JPH0366195A - Copper clad board - Google Patents

Abstract

PURPOSE:To prevent virtually the generation of dimensional change induced by etching and its post heating by installing a resin layer which contains a specific amount of filler on an inner surface which faces a copper foil. CONSTITUTION:A copper foil 1 is laminated on both sides of a resin-impregnated base material which comprises cotton cloth impregnated with resin by way of a filler-impregnated resin layer 2. The cotton cloth 3 to be used comprises inorganic and organic fiber textile, such as glass fibers, polyamide fibers. Resin 4 is thermal plastic resin, such as epoxy resin and polyamide resin. A filler is an inorganic filler, such as aluminum hydroxide, silica powder, mica or inorganic fiber, such as glass fiber, potassium titanic acid fiber. The thickness of a filler-impregnated resin layer 2 is 10mum or more, preferably it is 30mum or more. The content of resin for the filler-impregnated resin layer is usually selected from the range between 20 to 80 weight percentage. However, selection of the range of resin content smaller than that of a laminated board comprising the cotton cloth 3 and the resin 4 is more preferable to inhibit dimensional change.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a copper-clad laminate for printed wiring, which undergoes almost no dimensional change due to etching or heating.

[Conventional technology]

Conventional copper-clad laminates for printed wiring are made by coating a sheet-like base material such as woven fabric or paper with a thermosetting resin such as epoxy resin, polyamide resin, or phenolic resin. It is manufactured by stacking multiple sheets, stacking copper foil on the outermost layer, sandwiching it between metal plates such as stainless steel, and inserting it between parallel hot plates and heating and pressurizing it. Copper-clad laminates manufactured in this way are subjected to etching and heating in the process of processing printed circuits and forming parts, but at this time, the stress remaining in the copper-clad laminates is released and the dimensions are improved. Changes and warpage occur, making it difficult to manufacture high-density multilayer wiring boards and automatically mount components.

Methods for reducing residual stress in the laminate and improving dimensional change characteristics include lowering the pressure during hot-pressing (Japanese Patent Publication No. 62-50305), and releasing pressure during hot-pressing to reduce residual stress. Stress is removed (Japanese Unexamined Patent Publication No. 59-85750), and residual stress is annealed by post-heating (Japanese Unexamined Patent Publication No. 60-85).
-127150) etc. have been proposed.

[Problem to be solved by the invention]

These methods have the problem that although the dimensional change characteristics upon heating are greatly improved, the dimensional changes occurring during etching are not improved at all.

The present invention provides a copper-clad laminate that undergoes almost no dimensional change during etching and subsequent heating.

[Means for Solving the Problem] According to the present invention, in a copper-clad laminate in which copper foil is laminated on both sides of a resin-impregnated base material made of a woven fabric impregnated with resin, at least the copper foil is in contact with the copper foil. 20-80% by weight on the inner surface
A distant relative is achieved by providing a resin layer containing a filler.

The present invention will be explained below with reference to drawings showing examples. Fig. 1 shows a resin-impregnated base material in which a woven fabric 3 is impregnated with resin, and copper V31 is laminated on both sides of the resin-impregnated base material through a filler-impregnated resin layer 2. Figure 2 shows the structure of a copper-clad laminate in which filler-containing resin layers 2 are provided on both sides of a plurality of resin-impregnated base materials and copper foil 1 is laminated. FIG.

The woven fabric used in the present invention may be a woven fabric made of inorganic or organic fibers such as glass fibers or boria fibers, or may be a woven fabric made by combining different types of fibers.

The resin may be a thermosetting resin such as an epoxy resin, a polyimide resin, or a bismaleimide resin, or a thermoplastic resin such as a fluororesin, and the resins used for the resin 4 and the filler-containing resin 2 may not be the same resin. It is preferable to use a resin having a high thermal engraving coefficient and a high glass transition temperature as the filler-containing resin. Fillers include aluminum hydroxide, silica powder,
These include inorganic fillers such as mica, talc, glass powder and glass peas, and inorganic fibers such as glass fiber and potassium titanate fiber, and these may be used alone or in combination of two or more.

The thickness of the filler-containing resin layer is 10 μm or more, preferably 30 μm or more. If the thickness is 10 μm or less, there is little effect in suppressing dimensional changes. The resin content of the filler-containing resin layer is selected in the range of 20 to 80% by weight, but the woven fabric 3
In order to suppress dimensional changes, it is preferable to select a resin content in a range smaller than the resin content of the laminate made of resin 4 and resin 4.

Next, to explain the method for manufacturing the copper-clad laminate according to the present invention, the method shown in FIG. It is manufactured by laminating the agent-containing resin and copper foil and then hot-pressing them.

The filler-containing resin layer 2 is usually used by coating it on the copper foil 1, but the filler-containing resin layer 2 may also be coated on a nonwoven fabric made of inorganic fibers.

Further, in the case shown in FIG. 2, it is usually constructed using a resin-impregnated base material in which a resin 4 is applied to the woven fabric 3 shown in FIG. 3, and filler-containing resin layers 2 are provided on both surfaces. The filler-containing resin layer is formed by a conventional method such as coating or dipping, but it is also possible to separately create a filler-containing resin layer by applying a filler-containing resin to a nonwoven fabric made of inorganic fibers. ,
It may be configured using a resin-impregnated base material or copper foil and may be hot-press molded.

