Wafer bearing mechanism for optimizing edge process, etching device and etching method

Abstract

The invention discloses a wafer bearing mechanism for optimizing an edge process, an etching device and an etching method.The wafer bearing mechanism comprises a carrier and an edge ring, the carrier comprises a mounting part and a bearing part, a gas operation channel is formed between the edge ring and the bearing part, and a first gas flow channel and a second gas flow channel are formed in the carrier; the gas operation channel is matched with the first gas flow channel and the second gas flow channel, helium can control the edge temperature of the wafer, argon can effectively prevent dissimilation of the back face of the wafer, and therefore the edge process is optimized, and the overall process level is improved. The etching device comprises a wafer bearing mechanism, a cavity, a radio frequency power supply, an air supply device and a molecular pump, all the parts work cooperatively, and a stable environment is provided for an etching reaction. The etching method is realized through the etching device, the etching process is more stable and controllable through optimized process control, the production efficiency is improved, the production cost is reduced, and the requirements of different chip manufacturing processes are met.

Description

Technical Field

[0001] The present application relates to the field of wafer etching technology, and in particular to a wafer carrying mechanism, an etching device and an etching method for optimizing edge processing. Background Art

[0002] Inductively coupled plasma (ICP) technology is one of the ways to achieve wafer etching. In an inductively coupled system, electromagnetic field energy is concentrated in a vacuum chamber, which can stimulate gas discharge to form plasma, so that positively charged ions bombard the wafer surface, which can remove natural oxides or fluorocarbon residues on the wafer surface, and finally etch the desired shape on the wafer surface.

[0003] In traditional etching chambers, in order to facilitate the transfer, adsorption of wafers and self-protection, the surface size of the carrier used to contact the wafer is usually designed to be slightly smaller than the wafer size, which causes the edge of the wafer to extend beyond the carrier. There is a temperature difference between the temperature of the extended edge and the center part directly above the carrier. In the etching process, the etching of PR (Photo Resist) or PI (Polyimide) is very sensitive to temperature. Low temperature will cause the etching rate to be too slow, and high temperature will cause the colloid to expand or melt, or even produce glue paste; and the etching of PR / PI will introduce CHF 3 CF 4 Using fluorine-based gases as process gases will cause the back side of the wafer beyond the edge of the carrier to be etched. Especially in long processes, severe back etching will thin the thickness of this part of the wafer and generate excess polymer adhering to the back side of the wafer. In subsequent processes, too thin wafers will increase the risk of fragmentation, and too much polymer adhesion will affect the results of subsequent processes and reduce product yield. Summary of the invention

[0004] The purpose of the present application is to overcome the deficiencies in the prior art and to provide a wafer carrying mechanism, an etching device and an etching method for optimizing edge processing.

[0005] The present application provides a wafer carrying mechanism for optimizing edge processing, characterized in that it comprises: a carrier, the carrier comprises a mounting portion and a supporting portion, the supporting portion is arranged on the mounting portion, and the supporting portion is used to support the wafer; an edge ring is arranged on the mounting portion, is arranged in a ring shape, and surrounds the supporting portion, and there is a gap between the edge ring and the supporting portion, and the gap is used as a gas operation channel; wherein the surface diameter of the supporting portion used to contact the wafer is smaller than the diameter of the wafer, and when the carrier supports the wafer, the edge of the wafer protrudes from the supporting portion and is exposed to the gas operation channel; a first airflow channel is provided in the carrier, one end of the first airflow channel is connected to a helium supply device, and the other end passes through the side of the supporting portion and is connected to the gas operation channel; the helium supply device is used to transport helium to the first airflow channel, and the helium gas flows through When the first air flow channel is in operation, the carrier can improve the temperature of the helium by heat conduction; a second air flow channel is also provided in the carrier, one end of the second air flow channel is connected to the argon supply device, and the other end passes through the top surface of the mounting portion and is connected to the gas operating channel; the argon supply device is used to transport argon to the second air flow channel, and the atomic mass of argon is greater than the atomic mass of the process gas. After the argon is blown into the gas operating channel through the second air flow channel, it can prevent the process gas from contacting the back of the wafer; during the process, the helium is blown to the edge of the wafer through the first air flow channel and the gas operating channel, and the temperature of the edge of the wafer is controlled to balance the overall temperature of the wafer; the argon is blown to the back of the wafer through the second air flow channel and the gas operating channel, thereby preventing the back of the wafer from reacting.

[0006] Furthermore, from top to bottom, the inner ring of the edge ring is composed of a transition bevel, a horizontal plane and a vertical plane, the horizontal plane connects the transition bevel and the vertical plane in series; the transition bevel extends obliquely toward the supporting portion; the horizontal plane is lower than the supporting portion for contacting the surface of the wafer; there is a gap between the vertical plane and the supporting portion, and the second air flow channel is opposite to the gap; the existence of the transition bevel can prevent argon gas from rushing straight upward, mixing with the process gas above the wafer and forming laminar convection.

[0007] Furthermore, an air chamber is provided at the bottom of the vertical plane near the second gas flow channel; during the process, at least part of the argon gas can enter the air chamber, and by reducing the flow rate, the pressure difference generated can drive the argon gas to flow upward along the gas operation channel.

[0008] Furthermore, an exhaust channel is provided on the edge ring, one end of the exhaust channel is connected to the gas operation channel, and the other end passes through the outer wall of the edge ring; when the carrier supports the wafer, the exhaust channel is close to the wafer; after the argon gas sweeps the back of the wafer upward, it can flow out from the side through the exhaust channel, thereby preventing the argon gas from continuing to flow upward and interfering with the gas environment on the front side of the wafer.

[0009] Furthermore, the carrier includes a metal base and a ceramic layer, wherein the ceramic layer covers the top of the metal base and is used to contact the wafer; a third air flow channel is also provided in the carrier, wherein one end of the third air flow channel is connected to a helium supply device and the other end passes through the ceramic layer; during the process, helium is blown to the back of the wafer through the third air flow channel, which can not only improve the wafer temperature, but also confirm whether the wafer is adsorbed and fixed by the carrier by monitoring the back helium pressure.

[0010] The present application also provides an etching device, including the above-mentioned wafer supporting mechanism for optimizing edge process, and also includes: a process chamber, the wafer supporting mechanism is arranged in the process chamber, and the process chamber can provide space for wafer etching; a radio frequency power supply, connected to the carrier, used to supply power to the carrier, and the carrier can fix the wafer by electrostatic adsorption after power is turned on; a gas supply device, connected to the air inlet of the process chamber, used to transport process gas to the process chamber; a molecular pump, connected to the air outlet of the process chamber, used to extract the gas in the process chamber; wherein the air inlet is arranged above the wafer supporting mechanism, and the air outlet is arranged below the wafer supporting mechanism.

[0011] Furthermore, a first airflow channel, a second airflow channel and a third airflow channel are provided in the carrier; the etching device also includes: a first sensor, using MFC, for monitoring the helium flow in the first airflow channel; a second sensor, using MFC, for monitoring the argon flow in the second airflow channel; a third sensor, using UPC, for monitoring the helium pressure in the third airflow channel.

[0012] The present application also provides an etching method, which is implemented by the above-mentioned etching device and includes the following steps: a carrier supports a wafer; an RF power supply applies an adsorption voltage to the carrier; a helium supply device delivers low-pressure helium to the third air flow channel, and if the flow rate fed back by the third sensor is less than 1 SCCM, it indicates that the wafer has been adsorbed; the pressure of the helium delivered by the helium supply device to the third air flow channel is increased to maintain stable heat dissipation; the helium supply device delivers helium to the first air flow channel, and the two helium channels cooperate to control the temperature of the wafer; the argon supply device delivers argon to the second air flow channel; the gas supply device delivers process gas to the process chamber through the air inlet; etching is completed; the gas supply device stops delivering process gas; the argon supply device stops delivering argon; the RF power supply stops supplying power; the helium supply device delivers low-pressure helium to the third air flow channel, and if the flow rate fed back by the third sensor increases, it indicates that the wafer has been desorbed; the helium supply device stops delivering helium.

[0013] Further, when the third sensor detects a back helium pressure of 3≤p<5Torr, the helium flow rate of the first air flow channel is adjusted to 1SCCM; when the third sensor detects a back helium pressure of 5≤p<8Torr, the helium flow rate of the first air flow channel is adjusted to 3SCCM; when the third sensor detects a back helium pressure of 8≤p<10Torr, the helium flow rate of the first air flow channel is adjusted to 5SCCM; when the third sensor detects a back helium pressure of 10≤p<12Torr, the helium flow rate of the first air flow channel is adjusted to 8SCCM; when the third sensor detects a back helium pressure of p≥12Torr, the helium flow rate of the first air flow channel is adjusted to 10SCCM.

