A rotary batch epitaxial growth device and its preparation method

Abstract

The present invention discloses a rotary batch epitaxial growth device, comprising a wafer loading system, a front-end module of the device, a left wafer vacuum chamber, a right wafer vacuum chamber, a wafer transfer chamber, a plasma etching chamber, a heating volatilization chamber, a right reaction module, and a left reaction module. The wafer loading system is used to place wafer boxes, each of which is loaded with 25 wafers. The front-end module of the device is provided with a robot to take out the wafers from the wafer boxes on the wafer loading system, and after calibrating and positioning, transport them to the left wafer vacuum chamber and the right wafer vacuum chamber. The wafer transfer chamber is provided with a robot to grab the wafers in the wafer vacuum chamber. The robot loads a single wafer and transports it to a subsequent reaction chamber for first performing selective epitaxy and then performing full epitaxy. A. adhesion and cracking between the wafer boat and the wafer are avoided; b. the epitaxial temperature is reduced, the growth time is shortened, the boundary between the Si and SiGe layers is clear, and the electrical performance of the chip is improved.

Description

Technical Field

[0001] The present invention relates to a semiconductor epitaxial device, in particular to a rotary batch epitaxial device and a preparation method thereof. Background Art

[0002] Semiconductor epitaxial equipment mainly grows a new semiconductor crystal layer on the substrate material, which is called an epitaxial layer. The epitaxial process refers to growing a layer of single crystal material with the same lattice arrangement as the substrate on a single crystal substrate. The epitaxial layer can be a homogeneous epitaxial layer (Si / Si) or a heterogeneous epitaxial layer (SiGe / Si or SiC / Si, etc.). At present, mainstream semiconductor epitaxial equipment manufacturers use the technology of stacking epitaxial layers vertically and arranging and connecting them horizontally, but this technology is limited by the lateral space of the wafer. According to the growth method, the epitaxial process can be divided into two categories: full epitaxy (BlanketEpi) and selective epitaxy (SelectiveEpi). The temperature of the full epitaxial process is controlled between 300-600℃, and the growth rate is faster. During epitaxy, thin film deposition occurs inside the reaction chamber. The wafers in the reaction chamber are loaded onto a wafer boat. When the film deposition exceeds 1 to 3 μm, the film deposited at the contact point between the wafer boat and the wafer adheres, causing the following two situations to occur when the wafer is unloaded from the wafer boat: a. The film breaks at the adhesion point; b. When the wafer is unloaded, nanoparticles are generated, affecting the surface quality of the wafer in the reaction chamber and reducing the chip yield. Compared with the full epitaxy process, selective epitaxy can form an epitaxial layer only on the wafer surface. The process temperature is controlled between 600-800°C, and the growth rate is slower than that of full epitaxy. Etching gases such as HCl and Cl2 are introduced during the process. The selectivity of epitaxial growth is achieved by adjusting the relative rates of epitaxial growth and in-situ etching. When the selective epitaxy process generates Si and SiGe epitaxial stacks, due to the high process temperature, the Ge element in the SiGe layer generated after a period of reaction will diffuse into the adjacent Si layer, resulting in a blurred boundary between the Si and SiGe layers. In some applications, this will cause the electrical performance of the chip to degrade.

[0003] Chinese patent CN106663604B proposes a method and apparatus for batch processing substrates during epitaxial thin film formation, wherein the substrates are transported to a transfer chamber, and a robotic arm in the transfer chamber transfers the substrates to multiple pre-cleaning chambers. In the multiple pre-cleaning chambers, oxides (such as natural oxides) on the surfaces of the substrates can be removed in batches, thereby achieving uniform epitaxial deposition during batch processing of the substrates, thereby increasing substrate throughput. However, the above-mentioned technology cannot achieve the integration of selective epitaxy and full epitaxy technology. The present invention proposes a solution to the above problem as follows. Summary of the Invention

[0004] The purpose of the present invention is to provide a rotary batch epitaxial growth device and a preparation method thereof, which solves the problem that the existing wafer batch epitaxial growth device cannot realize the integration of selective epitaxy and full epitaxy technology.

