Sputtered spring films with low stress anisotropy
US7172707B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 5, 2005 |
| Grant date | Feb 6, 2007 |
| Priority date | — |
| Expiry date | May 13, 2025 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/24
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Methods are disclosed for fabricating spring structures that minimize helical twisting by reducing or eliminating stress anisotropy in the thin films from which the springs are formed through manipulation of the fabrication process parameters and/or spring material compositions. In one embodiment, isotropic internal stress is achieved by manipulating the fabrication parameters (i.e., temperature, pressure, and electrical bias) during spring material film formation to generate the tensile or compressive stress at the saturation point of the spring material. Methods are also disclosed for tuning the saturation point through the use of high temperature or the incorporation of softening metals. In other embodiments, isotropic internal stress is generated through randomized deposition (e.g., pressure homogenization) or directed deposition techniques (e.g., biased sputtering, pulse sputtering, or long throw sputtering). Cluster tools are used to separate the deposition of release and spring materials.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.