GAS REACTION TRAJECTORY CONTROL THROUGH TUNABLE PLASMA DISSOCIATION FOR WAFER BY-PRODUCT DISTRIBUTION AND ETCH FEATURE PROFILE UNIFORMITY
First Claim
1. A method for delivering gases to a plasma processing chamber having a substrate support for supporting a substrate, a dielectric window disposed over the substrate support, a center region of the dielectric window includes a gas feed injector that has an inner feed and an outer feed that surrounds the inner feed, and an electrode is disposed over the dielectric window, the method comprising:
- convectively flowing a reactant gas into the plasma processing chamber via the inner feed of the gas feed injector;
diffusively flowing a tuning gas into the plasma processing chamber via the outer feed of the gas feed injector, the tuning gas having a different chemical composition than the reactant gas, the tuning gas is fed via the outer feed and into the plasma processing chamber at an angle that is away from the reactant gas that is fed via the inner feed and into the plasma processing chamber;
providing radio frequency (RF) power to the electrode, wherein a fraction of the tuning gas that is diffusively flown into the plasma processing chamber is exposed to the RF power and disassociated before mixing with the reactant gas that is convectively flown into the plasma processing chamber, wherein the RF power is configured to ignite a plasma using a mixture of the tuning gas, the fraction of tuning gas that is disassociated, and the reactant gas; and
adjusting a rate of flow of one or both of the convectively flown reactant gas and the diffusively flown tuning gas to control etch uniformity across a surface of the substrate.
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Abstract
Methods, systems, and computer programs are presented for controlling gas flow in a semiconductor manufacturing chamber. The method includes flowing a reactant gas thorough an inner feed and a tuning gas through an outer feed surrounding the inner feed, such that the gases do not mix until both are introduced in the chamber. Further, the flow of the reactant gas is convective, and the flow of the tuning gas is directed at an angle from the direction of the reactant gas, providing a delivery of the tuning gas in closer proximity to the RF power before further mixing with the reactant gas. Radio frequency power is provided to the electrode to ignite a plasma using the reactant and tuning gases. The diffusive flow of the tuning gas enables the tuning gas to be dissociated by the RF power allowing for control of the local residence time variation and preferential spatial dissociation patterns with respect to the local residence time of the reactant gas. The introduction of the gases into the chamber without pre-mixing imparts control of etch uniformity across the surface of the substrate during etching.
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Citations
20 Claims
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1. A method for delivering gases to a plasma processing chamber having a substrate support for supporting a substrate, a dielectric window disposed over the substrate support, a center region of the dielectric window includes a gas feed injector that has an inner feed and an outer feed that surrounds the inner feed, and an electrode is disposed over the dielectric window, the method comprising:
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convectively flowing a reactant gas into the plasma processing chamber via the inner feed of the gas feed injector; diffusively flowing a tuning gas into the plasma processing chamber via the outer feed of the gas feed injector, the tuning gas having a different chemical composition than the reactant gas, the tuning gas is fed via the outer feed and into the plasma processing chamber at an angle that is away from the reactant gas that is fed via the inner feed and into the plasma processing chamber; providing radio frequency (RF) power to the electrode, wherein a fraction of the tuning gas that is diffusively flown into the plasma processing chamber is exposed to the RF power and disassociated before mixing with the reactant gas that is convectively flown into the plasma processing chamber, wherein the RF power is configured to ignite a plasma using a mixture of the tuning gas, the fraction of tuning gas that is disassociated, and the reactant gas; and adjusting a rate of flow of one or both of the convectively flown reactant gas and the diffusively flown tuning gas to control etch uniformity across a surface of the substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for processing a substrate in a chamber, the method comprising:
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flowing separately a reactant gas through an inner feed of a gas feed injector into the chamber, the inner feed being defined at a center of a dielectric window of the chamber; flowing separately a tuning gas through an outer feed of the gas feed injector into the chamber, the outer feed surrounding the inner feed at the center of the dielectric window; providing radio frequency (RF) power to an electrode disposed over the dielectric window to ignite a plasma over the substrate; wherein the tuning gas is introduced at an angle that is away from the reactant gas, the reactant gas having a first flow rate that is higher than a second flow rate of the tuning gas, such that a fraction of the tuning gas is configured to dissociate by the RF power before being mixed with the reactant gas, such that a mixture of the reactant gas, the dissociated fraction of the tuning gas and the reactant gas produces a plasma over the substrate; and adjusting a rate of flowing of the reactant gas and tuning gas into the chamber to control a spatial plasma dissociation profile of the plasma for controlling etch uniformity over a surface of the substrate. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification