Manufacture of semiconductor device

Abstract

Abstract PURPOSE:To maintain the electric characteristics of a semiconductor element by a method wherein, in the case of laser irradiation where a shifting of flatband voltage is generated in the laser process, a low power laser beam is reirradiated, thereby enabling to recover the flatband voltage to the level maintained before shifting. CONSTITUTION:When a powerful laser beam is irradiated on a silicon substrate 1 whereon an oxide film 2 is attached, silicon is fused and the stress of the oxide film 2 is released, and an unevenness phenomenon is generated. When a laser beam having the power of 7-8W is irradiated on the uneven part, the flatband voltage is restored. Accordingly, when the laser, having the power with which a change is made in flatband voltage due to having the laser process such as activation and the like of the ion layer of the substrate, is irradiated, a laser beam of low power of 7-8W is reirradiated after the irradiation of laser. Said low power laser irradiation can be performed easily by lowering the power of the source of laser beam. Also, the period of irradiation of such a low power laser irradiation is determined by measuring the time required for recovery of the flatband voltage in advance. Accordingly, the above-mentioned laser irradiation can be performed easily using the laser irradiation device used before.

Inventors

• 👤 Nobuo Sasaki
• 👤 伸夫 佐々木

Bibliographic Details