[0014] Further, the process gas is a fluorine-based gas; when the total intake volume of the process gas A is less than 100 SCCM, if the fluorine-based ratio B is less than 30%, the argon flow rate C of the second gas flow channel is 0.4AB; when the total intake volume of the process gas A is less than 100 SCCM, if the fluorine-based ratio is 30%≤B≤70%, the argon flow rate C of the second gas flow channel is 0.5AB; when the total intake volume of the process gas A is less than 100 SCCM, if the fluorine-based ratio B is greater than 70%, the argon flow rate C of the second gas flow channel is 0.6AB; When the total intake volume of process gas is 100SCCM≤A≤200SCCM, if the fluorine-based ratio B is less than 30%, the argon flow rate C of the second gas flow channel is 0.2AB; when the total intake volume of process gas is 100SCCM≤A≤200SCCM, if the fluorine-based ratio is 30%≤B≤70%, the argon flow rate C of the second gas flow channel is 0.3AB; when the total intake volume of process gas is 100SCCM≤A≤200SCCM, if the fluorine-based ratio B>70%, the argon flow rate C of the second gas flow channel is 0.4AB; When the total intake volume of process gas A>200SCCM, if the fluorine-based proportion B<30%, the argon flow rate C of the second air flow channel is 0.1AB; when the total intake volume of process gas A>200SCCM, if the fluorine-based proportion is 30%≤B≤70%, the argon flow rate C of the second air flow channel is 0.2AB; when the total intake volume of process gas A>200SCCM, if the fluorine-based proportion B>70%, the argon flow rate C of the second air flow channel is 0.3AB.

[0015] The present application provides a wafer carrying mechanism for optimizing edge process, comprising a carrier and an edge ring, the carrier comprising a mounting portion and a supporting portion, a gas operation channel between the edge ring and the supporting portion, a first gas flow channel and a second gas flow channel in the carrier, the first gas flow channel connecting a helium supply device and a gas operation channel, and the second gas flow channel connecting an argon supply device and a gas operation channel; the gas operation channel cooperates with the first gas flow channel and the second gas flow channel, helium can control the edge temperature of the wafer, and argon can effectively prevent the back side of the wafer from being alienated, thereby optimizing the edge process and improving the overall process level; in the wafer carrying mechanism provided by the present application, the position relationship of each component is clear, the coordination method is scientific, the gas operation channel, the first gas flow channel and the second gas flow channel are reasonably designed, the effective transportation and function of helium and argon are realized, and the stability and reliability of the operation of the whole mechanism are ensured; at the same time, the present application makes full use of the thermal conductivity of helium and the atomic mass and inert gas characteristics of argon, and solves key problems such as wafer edge temperature control and back side alienation without affecting the normal process, and has high practicality and innovation.

[0016] The present application also provides an etching device, including the above-mentioned wafer carrier mechanism, and also including a process chamber, a radio frequency power supply, a gas supply device and a molecular pump. The carrier can fix the wafer by electrostatic adsorption, the gas supply device can deliver process gas to the process chamber through the air inlet, and the molecular pump can extract the gas in the chamber through the air outlet. The air inlet is arranged above the wafer carrier mechanism, and the air outlet is arranged below the wafer carrier mechanism. A gas flow path from top to bottom is formed in the process chamber, which is conducive to the timely discharge of the gas in the process chamber, thereby effectively maintaining the gas composition and pressure stability in the process chamber, so as to facilitate the continuous and stable progress of the process reaction. The various components of the etching device provided by the present application work together to provide a stable environment for the etching reaction. From precise wafer fixation to effective gas circulation, and then to optimized overall temperature control, it is helpful to maintain the stability of various parameters in the etching process, improve the repeatability and controllability of the etching process, and facilitate the large-scale production of high-quality chips.

[0017] The present application also provides an etching method, which is implemented by the above-mentioned etching device. The entire etching method precisely controls the supply of each gas, the adsorption and desorption of the wafer, and other links, and each step is closely coordinated. This optimized process control makes the etching process more stable and controllable, which helps to improve production efficiency, reduce production costs, and meet the needs of different chip manufacturing processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the structure of an etching device provided in this application; Figure 2 for Figure 1 Magnified view of the structure within the middle circle. DETAILED DESCRIPTION

[0019] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0020] The present application provides a wafer carrying mechanism for optimizing edge processing, including: a carrier 10, the carrier 10 includes a mounting portion 11 and a supporting portion 12, the supporting portion 12 is arranged on the mounting portion 11, and the supporting portion 12 is used to support the wafer; an edge ring 20, which is arranged on the mounting portion 11, is arranged in a ring shape and surrounds the supporting portion 12, and there is a gap between the edge ring 20 and the supporting portion 12, and the gap is used as a gas operation channel; wherein the surface diameter of the supporting portion 12 used to contact the wafer is smaller than the wafer diameter, and when the carrier 10 supports the wafer, the edge of the wafer protrudes from the supporting portion 12 and is exposed to the gas operation channel.

[0021] For details, please refer to Figure 1 In the illustrated embodiment, the main body of the carrier 10 is generally in a convex shape, and is formed by stacking two truncated cones, with the mounting portion 11 disposed at the bottom and the supporting portion 12 disposed at the top and located at the center of the mounting portion 11. The mounting portion 11 and the supporting portion 12 are integrally formed. The diameter of the supporting portion 12 is smaller than the diameter of the mounting portion 11.

[0022] Specifically in the actual device, the wafer carrying mechanism also includes a pin, and the carrier 10 is provided with a movable hole that runs vertically through, and the pin is inserted into the movable hole, and the carrier 10 and the pin can move relative to each other in the vertical direction. When receiving the wafer, the pin passes through the movable hole and protrudes from the carrier 10, so as to cooperate with the transfer robot to receive the wafer; then, the pin is lowered or the carrier 10 is raised, and the wafer originally on the pin can be placed flat on the carrier 10. The carrier 10 can fix the wafer by electrostatic adsorption, ensuring that the wafer maintains a precise position during the etching process, avoiding position deviation caused by factors such as vibration, and providing a basic guarantee for the accuracy and consistency of etching. The carrier 10 is often also provided with a temperature control mechanism, which can adjust the temperature of the carrier 10, and the carrier 10 can make the wafer thereon have the process temperature required for etching by heat exchange.

[0023] Continue to refer to Figure 1The edge ring 20 is roughly in the shape of a thick-walled cylinder. The edge ring 20 is fixedly mounted on the mounting portion 11 and surrounds the supporting portion 12 in its circle. There is a gap between the edge ring 20 and the supporting portion 12, and gas can flow in the gap, so the gap is used as a gas operation channel. The gas operation channel is also cylindrical. The edge ring 20 is slightly higher than the supporting portion 12. When the supporting portion 12 supports the wafer, the wafer is confined in the edge ring 20. The edge ring 20 has the function of limiting and protecting.

[0024] Optionally, the edge ring 20 is made of ceramics. Ceramics have insulating properties and can adjust the electric field and plasma distribution in the edge area of ​​the wafer during the etching process.

[0025] In a plasma environment, the etching rate and uniformity at the edge of the wafer are often different from those in the central area. The edge ring 20 can optimize the interaction between the plasma in the edge area and the wafer surface through its special material and structural characteristics, making the etching conditions in the edge area closer to those in the central area, thereby improving the etching uniformity.

[0026] Specifically, the carrier 10 is provided with a first airflow channel 10a, one end of which is connected to the helium supply device, and the other end passes through the side of the supporting portion 12 and is connected to the gas operation channel; the helium supply device is used to transport helium to the first airflow channel 10a, and when the helium flows through the first airflow channel 10a, the carrier 10 can improve the temperature of the helium through heat conduction; the carrier 10 is also provided with a second airflow channel 10b, one end of the second airflow channel 10b is connected to the argon supply device, and the other end passes through the top surface of the mounting portion 11 and is connected to the gas operation channel The argon gas supply device is used to deliver argon gas to the second gas flow channel 10b. The atomic mass of argon gas is greater than the atomic mass of the process gas. After the argon gas is blown into the gas operating channel through the second gas flow channel 10b, it can prevent the process gas from contacting the back of the wafer. During the process, helium gas is blown to the edge of the wafer through the first gas flow channel 10a and the gas operating channel, and the edge of the wafer is temperature-controlled to balance the overall temperature of the wafer. Argon gas is blown to the back of the wafer through the second gas flow channel 10b and the gas operating channel, thereby preventing the back of the wafer from reacting.

[0027] For details, please refer to Figure 1 and Figure 2 In the illustrated embodiment, a gas operation channel is formed between the edge ring 20 and the supporting portion 12. The top of the gas operation channel is open, the bottom is connected to the second gas flow channel 10b, and the right side is connected to the first gas flow channel 10a. When the carrier 10 supports the wafer, due to the larger size of the wafer, the edge of the wafer will be exposed outside the supporting portion 12 and in the gas operation channel.

