TWI651440B - Single crystal furnace - Google Patents

Abstract

The invention provides a single crystal furnace, the single crystal furnace includes a long crystal furnace cavity and a control system, the control system includes a data acquisition module and a data processing module, and the data acquisition module collects the Real-time data in the crystal growth furnace cavity, the data processing module includes a simulation result database, the simulation result database is a complete crystal growth database constructed through simulation, and the single crystal growth is fully simulated , To obtain simulation data under different process conditions, you can immediately monitor and analyze the temperature distribution and flow field distribution of the single crystal furnace, and intelligently compare the data detected by the control system with the simulation results in the crystal database, Based on real-time data, the process is adjusted online in a timely manner, changing the traditional single control method, improving the control accuracy of the single crystal furnace, and improving the crystal quality of the single crystal.

Description

Single crystal furnace

The invention relates to the field of crystal growth, in particular to a single crystal furnace.

Artificial crystals are playing an increasingly important role in the fields of science and technology and industrial production. Especially single-crystal silicon, as a semiconductor material, is becoming more and more widely used in integrated circuits and other electronic components. Most of the existing single-crystal silicon is manufactured by the direct-draw method. In the traditional direct-draw method, usually before the single-crystal silicon grows, the operator sets the corresponding program in the control system of the single-crystal furnace, and then The control system of the single crystal furnace completes the growth process of the single crystal silicon step by step according to the program setting. This control system is a unidirectional control method with a single function. The growth of single crystal silicon depends basically on the professional experience and operating skills of the operator, and its product quality is relatively low. However, the market has higher and higher requirements for the crystal quality of large-size single-crystal silicon, so the accuracy of the control system for single-crystal furnaces has become increasingly stringent.

At present, due to the large amount of input during the growth of the single crystal silicon in the direct-draw method, the thermal field distribution in the single crystal furnace is very complicated, and the control system of the single crystal furnace is difficult to accurately present the actual thermal field distribution in the single crystal furnace; The entire growth process lasts from the seeding stage to the final finishing stage, and the control system of the single crystal furnace faces great challenges in the process stability and precise control of the space size in each stage.

Therefore, in view of the above technical problems, it is necessary to provide a new single crystal furnace.

The technical problem to be solved by the invention is to provide a single crystal furnace, which realizes the intelligent automatic control of the control system of the single crystal furnace, improves the control accuracy of the single crystal furnace, and improves the crystal quality of the single crystal.

In order to solve the above technical problems, the present invention provides a single crystal furnace for growing a single crystal. The single crystal furnace includes a long crystal furnace cavity and a control system. The control system includes a A data acquisition module for collecting data in the crystal growth furnace cavity, a data processing module for performing data analysis processing on the data and feedback a control signal, and a data acquisition module for feedback to the crystal growth furnace cavity An output module of the control signal; the data processing module includes a simulation result database and a data memory module, the simulation result database is a crystal growth database constructed by simulation; the data memory module The group is used to memorize real-time data collected by the crystal growth database and the data acquisition module.

Further, the single crystal furnace further includes a furnace body, a crucible provided in the furnace body and used for containing molten polycrystalline silicon material, and a pulling rod for pulling and rotating the single crystal.

Optionally, in the single crystal furnace, based on the geometric structure of the furnace body, a model is established according to the process parameters defined at each stage of the single crystal growth, and calculation is performed using a crystal growth simulation software. As a result, the crystal growth database is established.

Further, in the single crystal furnace, the crystal growth database includes process parameters defined at different stages of single crystal growth based on the geometry of the furnace body, and different stages of the single crystal growth. The temperature distribution map or temperature distribution curve in the furnace body, and the corresponding flow field analysis in the furnace during each stage of the single crystal growth. Layout or flow field distribution curve.

Further, in the single crystal furnace, the data processing module searches, compares, and analyzes the real-time data in the crystal growth database, and returns a control signal, where the control signal is the Defined process parameters for the next moment of single crystal growth.

