KR20020038232A - Adhesive tape - Google Patents

Abstract

PURPOSE: Provided is a heat-resistant adhesive tape for a lead-on chip, which can keep the adhesive force under the temperature condition of taping and epoxy molding and improve the size stability of a lead frame. CONSTITUTION: The heat-resistant adhesive tape is produced by spreading an adhesive layer(100) on the both sides of a heat-resistant polyimide film(200), wherein the adhesive layer(100) contains 100pts.wt. of a polyimide copolymer having a glass transition temperature of more than 200deg.C and 20-100pts.wt. of an acrylonitrile/butadiene copolymer as a binder.

Description

Heat-resistant Adhesive Tape {Adhesive tape}

The present invention relates to a heat-resistant adhesive tape, and more particularly, by applying an adhesive layer using a mixture of a polyimide copolymer having a glass transition temperature of 200 ° C. or more and an acrylonitrile / butadiene copolymer as a binder to both sides of a polyimide film and taping the tape. The present invention relates to a method for producing an adhesive tape having excellent adhesive strength and heat resistance at a temperature of time and maintaining adhesive strength even under temperature conditions during epoxy molding to improve dimensional stability of a lead frame.

Adhesive tapes used in resin encapsulated semiconductor devices include tapes for fixing lead frames, die pad fixing tapes, tape automated bonding tapes, and lead-on chip tapes. These tapes all have the high adhesion, insulation and heat resistance properties of the adhesive layer as well as are mounted in the package, so they must have semiconductor level reliability, workability at taping, and sufficient heat and adhesion to withstand the entire semiconductor assembly process. Therefore, many materials have been studied so far as a component constituting the adhesive layer.

In this case, the lead-on chip package includes a case in which the pads of the semiconductor chip to be mounted are arranged at the center of the upper surface of the semiconductor chip, and the lead occupies the lead frame because the lead of the lead frame rises above the upper surface and attaches the surface. It is small compared with the advantages of reducing the area of the package. In addition, since the bonding pad used as the power supply terminal is disposed at the center of the chip, circuits in the semiconductor chip requiring such a power supply have shorter connection lines for connecting the power supply and the length is the same as the length of the connection line for the power supply in other circuits. This is because the power supply noise is reduced and the deviation between the output data can be reduced, so it is frequently used.

Meanwhile, the development of the adhesive tape used here is also rapidly progressing. In the case of the adhesive tape for the lead-on chip, the adhesive layer is coated on both sides of the polyimide film. There is an advantage.

The process temperature of the lead-on chip package is about 100-200 ° C. higher than that of the lead frame fixing tape, so that the heat resistance is further required. An adhesive tape is obtained by applying an adhesive layer of constant thickness to a heat resistant film and then laminating a protective film thereon if necessary.

Accordingly, the present inventors are trying to develop an adhesive tape for lead-on-chip which can maintain the adhesive strength not only in the temperature condition during taping but also in the temperature condition during epoxy molding, and the binder of the adhesive layer is formed of polyimide copolymer and acrylonitrile. As a result of the use of a mixture of / butadiene copolymers, it was found that the above requirements could be satisfied to complete the present invention.

Accordingly, an object of the present invention is to provide an adhesive tape for a lead-on chip that can maintain the adhesive force not only at the temperature condition during taping but also at the temperature condition during epoxy molding.

The adhesive tape for lead-on chip of the present invention for achieving the above object is produced by applying an adhesive layer comprising a mixture of a polyimide copolymer and an acrylonitrile / butadiene copolymer as a binder on both sides of the polyimide film. It is done.

1 shows a cross section of a heat resistant adhesive tape according to the present invention.

* Description of the symbols for the main parts of the drawings *

100-Adhesive Layer 200-Heat Resistant Film

The present invention will be described in more detail as follows.

The structure of the adhesive tape obtained according to the present invention has a structure in which the heat resistant adhesive layer 100 is formed on both surfaces of the heat resistant base film 200 as shown in FIG. 1.

