A method of etching a contact hole etched into an insulating layer with tungsten in a manufacturing process of a semiconductor integrated circuit

摘要

In filling contact holes (3) in insulating layers (2) of integrated semiconductor circuits, the tungsten metal layer (4, 5) deposited over the entire substrate (1) is covered with an auxiliary layer (6) of organic material and the organic auxiliary layer (6) is anisotropically etched down to the tungsten surface (5). The tungsten layer (4, 5) is then selectively etched back to the insulating layer (2) and finally the residual layer (6a) of the organic material in the contact hole region (3) on the tungsten plugs (5a) is selectively removed. In this way, contact holes (and also via holes) 1 mu m and less in diameter can be reliably filled with tungsten and ensure a good edge coverage during the subsequent metallisation processes. The contacts can be loaded with high current densities. The method is used to produce multilayer interconnections in highly integrated circuits. IMAGE