CN114855279A - Silicon carbide epitaxial growth pipeline system - Google Patents

Abstract

The invention discloses a silicon carbide epitaxial growth pipeline system, which comprises a liquid storage device, an input unit and an output unit, wherein the liquid storage device comprises a constant temperature mechanism and a liquid tank arranged in the constant temperature mechanism; the output unit comprises an output main pipeline and a plurality of output branch pipelines connected in parallel with the output main pipeline, one end of the output main pipeline is hermetically connected to the liquid tank and provided with a pressure controller, and at least one part of the output branch pipelines are provided with second flow controllers which are used for controlling the flow of the output branch pipelines. The invention can realize the independent control of the flow of each output branch pipeline and the adjustable proportion of the dosage distribution of each output branch pipeline, is particularly suitable for large-size (8-12 inches) epitaxial furnace chambers, and improves the concentration uniformity, the thickness uniformity and the like in the preparation of large-size epitaxial wafers.

Description

Silicon carbide epitaxial growth pipeline system

Technical Field

The invention relates to the field of third-generation semiconductor silicon carbide material epitaxial equipment, in particular to a silicon carbide epitaxial growth pipeline system capable of realizing multi-channel independent control.

Background

The third generation semiconductor silicon carbide epitaxial growth generally uses a Chemical Vapor Deposition (CVD) method, in which Trichlorosilane (TCS) is responsible for providing silicon elements required for epitaxial growth, and Trimethylaluminum (TMA) is responsible for providing aluminum elements required for P-type doping in epitaxial growth. Trichlorosilane (TCS) and Trimethylaluminum (TMA) are both in a liquid state at normal temperature, and in a normal state, TCS and TMA cannot be directly introduced into a furnace chamber for use as liquid phase sources.

Because TCS is an important growth source of silicon carbide epitaxy, the dosage of TCS directly determines C, Si which is an important influence factor of epitaxial debugging, and TMA is an important doping source of silicon carbide epitaxy, and the dosage of TMA directly determines the doping concentration of P-type epitaxy, so that the linear controllability of the dosages of TCS and TMA is important to ensure.

Referring to fig. 1, a conventional piping system simultaneously communicates a plurality of pipes such as a main pipe, a bypass pipe, etc. of a reaction chamber through an output pipe, and ensures a constant temperature of a liquid tank inside the system through a thermostatic mechanism, and controls a pressure in the liquid tank through a pressure controller (EPC). When the pipeline system is used for supplying the TCS, the density rho of the TCS dissolved in the carrier gas H2 is constant when the TCS liquid in the liquid tank is maintained in a constant temperature and pressure state, so that after the flow rate v of the carrier gas H2 is calculated by the flow controller MFC, the total dose of the TCS actually introduced into the reaction cavity can be calculated by the mass formula m-rho.v. When the piping system is used to provide TMA, the same principles apply as for TCS.

The existing pipeline system and the dosage control mode thereof can only control the total dosage of TCS or TMA actually introduced into the reaction chamber, and cannot realize the independent control of multiple TCS sources or TMA sources respectively, so that the pipeline system and the dosage control mode thereof are enough in the control application of a small-size (4-6 inches) epitaxial furnace chamber. However, with the continuous expansion of the epitaxial dimension, for example, in a pipeline system for a large-sized (8-12 inches) epitaxial furnace chamber, it is necessary to implement independent control of multiple TCS sources or TMA sources, respectively, so as to implement independent control of multiple C, Si, Al, etc., otherwise, neither the concentration uniformity nor the thickness uniformity of the large-sized epitaxial wafer can meet the requirements.

Therefore, there is a need to provide a pipeline system capable of realizing independent control of multiple pipelines and adjusting the dosage distribution ratio of each pipeline, so as to solve the above problems.

Disclosure of Invention

The invention aims to provide a silicon carbide epitaxial growth pipeline system which can realize independent control of multiple pipelines and can adjust the dosage distribution proportion of each pipeline.

In order to achieve the purpose, the technical scheme of the invention is as follows: the silicon carbide epitaxial growth pipeline system comprises a liquid storage device, an input unit and an output unit; the liquid storage device comprises a constant temperature mechanism and a liquid tank arranged in the constant temperature mechanism, and the constant temperature mechanism is used for keeping the temperature of the liquid tank constant; the input unit comprises an input pipeline, one end of the input pipeline is hermetically connected with the liquid tank, the other end of the input pipeline is used for connecting a carrier gas source, and a first flow controller is arranged on the input pipeline and used for controlling the flow of the input pipeline; the output unit comprises an output main pipeline and a plurality of output branch pipelines, one end of the output main pipeline is hermetically connected to the liquid tank, the other end of the output main pipeline is connected with the plurality of output branch pipelines in parallel, a pressure controller is arranged on the output main pipeline and used for keeping the pressure of the liquid tank constant, and a second flow controller is arranged on at least one part of the output branch pipelines and used for controlling the flow of the output branch pipelines where the second flow controller is arranged.

Preferably, the output branch pipeline includes a first output branch pipeline and at least one second output branch pipeline, each second output branch pipeline is provided with the second flow controller, the second flow controller is used for controlling the flow rate of the second output branch pipeline, and the flow rate distribution proportion of the first output branch pipeline and each second output branch pipeline is adjusted by calculating the flow rate of the first output branch pipeline, or calculating the proportion of the sum of the flow rates of the second output branch pipelines in the total flow rate of the output main pipeline, or directly controlling the flow rate of the first output branch pipeline.

