Wafer Carrying Mechanism, Etching Device and Etching Method for Optimizing Edge Process

Abstract

The present application discloses a wafer carrier mechanism, an etching device and an etching method for optimizing the edge process. The wafer carrier mechanism includes a carrier and an edge ring. The carrier includes a mounting portion and a supporting portion. There is a gas operation channel between the edge ring and the supporting portion. The carrier is provided with a first gas flow channel and a second gas flow 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 backside of the wafer from being alienated, thereby optimizing the edge process and improving the overall process level. The etching device includes a wafer carrier mechanism, a process chamber, a radio frequency power supply, a gas supply device and a molecular pump. Each component works together to provide a stable environment for the etching reaction. The etching method is realized by the above-mentioned etching device. The optimized process control makes the etching process more stable and controllable, which helps to improve production efficiency, reduce production costs and meet the requirements of different chip manufacturing processes.

Description

Technical Field

[0001] This application relates to the technical field of wafer etching, and in particular to a wafer carrier mechanism, an etching device, and an etching method for optimizing edge processes. 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 accumulates in the vacuum chamber, which can excite gas discharge to form plasma, enabling positively charged ions to bombard the wafer surface, thereby removing natural oxides or carbon fluoride residues on the wafer surface, and finally etching the desired shape on the wafer surface.

[0003] In a traditional etching chamber, for the convenience of wafer transfer, adsorption, 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 results in the edge of the wafer exceeding the carrier. There is a temperature difference between the temperature of the exceeding edge part and the central 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 cause glue paste; moreover, for the etching of PR / PI, fluorine - based gases such as CHF3 and CF4 are introduced as process gases, which will cause the back side of the wafer edge exceeding the carrier to be etched. Especially in a long - term process, severe back - side etching will reduce the thickness of this part of the wafer and generate excess polymer adhering to the back side of the wafer. In subsequent processes, the too - thin wafer will increase the risk of fragmentation, and excessive polymer adhesion will affect the results of subsequent processes and reduce the product yield. Summary of the Invention

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

[0005] The present application provides a wafer carrier mechanism for optimizing edge processes, characterized by comprising: a carrier, which includes a mounting portion and a supporting portion, the supporting portion is provided on the mounting portion, and the supporting portion is used to support the wafer; an edge ring, which is provided 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 for contacting the wafer is smaller than the diameter of the wafer. When the carrier supports the wafer, the edge of the wafer protrudes from the supporting portion and is exposed in the gas operation channel; a first gas flow channel is provided in the carrier, one end of the first gas flow channel communicates with a helium supply device, and the other end penetrates through the side surface of the supporting portion and communicates with the gas operation channel; the helium supply device is used to convey helium to the first gas flow channel. When helium flows through the first gas flow channel, the carrier can improve the temperature of helium through heat conduction; a second gas flow channel is also provided in the carrier, one end of the second gas flow channel communicates with an argon supply device, and the other end penetrates through the top surface of the mounting portion and communicates with the gas operation channel; the argon supply device is used to convey argon to the second gas flow channel. The atomic mass of argon is greater than that of the process gas. After argon is blown into the gas operation channel through the second gas flow channel, it can prevent the process gas from contacting the back surface of the wafer; during the process treatment, helium is blown towards the edge of the wafer through the first gas flow channel and the gas operation channel to control the temperature of the edge of the wafer, so as to achieve temperature balance of the whole wafer; argon is blown towards the back surface of the wafer through the second gas flow channel and the gas operation channel, thereby preventing reactions from occurring on the back surface of the wafer.

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

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

[0008] Further, an exhaust channel is provided on the edge ring, one end of the exhaust channel communicates with the gas operation channel, and the other end penetrates through the outer wall of the edge ring; when the carrier supports the wafer, the exhaust channel is close to the wafer; after argon blows upwards on the back surface of the wafer, it can flow out from the side through the exhaust channel, thereby preventing argon from continuing to flow upwards and interfering with the gas environment on the front surface 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 monitors that the back helium pressure satisfies 3 ≤ p < 5 Torr, the helium gas flow rate in the first gas flow channel is adjusted to 1 SCCM; when the third sensor monitors that the back helium pressure satisfies 5 ≤ p < 8 Torr, the helium gas flow rate in the first gas flow channel is adjusted to 3 SCCM; when the third sensor monitors that the back helium pressure satisfies 8 ≤ p < 10 Torr, the helium gas flow rate in the first gas flow channel is adjusted to 5 SCCM; when the third sensor monitors that the back helium pressure satisfies 10 ≤ p < 12 Torr, the helium gas flow rate in the first gas flow channel is adjusted to 8 SCCM; when the third sensor monitors that the back helium pressure p ≥ 12 Torr, the helium gas flow rate in the first gas flow channel is adjusted to 10 SCCM.

[0014] Further, the process gas is a fluorine-based gas; when the total inlet gas volume A of the process gas is less than 100 SCCM, if the fluorine-based gas proportion B is less than 30%, the argon gas flow rate C in the second gas flow channel is 0.4AB; when the total inlet gas volume A of the process gas is less than 100 SCCM, if the fluorine-based gas proportion satisfies 30% ≤ B ≤ 70%, the argon gas flow rate C in the second gas flow channel is 0.5AB; when the total inlet gas volume A of the process gas is less than 100 SCCM, if the fluorine-based gas proportion B is greater than 70%, the argon gas flow rate C in the second gas flow channel is 0.6AB;

[0015] When the total inlet gas volume A of the process gas satisfies 100 SCCM ≤ A ≤ 200 SCCM, if the fluorine-based gas proportion B is less than 30%, the argon gas flow rate C in the second gas flow channel is 0.2AB; when the total inlet gas volume A of the process gas satisfies 100 SCCM ≤ A ≤ 200 SCCM, if the fluorine-based gas proportion satisfies 30% ≤ B ≤ 70%, the argon gas flow rate C in the second gas flow channel is 0.3AB; when the total inlet gas volume A of the process gas satisfies 100 SCCM ≤ A ≤ 200 SCCM, if the fluorine-based gas proportion B is greater than 70%, the argon gas flow rate C in the second gas flow channel is 0.4AB;

[0016] When the total inlet gas volume A of the process gas is greater than 200 SCCM, if the fluorine-based gas proportion B is less than 30%, the argon gas flow rate C in the second gas flow channel is 0.1AB; when the total inlet gas volume A of the process gas is greater than 200 SCCM, if the fluorine-based gas proportion satisfies 30% ≤ B ≤ 70%, the argon gas flow rate C in the second gas flow channel is 0.2AB; when the total inlet gas volume A of the process gas is greater than 200 SCCM, if the fluorine-based gas proportion B is greater than 70%, the argon gas flow rate C in the second gas flow channel is 0.3AB.

