For example, for a 20 μm resistor, the channel should be long enough so that there is {HEAD ~ about 40 60 μm} between {TAIL ~ the resistors} 
For example , for a 20 μm resistor , the channel should be long enough so that there is { HEAD ~ about 40 60 μm } between { TAIL ~ the resistors }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL