Lapping a head while powered up to eliminate expansion of the head due to heating
US6857937B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | May 30, 2002 |
| Grant date | Feb 22, 2005 |
| Priority date | — |
| Expiry date | Jan 2, 2023 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/53165
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A head is fabricated using photolithography, and the head is purposely powered up during a material removal process, such as lapping, so that the head's expansion (that would be formed on being powered up during normal usage in a drive) is planarized. Specifically, the head is energized in a manner identical (or similar) to energization of circuitry in the head during normal operation in a drive, even though fabrication of the head has not yet been completed. When energized, a shape that the head would have during normal operation is replicated (or approximated). Therefore, the head's shape includes a expansion of the pole tip region, although the head is only partially fabricated. Thereafter, a portion of the head in the expansion is partially or completely removed, by lapping while energized. The depth of material removal from the head is monitored e.g. by a controller sensitive to a change in electrical characteristic of a device (such as a resistor) that is normally fabricated during photolithography of the head.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.