JP2988280B2 - Manufacturing method of 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 copper-clad laminate used as a material for printed wiring boards and the like used in electric and electronic equipment.

[0002]

2. Description of the Related Art It is known to manufacture a copper-clad laminate using an impregnated product obtained by impregnating a glass substrate with a resin varnish containing a radical polymerization type thermosetting resin. In this case, a plurality of impregnated products in which a resin varnish is impregnated into a glass substrate are stacked, copper foils are arranged above and below, and then the above-mentioned radical polymerization type thermosetting resin is cross-linked and cured to produce a copper-clad laminate. Is common. And, according to the manufacturing method using this radical polymerization type thermosetting resin, it is possible to continuously perform the process from the step of impregnating the glass substrate with the resin varnish to the step of integrating the impregnated product and the copper foil. Therefore, there are many advantages such that the long glass substrate and the long copper foil can be integrated without cutting, and can be manufactured with reduced loss. And, as shown in Japanese Patent Publication No. 5-29548, if a resin containing a vinyl ester is used as the above-mentioned radical polymerization type thermosetting resin, heat resistance, water resistance, electric characteristics, punching workability, and the like can be improved. It is known that excellent copper-clad laminates can be manufactured.

However, a copper-clad laminate has a core material made of a glass nonwoven fabric impregnated with a resin varnish containing a radical polymerization type thermosetting resin and an inorganic filler, and has a radical polymerization type thermosetting resin on both outer surfaces. A resin cloth containing resin varnish impregnated into glass cloth is laminated as a surface layer material, and then a copper foil is laminated on at least one surface thereof, and then heat-cured and integrated to form a copper-clad laminate. When the board is processed into a printed wiring board, there is a problem that warpage is likely to occur.

[0004]

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention provides a core material comprising a glass nonwoven fabric impregnated with a resin varnish containing a radically polymerizable thermosetting resin and an inorganic filler in a nonwoven fabric. A resin varnish containing a radical polymerization type thermosetting resin is impregnated into a glass cloth, and an impregnated product is laminated as a surface layer material, and a copper foil is further laminated on at least one surface thereof, and then heat-cured to form an integrated copper clad. An object of the present invention is to provide a method for manufacturing a copper-clad laminate, which can reduce warpage during processing of the laminate.

[0005]

According to a first aspect of the present invention, there is provided a method of manufacturing a copper-clad laminate, comprising the steps of: impregnating a glass nonwoven fabric with a resin varnish containing a radical polymerization type thermosetting resin and an inorganic filler in a core. A material impregnated with a glass cloth impregnated with a resin varnish containing a radical polymerization type thermosetting resin on both outer surfaces is laminated as a surface layer material, and a copper foil is laminated on at least one surface thereof, and then heated and cured. In the method for producing a copper-clad laminate, the ratio of the viscosity (η _B ) of the resin varnish used for the core material to the viscosity (η _A ) of the resin varnish used for the surface material is η _B / η _A > 5. It is characterized by.

The present inventors have studied the causes of warpage and found that one of the causes is that the composition of the resin component in the thickness direction of the laminate is non-uniform depending on the measurement position. I found it. The reason why the composition of the resin component becomes non-uniform depending on the position is considered to be that the resin varnish impregnated in the glass base material largely flows in the laminating step and the step of heating and curing, and means for preventing the resin varnish from flowing. Have been studied, and the present invention has been completed. Hereinafter, the present invention will be described in detail.

The radical polymerization type thermosetting resin used in the present invention is not particularly limited, but examples thereof include a vinyl ester resin and an unsaturated polyester resin. In addition, the resin varnish of the present invention may contain a radical polymerizable monomer such as styrene, diallyl phthalate, and methacrylic acid, and an addition type thermosetting resin such as an epoxy resin, together with the radical polymerizable thermosetting resin. It is.
Furthermore, the resin varnish used for the core material contains an inorganic filler for stabilizing the dimensional change behavior. Examples of the inorganic filler include, but are not particularly limited to, aluminum hydroxide, talc, Glass powder and the like can be exemplified. Furthermore, various additives, for example, a curing catalyst, a flame retardant, an inorganic filler, a coupling agent, and the like may be added to the resin varnish used for the core material or the surface layer material in the present invention, if necessary. Absent.

[0008] The glass nonwoven fabric and glass cloth used in the present invention are not particularly limited as long as they have insulating properties usable for electric applications. The glass nonwoven fabric naturally refers to a cloth obtained without being woven, and may be expressed as a glass paper, a glass mat, or the like.