Optionally, in the single crystal furnace, the data memory module is divided into a first data memory module and a second data memory module, and the first data memory module stores the crystal growth database, The second data memory module stores the real-time data.

Further, in the single crystal furnace, real-time data update of the second data memory module and optimization of the crystal growth database of the first data memory module.

Further, in the single crystal furnace, the long crystal furnace cavity includes a crystal control module and a pot control module, and the crystal control module is used to adjust the pulling speed and the rotation speed of the single crystal. The pot control module is used to adjust the temperature in the crucible, the lifting speed of the crucible, and the speed of the crucible.

Optionally, in the single crystal furnace, the data acquisition module includes a crystal position sensor for monitoring the position of the single crystal, a pot position sensor for monitoring the position of the crucible, a A temperature sensor that measures the temperature in the crucible in real time, the data acquisition module collects the pulling speed data and single crystal speed data of the single crystal, the lifting speed data and crucible speed data of the crucible, and the data in the crucible. Temperature data.

Further, in the single crystal furnace, the crystal control module includes a crystal raising motor that controls the pulling rod to pull the single crystal and a crystal rotating motor that controls the rotation of the single crystal.

Further, in the single crystal furnace, the pot control module includes a pot rotating motor that controls the crucible rotation, a pot lifting motor that controls the crucible lifting, and the crucible A heated heating module and a temperature control module for controlling the heating module according to the temperature in the crucible.

Further, in the single crystal furnace, the long crystal furnace cavity further includes a gas pressure control module that controls the gas pressure in the furnace.

Further, in the single crystal furnace, the data acquisition unit further includes a pressure detector for collecting a pressure value of the furnace body.

Optionally, in the single crystal furnace, the control system further includes an alarm module for prompting and recording fault information during the growth of the single crystal.

Optionally, in the single crystal furnace, the control system further includes a display module for displaying the real-time data and the control signal.

Compared with the prior art, the present invention has the following beneficial effects: the present invention comprehensively simulates the growth of the single crystal through the simulation result database in the single crystal furnace, obtains simulation data under different process conditions, and can be monitored and analyzed in real time The temperature distribution and flow field distribution of the single crystal furnace overcome the defect that it is difficult to control the actual thermal field distribution in the single crystal furnace in the prior art, improve the control accuracy of the single crystal furnace, and improve the crystal quality of the single crystal. .

Further, based on the geometric structure of the furnace body, a model is established according to process parameters defined in each stage of the single crystal growth, calculation is performed using a crystal growth simulation software, and the crystal growth database is established using the calculation results, The theoretical simulation data in the crystal growth database is more accurate and more valuable; meanwhile, the data detected by the control system (that is, real-time data collected by the data acquisition module) and the crystal growth data The simulation results in the library are compared intelligently and interactively. Based on the real-time data, the process can be adjusted online and changed in a timely manner. The traditional single control method realizes the analysis and optimization control of the single crystal growth process, improves the control accuracy of the single crystal furnace, and further improves the crystal quality of the single crystal.

In addition, the real-time data is stored in a second data memory module. During the growth of the single crystal, the data of the second data memory module can be continuously optimized and updated according to analysis and judgment. The crystal growth database of the group is formed to form a good interactive iterative operation, which makes the crystal growth database and the single crystal growth process mature and perfect. After reaching a certain level, the intelligent automatic control of the single crystal furnace based on the crystal growth database can be realized By self-adjusting the temperature and flow field during the growth of the single crystal, the growth of each single crystal is in a highly automated state, saving costs and improving the crystal quality of the single crystal.

