A device for growing a semiconductor crystal material and a method for growing the same

Abstract

The application discloses a kind of growth device and its growth method of semiconductor crystal material, the device and growth method can detect crack generated in the process of crystal growth or after cooling down after growth;Device can use the high-temperature reaction furnace of traditional HVPE method, connect below the quartz tray of traditional high-temperature reaction furnace by double-layer connecting rod, have resonant cavity and piezoelectric transducer in double-layer connecting rod, can collect and amplify the acoustic wave signal of crystal on tray vibration when crack is generated in the process of growth or cooling down, and convert the signal collected into electrical signal, to detect whether crystal has crack generation;Through the device and method, it can be determined that crack is generated in which stage, and the corresponding process is improved, unnecessary raw material and time cost waste can be reduced.

Description

Technical Field

[0001] This invention relates to a semiconductor crystal material growth apparatus and method, belonging to the field of semiconductor material manufacturing, and particularly to crystal growth process control technology. Background Technology

[0002] During the semiconductor material growth process, cracks may develop in the crystal due to process variations or other reasons. Most of these cracks render the crystal unusable. Continuing the process under these conditions would result in unnecessary waste of raw materials and time. Therefore, online monitoring of crystal crack formation and timely intervention are crucial for cost control in industrial production.

[0003] In the crystal growth process, online monitoring typically presents the following challenges: ① Monitoring is difficult because the high temperature and corrosive gases inside the reaction chamber make it challenging to acquire image signals via camera. ② Detection signals are also difficult because crystal cracks are usually caused by stress concentration. When the internal stress exceeds the crystal's internal bonding force (van der Waals force), the crystal will crack along a certain direction, generating vibrational sound waves of a specific frequency. However, due to the varying sizes of the cracks, the intensity (frequency and amplitude) of these vibrational sound waves differs, making it difficult to detect the intensity of the sound waves.

[0004] In the existing technology, due to the lack of a step for detecting crystal cracks, after the crystal is taken out of the reactor, it is found that the crystal has cracked, but it is unclear at which stage (such as the crystal growth stage or the cooling stage after the crystal growth is completed) or which step the crack was generated. This makes it difficult to provide a good solution for subsequent crack prevention.

[0005] Therefore, there is an urgent need for a device or system capable of real-time detection of crystal growth crack defects. Summary of the Invention

[0006] To address the aforementioned technical problems, the objective of this invention is to propose a semiconductor crystal material growth apparatus and method, and to develop an online crystal growth monitoring system on existing HVPE equipment.

[0007] To address the aforementioned problems, this invention provides a semiconductor crystal material growth apparatus that can monitor for crack formation during the crystal growth and cooling processes. Growth can be terminated immediately upon detection of cracks in the wafer, reducing time and material waste associated with subsequent growth of defective wafers. Furthermore, since wafer cracks typically occur in two stages: first during growth, and second during the subsequent cooling process, the crack defect detection system can determine at which stage the crack occurs and allow for adjustments to subsequent processes, such as adjusting the growth or cooling steps.

[0008] The technical solution of this invention is implemented as follows: A semiconductor crystal material growth apparatus includes a growth furnace and a signal processing system located outside the growth furnace. A tray is disposed inside the growth furnace, and a double-layer connecting rod is connected to the tray. The double-layer connecting rod includes an inner resonant thin-walled structure and an outer resonant thin-walled structure. The outer resonant thin-walled structure is connected and fixed to the inner resonant thin-walled structure via multiple connecting pins. The space between the outer and inner resonant thin-walled structures forms an outer resonant cavity, and the inner space of the inner resonant thin-walled structure forms an inner resonant cavity. A piezoelectric transducer is disposed in the inner resonant cavity, and the piezoelectric transducer is fixedly connected to the inner resonant thin-walled structure and electrically connected to the signal processing system. The tray is used to support the crystal. The physical signals generated by the crystal during growth and / or cooling are transmitted to the piezoelectric transducer via the double-layer connecting rod and fed back to the signal processing system by the piezoelectric transducer.

[0009] Preferably, the tray and the double-layer connecting rod are made of the same material.

[0010] Preferably, both the tray and the double-layer connecting rod are made of quartz.

[0011] Preferably, the outer diameter of the inner resonant thin-walled structure is 28-35mm and the wall thickness is 0.5-0.8mm; the outer diameter of the outer resonant thin-walled structure is 45-55mm and the wall thickness is 0.5-0.8mm; and the diameter of the connecting pin is 1-5mm.