[0017] The present application provides a wafer carrier mechanism for optimizing edge processes, including a carrier and an edge ring. The carrier includes a mounting portion and a supporting portion. There is a gas operation channel between the edge ring and the supporting portion. The carrier is provided with a first gas flow channel and a second gas flow channel. The first gas flow channel communicates with a helium supply device and the gas operation channel, and the second gas flow channel communicates with an argon supply device and the gas operation channel. The gas operation channel cooperates with the first and second gas flow channels. Helium can control the edge temperature of the wafer, and argon can effectively prevent the backside of the wafer from being alienated, thereby optimizing the edge process and improving the overall process level. In the wafer carrier mechanism provided by the present application, the positional relationships of the components are clear, the cooperation method is scientific, the gas operation channel, the first gas flow channel, and the second gas flow channel are reasonably designed, realizing the effective delivery and function of helium and argon, and ensuring the stability and reliability of the operation of the entire mechanism. At the same time, the present application makes full use of the heat conduction performance of helium and the atomic mass and inert gas characteristics of argon, and solves key problems such as wafer edge temperature control and backside alienation without affecting the normal process, having high practicability and innovation.

[0018] The present application also provides an etching device, including the above-mentioned wafer carrier mechanism, and further 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 transport process gases into the process chamber through an air inlet, and the molecular pump can extract the gases in the chamber through an 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 gases 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. Each component of the etching device provided by the present application works 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, all contribute to maintaining the stability of various parameters during the etching process, improving the repeatability and controllability of the etching process, and being conducive to large-scale production of high-quality chips.

[0019] The present application also provides an etching method, which is realized by the above-mentioned etching device. The entire etching method precisely controls various links such as the supply of each gas, the adsorption and desorption of the wafer, etc., and each step is closely coordinated. This optimized process control makes the etching process more stable and controllable, helps to improve production efficiency, reduce production costs, and meet the requirements of different chip manufacturing processes. Description of the Drawings

[0020] Figure 1 is a schematic structural diagram of an etching device provided by the present application;

[0021] Figure 2 is Figure 1 an enlarged view of the structure within the circle in DETAILED DESCRIPTION

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] Continue to refer to Figure 1, the edge ring 20 is generally in the shape of a thick-walled cylinder. The edge ring 20 is fixedly arranged on the mounting part 11 and encloses the supporting part 12 within it. There is a gap between the edge ring 20 and the supporting part 12, and gas can flow through the gap. Therefore, the gap serves as a gas operation channel. The gas operation channel is also in the shape of a cylinder. The edge ring 20 is slightly higher than the supporting part 12. When the supporting part 12 supports the wafer, the wafer is confined within the edge ring 20, and the edge ring 20 has the functions of limiting and protecting.

[0027] Optionally, the edge ring 20 is made of ceramic. Ceramic has insulating properties and can adjust the electric field and plasma distribution in the edge area of the wafer during etching.

[0028] In a plasma environment, the etching rate and uniformity at the edge of the wafer often differ from those in the central area. Through its special material and structural characteristics, the edge ring 20 can optimize the interaction between the plasma in the edge area and the wafer surface, making the etching conditions in the edge area closer to those in the central area, thereby improving the etching uniformity.

[0029] Specifically, a first gas flow channel 10a is provided in the carrier 10. One end of the first gas flow channel 10a is connected to a helium supply device, and the other end penetrates the side surface of the supporting part 12 and is connected to the gas operation channel; the helium supply device is used to supply helium to the first gas flow channel 10a. When helium flows through the first gas flow channel 10a, the carrier 10 can improve the temperature of helium through heat conduction; a second gas flow channel 10b is also provided in the carrier 10. One end of the second gas flow channel 10b is connected to an argon supply device, and the other end penetrates the top surface of the mounting part 11 and is connected to the gas operation channel; the argon supply device is used to supply argon to the second gas flow channel 10b. The atomic mass of argon is greater than that of the process gas. After argon is blown into the gas operation channel through the second gas flow channel 10b, it can prevent the process gas from contacting the back surface of the wafer; during the process treatment, helium is blown towards the edge of the wafer through the first gas flow channel 10a and the gas operation channel to control the temperature of the edge of the wafer, so as to achieve temperature balance of the whole wafer; argon is blown towards the back surface of the wafer through the second gas flow channel 10b and the gas operation channel, thereby preventing reactions from occurring on the back surface of the wafer.

[0030] Specific reference can be made to Figure 1 and Figure 2 , in the illustrated embodiment, a gas operation channel is formed between the edge ring 20 and the supporting part 12. The top end of the gas operation channel is open, the bottom end 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 part 12 and be in the gas operation channel.

[0031] Continue to refer to Figure 1 and Figure 2, the vehicle 10 is provided with a first air flow channel 10a and a second air flow channel 10b. The lower end of the first air flow channel 10a penetrates through the bottom surface of the mounting portion 11 and is used to communicate with the helium supply device, and the upper end of the first air flow channel 10a penetrates through the side surface of the supporting portion 12 and communicates with the gas operation channel. The lower end of the second air flow channel 10b penetrates through the bottom surface of the mounting portion 11 and is used to communicate with the argon supply device, and the upper end of the second air flow channel 10b penetrates through the top surface of the mounting portion 11 and is used to communicate with the helium supply device.

[0032] It is easy to understand that since the central region of the wafer will contact the supporting portion 12, the vehicle 10 can directly conduct heat to this region, so as to ensure that this region maintains the process temperature. However, the edge region of the wafer is outside the supporting portion 12, resulting in that this part of the region cannot directly conduct heat with the vehicle 10. Therefore, the edge region of the wafer often cannot be at the process temperature.

[0033] By adding the first air flow channel 10a, during the process treatment, helium can exchange heat with the vehicle 10 when flowing through the first air flow channel 10a; due to the excellent heat conduction performance of helium (helium atom is the second lightest atom after hydrogen atom, and the thermal conductivity is 0.1682 W / m·°C), when flowing through the first air flow channel 10a, the vehicle 10 can adjust the temperature of helium through heat conduction, so that helium quickly reaches the process temperature; then, helium is blown towards the edge of the wafer through the gas operation channel. Heat is quickly transferred between helium and the edge of the wafer, so as to effectively control the temperature of the part of the wafer beyond the supporting portion 12, ensure the overall temperature balance of the wafer, and avoid affecting the process effect due to uneven temperature.

[0034] When performing surface treatment processes (such as etching, coating, etc.) on the wafer, process gases are also introduced into the process chamber, and the relevant processes are realized by ionizing the process gases and generating plasma. When the process gases move in the process chamber, they may move downward and contact the back surface of the wafer, resulting in reactions on the back surface and abnormal states.

[0035] By adding the second air flow channel 10b, during the process treatment, after argon passes through the second air flow channel 10b and is blown into the gas operation channel, due to its large atomic mass and large kinetic energy, a blocking layer will be formed in the gas operation channel; when the process gas particles move to the gas operation channel, the argon particles will collide with them and push them away, making it difficult for the process gases to contact the back surface of the wafer. At the same time, as an inert gas, argon has basically no influence on the process except for changing the gas ratio; therefore, choosing argon as the back surface protection gas will neither affect the normal process nor effectively prevent the occurrence of the phenomenon of back surface alienation of the wafer.

[0036] In short, by utilizing the high heat conduction performance of helium, it is possible to effectively and reliably control the temperature of the wafer edge, achieve the overall temperature balance of the wafer, thereby improving the stability of the wafer temperature and the controllability of environmental parameters during the process, and contributing to enhancing the accuracy and quality of processes such as etching. The use of argon can prevent the process gas from contacting the back side of the wafer, thus avoiding the occurrence of situations such as back side alienation of the wafer, ensuring the integrity of the wafer structure, and improving the yield rate of chip manufacturing.