[0028] Continue to refer to Figure 1 and Figure 2The carrier 10 is provided with a first airflow channel 10a and a second airflow channel 10b. The lower end of the first airflow channel 10a penetrates the bottom surface of the mounting portion 11 and is used to connect the helium supply device, and the upper end of the first airflow channel 10a penetrates the side surface of the supporting portion 12 and is connected to the gas operation channel. The lower end of the second airflow channel 10b penetrates the bottom surface of the mounting portion 11 and is used to connect the argon supply device, and the upper end of the second airflow channel 10b penetrates the top surface of the mounting portion 11 and is used to connect the helium supply device.

[0029] It is easy to understand that since the center area of ​​the wafer is in contact with the support portion 12, the carrier 10 can directly conduct heat to this area, thereby ensuring that the area maintains the process temperature. However, the edge area of ​​the wafer is outside the support portion 12, so that this area cannot directly conduct heat to the carrier 10, and therefore, the edge area of ​​the wafer is often not at the process temperature.

[0030] The first airflow channel 10a is added. During the process, helium can exchange heat with the carrier 10 when flowing through the first airflow channel 10a. Since helium has excellent thermal conductivity (helium atoms are the second lightest atoms after hydrogen atoms, with a thermal conductivity of 0.1682 W / m·°C), when flowing through the first airflow channel 10a, the carrier 10 can adjust the temperature of the helium through heat conduction, so that the helium quickly reaches the process temperature. Subsequently, the helium is blown to the edge of the wafer through the gas operation channel. Heat is quickly transferred between the helium and the edge of the wafer, thereby effectively controlling the temperature of the wafer portion that exceeds the supporting portion 12, ensuring the overall temperature balance of the wafer, and avoiding the influence of uneven temperature on the process effect.

[0031] When the wafer is subjected to surface treatment processes (such as etching, coating, etc.), process gas is also introduced into the process chamber to ionize the process gas and generate plasma to achieve the relevant process. When the process gas moves in the process chamber, it may move downward and contact the back side of the wafer, causing the back side to react and become abnormal.

[0032] A second gas flow channel 10b is added. During the process, after the argon passes through the second gas flow channel 10b and is blown into the gas operation channel, it will form a barrier layer in the gas operation channel due to its large atomic mass and kinetic energy; when the process gas particles move to the gas operation channel, the argon gas particles will collide with it and push it away, making it difficult for the process gas to contact the back of the wafer. At the same time, as an inert gas, argon has basically no effect on the process except for changing the gas ratio; therefore, the use of argon as the back protection gas will not affect the normal process, and can effectively prevent the occurrence of wafer backside alienation.

[0033] In simple terms, the high thermal conductivity of helium can effectively and reliably control the temperature of the wafer edge and achieve temperature balance of the entire wafer, thereby improving the stability of wafer temperature and the controllability of environmental parameters during the process, which helps to improve the accuracy and quality of processes such as etching. The use of argon can prevent the process gas from contacting the back of the wafer, thereby avoiding the occurrence of wafer backside alienation, ensuring the integrity of the wafer structure and improving the yield rate of chip manufacturing.

[0034] In summary, by reserving a gas operating channel through the carrier 10 and the edge ring 20, in conjunction with the first air flow channel 10a and the second air flow channel 10b, helium can control the edge temperature of the wafer, and argon can effectively prevent the back side of the wafer from being alienated, thereby optimizing the edge process and improving the overall process level; in the wafer carrying mechanism provided by the present application, the positional relationship of each component is clear, the coordination method is scientific, and the gas operating channel, the first air flow channel 10a and the second air flow channel 10b are reasonably designed, which realizes the effective transportation and function of helium and argon, and ensures the stability and reliability of the operation of the entire mechanism; at the same time, the present application makes full use of the thermal conductivity of helium and the atomic mass and inert gas characteristics of argon, and solves key problems such as wafer edge temperature control and back side alienation without affecting the normal process, and has high practicality and innovation.

[0035] Figure 1 In the illustrated embodiment, the main body of the carrier 10 is roughly convex in shape, and is composed of two stacked cones of a mounting portion 11 and a supporting portion 12; the edge ring 20 is roughly thick-walled cylindrical, and the edge ring 20 is fixedly arranged on the mounting portion 11 and surrounds the supporting portion 12 within its circle; a gas operating channel is formed between the edge ring 20 and the supporting portion 12, and the gas operating channel is a vertically extending annular structure.

[0036] In order to facilitate helium and argon to fully enter the annular gas operation channel, in one embodiment, a plurality of first gas flow channels 10a and a plurality of second gas flow channels 10b are provided in the carrier 10. Taking the first gas flow channel 10a as an example, the plurality of first gas flow channels 10a are arranged at intervals along the circumferential direction, and the lower end of each first gas flow channel 10a is connected to the helium supply device and the upper end is connected to the gas operation channel. The gas outlets of these first gas flow channels 10a point to different directions, so that helium can flow into the gas operation channel from different directions, thereby ensuring that the edge area of ​​the wafer can be fully blown by helium.

[0037] In another embodiment, an annular flow channel is respectively provided inside the supporting portion 12 near the outer peripheral wall and inside the mounting portion 11 near the top wall, and the annular flow channel is part of the first airflow channel 10a and the second airflow channel 10b. There are a plurality of small holes evenly distributed along the circumference of the annular flow channel, and any small hole penetrates the wall and connects the gas operation channel. These small holes are the outlet holes of the first airflow channel 10a and the second airflow channel 10b. After helium and argon enter the annular flow channel from a single air inlet, they can be evenly distributed in the annular flow channel, and then enter the gas operation channel through the small holes. In this embodiment, helium and argon have been initially homogenized in the annular flow channel before entering the gas operation channel, so that helium and argon can enter the gas operation channel more comprehensively and evenly; the design of a single air inlet can also reduce the sealing and other problems that may be caused by multiple air inlets.

[0038] In another embodiment, the first airflow channel 10a and the second airflow channel 10b are arranged in a spiral structure. Taking the first airflow channel 10a as an example, starting from the air inlet, the first airflow channel 10a extends vertically and upward in a spiral to the side of the supporting portion 12. During the process, when the helium flows in the spiral channel, it will produce certain disturbances and mixing due to the special shape of the channel, which helps to distribute the gas more evenly; after the helium fed along the spiral path enters the gas operation channel, it can cover the gas operation channel more comprehensively under the action of inertia. This embodiment uses a spiral structure to increase the flow path and mixing effect of the gas, while also reducing the space occupied by the channel to a certain extent, thereby achieving more efficient gas delivery within the limited structure of the carrier 10.

[0039] Optionally, from bottom to top, the outlet end of the first gas flow channel 10a connected to the gas operation channel extends obliquely toward the gas operation channel to facilitate the helium gas to be blown toward the edge of the wafer.

[0040] For details, please refer to Figure 2 In the illustrated embodiment, the first air flow channel 10a includes a vertical air inlet section and an inclined air outlet section; the lower end of the vertical air inlet section penetrates the bottom surface of the mounting portion 11 and is used to connect to the helium supply device, and the upper end of the inclined air outlet section penetrates the side surface of the supporting portion 12 and connects to the gas operation channel. From right to left, the inclined air outlet section extends upward. After the helium enters the inclined air outlet section through the vertical air inlet section, it can flow upward and outward under the guidance of the inclined air outlet section.

[0041] When helium is ejected from the inclined outlet section, since the direction of the gas flow forms a certain angle with the wall of the gas operation channel and the edge of the wafer, a velocity component will be generated along the inclined outlet section and pointing to the edge of the wafer. This allows the helium to rush to the edge of the wafer more directly and efficiently after leaving the inclined outlet section. At the same time, the inclined outlet section can also change the flow field distribution of the helium after it is ejected, so that the helium forms a specific flow pattern in the gas operation channel, which helps it to more fully contact the edge of the wafer in a limited space, thereby achieving rapid heat transfer and effective temperature regulation.

[0042] The inclined outlet section allows helium to be blown more accurately to the edge of the wafer, reducing the diffusion and loss of helium during the transmission process, so that the heat carried by the helium can be transferred to the edge of the wafer more quickly. Compared with vertical or horizontal outlet directions, this design can achieve temperature adjustment of the edge of the wafer in a shorter time, which is conducive to improving temperature control efficiency and meeting the process requirements for rapid temperature response.

[0043] In addition, helium blowing toward the edge of the wafer at a specific angle will form a more uniform airflow distribution at the edge of the wafer. Uniform airflow helps to achieve more uniform heat exchange at the edge of the wafer, avoiding temperature differences caused by uneven local airflow, thereby making the overall temperature of the wafer more balanced, improving the uniformity of temperature control, and helping to improve the accuracy and consistency of processes such as etching, and reducing process deviations caused by uneven temperatures.

[0044] Optionally, from bottom to top, the second gas flow channel 10b vertically extends toward the gas operation channel, so that the argon gas blocks the process gas from entering the gas operation channel from top to bottom.

