JPH07285195A - Production of metal foil clad laminated sheet - Google Patents

Abstract

PURPOSE:To obtain a metal foil clad laminated sheet reduced in warpage after heat treatment. CONSTITUTION:Epoxy resin glass fabric prepregs and resin sheets each having a thickness of 12mum composed of an epoxy resin produced using an extrusion molding machine are alternately superposed one upon another and copper foils are placed on both surfaces of the superposed one and the whole is molded under heating and pressure to obtain a copper clad laminated sheet with a thickness of 1.6mm. The resin sheets are preliminarily cured to a degree preventing the flow of the resin in the heating press molding process of the laminated sheet. The thickness sum total of the resin layer due to the resin sheets is set to 5-30% of the thickness of the laminated sheet.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は、印刷回路板用に適した
金属箔張り積層板の製造法に関するものである。FIELD OF THE INVENTION The present invention relates to a method for producing a metal foil-clad laminate suitable for printed circuit boards.

【０００２】[0002]

【従来の技術】近年、電子機器に用いられる印刷回路板
に部品を半田付けにより実装する工程は、生産効率の向
上に伴い特殊なものを除いてほぼ自動化されている。部
品実装形態もスルホール挿入方式から表面実装方式に変
わってきている。表面実装方式では、実装する部品にク
リーム半田を塗って印刷回路板の所定箇所に仮付けし、
リフロー炉で熱をかけることで半田を溶かして、部品を
印刷回路板に半田付けするようになっている。ところ
で、印刷回路板に使用する金属箔張り積層板は、その加
熱加圧成形中の樹脂の硬化収縮、プリプレグを挟む鏡面
板の影響等によって内部応力が残っている。そのため、
加熱加圧成形直後の製品では反りがないのに、印刷回路
の形成工程や上記の半田付け工程において積層板に熱が
かかると、積層板の隅や端に反りが発生する。印刷回路
形成工程で積層板が反ると、次の部品実装工程では反っ
た部分に部品が設計どおりに半田付けできなくなり、不
良品の発生につながる。また、半田付け時に反り始める
と、半田付け不良になる。これまでは、熱がかかったと
きの積層板の反りを小さくするために、ガラス転移温度
の高い樹脂を使用したり、積層板中の樹脂含有量を少な
くしたりしてきたが、積層板の加熱加圧成形時に硬化収
縮等が発生するかぎり、反りの抑制は不十分であった。2. Description of the Related Art In recent years, the process of mounting components on a printed circuit board used in electronic equipment by soldering has been almost automated, except for special ones, as production efficiency has improved. The component mounting mode has also changed from the through-hole insertion method to the surface mounting method. In the surface mounting method, solder paste is applied to the parts to be mounted and temporarily attached to a predetermined location on the printed circuit board.
Parts are soldered to a printed circuit board by melting the solder by applying heat in a reflow furnace. By the way, in the metal foil-clad laminate used for the printed circuit board, internal stress remains due to the curing shrinkage of the resin during the heating and pressurizing, the effect of the mirror surface plate sandwiching the prepreg, and the like. for that reason,
Although there is no warp in the product immediately after heat-press molding, when heat is applied to the laminate in the printed circuit forming step or the soldering step, the corners or edges of the laminate are warped. If the laminated plate warps in the printed circuit forming process, the component cannot be soldered to the warped portion as designed in the next component mounting process, resulting in defective products. In addition, if warping starts during soldering, soldering failure will occur. Until now, in order to reduce the warp of the laminate when heat is applied, we have used a resin with a high glass transition temperature or reduced the resin content in the laminate, but heating the laminate As far as curing shrinkage and the like occur during pressure molding, the suppression of warpage was insufficient.

【０００３】[0003]

【本発明が解決しょうとする課題】本発明が解決しよう
とする課題は、熱がかかったときの積層板の反りを小さ
くすることである。The problem to be solved by the present invention is to reduce the warpage of the laminate when heat is applied.

【０００４】[0004]

【課題を解決するための手段】上記の課題を達成するた
めに本発明に係る金属箔張り積層板の製造法は、シート
状基材に熱硬化性樹脂を含浸乾燥して得たプリプレグを
複数枚重ね、その表面に金属箔を載置して加熱加圧成形
する方法において、前記加熱加圧成形において流動しな
い程度に硬化させた熱硬化性樹脂シートをプリプレグ層
間に介在させて加熱加圧成形を行ない、前記熱硬化性樹
脂シートによる樹脂層の厚み合計を積層板厚さの５〜３
０％とすることを特徴とする。前記熱硬化性樹脂シート
は、さらに金属箔とプリプレグ間に介在させてもよい。In order to achieve the above object, a method for producing a metal foil-clad laminate according to the present invention comprises a plurality of prepregs obtained by impregnating and drying a sheet-like base material with a thermosetting resin. In a method of stacking sheets and placing a metal foil on the surface and performing heat-pressing, heat-pressing is performed by interposing a thermosetting resin sheet that is hardened so that it does not flow in the heat-pressing between the prepreg layers. And the total thickness of the resin layers formed by the thermosetting resin sheet is 5 to 3 of the laminated plate thickness.
It is characterized by being 0%. The thermosetting resin sheet may be interposed between the metal foil and the prepreg.

