JPH05858B2 - - Google Patents

Description

[Detailed description of the invention]

Industrial Application Fields The present invention is applicable to TAB (Tape), which is attracting attention in the semiconductor device assembly process when devices are made to have a larger number of pins, are made smaller, and are mounted at a higher density.
The present invention relates to a tape (hereinafter referred to as "TAB tape") consisting of a three-layer structure of a protective layer, an adhesive layer, and an organic insulating film used in the Automated Bonding method. Prior Art Conventionally, TAB tape is processed as follows to form a film carrier tape. 1. Drill the sprocket device hole by stamping. 2. After thermally pressing the copper foil onto the perforated tape, the adhesive is cured by heating. 3. Apply photoresist, irradiate it with ultraviolet rays, etc. through a mask, and then develop it. 4 Device hole lining, copper etching,
Remove the resist and lining, fabricate the circuit, and apply solder resist. 5 Perform tin and gold plating. After the chip is inner lead bonded to the tape produced through the above steps, the leads are cut, outer lead bonded to a printed circuit board, etc., and sealed with resin. Alternatively, after performing inner lead bonding, it is sealed with resin, and peripheral circuits are also cut, and outer lead bonding is performed. Adhesives and organic insulating films often remain in peripheral circuits and sealing resins. In such cases, as density increases, ionic impurities that affect the reliability of insulation between copper foil patterns and corrosion of Al wiring on chips become a problem. Insulation reliability and ionic impurities are mainly caused by the characteristics of the adhesive.
That is, ionic impurities occur in steps 3 to 5 when the adhesive is alkaline (for example, contains potassium ions during gold plating or resist peeling);
Acid (for example, contains chlorine ions and sulfate ions when tin plating), etching solution (contains chlorine ions)
It may occur due to exposure to other substances, or it may be contained in the adhesive itself. Furthermore, the insulation reliability is controlled by the adhesive's moisture and heat resistance, electrical resistance, the above-mentioned ionic impurities, and the like. The adhesive for TAB tape that has traditionally been used is
Although it is an epoxy-based product, it a) tends to contain ionic impurities (particularly CI ions) during processing, and b) is easily hydrolyzed by moist heat.
c) Due to properties such as low electrical resistance, insulation deterioration, including metal transfer between patterns, has become a problem. Therefore, an object of the present invention is to provide a TAB tape that does not cause the above-mentioned problems in conventional TAB tapes. Problems to be Solved by the Invention The TAB tape of the present invention includes an adhesive layer and a protective layer containing at least a polyamide resin and a phenol resin on an organic insulating film, and the average amide group equivalent of the polyamide resin is 200
to 400. FIG. 1 is a schematic cross-sectional view of the TAB tape of the present invention, in which a semi-cured adhesive layer 2 and a protective film 3 serving as a protective layer are formed on one side of an organic insulating film 1.
It has a layered structure in which these are sequentially laminated. As an organic insulating film, the thickness is 25 to 188μm,
Preferably, a heat-resistant film of 50 to 125 μm such as polyimide, polyetherimide, polyphenylene sulfide, polyether ether ketone, or a composite heat-resistant film such as epoxy resin-glass cloth or epoxy resin-polyimide-glass cloth is used. Insulating film can be used. The adhesive layer must be thermosetting and semi-cured, containing at least polyamide resin and phenolic resin, and having a thickness of 10 to 40 μm.
Preferably it consists of a layer of 15 to 30 μm. In this adhesive layer, the polyamide resin is added mainly to obtain adhesion and flexibility with the organic insulating film. Polyamide resins generally have high hygroscopicity, and as a result, their electrical resistance decreases by about 3 orders of magnitude due to moisture absorption, resulting in poor moisture resistance. is 200 to 400
By using this polyamide resin, the above-mentioned problems are eliminated. That is, the amide group equivalent
When a polyamide resin of 200 to 400 is used, the hygroscopicity of the adhesive layer is lowered, the decrease in electrical resistance due to moisture absorption can be suppressed to about one digit, and the resistance to moisture such as hydrolysis is improved. As a result, insulation deterioration can be prevented. On the contrary,
When the amide group equivalent of the polyamide resin is 400 or more, the adhesion between the copper and the adhesive layer decreases, and vice versa.
If it is less than 200, the adhesive layer has high hygroscopicity,
Hydrolyzability increases and insulation properties decrease. In addition, as a polyamide resin, the molecular weight of the hydrocarbon between the amide groups in one molecular chain is from 100 to
A wide range of 800, and a mixture of randomly arranged hydrocarbon molecules between amide groups with different molecular weights may be used. These polyamide resins are preferably used because they have adhesive properties and great flexibility despite having a large amide group equivalent. The molecular weight of polyamide resin is related to its flexibility, the thermocompression bonding between the tape and the copper foil, and the melting properties when the adhesive hardens (protrusion of the adhesive from the device hole). If it is too high, the melting temperature will be low and a problem of extrusion will occur. Moreover, if the molecular weight is too high, there will be a problem that the thermocompression bonding temperature with the copper foil will be too high. Therefore, in the present invention, molecular weight of 30,000 to
It is preferable to use a polyamide resin with a softening temperature of 100 to 180°C in the range of 150,000°C. Furthermore, molecular weight distribution is a factor that affects the melting characteristics related to adhesive extrusion from device holes, etc. If the molecular weight distribution is narrow, the viscosity decreases rapidly due to heat, and the tape and copper foil At the time of hot-pressing, the hot-pressing conditions without protrusion from the device hole become narrow, which is not preferable. Therefore, the polyamide resin used in the present invention preferably has a wide molecular weight distribution. Generally, polyamide resins have high solubility in chlorinated hydrocarbon solvents due to short chains between amide bonds, high molecular weight, etc.
