Multi-layer epitaxial growth apparatus and method thereof

Abstract

The invention provides multi-layer epitaxial growth equipment and a multi-layer epitaxial growth method. The equipment comprises a growth chamber, a plurality of preset pipelines and a control unit, wherein each preset pipeline comprises an epitaxial gas source and a valve group; the epitaxial gas source forms epitaxial gas; the valve group comprises a first valve and a second valve, the epitaxial gas source is connected with the exhaust port through the first valve, and the epitaxial gas source is connected with the growth chamber through the second valve; the growth chamber comprises a plurality of gas inlets and a plurality of gas outlets opposite to the gas inlets, the gas inlets are respectively connected with different preset pipelines, and epitaxial gas is introduced into the growth chamber to implement epitaxial growth; the control unit is connected with a plurality of preset pipelines and controls each preset pipeline to independently select one of the growth state, the preparation state and the standby state. According to the technical scheme, airflow in the next stage is prepared in parallel, so that the airflow stabilization time during air path switching in a traditional process is eliminated, and the overall growth cycle is shortened.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor manufacturing, and in particular to a multi-layer epitaxial growth device and a method thereof. Background Art

[0002] As semiconductor devices advance toward higher integration and higher performance, the demand for producing multilayer epitaxial layers is increasing. Traditional epitaxial growth processes require a gas flow stabilization process after switching between epitaxial layers of varying thickness, resistivity, or doping type, resulting in long process cycles and low efficiency. Therefore, a multilayer epitaxial growth apparatus and method that can shorten switching time and improve growth uniformity is urgently needed. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a multi-layer epitaxial growth device and method, which solves the technical problems of long switching time and poor doping uniformity in traditional processes by optimizing gas path control and chamber structure.

[0004] In order to solve the above problems, the present invention provides a multi-layer epitaxial growth device, comprising a growth chamber, a plurality of preset pipelines and a control unit, each preset pipeline comprising an epitaxial gas source and a valve group: the epitaxial gas source comprises an intrinsic gas source and a doping source, and the two gas sources are mixed together to form epitaxial gas; the valve group comprises a first valve and a second valve, the first valve connects the epitaxial gas source to the exhaust port, and the second valve connects the epitaxial gas source to the growth chamber; the growth chamber comprises a plurality of air inlets and a plurality of air outlets arranged opposite thereto, the plurality of air inlets are respectively connected to different preset pipelines, and the epitaxial gas is passed into the growth chamber to implement epitaxial growth; the control unit is connected to the plurality of preset pipelines, and controls each preset pipeline to independently select one of the execution of the growth state with the first valve open and the second valve closed, the preparation state with the first valve closed and the second valve open, and the standby state with the first valve closed and the second valve closed.

[0005] Optionally, the intrinsic gas source is a silicon source, and the epitaxial growth equipment is used for silicon epitaxial growth.

[0006] Optionally, the first valve and the second valve are electrically controlled valves.

[0007] Optionally, there are four preset pipelines, corresponding to four air inlets in the growth chamber.

[0008] Optionally, the exhaust port connected to the epitaxial gas source and the valve group is further connected to a vacuum system, so as to use negative pressure to switch the atmosphere to the next state after each preset pipeline is switched from the growth state to the standby state.

[0009] Optionally, the plurality of air inlets are evenly distributed along the sidewalls of the growth chamber.

[0010] In order to solve the above problems, the present invention provides a multi-layer epitaxial growth method, comprising: introducing an epitaxial gas of a first doping concentration into a growth chamber through a first preset pipeline for growth; making a second preset pipeline produce an epitaxial gas of a second concentration and connecting it to an exhaust port to perform pre-growth preparations; after completing the epitaxial growth of the first doping concentration, switching the air intake of the growth chamber from the first preset pipeline to the second preset pipeline to perform epitaxial growth of the second doping concentration.

[0011] Optionally, the epitaxial growth is silicon epitaxial growth.

