Etching device
By setting up a cover and a gas distribution plate in the etching device, the temperature of the upper electrode can be quickly adjusted and stably controlled, which solves the problem of insufficient temperature control of the quartz upper electrode and improves the production efficiency and product consistency of the etching equipment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- BEIJING YANDONG MICROELECTRONICS TECH CO LTD
- Filing Date
- 2025-06-09
- Publication Date
- 2026-04-28
AI Technical Summary
Existing metal etching equipment suffers from insufficient temperature control capabilities on the quartz upper electrode, resulting in limited production capacity and inadequate process stability, which affects etching results and production quality.
By setting up a cover in the etching apparatus and supplying temperature-adjustable gas into it, rapid adjustment and precise and stable control of the upper electrode temperature can be achieved. Combined with a gas distribution plate and a temperature sensor, the airflow path and heat exchange effect are optimized to avoid abnormal etching parameters caused by temperature instability.
It improves the production efficiency and product consistency of etching equipment, avoids etching interruptions caused by temperature instability, enhances etching uniformity and precision, and significantly increases the equipment's capacity.
Smart Images
Figure CN224177312U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor manufacturing equipment technology, specifically providing an etching apparatus. Background Technology
[0002] Etching is a critical process that selectively removes unwanted material from the surface of a wafer using chemical or physical methods. In practical applications, the appropriate etching type and corresponding etching equipment must be selected based on the properties of the material being etched and the precision requirements of the process. For metal etching, the mainstream equipment currently employs inductively coupled plasma etching technology, and the upper electrode of its etching chamber is typically made of quartz.
[0003] However, existing plasma etching technology based on quartz top electrodes has significant shortcomings, primarily in temperature control: First, preheating is required before etching to ensure a stable etching rate. Preheating is typically achieved through direct contact heating of the RF coil above the top electrode to reach a predetermined temperature, but this process is time-consuming. Second, the continuous accumulation of heat from the RF coil during etching causes the top electrode temperature to rise continuously. When the top electrode temperature exceeds the safety limit, the etching equipment is forced to stop. Due to the characteristics of quartz, effective water cooling devices cannot be installed for active temperature control; production can only resume after the quartz material naturally cools to a suitable temperature. This passive cooling method is extremely inefficient, hindering capacity increases. Furthermore, the continuous rise in top electrode temperature during etching leads to an unstable thermal environment in the etching chamber, causing key parameters such as etching uniformity and etching depth to deviate from design requirements, affecting the etching effect. More seriously, frequent automatic interruptions not only disrupt the internal process environment of the etching chamber but may also lead to etching accuracy deviations, causing abnormal product parameters and even scrapping of work-in-process, posing a dual challenge to production quality and cost control.
[0004] Therefore, a technical solution is needed to address the above problems. Utility Model Content
[0005] This application aims to solve the aforementioned technical problems, namely, to address the limitations in production capacity and process stability caused by insufficient temperature control capability of the quartz upper electrode in existing metal etching equipment.
[0006] In a first aspect, this application provides an etching apparatus, comprising: a vacuum chamber for accommodating a workpiece to be etched, the vacuum chamber having opposing first and second electrodes, a portion of the first electrode located within the vacuum chamber, and a radio frequency generator disposed on the portion of the first electrode facing away from the vacuum chamber; and a cover surrounding the outside of the first electrode such that another portion of the first electrode and the radio frequency generator are located within a closed space formed by the cover; wherein the cover has an inlet and an outlet communicating with the closed space, gas is circulated into the closed space through the inlet for heat exchange with the radio frequency generator and the first electrode, and the heat-exchanged gas is discharged from the outlet.
[0007] Optionally, the etching apparatus further includes: a gas distribution plate disposed in a closed space, which divides the closed space into a first chamber and a second chamber, with an air inlet communicating with the first chamber and an exhaust port communicating with the second chamber; a radio frequency generator and another part of the first electrode are both located in the second chamber; and the gas distribution plate is provided with a plurality of through holes communicating with the first chamber and the second chamber.
