JP5975128B2 - Substrate processing apparatus and substrate processing method - Google Patents

Description

  The present invention relates to an etching method, an etching apparatus, and a ring member used in the etching method for etching a substrate by converting a processing gas into plasma.

  In a process of forming a multilayer wiring structure of a semiconductor device, a damascene recess including grooves and via holes is formed in various films formed on a semiconductor wafer (hereinafter referred to as “wafer”) made of, for example, Si (silicon). Plasma etching may be performed.

  The apparatus for performing the plasma etching process includes a mounting table on which the wafer is mounted, and a focus ring provided on the outer periphery of the wafer mounted on the mounting table. This focus ring is provided in order to distribute plasma with high uniformity on the wafer surface. In order to obtain such a high uniformity of plasma distribution, it is possible to configure the electrical characteristics such as the electrical conductivity of the focus ring to approximate the electrical characteristics such as the electrical conductivity of the wafer. It was considered effective. Therefore, the focus ring may be uniformly composed of the same Si as the material constituting the wafer.

  By the way, there are various materials for the etching target film exposed on the wafer surface. If the material constituting the film to be etched is different from the material constituting the focus ring, the reactivity of the active species of the plasma differs depending on the material, so that the diameter of the wafer is near the boundary between the wafer and the focus ring. The distribution of the active species contained in the plasma becomes uneven with respect to the inner side in the direction. As a result, the present inventor has found that the etching rate at the outer edge portion of the wafer increases or decreases with respect to the etching rate at the central portion of the wafer.

  Patent Documents 1 and 2 describe a plasma etching apparatus provided with a focus ring, but do not describe means for solving the above problems.

JP2006-140423 JP 2008-78208 A

  The present invention has been made on the basis of the above-mentioned circumstances, and the problem is to perform etching processing with high uniformity on the substrate when the etching gas on the substrate is dry-etched by converting the processing gas into plasma. Is to provide technology that can

The substrate processing apparatus of the present invention is a substrate processing apparatus for dry etching a film to be etched on a substrate in a vacuum atmosphere.
An etching module comprising a first processing vessel;
A film forming module including a second processing container;
A transfer chamber interposed between the first processing container and the second processing container and partitioned with respect to the first processing container and the second processing container;
With
The etching module is
A first stage on which the substrate is placed in the first processing container; a processing gas supply unit for supplying a processing gas into the first processing container; A plasma forming portion for etching the film to be etched, and a first exhaust path for evacuating the first processing container to form a vacuum atmosphere for performing the etching,
The substrate processing apparatus includes:
A ring member that is transported between the etching module and the film forming module and disposed on the first mounting table so as to surround the substrate on the first mounting table;
The film forming module includes:
A second mounting table on which the ring member is mounted in the second processing container; and at the time of etching in the etching module, the vicinity of the boundary between the substrate and the ring member and the central portion side of the substrate. In order to suppress uneven distribution of active species generated by the plasma and perform etching processing with high uniformity in the plane of the substrate, the surface of the ring member when etching the film to be etched is the film to be etched. A film forming mechanism for forming a film by supplying a film forming gas to the surface of the ring member so that the material is made of the same main component as the main component, and a second structure for performing film forming with the film forming gas. A second exhaust path for evacuating the processing container to form a vacuum atmosphere;
With
The transfer chamber is
A transport mechanism for transporting the ring member between the first processing container and the second processing container, and transporting the substrate from the transport chamber to the first processing container;
A film forming step of supplying the film forming gas to the ring member in the film forming module to form a film, and the ring member formed with the film forming gas by the transport mechanism from the second processing container. Transferring to the first processing container and placing on the first mounting table; loading the substrate into the first processing container and placing the substrate on the first mounting table; A control unit that outputs a control signal so as to perform the steps of introducing the processing gas into the first processing container, converting the processing gas into plasma, and etching the film to be etched with plasma of the processing gas Is provided

