A focus ring and focus ring module

Abstract

The utility model relates to the technical fields related to semiconductor processing especially, and it is a kind of focusing ring and focusing ring module.The focusing ring of the utility model is provided with gas passage in the focusing ring, the gas passage has gas inlet and gas outlet, the gas inlet is used to pass into inert gas and / or reaction gas, the gas outlet is towards the position of wafer on the upper of the placement table, to pass into inert gas and / or reaction gas at wafer edge.This application can directly influence the etching environment of edge area by setting gas passage in focusing ring and using gas supply assembly to accurately supply inert gas and / or reaction gas to wafer edge area, to realize the dynamic control to wafer edge etching rate.

Description

Technical Field

[0001] This utility model relates to the technical field of semiconductor processing, and in particular to a focusing ring and a focusing ring module. Background Technology

[0002] Etching is a critical step in semiconductor manufacturing, and its uniformity directly affects device performance. The focusing ring, a core component of etching equipment, is used to improve the etching uniformity at the wafer edges or perimeter, hold the wafer in place to maintain plasma density, and prevent contamination of the wafer sides.

[0003] However, due to the continuous exposure to high temperatures, high pressures, and highly corrosive gases during the etching process, the focusing ring material undergoes physical wear and chemical corrosion, leading to a gradual decrease in its thickness. This thickness variation affects the etching rate at the wafer edges, causing abnormal edge etching rates and consequently deteriorating the uniformity of the wafer surface etching.

[0004] Although the focusing ring retains its mechanical support function until it is thinned to the point of complete failure, its ability to control plasma distribution is significantly reduced, and it typically needs to be replaced after a period of use. However, such frequent replacements not only increase production costs but also affect production line efficiency due to equipment downtime. Utility Model Content

[0005] The purpose of this invention is to provide a focusing ring and a focusing ring module, so as to improve the service life of the focusing ring and the uniformity of wafer etching.

[0006] To solve the above-mentioned technical problems, this utility model provides a focusing ring and a focusing ring module.

[0007] The focusing ring of this invention has a gas channel with an inlet and an outlet. The inlet is used to introduce inert gas and / or reactive gas, and the outlet is oriented towards the position of the wafer above the placement stage to introduce inert gas and / or reactive gas at the edge of the wafer.

[0008] Furthermore, the gas channel includes multiple branch channels, and there are multiple gas outlets, which are evenly spaced along the circumference, with each branch channel corresponding to a gas outlet.

[0009] Furthermore, there is one air inlet, and multiple branch channels share one air outlet, with the stroke between the multiple air outlets and the air inlet being equal.

[0010] Furthermore, there are multiple air inlets, and the multiple branch channels are divided into multiple groups, with each group of branch channels including at least one branch channel and sharing one air outlet.

[0011] Furthermore, the focusing ring includes a first ring plate and a second ring plate. A first channel groove is provided on the lower bottom surface of the first ring plate, and a second channel groove is provided on the upper surface of the second ring plate. The first ring plate and the second ring plate are fitted together so that the first channel groove and the second channel groove form the gas channel.

[0012] Furthermore, the air outlet is provided with a flared structure.

[0013] Furthermore, the flaring structure is a trumpet-shaped flaring or a conical flaring.

[0014] This application also provides a focusing ring module, including a gas supply assembly and a focusing ring as described in any of the above technical solutions;

[0015] The gas supply assembly is connected to the air inlet and is used to supply inert gas and / or reactive gas to the air inlet to regulate the etching rate at the wafer edge.

[0016] Furthermore, the gas supply assembly includes an inert gas branch, a reactive gas branch, and a heating element. The inert gas branch is used to introduce inert gas into the inlet, the reactive gas branch is used to introduce reactive gas into the inlet, and the heating element is used to heat the inert gas and / or the reactive gas.

[0017] Furthermore, both the inert gas branch and the reactant gas branch are equipped with pressure regulating valves, flow meters, and inlet valves.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects:

[0019] This application achieves dynamic control of the wafer edge etching rate by setting a gas channel in the focusing ring and precisely supplying inert and / or reactive gases to the wafer edge region using a gas supply component. This directly influences the etching environment of the edge region. This design overcomes the limitations of traditional focusing rings that rely solely on physical properties to control edge etching, providing a more flexible and precise etching control method. This application can precisely control the etching conditions of the edge region without affecting the etching of the wafer center region. This local control method not only improves etching uniformity but also extends the lifespan of the focusing ring and reduces frequent replacements due to edge effects. Attached Figure Description

[0020] Figure 1 This is a longitudinal cross-sectional view of the focusing ring of the focusing ring module of this utility model;

[0021] Figure 2 for Figure 1 A cross-sectional view of the focusing ring of the focusing ring module in the image;

[0022] Figure 3 This is a schematic diagram of the structure of one embodiment of the focusing ring module of this utility model when used in conjunction with an electrostatic chuck;

[0023] Figure 4 for Figure 3 A schematic diagram showing the connection between the gas supply component and the focusing ring in the focusing ring module.