[0012] The above technical solution eliminates the airflow stabilization time when switching gas lines in traditional processes by preparing the next stage of airflow in parallel, thereby shortening the overall growth cycle. Each pipeline is independently equipped with a mass flow controller, combined with precise timing control of the electronically controlled valve to ensure that there is no fluctuation when switching gases with different doping concentrations. The independent pipeline design completely isolates doping sources of different concentrations or types, which is especially suitable for complex process scenarios such as N-type / P-type doping switching and high and low concentration gradient control. Gas inlets are set in different directions in the reaction chamber, and the formation of a concentration gradient distribution of the doping source on the surface is avoided by adopting a method of timed switching of the gas line inlets. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Attachment Figure 1 Shown is a schematic structural diagram of a preset pipeline and a control unit of a multilayer epitaxial growth device according to a specific embodiment of the present invention.

[0014] Attachment Figure 2 Shown is a schematic structural diagram of a growth chamber of a multilayer epitaxial growth device according to a specific embodiment of the present invention.

[0015] Attachment Figure 3 Shown is a schematic diagram of the implementation steps of a multilayer epitaxial growth method described in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0016] The specific implementation of the multi-layer epitaxial growth device and method provided by the present invention will be described in detail below with reference to the accompanying drawings.

[0017] Attachment Figure 1 FIG2 is a schematic diagram showing the structure of a preset pipeline and a control unit of a multilayer epitaxial growth device according to a specific embodiment of the present invention, Figure 2 FIG. 1 is a schematic diagram of the structure of a growth chamber of a multilayer epitaxial growth device according to a specific embodiment of the present invention. Figure 1 and attached Figure 2The apparatus includes a growth chamber 10, preset pipelines 21-24, and a control unit 30. Each of the preset pipelines 21-24 includes an epitaxial gas source and a valve assembly. This embodiment is described using preset pipeline 21 as an example. The pipeline includes an epitaxial gas source 211 and a valve assembly 212.

[0018] The epitaxial gas source 211 includes an intrinsic gas source 211a and a doping source 211b. In this specific embodiment, the intrinsic gas source 211a is arranged in the gas path upstream of the doping source 211b. The order of the two can be interchanged in other specific embodiments, and the two gas sources are mixed together to form epitaxial gas. In this specific embodiment, the intrinsic gas source 211a is a silicon source, and the epitaxial growth equipment is used for silicon epitaxial growth. The doping source 211b can be selected according to the doping requirements. For different gas paths, the doping sources 211b can be the same or different. The same doping source is used for doping processes of different concentrations of the same doping type, and different doping sources are used for doping processes of different types. In this specific embodiment, preset pipelines 21-24 are included, which can be used for N-type and P-type doping respectively. Two concentrations are set for each doping type to switch between each other. If an intrinsic high-resistance layer is required, the doping source can be cut off. Therefore, the above settings can meet the doping requirements of most processes.

[0019] For silicon epitaxy, common N-type dopant sources such as phosphorus (P), arsenic (As), and antimony (Sb) are delivered to the growth chamber via the vapor phase using phosphine (PH3) gas, arsine (AsH3) gas, and solid sources (such as antimony trioxide, Sb2O3). Common P-type dopant sources such as boron (B) are delivered to the growth chamber using diborane (B2H6) gas. A mass flow controller is installed within the dopant source 211b to precisely control the dopant source gas flow rate and achieve concentration control. This method is suitable for scenarios requiring alternating growth of N-type and P-type epitaxial layers (such as PN junction formation). Different gas paths are configured with non-interfering dopant sources to avoid cross-contamination. For the high-resistance intrinsic layer, all dopant sources can be cut off, allowing only an intrinsic gas source (e.g., a silicon source, such as SiH4 or SiCl4) to be introduced, achieving undoped high-resistance silicon epitaxial growth. Through the above-mentioned material selection and process design, the multi-layer epitaxial growth equipment can flexibly adapt to the needs of N-type / P-type doping switching, high and low concentration gradient control, and intrinsic layer growth, significantly improving the epitaxial growth efficiency and film quality.

