Run-vent system for simultaneously depositing layers in a plurality of process chambers of a CVD reactor
By combining vent lines with a single differential pressure sensor and throttling device, the system achieves cost-effective and efficient gas flow regulation across multiple CVD reactor chambers, addressing the complexity and cost issues of prior art systems.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- AIXTRON AG
- Filing Date
- 2025-12-01
- Publication Date
- 2026-06-11
Smart Images
Figure EP2025084852_11062026_PF_FP_ABST
Abstract
Description
Description Run-Vent system for the simultaneous deposition of layers in multiple Process chambers of a CVD reactor field of technology
[0001] The invention relates to a device for the simultaneous deposition of layers on substrates in several process chambers, with mass flow controllers arranged in gas supply lines from gas sources providing reactive gases, wherein the gas supply lines each open into a switching valve with which the reactive gas can be selectively switched either into a run line opening into one of the several process chambers or into a vent line routed past the process chambers, wherein a differential pressure measuring device provides measured values of a pressure difference between the run line and the vent line, with which a control device regulates the pressure difference towards zero, with a stabilizing gas mass flow controller with which a stabilizing gas can be fed into the vent line, and with a throttle valve arranged downstream of the switching valves in the vent line. State of the art
[0002] To deposit a layer onto a substrate in the process chamber of a CVD reactor, the reactive gases are fed into the chamber via a run line, where they decompose pyrolytically, including on the substrate surface. Before the start of this growth process, the reactive gases are not fed directly into the run line, but rather into a vent line that bypasses the process chamber. The vent line stabilizes the gas flow. Once the gas flow is stable, the reactive gases are fed into the run line and thus into the process chamber, with a switching valve controlling the flow of the reactive gas. 31373PCT drg Ai 2024-23 The gas can be selectively fed into either the run line or the vent line. To prevent overflow effects, it is necessary that the total pressure in the vent line corresponds as closely as possible to the total pressure in the run line. In the prior art, a differential pressure sensor is used for this purpose, which provides measured values of the pressure difference between the vent line and the run line. A throttle valve is used to manually set the pressure difference to zero. The pressure difference is then regulated by injecting an inert gas into the vent line upstream of the run-vent switching valve.
[0003] If multiple process chambers are provided in one or more CVD reactors, each process chamber is assigned its own run-vent piping system. This necessitates the use of a variety of components, such as pipes, pressure sensors, valves, and mass flow controllers.
[0004] German patent TW 1557720 B discloses a device for removing a chemical oxide from substrates. It features two process chambers connected by a common gas outlet system. A pressure regulator is provided within the gas outlet system to control the pressure within the process chambers.
[0005] US Patent 2022 / 0090264 discloses a device comprising two process chambers for depositing layers onto substrates. Each process chamber has a gas outlet line that leads into a common gas outlet line. The pressure within each gas outlet line is measured by means of a pressure sensor, whereby the pressure difference between the two gas outlet lines is determined. 31373PCT drg Ai 2024-23 is regulated to a predetermined value by injecting an inert gas into the gas outlet lines. Summary of the invention
[0006] The invention is based on the objective of taking measures to reduce the manufacturing costs of a generic device, and in particular to reduce the number of components within a run-vent piping system supplying several process chambers, as well as to provide a method for operating such a modified device.
[0007] The problem is solved by the device specified in the claims. The dependent claims not only represent advantageous further developments of the technical teachings specified in the dependent claims, but are also independent solutions to the problem.
[0008] The invention provides, first and foremost, that several vent lines are equipped with a single differential pressure sensor. This presupposes that the total pressure in the run lines leading into the multiple process chambers is essentially the same.
[0009] According to a first embodiment of the invention, the vent lines assigned to the multiple process chambers can be combined into a common vent line, in which a throttling device may be arranged. The vent lines are thus combined upstream of the throttling device. The valve position of the throttling device can be varied using the measured values determined by the differential pressure sensor. For this purpose, a control device can be provided that uses the measured values of the differential pressure sensor. 31373PCT drg Ai 2024-23 The valve position of the throttle device is varied in such a way that the pressure difference between the run line and the vent lines is regulated to zero.