The substrate processing method of the present invention is a substrate processing apparatus for dry etching a film to be etched on a substrate in a vacuum atmosphere ,
An etching module comprising a first processing vessel;
A film forming module including a second processing container;
A transfer chamber interposed between the first processing container and the second processing container and partitioned with respect to the first processing container and the second processing container;
With
The etching module is
A first stage on which the substrate is placed in the first processing container; a processing gas supply unit for supplying a processing gas into the first processing container; A plasma forming portion for etching the film to be etched, and a first exhaust path for evacuating the first processing container to form a vacuum atmosphere for performing the etching,
The substrate processing apparatus includes:
A ring member that is transported between the etching module and the film forming module and disposed on the first mounting table so as to surround the substrate on the first mounting table;
The film forming module includes:
A second mounting table on which the ring member is mounted in the second processing container; and at the time of etching in the etching module, the vicinity of the boundary between the substrate and the ring member and the central portion side of the substrate. In order to suppress uneven distribution of active species generated by the plasma and perform etching processing with high uniformity in the plane of the substrate, the surface of the ring member when etching the film to be etched is the film to be etched. A film forming mechanism for forming a film by supplying a film forming gas to the surface of the ring member so that the material is made of the same main component as the main component, and a second structure for performing film forming with the film forming gas. A second exhaust path for evacuating the processing container to form a vacuum atmosphere;
With
The transfer chamber is
A substrate processing apparatus including a transport mechanism for transporting the ring member between the first processing container and the second processing container and transporting the substrate from the transport chamber to the first processing container is used. In the substrate processing method ,
Evacuating the inside of the second processing container via the second exhaust passage, and supplying the film forming gas to the ring member in the film forming module to form a film;
Transporting the ring member deposited with the deposition gas by the transport mechanism from the second processing container to the first processing container and placing the ring member on the first mounting table;
Carrying the substrate into the first processing container and placing the substrate on the first mounting table;
Said first processing chamber is evacuated through the first exhaust passage, by introducing the process gas into the first processing chamber into plasma the process gas, wherein the plasma of the process gas Etching the film to be etched;
It is characterized by providing.

According to the present invention, by supplying a deposition gas to the ring member for enclosing the substrate, the main component of the surface of the ring member from the same material as the main component of the film to be etched of the substrate, the process gas into plasma the The film to be etched on the substrate is etched. Accordingly, the uneven distribution of the active species of plasma between the center portion of the substrate and the outer edge portion of the substrate can be suppressed, and the substrate can be etched with high uniformity.

It is a vertical side view of the plasma etching apparatus according to the present invention. It is a vertical side view of the wafer surface etched by the plasma etching apparatus. It is process drawing which shows the process sequence in the said plasma etching apparatus. It is process drawing which shows the process sequence in the said plasma etching apparatus. It is explanatory drawing which shows a mode that the wafer W and a focus ring are etched. 1 is a plan view of a semiconductor manufacturing apparatus according to the present invention. It is a vertical side view of the mounting base provided in the said semiconductor manufacturing apparatus. It is explanatory drawing which shows a mode that a wafer is delivered between the said mounting base and a conveyance means. It is a vertical side view of the focus ring standby module provided in the semiconductor manufacturing apparatus. It is a vertical side view which shows the other structural example of a focus ring. It is explanatory drawing which shows the result of simulation. It is explanatory drawing which shows the result of simulation. It is explanatory drawing which shows the result of simulation. It is explanatory drawing which shows the result of simulation.

(First embodiment)
The plasma etching apparatus 1 according to the present invention will be described below. The plasma etching apparatus 1 is a magnetron type reactive ion etching apparatus. In the figure, reference numeral 1 denotes an airtight processing container made of a conductive member such as aluminum, and the processing container 10 is grounded. Further, in the processing vessel 10, an upper electrode 2 that also serves as a gas shower head, which is a gas supply unit for introducing a processing gas for performing etching, and a mounting table 3 that also serves as a lower electrode are opposed to each other. Is provided. A wafer W made of silicon, which is a substrate, is placed on the mounting table 3.

  An exhaust pipe 11 is connected to the bottom of the processing vessel 10, and a vacuum pump 12 such as a turbo molecular pump or a dry pump is connected to the exhaust pipe 11. Further, an opening 13 a for loading or unloading the wafer W is provided on the side wall of the processing container 10, which includes a gate valve 13 that can be freely opened and closed.

  On the lower surface side of the upper electrode 2, a number of gas discharge ports 22 communicating with the gas supply path 21, for example, piping and the buffer chamber 21 a are formed, and the wafer W placed on the mounting table 3 is formed. A predetermined processing gas can be discharged toward the front. The gas supply path 21 is connected to the gas supply system 23 at the base end side. The gas supply system 23 supplies a processing gas supply source for forming various films on the surface of the focus ring 4 to be described later, and an etching processing gas for etching the wafer W. A supply source. The processing gas supplied from each gas supply source will be described in detail later. The gas supply system 23 includes supply control devices such as a valve and a flow rate adjusting unit, and can supply each processing gas into the processing container 10.