[0005] The above technical objectives of the present invention are achieved through the following technical solutions:

[0006] A rotary batch epitaxial growth device includes a wafer loading system, a front-end module, a left wafer vacuum chamber, a right wafer vacuum chamber, a wafer transfer chamber, a plasma etching chamber, a heating volatilization chamber, a right reaction module, and a left reaction module. The wafer loading system is used to place wafer boxes, each of which is loaded with 25 wafers. The front-end module of the device has a robot that takes out the wafers from the wafer box on the wafer loading system, calibrates and positions them, and then carries them to the left wafer vacuum chamber and the right wafer vacuum chamber. The wafer transfer chamber has a robot that can grab the wafers in the wafer vacuum chamber. The robot loads a single wafer and transports it to the subsequent reaction chamber. The plasma etching chamber performs the first wafer pretreatment. The plasma in the chamber reacts with the oxide on the wafer surface and converts it into volatile substances. The heating volatilization chamber performs the second wafer pretreatment. By increasing the chamber temperature, the volatile substances converted in the plasma etching chamber can be heated and sublimated. The internal structures of the right reaction module and the left reaction module are symmetrical to each other, and both can perform full epitaxial and selective epitaxial processes. The circuits and gas path modules of the two reaction modules are independent of each other, and the epitaxial process can be performed simultaneously.

[0007] Preferably, the wafer left vacuum chamber and the wafer right vacuum chamber are transition chambers to achieve switching between atmospheric environment and vacuum environment.

[0008] Preferably, the right reaction module and the left reaction module both include a vacuum loading chamber, an air path control unit, a wafer transfer valve, a circuit control unit, a crystal boat transmission mechanism, a heater, a reaction chamber door, a crystal boat, and a reaction chamber. The wafers that have completed pretreatment in the vacuum loading chamber are loaded onto the crystal boat in sequence. The crystal boat transmission mechanism can realize the lifting and rotating functions of the crystal boat, so that the crystal boat loaded with wafers enters the reaction chamber for epitaxial process, and the crystal boat can load 50-80 wafers at a time.

[0009] Preferably, the heater is installed outside the reaction chamber to change the temperature conditions of epitaxial growth.

[0010] Preferably, the reaction chamber door is used to seal the reaction chamber when the wafer boat is in the vacuum loading chamber to load wafers, thereby avoiding temperature loss in the reaction chamber.

[0011] Preferably, the wafer transfer valve is installed in the vacuum loading chamber, and the robot in the wafer transfer chamber transfers the wafer into the vacuum loading chamber through the wafer transfer valve.

[0012] Preferably, the circuit control unit provides electrical control for the epitaxial reaction process, and the gas circuit control unit provides pneumatic control for the epitaxial reaction process.

[0013] A method for preparing a rotary batch epitaxial growth device, applied to the above-mentioned epitaxial growth device, comprises the following steps:

[0014] Step 1: The wafer box is transported to the wafer box loading platform. The atmospheric manipulator in the front-end module of the equipment moves the wafers in the wafer box to the front-end module of the equipment for calibration and positioning, and then moves them to the wafer vacuum chamber. The wafer vacuum chamber is now converted from an atmospheric environment to a vacuum environment. After it is completely converted to a vacuum environment, the manipulator in the wafer transfer chamber grabs the single wafer in the wafer vacuum chamber and sends it into the plasma etching chamber for the first surface pretreatment to convert the oxide on the wafer surface into a volatile solid substance. After the reaction is completed, the manipulator in the wafer transfer chamber takes the wafer out of the plasma etching chamber and places it in the heated volatilization chamber to heat and sublimate the volatile substances on the wafer surface. The wafer surface pretreatment is completed when the reaction is completed.

