Fabrication of moly masks by electroetching

An apparatus for electroetching molybdenum foil with a liquid electrolyte, the molybdenum foil having two surfaces, the apparatus comprising:

• a container for holding an electrolyte comprising a 2M-5M aqueous solution of sodium nitrate;
• a cathode disposed within the container and adapted to be immersed in the electrolyte;
• holding means for holding the molybdenum foil such that the molybdenum foil is disposed within the container and adapted to be immersed in the electrolyte;
• flow means for inducing electrolyte flow over the molybdenum foil;
• anode means for applying a relatively positive electrical voltage to the molybdenum foil;
• and
• cathode means for applying a relatively negative electrical voltage to the cathode.

A method of etching a metal foil, the foil having two sides together defining a mask area, the method comprising the steps of:

• placing a stationary photoresist mask pattern onto both sides of the mask area of the foil, the photoresist mask pattern including bare regions and coated regions;
• disposing a cathode on each side of said foil, each cathode at a fixed inter-electrode distance from the photoresist mask pattern;
• filling a space between the mask area and the cathode with a liquid electrolyte;
• inducing the electrolyte to flow over the mask area;
• providing a relatively positive voltage to the foil and a relatively negative voltage to the cathode, such that the foil is electroetched in the bare regions;
• and
• maintaining the relatively positive foil voltage and the relatively negative cathode voltage until the foil is etched through to provide openings.

An apparatus for electroetching a metal foil with a liquid electrolyte, the foil having two surfaces, each surface having a stationary photoresist mask, the apparatus comprising:

• a container for holding the electrolyte;
• two cathodes disposed within the container and adapted to be immersed in the electrolyte;
• holding means for holding the foil such that the foil is disposed between the two cathodes and adapted to be immersed in the electrolyte;
• flow means for inducing the electrolyte to flow over the foil;
• anode means for applying a relatively positive electrical voltage to the foil;
• and
• cathode means for applying a relatively negative electrical voltage to the cathode.

A method of etching a metal foil, the foil having a mask area, the method comprising the steps of:

• placing a masking pattern onto the mask area of the foil, the masking pattern including bare regions and coated regions;
• disposing a cathode at a fixed inter-electrode distance from the mask area;
• filling a space between the mask area and the cathode with a liquid electrolyte;
• inducing the electrolyte to flow over the mask area;
• assuring a substantially uniform electrolyte flow using an hydraulic resistance element;
• providing a relatively positive voltage to the foil and a relatively negative voltage to the cathode, such that the foil is electroetched in the bare regions;
• and
• maintaining the relatively positive foil voltage and the relatively negative cathode voltage until the foil is etched through to provide openings.

An apparatus for electroetching metal foil with a liquid electrolyte, the foil having two surfaces, the apparatus comprising:

• a container for holding an electrolyte;
• a cathode disposed within the container and adapted to be immersed in the electrolyte;
• holding means for holding the foil such that the foil is disposed within the container and adapted to be immersed in the electrolyte;
• flow means which includes all hydraulic resistance element providing a substantially uniform electrolyte flow over the mask area of the foil;
• anode means for applying a relatively positive electrical voltage to the foil;
• and
• cathode means for applying a relatively negative electrical voltage to the cathode.