[0045] During the process, the process gas in the chamber is affected by factors such as gravity and gas flow, and tends to enter the gas operation channel from top to bottom and contact the back of the wafer. The second gas flow channel 10b is set to extend vertically toward the gas operation channel, and the argon gas can be ejected vertically upward. Based on the principle of gas dynamics, argon gas has a large atomic mass, and it forms a vertical upward gas flow column after being ejected. When the process gas moves downward, it will meet the vertical upward argon gas flow column. This vertical gas flow distribution can resist the process gas moving from top to bottom to the greatest extent, greatly improves the blocking efficiency of the process gas, and can effectively prevent the process gas from entering the gas operation channel and contacting the back of the wafer.

[0046] Optionally, from top to bottom, the inner ring of the edge ring 20 is composed of a transition bevel 21, a horizontal plane and a vertical plane 22, the horizontal plane connects the transition bevel 21 and the vertical plane 22 in series; the transition bevel 21 extends obliquely toward the supporting portion 12; the horizontal plane is lower than the supporting portion 12 for contacting the surface of the wafer; the vertical plane 22 is spaced from the supporting portion 12, and the second air flow channel 10b is opposite to the space; the presence of the transition bevel 21 can prevent argon gas from rushing straight upward, mixing with the process gas above the wafer and forming laminar convection.

[0047] For details, please refer to Figure 2 In the illustrated embodiment, the edge ring 20 faces the right side of the supporting portion 12, i.e., the inner ring thereof. From top to bottom, the inner ring of the edge ring 20 is formed by a transition slope 21, a horizontal plane, and a vertical plane 22 connected in sequence. Since the edge ring 20 is an annular structure, the upper end of the edge ring 20 where the transition slope 21 is located is roughly in the shape of a tapered trumpet. At this time, the gas operation channel is roughly divided into three sections, namely, a vertical extension section formed by the vertical plane 22 and the supporting portion 12, a horizontal extension section formed by the horizontal plane and the wafer, and an inclined extension section formed by the transition slope 21 and the wafer.

[0048] When the process gas flows downward and the argon gas flows upward, the two directly collide vertically, which easily leads to gas mixing and the formation of laminar convection. Laminar convection will change the original concentration, distribution and reaction activity of the process gas, thereby interfering with the normal progress of the process.

[0049] The design of the transition slope 21 can change the flow direction of the argon gas. According to the principle of fluid mechanics, gas tends to flow along the solid surface. Therefore, when the argon gas encounters the transition slope 21 during its upward flow, the argon gas will change its flow path along the inclination direction of the transition slope 21. In this way, the argon gas no longer rushes vertically upward, which reduces the possibility of directly mixing with the process gas and forming laminar convection.

[0050] By preventing the generation of laminar convection, the stability of the process gas can be ensured, providing a stable environment for the process reaction, which helps to improve the surface treatment effect.

[0051] At the same time, the combination of the horizontal plane and the vertical plane 22 further guides and constrains the flow of the argon gas, so that it forms a stable and effective blocking gas flow in the gas operation channel, and finally reliably prevents the process gas from sinking.

[0052] Optionally, a gas chamber 23 is provided at the bottom of the vertical plane 22 near the second gas flow channel 10b; during the process, at least part of the argon gas can enter the gas chamber 23, and by reducing the flow rate, the pressure difference generated can drive the argon gas to flow upward along the gas operation channel.

[0053] For details, please refer to Figure 2In the illustrated embodiment, an air chamber 23 recessed to the left is provided on the right side of the edge ring 20 and close to the bottom of the mounting portion 11. The cross section of the air chamber 23 is trapezoidal and has a certain volume.

[0054] During the process, argon enters the gas operation channel from bottom to top, and part of the argon directly enters the gas chamber 23. According to the principles of fluid mechanics, when the gas enters the relatively wide gas chamber 23 from the relatively narrow second gas flow channel 10b), the gas flow rate will decrease rapidly due to the sudden increase in the flow area. According to Bernoulli's principle, during the flow of fluid, the flow rate is inversely proportional to the pressure. Therefore, when the flow rate of argon in the gas chamber 23 decreases, the pressure in the gas chamber 23 will increase relatively, while the pressure in the gas operation channel above the gas chamber 23 will decrease relatively, thereby forming a pressure difference between the gas chamber 23 and the gas operation channel. This pressure difference can serve as a driving force to prompt the argon in the gas chamber 23 to flow upward along the gas operation channel, further enhancing the blocking airflow formed by the argon in the gas operation channel, thereby effectively preventing the process gas from contacting the back of the wafer downward.

[0055] Optionally, an exhaust channel 20a is provided on the edge ring 20, one end of the exhaust channel 20a is connected to the gas operation channel, and the other end passes through the outer wall of the edge ring 20; when the carrier 10 supports the wafer, the exhaust channel 20a is close to the wafer; after the argon gas sweeps the back side of the wafer upward, it can flow out from the side through the exhaust channel 20a, thereby preventing the helium gas from continuing to flow upward and interfering with the gas environment on the front side of the wafer.

[0056] For details, please refer to Figure 2 In the illustrated embodiment, from top to bottom, the inner ring of the edge ring 20 is formed by sequentially connecting a transition slope 21, a horizontal plane, and a vertical plane 22. An exhaust channel 20a is provided at the upper portion of the edge ring 20. The exhaust channel 20a extends horizontally, and the right end of the exhaust channel 20a passes through the transition slope 21, and the left end passes through the outer ring wall of the edge ring 20. When the carrier 10 supports the wafer, the right end of the exhaust channel 20a faces the wafer.

[0057] It is easy to understand that when the exhaust channel 20a is not set, the argon gas will continue to diffuse upward after being purged upward, which may interfere with the gas environment on the front side of the wafer and affect the process on the front side. According to the basic principle of gas flow, the gas always tends to flow from the high-pressure area to the low-pressure area, and the other end of the exhaust channel 20a penetrates the outer wall of the edge ring 20 and is closer to the gas outlet of the process chamber than the gas inlet of the process chamber, which makes the pressure in the exhaust channel 20a lower than the pressure in the gas operation channel and above the wafer where the process gas is located. Under the effect of the natural flow of the gas and the slight pressure difference inside and outside the channel diffusion, the argon gas will preferentially choose to flow out through the exhaust channel 20a.

[0058] Similarly, the helium gas will also preferentially flow out through the exhaust channel 20 a instead of flowing upward to disturb the gas environment on the front side of the wafer.

[0059] Optionally, a plurality of exhaust channels 20 a are provided on the edge ring 20 , and the plurality of exhaust channels 20 a are spaced apart along the circumferential direction so as to facilitate the helium and argon in the gas operation channel to flow out quickly and evenly.

[0060] Optionally, the cross-sectional area of ​​the exhaust channel 20a along the gas flow direction gradually increases. Specifically, at the entrance where the exhaust channel 20a is connected to the gas operation channel, the channel cross-sectional area is small, and as the channel extends toward the outer wall of the edge ring 20, the cross-sectional area gradually increases. According to the principle of fluid mechanics, when the gas flows from a smaller cross-section to a larger cross-section, the flow rate will decrease and the pressure will decrease. This variable cross-sectional design makes it easier for the argon and helium in the gas operation channel to enter the entrance of the exhaust channel 20a; when the gas flows in the exhaust channel 20a, due to the gradual decrease in pressure, a suction effect will be formed, which accelerates the speed at which the gas enters the exhaust channel 20a from the gas operation channel. At the same time, a larger outlet cross-section helps the gas to be discharged quickly. As a result, the exhaust performance can be optimized without increasing the number of exhaust channels 20a or complicating the structure of the exhaust channel 20a, ensuring that the gas in the gas operation channel is discharged in time and maintaining a good process environment. Moreover, this design has good adaptability to gases with different flow rates and flow rates, and can improve the stability of the equipment under different process conditions.

[0061] Optionally, the farther away from the gas operation channel, the lower the height of the exhaust channel 20a is, thereby promoting the outflowing helium and argon gases to move downward and away from the front side of the wafer.

[0062] Specifically, when helium and argon flow from the gas operation channel into the exhaust channel 20a, the gravity component of the gas in the vertical direction gradually increases when it flows in the exhaust channel 20a due to the gradual decrease in the height of the exhaust channel. According to the effect of gravity, the gas will naturally tend to move downward. At the same time, as the height of the exhaust channel 20a decreases, the gas circulation space becomes smaller, and the gas flow rate will increase accordingly. According to the continuity principle of the fluid, the increase in flow rate will cause the pressure of the gas in the exhaust channel 20a to decrease. Outside the exhaust channel 20a, the ambient pressure is relatively high. This pressure difference will further promote the gas to flow toward the channel outlet, and under the guidance of the trend of the height reduction of the exhaust channel 20a, the gas is more inclined to move downward. At this time, the outflowing helium and argon will move downward along the trend of the exhaust channel 20a, which can effectively prevent the gas from approaching the front of the wafer due to disordered flow during the discharge process, greatly enhancing the ability to control the gas flow direction, ensuring that the process gas environment on the front of the wafer is not disturbed, and providing a stable and reliable gas environment for the surface treatment process. In addition, reasonably guiding the gas to move downward is conducive to the orderly management of the gas inside the equipment. It makes the gas distribution in different areas of the equipment more reasonable, avoids the accumulation of gas in local areas, and helps to maintain the overall gas environment stability inside the equipment.

