-bihydric dianhydride, benzophenone tetracarboxylic dianhydride, ethylene glycol bis(4-triphenyltriacyl anhydride), diphenyl sulfone tetracarboxylic dianhydride, and naphthalene-2,3,6,7-tetracarboxylic dianhydride, wherein ethylene glycol bis(4-triphenyltriacyl anhydride) accounts for more than 70 mol% of the total molar percentage of the dianhydride monomer; And / or, the molar ratio of total diamine monomer to total dianhydride monomer is 1.1:0.9 to 0.9:1.1.

[0008] In some embodiments, the siloxane diamine is a polydimethylsiloxane with diamino-terminated ends having the following formula: Where R is C 1-20 Alkylene, where n is an integer from 1 to 20; preferably, R is methylene, 1,2-ethylene, 1,3-propylene, 1,4-butylene, or 1,6-hexylene; Preferably, the siloxane diamine is a bis(γ-aminopropyl)polydimethylsiloxane with a weight-average molecular weight (Mw) of 500-1200; Preferably, the siloxane diamine accounts for 5 mol% to 20 mol% of the total molar amount of the diamine monomer.

[0009] Secondly, this disclosure relates to a hot melt polyimide tape, which includes a substrate film and a hot melt polyimide adhesive layer according to the first aspect of this application.

[0010] In some embodiments, the substrate film is a polyimide substrate film; Preferably, the thickness of the polyimide substrate film is 5-100 micrometers. And / or, the thickness of the hot-melt polyimide adhesive layer is 0.1~2 micrometers; Preferably, the hot melt polyimide tape is used for semiconductor packaging.

[0011] Thirdly, this disclosure relates to a method for preparing hot-melt polyimide tape according to the first aspect of this disclosure, comprising the following steps: S1. To form a polyamic acid from a monomer composition, said monomer composition comprising an aromatic diamine monomer, an aromatic dianhydride monomer, and a siloxane diamine; S2. The polyamic acid is coated on one surface of a substrate film and cured by heat treatment to form a hot-melt polyimide adhesive layer; Preferably, the temperature of the heat treatment is 60~300℃; and / or the total time of the heat treatment is 10~180 minutes; Preferably, the heat treatment is a multi-stage heat treatment.

[0012] In some implementations, S1 includes: S11. Dissolve the aromatic dianhydride and the aromatic diamine in the first organic solvent to carry out the first reaction; S12. Add a second organic solvent and siloxane diamine to the contents of the first reaction to carry out a second reaction and obtain the polyamic acid; Preferably, the temperature of the first reaction is 25~70°C, and / or the time of the first reaction is 4~8 hours; Preferably, the temperature of the second reaction is 25~70°C, and / or the time of the second reaction is 12~24 hours.

[0013] In some embodiments, the first organic solvent is selected from one or more of N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, N,N-dimethylformamide, tetrahydrofuran, N,N-diethylformamide, N-ethyl-2-pyrrolidone, N,N-diethylacetamide, and N,N-dimethylpropionamide; And / or, the second organic solvent is selected from one or more of xylene, benzene, toluene, cyclohexanone, diethylbenzene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, diethylene glycol, triethylene glycol, n-hexane, n-heptane, n-octane, n-nonane, n-decane, n-undecane, and n-dodecane; And / or, the weight ratio of the first organic solvent to the second organic solvent is 5:5 to 9:1.

[0014] In some embodiments, the solid content of the polyamic acid is 5 to 25 wt%.

[0015] Fourthly, this disclosure relates to a structure for semiconductor packaging, including a lead frame and a hot melt polyimide tape of this disclosure, wherein the hot melt polyimide tape is attached to a surface of the lead frame via a hot melt polyimide adhesive layer. The initial bonding strength between the hot-melt polyimide adhesive layer and the lead frame after the bonding process is above 100 gf / cm, and the bonding strength between the hot-melt polyimide adhesive layer and the lead frame after the lead bonding process is above 400 gf / cm.