【０００５】[0005]

【作用】本発明に係る方法では、加熱加圧成形時の熱と
圧力では流動しない程度に硬化させた熱硬化性樹脂シー
トをプリプレグ層間に介在させて加熱加圧成形すること
により、実質的にその全面にわたって連続している樹脂
だけの層（シート状基材が含まれない層）が存在する積
層板を得られる。流動しない程度に硬化させた熱硬化性
樹脂シートを介在させることで、積層板の加熱加圧成形
に流動する樹脂の全体量が少なくなるので、成形した積
層板に残る内部応力は小さくなる。また、上記実質的に
その全面にわたって連続している樹脂だけの層は、シー
ト状基材が含まれないので低弾性であり、発生した応力
を緩和する作用をもっている。この樹脂だけの層の厚み
は、薄ければ応力を緩和する作用は小さくなるので反り
の抑制効果が不十分となる。逆に、樹脂だけの層の厚み
が厚すぎると、積層板自体の強度が小さくなってしまう
ので、印刷回路板に加工して部品を実装したときに部品
の重みで撓むことがある。熱硬化性樹脂シートにより形
成される樹脂だけの層の厚み合計は、積層板の板厚の５
〜３０％の範囲にすることが必要である。尚、樹脂含有
量が過剰のプリプレグを用いるか、プリプレグにさらに
樹脂液を塗布したプリプレグを用いて積層板を成形し、
樹脂だけの層をシート状基材層間に形成することが考え
られる。しかし、この方法では、樹脂だけの層の厚みを
一定にすることが難しく、当該層の厚みのばらつきによ
り積層板の板厚精度が悪くなる。また、積層板の加熱加
圧成形時に樹脂の流動が多いので、かえって反りが大き
くなってしまう。In the method according to the present invention, the thermosetting resin sheet cured to such an extent that it does not flow under the heat and pressure at the time of heat and pressure molding is interposed between the prepreg layers, and heat and pressure molding is substantially carried out. It is possible to obtain a laminated plate having a layer of only resin (a layer not containing a sheet-shaped substrate) which is continuous over the entire surface. By interposing the thermosetting resin sheet that is hardened so as not to flow, the total amount of the resin that flows in the heat and pressure molding of the laminated plate is reduced, so that the internal stress remaining in the molded laminated plate is reduced. Further, the resin-only layer which is substantially continuous over the entire surface has low elasticity because it does not include the sheet-shaped substrate, and has a function of relaxing the generated stress. If the thickness of this resin-only layer is small, the effect of relieving stress will be small, and the effect of suppressing warping will be insufficient. On the other hand, if the resin-only layer is too thick, the strength of the laminated plate itself will be reduced, and therefore when the printed circuit board is processed and the component is mounted, the component may be bent due to the weight of the component. The total thickness of the resin-only layer formed by the thermosetting resin sheet is 5 of the laminate thickness.
It is necessary to be in the range of -30%. In addition, using a prepreg having an excessive resin content, or using a prepreg obtained by further coating a resin liquid on the prepreg to form a laminate,
It is conceivable to form a layer of only resin between the sheet-shaped base layers. However, in this method, it is difficult to make the thickness of the layer made of resin constant, and the thickness accuracy of the laminated plate deteriorates due to the variation in the thickness of the layer. In addition, since the resin flows a lot during the heat and pressure molding of the laminated plate, the warpage becomes rather large.