  The upper electrode 2 is connected to a high frequency power supply unit 26 for supplying high frequency power via a matching unit 25. The upper electrode 2 is insulated from the side wall portion of the processing vessel 10 by an insulating member 27.

  The mounting table 3 includes a main body portion 30 made of a conductive member such as aluminum, and an electrostatic chuck 31 provided on the main body portion 30. For example, a foil-like electrode 31a is provided inside the electrostatic chuck 31, and a DC power source 33 is connected to the electrode 31a via a switch 32, and a static voltage is applied by applying a DC voltage (chuck voltage). The wafer W is electrostatically attracted to the surface of the electrostatic chuck 31 by the electric power. Although not shown in the figure, temperature adjusting means for adjusting the temperature is provided in the main body portion 30, and the wafer W is maintained at a preset temperature by the temperature adjusting action of the temperature adjusting means and the heat from the plasma. Will be.

  Further, a heat transfer gas such as helium gas (He) for increasing the heat transfer efficiency of a slight gap formed between the mounting table 3 and the wafer W is provided on the back surface of the wafer W on the surface of the electrostatic chuck 31. A large number of discharge ports 34 are formed to inject toward the outside and spread the heat transfer gas from the center. These discharge ports 34 communicate with a heat transfer gas supply unit 36 through a heat transfer gas supply path 35 that passes through the mounting table 3. Further, a high frequency power supply unit 38 for applying bias power is connected to the mounting table 3 via a matching unit 37. In addition, inside the mounting table 3, lifting pins (not shown) capable of delivering the wafer W to a transfer arm (not shown) are provided.

  A focus ring 4 made of Si is provided around the electrostatic chuck 31 so as to surround the periphery of the wafer W attracted and held by the electrostatic chuck 31. An insulating protective ring 39 for protecting screws and the like of the assembly is provided on the upper portion of the main body portion 30 of the mounting table 3, and the focus ring 4 extends over the protective ring 39 and the main body portion 30. In addition, a step portion is formed on the inner edge, and is formed in a shape that bites into the lower side of the wafer peripheral portion protruding outward from the mounting table 3.

  In order to prevent reaction products from adhering to the inner wall surface, a protective cylinder 51 made of, for example, quartz is provided on the inner wall of the processing vessel 10, and the side surface of the mounting table 3 is also provided. In addition, a cover body 52 for preventing adhesion of reaction products is provided. Reference numeral 53 denotes a baffle plate, which is intended to make the vacuum exhaust uniform. Further, on the outer peripheral side of the processing container 2, magnet portions 54 and 55 each including, for example, a large number of permanent magnets arranged in a ring shape are provided in order to form a predetermined magnetic field in the processing atmosphere.

  The plasma etching apparatus 1 includes a control unit 50 that controls the operation of each unit. The control unit 50 includes, for example, a computer having a CPU and a program (not shown). The program includes operations necessary for performing an etching process on the wafer W by the plasma etching apparatus 1, for example, each gas from the gas supply system 23. A group of steps (commands) for control and the like related to supply and power supply from the high-frequency power supply units 25 and 38 is assembled. This program is stored in a storage medium such as a hard disk, a compact disk, a magnetic optical disk, or a memory card, and installed in the computer therefrom.

  The operation of the above-described plasma etching apparatus 1 will be described. Here, a process is shown in which a wafer W on which a silicon film is formed is carried in, and after the silicon film is etched, for example, a wafer W on which an organic film is formed is carried in and the organic film is etched. For convenience of explanation, the wafer W on which the silicon film is etched is denoted as W1, and the wafer W on which the organic film is etched is denoted as W2.

  2A and 2B show the longitudinal side surfaces of the surfaces of the wafers W1 and W2. In the wafer W1, a silicon oxide film 62 and a SiN (silicon nitride) film 63 are stacked in this order on the silicon film 61 from below. The oxide film 62 and the SiN film 63 are formed with a convex portion 64 and a groove-shaped opening 65. In the plasma etching apparatus 1, the silicon film 61 is etched using the silicon oxide film 62 and the SiN film 63 as a hard mask, and a pattern for embedding an oxide film for element isolation is formed.

