Process liquid supply system

Abstract

A process liquid supply system is provided. The process liquid supply system includes a first tank for storing a process liquid, a second tank connected to the first tank for receiving and storing the process liquid from the first tank, a first line connecting the first tank and a nozzle, a second line connecting the second tank and the nozzle, a first valve disposed on the first line, and a second valve disposed on the second line. The first valve and the second valve are selectively opened to supply the process liquid from the first tank or the second tank to a substrate surface through the nozzle.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing, and more particularly to a process liquid supply system. Background Technology

[0002] In today's advanced semiconductor processes, thin metal films (such as copper films) are widely used in conductive layers and multilayer interconnect structures inside chips. To ensure that components have good electrical performance and mechanical stability, the etching process must have high-precision material removal capabilities while also ensuring surface cleanliness to avoid micro-contamination or residues affecting subsequent processes.

[0003] Traditional etching processes often utilize recycled solutions to reduce material costs and minimize chemical waste. However, as the etching reaction continues, a large amount of target metal ions (such as copper ions) and other byproducts gradually accumulate in the solution. If these impurities are not removed promptly, they will cause contamination, uneven corrosion, and metal residue on the wafer surface, leading to process defects such as inconsistent etching depth and pattern deformation. These defects not only reduce yield and process stability but may also induce reliability issues such as electrical anomalies or metal diffusion in subsequent processes, even resulting in the scrapping of an entire batch of wafers. Although some current processes have adopted fixed-cycle solution replacement (e.g., based on the number of wafers processed or the number of operating hours), this approach cannot reflect the actual chemical reaction status and the degree of solution degradation in real time. This can easily lead to premature replacement, resulting in resource waste, or delayed replacement, causing process control issues.

[0004] In view of this, it is necessary to provide a process liquid supply system to solve the above-mentioned technical problems. Utility Model Content

[0005] To address the problems of the prior art, the purpose of this application is to provide a process liquid supply system that can avoid wafer defects and process instability caused by chemical aging or over-etching.

[0006] In a first aspect, this application provides a process liquid supply system suitable for a substrate processing apparatus, the substrate processing apparatus comprising: a rotary table for carrying a substrate; a nozzle disposed above the rotary table; and a recovery ring disposed around the rotary table, wherein the process liquid supply system comprises: a first tank for storing process liquid; a second tank connected to the first tank for receiving and storing the process liquid from the first tank; a first pipeline connecting the first tank and the nozzle; a second pipeline connecting the second tank and the nozzle; a first valve disposed on the first pipeline; and a second valve disposed on the second pipeline, wherein one of the first valve and the second valve is opened to supply the process liquid from the first tank or the second tank to the substrate surface through the nozzle.

[0007] In some embodiments, the process liquid supply system further includes: a third pipeline connecting the recovery ring and the second tank; and a third valve disposed on the third pipeline, wherein the third valve opens synchronously with the second valve, so that the process liquid is supplied from the second tank to the substrate surface through the nozzle, recovered by the recovery ring, and transported back to the second tank through the third pipeline.

[0008] In some embodiments, the process liquid supply system further includes: a concentration analyzer; a fourth pipeline connecting the recovery ring and the concentration analyzer; and a fourth valve disposed on the fourth pipeline, wherein the fourth valve opens synchronously when the first valve opens, so that the process liquid is supplied from the first tank to the substrate surface through the nozzle, recovered by the recovery ring, and transported to the concentration analyzer through the fourth pipeline.

[0009] In some embodiments, the process liquid supply system further includes a heater disposed in the first tank for heating the process liquid in the first tank to a specific temperature.

[0010] Compared to previous technologies, this application provides a process liquid supply system that offers an innovative solution for the chemical solutions used in metal thin film etching processes, featuring real-time concentration monitoring and reaction endpoint determination mechanisms. By storing new and recycled solutions in separate tanks, using them in stages, and constructing a closed-loop circulation system with a concentration analyzer, changes in metal ion concentration can be dynamically detected, the etching endpoint can be accurately determined, and the host computer can automatically control the parameters, effectively preventing wafer defects and process instability caused by chemical aging or over-etching. Attached Figure Description

[0011] The following detailed description of the specific embodiments of this application, in conjunction with the accompanying drawings, will make the technical solution and other beneficial effects of this application readily apparent.

