A dry etching device

Abstract

The present invention provides a dry etching device, comprising: a vacuum chamber, a support seat, a plasma excitation unit, an etching gas generating unit and a film thickness tester; the support seat is arranged in the vacuum chamber, and is used to carry a wafer; along the height direction of the vacuum chamber, the wafer divides the vacuum chamber into an upper chamber and a lower chamber, and the support seat is located in the lower chamber; the plasma excitation unit is used to form plasma gas used for dry etching; the etching gas generating unit is used to provide etching gas used for dry etching; the film thickness tester comprises a light source and a receiver, the light source is used to emit a detection light signal to the inner wall of the upper chamber, and the receiver is used to receive a reflected light signal reflected by the inner wall of the upper chamber, and determine the thickness of the polymer on the inner wall of the upper chamber according to the change of the reflected light signal path. The present invention can improve the technical problem of low yield of wafer products caused by the polymer easily falling onto the wafer surface.

Description

Technical Field

[0001] The invention relates to the field of semiconductor equipment, and in particular to dry etching equipment. Background Art

[0002] Dry etching equipment is one of the core equipment used in semiconductor manufacturing. Its etching principle is that electron gas generates glow discharge plasma under the action of magnetic field or electric field. The etching material undergoes chemical and physical reactions under the action of plasma to form gaseous by-products. The volatile by-products desorbed from the wafer surface diffuse through the boundary layer into the convective airflow and are discharged from the process chamber under the action of the vacuum pump.

[0003] During dry etching, volatile byproducts will also generate unsaturated substances during chemical etching, and chain reactions will occur between unsaturated substances to generate polymers, which will be deposited on the surfaces of various components in the process chamber, such as the chamber wall, insulating ring, upper cover plate, and chamber bottom buffer plate. As the etching time increases, the polymer deposited on the upper cover plate and chamber wall will continue to thicken, and there is a probability that it will fall onto the surface of the wafer being etched, forming etching material residues and reducing the yield of wafer products. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a dry etching device, which can improve the technical problem of low wafer product yield caused by polymer easily falling onto the wafer surface during the etching process.

[0005] To achieve the above-mentioned purpose and other related purposes, the present invention provides a dry etching device, comprising: a vacuum chamber, a support seat, a plasma excitation unit, an etching gas generating unit and a film thickness tester; the support seat is arranged in the vacuum chamber, and is used to carry a wafer; along the height direction of the vacuum chamber, the wafer divides the vacuum chamber into an upper part and a lower part of the chamber, and the support seat is located in the lower part of the chamber; the plasma excitation unit is used to form plasma gas used for dry etching; the etching gas generating unit is used to provide etching gas used for dry etching; the film thickness tester comprises a light source and a receiver, the light source is used to emit a detection light signal to the inner wall of the upper part of the chamber, and the receiver is used to receive a reflected light signal reflected by the inner wall of the upper part of the chamber, and determine the thickness of the polymer on the inner wall of the upper part of the chamber according to the change of the reflected light signal path.

[0006] In an example of the dry etching equipment of the present invention, the vacuum chamber includes a surrounding side wall, a top wall and a bottom wall, and the top wall and the bottom wall are respectively arranged at both ends of the side wall in the height direction; the support seat is arranged on the bottom wall, and the detection light signal is irradiated to the side wall above the support seat and then reflected to the receiver.

[0007] In an example of the dry etching device of the present invention, the material of the side wall is aluminum.

[0008] In an example of the dry etching device of the present invention, the position where the detection light irradiates the side wall is set as the detection point, and along the height direction of the vacuum chamber, the distance between the detection point and the upper surface of the wafer is smaller than the distance between the detection point and the top wall.

[0009] In an example of the dry etching device of the present invention, the support base includes an electrostatic chuck for mounting a wafer and an insulating ring arranged on the periphery of the electrostatic chuck, and the receiver is fixedly mounted on the insulating ring.

[0010] In an example of the dry etching device of the present invention, the receiver is embedded in the insulating ring.

[0011] In an example of the dry etching device of the present invention, the insulating ring is made of ceramic material or quartz material.