[0008] Optionally, multiple through holes are arranged in an array on the gas distribution disk.
[0009] Optionally, the orthogonal projection of the gas distribution disk onto the first electrode covers the first electrode.
[0010] Optionally, the orthographic projection of the gas distribution disk onto the RF generator covers the RF generator.
[0011] Optionally, a flow guide is provided on the surface of the gas distribution disk facing the second chamber, and the flow guide extends radially from the edge of the through hole toward the second chamber.
[0012] Optionally, the radial cross-section of the through hole increases from the first chamber to the second chamber.
[0013] Optionally, the gas distribution disc is fitted to the inner peripheral wall of the enclosure.
[0014] Optionally, multiple exhaust ports are provided, and the multiple exhaust ports are spaced apart along the circumference of the cover.
[0015] Optionally, the aforementioned etching apparatus further includes: an air supply line disposed at the air inlet, and the air supply line is connected to a heating module.
[0016] Optionally, the etching apparatus further includes: a temperature sensor located in an enclosed space and close to the first electrode; a control valve connected to the gas supply line; and a controller that is communicatively connected to both the temperature sensor and the control valve, wherein the controller controls the opening degree of the control valve based on the temperature sensor's detection value.
[0017] By adopting the above technical solution, the etching apparatus provided in this application can achieve rapid adjustment and precise and stable control of the upper electrode temperature by supplying gas into the enclosure. In this way, the preheating efficiency of the upper electrode can be improved during the preheating stage before etching, thereby improving production efficiency. During the etching process, the gas introduced can work with the radio frequency coil to precisely control the temperature of the upper electrode, avoiding problems such as abnormal etching parameters or even automatic shutdown of the etching equipment caused by unstable temperature of the upper electrode or even exceeding the upper limit. This can improve product consistency and effectively maximize production capacity. Attached Figure Description
[0018] The preferred embodiments of this application are described below with reference to the accompanying drawings, in which:
[0019] Figure 1 This is a partial structural schematic diagram of an etching apparatus according to an embodiment of this application;
[0020] Figure 2 This is a schematic diagram showing the relative position structure of a radio frequency generator and a first electrode according to an embodiment of this application;
[0021] Figure 3 This is a schematic diagram of the structure of a gas distribution disk according to an embodiment of this application.
[0022] List of reference numerals in the attached diagram:
[0023] 1-Vacuum chamber, 11-First electrode, 12-Second electrode, 2-Cover, 21-First chamber, 22-Second chamber, 23-RF generator, 24-Gas distribution plate, 240-Through hole, 3-Gas supply line. Detailed Implementation
[0024] Preferred embodiments of this application are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of this application and are not intended to limit the scope of protection of this application. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.
[0025] It should be noted that in the description of this application, terms such as "upper", "lower", "left", "right", "inner", and "outer" that indicate direction or positional relationship are based on the direction or positional relationship shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the relevant device or component must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this application.
[0026] It should be noted that, in the description of this application, "and / or" indicates an optional combination relationship between two or more technical features (A, B, ...). For example, "A and / or B" means that the technical solution protected by the claim covers all of the following parallel situations: containing only feature A: the technical solution only satisfies the requirement of feature A, without necessarily including or requiring feature B; containing only feature B: the technical solution only satisfies the requirement of feature B, without necessarily including or requiring feature A; containing both feature A and feature B: the technical solution simultaneously satisfies the requirements of feature A and feature B.
[0027] Furthermore, it should be noted that, in the description of this application, unless otherwise expressly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0028] This embodiment provides an etching apparatus suitable for inductively coupled plasma etching of metallic materials. To make the working principle of the apparatus clearer and easier to understand, a wafer will be used as a typical example of the object to be etched in the description.
