Paste composition and semiconductor device

A paste composition comprising:

• silver particles (A);
• a thermosetting resin (B);
• a curing agent (C);
• and
• a solvent (D),
• wherein a shrinkage rate after curing of the paste composition is 15% or less,
• wherein the silver particles (A) comprise silver particles (A1) and/or silver particles (A2),
• wherein the silver particles (A1) are secondary aggregate particles that have an average particle diameter from 0.5 μm to 2.0 μm and that are aggregates of particles including primary particles having an average particle diameter from 10 nm to 100 nm,
• wherein the silver particles (A1) are hollow particles comprising an outer shell formed by particles including aggregated primary particles and a void present inside the outer shell
• wherein the silver particles (A2) are secondary aggregate particles that have an average particle diameter of greater than 2.0 μm and 15.0 μm or less and that are aggregates of particles including primary particles having an average particle diameter of greater than 100 nm and 500 nm or less,
• wherein the silver particles (A1) have a porosity before sintering, as defined by Equation (1), from 20% to 50%, a porosity after sintering, as defined by Equation (1) and under sintering conditions including a nitrogen atmosphere, a sintering temperature from 175 to 225° C., and a sintering time from 1 to 3 hours, from 30% to 60%, and a rate of change in outer shell thickness due to sintering, as defined by Equation (2), from 15% to 50%:
• Porosity (%)=Total cross-sectional area of pore portions/Total cross-sectional area×100 (1)
• where the total cross-sectional area of pore portions is a sum of cross-sectional areas (μm2) of pore portions included in all silver particles in a visual field when cross sections of silver particles (A1) cut by an ion milling device are observed with a field emission scanning electron microscope (FE-SEM), and the total cross-sectional area is the sum of cross-sectional areas (μm2) of all silver particles in the visual field,
• Rate of change in outer shell thickness due to sintering (%)=(TA−TB)/TA×100 (2) where TA is the outer shell thickness (μm) before sintering and TB is the outer shell thickness (μm) after sintering under the sintering conditions.