Patent ID: 7141368

Claim:
A method of fabricating multiple chemical arrays on a substrate, wherein: each array of the multiple chemical array has multiple rows of features, wherein the features are separated from each other by inter-feature areas; the multiple chemical arrays are separated from each other by inter-array areas, wherein the inter-array areas are of greater width than the inter-feature areas; and the multiple chemical arrays are arranged in sets where the arrays of different sets are arranged in an orthogonal orientation with respect to the rows; the method comprising dispensing drops onto the substrate from a drop dispensing head positioned such that a gap is maintained between the head arid the substrate while moving the head and substrate relative to one another along a bi-directional path so as to fabricate the arrays, wherein the bi-directional path for the relative moving comprises: (a) moving the head in a direction along the rows of a first array set; (b) then moving the head in an opposite direction along the rows of a second array set without intervening movement of the head in the opposite direction over all of the first array set; and (c) repeating (b), with the second array set of an earlier cycle being the first array set of a later cycle; wherein between movements in the opposite directions, the dispensing head is displaced in a sideways orientation between one array set and the next and a majority of the rows in arrays within a set are dispensed while the head is moving in a same direction along the rows.