[0029] Figure 1 This is a partial structural schematic diagram of an etching apparatus according to an embodiment of this application. Figure 1 As shown, the etching apparatus includes a vacuum chamber 1, the interior of which serves as the space for the etching reaction, and is maintained at a low pressure by a vacuum pump system. Specifically, a wafer carrier stage (not shown) is provided inside the vacuum chamber 1 for placing the wafer to be etched. A first electrode 11 and a second electrode 12 are respectively disposed at the upper and lower ends of the vacuum chamber 1. The first electrode 11 is located at the upper end of the vacuum chamber 1 and its top opening is closed; it is called the upper electrode. The second electrode 12 is located at the lower end of the vacuum chamber 1 and its bottom opening is closed; it is called the lower electrode. The first electrode 11 is made of high-temperature resistant insulating quartz material.
[0030] Furthermore, a cover 2 is provided on the outer side of the first electrode 11. The cover 2 is tightly connected to the outer wall of the vacuum chamber 1, forming a closed space that completely covers the portion of the first electrode 11 exposed outside the vacuum chamber 1. A radio frequency generator 23 is also provided in the closed space, located on the side of the upper electrode facing away from the vacuum chamber 1. The high-frequency alternating electric field generated by the radio frequency generator 23 penetrates the first electrode 11 and enters the vacuum chamber 1, ionizing the etching gas introduced into the vacuum chamber 1 to form a high-density plasma, thereby achieving directional etching of the metal on the wafer surface.
[0031] refer to Figure 2 , Figure 2The diagram shows the relative positional relationship between the radio frequency generator 23 and the first electrode 11. In this embodiment, the radio frequency generator 23 is a spiral radio frequency coil, which is disposed outside the upper electrode.
[0032] As described in the background art, in order to maintain plasma stability and consistent etching rate during the etching process, the first electrode 11 needs to be preheated. Preheating ensures that the first electrode 11 reaches a predetermined operating temperature, preventing unstable energy loss when the electromagnetic field generated by the RF coil penetrates the quartz window due to an excessively low initial temperature, which would affect the spatial distribution and ionization efficiency of the plasma.
[0033] To address the aforementioned issues, the etching apparatus of this application achieves rapid adjustment and precise, stable control of the temperature of the first electrode 11 by circulating and supplying temperature-adjustable gas into the housing 2.
[0034] There are several ways to deliver gas into the enclosure 2. For example, a gas storage tank and a temperature control component can be installed inside the enclosure 2 to directly regulate the temperature of the gas inside the enclosure 2. Alternatively, the enclosure 2 can be connected to an external gas supply pipeline 3 through an interface. A temperature control component can be installed on the gas supply pipeline 3 to regulate the temperature of the gas inside before it enters the enclosure 2 and exchanges heat with the first electrode 11.
[0035] In a preferred embodiment, the temperature of the first electrode 11 is controlled by supplying gas into the enclosure 2 via an external gas supply pipe 3.
[0036] Specifically, the top of the cover 2 is provided with an air inlet and the bottom is provided with an exhaust outlet, forming a top-to-bottom airflow path. The air inlet is connected to an external air supply pipe 3. The gas in the air supply pipe 3 is regulated by a temperature control component and then injected into the cover 2 through the air inlet. After exchanging heat with the first electrode 11, the gas is discharged from the exhaust outlet.
[0037] In a preferred embodiment, the temperature control component mainly includes a heating module, which is used to rapidly heat the gas in the gas supply pipeline 3 to meet the preheating temperature requirements of the etching process. The heating module can take various forms, such as using a finned electric heating tube or a semiconductor heating plate.
[0038] In one specific embodiment, according to the temperature requirements of the etching process for the first electrode 11, its predetermined operating temperature needs to reach the process start-up threshold (e.g., around 90°C). Therefore, during the preheating stage, the gas supply line 3 continuously injects preheated gas, heated by the heating module, into the enclosed space through the gas inlet. The temperature of this preheated gas can be preset to be slightly higher than the target value to compensate for heat loss during the flow process. After the preheated gas enters the enclosure 2, it comes into full contact with the surface of the first electrode 11 during the flow process, and the heat of the gas itself is transferred to the first electrode 11, causing the temperature of the first electrode 11 to rise to 90°C, meeting the etching temperature requirements.