[0012] Figure 1 This diagram shows a process liquid supply system according to an embodiment of the present application.

[0013] Figure 2 This shows a graph illustrating the change in metal ion concentration during the etching reaction. Detailed Implementation

[0014] The technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0015] In semiconductor manufacturing, etching is a critical step affecting process yield and final product quality. Even minor variations can have a cascading effect on subsequent steps, impacting overall yield and reliability. Traditional etching techniques, to reduce costs, typically employ solution recycling and reuse. However, as the reaction continues, a large amount of target metal ions (such as copper ions) and other byproducts gradually accumulate in the solution. If these impurities are not removed in time, they can easily cause wafer surface contamination, unstable etching depth and uniformity, and even metal residue—process defects. These defects not only damage the physical and electrical quality of the wafer itself but also negatively impact downstream processes, potentially leading to the scrapping of an entire batch of wafers and significant cost losses. Although some current processes have adopted fixed-cycle solution replacement strategies, such as determining the replacement time based on the number of etched wafers, these approaches still cannot reflect the actual reaction status of the solution in real time, nor can they dynamically adjust to changes in copper ion concentration. The lack of precise and predictable control means means that etching stability and reproducibility cannot be adequately guaranteed. In view of the problem of surface defects caused by the deterioration of the chemical solution in the prior art, this application proposes an innovative process liquid supply system and its control method, which aims to solve this technical bottleneck, as detailed below.

[0016] Please refer to Figure 1 This diagram illustrates a process liquid supply system according to an embodiment of this application. The process liquid supply system proposed in this application is suitable for use in conjunction with a substrate processing apparatus to jointly complete the etching process of semiconductor wafers, and the two have a synergistic relationship in structure and function. The substrate processing apparatus mainly includes a rotating stage 21 located in the center, a nozzle 22 disposed above the rotating stage 21, and a recovery ring 23 disposed around the rotating stage 21. The rotating stage 21 carries the substrate 24 to be processed and can rotate around its central axis to facilitate uniform chemical etching. It may also be equipped with a vacuum adsorption module or a mechanical clamping mechanism to fix the substrate 24 in a predetermined position, ensuring process stability and accuracy. The nozzle 22 is located above the rotating stage 21 and supplies process liquid for spraying. Its lower surface corresponds to the surface of the substrate 24, used to uniformly supply the process liquid to the surface of the substrate 24 to perform the etching reaction. The process liquid supply system 10 is connected to the nozzle 22 via pipelines and is configured to store, transport, and switch process liquids from different sources, achieving multi-stage, controllable liquid supply. Its specific structure and control method will be detailed in subsequent paragraphs. The recovery ring 23 is positioned around the rotary table 21 to receive process liquid flowing from the substrate surface, preventing liquid splashing and contamination of the machine's interior, and serves as the front-end structure for subsequent liquid recovery and concentration management mechanisms. Through the functional coordination and system integration of the above components, the device of this application achieves a stable, precise, and highly efficient etching process.

[0017] like Figure 1 As shown, the process liquid supply system 10 mainly includes a first tank 11, a second tank 12, a concentration analyzer 13, a main unit 14, and multiple pipelines and corresponding valves connecting each part, including first pipeline P1 to fifth pipeline P5 and first valve V1 to fifth valve V5. The first tank 11 is used to receive and store brand-new, unused process liquid supplied by the plant-side process liquid supply equipment, serving as the main source of high-purity liquid in the system. In some embodiments, a heater (not shown in the figure) is further provided in the first tank 11 to heat the stored process liquid to a specific operating temperature, ensuring that the thermal conditions required for the reaction are maintained during the liquid supply process, which helps to improve etching efficiency and reaction stability.