[0016] This application's hot-melt polyimide adhesive layer achieves the target adhesion strength (high adhesion) with the leadframe by controlling the proportion of BAPP in the diamine and TMEG in the dianhydride, and using a small amount of siloxane diamine (especially PSX). It also ensures that the glass transition temperature of the hot-melt polyimide adhesive layer is 150~200°C, and release properties (ensuring no residue is left on the leadframe when removing the tape after semiconductor packaging). This effectively prevents the back of the leadframe from being penetrated by the encapsulation resin during the packaging process. Attached Figure Description

[0017] Figures 1 to 4 A schematic diagram illustrating semiconductor packaging using the hot-melt polyimide tape of this disclosure is shown: Figure 1 The image shows the attachment of a hot melt polyimide tape (100) to one surface of a lead frame (210) by lamination technology, and the attachment of a semiconductor chip (220) to another surface of the lead frame (210); Figure 2 The wire bonding process is shown, in which a lead frame (210) is electrically connected to a semiconductor chip (220) using metal wires (230); Figure 3 The sealing process is shown, in which a sealing component (240) is used to cover and seal the upper surfaces of the lead frame (210) and the semiconductor chip (220); Figure 4 The process of removing the tape is shown to remove the hot melt polyimide tape (210) adhered to the surface of the lead frame (210). Figure 3Remove 100 from the lead frame (210). Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with embodiments. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this disclosure in any way.

[0019] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0020] Furthermore, the technical features involved in the different embodiments of this disclosure described below can be combined with each other as long as they do not conflict with each other.

[0021] This disclosure provides a hot melt polyimide adhesive layer and a hot melt polyimide tape comprising the same.

[0022] The following sections describe the hot-melt polyimide adhesive layer and the hot-melt polyimide tape in detail. It should be noted that the description of the hot-melt polyimide adhesive layer also applies to the hot-melt polyimide tape containing the hot-melt polyimide adhesive layer.

[0023] The initial bond strength between the hot-melt polyimide adhesive layer and the lead frame after the bonding process is 100 gf / cm or higher, and the bond strength between the hot-melt polyimide adhesive layer and the lead frame after the wire bonding process is 400 gf / cm or higher. The hot-melt polyimide tape comprises a substrate film and the aforementioned hot-melt polyimide adhesive layer of this disclosure.

[0024] Polyimide tapes used in semiconductor packaging processes can be categorized into high-temperature and low-temperature types based on the lamination temperature of the leadframe. This disclosure relates to a high-temperature type hot-melt polyimide tape, specifically exhibiting an initial adhesive strength of 100 gf / cm or higher, for example, 120 gf / cm or higher, 150 gf / cm or higher, or 350 gf / cm or lower, or 320 gf / cm or lower, after lamination with the leadframe (i.e., after the bonding process). In particular, the adhesive strength between the hot-melt polyimide tape of this disclosure and the leadframe after the wire bonding process is 400 gf / cm or higher, for example, 420 gf / cm or higher, 450 gf / cm or higher, or 800 gf / cm or lower, or 700 gf / cm or lower. This high adhesive strength effectively prevents the back of the leadframe from being penetrated by the encapsulating resin during the packaging process.

[0025] For the hot melt polyimide tape of this disclosure, when peeling it from the lead frame after the encapsulation process is completed, the peeling can be easily completed at an ambient temperature below the glass transition temperature (Tg) of the hot melt polyimide adhesive layer without leaving any residue.

[0026] The hot-melt polyimide adhesive layer used in this disclosure is polymerized from a monomer composition comprising an aromatic diamine monomer, an aromatic dianhydride monomer, and a siloxane diamine.

[0027] In some embodiments, the aromatic diamine is selected from p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, 2,2'-bis[4-(3-aminophenoxy)phenyl]propane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, bis(3-aminophenyl)sulfone, bis(4-aminophenyl) Sulfone, Trimethylene bis(4-aminobenzoate), 1,5-diaminonaphthalene, bis[4-(3-aminophenoxy)phenyl]sulfone, 4-(4-aminophenoxy)phenyl]sulfone, 2,5-dimethyl-1,4-phenylenediamine, 2,2'-dimethylbenzidine, 3,3'-dimethylbenzidine, 4-aminophenyl-4-aminobenzoate, 1,3-bis(3-aminophenoxy)benzene, 3,3'-dihydroxy-4,4'-diamino Biphenyl, 4,4'-diaminobenzoyl aniline, 3,5-diaminobenzoic acid, 4,4'-diamino-(1,1'-biphenyl)-2,2'-dicarboxylic acid, m-xylenediamine, 4,4'-bis(4-aminophenoxy)benzophenone, 4,4'-bis(4-aminophenoxy)biphenyl, 2,2'-bis(trifluoromethyl)benzidine, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 4,4'-diamino- One or more of 2,2'-bis(trifluoromethyl)diphenyl ether and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane; wherein, in the aromatic diamine, 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP) accounts for more than 70 mol% of the total molar percentage of the diamine monomer, for example, more than 75 mol%, more than 80 mol%, more than 85 mol%, more than 90 mol%, or even more than 100 mol%.

[0028] The following is a list of the names and CAS numbers of these aromatic diamines:

[0029] In some embodiments, the aromatic dianhydride is selected from phenyl dianhydride (PMDA, CAS 89-32-7), biphenyl dianhydride (BPDA, including s-BPDA (CAS No. 2420-87-3) and a-BPDA (CAS No. 36978-41-3)), bisphenol A type diether dianhydride (4,4'-(4,4'-isopropylphenylene diphenoxy) bisphthalic anhydride: BPADA, CAS No. 38103-06-9), hexafluoroisopropylidene dianhydride (4,4'-(hexafluoroisopropylphenylene) diphthalic anhydride: 6FDA, CAS No. 1107-00-2), 4,4'-oxodiphthalic anhydride (4,4'-oxodiphthalic anhydride: ODPA, CAS No. 1823-59-2), benzophenone tetracarboxylic dianhydride (3,3 One or more of the following aromatic dianhydrides: ',4,4'-benzophenone tetracarboxylic dianhydride (BTDA), ethylene glycol bis(4-triphenyltriatic anhydride) (TMEG, CAS No. 1732-96-3), diphenyl sulfone tetracarboxylic dianhydride (4,4'-sulfonyl diphthalic anhydride (DSDA, CAS No. 2540-99-0), and naphthalene-2,3,6,7-tetracarboxylic dianhydride (2,3,6,7-NTDA, CAS No. 81-30-1), wherein ethylene glycol bis(4-triphenyltriatic anhydride) (TMEG) accounts for more than 70 mol% of the total molar percentage of the dianhydride monomer, for example, more than 75 mol%, more than 80 mol%, more than 85 mol%, more than 90 mol%, or even more than 100 mol%.

[0030] In some embodiments, the molar ratio of total diamine monomer to total dianhydride monomer is from 1.1:0.9 to 0.9:1.1, for example, 0.9:1, 0.9:1.1, 1:1, 1.1:0.9 or any value between them.

[0031] In some embodiments, the siloxane diamine is a polydimethylsiloxane (PSX) with diamino-terminated ends having the following formula. Where R is C 1-20 Alkylene (e.g., C10) 2-10 Alkylene, such as methylene, 1,2-ethylene, 1,3-propylene, 1,4-butylene, 1,6-hexylene, etc., with n being an integer from 1 to 20. In some embodiments, the siloxane diamine is a bis(γ-aminopropyl)polydimethylsiloxane (i.e., R is 1,3-propylene) with a weight-average molecular weight (Mw) of 500 to 1200 (e.g., 500, 600, 700, 800, 900, 1000, 1100, 1200 or any value between therewith).

[0032] Preferably, the siloxane diamine accounts for 5 mol% to 20 mol% of the total molar percentage of the diamine monomer, for example, 6 mol%, 7 mol%, 8 mol%, 10 mol%, 12 mol%, 15 mol%, 18 mol%, 20 mol%, or any value between them.

[0033] By controlling the proportions of BAPP in the diamine and TMEG in the dianhydride, a small amount of siloxane diamine (especially PSX) can be used to achieve the target adhesive strength (high adhesion) and ensure that the glass transition temperature of the hot melt polyimide adhesive layer is 150~200°C, as well as release properties (ensuring no residue is left on the lead frame when removing the tape after semiconductor packaging).

[0034] The hot melt polyimide tape disclosed herein includes a substrate film and a hot melt polyimide adhesive layer disclosed herein.