[0039] As the etching process continues, the RF coil generates heat due to its high-power operation, and its surface temperature is significantly higher than the initial temperature of the preheating gas (such as the preset 90°C reference value). At this time, when the preheating gas flows over the surface of the RF coil, it exchanges heat with the coil and carries away the accumulated heat, which is then discharged through the exhaust port. This prevents the RF coil from overheating, which could lead to attenuation of RF energy output or equipment failure. It also prevents etching accuracy deviations caused by rapid heating of the upper electrode and avoids etching interruptions caused by the upper electrode temperature exceeding the safety limit.
[0040] When the etching process is completed or the first electrode 11 needs to be removed for maintenance of the vacuum chamber 1, room temperature gas can be introduced into the gas supply line 3 to quickly reduce the temperature of the first electrode 11 and the radio frequency coil through convection heat transfer.
[0041] In industrial production, nitrogen is significantly cheaper than other inert gases, and is readily available and easy to store. Furthermore, high-purity nitrogen effectively prevents electrode surface oxidation, extends electrode lifespan, and reduces equipment maintenance costs. Therefore, in a preferred embodiment, nitrogen is introduced into the enclosure 2. Of course, this application is not limited to this, and other gases may also be used.
[0042] Practice shows that when 90°C high-temperature nitrogen is introduced into the enclosed space through the gas supply line 3 to preheat the first electrode 11, the temperature of the first electrode 11 can be raised to the process start-up temperature in only about 20 minutes; while the original method of heating with a simple radio frequency coil takes as long as 40 minutes. When the etching process is completed or when maintenance is required for the vacuum chamber 1, the temperature of the first electrode 11 and the radio frequency coil needs to be reduced. Natural cooling of the first electrode 11 takes about 1.5 hours, while introducing room temperature nitrogen can achieve rapid cooling through forced convection, which can be completed in only about 15 minutes, significantly improving the cooling efficiency.
[0043] In one embodiment, reference Figure 1 A gas distribution plate 24 is provided inside the enclosure 2. The gas distribution plate 24 is installed inside the enclosed space and divides the enclosed space into a first chamber 21 and a second chamber 22. The air inlet is connected to the first chamber 21, and the exhaust port is connected to the second chamber 22. The portion of the radio frequency generator 23 and the first electrode 11 exposed outside the vacuum chamber 1 are both located in the second chamber 22.
[0044] refer to Figure 3The gas distribution plate 24 is provided with multiple through holes 240 connecting the first chamber 21 and the second chamber 22, forming a unidirectional flow path. Specifically, gas first enters the first chamber 21 through the inlet, and driven by the pressure difference, the gas passes through the through holes 240 on the gas distribution plate 24 into the second chamber 22, and finally exits from the exhaust port. The gas distribution plate 24 can act as a physical barrier, directing the gas from the first chamber 21 into the second chamber 22 through the through holes 240. This helps optimize the gas flow path, thereby improving the heat exchange effect between the first electrode 11 and the radio frequency generator 23.
[0045] Furthermore, multiple through holes 240 are distributed in a matrix or ring array on the disk body. The hole size, spacing and opening direction are optimized by fluid dynamics simulation to ensure that the temperature-controlled gas flowing in from the first chamber 21 forms a uniform airflow when passing through the through holes 240, thereby helping to make the heat exchange between the airflow and the radio frequency generator 23 and the first electrode 11 more uniform.
[0046] In one embodiment, a radially oriented flow guide (not shown) is provided on the surface of the gas distribution disk 24 facing the second chamber 22. The flow guide extends radially from the edge of each through-hole 240 toward the interior of the second chamber 22. Here, "radially oriented" means that the flow guide's cross-sectional area perpendicular to the gas direction gradually increases along a direction away from the gas distribution disk 24, forming an overall structure resembling a trumpet or diffuser cone. When gas is injected into the second chamber 22 through the through-holes 240, the radially expanding walls of the flow guide effectively guide, diffuse, and decelerate the gas, allowing it to spread more smoothly and cover a wider area as it flows over the surface of the RF generator 23 and the first electrode 11, resulting in more uniform heat exchange and improved stability of the temperature control of the first electrode 11.
