Light irradiation type heat treatment method and heat treatment apparatus
A semiconductor wafer is preheated with a halogen lamp, and then is heated by irradiation with a flash of light emitted from a flash lamp. The preheating with the halogen lamp is continued for a short time even after the flash lamp turns off. A radiation thermometer measures a front surface temperature and a back surface temperature of the semiconductor wafer. A temperature integrated value is calculated by integration of temperatures of the semiconductor wafer measured during a period from a start of the flash irradiation to an end of the heating of the semiconductor wafer. It is determined that the semiconductor wafer is cracked at the time of flash irradiation when the calculated temperature integrated value deviates from a preset range between an upper limit value and a lower limit value.
1 . A heat treatment apparatus for heating a substrate by irradiating the substrate with a flash of light, comprising:
a chamber for receiving a substrate therein;
a susceptor for holding the substrate in said chamber;
a continuous lighting lamp for irradiating said substrate held by said susceptor with light to heat said substrate to a preheating temperature;
a flash lamp for irradiating a front surface of said substrate with a flash of light to a susceptor for holding the substrate in said chamber;
a radiation thermometer for measuring a temperature of said substrate;
a calculation part for integrating temperatures of said substrate measured by said radiation thermometer during a period from a start of said flash irradiation to an end of the heating of said substrate to calculate a temperature integrated value; and
a determination part for determining that said substrate is cracked when said temperature integrated value deviates from a preset range between an upper limit value and a lower limit value, wherein
said radiation thermometer includes a front surface radiation thermometer for measuring a front surface temperature of said substrate, and a back surface radiation thermometer for measuring a back surface temperature of said substrate;
said calculation part integrates front surface temperatures of said substrate and back surface temperatures of said substrate; and
said determination part determines that said substrate is cracked when a front surface temperature integrated value obtained by integrating the front surface temperatures of said substrate deviates from a preset range between an upper limit value
and a lower limit value and a back surface temperature integrated value obtained by integrating the back surface temperatures of said substrate deviates from a preset range between an upper limit value and a lower limit value.
2 . The heat treatment apparatus according to claim 1 , wherein
said calculation part integrates temperatures of said substrate measured during a period from the start of said flash irradiation to an end of the heating of said substrate with said flash lamp.
3 . The heat treatment apparatus according to claim 1 , wherein
when said determination part determines that said substrate is cracked, supply and exhaust of gas into and out of said chamber are stopped.