[0015] Step 2: The robot in the wafer transfer chamber places the pre-treated wafers into the reaction module for selective epitaxial growth. The robot loads the pre-treated wafers onto the wafer boat in sequence. During the process of loading the wafers, the wafer boat descends from its original position to the lowest position. During this process, the wafer boat automatically adjusts its height to accommodate each wafer. After loading, the wafer boat conveying mechanism rotates from its initial position to the working position. At this time, the reaction chamber door is opened, and the wafer boat conveying mechanism loads the wafer boat and continues to rise, and the reaction chamber is sealed, and the temperature and process gas are adjusted to perform the selective epitaxial growth process.

[0016] Step 3. After completing the selective epitaxial process, the wafer boat in the right reaction module returns to the vacuum loading chamber, and the robot in the wafer transfer chamber transfers all the wafers in the right reaction module to the left reaction module for a full epitaxial process. After the process is completed, the wafers are transported back to the wafer box of the front-end module of the equipment, and the empty wafer boat continues to be transported back to the reaction chamber by the wafer boat transfer mechanism, and clean gas is introduced to complete the cleaning of the reaction chamber and the wafer boat, thus completing an epitaxial process.

[0017] Beneficial effects:

[0018] The present invention adopts a combination of selective epitaxy and full epitaxy, first performing selective epitaxy and then full epitaxy, which a. avoids adhesion and cracking between the wafer boat and the wafer, and b. reduces the epitaxial temperature and growth time, making the boundary between the Si and SiGe layers clear and improving the electrical performance of the chip; adopts a multi-wafer batch reaction method, and 50-80 wafers can be loaded on the wafer boat into the reaction chamber, which greatly improves the reaction efficiency. Single-wafer reaction equipment usually only grows on the front side of the wafer. When the film thickness of the epitaxially generated is thick, the wafer will undergo stress deformation, which seriously affects the yield. Therefore, single-wafer equipment is usually unable to generate thicker films. The present invention adopts furnace tube reaction equipment to carry out epitaxial growth on both the front and back sides of the wafer. When a thicker film is generated on the wafer surface, no large stress deformation will occur; the plasma in the plasma oxide removal chamber reacts with the oxide on the wafer surface to generate volatile solid substances attached to the wafer surface; the heated volatilization chamber heats and sublimates the volatile solid substances attached to the wafer surface to obtain a clean wafer surface, thereby effectively improving the quality of epitaxial film growth. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A top view of a rotary batch epitaxial growth device;

[0020] Figure 2 This is a diagram showing the external structure of a reaction module in a rotary batch epitaxial growth device;

[0021] Figure 3 This is a diagram of the internal structure of a reaction module in a rotary batch epitaxial growth device;

[0022] Figure 4 A diagram showing the combined structure of a wafer boat transport mechanism and a wafer boat in a rotary batch epitaxial growth device;

[0023] Figure 5 A side cross-sectional view of wafer transfer mode a in a rotary batch epitaxial growth apparatus;

[0024] Figure 6 is a side cross-sectional view of a wafer transfer mode b in a rotary batch epitaxial growth apparatus;

[0025] Figure 7 A top view of wafer transfer mode a in a rotating batch epitaxial growth device;

[0026] Figure 8 A top view of wafer transfer mode b in a rotating batch epitaxial growth device.

[0027] Reference numerals:

[0028] 101. Wafer loading system; 102. Equipment front-end module; 103a. Wafer left vacuum chamber; 103b. Wafer right vacuum chamber; 104. Wafer transfer chamber; 105. Plasma etching chamber; 106. Heating and volatilization chamber; 200. Reaction module; 200a. Right reaction module; 200b. Left reaction module; 201. Vacuum loading chamber; 202. Gas path control unit; 203. Wafer transfer valve; 204. Circuit control unit; 205. Wafer boat transmission mechanism; 206. Heater; 207. Reaction chamber door; 208. Wafer boat; 209. Reaction chamber. DETAILED DESCRIPTION

[0029] The following description is merely a preferred embodiment of the present invention, and the scope of protection is not limited to this embodiment. All technical solutions based on the principles of the present invention should be within the scope of protection of the present invention. It should also be noted that improvements and modifications that do not depart from the principles of the present invention, which are within the scope of protection of the present invention, are within the scope of protection of the present invention.

