Patent ID: 7427338

Claim:
An electrochemical plating cell, comprising: a cell body configured to contain a plating solution and having an open upper portion configured to receive a substrate for plating; an anode positioned in the cell body; and a substantially rigid diffusion member positioned across the cell body between the anode and the open upper portion, wherein the diffusion member has a substantially uniform thickness and is made form a porous material, wherein the porous material has pores having a diameter of between about 0.1 microns and about 500 microns, and wherein the diffusion member comprises a plurality of spherically shaped ceramic particles that occupy between about 40% and 80% of a volume of the diffusion member, and wherein the pores are formed with a gradient across a width of the diffusion member, the gradient of pores being configured to compensate for non-uniformities in fluid flow through the diffusion member.