【０００６】[0006]

【実施例】本発明に使用する熱硬化性樹脂は、ポリブタ
ジエン、エポキシ樹脂、フェノール樹脂、メラミン樹
脂、ジアリルフタレート樹脂、ケイ素樹脂など通常使用
されているもので、特に限定しない。また、積層板を難
燃化するために、ブロム化合物や三酸化アンチモン、五
酸化アンチモン、リン化合物、水酸化アルミニウム、水
酸化マグネシウムなどの難燃剤を配合してもよい。本発
明に使用するシート状基材は、紙、ガラス織布、ガラス
不織布といった電気絶縁用の積層板に通常使用されてい
るもので、特に限定しない。本発明に使用する金属箔
は、銅箔、ニッケル箔、アルミニウム箔などで、特に限
定しない。熱硬化性樹脂シートを構成する樹脂は、シー
ト状基材に含浸する樹脂と同じ樹脂を用いてもよいし、
違った樹脂を用いてもよい。同じ樹脂を用いると層間の
接着力は強くなる。熱硬化性樹脂シートには、粉末の充
填材が入っていてもかまわない。充填材を入れると樹脂
層の弾性率が大きくなるが、充填材が分散している分、
応力も分散できるためである。EXAMPLES The thermosetting resin used in the present invention is not particularly limited, and it is usually used such as polybutadiene, epoxy resin, phenol resin, melamine resin, diallyl phthalate resin and silicon resin. Further, in order to make the laminate flame-retardant, a flame retardant such as a bromine compound, antimony trioxide, antimony pentoxide, a phosphorus compound, aluminum hydroxide or magnesium hydroxide may be added. The sheet-shaped substrate used in the present invention is not particularly limited, since it is usually used for laminated sheets for electrical insulation such as paper, glass woven cloth and glass nonwoven cloth. The metal foil used in the present invention is a copper foil, a nickel foil, an aluminum foil or the like, and is not particularly limited. As the resin constituting the thermosetting resin sheet, the same resin as the resin with which the sheet-shaped base material is impregnated may be used,
Different resins may be used. When the same resin is used, the adhesive force between layers becomes strong. The thermosetting resin sheet may contain a powder filler. When the filler is added, the elastic modulus of the resin layer increases, but as the filler is dispersed,
This is because the stress can also be dispersed.

【０００７】（実施例１）エポキシ樹脂（油化シェル製
「Ｅｐ−１００１」，エポキシ当量５００）１００ｇ
に、ジシアンジアミド３ｇ、触媒として２−エチル４−
メチルイミダゾ−ル０．２ｇを配合し、ワニスを調製し
た。このワニスをガラス織布（単位重量１９０ｇ／
ｍ²）に含浸乾燥し、樹脂含有量が４０重量％のプリプ
レグを得た。また、押出し成形機を用いて、前記エポキ
シ樹脂からなる厚み１２μｍの樹脂シートを得た。この
樹脂シートは、積層板の加熱加圧成形工程で樹脂が流動
しない程度に硬化を進めてある。上記ガラス織布プリプ
レグ８枚と樹脂シート７枚を交互に重ね合わせ、両表面
に銅箔（厚さ１８μｍ）を載置して、温度１７０℃、圧
力４０Kg／cm²で６０分間加熱加圧成形して、板厚１．
６mmの銅張り積層板を得た（樹脂シートによる樹脂層の
厚み合計は積層板の５．３％）。Example 1 100 g of an epoxy resin ("Ep-1001" manufactured by Yuka Shell, epoxy equivalent 500)
To 3 g of dicyandiamide and 2-ethyl 4-catalyst
0.2 g of methyl imidazole was blended to prepare a varnish. This varnish was woven with glass (unit weight 190g /
m ² ) was impregnated and dried to obtain a prepreg having a resin content of 40% by weight. Further, a resin sheet having a thickness of 12 μm made of the epoxy resin was obtained by using an extrusion molding machine. This resin sheet is being cured to such an extent that the resin does not flow in the heat and pressure molding step for the laminated plate. 8 pieces of the above-mentioned glass woven prepregs and 7 sheets of resin sheets are alternately laminated, and a copper foil (thickness 18 μm) is placed on both surfaces, and heated and pressed at a temperature of 170 ° C. and a pressure of 40 kg / cm ² for 60 minutes. Then, the plate thickness 1.
A 6 mm copper-clad laminate was obtained (total thickness of resin layers formed by resin sheets is 5.3% of the laminate).

【０００８】（実施例２）実施例１のワニスをガラス織
布（単位重量１９５ｇ／ｍ²）に含浸乾燥し、樹脂含有
量が４０重量％のプリプレグを得た。また、押出し成形
機を用いて、実施例１と同様な厚み８０μｍの樹脂シー
トを得た。上記のガラス織布プリプレグ６枚と樹脂シー
ト５枚を交互に重ね合わせ、両表面に銅箔（厚さ１８μ
ｍ）を載置して、実施例１と同様に加熱加圧成形して板
厚１．６mmの銅張り積層板を得た（樹脂シートによる樹
脂層の厚み合計は積層板の２５％）。Example 2 A glass woven fabric (unit weight: 195 g / m ² ) was impregnated with the varnish of Example 1 and dried to obtain a prepreg having a resin content of 40% by weight. Further, a resin sheet having a thickness of 80 μm similar to that in Example 1 was obtained using an extrusion molding machine. 6 pieces of the above glass woven prepregs and 5 pieces of resin sheets were alternately laminated, and copper foil (thickness 18 μm was formed on both surfaces.
m) was placed and heat-pressed in the same manner as in Example 1 to obtain a copper-clad laminate having a plate thickness of 1.6 mm (total thickness of resin layers formed by resin sheets is 25% of the laminate).

