JPH08238713A - Coppered laminated plate - Google Patents

Abstract

PURPOSE: To obtain a coppered laminated plate with excellent moisture-proofness and antisilver migration. CONSTITUTION: Forty to eighty pts.wt. of melamine resin and 10 to 24 pts.wt. of epoxy resin are blended based on 100 pts.wt. of polyvinyl butylal. In addition, a copper foil is integrated with a base layer through an adhesive layer of at most 100ppm of metal ionic concentration in the polyvinyl butylal.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a copper clad laminate.

[0002]

2. Description of the Related Art Copper-clad laminates are made by impregnating a fiber base material with a thermosetting resin and heating it to cure the thermosetting resin to the B stage. The prepregs are stacked (the number of prepregs is the thickness of the laminated board). It is determined by the thickness of the base material) and the surface (one side or both sides) of copper foil, and is heated and pressed to manufacture.

Copper-clad laminates used in consumer electrical equipment use paper base materials such as kraft paper and linter paper as the fiber base material. The paper base material may be previously treated with a phenol resin, a melamine resin or the like.

As the thermosetting resin, phenol resin,
Dry oil-modified phenol resin, epoxy resin, unsaturated polyester resin, etc. are used. Drying oil such as tung oil, polyester, polyether, and epoxidized polybutadiene are used for modification of the thermosetting resin. When flame retardancy is required, brominated epoxy resin, brominated biphenyl ether, or phosphoric acid ester may be added. A thermosetting resin varnish obtained by dissolving a thermosetting resin in a solvent such as toluene, methanol or acetone is impregnated into a fiber base material in a predetermined amount and dried to obtain a prepreg.

When a thermosetting resin such as a phenol resin which does not have good adhesion to a copper foil is used, an adhesive-coated copper foil in which an adhesive is applied to the copper foil is used.

As the adhesive, polyvinyl butyral,
A resin containing melamine resin and epoxy resin as main components is used. The ratio of polyvinyl butyral, melamine resin and epoxy resin is polyvinyl butyral 10
0 to 80 parts by weight of melamine resin,
The epoxy resin is 10 to 24 parts by weight.

When the ratio of the melamine resin increases, the solder heat resistance and the peeling strength of the copper foil decrease, and when it decreases, the tracking resistance decreases. Further, when the ratio of the epoxy resin is large, the solder heat resistance and the tracking resistance are deteriorated, and when the ratio is small, the peeling strength is deteriorated.

Polyvinyl butyral has a butyralization degree of 6
It is said that those having a degree of polymerization of 0 to 75% and a degree of polymerization of 1500 to 2500 are preferable. The melamine resins include unmodified melamine resins and alkyl etherified melamine resins obtained by alkyl etherifying these resins, methylated melamine resins,
Alkyl etherified melamine resins such as butylated melamine resins are preferably used. Epoxy resins include phenolic novolac type epoxy resins, cresol novolac type epoxy resins, resole type epoxy resins, bisphenol type epoxy resins, and other epoxy resins that are glycidyl ethers of phenols (phenolic type epoxy resins), alicyclic epoxy resins, and epoxy resins. Polybutadiene, halogenated epoxy resin, flexible epoxy resin, polyfunctional epoxy resin, etc., any epoxy resin may be used, but phenol type epoxy resin,
Alternatively, a mixture of a phenol type epoxy resin and a polyfunctional epoxy resin, or epoxidized polybutadiene,
Solder heat resistance and peeling strength are not deteriorated, which is preferable. In addition to polyvinyl butyral, melamine resin and epoxy resin, a curing agent and a curing accelerator are blended, dissolved in an organic solvent, coated on copper foil, and heated to remove volatile components. Etc. are mixed, and other substances may be mixed.

[0009]

The printed wiring board obtained by processing the copper-clad laminate thus obtained is
When a voltage is continuously applied between the two silver electrodes (silver jumper, silver through hole, etc.) formed under high temperature and high humidity conditions, a silver migration phenomenon (silver migration) occurs over time. In recent years, the trend toward lighter, thinner, shorter, and smaller electrical products requires higher density of printed circuit wiring boards, and the pitch between silver through holes is also narrowed to 2.5 mm to 2.0 mm. It is about to be put to practical use. Therefore, a short circuit is likely to occur due to the silver migration phenomenon, and in order to secure the reliability of the printed wiring board, there is an increasing demand for a copper-clad laminate having more excellent silver migration resistance.

