Method of fabricating a BGA package having decreased adhesion
View Patent ↗Ball Grid Array packages having decreased adhesion of the BGA pad to the laminate surface and methods for producing same are provided.
1. A method of fabricating an electronic package having selectively controlled contact pad laminate surface adhesion comprising:
providing a dielectric substrate having a major surface;
providing a conductive foil wherein said foil has at least one side having a smooth portion thereof;
laminating said conductive foil to said major surface wherein said smooth portion contacts said major surface;
applying a negative acting resist to said conductive foil;
developing said resist forming openings;
etching exposed conductive foil, wherein said etching forms a connection pad,
wherein said smooth portion has a surface roughness less than about 1.0 micron and moves relative to the dielectric surface during thermal stress thereby reducing a tendency to fracture an electronic connection.
2. A method of fabricating an electronic package having selectively controlled contact pad-laminate surface adhesion, according to claim 1 , wherein said conductive foil comprises any conductive material selected from the group consisting of copper, aluminum, gold, silver, nickel, and chrome.
3. A method of fabricating an electronic package having selectively controlled contact pad-laminate surface adhesion, according to claim 1 , wherein said conductive foil comprises any material having high electrical conductivity.
4. A method of fabricating an electronic package having selectively controlled contact pad-laminate surface adhesion, according to claim 1 , wherein said smooth side has a surface roughness about 0.01 micron.