【０００９】（実施例３）実施例１のワニスをガラス織
布（単位重量２０２ｇ／ｍ²）に含浸乾燥し、樹脂含有
量が４０重量％のプリプレグを得た。また、押出し成形
機を用いて、実施例１と同様な厚み１２０μｍの樹脂シ
ートを得た。上記のガラス織布プリプレグ５枚と樹脂シ
ート４枚を交互に重ね合わせ、両表面に銅箔（厚さ１８
μｍ）を載置して、実施例１と同様に加熱加圧成形して
板厚１．６mmの銅張り積層板を得た（樹脂シートによる
樹脂層の厚み合計は積層板の３０％）。Example 3 A glass woven fabric (unit weight: 202 g / m ² ) was impregnated with the varnish of Example 1 and dried to obtain a prepreg having a resin content of 40% by weight. Further, using an extrusion molding machine, a resin sheet having a thickness of 120 μm similar to that in Example 1 was obtained. Five pieces of the above-mentioned glass woven prepreg and four pieces of resin sheet were alternately laminated, and copper foil (thickness 18
μm) was placed thereon and subjected to heat and pressure molding in the same manner as in Example 1 to obtain a copper-clad laminate having a plate thickness of 1.6 mm (total thickness of resin layers formed by resin sheets is 30% of the laminate).

【００１０】（比較例１）実施例１のワニスをガラス織
布（単位重量１９２ｇ／ｍ²）に含浸乾燥し、樹脂含有
量が４０重量％のプリプレグを得た。Comparative Example 1 A glass woven fabric (unit weight: 192 g / m ² ) was impregnated with the varnish of Example 1 and dried to obtain a prepreg having a resin content of 40% by weight.

【００１１】また、押出し成形機を用いて、実施例１と
同様な厚み８μｍの樹脂シートを得た。上記のガラス織
布プリプレグ８枚と樹脂シート７枚を交互に重ね合わ
せ、両表面に銅箔（厚さ１８μｍ）を載置して、実施例
１と同様に加熱加圧成形して板厚１．６mmの銅張り積層
板を得た（樹脂シートによる樹脂層の厚み合計は積層板
の３．５％）。Using an extrusion molding machine, a resin sheet having a thickness of 8 μm similar to that in Example 1 was obtained. 8 pieces of the above-mentioned glass woven prepreg and 7 sheets of resin sheet were alternately laminated, copper foil (thickness 18 μm) was placed on both surfaces, and heat press molding was carried out in the same manner as in Example 1 to obtain a plate thickness 1 A copper-clad laminate having a thickness of 0.6 mm was obtained (the total thickness of the resin layers formed by the resin sheet is 3.5% of that of the laminate).

【００１２】（比較例２）実施例１のワニスをガラス織
布（単位重量１９６ｇ／ｍ²）に含浸乾燥し、樹脂含有
量が４０重量％のプリプレグを得た。また、押出し成形
機を用いて、実施例２と同様な厚み１４０μｍの樹脂シ
ートを得た。上記のガラス織布プリプレグ５枚と樹脂シ
ート４枚を交互に重ね合わせ、両表面に銅箔（厚さ１８
μｍ）を載置して、実施例１と同様に加熱加圧成形して
板厚１．６mmの銅張り積層板を得た（樹脂シートによる
樹脂層の厚み合計は積層板の３５％）。Comparative Example 2 The varnish of Example 1 was impregnated into a glass woven cloth (unit weight: 196 g / m ² ) and dried to obtain a prepreg having a resin content of 40% by weight. Further, a resin sheet having a thickness of 140 μm similar to that in Example 2 was obtained using an extrusion molding machine. Five pieces of the above-mentioned glass woven prepreg and four pieces of resin sheet were alternately laminated, and copper foil (thickness 18
μm) was placed and heat-pressed in the same manner as in Example 1 to obtain a copper-clad laminate having a plate thickness of 1.6 mm (total thickness of resin layers formed by resin sheets is 35% of the laminate).

