US 5,489,750 A · Method of mounting an electronic part with bumps on a circuit board

Abstract

A method of mounting an electronic part with bumps on a circuit board is disclosed which enables bumps to be bonded to electrodes of the circuit board with certainty and which enables the judgement of the quality of bonding with precision. By making an area of the electrodes of the circuit board larger than those of the electrodes of the electronic part, the bumps heated and molten in the reflow soldering are spread over the electrodes of the circuit board to make its vertical cross-sectional configuration in a trapezoidal form. Therefore, the height dispersion of the bumps and the curvature of the circuit board are effectively absorbed whereby all the bumps can be bonded to the electrodes of the circuit board. Further, by measuring the planar area of the bumps, the judgement of the quality of bonding can be made with precision.

Claims14

Dependent claims

A method of mounting an electronic part with at least one bump on a circuit board, said method comprising:

providing the electronic part with at least one electrode having a first area;
providing the circuit board with at least one electrode having a second area larger than the first area and being formed of a single electrode lying along a single plane;
providing the at least one bump projectingly from the at least one electrode of the electronic part;
landing the at least one bump upon the at least one electrode of the circuit board;
effecting a reflow soldering to heat and melt the at least one bump, thereby bonding the at least one bump onto the at least one electrode of the circuit board;
and
spreading over the at least one bump heated and molten in the reflow soldering over the at least one electrode of said circuit board to produce a spread bump.

4 more elements

A method of mounting an electronic part with bumps on a circuit board, said method comprising:

providing the electronic part with electrodes, each having a first area;
providing the circuit board with electrodes, each having a second area larger than the first area;
providing the bumps projectingly from the electrodes of the electronic part;
landing the bumps upon the electrodes of the circuit board;
effecting a reflow soldering to heat and melt the bumps, thereby bonding the bumps onto the electrodes of the circuit board;
spreading over the bumps heated and molten in the reflow soldering over the electrodes of said circuit board to produce spread bumps;
using an X-ray to obtain a projected image of said bumps after said reflow soldering;
and
judging a state of joining of said bumps with the electrodes of said circuit board from said projected image.

6 more elements

Dependencies are inferred from the claim text.

Method of mounting an electronic part with bumps on a circuit board

Life of this patent

Method of mounting an electronic part with bumps on a circuit board

Life of this patent

Abstract

Claims14