Crystal diameter control method for Czochralski silicon single crystal growth process

Abstract

The invention relates to a semiconductor crystal manufacturing technology and aims to provide a crystal diameter control method for a Czochralski silicon single crystal growth process. The method comprises the following steps: when a silicon single crystal is produced by a Czochralski method, enabling the crystal to reach a stable state in the equal-diameter growth process; setting the actual pulling speed of the crystal as the current average pulling speed, and making the actual pulling speed close to the set pulling speed according to a preset change rate until the pulling speed of the crystal is constant and does not fluctuate with the diameter of the crystal; in the equal-diameter growth process of the crystal, controlling the diameter of the crystal by adjusting the power of a heater,and particularly adding variable period pulse type power output on the basis of the current heating average power. According to the method, through calculation of crystal diameter change speed and acceleration and critical value control, the key point judgment of power output time is more reasonable and accurate; the response time lag of the diameter change to power regulation can be shortened; the crystal diameter cannot be greatly disturbed, and the crystal diameter cannot easily fluctuate greatly.

Description

technical field [0001] The patent of the invention is applicable to semiconductor crystal manufacturing technology, and specifically relates to a crystal diameter control method used in the Czochralski silicon single crystal growth process. [0002] technical background [0003] In the traditional Czochralski silicon single crystal growth process, the crystal diameter is generally controlled by adjusting the crystal pulling speed. Because the crystal diameter change responds quickly to the adjustment of the pulling speed, a better diameter control effect can be obtained. In order to control and reduce micro-defects in high-end semiconductor-grade silicon single crystals, the consensus in the industry is to achieve this through V / G regulation at the crystal growth interface. Among them, G refers to the temperature gradient at the crystal growth interface, which is mainly determined by the relative position of the growth interface in the thermal field. Because the position of...

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Problems solved by technology

In the process of controlling the crystal diameter by changing the pulling speed in the traditional process, there is a problem of large fluctuations in the pulling speed, which easily makes the crystal growth conditions exceed the compound V / G range, resulting in a decrease in crystal quality and low yield

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