Preferably, a first flow detector is disposed on the main output pipeline, and the first flow detector is configured to detect a total flow of the main output pipeline, and calculate a ratio of a sum of flows of the second output branch pipelines to the total flow of the main output pipeline by using a ratio of a flow of the second flow controller to a flow of the first flow detector, or calculate a flow of the first output branch pipeline by using a difference between the flow of the first flow detector and the flow of the second flow controller.

Preferably, the first output branch pipeline is provided with a flow detection and control unit, and the flow detection and control unit detects and directly controls the flow of the first output branch pipeline.

Preferably, the flow detecting and controlling unit is the second flow controller, and the flow of the first output branch pipeline is controlled by the second flow controller; or the flow detection and control unit comprises a second flow detector and a resistance regulator, the flow of the first output branch pipeline is regulated by regulating the resistance of the resistance regulator, and the flow of the first output branch pipeline is detected by the second flow detector.

Preferably, the resistance regulator is a needle valve, and the second flow detector is a flow meter.

Preferably, a pressure sensor is further disposed on the output main pipeline, and the pressure sensor is configured to detect a pressure between the output main pipeline and the first output branch pipeline and between the output main pipeline and the second output branch pipeline.

Preferably, the output unit further includes an evacuation pipeline, the evacuation pipeline and the output branch pipeline are connected in parallel to the output main pipeline, a burst valve is disposed on the evacuation pipeline, and when the pressure between the output main pipeline and the output branch pipeline is greater than a threshold of the burst valve, the burst valve is damaged and is depressurized through the evacuation pipeline.

Preferably, the silicon carbide epitaxial growth pipeline system further comprises a controller, the controller is respectively electrically connected to the pressure controller, the first flow controller, the second flow controller and the first flow detector, the controller is used for acquiring the flow of the first flow controller, the second flow controller and the first flow detector, and is used for calculating the total dosage of the liquid phase source according to the flow rate of the first flow controller and the dissolved density of the liquid phase source in the liquid tank in the carrier gas, and is also used for calculating the ratio of the sum of the flow rates of the second output branch pipelines in the total flow rate of the output main pipeline according to the flow rate of each second flow controller and the flow rate of the first flow detector, or calculating the difference between the total flow of the output main pipeline and the flow of each second flow controller.

Preferably, the first flow controller and the second flow controller are both mass flow meters, and the first flow detector is a flow meter.

Compared with the prior art, the silicon carbide epitaxial growth pipeline system comprises a liquid storage device, a liquid storage device and a control device, wherein the liquid storage device comprises a constant temperature mechanism and a liquid tank arranged in the constant temperature mechanism, an output pipeline comprises an output main pipeline and a plurality of output branch pipelines, the output main pipeline is provided with a pressure controller, the temperature of the liquid tank is kept constant through the constant temperature mechanism, and the pressure of the liquid tank is kept constant through the pressure controller, so that the liquid tank can be kept under constant temperature and constant pressure all the time, and the dissolving density of a liquid phase source in the liquid tank in carrier gas is constant; secondly, a first flow controller is arranged on an input pipeline, so that the total output dosage of the liquid phase source can be calculated according to the flow of the first flow controller and the dissolved density of the liquid phase source in the liquid tank in the carrier gas; furthermore, at least one part of the output branch pipelines is provided with a second flow controller, and the second flow controller is used for controlling the flow of the output branch pipeline where the second flow controller is located, so that the flow of each output branch pipeline can be independently controlled by adjusting the proportion of the flow of the second flow controller in the total flow of the output main pipeline or adjusting the difference value between the flow of the second flow controller and the total flow of the output main pipeline, and the flow distribution proportion of each output branch pipeline can be adjusted. Therefore, the silicon carbide epitaxial growth pipeline system is particularly suitable for large-size (8-12 inches) epitaxial furnace chambers so as to improve the concentration uniformity, the thickness uniformity and the like in the preparation of large-size epitaxial wafers.

Drawings

Fig. 1 is a schematic diagram of a piping system in the prior art.

Fig. 2 is a schematic structural view of a silicon carbide epitaxial growth pipe system in a first embodiment of the present invention.

FIG. 3 is a schematic structural view of a silicon carbide epitaxial growth pipe system according to a second embodiment of the present invention.

FIG. 4 is a schematic structural view of a silicon carbide epitaxial growth pipe system according to a third embodiment of the present invention.

FIG. 5 is a schematic structural view of a pipeline system for epitaxial growth of silicon carbide according to a fourth embodiment of the present invention.

FIG. 6 is a schematic structural view of a pipeline system for epitaxial growth of silicon carbide according to a fifth embodiment of the present invention.

Detailed Description

Embodiments of the present invention will now be described with reference to the drawings, wherein like element numerals represent like elements. It should be noted that the orientation descriptions of the present invention, such as the directions or positional relationships indicated above, below, left, right, front, rear, etc., are all based on the directions or positional relationships shown in the drawings, and are only for convenience of describing the technical solutions of the present application or simplifying the description, but do not indicate or imply that the devices or elements referred to must have specific orientations, be constructed in specific orientations, and operate, and therefore, should not be construed as limiting the present application. The description of first, second, etc. merely serves to distinguish technical features and should not be interpreted as indicating or implying a relative importance or implying a number of indicated technical features or implying a precedence relationship between indicated technical features.

