This paper demonstrates the utilization of the C-AFM to study and identify the electrical characteristic of SRAM high resistance failure in CMOS process. After taking electrical measurement, cross-section TEM together with CD measurement to reveal and understand the physical root cause of the electrical failure is reported.

The application of the conductive atomic force microscope (C-AFM) has been widely reported as a useful method of failure analysis in semiconductor field of nanometer scale science and technology, [1] Especially for hard failure and soft failure identification and localization at logic and SRAM in CMOS process. This paper will demonstrate a new application of the C-AFM to identify the electric characteristic of SRAM soft failure in CMOS process. After taking electrical measurement, plain view SEM and cross-section TEM will reveal and understand the physical root cause of the electrical failure. After that, the principle of application for C-AFM on this SRAM soft failure analysis will be discussed.

The upward trend in memory to chip ratio in novel chip design had increase the possibility of a defect to fall on the memory area. There are a number of ways of performing memory address verification in the industry. This paper describes some of the methodologies as well as introduces an efficient approach using near infra-red (NIR) laser to perform the memory address verification. Current methodologies include analyzing physical chip with memory hard failure, the green laser (532nm) method, and the focus ion beam method. The advantages and disadvantages of each methodology are mentioned. As long as the failing orientation is correct and the test program failing address is within the NIR laser damage zone, a failure analyst can have more confidence to analyze a real chip with memory failure without any doubt that he/she might be looking at the wrong location.

No abstract

No abstract