[0018] like Figure 1 As shown, the first tank 11 and the second tank 12 are interconnected via a fifth conduit P5, and a fifth valve V5 is installed on the fifth conduit P5 to control the flow of liquid between the two tanks. During process operation, when the process liquid in the first tank 11 reaches a preset condition, such as being heated to a specified target temperature, the fifth valve V5 is opened, allowing the process liquid in the first tank 11 to be smoothly transported to the second tank 12 through the fifth conduit P5. Therefore, the main function of the second tank 12 is to receive and store the heated process liquid from the first tank 11 for use in subsequent liquid supply stages. Through this structural design, not only can the process liquid supplied to the substrate surface be maintained at the optimal reaction conditions, but the process instability problems that may be caused by the liquid not reaching the required temperature directly participating in the etching reaction can also be avoided, thereby enhancing the overall operating efficiency and process reliability of the system.

[0019] like Figure 1 As shown, the first conduit P1 connects the first tank 11 and the nozzle 22, and is equipped with a first valve V1 to control the liquid flow; the second conduit P2 connects the second tank 12 and the nozzle 22, and is also equipped with a second valve V2. During system operation, only one of the first valve V1 and the second valve V2 is opened to selectively supply process liquid from the first tank 11 or the second tank 12 to the nozzle 22, which is then sprayed onto the surface of the substrate 24 to perform an etching reaction. Specifically, the etching process of this application is divided into two stages, which are performed sequentially: the first stage prioritizes the use of the second valve V2 to perform the etching operation using the process liquid stored in the second tank 12; this stage is the main etching period, and its duration is longer than the subsequent stages; the second stage switches to opening the first valve V1 and closing the second valve V2, and instead uses the fresh process liquid stored in the first tank 11 for etching, which is used for touch-up etching and final fine etching. This phased liquid switching design effectively reduces the impact of liquid contamination during the main etching process on the final process, while maintaining cost-effectiveness, ensuring substrate surface cleanliness and etching uniformity, and further improving the overall process yield.

[0020] like Figure 1 As shown, the third pipe P3 connects the second tank 12 and the recovery ring 23, and a third valve V3 is installed on it to control the liquid flow. During system operation, when the second valve V2 opens and the process liquid is transported from the second tank 12 through the second pipe P2 to the nozzle 22 and sprayed onto the surface of the substrate 24, the third valve V3 also opens simultaneously. This allows the used process liquid to be collected through the recovery ring 23 and then returned to the second tank 12 through the third pipe P3. This stage is the first stage of the etching process described in this application, characterized by using the liquid stored in the second tank 12 to perform the main etching operation, and achieving the reuse of the solution through a closed-loop system formed by the second pipe P2 and the third pipe P3. This internal circulation mechanism can effectively extend the service life of the process liquid and reduce consumable costs.

[0021] like Figure 1 As shown, the fourth pipeline P4 connects the recovery ring 23 and the concentration analyzer 13, and is equipped with a fourth valve V4 to regulate the liquid flow. In the second stage of the etching process described in this application, when the first valve V1 is opened and the fresh process liquid stored in the first tank 11 is supplied to the surface of the substrate 24 through the nozzle 22, the fourth valve V4 is also opened, allowing the sprayed liquid to be recovered through the recovery ring 23 and further guided to the concentration analyzer 13 for analysis through the fourth pipeline P4. This stage is the final fine etching stage, characterized by the elimination of the use of recycled liquid for circulation, instead using fresh liquid for fine etching, and real-time monitoring of changes in metal ion concentration to determine whether the etching reaction is complete.

[0022] It should be understood that in the first stage of the etching process, the system uses recycled process liquid for etching. This liquid contains a certain amount of metal ions. When it is sprayed onto the surface of substrate 24, some of these metal ions adhere to the substrate 24, causing contamination and potential defects. To solve this problem, in the second stage of the etching process, a completely new and unused process liquid is used to spray the substrate 24. This effectively removes the metal ions remaining on the substrate 24 from the first stage, achieving a re-cleaning effect on the surface of substrate 24, thereby improving the overall process quality and reliability.

[0023] In this application, when the concentration analyzer 13 detects that the metal ion concentration has dropped to a preset endpoint value, the host 14 controls the first valve V1 to close and moves the nozzle 22 away from the substrate 24, thereby terminating the etching reaction. This preset endpoint value is determined based on experimental data and corresponds to specific etching depths or processing requirements, ensuring that the etching process is neither over-etched nor under-etched, further improving accuracy and reliability.

[0024] Please refer to Figure 2The graph displays the change in metal ion concentration during the etching reaction, where the X-axis represents the etching reaction time t, and the Y-axis represents the metal ion concentration value M detected in real time by the concentration analyzer 13. While the etching reaction is in progress, the metal ions released during the reaction maintain the concentration at a high level; however, as etching nears completion and the metal material to be etched approaches depletion, the concentration drops sharply. This sharp drop point is the key basis for determining the etching endpoint, and the host 14 can immediately shut off the liquid supply and end the process before this point. It should be understood that the preset endpoint value ΔM can be a fixed concentration value or a concentration range to adapt to the flexible requirements of different chip designs and etching conditions. Through the real-time analysis and dynamic control mechanism disclosed in this application, the accuracy and yield of the etching process can be effectively improved, while avoiding product defects caused by over-etching.

[0025] This application also provides a control method for a process liquid supply system, wherein the structure of the process liquid supply system and the applicable substrate processing apparatus is as described above and will not be repeated here. It should be understood that the host computer 14 of this application is communicatively connected to the process liquid supply system 10 and the various components of the substrate processing apparatus, and includes an electrically connected processor and memory. The processor and memory of the host computer are mounted on a circuit board. The memory is configured to store executable program code. The processor reads the executable program code stored in the memory and runs the program corresponding to this executable program code to execute the control method for the process liquid supply system of this application.

[0026] In this embodiment, the processor is typically configured to control the overall operation of the host. The processor may include one or more processors to execute instructions that perform actions in all or part of the steps of the operation of the process fluid supply system 10 described above. Furthermore, the processor may include one or more modules that facilitate interaction between the processor and other components. For example, the processor may include a communication module to facilitate interaction between communication components and the processor. The memory is configured to store various types of data to support the operation of the host. Examples of such data include instructions for any application or method operating on the host. The memory may be implemented using any type of volatile or non-volatile memory device or a combination thereof. Power supply circuitry supplies power to various components of the host. The power supply circuitry may include a power management system, one or more power supplies, and any other components associated with the generation, management, and distribution of power to the host. In an exemplary embodiment, the host 14 may be implemented as a standalone terminal device or as an electronic component such as a controller or microcontroller integrated into the process fluid supply system 10.

[0027] The control method of the process liquid supply system disclosed in this application can be mainly divided into three stages: process liquid preparation stage, first stage etching operation and second stage etching operation. It follows a specific timing sequence and control logic to achieve a high-precision and repeatable semiconductor etching process.

[0028] In the first stage, the system prepares the process fluid. For example... Figure 1 As shown, initially, all valves remain closed to ensure system stability and prevent unexpected liquid flow. New, unused process liquid supplied from the plant's process liquid supply equipment is guided to the first tank 11 for storage, and can be selectively heated to a preset operating temperature by a heater (not shown) located in the first tank 11. When the liquid in the first tank 11 reaches the preset conditions, such as the target temperature, the main unit 14 controls the opening of the fifth valve V5, allowing the liquid to be transferred to the second tank 12 through the fifth pipeline P5, completing the liquid preparation and tank separation operation, ensuring the stability of the liquid supply and the reliability of the process in the subsequent etching stage. After the transfer is completed, the system can also inject a new batch of process liquid into the first tank 11 and perform heating operations to maintain the continuity of the system's liquid supply and the stability of the process.

[0029] The first stage of the etching process then begins. This stage is the main etching period, lasting longer than the second stage, and its purpose is to remove most of the target metal material. During this stage, the host 14 controls the opening of the second valve V2 and the third valve V3, while all other valves remain closed. The process liquid is transported from the second tank 12 to the nozzle 22 through the second pipeline P2, and is evenly sprayed onto the surface of the substrate 24 mounted on the rotary table 21 for etching. The used liquid is collected through the recovery ring 23 and then returned to the second tank 12 through the third pipeline P3, forming an internal circulation loop that allows the liquid to be reused, reducing consumable consumption and costs while maintaining a stable etching environment.

