Patent ID: 7167375

Claim:
A populated printed wiring board comprising: a printed wiring board comprising: a major surface; a plurality of copper pads on the major surface; a plurality of components including: one or more components selected from the group consisting of microchips and discrete components; and one or more components selected from the group consisting of electrical connectors and shields; and a plurality of solder joints between said plurality of copper pads, and said plurality of components, said plurality of solder joints comprising a lead-free solder, wherein said plurality of solder joints are formed by coating said copper pads with an organic solderability preservative, depositing a solder paste that includes said lead-free solder over said organic solderability preservative placing contact areas of the plurality of components in contact with said solder paste and heating said printed wiring board in an air atmosphere; wherein: said solder paste has a thickness T when applied to said copper pads; a minimum inter-pad spacing of said pads is S; and a ratio of the solder paste thickness to the minimum inter-pad spacing T/S is at least 0.5; wherein said plurality of components are all surface mounted onto said printed wiring board.