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Product briefing outline: ISIS sentronics has launched the SemDex 300 series wafer metrology system, that is designed to provide user defined thickness maps of substrates or other (multiple-) layers (for e.g. SOI) at repeatable rates down to 50nm. A wide range of materials including silicon, GaN, GaAs, SiC, Glass, Potoresist etc...can be evaluated, ranging from minimum 3-5µm up to about 1000µm. Other features such as bow/ warp, flatness, and wafer stress are also performed as well as surfacing profiling for mini-bumps can be achieved by exchanging the sensor head.

Problem: Semiconductor substrates are getting increasingly thinner for various physical and technical reasons. Total thickness variations of 1 µm or even less is the new benchmark for many processes, especially for wafer to wafer uniformity for leading edge lithography requirements. In the MEMS field, high lateral definition is another challenge.

Solution: The SemDex 300 series incorporates the ISIS patented SCI "Spectral coherence technology" platform which combines in a unique way, very high precision 50nm repeat-rate and better than 200nm absolute accuracies at data acquisition rates of up to 4000/s. The small spot size of  5-20 µm (depending on the thickness range) permits thickness data to the very edge of structures.

Applications: Mainly evaluation of thickness data of substrate grinding, either off-line with the SemDex 301 wafer inspection tool, or on-line during grinding with the incorporated StraDex sensor. Membranes or other etched features in MEMS structures.

Platform: The SemDex 300 series and StraDex sensors are based the high-throughput ISIS firmware, according to the company. The operations software works on the Microsoft XP or 2000 platform and contains optionally SECS/GEM extension capabilities.

Availability: April 2006 onwards.