KR100613754B1 - Adhesive tape - Google Patents

Abstract

The present invention discloses a heat-resistant adhesive tape that can be cured at low temperatures, is not sticky at room temperature, exhibits excellent adhesion and heat resistance at a taping temperature, and maintains adhesion even at an epoxy molding temperature condition of 300 ° C. to improve dimensional stability of lead frames. do. The heat resistant adhesive tape is a heat resistant adhesive tape in which an adhesive layer and a protective layer are laminated on a heat resistant base film, wherein the adhesive layer has an acrylonitrile / butadiene copolymer having a nitrile content of 10 to 35%, a silicone epoxy, a vulcanizing agent, and a curing agent. It is composed of an accelerator and a flame retardant. Preferably, the mixing ratio of the acrylonitrile / butadiene copolymer and the silicone epoxy resin is 1: 0.5 to 2 by weight.

Adhesive Tape, Lead Frame, Semiconductor

Description

Heat-resistant Adhesive Tape {Adhesive tape}

The present invention relates to a heat-resistant adhesive tape, and more particularly, it is possible to cure at low temperatures, not sticky at room temperature, showing excellent adhesion and heat resistance at a taping temperature, and maintaining adhesion even at an epoxy molding temperature condition of 300 ° C., thereby ensuring dimensional stability of the lead frame. It relates to a heat resistant adhesive tape that can improve the.

With the recent rapid development of the semiconductor market and related technologies and the miniaturization, integration and thinning of semiconductor devices and electronic components, the use of materials for the simplification of the process or thinning of the materials themselves is made to achieve the light and small size of these devices and their components. I use it.

In addition, the field of semiconductor packaging has also shown a tendency to pitch, thin and multi-pin the internal lead pins, and thus demands more stringent requirements regarding the accuracy of the positioning of each pin.

Adhesive tapes used in resin encapsulated semiconductor devices include tapes for fixing lead frames, die pad fixing tapes, and tape automated bonding (TAB) tapes.

The double lead frame fixing tape is punched under a constant temperature, pressure and time in a lead frame maker to be bonded to the lead frame, and the semiconductor maker uses it to mount a semiconductor chip on the lead frame and then package it using an epoxy resin.

Therefore, since the adhesive tape is embedded in the semiconductor package, the adhesive tape must have general heat resistance and adhesive strength to withstand the general reliability of the semiconductor process and the operation during taping and the overall semiconductor assembly procedure.

In general, an adhesive tape for a semiconductor is made by applying an adhesive layer having a predetermined thickness on at least one side of a heat resistant film and laminating a protective layer thereon.

Examples of the conventional adhesive tapes include synthetic rubber-based resins such as polyacrylonitrile, polyacrylates, acrylonitrile butadiene copolymers alone and the like on heat resistant films such as polyimide, polyparaphenylene sulfide, and polyether imide. Although the adhesive layer was formed by mixing, these adhesive tapes had problems of poor heat resistance and adhesive strength.

Republic of Korea Patent Publication No. 93-9213 discloses a composition used as the adhesive layer is mixed with 100 to 500 parts by weight of phenol resin per 100 parts by weight of acrylonitrile / butadiene copolymer.

Korean Patent Publication No. 98-016625 discloses an acrylic resin made of a monomer consisting of acrylonitrile, an acrylate having an alkyl group of 2 to 10 carbon atoms, acrylic acid, methacrylic acid, hydroxyethyl acrylate or hydroxyethyl methacrylate. And an epoxy resin composed of a bisphenol epoxy and a cresol novolac epoxy, a curing agent, and an adhesive composition composed of a silicone resin.

In Japanese Patent Laid-Open No. 7-74213, an epoxy resin or the like has a low electric resistance due to a chlorine ion impurity, thereby reducing the gas-chlorine ion concentration to 200 ppm or less by adding polyamide resin and bismaleimide resin. A composition is disclosed.

Japanese Patent Laid-Open No. Hei 6-172524 discloses a soluble polyimide resin usable for electric and electronic components.

The present invention is to solve the above-mentioned problems in the prior art, the object of the present invention is to provide a heat-resistant adhesive tape for electronic components that is excellent in low-temperature curing properties and can maintain the adhesive force at the temperature conditions during taping as well as the temperature conditions during epoxy molding. To provide.

