JP3118961B2 - Method for manufacturing single-sided copper-clad laminate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a single-sided copper-clad laminate which is less likely to be warped by heating during processing.

[0002]

2. Description of the Related Art A single-sided copper-clad laminate uses paper such as kraft paper or linter paper as a base material, and phenol resin, melamine resin, unsaturated polyester resin or the like as a resin. As the copper foil, a copper foil with an adhesive is usually used.

[0003] In particular, a dry oil-modified phenol resin is often used as a resin in order to improve the punching workability. Phenols for phenolic resins include phenol, meta-cresol, para-cresol, ortho-cresol, isopropylphenol, para-tert-butylphenol, paraisopropenylphenol oligomer,
As drying oils such as nonylphenol and bisphenol A, paulownia oil, dehydrated castor oil, and euca deer oil are used.

[0004]

Recently, a single-sided copper-clad laminate using a paper base has been provided with a silver paste through-hole or a copper paste through-hole, and is required to have high reliability. became. Therefore, a paper base material is pretreated with a water-soluble phenol resin, a water-soluble melamine resin, or the like, and a material having a small heat shrinkage has been used.

However, both the silver paste through hole manufacturing process and the copper paste through hole manufacturing process have a heating process (usually drying at 150 ° C. for 30 minutes two or three times). Therefore, the occurrence of warpage could not be eliminated. An object of the present invention is to provide a manufacturing method for reducing the warpage of a single-sided copper-clad laminate, which is frequently subjected to heat processing in a silver paste through-hole manufacturing step, a copper paste through-hole manufacturing step, and the like.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a method for manufacturing a single-sided copper-clad laminate, comprising laminating one copper foil on a predetermined number of prepregs in which a paper base material is impregnated with a predetermined amount of resin and heating and pressing the same. The heat shrinkage of the copper foil side layer of the prepreg laminate is made larger than the heat shrinkage of the copper foil and the layer on the opposite side, and the difference in heat shrinkage in the vertical and horizontal directions is 0.005 to 0.05%.
A method for producing a single-sided copper-clad laminate.

The copper foil-side prepreg paper base material, the copper foil-side prepreg paper base material and the intermediate layer paper base material are selected so as to have different heat shrinkage properties, or the resin to be impregnated has different heat shrinkage properties. Or a combination of both to produce a prepreg having the desired heat shrink properties. Then, the heat shrinkage of the prepreg of the copper foil side layer is larger than the heat shrinkage of the prepreg of the copper foil and the opposite layer, and the difference between the heat shrinkage in the vertical direction and the heat shrinkage rate in the horizontal direction is 0.005 to 0.0.
Used in combination to be 5%. If the heat shrinkage of the copper foil side layer is greater than the heat shrinkage of the copper foil and the opposite layer in each of the vertical and horizontal directions, and the difference in each direction is greater than 0.05%, the silver paste through hole manufacturing process, copper paste through The amount of warpage during the etching process before the hole manufacturing process increases, and the time-dependent change in the warpage due to moisture absorption after the silver paste through hole manufacturing and the copper paste through hole manufacturing increases. If the difference in each direction is smaller than 0.005%, the warpage in the silver paste through-hole manufacturing process and the copper paste through-hole manufacturing process does not become small. This difference is preferably in the range of 0.01 to 0.03%.

[0008]

In general, when the heat shrinkage of the surface layer of the laminate is different from that of the back layer, the laminate is warped by heat treatment. The present invention is a method of producing a single-sided copper-clad laminate in consideration of this property so that the difference in the heat shrinkage between the copper foil side layer and the copper foil and the opposite side layer becomes small. That is, the base material is such that the heat shrinkage of the copper foil side layer (surface layer) of the laminate is larger by 0.005 to 0.05% than the heat shrinkage of the copper foil and the opposite layer (backside layer). When the resin is selected, the heat shrinkage of the copper foil due to the heat processing is smaller than that of the laminate, so that the contraction of the copper foil side layer in contact with the copper foil is suppressed, and as a result, the warpage of the laminate is reduced. Become.

[0009]

【Example】

Example 1 A kraft paper A having 85% α-cellulose, 1.4% longitudinal elongation at break and 2.6% lateral elongation at cut was pre-impregnated and dried with a water-soluble phenol resin so that the resin adhesion amount becomes 15%. Then, prepreg A was obtained by impregnating and drying a phenol resin having a tung oil modification rate of 30% so that the resin adhesion amount was 50%. A 1.6 m thick laminated plate obtained by combining and heating and pressing eight prepregs A has a heat shrinkage in the longitudinal direction of 0.025.
%, And the heat shrinkage in the transverse direction was 0.035%.

Pre-impregnated and dried with a water-soluble phenolic resin on kraft paper B having an α-cellulose of 97%, a longitudinal elongation of 1.0% and a lateral elongation of 2.0% so that the resin adhesion amount becomes 15%. Further, a phenol resin having a tung oil modification rate of 30% was impregnated and dried so that the resin adhesion amount became 50%, and prepreg B was obtained. The 1.6 mm thick laminate obtained by combining and pressing eight prepregs B had a heat shrinkage in the longitudinal direction of 0.013% and a heat shrinkage in the transverse direction of 0.015%.

Pre-impregnated and dried with water-soluble phenolic resin on kraft paper C having 90% α-cellulose, 1.2% longitudinal elongation and 2.4% lateral elongation, so that the resin adhesion amount becomes 15%. Then, prepreg C was obtained by impregnating and drying a phenol resin having a tung oil modification rate of 30% such that the resin adhesion amount was 50%. A 1.6 mm-thick laminate obtained by combining and heating and pressing eight prepregs C had a heat shrinkage in the longitudinal direction of 0.018% and a heat shrinkage in the transverse direction of 0.025%.

