Gas reaction trajectory control through tunable plasma dissociation for wafer by-product distribution and etch feature profile uniformity

Patent metadata

Field	Value
Publication number	US-2016293431-A1
Application number	US-201514675659-A
Country	US
Kind code	A1
Filing date	Mar 31, 2015
Priority date	Mar 31, 2015
Publication date	Oct 6, 2016
Grant date	—

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.

First claim

What is claimed is:

1 . A method for delivering gases to a plasma processing chamber, comprising:
the plasma processing chamber including walls, a substrate support, 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, an electrode is disposed over the dielectric window for providing power through the dielectric window and to a plasma region that is disposed between the dielectric window and the substrate support configured to support a substrate; flowing a reactant gas to the inner feed, the flowing of the reactant gas is set at a convective flow so that the reactant gas has a first flow rate and is directed perpendicular to the substrate; flowing a tuning gas to the outer feed, the flowing of the tuning gas to the outer feed is not mixed with the reactant gas until both the reactant gas and the tuning gas are introduced in the plasma region, the flowing of the tuning gas is set at a diffusive flow so that the tuning gas has a second flow rate that is less than the first flow rate, and is directed at an angle that is away from the reactant gas between perpendicular to the substrate and parallel to the dielectric window; and providing radio frequency (RF) power to the electrode so that a plasma is ignited in the plasma region over the substrate using the reactant gas and the tuning gas, the angle at which the tuning gas is introduced into the plasma region is such that at least a portion of the tuning gas that is closer to the dielectric window is exposed to the RF power provided through the dielectric window before mixing with the reactant gas; wherein the diffusive flow of the tuning gas enables the portion of the tuning gas to be dissociated by the RF power and a portion to not be dissociated before being mixed with the reactant gas and ignited to form the plasma in the plasma region; wherein introduction of the reactant gas and the tuning gas into the chamber without pre-mixing imparts control of etch uniformity across a surface of the substrate during active etching of a material of the substrate; wherein etch uniformity is controlled in part by setting either one or both of the reactant gas and tuning gas to include a passivation component.

2 . The method as recited in claim 1 , wherein the tuning gas is a gas used to manage etching performance on the surface of the substrate, the tuning gas used to control the dissociation pattern of reactants gases being injected into the chamber, wherein the tuning as is one of a passivation or a reactant moiety.

3 . The method as recited in claim 1 , further including:
flowing a side gas through a side feed at a side of the chamber, the side gas being another tuning gas.

4 . The method as recited in claim 1 , further including:
wherein the second flow rate is less than the first flow rate.

5 . The method as recited in claim 1 , further including:
tuning a ratio between a volume flow of the reactant gas and a volume flow of the tuning gas.

6 . The method as recited in claim 1 , wherein the diffusive gas flow from the tuning gas couples into deposition zones directly underneath the dielectric window in close proximity to the outer feed.

7 . The method as recited in claim 1 , wherein the outer feed includes a plurality of holes defined on a circle concentric with the inner feed.

8 . The method as recited in claim 1 , wherein a dissociation rate in the chamber is controlled by adjusting the convective flow and the diffusive flow.

9 . The method as recited in claim 1 , wherein operations of the method are performed by a computer program when executed by one or more processors, the computer program being embedded in a non-transitory computer-readable storage medium.

10 . A method for delivering gases to a plasma processing chamber, comprising:
the plasma processing chamber including walls, a substrate support, 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, an electrode is disposed over the dielectric window for providing power through the dielectric window and to a plasma region that is disposed between the dielectric window and the substrate support configured to support a substrate; flowing a first gas type to the inner feed; flowing a second gas type to the outer feed, the second gas type being different than the first gas type, such that the first gas type and the second gas type are not mixed before being introduced into the plasma region; and providing radio frequency (RF) power to the electrode so that a plasma is ignited in the plasma region over the substrate using the first and second gas types, wherein mixing within the plasma region when the plasma is ignited defines a plasma dissociation pattern between the first and second gas types; wherein the second gas is introduced at an angle that is away from the first gas, and the first gas has a first flow rate that is higher than a second flow rate of the second gas, such that the second gas is configured to at least partially dissociate by the RF power being provided through the dielectric window and being in closer proximity to the second gas that is introduced at the angle, the at least partially dissociated second gas is then mixed with the first gas to ignite the plasma in the plasma region; wherein the first gas type includes a reactant component; wherein the second gas includes a tuning component; wherein the reactant component and the tuning component define the plasma dissociation pattern over the substrate, wherein introduction of the first gas type and the second gas type into the chamber without pre-mixing imparts control of etch uniformity across a surface of the substrate when the plasma is ignited to cause an etching of a material of the substrate; wherein etch uniformity is controlled in part by setting either one or both of the first and second gas types to include a passivation component.

11 . The method as recited in claim 10 , wherein the reactant component of the first gas type is a source of species for etching the substrate.

12 . The method as recited in claim 10 , wherein the first gas is selected from a group consisting of chlorine, or hydrogen bromide, or sulfur hexafluoride.

13 . The method as recited in claim 10 , wherein the second gas is selected from a group consisting of oxygen, or helium, or argon, or methane, or carbon dioxide.

14 . A method for processing a substrate in a chamber, the method comprising:
setting parameters for a gas box, the parameters defining a first gas flow and a second gas flow, the first gas flow including one or more first gases, and the second gas flow including one or more second gases, wherein the first gas flow includes one of reactant gases, or tuning gases, or a mixture of reactant and tuning gases, wherein the second gas flow includes one of reactant gases, or tuning gases, or a mixture of reactant and tuning gases, wherein the first gas flow and the second gas flow are independently set by a controller; flowing the first gas flow through an inner feed into the chamber, the inner feed being defined at a center of a dielectric window of the chamber; flowing the second gas flow through an outer feed into the chamber, the outer feed surrounding the inner feed at the center of the dielectric window, wherein the first gas flow and the second gas flow are not mixed before flowing into the chamber; and providing radio frequency (RF) power to an elec

Assignees

• Lam Res Corp

Inventors

• Sriraman Saravanapriyan
• Titus Monica
• Paterson Alex

Classifications

• H10P72/0421

  for drying etching · CPC title

• H10P14/60

  of insulating materials · CPC title

• H10P50/242 Primary

  of Group IV materials · CPC title

• C23C16/45574

  Nozzles for more than one gas · CPC title

• H01J37/32449

  Gas control, e.g. control of the gas flow · CPC title