[0035] In some embodiments, the substrate film is a polyimide substrate film. Preferably, the thickness of the polyimide substrate film is 5 to 100 micrometers, and / or the thickness of the hot-melt polyimide adhesive layer is 0.1 to 2 micrometers.

[0036] The following describes the preparation method of this hot melt polyimide tape, including the following steps: S1. To form a polyamic acid from a monomer composition, said monomer composition comprising an aromatic diamine monomer, an aromatic dianhydride monomer, and a siloxane diamine; S2. The polyamic acid is coated on one surface of a substrate film and cured by heat treatment to form a hot-melt polyimide adhesive layer on the substrate film.

[0037] In some implementations, S1 includes: S11. Dissolve the aromatic dianhydride and the aromatic diamine in the first organic solvent to carry out the first reaction; S12. Add a second organic solvent and siloxane diamine to the contents of the first reaction to carry out a second reaction and obtain the polyamic acid.

[0038] In some embodiments, the first organic solvent is selected from one or more of N,N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), tetrahydrofuran (THF), N,N-diethylformamide (DEF), N-ethyl-2-pyrrolidone (NEP), N,N-diethylacetamide (DEAc), and N,N-dimethylpropionamide (DMPA). Preferably, the temperature of the first reaction is 25-70°C, and / or the time of the first reaction is 4-8 hours.

[0039] In some embodiments, the second organic solvent is selected from one or more of xylene, benzene, toluene, cyclohexanone, diethylbenzene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, diethylene glycol, triethylene glycol, n-hexane, n-heptane, n-octane, n-nonane, n-decane, n-undecane, and n-dodecane. Preferably, the temperature of the second reaction is 25-70°C, and / or the time of the second reaction is 12-24 hours.

[0040] In some embodiments, the weight ratio of the first organic solvent to the second organic solvent is 5:5 to 9:1. If too much of the first organic solvent is used, the polymerization reaction may be difficult to proceed; conversely, if too little is used, gelation may occur.

[0041] Thus, in some embodiments, the solid content of the obtained polyamic acid is 5 to 25 wt%, for example, 10 wt%, 15 wt%, 20 wt%, 25 wt%, or any value between them.

[0042] The obtained polyamic acid is then coated onto the surface of the substrate film, and after heat treatment and curing, the hot melt polyimide tape that can be used directly can be obtained.

[0043] Preferably, the temperature of the heat treatment is 60~300℃, for example, 60℃, 100℃, 150℃, 200℃, 240℃, 300℃ or any value between them.

[0044] In some embodiments, the total time of the heat treatment is 10 to 180 minutes; for example, 10 minutes, 50 minutes, 100 minutes, 150 minutes, 180 minutes or any value between them.

[0045] In some embodiments, the heat treatment is a multi-stage heat treatment. The multi-stage heat treatment includes gradually increasing the temperature from 60°C to 240°C (e.g., 60°C, 80°C, 100°C, 120°C, 140°C, 160°C, 180°C, 200°C, 220°C, 240°C, or any value between them), with a treatment time of 1 to 30 minutes at each temperature. In some embodiments, the multi-stage heat treatment may include gradually increasing the temperature from 60°C to 130°C, 200°C, 220°C, 240°C, and 300°C, with a treatment time of 5 minutes at each temperature.

[0046] In some embodiments, the hot melt polyimide tape can be used for semiconductor packaging. Figures 1 to 4 A schematic diagram of semiconductor packaging using the hot melt polyimide tape of this disclosure is shown.

[0047] like Figure 1As shown, a hot-melt polyimide tape (100) is attached to a surface of a lead frame (210) using a lamination technique. For the hot-melt polyimide tape of this disclosure, the hot-melt polyimide adhesive layer is brought into contact with the back side of the lead frame and bonded to the back side of the lead frame by hot pressing at 200-250°C, 1-30 MPa, and 1-60 seconds, thereby completing the bonding process between the hot-melt polyimide tape and the lead frame. The initial adhesive strength between the hot-melt polyimide adhesive layer (i.e., the hot-melt polyimide tape) and the lead frame after the bonding process is 100 gf / cm or more, for example, 120 gf / cm or more, for example, 150 gf / cm or more, or 350 gf / cm or less, or 320 gf / cm or less.