In the method for producing a copper-clad laminate according to the first aspect of the present invention, by controlling the viscosity of the resin varnish, excessive flow of the resin varnish in the laminating step or the heat curing step is prevented. That is, it is important that the ratio of the viscosity (η _B ) of the resin varnish used for the core material to the viscosity (η _A ) of the resin varnish used for the surface layer material be η _B / η _A > 5. If η _B / η _A > 10, it is more preferable to prevent excessive flow of the resin varnish.
The temperature at which the viscosity of the varnish is measured is 30 ° C. in the present invention.
It is. When η _B / η _A ≦ 5, the resin varnish used for the core material and the resin varnish used for the surface material are mixed unevenly in the thickness direction in the laminating step and the heat curing step,
As a result, a phenomenon occurs in which the configuration of the resin component in the thickness direction differs depending on the position. The viscosity of the resin varnish is adjusted according to the type and molecular weight of the resin used, the type and amount of the radical polymerizable monomer and various additives, and the balance with the characteristics required for the laminate. You. The absolute value of the viscosity of the resin varnish is not particularly limited, but if it is too high, the impregnation of the resin varnish into the glass nonwoven fabric or glass cloth becomes insufficient, and the operation is usually performed up to 10,000 cps to impair the properties of the laminate. Is preferred.

[0010] It should be noted that a reference
In the method for producing a copper-clad laminate, a resin varnish impregnated in a glass substrate is irradiated with ultraviolet rays and precured to prevent excessive flow of the resin varnish. Usable ultraviolet irradiation devices include ordinary high-pressure mercury lamps, ultra-high-pressure mercury lamps, mercury / metal halide lamps, xenon lamps, and carbon arc lamps. On the other hand, as a resin varnish, it is not essential, but if a photopolymerization catalyst is added to the resin varnish and used, the object can be achieved with a short pre-curing, which is convenient. As a photopolymerization catalyst, use any carbonyl compound such as benzoin ether, benzophenone, acetophenone, or sulfide, quinone, azo, or sulfochloride, as long as it generates radicals in the near ultraviolet region. it can. The degree of precuring is preferably such that the surface of the impregnated article irradiated with ultraviolet rays slightly maintains fluidity. If the precuring is excessive, the adhesion between impregnated products or between the impregnated product and the copper foil is reduced. The degree of the pre-curing is adjusted according to the intensity of the ultraviolet rays to be irradiated, the type and amount of the photopolymerization catalyst, and the like. The stage of performing the pre-curing is after the impregnation step of impregnating the glass substrate with the resin varnish, the impregnated product may be laminated, and the copper foil may be further arranged and laminated. When the flow of the resin varnish generated during the product laminating step is large, it is preferable to perform the step immediately after the impregnation step. In addition, any of the following methods may be employed. Ultraviolet irradiation is applied to only the surface layer material and precured. Precuring is performed by irradiating only the core material with ultraviolet rays. The surface material and the core material are irradiated with ultraviolet rays and precured. The laminate of the core material and the surface material is irradiated with ultraviolet rays and precured.

In the reference method for producing a copper-clad laminate, the ratio of the viscosity (η _B ) of the resin varnish used for the core material to the viscosity (η _A ) of the resin varnish used for the surface material is set forth in the claims. It is not necessary to meet the special restrictions as in item 1.

[0012]

According to the present invention, the viscosity (η _B ) of the resin varnish used for the core material and the viscosity (η _B ) of the resin varnish used for the surface material are determined.
_By setting the ratio of _A ) to η _B / η _A > 5, excessive flow of the resin varnish in the laminating step and / or the heating step is prevented, and the thickness of the integrated copper-clad laminate in the thickness direction is prevented. This prevents the phenomenon that the composition of the resin component differs depending on the position.

[0013]

The present invention will be described below based on examples and comparative examples.

Raw materials were mixed as shown in Table 1 and sufficiently stirred with a disper to prepare a resin varnish. The details of the raw materials shown in Table 1 are as follows.

As the vinyl ester resin, S510 manufactured by Showa Polymer Co., Ltd. is used. As aluminum hydroxide which is a kind of inorganic filler, Sumitomo Chemical Co., Ltd. is used.
Manufactured by Takehara Kagaku Kogyo Co., Ltd. was used as the kaolin clay as a kind of inorganic filler. In addition, cumene hydroperoxide (hereinafter abbreviated as CHP) was used as a thermal polymerization catalyst, and Irgacure I-651 (trade name as I-651) manufactured by Ciba Geigy was used as a photopolymerization catalyst. A 1 KW ultra-high pressure mercury lamp was used for ultraviolet irradiation.

