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CN-122013300-A - Czochralski silicon single crystal growth method and device for cooperatively controlling bulk micro defects and silicon wafer

CN122013300ACN 122013300 ACN122013300 ACN 122013300ACN-122013300-A

Abstract

The present disclosure provides a method and apparatus for growing Czochralski silicon single crystal with co-controlled bulk micro-defects, and a silicon wafer. The method implements a ternary cooperative control strategy of nitrogen-oxygen-vacancy in the crystal pulling process, and specifically comprises the steps of calculating nitrogen doping amount in a charging stage, controlling the rotating speed and the airflow field of a crucible in a melting and stabilizing stage to adjust oxygen content, and shaping a thermal field by using an inverted cone-shaped guide cylinder in a constant diameter growth stage. And locking the V/G ratio of the solid-liquid growth interface of the silicon single crystal in the pure vacancy defect generating area by executing pull-speed locking logic. The application limits the nitrogen concentration in the crystal to a low concentration range of 1X 10 13 to 5X 10 13 atoms/cm 3 , simultaneously controls the oxygen concentration to 11 to 13ppma, and utilizes the high concentration vacancy of the pure vacancy area to compensate the insufficient nucleation power under the condition of low nitrogen, thereby realizing the realization of high-density and radial uniform distribution of bulk micro defects while inhibiting nitrogen related defects and improving the gate oxide integrity of the silicon wafer.

Inventors

  • MAO QINHU

Assignees

  • 西安奕斯伟材料科技股份有限公司

Dates

Publication Date
20260512
Application Date
20260324

Claims (10)

  1. 1. A method for growing a czochralski silicon single crystal with co-controlled bulk micro-defects, the method comprising: Doping nitrogen dopant into silicon melt of the single crystal furnace to make nitrogen concentration of grown silicon single crystal be 1×10 13 atoms/cm 3 -5×10 13 atoms/cm 3 ; Adjusting process parameters such that the interstitial oxygen concentration of the silicon single crystal is 11ppma to 13ppma; And in the equal-diameter growth stage, regulating the thermal field distribution of the single crystal furnace, executing a pull-speed locking process, and locking the V/G ratio of the solid-liquid growth interface of the silicon single crystal in a pure vacancy defect generation area, wherein V is the pull-speed, and G is the axial temperature gradient.
  2. 2. The method for growing a czochralski silicon single crystal with co-controlled bulk micro-defects of claim 1, wherein the pull rate locking process comprises: obtaining a critical V/G value under a current thermal field structure, wherein the critical V/G value corresponds to the boundary of a vacancy dominant region and a interstitial dominant region; Setting a target lifting speed, so that a V/G value corresponding to the target lifting speed is larger than the critical V/G value and smaller than the lower limit V/G value of the cavity defect generation area; When the fluctuation of the crystal diameter is detected, the power of the heater is regulated to correct the diameter, and the change amplitude of the target pulling speed is maintained within a preset threshold.
  3. 3. The method for growing a czochralski silicon single crystal of co-controlled bulk micro defect of claim 2, wherein the variation amplitude of the target pulling rate is limited to within a range of ±0.05 mm/min.
  4. 4. The method for growing a Czochralski silicon single crystal with co-controlled bulk micro-defect of claim 1, wherein the adjusting the thermal field distribution of the single crystal furnace comprises providing an inverted cone-shaped guide cylinder at the periphery of the silicon single crystal growth path, wherein the ratio of the diameter of the lower end opening of the inverted cone-shaped guide cylinder to the target diameter of the silicon single crystal is 1.1 to 1.3.
  5. 5. The method for growing a Czochralski silicon single crystal with co-controlled bulk micro defect according to claim 4, wherein the level position of the silicon melt is monitored in real time and the crucible elevation speed is adjusted during the constant diameter growth stage so as to maintain the vertical distance between the lower end opening of the inverted cone-shaped guide cylinder and the level of the silicon melt to be constant in the range of 20mm to 30 mm.
  6. 6. The method for growing a czochralski silicon single crystal with co-control of bulk micro-defects according to claim 1, wherein the rotation speed of the crucible assembly containing the silicon melt is controlled between 5rpm and 8rpm to adjust the interstitial oxygen concentration.
  7. 7. The method for growing a Czochralski silicon single crystal with co-controlled bulk micro-defect of claim 1, further comprising controlling the passage of the silicon single crystal through a temperature zone of 1100 ℃ to 800 ℃ according to a preset cooling history to control the long and large size of oxygen precipitation.
  8. 8. The method for growing a czochralski silicon single crystal with co-controlled bulk micro-defects of claim 1, wherein the nitrogen dopant is a silicon wafer with a silicon nitride film layer or a highly nitrogen doped silicon master alloy.
  9. 9. A czochralski silicon single crystal growing apparatus for co-controlling bulk micro defects, wherein the apparatus is for performing the method of any one of claims 1 to 8, the apparatus comprising: a furnace body; the crucible assembly is arranged in the furnace body and is used for accommodating the silicon melt; A heater for heating and melting the silicon melt in the crucible assembly; a pulling mechanism for pulling up a grown silicon single crystal from the silicon melt, and And a control unit connected to the heater, the pulling mechanism and the crucible assembly, the control unit being configured to control an addition amount of a nitrogen dopant such that a nitrogen concentration of a grown silicon single crystal is 1×10 13 atoms/cm 3 to 5×10 13 atoms/cm 3 , to adjust a process parameter such that a interstitial oxygen concentration of the silicon single crystal is 11ppma to 13ppma, to adjust a thermal field distribution of the single crystal furnace and to perform a pulling rate locking process during an equal diameter growth stage, and to lock a V/G ratio of a solid-liquid growth interface of the silicon single crystal at a pure vacancy defect generating region.
  10. 10. A silicon wafer, characterized in that it is produced by a method according to any one of claims 1 to 8, said silicon wafer having the following parametric characteristics: Nitrogen concentration ranges from 1 x 10 13 atoms/cm 3 to 5 x 10 13 atoms/cm 3 ; a interstitial oxygen concentration of 11ppma to 13ppma; The density of the body micro defects is 1X 10 13 /cm 3 to 5X 10 13 /cm 3 ; the fluctuation rate of the bulk micro defect density in the radial direction of the silicon wafer is less than 5%.