[0037] In summary, by reserving a gas operation channel through the carrier 10 and the edge ring 20, and cooperating 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 alienation of the wafer, thereby optimizing the edge process and enhancing the overall process level; in the wafer carrying mechanism provided by the present application, the positional relationship of each component is clear, the cooperation method is scientific, the gas operation channel, the first air flow channel 10a and the second air flow channel 10b are reasonably designed, realizing the effective delivery and function exertion of helium and argon, and ensuring the stability and reliability of the operation of the whole mechanism; at the same time, the present application makes full use of the heat conduction performance of helium and the atomic mass and inert gas characteristics of argon, and solves the key problems such as wafer edge temperature control and back side alienation without affecting the normal process, having high practicality and innovation.

[0038] 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 frustums, an installation part 11 and a supporting part 12; the edge ring 20 is generally in a thick-walled cylindrical shape, and the edge ring 20 is fixedly arranged on the installation part 11 and surrounds the supporting part 12 within its circle; a gas operation channel is formed between the edge ring 20 and the supporting part 12, and the gas operation channel is a vertically extending annular structure.

[0039] To facilitate the full entry of helium and argon into the annular gas operation channel, in one embodiment, the carrier 10 is provided with a plurality of first air flow channels 10a and a plurality of second air flow channels 10b. Taking the first air flow channel 10a as an example for illustration, the plurality of first air flow channels 10a are arranged at intervals in the circumferential direction, the lower end of each first air flow channel 10a communicates with the helium supply device, and the upper end communicates with the gas operation channel. The air outlet holes of these first air flow channels 10a point to different directions, so as to facilitate helium to flow into the gas operation channel from different directions, and further ensure that the edge area of the wafer can be fully blown by helium.

[0040] In another embodiment, an annular flow channel is provided near the outer peripheral wall inside the supporting portion 12 and near the top wall inside the mounting portion 11 respectively. The annular flow channel is a part of the first gas flow channel 10a and the second gas flow channel 10b. A plurality of small holes are evenly distributed along the circumference on the annular flow channel. Any one of the small holes penetrates the wall and communicates with the gas operation channel. These small holes are the air outlets of the first gas flow channel 10a and the second gas flow channel 10b. After helium and argon enter the annular flow channel from a single air inlet hole, 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 are preliminarily homogenized in the annular flow channel before entering the gas operation channel. In this way, helium and argon can enter the gas operation channel more comprehensively and evenly; the design of a single air inlet hole can also reduce problems such as sealing that may be brought by multiple air inlet holes.

[0041] In another embodiment, the first gas flow channel 10a and the second gas flow channel 10b are arranged in a spiral structure. Taking the first gas flow channel 10a as an example for illustration, starting from the air inlet hole, the first gas flow channel 10a spirally extends upward along the vertical direction to penetrate the side surface of the supporting portion 12. During the process of process treatment, when helium flows in the spiral channel, certain disturbances and mixing will be generated due to the special shape of the channel, which helps the gas to be more evenly distributed; the helium fed along the spiral path can more comprehensively cover the gas operation channel after entering the gas operation channel under the action of inertia. This embodiment uses the spiral structure to increase the gas flow path and mixing effect, and can also reduce the space occupied by the channel to a certain extent, so as to achieve more efficient gas delivery within the limited structure of the carrier 10.

[0042] Optionally, from bottom to top, the air outlet end of the first gas flow channel 10a communicating with the gas operation channel extends obliquely towards the gas operation channel, so as to facilitate helium to blow towards the edge of the wafer.

[0043] Specifically, reference can be made to Figure 2 , in the illustrated embodiment, the first gas 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 communicate with the helium supply device, and the upper end of the inclined air outlet section penetrates the side surface of the supporting portion 12 and communicates with the gas operation channel. From right to left, the inclined air outlet section extends upward. After 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.

[0044] When helium gas is ejected from the inclined gas outlet section, since the gas flow direction forms a certain angle with the wall surface of the gas operation channel and the edge of the wafer, a component velocity along the inclined gas outlet section and pointing towards the edge of the wafer will be generated. This enables the helium gas to rush towards the edge of the wafer more directly and efficiently after leaving the inclined gas outlet section. At the same time, the inclined gas outlet section can also change the flow field distribution after the helium gas is ejected, causing the helium gas to form a specific flow pattern within the gas operation channel, which helps it to come into contact with the edge of the wafer more fully within a limited space, achieving rapid heat transfer and effective temperature regulation.

[0045] The inclined gas outlet section enables the helium gas to blow towards the edge of the wafer more precisely, reducing the diffusion and loss of the helium gas during transmission, and enabling the heat carried by the helium gas to be transferred to the edge of the wafer more quickly. Compared with the vertical or horizontal gas outlet directions, this design can achieve temperature regulation of the edge of the wafer in a shorter time, which is beneficial to improving the temperature control efficiency and meeting the requirements of the process for rapid temperature response.

[0046] In addition, when the helium gas blows towards the edge of the wafer at a specific angle, a more uniform gas flow distribution will be formed in the edge area of the wafer. The uniform gas flow helps to achieve more uniform heat exchange at the edge of the wafer, avoiding temperature differences caused by uneven local gas flow, thereby making the overall temperature of the wafer more balanced, improving the uniformity of temperature control, being beneficial to improving the accuracy and consistency of processes such as etching, and reducing process deviations caused by uneven temperature.

[0047] Optionally, from bottom to top, the second gas flow channel 10b extends vertically towards the gas operation channel to facilitate the argon gas from obstructing the process gas from entering the gas operation channel from top to bottom.

[0048] During the process treatment, due to factors such as gravity and gas flow in the chamber, the process gas has a tendency to enter the gas operation channel from top to bottom and contact the back surface of the wafer. By setting the second gas flow channel 10b to extend vertically towards the gas operation channel, the argon gas can be ejected vertically upwards. Based on the principle of gas dynamics, argon gas has a relatively large atomic mass, and after being ejected, it forms a vertically upward gas flow column. When the process gas moves downwards, it will meet the vertically upward argon gas flow column. This vertical gas flow distribution can oppose the process gas moving from top to bottom to the greatest extent, greatly improving the blocking efficiency of the process gas and effectively preventing the process gas from entering the gas operation channel to contact the back surface of the wafer.

[0049] Optionally, from top to bottom, the inner ring of the edge ring 20 is composed of a transition inclined surface 21, a horizontal plane, and a vertical plane 22. The horizontal plane connects the transition inclined surface 21 and the vertical plane 22 in series. The transition inclined surface 21 extends obliquely towards 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 gas flow channel 10b is opposite to the gap. The existence of the transition inclined surface 21 can prevent argon from flushing straight up, mixing with the process gas above the wafer, and forming a laminar convection.

[0050] For specific reference, Figure 2 , in the illustrated embodiment, the right side of the edge ring 20 facing the supporting portion 12 is its inner ring. From top to bottom, the inner ring of the edge ring 20 is sequentially connected by a transition inclined surface 21, a horizontal plane, and a vertical plane 22. Since the edge ring 20 is an annular structure, the upper end of the edge ring 20 where the transition inclined surface 21 is located is roughly in a tapered horn shape. 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 inclined surface 21 and the wafer.

[0051] When the process gas flows downward and the argon flows upward, the two directly impact vertically, which easily causes gas mixing and forms a laminar convection. The laminar convection will change the original concentration, distribution, and reaction activity of the process gas, and further interfere with the normal progress of the process.

