Nanoscale Wear Tribometer

ASML is one of the world’s leading manufacturers of semiconductor fabrication equipment, on which companies such as Samsung, Apple, NVIDIA, and more rely for production. The company’s lithography machines can etch high-precision circuits onto silicon wafers with features as small as 2 nanometers. Within the lithography process, silicon wafers are placed on tables, etched, and removed at rates of up to 400 per hour and accelerated up to 7 Gs or 30 Gs in deep- or extreme ultraviolet lithography, respectively . This rapid cycling creates a mechanical wear condition between the wafer surface and the table. During the reworking process of the wafer table, where the parallelism is out of tolerance, the table’s diamond-like carbon (DLC) ceramic coating engages with a silicon carbide ceramic (SiSiC) tooling surface. During this reconditioning process, the inclusion of any particles (third bodies) can induce another form of wear, further reducing machine performance and parallelism, and result in a costly repair cycle. By characterizing this wear rate, ASML can optimize preventative maintenance and relating tooling, reducing machine downtime and expensive repairs. 

Tribometers are scientific instruments that are used to perform wear and friction characterizations of two surfaces in contact. The amount of wear in a system depends on several system factors such as applied load, machine characteristics, sliding speed, sliding distance, the environment, and various material properties [ ASTM-G99-17]. A typical tribometer features a driven spindle and chuck for holding the revolving sample (shaped like a disc), a lever-arm device to hold the pin, and attachments to allow the pin specimen to be forced against the revolving disk specimen with a controlled load [ ASTM-G99-17]. By including displacement sensors, tribometers can measure changes in depth with respect to time (wear rates). 

The goal of this design capstone is to develop a LabVIEW-integrated tribometer, with a nanoscale depth-resolution of at least 40 nanometers and a controllable wear track system to characterize flat-on-flat wear contact of diamond-like coatings (DLCs) for ASML.    

We completed the design of an integrated tribometer with 3 nm in-situ depth-sensing resolution, characterized wear under multiple contact conditions, and identified and processed complex signalling in mechanical and electronic hardware!