[0012] Preferably, both the inner resonant thin-walled structure and the outer resonant thin-walled structure have symmetrical cross-sections, and the centerline of the inner resonant thin-walled structure and the centerline of the outer resonant thin-walled structure are on the same straight line.

[0013] Preferably, the piezoelectric transducer is located at the center of the inner resonant cavity, and the piezoelectric transducer is fixedly connected to the inner resonant thin-walled structure via a fixed shaft; a scattering plate is provided on the inner wall of the inner resonant thin-walled structure at the position corresponding to the connecting pin.

[0014] Preferably, the scattering plate has a cross structure and is made of bronze.

[0015] Preferably, the piezoelectric transducer is located in the part of the double-layer connecting rod inside the growth furnace body, and the double-layer connecting rod is provided with a heat insulation structure outside the location of the piezoelectric transducer; the upper end of the double-layer connecting rod is connected to the tray, the lower end of the double-layer connecting rod extends to the outside of the growth furnace body, and the signal processing system is electrically connected to the piezoelectric transducer through the lower end of the double-layer connecting rod.

[0016] Preferably, a thermocouple is arranged around the piezoelectric transducer, and the thermocouple is used to test the temperature around the piezoelectric transducer.

[0017] Based on the above-described semiconductor crystal material growth apparatus, the present invention also provides a semiconductor crystal material growth method, comprising the following steps:

[0018] ① Turn on the signal processing system;

[0019] ② Introduce gas into the growth furnace and reset the collected signals;

[0020] ③ Perform the crystal growth process;

[0021] ④ Detect the signal from the piezoelectric transducer to determine whether the growth process has been terminated.

[0022] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0023] The semiconductor crystal material growth apparatus and method of the present invention can detect cracks generated during or after crystal growth and during the cooling process. The apparatus can use a conventional high-temperature reactor for the HVPE method. The quartz tray of the conventional high-temperature reactor is connected to the bottom of the reactor via a double-layer connecting rod. The double-layer connecting rod contains a resonant cavity and a piezoelectric transducer, which can collect and amplify the acoustic wave signal of the crystal vibrating when cracks are generated during the growth or cooling process, and convert the collected signal into an electrical signal to detect whether cracks have been generated in the crystal. This apparatus and method can determine at which stage the crack is generated and improve the corresponding process, thereby reducing unnecessary waste of raw materials and time costs. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.

[0025] Appendix Figure 1 This is a schematic diagram of a semiconductor crystal material growth apparatus according to the present invention;

[0026] Appendix Figure 2 This is a schematic diagram of the double-layer connecting rod described in this invention;

[0027] Appendix Figure 3 for Figure 2 A sectional view of the double-layer connecting rod along the AA direction;

[0028] Appendix Figure 4 for Figure 2 A sectional view along line AA of another embodiment of the double-layer connecting rod;

[0029] Appendix Figure 5 This is a flowchart of a semiconductor crystal material growth method according to the present invention. Detailed Implementation

[0030] To make the technical problems solved by the present invention, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "straight," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "first position" and "second position" refer to two different positions.

[0032] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections or detachable connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0033] As attached Figure 1-4As shown, the semiconductor crystal material growth apparatus of the present invention includes a growth furnace body 1 and a signal processing system located outside the growth furnace body 1. The growth furnace body can be a furnace structure commonly used in the art, such as a high-temperature furnace body made of HVPE, which can withstand high temperature and high pressure to achieve crystal growth. It is equipped with matching air inlet pipes, air outlet pipes and temperature control system. The air inlet pipes, air outlet pipes and temperature control system can adopt the existing furnace structure without changing the air inlet pipes, air outlet pipes and temperature control system.

[0034] The growth furnace body 1 is provided with a tray 2 and a double-layer connecting rod 3 connected to the tray 2; the tray 2 and the double-layer connecting rod 3 can be made of the same material. In the art, quartz trays are usually used as the tray structure for crystal growth. When growing at high temperature (usually the growth temperature is around 1100℃), the coefficient of thermal expansion is small and there is no difference. Moreover, no impurities are generated at high temperature, which will not affect the growth of crystals, and will not affect the propagation of sound waves and vibrations.