(1) heat resistant film (200)

As the heat resistant base film used in the present invention, polyetherimide, polyparaphenylene sulfide, polyimide, polyether ketone film and composite heat resistant base film such as epoxy resin-glass fabric, epoxy resin-polyimide-glass fabric, etc. can be used. A polyimide film can be used, and the smallest difference in the coefficient of thermal expansion with respect to the heat-resistant side or the copper alloy is preferable. Other base films have the possibility that internal lead moves sideways under processing temperature conditions of 300 ° C. or higher during lead-on-chip processing to stick or short together. The thickness of a base film is 10-150 micrometers, Preferably 25-100 micrometers is suitable.

(2) adhesive layer

The binder constituting the adhesive layer of the present invention is composed of a mixture of a polyimide copolymer having an glass transition temperature of 200 ° C. or more and an acrylonitrile / butadiene copolymer, wherein the polyimide resin has a good heat resistance and a certain adhesive strength. It is prepared by copolymerization with diamine and dianhydride, the molecular weight is 10,000 to 1,000,000, more preferably 50,000 to 500,000. If the molecular weight is less than 50,000, the pyrolysis temperature is low, and thus the heat resistance is insufficient. If the molecular weight is greater than 500,000, the adhesive may not have any adhesive force and thus cannot be used.

The polyimide resin used in the present invention should have a glass transition temperature of 200 ° C. or higher in particular. The reason is that since the process temperature of lead-on chip tape is about 300 ~ 400 ℃, the material forming the adhesive layer should have fluidity at a temperature slightly lower than the process temperature. This is because polyimide with a high glass transition temperature is used to compensate for proper adhesion. If the glass transition temperature of the polyimide is lower than 200 ° C., heat resistance may be insufficient and thus it may not be used as a material of the package.

As the acrylonitrile / butadiene rubber component of the binder constituting the adhesive layer, the content of nitrile group is preferably 5 to 50% by weight. If the content of the nitrile group is less than 5% by weight, a sticky protective film should be used. If the excess surface adhesive layer of the fluidity is reduced, the adhesive force is reduced at high temperatures. A nitrile rubber having a molecular weight of 10,000 to 500,000, preferably 50,000 to 300,000 can be used.

The acrylonitrile / butadiene rubber is preferably added in an amount of 10 to 200 parts by weight, more preferably 20 to 100 parts by weight, based on 100 parts by weight of the polyimide copolymer. If the content of acrylonitrile / butadiene rubber is less than 20 parts by weight with respect to 100 parts by weight of the polyimide copolymer, the heat resistance is high, but the adhesive strength is lowered, causing short circuit due to heat under epoxy molding conditions, resulting in a package defect. If the weight part exceeds, there is a disadvantage that the heat resistance is significantly lower.

On the other hand, the adhesive layer of the present invention may include the following additives if necessary in addition to the polyimide copolymer and acrylonitrile / butadiene.

(a) vulcanizing agent

In order to improve the self-crosslinking performance by heat of the rubber component, a vulcanizing agent may be used. Examples thereof include sulfur and dimethyl peroxide. The content is 0.01-1 weight part with respect to 100 weight part of binders, Preferably it is 0.05-0.50 weight part. If it is less than 0.05 parts by weight, the low-temperature curing effect hardly occurs, and if it is more than 0.50 parts by weight, the curing effect is no longer increased.

(b) hardener

As the curing agent, known epoxy curing agents such as 4-aminophenylsulfone, 1,1-methylimidazole and the like can be used, and the content thereof is 0.01 to 1 parts by weight, preferably 0.03 to 0.30 parts by weight based on 100 parts by weight of the binder. to be. If the content is less than 0.03 parts by weight, the curing improvement is insignificant, and if it exceeds 0.30 parts by weight, there is no further curing effect.

(c) hardening accelerator

Zinc compounds are used as crosslinking activators, and they form a complex with a vulcanizing agent to show a synergistic effect of curing. Examples of the curing accelerator may be zinc, zinc oxide, zinc sulfide, and the like, and the amount is 0.02 to 1 part by weight, preferably 0.10 to 0.50 part by weight based on 100 parts by weight of the binder. If the added amount is less than 0.10 parts by weight, there is no improvement effect of the degree of curing, and if the amount is more than 0.50 parts by weight, there is no synergistic effect and there is no meaning in terms of economy.