[0012] In an example of the dry etching device of the present invention, the wall of the vacuum cavity is provided with a light-transmitting area for the detection light signal to penetrate, the light source is arranged outside the vacuum cavity, and the light outlet of the light source faces the light-transmitting area.

[0013] In an example of the dry etching device of the present invention, the vacuum chamber is provided with an opening, the opening is located above the support seat, an upper cover plate is sealed and connected to the opening, the upper cover plate is made of a light-transmitting material, and the light source is installed on the upper cover plate.

[0014] In an example of the dry etching device of the present invention, a protective cover is arranged outside the vacuum chamber, a receiving cavity for containing a cooling medium is formed between the protective cover and the outer wall of the vacuum chamber, and a light source is installed in the receiving cavity.

[0015] The dry etching equipment in the present invention can, by setting a film thickness tester, on the one hand, realize real-time monitoring of the thickness of the polymer attached to the upper inner wall of the cavity during the etching process, so that the operator can timely discover the abnormal thickness of the polymer in the vacuum cavity so as to intervene in time, thereby reducing the probability of residual etching material on the wafer surface caused by polymer shedding during the etching process, thereby improving the product yield of the wafer. On the other hand, during the vacuum cavity cleaning process, the residual thickness of the polymer on the inner wall of the vacuum cavity can be monitored in real time by the film thickness tester to determine whether the vacuum cavity is cleaned, which can ensure the cleaning effect of the vacuum cavity and avoid the waste of production time caused by excessive cleaning, thereby correspondingly improving the normal use time of the interference etching equipment to ensure the etching production efficiency of the wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0017] Figure 1 It is a cross-sectional structural schematic diagram of an embodiment of a dry etching device of the present invention;

[0018] Figure 2 for Figure 1 A local enlarged view of area A;

[0019] Figure 3 It is a schematic diagram of the transmission path when the detection light emitted by the light source irradiates the polymer with a thickness of d1;

[0020] Figure 4 Schematic diagram of the transmission path of the detection light emitted by the light source when it irradiates the polymer with a thickness of d2.

[0021] Component number description

[0022] 10. Dry etching equipment; 11. Vacuum chamber; 101. Upper part of the chamber; 102. Lower part of the chamber; 111. Side wall; 112. Bottom wall; 113. Top wall; 114. Upper cover; 115. Opening; 120. Support seat; 121. Electrostatic suction cup; 1211. Wafer support surface; 122. Insulating ring; 1221. Groove; 123. Fixing part; 124. Focusing ring; 1241. Positioning part; 1242. Mounting part; 130. Plasma excitation unit; 140. Etching gas generating unit; 141. Gas transmission device; 142. Guide device; 150. Film thickness tester; 151. Light source; 152. Receiver; 160. Protective cover; 170. Accommodating chamber; 180. Host controller; 20. Wafer; 30. Polymer. DETAILED DESCRIPTION

[0023] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0024] It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner. Therefore, the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0025] In the present invention, it should be noted that, if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, if the terms "first" and "second" appear, they are only used for description and distinction purposes, and cannot be understood as indicating or implying relative importance.

[0026] The inventors have found through research on existing etching processes that mainstream equipment manufacturers on the market use two main methods to solve the problem of polymer shedding that easily occurs during dry etching, resulting in reduced etching product yield on wafers.

[0027] One method is to perform a waferless dry etching automatic cleaning before and after etching each wafer. Although this action can improve the above problems to a certain extent, it will also waste a lot of time, resulting in low production efficiency of the equipment. At the same time, there is no means to monitor whether it is clean or over-cleaned after automatic cleaning, so there is also a probability of polymer falling off during the etching process.

[0028] Another method is to coat the chamber wall with a protective film of a certain thickness through plasma reaction before the wafer process. This allows each wafer etching to be performed in the same environment. At the same time, during the etching process, this protective layer can also protect the side wall from being eroded by plasma. However, the thickness of the protective film of this solution cannot be monitored in real time, and the polymer accumulated on the chamber wall may also fall off, causing the etching material to remain on the wafer surface, reducing the yield of the wafer product. In view of this, the inventor proposed a dry etching device.

