This paper discussed on how the importance of failure analysis to identify the root cause and mechanism that resulted in the MEMS failure. The defect seen was either directly on the MEMS caps or the CMOS integrated chip in wafer fabrication. Two case studies were highlighted in the discussion to demonstrate how the FA procedures that the analysts had adopted in order to narrow down to the defect site successfully on MEMS cap as well as on CMOS chip on MEMS package units. Besides the use of electrical fault isolation tool/technique such as TIVA for defect localization, a new physical deprocessing approach based on the cutting method was performed on the MEMS package unit in order to separate the MEMS from the Si Cap. This approach would definitely help to prevent the introduction of particles and artifacts during the PFA that could mislead the FA analyst into wrong data interpretation. Other FA tool such as SEM inspection to observe the physical defect and Auger analysis to identify the elements in the defect during the course of analysis were also documented in this paper.

This paper describes the effectiveness of using light induced Current Imaging – Atomic Force Microscopy (CIAFP) to localize defects that are not easily detected through conventional CI-AFP. Defect localization enhancement for both memory and logic failures has been demonstrated. For advanced technology nodes memory failures, current imaging from photovoltaic effects enhanced the detection of bridging between similar types of junctions. Light induced effects also helped to improve the distinction between gated and nongated diode, as a result enhanced localization of gate to source/drain short.

The case study in this paper describes how collaboration between customer design and test teams and a thorough FAB investigation triggered by a detailed electrical analysis using the Atomic Force Nanoprober (AFP) resulted in the effective resolution of a challenging implant related issue on LDMOS structure that caused yield loss. The quick success in this case has led to a shorter yield ramp cycle on this new product for mass production.

As the rapid developments of semiconductor manufacturing technologies, the CD of the device keep shrinking. The IC devices have a smaller feature sizes and higher densities, and thus there are many challenges come up in terms of the failure analysis and localized device characterization. Besides the challenge of smaller feature size, there is another challenge as well. Some of the traditional FA method can no longer be employed on advanced technologies, such as 28nm and beyond. Quickly and successfully isolating the failed location and obtaining electrical signature of the defect has become more of a challenge, especially for the device level analysis and characterization. AFP nanoprobing system provides some solutions to advanced nodes fault isolation through its AFM imaging mode of CAFM.