Post etch overlay metrology to avoid absorbing layers preventing measurements
AssigneeAdvanced Micro Devices, Inc.
InventorsCyrus E. Tabery, Christopher F. Lyons, Srikanteswara Dakshina-Murthy
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Abstract
A method of determining overlay layers utilizing advanced lithographic materials utilizes a post-etch overlay metrology. After etching, a relatively opaque layer is removed so that registration markers such as trench isolation structures can be observed. Lithographic parameters associated with the process can be adjusted in accordance with the observations. In a preferred embodiment, an overlay error is determined and adjustments are made to the reduce the overlay error.
Claims20
A method of processing integrated circuits, the method comprising:
- lithographically patterning a photoresist layer above a layer including carbon to form a patterned photoresist layer, the layer including carbon being above an underlying layer or substrate including features;
- etching the layer including carbon in accordance with the patterned photoresist layer;
- etching the underlying layer or substrate;
- removing the layer including carbon;
- observing the features to determine at least one error factor;
- and
- adjusting lithographic parameters in accordance with the at least one error factor.
A method of patterning a gate stack above a substrate using a patterned carbon layer, the method comprising:
- patterning the gate stack in accordance with the patterned carbon layer;
- removing the patterned carbon layer;
- and
- determining a lithographic error using optical equipment, the optical equipment determining a location of features on the substrate to determine the lithographic error.
A method of fabricating an integrated circuit above a substrate including trench isolation structures, the method comprising steps of:
- patterning a photoresist layer above a layer including carbon to form a patterned photoresist layer, the layer including carbon being above an underlying layer above the substrate, the underlying layer being translucent;
- etching the layer including carbon in accordance with the patterned photoresist layer;
- etching the underlying layer, the underlying layer covering at least a portion of the trench isolation structures;
- removing the layer including carbon;
- locating positions of the trench isolation structures to determine an overlay error;
- and
- adjusting lithographic parameters in accordance with the overlay error.
Dependencies are inferred from the claim text.