JP-2022518858-A5 -

Dates

Publication Date

20221202

Application Date

20200116

Description

This invention relates to the field of semiconductor manufacturing, and more specifically, to a semiconductor crystal growth apparatus. The CZ pulling method is an important technique for producing silicon single crystals for semiconductor wafers and solar energy. It involves heating and melting high-purity polysilicon raw material in a crucible using a carbon heater, then immersing a seed crystal in the melt. A series of steps (neck, sulphur, bodhi, tail, and cooling) are then performed to ultimately obtain a single-crystal ingot. In the crystal pulling process, reflector devices such as inlet tubes (or reflectors ) are often installed around the silicon crystal ingot. This is to block thermal radiation from the quartz crucible or the silicon melt within the crucible to the crystal surface during crystal growth, thereby increasing the axial temperature gradient of the crystal ingot and making the radial temperature distribution as uniform as possible. This controls the growth rate of the crystal ingot within an appropriate range while simultaneously suppressing internal defects in the crystal. Furthermore, by guiding the inert gas introduced from the top of the crystal growth furnace and allowing it to pass over the silicon melt surface at a higher flow rate, it is possible to control the oxygen and impurity content in the silicon crystal ingot. In the design process of semiconductor crystal growth equipment, it is necessary to consider the distance between the reflector device, the silicon molten surface, and the crystal ingot in order to control the axial temperature gradient and radial temperature distribution of the crystal ingot. Specifically, in the design process of the reflector device, two important parameters are often considered: the minimum distance between the reflector device and the liquid surface (hereinafter referred to as the liquid surface distance Drm) and the minimum distance between the reflector device and the crystal ingot (hereinafter referred to as the crystal ingot distance Drc). Here, Drm controls the stable growth of the silicon crystal between the crystal pulling liquid surface and the silicon crystal ingot, and Drc controls the axial temperature gradient of the silicon crystal ingot. In order to stably grow silicon crystals between the silicon crystal ingot and the silicon molten surface, the rising rate of the crucible is often controlled so that Drm remains stable within an appropriate range. For example, Japanese Patent Application No. 2000-160405 discloses a semiconductor crystal growth method and apparatus that suppresses defects occurring inside single-crystal silicon by providing a reflector device around single-crystal silicon and controlling the distance from the lower surface of the reflector device to the surface of the silicon melt and the pulling speed when extracting the single-crystal silicon. However, once the shape of the reflector device is fixed, the shape and position of the flow guide tube are also fixed, and if the shape of the silicon crystal ingot is constant, it is difficult to adjust the axial temperature gradient of the silicon crystal ingot by controlling the device itself to further reduce Drc . Therefore, to solve the problems of conventional technology, we propose a new semiconductor crystal growth apparatus. The "Summary of the Invention" section presents a simplified set of concepts, which are described in more detail in the "Specific Embodiments" section. The "Summary of the Invention" section of this invention is not intended to limit the main or essential technical features of the claimed technical solution, nor to determine the scope of protection for the claimed technical solution. The present invention provides a semiconductor crystal growth apparatus, and the apparatus is The furnace body and A crucible is provided inside the furnace body to hold the molten silicon, The furnace body is provided with a device for pulling up silicon crystal ingots from the silicon molten liquid and a reflector device, The reflector device comprises an inlet cylinder, which is cylindrical and positioned around the silicon crystal ingot, for rectifying the argon gas introduced from the top of the furnace body and adjusting the heat distribution between the silicon crystal ingot and the silicon molten surface . The reflector device further comprises an adjustment device positioned inside the lower end of the inlet cylinder for adjusting the minimum distance between the reflector device and the silicon crystal ingot. For example, the adjustment device includes an annular device provided to surround the inside of the inlet pipe. Exemplary, the annular device is constructed by joining at least two arc-shaped members. For example, the adjustment device is detachably connected to the inlet pipe . Exemplary, the inlet pipe comprises an inner cylinder, an outer cylinder, and an insulating material, wherein the bottom of the outer cylinder extends below the bottom o