1‧‧‧Crystal Furnace

2‧‧‧Control System

11‧‧‧ Crystal Control Module

12‧‧‧ pot control module

13‧‧‧Air pressure control module

111‧‧‧Jingsheng Motor

112‧‧‧ Crystal Turn Motor

121‧‧‧ Cauldron Motor

122‧‧‧ Pot Rotary Motor

123‧‧‧Heating Module

124‧‧‧Temperature Control Module

21‧‧‧Data Acquisition Module

22‧‧‧Data Processing Module

23‧‧‧Output Module

211‧‧‧ Epitaxial sensor

212‧‧‧ Pot Sensor

213‧‧‧Temperature sensor

214‧‧‧Air Pressure Detector

221‧‧‧ Simulation Results Database 1

222‧‧‧Data Memory Module

2221‧‧‧First Data Memory Module

2222‧‧‧Second data memory module

24‧‧‧Display Module

25‧‧‧Alarm module

FIG. 1 is a schematic structural diagram of a single crystal furnace according to an embodiment of the present invention; and FIG. 2 is a frame structural diagram of a control system of the single crystal furnace according to an embodiment of the present invention.

The inventor found that during the growth of the single crystal in the prior art, the operator could not know the actual temperature gradient distribution of the single crystal furnace, the distribution of the air flow field, etc. The crystal quality of a single crystal has a decisive influence. At the same time, the inventor also learned that simulation technology is becoming more and more widely used in research and development and production. With the improvement of computer performance and the introduction of various optimization algorithms, the simulation speed is faster and the results more accurate. Therefore, the inventors studied the corresponding analog software to perform quasi-steady-state and dynamic simulation, which can accurately obtain the temperature distribution, gas flow field distribution in the single crystal furnace, and reflect the single crystal oxygen species. Information such as the mass distribution and the defect distribution of the single crystal can be used to obtain accurate information about the growth process of the single crystal. The inventor believes that it is of great significance to apply it to the actual growth of the single crystal silicon, which is beneficial to improving the single crystal furnace. Control precision to achieve single crystal growth with high crystal quality.

Therefore, based on the above research and discovery, the present invention provides a single crystal furnace for growing a single crystal. The single crystal furnace includes a long crystal cavity and a control system. The control system includes a A data acquisition module for collecting data in the crystal growth furnace cavity, a data processing module for data analysis and processing of the data and feedback of a control signal, and a data processing module for the growth of the crystal growth furnace cavity An output module for feedbacking the control signal; the data processing module includes a simulation result database and a data memory module, and the simulation result database is a crystal growth database constructed by simulation; the data The memory module is configured to memorize real-time data collected by the crystal growth database and the data acquisition module.

The invention comprehensively simulates the growth of the single crystal through the simulation result database in the single crystal furnace, obtains simulation data under different process conditions, and can instantly monitor and analyze the temperature distribution and flow field distribution of the single crystal furnace. In order to overcome the defect that it is difficult to control the actual thermal field distribution in the single crystal furnace in the prior art, the control accuracy of the single crystal furnace is improved, and the crystal quality of the single crystal is improved.

The single crystal furnace of the present invention will be described in more detail with reference to the structure diagram and the flowchart, which shows the preferred embodiment of the present invention. It should be understood that those skilled in the art can modify the invention described herein while still realizing the invention. Beneficial effects. Therefore, the following description should be understood as widely known to those skilled in the art, and not as a limitation on the present invention.

The invention is described in more detail by way of example in the following paragraphs with reference to the drawings. root The advantages and features of the present invention will become clearer from the following description and claims. It should be noted that the drawings are in a very simplified form and all use inaccurate proportions, which are only used to facilitate and clearly assist the description of the embodiments of the present invention.

The following is an example of the single crystal furnace that uses the single crystal silicon grown by the direct pulling method as an example to clearly explain the content of the present invention. It should be clear that the content of the present invention is not limited to the following examples. The improvement of the conventional technical means of the skilled person is also within the scope of the present invention.

