Method for reducing time to place a tool onto a workpiece
US5121870A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 29, 1991 |
| Grant date | Jun 16, 1992 |
| Priority date | — |
| Expiry date | Apr 29, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/19043
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
In bonding a number of pads which may have different heights within a predetermined tolerance the bonding tool (28, 24, 14, 10) is moved in slow speed search mode (70) to contact the first pad (P.sub.1) and store the height (H.sub.1) of the first pad (P.sub.1). After a predetermined amount of continued overtravel (OT.sub.1) the bond is performed and the tool raised. Operations on other pads may occur at this point. The tool is then moved to a point above the location of the second pad. The tool is moved down to the second pad without a search mode but to a second pad target height (H.sub.1 +OT.sub.2) that is the sum of the sensed height of the preceding pad and an overtravel distance. The approach of the tool to the second pad is done at high speed (84,88) and senses and stores the point of contact, or the actual sensed height of the second pad, for use in determining a target height for the high speed approach to the next pad, thereby eliminating the slow speed search required for all pads but the first on a part.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.