(d) flame retardants

In the present invention, a phosphorus-based flame retardant may be added to improve the flame retardancy of the adhesive layer. Examples of flame retardants include 9,10-dihydro-9-oxo-10-phosphaphenanthrene-10-oxide, 3-hydroxyphenyl phosphinyl propanoic acid, diphenyl-1,2-di-hydroxyethyl Phosphorus containing compounds such as phosphine oxide and the like. These addition amounts are 0.02-2 weight part with respect to 100 weight part of binders, Preferably they are 0.10-1 weight part. If the added amount is less than 0.10 parts by weight, there is no effect of improving flame retardancy, and if the amount is more than 1 part by weight, the adhesive strength is lowered and there is no advantage in terms of price.

In the present invention, no filler is added.

On the other hand, the polymerization of the polyimide used as the binder in the present invention proceeds through two steps. The first is the production of polyamic acid for condensation of diamines and acid anhydrides, and the second is the imidation of polyamic acid produced, which is a chemical imidization method using an acid catalyst for ring closure and thermal imidization at high temperatures. There is a way.

The diamine and acid anhydride used in the production of the polyamic acid are preferably mixed with an aromatic compound and an aliphatic compound, because the heat resistance from the aromatic compound and the adhesion from the aliphatic compound can be simultaneously satisfied.

The above binder and additives are dissolved in amine solvents such as dimethylformamide and methylpyrrolidone, and may be heated if necessary. The viscosity of the mixed solution is 100 to 10,000 cps, preferably 500 to 5,000 cps. The comma can be coated only within this range, and the coating condition is 10 minutes at 200 ° C. However, in this case severe curling of the film occurs, so a low temperature enough to remove the solvent is appropriate. The coating thickness of the adhesive layer obtained after drying by coating is 2-100 탆, preferably 15-50 탆.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by the Examples.

Example 1

316 ml of N-methyl-2-pyrrolidone solvent was added to a 1,000 ml three-neck stirrer while refluxing nitrogen, and the mixture was allowed to stand for 10 minutes under a nitrogen atmosphere. 0.05 mol of methylene dianiline and 0.05 mol of aminophenoxybenzene were sequentially added thereto, followed by dissolving at room temperature for 20 minutes. At this time, since the temperature of the solution rises to about 40 ° C, the temperature of the solution was dropped to about 5 ° C after 20 minutes. Again, 0.05 mole of benzophenone tetracarboxylic dianhydride and 0.05 mole of ethylene glycol tetracarboxylic dianhydride are slowly added thereto and reacted for 5 hours to stop the reaction when the viscosity of the solution becomes high to synthesize polyamic acid. It was. The viscosity of the polyamic acid thus obtained was about 2,000 cps.

A small amount of paratoluene sulfonic acid was added to the synthesized polyamic acid, and toluene was added at azeotropy, stirred at 200 ° C. for 3 hours, chemical imidization was carried out, and the solvent was removed under reduced pressure, and then precipitated with methanol and water, followed by drying. , PA 1)).

30 parts by weight of acrylonitrile / butadiene (Nipol-33, manufactured by Nippon Zeon) was added to PA 1, and a polyimide / acrylonitrile / butadiene mixed solution was added to Apical NPI (polyimide film, manufactured by Kaneka) 50 μm. The surface of the film was coated with a comma knife and cured at 200 ° C. for 10 minutes to prepare an adhesive tape having a coating thickness of 23 ± 1 μm. Then, the adhesive layer was coated on the back of the film in the same manner to prepare a polyimide adhesive tape. .

Example 2

316 ml of N-methyl-2-pyrrolidone solvent was added to a 1,000 ml three-neck stirrer while refluxing nitrogen, and the mixture was allowed to stand for 10 minutes under a nitrogen atmosphere. 0.05 mol of methylene dianiline and 0.05 mol of aminophenoxybenzene were sequentially added thereto, followed by dissolving at room temperature for 20 minutes. At this time, since the temperature of the solution rises to about 40 ° C, the temperature of the solution was dropped to about 5 ° C after 20 minutes. Again, 0.1 mole of benzophenone tetracarboxylic dianhydride was slowly added thereto and reacted for 5 hours to stop the reaction when the viscosity of the solution became high to synthesize polyamic acid. The viscosity of the polyamic acid thus obtained was about 2,000 cps.