First, please refer to FIG. 1, which is a schematic diagram of a single crystal furnace according to an embodiment of the present invention. The single crystal furnace is used for the growth of a single crystal silicon. The single crystal furnace includes a furnace body. A crucible provided in the furnace body for containing molten polycrystalline silicon material, and a pull rod for pulling and rotating the single crystal silicon, the single crystal furnace further comprising a long crystal furnace cavity 1 and a control system 2. The crystal growth chamber 1 includes a crystal control module 11, a pot control module 12, and a gas pressure control module 13. The crystal control module 11 includes a control lever for pulling the monocrystalline silicon. A crystal-lifting motor 111 and a crystal-rotating motor 112 that controls the rotation of the single crystal silicon; the pot control module 12 includes a pot-lifting motor 121 that controls the lifting of the crucible, and a pot-rotating motor that controls the rotation of the crucible 122. A heating module 123 for heating the crucible, and a temperature control module 124 for controlling the heating module 123 according to the temperature in the crucible; the air pressure control module 13 is used to adjust the furnace body. Pressure, the inert gas such as argon is used as the protective gas in the process of preparing the single crystal silicon by the direct-drawing method to form an argon flow under a reduced pressure atmosphere. In order to prevent oxide particles from falling into the silicon melt and then moving to the solid-liquid interface, the uniformity of the single crystal silicon atom arrangement is destroyed; on the other hand, it can take away the temperature during the growth process and promote the heat dissipation and cooling of the single crystal silicon. .

As shown in FIG. 2, FIG. 2 is a frame structure diagram of the control system of the single crystal furnace in the embodiment of the present invention. In the present embodiment, the control system 2 of the single crystal furnace includes a A data acquisition module 21 for data in the crystal growth chamber 1, a data processing module 22 for data analysis and processing of the data to output a control signal, and a data processing module 22 for the growth of the crystal growth chamber 1 The output module 23 returns the control signal. The data acquisition module 21 includes a crystal bit sensor 211, a pot bit sensor 212, a temperature sensor 213, and a pressure detector 214. The data acquisition module 21 can collect data through the crystal position sensor 211. To the pulling speed data of the single crystal silicon (the pulling speed data is obtained by detecting the position and growth time of the single crystal silicon by the crystal position sensor 211), similarly, by the pot position The sensor 212 can obtain the speed data of the crucible lifting, the temperature value in the crucible can be measured in real time by the temperature sensor 213, and the air pressure value in the furnace can be detected in real time by the air pressure detector 214. Of course, the data acquisition module 21 may also collect single crystal speed data of the crystal rotation motor 112 controlling the single crystal silicon rotation and crucible speed data of the crucible rotation motor 122 controlling the crucible rotation.

The data processing module 22 performs data analysis and processing based on the real-time data collected by the data acquisition module 21 and returns a control signal. The data processing module 22 includes a simulation result database 221 and a data memory module. 222, Preferably, the simulation result database 221 is a crystal growth database constructed by simulation, based on the geometric structure of the furnace body, and according to the process parameters defined in each stage of the growth of the single crystal silicon (Such as the pressure of the furnace body, the pulling speed of the single crystal and the speed of the single crystal, the temperature value in the crucible, the speed of the crucible, the speed of the crucible, and the speed of the crucible, and the time of each stage of the growth of the single crystal silicon Etc.) A model is established, calculation is performed using a crystal growth simulation software, and the crystal growth database is established using the calculation results. For example, the crystal growth database may include different definitions of each stage of the single crystal silicon growth. Process parameters, different temperature distribution maps or temperature distribution curves in the furnace body at different stages of the single crystal silicon growth, and corresponding flow field distribution maps or flow field distribution curves, because the temperature distribution in the furnace body The information about the distribution of oxygen impurities in the single crystal silicon, the distribution of the defects of the single crystal silicon itself, and the thermal stress of the single crystal silicon can be known with the distribution of the flow field. The data memory module 222 can be divided into a first data memory module 2221 and a second data memory module 2222. The first data memory module 2221 stores the crystal growth database and the second data memory module. Group 2222 memorizes the instant data.

