Claims
- 1. A process for the evaporation deposition of a layer of metal on a workpiece comprising the steps of:
- depositing a charge of a solid metal, having a selected vapor pressure at a selected temperature, in a crucible formed of a material having a vapor pressure lower than the vapor pressure of the metal at said selected temperature,
- placing a shield between the workpiece and the crucible,
- applying sufficient energy to the crucible to increase the temperature of the charge to a first level sufficient to melt said charge contained therein, but insufficient to cause substantial evaporation of said charge,
- increasing the energy applied to the crucible to increase the temperature of the charge to a second level, maintaining said temperature at said second level for a time sufficient to fractionally distill the charge and sublime or vaporize any non-metallic contaminants in said charge,
- altering the level of energy applied to the charge to set the temperature of the charge at a third level to evaporate the charge at a selected rate, and
- removing the shield from between the crucible and the workpiece to permit evaporant from the charge to coat the workpiece.
- 2. The process of claim 1 wherein said metal is copper.
- 3. The process of claim 1 wherein said metal is gold.
- 4. The process of claim 1 wherein said first level is approximately 1200.degree. C.,
- said second level is approximately 1900.degree. C., and
- said third level is approximately 1500.degree. C.
- 5. The process of claim 1 wherein there is provided the further step of replacing said shield between the workpiece and crucible after a selected period of time,
- altering the energy to set the temperature of the charge at a fourth level for a selected period of time,
- replenishing said charge, and
- reducing the energy to reset the temperature of the charge at said first level.
- 6. A process for the self-fractionation deposition of a metallic layer on a workpiece consisting of the steps of:
- depositing a body of copper in a molybdenum crucible which body is less than five-eights of the volume of the crucible,
- shielding the workpiece from the crucible with a removable shield,
- applying RF power to the crucible to heat the body of copper contained therein to a stable temperature of about 1200.degree. C.,
- increasing the RF power applied to the crucible and the body of copper, to increase the temperature of the charge about 1900.degree. C.,
- lowering the power level applied to the device to lower the temperature of the body of copper to 1510.degree. C., and
- removing the shield from between the crucible and the workpiece to permit evaporant from the body of copper to coat the workpiece.
Parent Case Info
This is a divisional application of Application No. 100,068, filed Sept. 23, 1987, now U.S. Pat. No. 4,791,261.
US Referenced Citations (10)
Divisions (1)
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Number |
Date |
Country |
Parent |
100068 |
Sep 1987 |
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