Method of bonding flexible circuit to cicuitized substrate to provide electrical connection therebetween using different solders

A method of bonding first and second circuitized substrates to provide electrical interconnection therebetween, said method comprising:

• providing at least one conductive pad on a first substrate comprised of an organic dielectric material;
• providing a quantity of organic dewetting material of a predetermined configuration substantially adjacent said conductive pad;
• applying a quantity of solder paste holding a first melting point over said conductive paid and at least part of said organic dewetting material;
• providing a second substrate including a dielectric material having an aperture therein and at least one conductor located within and/or bridging said aperture, said second substrate being flexible in nature;
• securing a solder member having a second melting point greater than said first melting point to said conductor;
• stretching said second substrate across a frame and thereafter aligning said second substrate having said solder member secured to said conductor substantially parallel to said first substrate such that said solder member engages said solder paste;
• heating said first and second substrates to a temperature substantially equal to or above said first melting point but less than said second melting point sufficient to cause said solder paste to dewet from said organic dewetting material and form substantially about said solder member;
• and
• thereafter cooling said formed solder to form an electrical interconnection and bond between said first and second substrates.