A small amount of paratoluene sulfonic acid was added to the synthesized polyamic acid, and toluene was added at azeotropy, stirred at 200 ° C. for 3 hours, chemical imidization was carried out, and the solvent was removed under reduced pressure, and then precipitated with methanol and water, followed by drying. , PA 2).

30 parts by weight of acrylonitrile / butadiene (Nipol-33, manufactured by Nippon Zeon) was added to PA 2, and a polyimide / acrylonitrile / butadiene mixed solution was added to Apical NPI (polyimide film, manufactured by Kaneka) 50 μm. The surface of the film was coated with a comma knife and cured at 200 ° C. for 10 minutes to prepare an adhesive tape having a coating thickness of 22 ± 2 μm. Then, the adhesive layer was coated on the back of the film in the same manner to prepare a polyimide adhesive tape. .

Example 3

316 ml of N-methyl-2-pyrrolidone solvent was added to a 1,000 ml three-neck stirrer while refluxing nitrogen, and the mixture was allowed to stand for 10 minutes under a nitrogen atmosphere. 0.05 mol of methylene dianiline and 0.05 mol of aminophenoxybenzene were sequentially added thereto, followed by dissolving at room temperature for 20 minutes. At this time, the temperature of the solution rose to about 40 ° C., so that the temperature of the solution dropped to about 5 ° C. after 20 minutes. Again, 0.05 mole of benzophenone tetracarboxylic dianhydride and 0.05 mole of ethylene glycol tetracarboxylic dianhydride are slowly added thereto and reacted for 5 hours to stop the reaction when the viscosity of the solution becomes high to synthesize polyamic acid. It was. The viscosity of the polyamic acid thus obtained was about 2,000 cps.

A small amount of paratoluene sulfonic acid was added to the synthesized polyamic acid, and toluene was added at azeotropy, stirred at 200 ° C. for 3 hours, chemical imidization was carried out, and the solvent was removed under reduced pressure, and then precipitated with methanol and water, followed by drying. , PA 3).

30 parts by weight of acrylonitrile / butadiene (Nipol-33, manufactured by Nippon Zeon) was added to PA 3, and a polyimide / acrylonitrile / butadiene mixed solution was added to Apical NPI (polyimide film, manufactured by Kaneka) 50 μm. The surface of the film was coated with a comma knife and cured at 200 ° C. for 10 minutes to prepare an adhesive tape having a coating thickness of 22 ± 1 μm. Then, the adhesive layer was coated on the back of the film in the same manner to prepare a polyimide adhesive tape. .

Comparative Example 1

316 ml of N-methyl-2-pyrrolidone solvent was added to a 1,000 ml three-neck stirrer while refluxing nitrogen, and the mixture was allowed to stand for 10 minutes under a nitrogen atmosphere. To this, 0.03 mol of methylene dianiline and 0.07 mol of aminophenoxybenzene were sequentially added and dissolved at room temperature for 20 minutes. At this time, since the temperature of the solution rises to about 40 ° C, the temperature of the solution was dropped to about 5 ° C after 20 minutes. Again, 0.02 mol of benzophenone tetracarboxylic dianhydride and 0.08 mol of ethylene glycol tetracarboxylic dianhydride are slowly added thereto to react for 5 hours to stop the reaction when the viscosity of the solution becomes high to synthesize polyamic acid. It was. The viscosity of the polyamic acid thus obtained was about 2,000 cps.

A small amount of paratoluene sulfonic acid was added to the synthesized polyamic acid, and toluene was added at azeotropy, stirred at 200 ° C. for 3 hours, chemical imidization was carried out, and the solvent was removed under reduced pressure, and then precipitated with methanol and water, followed by drying. , PA 4).

