JP2004007008A - Insulating substrate with thin metal layer and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulating substrate having a thin metal layer, which allows production of a high-density wiring board, and to provide its manufacturing method. <P>SOLUTION: A thin metal layer is formed on a temporary substrate. The temporary substrate is placed on an insulating base material, which is made by impregnating a glass base material with a thermosetting resin, with the thin metal layer facing the insulating base material. Then the temporary substrate and insulating base material are bonded by thermo-compression bonding, and the temporary substrate is removed. In the above-mentioned production method, the quantity of the resin penetrating into the glass base material is increased so that the resin layer on the glass base material acts as an adhesive layer and that the thickness of the adhesive layer between the glass fabric of the insulating base material and thin metal layer becomes at least 5 μm after thermo-compression bonding. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to an insulating substrate with a thin metal layer used for manufacturing a high-density wiring board and a method for manufacturing the same.

The copper-clad laminate used in the manufacture of wiring boards is a laminate of copper foil electrolytically deposited on a stainless steel rotating drum and prepreg impregnated with thermosetting resin on a paper or glass base material There is. In this case, the thickness of the copper foil is as large as about 18 μm, 35 μm, and 50 μm. As a method of manufacturing a wiring board using a copper-clad laminate as described above, there are an etched foil method and a semi-additive method in which a circuit is processed by etching the copper-clad laminate. The etched foil method has a problem of side etching, and it is difficult to form a high-density wiring. The fineness and high density of wiring in the semi-additive method depend on the thickness of the underlying metal layer (copper foil). That is, the smaller the thickness of the underlying metal layer to be etched, the higher the etching accuracy.

Therefore, when forming a high-density wiring, a copper-clad laminate using a thin copper foil of 5 to 9 μm is used as a base, but an aluminum foil (about 50 μm in thickness) which is a carrier of the copper foil is physically or chemically formed. When the aluminum foil is mechanically removed, there is a problem that the aluminum foil is broken during the peeling due to lack of mechanical strength, and a large amount of hydrogen gas is generated when the aluminum foil is removed by etching with an etching solution. Other methods for forming a thin underlying metal layer include an electroless plating method, a vacuum evaporation method, and a sputtering method. The electroless plating method requires a step of treating the surface of the insulating substrate by a physical or chemical method to make the surface hydrophilic and rough, and also has low adhesion between the generated metal layer and the substrate.

For this reason, a method has been proposed in which the roughened surface of the copper-clad laminate obtained by etching the copper foil is subjected to electroless plating to improve the adhesive strength. Is irregularly reflected to expose a portion that should not be a resist pattern, so that a large amount of development residue remains. Vacuum film formation methods such as a vacuum deposition method and a sputtering method can stably form a metal layer of 1 μm or less on a smooth substrate, but the substrate may be, for example, a glass cloth-epoxy laminate or a glass cloth-polyimide laminate. In the case of using, due to the moisture adsorbed on the glass cloth and the solvent remaining in the resin layer, the water and the solvent are gasified under a high vacuum necessary for vapor deposition or sputtering, and the glass cloth to resin Peeling and voids occur at the interface.

For these reasons, there has been proposed a method of performing a vapor deposition or sputtering step in a separate step, forming a thin metal layer, and then laminating the thin metal layer with an organic substrate for a wiring board (JP-A-53-114074, JP-A-57-14074). -72851, JP-A-57-87359, JP-A-57-142355).
JP-A-53-114074 JP-A-57-72851 JP-A-57-87359 JP-A-57-142355

However, even in these methods, when the thickness of the thin metal layer becomes 3 μm or less, there is a problem that the thin metal layer corresponding to the intersection of the glass fibers constituting the glass cloth of the base material is damaged at the time of thermocompression bonding. is there. In this case, if the thickness of the thin metal layer is increased, damage to the thin metal layer is reduced. However, it is necessary to use a semi-additive method to stably form an ultra-high-density wiring having a wiring width of about 20 to 50 μm. It is essential that the base metal is thinner than 3 μm. The present invention provides an insulating substrate with a thin metal layer and a method for manufacturing the same, which enables the manufacture of a high-density wiring board.

