A maskless flip-chip solder bumping technique

Conference · Tue Dec 31 23:00:00 EST 1991

OSTI ID:6896062

Chu, D; Shen, D S

Conventional flip-chip solder bumping, utilizing masks, evaporation, and plating equipment, is ideally suited for the mass production of components. Large batches of wafers can be deposited with multilayer solder at a single time. However, this process can be excessively costly, time consuming, and unnecessary for small, specialized applications. A process has been developed to solder bump individual pads, one at a time, without the need for expensive masks, evaporation chambers, or die layout information. This information, critical for solder bump placement, is typically not available to sources outside the design house. Using a standard ball wirebonder and specialized bonding wire, solder bumps can be formed on both Al and Au bond pads of integrated circuits (IC) using thermosonic bonding in a forming gas (Hydrogen-Argon) atmosphere. The bonding effectively wets the solder bump to the pad without the use of special intermetallic adhesion layers. This process can cut prototyping time and cost by eliminating the need for elaborate equipment and complex solder compositions without sacrificing electrical or thermal performance.

• Research Organization: Sandia National Labs., Albuquerque, NM (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6896062
• Report Number(s): SAND-92-2365C; CONF-9306104--4; ON: DE93009631
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101* -- Metals & Alloys-- Preparation & Fabrication
42 ENGINEERING
426000 -- Engineering-- Components
Electron Devices & Circuits-- (1990-)
ALLOYS
ALUMINIUM
BONDING
COST
DEPOSITION
ELECTRONIC CIRCUITS
ELEMENTS
FABRICATION
GOLD
INTEGRATED CIRCUITS
JOINING
LEAD ALLOYS
METALLURGICAL FLUX
METALS
MICROELECTRONIC CIRCUITS
SOLDERING
SUBSTRATES
TIN ALLOYS
TRANSITION ELEMENTS
WELDING