Bottom edge ring and middle edge ring

A bottom ring is configured to support a movable edge ring. The edge ring is configured to be raised and lowered relative to the substrate support. The bottom ring includes: an upper surface, the upper surface being step-shaped; an annular inner diameter; an annular outer diameter; a lower surface; and a plurality of vertical guide channels provided through the bottom ring from the lower ring surface to the upper surface of the bottom ring. Each of the guide channels includes a first region having a smaller diameter than the guide channel, and the guide channels are configured to receive respective lift pins for raising and lowering the edge ring. 一种底部环被配置为支撑可移动的边缘环。所述边缘环被配置为相对于衬底支撑件升高和降低。所述底部环包括：上表面，所述上表面是台阶状的；环形内径；环形外径；下表面；和多个竖直引导通道，其穿过底部环从所述底部环的所述下环表面到所述上表面提供。所述引导通道中的每一个包括直径小于所述引导通道的第一区域，并且所述引导通道被配置接收用于使所述边缘环升高和降低的相应的升降销。