Silicon substrate and manufacturing method of the same

摘要

A condition of a single crystal manufacturing step subjected to the Czochralski method applying an initial oxygen concentration, a dopant concentration or resistivity, and a heat treatment condition is determined simply and clearly on the basis of the conditions of a wafer manufacturing step and a device step so as to obtain a silicon wafer having a desired gettering capability. A manufacturing method of a silicon substrate which is manufactured from a silicon single crystal grown by the CZ method and provided for manufacturing a solid-state imaging device is provided. The internal state of the silicon substrate, which depends on the initial oxygen concentration, the carbon concentration, the resistivity, and the pulling condition of the silicon substrate, is determined by comparing a white spot condition representing upper and lower limits of the density of white spots as device characteristics with the measured density of white spots.

主权项

1. A manufacturing method of a silicon substrate which is manufactured from a silicon single crystal grown by a CZ method and used for manufacturing a solid-state imaging device, the manufacturing method comprising the steps of:
setting a white spot condition representing upper and lower limits of the density of white spots as device characteristics; setting a gettering capability of the silicon substrate, a BMD density and a BMD size of the silicon substrate by applying a heat treatment condition of a device manufacturing step; calculating pulling process conditions which include an initial oxygen concentration, an initial carbon concentration, a resistivity, and a thermal history of the silicon single crystal under pulling from the conditions which are the gettering capability of the silicon substrate, the BMD density and the BMD size and the heat treatment condition of a device manufacturing step, thereby determining the pulling process conditions including the initial oxygen concentration, a carbon concentration, the resistivity, and a thermal history of the single-crystal silicon in the pulling process; manufacturing an evaluation device formed on a silicon substrate sliced from the silicon single crystal pulled under the determined pulling conditions, and measuring the density of white spots in the evaluation device, wherein when a leak current of higher than 10 μA flows through the evaluation device, white spots are evaluated, and the number of white spots are measured; comparing the measurement result with the white spot condition and re-setting an IG condition when this value does not satisfy the white spot condition; and when the value satisfies the white spot condition, determining on the basis of the pulling process conditions the internal state of the silicon substrate which depends on the initial oxygen concentration, the carbon concentration, the resistivity, and the thermal history of the silicon substrate to be provided to the solid-state imaging device to be manufactured; and manufacturing a silicon substrate by using the pulling process conditions determined.