[0035] As attached Figure 2-4 As shown, the double-layer connecting rod 3 includes an inner resonant thin-walled structure 5 and an outer resonant thin-walled structure 6, which are preferably made of quartz material. Both the inner resonant thin-walled structure 5 and the outer resonant thin-walled structure 6 have symmetrical cross-sections and can be circular or square, etc. The center line of the inner resonant thin-walled structure 5 and the center line of the outer resonant thin-walled structure 6 are on the same straight line. The outer diameter of the inner resonant thin-walled structure 5 is 28-35mm and the wall thickness is 0.5-0.8mm. The outer diameter of the outer resonant thin-walled structure 6 is 45-55mm and the wall thickness is 0.5-0.8mm.

[0036] The external resonant thin-walled structure 6 is connected and fixed to the internal resonant thin-walled structure 5 by multiple connecting pins 8. The multiple connecting pins 8 can be arranged in a multi-layer form, with four pins evenly arranged in each layer. The diameter of the connecting pins is 1-5mm.

[0037] The space between the outer resonant thin-walled structure 6 and the inner resonant thin-walled structure 5 forms an outer resonant cavity, and the inner space of the inner resonant thin-walled structure 5 forms an inner resonant cavity; a piezoelectric transducer 7 is provided in the inner resonant cavity, the piezoelectric transducer 7 is fixedly connected to the inner resonant thin-walled structure 5, and the piezoelectric transducer 7 is electrically connected to the signal processing system.

[0038] The connecting pins serve two purposes: firstly, they support the inner and outer resonant thin-walled structures 5 and 6 of the double-layer connecting rod; secondly, the vibration signal received in the outer resonant cavity is amplified by the connecting pins, and then transmitted to the inner resonant cavity. The inner resonant cavity, utilizing a dual-oscillator structure, forms a highly sensitive solid-state acoustic wave sensing structure capable of collecting and transmitting the transmitted sound waves and vibrations to the piezoelectric transducer 7. The double-layer connecting rod structure can have a circular or square cross-section, facilitating the symmetrical placement of the connecting pins to amplify the vibration sensing effect.

[0039] To improve the sensitivity of the signal collected by the piezoelectric transducer 7 and enhance the efficiency of sound acquisition, the piezoelectric transducer can be fixed at the center of the inner resonant cavity via a fixed shaft 9. Scattering plates 10 are located around the piezoelectric transducer at positions corresponding to the pins 8. The scattering plates 10 can adopt a cross structure to form a cross plate. The cross plate is made of bronze, which has good sound wave scattering performance. Due to the unique concave corner structure of the cross plate, it will produce a directional scattering effect on the sound waves in the cavity, thereby generating a standing wave effect of equal wavelength in the cavity. At the midpoint of the diagonal line connecting the cross plates in the cavity (i.e., the location of the piezoelectric transducer), a strong convergence of sound waves and a sharp amplification of sound pressure are formed, thereby driving the piezoelectric transducer to produce stronger vibrations and greater output.

[0040] The inner and outer layers of the double-layer linkage structure can amplify the vibration signal on the one hand, and also serve as heat insulation on the other. Since the crystal growth environment temperature inside the growth furnace 1 is high, the high temperature will affect the normal operation of the piezoelectric transducer inside. Therefore, a heat insulation structure 4 is also provided outside the double-layer linkage structure corresponding to the piezoelectric transducer. The heat insulation material of the heat insulation structure 4 is wrapped around the outside of the double-layer linkage structure. The heat insulation structure can include heat insulation cotton or a cooling structure. In this way, the position corresponding to the piezoelectric transducer 7 can be placed inside the high-temperature chamber of the growth furnace 1, so that it is closer to the tray and can receive the acoustic wave signal generated by the crystal crack more sensitively.

[0041] Furthermore, the upper end of the double-layer connecting rod 3 is connected to the tray 2, and the lower end of the double-layer connecting rod 3 extends to the outside of the growth furnace body 1. The signal processing system is located outside the growth furnace body 1, and the signal processing system is electrically connected to the piezoelectric transducer 7 through the lower end of the double-layer connecting rod 3.

[0042] The piezoelectric transducer 7 is made of piezoelectric material, and the generated electrical signal is transmitted to the signal processing system from the lower end of the double-layer connecting rod 3 via a wire. The selected piezoelectric material can be a polycrystalline piezoelectric ceramic, such as barium titanate piezoelectric ceramic, lead zirconate titanate piezoelectric ceramic, niobate piezoelectric ceramic, and lead magnesium niobate piezoelectric ceramic; polymer-piezoelectric ceramic composite materials can also be selected. These piezoelectric composite materials have good flexibility and can be used to make extremely thin components. The addition of piezoelectric ceramics can improve the shortcomings of polymer piezoelectric materials, such as small piezoelectric constant and high polarization electric field.