[0047] In another embodiment, the through hole 240 is "radial", that is, from the first chamber 21 to the second chamber 22, the radial area of the through hole 240 gradually increases, forming a structure similar to a trumpet or a diffusion cone. This allows the gas to spread and flow more smoothly and over a wider area across the surface of the radio frequency generator 23 and the first electrode 11, resulting in more uniform heat exchange.
[0048] In one embodiment, in order to prevent gas from bypassing the first chamber 21 and the second chamber 22 and flowing directly without passing through the through hole 240, the outer edge shape of the gas distribution plate 24 is designed to strictly match and tightly fit the cross-sectional shape of the inner peripheral wall of the cover 2.
[0049] For example, when the cross-section of the cover 2 is circular, the gas distribution plate 24 is correspondingly designed as a disc, with its circumferential edge and the inner circular wall of the cover 2 achieving a circumferential seal through the use of sealing elements. This shape-matching and tightly fitting structural design allows the gas distribution plate 24 to be securely installed inside the cover 2, ensuring that the gas entering the first chamber 21 from the inlet has only one channel to flow into the second chamber 22: the multiple pre-set through holes 240 on the gas distribution plate 24. This eliminates the possibility of gas flowing around the gap between the edge of the distribution plate and the inner wall of the cover 2. This design helps maintain the necessary pressure difference between the first chamber 21 and the second chamber 22, ensures the unidirectional flow of gas, and achieves uniform gas distribution.
[0050] refer to Figure 2 When the RF generator 23 uses a spiral RF coil, uneven heat distribution is easily formed on the surface of the first electrode 11 during the preheating process. Specifically, the planar projection profile of the spiral coil is usually smaller than the size of the first electrode 11, resulting in the edge area of the first electrode 11 not being effectively covered, forming cold spots at the edges. At the same time, the spacing between the coil's annular turns causes uneven heating of the corresponding electrode surface of the first electrode 11, leading to regional temperature differences. These heat distribution defects affect the etching effect.
[0051] Therefore, in a preferred embodiment, the orthogonal projection of the gas distribution disk 24 onto the first electrode 11 completely covers the first electrode 11, ensuring that the gas flows through the surface of the first electrode 11 without any dead zones. This design allows the gas injected into the second chamber 22 through the through-hole 240 on the gas distribution disk 24 to completely cover the entire exposed surface of the first electrode 11 during its downward flow, effectively eliminating potential heat exchange dead zones, ensuring the uniformity of the overall temperature distribution of the first electrode 11, and thus improving the etching effect.
[0052] In one embodiment, similar to the above embodiment, the orthographic projection of the gas distribution disk 24 onto the radio frequency generator 23 completely covers the radio frequency generator 23 to ensure that the gas flows through the surface of the radio frequency generator 23 without any dead angles, thereby improving the heat exchange effect between the airflow and the radio frequency generator 23.
[0053] In one embodiment, the exhaust ports on the cover 2 are located near the periphery of the first electrode 11 and employ a multi-port design. This layout significantly improves heat exchange efficiency by shortening the exhaust path of hot gas: after the gas absorbs heat by flowing across the surface of the first electrode 11, it can be quickly discharged through the nearby exhaust ports, avoiding the accumulation of heat by high-temperature gas near the surface of the first electrode 11, thus ensuring the high efficiency of the convective heat transfer process.
[0054] Furthermore, multiple exhaust ports are spaced apart along the circumference of the shroud, preferably at uniform intervals, to ensure a symmetrical and balanced gas flow path within the second chamber 22. This arrangement avoids localized airflow stagnation and improves heat exchange uniformity.
