Anode
The electrode at which oxidation or corrosion of some component occurs (opposite of cathode). Electrons flow away from the anode in the external circuit. In the elctroplating process, anodes may also provide the raw material which keeps the electrolyte in balance by corroding charged metal ions into the solution. This is called an "active anode". (see passive anode) If the anode is used in this manner, the material of the anode must be the same as the plating material. For example, in the Nickel Sulfamate plating process, the anodes are composed of pure nickel. Some sulfer may also be incorporated in the anodes to promote good corrossion and chemical balance.

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March 8, 2004

Description: A raised bump on the backside of the stamper generally caused by some type of contaminant on the master during the StamperForming process. During backsanding, the nodule can break off leaving a void, pit, or ring.

Effect: Nodule will push through the stanper during molding resulting in a defect in the replica.

Acceptance Criteria: No more than 3 nodules of size < 200 um; no clusters.

Causes: Filters blown or bypassed Fliters clogged - low flow Filter mesh torn Contact Ring not clean Contamination in cells; e.g. hair from operator not wearing bouffant cap, dirt from street clothes, tools dropped into tank, airborne particles from improper air handling etc... DI water system defective allowing contamination into the bath Anodes and mesh not cleaned on a regular maintenance schedule Dust or other particles on master, fingerprints, glove prints, etc... Chemistry - Ni, Boric, Wetter out of recommended range Over saturation of boric acid; boric can crystalize in solution and on anode and cathode causing nodules to form

Nodules on Backsanded Stamper Nodule 99x Magnification