On the wafer W2, an SiO ₂ film 71, an organic film 72 made of carbon, an SiO ₂ film 73, and a photoresist (PR) film 74 made of carbon are laminated in this order from the bottom. A pattern 75 is formed on the photoresist film 74, and the SiO ₂ film 73 is etched along the pattern 75. In the plasma etching apparatus 1, the organic film 72 and the photoresist film 74 are etched (ashed) to form a mask pattern on the organic film 72. This mask pattern is a pattern for etching the SiO ₂ film 71 to form contact holes and the like.

  3 and 4 are explanatory views showing how the surfaces of the mounting table 3 and the focus ring 4 are changed, and FIG. 5 is an explanatory view showing how the wafers W1 and W2 and the focus ring 4 are etched by plasma. FIG. The description will be given with reference to FIGS. First, the gate valve 13 of FIG. 1 is opened, and the wafer W1 is loaded into the processing container 10 by a transfer arm (not shown). Then, the wafer W1 is mounted on the surface of the mounting table 3 by an operation of a lifting pin (not shown), and a voltage is applied to the electrostatic chuck 31 to electrostatically attract the wafer W1, and then He gas, which is a heat transfer gas, is added. Supply to the back side of the wafer W1.

For example, CF ₄ gas, CO gas, O ₂ gas, and Ar gas are supplied as etching process gases while closing the gate valve 13 and maintaining the inside of the processing vessel 10 at a predetermined pressure. Each processing gas supplied into the processing container 10 flows radially outward along the surface of the wafer W <b> 1 and is exhausted from the periphery of the mounting table 3. Thereafter, the high-frequency power supply unit 26 is turned on, and a high-frequency voltage is applied between the upper electrode 2 and the mounting table 3 as the lower electrode, and each processing gas is turned into plasma (FIG. 3A). Furthermore, the bias voltage is applied to the wafer W1 by turning on the high frequency power supply unit 38, so that the active species 66 in the generated plasma P1 collides with the wafer W1 with high perpendicularity (FIG. 5A). .

  Here, the etching target film 61 exposed on the surface of the wafer W1 and the surface of the focus ring 4 around the wafer W1 are made of the same Si. Accordingly, as shown in FIG. 5A, the active species 66 of the plasma P1 etch the surface of the focus ring 4 in the same manner as the wafer W1. As a result, the uneven distribution of the active species 66 in the vicinity of the boundary between the focus ring 4 and the wafer W1 as described in the background art item can be suppressed. Therefore, the etching of the silicon film 61 proceeds with high uniformity over the entire surface of the wafer W1 by the active species 66.

Thereafter, the high frequency power supply units 25 and 38 are turned off, and the supply of each etching gas is stopped. The gate valve 13 is opened, the transfer arm enters the processing container 10, and the wafer W1 is transferred to the transfer arm by the lift pins. Then, after the transfer arm moves out of the processing container 10 while holding the wafer W1, a dummy wafer A for protecting the mounting table 3 during film formation is mounted on the mounting table 3 by the transfer arm. Thereafter, the gate valve 13 is closed, and the processing vessel 10 is maintained at a predetermined pressure, for example, 50 mTorr, while Ar gas, CxHy gas (x and y are natural numbers), and O ₂ gas are used as the processing gas for film formation. 10 is supplied.

  Subsequently, the high-frequency power supply unit 25 is turned on to supply power to the upper electrode 2 at 1000 W, for example, to generate plasma, and the high-frequency power supply unit 38 is turned on to apply a bias voltage to the mounting table 3 (FIG. 3). (B)). Active species of plasma P are deposited on the focus ring 4 of the mounting table 3, and the dummy wafer A and the focus ring 4 are covered with an organic (CxHyOz) film 60 as shown in FIG. (X, y, z are natural numbers)

For example, 180 seconds after the high frequency power supply units 25 and 38 are turned on, the high frequency power supply units 25 and 38 are turned off, and supply of Ar gas, CxHy gas (x and y are natural numbers), and O ₂ gas are stopped. To do. Then, the dummy wafer A is unloaded from the processing container 10 in the same manner as the wafer W1. Subsequently, similarly to the wafer W1, the wafer W2 is loaded into the processing container 10 and mounted on the mounting table 3. Thereafter, for example, Ar gas, O ₂ gas, and CO gas are supplied into the processing container 10 as etching processing gases, and these processing gases are turned into plasma in the same procedure as when the wafer W1 is processed.