Referring to fig. 2-6, the silicon carbide epitaxial growth pipeline system 1 provided by the present invention is mainly suitable for large-sized (8-12 inches) epitaxial furnace chambers, and is configured to provide a liquid phase source to the reaction chamber 2 of the epitaxial furnace chamber, for example, to provide a Trichlorosilane (TCS) liquid phase source to the reaction chamber 2, so as to implement separate regional C \ Si control in the reaction chamber 2, or to provide a Trimethylaluminum (TMA) liquid phase source to the reaction chamber 2, so as to implement linear adjustability between the TMA dopant amount and the P-type carrier concentration. Understandably, it is not limited to providing a liquid phase source of TCS or TMA, but can of course be used to provide other types of liquid phase sources to the reaction chamber 2; and the device is not limited to be used in an epitaxial furnace chamber with a large size (8-12 inches), and is also applicable to other occasions needing to realize multi-pipeline independent control.

With continued reference to fig. 2-6, the silicon carbide epitaxial growth pipeline system 1 provided by the present invention includes a liquid storage device 100, an input unit 200, and an output unit 300. The liquid storage device 100 includes a constant temperature mechanism 110 and a liquid tank 120 disposed in the constant temperature mechanism 110, and the constant temperature mechanism 110 is configured to keep a temperature of the liquid tank 120 constant. The input unit 200 comprises an input pipeline 210, one end of the input pipeline 210 is hermetically connected to the tank 120, the input pipeline 210 extends into the bottom of the tank 120, the other end of the input pipeline 210 is used for connecting the carrier gas source 3, a first flow controller MFC1 is arranged on the input pipeline 210, and a first flow controller MFC1 is used for controlling the flow of the input pipeline 210. The output unit 300 includes an output main pipeline 310 and a plurality of output branch pipelines 320, one end of the output main pipeline 310 is hermetically connected to the tank 120, and the output main pipeline 310 extends into the top of the tank 120, the other end of the output main pipeline 310 is connected in parallel with the plurality of output branch pipelines 320, and the other ends of the plurality of output branch pipelines 320 are used for connecting to a user device; the output main line 310 is provided with a pressure controller EPC for keeping the pressure of the liquid tank 120 constant; at least a part of the output branch line 320 is provided with a second flow controller MFC2, and the second flow controller MFC2 is used for controlling the flow of the output branch line 320. In the present invention, the total dosage of the outputted liquid phase source can be calculated according to the flow rate of the first flow controller MFC1 and the density of the liquid phase source in the liquid tank 120 dissolved in the carrier gas; meanwhile, by controlling and adjusting the ratio of the flow of the second flow controller MFC2 in the total flow of the main output pipeline 310 or controlling and adjusting the difference between the flow of the second flow controller MFC2 and the total flow of the main output pipeline 310, it is possible to independently control the flow of each of the output branch pipelines 320 and to adjust the dose distribution ratio of each of the output branch pipelines 320.

In the present invention, the ratio of the flow rate of the second flow controller MFC2 to the total flow rate of the output main line 310, or the difference between the flow rate of the second flow controller MFC2 and the total flow rate of the output main line 310 may be calculated and adjusted by a field worker, or may be automatically calculated by a control system.

In a preferred embodiment of the present invention, the silicon carbide epitaxial growth pipeline system 1 further includes a controller, which is electrically connected to the pressure controller EPC, the first flow controller MFC1, and the second flow controller MFC2, respectively, and is configured to obtain the flow rates of the first flow controller MFC1 and the second flow controller MFC2, calculate the total dosage of the liquid phase source according to the flow rate of the first flow controller MFC1 and the dissolved density ρ of the liquid phase source in the carrier gas in the liquid tank 120, and calculate the ratio of the total flow rate of the output main pipeline 310 or calculate the difference between the total flow rate of the output main pipeline 310 and the flow rate of each second flow controller MFC2, so as to realize automatic control of the flow rate of each output branch pipeline 320, improve the automation degree and the control precision of the silicon carbide epitaxial growth pipeline system 1, so as to improve the concentration uniformity, the thickness uniformity and the like in the preparation of large-size epitaxial wafers.

Referring now to FIGS. 2-6, respectively, various embodiments of the SiC epitaxial growth pipe system 1 of the present invention will be described in detail.

Referring to fig. 2, in the first embodiment of the present invention, the liquid storage device 100 and the input unit 200 are arranged as described above, and therefore, the description is not repeated.

In this embodiment, the output unit 300 comprises an output main pipeline 310 and a plurality of output branch pipelines 320, one end of the output main pipeline 310 is hermetically connected to the tank 120, and the end of the output main pipeline 310 is located at the top of the tank 120, so that the steam in the tank 120 can be output through the output main pipeline 310; the other end of the main output pipeline 310 is connected in parallel with a plurality of branch output pipelines 320, and the branch output pipelines 320 are respectively used for connecting to a user device. The output main line 310 is provided with a pressure controller EPC for keeping the pressure in the tank 120 constant.

More specifically, the output branch pipe 320 includes a first output branch pipe 321 and a plurality of second output branch pipes 322, and the first output branch pipe 321 and the second output branch pipe 322 can be connected to different pipes of the user equipment respectively. The first output branch pipe 321 and the second output branch pipe 322 are respectively provided with a second flow controller MFC2, and the second flow controller MFC2 is used for controlling the flow of the first output branch pipe 321 and the second output branch pipe 322.

