BACKGROUND

Field

Embodiments of the present disclosure generally relate to processing chambers and to backside gas delivery assemblies for use therein.

Description of the Related Art

In the manufacture of integrated circuits and other electronic devices, plasma processes are often used for deposition or etching of various material layers. High frequency power, such as a radio frequency (RF) power, is often used to generate the plasma, for example inside a process chamber. When RF power is applied to the substrate support, a direct current (DC) bias is also often applied to the substrate support to chuck the substrate to the substrate support during processing. To improve the thermal uniformity and heat transfer between the substrate support and the substrate during processing an inert gas, such as helium, is delivered to the backside of the substrate by a backside gas delivery assembly.

However, during processing the inert gas flowing through the backside gas delivery assembly may ionize at various points along the backside gas delivery assembly due to the proximity of the backside gas delivery assembly to RF power applied to the substrate support. The ionized inert gas may form parasitic plasma that propagates throughout the backside delivery gas assembly and deposits contaminants, such as metals, on the backside surface of the substrate that are not desired.

Therefore, there is a need for an improved backside gas delivery assembly that prevents inert gas from forming parasitic plasma.

SUMMARY

In one embodiment, a backside gas delivery assembly is provided. The backside gas delivery assembly includes a first gas channel disposed in a stem of a substrate support assembly. The substrate support assembly includes a substrate support having a second gas channel extending from the first gas channel. The backside gas delivery assembly further includes a porous plug disposed within the first gas channel positioned at an interface of the stem and the substrate support.

In another embodiment, a backside gas delivery assembly is provided. The backside gas delivery assembly includes a first gas channel disposed in a stem of a substrate support assembly. The substrate support assembly includes a substrate support having a second gas channel extending from the first gas channel. The backside gas delivery assembly further includes a porous plug disposed within the first gas channel positioned at an interface of the stem and the substrate support, a gas source connected to the first gas channel configured to deliver an inert gas to a backside surface of a substrate disposed on an upper surface of the substrate support, and a gas tube in the first gas channel extending to the porous plug positioned at the interface of the stem and the substrate support.

In yet another embodiment, a backside gas delivery assembly is provided. The backside gas delivery assembly includes a first gas channel disposed in a stem of a substrate support assembly. The substrate support assembly includes a substrate support having a second gas channel extending from the first gas channel. The backside gas delivery assembly further includes a porous plug disposed within the first gas channel positioned at an interface of the stem and the substrate support, a gas source connected to the first gas channel configured to deliver an inert gas to a backside surface of a substrate disposed on an upper surface of the substrate support, and a gas tube connected to an electrical ground having an inner diameter between about 0.025 inches and 0.075 inches and an inner surface having a surface finish less than 5 microinches, the gas tube bonded to the first gas channel and extending to the porous plug positioned at the interface of the stem and the substrate support.

