JPH0632352B2 - Glass cloth processing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a glass cloth treatment method for producing a printed wiring board having excellent heat resistance and dimensional stability.

(Prior Art) (Problems to be Solved by the Invention) In the production of a printed wiring board using a glass cloth, the glass cloth is treated with an organic silane, then impregnated with a varnish such as an epoxy resin, and then heat treated. So-called prepreg in semi-cured state is manufactured by the following, and after cutting it to a predetermined size, several sheets of this are piled up and copper foil is further laminated on one side or both sides and hot press is applied to form a copper-clad laminate. Start from that.

Devices mounted with a printed wiring board are becoming higher in density and smaller in size, and along with this, improvement in performance such as heat resistance and dimensional stability of the printed wiring board has been strongly desired. It is said that the heat resistance and dimensional stability of a printed wiring board using a glass cloth depend not only on the quality of the glass cloth but also on the adhesiveness between the glass cloth and the varnish and the uniformity of the varnish impregnation. It is known that when the impregnation is insufficient, blister (interfacial peeling) and measling (peeling at the entanglement points) occur at high temperature.

It is known that the method of treating glass cloth with a silane coupling agent is effective for the uniform impregnation of the varnish and the improvement of adhesion to the glass cloth. However, satisfactory results have not yet been obtained by any of the methods, and further improvement is desired.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned drawbacks of the prior art and to provide a printed wiring board that uses glass cloth and is excellent in heat resistance and dimensional stability.

(Means for Solving Problems) As a result of intensive studies for solving such problems, the present inventors have found that low temperature plasma treatment is effective and arrived at the present invention.

That is, the present invention relates to a method for treating a glass cloth for a printed wiring board, which comprises subjecting the glass cloth to an organosilane treatment and then a low temperature plasma treatment.

The present invention will be described in detail below.

The glass cloth referred to in the present invention means E glass, C glass,
It is a woven fabric woven using long glass fibers having various glass component compositions such as S glass, and refers to various woven fabrics such as plain weave, twill weave and satin weave. The filament diameter of the long glass fiber used in the present invention is preferably several microns to several tens of microns. The glass cloth used in the present invention is obtained by subjecting a glass yarn obtained by combining a plurality of such glass long fibers to a warping step and a sizing step in the same manner as in ordinary woven fabric production, and then weaving. The number, thickness, and weight per unit area of the warp and weft of the glass cloth per unit length are Japanese Industrial Standard R3414 and American Military Standard (MI).
Any material that conforms to the L standard) can be used, but for example, the cross thickness is 20 microns to 25
It is preferably 0 microns and weighs in the range of 30 to 300 g per square meter. As the glass component, non-alkali glass E glass is desirable.

Usually, an organic binder or sizing agent necessary for weaving is attached to the glass cloth, and it cannot be used as it is as a glass cloth for a printed circuit board. Therefore, it is necessary to completely remove these organic substances. As a method for removing these organic substances, a furnace at about 600 ° C. or 350-
Examples of the method include a batch method for several tens of hours in a furnace at 400 ° C. (these are referred to as heat cleaning processing), and a wet processing method using a desizing agent.

The glass cloth from which organic substances have been removed by heat cleaning or the like is subsequently treated with a surface treatment agent containing organosilane as a main component in order to improve the adhesive force and the adhesiveness with the varnish for laminates. The organosilane used in the method of the present invention is represented by the general formula RnSiX _(4-n) . In this formula, X is any monovalent hydrolyzable group, such as a halogen atom, an alkoxy group and an acyloxy group, and n is 1 to 3. When n is 1 or 2, X's may be the same or different. R is a group having at least one carbon atom, and the hydrogen atom bonded to the carbon atom may be substituted with a reactive group such as an amino group, an epoxy group, a mercapto group and a vinyl group. The organosilane used in the present invention may be used as a mixture of two or more kinds.

As a typical organosilane represented by the above general formula,
For example, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-
Aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N
Examples include -β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane, γ- (phenylamino) propyltrimethoxysilane, phenyltrimethoxysilane and methyltrimethoxysilane.

These organic silanes are usually used as an aqueous solution or a mixed solution of an organic solvent such as alcohols, ketones, glycol ethers and water and adjusted to a concentration of about 0.01 to 5% by weight.

As a method of applying the surface treatment agent containing organosilane as a main component to the glass cloth, any known method such as a dipping method, a spraying method, or a gasification method can be adopted. In the commonly used dipping method, for example, the glass cloth is dipped in the organic silane solution at a temperature close to room temperature for several seconds, squeezed with a mangle, and then dried and cured at 80 to 180 ° C. for several minutes. To obtain a glass cloth having about 0.01 to 2% by weight.