[0063] Optionally, when the supporting portion 12 supports the wafer, the exhaust channel 20a is facing the wafer. In this way, the argon gas purged from the back of the wafer and the helium gas overflowing from the edge of the wafer can directly enter the exhaust channel 20a via the shortest path. Compared with the non-facing design, the gas does not need to make complex turns or long-distance detours in the channel, which greatly reduces the residence time of the gas in the gas operation channel and significantly speeds up the exhaust speed. Since the gas can be discharged quickly, the accumulation of gas in the vicinity of the wafer can also be effectively avoided. In processes such as etching, gas accumulation may change the local gas concentration and pressure, thereby affecting the stability and uniformity of the plasma. The design of the exhaust channel 20a facing the wafer ensures that the gas can be discharged in time, prevents the occurrence of such adverse situations, and ensures the accuracy and consistency of the process.

[0064] The exhaust channel 20a facing the wafer can more effectively capture argon and helium that may diffuse upward, minimizing the interference of these gases on the gas environment on the front side of the wafer. The process gas on the front side of the wafer needs to maintain a specific composition, concentration and flow field distribution to achieve precise etching or other process operations. The precise positioning of the exhaust channel 20a ensures that any gas that may affect the front process can be quickly discharged, ensuring the accuracy of the front process and helping to improve the yield rate of chip manufacturing.

[0065] Optionally, the carrier 10 includes a metal base and a ceramic layer, the ceramic layer covers the top of the metal base, and the ceramic layer is used to contact the wafer; a third air flow channel is also provided in the carrier 10, one end of the third air flow channel is connected to the helium supply equipment, and the other end passes through the ceramic layer; during the process, helium is blown to the back of the wafer through the third air flow channel, which can not only improve the wafer temperature, but also confirm whether the wafer is adsorbed and fixed by the carrier 10 by monitoring the back helium pressure.

[0066] Specifically, the carrier 10 is provided with a first airflow channel 10a, a second airflow channel 10b and a third airflow channel. The first airflow channel 10a and the second airflow channel 10b penetrate the metal base, and one end of the third airflow channel penetrates the metal base and the other end extends to penetrate the ceramic layer.

[0067] In the surface treatment process, temperature is an important environmental condition. It can be seen from the above that the carrier 10 can directly adjust the temperature of the wafer through heat conduction. By adding a third airflow channel, helium can be blown to the back of the wafer through the third airflow channel during the process. Multiple groups of third airflow channels can be set in the carrier 10, such as multiple circles of third airflow channels along the diameter direction, so that helium can fully purge the wafer. Alternatively, a plurality of radially extending and radially distributed air guide grooves can be provided on the ceramic surface, and helium can fully purge the back of the wafer along the air guide grooves. Since helium has excellent thermal conductivity, helium flows through the third airflow channel and obtains the process temperature under the influence of the carrier 10. When the back of the wafer is purged, the helium will conduct heat with the wafer, thereby stabilizing the temperature of the wafer.

[0068] Since the ceramic layer covers the top of the metal base, the ceramic has a certain thermal insulation performance, which can reduce the heat loss to other parts of the carrier 10, so that the heat transferred by the helium can act more concentratedly on the wafer, thereby effectively regulating the temperature of the wafer and ensuring that the wafer maintains the process temperature during the process, thereby meeting the strict temperature requirements of different processes.

[0069] In processes such as etching and photolithography, slight fluctuations in temperature may affect the accuracy and effect of the process. By setting up a third airflow channel, a helium auxiliary carrier 10 can be introduced to control the temperature of the wafer, so as to better achieve precise adjustment of the wafer temperature. Accurate temperature control helps to ensure the consistency of the etching rate, the accuracy of the photolithography pattern, etc., which is conducive to improving the yield rate of chip manufacturing and improving the overall process quality. At the same time, the thermal insulation effect of the ceramic layer further enhances the accuracy of temperature control, avoids unnecessary heat loss, and enables heat to act more effectively on the wafer.

[0070] When helium is purged on the back of the wafer, a pressure area, namely the back helium pressure, is formed between the wafer and the ceramic layer. If the wafer is firmly adsorbed and fixed by the carrier 10, the back helium pressure will be in a relatively stable numerical range. This is because good adsorption means that the gap between the wafer and the ceramic layer is relatively stable, and the flow and pressure distribution of helium in this gap are also relatively stable. However, if the wafer is not adsorbed correctly, for example, there is local warping or incomplete bonding, then the gap between the wafer and the ceramic layer will change, and the flow resistance of helium will also change, which will cause the back helium pressure to fluctuate or deviate from the normal range. By monitoring the changes in the back helium pressure in real time, it can be determined whether the wafer is adsorbed and fixed by the carrier 10.

[0071] The back helium pressure is used to confirm whether the wafer is adsorbed and fixed, providing a real-time monitoring method for the process. In the chip manufacturing process, the adsorption state of the wafer is directly related to the stability and reliability of the process. If the wafer shifts during the process or is not adsorbed firmly, it may cause serious problems such as uneven etching and pattern deviation. By real-time monitoring of the back helium pressure, once the pressure is abnormal, the operator can take immediate measures, such as readjusting the adsorption parameters or checking the equipment status, to avoid process failures caused by wafer adsorption problems, thus ensuring the stability and continuity of the entire process.

[0072] The carrier 10 realizes temperature control and back helium pressure monitoring at the same time by adding a third airflow channel. This multifunctional design effectively simplifies the overall structure of the device. Compared with the traditional temperature control system and adsorption monitoring system, the number and complexity of components inside the device are reduced, and the manufacturing cost and maintenance difficulty of the device are reduced. At the same time, the simplified structure also helps to improve the operating stability of the device and reduce the possible failure points due to too many components.

[0073] The present application also provides an etching device, including the above-mentioned wafer supporting mechanism for optimizing edge process, and also includes: a process chamber, the wafer supporting mechanism is arranged in the process chamber, and the process chamber can provide space for wafer etching; a radio frequency power supply, connected to the carrier 10, used to supply power to the carrier 10, and the carrier 10 can fix the wafer by electrostatic adsorption after being powered on; a gas supply device, connected to the air inlet of the process chamber, used to transport process gas to the process chamber; a molecular pump, connected to the air outlet of the process chamber, used to extract the gas in the process chamber; wherein the air inlet is arranged above the wafer supporting mechanism, and the air outlet is arranged below the wafer supporting mechanism.

[0074] For details, please refer to Figure 1In the illustrated embodiment, the process chamber is a relatively sealed chamber, and the carrier 10 is arranged at the bottom of the process chamber. The RF power supply is arranged outside the process chamber and connected to the carrier 10 through a cable. An air inlet is provided at the top of the process chamber, and the air inlet is connected to the air supply device through a pipeline; an air outlet is provided at the bottom of the process chamber, and the air outlet is located on one side of the carrier 10, and the air outlet is connected to the molecular pump through a pipeline.

[0075] The gas supply device delivers process gas to the process chamber through the air inlet. Optionally, a coil is also provided in the process chamber, which can ionize the process gas to generate plasma, and the plasma can chemically react or physically sputter with the material on the surface of the wafer, thereby realizing the etching process of the wafer. In this process, the edge ring 20, the air flow channel and other structures of the wafer support mechanism work together to optimize the edge process and ensure the uniformity and accuracy of the etching. The air inlet is arranged above the carrier 10, so that the process gas can evenly cover the processing space from top to bottom, providing the necessary reactants for etching. At the same time, the molecular pump extracts the gas in the cavity through the outlet below. In this way, a gas flow path from top to bottom is formed, which is conducive to the timely discharge of the gas in the process chamber, thereby effectively maintaining the gas composition in the process chamber and keeping the pressure stable, so as to facilitate the continuous and stable progress of the process reaction.

[0076] In a specific embodiment, the RF power supply applies a voltage of ±1500V to the carrier 10. When the RF power supply supplies power to the carrier 10, according to the principle of electrostatic adsorption, the Coulomb type ESC can polarize the charge on the back of the wafer by partitioning the positive and negative poles, so that an electrostatic field is generated on the surface of the carrier 10, thereby firmly adsorbing the wafer, ensuring that the wafer maintains a stable position during the etching process, and avoiding etching deviation due to displacement.

