FIGS. 15A and 15B are views illustrating temperature reproducibility of the second heat treatment by the heat treatment apparatus having the first partitions 70 and 72. FIG. 15A is a graph which illustrates a change over time in the measured temperature in the area CB in the space S, and time is illustrated on the horizontal axis, and temperature [□] is illustrated on the vertical axis. FIG. 15B is a graph which illustrates a change over each run in the measured temperature at time tm2 in FIG. 15A, and the number of runs is illustrated on the horizontal axis, and temperature [□] at time tm2 is illustrated on the vertical axis. Further, a plurality of solid lines in FIG. 15A illustrate the result for each run.

As illustrated in FIGS. 15A and 15B, when the second heat treatment is performed using the heat treatment apparatus having the first partitions 70 and 72, it can be seen that, in all steps, the temperature fluctuation at each run becomes smaller than the case where the heat treatment apparatus of the related art is used.