公开(公告)号：GB2349014B

公开(公告)日：2003-10-22

申请号：GB0004103

申请日：2000-02-23

Applicant: IBM

Inventor： JOHNSON ERIC A ,  KRESGE JOHN S

IPC: H01L23/28 ,  H01L23/12 ,  H01L23/32 ,  H01L23/498 ,  H05K1/02 ,  H05K1/11 ,  H05K1/18 ,  H05K3/00 ,  H05K3/34 ,  H01L23/485

Abstract: A method and structure for reducing thermally induced strains on the solder joints that couple a ball grid array (BGA) module to a circuit card, so as to improve the fatigue life of the BGA module. The thermally induced strains arise from a mismatch in thermal expansion coefficient between the dielectric substrate of the BGA module and the dielectric board of the circuit card. The method generates void annular regions around portions of the BGA dielectric substrate to which the BGA solder balls are to be attached and/or around portions of the circuit card dielectric material to which the BGA module is to be attached. This results in the formation of dielectric islands or peninsulas that bound the solder balls of the BGA module after installation on the circuit card. The dielectric islands or peninsulas thus formed serve to increase the effective height over which the differential expansion is accommodated, thereby reducing the strains throughout the solder joints. Additionally, the void annular regions provide space for the deformation of the dielectric islands or peninsulas, thereby increasing their compliance and transferring strain from the solder joints to the dielectric islands or peninsulas.

公开(公告)号：SG92634A1

公开(公告)日：2002-11-19

申请号：SG1999001579

申请日：1999-03-31

Applicant: IBM

Inventor： JIMAREZ MIGUEL A ,  JOHNSON ERIC A ,  LI LI ,  OBRZUT JAN

IPC: H01L21/56 ,  H01L23/498 ,  H01L21/60

Abstract: Flip-chip electronic packages are provided with a compliant surface layer, normally positioned between an underfill layer and a substrate such as a chip carrier or a printed circuit board or card, which reduces stress and strain resulting from differences in coefficients of thermal expansion between the chip and substrate. The compliant layer, which should have a storage modulus of less than ½ the modulus of the substrate, preferably between about 50,000 psi and about 20,000 psi, may comprise rubbery materials such as silicone, virco-plastic polymers such as polytetrafluoroethylene or interpenetrating polymer networks (IPNs). Photosensitive IPNs used for solder marks are preferred.

公开(公告)号：MY138376A

公开(公告)日：2009-05-29

申请号：MYPI9901137

申请日：1999-03-25

Applicant: IBM

Inventor： JIMAREZ MIGUEL A ,  JOHNSON ERIC A ,  LI LI ,  OBRZUT JAN

IPC: H01L21/56 ,  H01L23/498

Abstract: FLIP-CHIP ELECTRONIC PACKAGES ARE PROVIDED WITH A COMPLIANT SURFACE LAYER, NORMALLY POSITIONED BETWEEN AN UNDERFILL LAYER AND A SUBSTRATE SUCH AS A CHIP CARRIER OR A PRINTED CIRCUIT BOARD OR CARD, WHICH REDUCES STRESS AND STRAIN RESULTING FROM DIFFERENCES IN COEFFICIENTS OF THERMAL EXPANSION BETWEEN THE CHIP AND SUBSTRATE. THE COMPLIANT LAYER, WHICH SHOULD HAVE STORAGE MODULUS OF LESS THAN ½ THE MODULUS OF THE SUBSTRATE, PREFERABLY BETWEEN ABOUT 50,000 PSI AND ABOUT 20,000 PSI, MAY COMPRISE RUBBERY MATERIALS SUCH AS SILICONE, VIRCO-PLASTIC POLYMERS SUCH AS POLYTETRAFLUOROETHYLENE OR INTERPENETRATING POLYMER NETWORKS (IPNS). PHOTOSENSITIVE IPNS USED FOR SOLDER MARKS ARE PREFERRED.

公开(公告)号：MY127450A

公开(公告)日：2006-12-29

申请号：MYPI20004784

申请日：2000-10-12

Applicant: IBM

Inventor： CALETKA DAVID V ,  JOHNSON ERIC A

IPC: H01L21/44 ,  H01L21/60 ,  H01L23/48 ,  H01L23/498 ,  H05K1/11 ,  H05K3/34

Abstract: A METHOD OF FORMING BGA INTERCONNECTIONS HAVING IMPROVED FATIGUE LIFE IS DISCLOSED.IN PARTICULAR,A COMBINATION OF MASK-DEFINED AND PAD-DEFINED SOLDER JOINTS (40,42) ARE SELECTIVELY POSITIONED WITHIN THE BGA PACKAGE (36).THE MASK-DEFINED SOLDER JOINTS POSSESS A HIGH EQUILIBRIUM HEIGHT,WHICH FORCES THE PAD-DEFINED SOLDER JOINTTS TO ELONGATE, THEREBY MAKING THE PAD-DEFINED SOLDER JOINTS MORE COMPLIANT. FURTHER, THE PAD-DEFINED SOLDER JOINTS POSSES A SLIGHTLY LONGER FATIGUE LIFE BECAUSE THE STRESS CONCENTRATIONS FOUND IN THE MASK-DEFINED SOLDER JOINTS ARE NOT PRESENT IN THE PAD-DEFINED SOLDER JOINTS.THEREFORE , THE FATIGUE LIFE OF BGA PACKAGES IS INCREASED BY IMPLEMENTING A MAJORITY OF MASK - DEFINED SOLDER JOINTS TO MAINTAIN A HIGH EQUILIBRIUM HEIGHT,AND SELECTIVELY PLACING PAD-DEFINED SOLDER JOINTS IN HIGH STRESS AREAS OF THE BGA PACKAGE.(FIG. 1)