With continued reference to FIG. 2, in one embodiment, the outlet branch 320 includes a first outlet branch 321 and a second outlet branch 322, the first outlet branch 321 is connected to the main path of the reaction chamber 2, and the second outlet branch 322 is connected to the bypass of the reaction chamber 2. Therefore, the liquid phase source provided in the liquid tank 120 is introduced into the main path and the bypass path of the reaction chamber 2, respectively. Understandably, the number of the output branch pipes 320 is not limited to the embodiment illustrated in fig. 2, and of course, more output branch pipes 320 may be provided to connect more pipes of the reaction chamber 2 or to connect more pipes of other using devices.

In this embodiment, the first flow controller MFC1 and the second flow controller MFC2 are mass flow meters, but the present invention is not limited to this, and it is needless to say that other flow rate detecting devices may be selected to realize the flow rate control of each output branch line.

Referring to fig. 2 again, in the present embodiment, since the temperature of the liquid tank 120 is kept constant by the constant temperature mechanism 110 of the liquid storage apparatus 100, and the pressure of the liquid tank 120 is kept constant by the pressure controller EPC on the output main pipeline 310, under the condition of constant temperature and constant pressure, the density ρ of the liquid phase source in the liquid tank 120 dissolved in the carrier gas is constant, and the total dose of the liquid phase source actually flowing into the reaction chamber 2 can be calculated according to the mass formula m ═ ρ · v; meanwhile, the flow rates of the first output branch pipe 321 and the second output branch pipe 322 can be directly controlled by the second flow controllers MFC2, so that the flow rates of the first output branch pipe 321 and the second output branch pipe 322 can be independently controlled, and the purpose of adjusting the flow rate distribution ratio of the first output branch pipe 321 and the second output branch pipe 322 can be directly achieved by adjusting the second flow controllers MFCs 2.

In the setting manner of this embodiment, due to factory errors or precision differences of the first flow controller MFC1 and the second flow controller MFC2, in an actual use process, pressure imbalance occurs between the first output branch pipe 321 and the second output branch pipe 322 due to the slight differences, and when the pressure imbalance is accumulated to a certain extent and cannot be adjusted or decompressed, the first output branch pipe 321, the second output branch pipe 322, and the second flow controller MFC2 disposed thereon may be damaged, so that the entire silicon carbide epitaxial growth pipeline system 1 has a potential safety hazard. To solve this possible problem, the present invention further provides other more preferred embodiments, as described in detail below.

Referring to fig. 3, in a second embodiment of the present invention, the silicon carbide epitaxial growth pipeline system 1 includes a liquid storage device 100, an input unit 200, and an output unit 300. The liquid storage device 100 includes a constant temperature mechanism 110 and a liquid tank 120 disposed in the constant temperature mechanism 110, and the constant temperature mechanism 110 is configured to keep a temperature of the liquid tank 120 constant. The input unit 200 comprises an input pipeline 210, one end of the input pipeline 210 extends into the bottom of the tank 120, the input pipeline 210 is connected with the tank 120 in a sealing way, the other end of the input pipeline 210 is connected with the carrier gas source 3, the input pipeline 210 is provided with a first flow controller MFC1, and the first flow controller MFC1 is used for controlling the flow of the input pipeline 210. The output unit 300 includes an output main pipeline 310 and a plurality of output branch pipelines 320 connected in parallel to the output main pipeline 310, the output main pipeline 310 extends into the top of the liquid tank 120, the output main pipeline 310 is hermetically connected to the liquid tank 120, and each output branch pipeline 320 is respectively connected to different pipelines of the reaction chamber 2.

With continued reference to fig. 3, in the present embodiment, the output main pipe 310 is sequentially provided with a pressure controller EPC and a pressure sensor PT, the pressure controller EPC is used for keeping the pressure of the liquid tank 120 constant, and the pressure sensor PT is used for detecting the pressure between the output main pipe 310 and each output branch pipe 320, so as to ensure that the pressure controller EPC does not fail in the operating state.

More specifically, the outlet branch pipe 320 includes a first outlet branch pipe 321 and at least a second outlet branch pipe 322, the first outlet branch pipe 321 is connected to the main path of the reaction chamber 2, and the second outlet branch pipe 322 is connected to the bypass of the reaction chamber 2, of course, both of them can be connected to other pipes of the reaction chamber 2 or to different pipes of other using devices. In this embodiment, the flow rates of the first output branch pipeline 321 and the second output branch pipeline 322 can be independently controlled and the flow rate distribution ratio between the first output branch pipeline 321 and the second output branch pipeline 322 can be adjusted by calculating the flow rate of the first output branch pipeline 321, calculating the ratio of the sum of the flow rates of the second output branch pipelines 322 to the total flow rate of the output main pipeline 310, or directly controlling the flow rate of the first output branch pipeline 321, because the second flow controller MFC2 is disposed on the second output branch pipeline 322, and controlling the flow rate of the second output branch pipeline 322 through the second flow controller MFC 2.

With continued reference to FIG. 3, in the present embodiment, the output branch pipe 320 includes a first output branch pipe 321 and a second output branch pipe 322, the first output branch pipe 321 is connected to the main path of the reaction chamber 2, and the second output branch pipe 322 is connected to the bypass of the reaction chamber 2. The main output pipe 310 is provided with a first flow rate detector FM1, the first flow rate detector FM1 is used to detect the total flow rate flowing through the main output pipe 310, in other words, the first flow rate detector FM1 has only a flow rate detection function, and does not control the total flow rate of the main output pipe 310; and a second flow controller MFC2 is disposed on the second output branch pipe 322, and the second flow controller MFC2 is used for controlling the flow of the second output branch pipe 322, that is, the second flow controller MFC2 can be directly adjusted as required to make the flow of the second output branch pipe 322 meet the requirement.

