Lithographic Technique for Imperfect Patterns
Original Publication Date: 1986-Dec-01
Included in the Prior Art Database: 2005-Mar-09
The use of a scanning laser or other beam to sense previously written patterns, associated with previous integrated circuit or packaging levels, assists in precisely aligning a later level. Timing the gating up and down of the writing or sensing beam power to write or not write gives the required dimensions and alignment needed for patterning large areas of elements, such as in thin film transistor liquid crystal displays. The figure shows an exemplary way that the self-learning technique is employed. The gate lines are vertical, and the horizontal source lines are omitted for clarity. Also, not shown, are the transparent electrode pads which are to be connected to the drains.