JPH02238697A - Manufacture of multi layered printed wiring board - Google Patents

Abstract

PURPOSE:To prevent circuit failure due to local damage at a stage for applying heat and pressure for forming one-piece lamination by machining the outside of a circuit pattern edge part of a bent part which is positioned at the corner part of an insulation supporting body previously. CONSTITUTION:Circuit patterns 1a and 1b which are positioned at corner part 2a of an insulation supporting body 2 constituting an inner-layer wiring layer of a multi-layer type printed-wiring substrate and at least whose corner side is formed in an arc are used. Thus, in a process for performing one-piece lamination by heating and applying pressure, force applied to the circuit pattern edge part 1a or the bent part 1b positioned at the corner part of the circuit pattern supporting body 2 is relaxed. Therefore, damage of a circuit pattern 1 in that part can be prevented, thus retaining a high reliability of inner-layer circuit pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an improvement in a method for manufacturing a multilayer printed wiring board.

(Prior Art) For the purpose of downsizing electronic devices, efforts are being made to downsize and improve the performance of electronic components. Printed wiring boards are no exception to this example; for example, multilayer wiring (circuit patterns) and higher density wiring are being promoted. Incidentally, the multilayer wiring, that is, the multilayer printed wiring board is generally manufactured in the following manner. For example, a rectangular insulating support (thin plate) with a predetermined circuit pattern 1 formed on its main surface, a part of which is shown in plan in FIG.
2 are laminated alternately with prepreg layers, and these are used as inner layers and integrated by pressure and heating to manufacture the required multilayer printed wiring board. The circuit pattern 1 disposed as the inner layer is usually formed by selectively etching the copper foil of a copper foil-clad thin plate, and the end portions 1a of the circuit pattern 1. Ia' and bent part 1b
．． Ib' etc. are formed at right angles.

(Problems to be Solved by the Invention) However, the multilayer printed wiring board manufactured as described above has the following problems. That is, when looking at manufactured multilayer printed wiring boards, defects are often found in the inner layer wiring, which impairs yield and reliability. As a result of studying this point, the present inventor confirmed that it is influenced by the shape of the inner layer circuit pattern 1, especially the shape of the circuit pattern near the corner portion 2a of the rectangular thin plate 2 supporting the circuit pattern 1. . In other words, if the end portion 1a of the circuit pattern 1 located near the corner portion 2a of the rectangular thin plate 2 or the curved portion 1b of the circuit pattern form a right angle or a straight line, a multilayer printed wiring board constructed by laminating and integrating Suppose that the damage (circuit failure) has occurred.

[Structure of the Invention] (Means for Solving the Problems) The present invention has been made in response to the above-mentioned circumstances, and is a multilayer structure in which a rectangular insulating support having a predetermined circuit pattern on its main surface is laminated and integrated as an inner layer. In the method for manufacturing a molded printed wiring board, at least a corner side of the circuit pattern located at a corner portion of the insulating support is formed into an arc shape.

(Function) In the above method for manufacturing a multilayer printed wiring board, at least the corner side of the circuit pattern located at the corner of the insulating support forming the inner layer is formed into an arc shape, so that heating and pressure can be avoided. In the step of laminating and integrating the circuit patterns, the force applied to the ends and curved portions of the circuit patterns located at the corners of the circuit pattern support is easily alleviated, and damage to the circuit patterns at those portions is effectively prevented. In this way, the inner layer circuit pattern can also maintain high reliability.

(Example) Examples of the present invention will be described below. First, the required pre-preg, for example, an epoxy resin-glass cloth pre-preg,
A rectangular insulating support having a predetermined circuit pattern on its main surface constituting an inner wiring layer (circuit pattern layer), for example, a rectangular epoxy resin/glass cloth thin plate having a predetermined circuit pattern on its main surface is prepared. FIG. 1 is a plan view showing an example of the structure of a rectangular insulating support 2 having a predetermined circuit pattern 1 forming an inner wiring layer adhered to its main surface. The circuit pattern La located at the corner portion 2a of the insulating support 2
．． Use Ib with at least the corner side formed in an arc shape.

Next, the prepreg and the predetermined circuit pattern 1 forming the inner wiring layer or the rectangular insulating support 2 formed on the main surface are alternately laminated, and then rectangular copper foil-covered epoxy resin-glass openings are formed on both sides. A desired multilayer printed wiring board can be manufactured by disposing thin metal plates, etc., and integrating them by heating and pressurizing them by conventional means.

In the above, an example is shown in which an epoxy resin/glass cloth system is used as the rectangular insulating support 2 having prepreg and a predetermined circuit pattern 1 adhered to the main surface. The material is not limited to this type, and may be, for example, a phenol resin-insulating paper system, or a prepreg or insulating support 2 using a polyimide resin as the resin. Furthermore, the insulating support 2
The circular arc shape formed at least on the corner side of the circuit pattern laib located at the corner portion 2a of is selected and set as appropriate depending on the width of the circuit pattern 1. For example, if the width of the circuit pattern 1 is approximately . 2-I.
Approximately 0 mm is sufficient.

[Effects of the Invention] In the method for manufacturing a multilayer printed wiring board as described above,
The outside of the circuit pattern end or curved portion located at the corner of the insulating support forming the inner layer circuit pattern is pre-processed, particularly into an arcuate shape.

Therefore, even at the stage of laminating the required prepreg layers and heating and pressurizing them to laminate them together, it is possible to prevent or reduce the possibility that the circuit pattern ends or bent portions located at the corners are subjected to local forces. , the damage in this part is significantly reduced.

Therefore, in the manufactured multilayer printed wiring board, the occurrence of defects in the inner layer circuit pattern is also suppressed, and a multilayer printed wiring board with high yield and high reliability can always be obtained. Moreover, the manufacturing method described above does not require particularly complicated operations, so it can be said that it brings many practical advantages.

[Brief explanation of drawings]

FIG. 1 is a plan view showing a part of an insulating support having an inner layer circuit pattern used in the method for manufacturing a multilayer printed wiring board according to the present invention, and FIG. 2 is a plan view showing a part of the insulating support body used in the conventional method for manufacturing a multilayer printed wiring board. FIG. 3 is a plan view showing a part of an insulating support having an inner layer circuit pattern. 1...Circuit pattern Ia...Corner part low path pattern end 1b.
...Circuit pattern bent part 2 at the corner part...
... Insulating support 2a ... Corner part (of the insulating support) Applicant
Toshiba Corporation

Claims (1)

[Claims] A method for manufacturing a multilayer printed wiring board in which a rectangular insulating support having a predetermined circuit pattern on its main surface is laminated and integrated as an inner layer, comprising: a circuit pattern located at a corner of the insulating support; A method for manufacturing a multilayer printed wiring board, characterized in that at least the corner side is formed in an arc shape.