Process for NiFe fluxgate device
US10266950B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 10, 2017 |
| Grant date | Apr 23, 2019 |
| Priority date | — |
| Expiry date | Nov 10, 2037 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/02107
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
An etchant for simultaneously etching NiFe and AlN with approximately equal etch rates that comprises phosphoric acid, acetic acid, nitric acid and deionized water. Alternating layers of NiFe and AlN may be used to form a magnetic core of a fluxgate magnetometer in an integrated circuit. The wet etch provides a good etch rate of the alternating layers with good dimensional control and with a good resulting magnetic core profile. The alternating layers of NiFe and AlN may be encapsulated with a stress relief layer. A resist pattern may be used to define the magnetic core geometry. The overetch time of the wet etch may be controlled so that the magnetic core pattern extends at least 1.5 um beyond the base of the magnetic core post etch. The photo mask used to form the resist pattern may also be used to form a stress relief etch pattern.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.