| CPC H01L 21/6833 (2013.01) [H01J 37/3244 (2013.01); H01J 37/32715 (2013.01)] | 20 Claims |

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1. A porous plug for use in a substrate support, comprising:
a porous central passageway; and
a solid outer shell bonded to and surrounding the porous central passageway such that there is no continuous gap between the porous central passageway and the solid outer shell along an entire length of the porous plug, wherein the solid outer shell includes a sealing surface disposed on a top end of the solid outer shell proximate a first end of the porous central passageway, and on an opposing bottom end of the solid outer shell proximate an opposing second end of the porous central passageway, to facilitate forming a seal along the sealing surface and surrounding the porous central passageway.
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