[0020] The valve group includes a first valve and a second valve. This specific embodiment is described using the preset pipeline 21 as an example. The pipeline includes an epitaxial gas source 211 and a valve group 212. The valve group 212 includes a first valve 212a and a second valve 212b. The first valve 212a connects the epitaxial gas source 211 to the exhaust port, and the second valve 212b connects the epitaxial gas source 211 to the growth chamber 10. The first valve and the second valve are electrically controlled valves. The control unit 30 is connected to multiple preset pipelines 21-24, and controls each preset pipeline to independently select one of the growth state in which the first valve is open and the second valve is closed, the preparation state in which the first valve is closed and the second valve is open, and the standby state in which the first valve is closed and the second valve is closed. During growth, the preset pipelines 21 and 22 can each be configured as an N-type doping source with a different concentration. Epitaxial gas with a first N-type doping concentration is introduced into the growth chamber through the preset pipeline 21 for growth. After a certain period of growth, the epitaxial gas of the second concentration is generated in pre-set pipeline 22 and connected to the exhaust port. At this point, the gas in pre-set pipeline 22 does not enter the growth chamber 10, but ventilation has already begun. This allows for pre-growth preparations and ensures stable airflow. After epitaxial growth at the first doping concentration is completed, the air inlet to growth chamber 10 is switched from pre-set pipeline 21 to pre-set pipeline 22 to proceed with epitaxial growth at the second N-type doping concentration. At this point, the airflow in pre-set pipeline 22 has stabilized, so the switch can be made without waiting for the airflow to stabilize, saving process time.

[0021] Specifically, during the first concentration growth phase, control unit 30 instructs first valve 212a of pre-set pipeline 21 to open and second valve 212b to close. This allows the intrinsic gas source 211a and N-type dopant source 211b in the pipeline to mix to form an epitaxial gas of the first concentration, which is then introduced through the corresponding gas inlet of growth chamber 10 to initiate epitaxial growth. At this point, pre-set pipeline 22 is in a standby state, with both the first and second valves closed.

[0022] During the pre-venting phase, during the growth process in the pre-designed pipeline 21, the control unit 30 switches the pre-designed pipeline 22 to a standby state. The first valve closes and the second valve opens, allowing the silicon source in this pipeline to mix with the second-concentration N-type dopant source. The gas is then discharged through the exhaust port and does not enter the growth chamber. During this process, the mass flow controller continuously adjusts the dopant source flow rate to gradually stabilize the gas flow concentration.

[0023] Second-Concentration Growth Stage: After the first-concentration epitaxial layer growth is complete, control unit 30 simultaneously performs two operations: preset pipeline 21 switches to a standby or preparation state, and preset pipeline 22 switches to a growth state, with the first valve opening and the second valve closing. At this point, the stabilized second-concentration epitaxial gas enters the growth chamber through the inlet of preset pipeline 22, immediately initiating second-concentration epitaxial growth without waiting for gas flow stabilization. Switching between different doping concentrations can also be performed in a similar manner, enabling rapid switching and saving process time.

[0024] By preparing the next gas flow in parallel, this device eliminates the gas flow stabilization time required during gas line switching in traditional processes, shortening the overall growth cycle. Each pipeline is equipped with an independent mass flow controller, combined with precise timing control of electronically controlled valves, to ensure smooth switching between gases with different dopant concentrations. The independent pipeline design completely isolates dopant sources of different concentrations or types, making it particularly suitable for complex process scenarios such as switching between N-type and P-type doping and controlling high and low concentration gradients.

[0025] The exhaust port connected to the epitaxial gas source 211 and valve assembly 212 is further connected to a vacuum system. This vacuum system is a factory-side vacuum system. This connection method is used to use negative pressure to switch the atmosphere of each preset pipeline from the growth state to the standby state. This connection method uses a negative pressure environment to achieve rapid replacement of the atmosphere within the pipeline, avoiding cross-contamination of gases at different stages and ensuring the stability of the epitaxial growth process.

[0026] Continue to refer to the attached Figure 2 As shown, gas inlets are provided at different directions in the growth chamber 10. In this embodiment, pre-set pipelines 21-24 are included, and correspondingly, multiple gas inlets AD are preferably provided and evenly arranged along the sidewalls of the growth chamber 10. Multiple gas outlets AD are also provided in a corresponding manner.

