Patent Publication Number: US-2021183629-A1

Title: Ring assembly, substrate support assembly and substrate processing apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of Japanese Patent Application No. 2019-225271 filed on Dec. 13, 2019, the entire disclosures of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to a ring assembly, a substrate support assembly, and a substrate processing apparatus. 
     BACKGROUND ART 
     JP-A-2018-129386 discloses a plasma processing apparatus including a processing chamber and a substrate support which is provided in the processing chamber and on which a target object is disposed. The plasma processing apparatus described in JP-A-2018-129386 has an edge ring provided on the substrate support so as to surround the target object and an annular member disposed so as to surround the outer peripheral surface of the edge ring. JP-A-2014-090177 discloses a process kit which is mounted near a workpiece in a semiconductor manufacturing process plasma chamber. The process kit described in JP-A-2014-090177 is made of a dielectric material, has a dielectric shield which has a central opening portion and of which outer edge is outside the outer edge of the workpiece, and has a conductive collar which has a central opening portion and of which outer edge is outside the outer edge of the workpiece. The conductive collar described in JP-A-2014-090177 overlies on at least a portion of the dielectric shield. 
     SUMMARY 
     According to one aspect of the disclosure, there is provided a ring assembly including a conductive edge ring, an insulating annular member including at least an inner peripheral portion disposed on the edge ring, and a conductive member disposed on at least a portion of an upper surface of the annular member overlapping with the edge ring in top plan view. 
     The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a cross-sectional view illustrating a schematic configuration of a substrate processing apparatus according to an embodiment. 
         FIG. 2  is a cross-sectional view illustrating a ring assembly according to the embodiment. 
         FIG. 3  is a cross-sectional view of Modified Example of the ring assembly according to the embodiment. 
         FIG. 4  is a cross-sectional view of Modified Example of the ring assembly according to the embodiment. 
         FIG. 5  is a cross-sectional view of a ring assembly according to Comparative Example. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     In the following detailed description, reference is made to the accompanying drawings, which form a part thereof. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made without departing from the spirit or scope of the subject matter presented here. 
     Hereinafter, embodiments for carrying out the disclosure will be described with reference to the drawings. In addition, in this specification and the drawings, substantially the same configurations will be denoted by the same or corresponding reference numerals to omit redundant description. 
     &lt;Substrate Processing Apparatus&gt; 
     First, an example of an overall configuration of a substrate processing apparatus  1  will be described with reference to  FIG. 1 .  FIG. 1  is a cross-sectional view illustrating a schematic configuration of the substrate processing apparatus  1  according to the embodiment. In addition, in the embodiment, an example where the substrate processing apparatus  1  is a reactive ion etching (RIE) type substrate processing apparatus will be described. However, the substrate processing apparatus  1  may be, for example, a plasma etching apparatus or a plasma chemical vapor deposition (CVD) apparatus. 
     In  FIG. 1 , the substrate processing apparatus  1  has a grounded cylindrical processing chamber  2  made of metal, for example, aluminum or stainless steel. A disc-shaped substrate support  10  on which a substrate W is supported is provided inside the processing chamber  2 . The substrate support  10  includes a base  11  and an electrostatic chuck  25 . The base  11  functions as a lower electrode. The base  11  is made of, for example, aluminum. The base  11  is supported by a cylindrical support portion  13  extending vertically upward from the bottom of the processing chamber  2  via an insulating cylindrical holding member  12 . 
     An exhaust passage  14  is formed between the side wall of the processing chamber  2  and the cylindrical support portion  13 . An annular baffle plate  15  is arranged at the inlet or midway of the exhaust passage  14 , and an exhaust port  16  is provided at the bottom. An exhaust device  18  is connected to the exhaust port  16  via an exhaust pipe  17 . Herein, the exhaust device  18  has a dry pump and a vacuum pump and decompresses a processing space in the processing chamber  2  to a predetermined degree of vacuum. In addition, a gate valve  20  is attached to the side wall of the processing chamber  2  to open and close a loading/unloading port  19  for the substrate W. 
