Ablation patterning of multi-layered structures
AssigneesSiemens Aktiengesellschaft, International Business Machines Corporation
InventorsAlexander Mitwalsky, James Gardner Ryan, Thomas Anthony Wassick
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Abstract
A process for ablation etching through one or more layers of dielectric materials while not etching an underlying conductive material layer comprises selecting parameters whereby the ablation process automatically stops when the conductive material layer is reached, or monitoring the process for end point detection of the desired degree of ablation. Parameters selected are the absorptivity of the dielectric layer versus that of the conductive material layer. End point detection includes monitoring radiant energy reflected from the workpiece or the content of the materials being ablated from the workpiece.
Claims14
A process for patterning a multi-layered workpiece comprising the steps of
- providing a first layer of a dielectric material on a surface of an electrically conductive body,
- providing a second layer of a polymeric material overlying said first layer, and
- ablation etching a pattern of openings through both said first and second layers for exposing surface portions of said conductive body through said openings, and wherein said ablation etching step comprises
- directing radiant energy against said workpiece,
- detecting and monitoring reflected radiation from said workpiece, and
- stopping said ablation etching upon ascertaining a change from a first reflected radiation to a second reflected radiation, said first reflected variation representing reflected radiation that varies as a function of time at a higher rate than said second reflected radiation, thereby allowing said ablation etching to be stopped upon reaching said conductive body independent of process conditions.
A process for patterning a multi-layered workpiece comprising the steps of
- providing a overlying layer on a surface of an electrically conductive body, said overlying layer being one of a dielectric layer and a polymeric layer different from said dielectric layer;
- ablation etching a pattern of openings through said overlying layer for exposing surface portions of said conductive body through said openings, and wherein said ablation etching step comprises
- directing radiant energy against said workpiece,
- detecting and monitoring reflected radiation from said workpiece, and
- stopping said ablation etching upon ascertaining a change from a first reflected radiation to a second reflected radiation, said first reflected variation representing reflected radiation that varies as a function of time at a higher rate than said second reflected radiation, thereby allowing said ablation etching to be stopped upon reaching said conductive body independent of specific materials comprising said overlying layer and said conductive body.
A process for patterning a multi-layered workpiece comprising the steps of
- providing a first layer of a dielectric material on a surface of an electrically conductive body,
- providing a second layer of a polymeric material overlying said first layer, and
- ablation etching a pattern of openings through both said first and second layers for exposing surface portions of said conductive body through said openings, and wherein said ablation etching step comprises
- directing first radiant energy having a first radiant energy level against said second layer on said workpiece,
- monitoring reflected radiation from said workpiece to ascertain when said ablation etching reaches said first layer,
- directing second radiant energy having a second radiant energy level higher than said first radiant energy level against said first layer through openings in said first layer,
- stopping said directing said second radiant energy upon ascertaining a change from a first reflected radiation to a second reflected radiation, said first reflected variation representing reflected radiation that varies as a function of time at a higher rate than said second reflected radiation, thereby allowing said ablation etching to be stopped upon reaching said conductive body independent of process conditions.
Dependencies are inferred from the claim text.