SUBJECT: Ph.D. Proposal Presentation
BY: Jamil Ahmad
TIME: Wednesday, March 5, 2008, 1:00 p.m.
PLACE: MARC Building, 201
TITLE: Development of Thin Film Interfacial Fracture Testing Technique using an Intrinsically Stressed Electroplated Metal Layer
COMMITTEE: Dr. Suresh Sitaraman, Chair (ME)
Dr. Samuel Graham (ME)
Dr. Olivier Pierron (ME)
Dr. Ken Gall (MSE)
Dr. Jud Ready (MSE/GTRI)


Microelectronic devices and Micro-Electro-Mechanical-Systems (MEMs) consist of layers of thin films made of dissimilar materials. Interfacial fracture between thin films is a concern for the reliability of these devices. Measurement of the interfacial fracture toughness between thin films is essential for the reliable design of microelectronic devices and MEMs. However, available fracture toughness test methods have several shortcomings, when they are used for thin film testing. Some require extensive processing; some require fixturing and loading; some cannot be applied to thin films; some create excessive plastic deformation; some of the tests do not yield to simple data reduction; some cannot be applied to strong interfaces; and some require artificial release layers placed between the layers of interest. Given these shortcomings, this thesis aims to develop a fixtureless, superlayer-based interfacial fracture toughness test that does not require a release layer and that uses a well-controlled electroplating process to drive the interfacial delamination. The developed test technique will be demonstrated using electroplated stressed chromium layer deposited on top of blanket layers of low-k black diamond dielectric as well as blanker layers of metal films on Si substrate. The proposed test technique uses a thickness gradient of the electroplated layer to gradually vary the amount of energy available for interfacial crack propagation. With the decreasing super layer thickness, the interfacial crack will cease to propagate when the energy available for crack propagation is equal to the interfacial fracture toughness. Thus, the interfacial fracture toughness of the interested interface can be determined by the location at which the interfacial delamination stops. Several test cases will be demonstrated and the interfacial fracture toughness values and mode mixity values will be reported.