CN-122013304-A - Crystal pulling system for pulling heavily boron-doped silicon single crystal and control method thereof

CN122013304ACN 122013304 ACN122013304 ACN 122013304ACN-122013304-A

Abstract

The invention discloses a crystal pulling system for drawing a heavily-doped boron silicon single crystal and a control method thereof, wherein the crystal pulling system for drawing the heavily-doped boron silicon single crystal comprises a quartz crucible, a boron particle feeder, a heating device, a double-laser-induced breakdown spectroscopy measuring device and a model prediction controller, wherein the boron particle feeder is positioned above the liquid level of a melt in the quartz crucible and is used for supplementing boron particles to the surface of the melt; the dual-laser-induced breakdown spectroscopy measurement device comprises a first detection probe and a second detection probe, wherein the first detection probe is used for detecting the boron concentration of a melt in a nearby area where a crystal bar is in contact with the liquid level of the melt, and the second detection probe is used for detecting the carrier concentration of the grown crystal bar.

Inventors

ZHANG XINGMAO
WANG LIGUANG
ZHANG YOUHAI
YANG KAI
RUI YANG
MA CHENG
MA YINGJIAN
Shang Runlong

Assignees

宁夏中欣晶圆半导体科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260410

Claims (9)

1. A crystal pulling system for pulling a heavily boron-doped silicon single crystal, comprising a quartz crucible (100), a boron particle feeder (200), a heating device, a dual laser induced breakdown spectroscopy measurement device (400), and a model predictive controller (800), wherein: the boron particle feeder (200) is positioned above the melt liquid level in the quartz crucible (100) and is used for supplementing boron particles to the surface of the melt; The heating device comprises a temperature regulating piece (310), wherein the temperature regulating piece (310) is positioned above the liquid level of the melt and is used for regulating the temperature gradient of the melt in the quartz crucible (100) near a solid-liquid interface; The dual-laser-induced breakdown spectroscopy measurement device (400) comprises a first detection probe and a second detection probe, wherein the first detection probe is used for detecting the concentration of boron in a melt in a nearby area where a crystal bar contacts with the liquid level of the melt, and the second detection probe is used for detecting the concentration of carriers of the grown crystal bar; The boron particle feeder (200), the temperature regulating element (310), the first detection probe and the second detection probe are all connected with the model prediction controller (800), and the model prediction controller (800) controls the moving speed of the crystal bar along the axial direction, the feeding speed of the boron particle feeder (200) and the output power of the temperature regulating element (310) according to the melt boron concentration detected by the first detection probe and the carrier concentration detected by the second detection probe so that the deviation of the axial resistivity of the crystal bar and a preset axial resistivity target curve is within a preset range; the boron particle feeder (200) comprises an annular main body part (210) and a plurality of nozzles (220), wherein the annular main body part (210) is provided with an annular inner cavity, the plurality of nozzles (220) are arranged on the annular main body part (210) and are distributed at intervals along the annular main body part (210), the nozzles (220) are communicated with the annular inner cavity, the annular main body part (210) is used for encircling the outside of the crystal bar, and the nozzles (220) extend towards one side of the melt liquid level; The nozzle (220) is inclined toward the center side of the annular body portion (210).
2. The crystal pulling system for pulling a heavily boron-doped silicon single crystal of claim 1, wherein the angle between the central axis of the nozzle (220) and the plane of the melt level is greater than or equal to 60 ° and less than or equal to 80 °.
3. The crystal pulling system for pulling a heavily boron-doped silicon single crystal as set forth in claim 1, wherein the heating means further comprises a main heating member surrounding the quartz crucible (100) and opposed to the intermediate region of the quartz crucible (100), and an auxiliary heating member surrounding the quartz crucible (100) and opposed to the bottom region of the quartz crucible (100).
4. The crystal pulling system for pulling a heavily boron-doped silicon single crystal according to claim 1, further comprising a magnetic field adjusting device (500), the magnetic field adjusting device (500) being provided outside the quartz crucible (100) for applying a transverse magnetic field perpendicular to the melt level to the melt located in the quartz crucible (100).
5. The crystal pulling system for pulling a heavily boron-doped silicon single crystal of claim 4, wherein the magnetic field strength of said transverse magnetic field produced by said magnetic field adjusting means (500) is between 0.1T and 0.5T.
6. The crystal pulling system for pulling a heavily boron-doped silicon single crystal according to claim 1, further comprising a furnace body (600) and a cooling device (700), wherein the quartz crucible (100), the boron particle feeder (200), the heating device and the cooling device (700) are all located within the furnace body (600).
7. A control method of a crystal pulling system for pulling a heavily boron-doped silicon single crystal, characterized in that the crystal pulling system for pulling a heavily boron-doped silicon single crystal is the crystal pulling system for pulling a heavily boron-doped silicon single crystal as set forth in any one of claims 1 to 6, the control method comprising: In the equal-diameter growth stage, controlling the first detection probe to detect the concentration of boron in the melt in the vicinity of the contact of the crystal bar and the melt liquid surface, and controlling the second detection probe to detect the concentration of carriers of the grown crystal bar; and controlling the movement rate of the crystal bar along the axial direction, the feeding rate of the boron particle feeder (200) and the output power of the temperature regulating piece (310) according to the melt boron concentration detected by the first detection probe and the carrier concentration detected by the second detection probe so as to ensure that the deviation of the axial resistivity of the crystal bar and a target curve is in a preset range.
8. The control method according to claim 7, characterized in that the built-in process model of the model predictive controller (800) employs a one-dimensional diffusion-segregation coupling equation: ; Wherein C L is the concentration of boron in the melt in the vicinity of the contact of the crystal bar with the melt liquid surface, t is time, z is the position of the crystal bar axially away from the head of the crystal bar, V is the movement rate of the crystal bar axially, D eff is the effective diffusion coefficient, K eff is the effective segregation coefficient of boron, the effective segregation coefficient changes along with the temperature gradient G (t), R (t) is the feeding rate of the boron particle feeder, and V L is the volume of the melt.
9. The control method according to claim 7, wherein the preset axial resistivity target curve ρtarget (z) is: ; Wherein ρ 0 is the target resistivity of the head of the crystal bar, z is the position of the crystal bar axially away from the head of the crystal bar, Representing the axial resistivity change coefficient.

