Electroplating system including an improved base structure

An electroplating system comprising:

• a container holding a plating solution;
• an anode immersed in the plating solution;
• a rotatable wafer holder assembly;
• and
• a base structure configured to support a wafer, the base structure comprising:
• an annular member;
• a contact ring attached to an inner surface of the annular member;
• and
• a pair of vertically extending shield structures attached to an upper surface of the annular member, each shield structure comprising:
• a curved plate having a plurality of discharging openings;
• a plurality of bevels formed in the curved plate, each bevel leading to a corresponding one of the plurality of discharging openings;
• and
• a plurality of baffles, each of the plurality of baffles corresponding to a respective one of the plurality of discharging openings and extending outward from the curved plate to prevent plating solution residual from reentering the base structure through the plurality of discharging openings.

An electroplating system comprising:

• an anode;
• and
• a cathode assembly comprising a wafer holder and a base structure, the base structure comprising:
• an annular member;
• a contact ring attached to the annular member;
• and
• a shield structure attached to an upper surface of the annular member, the shield structure comprising a curved plate having a plurality of discharging openings and a plurality of slopes formed therein;
• wherein each of the plurality of slopes corresponds to one of the plurality of discharging openings;
• wherein each of the plurality of slopes is cut into the curved plate at an angle of between 20 degrees and 50 degrees relative to a tangential surface of the curved plate to guide plating solution residual out of the base structure.