[0048] Next, a chip mounting process is performed to attach the semiconductor chip (220) to another surface of the lead frame (210).

[0049] Next, as Figure 2 As shown, a wire bonding process is performed, using metal wires (230) to electrically connect the lead frame (210) to the semiconductor chip (220). This wire bonding process can be performed at approximately 210°C for 10 minutes. In some embodiments, the adhesion strength between the hot-melt polyimide adhesive layer (i.e., the hot-melt polyimide tape) and the lead frame after the wire bonding process is 400 gf / cm or more, for example, 420 gf / cm or more, for example, 450 gf / cm or more, or less than 800 gf / cm, or less than 700 gf / cm.

[0050] Next, as Figure 3 As shown, a sealing process is performed by covering and sealing the lead frame (210) and the upper surface of the semiconductor chip (220) with a sealing component (240). This sealing component (240) protects the semiconductor chip (220) from external environmental influences. For example, epoxy molding compound (EMC) can be used as the sealing component (240). This sealing process can be performed at a temperature of approximately 160 to 200°C. Due to the high adhesive strength (above 400 gf / cm) between the hot-melt polyimide adhesive layer (i.e., hot-melt polyimide tape) and the lead frame, epoxy resin flow can be prevented during the molding process.

[0051] Next, as Figure 4 As shown, a tape removal process is performed to remove the hot melt polyimide tape (210) adhered to the surface of the lead frame (210). Figure 3 100) is removed from the lead frame (210). For the hot melt polyimide tape of this disclosure, when peeling it from the lead frame after the encapsulation process is completed, peeling can be easily completed without leaving any residue at an ambient temperature below the glass transition temperature (Tg) of the hot melt polyimide adhesive layer.

[0052] Semiconductor packages (200) can be manufactured using the above process.

[0053] This disclosure also relates to a structure for semiconductor packaging, including a lead frame and a hot melt polyimide tape of this disclosure, wherein the hot melt polyimide tape is attached to one surface of the lead frame via a hot melt polyimide adhesive layer; The initial adhesive strength between the hot-melt polyimide adhesive layer and the lead frame after the bonding process is above 100 gf / cm, and the adhesive strength after the wire bonding process is above 400 gf / cm. This high adhesive strength effectively prevents the encapsulation resin from penetrating the back of the lead frame during the encapsulation process.

[0054] The present disclosure will be further described in detail below with reference to embodiments. Through these descriptions, the features and advantages of the present disclosure will become clearer and more apparent.

[0055] Example 1 Under a nitrogen atmosphere, TMEG and BTDA in a molar ratio of 8:2 were added to a first organic solvent (specifically dimethylacetamide (DMAc)). After dissolving by stirring at 65°C, BAPP was added, and the reaction was continued at a first reaction temperature (65°C) for 4 hours. Then, bis(γ-aminopropyl)polydimethylsiloxane (PSX) with a weight-average molecular weight of 900 (PSX to BAPP molar ratio of 1:9) and a second organic solvent (specifically xylene) were added, and the reaction was continued at a second reaction temperature (65°C) for at least 4 hours to obtain polyamic acid. The molar ratio of total dianhydride to total diamine was 1:1, and the weight ratio of the first organic solvent to the second organic solvent was 8:2. The solid content of the polyamic acid was 12 wt%.

[0056] The above-mentioned polyamic acid was coated on a 25-micrometer-thick polyimide film, and then subjected to gradient heating at 130℃, 200℃, 250℃ and 285℃ for 5 minutes respectively, to finally prepare a 1-μm-thick hot melt polyimide adhesive layer, thus obtaining hot melt polyimide tape.

[0057] Examples 2-4 and Comparative Examples 1-5 The corresponding hot-melt polyimide tapes were prepared according to the method of Example 1, following the diamine and dianhydride compositions listed in Table 1. The numbers in parentheses in Table 1 represent the number of moles of the substance in 10 parts of total diamine or total dianhydride monomers. For example, the diamine composition of Example 3 includes PSX (1), BAPP (8), and ODA (1), indicating that in 10 parts of total diamine monomers, PSX is 1 part, BAPP is 8 parts, and ODA is 1 part (in moles); the dianhydride composition includes TMEG (10), indicating that in 10 parts of total dianhydride monomers, TMEG is 10 parts (in moles), meaning that the dianhydride monomers consist only of TMEG. Other examples and comparative examples have similar meanings.

