Process for forming sub-lithographic photoresist features by modification of the photoresist surface
AssigneeAdvanced Micro Devices, Inc.
InventorsJeffrey A. Shields, Uzodinma Okoroanyanwu, Chih-Yuh Yang
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Abstract
A process for forming sub-lithographic features in an integrated circuit is disclosed herein. The process includes modifying a photoresist layer after patterning and development but before it is utilized to pattern the underlying layers. The modified photoresist layer has different etch rates in the vertical and horizontal directions. The modified photoresist layer is trimmed with a plasma etch. A feature included in the trimmed photoresist layer has a sub-lithographic lateral dimension.
Claims21
A method of trimming a feature patterned on a photoresist layer, the photoresist layer disposed over a substrate and the feature including a top portion and lateral surfaces, the method comprising the steps of:
- modifying the top portion of the feature patterned on the photoresist layer to form a modified top portion;
- and
- trimming the feature patterned on the photoresist layer to form a trimmed feature, wherein a vertical trim rate and a lateral trim rate are associated with the feature and the vertical trim rate is slower than the lateral trim rate due to the modified top portion.
An integrated circuit fabrication process, the process comprising:
- developing a patterned photoresist layer, the patterned photoresist layer including at least one feature;
- modifying the patterned photoresist layer to form a top portion and a bottom portion of the at least one feature, the top portion having a top etch rate and the bottom portion having a bottom etch rate, wherein the top etch rate is different from the bottom etch rate;
- and
- etching the patterned photoresist layer to change the at least one feature to have a sub-lithographic lateral dimension and a sufficient vertical thickness to maintain pattern integrity.
An integrated circuit having a feature of sub-lithographic dimension, the feature formed by the process comprising:
- patterning the feature on a photoresist layer disposed over a substrate, the feature patterned in accordance with a radiation at a lithographic wavelength and a pattern provided on a mask or a reticle;
- developing the feature patterned on the photoresist layer;
- changing at least a portion of the photoresist layer, wherein a top portion of the feature patterned on the photoresist layer is changed to have a different etch rate from a bottom portion of the feature patterned on the photoresist layer;
- trimming the feature patterned on the photoresist layer to a sub-lithographic dimension;
- and
- transferring the trimmed feature patterned on the photoresist layer to the substrate, wherein the feature in the substrate has the sub-lithographic dimension.
Dependencies are inferred from the claim text.