Semiconductor device with increased connection strength between solder balls and wiring layer

A semiconductor device comprising:

• (a) a semiconductor chip;
• (b) a wiring making electrical connection with said semiconductor chip, having first and second surfaces, and containing copper (Cu) therein;
• (c) a solder ball making contact with said wiring at said first surface and containing tin (Sn) therein;
• (d) a film substrate making contact with said wiring at said second surface, said film substrate being formed with a through-hole reaching said wiring;
• (e) an electrical conductor filling said through-hole therewith;
• (f) a first layer covering said electrical conductor therewith at the opposite side of said wiring, and made of gold;
• and
• (g) a second layer made of copper-tin alloy, sandwiched between said wiring and said solder ball, and having a thickness equal to or greater than about 1.87 micrometers,
• said solder ball, said film substrate, and said wiring being maintained at a temperature of at least a melting point of said solder ball, shear strength of the connection between said solder ball and said wiring being greater than shear strength of the connection between said solder ball and said wiring if said solder ball, said film substrate, and said wiring were maintained at a temperature less than said melting point of said solder ball.

A semiconductor device comprising:

• (a) a semiconductor chip;
• (b) a wiring making electrical connection with said semiconductor chip and containing copper (Cu) therein;
• (c) a solder ball making contact with said wiring and containing tin (Sn) therein;
• and
• (d) a layer made of copper-tin (Cu—Sn) alloy, sandwiched between said wiring and said solder ball, and having a thickness equal to or greater than about 1.87 micrometers,
• said semiconductor device resulting from the steps of:
• (a) forming said wiring on a substrate;
• (b) mounting said solder ball on said wiring;
• and
• (c) keeping a product resulting from said step (b), in inactive gas atmosphere or in reducing gas atmosphere at a temperature equal to or greater than a melting point of said solder ball,
• shear strength of the connection between said solder ball and said wiring being greater than shear strength of the connection between said solder ball and said wiring if said product resulting from step (b) were kept at a temperature lower than said melting point of said solder ball.

A semiconductor device comprising:

• (a) a semiconductor chip;
• (b) a wiring making electrical connection with said semiconductor chip and containing copper (Cu) therein;
• and
• (c) a solder ball making contact with said wiring and containing tin (Sn) therein, said solder ball containing lead (Pb) agglomerates scattering therein at a density of 20×104 mm−3 or greater,
• said semiconductor device resulting from the steps of;
• (a) forming said wiring on a substrate;
• (b) mounting said solder ball on said wiring;
• and
• (c) keeping a product resulting from said step (b), in inactive gas atmosphere or in reducing gas atmosphere at a temperature equal to or greater than a melting point of said solder ball,
• said density of said lead agglomerates scattering in said solder ball being greater than a density of said lead agglomerates in said solder ball if said product resulting from step (b) were kept at a temperature lower than said melting point of said solder ball.

A semiconductor device comprising:

• (a) a semiconductor chip;
• (b) a wiring making electrical connection with said semiconductor chip and containing copper (Cu) therein;
• and
• (c) a solder ball making contact with said wiring and containing tin (Sn) therein, said solder ball containing lead (Pb) agglomerates scattering therein, said lead agglomerates having a cross-sectional area of 10 square micrometers or smaller in average,
• said semiconductor device resulting from the steps of:
• (a) forming said wiring on a substrate;
• (b) mounting said solder ball on said wiring;
• and
• (c) keeping a product resulting from said step (b), in inactive gas atmosphere or in reducing gas atmosphere at a temperature equal to or greater than a melting point of said solder ball,
• said cross-sectional area of said lead agglomerates being smaller than a cross-sectional area of said lead agglomerates if said product resulting from step (b) were kept at a temperature lower than said melting point of said solder ball.