There are three physical changes to the new generation of lead-free product. The first change is that there is a connection to the silicon substrate that has been brought to the surface. It is advised that the substrate be connected to source potential to get the maximum dynamic performance from the device. The second change is the width of the solder bars. The EPC2001, EPC2015, EPC2007, and EPC2014 all have 200μm wide solder bars compared with 250 μm in the prior generation. The EPC2010 and EPC2012 both have 250μm  wide solder bars compared with 300μm in the prior generation. The third change is that the height of the solder bars has been increased from 70μm +/-20 to 100 μm +/- 20 for all second generation parts. The added height allows for greater post-assembly clearance between the FET and the PCB. This clearance makes it easier to clean out foreign materials and avoids the harmful accumulation of particles.