[0010] The throttling device can be a throttle valve or a pressure regulator. The setpoint of the pressure regulator can be controlled by the control device in such a way that the differential pressure is minimized, in particular regulated to zero. The throttle valve can also be integrated into the pressure regulator, for example. The pressure regulator can have its own control loop with its own absolute pressure gauge. The throttle valve is the actuator of this control loop.
[0011] A stabilizing mass flow controller allows a stabilizing gas, for example hydrogen and / or nitrogen, to be fed into the vent lines. According to the invention, only one stabilizing mass flow controller is provided, which regulates the mass flow of the stabilizing gas. A gas flow divider can be provided, which divides the stabilizing gas flow supplied by the stabilizing gas mass flow controller into several partial flows, each of which is fed into a vent line. The gas flow divider can, for example, include throttles with which the individual partial flows are controlled. The stabilizing gas mass flow controller can be set to a predetermined value.The active control of the total pressure in the vent lines is therefore, unlike in the prior art, not achieved by controlling the mass flow of the stabilizing gas, but by actively controlling the throttling device, which can be a throttle valve or a pressure regulator.
[0012] Alternatively, the vent lines can also be connected in series, so that the downstream end of an upstream vent line is in 31373PCT drg Ai 2024-23 The upstream end of a downstream vent line terminates in the vent line. The throttling device can be located downstream of the downstream end of the last vent line in the flow direction. Thus, a single vent line can be provided, connected to all run-vent changeover valves assigned to each process chamber, with the run-vent changeover valves arranged sequentially in the vent line. A stabilizing mass flow controller can be provided to regulate the mass flow of the stabilizing gas in the vent line. The differential pressure sensor can be connected to one of the run lines and the vent line. Based on the measured values supplied by the differential pressure sensor, the active valve in the vent line can be controlled. The valve's opening position is adjusted by the control device such that the total pressure in the vent line corresponds to the total pressure in the run lines.
[0013] To determine the differential pressure between the run line and the vent line, an absolute pressure gauge can be provided in at least one of the run lines instead of a differential pressure sensor. For example, an absolute pressure gauge can be arranged in only one of, in particular, several run lines. The pressure regulator can be controlled by the measured value supplied by the absolute pressure gauge, with the pressure regulator increasing the pressure in the vent line so that it corresponds to the pressure in the run lines. Control can preferably be achieved by means of a control device, wherein the absolute pressure gauge transmits a measured value to the control device, which then regulates the pressure regulator based on this measured value. Alternatively, a throttle valve can be provided instead of the pressure regulator, the opening position of which can be set based on the measured values supplied by the differential pressure sensor or the absolute pressure sensor. 31373PCT drg Ai 2024-23
[0014] Alternatively, instead of a differential pressure sensor, two absolute pressure sensors can be used to measure the differential pressure. One of the absolute pressure sensors can be located in one of the run lines, and the other in a vent line associated with the run line. The absolute pressure in the vent line can also be measured using a sensor in the pressure regulator instead of an absolute pressure gauge. Furthermore, the absolute pressure in the run line can also be estimated using the process chamber pressure and, if necessary, a correction value that depends on the mass flow through the run line.
[0015] Furthermore, the differential pressure can also be determined in the control loop of the pressure regulator, for example by comparing the actual value of the absolute pressure in the vent line with the actual value of the absolute pressure in the run line, whereby the actual value of the absolute pressure of the run line is transmitted to the pressure regulator as a setpoint and the difference is determined by means of the pressure regulator.
[0016] By actively regulating the total pressure in the vent lines, unlike in the prior art, not in the inflow by means of the stabilizing mass flow controller, but downstream of the injection point of the reactive gas into the vent lines by means of the throttle valve or pressure regulator located there, it is ensured that the gas flow through the vent lines is constant at all times.