The present invention is characterized by the following.
(1) A thin metal layer is formed on a temporary substrate, and the temporary substrate and an insulating substrate for a wiring board in which a glass base material is impregnated with a thermosetting resin. In the method of manufacturing an insulating substrate with a thin metal layer that removes the temporary substrate by laminating and integrating by heating and pressing, the amount of resin impregnated into the glass substrate is increased, and the resin layer on the surface of the glass substrate is A method for producing an insulating substrate with a thin metal layer, wherein the thickness of the adhesive layer between the glass cloth of the insulating base material and the thin metal layer is 5 μm or more after forming an adhesive layer and heating and pressing.
(2) The method for producing an insulating substrate with a thin metal layer according to (1), wherein the thickness of the thin metal layer is 5 μm or less.
(3) A thin metal sheet in which a thermosetting resin layer on the surface of a glass substrate of an insulating substrate in which a thermosetting resin is impregnated into a glass substrate serves as an adhesive layer, and a thin metal layer is provided outside the insulating substrate. An insulating substrate with a thin metal layer, wherein at least one surface of the insulating substrate with a thin metal layer has a thickness of an adhesive layer between the glass cloth of the insulating base material and the thin metal layer of 5 μm or more.
(4) The insulating substrate with a thin metal layer according to (3), wherein the thickness of the thin metal layer is 5 μm or less.
(5) A thin metal sheet in which a thermosetting resin layer on the surface of a glass substrate of an insulating substrate in which a glass substrate is impregnated with a thermosetting resin serves as an adhesive layer, and a thin metal layer is provided outside the insulating substrate. The thickness of the thin metal layer of the insulating substrate with a layer is 5 μm or less, and the thickness of the adhesive layer between the glass cloth of the insulating base material and the thin metal layer is at least 5 μm on at least one side of the insulating substrate with the thin metal layer. A wiring board manufactured by using the insulating substrate with a thin metal layer, wherein the metal thin layer is plated with copper and then subjected to circuit processing.

According to the present invention, damage to the thin metal layer during transfer of the thin metal layer, which has conventionally been a problem, can be drastically reduced, and the fine circuit pattern forming step can be stabilized.

As the temporary substrate, a film, a plate, or a roll of a polymer or metal is used. The metal thin layer is not limited to one formed on the entire surface of the temporary substrate, but may be one having a predetermined wiring pattern. The thickness is preferably 5 μm or less, more preferably 3 μm or less. The thinner the thickness, the more convenient it is to manufacture a high-density wiring board. The pressure for heating and compression between the temporary substrate and the insulating substrate for a wiring board is preferably 10 to 70 kgf / cm ² , and the temperature is preferably 100 to 200 ° C. The amount of resin impregnated in the glass substrate is increased so that the resin layer on the surface of the glass substrate becomes an adhesive layer as a result. The thickness of the adhesive layer needs to be 5 μm or more after thermocompression bonding. If it is less than 5 μm, damage to the thin metal layer cannot be prevented. The insulating substrate with a thin metal layer obtained according to the present invention is obtained by, for example, subjecting a copper foil to a surface treatment for forming a resist, forming a resist pattern → pattern plating → removing the resist pattern → circuit processing by quick etching to obtain a wiring board. To manufacture.

Claims (5)

A thin metal layer is formed on a temporary substrate, and the temporary substrate and an insulating substrate for a wiring board in which a glass substrate is impregnated with a thermosetting resin, such that the thin metal layer of the temporary substrate faces the insulating substrate. In the method of manufacturing an insulating substrate with a thin metal layer, which is integrated by laminating and heating and pressing to remove the temporary substrate, the amount of resin impregnated into the glass substrate is increased, and the resin layer on the surface of the glass substrate becomes an adhesive layer Wherein the thickness of the adhesive layer between the glass cloth of the insulating substrate and the thin metal layer is 5 μm or more after thermocompression bonding. (2) The method according to claim 1, wherein the thickness of the thin metal layer is 5 µm or less. A thermosetting resin layer on the surface of a glass substrate of an insulating substrate in which a thermosetting resin is impregnated into a glass substrate serves as an adhesive layer, and a thin metal layer provided with a thin metal layer outside the insulating substrate. An insulating substrate with a thin metal layer, wherein at least one side of the insulating substrate with a thin metal layer has a thickness of an adhesive layer between the glass cloth of the insulating base material and the thin metal layer of 5 μm or more. 絶 縁 The insulating substrate with a thin metal layer according to claim 3, wherein the thickness of the thin metal layer is 5 µm or less. A thermosetting resin layer on the surface of a glass substrate of an insulating substrate in which a thermosetting resin is impregnated into a glass substrate serves as an adhesive layer, and a thin metal layer provided with a thin metal layer outside the insulating substrate. A metal having a thickness of a metal thin layer of a substrate of 5 μm or less, and at least one surface of an insulating substrate with a metal thin layer having a thickness of an adhesive layer between a glass cloth of the insulating base material and the metal thin layer of 5 μm or more. A wiring board manufactured using an insulating substrate with a thin layer, wherein the metal thin layer is plated with copper and then subjected to circuit processing.