Dimensional variation and roughness of LIGA fabricated microstructures

摘要

We have measured the dimensional variation and sidewall roughness of features on PMMA micro- components fabricated by deep x-ray lithography in order to assess the effect of dimensional variation on subsequent assembly operations. Dimensional measurements were made using a stylus profilometer with a repeatability in step height of better than 0.01 (mu)m. Roughness measurements were made with the same profilometer scanning in a direction perpendicular to the length of the parts. 22 (mu)m and 54 (mu)m features exhibited dimensional variations described by a Gaussian distribution with standard deviations of 0.202 (mu)m and 0.381 (mu)m, respectively. This corresponds to a maximum relative variation of between 0.6% and 0.9%. Sidewall roughnesses were found to be in the range of 0.02 (mu)m to 0. 03 (mu)m, an insignificant contribution to the total variation when compared to overall dimensional variation. Several potential sources of this variation are discussed, but no single cause was identified as the source of the significant dimensional variation observed here.