     A first radio frequency power supply  21   a  is connected to the base  11  via a first matching unit  22   a . In addition, a second radio frequency power supply  21   b  is connected to the base  11  via a second matching unit  22   b . The first radio frequency power supply  21   a  supplies a radio frequency power for plasma generation having a predetermined frequency (for example, 100 MHz) to the base  11 . The second radio frequency power supply  21   b  supplies a radio frequency power for ion attraction having a predetermined frequency (for example, 13 MHz) lower than that of the first radio frequency power supply  21   a  to the base  11 . 
     A shower head  24  which also functions as an upper electrode is provided on the ceiling of the processing chamber  2 . Accordingly, radio frequency voltages of two frequencies from the first radio frequency power supply  21   a  and the second radio frequency power supply  21   b  are applied between the base  11  and the shower head  24 . 
     The electrostatic chuck  25  that attracts the substrate W by an electrostatic force is provided on the upper surface of the base  11 . The electrostatic chuck  25  is configured by interposing an electrode plate  26  made of a conductive film between a pair of dielectric films. A DC power supply  27  is electrically connected to the electrode plate  26 . The DC power supply  27  applies a DC voltage to the electrode plate  26  under the control of a controller  43  (to be described later). The electrostatic chuck  25  generates an electrostatic force such as a Coulomb force by the voltage applied to the electrode plate  26  from the DC power supply  27  and attracts and holds the substrate W to the electrostatic chuck  25  by the electrostatic force. 
     A flow channel  31  is provided in the base  11 . A heat exchange medium (for example, a coolant) is supplied from a chiller unit  32  to the flow channel  31  via pipes  33  and  34 , and the processing temperature of the substrate W on the electrostatic chuck  25  is controlled by the temperature of the heat exchange medium. 
     In addition, a heat transfer gas supply unit  35  is connected to the electrostatic chuck  25  via a gas supply line  36 . The heat transfer gas supply unit  35  supplies the heat transfer gas to a space interposed between the electrostatic chuck  25  and the substrate W via the gas supply line  36 . Examples of the heat transfer gas include a gas having thermal conductivity, for example, He gas. 
     The shower head  24  on the ceiling has an electrode plate  37  on the lower surface having a plurality of gas injection holes  37   a  and an electrode support  38  that detachably supports the electrode plate  37 . A diffusion space  39  is provided inside the electrode support  38 , and a processing gas supply unit  40  is connected to a gas inlet  38   a  communicating with the diffusion space  39  via a gas supply pipe  41 . 
     Each component of the substrate processing apparatus  1  is connected to the controller  43 . For example, the exhaust device  18 , the first radio frequency power supply  21   a , the second radio frequency power supply  21   b , the DC power supply  27 , the chiller unit  32 , the heat transfer gas supply unit  35 , and the processing gas supply unit  40  are connected to the controller  43 . The controller  43  controls each component of the substrate processing apparatus  1 . 
     The controller  43  includes a central processing unit (CPU) (not illustrated) and a storage device such as a memory and allows the substrate processing apparatus  1  to execute each processing by reading a program and a processing recipe stored in the storage device. 
     In the substrate processing apparatus  1 , an insulating annular member  80  is provided outside an edge ring  30 . In addition, a conductive member  81  is provided on the upper surface of the insulating annular member  80 . In some cases, a combination of the edge ring  30 , the insulating annular member  80 , and the conductive member  81  may be referred to as a ring assembly  5 . In addition, the details of the ring assembly  5  will be described later. A combination of the ring assembly  5  and the substrate support  10  may be referred to as a substrate support assembly  6  in some cases. 
     In the substrate processing apparatus  1 , during the dry etching process, first, the gate valve  20  is set to the opened state, so that the substrate W to be processed is loaded into the processing chamber  2  and supported on the electrostatic chuck  25 . Then, in the substrate processing apparatus  1 , a processing gas (for example, a mixed gas containing C 4 F 8  gas, O 2  gas, and Ar gas) is introduced into the processing chamber  2  from the processing gas supply unit  40  at a predetermined flow rate and a predetermined flow rate ratio, and the pressure in the processing chamber  2  is set to a predetermined value by, for example, the exhaust device  18 . 
     Furthermore, in the substrate processing apparatus  1 , radio frequency powers having different frequencies are supplied from the first radio frequency power supply  21   a  and the second radio frequency power supply  21   b  to the base  11 . In addition, in the substrate processing apparatus  1 , a DC voltage is applied from the DC power supply  27  to the electrode plate  26  of the electrostatic chuck  25  to attract the substrate W to the electrostatic chuck  25 . The processing gas injected from the shower head  24  is turned into plasma, and the substrate W is etched by radicals and ions in the plasma. 
     &lt;Ring Assembly&gt; 
     The ring assembly  5  according to the embodiment will be described in detail.  FIG. 2  is a cross-sectional view of the ring assembly  5  according to the embodiment. 
     The ring assembly  5  includes the edge ring  30 , the annular member  80 , and the conductive member  81 . 
     The edge ring  30  is an annular member. The edge ring  30  is made of a conductive material. The edge ring  30  is made of, for example, the same material as the substrate W. Specifically, the edge ring  30  is made of, for example, silicon (Si) or silicon carbide (SiC). Each surface of the edge ring  30  will be described. An upper surface  30   a  of the edge ring  30  is a surface exposed to plasma. An inner peripheral surface  30   b  of the edge ring  30  is a surface on the substrate W side supported on the electrostatic chuck  25 . A lower surface  30   c  of the edge ring  30  is a surface to be supported on the substrate support  10 . An outer peripheral surface  30   d  of the edge ring  30  is a surface opposite to the substrate W supported on the electrostatic chuck  25 . 
     The annular member  80  is disposed so as to cover an outer peripheral portion  301  of the edge ring  30 . The inner diameter of the annular member  80  is larger than the inner diameter of the edge ring  30  so that the annular member  80  covers the outer peripheral portion  301  of the edge ring  30 . In other words, the inside of the outer peripheral portion  301  (the left portion) of the edge ring  30  is not covered with the annular member  80 , as illustrated in, for example,  FIG. 2 . The annular member  80  is made of an insulating material. Specifically, the annular member  80  is made of, for example, silicon oxide (SiO 2 ). Each surface of the annular member  80  will be described. An upper surface  80   a  of the annular member  80  is a surface exposed to the plasma. An inner peripheral surface  80   b   1  of the annular member  80  is a surface on the substrate W side supported on the electrostatic chuck  25 . A lower surface  80   c   1  of the annular member  80  is a surface facing the upper surface  30   a  of the edge ring  30  and being disposed on the upper surface  30   a  of the edge ring  30 . An inner peripheral surface  80   b   2  of the annular member  80  is a surface that covers the outer peripheral surface  30   d  of the edge ring  30 . A lower surface  80   c   2  of the annular member  80  is a surface supported on the substrate support  10 . An outer peripheral surface  80   d  of the annular member  80  is a surface on the opposite side to the substrate W supported on the electrostatic chuck  25 . 
     The conductive member  81  is an annular member disposed on the substrate W side of the upper surface  80   a  of the annular member  80 . The conductive member  81  is provided from the end portion of the upper surface  80   a  of the annular member  80  on the inner peripheral surface  80   b   1  side. That is, the inner diameter of the annular member  80  and the inner diameter of the conductive member  81  are equal to each other. In this manner, the conductive member  81  covers the upper surface  80   a  of the annular member  80  overlapping with the edge ring  30  within a predetermined range from the inner diameter side. In addition, the radial width of the conductive member  81  is equal to the radial width of the overlapping portion between the edge ring  30  and the annular member  80 . Accordingly, the outer diameter of the conductive member  81  is smaller than the outer diameter of the annular member  80 . The radial dimension of the overlapping portion between the edge ring  30  and the annular member  80  is set as Lol, and the radial dimension from the end portion of the conductive member  81  on the inner peripheral surface  80   b   1  side is set as L. In the ring assembly  5  according to the embodiment, the length Lol and the length L are equal to each other. In addition, the length L may not be the same as the length Lol, and it is preferably that the length L is, for example, half or more of the length Lol. The conductive member  81  is made of a conductive material. Specifically, the conductive member  81  is made of, for example, silicon (Si) or silicon carbide (SiC). 