[0027] The above four air inlets can be used alternately to implement the epitaxial growth process. The timing control logic is shown in the following table. The time, timing, and air inlet direction are all examples and can be independently adjusted according to the actual required epitaxial layer thickness and process characteristics.

[0028] Table 1 Instructions for switching the four air inlets and pipelines

[0029] Gas inlets are positioned at different locations within the reaction chamber and are preferably evenly spaced along the sidewalls of the growth chamber 10. By employing timed switching of gas inlets or the simultaneous use of multiple gas inlets, the apparatus can also avoid the formation of a concentration gradient of the dopant source on the surface for growth processes requiring a constant doping concentration.

[0030] The side wall of the growth chamber 10 is evenly provided with a plurality of air inlets, as shown in the attached Figure 2 Each inlet corresponds to an independent pre-set pipeline, corresponding to pre-set pipelines 21-24. The uniform distribution of the inlets ensures that gas can enter the chamber from different directions and avoids airflow deviation or uneven deposition caused by a single air inlet direction.

[0031] During the growth phase, where the doping concentration remains constant, control unit 30 sequentially switches to enable different gas inlets at preset intervals. For example, in the initial phase, gas inlet A and the corresponding preset pipeline 21 are enabled to flow the epitaxial gas. After a period of time, the second valve of pipeline 21 is closed, and gas inlet B and the corresponding preset pipeline 22 are enabled. At this point, the epitaxial gas composition in pipeline 22 is identical to that in pipeline 21, with only the direction of gas flow changing. This process repeats itself, switching to all gas inlets in a cycle.

[0032] When a single gas inlet is continuously ventilated, the epitaxial gas flow path on the growth surface is fixed, which may lead to the following phenomena: the gas concentration is higher in the area near the gas inlet, resulting in a faster deposition rate; in areas far from the gas inlet, the gas is not replenished in time after consumption, and the concentration gradually decreases, forming a doping concentration gradient from the gas inlet to the gas outlet. However, by regularly switching the gas inlet to allow gas to flow in from different directions, the fixed flow path is broken and localized gas overconsumption or stagnation is avoided. Alternating gas flows from different directions acting on the growth surface can offset the concentration differences caused by a single direction of gas flow, making the adsorption and reaction of the dopant source on the surface more uniform.

[0033] Attachment Figure 3 The figure shows a schematic diagram of the implementation steps of a specific embodiment of the multilayer epitaxial growth method according to a specific embodiment of the present invention, including: step S10, introducing an epitaxial gas of a first doping concentration into a growth chamber through a first preset pipeline for growth; step S11, causing a second preset pipeline to produce an epitaxial gas of a second concentration and connecting it to an exhaust port for pre-growth preparation; step S12, after completing the epitaxial growth of the first doping concentration, switching the air intake of the growth chamber from the first preset pipeline to the second preset pipeline to perform epitaxial growth of the second doping concentration.

[0034] The above steps are implemented using the Figure 1 and attached Figure 2 The device shown in the figure. By preparing the gas flow in parallel, controlling the independent pipelines and designing the multi-directional gas inlet, the efficiency of epitaxial growth and the quality of the thin films are significantly improved. The specific steps are as follows: In step S10, epitaxial gas with a first doping concentration is introduced into the growth chamber through a first preset pipeline for growth. The control unit switches pipeline 21 to open the first valve and close the second valve, and gas is introduced into the growth chamber from the gas inlet A to start epitaxial growth.

[0035] In step S11, the second preset pipeline generates epitaxial gas at a second concentration and connects it to the exhaust port to prepare for growth. During the growth process in pipeline 21 (e.g., 0-20 seconds), the control unit preemptively switches pipeline 22 to a standby state, closing the first valve and opening the second valve. The silicon source and the second-concentration N-type dopant source mix within the pipeline and are discharged through the exhaust port (without entering the growth chamber). The mass flow controller continuously adjusts the flow until it stabilizes. This allows the gas flow to be prepared for the next stage in advance without waiting for the previous stage to complete, eliminating the stabilization time required during the switchover process in traditional processes.

