Integrating pulsed laser for a galvo mirror based SEE scanning microscope with optical failure analysis capabilities

Abstract

This paper presents the characterization, stability and potential pitfalls to setting up of an alternate pulsed laser Single Event Effect (SEE) system. This system involves the integration of a pulsed laser to an existing commercial optical failure analysis tool based on the galvo mirror scanning microscope scheme. This newly proposed system aims to provide a stable and precise solution to conduct pulsed laser SEE tests on advanced microelectronic devices with small feature sizes. The use of galvo mirrors demonstrated the potential of fine pitch targeting of the laser spot in the x-y axis domain. Laser energy stability was quantified via measurements conducted over a period of 8 months and characterization of laser spot size empowers users to have a good judgement on the zone of deposited energy in the tested device. Potential pitfalls such as the laser beam spill phenomenon, which arises from the common use of pulse pickers, are highlighted. This work underlines the continuous need to implement new schemes in order to improve the stability or repeatability of pulsed laser SEE tests, especially in anticipation of smaller test structures from emerging microelectronic devices. In these new implementations, it is also important that dosimetry methods or characterization (though dull but non-trivial due to the wide variety of existing methods) of the laser setups were done accurately in order to allow comparison of laser SEE results moving forward.