Adhesive tape for achieving the object of the present invention is coated on at least one side of the heat-resistant base film of the adhesive layer consisting of silicon epoxy, acrylonitrile / butadiene copolymer, vulcanizing agent, curing accelerator, flame retardant, etc. It is laminated, and exhibits high adhesion and heat resistance at room temperature and taping temperature, and maintains high adhesion even at high temperature conditions (300 ° C.) after epoxy molding.

The heat resistant base film used in the present invention includes a film made of polyetherimide, polyparaphenylene sulfide, polyimide, polyether ketone, and the like, and a composite film such as epoxy resin-glass fabric and epoxy resin-polyimide-glass fabric. Although it can be used, it is preferable to use a polyimide film having the smallest difference in thermal expansion coefficient or thermal expansion coefficient with the copper alloy. It is suitable that this base film is 10-150 micrometers in thickness normally, Preferably it is 25-100 micrometers.

The adhesive layer of the present invention is obtained by coating an adhesive composition composed of silicone epoxy and acrylonitrile / butadiene copolymer.

The mixture of the silicone epoxy and the acrylonitrile / butadiene copolymer is a binder, and the silicone epoxy is an epoxy resin having a siloxane structure at its end, and has a molecular weight of 20,000 to 1,000,000, preferably 100,000 to 500,000. When the molecular weight of the silicone epoxy is 100,000 or less, the heat resistance is inferior, and when it is 500,000 or more, the compatibility and fluidity with the acrylonatril / butadiene copolymer tends to be inferior.

The acrylonitrile / butadiene copolymer has a content of nitrile group of 5 to 50% by weight, preferably 10 to 35% by weight. If the nitrile group content is 10% by weight or less, the reactivity is insufficient, and curing is insufficient. If the content is 35% by weight or more, the fluidity of the adhesive layer decreases, resulting in poor adhesion at high temperatures. In addition, the acrylonitrile / butadiene copolymer may use a nitrile rubber having a molecular weight of 10,000 to 500,000, preferably 50,000 to 300000.

The mixing ratio of the two components of the binder is 10 to 800 parts by weight of silicone epoxy resin, preferably 50 to 200 parts by weight, per 100 parts by weight of acrylonitrile / butadiene. When the epoxy resin is mixed at 50 parts by weight or less, the adhesive strength is high, but the heat resistance is deteriorated, resulting in decomposition due to heat under the epoxy molding condition, which may cause the failure of the package. do.

The adhesive composition may be used by adding a vulcanizing agent, a curing accelerator, a flame retardant, etc. if necessary in addition to the silicone epoxy and acrylonitrile / butadiene copolymer.

The vulcanizing agent is used to improve the self-crosslinking performance of the rubber component by heat, such as sulfur, dimethyl peroxide and the like. The usage-amount is 0.01-1 weight part, Preferably it is 0.05-0.50 weight part. If the added amount of the vulcanizing agent is 0.05 parts by weight or less, the low-temperature curing effect hardly occurs, and if it is 0.50 parts by weight or more, the curing effect does not improve any more.

The curing accelerator is a composite with a vulcanizing agent to bring a curing synergistic effect, which can be used as a zinc compound. Specifically, zinc (Zinc), zinc oxide (Zinc oxide), zinc sulfate (Zinc sulfate) and the like are used in an amount of 0.02 to 1 parts by weight, preferably 0.10 to 0.50 parts by weight. If the amount of the zinc compound added is 0.10 parts by weight or less, there is no improvement effect of the degree of curing, and if it is 0.50 parts by weight or more, there is no further synergistic effect.

The flame retardant is to improve the flame retardancy of the adhesive layer is usually used by adding a phosphorus flame retardant. These include 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 3-hydroxyphenyl phosphinyl propanoyl acid, diphenyl-1,2-di-hydroxyethylphosphine oxide Etc. The amount of the flame retardant added is 0.02 to 2 parts by weight, preferably 0.10 to 1 part by weight, and when the amount is 0.10 parts by weight or less, there is no effect of improving flame retardancy.

