Calibration and alignment target plate

A chuck-mountable optical calibration and alignment plate for use with wafer dicing means controlled by microscopic auto-alignment means comprising:

• center line rulings intersecting at right angles for calibration of rotational accuracy;
• at least one pair of coplanar checkerboard regions of alternating reflective and non-reflective sections for calibration and alignment of control optics elements;
• and
• at least one pair of coplanar reflective regions for calibration of microscopic optical lighting distribution.

A method of recalibrating automatic wafer dicing means to compensate for inherent errors introduced by stepping control systems comprising:

• providing a calibration plate, having plurality of coplanar precision rulings thereon spaced apart by a given increment, on the wafer supporting chuck;
• initially aligning the dicing edge of said wafer dicing means with one of said rulings and then stepping said dicing edge a predetermined number of said increments along the rulings according to said stepping control system;
• determining the stepping control system error, as defined by the difference between the actual posititon of said dicing edge along the rulings and the desired position, as indicated by moving said predetermined number of said increments from the initially aligned ruling;
• and
• readjusting said stepping control system so as to compensate for said error.

A method of recalibrating automatic wafer dicing means, having optical elements which define a microscopic operating field of view and a wafer supporting chuck in said operating field of view, comprising:

• positioning a target plate, having a plurality of coplanar optical targets, on said wafer supporting chuck;
• locating said optical elements with respect to said wafer supporting chuck such that said operating field of view is directed onto a first reflective region of said optical targets, and adjusting said optical elements to define even illumination over said field of view;
• and
• relocating said optical elements with respect to said wafer supporting chuck such that said operating field of view is directed onto a second, checkerboard pattern of alternating reflective and non-reflective regions of said optical targets, and adjusting said optical elements to improve focus and minimize distortion over said field of view.

A method of aligning a support surface with respect to a microscopic operating tool and optically calibrating a microscopic field of view for optical elements controlling said operating tool, comprising:

• positioning a target plate on said support surface, said target plate having a plurality of spaced apart uniformly reflective portions and a plurality of spaced apart checkerboard portions of alternating reflective and non-reflective regions, and said optical elements including binocular image splitter means;
• locating said optical elements with respect to said support surface such that said plurality of reflective positions is aligned with the field of view of said binocular image splitter means, and adjusting said optical elements and orientation of said support surface to define even illumination over said field of view;
• and
• locating said optical elements with respect to said support surface such that said plurality of checkerboard portions is aligned with the field of view of said binocular image splitter means, and adjusting said optical elements and orientation of said support surface to minimize distortion over said field of view.