[0043] The piezoelectric transducer 7 has a double-layered connecting rod structure and a heat-insulating material layer on the outside. Since the operating temperature of the piezoelectric ceramic is related to its Curie temperature, the piezoelectric transducer cannot operate in the high-temperature furnace environment of crystal growth (around 1100℃). The Curie temperature of a piezoelectric ceramic refers to the phase transition temperature at which the piezoelectric material transforms from a ferroelectric phase to a paraelectric phase. For all piezoelectric products, the piezoelectric material has a critical temperature Tc, i.e., the Curie temperature. Below the critical temperature, the piezoelectric ceramic exhibits a ferroelectric phase, and at this point, the piezoelectric ceramic is in a polarized ordered state. Above the critical temperature Tc, the piezoelectric ceramic transforms from a ferroelectric phase to a paraelectric phase, at which point the internal electric dipole moment of the piezoelectric ceramic is disordered and in a polarized disordered state. Different piezoelectric products use different piezoelectric materials, and therefore have different Curie temperatures. The Curie temperature of piezoelectric materials is approximately between 350℃ and 430℃. The ferroelectric properties and performance of piezoelectric ceramics disappear when the material exceeds the Curie temperature. Therefore, it is crucial to use piezoelectric ceramics below the Curie temperature. By incorporating thermal insulation materials, the operating temperature of the piezoelectric transducer can be ensured to remain below 200°C, thus guaranteeing its stable operation within the transducer over extended periods.

[0044] In this crystal growth furnace system, during the crystal growth process or cooling process, the vibration or sound wave generated when the crystal cracks due to stress concentration is transmitted and amplified by the double-layer connecting rod and the connecting pins and cross plates inside the connecting rod. The amplified sound pressure is received by the piezoelectric transducer 7. The piezoelectric transducer 7 vibrates and deforms, and outputs an electrical signal under the piezoelectric effect, thereby realizing the sound-to-electric conversion. The generated electrical signal is exported and transmitted to the signal processing system.

[0045] The signal processing system includes an amplifier circuit, a gain control circuit, a filter circuit, a display screen, an alarm, etc. It can extract, amplify, control the gain, and filter the internal output electrical signals, and display them on the display screen. If a signal is detected, the alarm will sound and record the corresponding process time period. It can determine the time period when the crack occurred, stop the process, and then improve the subsequent process.

[0046] Thermocouples can also be installed around the piezoelectric transducer 7 in the inner resonant cavity. The thermocouples can test the temperature around the piezoelectric transducer. The temperature measured by the thermocouples can also be displayed on an external display screen to detect the temperature of the piezoelectric transducer's working environment. If the temperature measured by the thermocouple exceeds 250°C, the heat insulation structure should be improved or replaced to ensure the temperature of the piezoelectric transducer's working environment and to ensure the accuracy of the test.

[0047] When growing crystals using the aforementioned semiconductor crystal material growth apparatus, the crystal material can be group II or IV crystals such as gallium nitride and aluminum nitride, or silicon carbide crystals. (See reference...) Figure 5 The crystal growth process is as follows:

[0048] ① First, turn on the signal processing system and thermocouple connected to the piezoelectric transducer.

[0049] ②Then, the reaction gas is introduced through the air inlet pipe. The reaction gas can vary depending on the crystal being grown. During the gas introduction process, due to gas disturbances and acoustic vibrations from the external environment outside the chamber, the piezoelectric transducer may receive vibration signals and convert them into electrical signals. At this time, it is necessary to reset the signal output by the piezoelectric transducer to zero to prevent gas flow and external environmental vibrations from interfering with the output signal.

[0050] ③ Next, the crystal growth process is carried out. The gas flow and heating temperature conditions are maintained during crystal growth. During the growth process, the signal processing system detects the signal from the internal piezoelectric transducer. If an abnormal signal is detected, the growth process is terminated. A signal threshold can be preset in the signal processing system. When the electrical signal corresponding to the frequency and amplitude of the detected sound wave exceeds the threshold signal, an alarm is activated, the growth stage is stopped, and the current growth stage is recorded.

[0051] ④ If no alarm is triggered, the crystal growth process will continue until it is completed. If cracks occur during the cooling process, the subsequent cooling steps will be optimized and improved.