In this embodiment, the ratio of the flow rate of the second output branch line 322 to the total flow rate of the output main line 310 can be calculated from the total flow rate of the output main line 310 and the flow rate of the second output branch line 322, and the flow rate of the first output branch line 321 can be calculated from the difference between the total flow rate of the output main line 310 and the flow rate of the second output branch line 322, so that the flow rates of the first output branch line 321 and the second output branch line 322 can be independently controlled and the flow rate distribution ratio of both can be adjusted by adjusting the second flow rate controller MFC 2.

Referring now to fig. 4, in a third embodiment of the present invention, the difference from the second embodiment shown in fig. 3 is mainly that: instead of providing the first flow rate detector FM1 on the main output line 310, the first output branch line 321 is directly provided with a flow rate detection and control unit that detects and directly controls the flow rate of the first output branch line 321.

More specifically, the flow rate detecting and controlling unit includes a resistance regulator 3211 and a second flow rate detector FM2, wherein the second flow rate detector FM2 is used to detect the flow rate of the first output branch pipe 321, that is, the second flow rate detector FM2 only has a detecting function and does not have a flow rate controlling function, therefore, in this embodiment, the resistance regulator 3211 is added to regulate the flow rate of the first output branch pipe 321 by regulating the resistance of the resistance regulator 3211, so that the flow rate of the first output branch pipe 321 can be directly controlled, that is, the flow rate of the first output branch pipe 321 can be directly regulated and known by regulating the resistance regulator 3211 and detecting the second flow rate detector FM2, and the flow rate of the second output branch pipe 322 can be controlled by the second flow rate controller MFC2, which can also realize independent control of the flow rates of the first output branch pipe 321 and the second output branch pipe 322, and the flow distribution ratio of the two can be adjusted.

In the present embodiment, the resistance regulator 3211 is preferably a needle valve, so the flow rate of the first output branch pipe 321 is regulated by regulating the resistance of the needle valve, and it is understood that the flow rate of the first output branch pipe 321 is not limited to being controlled by the combination of the needle valve and the second flow rate detector FM2, and for example, a flow rate controller MFC or other flow rate control device may be directly provided on the first output branch pipe 321 for the purpose of flow rate detection and control.

Referring now to fig. 5, in a fourth embodiment of the present invention, the differences from the second embodiment shown in fig. 3 and the third embodiment shown in fig. 4 are mainly: the main output pipe 310 is provided with a first flow rate detector FM1, and the first output branch pipe 321 is provided with a second flow rate detector FM2 and a resistance regulator 3211.

The silicon carbide epitaxial growth pipeline system 1 in this embodiment can control the flow rate in the following ways: (1) calculating the ratio of the flow rate of the second output branch pipeline 322 in the total flow rate of the output main pipeline 310 according to the total flow rate of the output main pipeline 310 detected by the first flow rate detector FM1 and the flow rate of the second output branch pipeline 322 controlled by the second flow rate detector FM2, and achieving the purpose of respectively controlling the flow rates of the first output branch pipeline 321 and the second output branch pipeline 322 and the flow rate distribution ratio between the two by adjusting the ratio; (2) according to the total flow of the main output pipeline 310 detected by the first flow detector FM1 and the flow of the second output branch pipeline 322 controlled by the second flow detector FM2, the difference between the total flow of the main output pipeline 310 and the flow of the second output branch pipeline 322 is calculated, so as to obtain the flow of the first output branch pipeline 321, and then the flow of the first output branch pipeline 321 and the flow of the second output branch pipeline 322 can be respectively and independently controlled and the flow distribution proportion between the first output branch pipeline 321 and the second output branch pipeline 322 can be adjusted by adjusting the second flow controller MFC 2; (3) the flow rate of the second output branch line 322 is controlled by the second flow controller MFC2, and the flow rate of the first output branch line 321 can be directly obtained by the adjustment of the resistance regulator 3211 and the detection of the second flow rate detector FM2, so that the flow rates of the first output branch line 321 and the second output branch line 322 can be independently controlled and the flow rate distribution ratio between the first output branch line 321 and the second output branch line 322 can be adjusted by adjusting the second flow controller MFC 2.

In this embodiment, if the above-mentioned mode (1) or (2) is selected to implement flow control, at this time, the flow rate of the first output branch pipe 321 can be detected by the second flow rate detector FM2 to implement flow rate monitoring of the branch pipe, and an operator can quickly and intuitively know the flow rate of the first output branch pipe 321 through the reading of the second flow rate detector FM 2.

In the embodiments shown in fig. 3 to 5, the first flow controller MFC1 and the second flow controller MFC2 are preferably mass flow meters, and the first flow detector FM1 and the second flow detector FM2 are preferably flow meters. Of course, the above-mentioned devices are not limited, and other flow rate detecting and/or controlling devices may be flexibly selected according to the requirements.

With continued reference to fig. 3-5, in the second to fourth embodiments, the output unit 300 further includes an evacuation pipeline 330, and the evacuation pipeline 330 is connected to the main output pipeline 310 in parallel with the first branch output pipeline 321 and the second branch output pipeline 322.