[0077] Specifically, the wafer to be etched is placed on the carrier 10 of the wafer carrying mechanism, and the RF power supply is turned on so that the carrier 10 fixes the wafer by electrostatic adsorption. The gas supply device delivers process gas to the process chamber through the air inlet. The coil is energized to ionize the process gas and generate plasma. The active particles in the plasma react with the surface material of the wafer to start the etching process. During this period, helium controls the temperature of the entire wafer through the first air flow channel 10a and the third air flow channel respectively, and argon is blown to the back of the wafer through the second air flow channel 10b to prevent the process gas from contacting the back of the wafer and causing the back to be alienated. At the same time, the structural design of the edge ring 20 can prevent argon and helium from excessively mixing with the process gas above the wafer, ensuring that the etching reaction is mainly carried out on the front of the wafer. The waste gas and unreacted gas generated during the etching process are extracted through the outlet under the action of the molecular pump. When the preset etching time or etching depth is reached, the RF power supply is stopped, the various gas supply devices are turned off, and the molecular pump is continued to run for a period of time to discharge the residual gas in the process chamber as much as possible to complete the etching.

[0078] The various components of the etching device provided in this application work together to provide a stable environment for the etching reaction. From precise wafer fixation to effective gas circulation and optimized overall temperature control, all of these help maintain the stability of various parameters during the etching process, improve the repeatability and controllability of the etching process, and facilitate the large-scale production of high-quality chips.

[0079] Optionally, a first airflow channel 10a, a second airflow channel 10b and a third airflow channel are provided in the carrier 10; the etching device also includes: a first sensor, using MFC, for monitoring the helium flow in the first airflow channel 10a; a second sensor, using MFC, for monitoring the argon flow in the second airflow channel 10b; a third sensor, using UPC, for monitoring the helium pressure in the third airflow channel.

[0080] Among them, the first sensor and the second sensor use MFC (mass flow controller), which is based on the principle of thermal mass flow measurement. Inside the MFC, there is a heating element to heat the gas, and there are two temperature sensors to measure the gas temperature upstream and downstream of the heating element respectively. When the gas flows through, it will take away heat, causing the upstream and downstream temperature difference to change. According to the relationship between the heat taken away by the gas and the mass flow rate of the gas, by measuring this temperature difference and combining the physical properties of the gas (such as specific heat capacity, etc.), the mass flow rate of the gas can be accurately calculated. For the helium in the first airflow channel 10a and the argon in the second airflow channel 10b, the MFC can accurately monitor their flow in real time to accurately control the gas supply.

[0081] The UPC (Universal Pressure Controller) used by the third sensor measures pressure by detecting the deformation of the pressure sensitive element. In the third airflow channel, when the helium generates pressure, it will cause a slight deformation of the pressure sensitive element. The UPC can convert this deformation into an electrical signal, and after signal processing and calibration, it can accurately display the pressure value of the helium. By monitoring the back helium pressure, on the one hand, it can reflect the fit between the wafer and the carrier 10, and on the other hand, it can also assist in judging the stability of the gas environment during the process.

[0082] During the etching process, helium is delivered to the first airflow channel 10a, argon is delivered to the second airflow channel 10b, and helium is delivered to the third airflow channel. The first sensor (MFC) monitors the flow rate of helium in the first airflow channel 10a in real time and feeds back the flow rate data to the control system; the second sensor (MFC) monitors the flow rate of argon in the second airflow channel 10b in real time and feeds back the flow rate data to the control system; the third sensor (UPC) monitors the pressure of helium in the third airflow channel in real time and feeds back the pressure data to the control system. The control system continuously receives data fed back by the three sensors. If the helium flow rate in the first airflow channel 10a deviates from the preset value, the control system will adjust the output of the helium supply device to restore the helium flow rate to the preset value to ensure the stability of the temperature control of the wafer edge. Similarly, if the argon flow rate in the second airflow channel 10b is abnormal, the control system will adjust the argon supply in time to ensure the protection effect on the back of the wafer. For the helium pressure in the third airflow channel, if the pressure value fluctuates greatly, it may mean that the adsorption state of the wafer and the carrier 10 has changed. The control system will issue an alarm to prompt the operator to check and handle it to avoid affecting the etching quality due to wafer adsorption problems. After etching is completed, the gas supply equipment is turned off, and each sensor continues to monitor the residual gas in the airflow channel until the gas is exhausted. At the same time, the sensor stores and records the data of the entire process for subsequent analysis and optimization of the etching process.

[0083] The present application also provides an etching method, which is implemented by the above-mentioned etching device, and includes the following steps: a carrier 10 supports a wafer; an RF power supply applies an adsorption voltage to the carrier 10; a helium supply device delivers low-pressure helium to the third air flow channel, and if the flow rate fed back by the third sensor is less than 1 SCCM, it indicates that the wafer has been adsorbed; the helium pressure delivered by the helium supply device to the third air flow channel is increased to maintain stable heat dissipation; the helium supply device delivers helium to the first air flow channel 10a, and the two helium gas cooperates to control the temperature of the wafer; the argon supply device delivers argon to the second air flow channel 10b; the gas supply device delivers process gas to the process chamber through the air inlet; etching is completed; the gas supply device stops delivering process gas; the argon supply device stops delivering argon; the RF power supply stops supplying power; the helium supply device delivers low-pressure helium to the third air flow channel, and if the flow rate fed back by the third sensor increases, it indicates that the wafer has been desorbed; the helium supply device stops delivering helium.

[0084] It is easy to understand that the RF power supply applies an adsorption voltage to the carrier 10 so that the carrier 10 can fix the wafer. When the wafer is adsorbed, a relatively sealed space is formed between the wafer and the ceramic layer of the carrier 10, and the resistance of helium entering the space through the third airflow channel increases, and the flow rate decreases accordingly. If the flow rate fed back by the third sensor is less than 1 SCCM (standard cubic centimeters per minute), it indicates that the wafer has been successfully adsorbed. After the RF power supply stops supplying power, low-pressure helium is delivered to the first airflow channel 10a again. At this time, if the wafer has been desorbed, the sealed space between the wafer and the carrier 10 is destroyed, the resistance of helium passing through the third airflow channel decreases, and the flow rate increases. By monitoring the increase in the flow rate fed back by the third sensor, it can be determined that the wafer has been desorbed. The adsorption and desorption state of the wafer can be determined by monitoring the helium flow rate in the third airflow channel. This method is simple and accurate. It can ensure that the wafer is firmly adsorbed before etching to avoid etching deviation due to loose adsorption; and it can accurately determine desorption after etching, which is convenient for subsequent wafer unloading operations, and improves the reliability and stability of the etching process.

[0085] Since helium has excellent thermal conductivity, blowing helium to the wafer through the first airflow channel 10a and the third airflow channel can achieve comprehensive temperature control of the wafer. The helium blown out of the first airflow channel 10a mainly dissipates heat at the edge of the wafer, and the helium blown out of the third airflow channel dissipates heat at the center area of ​​the wafer. The cooperation of the two helium channels can ensure that the overall temperature of the wafer is balanced during the etching process. The stable temperature helps to maintain the consistency of the etching rate, improve the accuracy and uniformity of the etching pattern, and thus improve the yield rate of chip manufacturing.

[0086] Since the atomic mass of argon is greater than that of process gas, blowing argon through the second gas flow channel 10b can form a barrier on the back of the wafer, preventing the process gas from contacting the back of the wafer, preventing back etching, and ensuring the integrity of the wafer and the accuracy of the etching process.

[0087] In a specific embodiment, the etching method includes a preparation stage, an etching stage and an etching end stage.

[0088] Preparation stage: Place the wafer to be etched on the carrier 10 and close the process chamber; Turn on the RF power supply and apply a ±1500V adsorption voltage to the carrier 10, so that the carrier 10 generates an electrostatic field to adsorb the wafer; Start the helium supply device to deliver 4Torr helium to the third gas flow channel. If the UPC feedback flow rate is less than 1SCCM, it indicates that the wafer has been firmly adsorbed. The pressure of helium delivered by the helium supply device to the third gas flow channel is increased to 8 Torr.

[0089] Etching stage: Start the helium supply device (two sets of helium supply devices may be prepared to deliver helium to the first airflow channel 10a and the third airflow channel respectively, or only one set of helium supply devices may be provided and a valve may be configured to deliver helium to the first airflow channel 10a and / or the third airflow channel in a targeted manner), deliver helium with a flow rate of 5 SCCM to the first airflow channel 10a, so that the two helium channels cooperate to control the temperature of the wafer; Start the argon gas supply device to deliver argon gas to the second gas flow channel 10b to form a barrier on the back side of the wafer to block the process gas; Start the gas supply equipment to deliver process gas to the process chamber through the gas inlet. The process gas diffuses and reacts in the process chamber to etch the wafer. During the etching stage, the gas flow rate, pressure and other parameters of each gas flow channel are continuously monitored to ensure that the UPC feedback flow rate is always less than 2 SCCM and confirm that the etching environment is stable.

