Shown in FIG. 2A are three solder interfaces between the respective FETs 130, 140 and the clips 121, 122. There are solder bonded interfaces shown as 191, 192 and 193, with each solder bonded interface including disclosed protruding standoffs shown as 151 within solder interface 191, protruding standoffs 152 within solder interface 192, protruding standoff 161 within solder interface 193, and protruding standoffs 162 in solder interface 194. Disclosed standoffs 151, 152, 161, 162 on the FET die 130, 140 surface improves the BLT of the solder bonded interface which if uneven in thickness as described above is a potential reliability risk. Although not shown in FIG. 2A, the lateral extent of the solder interfaces 191, 192, 193 can be all within the boundaries of their protruding standoffs.

The protruding standoffs 151, 152, 161, 162 can have a protruding height of 10 to 30 μm, such as 15 μm to about 25 μm. The standoffs generally comprise a dielectric material, such as comprising solder mask, dry film, polyimide, silicon nitrite, or silicon oxide, or an epoxy that can be printed or can be dispensed. The protruding standoff(s) in one aspect is circular in shape and is 0.1 to 0.3 mm in center diameter, again being about 15 μm to 25 um in standoff height. The standoff height is generally at least equal to the thickness of the solder bonded interfaces so that the protruding standoffs extend from the vertical semiconductor die surface to physically contact their respective clip.