Patent ID: 7169626
Filing Date: 2007-01-30
Classification: H01L

Abstract:
1. A method for adjusting semiconductor processing equipment, comprising: providing a lot of product wafers, wherein each of the product wafers has a plurality of alignment marks, and each alignment mark has a mark center; providing a test wafer having the same size and shape as the product wafers, wherein a plurality of test centers are defined on the test wafer, and the test centers have the same location on the test wafer as the mark centers on the product wafers; providing a clamp ring having shielding tabs, wherein the clamp ring holds the test wafer so that the shielding tabs cover the test centers; depositing a layer on the test wafer; removing the clamp ring from the test wafer; determining whether a first, a second and a third point are covered by the layer, wherein all the first, second and third points are separated from a first test center by a critical interval, the first point is located on a first diameter between the center of the test wafer and the first test center, and the second and third points are located at either side of a first line perpendicular to the first diameter passing through the test center; taking corrective action if any of the first, second and third points is covered by the layer; determining whether the fourth point, a fifth point and a sixth point are covered by the layer, wherein all of the fourth, fifth and sixth points are separated from a second test center by the critical interval, the fourth point is located on a second diameter between the center of the test wafer and the second test center, and the fifth and sixth points are located at either side of a second line perpendicular to a second diameter passing through the second test center; taking corrective action if any of the fourth, fifth and sixth points is covered by the layer; and processing the lot of product wafers if the first, second, third, fourth, fifth and sixth points of the first test wafer are not covered by the layer.