8 March 2016 Triple AIM evaluation and application in advanced node
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Abstract
A novel method on advanced node for IBO (Image Based Overlay) data extraction accuracy is demonstrated in this work, and here some special design in triple-AIM (Advanced Imaging Metrology) is able to realize the approach.

Since triple AIM design has 3 locations left for patterning layers insertion, a new design with 2 layers locations, location-A (inner) and location-B (middle), are generated by 1st pattering, i.e. once lithography exposure, and the 2 marks grouping are formed on dielectric through lithography and etching process with a predetermined overlay "zero offset" through original mask layout design, as illustrated in Fig. (1).

And then, as following top photo resist layer, assumed location-C (outer), lithography patterning process, PR coating, exposure and development complete, full triple-AIM patterns is generated, and 3 sets of overlay data could be obtained, A to B, C to B, C to A.

Through re-calculating the overlay raw data of current (2nd patterning layer) to previous (1st patterning layer) layer by averaging [C to B] and [C to A], then theoretically the data extraction of sites would be more accuracy, since the variation of local marks signal, induced by inline process instability, could be minimized through the raw data averaging procedure.

Moreover, from raw data [A to B], an extra monitor function for detections of the inline process variation, marks selection and recipe setting optimization could be obtained, since marks in [A] and [BB] locations are both generated in 1st patterning, and with the target "zero".

So if the raw data [A to BB] is bigger or smaller than "zero" in some degree, there should be some process issue or marks condition setting error in triple-AIM design.
© (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Gary Ch. Wang, Gary Ch. Wang, En Chuan Lio, En Chuan Lio, Yuting Hung, Yuting Hung, Charlie Chen, Charlie Chen, Sybil Wang, Sybil Wang, Tang Chun Weng, Tang Chun Weng, Bill Lin, Bill Lin, Chun Chi Yu, Chun Chi Yu, } "Triple AIM evaluation and application in advanced node", Proc. SPIE 9778, Metrology, Inspection, and Process Control for Microlithography XXX, 97782U (8 March 2016); doi: 10.1117/12.2219501; https://doi.org/10.1117/12.2219501
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