Description

Crystal pulling system for pulling heavily boron-doped silicon single crystal and control method thereof Technical Field The invention relates to the technical field of semiconductors, in particular to a crystal pulling system for drawing a heavily boron-doped silicon single crystal and a control method thereof. Background The heavily doped boron silicon single crystal (resistivity rho is less than or equal to 10m omega cm) is a core substrate material of semiconductor devices such as power devices, IGBT, super junction MOSFET and the like. With the development of high power and high integration of semiconductor devices, higher requirements are put on the axial uniformity of the resistivity of the semiconductor devices. In the process of growing the heavily boron-doped silicon single crystal by the Czochralski method, the effective segregation coefficient k eff apprxeq 0.8 of boron element in silicon, and k eff is sensitive to the crystal pulling rate and the temperature gradient near the solid-liquid interface. The related technology adopts fixed crystal pulling rate to match with post slicing grading when carrying out crystal pulling technology, and the fluctuation of melt temperature field is large in the technological process, so that the uniformity of the resistivity of the crystal bar in the axial direction is poor, the fragmentation rate in the subsequent sheet processing process is increased, and the performance of a semiconductor device is influenced. Disclosure of Invention The invention discloses a crystal pulling system for pulling a heavily boron-doped silicon single crystal and a control method thereof, which are used for solving the problem of poor uniformity of resistivity of a crystal bar in the axial direction in the crystal pulling process of the related technology. In order to solve the technical problems, the invention is realized as follows: The application discloses a crystal pulling system for drawing a heavily boron-doped silicon single crystal, the disclosed crystal pulling system for drawing a heavily boron-doped silicon single crystal comprises a quartz crucible, a boron particle feeder, a heating device, a double-laser-induced breakdown spectroscopy measurement device and a model predictive controller, wherein: the boron particle feeder is positioned above the liquid level of the melt in the quartz crucible and is used for supplementing boron particles to the surface of the melt; The heating device comprises a temperature regulating piece, wherein the temperature regulating piece is positioned above the liquid level of the melt and is used for regulating the temperature gradient of the melt in the quartz crucible near a solid-liquid interface; the dual-laser-induced breakdown spectroscopy measurement device comprises a first detection probe and a second detection probe, wherein the first detection probe is used for detecting the concentration of boron in a melt in a nearby area where a crystal bar contacts with the liquid level of the melt, and the second detection probe is used for detecting the concentration of carriers of the grown crystal bar; The model prediction controller controls the movement rate of the crystal bar along the axial direction, the feeding rate of the boron particle feeder and the output power of the temperature regulating element according to the melt boron concentration detected by the first detection probe and the carrier concentration detected by the second detection probe, so that the deviation of the axial resistivity of the crystal bar and a preset axial resistivity target curve is in a preset range. Optionally, the boron granule feeder includes annular main part and a plurality of nozzle, annular main part has annular inner chamber, and a plurality of the nozzle is located annular main part, and follows annular main part interval distribution, the nozzle with annular inner chamber intercommunication, annular main part is used for encircling outside the crystal bar, the nozzle orientation one side of fuse-element liquid level extends. Optionally, the nozzle is inclined towards a central side of the annular body portion, and an included angle between a central axis of the nozzle and a plane in which the melt level is located is greater than or equal to 60 ° and less than or equal to 80 °. Optionally, the heating device further comprises a main heating element and an auxiliary heating element, wherein the main heating element surrounds the outside of the quartz crucible and is opposite to the middle area of the quartz crucible, and the auxiliary heating element surrounds the outside of the quartz crucible and is opposite to the bottom area of the quartz crucible. Optionally, the crystal pulling system for pulling the heavily boron-doped silicon single crystal further comprises a magnetic field adjusting device, wherein the magnetic field adjusting device is arranged on the outer side of the quartz crucible and is used for applying a transverse magneti