In the adhesive composition, the binder and the additives are dissolved in a solvent such as methyl ethyl ketone, toluene, cyclohexane, and then preliminarily cured at 90 ° C. for about 1 hour to improve low temperature curability, thereby forming an adhesive layer by coating. Here, the binder, the additive, the mixed solution of the solvent is good to have a viscosity capable of comma coating, the range is 100 ~ 10,000cps, preferably 500 ~ 5,000cps. The coating thickness of an adhesive layer is 2-50 micrometers, Preferably it is 10-25 micrometers.

The protective layer is provided to be convenient for use in a later process, and polyethylene, polypropylene, polyethylene terephthalate, a fluororesin film, and the like are used. In the case of stickyness, the peeling property may be imparted with a release film using a silicone resin. In this case, however, there should be no transfer of silicon to the adhesive layer. The proper thickness of the protective layer is 1 ~ 200㎛, preferably 12 ~ 50㎛.

Hereinafter, the heat-resistant adhesive tape according to the present invention will be described in more detail with reference to Examples.

Example 1

20 g of Nipol-34 (Nippon Zeon) having a nitrile content of 27% and 20 g of epoxy silicone (Tego, EW Silikoftal, 80% solids) were dissolved in 80 g of methyl ethyl ketone (MEK), followed by sulfur 0.5 g, 0.5 g of zinc oxide, and 1 g of 3-hydroxyphenyl phosphinyl propanoic acid are added. The mixed solution is stirred at 90 ° C. for 1 hour and then left to stand at room temperature for 3 hours. The left solution was coated on one surface of a 50 μm-thick polyimide film (Apical NPI, manufactured by Kaneka) using a comma knife to cure at 140 ° C. for 3 minutes to form an adhesive layer with a coating thickness of 18 ± 3 μm. Thereafter, a heat-resistant adhesive tape was laminated on an untreated PET film having a thickness of 38 μm (KOLON FD01).

Example 2

20 g of Nipol-33 (made by Nipon Zeon) with a nitrile content of 33% and 25 g of epoxy silicone (EW Silikoftal, 80% solids) made by Tego were dissolved in 80 g of MEK, followed by 0.5 g of sulfur and 0.5 g of zinc oxide, 3 Add 1 g of hydroxyphenyl phosphinyl propanoic acid. The mixed solution is stirred at 90 ° C. for 1 hour and then left to stand at room temperature for 3 hours. The left solution was coated with a comma knife on one surface of a 50 μm thick polyimide film (Apical NPI, manufactured by Kaneka), and cured at 140 ° C. for 3 minutes to form an adhesive layer having a coating thickness of 19 ± 1 μm. An adhesive tape was prepared by laminating a 38-micrometer-thick PET film (KOLON FD01).

Comparative Example 1

40 g of Nipol-20 (manufactured by Nippon Zeon) with a nitrile content of 41% and 20 g of epoxy silicone (EW Silikoftal, 80% solids) by Tego were dissolved in 80 g of MEK, followed by 0.5 g of sulfur and 0.5 g of zinc oxide, 3 Add 1 g of hydroxyphenyl phosphinyl propanoic acid. The mixed solution is stirred at 90 ° C. for 1 hour and then left to stand at room temperature for 3 hours . The left solution was coated with a comma knife on one surface of a 50 μm-thick polyimide film (Apical NPI, manufactured by Kaneka), and cured at 140 ° C. for 3 minutes to form an adhesive layer having a coating thickness of 19 ± 2 μm. An adhesive tape was prepared by laminating on a 38 μm PET film (KOLON FD01).

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Comparative Example 2

20 g of Nipol-34 (from Nippon Zeon) and 60 g of epoxy silicone (EW Silikoftal, 80% solids) of 27% nitrile group was dissolved in 80 g of MEK, followed by 0.5 g of sulfur and 0.5 g of zinc oxide, 3 Add 1 g of hydroxyphenyl phosphinyl propanoic acid. The mixed solution is stirred at 90 ° C. for 1 hour and then left to stand at room temperature for 3 hours . The left solution was coated with a comma knife on one surface of a 50 μm-thick polyimide film (Apical NPI, manufactured by Kaneka), and cured at 140 ° C. for 3 minutes to form an adhesive layer having a coating thickness of 18 ± 3 μm. An adhesive tape was prepared by laminating a 38 μm-thick PET film (KOLON FD01).