30 parts by weight of acrylonitrile / butadiene (Nipol-33, manufactured by Nippon Zeon) was added to PA 4, and a polyimide / acrylonitrile / butadiene mixed solution was added to Apical NPI (polyimide film, manufactured by Kaneka) 50 μm. The surface of the film was coated with a comma knife and cured at 200 ° C. for 10 minutes to prepare an adhesive tape having a coating thickness of 23 ± 1 μm. Then, the adhesive layer was coated on the back of the film in the same manner to prepare a polyimide adhesive tape. .

Comparative Example 2

316 ml of N-methyl-2-pyrrolidone solvent was added to a 1,000 ml three-neck stirrer while refluxing nitrogen, and the mixture was allowed to stand for 10 minutes under a nitrogen atmosphere. 0.1 mol of hexamethylenediamine was added thereto and dissolved at room temperature for 20 minutes. At this time, since the temperature of the solution rises to about 40 ° C, the temperature of the solution was dropped to about 5 ° C after 20 minutes. Again, 0.05 mole of benzophenone tetracarboxylic dianhydride and 0.05 mole of ethylene glycol tetracarboxylic dianhydride are slowly added thereto and reacted for 5 hours to stop the reaction when the viscosity of the solution becomes high to synthesize polyamic acid. It was. The viscosity of the polyamic acid thus obtained was about 2,000 cps.

A small amount of paratoluene sulfonic acid was added to the synthesized polyamic acid, and toluene was added at azeotropy, stirred at 200 ° C. for 3 hours, chemical imidization was carried out, and the solvent was removed under reduced pressure, and then precipitated with methanol and water, followed by drying. , PA 5).

30 parts by weight of acrylonitrile / butadiene (Nipol-33, manufactured by Nippon Zeon) was added to PA 5, and a polyimide / acrylonitrile / butadiene mixed solution was added to Apical NPI (polyimide film, manufactured by Kaneka) 50 μm. The surface of the film was coated with a comma knife and cured at 200 ° C. for 10 minutes to prepare an adhesive tape having a coating thickness of 24 μm. Then, the adhesive layer was coated on the back of the film in the same manner to prepare a polyimide adhesive tape.

Comparative Example 3

316 ml of N-methyl-2-pyrrolidone solvent was added to a 1,000 ml three-neck stirrer while refluxing nitrogen, and the mixture was allowed to stand for 10 minutes under a nitrogen atmosphere. 0.05 mol of methylene dianiline and 0.05 mol of aminophenoxybenzene were sequentially added thereto, followed by dissolving at room temperature for 20 minutes. At this time, since the temperature of the solution rises to about 40 ° C, the temperature of the solution was dropped to about 5 ° C after 20 minutes. Again, 0.05 mole of benzophenone tetracarboxylic dianhydride and 0.05 mole of ethylene glycol tetracarboxylic dianhydride are slowly added thereto and reacted for 5 hours to stop the reaction when the viscosity of the solution becomes high to synthesize polyamic acid. It was. The viscosity of the polyamic acid thus obtained was about 2,000 cps.

A small amount of paratoluene sulfonic acid was added to the synthesized polyamic acid, and toluene was added at azeotropy, stirred at 200 ° C. for 3 hours, chemical imidization was carried out, and the solvent was removed under reduced pressure, and then precipitated with methanol and water, followed by drying. , PA 1)).

Add acrylonitrile / butadiene (Nipol-33, manufactured by Nippon Zeon) to PA 1 by 120 parts by weight, and then mix polyimide / acrylonitrile / butadiene solution with Apical NPI (polyimide film, manufactured by Kaneka) 50 μm. The surface of the film was coated with a comma knife and cured at 200 ° C. for 10 minutes to prepare an adhesive tape having a coating thickness of 23 ± 1 μm. Then, the adhesive layer was coated on the back of the film in the same manner to prepare a polyimide adhesive tape. .