[0036] In step S12, after epitaxial growth at the first doping concentration is complete, the gas flow into the growth chamber is switched from the first preset pipeline to the second preset pipeline, and epitaxial growth at the second doping concentration is performed. When growth at the first concentration is complete (e.g., after 30 seconds), control unit 30 simultaneously switches pipeline 21 to a standby or preparation state and pipeline 22 to a growth state. The first valve opens, the second valve closes, and a stable gas flow of the second concentration is introduced from inlet B. This flow may last for, for example, 30-60 seconds. Because the gas flow in pipeline 22 has already stabilized, growth can be initiated immediately, without requiring additional waiting time.

[0037] For operations requiring higher concentration doping, the above steps can be repeated. The operation examples are as follows. The time intervals are for illustration purposes only. The corresponding relationship with the air inlet is shown in Table 1 above: 30-60 seconds: Air inlet B (preset line 22).

[0038] 60-90 seconds: Air inlet C (preset line 23).

[0039] 90-120 seconds: Air inlet D (preset line 24).

[0040] Parallel pre-venting shortens cycle time: Independent pipelines prepare the next stage of gas flow in advance, eliminating the stabilization time required for switching gas lines in traditional processes. Different dopant sources (e.g., N-type / P-type) are isolated in separate pipelines to prevent mixed contamination, making it suitable for complex processes such as PN junctions. Evenly distributed air inlets on the sidewalls, combined with timed switching, offset concentration gradients caused by unidirectional airflow, improving film quality.

[0041] This method achieves efficient and uniform multi-layer epitaxial growth through independent pipeline control, pre-venting mechanisms, and a multi-directional gas inlet design. This solution is particularly suitable for scenarios requiring frequent switching of doping types or concentrations, providing key technical support for advanced semiconductor processes.

[0042] The above description is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A multilayer epitaxial growth device, characterized in that: The invention comprises a growth chamber, a plurality of preset pipelines and a control unit, wherein each preset pipeline comprises an epitaxial gas source and a valve group: The epitaxial gas source includes an intrinsic gas source and a doping source, and the two gas sources are mixed together to form an epitaxial gas; The valve group includes a first valve and a second valve, wherein the first valve connects the epitaxial gas source to the exhaust port, and the second valve connects the epitaxial gas source to the growth chamber; The growth chamber includes a plurality of air inlets and a plurality of air outlets arranged opposite thereto, wherein the plurality of air inlets are respectively connected to different preset pipelines to pass epitaxial gas into the growth chamber to perform epitaxial growth; The control unit is connected to multiple preset pipelines, controlling each preset pipeline to independently select and execute a growth state in which the first valve is open and the second valve is closed, a preparation state in which the first valve is closed and the second valve is open, and a standby state in which the first valve is closed and the second valve is closed.

2. The device according to claim 1, characterized in that The intrinsic gas source is a silicon source, and the epitaxial growth equipment is used for silicon epitaxial growth.

3. The device according to claim 1, characterized in that The first valve and the second valve are electrically controlled valves.

4. The device according to claim 1, characterized in that There are four preset pipelines, corresponding to four air inlets in the growth chamber.

5. The device according to claim 1, characterized in that The exhaust port connected to the epitaxial gas source and the valve group is further connected to a vacuum system, which is used to switch the atmosphere to the next state using negative pressure after each preset pipeline is switched from the growth state to the standby state.

6. The device according to claim 1, characterized in that The plurality of air inlets are evenly arranged along the sidewall of the growth chamber.

7. A multilayer epitaxial growth method, characterized in that: The steps include: Passing an epitaxial gas with a first doping concentration into the growth chamber through a first preset pipeline for growth; The second preset pipeline is made to produce epitaxial gas of a second concentration and connected to the exhaust port to prepare for growth; After the epitaxial growth of the first doping concentration is completed, the gas inlet of the growth chamber is switched from the first preset pipeline to the second preset pipeline to perform epitaxial growth of the second doping concentration.

8. The method according to claim 7, characterized in that The epitaxial growth is silicon epitaxial growth.

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