More specifically, a burst valve 331 is disposed on the evacuation line 330, and in use, when the pressure between the main output line 310 and the first and second output branch lines 321, 322 is greater than a threshold of the burst valve 331, the burst valve 331 is broken and is depressurized through the evacuation line 330, thereby ensuring the safety of the entire system.

With continued reference to fig. 5, in one embodiment, the flow of second output branch pipe 322 is preferentially satisfied to control the flow of first output branch pipe 321 and realize the flow distribution between first output branch pipe 321 and second output branch pipe 322. More specifically, since the second flow controller MFC2 is used for realizing flow control, it has a certain resistance to the gas flowing through itself, and the second flow detector FM2 is used only for detecting the flow, and therefore, it has no resistance to the gas flowing through itself, so in order to prevent all the gas from flowing into the reaction chamber 2 through the second flow detector FM2 and further losing the regulation and control ability for the main and bypass, the present embodiment adds a needle valve at the front end of the second flow detector FM2 to increase the resistance to the gas flow flowing through the second flow detector FM2, and the resistance of the needle valve is adjusted to make the flow satisfy the second flow controller MFC2 preferentially.

During the specific adjustment, the needle valve is adjusted to reduce its diameter so as to increase the resistance of the gas flowing through the needle valve, so that the gas flowing through the second flow detector FM2 is hindered to a certain extent, at which time the gas will preferentially pass through the second flow controller MFC2 with smaller resistance, but since the second flow controller MFC2 is a flow control device, when the gas flowing through the second flow controller MFC2 reaches the set value, the excess gas will only flow into the reaction chamber 2 from the second flow detector FM2 or into the evacuation pipe via the burst valve 331. Thus, during adjustment, the needle valve cannot be adjusted so tightly that the resistance to gas flow through the second flow controller MFC2 is greater than the tolerance pressure of the burst valve 331, and so loosely that all of the gas flows into the reaction chamber 2 via the second flow controller MFC2, which would cause the second flow controller MFC2 to fail.

In one embodiment, the resistance of the needle valve is adjusted to make the resistance of the gas flowing through the second flow detector FM2 slightly larger than that of the second flow controller MFC2, so that the gas flowing through the second flow controller MFC2 quickly reaches a saturated state, that is, the flow rate of the second output branch pipe 322 reaches a set value, thereby realizing the flow rate control of the bypass, and then the remaining gas is introduced into the first output branch pipe 321 through the second flow detector FM2 and further into the main pipe, thereby realizing the independent control of the flow rates of the first output branch pipe 321 and the second output branch pipe 322.

In addition, when the resistance of the needle valve is too large, the gas cannot be introduced into the main path through the first output branch pipe 321, and therefore, a pressure build-up occurs, that is, a pipe pressure between the pressure controller EPC and the second flow rate detector FM2 and the second flow rate controller MFC2 becomes too high, and the pressure controller EPC fails. In the embodiment shown in fig. 3-5, the line pressure between the pressure controller EPC and the second flow rate detector FM2 and the second flow rate controller MFC2 is detected by the pressure sensor PT on the output main line 310, and when the line pressure between the pressure controller EPC and the second flow rate detector FM2 and the second flow rate controller MFC2 increases, the resistance of the needle valve can be readjusted according to the detection result of the pressure sensor PT, thereby ensuring that the pressure controller EPC does not fail due to over-adjustment of the needle valve in an operating state.

Furthermore, if the line pressure between the pressure controller EPC and the second flow rate detector FM2 and the second flow rate controller MFC2 increases to an uncontrollable level due to over-tight adjustment of the needle valve or other reasons, that is, if the line pressure is greater than the threshold value of the burst valve 331, the line pressure will damage the burst valve 331 and release the pressure to the evacuation line 330, so that the burst valve 331 serves as an emergency safety valve to ensure the safety of the line.

Referring again to fig. 3-5, in a preferred embodiment of the present invention, the silicon carbide epitaxial growth pipeline system 1 further includes a controller electrically connected to the pressure controller EPC, the first flow controller MFC1, the second flow controller MFC2, the first flow detector FM1, and the second flow detector FM2, respectively. Therefore, the controller can obtain the flow rate of the first flow controller MFC1, and then calculate the total dose of the liquid phase source actually flowing into the reaction chamber 2 according to the flow rate of the first flow controller MFC1 and the dissolved density ρ of the liquid phase source in the carrier gas under the conditions of constant temperature and constant pressure and the mass formula m ═ ρ · v. In addition, the controller may further obtain the total flow rate of the main output pipe 310 detected by the first flow rate detector FM1 and the flow rate of the second output branch pipes 322 controlled by the second flow rate controller MFC2, and then, according to a specifically set control method, calculate a ratio of the sum of the flow rates of the second output branch pipes 322 to the total flow rate of the main output pipe 310, or calculate a difference between the flow rate of the second output branch pipes 322 and the total flow rate of the main output pipe 310, to obtain the flow rate of the first output branch pipe 321. Furthermore, the controller can also obtain the flow rate of the first output branch pipe 321 detected by the second flow rate detector FM2 to directly control the flow rate of the first output branch pipe 321. Through the setting of the controller, the silicon carbide epitaxial growth pipeline system 1 can realize higher automation, and the accurate control of the flow rates of the first output branch pipeline 321 and the second output branch pipeline 322 can be realized.

