Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Making electrical device
Patent
1993-12-21
1995-12-26
Owens, Terry J.
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Making electrical device
427 96, 427259, 427282, 427294, 29852, 22818022, 118406, G03F 716, B05D 512, B23K 3102
Patent
active
054787009
ABSTRACT:
A method of applying bonding agents, such as solder pastes and conductive adhesives, to pad sites in the manufacture of electronic circuits uses a bonding agent injection head which includes a wiping guide, a blade which cooperates with the wiping guide to form an elongate nozzle slit, and an evacuation path ahead of the nozzle slit in a direction of movement of the injection head. A permanent mask with cavity openings is applied around conductive pads on a carrier. The conductive pads correspond to chip attachment sites. The injection head is brought into contact with a surface of the mask, and pressure is applied to a bonding agent in the injection head. The injection head is then moved over the surface of the mask, filling cavity openings with the bonding agent. The evacuation path ahead of the nozzle slit lets air out of the cavity openings as the cavity openings are filled with bonding agent. The injection head is then removed from the surface of the mask. If a solder paste is used, infrared radiation is applied to filled cavity openings to evaporate a paste flux and reflow solder to form solder balls within the cavity openings projecting above the mask. If a conductive adhesive is used, a stencil is applied to the surface of the mask prior to contacting the mask with said injection head. When the cavity openings are filled, the stencil is removed from the mask and the conductive adhesive filling the cavity openings is dried.
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Gaynes Michael A.
Oxx George D.
Pierson Mark V.
Zalesinski Jerzy
Belk Michael
International Business Machines - Corporation
Owens Terry J.
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