1 Reverse Breakdown Voltage Studies Use Minglee’s leakage current as a function of reverse bias voltage measurements to look for evidence of ESD at array level. Post-hoc analysis of arrays with dead TX and reverse leakage data available gives no hints. Statistical analysis of full data set from Minglee –excludes files with strange leakage behaviour, one or more channels with leakage current> 1 nA for V<10V). –This leakage is not an artefact of the test system but is not correlated with ESD. –These devices were excluded from production to be safe.

2 Leakage vs Reverse Bias Voltage Define breakdown when leakage current > 1000 pA Determine bias voltage at which (a)>=1 channel in breakdown: V min (b)All 12 channels in breakdown: V max Plot Vmin and Difference  V= V max - V min

3 V min VV Tail on low side for V min, correlated with large  V, typically one channel with early breakdown. Tail on high side for  V All arrays with channels with  V>0.1 were excluded from production TXs

4 Taiwan QA Removed all TXs with strange data ie high leakage (>1 nA for low voltage). Removed all obvious suspicious TX with  V>= 0.1 V. Allowed through 5 intermediate cases with 0.06 <  V < 0.1 None of these 5 have died.

5 Profile plot of vs channel# For lowest voltage at which at least one channel in breakdown (I> 1000 pA). Why are edge channels worse (particularly channel 11) ? Not an artefact of test set-up Must be a handling issue or effect of wafer dicing.