Process for forming a lead film

Claim 1

A process for forming a lead film including a closed type crucible having at least one injection nozzle, means for heating and vaporizing lead, an ionization chamber, an acceleration electrode having an acceleration voltage, a shutter, a substrate, temperature control means for controlling the temperature of said substrate, and a vacuum chamber surrounding said crucible, said heating and vaporizing means, said ionization chamber, said acceleration electrode, said shutter, said substrate, and said temperature control means, wherein said process comprises: heating and vaporizing said lead in said crucible to form a pressurized lead vapor; injecting said lead vapor through said at least one injection nozzle into said vacuum chamber; maintaining a pressure differential between said vacuum chamber and said lead vapor in said crucible at a ratio of less than or equal to 10 -2 ; using said pressure differential to form a vapor stream of said lead; generating electron beams within said ionization chamber; directing said electron beams through said vapor stream so as to form an ionized portion of said vapor stream; accelerating said ionized portion of said vapor stream toward said substrate with said acceleration electrode; impinging said vapor stream upon said substrate such that said lead film is deposited thereon; using said shutter for selectively shielding said substrate from the flow of said vapor stream; controlling the packing density of said lead film by regulating said acceleration voltage; and controlling the surface flatness of said lead film by regulating said temperature control means such that the temperature of said substrate is maintained below the melting point of lead.