Process for cleaning CVD units
AssigneeSiemens Aktiengesellschaft
InventorsElke Fritsch, Christine Dehm, Hermann Wendt, Volker Weinrich
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Abstract
A cleaning process for cleaning CVD units is disclosed. In the cleaning process, alkaline earth metal and/or metal-containing process residues, which form an amorphous film on reactor walls, are removed using a dry etching medium containing free diketones at a greatly reduced pressure and an elevated temperature. In the process, the free diketones react with the alkaline earth metals or metals to form volatile complexes.
Claims27
A process for cleaning chemical vapor deposition (CVD) units used for depositing oxide ceramics, the CVD units have surfaces facing a process space being coated with residues containing alkaline earth metals, which comprises:
- carrying out a cleaning process using an etching medium containing diketones including free diketones coming into contact with process residues, the free diketones reacting with process residues to form alkaline earth metal complexes;
- and
- forming the etching medium with at least one compound selected from the group consisting of ammonia, amines, polyether additives, polyamine additives and tetraglyme for preventing oligomerization of the alkaline earth metal complexes.
A process for cleaning chemical vapor deposition (CVD) units used for depositing oxide ceramics, the CVD units have surfaces facing a process space being coated with residues containing alkaline earth metals, which comprises:
- performing at least one-cleaning cycle, which includes;
- starting a cleaning process using an etching medium containing diketones including free diketones;
- including in the etching medium a ligand selected from the group consisting of ammonia, amines, polyether additives, polyamine additives, and tetraglyme for preventing oligomerization of the alkaline earth metal complexes;
- putting the etching medium into contact with process residues at an initial pressure and an initial temperature, the etching medium acting on the process residues for a specified time, during which the free diketones together with the process residues alkaline earth metal complexes, the alkaline earth metal complexes substantially remaining on surfaces of a CVD unit being cleaned at the initial temperature and the initial pressure;
- and
- removing subsequently the alkaline earth metal complexes from the surfaces at an elevated temperature and at a greatly reduced pressure compared with standard normal conditions.
Dependencies are inferred from the claim text.