Applications of a laser-induced plasma pathway to testing of electronic modules (original) (raw)

2000, IEEE Design & Test of Computers

that utilizes a laser-induced plasma "switch" to provide the electrical pathway for AC and DC measurements of PWBs. We obtained DC resistance dis-Induced Plasma Pathway to crimination of less than 10 ohms and Our prior experiments did not exdistortion-free AC measurements of a plore the option of transfemng, or "in-2.5MHz oscillator signal with this jecting," a signal into the circuit, as technique. opposed to measuring or monitoring the Tesiing uf EIedronic Modules THE SMALLER FEATURES and multiple embedded signal layers of tc, day's printed wiring boards are making mechanical (pin contact) electrical test systems obsolete. The fragile interconnections on highly populated boards require the application of nondestructive, nonloading technologies to electrical testing. One such technology is laser-based noncontact testing (NCT), which accesses fine interconnection structures via plasma photoionization to complete the r e quired electrical signal pathways.' This method provides a nonloading, nondestructive electrical pathway, potentially enabling very high speed (greater than 1 GHz), dynamic electrical measurements. A laserbased NCT system is an excellent complement to the expensive test hardware (digital testers, oscilloscopes, computels) already on the manufacturing floor. Our previous article' explored the development of an NCT system