An object of the present invention is to provide a copper-clad laminate which is less likely to cause silver migration.

[0011]

The present invention relates to 100 parts by weight of polyvinyl butyral and 40 to 50 parts of melamine resin.
A copper-clad laminate in which 80 parts by weight and 10 to 24 parts by weight of an epoxy resin are blended, and a copper foil is integrated with a base material layer through an adhesive layer having a metal ion concentration in polyvinyl butyral of 100 ppm or less. Is.

The metal ion concentration in the adhesive is 100 ppm
It is important not to exceed the range, and if it exceeds the range, the silver migration resistance becomes remarkable.

The metal ions present in the adhesive are sodium, potassium, calcium, iron and the like. Polyvinyl butyral, in the production of polyvinyl butyral,
It can be purified by making it porous by changing the precipitation process and making it easy to wash.

[0014]

When metal ions are present in the adhesive, the voltage applied causes the metal ions to be attracted to and moved to the negative potential circuit side. When the metal ions reach the negative potential side of the circuit, they are discharged, and instead, silver is ionized and moves to the circuit on the opposite potential side. The higher the humidity and the temperature, the more easily the metal ions move. However, if the amount of metal ions in the polyvinyl butyral, which is the main component of the adhesive, is small, the migration is small and the silver migration resistance is good.

[0015]

Example: Sodium ion concentration is 60 ppm, potassium ion concentration is 8 ppm, calcium ion concentration is 25
ppm of polyvinyl butyral resin is used, and the ratio of polyvinyl butyral / melamine resin / epoxy resin is 1
After applying an adhesive of 00/60/20, it was dried and cured to obtain an adhesive-coated copper foil having an adhesive thickness of 60 μm. The kraft base material is previously treated with a water-soluble phenolic resin (resin adhesion amount 16 to 24%) and impregnated with resole phenolic resin with a tung oil modification rate of 35% (total resin adhesion amount 48 to 60%).
And dried to obtain a prepreg. Eight pieces of this prepreg and copper foil with adhesive are laid on top of each other and heated and pressed to a thickness of 1.6.
A double-sided copper-clad laminate having a size of mm was obtained.

Comparative Example A polyvinyl butyral resin having a sodium ion concentration of 90 ppm, a potassium ion concentration of 5 ppm and a calcium ion concentration of 35 ppm was used, and the ratio of polyvinyl butyral / melamine resin / epoxy resin / phenol resin was 100/60/20 /. After applying the adhesive that is 80,
An adhesive-coated copper foil having an adhesive thickness of 60 μm was obtained by drying and curing. A double-sided copper-clad laminate was obtained in the same manner as in the examples below.

The resulting double-sided copper-clad laminate was examined for silver migration resistance and moisture absorption. Table 1 shows the results. The silver migration resistance test is 1.
The insulation resistance between the lines was measured after maintaining the temperature at 40 ° C. and the humidity at 90% for 1000 hours in a state where a voltage of 50 V was applied between 0 mm-spaced silver paste lines. Moreover, the moisture absorption rate is determined by the pressure cooker (121 ° C., 2127.3 h).
Pa, saturated water vapor pressure) for 8 hours, and the weight difference was calculated.

[0018]

[Table 1]

[0019]

The copper-clad laminate according to the present invention withstands the conditions of the silver migration resistance test and maintains a high insulation resistance as is clear from the results of Examples and Comparative Examples. We obtained the result of keeping moisture resistance in moisture absorption rate. In other words, the copper-clad laminate according to the present invention is excellent in silver migration resistance, electrolytic corrosion resistance, and moisture resistance.

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Claims (1)

[Claims] 1. To 100 parts by weight of polyvinyl butyral, 40 to 80 parts by weight of a melamine resin and 10 to 24 parts by weight of an epoxy resin are blended, and a metal ion concentration in polyvinyl butyral is 100 ppm or less via an adhesive layer. A copper-clad laminate made by integrating copper foil with the base material layer.