[0017] The vent line can lead into a gas outlet system of the CVD reactor. A pump, in particular a vacuum pump, can be located within the gas outlet system. The gas flow in the vent is kept constant. 31373PCT drg Ai 2024-23 The piping can reduce the gas load on this pump. The vent lines can be connected to a gas outlet system, into which the gases from the process chambers of the CVD reactor are also fed, or to a separate gas outlet system.
[0018] The stabilizing flow can be divided into equal partial flows using throttles. The throttles are located, in particular, immediately downstream of the division point where the stabilizing gas flow is split into the partial flows.
[0019] It is considered advantageous that only one differential pressure gauge is required.
[0020] The device has several process chambers into which reactive gases are fed during operation. These gases decompose within the process chamber, enabling the deposition of layers onto substrates arranged therein. According to the invention, the same deposition processes are carried out simultaneously in the multiple process chambers. Thus, substrates of the same type, for example, III-V substrates or IV substrates, are coated with the same layers or layer sequences. Several deposition processes are therefore performed simultaneously according to the same common formula. Each process chamber is assigned a group of mass flow controllers, with each mass flow controller in the group regulating the mass flow of a reactive gas or the mass flow of a carrier gas.The setpoints of these mass controllers, assigned to the different groups, are identical, ensuring that the same mass flows pass through the run lines and the vent lines. These are the two pipe systems assigned to the different process chambers. 31373PCT drg Ai 2024-23 They are essentially identical in construction, so the same pressures prevail in these pipes. Therefore, it may be sufficient to operate the entire device with only one absolute pressure gauge in one of the run lines. Brief description of the drawings
[0021] Exemplary embodiments of the invention are explained with reference to the accompanying drawings. These show: Fig. 1 shows a circuit diagram of a run-vent line system known from the prior art, wherein each of the two process chambers 1, 2 is assigned a run line 8, 9 and a vent line 10, 11, wherein a differential pressure sensor 13, 13' and a throttling device 7, 7' comprising two throttle valves are arranged in each vent line 10, 11. Fig. 2 shows a circuit diagram of a first embodiment in which only one differential pressure sensor 13 is provided, which supplies measured values of a pressure difference between one of the two run lines 8 and a vent line 10, wherein the vent lines 10, 11 are combined into a common vent line in which a throttle device 12 designed as a pressure regulator is arranged, which is controlled by a control device 32 with the measured values supplied by the differential pressure sensor 13. Fig. 3 shows a circuit diagram of a second embodiment in which the vent lines 10, 11 are connected in series. 31373PCT drg Ai 2024-23 Fig. 4 shows a circuit diagram according to Figure 3 of a third embodiment, wherein an absolute pressure gauge 33 is arranged in one of the run lines 8, which provides measured values with which a throttle device 12 arranged in the vent line 10, designed as a pressure regulator, is controlled. Description of the embodiments
[0022] Figure 1 shows a circuit diagram of a prior art run-vent system of a CVD reactor, which has two process chambers 1, 2. A run line 8, 9 opens into each of the two process chambers 1, 2, through which reactive gases can be fed into the process chambers 1, 2. The reactive gases are supplied by gas sources 3, 4. The mass flow of the reactive gases flowing from the gas sources 3, 4 is controlled by a mass flow controller 22, 23. Diverter valves 28, 29 are provided, with which the reactive gases can be selectively fed either into the run lines 8, 9 or into vent lines 10, 11 that bypass the process chambers 1, 2.
[0023] Each of the two vent lines 10, 11 is assigned a differential pressure sensor 13, 13', which measures the pressure difference between the vent line 10, 11 and its associated run line 8, 9. Downstream of the changeover valves 28, 29, a throttle valve 7, 7' is arranged in each of the vent lines 10, 11. The throttle valve 7, 7' is a passive valve whose opening is manually adjusted. The throttle valve 7, 7' is, for example, a needle valve that functions as a throttle. The throttle valve 7, 7' sets the pressure difference to zero. The pressure difference between the run line 8, 9 and the vent line 10, 11 is regulated by injecting a stabilizing gas supplied by a stabilizing gas source 16, 16' upstream of the switching valves 28, 29. The mass flow 31373PCT drg Ai 2024-23 The flow of the stabilizing gas is controlled by a stabilizing gas mass flow controller 18. Furthermore, a control device 32 is provided which uses the measured values supplied by the differential pressure sensors 13, 13' to control the stabilizing gas mass flow controller 18 in order to regulate the pressure difference.