[Effect]

Residual stress in copper-clad laminates is released during the etching and heating processes during circuit processing, causing dimensional changes, but residual stress in copper-clad laminates with conventional configurations maintains pressure during hot-press forming. It is thought that this occurs because curing shrinkage of the resin is restricted or plastic deformation occurs. This residual stress can be reduced by molding at low pressure, and can be removed by post-heating without applying pressure after hot-press molding, but it is not possible to reduce the dimensional change that occurs when etching HA f&. Can not. The dimensional change that occurs during etching of copper foil is due to thermal stress that occurs due to the difference in the amount of thermal shrinkage between the copper foil and the laminate during cooling from the heating temperature when hot-pressing the copper-clad laminate to room temperature. It is thought that residual stress occurs, and as the copper foil is etched, the force balance is disrupted and the laminate deforms, which manifests itself as a dimensional change. The in-plane thermal engraving characteristics of laminates are affected by the weave density and resin content of the woven fabric, but are generally different from the thermal expansion characteristics of copper foil, and although it is possible to match them, it will increase costs. .

The copper-clad laminate of the present invention has a filler-containing resin 2 whose thermal expansion properties are closer to those of the copper foil than the resin 4, and the in-plane rigidity of the laminate is also increased, thereby making it possible to etch the copper foil 1. It is thought that the dimensional change characteristics are improved because the deformation of the substrate due to the release of residual stress can be suppressed.

〔Example〕

Example 1 100 parts by weight of Araldite 8011 (brominated bisphenol A type epoxy resin, trade name manufactured by Ciba Geigy) as an epoxy resin, 4 parts by weight of dicyandiamide as a curing agent, and 0.0 parts by weight of benzyldimethylamine as a curing accelerator.
2 parts by weight was dissolved and applied to a glass cloth weighing 209 g/n (209 g/n), dried at 160"C for 4 minutes, and the resin content was 40% by weight.
A resin-impregnated base material was obtained. In addition, the same amount of glass powder (average fiber diameter 9 μm) as the epoxy resin was added to the above epoxy resin liquid.
, average fiber length 0.7 mm), and this was added to a thickness of 0°0.
It was coated on an 18 mm electrolytic copper foil and dried to obtain a copper foil with a filler-containing resin having a thickness of 50 μm.

8 sheets of the above resin-impregnated base material were stacked, and then the copper coated with the filler-impregnated resin was stacked and sandwiched between metal mold plates, and this was inserted between parallel hot plates and heated at 170'C for 60 minutes under pressure. 3
Hot pressure molded at 0 kg f/c+ft, thickness 1°6ff
A copper-clad laminate of II11 was obtained.

Example 2 100 parts by weight of Araldite 8011 (brominated bisphenol A type epoxy resin, trade name manufactured by Ciba Geigy) as an epoxy resin, 4 parts by weight of dicyandiamide as a curing agent, and 0.2 parts by weight of benzyldimethylamine as a curing accelerator.
Resin liquid A was prepared by dissolving part by weight in a solvent, and this was applied to a glass cloth with a tsubo of 209 g/rrf, and dried at 160°C for 2 minutes to form a resin-impregnated base material C with a resin content of 38% by weight. Obtained. In addition, for 100 parts by weight of Araldite 8011,
Dicyanthia 14 parts by weight, benzyldimethylamine 0
．． 3 parts by weight, the average fiber length is 9 μm, and the average fiber length is 0.
Dissolve 1000 parts by weight of 7mm glass powder in a solvent.
The mixed resin liquid B was applied to the resin-impregnated base material C, and 160
Dry for 2 minutes at °C until the thickness of the filled resin layer is 30 °C.
A resin-impregnated base material of μm was obtained. Layer 8 sheets of this, then layer copper foil with a thickness of 0.018 mm on both surfaces, sandwich it between metal plates for molds, insert it between parallel heating plates, and heat it to 170°C.
Heat and pressure molded for 60 minutes at a pressure of 30 kgf/cJ to a thickness of 1
．． Six copper-clad laminates were obtained.

Comparative Example 1 Resin liquid A used in the example was applied to a glass cloth with a basis weight of 209 g/rrf, and dried at 160°C for 4 minutes, resulting in a resin content of 4
A 2% by weight resin-impregnated base material was obtained. Eight sheets of this were stacked, and a copper foil having a thickness of 0.018 mm was superimposed on the outermost layer, which was then hot-press molded in the same manner as in the example to obtain a copper-clad laminate with a thickness of 1.6+++n.

Comparative Example 2 The laminate prepared in Comparative Example 1 was further kept under no pressure in a dryer at 170°C, heated for 60 minutes, and then allowed to cool to a thickness of 1.
A copper-clad laminate of No. 6a was obtained.

0.0. After drilling a hole of 9 m + n and measuring the distance between the holes with a projector, etching and heating at 170°C for 1 hour were performed, the distance between the holes was measured and the dimensional change rate with respect to the original dimensions was determined. Table 1 shows the results. Shown below.

Table 1 [Effects of the Invention] The copper-clad laminate for printed wiring according to the present invention has almost no dimensional change due to etching or heating, and the unevenness on the surface of the copper-clad laminate is reduced, so it has excellent printing characteristics.
It is also suitable as a steel-clad laminate for high-density printed wiring.

[Brief explanation of drawings]

1 and 2 are longitudinal cross-sectional views of a copper-clad laminate according to the present invention, and FIG. 3 is a longitudinal cross-sectional view of an example of a resin-impregnated base material used in the present invention. Explanation of symbols 1゜3゜ Copper foil woven fabric 2゜4゜ Filler-containing resin layer resin

Claims (1)

[Claims] 1. In a copper-clad laminate made by laminating copper foil on both sides of a resin-impregnated base material made of woven fabric impregnated with resin, a resin layer containing 20 to 80% by weight of a filler is provided at least on the inner surface in contact with the copper foil. A copper-clad laminate featuring: