A quantitative precursor supply system and method for atomic layer deposition

Abstract

The application discloses a kind of quantitative precursor supply system and method for atomic layer deposition, it is related to the field of semiconductor manufacturing technology.The system includes precursor source bottle, controller and at least one set of buffer unit between source bottle and reaction cavity.Each buffer unit includes a first control valve, dose buffer zone and a second control valve, and a pressure monitoring component is arranged in the buffer zone.The controller controls the buffer unit to perform filling cycle and release cycle, and controls the valve opening and closing based on the pressure reaching the preset target value during filling;Multiple buffer units can be alternately executed to improve efficiency.The application eliminates the dose drift caused by precursor consumption through the pressure reference quantitative mechanism, ensures the long-term stability of film growth rate, and aims to meet the stringent requirements of advanced process on thickness control and consistency.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a quantitative precursor supply system and method for atomic layer deposition. Background Technology

[0002] In atomic layer deposition (ALD) processes, the stability of precursor supply directly affects the film growth rate, uniformity, and final module performance. Existing technologies typically employ carrier gas bubbling, vapor extraction, or thermal sublimation to deliver precursors to the reaction chamber. These supply methods primarily rely on the vapor pressure state of the precursor source container itself for direct supply. However, during long-duration continuous processes, as the precursor source is gradually consumed, the headspace volume within the container continuously increases, accompanied by changes in the gas-liquid or gas-solid equilibrium state. This leads to fluctuations in the time and stability of the source container's vapor pressure build-up.

[0003] In this scenario, even if the valve opening time remains constant, the actual number of precursor moles entering the reaction chamber will shift over time, resulting in dose drift. This dose drift directly affects the self-limiting property upon which atomic layer deposition (ALD) depends, causing a change in the film growth rate per cycle. As the number of deposition cycles increases, the error accumulates, leading to deviations between the final film thickness and electrical parameters.

[0004] Therefore, how to achieve precise control of precursor dosage to eliminate dose drift has become a technical problem that urgently needs to be solved. Summary of the Invention

[0005] The main objective of this invention is to provide a quantitative precursor supply system and method for atomic layer deposition, which aims to achieve precise control of precursor dosage to eliminate dose drift.

[0006] To achieve the above objectives, the present invention proposes a quantitative precursor supply system for atomic layer deposition, comprising: Precursor source bottle, used to provide gaseous precursors; Controller; And at least one set of buffer units disposed between the precursor source bottle and the reaction chamber; each set of buffer units includes a first control valve, a dose buffer and a second control valve, one end of the first control valve is in fluid communication with the precursor source bottle and the other end is in communication with the dose buffer, one end of the second control valve is in communication with the dose buffer and the other end is used to communicate with the reaction chamber, and a pressure monitoring component is disposed in the dose buffer; The controller is configured to control the at least one set of buffer units to perform filling and releasing cycles: During the filling cycle, the corresponding first control valve is opened to allow the gaseous precursor to enter the dose buffer, and the first control valve is closed when the real-time pressure detected by the pressure monitoring component reaches the preset target pressure value. During the release cycle, the corresponding second control valve is opened to release the gaseous precursor within the dose buffer.

[0007] Preferably, at least two sets of buffer units are arranged in parallel; the controller is configured to control the at least two sets of buffer units to alternately execute the filling cycle and the releasing cycle, wherein when the controller controls the first set of buffer units to execute the releasing cycle, it simultaneously controls the second set of buffer units to execute the filling cycle.

[0008] Preferably, it also includes a multi-stage heating assembly for heating the precursor source bottle, the dose buffer zone, and the connecting pipeline respectively; The controller is also configured to maintain the temperature of the multi-stage heating assembly such that the temperature of the dose buffer is higher than the temperature of the precursor source bottle, and the temperature of the connecting pipeline between the second control valve and the reaction chamber is higher than the temperature of the dose buffer.

[0009] Preferably, the temperature of the dose buffer is higher than the temperature of the precursor source bottle. to .

[0010] Preferably, the dose of the gaseous precursor entering the dose buffer during the filling cycle is determined by the target pressure value, the volume of the dose buffer, and the temperature.

[0011] Preferably, the controller is further configured to: calculate the pressure rise slope within the dose buffer based on pressure changes fed back by the pressure monitoring component during the filling cycle. When the pressure rise slope When the temperature is below a preset threshold, the opening time of the first control valve is automatically extended, or the heating temperature of the precursor source bottle is increased.

[0012] Preferably, the dose buffer has a variable volume structure, which is a bellows structure.

[0013] Preferably, the second control valve is a pulse valve specifically designed for atomic layer deposition.

[0014] This application also discloses a method for quantitative supply control of precursors for atomic layer deposition, using the quantitative precursor supply system for atomic layer deposition as described in any of the preceding claims, the method comprising: Control the at least one set of buffer units to perform filling and releasing cycles; The filling cycle includes: opening the first control valve to allow the gaseous precursor to enter the dose buffer from the precursor source bottle, and using a pressure monitoring component to detect the pressure in the dose buffer in real time. When the pressure reaches a preset target pressure value, the first control valve is closed. The release cycle includes: opening the second control valve to release the quantified gaseous precursor in the dose buffer into the reaction chamber.

[0015] Preferably, at least two sets of buffer units are arranged in parallel; the method further includes: controlling the at least two sets of buffer units to alternately execute the filling cycle and the releasing cycle, wherein when the first set of buffer units executes the releasing cycle, the second set of buffer units is simultaneously controlled to execute the filling cycle.

[0016] Preferred options also include: The precursor source bottle, the dose buffer, and the connecting pipeline are heated in segments, and a temperature gradient is maintained so that the temperature of the dose buffer is higher than the temperature of the precursor source bottle, and the temperature of the connecting pipeline between the second control valve and the reaction chamber is higher than the temperature of the dose buffer.

[0017] Preferred options also include: During the filling cycle, the pressure rise slope within the dose buffer is calculated based on the pressure changes fed back by the pressure monitoring component. When the pressure rise slope When the temperature is below a preset threshold, the opening time of the first control valve is automatically extended, or the heating temperature of the precursor source bottle is increased.

[0018] The above technical solution has the following advantages: This invention establishes a pressure-based quantitative supply mechanism by setting at least one set of buffer units and a pressure monitoring component. Since the number of precursor moles entering the reaction chamber with each pulse is determined by the target pressure value and fixed volume within the dose buffer, rather than depending on the real-time vapor pressure of the precursor source bottle, dose drift caused by precursor consumption in the source bottle is effectively eliminated, ensuring a constant film growth rate and batch-to-batch consistency throughout the entire process. Furthermore, when multiple buffer units are set, the controller can employ parallel alternating logic, synchronously controlling the second buffer unit to perform a filling cycle while the first buffer unit performs a release cycle. This eliminates the waiting time caused by the slow sublimation rate of the precursor, achieving high-frequency pulse supply and significantly improving system throughput. Attached Figure Description

[0019] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings, wherein: Figure 1 This is a schematic diagram of a quantitative precursor supply system for atomic layer deposition provided in an embodiment of the present invention. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. The embodiments listed herein are for illustrative purposes only and do not constitute a limitation on the scope of protection of the present invention. Without departing from the essential spirit of the present invention, those skilled in the art can make various improvements and substitutions based on the technical solutions of the present invention, and all such improvements and substitutions should be covered within the scope of protection of the present invention.

[0021] Example 1 like Figure 1 As shown, this embodiment provides a quantitative precursor supply system for atomic layer deposition, which mainly addresses the technical problem in the prior art where precursor supply dosage drift occurs during precursor consumption due to changes in the volume of the top space within the container, alterations in the adsorption state on the inner wall, and fluctuations in thermal equilibrium. This system, by introducing a pressure feedback mechanism and a dual-path redundant buffer structure, achieves precise control and continuous supply of the precursor dosage, thereby ensuring a highly stable and repeatable mass transfer rate.

[0022] Specifically, the quantitative precursor supply system for atomic layer deposition includes a precursor source bottle 1, a controller 2, and at least one set of buffer units disposed between the precursor source bottle 1 and the reaction chamber 3. The precursor source bottle 1 is specifically a high-pressure resistant and corrosion-resistant steel cylinder, which contains the liquid or solid precursor. The precursor source bottle 1 is externally covered with a heating assembly. The controller 2 adjusts the heating power to maintain the precursor source bottle 1 at a specific process temperature, such as a constant value between 120°C and 150°C, thereby sublimating the solid precursor into a gaseous precursor or bringing the liquid precursor to its saturated vapor pressure state. Furthermore, as... Figure 1 As shown, the system also includes a mass flow controller (MFC) and auxiliary pipelines. The mass flow controller is used to control the flow rate of the carrier gas, which is introduced into the precursor source bottle 1 to assist in the foaming or vaporization of the precursor, or to assist in pushing the precursor vapor into the subsequent pipeline system through the bypass pipeline.

[0023] In this embodiment, the system is equipped with two sets of parallel buffer units, namely a first buffer unit and a second buffer unit. The first buffer unit includes a first control valve A1, a first dose buffer A3, and a second control valve A2. One end of the first control valve A1 is connected to the outlet of the precursor source bottle 1 via a pipeline, and the other end is connected to the inlet of the first dose buffer A3. One end of the second control valve A2 is connected to the outlet of the first dose buffer A3, and the other end leads to the reaction chamber 3. A pressure monitoring component is installed in the first dose buffer A3, specifically a high-precision capacitive pressure gauge PG, which is used to collect the pressure data inside the first dose buffer A3 in real time and feed it back to the controller 2.

[0024] Similarly, the second buffer unit includes a first control valve B1, a second dose buffer B3, and a second control valve B2. One end of the first control valve B1 is in fluid communication with the precursor source bottle 1, and the other end is in communication with the second dose buffer B3. One end of the second control valve B2 is in communication with the second dose buffer B3, and the other end is used to communicate with the reaction chamber 3. An independent pressure gauge PG is also installed in the second dose buffer B3.

[0025] In the system operation of this embodiment, controller 2 is configured to control the two sets of buffer units to alternately perform filling and releasing cycles. Specifically, the filling cycle includes the following steps: First, controller 2 opens the corresponding first control valve A1, allowing the gaseous precursor to enter the first dose buffer A3 from the precursor source bottle 1 under the action of pressure difference, while the second control valve A2 remains closed. During the filling process, controller 2 monitors the pressure value fed back by pressure gauge PG in real time. When the real-time pressure reaches the preset target pressure value... At this time, controller 2 immediately outputs a command to close the first control valve A1. At this point, the amount of precursor substance stored in the first dose buffer A3, i.e., the number of moles... The molar number of the gaseous precursor was calculated using physical formulas. The calculation formula is:

[0026] In Equation 1 above, The molar number of the gaseous precursor. For the set target pressure value, The fixed volume of the first dose buffer A3, This is the universal gas constant, and its value is approximately equal to 8.314 J / mol·K. This is the real-time absolute temperature of the first dose buffer A3. Because... and It is a constant, and Controlled by a constant temperature environment, therefore the number of moles entering the buffer zone in each batch is limited. It depends entirely on the target pressure value This is unaffected by the amount of precursor remaining in the source bottle 1, thus effectively eliminating dose drift caused by the increase in top space of the source bottle, ensuring that the film growth rate remains constant in each cycle, and meeting the requirements for batch-to-batch consistency.

[0027] After the first buffer unit is filled, the system enters a release cycle. At this time, controller 2 opens the corresponding second control valve A2, releasing the pre-quantitative gaseous precursor in the first dose buffer A3 into the reaction chamber 3 for use in the atomic layer deposition reaction. To improve production efficiency, controller 2 adopts parallel alternating logic, that is, when the first set of buffer units executes the release cycle, it synchronously controls the second set of buffer units to execute the filling cycle, preparing the dose required for the next pulse in the second dose buffer B3. In this way, when the first dose buffer A3 is completely released, the second dose buffer B3 is already prepared with the precise dose required for the next pulse, thereby eliminating the waiting time caused by the slow sublimation rate of the solid precursor and realizing high-frequency pulse supply.

[0028] To ensure that the gaseous precursor does not condense during transport and to protect precision components, the quantitative precursor supply system also includes a multi-stage heating assembly. This multi-stage heating assembly is independently encased in the precursor source bottle 1, the first dose buffer A3, the second dose buffer B3, and all connecting pipelines. The controller 2 is also configured to maintain a temperature gradient in the multi-stage heating assembly, ensuring it conforms to specific thermodynamic laws. Specifically, the controller 2 maintains the temperatures of the first dose buffer A3 and the second dose buffer B3 slightly higher than the temperature of the precursor source bottle 1 through closed-loop control. In this embodiment, the temperature of the dose buffers is 5°C to 10°C higher than the temperature of the precursor source bottle 1. Simultaneously, the temperature of the connecting pipeline between the second control valve A2 and the reaction chamber 3 is set slightly higher than the temperature of the dose buffers. This gradient control method, with temperature gradually increasing from the source to the reaction end, ensures that the precursor is always in a superheated vapor state, completely eliminating the possibility of pipeline blockage and particulate contamination.

[0029] Furthermore, the system also features intelligent prediction and compensation functions. During the filling cycle, controller 2 calculates the rate of rise (ROR) within the buffer zone based on the pressure change over time, as fed back by pressure gauge PG. When controller 2 detects that the ROR is lower than a preset threshold, it indicates that the precursor in precursor source bottle 1 may be nearing depletion or that sublimation efficiency has significantly decreased. At this time, controller 2 automatically executes a compensation program, such as extending the opening time of the first control valve A1 to ensure the pressure reaches the target value, or appropriately increasing the heating temperature of precursor source bottle 1 to enhance the sublimation driving force.

[0030] In this embodiment, both the second control valve A2 and the second control valve B2 are preferably pulse valves specifically designed for atomic layer deposition. These valves have extremely short response times, typically less than 10 ms, enabling them to work with high-frequency pulse processes. The volumes of the first dose buffer A3 and the second dose buffer B3 can be customized according to the size of the reaction chamber 3.

[0031] Example 2 Building upon Example 1, this example further optimizes the physical structure of the dose buffer to enhance the system's adaptability to different process requirements. Specifically, both the first dose buffer A3 and the second dose buffer B3 can employ a variable volume structure. This variable volume structure is specifically a bellows structure. By adjusting the extension and retraction length of the bellows, the effective volume of the dose buffer can be flexibly adjusted according to the size of the deposition chamber or the single pulse dose required for a specific process. To adapt to different process windows. When the bellows is controlled by an external precision lead screw or pneumatic actuator, its volume changes linearly. Controller 2 updates the calculation formula in real time based on the displacement feedback from the sensor. Parameters are used to achieve dose adjustment across ranges without changing the hardware.

[0032] Example 3 This embodiment details the intelligent monitoring logic of the system during the filling cycle. Controller 2 is configured to calculate the pressure rise rate (ROR) within the first dose buffer A3 or the second dose buffer B3 during the filling cycle, based on the rate of change of pressure over time fed back by pressure gauge PG. The formula for calculating the pressure rise rate (ROR) is as follows:

[0033] In Equation 2 above, The pressure value detected at the current moment. The pressure value detected at the previous moment. The sampling time interval is specified. Controller 2 has a preset slope threshold. When the pressure rise slope ROR calculated in real time is lower than this preset threshold, it means that the gaseous precursor flux provided by precursor source bottle 1 is insufficient. This usually indicates that the solid precursor in precursor source bottle 1 has been consumed to the critical point, resulting in a reduction in the effective sublimation area, or a slower vapor pressure build-up rate in the source bottle.

[0034] In such cases, controller 2 will automatically trigger a compensation mechanism. One compensation method is to automatically extend the opening duration of the corresponding first control valve (e.g., A1 or B1) to ensure that the pressure eventually reaches the preset target pressure value. This ensures the number of moles for each pulse. Maintaining a constant temperature. The second compensation method is to automatically increase the set temperature of the external heating assembly of the precursor source bottle 1, for example, by increasing the heating margin by 2°C to 5°C, thereby increasing the filling rate by raising the saturated vapor pressure. If the pressure rise slope (ROR) does not improve after compensation and continues to decrease, the controller 2 will output an alarm signal to remind the operator to replace the precursor source bottle 1, thus effectively avoiding process failures caused by precursor depletion.

[0035] Example 4 This embodiment provides a multi-group expansion scheme to meet the complex process requirements of ultra-high frequency pulse or mixed deposition of multiple precursors. In addition to the first and second buffer units mentioned above, this quantitative precursor supply system can be expanded to three, four, or more groups of buffer units connected in parallel, depending on actual needs. For example, when preparing doped thin films or nanolayered thin films, different precursor source bottles can be connected to different buffer unit groups. By independently timing each group of buffer units through the controller 2, precise alternating injection of multiple precursors within the reaction chamber 3 can be achieved. Under this multi-path alternating operation mechanism, the system can complete the deposition of multiple atomic layers in a very short cycle, significantly improving the overall throughput and process flexibility of the system, and enhancing process reproducibility.

[0036] In summary, the quantitative precursor supply system for atomic layer deposition provided by this invention effectively overcomes the dose drift problem caused by precursor source consumption in traditional atomic layer deposition systems through a pressure-based quantitative mechanism and multi-channel alternating operation logic. This invention not only ensures the long-term stability of the film growth rate but also improves the system's throughput and reliability when processing low vapor pressure solid precursors through precise temperature gradient control and intelligent slope compensation, meeting the stringent requirements of advanced processes for thickness control and consistency.

[0037] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A quantitative precursor supply system for atomic layer deposition, characterized in that, include: Precursor source bottle, used to provide gaseous precursors; Controller; And at least one set of buffer units disposed between the precursor source bottle and the reaction chamber; each set of buffer units includes a first control valve, a dose buffer and a second control valve, one end of the first control valve is in fluid communication with the precursor source bottle and the other end is in communication with the dose buffer, one end of the second control valve is in communication with the dose buffer and the other end is used to communicate with the reaction chamber, and a pressure monitoring component is disposed in the dose buffer; The controller is configured to control the at least one set of buffer units to perform filling and releasing cycles: During the filling cycle, the corresponding first control valve is opened to allow the gaseous precursor to enter the dose buffer, and the first control valve is closed when the real-time pressure detected by the pressure monitoring component reaches the preset target pressure value. During the release cycle, the corresponding second control valve is opened to release the gaseous precursor within the dose buffer.

2. The quantitative precursor supply system for atomic layer deposition according to claim 1, characterized in that, The buffer units are arranged in at least two sets in parallel; the controller is configured to control the at least two sets of buffer units to alternately execute the filling cycle and the releasing cycle, wherein when the controller controls the first set of buffer units to execute the releasing cycle, it simultaneously controls the second set of buffer units to execute the filling cycle.

3. The quantitative precursor supply system for atomic layer deposition according to claim 1, characterized in that, It also includes a multi-stage heating assembly for heating the precursor source bottle, the dose buffer, and the connecting pipeline respectively; The controller is also configured to maintain the temperature of the multi-stage heating assembly such that the temperature of the dose buffer is higher than the temperature of the precursor source bottle, and the temperature of the connecting pipeline between the second control valve and the reaction chamber is higher than the temperature of the dose buffer.

4. The quantitative precursor supply system for atomic layer deposition according to claim 3, characterized in that, The temperature of the dose buffer is higher than the temperature of the precursor source bottle. to .

5. The quantitative precursor supply system for atomic layer deposition according to claim 1, characterized in that, The dose of the gaseous precursor entering the dose buffer during the filling cycle is determined by the target pressure value, the volume of the dose buffer, and the temperature.

6. The quantitative precursor supply system for atomic layer deposition according to claim 1, characterized in that, The controller is also configured to: calculate the pressure rise slope within the dose buffer based on pressure changes fed back by the pressure monitoring component during the filling cycle. When the pressure rise slope When the temperature is below a preset threshold, the opening time of the first control valve is automatically extended, or the heating temperature of the precursor source bottle is increased.

7. The quantitative precursor supply system for atomic layer deposition according to claim 1, characterized in that, The dose buffer has a variable volume structure, which is a bellows structure.

8. The quantitative precursor supply system for atomic layer deposition according to claim 1, characterized in that, The second control valve is a pulse valve specifically designed for atomic layer deposition.

9. A method for quantitative supply control of precursors for atomic layer deposition, characterized in that, The method of using the quantitative precursor supply system for atomic layer deposition according to any one of claims 1-8 includes: Control the at least one set of buffer units to perform filling and releasing cycles; The filling cycle includes: opening the first control valve to allow the gaseous precursor to enter the dose buffer from the precursor source bottle, and using a pressure monitoring component to detect the pressure in the dose buffer in real time. When the pressure reaches a preset target pressure value, the first control valve is closed. The release cycle includes: opening the second control valve to release the quantified gaseous precursor in the dose buffer into the reaction chamber.

10. The method for controlling the quantitative supply of precursors according to claim 9, characterized in that, The buffer units are arranged in at least two sets in parallel; the method further includes: controlling the at least two sets of buffer units to alternately execute the filling cycle and the releasing cycle, wherein when the first set of buffer units executes the releasing cycle, the second set of buffer units is simultaneously controlled to execute the filling cycle.

11. The method for controlling the quantitative supply of precursors according to claim 9, characterized in that, Also includes: The precursor source bottle, the dose buffer, and the connecting pipeline are heated in segments, and a temperature gradient is maintained so that the temperature of the dose buffer is higher than the temperature of the precursor source bottle, and the temperature of the connecting pipeline between the second control valve and the reaction chamber is higher than the temperature of the dose buffer.

12. The precursor quantitative supply control method according to claim 9, characterized in that, Also includes: During the filling cycle, the pressure rise slope within the dose buffer is calculated based on the pressure changes fed back by the pressure monitoring component. When the pressure rise slope When the temperature is below a preset threshold, the opening time of the first control valve is automatically extended, or the heating temperature of the precursor source bottle is increased.

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