Quick Scan Position Locator System for Laser Trimmer Systems
Original Publication Date: 1988-Sep-01
Included in the Prior Art Database: 2005-Feb-15
A laser scanning system automatically locates the correct laser trimmer start and stop positions for the accurate trimming of CERMET and paste type resisters. The system works as described in the following. Positional errors can occur in any one or a combination of at least four planes of interest (Fig. 1). The planes consist of a laser lens plane 1, a circuit metallization plane or component wiring plane 2, which is on a substrate 3, and a substrate holder plane 4. When all four planes are perfectly aligned, a laser beam 5 is positioned over a resistor 6 in the layout plane 2. The beam 5 vaporizes (trims) the resistive material of resistor 6 until the proper value is obtained. If every plane is correctly aligned in the X-Y-Z-r directions with respect to vertical reference 7, there are no error sources.