Department of Engineering

PhD in: MEMS (MicroElectroMechanical Systems) Tribology and Bonding

Principal Investigator:
Michael Sutcliffe

Project Details:
MEMS devices are being realised in a wide range of applications. However there are serious concerns about manufacturing routes for such devices. MEMS technology requires planarization and polishing of a variety of material so that chemical-mechanical polishing (CMP) and subsequent bonding are becoming significant MEMS processes. CMP works through the chemically-assisted wear of the wafer surface by slurry particle and pad contact. There are several aspects of the mechanics of this process that are tribologically counter-intuitive, and which this project will address. Hydrodynamic effects due to the texture of the polishing mat interact with macroscopic 'wedge' effects to generate pressure distributions across the wafer so that establishing the separation of the wafer from the polishing medium is not straightforward. An important application of CMP has been to produce "flat" surfaces sufficient to enable wafer bonding. Enough surface-to-surface contact has been achieved for some locations on the wafer and for large enough structures for bonding to be demonstrated. Because CMP does not achieve "flatness" across entire chips or uniformly across the entire wafer, serious concerns remain.

Background Required:
Applicants should have a 1^st or 2.1 in Engineering or a related subject.

Funding Source:
An EPSRC CASE Studentship is likely to be available for UK students, otherwise must be self-funded. Some "top-up" funding may be available.

Research Groups Involved:

• Tribology
• Micromechanics

Application Deadline:
Open

For further information and to apply contact:

Initial letters of application and CVs should be sent to Dr. Sutcliffe.

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