CN-122013301-A - Air guide heat shield and method for enhancing uniformity of monocrystalline products and monocrystalline furnace

Abstract

The invention provides a gas-guide heat shield and method for enhancing uniformity of monocrystalline products and a monocrystalline furnace, and belongs to the technical field of semiconductor processing. The air guide heat shield for enhancing uniformity of monocrystalline products comprises an air guide heat shield which is provided with a hollow cavity which is penetrated in the axial direction and sleeved at the bottom of a guide cylinder and is penetrated in the axial direction with the guide cylinder, wherein the bottom of the air guide heat shield protrudes out of the bottom of the guide cylinder, and a through hole is formed in the side wall of the air guide heat shield. According to the invention, the air guide heat insulation cover is arranged on the guide cylinder, and the through holes are arranged on the side wall of the air guide heat insulation cover, so that effective heat insulation between ‌ heat shields and crystal bars and directional air flow guiding ‌ are realized, and the distribution of a thermal field and the discharge of impurities in the growth process of monocrystalline silicon are optimized.

Inventors

• ZHANG YOUHAI
• RUI YANG
• WANG LIGUANG
• YANG KAI
• CAO QIGANG
• WANG ZHONGBAO
• MA CHENG
• BAI YUAN

Assignees

• 宁夏中欣晶圆半导体科技有限公司

Dates

Publication Date

20260512

Application Date

20260327

Claims (10)

1. 1. The air guide heat insulation cover is characterized by comprising a hollow cavity which is penetrated in the axial direction, is sleeved at the bottom of the guide cylinder and is penetrated in the axial direction of the guide cylinder, wherein the bottom of the air guide heat insulation cover protrudes out of the bottom of the guide cylinder, and a through hole is formed in the side wall of the air guide heat insulation cover.
2. 2. The gas-conducting heat-insulating cover for enhancing uniformity of a single crystal product according to claim 1, wherein a distance between a bottom of the gas-conducting heat-insulating cover and a liquid surface of the silicon melt is 20-30mm.
3. 3. The air guide heat insulation cover for enhancing uniformity of monocrystalline products according to claim 2, wherein the air guide heat insulation cover comprises a connecting part and an air guide heat insulation part, the connecting part is in a round table shape, the diameter of the upper part of the connecting part is larger than the diameter of the bottom of the guide cylinder, the air guide heat insulation part is in a cylinder shape, the diameter of the air guide heat insulation part is smaller than the diameter of the bottom of the guide cylinder, and the bottom of the air guide heat insulation part protrudes out of the bottom of the guide cylinder.
4. 4. The air-guiding heat-insulating cover for enhancing uniformity of single crystal products according to claim 3, wherein a connecting piece is arranged on the inner side wall of the guide cylinder at a position corresponding to the connecting part, and the connecting part is connected with the connecting piece in a matching way.
5. 5. The cover of claim 4, wherein the connector includes a connection boss protruding from an inner sidewall of the guide shell.
6. 6. The gas-conducting heat-insulating cover for enhancing uniformity of single crystal products according to claim 1, wherein the gas-conducting heat-insulating cover is made of quartz.
7. 7. A method for enhancing uniformity of single crystal products is characterized in that before crystal pulling, an air guide heat insulation cover is sleeved at the bottom of a guide cylinder, the distance between the bottom of the air guide heat insulation cover and the liquid level of silicon melt is adjusted to be preset, and a crystal pulling program is started to correspondingly control the liquid opening distance and the pulling speed so that the ratio of the pulling speed to the temperature gradient is controlled to be within a critical value range.
8. 8. The method of claim 7, wherein the liquid port distance is 50-60mm.
9. 9. The method for enhancing uniformity of a single crystal product according to claim 8, wherein said pull rate is 0.5 to 0.6mm/s.
10. 10. A single crystal furnace, comprising a guide cylinder, wherein the guide cylinder is provided with the air guide heat shield as claimed in any one of claims 1 to 6.