[0024] Figure 2 shows a circuit diagram of a first embodiment of the run-vent system according to the invention. Unlike the prior art shown in Figure 1, only one differential pressure sensor 13 is provided, which measures the pressure difference between one of the run lines 8 and the vent lines 10, 11. It is assumed that the total pressure in the run lines 8, 9 is essentially the same. This is particularly the case when the same coating process is carried out in the several process chambers 1, with the two coating processes being carried out simultaneously, so that the same mass flows pass through the run lines 8, 9 and all valves 24 to 26, 28, 29 are switched simultaneously.
[0025] The vent lines 10 and 11 are joined downstream of the changeover valves 28 and 29 in a common vent line 34. Only one throttling device 12 is provided, which is located in the common vent line 34. The throttling device 12 actively controls the total pressure in the vent lines 10 and 11. Here, the throttling device 12 acts as a pressure regulator. The pressure regulator 12 can include an absolute pressure sensor and a control loop. A throttle valve can be controlled by the control loop; alternatively, a throttle valve can also be located in the common vent line 34 instead of the pressure regulator 12.
[0026] Furthermore, only one stabilizing mass flow controller 18 is provided, which regulates a stabilizing gas mass flow supplied by the stabilizing gas source 16. The stabilizing gas mass flow controller 31373PCT drg Ai 2024-23 The stabilizing gas flow supplied by the 18 is divided into several partial flows by a gas flow divider having throttles 30, 31. The partial flows are each fed into one of the vent lines 10, 11. The stabilizing gas mass flow controller 18 is preset so that the gas flow through the vent lines 10, 11 is kept constant. The differential pressure, on the other hand, is controlled based on the measured values supplied by the differential pressure gauge 13, whereby the measured values are transmitted to the control unit 32, which uses the measured values to control the position of a throttle valve of the throttling device 7. The throttles 30, 31 can be configured such that the same flows pass through the vent lines 10, 11.
[0027] Figure 3 shows a second embodiment of the invention. Unlike the embodiment shown in Figure 2, the individual run-vent changeover valves 28, 29 are not arranged parallel to each other, but in series, so that the reactive gases are fed directly into a common vent line 34. A throttling device 7 is arranged downstream of the changeover valves 28, 29 in the common vent line 34, which is controlled by the control device 32 by means of the measured values supplied by the differential pressure gauge 13. The throttling device 7 can again be a pressure regulator having a throttle valve, or a throttle valve itself.
[0028] If deposition processes are carried out simultaneously in process chambers 1, 2 according to identical recipes, the absolute pressures in the two run lines 8, 9 are almost identical.
[0029] As shown in Figure 4, the differential pressure gauge can be replaced by... 13 an absolute pressure gauge 33 be arranged in one of the run lines 8 31373PCT drg Ai 2024-23 The throttling device 12 arranged in the common vent line 34 downstream of the switching valves 28, 29 can also be a pressure regulator 12. The absolute pressure gauge 33 provides measured values with which the pressure regulator 12 is controlled. A gas outlet system (not shown) can be connected to the pressure regulator 12, through which gases routed from the process chambers 1, 2 are supplied to a disposal device. The pressure in the process chambers 1, 2 is controlled by a pump. The active pressure regulator 12 has the advantage over a passive throttle valve that the total pressure in the vent line 34 downstream of the throttle valve or the pressure regulator 12 does not have to correspond to the level of the pressure prevailing in the process chambers 1, 2; in particular, the pressure regulator can be arranged directly on its outlet side with the inlet of the pump downstream of a pressure regulating valve of the process chambers 1, 2. The pump can be located downstream of process chambers 1 and 2.It is possible to use only one pump to pump the exhaust gases generated in process chambers 1 and 2 out of those chambers. A pressure regulating device can be used to adjust the total pressure in process chambers 1 and 2.
