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US 5,032,233 AGranted
Method for improving step coverage of a metallization layer on an integrated circuit by use of a high melting point metal as an anti-reflective coating during laser planarization
AssigneeMicron Technology, Inc.
InventorsChang Yu, Trung T. Doan, Gurtej S. Sandhu
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Abstract
A method for improving step coverage of metallization layers of an aluminum alloy on an integrated circuit involves use of a deposited layer of a high melting point metal, such as tungsten or an alloy of tungsten and titanium, as an anti-reflective coating (ARC) to increase the efficient use of laser energy for planarization purposes where the underlying aluminum alloy covers a step, such as at an open via.
Claims10
A method for improving step coverage of a metallization layer on an integrated circuit having micron/submicron geometry contact vias, comprising the following sequential steps:
- depositing a metallization layer of an electrically conductive metal having a low melting and boiling point;
- depositing an anti-reflective coating on the metallization layer, the anti-reflective coating having a reflectivity value less than that of the metallization layer, the anti-reflective coating further having a melting and boiling point sufficiently higher than that of the metallization layer to insure that intermixing of the two layers and resultant increasing of resistivity of the metallization layer will not occur during laser planarization;
- and
- subjecting the resulting laminate to laser planarization to melt the metallization layer and cause it to flow into the contact vias without melting the anti-reflective coating.
1 more element
Dependencies are inferred from the claim text.