Flux resin composition, electronic component, method for manufacturing the electronic component, mounting structure, and method for manufacturing the mounting structure

A flux resin composition containing:

• 60% by weight to 80% by weight of an epoxy resin;
• 0.01% by weight to 2% by weight of an imidazole compound;
• 1% by weight to 5% by weight of a thixo agent;
• 4% by weight to 20% by weight of an activator;
• and
• 7% by weight to 30% by weight of a phenolic compound,
• the epoxy resin containing at least one resin selected from the group consisting of naphthalene type epoxy resins, biphenyl aralkyl type epoxy resins, trisphenol methane type epoxy resins, biphenyl type epoxy resins, and dicyclopentadiene type epoxy resins, content of the at least one resin falling within a range from 15% by weight to 40% by weight with respect to a total weight of the flux resin composition,
• the phenolic compound being liquid and containing a phenol novolac;
• wherein a coverage rate of the flux composition being at least 10% when tested according to the follow test procedure:
• a bump with a diameter of 300 μm formed on a substrate having n Ni—Pd—Au pad with @ of 300 μm and 0.5 mmP, and a reflow process carried out according to the reflow profile of FIG. 1, wherein the dashed curve indicates the heating temperature, the solid curve indicates the viscosity of the flux resin composition (X), T3 (° C.) is a melting point of the bump, and T1 (C) and T2 (° C.) are particular temperatures that meet the relation:
• room temperature <T1<T2<T3;
• wherein coverage rate is equal to (HR/HB) × 100 (%), where HR is the height of a reinforcing portion and HB is the height of the bump.