Example 1 The resin varnish A1 shown in Table 1 was applied to a plain woven glass cloth (size 300 mm × 300 mm) having a thickness of 200 μm, and the resin varnish B1 described in the same table was applied to a glass nonwoven fabric having a thickness of 370 μm (size (300 mm x 300 mm) to obtain impregnated products. Three pieces of the impregnated glass non-woven fabric base material are stacked to form a core material, and one piece of the impregnated glass cloth base material is laminated as a surface material above and below the core material. The 18 μm-thick copper foil was passed between two rolls prepared at a predetermined gap. Next, the obtained laminate was sandwiched between two metal plates, and was heated and cured at 110 ° C. for 60 minutes in a flat state to produce a copper-clad laminate having a thickness of 1.6 mm. In addition, as is clear from the viscosity of the resin varnish shown in Table 1,
In this embodiment, the ratio of the viscosity (η _B1 ) of the resin varnish B1 used for the core material to the viscosity (η _A1 ) of the resin varnish A1 used for the surface material was about 17.

Example 2 The procedure of Example 1 was repeated, except that the resin varnish B2 shown in Table 1 was used instead of the resin varnish B1, and the thickness was 1.6 mm.
Was produced. As is apparent from the viscosity of the resin varnish shown in Table 1, the viscosity (η _B2 ) of the resin varnish B2 used for the core material in the present embodiment and the viscosity (η _B ) of the resin varnish A1 used for the surface material were used. _A1 ) ratio was 7.3.

Comparative Example 1 The procedure of Example 1 was repeated, except that the resin varnish B3 shown in Table 1 was used instead of the resin varnish B1, and the thickness was 1.6 mm.
Was produced. As is clear from the viscosity of the resin varnish shown in Table 1, the viscosity (η _B3 ) of the resin varnish B3 used for the core material in the present embodiment and the viscosity (η _B ) of the resin varnish A1 used for the surface layer material were used. The ratio of _A1 ) was 4.3.

Reference Example 1 A resin varnish A2 shown in Table 1 was impregnated into a 200 μm-thick plain woven glass cloth (300 mm × 300 mm), and then impregnated with ultraviolet rays for 60 seconds from a distance of about 10 cm from the impregnated article. Irradiate one surface of
A precured impregnated product was obtained. Further, a resin varnish B4 shown in Table 1 was coated with a 370 μm thick glass nonwoven fabric (size 30).
(0 mm x 300 mm) to obtain an impregnated product. A core material is formed by stacking three impregnated products of the obtained glass nonwoven fabric base material,
One piece of the pre-cured glass cloth substrate impregnated product was laminated as a surface material on the upper and lower sides, and further, 18 μm-thick copper foils were respectively disposed on the upper and lower surfaces of the laminate to prepare a predetermined gap. It passed between two rolls. Next, the obtained laminate was sandwiched between two metal plates, and was heated and cured at 110 ° C. for 60 minutes in a flat state to produce a copper-clad laminate having a thickness of 1.6 mm.

( Reference Example 2 ) Three sheets of a glass woven fabric (size 300 mm x 300 mm) impregnated with a resin varnish B4 shown in Table 1 and having a thickness of 370 µm were superposed on each other. Precuring was performed by irradiating both surfaces of the laminate with ultraviolet light for 45 seconds from a distance of 10 cm away to obtain a precured laminate. In addition, resin varnish A2 shown in Table 1
To a 200μm thick plain weave glass cloth (size 300
mm × 300 mm) to obtain an impregnated product. A laminate obtained by laminating and impregnating the three impregnated products of the glass nonwoven fabric substrate obtained above as a core material, and laminating one each of the impregnated product of the glass cloth substrate as a surface material above and below the core material, An 18 μm-thick copper foil disposed on the upper and lower surfaces of the laminate was passed between two rolls prepared at a predetermined gap. Next, the obtained laminate was sandwiched between two metal plates, and was heated and cured at 110 ° C. for 60 minutes in a flat state to produce a copper-clad laminate having a thickness of 1.6 mm.

Reference Example 3 A resin varnish A2 shown in Table 1 was impregnated into a 200 μm-thick plain woven glass cloth (300 mm × 300 mm), and then impregnated with ultraviolet rays from a distance of about 10 cm from the impregnated product for 60 seconds. Irradiate one surface of
A precured impregnated product was obtained. Further, a resin varnish B4 shown in Table 1 was coated with a 370 μm-thick glass nonwoven fabric (size 30).
(0 mm × 300 mm), and then impregnated into three layers.
Precuring was performed by irradiating ultraviolet rays to both sides of the laminate for 45 seconds from a distance m apart to obtain a precured laminate. A laminate obtained by laminating and impregnating the three impregnated products of the obtained glass nonwoven fabric base material was used as a core material, and one layer of the impregnated product of the precured glass cloth base material was laminated as a surface material above and below the core material. An 18 μm-thick copper foil disposed on the upper and lower surfaces of the laminate was passed between two rolls prepared at a predetermined gap. Next, the obtained laminate is sandwiched between two metal plates, and is cured by heating at 110 ° C. for 60 minutes in a flat state, and has a thickness of 1.6 mm.
Was produced.