[0029] See also Figures 1 to 4 The dry etching device 10 provided by the present invention can monitor the thickness of the polymer 30 on the inner wall of the vacuum chamber 11 in real time during the etching process by setting a film thickness tester 150, so as to timely detect the abnormal thickness of the polymer 30 and facilitate timely intervention, thereby improving the problem of reduced product yield of the wafer 20 caused by the polymer 30 falling off the wall.

[0030] See also Figure 1 and Figure 2 The dry etching device 10 of the present invention includes: a vacuum chamber 11, a support seat 120, a plasma excitation unit 130, an etching gas generating unit 140 and a film thickness tester 150.

[0031] The shape of the vacuum chamber 11 can be various, such as a rectangular parallelepiped, a cylinder, etc., whichever is more suitable for accommodating the wafer 20 to be etched. In the present embodiment, the vacuum chamber 11 is a cavity structure that is approximately cylindrical. The vacuum chamber 11 can be an integral cavity structure, or a cavity structure formed by splicing a plurality of plates. It should be noted that, in theory, the material of the vacuum chamber 11 can be any material that meets the requirements of the dry etching process conditions, but considering that during the etching process, the vacuum chamber 11 requires effective thermal management to maintain a constant temperature, therefore, in actual applications, the vacuum chamber 11 usually uses a metal material with good thermal conductivity, such as stainless steel, aluminum or other special alloys.

[0032] The support seat 120 is disposed in the vacuum chamber 11 and is used to support the wafer 20. The support seat 120 can be fixedly connected to the vacuum chamber 11, or can be directly placed on the bottom wall 112 of the vacuum chamber 11, as long as the support seat 120 can be kept fixed relative to the vacuum chamber 11 during the etching process. The wafer 20 can be fixed to the support seat 120 by various methods such as electrostatic adsorption, magnetic adsorption, vacuum adsorption, etc., which are not limited in this embodiment. Along the height direction of the vacuum chamber 11 (such as Figure 1 As shown in the Z axis, the wafer 20 divides the vacuum chamber 11 into an upper chamber 101 and a lower chamber 102 , and the support seat 120 is located in the lower chamber 102 .

[0033] The etching gas generating unit 140 includes a gas transmission device 141 and a flow guiding device 142. The gas transmission device 141 is used to provide etching gas for dry etching. The flow guiding device 142 is arranged at the gas outlet of the gas transmission device 141 to guide the etching gas. In the present embodiment, the flow guiding device 142 is a gas dispersion disk arranged inside the vacuum chamber 11. The plasma excitation unit 130 is used to form plasma gas for dry etching. Specifically, the plasma laser unit may include a radio frequency power supply, a coupling coil, an electrode system, etc. After the etching gas is input into the vacuum chamber 11 through the gas transmission device 141 and the flow guiding device 142, the radio frequency power supply applies a high-frequency electric field through the coupling coil or the electrode system, so that the etching gas molecules absorb energy and ionize to form plasma. The ions and neutral active particles in the plasma react physically and chemically with the surface of the material to be etched, resulting in the removal of the material, thereby realizing the etching of the wafer 20. Most of the by-products (usually volatile chemicals) generated during the etching process will be extracted by the vacuum system, and a small part will generate unsaturated substances during the chemical etching process. Chain reactions will occur between the unsaturated substances to generate polymers 30 that are not easily volatile. These polymers 30 will be adsorbed on the exposed surfaces of various components in the vacuum chamber 11, such as the inner wall of the vacuum chamber 11, the outer wall of the support seat 120, etc.

[0034] As the etching time increases, the thickness of the polymer 30 adsorbed on the wall of the vacuum chamber 11 will gradually increase. When the thickness reaches a certain level, there will be a risk of falling off, which will further contaminate the surface of the wafer 20 and affect the product yield of the wafer 20. In particular, the inner wall position of the upper part 101 of the chamber above the wafer 20 has the highest probability of the polymer 30 falling onto the surface of the wafer 20 when it falls off.

