Method for heating semiconductor wafer by means of application of radiated light

DETAILED DESCRIPTION With the foregoing in view, the present invention has as its object the provision of a heating method of a semiconductor wafer by means of application of radiated light without developing such large "warping" as impairing subsequent treatment and/or processing steps of the semiconductor wafer or such a damage as "slip line".
In one aspect of this invention, there is thus provided a method for heating a semiconductor wafer by means of application of light radiated from a light source while additionally heating a circumferential portion of the semiconductor wafer by subsidiary heating means which per se is heated upon exposure to the radiated light and is arranged in contact with the surface of a circumferential edge or a surface portion lying in the vicinity of the circumferential edge of the semiconductor wafer, which method comprises limiting the ratio (.
alpha.
/.
beta.
) of the characteristic value (.
alpha.
) of the subsidiary heating means to that (.
beta.
) of the semiconductor wafer to from 0.
7 to 1.
3, said .
alpha.
and .
beta.
being expressed respectively by the following formulae: ##EQU2## where .
eta.
.
sub.
1, .
eta.
.
sub.
2 : reflectivities of the subsidiary heating means and semiconductor wafer, respectively; .
rho.
.
sub.
1, .
rho.
.
sub.
2 : specific gravities (g/cm.
sup.
3) of the subsidiary heating means and semiconductor wafer, respectively; d.
sub.
1, d.
sub.
2 : thicknesses (cm) of the subsidiary heating means and semiconductor wafer, respectively; and C.
sub.
1, C.
sub.
2 : specific heats (joule/g.
.
degree.
C.
) of the subsidiary heating means and semiconductor wafer, respectively.
The heating method of this invention is effective in improving the uniformity of the temperature distribution on a wafer surface, thereby successfully preventing the occurrence of such large "warping" as to impair subsequent treatment and/or processing steps and such a damage as "slip line".
Therefore, the present invention is extremely valuable from the practical viewpoint.
The above and other objects, features and advantages of the present invention will become apparent from the following description and the appended claims, taken in conjunction with the accompanying drawings