【００１３】（従来例１）実施例１のプリプレグの片面
にさらに同じワニスを塗布して、厚さが１２μｍの樹脂
層を形成した。このプリプレグを８枚重ね合わせ、両表
面に銅箔（厚さ１８μｍ）を載置して、実施例１と同様
に加熱加圧成形して板厚１．６mmの銅張り積層板を得た
（ガラス織布基材層間にできる樹脂層の厚み合計は積層
板の５．３％）。(Conventional Example 1) The same varnish was further applied to one surface of the prepreg of Example 1 to form a resin layer having a thickness of 12 μm. Eight of these prepregs were stacked, copper foil (thickness 18 μm) was placed on both surfaces, and heat and pressure molding was performed in the same manner as in Example 1 to obtain a copper-clad laminate having a plate thickness of 1.6 mm ( The total thickness of the resin layers formed between the glass woven fabric base layers is 5.3% of that of the laminated plate).

【００１４】（従来例２）実施例２のプリプレグを８枚
重ね合わせ、両表面に銅箔（厚さ１８μｍ）を載置し
て、実施例１と同様に加熱加圧成形して板厚１．６mmの
銅張り積層板を得た（ガラス織布基材層間にできる樹脂
層の厚み合計は０）。(Conventional Example 2) Eight prepregs of Example 2 were superposed, copper foils (thickness 18 μm) were placed on both surfaces, and heat and pressure molding was carried out in the same manner as in Example 1 to obtain a plate thickness 1 A copper-clad laminate having a thickness of 0.6 mm was obtained (total thickness of resin layers formed between glass woven fabric base layers is 0).

【００１５】上記の実施例、比較例、及び従来例で製造
した銅張り積層板の反り及び曲げ弾性率の測定結果を表
１に示す。反りの測定に用いた試料サイズは５００×５
００mmである。Table 1 shows the measurement results of the warpage and flexural modulus of the copper-clad laminates produced in the above Examples, Comparative Examples and Conventional Example. The sample size used to measure the warp is 500 x 5
It is 00 mm.

【００１６】[0016]

【表１】 [Table 1]

【００１７】上記の実施例は、金属箔とプリプレグ間に
樹脂シートを介在させて加熱加圧成形することを妨げる
ものではなく、樹脂シートによる樹脂層の厚み合計を積
層板厚さの５〜３０％とする限り、当初の課題を達成す
ることができる。The above embodiment does not prevent the heat and pressure molding by interposing the resin sheet between the metal foil and the prepreg, and the total thickness of the resin layers formed by the resin sheet is 5 to 30 of the laminated plate thickness. The initial task can be achieved as long as it is set to%.

【００１８】[0018]

【発明の効果】表１から明らかなように、本発明に係る
方法によれば、熱処理後の反りが小さい金属箔張り積層
板を製造することができる。この積層板は、印刷回路板
として使用したとき、印刷回路の形成工程や部品の半田
付け工程で反りが抑制されるので有用である。As is apparent from Table 1, according to the method of the present invention, a metal foil-clad laminate having a small warpage after heat treatment can be manufactured. When used as a printed circuit board, this laminated board is useful because warpage is suppressed in the printed circuit forming step and the component soldering step.

Claims (2)

【特許請求の範囲】[Claims] 【請求項１】シート状基材に熱硬化性樹脂を含浸乾燥し
て得たプリプレグを複数枚重ね、その表面に金属箔を載
置して加熱加圧成形する金属箔張り積層板の製造におい
て、 前記加熱加圧成形において流動しない程度に硬化させた
熱硬化性樹脂シートをプリプレグ層間に介在させて加熱
加圧成形を行ない、前記熱硬化性樹脂シートによる樹脂
層の厚み合計を積層板厚さの５〜３０％とすることを特
徴とする金属箔張り積層板の製造法。1. A method for producing a metal foil-clad laminate, comprising: stacking a plurality of prepregs obtained by impregnating and drying a sheet-shaped base material with a thermosetting resin, placing a metal foil on the surface of the prepreg, and heat-pressing. The thermosetting resin sheet cured so that it does not flow in the heat and pressure molding is interposed between the prepreg layers to perform the heat and pressure molding, and the total thickness of the resin layers formed by the thermosetting resin sheet is the laminate thickness. Of 5 to 30% of the above. 【請求項２】加熱加圧成形において流動しない程度に硬
化させた熱硬化性樹脂シートを金属箔とプリプレグ間に
介在させる請求項１記載の金属箔張り積層板の製造法。2. The method for producing a metal foil-clad laminate according to claim 1, wherein a thermosetting resin sheet which is hardened so as not to flow in the heat and pressure molding is interposed between the metal foil and the prepreg.