Description

Air guide heat shield and method for enhancing uniformity of monocrystalline products and monocrystalline furnace Technical Field The invention relates to the technical field of semiconductor processing, in particular to a gas-guide heat shield for enhancing uniformity of monocrystalline products, a method and a monocrystalline furnace. Background Semiconductor single crystal silicon is used as a base material for integrated circuits and photovoltaic industry, and the crystal quality directly affects the device performance. In the Czochralski (Czochralski) single crystal growth process, melt convection, temperature distribution, and impurity transport are key factors affecting single crystal uniformity. The guide cylinder is an important component in the thermal field and mainly plays roles in air guiding and heat dissipation. The air guide is used for guiding the trend of the argon air flow through the guide cylinder so as to influence the transmission path of gaseous impurities, and the heat dissipation is used for shielding the heat radiated by part of the surrounding heaters through the guide cylinder so as to enable the monocrystalline silicon rod to form an axial temperature gradient. Therefore, the draft tube has a decisive influence on the uniformity of the single crystal by controlling the ‌ thermal field, the air flow field and the impurity transport process ‌. The traditional guide cylinder has limited thermal field adjusting capability, cannot accurately control axial temperature gradient, and the air guide relies on natural convection, so that the turbulence of the shielding gas causes the surface temperature fluctuation of crystals, the flowing of argon cannot effectively remove volatile dopants, and the impurity discharge efficiency is low. Disclosure of Invention In view of the above, the invention provides a gas-guide heat shield, a method and a single crystal furnace for enhancing uniformity of single crystal products, so as to solve the technical problems of limited thermal field adjusting capability and low impurity discharging efficiency of the traditional guide cylinder. The technical scheme adopted for solving the technical problems is as follows: the air guide heat shield for enhancing uniformity of monocrystalline products is provided with a hollow cavity which is penetrated in the axial direction, is sleeved at the bottom of the guide cylinder and is penetrated in the axial direction of the guide cylinder, wherein the bottom of the air guide heat shield protrudes out of the bottom of the guide cylinder, and the side wall of the air guide heat shield is provided with a through hole. Preferably, the distance between the bottom of the air-guide heat-insulating cover and the liquid level of the silicon melt is 20-30mm. The air guide heat insulation cover comprises a connecting part and an air guide heat insulation part, wherein the connecting part is in a round table shape, the diameter of the upper part of the connecting part is larger than the diameter of the bottom of the guide cylinder, the air guide heat insulation part is in a cylinder shape, the diameter of the air guide heat insulation part is smaller than the diameter of the bottom of the guide cylinder, and the bottom of the air guide heat insulation part protrudes out of the bottom of the guide cylinder. Preferably, a connecting piece is arranged on the inner side wall of the guide cylinder at a position corresponding to the connecting part, and the connecting part is connected with the connecting piece in a matching way. Preferably, the connecting piece comprises a connecting boss protruding from the inner side wall of the guide cylinder. Preferably, the air guide heat shield is made of quartz. The invention also provides a method for enhancing the uniformity of the monocrystalline product, which comprises the steps of sleeving the air guide heat insulation cover at the bottom of the guide cylinder before pulling, adjusting the distance between the bottom of the air guide heat insulation cover and the liquid level of the silicon melt, starting a pulling program, and correspondingly controlling the liquid opening distance and the pulling speed so as to control the ratio of the pulling speed to the temperature gradient in a critical value range. Preferably, the liquid opening distance is 50-60mm. Preferably, the pulling speed is 0.5-0.6mm/s. The invention also provides a single crystal furnace, which comprises a guide cylinder, wherein the guide cylinder is provided with the air guide heat shield. Compared with the prior art, the invention has the beneficial effects that: According to the invention, the air guide heat insulation cover is arranged on the guide cylinder, and the through holes are arranged on the side wall of the air guide heat insulation cover, so that effective heat insulation between ‌ heat shields and crystal bars and directional air flow guiding ‌ are realized, and the distribution of a thermal field and th