PURPOSE: To effectively protect a copper circuit even if it is heated plural times and to prevent deterioration of solderability, a decrease thereof after soldering by sequentially forming a palladium-plated film and a gold-plated film on a copper metal to be mounted with a component by soldering.
CONSTITUTION: A palladium-plated film is formed on a copper metal of a printed circuit board having a conductor circuit of the copper metal and a solder resist pattern formed thereon by using electroless palladium plating solution, and then a gold-plated film is formed on the palladium-plated film by using electroless plating solution. The thus obtained printed circuit board has a very small decrease in solderability through thermal hysteresis and excellent uniformity in thickness of the protective film, thereby providing excellent mounting stability of a surface mounting component. Further, a solder bridge does not occur.
UCHIDA MAMORU
OKADA TAKASHI
UCHIDA HIROKO
NAWAFUNE HIDEMI
MIZUMOTO SHOZO
| JPS63224290A | 1988-09-19 | |||
| JPH01117390A | 1989-05-10 | |||
| JPS59175755A | 1984-10-04 | |||
| JPH03237735A | 1991-10-23 | |||
| JPH0484449A | 1992-03-17 | |||
| JPS5233071A | 1977-03-12 | |||
| JPS58194392A | 1983-11-12 | |||
| JPH02265294A | 1990-10-30 | |||
| JPH01253990A | 1989-10-11 | |||
| JPH03240293A | 1991-10-25 | |||
| JPH02262395A | 1990-10-25 | |||
| JPH01257394A | 1989-10-13 |
Next Patent: METHOD FOR GOLD-PLATING BOARD ON WHICH ELECTRONIC COMPONENTS ARE MOUNTED