[0052] The design of the transition inclined surface 21 can change the flow direction of argon. According to the principle of fluid mechanics, gas tends to flow along the solid surface. Therefore, during the upward flow of argon, when it encounters the transition inclined surface 21, the argon will change its flow path along the inclined direction of the transition inclined surface 21. In this way, the argon no longer flushes straight up vertically, which reduces the possibility of direct mixing with the process gas and forming a laminar convection.

[0053] By preventing the generation of laminar convection, the stability of the process gas can be ensured, providing a stable environment for the process reaction, and helping to improve the surface treatment effect.

[0054] At the same time, the combination of the horizontal plane and the vertical plane 22 further guides and restricts the flow of argon, making it form a stable and effective blocking air flow in the gas operation channel, and finally reliably preventing the process gas from sinking.

[0055] Optionally, an air chamber 23 is provided at the bottom of the vertical plane 22 close to the second gas flow channel 10b. During the process treatment, at least part of the argon can enter the air chamber 23. By reducing the flow rate, the generated pressure difference can drive the argon to flow upward along the gas operation channel.

[0056] For specific reference, Figure 2, in the illustrated embodiment, on the right side of the edge ring 20 and close to the bottom of the mounting portion 11, there is an air chamber 23 recessed to the left. The cross-section of the air chamber 23 is trapezoidal, and the air chamber 23 has a certain volume.

[0057] During the process treatment, argon enters the gas operation channel from bottom to top, and part of the argon directly enters the air chamber 23. According to the principle of fluid mechanics, when the gas enters the relatively wide air chamber 23 from the relatively narrow second gas flow channel 10b), due to the sudden increase in the flow area, the gas flow rate will decrease rapidly. According to Bernoulli's principle, in the process of fluid flow, the flow rate is inversely proportional to the pressure. Therefore, when the flow rate of argon in the air chamber 23 decreases, the pressure in the air chamber 23 will relatively increase, while the pressure in the gas operation channel above the air chamber 23 will relatively decrease, thus forming a pressure difference between the air chamber 23 and the gas operation channel. This pressure difference can serve as a driving force to promote the argon in the air chamber 23 to flow upward along the gas operation channel, further enhancing the blocking gas flow formed by argon in the gas operation channel, thereby efficiently preventing the process gas from contacting the back surface of the wafer downward.

[0058] Optionally, the edge ring 20 is provided with an exhaust channel 20a. One end of the exhaust channel 20a communicates with the gas operation channel, and the other end penetrates through the outer wall of the edge ring 20; when the carrier 10 holds the wafer, the exhaust channel 20a is close to the wafer; after the argon blows the back surface of the wafer upward, it can flow out from the side through the exhaust channel 20a, thus preventing the helium from continuing to flow upward and interfering with the gas environment on the front surface of the wafer.

[0059] Specifically, reference can be made to Figure 2 , in the illustrated embodiment, from top to bottom, the inner ring of the edge ring 20 is sequentially connected by a transition inclined surface 21, a horizontal plane, and a vertical plane 22. The upper part of the edge ring 20 is provided with an exhaust channel 20a, and the exhaust channel 20a extends horizontally. The right end of the exhaust channel 20a penetrates through the transition inclined surface 21, and the left end penetrates through the outer wall of the outer ring of the edge ring 20. When the carrier 10 holds the wafer, the right end of the exhaust channel 20a faces the wafer.

[0060] It is easy to understand that when the exhaust channel 20a is not provided, the argon will continue to diffuse upward after being blown upward, which may interfere with the gas environment on the front surface of the wafer and affect the process on the front surface. According to the basic principle of gas flow, gas always tends to flow from a high-pressure area to a low-pressure area. The other end of the exhaust channel 20a penetrates through the outer wall of the edge ring 20 and is closer to the outlet of the process chamber than the inlet of the process chamber, so that the pressure in the exhaust channel 20a is less than the pressure in the gas operation channel and above the wafer where the process gas is located. Under the action of the natural flow of the gas and the small pressure difference existing inside and outside the channel diffusion, the argon will preferentially flow out through the exhaust channel 20a.

[0061] Similarly, helium will also preferentially flow out through the exhaust channel 20a instead of flowing upward to interfere with the gas environment on the front side of the wafer.

[0062] Optionally, multiple sets of exhaust channels 20a are provided on the edge ring 20, and the multiple sets of exhaust channels 20a are spaced apart along the circumferential direction to facilitate the rapid and uniform outflow of helium and argon in the gas operation channel.

[0063] Optionally, the cross-sectional area of the exhaust channel 20a gradually increases along the gas flow direction. Specifically, at the entrance where the exhaust channel 20a is connected to the gas operation channel, the cross-sectional area of the channel is small, and as the channel extends towards the outer wall of the edge ring 20, the cross-sectional area gradually becomes larger. According to the principle of fluid mechanics, when 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-section design makes it easier for 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 gradually decreasing pressure, a suction effect will be formed, accelerating the speed of the gas entering the exhaust channel 20a from the gas operation channel. At the same time, the larger outlet cross-section helps the gas to be quickly discharged. Thus, the exhaust performance can be optimized without increasing the number of exhaust channels 20a or complicating the structure of the exhaust channels 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 volumes, and can improve the stability of the equipment under different process conditions.

[0064] Optionally, the height of the exhaust channel 20a is lower the farther away from the gas operation channel, so as to promote the downward movement of the outflowing helium and argon and keep them away from the front side of the wafer.

[0065] Specifically, when helium and argon flow from the gas operation channel into the exhaust channel 20a, due to the gradually decreasing height of the exhaust channel, the gravitational component of the gas in the vertical direction gradually increases when the gas flows in the exhaust channel 20a. According to the action of gravity, the gas naturally has a tendency to move downward. At the same time, as the height of the exhaust channel 20a decreases, the gas flow space becomes smaller, and the gas flow rate will increase accordingly. According to the principle of fluid continuity, 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, and this pressure difference will further push the gas to flow towards the channel outlet. Under the guidance of the decreasing trend of the height of the exhaust channel 20a, the gas is more inclined to move downward. At this time, the flowing helium and argon will move downward along the trend of the exhaust channel 20a, which can effectively prevent the gas from approaching the front side of the wafer due to disordered flow during the exhaust process, greatly enhancing the control ability of the gas flow direction, ensuring that the process gas environment on the front side 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 inside the equipment more reasonable, avoids the accumulation of gas in local areas, and helps to maintain the stability of the overall gas environment inside the equipment.

[0066] Optionally, when the supporting part 12 supports the wafer, the exhaust channel 20a is directly opposite to the wafer. In this way, the argon purged from the back side of the wafer and the helium overflowing from the edge of the wafer can directly enter the exhaust channel 20a along the shortest path. Compared with the non-directly opposite design, the gas does not need to make complex turns or long-distance detours in the channel, greatly reducing the residence time of the gas in the gas operation channel and significantly accelerating the exhaust speed. Since the gas can be quickly exhausted, it can also effectively avoid the accumulation of gas in the area near the wafer. In processes such as etching, the accumulation of gas may change the local gas concentration and pressure, thereby affecting the stability and uniformity of the plasma. The design that the exhaust channel 20a is directly opposite to the wafer ensures that the gas can be exhausted in time, preventing this adverse situation from occurring and ensuring the accuracy and consistency of the process.