  Here, the etched films 72 and 74 exposed on the surface of the wafer W2 and the surface of the focus ring 4 are made of the same carbon material. Therefore, the O radical 76 which is the active species of the generated plasma P2 etches the organic film 60 formed on the surface of the focus ring 4 like the photoresist film 74 and the organic film 72 which are the etching target films of the wafer W2. As a result, the uneven distribution of the O radical 76 in the vicinity of the boundary between the focus ring 4 and the wafer W2 is suppressed. The O radical 76 has high uniformity over the entire surface of the wafer W2, and the organic film 72 and the photoresist film 74 Etching proceeds (FIG. 5B). Thereafter, the high frequency power supply units 25 and 38 are respectively turned off, the supply of the etching gas is stopped, and the wafer W2 is unloaded from the processing container 10 in the same manner as the wafer W1.

  When the wafer W2 is further processed after the processing of the wafer W2, the film is formed in accordance with the film to be etched of the wafer W3 before the wafer W3 is loaded into the processing container 10. Supply the processing gas. Then, as in the case of processing the wafer W <b> 2, the processing gas is turned into plasma and a film is formed on the surface of the focus ring 4. The main component of the film formed on the focus ring 4 is the same as the main component of the film constituting the film to be etched. Thereafter, the wafer W3 is carried into the processing container 10 and plasma etching is performed in the same manner as when the wafer W2 is processed.

  Subsequently, in order to obtain a good plasma active species distribution as described above, the material of the film to be formed on the surface of the focus ring 4 will be described for each film to be etched of the wafer W to be processed. An example of an etching gas for etching each film to be etched is also shown. Although illustration of some gases is omitted in FIG. 1, the gas supply system 23 is a process gas for film formation (film formation gas) and a process gas for etching (etching gas) in the following cases. The etching gas and the film forming gas can be supplied into the processing chamber 10 according to the film to be etched of the wafer W.

Case A: When the organic film is a film to be etched
This organic film is a film containing carbon as a main component and an element such as hydrogen, oxygen, or fluorine as a subcomponent. The film to be formed on the focus ring 4 may be an organic film containing carbon as a main component in the same manner as the film to be etched, and may be CxHy in addition to the CxHyOz film mentioned in the above example. . In order to form the CxHy film, a mixed gas containing CH ₄ gas and H ₂ gas or a mixed gas containing C ₂ H ₂ gas and H ₂ gas is supplied. In order to form the CxHyOz film, a mixed gas containing CH ₄ gas, H ₂ gas and O ₂ gas may be supplied, or a mixed gas containing CH ₄ and H ₂ O may be supplied. . In this case A, an O-based gas containing oxygen is used as the etching gas.

Case B: When the Si film is a film to be etched
In this case, the surface of the focus ring 4 is made of Si as in the above example. Therefore, for example, the focus ring 4 in the bare state is used without forming a film as described above. Further, for example, SiN containing Si as a main component and N as a subcomponent may be formed on the focus ring 4. In this case B, for example, a fluorocarbon (CF) gas is used as the etching gas.

Case C: When the SiO ₂ film is a film to be etched
A film formed on the focus ring 4 is made of, for example, SiO ₂ . In order to form this SiO ₂ film, TEOS (tetraethoxysilane) is supplied. In this case C, the surface of the focus ring 4 may be made of Si as in the case B. Therefore, the exposed focus ring 4 may be used as in the case where the Si film 61 of the wafer W1 is etched. Further, for example, SiN containing Si as a main component and N as a subcomponent may be formed on the focus ring 4. In this case C, for example, the CF gas is used as the etching gas.

Case D: When the SiN film is a film to be etched
The film formed on the focus ring 4 is made of SiN, for example. In order to form this SiN film, a mixed gas consisting of HMDS (hexamethyldisilazane) gas and HN ₃ (hydrazoic acid) gas may be supplied, or SiH ₄ (monosilane) gas and N ₂ (nitrogen). You may supply the mixed gas which consists of gas. Also, it may be supplied mixed gas of SiH ₄ gas and NH ₃ (ammonia) gas. Similarly to the cases B and C, the surface of the focus ring 4 may be made of Si. Therefore, the exposed focus ring 4 may be used similarly to the cases B and C. Further, for example, SiO ₂ containing Si as a main component and O as a sub component may be formed on the focus ring 4. In this case D, for example, the CF gas is used as the etching gas.