[0030] like Figure 1-8 As shown, a rotary batch epitaxial growth device includes a wafer loading system 101, a front-end module 102, a left wafer vacuum chamber 103a, a right wafer vacuum chamber 103b, a wafer transfer chamber 104, a plasma etching chamber 105, a heating volatilization chamber 106, a right reaction module 200a, and a left reaction module 200b. The wafer loading system 101 is used to place wafer boxes, each of which is loaded with 25 wafers. The front-end module 102 has a robot to take out the wafers from the wafer box on the wafer loading system 101, and after calibration and positioning, carry them to the left wafer vacuum chamber 103a and the right wafer vacuum chamber 103b. The wafer transfer chamber 104 has a The robot arm can grab the wafer in the wafer vacuum chamber 103, load the single wafer by the robot arm, and transport it to the subsequent reaction chamber. The wafer is pretreated for the first time in the plasma etching chamber 105. The plasma in the chamber reacts with the oxide on the surface of the wafer and converts it into volatile substances. The wafer is pretreated for the second time in the heating volatilization chamber 106. The chamber temperature is increased, and the volatile substances converted in the plasma etching chamber 105 can be heated and sublimated. The internal structures of the right reaction module 200a and the left reaction module 200b are symmetrical to each other, and both can perform full epitaxial and selective epitaxial processes. The circuit and gas path modules of the two reaction modules are independent of each other, and the epitaxial process can be performed simultaneously.

[0031] Specifically, the epitaxial process is not limited to performing the selective epitaxial process and the full epitaxial process in two reaction modules respectively. When the reaction module is under maintenance or there are other process requirements, the selective epitaxial process and the full epitaxial process can also be completed sequentially in a single reaction module. The process flow and process method are the same as those of performing the selective epitaxial process and the full epitaxial process in two reaction modules.

[0032] The selective epitaxial growth process is as follows: the pre-treated wafer is transferred to the reaction module 200a for the selective epitaxial growth process. The selective epitaxial growth process temperature is controlled at 600-800°C. First, the Si layer is epitaxially grown on the wafer surface. During epitaxial growth of the Si layer, the reaction chamber pressure is typically controlled between 50 and 200 Torr, and the required process gases are introduced: ① 100 to 10,000 sccm of process gas is introduced, where SiH4, SiH2Cl2, and DCS are generally selected as any one or a mixture of several gases, which can be selected according to process requirements; ② Etching gases such as Cl2, HCl, and HBr are simultaneously introduced during the epitaxial process. The flow rate of the etching gas is typically controlled between 10 and 5,000 sccm. The etching gas can achieve in-situ etching. By controlling the gas flow rate, the relative rates of epitaxial growth and in-situ etching can be adjusted to achieve Si epitaxial growth only on the wafer surface; ③ 0.1 to 20 L / min of H2 gas is also required during the epitaxial process. H2 acts as a protective gas to prevent the formation of oxidizing substances or oxygen-containing groups during the reaction. After a period of reaction, a Si layer with a thickness of 1 to 100 nm is finally generated. Then, epitaxial growth of the SiGe layer is carried out. During the epitaxial growth of the SiGe layer, the pressure of the reaction chamber is usually controlled between 10 and 200 Torr, and the gases required for the process are introduced: ① 100 to 10,000 sccm of process gas is introduced, wherein the process gas includes SiH4 (or SiH2Cl2 or DCS or any mixture of the three gases) and GeH4. The ratio of the gas flow rates of GeH4 and SiH4 (or SiH2Cl2 or DCS or any mixture of the three gases) can be adjusted according to the chip performance parameters, and the ratio is usually controlled between 0.05 and 0.8; ② Cl2 and H2O are introduced simultaneously during the epitaxial process. Etching gases such as Cl and HBr are used. The flow rate of the etching gas is usually controlled between 10-500 sccm. The etching gas can achieve in-situ etching. By controlling the gas flow rate, the relative rates of epitaxial growth and in-situ etching can be adjusted to achieve SiGe epitaxial growth only on the wafer surface. ③ 0.1L-20L / min of H2 gas is introduced to avoid the possible appearance of oxidizing substances or oxygen-containing groups during the reaction process. After a period of reaction, a SiGe layer with a thickness of 1-100nm is finally generated. After a period of alternating growth of the Si layer and the SiGe layer, the selective epitaxial process is terminated.