One prepreg A having the largest heat shrinkage is placed on the copper foil side layer, one prepreg B having the smallest heat shrinkage is placed on the copper foil opposite layer, and six prepregs C having an intermediate value are placed on the inner layer. Combine foil and heat and press to laminate.
A 6 mm single-sided copper-clad laminate was obtained. The difference in the value of the heat shrinkage between prepreg A and prepreg B is 0.012% in the longitudinal direction,
0.020% in the horizontal direction. The warp test value of this single-sided copper-clad laminate in the step of producing silver paste through holes was 1.5.
mm.

Example 2 The same kraft paper A as in Example 1 was pre-impregnated and dried with a water-soluble phenol resin to a resin adhesion amount of 15%.
The prepreg D was obtained by impregnating and drying to 0%.
The heat shrinkage in the longitudinal direction of the 1.6 mm thick laminate obtained by combining and pressing 8 prepregs D was 0.023.
% And the heat shrinkage in the transverse direction were 0.034%.

[0014] Kraft paper A is pre-impregnated and dried with a water-soluble phenol resin so that the resin adhesion amount becomes 15%, and further, a phenol resin having a tung oil modification rate of 35% is applied with a resin adhesion amount of 50%.
% To obtain prepreg E. Thickness 1.6 obtained by combining and heating and pressing 8 prepregs E
The heat shrinkage in the vertical direction of the laminate having a thickness of mm was 0.012%, and the heat shrinkage in the horizontal direction was 0.014%.

One prepreg D having the largest heat shrinkage is used as the copper foil side layer, one prepreg E having the smallest heat shrinkage is used as the copper foil side layer, and the prepreg C (intermediate value) obtained in Example 1 is used as the inner layer. Six sheets were stacked, and a copper foil with adhesive was further combined and heated and pressed to obtain a single-sided copper-clad laminate having a thickness of 1.6 mm. The difference between the values of the heat shrinkage ratios of the prepreg D and the prepreg E is 0.011% in the vertical direction and 0.020% in the horizontal direction. The warpage test value of this single-sided copper-clad laminate in the step of producing silver paste through holes was 1.6 mm.

Comparative Example A water-soluble phenol resin was preliminarily prepared on kraft paper C having 90% α-cellulose, 1.2% cut elongation in the longitudinal direction, and 2.4% cut elongation in the horizontal direction so that the resin adhesion amount became 15%. It was impregnated and dried, and was further impregnated and dried with a phenol resin having a tung oil modification rate of 30.5% so that the resin adhesion amount was 50%, to obtain a prepreg F. A 1.6 mm-thick laminate obtained by combining and heating and pressing eight prepregs F has a heat shrinkage in the longitudinal direction of 0.1 mm.
020% and the heat shrinkage in the horizontal direction were 0.025%.

The kraft paper C is pre-impregnated and dried with a water-soluble phenol resin to a resin adhesion amount of 15%.
% To obtain prepreg G. Thickness obtained by heating and pressing eight prepregs G in combination.
The 6 mm laminated plate had a heat shrinkage in the vertical direction of 0.025% and a heat shrinkage in the horizontal direction of 0.028%.

One prepreg F is placed on the copper foil side layer, one prepreg G is placed on the copper foil opposite layer, and six prepregs C obtained in Example 1 are placed on the inner layer. And a heat-pressed laminate in combination with the above to obtain a single-sided copper-clad laminate having a thickness of 1.6 mm. The prepreg F on the copper foil side and the prepreg C on the inner layer have substantially the same thermal contraction rate, and the prepreg G on the opposite side from the copper foil has the largest thermal contraction rate. The warpage test value of this single-sided copper-clad laminate in the step of producing silver paste through holes was 4.5 mm.

The method for measuring the heat shrinkage and the method for measuring the warpage are as follows.

Heat shrinkage: A 1.6 mm thick laminate obtained by laminating eight prepregs and laminating them under heat and pressure is heated to 150 ° C. at a heating rate of 5 ° C./min, then naturally cooled and heated. Measure the dimensional change before and after.

Warpage: A sample of 300 mm × 200 mm was taken as a test piece from a single-sided copper-clad laminate, silver through-hole holes were formed (by drilling), silver paste was embedded, silver paste was dried (150 ° C., 30 minutes), After sequentially performing five steps of silver jumper printing and silver jumper drying (150 ° C., 30 minutes), the maximum jump amount at four corners is measured.

[0022]

According to the present invention, since the heat shrinkage of each layer of the laminated board constituting the single-sided copper-clad laminate is reduced and equalized by the action of suppressing the copper foil, the warpage generated by the heating process in the manufacturing process. Less is.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ identification symbol FI H05K 3/38 H05K 3/38 B (58) Investigated field (Int.Cl. ⁷ , DB name) B32B 1/00-35 / 00 H05K 1/03 H05K 3/38

Claims (1)

(57) [Claims] 1. A method for producing a single-sided copper-clad laminate wherein one copper foil is laminated on a predetermined number of prepregs in which a paper base material is impregnated with a predetermined amount of resin and heated and pressurized. Characterized in that the heat shrinkage of the copper foil is larger than the heat shrinkage of the layer on the side opposite to the copper foil, and the difference in the heat shrinkage in the longitudinal and transverse directions is 0.005 to 0.05%. A method for manufacturing a laminated laminate.