JP2003289181A - Method of manufacturing substrate for multilayered printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve accuracy in the interlayer thickness of a substrate for multilayered printed wiring board without producing any defective molded product. <P>SOLUTION: In a method of manufacturing a substrate for multilayered printed wiring board, a laminated board to the surface of which an uncured resin is adhered is used as an adhesive layer in a method of manufacturing multilayered printed wiring board by which a multilayered printed wiring board is manufactured, by forming a circuit on at least one copper-plated laminated board and superimposing, and integrating the laminated board upon and with the adhesive layer. <P>COPYRIGHT: (C)2004,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a laminated board used as a multilayer printed wiring board or the like. 2. Description of the Related Art A method for manufacturing a substrate for a multilayer printed wiring board includes a prepreg in which a base material such as glass cloth or aramid fiber cloth is impregnated with a synthetic resin such as an epoxy resin or a polyimide resin, and a metal foil-clad laminate. An inner circuit board having a circuit formed on the surface of the board is stacked, and these are stacked with a copper foil as necessary. In general, a plurality of the above-described components are prepared, and a large number of the above-mentioned components are alternately stacked on a metal plate called an intermediate plate or a mirror plate, and these are heated and pressed. [0003] Recently, there is a circuit board that requires impedance control.
The main factors that determine the impedance on a circuit board are:
The interlayer thickness, the circuit width, the dielectric constant, and the like are required to be small in order to operate the device as designed. Regarding the interlayer thickness, the required variation is ±
It is 10% or less, and even more severe ± 8% or less is required for applications equipped with rambus memory. [0004] However, in general, prepregs for multi-layer bonding, which are widely used, give top priority to the embedding property. In order to embed the steps in the inner layer circuit, the prepreg is made to have fluidity at the time of heating. Variations are very large. For example, in the case of a commonly used multi-layer adhesive prepreg, for example, a resin with a nominal thickness of 0.1 mm has a “resin flow” of 10% or more at 130 ° C to 150 ° C and a “melt flow” at 120 ° C to 140 ° C. Viscosity '' 25-60 Pas,
In many cases, the “curing time” at 160 ° C. to 180 ° C. is about 110 to 250 seconds. When this material is heated and pressed at 170 ° C. and 20 kg / cm ² , the in-plane end becomes thin due to the flow of the resin, and the interlayer thickness variation exceeds 13%. Not available. As a countermeasure, it is conceivable to use resin that has a low flow by changing the resin flow or melt viscosity.However, depending on the performance balance of the resin performance and the inner layer pattern shape, small voids (white holes) may be generated. Molding was poor. In view of the above problems, the inventor of the present invention has invented a method for improving the accuracy of the interlayer thickness without causing molding failure or the like. The contents will be described below. [0006] The present invention relates to the following. (1) At least one copper-clad laminate is formed as a circuit, and these are laminated with an adhesive layer and integrally molded to form a multilayer printed wiring board. A method for manufacturing a substrate for a multilayer printed wiring board, characterized by using an uncured resin adhered thereto. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In general, when manufacturing a multilayer printed wiring board, it is general that an inner circuit board and a prepreg are alternately overlapped and molded by heating and pressing.
In the present invention, a material obtained by attaching an uncured resin to the surface of a laminate is used instead of the prepreg. The prepreg refers to a state in which a fiber (cloth) made of glass, an organic substance, or the like is impregnated with a resin and semi-cured. The laminate is preferably of the same type as the internal circuit board. For example, when a glass epoxy copper clad laminate is used for the inner circuit board, it is preferable to use the same type of glass epoxy laminate for the laminate. As an example of a method of adhering the uncured resin to the laminate, an organic solvent is applied to the laminate so that the resin powder is easily adhered in advance, and then the resin powder is adhered by a method such as spraying or spraying. There is a method. Organic solvents include
A material which is easy to evaporate in the subsequent steps, that is, a material having a low boiling point and which does not remain in the laminated plate after heat molding is used. For example, methanol (boiling point 78.3 ° C.) or ethanol (boiling point 64.6 ° C.) is desirable. As another method, an electrostatic deposition method using static electricity or a transfer method using a roll or the like may be used. As the resin powder, an epoxy resin or a polyimide resin in a semi-cured state is used.
A type different from the resin of the prepreg to be adhered or a type different from the same type of resin may be used. After the powder is attached, if necessary, the powder may be dried or allowed to stand naturally before molding. There is also a method in which a liquid resin is applied, the thickness is made uniform by a spin coating method or the like, and then semi-cured by heating. The amount of adhesion is determined based on the volume required for embedding the inner layer circuit. Generally, the adhesion amount is increased by about 3% to 20% of the volume required for embedding. This is to ensure the flowability and the amount necessary for bonding other than embedding. In order to form a single piece by overlapping the above,
Heat and press. At this time, the uncured resin adhered to the laminate is used to fill the steps of the inner layer circuit, and the thickness between the layers is secured by the thickness of the laminate. By using a laminate instead of a prepreg, the thickness of the end portion is not reduced due to excessive flow of the resin. Examples and Comparative Examples First, as an inner circuit board, a glass epoxy double-sided copper-clad laminate MCL-E-67 (trade name of Hitachi Chemical Co., Ltd.) having a base material layer thickness of 0.1 mm and a double-sided copper foil of 35 μm was used. Was prepared, and a copper foil on both sides was formed into a circuit. The remaining copper foil area is about 70%
It is. As prepreg, for outside and inside, both are glass cloth nominal thickness 0.095mm, resin thickness 55% nominal thickness 0.12m
A multi-layer adhesive prepreg GEA-67N (trade name of Hitachi Chemical Co., Ltd.) was prepared. As a laminate, LE-E-67 having a base material layer thickness of 0.1 mm is used.
(Hitachi Kasei Kogyo Co., Ltd.) was prepared, and a resin powder was adhered to the surface. The amount of resin powder increased by 10% of the area required for embedding (27.0cm3 / 1000mm x 1000mm on one side)
And Using the above, a six-layer plate shown in Table 1 was prepared. As can be seen from Table 1, in Comparative Example 1, blurring (whitening due to insufficient resin) occurred at the end of the substrate of the middle prepreg, but in Example 1, such molding failure did not occur. . In addition, in the example, it can be seen that the variation between layers is small, and the thickness accuracy between layers is significantly improved as compared with the comparative example. [Table 1] According to the present invention, the present invention eliminates the thinning of the end portion due to the resin flow by using a material in which an uncured resin is adhered to the surface of a laminate instead of a prepreg. And the thickness accuracy can be improved. Also, by adjusting the resin content of the coated cloth when making the laminate itself, a laminate having high thickness accuracy is prepared, and this is used for the substrate for a multilayer printed wiring board of the present invention. Accuracy itself can be utilized.

Claims (1)

Claims: 1. A circuit is formed with at least one copper-clad laminate, and these are laminated with an adhesive layer and integrally molded.
What is claimed is: 1. A method for manufacturing a multilayer printed wiring board, comprising: using, as an adhesive layer, an uncured resin adhered to a surface of a laminated board.