Description

Czochralski silicon single crystal growth method and device for cooperatively controlling bulk micro defects and silicon wafer Technical Field The disclosure relates to the technical field of semiconductor material preparation, in particular to a Czochralski silicon single crystal growth method and device for cooperatively controlling bulk micro defects and a silicon wafer. Background In the field of semiconductor integrated circuit fabrication, silicon single crystals grown by the Czochralski (CZ) method are currently the dominant substrate materials. With the continuous miniaturization of device process nodes (for example, 14nm, 7nm and more advanced nodes), the defect control requirement on the inside of a silicon wafer reaches higher standards. Among them, bulk micro defects (Bulk Micro Defects, BMD) are one of the most important micro defects inside a silicon wafer, and are mainly composed of oxygen precipitates (Oxygen Precipitates, siO x). The proper amount of BMD can form an internal gettering (INTRINSIC GETTERING, IG) effect, so that heavy metal impurities introduced in the process are effectively captured, and the active region of the device is purified. However, the formation and distribution of BMDs are complicated by thermal history and impurity concentrations during crystal growth. In order to enhance the mechanical strength of the wafer and promote the formation of BMD, nitrogen Doping (Nitrogen dopping) processes are commonly used in the art. Nitrogen atoms are able to pin dislocations in the silicon lattice and act as heterogeneous cores to reduce nucleation barriers for oxygen precipitation. Thus, conventional processes typically incorporate higher concentrations of nitrogen (e.g., above 1 x 101 4atoms/cm3) to ensure that a high density of BMD is obtained. In this way, while the gettering ability is maintained, side effects are also introduced. In particular, an increase in nitrogen concentration changes the balance of point defects and may lead to the formation of complex nitrogen-oxygen complexes. However, the conventional working method has a core technical problem that the radial uniformity and density of the BMD cannot be maintained while suppressing the Nitrogen related defects (Nitrogen RELATED DEFECTS, such as NDP). In particular, when the nitrogen concentration is too high (e.g., in excess of 5X 10 13atoms/cm3), the nitrogen atoms tend to polymerize to form stable clusters or combine with vacancies to form defects that can cause nitrogen defect pits (NitrogenDefectPit, NDP) in the wafer surface during subsequent high temperature processing. When NDP is located at the gate oxide of the device, the integrity of the oxide is severely damaged, resulting in device leakage, which can affect the device performance of the prior art process. To solve the NDP problem, the nitrogen concentration must be reduced. However, when the nitrogen concentration is lowered, the nucleation kinetics of BMD are insufficient, resulting in a significant decrease in BMD density and uneven distribution, typically exhibiting a high center and low edge distribution, and the fluctuation rate often exceeds 20%. Such non-uniformity results in poor mechanical strength and poor gettering capability at the wafer edge region, and fails to meet the requirements for full wafer yield uniformity. Therefore, how to obtain high-density and uniform BMD under low nitrogen concentration is a technical problem to be solved urgently. Disclosure of Invention The application aims to solve the technical problem that the density and uniformity of a nitrogen-related defect NDP and a micro defect BMD of a retainer cannot be simultaneously inhibited in the existing nitrogen-doped czochralski silicon single crystal growth technology, and provides a czochralski silicon single crystal growth method and device based on a ternary cooperation mechanism and a silicon wafer. According to the technical scheme, the distribution proportion of nitrogen, oxygen and vacancies can be realized through hardware structure control and full-flow process logic locking, so that the silicon wafer is ensured to have BMD which is radially and uniformly distributed and has moderate density while NDP is inhibited. The technical scheme of the present disclosure is realized as follows: In a first aspect, the present disclosure provides a method of growing a czochralski silicon single crystal with synergistic control of bulk micro defects, the method comprising: Doping nitrogen dopant into silicon melt of the single crystal furnace to make nitrogen concentration of grown silicon single crystal be 1×10 13atoms/cm3 -5×10 13atoms/cm3; Adjusting process parameters such that the interstitial oxygen concentration of the silicon single crystal is 11ppma to 13ppma; And in the equal-diameter growth stage, regulating the thermal field distribution of the single crystal furnace, executing a pull-speed locking process, and locking the V/G ratio of the solid-liquid growth inte