[0035] See also Figure 1 and Figure 2The film thickness tester 150 includes a light source 151 and a receiver 152. The light source 151 is used to emit a detection light signal to the inner wall of the upper part 101 of the cavity. The receiver 152 is used to receive the reflected light signal reflected by the inner wall of the upper part 101 of the cavity, and determine the thickness of the polymer 30 on the inner wall of the upper part 101 of the cavity according to the change of the reflected light signal path. The receiver 152 is installed inside the vacuum cavity 11. The light source 151 can be installed inside the vacuum cavity 11 or outside the vacuum cavity 11, as long as the receiver 152 can receive the reflected light signal reflected by the inner wall of the upper part 101 of the cavity. The specific position where the light source 151 emits the detection light signal to the inner wall of the upper part 101 of the cavity is not limited, and can be a position close to the surface of the wafer 20 or a position far from the surface of the wafer 20. One film thickness tester 150 can be set in the vacuum cavity 11, or multiple film thickness testers 150 can be set. Optionally, in this embodiment, considering the equipment cost and installation cost, a film thickness detector is provided in the vacuum chamber 11. It should be noted that the polymer 30 in this embodiment is a translucent material that can be penetrated by the detection light.

[0036] Please refer to 1 to Figure 3 , when the thickness of the polymer 30 attached to the inner wall of the upper part 101 of the cavity is d1, when the detection light signal emitted by the light source 151 irradiates the inner wall of the upper part 101 of the cavity, the detection light signal will enter the polymer 30 from point A, penetrate the polymer 30 along the AB path, and reach the position of point B on the inner wall of the upper part 101 of the cavity, after being reflected by the inner wall of the upper part 101 of the cavity, it will penetrate the polymer 30 in the reverse direction along the path BC, and finally reach the receiving point position D on the receiver 152. Under the condition that the light output angle and light output wavelength of the light source 151 remain unchanged, as the thickness of the polymer 30 changes, that is, when the thickness of the polymer 30 increases from d1 to d2, as Figure 4 As shown, the transmission path of the detection light between the polymer and the inner wall of the upper part 101 of the cavity will also change accordingly. The transmission path of the detection light changes from the original ABCD to the new transmission path A'B'C'D'. Figure 3 and Figure 4 It can be clearly seen that the positions of point D and point D' on the receiver 152 have changed. Therefore, by quantitatively analyzing the offset changes of the receiving point positions on the receiver 152, the thickness of the polymer 30 corresponding to different paths can be derived, thereby realizing the detection of the thickness of the polymer 30 attached to the inner wall of the upper part 101 of the cavity.

[0037] By setting up the film thickness tester 150, the present embodiment can realize real-time monitoring of the thickness of the polymer 30 attached to the inner wall of the upper part 101 of the cavity during the etching process, so that the operator can timely discover the abnormal thickness of the polymer 30 in the vacuum cavity 11, so as to intervene in time, thereby reducing the probability of the etched material residue on the surface of the wafer 20 caused by the falling off of the polymer 30 during the etching process, thereby improving the product yield of the wafer 20. Compared with the method of performing automatic cleaning without dry etching of the wafer 20 before and after etching each wafer 20 in the prior art, the method in the present embodiment only needs to clean when it is detected that the thickness of the polymer 30 reaches the set limit, so it can save cleaning time and improve the production efficiency of the equipment. On the other hand, during the cleaning process of the vacuum chamber 11, the residual thickness of the polymer 30 on the inner wall of the vacuum chamber 11 can be monitored in real time by the film thickness tester 150 to determine whether the vacuum chamber 11 is cleaned. This can not only ensure the cleaning effect of the vacuum chamber 11, but also avoid the waste of production time due to excessive cleaning, thereby correspondingly improving the normal use time of the interference etching equipment to ensure the etching production efficiency of the wafer 20.

