[CCoE Notice] Master's Thesis Defense Announcement

[Khator, Suresh]

M.S Thesis Defense Presentation
Scale up of the process for Electrodeposition of low stress Permalloy film
Rachit Sharma, MSIE Candidate

Advisor: Dr. Ali Kamrani and Co-Advisor: Dr. Stanko Brankovic
April 21st 2011, at 2:30 pm, Industrial Engineering Conference Room

Abstract
Soft high magnetic moment alloys are used in production of magnetic recording heads and MEMS devices. Permalloy (Ni-80%, Fe-20% by weight), is a commonly used soft magnetic material in MEMS because of its high magnetic permeability, low coercivity, and near zero magnetostriction. During electrodeposition of Permalloy, residual stress is an undesired parameter which may cause effects such as delamination and cracks, affecting the working of the MEMS device.

In this project we have developed an electrodeposition bath which deposits Permalloy with low stress, desired magnetic properties and high corrosion resistance. We met the challenge of electrodepositing Permalloy on six inch wafer using 25 L of solution, meeting the industrial level requirement and producing films with the required composition, low stress and susceptibility to corrosion. We used Semitool-M-Raider Series tool to electroplate Permalloy on copper sputtered silicon wafers and studied the effects of parameters like flow rate, agitation velocity, agitation acceleration, etc on electrodeposition of Permalloy. We optimized each parameter respectively, to get rid of the standing wave seen on the initially plated wafers.  We studied the variation in anode potentials, which affects the uniformity of deposition, to obtain the alloy with most uniform thickness. The residual stress in these electroplated wafers was measured using wafer bow measurement. The next step involves using the same scale up process to measure residual stress on different alloys and patterned wafers.

_______________________________________________________
Suresh K. Khator, Ph.D., P.E.                         Phone: 713-743-4205
Associate Dean, College of Engineering    Fax: 713-743-4214
University of Houston                                     Email: skhator at uh.edu
E421 Engineering Bldg 2                                www.egr.uh.edu/ie
Houston, TX 77204-4008

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://Bug.EGR.UH.EDU/pipermail/engi-dist/attachments/20110407/6110c853/attachment.html