Verifying the Structural Quality of the Glassivation Layer
- Posted by Francisco Javier Aparicio Rebollo
- On February 21, 2021
- 0
Glassivation Layer
This test is performed to verify the structural quality of the glassivation layer in aluminum metalized semiconductor devices or microcircuits. The glassivation layer is a deposited dielectric film (e.g., CVD, sputtered of electron beam evaporated glass or nitride, etc.) and its good condition is essential to avoid such problems as electromigration.
General view of a die
The sample is immersed in an aluminum etching solution, in accordance with MIL-STD-883 TM 2021. After etching, the final optical inspection at high magnification is performed using a scanning electron microscope. If the glassivation layer has no defects, no damage in the metallized device will be observed. The metal being etched will mean that the glassivation layer is either flawed or not duly protective and may lead to a failure.
Lot rejection shall be based on the appearance of etched aluminum at any location other than along the edges immediately adjacent to intentionally unglassed areas (e.g., bonding pads, die edge, scribe line, etc.) as shown on figures 2021-1 to 2021-7 of MIL-STD-883, method 2021.
Defective glassivation
The defects detected in the glassivation layer shall be categorized as follows:
- Missing glassivation over aluminium (figure 2021-1 of MIL-STD-883 method 2011)
- Cracks in glass over aluminium (figure 2021-2 of MIL-STD-883 method 2011)
- Cracks in glass or improper glass coverage along edge of aluminium (figure 2021-3 of MIL-STD-883 method 2011)
- Pinholes in glass on top surface and edges of aluminium (figure 2021-4 of MIL-STD-883 method 2011)
Standar Test PDF File
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Since 2007 Dr. Aparicio has developed a productive research career within the field of Materials Science including post-doctoral stays at the University of Trento, the University of Mons, and the Spanish National Research Council (CSIC). His researches have been published in more than 30 articles in reputed international research journals and conferences (> 70) including more than 10 invited talks and lectures.
Within the frame of the program “Torres Quevedo” for the Knowledge Transfer and the incorporation of research talent into the industry, in 2019 he joined Alter Technology as Senior Materials Science Test Engineer. In 2019 he was appointed to lead the Scanning Acoustic Microscopy Service. Within this framework, he currently collaborates in different ESA projects (JUICE and PLATO).”
Actually, he is not in our company anymore, but still as an external collaborator in our blog.
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