[0067] The exhaust channel 20a directly opposite to the wafer can more effectively capture the 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-side process can be quickly exhausted, guaranteeing the accuracy of the front-side process and helping to improve the yield of chip manufacturing.

[0068] Optionally, the carrier 10 includes a metal base and a ceramic layer. The ceramic layer covers the top of the metal base and is used to contact the wafer. A third gas flow channel is also provided in the carrier 10. One end of the third gas flow channel communicates with a helium supply device, and the other end penetrates through the ceramic layer. During the process treatment, helium is blown towards the back surface of the wafer through the third gas 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.

[0069] Specifically, a first gas flow channel 10a, a second gas flow channel 10b, and a third gas flow channel are provided in the carrier 10. The first gas flow channel 10a and the second gas flow channel 10b penetrate through the metal base, and one end of the third gas flow channel penetrates through the metal base and the other end extends to penetrate through the ceramic layer.

[0070] In the surface treatment process, temperature is an important environmental condition. As can be seen from the above, the carrier 10 can directly adjust the temperature of the wafer through heat conduction. By adding a third gas flow channel, during the process treatment, helium can be blown towards the back surface of the wafer through the third gas flow channel. Multiple groups of third gas flow channels can be set in the carrier 10, such as setting multiple circles of third gas flow channels along the diameter direction to facilitate the comprehensive purging of the wafer by helium. Or, multiple radially extending and radially distributed air guide grooves can be provided on the ceramic surface, and helium can comprehensively purge the back surface of the wafer along the air guide grooves. Since helium has excellent heat conduction performance, when helium flows through the third gas flow channel, it will obtain the process temperature under the influence of the carrier 10, and when purging the back surface of the wafer, helium will conduct heat with the wafer, thereby stabilizing the temperature of the wafer.

[0071] Since the ceramic layer covers the top of the metal base, the ceramic has certain heat insulation performance, which can reduce the heat dissipation to other parts of the carrier 10, so that the heat transferred by helium can act more concentratedly on the wafer, thereby effectively adjusting the temperature of the wafer, ensuring that the wafer maintains the process temperature during the process, and thus meeting the strict requirements of different processes for temperature.

[0072] In processes such as etching and lithography, minor fluctuations in temperature may affect the accuracy and effect of the process. By setting the third gas flow channel, a stream of helium can be introduced to assist the carrier 10 in controlling the temperature of the wafer, and better achieve precise adjustment of the wafer temperature. Precise temperature control helps to ensure the consistency of the etching rate, the accuracy of the lithography pattern, etc., which is beneficial to improving the yield of chip manufacturing and enhancing the overall process quality. At the same time, the heat insulation effect of the ceramic layer further enhances the accuracy of temperature control, avoiding unnecessary heat dissipation, and enabling the heat to act more effectively on the wafer.

[0073] When purging the back side of the wafer with helium gas, a pressure area, i.e., the back helium pressure, will be 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 within 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 gas within this gap are also relatively stable. However, if the wafer is not properly adsorbed, for example, there is local warping or incomplete fitting, then the gap between the wafer and the ceramic layer will change, and the flow resistance of helium gas will also change, thereby causing the back helium pressure to fluctuate or deviate from the normal range. By monitoring the change of the back helium pressure in real time, it is possible to determine whether the wafer is adsorbed and fixed by the carrier 10.

[0074] Using the back helium pressure to confirm whether the wafer is adsorbed and fixed provides a real-time monitoring means for the process. During 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 or is not firmly adsorbed during the process, it may lead to serious problems such as uneven etching and pattern deviation. By monitoring the back helium pressure in real time, once the pressure is abnormal, the operator can immediately take measures, such as readjusting the adsorption parameters or checking the equipment status, to avoid process failures caused by wafer adsorption problems and ensure the stability and continuity of the entire process.

[0075] The carrier 10 realizes both temperature control and back helium pressure monitoring by adding a third gas flow channel. This multi-functional design effectively simplifies the overall structure of the equipment. Compared with the traditional separate setting of a temperature control system and an adsorption monitoring system, it reduces the number of components and complexity inside the equipment, lowers the manufacturing cost and maintenance difficulty of the equipment. At the same time, the simplified structure also helps to improve the operating stability of the equipment and reduce the possible failure points due to excessive components.

[0076] This application also provides an etching device, which includes the wafer carrying mechanism for optimizing the edge process as described above, and further includes: a process chamber, the wafer carrying 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, for supplying power to the carrier 10, and after the carrier 10 is powered on, it can electrostatically adsorb and fix the wafer; a gas supply device, connected to the air inlet of the process chamber, for delivering process gas to the process chamber; a molecular pump, connected to the air outlet of the process chamber, for pumping out the gas in the process chamber; wherein, the air inlet is arranged above the wafer carrying mechanism, and the air outlet is arranged below the wafer carrying mechanism.

[0077] Specifically, reference can be made to Figure 1, in the illustrated embodiment, the process chamber is a relatively sealed cavity, and the carrier 10 is disposed at the bottom of the process chamber. The RF power supply is disposed outside the process chamber and is 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 a gas 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 a molecular pump through a pipeline.

[0078] The gas supply device conveys process gas into the process chamber through the air inlet. Optionally, a coil is further provided in the process chamber. The coil 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. During this process, structures such as the edge ring 20 and the gas flow channel of the wafer carrier mechanism cooperate to optimize the edge process and ensure the uniformity and accuracy of etching. The air inlet is provided above the carrier 10, so that the process gas can evenly cover the processing space from top to bottom, providing necessary reactants for etching. At the same time, the molecular pump extracts the gas in the chamber through the air outlet below. With such a setting, a gas flow path from top to bottom is formed, which is beneficial 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.

[0079] 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 charges on the back of the wafer by dividing the positive and negative poles, so that an electrostatic field is generated on the surface of the carrier 10, thereby being able to firmly adsorb the wafer and ensure that the wafer maintains a stable position during the etching process, avoiding etching deviation caused by displacement.

[0080] Specifically, place the wafer to be etched on the carrier 10 of the wafer carrier mechanism, turn on the RF power supply, and fix the wafer by electrostatic adsorption through the carrier 10. The gas supply device conveys process gas into the process chamber through the air inlet. The coil is powered on to ionize the process gas and generate plasma, and the active particles in the plasma react with the material on the surface of the wafer to start the etching process. During this period, helium controls the temperature of the whole wafer through the first gas flow channel 10a and the third gas flow channel respectively, and argon blows to the back of the wafer through the second gas flow channel 10b to prevent the process gas from contacting the back of the wafer and causing backside alienation. At the same time, the structural design of the edge ring 20 can avoid excessive mixing of argon and helium with the process gas above the wafer, ensuring that the etching reaction mainly occurs on the front side of the wafer. The waste gas and unreacted gas generated during the etching process are extracted through the air outlet under the action of the molecular pump. When the preset etching time or etching depth is reached, stop the power supply of the RF power supply, turn off each gas supply device, and continue to operate the molecular pump for a period of time to exhaust the residual gas in the process chamber as much as possible to complete the etching.