Referring now to fig. 6, in a fifth embodiment of the present invention, the difference from the fourth embodiment shown in fig. 5 is mainly: the output branch pipes 320 include a first output main pipe 310 and a plurality of second output branch pipes 322, and the first output main pipe 310 and the plurality of second output branch pipes 322 are respectively connected to different pipes of a user equipment, so as to realize multi-pipe supply of the liquid phase source. Here, the first output main pipeline 310 and each second output branch pipeline 322 are arranged in the same manner as in the fourth embodiment shown in fig. 5, and therefore, the description thereof will not be repeated.

Referring again to fig. 5, the operation of the silicon carbide epitaxial growth pipe system 1 shown in fig. 5 for supplying a TCS liquid phase source to the reaction chamber 2 will be described in detail.

As shown in fig. 5, the TCS liquid phase source is contained in the tank 120, the carrier gas source 3 connected to the input pipeline 210 is hydrogen H2, the first output branch pipeline 321 is connected to the main path of the reaction chamber 2, and the second output branch pipeline 322 is connected to the bypass of the reaction chamber 2. Also, the temperature of the liquid tank 120 is ensured to be constant by the thermostatic mechanism 110, and the pressure in the liquid tank 120 is controlled to be constant by the pressure controller EPC.

Before the operation, the resistance of the first output branch pipe 321, that is, the resistance of the needle valve provided thereon, is adjusted according to the set value of the second flow controller MFC2, so that the resistance of the needle valve is slightly larger than the resistance of the second flow controller MFC2, and therefore, the gas preferentially flows through the second flow controller MFC2, and after the gas flowing through the second flow controller MFC2 is saturated, the remaining gas is introduced into the first output branch pipe 321 and further into the main pipe via the second flow detector FM2, and therefore, the flow rates of the first output branch pipe 321 and the second output branch pipe 322 can be independently controlled according to different set values of the second flow controller MFC 2.

Normally, the pressure at one end of the reaction chamber 2 is negative, and the pressure in the liquid tank 120 at the front end of the pressure controller EPC is positive, so that the carrier gas H2 flows to one end of the reaction chamber 2 through the liquid tank 120. In the process, the carrier gas H2 is introduced into the TCS liquid source at constant temperature and pressure through the input pipeline 210, so the carrier gas H2 carries the TCS vapor in a saturated state, that is, the saturated TCS vapor is introduced into the main pipeline through the first output branch pipeline 321, the saturated TCS vapor is introduced into the bypass pipeline through the second output branch pipeline 322, and the TCS is carried into the reaction chamber 2 in the form of saturated vapor for epitaxial growth.

In the above process, the density ρ of TCS dissolved in the carrier gas H2 is constant under constant temperature and pressure, and the flow v of the carrier gas H2 can be controlled and detected by the first flow controller MFC1, and then the total dose of TCS actually introduced into the reaction chamber 2 can be calculated according to the mass formula m ═ ρ · v.

At the same time, since the second flow controller MFC2 controls the flow rate of the second output branch pipe 322, the flow rate of the first output branch pipe 321 is calculated and controlled by controlling the ratio of the flow rate of the second flow controller MFC2 to the total flow rate of the first flow rate detector FM1 or by directly using the difference between the total flow rate of the first flow rate detector FM1 and the flow rate of the second flow controller MFC2, thereby achieving the flow rate control and the flow rate distribution ratio adjustment of the first output branch pipe 321 and the second output branch pipe 322, that is, the flow rates of the main pipe and the bypass of the reaction chamber 2 are independently controlled and the flow rate distribution ratio adjustment is achieved.

In the above process, if the pressure sensor PT detects that the line pressure between the pressure controller EPC and the second flow rate detector FM2 and the second flow rate controller MFC2 is too high, the flow rate distribution between the first output branch line 321 and the second output branch line 322 is adjusted by readjusting the resistance of the needle valve, and the line pressure is adjusted to ensure that the pressure controller EPC does not fail due to the line pressure in the operating state. If the line pressure between the pressure controller EPC and the second flow rate detector FM2, the second flow rate controller MFC2 increases to be uncontrollable, the line pressure will break the burst valve 331, and further release the pressure through the evacuation line 330, so that the burst valve 331 is used as an emergency safety valve to ensure the safety of the line.

Understandably, when the silicon carbide epitaxial growth pipeline system 1 of the present invention is used for providing a TMA liquid source to the reaction chamber 2, the TMA liquid source is contained in the liquid tank 120, the carrier gas source 3 connected to the input pipeline 210 of the liquid tank 120 is also hydrogen H2, and the concrete control manner of the silicon carbide epitaxial growth pipeline system 1 is the same as that for providing the TCS liquid source, and therefore, the description is not repeated.