Case E: When Al (aluminum) film is a film to be etched The film formed on the focus ring 4 is made of Al, for example. In order to form the Al film, DMAH (dimethylaluminum hydride) gas or TMA (trimethylaluminum) gas is used. Further, for example, AlN (aluminum nitride) containing Al as a main component and N as a subcomponent may be formed on the focus ring 4. In this case E, Cl (chlorine) -based gas or Br (bromine) -based gas is used as the etching gas.

Case F: When Cu (copper) film is a film to be etched A film formed on the focus ring 4 is made of Cu, for example. As the etching gas, a Cl (chlorine) -based gas or a Br (bromine) -based gas is used. In order to form a Cu film, Cu (hfac) TMVS gas is used. Further, for example, CuO (copper oxide) containing Cu as a main component and O as a subcomponent may be formed on the focus ring 4. In this case F, a Cl-based gas or a Br-based gas is used as an etching gas.

  According to the plasma etching apparatus 1 of the first embodiment, a film having the same main component as the film to be etched of the wafer W can be formed on the surface of the focus ring 4. Accordingly, when the film to be etched is etched, active species of plasma react between the film to be etched and the surface of the focus ring 4 in the same manner. As a result, the uneven distribution of the active species is suppressed in the vicinity of the boundary between the wafer W and the focus ring 4 and on the central portion side of the wafer W, so that etching processing with high uniformity is performed on the entire surface of the wafer W. be able to.

  By the way, the focus ring 4 may be composed of alumina or ceramics. However, as described in the background art section, the focus ring 4 is composed of Si having the same electrical characteristics as the wafer W. Can be controlled with high uniformity, and this is preferable in order to prevent the uneven distribution of plasma more reliably.

(Second Embodiment)
In the first embodiment, the film forming process on the focus ring 4 and the plasma etching process on the wafer W are performed in the same processing container, but they may be performed in different processing containers. The configuration of the semiconductor manufacturing apparatus 8 that performs the film formation and the etching separately as described above will be described with reference to FIG. The semiconductor manufacturing apparatus 8 is a first transfer chamber 81, load lock chambers 82 and 83, and a vacuum transfer chamber module constituting a loader module for loading and unloading a wafer W, which is a substrate for manufacturing a semiconductor device. A second transfer chamber 84. On the front surface of the first transfer chamber 81, a mounting table 85 on which a carrier C that stores a plurality of wafers W is mounted is provided.

  The front wall of the first transfer chamber 81 is provided with a gate door GT that is connected to the carrier C and is opened and closed together with the lid of the carrier C. Plasma etching modules 91 and 91, a focus ring film forming module 92, and a focus ring standby module 93 are airtightly connected to the second transfer chamber 84.

  An alignment chamber 94 for adjusting the direction of the wafer W is provided on the side surface of the first transfer chamber 81. The load lock chambers 82 and 83 are provided with a vacuum pump and a leak valve (not shown) so as to be switched between an air atmosphere and a vacuum atmosphere. That is, since the atmospheres of the first transfer chamber 81 and the second transfer chamber 84 are maintained in an air atmosphere and a vacuum atmosphere, the load lock chambers 82 and 83 transfer the wafer W between the transfer chambers. It has a role to adjust the atmosphere when doing.

  In the drawing, G denotes a gate valve (a partition valve) that partitions between the load lock chambers 82 and 83 and the first transfer chamber 81 or the second transfer chamber 84, or between the second transfer chamber 84 and each module. It is. Normally, the gate valve G is closed and opened when the wafer W is transferred between the chambers and between the modules and the second transfer chamber 84.

  The first transfer chamber 81 and the second transfer chamber 84 are provided with a first transfer means 86 and a second transfer means 87, respectively. The first transfer means 86 is an articulated transfer arm for transferring the wafer W between the carrier C and the load lock chambers 82 and 83 and between the first transfer chamber 81 and the alignment chamber 94. . The second transfer means 87 is an articulated transfer arm. The second transfer means 87 has a role of delivering the wafer W between the load lock chambers 82 and 83 and each module and delivering the focus ring 4 between each module.