[0030] The foregoing statements serve to explain the inventions covered by the application as a whole, which each independently further develop the prior art at least through the following combinations of features, whereby two, several or all of these combinations of features may also be combined, namely:
[0031] A device characterized in that the vent lines 10, 11 assigned to the several process chambers 1, 2 are joined upstream of the throttling device 7, 12, wherein the control device- 31373PCT drg Ai 2024-23 hing 32 with the measured values controls the throttle device 7 , 12 and in particular varies a valve position of a throttle valve 7 of the throttle device 7 , 12.
[0032] A device characterized in that the stabilizing gas flow supplied by the stabilizing gas mass flow controller 18 is divided into several partial flows by means of a gas flow divider and the gas flow divider feeds the partial flows into each of the vent lines 10, 11.
[0033] A device characterized in that the vent lines 10, 11 are connected in series, such that the downstream end of an upstream vent line 10 opens into an upstream end of a downstream vent line 11 and the throttle valve 7 is arranged downstream of the downstream end of the last vent line 11 in the flow direction.
[0034] A device characterized by throttles 30, 31 arranged directly downstream of the division point where the stabilizing gas flow is divided into the partial flows, which in particular divide the stabilizing gas flow into equal partial flows.
[0035] A device characterized in that the vent lines 10, 11 are connected in series, such that the downstream end of an upstream vent line 10 opens into an upstream end of a downstream vent line 11 and a throttling device 7, 12 is arranged downstream of the downstream end of the last vent line 11 in the flow direction, wherein an absolute pressure gauge 33 arranged in at least one, preferably only one of the vent lines 8, 9 provides a measured value with which a control device 32 controls the pressure regulator 12. 31373PCT drg Ai 2024-23
[0036] A process characterized in that separation processes are carried out simultaneously in the several process chambers 1, 2 according to the same recipe, so that the same gas flows are fed into the several process chambers 1, 2 simultaneously through the gas supply lines 5, 6.
[0037] A method characterized in that, during the processing of the recipe, the switching valves 28, 29, which are individually assigned to the various process chambers 1, 2, are switched synchronously.
[0038] A device or method characterized in that the throttling device 7, 12 is a pressure regulator 12, which in particular has a control loop cooperating with an absolute pressure sensor 33 and a throttle valve 7, or is a throttle valve 7.
[0039] All disclosed features are essential to the invention (individually, but also in combination with one another). The disclosure of this application hereby incorporates in full the disclosure content of the associated / attached priority documents (copy of the earlier application), also for the purpose of including features of these documents in the claims of the present application. The dependent claims, even without the features of a referenced claim, characterize independent inventive developments of the prior art, in particular for the purpose of filing divisional applications based on these claims. The invention specified in each claim may additionally comprise one or more of the features described above, in particular those identified by reference numerals and / or listed in the reference numeral list.The invention also relates to design forms in which some of the features mentioned in the preceding description are not realized, in particular. 31373PCT drg Ai 2024-23 insofar as they are recognizably unnecessary for the respective purpose or can be replaced by other technically equivalent means. 31373PCT drg Ai 2024-23 List of reference symbols 1 process chamber 21 mass flow controller Process chamber 22 mass flow controller Gas source 23 mass flow controller Gas source 23' mass flow controller Gas supply line 24 shut-off valve Gas supply line 25 shut-off valve Throttle valve 26 Shut-off valve Throttle valve 27 Shut-off valve Run line 28 Run-Vent changeover valve Run line 28' Run-Vent changeover valve Vent line 29 Run-Vent changeover valve Vent line 30 throttle Pressure regulator 31 throttle Differential pressure gauge 32 Control unit Differential pressure gauge 33 Absolute pressure gauge Dilution gas source 34 common vent line Dilution gas source Stabilizing gas source Stabilizing gas source Mass flow controller Stabilizing gas mass flow regulator Mass flow controller Mass flow controller 31373PCT drg Ai 2024-23
