Severe technical challengesbottlenecks to quality monitoring, especially in critical dimensional measurement for vias below 1 micrometer are currently faced in advanced packaging. To break through the bottleneck, broadband deep-ultraviolet light (DUV) is proposed to develop a novel optical system, so the optical wave can penetrate through the test structure effectively. More importantly, the proposed optical approach based on reflectometryscatterometry is integrated with novel AI machine-learning optimization to achieve the best multi-CD measurement. As proved by industrial via tests, the method is capable of measuring CDs of submicron viasRDL, which is regarded as the best measuring specification in the world.

"Benchmarking between first-tier makersthe developed technology:
 
  There are currently four first-tier major makers for semiconductor advanced packaging, such as KLA (KLA Kronos™ 1190) 、Bruker (Bruker FilmTek 200M TSV)、FormFactor (FormFactor MicroProf® AP) 、Takano Co.LTD. in the world. From a comprehensive review of their latest machine models for ViasRDL optical CDs measurement, it is clearly concluded that all their latest models are limited to a minimum opening diameter of 1.0 micrometer with a maximum aspect ratio of 3. In comparison with these solutions, our developed solution provides a minimum opening diameter of 0.3 micrometer with a maximum aspect ratio of up to 15maximum measurement uncertainty of less than 50 nm.

The developed technology has attracted two first-tier semiconductor vendors to establish two technical teams by combining three first-tier equipment makers (Chroma electronics, GPM,Young Optics)four universities (NTU, NTUST, NTUT,NYCU) under the support of the AOIEC (Automated Optical Inspection Equipment Coalition) in NTU. The research team led by AOIEC has formally signed R/D cooperation contracts with the three vendors to fasten the implementation of the industrial-level solutions based on the prototype systemtechniques developed by the university team. The AOIEC can strongly support the development of the developing solution capable of delivering industrial-level applications.