[0024] Figure label:

[0025] 1. Electrostatic chuck;

[0026] 2. Focusing ring; 3. Wafer; 4. Gas channel; 5. Gas inlet; 6. Gas outlet;

[0027] 7. First sealing ring; 8. Second sealing ring; 9. First air blowing line; 10. First area; 11. Second air blowing line; 12. Second area; 13. Branch channel. Detailed Implementation

[0028] The focusing ring and focusing ring module of this utility model will now be described with reference to the schematic diagrams, which illustrate preferred embodiments of this utility model. It should be understood that those skilled in the art can modify the utility model described herein while still achieving its advantageous effects. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit this utility model.

[0029] The serial numbers assigned to components in this document, such as "first" and "second," are used only to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages). In the description of this utility model, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0030] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0031] The present invention will be described in more detail below by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0032] The inventors discovered that in semiconductor etching processes, wafers are placed on electrostatic chucks surrounded by focusing rings. When the etching process begins, insufficient temperature control at the edges can cause a significant difference in etching rate between these areas and the center of the wafer, thus affecting etching uniformity. Furthermore, due to the lack of precise edge etching rate control, engineers often have to frequently replace the focusing rings, even if these rings may still have some usability.

[0033] This application proposes a focusing ring module, such as Figure 1 , Figure 2 and Figure 3 As shown, the focusing ring module includes a gas supply assembly and a focusing ring 2.

[0034] The focusing ring 2 is provided with a gas channel 4, which has an inlet 5 and an outlet 6. The inlet 5 is used to introduce inert gas and / or reactive gas, and the outlet 6 is oriented towards the position of the wafer 3 above the placement stage so as to introduce inert gas and / or reactive gas at the edge of the wafer 3.

[0035] The gas supply assembly is connected to the air inlet 5 and is used to supply inert gas and / or reactive gas to the air inlet 5 to regulate the etching rate at the edge of the wafer 3.

[0036] The focusing ring module of this application is used in conjunction with the electrostatic chuck 1. Specifically, the electrostatic chuck 1 has a placement stage for placing the wafer 3; the focusing ring 2 is disposed on the electrostatic chuck 1 and arranged around the placement stage.

[0037] The electrostatic chuck 1 is a device used to fix the wafer 3, and can be implemented using a planar structure made of ceramic material. The focusing ring 2 is a ring-shaped structure surrounding the electrostatic chuck 1, and can be made of silicon material, with a shape matching the outer contour of the electrostatic chuck 1. The gas channel 4 is a passage for gas flow inside the focusing ring 2, including an inlet 5 and an outlet 6. The inlet 5 is located on the outside or bottom of the focusing ring 2 and is used to connect to the gas supply assembly. The outlet 6 faces the wafer 3 above the placement stage, ensuring that the gas can directly act on the edge area of ​​the wafer 3; this can be achieved by internal slotting or drilling. The gas supply assembly is connected to the inlet 5 of the focusing ring 2. The device for providing inert and reactive gases can be implemented using gas tanks, pipelines, and control valves. By precisely controlling the type, flow rate, pressure, and temperature of the gas, dynamic adjustment of the etching environment at the edge of the wafer 3 can be achieved.

[0038] This application achieves dynamic control of the etching rate at the edge of wafer 3 by setting a gas channel 4 in the focusing ring 2 and precisely supplying inert gas and / or reactive gas to the edge region of wafer 3 using a gas supply component. This directly affects the etching environment of the edge region. This design overcomes the limitations of traditional focusing ring 2 which relies solely on physical properties to control edge etching, providing a more flexible and precise etching control method. This application can precisely control the etching conditions in the edge region without affecting the etching of the central region of wafer 3. This local control method not only improves etching uniformity but also extends the lifespan of the focusing ring 2 and reduces frequent replacements due to edge effects.