[0038] See also Figure 1 In this embodiment, the dry etching device 10 further includes a host controller 180 disposed outside the vacuum chamber 11, and the host controller 180 is used to control the etching process of the wafer 20. The receiver 152 can be connected to the host controller 180 by electrical signals via a wireless sensor, so as to transmit the film thickness monitoring data to the host controller 180 for the operator to view.

[0039] See also Figure 1In an example of the dry etching device 10 of the present invention, the vacuum chamber 11 includes a surrounding side wall 111, a top wall 113 and a bottom wall 112, and the top wall 113 and the bottom wall 112 are respectively arranged at both ends of the height direction of the side wall 111. The support seat 120 is arranged on the bottom wall 112, and the detection light signal is irradiated to the side wall 111 located above the support seat 120 and then reflected to the receiver 152. It should be noted that the side wall 111 located above the support seat 120 in this embodiment refers to the side wall of the upper part 101 of the chamber. Although, inside the vacuum chamber 11, the polymer 30 can be attached to the wall at any position of the vacuum chamber 11, since the surface of the wafer 20 is the most active area for chemical reactions, this position is the position where the active particles (such as ions, free radicals) in the plasma directly contact and react with the material. Therefore, the position of the wall of the vacuum chamber 11 closer to the surface of the wafer 20 is the area where the polymer 30 is adsorbed more, and correspondingly, the polymer 30 at this position also reaches the thickness limit first, and is the position where it first falls off. In this embodiment, since the detection light signal is irradiated to the side wall 111 located above the support seat 120 and then reflected to the receiver 152, it is possible to detect the thickness of the polymer 30 at the position of the side wall 111 located above the support seat 120. This position is closer to the surface of the wafer 20 than the top wall 113, so the thickness of the polymer 30 at this position can better prevent the polymer 30 from falling off from the wall of the vacuum chamber 11.

[0040] See also Figure 1 Although the material of the vacuum chamber 11 can be a variety of metal materials that meet the heat dissipation conditions and use requirements, optionally, in an example of the dry etching device 10 of the present invention, the material of the side wall 111 is aluminum. Aluminum has good thermal conductivity, which helps to quickly transfer and disperse heat during the etching process and maintain the uniformity of the temperature inside the vacuum chamber 11; at the same time, since a dense oxide film is usually formed on the surface of the aluminum, it has good corrosion resistance. Moreover, the surface of the aluminum is relatively smooth, which is convenient for cleaning the polymer 30 attached to the surface. Further, in one embodiment, the surface of the aluminum facing the vacuum chamber 11 can also be anodized to further improve the corrosion resistance and wear resistance of the aluminum surface, thereby improving the service life of the side wall 111. In another embodiment, the surface of the aluminum facing the vacuum chamber 11 can also be coated with a corrosion-resistant layer with insulating properties, which can improve the corrosion resistance and insulation properties of the aluminum surface, thereby improving the service life of the side wall 111.

[0041] See also Figure 1 In an example of the dry etching device 10 of the present invention, the position where the detection light irradiates the side wall 111 is set as the detection point (such as Figure 1(As shown in point E in the figure), along the height direction of the vacuum chamber 11, the distance between the detection point and the upper surface of the wafer 20 is H1, and the distance between the detection point and the top wall 113 is H2, and H1 is smaller than H2. The specific numerical values ​​of H1 and H2 are not limited, as long as H1 is smaller than H2. With this arrangement, the position of the detection point can be closer to the surface of the wafer 20, and the thickness of the polymer 30 can be detected at this position, so as to better prevent the probability of the polymer 30 falling off the wall of the vacuum chamber 11. It should be noted that point E is the position where the detection light irradiates the side wall 111 when the polymer 30 is not attached to the side wall 111.