Comparative Example 4

316 ml of N-methyl-2-pyrrolidone solvent was added to a 1,000 ml three-neck stirrer while refluxing nitrogen, and the mixture was allowed to stand for 10 minutes under a nitrogen atmosphere. 0.05 mol of methylene dianiline and 0.05 mol of aminophenoxybenzene were sequentially added thereto, followed by dissolving at room temperature for 20 minutes. At this time, since the temperature of the solution rises to about 40 ° C, the temperature of the solution was dropped to about 5 ° C after 20 minutes. Again, 0.05 mole of benzophenone tetracarboxylic dianhydride and 0.05 mole of ethylene glycol tetracarboxylic dianhydride are slowly added thereto and reacted for 5 hours to stop the reaction when the viscosity of the solution becomes high to synthesize polyamic acid. It was. The viscosity of the polyamic acid thus obtained was about 2,000 cps.

A small amount of paratoluene sulfonic acid was added to the synthesized polyamic acid, and toluene was added at azeotropy, stirred at 200 ° C. for 3 hours, chemical imidization was carried out, and the solvent was removed under reduced pressure, and then precipitated with methanol and water, followed by drying. , PA 1)).

After adding 10 parts by weight of acrylonitrile / butadiene (Nipol-33, manufactured by Nippon Zeon) to PA 1, a polyimide / acrylonitrile / butadiene mixed solution was added to Apical NPI (polyimide film, manufactured by Kaneka) 50 μm. The surface of the film was coated with a comma knife and cured at 200 ° C. for 10 minutes to prepare an adhesive tape having a coating thickness of 22 ± 2 μm. Then, the adhesive layer was coated on the back of the film in the same manner to prepare a polyimide adhesive tape. .

The adhesive tapes obtained according to the above Examples and Comparative Examples were evaluated by the following evaluation method, and the results are shown in Table 1 below.

(1) Adhesive characteristics

The coated adhesive tape was cut to a size of 10 mm × 10 mm, and then pressed onto 400 ° C., 0.6 atm, and 2 seconds using a hot stamping machine (HSM) on one side of a standard copper foil to prepare a sample. The peel force between the copper foil and the film adhesive layer was measured by pulling on a universal testing machine (Instron 4303, Instron Co., Ltd.) at a speed of 100 mm / min.

(2) heat resistance

The following two methods were used.

① 400 degreeC residual amount was measured by TAG (Thermogravimetric Analysis).

② SYBRON The molyne 42900 Furnace put copper-bonded samples and placed at 450 ℃, 3 minutes to observe the degree of cracking of the adhesive surface was not changed at all, there is no change, good, even a little abnormal.

(3) insulation

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

In addition, the glass transition temperature of the obtained polyimide was measured by Perkin Elmer DSC7.

Example Comparative Example One 2 3 One 2 3 4 Polyimide copolymer Polyimide No. One 2 3 4 5 One One Glass transition temperature (℃) 245 255 250 185 198 245 245 Adhesive force (g / cm) 400 ℃ 130 140 130 150 180 310 30 Heat resistance 400 ℃ residue (%) 98 97 97 95 89 87 87 Furnace test Good Good Good usually usually usually Good Insulation Current value (A) 2 × 10 ^-12 4 × 10 ^-12 3 × 10 ^-12 5 × 10 ^-11 2 × 10 ^-11 8 × 10 ^-12 4 × 10 ^-10

As described in detail above, when the adhesive layer comprising a polyimide copolymer having an glass transition temperature of 200 ° C. or more and an acrylonitrile / butadiene copolymer as binders on both sides of the polyimide film according to the present invention, at the temperature at the time of taping It is preferable as an adhesive tape for lead-on chip because it shows excellent adhesion and heat resistance and can maintain the adhesion even under the temperature condition during epoxy molding to improve the dimensional stability of the lead frame.

Claims (4)

A heat resistant adhesive tape prepared by applying an adhesive layer comprising a polyimide copolymer and an acrylonitrile / butadiene copolymer as a binder on both sides of a heat resistant film. The heat resistant adhesive tape according to claim 1, wherein the polyimide copolymer has a glass transition temperature of 200 ° C or higher. The heat-resistant adhesive tape according to claim 1, wherein the adhesive layer contains 20 to 100 parts by weight of acrylonitrile / butadiene copolymer with respect to 100 parts by weight of polyimide copolymer. The heat resistant adhesive tape according to claim 1, wherein the heat resistant film is a polyimide film.