JPH02113596A - Printed circuit board - Google Patents

Abstract

PURPOSE:To prevent a solder bridge or a short-circuit between leads from generating by a method wherein blocks for preventing the generation of the solder bridge or the short-circuit between leads are provided between pads. CONSTITUTION:Pads 2 for mounting a semiconductor integrated circuit are provided on a substrate 4, blocks 3 consisting of a solder resist are provided between the pads and lead parts 1 are respectively provided on the pads 2. The solder resist is normally used as a material, which covers conductor patterns on a printed circuit board to insulate them, and is widely used. Thereby, the generation of a solder bridge or a short-circuit between the leads can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to printed circuit boards, and more particularly to prevention of solder bridges between pads or short circuits between leads.

[Conventional technology]

Conventionally, even in surface-mounted printed circuit boards, the lead pitch of the semiconductor integrated circuits mounted thereon was relatively wide, so the pad spacing was sufficient, and problems such as solder bridges and shorts between leads were rare.

[Problem to be solved by the invention]

BACKGROUND ART In recent years, as semiconductor products have become more densely packed and smaller, semiconductor integrated circuits have become more densely packaged on printed circuit boards, and the semiconductor integrated circuits themselves have become smaller, leading to narrower lead pitches and bad pitches. For example, the lead pitch of vsop is 0.65 mm, and the lead pitch of VQF''P is as narrow as 0.5 mm.

For this reason, conventional printed circuit boards, which are simply provided with pads for mounting semiconductor integrated circuits on the above-mentioned substrate, have the disadvantage that solder bridges and inter-lead sheets are likely to occur during mounting.

[Means to solve the problem]

The printed circuit board of the present invention is characterized by having a solder bridge between pads and a block for preventing short circuit between leads.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, and is a longitudinal sectional view of a pad portion on which a semiconductor integrated circuit is mounted.

The configuration of FIG. 1 is as shown below.

Pads for mounting semiconductor integrated circuits on substrate: 4: 2
There is a solder resist block 3 between the pads. In FIG. 1, a lead portion 1 of the semiconductor integrated circuit is also schematically drawn on the pad.

Solder resist is a material that is commonly used to cover and insulate conductor patterns on printed circuit boards, and it has the advantage of being inexpensive and can be used as a solder resist block to prevent solder bridges.

A second embodiment of the invention is shown in FIG.

The configuration of the second embodiment is similar to that of the first embodiment described above, but in the second embodiment, the blocks are made of photoresist instead of solder resist.

Although solder resists are inexpensive, they have the disadvantage that they cannot be used in cases where extremely high precision is required. Since this second embodiment uses a photoresist using a mask, it has the advantage of high accuracy and the ability to provide blocks up to the very edge of the pad, or to accommodate even finer patterns.

〔Effect of the invention〕

In conventional printed circuit boards, when the spacing between pads becomes narrow, solder bridges or short circuits between leads tend to occur, but the present invention has the effect of preventing these problems.

[Brief explanation of drawings]

FIGS. 1 and 2 are longitudinal cross-sectional views of a pad portion on which a semiconductor integrated circuit is mounted, according to an embodiment of the present invention.

Claims (1)

[Claims] A printed circuit board having solder pads for surface mounting a semiconductor integrated circuit, characterized in that a solder bridge is provided between the solder pads or an insulating block is provided between the solder pads to prevent short circuit between the leads. substrate.