[0042] See also Figure 1 and Figure 2 In an example of the dry etching device 10 of the present invention, the support seat 120 includes an electrostatic chuck 121 for mounting the wafer 20 and an insulating ring 122 arranged on the periphery of the electrostatic chuck 121, and the receiver 152 is fixedly mounted on the insulating ring 122. The electrostatic chuck 121 has a wafer supporting surface 1211, and the wafer 20 is electrostatically adsorbed on the wafer supporting surface 1211. On the premise of meeting the support requirements of the wafer supporting surface 1211 for the wafer 20, the shape of the wafer supporting surface 1211 can be a variety of shapes such as circular, square or polygonal. Optionally, in this embodiment, the wafer supporting surface 1211 is a circular surface shape coaxially arranged with the wafer 20. Correspondingly, the electrostatic chuck 121 is a cylindrical structure. The support seat 120 also includes a fixing portion 123, one end of which is fixedly connected to the bottom wall 112, and the other end is fixedly connected to the end of the electrostatic chuck 121 where the wafer supporting surface 1211 is not arranged. The insulating ring 122 is sleeved on the outer periphery of the electrostatic suction cup 121 and fixedly connected to the outer peripheral wall of the electrostatic suction cup 121. The fixed connection method can be a shaft hole matching connection, an adhesive connection, or a bump groove snap connection and other methods. The material of the insulating ring 122 can be a corrosion-resistant and high-temperature resistant insulating material such as ceramic material, insulating resin or insulating rubber. The receiver 152 can be fixedly connected to the insulating ring 122 by bolts, or it can be fixed to the insulating ring 122 by snap connection and other connection methods. The setting position of the receiver 152 on the insulating ring 122 is not specifically limited in this embodiment, as long as the receiver 152 can accurately receive the detection light signal reflected by the side wall 111. By installing the receiver 152 on the insulating ring 122, the receiver 152 can be located below the wafer 20, thereby reducing the impact on the detection light signal receiving ability caused by the adsorption of the polymer 30 on the receiver 152. At the same time, since this position is closer to the detection point on the side wall 111, the reflected signal of the detection light received by the receiver 152 is stronger, which is beneficial to improving the detection accuracy of the film thickness detector.

[0043] Please note that Figure 1 and Figure 2A focusing ring 124 is also provided on the periphery of the wafer 20. The focusing ring 124 is fixed to the periphery of the electrostatic chuck 121. The focusing ring 124 includes a positioning portion 1241 and a mounting portion 1242 that are connected to each other. The positioning portion 1241 surrounds the periphery of the wafer 20. Along the radial direction of the wafer 20, one end of the positioning portion 1241 corresponds to and matches the outer peripheral surface of the wafer 20; the other end of the positioning portion 1241 is connected to one end of the mounting portion 1242. The mounting portion 1242 surrounds the periphery of the electrostatic chuck 121 and is fixedly connected to the outer peripheral surface of the electrostatic chuck 121. Along the axial direction of the wafer 20, one end of the mounting portion 1242 that is away from the positioning portion 1241 abuts against the upper end surface of the insulating ring 122 located below. By providing the focusing ring 124, it is helpful to achieve more uniform etching on the entire surface of the wafer 20 and reduce the etching difference caused by uneven plasma density. The uniformity of etching on the surface of the wafer 20 can be improved.

[0044] See also Figure 1 and Figure 2 In an example of the dry etching device 10 of the present invention, the receiver 152 is embedded in the insulating ring 122. Specifically, the insulating ring 122 is provided with a groove 1221, the shape of the groove 1221 is adapted to the shape of the body of the receiver 152, and the body of the receiver 152 is embedded in the groove 1221, so that the receiver 152 is clamped in the groove 1221, and the receiver 152 is fixedly installed on the insulating ring 122. The receiving end of the receiver 152 is exposed in the vacuum chamber 11 to receive the detection light signal. In this way, the receiver 152 can be stably and reliably installed in the vacuum chamber 11, and no additional components will be introduced in the vacuum chamber 11, which is more conducive to ensuring the stability of the etching process environment.