[0039] In practice, when the etching rate at the wafer edge is detected to be too fast, at least one of the following measures can be taken to reduce the etching rate in the edge region: increasing the inert gas flow rate, decreasing the reactive gas flow rate, or decreasing the temperature of both the inert and reactive gases. Conversely, when the edge etching rate is too slow, at least one of the following measures can be taken to increase the etching rate: decreasing the inert gas flow rate, increasing the reactive gas flow rate, or increasing the temperature of both the inert and reactive gases. This method allows for rapid adjustments based on real-time monitoring results, ensuring the uniformity of the etching process.

[0040] In some embodiments, in order to control the temperature of the wafer 3, a first sealing ring 7 and a second sealing ring 8 are provided on the wafer 3 placement stage of the electrostatic chuck 1, and the diameter of the first sealing ring 7 is smaller than the diameter of the second sealing ring 8. The wafer 3 is placed on the first sealing ring 7 and the second sealing ring 8. The electrostatic chuck 1 is also provided with a first air blowing pipe 9 and a second air blowing pipe 11. The first air blowing pipe 9 is used to blow gas into the first area 10 formed by the first sealing ring 7, and the second air blowing pipe 11 is used to blow gas into the second area 12 formed by the second sealing ring 8. The gas blown by the first air blowing pipe 9 and the second air blowing pipe 11 is used to control the temperature of the wafer 3. Depending on the process requirements, it can be an inert gas used to heat the wafer 3 or an inert gas used to cool the wafer 3. The inert gas can be argon, helium or nitrogen.

[0041] In some embodiments, in order to make the gas distribution in the gas channel 4 more uniform, the gas channel 4 includes multiple branch channels 13, and there are multiple air outlets 6, which are evenly spaced along the circumference of the placement platform. The branch channels 13 correspond one-to-one with the air outlets 6.

[0042] The multiple gas outlets 6 increase the distribution points of gas output, helping to more evenly cover the edge area of ​​wafer 3. The gas outlets 6 are evenly spaced along the circumference of the placement stage, ensuring uniform gas distribution at the edge of wafer 3 and avoiding insufficient or excessive gas supply in certain areas. This uniform distribution design effectively reduces etching non-uniformity in the edge area of ​​wafer 3, improving the accuracy and consistency of the etching process.

[0043] In some embodiments, there is one air inlet 5, and multiple branch channels 13 share one air outlet 6, with the travel distance between the multiple air outlets 6 and the air inlet 5 being equal.

[0044] Since the travel distance between all outlets 6 and inlets 5 is equal, the resistance encountered by the gas during flow is also essentially the same. This ensures that the gas can be evenly distributed to each outlet 6, thereby forming a uniform gas distribution at the edge of wafer 3. A uniform gas distribution is crucial for controlling the etching rate at the edge of wafer 3 and can effectively improve the etching uniformity at the edge of wafer 3.

[0045] like Figure 2 As shown, taking the focusing ring 2 with four air outlets 6 as an example, the air outlets 6 extend into the focusing ring 2 and then split into two, then into four, thus forming four branch channels 13 with equal strokes. In other embodiments, other numbers of branch channels 13 can be set according to needs, such as 8, 16, or 32.

[0046] In other embodiments, there are multiple air inlets 5, and multiple branch channels 13 are divided into multiple groups, each group of branch channels 13 including at least one branch channel 13 and sharing a common air outlet 6.

[0047] Specifically, the design of multiple air inlets 5 provides more entry points for gas supply. Each air inlet 5 can be controlled independently, thereby adjusting the amount and type of gas supplied according to the needs of different areas.

[0048] Furthermore, dividing the branch channels 13 into multiple groups, each sharing a single outlet 6, enables precise control of gas distribution. This layout allows for more accurate adjustment of the gas supply to different regions at the edge of wafer 3. For example, the etching rate can be balanced by adjusting the gas flow rate in the corresponding group of branch channels 13, based on the etching conditions at different locations at the edge of wafer 3.

[0049] In a preferred embodiment, there can be multiple gas supply assemblies, each corresponding to one air inlet 5. This configuration further enhances the ability to independently control each air inlet 5. Each gas supply assembly can independently adjust the gas type, flow rate, and temperature of its corresponding air inlet 5, thereby achieving finer etching control.

[0050] For example, in one specific embodiment, four air inlets 5 can be provided, located in the four quadrants of the focusing ring 2. Each air inlet 5 is connected to three branch channels 13, which are located in the same quadrant and each has an air outlet 6. Four sets of gas supply components are connected to the four air inlets 5 respectively. In actual operation, the etching rate can be balanced by adjusting the parameters of the corresponding gas supply components according to the etching conditions of different areas at the edge of the wafer 3.

