JPS63254788A - Printed wiring board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a printed wiring board used in electronic equipment, and more particularly to a structure in which semiconductor chips are mounted.

2. Description of the Related Art Techniques such as film carrier and chip-on-board techniques already exist as methods for directly mounting semiconductor chips on printed wiring boards. The former method is not commonly used because of its complicated process and high cost. The flexibility of polyimide film, which is the base material, is not necessarily convenient for users, and its high cost also hinders its widespread use. Although the latter has been developed into common boards such as glass cloth epoxy boards and is replacing ceramic-based printed wiring boards, it is still difficult to test chip characteristics.
＜This has led to higher costs due to lower inspection yields for the number of semiconductor chips mounted.

Problem to be Solved by the Invention It is necessary to demonstrate the mounting of semiconductor chips on printed wiring boards at low cost and in a testable manner.

Means for Solving the Problems The present invention involves bonding a semiconductor chip onto a small piece of a child printed board using a die and wire, and then dripping epoxy resin and curing it to the C stain to form a protective coating resin. Mount the semiconductor chip with the mounting side facing the hole and cover the hole in the parent printed circuit board. The overall height of the semiconductor chip and its wire bonding portion is located within the depth of the hole in the parent printed circuit board.

According to the present invention, the surface wiring of a printed wiring board and the surface copper conductor of a sub-printed board on which a semiconductor chip is mounted are joined by solder in a surface-to-surface connection.

In other words, it is possible to perform reflow soldering using the solder paste printing method in the same way and simultaneously with the electrodes of other chip components. Furthermore, if a double-sided wiring chip carrier is used, chips can be mounted on both sides, and the space can be used for mounting wiring and other minute parts.

As illustrated in the embodiment, the semiconductor chip 4 is 1.2×1.6
mm, electrode connection terminal 14 for wire connection was used as child printed board 1, and 0.017 m thick copper foil 3 was adhered to 0.2 mm thick Aramide fiber impregnated with epoxy resin. Circular printed wiring board diameter 15I
IIl! Attach it to 1. It is of course possible to use solderable copper foil-resin paint or plated copper wiring. For the outer wire bond part, a part of the copper foil 3 is coated with gold and silver in advance.

Plating with nickel or the like to a thickness of 1 to 10 μm is performed. The arrangement pitch of the connection points of the bonding wires 5 is 0.2+a
It was set as m. Die bonding is done with solvent-free silver paint 16
Curing was performed at 0°C for 30 minutes.

Then apply the epoxy resin paint dripping to a diameter of 9 mm.
wm to form the protective coating resin 9.

The maximum height of this hemisphere is approximately 1.5 mm.

The diameter of the opening 7 in the parent printed board 2 is approximately 10 mm.

Place the semiconductor chip face down. The counter electrode 3 prepared on the main printed board 2 is printed with solder paste (tin/lead 63/37) 6 like other chip components, and is heated at 215°C for 15 to 20 seconds. Solder joints connect together with electrodes 11 of chip components 10 such as other capacitor resistors. Depending on the board thickness, it is also possible to use a parent printed board 2 with an access hole, or to mount child printed boards with semiconductor chips mounted in the same holes on both sides of the parent printed board.

Effects of the invention The child printed board on which the semiconductor chip is placed is used separately from the parent printed board, and the plating for bonding, dripping and heat curing of the botting resin have already been done, so the parent print There is a cost advantage since no processing is required for the plate. Reflow soldering is performed on the underside of a semiconductor chip carrier face-to-face at the same time as other chip components. At this time, since the semiconductor mounting portion is inside the hole, it is not affected by overheating, contamination, etc. due to reflow solder, and reliability is improved. When a semiconductor chip is mounted on the bottom surface, the top surface can be used for other wiring and terminals, and floral soldering can be performed on wiring boards in different stages. Furthermore, if the slave board is a metal board, the metal plate can also be used as a heat sink.

[Brief explanation of drawings]

The drawings are cross-sectional views of embodiments of the present invention. 1... Child printed board, 2... Main printed board, 3... Copper conductor, 4... Semiconductor chip, 5... Bonding Wire, 6...
...Solder, 7...Hole in main printed board, 8...
. . . Copper foil of main printed board, 9 . . . Child printed board with semiconductor chip mounted, 10 . . . Chip components, 11 . . . Electrodes of chip components.

Claims (1)

[Claims] This is a mounting structure in which a child printed circuit board 1 is mounted with a semiconductor chip 4 mounted in a hole of a parent printed wiring board, and the thickness of the semiconductor chip mounted on the child printed wiring board and the portion occupied by bonding wires 5 to the semiconductor are A printed wiring board having a structure in which the total thickness of the printed wiring board 2 including the allowance does not exceed the thickness of the main printed board 2, the mounting part protrudes from the surface, and the electrode connection part is connected to the surface conductor of the main printed board. .