[0081] Each component of the etching device provided by this application works in coordination to provide a stable environment for the etching reaction. From precise wafer fixation to effective gas circulation and then to optimized overall temperature control, all contribute to maintaining the stability of various parameters during the etching process, improving the repeatability and controllability of the etching process, and being conducive to large-scale production of high-quality chips.

[0082] Optionally, the carrier 10 is provided with a first gas flow channel 10a, a second gas flow channel 10b, and a third gas flow channel; the etching device further includes: a first sensor, using an MFC, for monitoring the helium gas flow rate in the first gas flow channel 10a; a second sensor, using an MFC, for monitoring the argon gas flow rate in the second gas flow channel 10b; a third sensor, using a UPC, for monitoring the helium gas pressure in the third gas flow channel.

[0083] Among them, the MFC (mass flow controller) used by the first sensor and the second sensor is based on the thermal mass flow measurement principle. Inside the MFC, there is a heating element to heat the gas, and at the same time, there are two temperature sensors to measure the gas temperatures upstream and downstream of the heating element respectively. When the gas flows through, it will carry away heat, resulting in a change in the temperature difference between upstream and downstream. According to the relationship between the heat carried away by the gas and the gas mass flow rate, by measuring this temperature difference and combining the physical properties of the gas (such as specific heat capacity, etc.), the gas mass flow rate can be accurately calculated. For the helium gas in the first gas flow channel 10a and the argon gas in the second gas flow channel 10b, the MFC can accurately monitor their flow rates in real time for precise control of gas supply.

[0084] The UPC (general pressure controller) used by the third sensor measures the pressure by detecting the deformation of the pressure-sensitive element. In the third gas flow channel, when the helium gas generates pressure, it will cause a slight deformation of the pressure-sensitive element, and the UPC can convert this deformation into an electrical signal. After signal processing and calibration, it can accurately display the pressure value of the helium gas. By monitoring the back helium pressure, on the one hand, it can reflect the fitting situation 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.

[0085] During the etching process, helium is supplied to the first gas flow channel 10a, argon is supplied to the second gas flow channel 10b, and helium is supplied to the third gas flow channel. The first sensor (MFC) monitors the flow rate of helium in the first gas flow channel 10a in real time and feeds the flow rate data back to the control system; the second sensor (MFC) monitors the flow rate of argon in the second gas flow channel 10b in real time and feeds the flow rate data back to the control system; the third sensor (UPC) monitors the pressure of helium in the third gas flow channel in real time and feeds the pressure data back to the control system. The control system continuously receives the data fed back by the three sensors. If the flow rate of helium in the first gas flow 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 flow rate of argon in the second gas flow channel 10b is abnormal, the control system will promptly adjust the argon supply to ensure the protection effect on the back side of the wafer. For the helium pressure in the third gas flow 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 the wafer adsorption problem. After the etching is completed, the gas supply device is turned off, and each sensor continues to monitor the residual gas situation in the gas flow channel until the gas is emptied. At the same time, the sensor stores and records the data during the whole process for subsequent analysis and optimization of the etching process.

[0086] This application also provides an etching method implemented by the above etching device, including 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 supplies low-pressure helium to the third gas 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; increase the helium pressure supplied by the helium supply device to the third gas flow channel to maintain stable heat dissipation; the helium supply device supplies helium to the first gas flow channel 10a, and the two-way helium cooperates to control the temperature of the wafer; the argon supply device supplies argon to the second gas flow channel 10b; the gas supply device supplies process gas to the process chamber through the gas inlet; complete the etching; the gas supply device stops supplying process gas; the argon supply device stops supplying argon; the radio frequency power supply stops power supply; the helium supply device supplies 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 device stops supplying helium.

[0087] It is easy to understand that the RF power supply applies an adsorption voltage to the carrier 10 to facilitate the carrier 10 to fix the wafer. When the wafer is adsorbed, a relatively sealed space will be formed between the wafer and the ceramic layer of the carrier 10, and the resistance of helium gas entering this space through the third gas flow channel increases, and the flow rate will decrease accordingly. If the flow rate feedback by the third sensor is less than 1 SCCM (standard cubic centimeter per minute), it indicates that the wafer has been successfully adsorbed. After the RF power supply stops power supply, low-pressure helium gas is conveyed to the first gas flow channel 10a again. At this time, if the wafer has been desorbed, the sealed space between the wafer and the carrier 10 is damaged, and the resistance of helium gas passing through the third gas flow channel decreases, and the flow rate will increase. By monitoring the increase in the flow rate feedback by the third sensor, it can be judged that the wafer has been desorbed. By monitoring the helium gas flow rate in the third gas flow channel to judge the adsorption and desorption states of the wafer, this method is simple and accurate. It can ensure that the wafer is firmly adsorbed before etching, avoiding etching deviation caused by insufficient adsorption; and it can accurately judge desorption after etching, facilitating the subsequent blanking operation of the wafer, and improving the reliability and stability of the etching process.

[0088] Due to the excellent heat conduction performance of helium gas, blowing helium gas to the wafer through the first gas flow channel 10a and the third gas flow channel can achieve comprehensive temperature control of the wafer. The helium gas blown out from the first gas flow channel 10a mainly dissipates heat from the edge of the wafer, and the helium gas blown out from the third gas flow channel dissipates heat from the central area of the wafer. The cooperation of the two paths of helium gas can ensure that the overall temperature of the wafer is maintained in balance during the etching process. The stable temperature helps to maintain the consistency of the etching rate, improve the accuracy and uniformity of the etched pattern, and thus improve the yield of chip manufacturing.

[0089] Since the atomic mass of argon is greater than that of the 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 backside etching, and ensuring the integrity of the wafer and the accuracy of the etching process.

[0090] In a specific embodiment, the etching method includes a preparation stage, an etching stage, and an etching end stage.

[0091] Preparation stage:

[0092] Place the wafer to be etched on the carrier 10 and close the process chamber;

[0093] Turn on the RF power supply and apply a ±1500V adsorption voltage to the carrier 10 to generate an electrostatic field by the carrier 10 to adsorb the wafer;

[0094] Start the helium gas supply device and convey helium gas with a pressure of 4 Torr to the third gas flow channel. If the UPC feedback flow rate is less than 1 SCCM, it indicates that the wafer has been firmly adsorbed;

[0095] Increase the helium pressure supplied by the helium supply device to the third gas flow channel to 8 Torr.

[0096] Etching stage:

[0097] Start the helium supply device (it is possible to prepare two sets of helium supply devices to supply helium to the first gas flow channel 10a and the third gas flow channel respectively, or only set one set of helium supply device and configure valves to supply helium to the first gas flow channel 10a and / or the third gas flow channel), supply helium with a flow rate of 5 SCCM to the first gas flow channel 10a, and make the two-way helium cooperate to control the temperature of the wafer;

[0098] Start the argon supply device to supply argon to the second gas flow channel 10b to form a barrier for blocking process gas on the back of the wafer;

[0099] Start the gas supply device, and supply process gas to the process chamber through the gas inlet. The process gas diffuses, reacts, and etches the wafer in the process chamber;

[0100] During the etching stage, continuously monitor parameters such as gas flow rate and pressure in each gas flow channel to ensure that the UPC feedback flow rate is always less than 2 SCCM, and confirm that the etching environment is stable.