[0055] In one embodiment, the etching apparatus further includes a temperature control system for precisely controlling the temperature of the first electrode 11. This control system specifically includes: a temperature sensor disposed within the enclosed space formed by the housing 2 and mounted close to the first electrode 11, for real-time monitoring of the actual temperature of the first electrode 11; a control valve connected to the gas supply line 3, for regulating the flow rate of gas flowing into the enclosed space; and a controller communicatively connected to both the temperature sensor and the control valve. Thus, the controller can precisely control the flow rate of cooling gas flowing into the enclosed space based on the real-time temperature of the first electrode 11.
[0056] Specifically, the controller is configured to receive real-time temperature readings from a temperature sensor; compare these readings with a preset target temperature value or temperature range; generate a corresponding control signal based on the comparison result; and send the control signal to the control valve to dynamically adjust the valve's opening. For example, during the cooling phase of the first electrode 11, when a significant temperature difference is detected between the first electrode 11 and a preset temperature, the controller increases the valve opening to increase gas flow and enhance heat dissipation; when the electrode temperature decreases or approaches the target value, the controller decreases the valve opening to reduce gas flow and maintain temperature stability.
[0057] The technical solutions of this application have been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of this application is obviously not limited to these specific embodiments. Without departing from the principles of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of this application.
Claims
1. An etching apparatus, characterized in that, include: A vacuum chamber (1) for accommodating a workpiece to be etched, the vacuum chamber (1) having opposing first electrodes (11) and second electrodes (12), a portion of the first electrode (11) being located within the vacuum chamber (1), and a radio frequency generator (23) being disposed on the portion of the first electrode (11) facing away from the vacuum chamber (1). A cover (2) surrounds the outside of the first electrode (11) so that another part of the first electrode (11) and the radio frequency generator (23) are located within the enclosed space formed by the cover (2); The enclosure (2) has an air inlet and an exhaust outlet. Gas is supplied to the enclosed space through the air inlet to exchange heat with the radio frequency generator (23) and the first electrode (11). The gas after heat exchange is discharged from the exhaust outlet.
2. The etching apparatus according to claim 1, characterized in that, The etching apparatus further includes: A gas distribution plate (24) is disposed in a closed space and divides the closed space into a first chamber (21) and a second chamber (22). The air inlet is connected to the first chamber (21) and the exhaust port is connected to the second chamber (22). The radio frequency generator (23) and another part of the first electrode (11) are both located in the second chamber (22). The gas distribution plate (24) is provided with a plurality of through holes (240) connecting the first chamber (21) and the second chamber (22).
3. The etching apparatus according to claim 2, characterized in that, The plurality of through holes (240) are arranged in an array on the gas distribution disk (24).
4. The etching apparatus according to claim 2, characterized in that, The orthographic projection of the gas distribution disk (24) onto the first electrode (11) covers the first electrode (11); and / or, The orthographic projection of the gas distribution disk (24) onto the radio frequency generator (23) covers the radio frequency generator (23).
5. The etching apparatus according to claim 2, characterized in that, The gas distribution plate (24) is provided with a flow guide shroud on the surface facing the second chamber (22), and the flow guide shroud extends radially from the edge of the through hole (240) toward the second chamber (22).
6. The etching apparatus according to claim 2, characterized in that, The radial cross-section of the through hole (240) increases from the first chamber (21) to the second chamber (22).
7. The etching apparatus according to claim 2, characterized in that, The gas distribution plate (24) is attached to the inner peripheral wall of the cover (2).
8. The etching apparatus according to claim 1, characterized in that, The exhaust ports are provided in multiple ways, and the multiple exhaust ports are arranged at intervals along the circumference of the cover (2).
9. The etching apparatus according to any one of claims 1 to 8, characterized in that, The etching apparatus further includes: A gas supply line (3) is provided at the air inlet, and the gas supply line (3) is connected to a heating module.
10. The etching apparatus according to claim 9, characterized in that, The etching apparatus further includes: A temperature sensor is located in the enclosed space and is positioned close to the first electrode (11); A control valve is connected to the gas supply pipeline (3); The controller is communicatively connected to both the temperature sensor and the control valve, and controls the opening degree of the control valve based on the detection value of the temperature sensor.