REFERENCE EXAMPLE 4 A resin varnish A2 shown in Table 1 was impregnated into a 200 μm-thick plain-woven glass cloth (300 mm × 300 mm) to obtain an impregnated product. Further, a resin varnish B4 shown in Table 1 was coated with a 370 μm thick glass nonwoven fabric (300 mm × 30 mm in size).
0 mm) to obtain an impregnated product. Next, three pieces of the impregnated product of the obtained glass nonwoven fabric base material are laminated as a core material, and one piece of each of the impregnated products of the glass cloth base material is laminated as a surface material above and below the core material. About 1 each from both surfaces
Precuring was performed by irradiating both surfaces of the laminate with ultraviolet rays for 45 seconds from a distance of 0 cm, to obtain a precured laminate. Further, a copper foil having a thickness of 18 μm disposed on the upper and lower surfaces of the laminate was passed between two rolls prepared at a predetermined gap. Then, the obtained laminate was
Sandwiched between two metal plates, 110
It was cured by heating at 60 ° C. for 60 minutes to produce a copper-clad laminate having a thickness of 1.6 mm.

Comparative Example 2 A plain woven glass cloth (size 300 mm × 300 mm) having a thickness of 200 μm was impregnated with the resin varnish A2 shown in Table 1 to obtain an impregnated product. Further, a resin varnish B4 shown in Table 1 was coated with a 370 μm thick glass nonwoven fabric (300 mm × 30 mm in size).
0 mm) to obtain an impregnated product. Three pieces of the impregnated product of the glass nonwoven fabric base material are laminated to form a core material, and one piece of the above impregnated product of the glass cloth base material is laminated as a surface material above and below the core material. Each having 18 μm-thick copper foil was passed between two rolls prepared at a predetermined gap. Next, the obtained laminate was sandwiched between two metal plates, and was heated and cured at 110 ° C. for 60 minutes in a flat state to produce a copper-clad laminate having a thickness of 1.6 mm.

The copper clad laminate obtained in each of the above Examples , Reference Examples and Comparative Examples was cut into 250 mm × 250 mm, and the entire surface was etched to remove the copper foil.
Put it in a state where it is suspended in an oven heated to 0 ° C.
Heat treatment was carried out for 0 minutes, and then the suspension was taken out and cooled to room temperature. The heat-treated laminate thus obtained was placed flat on a glass plate, and the maximum lift was measured as the amount of warpage. The insulation resistance, solder heat resistance and bending strength of each copper-clad laminate were measured according to JISC-64.
Performed according to No. 81. Table 2 shows the above measurement results.

As shown in Table 2, all the examples of the present invention were confirmed to have a smaller amount of warpage than Comparative Examples 1 and 2, and also exhibited performances with respect to insulation resistance, solder heat resistance and bending strength. It was confirmed that no decrease was observed.

[0026]

[Table 1]

[0027]

[Table 2]

[0028]

According to the method for producing a copper-clad laminate according to the first aspect of the present invention, a core material is obtained by impregnating a glass nonwoven fabric with a resin varnish containing a radical polymerization type thermosetting resin and an inorganic filler. A glass cloth impregnated with a resin varnish containing a radical polymerization type thermosetting resin is laminated on both outer surfaces as a surface layer material, and a copper foil is laminated on at least one surface thereof, and then heat-cured to form an integrated body. With regard to the formed copper-clad laminate, warpage during processing can be reduced. If a copper-clad laminate with less warpage is used, troubles in the manufacturing process and the mounting process of the printed wiring board are reduced, so that the copper-clad laminate according to the production method of the present invention can be suitably used.

────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification symbol FI B32B 31/04 B32B 31/04 31/12 31/12 H05K 1/03 630 H05K 1/03 630F (56) References JP 4-272845 (JP, A) JP-A-5-57828 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B32B 1/00-35/00 H05K 1/03

Claims (1)

(57) [Claims] 1. A core material comprising a glass nonwoven fabric impregnated with a resin varnish containing a radical polymerization type thermosetting resin and an inorganic filler, and a resin varnish containing a radical polymerization type thermosetting resin on both outer surfaces of the core material. In a method for producing a copper-clad laminate, which is obtained by laminating a cloth impregnated product as a surface layer material, further laminating a copper foil on at least one surface thereof, and then heating and curing, a viscosity (η) of a resin varnish used for a core material is obtained. and _B), the manufacturing method of the copper-clad laminate, wherein the ratio of the viscosity of the resin varnish to be used for the surface layer material (eta _a) is η _B / η _a> 5.