DUAL-STAGE WAFER APPLIED UNDERFILLS

• Main Authors: CANELAS, DORIAN, A, GHOSH, KAYLAN, KYLES, AMANDA, W, COLE, EDWARD, E
• Format: Patent
• Language: English; French; German
• Published: 30.08.2006
• Subjects: ADHESIVES; BASIC ELECTRIC ELEMENTS; CHEMICAL PAINT OR INK REMOVERS; CHEMISTRY; COATING COMPOSITIONS, e.g. PAINTS, VARNISHES ORLACQUERS; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; CORRECTING FLUIDS; DYES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; FILLING PASTES; INKS; LAYERED PRODUCTS; LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT ORNON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM; MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVINGCARBON-TO-CARBON UNSATURATED BONDS; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; NATURAL RESINS; ORGANIC MACROMOLECULAR COMPOUNDS; PAINTS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; PERFORMING OPERATIONS; POLISHES; SEMICONDUCTOR DEVICES; THEIR PREPARATION OR CHEMICAL WORKING-UP; TRANSPORTING; USE OF MATERIALS THEREFOR; WOODSTAINS

A 100% non-volatile, one-part liquid underfill encapsulant is disclosed for application to the active side of a large wafer or integrated circuit chip. Upon coating, the encapsulant is converted to a liquefiable, tack-free solid by exposure to radiation, particularly in the UV, visible and infrared spectrum. The underfill-coated wafer exhibits outstanding shelf aging of months without advancement of cure. The large wafer can be singulated into smaller wafer sections and stored for months after which during solder reflow assembly, the wafer connects are fixed and the underfill liquefies, flows out to a fillet and transitions to a thermoset state on heat activated crosslinking.