×

Method and apparatus for assembling multichip modules

  • US 5,564,617 A
  • Filed: 06/07/1995
  • Issued: 10/15/1996
  • Est. Priority Date: 09/03/1992
  • Status: Expired due to Term
First Claim
Patent Images

1. An apparatus for assembling a multichip module having an array of high density contact pads on a substrate and a matching array of contact pads on an unpackaged device, the apparatus comprising:

  • a solder paste, and wherein said solder paste includesa) a solder,b) a removing agent for metal oxides,c) a low temperature component that substantially evaporates below or at said reflow temperature but does not substantially evaporate at room temperature,d) a high temperature component that evaporates slowly at the reflow temperature,e) a rheological modifier that allows said printing, andf) a flux mixture consisting of diphenic acid, propyl-4-hydroxy benzoate, ethyl cellulose, castor oil, rosin gum and poly-propylene glycol;

    means for printing the solder paste selectively onto the contact pads of the substrate for forming a solder paste pattern;

    means for positioning in opposed alignment and in contact the contact pads on the device and the solder paste that forms the pattern; and

    means for heating the solder paste at a reflow temperature for forming solder joints between the contact pads on the substrate and the contact pads on the device.

View all claims
  • 7 Assignments
Timeline View
Assignment View
    ×
    ×