Difficult to dissolve in general purpose solvents such as alcohol. However, the polyamide resin having the above-mentioned amide group equivalent and molecular weight in the present invention is soluble in general-purpose solvents such as alcohol. There is also the advantage that corrosion of wiring and metal migration phenomena are less likely to occur. Examples of the phenolic resin to be contained in the adhesive layer include known phenolic resins such as alkyl phenol resins, novolak phenol resins such as paraphenyl phenol resins, and resol phenol resins. In the present invention, these phenolic resins are preferably used in an amount of 5 to 60 parts by weight based on 100 parts by weight of the polyamide resin. In the TAB tape of the present invention, the adhesive layer may further contain a thermosetting polyvinyl paraphenol resin, an epoxy resin, and an imidazole compound. As the polyvinyl paraphenol resin, those having a polymerization degree of 25 to 200, preferably 40 to 200 can be used. The epoxy resin reacts at the molecular terminal of the polyamide resin, and easily reacts with the action of polyvinyl paraphenol or imidazole compounds, thereby improving heat resistance and chemical resistance. Epoxy resins that can be used include bisphenol A diglycidyl ether, epoxidized phenol novolak,
Examples include epoxidized cresol novolak. Examples of imidazole compounds include those that dissolve in general-purpose solvents such as methyl ethyl ketone such as 2-methylimidazole and 2-ethyl-4-methylimidazole, and those that are difficult to dissolve in general-purpose solvents such as 2-phenyl-4-benzyl-5-hydroxymethylimidazole. Examples include molten ones. In the present invention, a preferable composition of the adhesive layer is a composition containing 5 to 60 parts by weight of a phenolic resin, 9 to 88 parts by weight of an epoxy resin, and 0.03 to 10 parts by weight of an imidazole compound to 100 parts by weight of a polyamide resin. It will be done. As a protective film serving as a protective layer for the adhesive layer, a polyester film such as polyethylene terephthalate can be used. Next, a method for manufacturing the TAB tape of the present invention will be explained. Figure 2 shows the manufacturing process.
An adhesive having a predetermined composition is applied onto the protective film 3 so that the film thickness after drying falls within the above range.
At this time, in order to obtain a semi-cured state, the heating conditions require drying at 150 to 180° C. for 2 minutes. Next, the organic insulating film 1 is superimposed on the surface of the formed adhesive layer 2, and the film is heated to 1 kg/kg at 100 to 130°C.
Heat and press under conditions of cm ² or more. The obtained TAB tape is wound to obtain a tape having a width of 30 to 200 mm and a length of 30 to 300 m, for example. Examples Hereinafter, the present invention will be explained using examples. Example 1 An adhesive layer paint having the following composition was applied to a protective film made of polyethylene terephthalate film having a thickness of 38 μm, and was dried by heating at 160° C. for 2 minutes to form an adhesive layer having a thickness of 20 μm. 25% isopropyl alcohol/toluene mixed solution of polyamide resin (Macromelt 6238, amide group equivalent 220, weight average molecular weight 40000, Henkel Hakusui Co., Ltd.) 400 parts Epoxy resin (Epicote 828, Yuka Ciel Co., Ltd.) 50 parts Novolac phenol Resin (CKM2400, manufactured by Showa Kobunshi Co., Ltd.) 30 parts of 50% methyl ethyl ketone solution 0.3 parts of 1% 2-methylimidazole solution in methyl ethyl ketone Next, an organic insulating film made of polyimide film with a thickness of 50 μm was overlaid and heated at 130°C, 1 kg/
A TAB tape was produced by heating and pressing under conditions of cm ² . Next, the protective film of this TAB tape was peeled off, and a 1 ounce electrolytic copper foil (thickness: 35 to 40 μm) was bonded to the tape, followed by heat and pressure treatment at 130° C. and 1 Kg/cm ² . Thereafter, the adhesive layer was cured by successively heating at 60°C for 6 hours, 80°C for 6 hours, 120°C for 3 hours, and 150°C for 5 hours. Furthermore, a photoresist film was formed and treated on the copper foil by a conventional method, and the copper foil was etched to form a comb-shaped circuit to produce a film carrier tape. Example 2 A TAB tape and a film carrier tape were produced in the same manner as in Example 1, except that a paint having the following composition was used as the paint for the adhesive layer. Polyamide resin (DPX1175, amide group equivalent
280, weight average molecular weight 100000 (manufactured by Henkel Hakusuisha)
25% isopropyl alcohol/toluene mixed solution 400 parts Epoxy resin (Epicote 828, manufactured by Yuka Shell Co., Ltd.) 50 parts Novolac phenol resin (CKM2400, manufactured by Showa Kobunshi Co., Ltd.) in 50% methyl ethyl ketone solution
30 parts 1% methyl ethyl ketone solution of 2-methylimidazole 0.3 parts Example 3 In Example 1, except that Macromelt 6212 manufactured by Henkel Hakusuisha (amide group equivalent: 310, weight average molecular weight: 40,000) was used as the polyamide resin, TAB tape and film carrier tape were produced in the same manner. Comparative Example A TAB tape and a film carrier tape were produced in the same manner as in Example 1, except that a paint having the following composition was used as the paint for the adhesive layer. Isopropyl alcohol/water mixed solution of polyamide resin (Platabonda M1276, amide group equivalent 120, manufactured by Nippon Rilsan Co., Ltd.) 500 parts Epoxy resin (Epicote 828, manufactured by Yuka Shell Co., Ltd.) 50 parts Novolac phenol resin (CKM2400, manufactured by Showa Kobunshi Co., Ltd.) 50% methyl ethyl ketone solution
30 parts 1% 2-methylimidazole solution in methyl ethyl ketone 0.3 parts The film carrier tapes of Examples 1 to 3 and Comparative Example were subjected to the following characteristic evaluation tests. 1 Initial surface resistivity: 22℃, 0%RH (JIS
C6481) 2 Initial surface resistivity: 22℃, 65%RH (JIS
C6481) 3 Surface resistivity after treatment: at 85℃, 85%RH
Surface resistivity after 1000 hours treatment, (22℃, 0%R.
H.) 4 Moisture absorption rate of adhesive: ASTM-D-570 Moisture absorption rate after 24 hours. 5 Chlorine ion concentration: 40 Soak 10g of adhesive in Baume etching solution at 40℃ for 1 hour, then wash briefly, boil and extract with 100c.c. of pure water at 100℃, and remove chlorine ions from the extracted water. Measure concentration. 6 Adhesive strength with organic insulating film (JIS C6481). 7 Conductivity: 10g of adhesive at 121℃ with 100c.c. of pure water
Electrical conductivity of extracted water when extracted by boiling for 250 hours.