[0051] Specifically, if the etching rate is found to be too high at the edge of a certain quadrant of wafer 3, the etching rate can be reduced by increasing the inert gas flow rate at the corresponding inlet 5 or decreasing the reactive gas flow rate. Alternatively, the temperature of the inert gas or reactive gas can be lowered. Conversely, if the etching rate is too low at the edge of a certain quadrant, the etching rate can be increased by increasing the reactive gas flow rate or decreasing the inert gas flow rate. Alternatively, the temperature of the inert gas or reactive gas can be increased. In this way, a more uniform etching effect can be achieved at the edge of wafer 3.

[0052] In one embodiment, such as Figure 4 As shown, the gas supply assembly includes an inert gas branch, a reactive gas branch, and a heating element. The inert gas branch is used to introduce inert gas into the inlet 5, the reactive gas branch is used to introduce reactive gas into the inlet 5, and the heating element is used to heat the inert gas and / or the reactive gas.

[0053] The inert gas branch can use various inert gases, such as argon, helium, or nitrogen. The reactive gas branch can select appropriate reactive gases based on the specific etching process, such as fluorine, chlorine, or other reactive gases. The heating element can be an electric heating wire, an infrared heating lamp, or other heating device.

[0054] The inert gas branch and the reactive gas branch can be controlled independently, and the etching rate can be affected by adjusting their respective flow rates, proportions, or temperatures. The heating element can heat both gases simultaneously or separately, thereby further influencing the etching rate through temperature control.

[0055] In some embodiments, in order to accurately control the inert gas and the reactant gas, a pressure regulating valve, a flow meter, and an inlet valve are provided on both the inert gas branch and the reactant gas branch.

[0056] Specifically, the pressure regulating valve dynamically adjusts the gas pressure according to the needs of different etching stages, ensuring that the gas enters the system at the optimal pressure. The flow meter monitors the gas flow rate in real time and feeds the data back to the control system, enabling the system to adjust the gas supply in a timely manner. The inlet valve can precisely control the opening and closing time of the gas, achieving precise timing control of the gas supply.

[0057] For example, in the inert gas branch, a precision pressure regulating valve can be used, with a pressure regulation range of 0-100 kPa and an accuracy of ±0.1 kPa. A mass flow meter can be selected, with a measurement range of 0-1000 sccm and an accuracy of ±1%. A fast-response solenoid valve can be selected for the inlet valve, with a response time of less than 50 ms. These parameters can be adjusted according to actual needs.

[0058] A similar configuration can be used in the reactant gas branch, but materials with stronger corrosion resistance should be selected based on the characteristics of the reactant gas. For example, an all-metal sealed type can be used for the pressure regulating valve, a corrosion-resistant mass flow meter can be used for the flow meter, and a solenoid valve with a corrosion-resistant coating can be used for the inlet valve.

[0059] By installing these control elements on two separate gas branches, operators can independently adjust the pressure, flow rate, and supply sequence of each gas. This design not only improves the controllability and precision of the etching process but also allows for flexible adjustment of gas supply parameters according to different etching requirements, contributing to improved etching uniformity and product quality.

[0060] As a preferred implementation, a predetermined gas supply formula can be set in the control system. For example, for a specific type of wafer 3 and etching process, the optimal flow rate ratio, pressure value, and supply sequence of inert gas and reactive gas can be preset. In actual operation, the operator only needs to select the appropriate formula, and the system will automatically adjust the various control components to achieve the optimal gas supply state. This not only simplifies the operation process but also improves production efficiency and consistency.

[0061] Furthermore, the technical solution of this application also helps to optimize gas utilization efficiency. By precisely controlling the gas supply, unnecessary gas waste can be reduced, thereby lowering production costs. For example, the gas supply quantity and timing can be precisely controlled according to actual needs, avoiding waste caused by excessive gas supply.

[0062] In one embodiment, in order to create the gas channel 4, the focusing ring 2 includes a first ring plate and a second ring plate. A first channel groove is provided on the lower bottom surface of the first ring plate, and a second channel groove is provided on the upper surface of the second ring plate. The first ring plate and the second ring plate are fitted together so that the first channel groove and the second channel groove form the gas channel 4.

