Patent ID: 6077725
Filing Date: 2000-06-20
Classification: H01L,H05K

Abstract:
A method of assembling a multichip module having an array of high density contact pads on a silicon substrate and a matching array of contact pads on an integrated circuit chip, the method comprising the steps of:printing with automated surface mount equipment a solder paste selectively onto the contact pads of the substrate to form a solder paste pattern, the solder paste comprising a solder, a removing agent for metal oxides, a low temperature component that substantially evaporates below or at a reflow temperature but does not substantially evaporate at room temperature, a high temperature component that evaporates slowly at the reflow temperature, and a rheological modifier that allows said printing;positioning said integrated circuit chip with said automated surface mount equipment, in said positioning step, the contact pads on the integrated circuit chip being positioned in opposed alignment and in contact with the solder paste that forms the solder paste pattern; andheating with said surface mount equipment the solder paste at a reflow temperature to form solder joints between the contact pads on the substrate and the contact pads on the integrated circuit chip.