Comparative Example 3

20 g of Nipol-34 (made by Nippon Zeon) having a nitrile content of 27% and 20 g of epoxy silicone (EW Silikoftal made by Tego, 80% solids) were dissolved in MEK80 g, and stirred at 90 ° C. for 1 hour, followed by 3 at room temperature. Leave time. The left solution was coated on one surface of polyimide film (Apical NPI, manufactured by Kaneka Co., Ltd.) with a thickness of 50 μm, and cured at 140 ° C. for 3 minutes to form an adhesive layer having a coating thickness of 18 ± 3 μm. The adhesive tape was laminated to the film (KOLON FD01).

The adhesive strength, heat resistance, and insulation properties of the adhesive tapes prepared in Examples and Comparative Examples were evaluated by the following methods, and the results are shown in Table 1 below.

Adhesion

Each adhesive tape is cut into 10mm × 100mm size and pressed on one side of standard copper foil using HSM (Hot Stamping Machine) for 0.4 seconds at pressure of 4atm at 120 ℃, 180 ℃, 200 ℃ and 300 ℃, respectively. A sample was prepared, and the peel force between the copper foil and the adhesive layer of the film was measured by pulling on a universal testing machine (Instron 4303, manufactured by Instron) at a speed of 100 mm / min.

Heat resistance

The residual amount of 300 ° C. was measured by TGA (Thermogravimeteric Analysis), and a copper foil-bonded sample was placed in a furnace (SYBRON Themolyne 47900 Furnace) and left at 300 ° C. for 3 minutes, and then evaluated by observing the degree of cracking of the adhesive surface. If there is no change at all, it is good, and if there is any abnormality, it is usually displayed as a defect if the degree of burnt of the adhesive layer is severe.

Insulation

Each adhesive tape was allowed to stand for 24 hours at 24 ° C. and 45% RH under constant temperature and humidity conditions, and the amount of current was measured by applying a voltage of 100 V with a predetermined device (High Current Measurement Unit Keithley 238).

Table 1. Evaluation Properties

Example Comparative example One 2 One 2 3 4 Adhesive force (g / cm) 120 ℃ 80 70 22 24 7 66 200 ℃ 250 265 212 231 90 251 300 ℃ 280 290 190 155 77 261 Heat resistance Remaining amount (%) 98 98 93 94 94 91 Test Good Good usually usually usually usually Insulation Current value (A) 2 × 10 ^-12 3 × 10 ^-12 5 × 10 ^-11 2 × 10 ^-11 8 × 10 ^-12 4 × 10 ^-10

Referring to Table 1, the adhesive tape of the Example was superior to the adhesive tape of the comparative example under each temperature condition, and also excellent in heat resistance and insulation. These results show that the nitrile group content of the adhesive layer is closely related to the physical properties.

As described in detail above, the heat-resistant adhesive tape according to the present invention can be cured at low temperatures, exhibit excellent adhesion and heat resistance at the taping temperature, and maintain adhesion even at an epoxy molding temperature condition of 300 ° C. to improve the dimensional stability of the lead frame. Has the effect.

Claims (4)

A heat resistant adhesive tape in which an adhesive layer and a protective layer are laminated on a heat resistant base film, The adhesive layer is 50 to 200 parts by weight of silicone epoxy resin, 0.05 to 0.5 parts by weight of vulcanizing agent, 0.1 to 0.5 parts by weight of curing accelerator, based on 100 parts by weight of acrylonitrile / butadiene copolymer having a nitrile group content of 10 to 35% by weight, and Heat-resistant adhesive tape, characterized in that the composition is composed of flame retardant 0.1 to 1 parts by weight. The heat resistant adhesive tape according to claim 1, wherein the adhesive layer has a thickness of 10 to 25 µm. delete The heat-resistant adhesive tape according to claim 1, wherein the adhesive layer has a mixing ratio of acrylonitrile / butadiene copolymer and silicone epoxy resin in a weight ratio of 1: 0.5 to 2.