Lam Research Corporation

Bryan A Helmer

S M Reza Sadjadi

Douglas L Keil

James V Tietz

Helen H Zhu

Si Yi Li

Eric D Wagganer

A semiconductor manufacturing process wherein a low-k dielectric layer is plasma etched with selectivity to an overlying mask layer. The etchant gas can be oxygen-free and include a fluorocarbon reactant, a nitrogen reactant and an optional carrier gas, the fluorocarbon reactant and nitrogen reactant being supplied to a chamber of a plasma etch reactor at flow rates such that the fluorocarbon reactant flow rate is less than the nitrogen reactant flow rate. The etch rate of the low-k dielectric layer can be at least 5 times higher than that of a silicon dioxide, silicon nitride, silicon oxynitride or silicon carbide mask layer. The process is useful for etching 0.25 micron and smaller contact or via openings in forming structures such as damascene structures.

Method of plasma etching low-k dielectric materials

Methods for etching a trench into a dielectric layer are provided. One exemplary method controls an ion-to-neutral flux ratio during etching so as to achieve a neutral limited regime in an ion assisted etch mechanism where the neutral limited regime causes bottom rounding. The method includes modulating physical sputtering causing microtrenching to offset the bottom rounding so as to produce a substantially flat bottom trench profile. Some notable advantages of the discussed methods of etching a trench into a dielectric layer includes the ability to eliminate the intermediate etch stop layer. Elimination of the etch stop layer will decrease fabrication cost and process time. Additionally, the elimination of the intermediate stop layer will improve device performance.

Profile control of oxide trench features for dual damascene applications

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Fremont, CA, United States of America

Bryan A Helmer