Semiconductor Chip Attach Configuration Having Improved Thermal Characteristics

Abstract

An array of metal bodies are attached to a metal carrier by forming Metal bodies form metal inter-diffusions with carrier. The metal bodies are coined to form flattened body ends. A polymeric adhesive precursor is disposed onto the array and a semiconductor chip having a first surface including circuitry and an opposite second surface free of circuitry is attached to the adhesive precursor so that the second chip surface is in contact with the flattened ends of the arrayed metal bodies, which stop at the second surface.

1 - 26 . (canceled) 
     
     
         27 . A method for fabricating an apparatus comprising:
 attaching an array of metal bodies to a metal carrier by forming metal-to-metal interdiffusions between each body and the carrier;   coining the metal bodies to form flattened body ends;   disposing a polymeric adhesive precursor onto the array in a quantity to fill the space between the bodies; and   attaching a semiconductor chip having a first surface including circuitry and an opposite second surface free of circuitry to the adhesive precursor so that the second chip surface is in contact with the flattened ends of the arrayed metal bodies, which stop at the second surface.   
     
     
         28 . The method of  claim 27  wherein the step of attaching metal bodies includes the steps of:
 forming a spherical free air ball by melting the end portion of a metal wire protruding from the orifice of a capillary; 
 moving the capillary with the free air ball over a metal carrier; 
 pressing the free air ball onto the carrier and applying ultrasonic energy for attaching the ball to the carrier while concurrently forming metal interdiffusions between ball and carrier and squeezing the ball into the shape of a tapered body; 
 breaking off the wire from the tapered body; and 
 repeating the steps for forming an array of metal bodies attached to the metal carrier. 
 
     
     
         29 . The method of  claim 27  wherein the step of coining includes the steps of:
 placing a stiff board horizontally over the array of bodies; and 
 pressing the board onto the array of bodies to create a flat end for all bodies and to concurrently ensure uniform height for all bodies of the array. 
 
     
     
         30 . The method of  claim 27  further including the step of hardening the adhesive precursor by polymerization. 
     
     
         31 . The method of  claim 27  further including the step of using bonding wires to connect the circuitry on the first chip surface to electrical conductors.