Apparatus for depositing a thin film of material on a substrate and regeneration process for such an apparatus

A process for regenerating cryogenic panels of an apparatus for depositing a thin film of material on a substrate, said apparatus comprising:

• a vacuum chamber;
• a sample holder disposed inside said vacuum chamber, the sample holder being configured to support the substrate;
• a gas injector configured to inject a gaseous precursor into the vacuum chamber, a part of the gaseous precursor being configured to react at the surface of the substrate;
• at least a first cryogenic panel positioned inside the vacuum chamber, and configured to adsorb a part of the gaseous precursor which has not reacted at the surface of the substrate and to release the adsorbed gaseous precursor;
• a first trap connected to the vacuum chamber and configured to trap a part of the gaseous precursor released by the first cryogenic panel, the first trap having a fixed pumping capacity S1, and a second trap configured to trap an other part of the gaseous precursor released by the first cryogenic panel, the second trap having a variable pumping capacity S2 and configured to be regulated in function of the gaseous precursor partial pressure;
• the first trap and the second trap providing a total pumping capacity S=S1+S2 sufficient to maintain the gaseous precursor partial pressure in the vacuum chamber under a determined pressure PL;
• the process comprising:
• a) evacuation of the gaseous precursor out of the vacuum chamber, said evacuation comprising:
• heating the at least first cryogenic panel, producing a desorption of the gaseous precursor initially adsorbed on said first cryogenic panel, and
• trapping a part of said desorbed gaseous precursor by the first trap, a portion of said part of the desorbed gaseous precursor being trapped on a second cryogenic panel of said first trap, and
• b) regeneration of the second cryogenic panel of said first trap, said regeneration comprising:
• isolating said first trap from the vacuum chamber,
• heating said second cryogenic panel, producing a desorption of the trapped gaseous precursor from the second cryogenic panel, and
• pumping said desorbed gaseous precursor by one or more pumps to produce a vacuum,
• the process further comprising, during the trapping of the part of said desorbed gaseous precursor by the first trap in step a),
• conducting a complementary trapping operation, by the second trap, of an other part of said gaseous precursor released by said first cryogenic panel,
• said second trap having a variable pumping capacity S2 configured to be regulated in function of the gaseous precursor partial pressure,
• said trapping operations by the first and second traps providing a total pumping capacity S=S1+S2 sufficient to maintain the gaseous precursor partial pressure in the vacuum chamber under a determined pressure PL.