[0033] The full epitaxial growth process is as follows: After the reaction chamber 209 in the reaction module 200b is self-cleaned, the full epitaxial growth process temperature is adjusted to between 300°C and 600°C. The wafer that has completed the selective epitaxial growth process will be transferred to the reaction module 200b for the full epitaxial growth process. First, the Si layer is epitaxially grown on the wafer surface. During the epitaxial growth of the Si layer, the pressure in the reaction chamber is usually controlled between 50 and 200 Torr, and the required process gases are introduced: ① 100 to 10,000 sccm of process gas, where SiH4 (or SiH2Cl2 or DCS) is generally used; ② 0.1L to 20L / min of H2 gas is introduced to avoid the possible generation of oxidizing substances or oxygen-containing groups during the reaction process. After a period of reaction, a Si layer with a thickness of 1 to 100nm is finally generated. Then, the SiGe layer is epitaxially grown. During the epitaxial growth of the SiGe layer, the pressure of the reaction chamber 209 is usually controlled between 50 and 200 Torr, and the gases required for the process are introduced: ① 100 to 2000 cc of process gas is introduced, wherein the process gas includes SiH4 (or SiH2Cl2 or DCS or any mixture of the three gases) and GeH4, GeH4 and SiH4 (or SiH2Cl2 or DCS or any mixture of the three gases). The ratio of the gas introduction amount can be adjusted according to the chip performance parameters, and the ratio is usually controlled between 0.05 and 0.8; ② 0.1L to 20L / min of H2 gas is introduced to avoid the generation of oxidizing substances or oxygen-containing groups during the reaction process. After a period of reaction, a SiGe layer with a thickness of 1 to 100nm is finally generated. After a period of alternating growth of the Si layer and the SiGe layer, the full epitaxial process is terminated, and an epitaxial layer is finally generated on the wafer. After the epitaxial process is completed, the thickness of the epitaxial layer can reach 1 to 8μm. The wafer exits the reaction chamber 209, the wafer boat 208 returns, the chamber door is closed, and the reaction chamber 209 begins self-cleaning. After the cleaning is completed, it is put into use in the next process.

[0034] The self-cleaning process of the reaction module 200b is as follows: Before the full epitaxial process, the reaction chamber 209 in the reaction module 200b is self-cleaned. This step actually occurs simultaneously with the previous selective epitaxial process. In the reaction module 200b, the pressure in the reaction chamber 209 is adjusted to 1-200 Torr, and the gases required for pre-cleaning are introduced: ① 100-10,000 sccm of etching gases such as HCl, Cl2, and HBr are introduced; ② H2 or N2 gases are introduced simultaneously to avoid the formation of oxidizing substances or oxygen-containing groups that may appear during the reaction process;

[0035] It is worth noting that the plasma etching chamber 105 and the heating volatilization chamber 106 can also be combined into one chamber, and heating volatilization can be directly performed in the same chamber after the plasma etching is completed.

[0036] Furthermore, the wafer left vacuum chamber 103a and the wafer right vacuum chamber 103b are transition chambers to achieve switching between atmospheric environment and vacuum environment;

[0037] Specifically, during semiconductor manufacturing, different process steps may require different environmental conditions. For example, some steps may need to be performed at atmospheric pressure, while others may need to be performed in a vacuum environment to reduce contamination or promote specific chemical reactions. The design of the transition chamber allows for smooth transitions between these different environments, ensuring continuity and efficiency in the wafer processing process.

