National Semiconductor Corporation

Joost J Vlassak

Vassili M Kitch

Kevin Carl Brown

A process for manufacturing metallic interconnect lines of low stress. Process steps according to the present invention first include a step of providing a semiconductor substrate (e.g. a silicon wafer) with an overlying insulating layer, followed by forming a multi-layer stack on the insulating layer. The multi-layer stack includes at least two adjoining layers: one being a metal M layer (for example an aluminum layer) and the other being a material Q layer, where material Q is a material that forms either (i) an electrically conductive intermetallic layer, or (ii) an electrically conducting solid solution layer, with metal M when subjected to the subsequent thermal treatment step. Silicon and titanium meet this requirement when metal M is aluminum. The multi-layer stack is then pattered to form a multi-layer metallic interconnect line. An interconnect dielectric material layer (e.g. a SiO,or silicon nitride layer) is subsequently formed at a temperature T,, covering the multi-layer metallic interconnect line. The multi-layer metallic interconnect line and the interconnect dielectric material layer are then thermally treated at a temperature T,that is greater than T,, in order to reduce the stress (i.e. compressive or tensile) of the multi-layer metallic interconnect line by forming the electrically conductive intermetallic layer or electrically conductive solid solution layer. The result is a low stress metallic interconnect line.

Method for manufacturing low stress metallic interconnect lines for use in integrated circuits

A method for determining the temperature of a wafer during processing is disclosed. A test wafer is specially prepared in conjunction with a calibration chart. The difference in stack sheet resistance of the test wafer before and after processing is plotted onto the calibration chart to determine the temperature of the test wafer during processing.

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Palo Alto, CA, United States of America

Joost J Vlassak