Integrated electronic device having flip-chip connection with circuit board and fabrication method thereof

A method for fabricating an integrated electronic device having an electric connection between a first electrode of a first substrate and a second electrode of a second substrate comprising the steps of:

• forming a first bump made of a first metal component on the first electrode, a surface of the first electrode having repellency against melt of the first metal component;
• forming a second bump made of a second metal component on the second electrode, the second bump being opposite to the first bump in a position, a surface of the second electrode having an adhesive tendency to melt of the second metal component, and the second metal component having a melting temperature lower than a melting temperature of the first metal component;
• and
• forming a connection part between the first bump and the second bump by melting the second bump at a temperature lower than the melting temperature of the first metal component and then solidifying the second bump so as to make the electric connection between the first electrode and the second electrode.

A method for fabricating an integrated electronic device having an electric connection between a first electrode of a first substrate and a second electrode of a second substrate comprising the steps of:

• forming a first metal layer on a surface of a first electrode on a first substrate, the first metal layer capable of composing an eutectic alloy with gallium (Ga);
• forming a bump of Ga-rosin mixture on the first metal layer selectively;
• and
• forming the electric connection between the first electrode and the second electrode by heating the bump of Ga-rosin mixture maintaining the bump of the Ga-rosin mixture in contact with the second electrode to react gallium in the Ga-rosin mixture with the first metal layer into the alloy capable to adhere to the first and second electrodes.