  The semiconductor manufacturing apparatus 8 includes a control unit 80 configured in the same manner as the control unit 50 described above. The control unit 80 can perform the plasma etching process and transfer of the wafer W, and can transfer the focus ring 4. The operation of each part of the semiconductor manufacturing apparatus 8 is controlled so that it can be performed.

  In the semiconductor manufacturing apparatus 8, the wafer W is in the order of carrier C → first transfer chamber 81 → alignment chamber 2 → first transfer chamber 81 → load lock chamber 82 → second transfer chamber 84 → plasma etching module 91. Transported and subjected to plasma etching process. Thereafter, the wafer W is transferred from the plasma etching module 91 in the order of the second transfer chamber 84 → the load lock chamber 83 → the first transfer chamber 81 and returned to the carrier C.

  Next, the plasma etching module 91 will be described. The plasma etching module 91 is configured in substantially the same manner as the plasma etching apparatus 1 and will be described below with reference to FIG. A ring-shaped electrostatic chuck 101 is provided on the main body portion 30 of the mounting table 3 of the plasma etching module 91. For example, an electrode 102 is provided inside the electrostatic chuck 101, and a DC power source 104 is connected to the electrode 102 via a switch 103. Then, by applying a DC voltage (chuck voltage) to the electrode 102, the focus ring 4 is electrostatically attracted and fixed to the surface of the electrostatic chuck 101 by an electrostatic force.

  Further, for example, three elevating pins 105 are provided so as to penetrate the electrostatic chuck 101 in the thickness direction (only two are shown in the figure), and the elevating mechanism 106 causes the elevating pins 105 to be connected to the electrostatic chuck 101. Project to the surface. In a state where the switch 103 is turned off and the attracting force by the electrostatic chuck 101 is lost, the elevating pin 105 is raised as shown in FIG. The second transport means 87 can receive the focus ring 4 lifted in this way and transport it to another module.

  The plasma etching module 91 includes a gas supply system for supplying various etching gases into the processing vessel 10 as in the plasma etching apparatus 1, and performs a plasma etching process on the wafer W as in the first embodiment. be able to.

  The focus ring film forming module 92 is configured in the same manner as the plasma etching module 91, and the focus ring 4 is configured to be detachable from the mounting table 3. In addition, the focus ring film forming module 92 includes a gas supply system that supplies various film forming gases into the processing vessel 10 as in the plasma etching apparatus 1. In a state where the focus ring 4 is attracted to the electrostatic chuck 101 of the mounting table 3, the film forming gas is supplied and the film forming gas is turned into plasma as in the first embodiment, and the film is formed on the focus ring 4. Processing is performed.

  FIG. 9 shows a vertical side view of the focus ring standby module 93. The focus ring standby module 93 is provided with a plurality of shelves 94 on which the focus ring 4 is placed. The shelf 94 is provided with, for example, three support pins 95 that support the focus ring 4. When the second conveying means 87 that has entered the focus ring standby module 93 is moved up and down, the focus ring 4 is transferred between the support pins 95 provided on the shelf 94 and the second conveying means 87.

  For example, a shelf 94 on which the focus ring 4 is placed is determined in advance according to the film to be formed. Various films are formed in advance on each focus ring 4, and the shelf 94 corresponding to the film is placed on the shelf 94. It is placed and waits. Then, before the wafer W is carried into the second transfer chamber 84, the focus ring 4 on which a film corresponding to the film to be etched of the wafer W is formed is transferred from the focus ring standby module 83 to the second transfer means. 87. Thereafter, the second transfer means 87 carries the focus ring 4 into the plasma etching module 91, and the focus ring 4 is attached to the mounting table 3.

  When the lot of wafers W carried into the semiconductor manufacturing apparatus 8 is switched and the material of the film to be etched is changed, the focus ring 4 of the plasma etching module 91 is transferred from the mounting table 3 to the second transfer means 87. , Returned to the shelf 94. Then, the second transfer means 87 transfers another focus ring 4 from the shelf 94 to the mounting table 3 according to the film to be etched of the subsequent wafer W, and the focus ring 4 is attached to the mounting table 3. It is done.

  Also in the second embodiment, since the etching process is performed by forming a film having the same main component as the film to be etched of the wafer W on the focus ring 4, the etching is performed on the wafer W with high uniformity as in the first embodiment. Processing can be performed.