[0090] End of etching stage: After the preset etching time or etching depth is reached, the gas supply equipment first stops delivering the process gas to end the etching reaction; The argon supply device then stops delivering argon, ending the protection of the back side of the wafer; The radio frequency power source stops supplying power, and the carrier 10 loses its adsorption capability; The helium supply device reduces the helium pressure delivered to the third gas flow channel to 4 Torr. At this time, the wafer is slightly blown away from the carrier 10, and the UPC feedback flow rate increases significantly (greater than 12 SCCM), indicating that the wafer has been desorbed; The helium supply device stops delivering helium and the etching process ends.

[0091] In summary, the entire etching method precisely controls the supply of each gas, the adsorption and desorption of the wafer, and each step is closely coordinated. This optimized process control makes the etching process more stable and controllable, which helps to improve production efficiency, reduce production costs, and meet the needs of different chip manufacturing processes.

[0092] It is easy to understand that, for the helium in the first air flow channel 10a, if the flow rate is too large, the wafer may be blown away, and if the flow rate is too small, the temperature control accuracy of the wafer edge may be lost, which ultimately affects the process results.

[0093] Based on a large number of tests and verifications, the UI (user interface) automatically regulates the helium flow in the first gas flow channel 10a according to the ESC back helium pressure set by the Recipe (process recipe). The comparison table is as follows:

[0094] Specifically, when the third sensor detects that the back helium pressure is 3≤p<5 Torr, the helium flow rate of the first air flow channel 10a is adjusted to 1 SCCM.

[0095] When the third sensor detects that the back helium pressure is 5≤p<8 Torr, the helium flow rate of the first air flow channel 10a is adjusted to 3 SCCM.

[0096] When the third sensor detects that the back helium pressure is 8≤p<10 Torr, the helium flow rate of the first air flow channel 10a is adjusted to 5 SCCM.

[0097] When the third sensor detects that the back helium pressure is 10≤p<12 Torr, the helium flow rate of the first air flow channel 10a is adjusted to 8 SCCM.

[0098] When the third sensor detects that the back helium pressure p≥12 Torr, the helium flow rate of the first air flow channel 10a is adjusted to 10 SCCM.

[0099] By accurately matching the back helium pressure with the helium flow rate in the first airflow channel 10a, it is possible to avoid excessive airflow impact force caused by excessive helium flow, thereby preventing the wafer from being blown away. In this way, the wafer can be stably maintained on the carrier 10, providing a stable basic condition for the etching process, reducing etching deviation caused by wafer displacement, and improving the precision of the etching pattern and the accuracy of the line.

[0100] At the same time, the helium flow rate is adjusted in real time according to the back helium pressure to ensure that appropriate heat transfer can be provided to the edge of the wafer under different process conditions. This helps to maintain the temperature balance of the entire wafer, avoid affecting the etching rate and uniformity due to abnormal edge temperature, further improve the quality and consistency of the etching process, and improve the yield rate of chip manufacturing.

[0101] This automatic control scheme is based on a large number of tests and verifications and can adapt to a variety of different recipe requirements. Regardless of the range of back helium pressure required by the process, the system can automatically adjust the helium flow rate to ensure the stability and reliability of the process. This enables the etching device to maintain good performance in different chip manufacturing processes, improves the versatility and process adaptability of the equipment, reduces the errors that may be caused by manual parameter adjustment by operators, and improves production efficiency. This automated control method not only improves the stability of the etching process, but also facilitates process management and optimization, providing a strong guarantee for the large-scale production of high-quality chips.

[0102] Similarly, although argon is an inert gas and does not directly participate in the etching reaction, its flow rate will affect the ratio of process gases. Excessive introduction of argon will dilute the concentration of other process gases involved in the reaction, thereby changing the chemical balance and reactivity of the entire process gas, and having a negative impact on process results such as etching rate and etching uniformity. If the argon flow rate is too small, its ability to block process gases from contacting the back of the wafer due to its larger atomic mass will be insufficient, and it will not be able to effectively push away the process gas on the back of the wafer, resulting in the back of the wafer still being etched.

[0103] Based on a large number of tests and verifications, it is found that when the process gas is a fluorine-based gas, changes in the total fluorine-based ratio in the process gas will cause changes in the reactivity and diffusion characteristics of the process gas. For example, fluorine-based gases usually have a higher reactivity during etching, and different ratios will result in different requirements for argon gas to block the process gas from sinking. At the same time, changes in the total intake volume of the process gas will change the overall flow rate and pressure distribution of the gas in the chamber.

[0104] In simple terms, the total intake volume of process gas (A) and the total proportion of fluorine-based gas in the process gas (B) have a specific relationship with the required argon flow rate (C).

[0105] Therefore, according to the total process gas intake volume and the total F-based ratio set by the UI in the recipe, the system can automatically adjust the argon flow rate of the second gas flow channel 10b according to the predetermined rules to meet the precise requirements for the argon flow rate under different process conditions. The comparison table is as follows (this table is applicable to ICP processes below 10mTorr):

[0106] Specifically, when the process gas is a fluorine-based gas, when the total intake volume of the process gas A is less than 100 SCCM, if the fluorine-based proportion B is less than 30%, the argon flow rate C of the second air flow channel 10b is 0.4AB; when the total intake volume of the process gas A is less than 100 SCCM, if the fluorine-based proportion is 30%≤B≤70%, the argon flow rate C of the second air flow channel 10b is 0.5AB; when the total intake volume of the process gas A is less than 100 SCCM, if the fluorine-based proportion B is greater than 70%, the argon flow rate C of the second air flow channel 10b is 0.6AB.

[0107] When the total intake volume of process gas is 100SCCM≤A≤200SCCM, if the fluorine-based proportion B is less than 30%, the argon flow rate C of the second air flow channel 10b is 0.2AB; when the total intake volume of process gas is 100SCCM≤A≤200SCCM, if the fluorine-based proportion is 30%≤B≤70%, the argon flow rate C of the second air flow channel 10b is 0.3AB; when the total intake volume of process gas is 100SCCM≤A≤200SCCM, if the fluorine-based proportion B is greater than 70%, the argon flow rate C of the second air flow channel 10b is 0.4AB.

[0108] When the total intake volume of process gas A>200SCCM, if the fluorine-based proportion B<30%, the argon flow rate C of the second air flow channel 10b is 0.1AB; when the total intake volume of process gas A>200SCCM, if the fluorine-based proportion is 30%≤B≤70%, the argon flow rate C of the second air flow channel 10b is 0.2AB; when the total intake volume of process gas A>200SCCM, if the fluorine-based proportion B>70%, the argon flow rate C of the second air flow channel 10b is 0.3AB.

[0109] In one specific embodiment, the process gas is 50 (SCCM) CF 4 +100 (SCCM) CHF 3 , among which, the F group accounts for 66.67% and the total gas volume is 150SCCM; at this time, the ventilation volume of argon gas is 0.3*150*66.67%=30SCCM.

[0110] The argon flow rate is precisely controlled according to the total intake volume of process gas and the fluorine-based ratio, ensuring that the process gas can maintain a suitable ratio under various conditions. This helps to maintain the chemical balance and reaction activity of the etching reaction within the ideal range, making the process parameters such as etching rate and etching depth more stable and controllable. For example, when the fluorine-based ratio is low, the argon flow rate is appropriately reduced to avoid excessive dilution of the process gas and ensure that the etching reaction can proceed at an appropriate rate; when the fluorine-based ratio is high, the argon flow rate is increased to prevent excessive etching or uneven etching caused by excessive activity of fluorine-based gas. Accurately controlling the argon flow rate ensures that under different process conditions, there is enough argon to form an effective barrier layer on the back of the wafer. When the total intake volume of process gas and the fluorine-based ratio change, the correspondingly adjusted argon flow rate can always effectively push away the process gas on the back of the wafer to prevent the back of the wafer from being etched. This is crucial to improving the quality and integrity of the wafer, helping to improve the yield rate of chip manufacturing and reduce product scrapping caused by back etching.

[0111] The automatic control scheme can adapt to a variety of different process conditions. Whether the total process gas intake is low, moderate or high, and the fluorine-based ratio is in different ranges, it can give a suitable argon flow control strategy. This enables the etching process to maintain good performance when facing different chip manufacturing requirements, improves the adaptability of the equipment to various process recipes, enhances the versatility of the equipment, and reduces the cost of equipment re-commissioning due to process adjustments. Through the automatic argon flow control, the errors and uncertainties that may be caused by manual intervention are reduced. The system can automatically adjust the argon flow according to the real-time process parameters to ensure that the ratio of process gas and the protection of the back of the wafer are always in the best state during the entire etching process. This greatly improves the stability and reliability of the etching process, so that each batch of chip manufacturing can obtain relatively consistent process results, which is conducive to the large-scale production of high-quality chips. Accurate argon flow control avoids process problems caused by improper argon flow, such as uneven etching, back etching, etc., and reduces the defective rate and rework times. At the same time, the automated control method saves the time of manual parameter adjustment, improves the continuity and efficiency of the production process, thereby reducing production costs and improving the production efficiency of enterprises.