[0101] Etching end stage:

[0102] After reaching the preset etching time or etching depth, the gas supply device stops supplying process gas first to end the etching reaction;

[0103] Subsequently, the argon supply device stops supplying argon to end the protection of the back of the wafer;

[0104] The RF power supply stops power supply, and the carrier 10 loses its adsorption ability;

[0105] The helium supply device reduces the helium pressure supplied to the third gas flow channel to 4 Torr. At this time, the wafer will be slightly blown off the carrier 10, and the UPC feedback flow rate will increase significantly (greater than 12 SCCM), indicating that the wafer has been desorbed;

[0106] The helium supply device stops supplying helium, and the etching process ends.

[0107] In summary, the entire etching method precisely controls the supply of each gas, the adsorption and desorption of the wafer, etc., and each step is closely coordinated. This optimized process control makes the etching process more stable and controllable, helps to improve production efficiency, reduce production costs, and meet the requirements of different chip manufacturing processes.

[0108] It is easy to understand that for the helium in the first gas flow channel 10a, if the flow rate is too large, it may blow away the wafer, and if it is too small, it may lose the temperature control accuracy at the edge of the wafer, ultimately affecting the process result.

[0109] Based on a large number of tests and verifications, the UI (user interface) automatically regulates the helium gas flow rate 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:

[0110]

[0111] Specifically, when the third sensor monitors that the back-helium pressure 3 ≤ p < 5 Torr, the helium gas flow rate in the first gas flow channel 10a is adjusted to 1 SCCM.

[0112] When the third sensor monitors that the back-helium pressure 5 ≤ p < 8 Torr, the helium gas flow rate in the first gas flow channel 10a is adjusted to 3 SCCM.

[0113] When the third sensor monitors that the back-helium pressure 8 ≤ p < 10 Torr, the helium gas flow rate in the first gas flow channel 10a is adjusted to 5 SCCM.

[0114] When the third sensor monitors that the back-helium pressure 10 ≤ p < 12 Torr, the helium gas flow rate in the first gas flow channel 10a is adjusted to 8 SCCM.

[0115] When the third sensor monitors that the back-helium pressure p ≥ 12 Torr, the helium gas flow rate in the first gas flow channel 10a is adjusted to 10 SCCM.

[0116] By precisely matching the back-helium pressure with the helium gas flow rate in the first gas flow channel 10a, it is possible to avoid excessive gas flow impact caused by too large a helium gas flow rate, thereby preventing the wafer from being blown away. In this way, the wafer can be stably held on the carrier 10, providing stable basic conditions for the etching process, reducing etching deviation caused by wafer displacement, and improving the accuracy of the etched pattern and the accuracy of the lines.

[0117] At the same time, adjusting the helium gas flow rate in real time according to the back-helium pressure ensures that under different process conditions, appropriate heat transfer can be provided for the edge of the wafer. This helps to maintain the overall temperature balance of the wafer, avoid affecting the etching rate and uniformity due to abnormal edge temperature, further improve the quality and consistency of the etching process, and increase the yield rate of chip manufacturing.

[0118] This automatic regulation scheme is based on a large number of tests and verifications and can adapt to various different Recipe requirements. Regardless of the range of the 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 automatic control method not only enhances the stability of the etching process but also facilitates the management and optimization of the process, providing a strong guarantee for large-scale production of high-quality chips.

[0119] Similarly, although argon is an inert gas and does not directly participate in the etching reaction, the size of its flow rate will affect the ratio of process gases. Excessive introduction of argon will dilute the concentration of other process gases participating in the reaction, thus changing the chemical equilibrium and reaction activity 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 the process gas from contacting the back of the wafer due to its large atomic mass will be insufficient, and it cannot effectively push away the process gas on the back of the wafer, resulting in the possibility that the back of the wafer may still be etched.

[0120] 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 proportion of fluorine-based in the process gas will cause changes in the reaction activity, diffusion characteristics, etc. of the process gas. For example, fluorine-based gases usually have high reaction activity during the etching process, and different proportions of them have different requirements for argon to block the sinking of the process gas. 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.

[0121] Simply put, there is a specific relationship between the total intake volume (A) of the process gas, the total proportion (B) of the fluorine-based gas in the process gas, and the required argon flow rate (C).

[0122] Therefore, based on the total intake volume of the process gas and the total proportion of the F-based gas set by the UI according to the Recipe, the system can automatically regulate the argon flow rate in the second gas flow channel 10b according to pre-determined 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 10 mTorr):

[0123]

[0124] Specifically, when the process gas is a fluorine-based gas, when the total inlet gas volume A of the process gas is less than 100 SCCM, if the fluorine-based proportion B is less than 30%, the argon gas flow rate C in the second gas flow channel 10b = 0.4AB; when the total inlet gas volume A of the process gas is less than 100 SCCM, if the fluorine-based proportion 30% ≤ B ≤ 70%, the argon gas flow rate C in the second gas flow channel 10b = 0.5AB; when the total inlet gas volume A of the process gas is less than 100 SCCM, if the fluorine-based proportion B is greater than 70%, the argon gas flow rate C in the second gas flow channel 10b = 0.6AB.

[0125] When the total inlet gas volume 100 SCCM ≤ A ≤ 200 SCCM of the process gas, if the fluorine-based proportion B is less than 30%, the argon gas flow rate C in the second gas flow channel 10b = 0.2AB; when the total inlet gas volume 100 SCCM ≤ A ≤ 200 SCCM of the process gas, if the fluorine-based proportion 30% ≤ B ≤ 70%, the argon gas flow rate C in the second gas flow channel 10b = 0.3AB; when the total inlet gas volume 100 SCCM ≤ A ≤ 200 SCCM of the process gas, if the fluorine-based proportion B is greater than 70%, the argon gas flow rate C in the second gas flow channel 10b = 0.4AB.

[0126] When the total inlet gas volume A of the process gas is greater than 200 SCCM, if the fluorine-based proportion B is less than 30%, the argon gas flow rate C in the second gas flow channel 10b = 0.1AB; when the total inlet gas volume A of the process gas is greater than 200 SCCM, if the fluorine-based proportion 30% ≤ B ≤ 70%, the argon gas flow rate C in the second gas flow channel 10b = 0.2AB; when the total inlet gas volume A of the process gas is greater than 200 SCCM, if the fluorine-based proportion B is greater than 70%, the argon gas flow rate C in the second gas flow channel 10b = 0.3AB.

[0127] In a specific embodiment, the process gas is 50 (SCCM) CF4 + 100 (SCCM) CHF3, where the F-based proportion is 66.67% and the total gas volume is 150 SCCM; at this time, the ventilation volume of argon gas is 0.3 * 150 * 66.67% = 30 SCCM.

[0128] Precisely regulate the argon flow rate according to the total intake of process gas and the fluorine-based proportion, ensuring that the process gas maintains an appropriate ratio under various conditions. This helps to maintain the chemical balance and reaction activity of the etching reaction within the ideal range, making process parameters such as etching rate and etching depth more stable and controllable. For example, when the fluorine-based proportion is low, appropriately reduce the argon flow rate to avoid excessive dilution of the process gas and ensure that the etching reaction proceeds at an appropriate rate; when the fluorine-based proportion is high, increase the argon flow rate to prevent over-etching or uneven etching caused by the excessive activity of the fluorine-based gas. Precise control of the argon flow rate ensures that under different process conditions, there is sufficient argon to form an effective barrier layer on the back side of the wafer. When the total intake of process gas and the fluorine-based proportion change, the correspondingly adjusted argon flow rate can always effectively push away the process gas on the back side of the wafer, preventing the back side of the wafer from being etched. This is crucial for improving the quality and integrity of the wafer, helping to increase the yield rate of chip manufacturing and reduce product scrapping caused by back-side etching.

