Vacuum evaporation method

Claim 1

A METHOD OF FORMING HIGH PURITY COATINGS UPON A SUBSTRATE COMPRISING THE STEPS OF MOUNTING SAID SUBSTRATE WITHIN A VACUUM CHAMBER IN SPACED RELATIONSHIP TO AN EVAPORATION SOURCE STRUCTURE; PROVIDING A REMOVABLE SHIELD ADJACENT SAID SUBSTRATE TO SELECTIVELY SHIELD A SURFACE OF SAID SUBSTRATE FROM SAID SOURCE ; PLACING A COATING MATERIAL WITHIN SAID SOURCE; ATTAINING A VACUUM WITHIN SAID CHAMINCLUDING THE STEPS OF EMPLOYING A WATER ASPIRATOR TO REDUCE THE PRESSURE WITHIN SAID CHAMBER TO A FEW MM. HG, OPERATING A FIRST LIQUID HELIUM PUMP FOR A TIME SUFFICIENT TO FURTHER REDUCE THE PRESSURE WITHIN SAID CHAMBER TO ABOUT 10-5 MM. HG, SUBJECTING SAID CHAMBER TO A PREDETERMINATED TEMPERATURE TO REMOVE A PORTION OF SORBED GASES THEREFROM, COOLING SAID CHAMBER, ISOLATING SAID FIRST HELIUM PUMP FROM SAID CHAMBER, OPERATING AN ELECTRONIC ION PUMP TO STILL FURTHER REDUCE THE PRESSURE WITHIN SAID CHAMBER, OPERATING A SECOND LIQUID HELIUM PUMP LOCATED WITHING SAID CHAMBER TO REDUCE THE PRESSURE THEREIN TO ABOUT 10-10MM. HG., OUTGASSING SAIDSOURCE BY HEATING SAID SOURCE UNTIL ABOUT 10% OF THE MATERIAL CONTAINED THEREIN IS EVAPORATED; REMOVING SAID SHIELD FROM SAID SUBSTRATE SURFACE; AND SUBJECTING SAID SOURCE TO A PREDETERMINED TEMPERATURE AT WHICH SAID MATERIAL VAPORIZES AND DEPOSITS UPON SAID SUBSTRATE SURFACE WHILE SAID SECOND HELIUM PUMP MAINTAINS THE PRESSURE WITHIN SAID CHAMBER IN THE RANGE OF 1 TO 5X10-9MM. HG.

Claim 2

A METHOD OF FORMING HIGH PURITY COATINGS UPON A SUBSTRATE COMPRISING THE STEPS OF MOUNTING SAID SUBSTRATE WITHIN A VACUUM CHAMBER IN SPACED RELATIONSHIP TO AN EVAPORATION SOURCE STRUCTURE; PROVIDING A REMOVABLE SHIELD ADJACENT SAID SUBSTRATE TO SELECTIVELY SHIELD A SURFACE OF SAID SUBSTRATE FROM SAID SOURCE ; PLACING A COATING MATERIAL WITHIN SAID SOURCE; ATTAINING A VACUUM WITHIN SAID CHAMINCLUDING THE STEPS OF EMPLOYING A WATER ASPIRATOR TO REDUCE THE PRESSURE WITHIN SAID CHAMBER TO A FEW MM. HG, OPERATING A FIRST LIQUID HELIUM PUMP FOR A TIME SUFFICIENT TO FURTHER REDUCE THE PRESSURE WITHIN SAID CHAMBER TO ABOUT 10-5 MM. HG, SUBJECTING SAID CHAMBER TO A PREDETERMINATED TEMPERATURE TO REMOVE A PORTION OF SORBED GASES THEREFROM, COOLING SAID CHAMBER, ISOLATING SAID FIRST HELIUM PUMP FROM SAID CHAMBER, OPERATING AN ELECTRONIC ION PUMP TO STILL FURTHER REDUCE THE PRESSURE WITHIN SAID CHAMBER, OPERATING A SECOND LIQUID HELIUM PUMP LOCATED WITHING SAID CHAMBER TO REDUCE THE PRESSURE THEREIN TO ABOUT 10-10MM. HG., OUTGASSING SAIDSOURCE BY HEATING SAID SOURCE UNTIL ABOUT 10% OF THE MATERIAL CONTAINED THEREIN IS EVAPORATED; REMOVING SAID SHIELD FROM SAID SUBSTRATE SURFACE; AND SUBJECTING SAID SOURCE TO A PREDETERMINED TEMPERATURE AT WHICH SAID MATERIAL VAPORIZES AND DEPOSITS UPON SAID SUBSTRATE SURFACE WHILE SAID SECOND HELIUM PUMP MAINTAINS THE PRESSURE WITHIN SAID CHAMBER IN THE RANGE OF 1 TO 5X10-9MM. HG.