Claims
Claims 1. Device for the simultaneous deposition of layers onto substrates in several process chambers (1, 2) with gas sources (3, 4) for providing reactive gases, wherein gas supply lines (5, 6) connected to the gas sources (3, 4) each open into a switching valve (28, 29), by which the reactive gas can be selectively switched either into a run line (8, 9) opening into one of the several process chambers (1, 2) or into a vent line (10, 11) routed past the process chambers (1, 2), wherein a differential pressure measuring arrangement (13) provides measured values of a pressure difference between the run line (8, 9) and the vent line (10, 11), with which a control device (32) regulates the pressure difference towards zero, with a stabilizing gas mass flow controller (18), by which a stabilizing gas, in the vent line (10, 11) can be fed in, and with a throttling device (7, 12) arranged downstream of the switching valves (28, 29) in the vent line (10, 11),characterized in that the vent lines (10, 11) assigned to the several process chambers (1, 2) are joined upstream of the throttling device (7, 12), wherein the control device (32) controls the throttling device (7, 12) with the measured values and in particular varies a valve position of a throttle valve (7) of the throttling device (7, 12).
2. Device according to claim 1, characterized in that the stabilizing gas flow supplied by the stabilizing gas mass flow controller (18) is divided into several partial flows by means of a gas flow divider and the gas flow divider feeds the partial flows into one of the vent lines (10, 11) each. 31373PCT drg Ai 2024-23 3. Device according to claim 1, characterized in that the vent lines (10, 11) are connected in series, such that the downstream end of an upstream vent line (10) opens into an upstream end of a downstream vent line (11) and the throttle valve (7) is arranged downstream of the downstream end of the last vent line (11) in the flow direction.
4. Device according to claim 2, characterized by throttles (30, 31) arranged directly downstream of the division point where the stabilizing gas flow is divided into the partial flows, which in particular divide the stabilizing gas flow into equal partial flows.
5. Device for the simultaneous deposition of layers on substrates in several process chambers (1, 2) with gas sources (3, 4) for providing reactive gases, wherein gas supply lines (5, 6) connected to the gas sources (3, 4) each open into a switching valve (28, 29), with which the reactive gas can be selectively switched either into a run line (8, 9) opening into one of the several process chambers (1, 2) or into a vent line (10, 11) routed past the process chambers (1, 2), with a stabilizing gas mass flow controller (18) with which a stabilizing gas can be fed into the vent line (10, 11), characterized in that the vent lines (10, 11) are connected in series, such that the downstream end of an upstream vent line (10) opens into an upstream end of a downstream vent line (11) and a throttling device (7,12) is located downstream of the downstream end of the last vent line (11) in the direction of flow, 31373PCT drg Ai 2024-23 wherein an absolute pressure measuring device (33) arranged in at least one, preferably only one of the run lines (8, 9) provides a measured value with which a control device (32) controls the pressure regulator (12).
6. Method for the simultaneous deposition of layers on substrates in several process chambers (1, 2) with a device according to one of claims 1 to 5, characterized in that deposition processes according to the same recipe are carried out simultaneously in the several process chambers (1, 2), so that the same gas flows are fed into the several process chambers (1, 2) simultaneously through the gas supply lines (5, 6).
7. Method according to claim 6, characterized in that, during the processing of the recipe, the switching valves (28, 29) individually assigned to the various process chambers (1, 2) are switched synchronously.
8. Device or method according to one of the preceding claims, characterized in that the differential pressure measuring arrangement (13) is formed by a differential pressure measuring device (13) or two absolute pressure measuring devices (33).
9. Device or method characterized in that the throttling device (7, 12) is a pressure regulator (12) which in particular has a control loop cooperating with an absolute pressure sensor (33) and a throttle valve (7) or is a throttle valve (7).
10. Device or method characterized by one or more of the characterizing features of one of the preceding claims. 31373PCT drg Ai 2024-23