[0063] Specifically, by dividing the focusing ring 2 into two ring plates and setting channel grooves on their respective surfaces, the complex gas channel 4 structure can be fabricated more easily. This design not only simplifies the manufacturing process but also improves the precision and consistency of the gas channel 4. When the two ring plates are bonded together, the formed gas channel 4 can supply gas more uniformly to the edge of the wafer 3, thereby more effectively controlling the etching rate.

[0064] Furthermore, this split design also facilitates the maintenance and replacement of the focusing ring 2. When cleaning or replacing the gas channel 4 is required, the two rings can be easily separated, the necessary operations performed, and then reassembled. This greatly improves the maintainability and service life of the equipment.

[0065] In a preferred embodiment, the first and second annular plates can be made of the same or different materials. For example, high-temperature resistant and corrosion-resistant ceramic materials or special alloy materials can be selected. The first and second channel grooves can be manufactured using precision machining techniques, such as CNC milling or laser etching, to ensure the accuracy and surface finish of the channels.

[0066] In practical applications, the first and second ring plates can be fixed by bolts or snap-fit ​​structures. To ensure airtightness, sealing rings or sealant can be applied to the contact surfaces of the two ring plates. The cross-section of the gas channel 4 can be designed as circular, elliptical, or other suitable shapes to optimize gas flow characteristics.

[0067] This design simplifies and enhances the manufacturing of gas channel 4. Only a shallow groove needs to be machined on each ring, significantly reducing manufacturing difficulty and cost compared to machining complex internal channels on the integral focusing ring 2. Furthermore, since the channel is composed of two rings, it is easier to inspect and clean, improving maintenance convenience.

[0068] In some embodiments, the air outlet 6 is provided with a flared structure. By gradually increasing the cross-sectional area of ​​the flow channel, the flared structure can reduce the gas flow velocity, changing the gas flow from concentrated jet to diffuse flow, avoiding concentrated airflow impacting a single point, thereby achieving a more uniform gas distribution.

[0069] Preferably, the flaring structure is a trumpet-shaped flare or a conical flare. In other embodiments, the flaring structure can also be other gradually expanding structures, such as a semi-ellipse.

[0070] This application also provides a focusing ring, the structure of which is the same as that of the focusing ring module in the first aspect embodiment described above, and will not be described again here.

[0071] Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of equivalent technology, this utility model also intends to include these modifications and variations.

Claims

1. A focusing ring, characterized in that, The focusing ring is provided with a gas channel, which has an inlet and an outlet. The inlet is used to introduce inert gas and / or reactive gas, and the outlet is oriented towards the position of the wafer above the placement stage to introduce inert gas and / or reactive gas at the edge of the wafer.

2. The focusing ring according to claim 1, characterized in that, The gas channel includes multiple branch channels, and there are multiple gas outlets, which are evenly spaced along the circumference. Each branch channel corresponds to a gas outlet.

3. The focusing ring according to claim 2, characterized in that, There is one air inlet, and multiple branch channels share one air outlet. The stroke between the multiple air outlets and the air inlet is equal.

4. The focusing ring according to claim 2, characterized in that, There are multiple air inlets, and the multiple branch channels are divided into multiple groups. Each group of branch channels includes at least one branch channel and shares one air outlet.

5. The focusing ring according to claim 1, characterized in that, The focusing ring includes a first ring plate and a second ring plate. A first channel groove is provided on the lower bottom surface of the first ring plate, and a second channel groove is provided on the upper surface of the second ring plate. The first ring plate and the second ring plate are fitted together so that the first channel groove and the second channel groove form the gas channel.

6. The focusing ring according to claim 1, characterized in that, The air outlet is provided with a flared structure.

7. The focusing ring according to claim 6, characterized in that, The flaring structure is either a trumpet-shaped flare or a conical flare.

8. A focusing ring module, characterized in that, Includes a gas supply assembly and a focusing ring as described in any one of claims 1 to 7; The gas supply assembly is connected to the air inlet and is used to supply inert gas and / or reactive gas to the air inlet to regulate the etching rate at the wafer edge.

9. The focusing ring module according to claim 8, characterized in that, The gas supply assembly includes an inert gas branch, a reactive gas branch, and a heating element. The inert gas branch is used to introduce inert gas into the inlet, the reactive gas branch is used to introduce reactive gas into the inlet, and the heating element is used to heat the inert gas and / or the reactive gas.

10. The focusing ring module according to claim 9, characterized in that, Both the inert gas branch and the reactant gas branch are equipped with pressure regulating valves, flow meters, and inlet valves.

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