In the method of the present invention, this organosilane-treated glass cloth is further subjected to low-temperature plasma treatment. Generally known processing conditions are adopted as the low-temperature plasma processing conditions. For example, the temperature is room temperature to hundreds of degrees, and the pressure is 0.1
The frequency is preferably several to several tens of megahertz, the output per unit area of the electrode is 0.1 to 10 kw / cm ² , and the processing time is preferably several seconds to several tens of minutes.

This low temperature plasma treatment can be performed either batchwise or continuously.

The glass cloth obtained by the method of the present invention is impregnated with varnish, dried, cured and prepreged, and then pressed to be processed into a laminated board for a printed wiring board.

(Examples) Next, the present invention will be described with reference to Examples. Each performance evaluation in the present invention was performed by the following methods.

(1) Dimensional stability It was evaluated according to JIS C-6486.

(2) Impregnating property Place the glass cloth on the glass plate with the triacetate film, measure the intensity of the transmitted light 3 minutes after placing the epoxy resin on the glass cloth, and the intensity of the transmitted light in the blank test, and calculate by the above formula. It was evaluated by the transmittance.

(3) Heat resistance After boiling the laminated plate at normal pressure, soak it in a solder bath at 260 ° C for 30 seconds, and remove the interface between the laminated plate (blister) and the entanglement point of glass cloth (measling). The boiling time at which peeling occurs is taken as the heat-resistant holding time.
The test piece is 50 mm × 50 mm.

Example 1 Glass cloth (warp G
75 1/0 1Z, weft G75 1/0 1Z; warp density 44 yarns / inch, weft yarn density 33 yarns / inch), aminosilane 0.
After soaking in a 1% by weight aqueous solution, the solution was uniformly squeezed with a mangle so that the amount of the aqueous solution was 30 parts by weight with respect to 100 parts by weight of glass cloth. Then, it was dried and cured at 150 ° C. for 2 minutes with a hot air dryer to obtain an aminosilane-treated glass cloth.

Next, this glass cloth was placed in a vacuum container having a parallel flat electrode installed therein, and was evacuated by a vacuum pump to reduce the pressure to 1.0.
A high frequency power of 13.56 MHz was applied to the electrodes from a high frequency power supply of 13.56 MHz at an output of 0.5 kw / cm ² to generate high temperature plasma for 1 minute to obtain a plasma processing cloth. Next, this low-temperature plasma-treated glass cloth was impregnated with an epoxy resin of FR-4 composition of NEMA standard to prepare a prepreg consisting of 45 parts by weight of epoxy resin and 55 parts by weight of glass cloth.
Eight prepregs were stacked and pressure-molded at 170 ° C. for 1 hour to prepare a laminated plate. Next, the heat resistance and the dimensional stability of the obtained laminated plate were measured. The results are shown in Table 1.

Comparative Example 1 A laminated plate was prepared by removing the low temperature plasma treatment step of Example 1, and the same items as in Example 1 were measured. The measurement results are shown in Table 1.

As is clear from Table 1, the glass cloth according to the present invention has a better varnish impregnation property than the conventional glass cloth, and the laminated board using this glass cloth is the laminated board using the conventional glass cloth. The heat resistance and dimensional stability are clearly improved in comparison with.

Examples 2 and 3 Laminates were obtained by treating under the same conditions as in Example 1 except that the aminosilane of Example 1 was replaced with epoxysilane (Example 2) or glycidoxysilane (Example 3).
The measurement results are shown in Table 2.

Comparative Examples 2 and 3 Laminates were obtained by treating under the same conditions as in Comparative Example 1 except that the aminosilane of Comparative Example 1 was replaced with epoxysilane (Comparative Example 2) or glycidoxysilane (Comparative Example 3).
The measurement results are shown in Table 2.

As is clear from Table 2, even if the silane coupling agent is changed, the impregnation property of the varnish is improved, and the heat resistance and dimensional stability of the laminated plate after the molding process are improved.

(Effect of the Invention) According to the method of the present invention, the impregnability of the glass cloth with the varnish is improved, so that the heat resistance and the dimensional stability of the printed wiring board are improved.

Claims (1)

[Claims] 1. A method for treating a glass cloth for a printed wiring board, which comprises subjecting the glass cloth to an organic silane treatment and then a low temperature plasma treatment.