The data processing module 22 searches, compares and analyzes the real-time data in the crystal growth database, and intelligently retrieves the definition of the next moment of growth of the single crystal silicon from the crystal growth database. Process parameters (i.e. the pressure of the furnace body required at the next moment, the pulling speed of the single crystal and the speed of the single crystal, the temperature in the crucible, the speed of the crucible, the speed of the crucible, and the speed of the crucible. The time of each stage of single crystal silicon growth is described), and the corresponding defined process parameters (ie, control signals) are fed back. The data processing module 22 completes the intelligent interactive comparison between the real-time data and the simulation results in the crystal growth database, and based on the real-time data, adjusts the process online in a timely manner.

The output module 23 feeds back the control signal fed back by the data processing module 22 to the corresponding module in the crystal growth chamber 1, and the corresponding module in the crystal growth chamber 1 is based on the received information. The control signal performs a growth operation of the single crystal silicon at the next moment.

In this way, the single crystal furnace repeats the data acquisition module 21 to collect the data of the long crystal furnace cavity 1, the data processing module 22 analyzes and processes the data and returns a control signal, and the output module 23 The process of feeding back the control signal to the growth chamber 1 until the growth of the single crystal silicon ends.

At the same time, each time the single crystal silicon is grown, the content of the crystal growth database is verified or optimized, and the results of the data detected by the control system (that is, the real-time data) are continuously optimized and updated by judging and analyzing the data results detected by the control system. The crystal growth database is used to form a good interactive iterative operation, so that both the crystal growth database and the single crystal growth process become mature and perfect.

Of course, in order to clearly understand the various process parameters in different growth stages of the single crystal silicon, the control system 2 further includes a display module 24, which simultaneously displays the real-time data and the control. signal. At the same time, during the growth of the single crystal silicon, the control system 2 further includes an alarm module 25, and the alarm module 25 prompts and records fault information during the growth of the single crystal silicon. The crystal furnace will also be equipped with a manual switch for emergency shutdown in the event of a failure. These are all known and understandable by those of ordinary skill in the art, and will not be repeated here.

Therefore, when the single crystal silicon is grown using the single crystal furnace in the embodiment of the present invention, the growth of the single crystal silicon is comprehensively simulated through the simulation result database 221 in the single crystal furnace to obtain different process conditions. The simulation data can be used to monitor and analyze the temperature distribution and flow field distribution of the single crystal furnace in real time, to overcome the defect that the actual thermal field distribution in the single crystal furnace is difficult to control in the prior art; and, the control system 2 The detected data is intelligently compared with the simulation results in the crystal growth database. Based on the real-time data, the process is adjusted online in a timely manner to change the traditional singular control method to achieve the single crystal silicon. The analysis and optimization control of the growth process improves the control accuracy of the single crystal furnace and the crystal quality of the single crystal silicon.

In summary, the present invention comprehensively simulates the growth of the single crystal through the simulation result database in the single crystal furnace, obtains simulation data under different process conditions, and can monitor and analyze the temperature distribution and temperature of the single crystal furnace in real time. The flow field distribution overcomes the defect that it is difficult to control the actual thermal field distribution in the single crystal furnace in the prior art, improves the control accuracy of the single crystal furnace, and improves High crystal quality of single crystal.

Further, based on the geometric structure of the furnace body, modeling according to the process parameters defined in each stage of the single crystal growth, using a crystal growth simulation software for calculation, and using the calculation results to establish the crystal growth database, The theoretical simulation data in the crystal growth database is more accurate and more valuable; meanwhile, the data detected by the control system (that is, real-time data collected by the data acquisition module) and the crystal growth data The simulation results in the library are compared intelligently, based on the real-time data, the process is adjusted online in a timely manner, the traditional single control method is changed, the analysis and optimization control of the single crystal growth process is realized, and the single crystal is improved Furnace control accuracy further improves the crystal quality of single crystal.

