Adhesive compsn. which can be cured by UV light - used to fix components to hybrid substrates before solder reflow process and can be exposed by radiation through substrate

摘要

Using a substrate of alumina or Al-nitride with a thickness of not more than 1.5 mm, pref less than 1.1 mm, best less than 0.7 mm, active and passive components are glued using a UV cured adhesive. The feature is that the adhesive is applied to the substrate, the components are placed and the adhesive is then cured by irradiation through the substrate. The UV-radiation pref has an energy density of at least 50 mW/cm2, esp at least 100 mW/cm2. The adhesive used is pref a cationic and/or radical cured resin, pref including a cationic cured epoxy resin and/or a radial cured acrylate type resin. The adhesive pref also contains a heat conductive filler and/or a thixotropic agent. Also added may be additives to improve the wetting and/or the adhesion. USE/ADVANTAGE - The resin can be cured after placement of the components in a way which does not expose the components to harmful influences. The adhesion obtd secures the components before reflow soldering, ensuring improved process yield by the elimination of tombstoning and redn of solder-bridging. It also gives a reduced sensitivity to handling. The resin is used in the mfr of hybrid circuits made in thin or thick film processes.