[0052] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. An apparatus for growing a semiconductor crystalline material, characterized by: The application relates to a signal processing system for a growth furnace, which comprises a growth furnace body (1) and a signal processing system outside the growth furnace body, wherein a tray (2) is arranged in the growth furnace body (1), and a double-layer connecting rod (3) is connected with the tray (2); the double-layer connecting rod (3) comprises an inner resonant thin-wall structure (5) and an outer resonant thin-wall structure (6), the outer resonant thin-wall structure (6) is connected and fixed with the inner resonant thin-wall structure (5) through a plurality of connecting pins (8), a space between the outer resonant thin-wall structure (6) and the inner resonant thin-wall structure (5) forms an outer resonant cavity, and an inner space of the inner resonant thin-wall structure (5) forms an inner resonant cavity; a piezoelectric transducer (7) is arranged in the inner resonant cavity, the piezoelectric transducer (7) is fixedly connected with the inner resonant thin-wall structure (5), and the piezoelectric transducer (7) is electrically connected with the signal processing system; the tray (2) is used for carrying a crystal, and the sound wave vibration generated by the crystal during the growth and / or cooling process is transmitted to the piezoelectric transducer (7) through the double-layer connecting rod (3), and the piezoelectric transducer (7) outputs an electric signal and feeds back to the signal processing system; the signal processing system detects the electric signal, and if there is signal abnormality, the growth stage is stopped and the growth stage at the moment is recorded.

2. A growth apparatus for semiconductor crystalline material as claimed in claim 1, wherein: The tray (2) and the double-layer connecting rod (3) are made of the same material.

3. A growth apparatus for semiconductor crystalline material as claimed in claim 2, wherein: The tray (2) and the double-layer connecting rod (3) are made of quartz.

4. The apparatus of claim 1, wherein: The outer diameter of the inner resonant thin-wall structure (5) is 28-35 mm, and the wall thickness is 0.5-0.8 mm; the outer diameter of the outer resonant thin-wall structure (6) is 45-55 mm, and the wall thickness is 0.5-0.8 mm; and the diameter of the connecting pin (8) is 1-5 mm.

5. The apparatus of claim 1, wherein: The inner resonant thin-wall structure (5) and the outer resonant thin-wall structure (6) are both structures with symmetrical cross sections, and the center line of the inner resonant thin-wall structure (5) is on the same line as the center line of the outer resonant thin-wall structure (6).

6. The apparatus of claim 1, wherein: The piezoelectric transducer (7) is located at the center position of the inner resonant cavity, and the piezoelectric transducer (7) is fixedly connected with the inner resonant thin-wall structure (5) through a fixing shaft (9); and the inner wall of the inner resonant thin-wall structure (5) is provided with a scattering plate (10) at the position corresponding to the connecting pin.

7. A growth apparatus for semiconductor crystalline material as claimed in claim 6, wherein: The scattering plate (10) is a cross structure and is made of bronze.

8. The apparatus of claim 1, wherein: The piezoelectric transducer (7) is arranged in the part of the double-layer connecting rod (3) located inside the growth furnace body (1), and the double-layer connecting rod (3) is provided with a heat insulation structure (4) outside the position where the piezoelectric transducer (7) is located; the upper end of the double-layer connecting rod (3) is connected with the tray (2), the lower end of the double-layer connecting rod (3) extends to the outside of the growth furnace body (1), and the signal processing system is electrically connected with the piezoelectric transducer (7) through the lower end of the double-layer connecting rod (3).

9. The apparatus of claim 1 or 8, wherein: A thermocouple is arranged around the piezoelectric transducer (7), and the thermocouple is used for testing the temperature around the piezoelectric transducer (7).

10. A method for growing a semiconductor crystal material using the apparatus for growing a semiconductor crystal material according to claim 1, characterized by, The application further discloses a method for using the signal processing system, which comprises the following steps: (1) first, the signal processing system connected with the piezoelectric transducer (7) and the thermocouple are started; (2) gas is introduced into the growth furnace body (1), and the collected signals are reset, so that the gas flow and the vibration of the external environment during the gas introduction process do not interfere with the output signals; ③ Crystal growth process is carried out; the crystal growth is carried out under the conditions of keeping the gas flowing and the temperature of heating, and in the growth process, the signal processing system detects the electric signal output by the internal piezoelectric transducer; if there is signal abnormality, the growth stage is stopped and the growth stage at this time is recorded; ④ The signal of the piezoelectric transducer (7) is detected to determine whether the growth process is terminated, if not, the crystal growth process is carried out until the growth process is ended.

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