Manufacture of a multi-layer interconnect structure

A process for extruding a pattern of paste onto a substrate, including the steps of:

• relatively positioning one side of a screening mask against a surface of the substrate;
• relatively positioning an elongate discharge end of a paste nozzle across a width of a second side of the screening mask which is opposite from the one side of the screening mask, with a clearance between the discharge end and the second side of the screening mask;
• injecting paste through the nozzle, out the discharge end and into the screening mask with sufficient pressure to completely fill an intricate pattern in the mask for extruding the pattern onto the substrate;
• traversing the discharge end of the paste nozzle across a length of the screening mask;
• maintaining said clearance between the nozzle discharge end and the second side of the screening mask approximately constant by load control means for maintaining an equilibrium between the a first force applied to the nozzle toward the mask by said load control means while traversing the screening mask and a force applied to said nozzle by said paste in a direction opposite to that of said first force, said clearance being sufficiently small to substantially contain the pressurized paste at the discharge end.

A process for manufacturing a multi-layer ceramic interconnect structure, comprising the steps of:

• perforating a greensheet with small through holes for producing conductive vias for electrical continuity between layers;
• positioning a first surface of a greensheet against a support surface;
• positioning a screening mask on a second surface of the greensheet on a side of the greensheet opposite from the support surface;
• positioning a discharge end of a paste nozzle proximate to a surface of the screening mask on a side of the screening mask opposite from the greensheet and with a small clearance between the discharge end and the surface of the screening mask by establishing approximate equilibrium between a first force applied to the nozzle toward the mask and a force applied to said nozzle by said paste in a direction opposite to that of said first force;
• injecting conductive paste through the nozzle, to the discharge end and into the mask with sufficient paste pressure to extrude a conductive pattern onto the greensheet and to fill the perforations in the greensheet with conductive paste to form the conductive vias;
• traversing the discharge end of the paste nozzle across the screening mask to extrude a conductive pattern across the surface of the greensheet and to fill the perforations to form the conductive vias for producing a patterned greensheet layer of the interconnect structure;
• stacking a multiple of said patterned greensheets to form a structure;
• sintering the structure under pressure and high temperature to produce the multi-layer ceramic interconnect structure.