Resolving thermoelectric potentials during laser trimming of resistors
US7667159B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 31, 2005 |
| Grant date | Feb 23, 2010 |
| Priority date | — |
| Expiry date | Mar 24, 2028 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB23K2103/52
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
Thermoelectric effects that occur during laser trimming of resistors (20) are resolved by taking voltage measurements. The voltage attributed to laser heating on a resistor (20) during a low-power simulated trim (10) is used to determine a relatively thermal-neutral location (18) on the resistor (20). A trimming-to-value operation can then be performed on all like resistors (20). Voltage measurements can also be taken before and after every pulse in a trimming operation to establish thermal deviation information that can be used to offset the desired trim value against which resistor measurement values are compared. Spatially distant or nonadjacent resistors (20) in a row or column can also be trimmed sequentially to minimize heating effects that might otherwise distort resistance values on adjacent or nearby resistors (20).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.