The development of laser chemical vapor deposition and focused ion beam methods for prototype integrated circuit modification

Abstract

<div lang="en" class="abs"><p class="abs_header">Abstract</p><p>In this work the LCVD of copper and nickel from the precursor gases Cu(hfac)tmvs and Ni(CO)₄ has been investigated. The in-house constructed LCVD system and processes and the practical utilisation of these in prototype integrated circuit edit work are described. The investigated process parameters include laser power, laser scan speed, precursor partial pressure and the effect of H₂ and He carrier gases. The deposited metal conductor lines have been examined by LIMA, AFM, FIB secondary electron/ion micrography, and by electrical measurements.</p><p>Furthermore, the study of experimental FIB circuit edit processes is carried out and discussed with particular emphasis on ion beam induced ESD damages. It is shown how the LCVD and FIB methods can be combined to create a novel method to carry out successfully circuit edit cases where both methods alone will fail. The combined FIB/LCVD- method is shown to be highly complementary and effective in practical circuit edit work in terms of reduced process time and improved yield. Circuit edit cases where both technologies are successfully used in a complementary way are presented. Selected examples of some special circuit edit cases include RF- circuit editing, a high resolution method for FIB-deposited tungsten conductor line resistance reduction and large area EMI shielding of IC surfaces. Based on the research it was possible for a formal workflow for the combined process to be developed and this approach was applied to 132 circuit edit cases with 85% yield. The combined method was applied to 30% of the total number of edit cases. Finally, the developed process and constructed system was commercialized. </p></div>