- Title Information
- Title
- Numerical Simulation of Stress Generation and Whisker Growth in Sn Films
- Name:
Personal
- Name Part
- Buchovecky, Eric Jon
- Role
- Role Term:
Text
- creator
- Origin Information
- Copyright Date
- 2010
- Physical Description
- Extent
- xx, 131 p.
- digitalOrigin
- born digital
- Note
- Thesis (Ph.D. -- Brown University (2010)
- Name:
Personal
- Name Part
- Bower, Allan
- Role
- Role Term:
Text
- Director
- Name:
Personal
- Name Part
- Kumar, Sharvan
- Role
- Role Term:
Text
- Reader
- Name:
Personal
- Name Part
- Guduru, Pradeep
- Role
- Role Term:
Text
- Reader
- Name:
Corporate
- Name Part
- Brown University. ENGINEERING: Solid Mechanics
- Role
- Role Term:
Text
- sponsor
- Genre (aat)
- theses
- Abstract
- The spontaneous growth of long, filamentary whiskers from the surface of Sn-plated Cu conductors poses a serious threat to the reliability of electronic components. While it is generally accepted that whiskers form to relax compressive stress generated by the localized growth of Cu6Sn5 intermetallic compound (IMC), the mechanisms are not fully understood. In this work, finite element analysis (FEA) is used to quantitatively assess the interactions among parallel mechanisms of stress generation and relaxation, and determine how they control whisker growth. The FEA model includes growth of an IMC phase, elastic and plastic deformation within the Sn grains, and stress-driven diffusion along grain boundaries, all of which are indicated by experimental evidence. FEA results reveal that plastic yield within Sn grains coupled with stress-driven grain boundary diffusion effectively transmits stress through the Sn and, significantly, can account for the experimentally measured stress evolution without relaxation due to whisker growth. In addition, the columnar microstructure of the Sn, presence of surface oxide and non-planar IMC morphology are all found to be necessary for stress build-up, suggesting that processing or treatment that disrupts these features will reduce the stress level in the Sn. Modeling also indicates previously unrecognized kinetic relations governing whisker growth, including the emergence of two kinetic regimes controlled by the balance between strain generation and relaxation. In one regime whiskers dominate relaxation and whisker velocity scales directly with IMC growth rate, in the other, multiple competing mechanisms relax strain and whisker velocity varies weakly with IMC growth rate. A mathematical model is presented to describe these kinetic relations.
- Subject
- Topic
- lead-free
- Subject
- Topic
- Sn
- Subject
- Topic
- whisker
- Subject
- Topic
- grain boundary diffusion
- Subject
- Topic
- finite element
- Subject
- Topic
- FEA
- Subject
- Topic
- FEM
- Subject (FAST)
(authorityURI="http://id.worldcat.org/fast", valueURI="http://id.worldcat.org/fast/987860")
- Topic
- Kirkendall effect
- Record Information
- Record Content Source (marcorg)
- RPB
- Record Creation Date
(encoding="iso8601")
- 20111003
- Language
- Language Term:
Code (ISO639-2B)
- eng
- Language Term:
Text
- English
- Identifier:
DOI
- 10.7301/Z00C4T1R
- Access Condition:
rights statement
(href="http://rightsstatements.org/vocab/InC/1.0/")
- In Copyright
- Access Condition:
restriction on access
- Collection is open for research.
- Type of Resource (primo)
- dissertations