[0038] Furthermore, the right reaction module 200a and the left reaction module 200b each include a vacuum load chamber 201, a gas circuit control unit 202, a wafer transfer valve 203, a circuit control unit 204, a wafer boat transfer mechanism 205, a heater 206, a reaction chamber door 207, a wafer boat 208, and a reaction chamber 209. Pre-processed wafers are sequentially loaded onto the wafer boat 208 in the vacuum load chamber 201. The wafer boat transfer mechanism 205 is capable of lifting and rotating the wafer boat 208 so that the wafer boat 208 loaded with wafers enters the reaction chamber 209 for epitaxial growth. The wafer boat 208 can load 50-80 wafers at a time.

[0039] Specifically, the steps of the epitaxial preparation method are as follows:

[0040] Step 1: The wafer first enters the plasma etching chamber 105, and gases such as NF3, NH3, and H2 are introduced into the chamber and plasma is excited by inductive coupling, so that the oxides on the wafer surface react chemically with the plasma and are converted into volatile solid substances;

[0041] Step 2: After the wafer has fully reacted, it is transferred from the plasma etching chamber 105 to the heating volatilization chamber 106 for heating, so that the volatile solid matter on the wafer surface is sublimated by heating, and a second surface treatment is performed to obtain an ultra-clean silicon wafer surface.

[0042] Furthermore, the heater 206 is installed outside the reaction chamber 209 to change the temperature conditions of epitaxial growth;

[0043] Specifically, by installing the heater 206 outside the reaction chamber, the temperature inside the reaction chamber 209 can be controlled more accurately because the heater 206 can be adjusted independently of other variables in the reaction process. The external heater 206 can be designed to uniformly heat the entire reaction chamber 209 to ensure uniform growth of the epitaxial layer on the wafer, which is crucial for improving the performance and reliability of the device. Installing the heater 206 outside the reaction chamber 209 can simplify the maintenance and cleaning of the equipment because the heater 206 is more accessible and less susceptible to contaminants generated during the reaction process.

[0044] Furthermore, the reaction chamber door 207 is used to seal the reaction chamber 209 when the wafer boat 208 is in the vacuum loading chamber 201 to load wafers, thereby preventing temperature loss in the reaction chamber 209.

[0045] Specifically, the reaction chamber door 207 is closed when the wafer boat 208 is loaded with wafers, ensuring the sealing of the reaction chamber 209 to prevent external gas from entering or internal gas from leaking. By sealing the reaction chamber, heat loss can be reduced and the required high temperature environment in the reaction chamber 209 can be maintained, because temperature fluctuations may affect the growth quality and uniformity of the crystal. The reaction chamber door 207 also helps to control the gas environment in the reaction chamber. For example, when conducting certain chemical reactions, it is necessary to control the inflow and outflow of specific gases to ensure the efficiency of the reaction and the quality of the product. During the wafer loading process, the sealing effect of the reaction chamber door 207 also helps to protect operators from the influence of high temperature and harmful gases, thereby improving the safety of operation.

[0046] Furthermore, the wafer transfer valve 203 is installed in the vacuum loading chamber 201, and the robot in the wafer transfer chamber 104 transfers the wafer into the vacuum loading chamber 201 through the wafer transfer valve 203;

[0047] Specifically, the wafer transfer valve 203 allows for precise control of the wafer transfer process, ensuring stability and safety during transfer to the vacuum load chamber 201. The wafer transfer valve 203 works in conjunction with the robot in the wafer transfer chamber 104 to achieve precise wafer transfer. This coordinated operation ensures seamless transfer of wafers between different process steps.

[0048] Furthermore, the circuit control unit 204 provides electrical control for the epitaxial reaction process, and the gas circuit control unit 202 provides pneumatic control for the epitaxial reaction process;

[0049] Specifically, the circuit control unit 204 and the gas circuit control unit 202 are monitored and adjusted by a central control system. This system can be computerized and can automatically adjust the settings of the control units according to preset process parameters. This automated control method helps to reduce human errors and improve production efficiency and product quality.

