| 摘要 |
An object of the present invention is to provide a production method which is low in cost and easily and surely increases surface layer cleanliness (purity) of a quartz glass jig used in semiconductor industry, and to provide a quartz glass jig improved in surface layer cleanliness (purity). <??>The above object is solved in a first embodiment of the invention comprising processing a quartz glass material through various treatments including flame treatment into a desired shape, then annealing it for strain removal, and washing it, whereby the shaped tool is heated at a high temperature falling between 800 DEG C and 1300 DEG C for at least 30 minutes in a clean atmosphere containing HCI gas, the heating step being after it is annealed for strain removal but before being washed. In a second alternative the step of annealing the shaped tool for strain removal is effected in a clean atmosphere containing HCL gas at a temperature falling between 800 DEG C and 1300 DEG C for at least 30 minutes (instead of the heat treatment step in HCL). <??>A quartz glass tool for use in the field of semiconductor industry is obtained showing a total mean concentration of Li, Na, Mg, K, Ca, Fe, Cr, Ni and Cu of at most 1.0 ppm in its surface layer to a depth of at least 100 mu m. |
