Thermosetting flux and solder paste
AssigneeKabushiki Kaisha Toshiba
InventorsKazutaka Matsumoto, Masahiro Tadauchi, Izuru Komatsu
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Abstract
The invention aims to provide a thermosetting flux suitable for solder bonding of a semiconductor element and an electronic part and making solder bonding with a high bonding strength and a high heat resistant strength at a high temperature possible and a paste containing the flux and a non-lead type solder paste and with respect to the thermosetting flux, an epoxy resin, a hardening agent, and at least one of rosin derivatives having functional groups reactive on the epoxy resin and selected from maleic acid-modified rosin, a fumaric acid-modified rosin, and acrylic acid-modified rosin are used. The flux can be used in form of a solder paste while being mixed and kneaded with the non-lead type solder alloy powder.
Claims9
A soldering method comprising:
- applying a solder paste comprising a thermosetting flux containing an epoxy resin, a hardening agent, a non-lead type solder alloy powder, and at least one rosin derivative having at least two carboxyl groups reactive on the epoxy resin and selected from a maleic acid-modified rosin, a fumaric acid-modified rosin, and an acrylic acid-modified rosin to an object part of a substrate having an electrode to be bonded,
- then mounting an object part to be bonded on the substrate;
- pre-heating the substrate and the mounted part at 150 to 180° C. for 0.1 to 10 minutes;
- and
- heating the resulting substrate and the mounted part at 200 to 300° C. for 0.1 to 30 minutes.
Dependencies are inferred from the claim text.