[0050] Working principle: The preparation method of the above-mentioned rotary batch epitaxial device includes the following steps:

[0051] Step 1: The wafer box is transported to the wafer box loading platform 101. The atmospheric manipulator in the equipment front-end module 102 moves the wafers in the wafer box to the equipment front-end module 102 for calibration and positioning, and then moves them to the wafer vacuum chamber 103. The wafer vacuum chamber 103 is now converted from an atmospheric environment to a vacuum environment. After the vacuum environment is completely converted, the manipulator in the wafer transfer chamber 104 grabs the single wafer in the wafer vacuum chamber 103 and sends it to the plasma etching chamber 105 for the first surface pretreatment to convert the oxide on the wafer surface into a volatile solid substance. After the reaction is completed, the manipulator in the wafer transfer chamber 104 takes the wafer out of the plasma etching chamber 105 and puts it into the heating volatilization chamber 106 to heat and sublimate the volatile substances on the wafer surface. When the reaction is completed, the wafer surface pretreatment is completed.

[0052] Step 2: The robot in the wafer transfer chamber 104 places the pre-treated wafers into the reaction module 200a for selective epitaxial growth. The robot loads the pre-treated wafers onto the wafer boat 208 in sequence. During the process of loading the wafers, the wafer boat 208 descends from the original position 208a to the position 208b. During this process, the wafer boat 208 automatically adjusts its height to accommodate each wafer. After loading, the wafer boat conveying mechanism 205 rotates from the initial position 205a to the working position 205b. At this time, the reaction chamber door 207 is opened, and the wafer boat conveying mechanism 205 loads the wafer boat 208 and continues to rise, and realizes the sealing of the reaction chamber 209, adjusts the temperature and process gas, and performs the selective epitaxial growth process.

[0053] Step 3: After completing the selective epitaxial process, the wafer boat 208 in the reaction module 200a is returned to the vacuum loading chamber 201, and the robot in the wafer transfer chamber 104 transfers all the wafers in the reaction module 200a to the reaction module 200b for a full epitaxial process. After the process is completed, the wafers are transported back to the wafer box of the equipment front-end module 102, and the empty wafer boat 208 continues to be transported back to the reaction chamber 209 by the wafer boat transfer mechanism 205, and the clean gas is introduced to complete the cleaning of the reaction chamber 209 and the wafer boat 208, thereby completing one epitaxial process.