[0045] See also Figure 1 and Figure 2 In an example of the dry etching device 10 of the present invention, the insulating ring 122 is made of ceramic material. Compared with other insulating materials, ceramic material has high temperature resistance and can withstand the high temperature generated during dry etching; at the same time, the chemical properties of ceramic material are relatively stable, not only has high corrosion resistance, but also is not easy to react with the chemical substances in the etching process, so it helps to maintain the stability of the operation of the equipment. In addition, the groove 1221 set on the insulating ring 122 of ceramic material is not easy to deform during use, and can maintain a relatively stable fixed relationship with the body of the receiver 152, so that the probability of displacement of the receiver 152 during use can be reduced, and then the film thickness tester 150 can ensure the detection accuracy of the thickness of the polymer 30. In another embodiment, the insulating ring 122 can also be made of quartz material, which also has better high temperature resistance and relatively stable chemical properties, so the above-mentioned beneficial effects can also be achieved.

[0046] In an example of the dry etching device 10 of the present invention, the wall of the vacuum cavity 11 is provided with a light-transmitting area for the detection light signal to penetrate, and the light-transmitting area can be located at any position such as the top wall 113 and the side wall 111. The light-transmitting area can be a local opening on the top wall 113 or the side wall 111, and the local opening position is blocked with a light-transmitting material to form a light-transmitting area; or the top wall 113 can be made of a light-transmitting material as a whole, or any side of the side wall 111 can be made of a light-transmitting material. The light source 151 is arranged outside the vacuum cavity 11, and the light outlet of the light source 151 is directly opposite to the light-transmitting area. The detection light emitted from the light outlet of the light source 151 will pass through the light-transmitting area and enter the inside of the vacuum cavity 11. In this way, the light source 151 can be installed outside the vacuum cavity 11, so as to avoid the probability that the light outlet adsorbs the polymer 30 and affects the light-emitting effect when the light source 151 is located inside the vacuum chamber, thereby further improving the detection accuracy of the film thickness tester 150.

[0047] In order to facilitate the placement of the wafer 20 from the vacuum chamber 11, please refer to Figure 1 and Figure 2 In an example of the dry etching device 10 of the present invention, the vacuum chamber 11 is provided with an opening 115, and the opening 115 is located above the support seat 120. The size and shape of the opening 115 are adapted to the diameter of the wafer 20 to ensure that the wafer 20 can be smoothly taken out from the opening 115. The opening 115 is sealed with an upper cover plate 114, and the upper cover plate 114 can be connected to the opening 115 by snap-fit ​​sealing, or can be connected to the opening 115 by thread sealing, etc. The upper cover plate 114 is made of a light-transmitting material, and the light source 151 is installed on the upper cover plate 114. The specific installation position of the light source 151 on the upper cover plate 114 is not limited, and is subject to the light-emitting angle requirement of the light source 151. The light-transmitting material can be quartz, transparent ceramics or transparent plastic, etc. Preferably, in this embodiment, the upper cover plate 114 is made of quartz material with good light transmittance. In this embodiment, since the entire upper cover 114 is made of a light-transmitting material, the installation position of the light source 151 on the upper cover 114 can be selected in a wider range, so that it can more conveniently correspond to the installation position of the receiver 152 installed on the insulating ring 122, and can better solve the problem of limited installation position of the receiver 152 on the insulating ring 122.

[0048] See also Figure 1 and Figure 2In an example of the dry etching device 10 of the present invention, a protective cover 160 is provided on the outside of the vacuum chamber 11, and a receiving chamber 170 for containing a cooling medium is formed between the protective cover 160 and the outer wall of the vacuum chamber 11. The cooling medium in the receiving chamber 170 can be a cooling liquid or a cooling gas, etc., as long as it can exchange heat with the wall of the vacuum chamber 11 to adjust the temperature inside the vacuum chamber 11. By arranging the cooling medium in the receiving chamber 170, the temperature in the vacuum chamber 11 can be controlled and maintained, ensuring the normal operation and use of the dry etching device 10. The light source 151 is installed in the receiving chamber 170, that is, the light source 151 is surrounded by the cooling medium. In this way, while the cooling medium adjusts the temperature of the vacuum chamber 11, it can also adjust the working temperature of the light source 151, so that the normal operation and use of the light source 151 can also be ensured. Specifically, the light source 151 can be installed on the protective cover 160 or on the outer wall of the vacuum chamber 11, as long as the installation position of the light source 151 in the accommodating chamber 170 is stable and reliable. It should be noted that the cooling medium in this embodiment can not only cool down the vacuum chamber 11 when the temperature of the vacuum chamber 11 is too high, but also transfer heat to the vacuum chamber 11 to increase the temperature when the temperature of the vacuum chamber 11 is too low, thereby realizing a two-way regulation of the temperature increase and decrease in the vacuum chamber 11, and maintaining the stability of the internal working temperature of the vacuum chamber 11.