[0112] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A wafer carrying mechanism for optimizing edge processing, characterized in that: include: A carrier (10), the carrier (10) comprising a mounting portion (11) and a supporting portion (12), the supporting portion (12) being arranged on the mounting portion (11), and the supporting portion (12) being used to support a wafer; an edge ring (20) disposed on the mounting portion (11), arranged in a ring shape and surrounding the supporting portion (12), with a gap between the edge ring (20) and the supporting portion (12), the gap being used as a gas operation channel; The surface diameter of the supporting portion (12) for contacting the wafer is smaller than the diameter of the wafer, and when the carrier (10) supports the wafer, the edge of the wafer protrudes from the supporting portion (12) and is exposed on the gas operation channel; The carrier (10) is provided with a first air flow channel (10a), one end of the first air flow channel (10a) is connected to the helium supply device, and the other end of the first air flow channel (10a) passes through the side of the supporting part (12) and is connected to the gas operation channel; The helium supply device is used to transport helium to the first air flow channel (10a). When the helium flows through the first air flow channel (10a), the carrier (10) can improve the temperature of the helium through heat conduction. The helium is blown toward the edge of the wafer through the first air flow channel (10a) and the gas operation channel. The helium can control the edge temperature of the wafer so as to balance the temperature of the entire wafer. The carrier (10) is further provided with a second air flow channel (10b), one end of the second air flow channel (10b) being connected to an argon gas supply device, and the other end of the second air flow channel (10b) passing through the top surface of the mounting portion (11) and being connected to the gas operation channel; The argon gas supply device is used to transport argon gas to the second gas flow channel (10b). The atomic mass of argon gas is greater than the atomic mass of the process gas. After the argon gas is blown into the gas operation channel through the second gas flow channel (10b), it can prevent the process gas from contacting the back side of the wafer, thereby preventing the back side of the wafer from reacting.

2. The wafer carrying mechanism for optimizing edge process according to claim 1, characterized in that: From top to bottom, the inner ring of the edge ring (20) is composed of a transition slope (21), a horizontal plane and a vertical plane (22), and the horizontal plane connects the transition slope (21) and the vertical plane (22) in series; The transition slope (21) extends obliquely toward the supporting portion (12); The horizontal plane is lower than the surface of the supporting portion (12) for contacting the wafer; There is a gap between the vertical plane (22) and the supporting portion (12), and the second airflow channel (10b) is directly opposite to the gap; The presence of the transition slope (21) can prevent the argon gas from rushing upwards and mixing with the process gas above the wafer to form laminar convection.

3. The wafer carrying mechanism for optimizing edge process according to claim 2, characterized in that: The vertical plane (22) is provided with an air chamber (23) near the bottom of the second air flow channel (10b); During the process, at least part of the argon gas can enter the gas chamber (23), and by reducing the flow rate, the pressure difference generated can drive the argon gas to flow upward along the gas operation channel.

4. The wafer carrying mechanism for optimizing edge process according to claim 1, characterized in that: An exhaust channel (20a) is provided on the edge ring (20), one end of the exhaust channel (20a) is connected to the gas operation channel, and the other end of the exhaust channel (20a) passes through the outer wall of the edge ring (20); When the carrier (10) supports a wafer, the exhaust passage (20a) is adjacent to the wafer; After the argon gas is blown upwards to the back side of the wafer, it can flow out from the side through the exhaust channel (20a), thereby preventing the argon gas from continuing to flow upwards and disturbing the gas environment on the front side of the wafer.

5. The wafer carrying mechanism for optimizing edge process according to any one of claims 1 to 4, characterized in that: The carrier (10) comprises a metal base and a ceramic layer, wherein the ceramic layer covers the top of the metal base, and the ceramic layer is used to contact the wafer; The carrier (10) is further provided with a third air flow channel, one end of the third air flow channel being connected to a helium supply device and the other end of the third air flow channel penetrating the ceramic layer; During the process, helium is blown toward the back side of the wafer through the third air flow channel, which can improve the wafer temperature and, by monitoring the back helium pressure, confirm whether the wafer is adsorbed and fixed by the carrier (10).

6. An etching device, characterized in that: A wafer carrying mechanism for optimizing edge processing according to any one of claims 1 to 5, further comprising: A process chamber, wherein the wafer carrying mechanism is disposed in the process chamber, and the process chamber can provide space for wafer etching; A radio frequency power supply, connected to the carrier (10) and used to supply power to the carrier (10), so that the carrier (10) can fix the wafer by electrostatic adsorption after being powered on; A gas supply device, connected to the gas inlet of the process chamber, for delivering process gas to the process chamber; A molecular pump connected to the gas outlet of the process chamber and used to extract the gas in the process chamber; Wherein, the air inlet is arranged above the wafer supporting mechanism, and the air outlet is arranged below the wafer supporting mechanism.

7. The etching device according to claim 6, characterized in that: The carrier (10) is provided with a first airflow channel (10a), a second airflow channel (10b) and a third airflow channel; The etching device also includes: A first sensor, using MFC, for monitoring the helium flow in the first gas flow channel (10a); A second sensor, using MFC, for monitoring the flow rate of argon gas in the second gas flow channel (10b); The third sensor, using UPC, is used to monitor the helium pressure in the third air flow channel.

8. An etching method, characterized in that: The etching device according to claim 7 is used to implement the process, comprising the following steps: The carrier (10) supports the wafer; The radio frequency power supply applies an adsorption voltage to the carrier (10); The helium supply device delivers low-pressure helium to the third air flow channel. If the flow rate fed back by the third sensor is less than 1 SCCM, it indicates that the wafer has been adsorbed; Increasing the helium pressure delivered by the helium supply device to the third air flow channel to maintain stable heat dissipation; The helium supply device delivers helium to the first airflow channel (10a), and the two helium channels cooperate to control the temperature of the wafer; The argon gas supply device delivers argon gas to the second gas flow channel (10b); The gas supply device delivers process gas to the process chamber through the gas inlet; Complete etching; The gas supply equipment stops delivering process gas; The argon supply equipment stops delivering argon; The RF power supply stops supplying power; The helium supply device delivers low-pressure helium to the third gas flow channel. If the flow rate fed back by the third sensor increases, it indicates that the wafer has been desorbed; The helium supply stops delivering helium.

9. The etching method according to claim 8, characterized in that: When the third sensor detects that the back helium pressure is 3≤p<5Torr, the helium flow rate of the first air flow channel (10a) is adjusted to 1 SCCM; When the third sensor detects that the back helium pressure is 5≤p<8Torr, the helium flow rate of the first air flow channel (10a) is adjusted to 3SCCM; When the third sensor detects that the back helium pressure is 8≤p<10Torr, the helium flow rate of the first air flow channel (10a) is adjusted to 5 SCCM; When the third sensor detects that the back helium pressure is 10≤p<12Torr, the helium flow rate of the first air flow channel (10a) is adjusted to 8 SCCM; When the third sensor detects that the back helium pressure p≥12 Torr, the helium flow rate of the first air flow channel (10a) is adjusted to 10 SCCM.

10. The etching method according to claim 8, characterized in that: The process gas is fluorine-based gas; When the total process gas intake volume A is less than 100 SCCM, if the fluorine-based ratio B is less than 30%, the argon gas flow rate C of the second gas flow channel (10b) is 0.4AB; When the total process gas intake volume A is less than 100 SCCM, if the fluorine-based ratio is 30%≤B≤70%, the argon gas flow rate C of the second gas flow channel (10b) is 0.5AB; When the total process gas intake volume A is less than 100 SCCM, if the fluorine-based ratio B is greater than 70%, the argon gas flow rate C of the second gas flow channel (10b) is 0.6AB; When the total intake volume of the process gas is 100 SCCM≤A≤200 SCCM, if the fluorine-based ratio B is less than 30%, the argon gas flow rate C of the second gas flow channel (10b) is 0.2AB; When the total intake volume of the process gas is 100 SCCM≤A≤200 SCCM, if the fluorine-based ratio is 30%≤B≤70%, the argon gas flow rate of the second gas flow channel (10b) is C=0.3AB; When the total intake volume of process gas is 100 SCCM≤A≤200 SCCM, if the fluorine-based ratio B>70%, the argon gas flow rate C of the second gas flow channel (10b) is 0.4AB; When the total process gas intake volume A>200 SCCM, if the fluorine-based ratio B<30%, the argon gas flow rate C of the second gas flow channel (10b) is 0.1AB; When the total process gas intake volume A>200 SCCM, if the fluorine-based ratio is 30%≤B≤70%, the argon gas flow rate C of the second gas flow channel (10b) is 0.2AB; When the total process gas intake volume A>200 SCCM, if the fluorine-based ratio B>70%, the argon gas flow rate C of the second gas flow channel (10b) is 0.3AB.

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