In addition, the real-time data is stored in a second data memory module. During the growth of the single crystal, the data of the second data memory module can be continuously optimized and updated according to analysis and judgment. The crystal growth database of the group is formed to form a good interactive iterative operation, which makes the crystal growth database and the single crystal growth process mature and perfect. After reaching a certain level, the intelligent automatic control of the crystal growth furnace based on the crystal growth database can be realized. By self-adjusting the temperature and flow field during the growth of the single crystal, the growth of each single crystal is in a highly automated state, saving costs and improving the crystal quality of the single crystal.

Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. In this way, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (13)

A single crystal furnace is used for the growth of a single crystal, wherein the single crystal furnace includes a crystal growth chamber and a control system; the control system includes a method for collecting A data acquisition module for data, a data processing module for analyzing the data and returning a control signal, and an output module for returning the control signal to the growth chamber; The data processing module includes a simulation result database and a data memory module. The simulation result database is a crystal growth database constructed by simulation. The data storage module is used to memorize the growth crystal. The database and the real-time data collected by the data acquisition module, wherein the single crystal furnace further includes a furnace body, a crucible set in the furnace body for holding molten polycrystalline silicon material, and used for pulling and rotating the A single crystal lifting rod and the crystal growth cavity include a crystal control module and a pot control module, the crystal control module is used to adjust the pull speed of the single crystal and the rotation speed of the single crystal, and the pot control mold Set for adjusting the crucible The temperature, the speed of the crucible and the crucible lifting speed. The single crystal furnace according to claim 1, wherein the geometric structure of the furnace body is used as a basis for modeling according to the process parameters defined in each stage of the single crystal growth, and calculation is performed using a crystal growth simulation software. As a result, the crystal growth database is established. The single crystal furnace according to claim 2, wherein the crystal growth database includes process parameters defined at different stages of the single crystal growth based on the geometry of the furnace body, and different single crystal growth The temperature distribution diagram or temperature distribution curve in the furnace body in each stage, and the corresponding flow field distribution diagram or flow field distribution curve in the furnace body in the different stages of the single crystal growth. The single crystal furnace according to claim 3, wherein the data processing module searches, compares, and analyzes the real-time data in the crystal growth database, and returns a control signal, and the control signal is The defined process parameters for the next moment of single crystal growth are described. The single crystal furnace according to any one of claims 1 to 4, wherein the data memory module is divided into a first data memory module and a second data memory module, and the first data memory module stores The crystal growth database, and the second data memory module stores the real-time data. The single crystal furnace according to claim 5, wherein the real-time data update of the second data memory module and optimization of the crystal growth database of the first data memory module. The single crystal furnace according to claim 1, wherein the data acquisition module includes a crystal position sensor for monitoring the position of the single crystal, a pot position sensor for monitoring the position of the crucible, a A temperature sensor that measures the temperature in the crucible in real time, the data acquisition module collects the pulling speed data and single crystal speed data of the single crystal, the lifting speed data and crucible speed data of the crucible, and the data in the crucible. Temperature data. The single crystal furnace according to claim 1, wherein the crystal control module includes a crystal lifting motor that controls the pull rod to pull the single crystal and a crystal rotation motor that controls the rotation of the single crystal. The single crystal furnace according to claim 1, wherein the pot control module includes a pot rotating motor that controls the crucible rotation, a pot lifting motor that controls the crucible lifting, and a heating mold for heating the crucible. And a temperature control module that controls the heating module according to the temperature in the crucible. The single crystal furnace according to claim 1, wherein the long crystal furnace cavity further includes a gas pressure control module that controls the gas pressure in the furnace. The single crystal furnace according to claim 10, wherein the data acquisition unit further includes a pressure detector for collecting a pressure value of the furnace body. The single crystal furnace according to claim 1, wherein the control system further includes an alarm module for prompting and recording fault information during the growth of the single crystal. The single crystal furnace according to claim 1, wherein the control system further includes a display module for displaying the real-time data and the control signal.