Browse Prior Art Database

SEMICONDUCTOR LEAD SCANNER

IP.com Disclosure Number: IPCOM000006100D
Original Publication Date: 1991-Apr-01
Included in the Prior Art Database: 2001-Dec-04
Document File: 1 page(s) / 54K

Publishing Venue

Motorola

Related People

Akinori Ishimoto: AUTHOR

Abstract

The lead scanner of Figure 1 eliminates multiple steps when determining if the leads on finished semiconductor devices have been bent beyond a given margin of error or are improperly spaced.

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MOmROLA INC. Technical Developments Volume 12 April 1991

SEMICONDUCTOR LEAD SCANNER

by Akinori lshimoto

   The lead scanner of Figure 1 eliminates multiple steps when determining if the leads on finished semiconductor devices have been bent beyond a given margin of error or are improperly spaced.

  A semiconductor device 10 is placed on a X-Y table 12 in line with a scanner, which may be for example a TV camera 14 and light source 15. The picture taken by the scanner is then magnified and displayed on a screen 16 as indicated in Figure 2. At this level of magnification, only one lead can be viewed on the screen at a time. Therefore, after the distance from the bottom of the lead to the X-Y table has been measured, the device must be moved to measure subsequent leads.

  Before a second lead is viewed on the screen, however, the central axis 18 of the presently viewed lead is determined. This central axis is aligned with a

predetermined vertical line 20 on the screen (Figure
2). A linearly scaled plunger 22 of Figure 1 is used to move the X-Y table, thus moving the semiconductor device about. Each location of the device and each movement is accurately recorded. Therefore, the location of the central axis 18 of the lead when aligned with the vertical line 20 is recorded.

  A subsequent lead is next moved into the view of the scanner. The precise distance which the table moves is determined by the linearly scaled plunger 22. The distance from the bottom of this next lead...