[0058] Table 1 lists the diamine and dianhydride compositions of Examples 1-4 and Comparative Examples 1-5, and Table 2 shows the test results.

[0059] Table 1 Monomer Composition

[0060] Table 2 Test Results

[0061] Test methods 1) Glass transition temperature The glass transition temperature of the hot-melt polyimide adhesive layer was measured using DMA.

[0062] 2) Adhesion strength When measuring the adhesion strength to the lead frame (SUS board), hot melt polyimide tape was cut into 30 mm (width) × 150 mm (length) pieces and then pasted onto the SUS board using a hot press (temperature: 235°C, pressure: 6 MPa, time: 10 sec), and the initial adhesion strength was measured by peeling at 90°.

[0063] The bonded sample was heat-treated using a hot plate at 180°C for 1 hour (simulating chip mounting process) and 210°C for 10 minutes (simulating wire bonding process), and then the adhesion strength after wire bonding was measured by 90° peel.

[0064] 3) Test method for residues after degumming Following the method for determining adhesive strength, hot-melt polyimide tape was bonded to the leadframe (SUS board) and heat-treated at 180°C for 1 hour (simulating chip mounting process) and 210°C for 10 minutes (simulating wire bonding process). Afterward, the hot-melt polyimide tape was removed from the leadframe, and a microscope was used to check for any residue on the leadframe surface. X indicates that there are no residues; O indicates the presence of residue.

[0065] The preferred embodiments of this disclosure have been described in detail above; however, this disclosure is not limited thereto. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in this disclosure and are all within the protection scope of this disclosure.

Claims

1. A hot-melt polyimide adhesive layer, wherein, The glass transition temperature of the hot-melt polyimide adhesive layer is 150~200℃; When the hot-melt polyimide adhesive layer is attached to the lead frame for semiconductor packaging, the initial adhesive strength with the lead frame after the bonding process is above 100 gf / cm, and the adhesive strength with the lead frame after the wire bonding process is above 400 gf / cm.

2. The hot-melt polyimide adhesive layer according to claim 1, wherein, The hot-melt polyimide adhesive layer is polymerized from a monomer composition, which includes an aromatic diamine monomer, an aromatic dianhydride monomer, and a siloxane diamine. The aromatic diamine is selected from p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, 2,2'-bis[4-(3-aminophenoxy)phenyl]propane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, bis(3-aminophenyl)sulfone, bis(4-aminophenyl)sulfone, trimethylene bis(4-aminobenzoic acid ester), 1,5-diaminonaphthalene, bis[4-(3-aminophenoxy)phenyl]sulfone, 4-(4-aminophenoxy)phenyl]sulfone, 2,5-dimethyl-1,4-phenylenediamine, 2,2'-dimethylbenzidine, 3,3'-dimethylbenzidine, 4-aminophenyl-4-aminobenzoic acid ester, 1,3-bis(3-aminophenyl ... The aromatic diamine comprises one or more of the following: 3,3'-dihydroxy-4,4'-diaminobiphenyl, 4,4'-diaminobenzoyl aniline, 3,5-diaminobenzoic acid, 4,4'-diamino-(1,1'-biphenyl)-2,2'-dicarboxylic acid, m-xylenediamine, 4,4'-bis(4-aminophenoxy)benzophenone, 4,4'-bis(4-aminophenoxy)biphenyl, 2,2'-bis(trifluoromethyl)benzidine, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 4,4'-diamino-2,2'-bis(trifluoromethyl)diphenyl ether, and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane; wherein, in the aromatic diamine, 2,2-bis[4-(4-aminophenoxy)phenyl]propane accounts for more than 70 mol% of the total molar percentage of the diamine monomer. The aromatic dianhydride is selected from one or more of the following: benzoyl tetracarboxylic dianhydride, biphenyl tetracarboxylic dianhydride, bisphenol A type diether dianhydride, hexafluoroisopropylidene dianhydride, 4,4′-oxo-bihydric dianhydride, benzophenone tetracarboxylic dianhydride, ethylene glycol bis(4-triphenyltriacyl anhydride), diphenyl sulfone tetracarboxylic dianhydride, and naphthalene-2,3,6,7-tetracarboxylic dianhydride, wherein ethylene glycol bis(4-triphenyltriacyl anhydride) accounts for more than 70 mol% of the total molar percentage of the dianhydride monomer; And / or, the molar ratio of total diamine monomer to total dianhydride monomer is 1.1:0.9 to 0.9:1.

