Selective positioning of thermo curable materials using photolithography

Abstract

This dissertation studies about selective positioning of adhesive materials using photolithographic tech-nique. Polymeric materials have replaced conventional materials in packaging applications due to their light weight, simplicity of processing. Many kinds of polymeric adhesive materials are used in packaging process. Apply adhesive materials in selective area is useful for flip-chip packaging process. Adhesive bonding with flip- chip assembly provides thinner and lighter modules. For MEMS devices or CMOS image sensor (CIS) packag-ing, adhesive materials should be applied on selective areas. Among proposed processes for apply adhesive ma-terials in selective area, photolithographic technique is prospective process. Photolithographic technique is well-established. Wafer level photolithographic process is possible. In chapter 2, novel photopatternable and thermocurable non-conductive adhesives (PTNCAs) have been newly investigated in order to apply adhesive in selective region. For fast curing speed, epoxy-imidazole system was used. To minimize damage to epoxy functional group, non-chemically amplified system was introduced. Non-chemically amplified system does not require photoacid generator or post-exposure bake step. The prepared PTNCAs have three components, photoactive diazoketo groups, thermocurable epoxy groups, and aqueous base soluble carboxylic acid groups. DOBEMA(2-(2-diazo-3-oxo-butyryloxy)ethyl methacrylate) was used as methacrylate monomer containing diazoketo functional group. GMA(glycidyl methacrylate) was used as monomer containing thermocurable epoxy functional group. MAA(methacrylic acid) was used as aqueous base soluble carboxylic acid functional group. The PTNCAs were coated on wafers and patternwise exposed to deep ultraviolet irradiation. Exposed areas of PTNCA film were dissolved in an aqueous sodium carbonate solution and unexposed areas remained. As ratio of GMA increases, adhesion property is increased. But, patterning property is ...