Claims

1. A method for preparing a rotary batch epitaxial growth device, characterized in that: The device comprises a wafer loading system, a front-end module, a left wafer vacuum chamber, a right wafer vacuum chamber, a wafer transfer chamber, a plasma etching chamber, a heating volatilization chamber, a right reaction module, and a left reaction module. The wafer loading system is provided with a wafer box for placing wafers. The preparation method comprises the following steps: Step 1: The wafer box is transported to the wafer box loading platform. The atmospheric manipulator in the front-end module of the equipment moves the wafers in the wafer box to the front-end module of the equipment for calibration and positioning, and then moves them to the wafer vacuum chamber. The wafer vacuum chamber is now converted from an atmospheric environment to a vacuum environment. After it is completely converted to a vacuum environment, the manipulator in the wafer transfer chamber grabs the single wafer in the wafer vacuum chamber and sends it into the plasma etching chamber for the first surface pretreatment to convert the oxide on the wafer surface into a volatile solid substance. After the reaction is completed, the manipulator in the wafer transfer chamber takes the wafer out of the plasma etching chamber and places it in the heated volatilization chamber to heat and sublimate the volatile substances on the wafer surface. The wafer surface pretreatment is completed when the reaction is completed. Step 2: The robot in the wafer transfer chamber places the pre-treated wafer into the reaction module for selective epitaxial growth. The robot loads the pre-treated wafers onto the wafer boat in sequence. During the process of loading the wafers, the wafer boat descends from its original position to the lowest position. During this process, the wafer boat automatically adjusts its height to accommodate each wafer loaded. After loading is completed, the wafer boat conveyor mechanism rotates from its initial position to its working position. At this time, the reaction chamber door is opened, and the wafer boat conveyor mechanism continuously rises with the wafer boat loaded, and the reaction chamber is sealed. The temperature and process gas are adjusted to perform selective epitaxial growth. The selective epitaxial growth process is as follows: the pre-treated wafer is transferred to the reaction module, the temperature is controlled at 600-800°C, the epitaxial growth of the Si layer is first performed on the wafer surface, and then the epitaxial growth of the SiGe layer is performed. The alternating growth of the Si layer and the SiGe layer is cyclically performed to terminate the selective epitaxial growth process. Step 3. After completing the selective epitaxial process, the wafer boat in the right reaction module returns to the vacuum loading chamber, and the robot in the wafer transfer chamber transfers all the wafers in the right reaction module to the left reaction module for the full epitaxial process. After the process is completed, the wafers are transported back to the wafer box of the front-end module of the equipment, and the empty wafer boat continues to be transported back to the reaction chamber by the wafer boat transmission mechanism. Clean gas is introduced to complete the cleaning of the reaction chamber and the wafer boat, thus completing an epitaxial process. The full epitaxial process process is as follows: After the self-cleaning of the reaction chamber in the reaction module is completed, the full epitaxial process temperature is adjusted. The temperature is controlled between 300~600℃. The wafers that have completed the selective epitaxial process will be transferred to the reaction module for the full epitaxial process. First, the Si layer will be epitaxially grown on the wafer surface, and then the SiGe layer will be epitaxially grown. The alternating growth of the Si layer and the SiGe layer will be cyclically repeated to end the full epitaxial process. Finally, an epitaxial layer is generated on the wafer. After the epitaxial process is completed, the thickness of the epitaxial layer reaches 1~8μm. The wafer exits the reaction chamber, the wafer boat returns, the chamber door is closed, and self-cleaning begins in the reaction chamber. After cleaning is completed, it is put into use in the next process.

2. The method for preparing a rotary batch epitaxial device according to claim 1, wherein: The wafer left vacuum chamber and the wafer right vacuum chamber are transition chambers to achieve switching between atmospheric environment and vacuum environment.

3. The method for preparing a rotary batch epitaxial device according to claim 2, wherein: The right reaction module and the left reaction module both include a vacuum loading chamber, an air path control unit, a wafer transfer valve, a circuit control unit, a wafer boat transmission mechanism, a heater, a reaction chamber door, a wafer boat, and a reaction chamber. The wafers that have completed pretreatment in the vacuum loading chamber are loaded onto the wafer boat in sequence. The wafer boat transmission mechanism can realize the lifting and rotating functions of the wafer boat, so that the wafer boat loaded with wafers enters the reaction chamber for epitaxial process, and the wafer boat can load 50-80 wafers each time.

4. The method for preparing a rotary batch epitaxial device according to claim 3, wherein: The heater is installed outside the reaction chamber to change the temperature conditions of epitaxial growth.

5. The method for preparing a rotary batch epitaxial device according to claim 3, wherein: The reaction chamber door is used to seal the reaction chamber when the wafer boat is in the vacuum loading chamber to load wafers, thereby preventing temperature loss in the reaction chamber.

6. The method for preparing a rotary batch epitaxial device according to claim 3, characterized in that: The wafer transfer valve is installed in the vacuum loading chamber, and the robot in the wafer transfer chamber transfers the wafer into the vacuum loading chamber through the wafer transfer valve.

7. The method for preparing a rotary batch epitaxial device according to claim 3, wherein: The circuit control unit provides electrical control for the epitaxial reaction process, and the gas circuit control unit provides pneumatic control for the epitaxial reaction process.

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