1.

3. The hot-melt polyimide adhesive layer according to claim 2, wherein, The siloxane diamine is a polydimethylsiloxane with diamino-terminated ends having the following formula: Where R is C 1-20 Alkylene, where n is an integer from 1 to 20; preferably, R is methylene, 1,2-ethylene, 1,3-propylene, 1,4-butylene, or 1,6-hexylene; Preferably, the siloxane diamine is a bis(γ-aminopropyl)polydimethylsiloxane with a weight-average molecular weight (Mw) of 500-1200; Preferably, the siloxane diamine accounts for 5 mol% to 20 mol% of the total molar amount of the diamine monomer.

4. A hot melt polyimide tape comprising a substrate film and a hot melt polyimide adhesive layer according to any one of claims 1-3.

5. The hot-melt polyimide tape according to claim 4, wherein, The substrate film is a polyimide substrate film; Preferably, the thickness of the polyimide substrate film is 5-100 micrometers. And / or, the thickness of the hot-melt polyimide adhesive layer is 0.1~2 micrometers; Preferably, the hot melt polyimide tape is used for semiconductor packaging.

6. A method for preparing the hot-melt polyimide tape according to claim 4 or 5, comprising the following steps: S1. To form a polyamic acid from a monomer composition, said monomer composition comprising an aromatic diamine monomer, an aromatic dianhydride monomer, and a siloxane diamine; S2. The polyamic acid is coated on one surface of a substrate film and cured by heat treatment to form a hot-melt polyimide adhesive layer; Preferably, the temperature of the heat treatment is 60~300℃; and / or the total time of the heat treatment is 10~180 minutes; Preferably, the heat treatment is a multi-stage heat treatment.

7. The preparation method according to claim 6, characterized in that, S1 includes: S11. Dissolve the aromatic dianhydride and the aromatic diamine in the first organic solvent to carry out the first reaction; S12. Add a second organic solvent and siloxane diamine to the contents of the first reaction to carry out a second reaction and obtain the polyamic acid; Preferably, the temperature of the first reaction is 25~70°C, and / or the time of the first reaction is 4~8 hours; Preferably, the temperature of the second reaction is 25~70°C, and / or the time of the second reaction is 12~24 hours.

8. The preparation method according to claim 7, characterized in that, The first organic solvent is selected from one or more of N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, N,N-dimethylformamide, tetrahydrofuran, N,N-diethylformamide, N-ethyl-2-pyrrolidone, N,N-diethylacetamide, and N,N-dimethylpropionamide; And / or, the second organic solvent is selected from one or more of xylene, benzene, toluene, cyclohexanone, diethylbenzene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, diethylene glycol, triethylene glycol, n-hexane, n-heptane, n-octane, n-nonane, n-decane, n-undecane, and n-dodecane; And / or, the weight ratio of the first organic solvent to the second organic solvent is 5:5 to 9:

1.

9. The preparation method according to claim 7, characterized in that, The solid content of the polyamic acid is 5~25wt%.

10. A structure for semiconductor packaging, comprising a lead frame and a hot-melt polyimide tape as described in claim 4 or 5, or a hot-melt polyimide tape prepared by any one of claims 6-9, wherein, The hot melt polyimide tape is attached to one surface of the lead frame via a hot melt polyimide adhesive layer; The initial bonding strength between the hot-melt polyimide adhesive layer and the lead frame after the bonding process is above 100 gf / cm, and the bonding strength between the hot-melt polyimide adhesive layer and the lead frame after the lead bonding process is above 400 gf / cm.

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