[0030] After the first stage etching is completed, the system enters the second stage etching, which is mainly used for touch-up etching and final fine etching, focusing on etching uniformity and the accuracy of endpoint control. In this stage, the host 14 controls the opening of the first valve V1 and the fourth valve V4, while the remaining valves are closed. At this time, the fresh process liquid stored in the first tank 11 is sprayed onto the substrate surface through the first pipeline P1 and nozzle 22, collected by the recovery ring 23, and guided by the fourth pipeline P4 to the concentration analyzer 13 for real-time detection of metal ion concentration. When the concentration analyzer 13 detects that the metal ion concentration has dropped to a preset endpoint value, which is a concentration range preset based on experimental data and different etching requirements, the host 14 automatically closes the first valve V1 and moves the nozzle 22 away from the substrate 24, thereby terminating the overall etching reaction. This automatic control mechanism not only improves the accuracy of etching depth and endpoint control but also avoids chip defects caused by over-etching or under-etching, effectively enhancing process stability and product yield.

[0031] It should be understood that in the first stage of the etching process, the system uses recycled process liquid for etching. This liquid contains a certain amount of metal ions. When it is sprayed onto the surface of substrate 24, some of these metal ions adhere to the substrate 24, causing contamination and potential defects. To solve this problem, in the second stage of the etching process, a completely new and unused process liquid is used to spray the substrate 24. This effectively removes the metal ions remaining on the substrate 24 from the first stage, achieving a re-cleaning effect on the surface of substrate 24, thereby improving the overall process quality and reliability.

[0032] In summary, the process liquid supply system provided in this application offers an innovative solution specifically for the chemical solutions used in metal thin film etching processes, featuring real-time concentration monitoring and reaction endpoint determination mechanisms. By storing new and recycled solutions in separate tanks, using them in stages, and constructing a closed-loop circulation system with a concentration analyzer, changes in metal ion concentration can be dynamically detected, the etching endpoint can be accurately determined, and the host computer can automatically control the parameters, effectively preventing wafer defects and process instability caused by chemical aging or over-etching. This system not only improves the consistency and reproducibility of the etching process but also significantly improves the control accuracy of wafer surface cleanliness and etching contours. Overall, it can effectively improve the yield and production efficiency in chip manufacturing processes, and has extremely high practicality and industrial value for applications with high-end processes and high reliability requirements.

[0033] The foregoing has provided a detailed description of a process liquid supply system according to the embodiments of this application. Specific embodiments have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are merely for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A process liquid supply system, suitable for a substrate processing apparatus, the substrate processing apparatus comprising: A rotating stage for supporting a substrate; a nozzle disposed above the rotating stage; and a recovery ring disposed around the rotary table, characterized in that the process liquid supply system comprises: The first tank is used to store process liquids; The second tank, connected to the first tank, is used to receive and store the process liquid from the first tank; A first pipeline connects the first groove and the nozzle; The second pipeline connects the second groove and the nozzle; The first valve is installed on the first pipeline; A second valve is disposed on the second pipeline, wherein one of the first valve and the second valve is opened to supply the process liquid from the first tank or the second tank to the substrate surface through the nozzle.

2. The process liquid supply system as described in claim 1, characterized in that, The process liquid supply system also includes: The third pipeline connects the recycling ring and the second tank; A third valve is disposed on the third pipeline, wherein the third valve opens synchronously with the second valve, so that the process liquid is supplied from the second tank to the substrate surface through the nozzle, then recovered by the recovery ring, and transported back to the second tank through the third pipeline.

3. The process liquid supply system as described in claim 1, characterized in that, The process liquid supply system also includes: Concentration analyzer; The fourth pipeline connects the recovery loop and the concentration analyzer; A fourth valve is provided on the fourth pipeline, wherein the fourth valve opens synchronously when the first valve opens, so that the process liquid is supplied from the first tank to the substrate surface through the nozzle, then recovered by the recovery ring, and transported to the concentration analyzer through the fourth pipeline.

4. The process liquid supply system as described in claim 1, characterized in that, The process liquid supply system further includes a heater disposed in the first tank for heating the process liquid in the first tank to a specific temperature.

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