Lead-free solder structure and method for high fatigue life

A method for forming an electronic structure, comprising the steps of:

• providing a first substrata and a second substrate;
• soldering a lead-free solder member to the first substrate without using a joining solder to effectuate the soldering, wherein the solder member consists essentially of a tin-antimony alloy, and wherein the tin-antimony alloy consists of about 3% to about 15% antimony by weight and a remainder consisting essentially of tin by weight;
• and
• soldering the solder member to the second substrate with a lead-free joiner solder.

An electronic structure, comprising:

• a first substrate;
• a second substrate;
• and
• a lead-free solder member soldered to the first substrate with no joining solder between the solder member and the first substrate, wherein the solder member is soldered to the second substrate with a load-free joiner solder, wherein the solder member consists essentially of a tin-antimony alloy, and wherein the tin-antimony alloy consists of about 3% to about 15% antimony by weight and a remainder consisting essentially of tin by weight.