     &lt;Function and Effect&gt; 
     As illustrated in  FIG. 2 , the upper surface  30   a  of the outer peripheral portion  301  of the edge ring  30  is covered with the annular member  80 . That is, in the annular member  80 , an inner peripheral portion  801  is disposed on the edge ring  30 . In a case where the edge ring  30  is not covered with another member, as compared with the inner peripheral surface  30   b  side, the outer peripheral surface  30   d  side is worn out particularly quickly. In the ring assembly  5  according to the embodiment, the outer peripheral surface  30   d  side (outer peripheral portion  301 ) of the edge ring  30  is covered with the annular member  80 . Accordingly, it is possible to suppress the wear out of the outer peripheral surface  30   d  side (outer peripheral portion  301 ) of the edge ring  30 . 
     In addition, the conductive member  81  is provided on the annular member  80 , so that it is possible to reduce the wear out of the annular member  80 . In particular, the conductive member  81  covers at least the upper surface  80   a  of the annular member  80  from the inner diameter side. In this manner, it possible to suppress the wear out of the annular member  80  and the edge ring  30  due to the plasma. 
     Furthermore, the conductive member  81  is arranged on at least a portion of the upper surface  80   a  of the annular member  80 , which overlaps with the edge ring  30  in top plan view. Accordingly, the height of the upper surface  80   a  of the annular member  80  and the height of an upper surface  81   a  of the conductive member  81  from the substrate support  10  are higher than the height of the upper surface  30   a  of the edge ring  30 . The height of the upper surface  80   a  of the annular member  80  and the height of the upper surface  81   a  of the conductive member  81  from the substrate support  10  are heightened, so that the height of the sheath in the edge ring  30  and the annular member  80  is allowed to be higher than that of the sheath formed on the upper surface  30   a  of the edge ring  30 . By adjusting the height of the sheath in this manner, it is possible to adjust the angle of incidence of the ions that are incident on the periphery of the end portion of the substrate W and control the etching shape of the end portion of the substrate W. For example, in a case where the angle of incidence of ions is inclined inward in the initial state, the angle of incidence of ions can be adjusted vertically by applying the ring assembly  5  according to the embodiment. 
     In addition, the conductive member  81  is provided on the annular member  80 , so that the distance between the upper surface  81   a  of the conductive member  81  and the upper electrode (shower head  24 ) can be narrowed. Accordingly, since the plasma can be confined to the substrate W side, it is possible to suppress a decrease in the plasma density. 
     In the substrate processing apparatus  1 , the edge ring  30  and the annular member  80  are consumable parts that need to be replaced according to the usage time. The productivity is decreased because the apparatus is stopped during the replacement work of the consumable parts. In the ring assembly  5  according to the embodiment, the wear out of the annular member  80  and the edge ring  30  due to the plasma is suppressed, so that it is possible to lengthen the replacement cycle and increase the life cycle of the consumable parts. In addition, it is possible to improve the productivity by increasing the operating rate of the apparatus. 
     Herein, a ring assembly  5 Z according to Comparative Example will be described.  FIG. 5  is a cross-sectional view of the ring assembly  5 Z according to Comparative Example. In the ring assembly  5 Z according to Comparative Example, annular members  80 Z are provided side by side outside an edge ring  30 Z. The heights of an upper surface  30 Za of the edge ring  30 Z and an upper surface  80 Za of the annular member  80 Z from the substrate support  10  are the same as each other. In that case, for example, when the upper surface  30 Za of the edge ring  30 Z is worn out, the height of the sheath is shortened. When the upper surface  30 Za of the edge ring  30 Z is worn out and the height of the sheath is shortened, the angle of incidence of ions of the periphery of the end portion of the substrate W is changed. Meanwhile, in the ring assembly  5  according to the embodiment, the angle of incidence of ions is adjusted to a desired substantially vertical angle, and the annular member  80  and the conductive member  81  are provided. Therefore, as compared with a case where the annular member  80  and the conductive member  81  are not provided, the distance between the annular member  80  and the upper electrode (shower head  24 ) and the distance between the conductive member  81  and the upper electrode can be shortened. Accordingly, the function of confining the plasma inside the edge ring  30  can be enhanced, and thus, it is possible to suppress the decrease in plasma density. It is possible to achieve both the adjustment of the angle of incidence of the ions and the suppression of the decrease in the plasma density. 