In summary, in the silicon carbide epitaxial growth pipeline system 1 of the present invention, first, the liquid storage device 100 includes the constant temperature mechanism 110 and the liquid tank 120 disposed in the constant temperature mechanism 110, the output pipeline includes the output main pipeline 310 and the plurality of output branch pipelines 320, the output main pipeline 310 is provided with the pressure controller EPC, the temperature of the liquid tank 120 is kept constant by the constant temperature mechanism 110, and the pressure of the liquid tank 120 is kept constant by the pressure controller EPC, so that the liquid tank 120 can be kept at constant temperature and constant pressure all the time, and the density ρ of the liquid phase source in the liquid tank 120 dissolved in the carrier gas is constant; secondly, the input pipeline 210 is provided with a first flow controller MFC1, so that the total output dosage of the liquid phase source can be calculated according to the flow of the first flow controller MFC1 and the dissolved density ρ of the liquid phase source in the liquid tank 120 in the carrier gas; furthermore, since the second flow controller MFC2 is provided in at least a part of the output branch lines 320, and the second flow controller MFC2 is used to control the flow rate of the output branch line 320 in which it is provided, it is possible to achieve independent control of the flow rate of each output branch line 320 and to achieve an adjustable flow rate distribution ratio of each output branch line 320 by adjusting the proportion of the flow rate of the second flow controller MFC2 to the total flow rate of the output main line 310 or adjusting the difference between the flow rate of the second flow controller MFC2 and the total flow rate of the output main line 310. Therefore, the silicon carbide epitaxial growth pipeline system 1 of the invention is particularly suitable for large-size (8-12 inches) epitaxial furnace chambers so as to improve the concentration uniformity, the thickness uniformity and the like of large-size epitaxial wafers in the preparation process of the large-size epitaxial wafers.

The structure and arrangement of the reaction chamber 2 and its main and bypass paths, etc. related to the present invention are conventional structures well known to those skilled in the art, and will not be described in detail herein.

The above disclosure is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the scope of the present invention, therefore, the present invention is not limited by the appended claims.

Claims (10)

1. A silicon carbide epitaxial growth tube system, comprising:

the liquid storage device comprises a constant temperature mechanism and a liquid tank arranged in the constant temperature mechanism, and the constant temperature mechanism is used for keeping the temperature of the liquid tank constant;

the input unit comprises an input pipeline, two ends of the input pipeline are respectively connected with the carrier gas source and the liquid tank in a sealing mode, a first flow controller is arranged on the input pipeline, and the first flow controller is used for controlling the flow of the input pipeline;

the output unit comprises an output main pipeline and a plurality of output branch pipelines, one end of the output main pipeline is hermetically connected to the liquid tank, the other end of the output main pipeline is connected with the plurality of output branch pipelines in parallel, a pressure controller is arranged on the output main pipeline and used for keeping the pressure of the liquid tank constant, and at least one part of the output branch pipelines is provided with a second flow controller which is used for controlling the flow of the output branch pipelines where the second flow controller is arranged.

2. The silicon carbide epitaxial growth pipe system according to claim 1, wherein the output branch pipes include a first output branch pipe and at least one second output branch pipe, each of the second output branch pipes is provided with the second flow controller, and the second flow controller is configured to control the flow rate of the second output branch pipe, and the flow rate distribution ratio of the first output branch pipe to each of the second output branch pipes is adjusted by calculating the flow rate of the first output branch pipe, or calculating the ratio of the sum of the flow rates of the second output branch pipes to the total flow rate of the output main pipe, or directly controlling the flow rate of the first output branch pipe.

3. The silicon carbide epitaxial growth tube system according to claim 2, wherein a first flow rate detector is provided on the main output tube, the first flow rate detector is configured to detect a total flow rate of the main output tube, a ratio of a sum of flow rates of the second output branch tubes to the total flow rate of the main output tube is calculated by a ratio of a flow rate of the second flow rate controller to a flow rate of the first flow rate detector, or a flow rate of the first output branch tube is calculated by a difference between a flow rate of the first flow rate detector and a flow rate of the second flow rate controller.

4. The silicon carbide epitaxial growth pipeline system according to claim 2 or 3, wherein a flow rate detection and control unit is provided on the first output branch pipeline, and the flow rate of the first output branch pipeline is detected and directly controlled by the flow rate detection and control unit.

5. The silicon carbide epitaxial growth tube system of claim 4, wherein the flow detection and control unit is the second flow controller, the flow of the first output branch tube being controlled by the second flow controller; or

The flow rate detection and control unit comprises a second flow rate detector and a resistance regulator, the flow rate of the first output branch pipeline is regulated by regulating the resistance of the resistance regulator, and the flow rate of the first output branch pipeline is detected by the second flow rate detector.

6. The silicon carbide epitaxial growth tube system of claim 5, wherein the resistance regulator is a needle valve and the second flow detector is a flow meter.

7. The silicon carbide epitaxial growth tube system according to claim 2 or 3, wherein a pressure sensor is further provided on the output main tube for detecting a pressure between the output main tube and the first and second output branch tubes.

8. The silicon carbide epitaxial growth tube system of any one of claims 1-3, wherein the output unit further comprises an evacuation line connected in parallel to the output main line and having a burst valve disposed thereon, wherein the burst valve is broken to release pressure through the evacuation line when the pressure between the output main line and the output branch line is greater than a threshold value of the burst valve.

9. The silicon carbide epitaxial growth tube system of claim 3, further comprising a controller, the controller is respectively and electrically connected with the pressure controller, the first flow controller, the second flow controller and the first flow detector, the controller is used for acquiring the flow of the first flow controller, the second flow controller and the first flow detector, and is used for calculating the total dosage of the liquid phase source according to the flow rate of the first flow controller and the dissolved density of the liquid phase source in the liquid tank in the carrier gas, and is also used for calculating the ratio of the sum of the flow rates of the second output branch pipelines in the total flow rate of the output main pipeline according to the flow rate of each second flow controller and the flow rate of the first flow detector, or calculating the difference between the total flow of the output main pipeline and the flow of each second flow controller.

10. The silicon carbide epitaxial growth tube system of claim 3, wherein the first flow controller and the second flow controller are both mass flow meters and the first flow detector is a flow meter.

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