[0049] The dry etching equipment in the present invention can realize real-time monitoring of the thickness of the polymer attached to the upper inner wall of the cavity during the etching process by setting a film thickness tester, so that the operator can timely discover the abnormal thickness of the polymer in the vacuum cavity so as to intervene in time, thereby reducing the probability of residual etching material on the wafer surface caused by polymer shedding during the etching process, thereby improving the product yield of the wafer. On the other hand, during the vacuum cavity cleaning process, the residual thickness of the polymer on the inner wall of the vacuum cavity can be monitored in real time by the film thickness tester to determine whether the vacuum cavity is cleaned, which can ensure the cleaning effect of the vacuum cavity and avoid the waste of production time caused by excessive cleaning, thereby correspondingly improving the normal use time of the interference etching equipment to ensure the etching production efficiency of the wafer. Therefore, the present invention effectively overcomes some practical problems in the prior art and has a high utilization value and use significance. The above embodiments only illustrate the principles and effects of the present invention, and are not used to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those having ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A dry etching device, characterized in that: include: Vacuum chamber; A support seat, disposed in the vacuum chamber, for supporting the wafer; Along the height direction of the vacuum chamber, the wafer divides the vacuum chamber into an upper portion and a lower portion of the chamber, and the support seat is located at the lower portion of the chamber; A plasma excitation unit, used to form plasma gas used for dry etching; An etching gas generating unit, used for providing etching gas used for dry etching; A film thickness tester, the film thickness tester comprising a light source and a receiver, the light source being used to emit a detection light signal to the inner wall of the upper part of the cavity, the receiver being used to receive a reflected light signal reflected by the inner wall of the upper part of the cavity, and determining the thickness of the polymer on the inner wall of the upper part of the cavity according to the change in the path of the reflected light signal; the vacuum cavity comprising a surrounding side wall, a top wall and a bottom wall, the top wall and the bottom wall being respectively arranged at both ends of the height direction of the side wall; the support seat being arranged on the bottom wall, the detection light signal being irradiated to the side wall above the support seat and then reflected to the receiver; the position where the detection light is irradiated to the side wall is set as a detection point, and along the height direction of the vacuum cavity, the distance between the detection point and the upper surface of the wafer is smaller than the distance between the detection point and the top wall.

2. The dry etching equipment according to claim 1, characterized in that: The side wall is made of aluminum.

3. The dry etching equipment according to claim 1, characterized in that: The support seat comprises an electrostatic chuck for mounting a wafer and an insulating ring arranged on the periphery of the electrostatic chuck, and the receiver is fixedly mounted on the insulating ring.

4. The dry etching equipment according to claim 3, characterized in that: The receiver is embedded in the insulating ring.

5. The dry etching equipment according to claim 4, characterized in that: The insulating ring is made of ceramic or quartz material.

6. The dry etching equipment according to any one of claims 1 to 5, characterized in that: The wall of the vacuum cavity is provided with a light-transmitting area for the detection light signal to penetrate, the light source is arranged outside the vacuum cavity, and the light outlet of the light source faces the light-transmitting area.

7. The dry etching equipment according to claim 6, characterized in that: The vacuum chamber is provided with an opening, and the opening is located above the support seat. An upper cover plate is sealed and connected to the opening. The upper cover plate is made of a light-transmitting material, and the light source is installed on the upper cover plate.

8. The dry etching equipment according to claim 7, characterized in that: A protective cover is arranged on the outside of the vacuum cavity, a receiving cavity for containing a cooling medium is formed between the protective cover and the outer wall of the vacuum cavity, and the light source is installed in the receiving cavity.

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