Lead-free solder paste
AssigneeSenju Metal Industry Co., Ltd.
InventorsRikiya Katoh, Osamu Munekata, Yoshitaka Toyoda
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Abstract
A lead-free solder paste suitable for soldering chip parts includes a powder of a twin-peak Sn-based solder alloy containing 0.2-1.0 mass % of Ag and a flux. The solder alloy has a first peak of heat absorption in a differential scanning calorimeter curve at the start of melting and a second peak when the major portion of the alloy subsequently melts.
Claims24
A soldering method comprising performing reflow soldering of leadless chip components on a printed circuit board using a lead-free solder paste which comprises a lead-free solder alloy powder mixed with a flux, the solder alloy powder having a twin-peak alloy composition including 0.2-1.0 mass % of Ag and at least 90 mass % of Sn and having a first peak of heat absorption in a differential scanning calorimeter curve at the start of melting of the solder alloy and a second peak when the major portion of the solder alloy subsequently melts.
A soldering method comprising soldering of chip components to a substrate using a lead-free solder paste which comprises a lead-free Sn-based solder alloy powder mixed with a flux, the solder alloy powder having a twin-peak alloy composition including 0.2-1.0 mass % of Ag and having a first peak of heat absorption in a differential scanning calorimeter curve at the start of melting of the solder alloy and a second peak when the major portion of the solder alloy subsequently melts.
Dependencies are inferred from the claim text.