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Electroforming Stress and Pit-Free Molds From a Boric Acid Additive-Free Sulfamate Nickel Bath

IP.com Disclosure Number: IPCOM000036253D
Original Publication Date: 1989-Sep-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

DiCenzo, R: AUTHOR [+3]

Abstract

Disclosed is a process for electroforming stress and pit-free molds from a low boric acid, additive-free sulfamate nickel bath. In manufacturing an optical media disk, the electroformed nickel stamper plays a key role. The stamper is used in both the injection molding process and the photopolymerization process. The stamper carries the recording information that is transferred to the optical media disk. Therefore, the nickel stamper must be pit- and stress-free to avoid degradation of the recorded information.

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Electroforming Stress and Pit-Free Molds From a Boric Acid Additive-Free Sulfamate Nickel Bath

Disclosed is a process for electroforming stress and pit-free molds from a low boric acid, additive-free sulfamate nickel bath. In manufacturing an optical media disk, the electroformed nickel stamper plays a key role. The stamper is used in both the injection molding process and the photopolymerization process. The stamper carries the recording information that is transferred to the optical media disk. Therefore, the nickel stamper must be pit- and stress-free to avoid degradation of the recorded information.

To produce such a stamper, the current process uses a nickel sulfamate bath saturated with boric acid and including varying amounts of other additives, such as wetting agents and stress relievers. This new process utilizes a unique current density cycle to relieve internal stress and which gives as a side benefit a pit-free deposit. Other advantages of this process include: easier bath analysis and control, reduced boric acid usage, elimination of the need for frequent carbon filtration to control addition agent decomposition byproducts and that boric acid does not crystallize at room temperature as it does with the normally super-saturated bath.

The most significant of these advantages is the lack of boric acid crystallization at room temperature. Because of this, the normally heated bath may be allowed to cool to room temperature and need not be disposed of in the event of a power outage or equipment malfunct...