[Table] Effects of the Invention Since the TAB tape of the present invention has the above structure, it has the following advantages. (1) The adhesive has low hygroscopicity and is unlikely to contain ionic impurities during processing steps such as etching and plating. (2) The adhesive layer has low hygroscopicity and low hydrolysis, and the decrease in surface resistance due to moisture absorption is small. In addition, deterioration due to PCT etc., especially insulation deterioration, is less likely to occur than in the past, and insulation reliability between patterns is high. Therefore, the TAB tape of the present invention can be applied to high-density circuits. In addition, the TAB tape of the present invention has high insulation reliability and does not cause problems with insulation between leads, so when used to connect a chip to an external circuit, even if the number of leads increases, Tape can be left on the lead part. Therefore, when a multi-pin chip is mounted, bonding errors are less likely to occur, leads are less likely to be deformed during the transportation process, bonding process, etc., and the yield is greatly increased.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of the TAB tape of the present invention, and FIG. 2 is a manufacturing process diagram of the TAB tape of the present invention. 1...Organic insulating film, 2...Adhesive layer, 3
...protective film.

Claims (1)

[Claims] 1. An adhesive layer and a protective layer containing at least a polyamide resin and a phenol resin are provided on an organic insulating film, and the polyamide resin has an average amide group equivalent of 200 to 400. Tape for TAB. 2. The TAB tape according to claim 1, wherein the adhesive layer further contains an epoxy resin. 3. The TAB tape according to claim 1, wherein the adhesive layer contains an imidazole compound. 4. The TAB tape according to claim 1, wherein the polyamide resin has a weight average molecular weight of 30,000 to 150,000.