     In addition, for example, silicon oxide which is the material of the annular member  80  has an etching rate with respect to plasma of about eight times faster than that of silicon which is the material of the conductive member  81 . Therefore, the annular member  80  made of silicon oxide is likely to be worn out. In particular, the substrate W side (inner peripheral portion  801 ) where the annular member  80  overlaps with the edge ring  30  is likely to be etched. This is because the collision energy of the plasma is large in the portion overlapping with the edge ring  30 . In the ring assembly  5  according to the embodiment, the conductive member  81  is provided in the portion overlapping with the edge ring  30 , so that the wear out of the annular member  80  can be suppressed. Therefore, the replacement cycle of the annular member  80  and the edge ring  30  can be lengthened. 
     MODIFIED EXAMPLE 1 
       FIG. 3  is a cross-sectional view of a ring assembly  5 A that is Modified Example of the ring assembly  5  according to the embodiment. 
     In the ring assembly  5 A, an outer peripheral portion  301 A of an edge ring  30 A becomes thin. Specifically, an upper surface  30 Aa 1  is higher than an upper surface  30 Aa 2 . In an annular member  80 A, a portion (inner peripheral portion  801 A) that overlaps with the edge ring  30 A with respect to the annular member  80  becomes thick. In addition, a conductive member  81 A is provided on an upper surface  80 Aa of the annular member  80 A. The conductive member  81 A covers the entire upper surface of the annular member  80 A that overlaps with the edge ring  30 A in top plan view. 
     In this manner, by allowing the outer peripheral portion  301 A of the edge ring  30 A to be thin to provide a step difference, it is possible to achieve adjustment of the angle of incidence of ions and suppression of the decrease in the plasma density as in the above-described embodiment. Furthermore, it is possible to easily perform position alignment of the edge ring  30 A and the annular member  80 A. 
     MODIFIED EXAMPLE 2 
       FIG. 4  is a cross-sectional view of a ring assembly  5 B that is Modified Example of the ring assembly  5  according to the embodiment. 
     In the ring assembly  5 B, an annular member  80 B is provided on an upper surface  30 Ba of an edge ring  30 B. In addition, a conductive member  81 B is provided on an upper surface  80 Ba of the annular member  80 B. 
     As described above, the annular member  80 B is provided on the upper surface  30 Ba of the edge ring  30 B, so that it is possible to further increase the radial size of the edge ring  30 B. The conductive member  81 B covers a portion of the upper surface of the annular member  80 B that overlaps with the edge ring  30 B in top plan view. The range in which the conductive member  81 B covers the annular member  80 B may be determined according to the worn-out state of the annular member  80 B. The substrate W side of the annular member  80 B, which overlaps with the edge ring  30 , is likely to be etched. Therefore, the inside of the conductive member  81 B, which is likely to be etched, is covered with the conductive member  81 B. In addition, since the product occurring in the process is deposited on the outside of the annular member  80 B, the outside of the annular member  80 B may not be covered with the conductive member  81 B. 
     MODIFIED EXAMPLE 
     Although the conductive member  81  according to the embodiment has an annular shape, the shape is not limited thereto. For example, an arc-shaped conductive member  81  may be provided in a portion in the circumferential direction according to the angle of incidence of ions and the degree of wear out of the annular member  80 . In addition, the radial dimension from the end portion of the conductive member  81  on the inner peripheral surface  80   b   1  side, the length L, may be determined so as to cover the worn-out portion according to the worn-out situation of the annular member  80 . In addition, the edge ring  30  and the annular member  80  are not limited to an integral member, but may be configured with a plurality of members. 
     In addition, it should be understood that the ring assembly, the substrate support, and the substrate processing apparatus according to the above-described embodiments are examples in all respects and are not restrictive. The above-described embodiments can be modified and improved in various forms without departing from the scope and spirit of the appended claims. The matters described in the above-described plurality of embodiments can have other configurations as long as the configurations do not conflict with each other, and the matters can be combined with each other as long as the configurations do not conflict. 
     The substrate processing apparatuses according to the disclosure can be applied to any type of a capacitively coupled plasma (CCP), an inductively coupled plasma (ICP), a radial line slot antenna (RLSA), an electron cyclotron resonance plasma (ECR), or a helicon wave plasma (HWP). 
     According to the disclosure, adjustment of an angle of incidence of ions is achieved. 
     From the foregoing, it will be appreciated that various embodiments of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope and spirit being indicated by the following claims.