公开(公告)号：US3827918A

公开(公告)日：1974-08-06

申请号：US25673572

申请日：1972-05-25

Applicant: IBM

Inventor： AMEEN T ,  MESLEY N

IPC: H01L21/60 ,  H05K3/34 ,  B44D1/18 ,  C23F7/26

CPC classification number: H01L24/81 ,  H01L2224/13111 ,  H01L2224/81801 ,  H01L2924/01013 ,  H01L2924/01019 ,  H01L2924/01024 ,  H01L2924/01029 ,  H01L2924/01033 ,  H01L2924/0105 ,  H01L2924/01082 ,  H01L2924/014 ,  H01L2924/14 ,  H05K3/3452 ,  H05K2201/0175 ,  Y10T428/12396 ,  H01L2924/00

Abstract: PRINTED CIRCUIT CONDUCTORS ARE SELECTIVELY COATED WITH A CHROMATE CONVERSION FILM TO CONFINE MOLTEN SOLDER TO SELECTED AREAS DURING REFLOW AND THEREBY PREVENT WICKING METHODS OF APPLICATION ALLOW IMMERSION COATING OF THE CHROMATE, EITHER WITH OR WITHOUT SOLIDIFIED, SOLDER PRESENT IN THE SELECTIVE AREAS. WITH SOLDER PRESENT, A PASSIVATION LAYER IS FORMED ON THE SOLDER TO PREVENT CHROMATING DEPOSITION, AND WITHOUT THE PRESENCE OF SOLDER A REMOVABLE PROTECTIVE RESIST IS APPLIED TO PREVENT CHROMATING ON THE SELECTED AREAS. THE CHROMATE CONVERSION COATING WITHSTANDS SUCCESSIVE FLUX APPLICATIONS AND REHATING FOR REPETITIVE ASSEMBLY AND DISASSEMBLY OF THE SOLDER JOINTS WITHOUT ALLOWING SOLDER RUNBACK.