Evaluating a multi-layered structure for voids
AssigneeApplied Materials, Inc.
InventorsPeter G. Borden, Ji-Ping Li
Life of this patent
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Abstract
A method and apparatus measure properties of two layers of a damascene structure (e.g. a silicon wafer during fabrication), and use the two measurements to identify a location as having voids. One of the two measurements is of resistance per unit length. The two measurements may be used in any manner, e.g. compared to one another, and voids are deemed to be present when the two measurements diverge from each other. In response to the detection of voids, a process parameter used in fabrication of the damascene structure may be changed, to reduce or eliminate voids in to-be-formed structures.
Claims20
A method for evaluating a structure that has a plurality of layers, the method comprising:
- measuring a first property of a first layer in the structure, to obtain a first measurement;
- measuring a second property of a second layer in the structure, to obtain a second measurement;
- and
- using the first measurement and the second measurement to determine existence of a void;
- wherein the first layer comprises a plurality of traces of conductive material supported by the second layer;
- wherein the measuring of first property is performed across a group of traces, thereby to obtain in the first measurement an average measure of the first property across traces in the group;
- wherein the measuring of first property comprises illuminating the structure with a beam comprising electromagnetic radiation having a wavelength greater than a pitch between two adjacent traces in said group;
- and
- wherein the first property is resistance per unit length of said traces.
Dependencies are inferred from the claim text.