[0129] This automatic regulation scheme can adapt to a variety of different process conditions. Whether the total intake of process gas is low, moderate, or high, and regardless of the fluorine-based proportion within different ranges, it can provide appropriate argon flow rate control strategies. This enables the etching process to maintain good performance in the face of different chip manufacturing requirements, improves the adaptability of the equipment to various process recipes, enhances the versatility of the equipment, and reduces the equipment re-adjustment cost caused by process adjustment. Through automated argon flow rate regulation, the errors and uncertainties that may be brought about by manual intervention are reduced. The system can automatically adjust the argon flow rate according to real-time process parameters, ensuring that throughout the etching process, the ratio of the process gas and the protection of the back side of the wafer are always in the best state. This greatly improves the stability and reliability of the etching process, enabling each batch of chip manufacturing to obtain relatively consistent process results, which is beneficial for large-scale production of high-quality chips. Precise argon flow rate control avoids process problems caused by improper argon flow rate, such as uneven etching and back-side etching of the wafer, reducing the defective rate and the number of rework times. At the same time, the automated regulation method saves the time for manually adjusting parameters, improves the continuity and efficiency of the production process, thereby reducing production costs and increasing the production efficiency of the enterprise.

[0130] The above embodiments only represent several implementation manners of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patented application. It should be noted that for those of ordinary skill in the art, without departing from the concept of this application, several modifications and improvements can still be made, and these all belong to the protection scope of this application. Therefore, the protection scope of this application patent shall be subject to the appended claims.

Claims

1. A wafer carrier mechanism for optimizing edge processes, characterized in that, Comprising: A vehicle (10), the vehicle (10) includes a mounting portion (11) and a supporting portion (12), the supporting portion (12) is disposed on the mounting portion (11), and the supporting portion (12) is 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), there is a gap between the edge ring (20) and the supporting portion (12), and the gap serves as a gas operation channel; Wherein, the surface diameter of the supporting portion (12) for contacting the wafer is smaller than the diameter of the wafer. When the vehicle (10) supports the wafer, the edge of the wafer protrudes from the supporting portion (12) and is exposed in the gas operation channel; A first gas flow channel (10a) is provided in the vehicle (10), one end of the first gas flow channel (10a) communicates with a helium supply device, and the other end penetrates the side surface of the supporting portion (12) and communicates with the gas operation channel; The helium supply device is used to supply helium to the first gas flow channel (10a). When helium flows through the first gas flow channel (10a), the vehicle (10) can improve the temperature of the helium through heat conduction. The helium is blown towards the edge of the wafer through the first gas flow channel (10a) and the gas operation channel, and the helium can control the temperature of the edge of the wafer so as to balance the temperature of the whole wafer; A second gas flow channel (10b) is further provided in the vehicle (10), one end of the second gas flow channel (10b) communicates with an argon supply device, and the other end penetrates the top surface of the mounting portion (11) and communicates with the gas operation channel; The argon supply device is used to supply argon to the second gas flow channel (10b). The atomic mass of argon is greater than that of the process gas. After argon is blown into the gas operation channel through the second gas flow channel (10b), it can prevent the process gas from contacting the back surface of the wafer, thereby preventing the back surface of the wafer from reacting.

2. The wafer carrier mechanism for optimizing the 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 inclined surface (21), a horizontal plane and a vertical plane (22), and the horizontal plane connects the transition inclined surface (21) and the vertical plane (22); The transition inclined surface (21) extends obliquely towards 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 gas flow channel (10b) is opposite to the gap; The existence of the transition inclined surface (21) can prevent argon from flushing upwards, mixing with the process gas above the wafer and forming a laminar convection.

3. The wafer carrier mechanism for optimizing the edge process according to claim 2, wherein A gas chamber (23) is provided at the bottom of the vertical plane (22) close to the second gas flow channel (10b); During the process treatment, at least part of the argon can enter the gas chamber (23). By reducing the flow rate, the generated pressure difference can drive the argon to flow upwards along the gas operation channel.

4. The wafer carrier mechanism for optimizing the edge process according to claim 1, characterized in that, An exhaust passage (20a) is provided on the edge ring (20). One end of the exhaust passage (20a) communicates with the gas operation passage, and the other end penetrates through the outer wall of the edge ring (20). When the carrier (10) supports the wafer, the exhaust passage (20a) is adjacent to the wafer. After the argon gas blows up the back surface of the wafer, it can flow out from the side through the exhaust passage (20a), thereby preventing the argon gas from continuing to flow upward and interfering with the gas environment on the front surface of the wafer.

5. The wafer carrier mechanism for optimizing the edge process according to any one of claims 1-4, characterized in that, 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 passage is further provided in the carrier (10). One end of the third air flow passage communicates with a helium supply device, and the other end penetrates through the ceramic layer. During the process treatment, the helium gas blows toward the back surface of the wafer through the third air flow passage, 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.

6. An etching device, characterized in that, Including the wafer carrier mechanism for optimizing the edge process according to any one of claims 1-5, further comprising: A process chamber, in which the wafer carrier mechanism is provided. The process chamber can provide space for wafer etching. A radio frequency power supply, connected to the carrier (10), for supplying power to the carrier (10). After the carrier (10) is powered on, it can adsorb and fix the wafer by electrostatic adsorption. A gas supply device, connected to the air inlet of the process chamber, for supplying process gas to the process chamber. A molecular pump, connected to the air outlet of the process chamber, for pumping out the gas in the process chamber. Wherein, the air inlet is provided above the wafer carrier mechanism, and the air outlet is provided below the wafer carrier mechanism.

7. The etching device according to claim 6, characterized in that, A first air flow passage (10a), a second air flow passage (10b) and a third air flow passage are provided in the carrier (10). The etching device further comprises: A first sensor, using an MFC, for monitoring the helium gas flow rate in the first air flow passage (10a). A second sensor, using an MFC, for monitoring the argon gas flow rate in the second air flow passage (10b). A third sensor, using a UPC, for monitoring the helium gas pressure in the third air flow passage.

8. An etching method, characterized in that, Realized by the etching device according to claim 7, 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 transports low-pressure helium gas to the third air flow passage. If the flow rate feedback by the third sensor is less than 1 SCCM, it indicates that the wafer has been adsorbed. Increase the helium gas pressure transported by the helium supply device to the third air flow passage to maintain stable heat dissipation. The helium supply device transports helium gas to the first air flow passage (10a), and the two-way helium gas cooperates to control the temperature of the wafer. The argon supply device transports argon gas to the second air flow passage (10b). The gas supply device transports process gas to the process chamber through the air inlet. Complete the etching. The gas supply device stops transporting the process gas. The argon supply device stops transporting argon gas. The radio frequency power supply stops supplying power. The helium supply device transports low-pressure helium to the third gas flow channel. If the flow rate feedback by the third sensor increases, it indicates that the wafer has been desorbed; The helium supply device stops transporting helium.

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

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

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