  In the first and second embodiments described above, a film 111 may be attached to the surface of the focus ring 4 as shown in FIG. . As the material of the film 111, the materials described in the above cases A to F are used according to the film to be etched. Further, when such a film 111 is used instead of forming a SiO2 film with a processing gas, the film 111 may be made of, for example, MSQ (methyl cissesquioxane). Further, when the film 111 is used instead of forming the SiN film, the film 111 is made of, for example, HMDS. When the film 111 is used instead of forming the CHxOy film, the film 111 may be made of, for example, PMMA (polymethyl methacrylate resin) or SILK (polyarylene hydrocarbon).

  Instead of forming the film on the focus ring 4, for example, as shown in FIG. 10B, a ring member 112 having the same main component as the etching target film may be provided inside the focus ring 4. In such a case, the ring member 112 controls the reaction of the plasma active species in the vicinity of the peripheral edge of the wafer, and the focus ring 4 controls the electric field around the wafer W. Highly active species of plasma can be distributed.

  Although the case where the wafer W is processed has been described, the present invention can also be applied to a case where a rectangular substrate such as a flat panel is processed. That is, the ring member composed of the same main component as the main component of the film to be etched may be round or rectangular. Therefore, the member or the film 111 which is formed so as to surround the substrate by supplying the various film forming gases around the substrate may be circular or rectangular. Further, when the ring member 112 separate from the focus ring 4 is provided as described above, the ring member 112 is not limited to a circular shape, and may be a square shape.

(Evaluation test)
Subsequently, an experiment by simulation that led the inventor to obtain the knowledge of the present invention will be described. In this simulation, an apparatus substantially the same as the plasma etching apparatus shown in the first embodiment was set. On the mounting table 3 of this apparatus, it was set that the wafer W on which (CH ₂ ) n which is an organic film was formed as a film to be etched was mounted. The diameter of the wafer W is 300 mm. The upper electrode 2 was set to supply O ₂ gas, CO gas, and Ar gas at 60 sccm, 100 sccm, and 450 sccm, respectively. The pressure in the processing container 10 obtained by evacuation was 2.0 Pa.

  In the etching of the organic film, the contribution of O (oxygen) radicals is large, so the reactivity γ with respect to O radicals on the surface of the focus ring 4 is changed, and the concentration distribution and flow (flux) of the O radicals in the processing container 11 are investigated Further, the etching rate within the surface of the wafer W was examined for each reactivity γ. When the reactivity γ is 0, the surface of the focus ring 4 and the O radical do not react at all, and the O radical reacts with the surface of the focus ring 4 like the wafer W as the reactivity γ approaches 1.

11 (a) and 11 (b) show the distribution of O radicals with isoconcentration lines when the reactivity γ is 0 and 0.25, respectively. In each experiment, O radicals are distributed in the range of 0.50 × 10 ⁻⁵ mol / m ^{3 to} 1.69 × 10 ⁻⁵ mol / m ³ . In the figure, the region R1 in which the concentration of O radical is 1.35 × 10 ⁻⁵ mol / m ³ or more is indicated by a mesh, which is lower than 1.35 × 10 ⁻⁵ mol / m ³ , and is 1.24 × 10. ^The region R2 which is ⁻⁵ mol / m ³ or more is indicated by a number of points. The region R3 in which the concentration of O radical is lower than 1.24 × 10 ⁻⁵ mol / m ³ and 1.02 × 10 ⁻⁵ mol / m ³ or more is shown with a number of points. The density of dots is smaller than that shown. The region R4 in which the O radical concentration is lower than 1.02 × 10 ⁻⁵ mol / m ³ and 0.90 × 10 ⁻⁵ mol / m ³ or more is indicated by hatching. The region R5 lower than 0.90 × 10 ⁻⁵ mol / m ³ is not hatched or dotted. 12A and 12B show the O radical concentration distribution when the reactivity γ is 0.5 and 1, respectively, as in FIG.

In this simulation, the flux in each part in the processing container is calculated. This flux is the unit area of O radicals and the amount of movement per time, and the unit is mol / m ² · sec. The calculated flux is indicated by an arrow in FIGS. 11 and 12, and the direction of the arrow indicates the direction in which the O radical flows. However, in these FIG. 11 and FIG. 12, for the convenience of illustration, the number of arrows is displayed smaller than the actually obtained simulation result. The arrows near the wafer W when γ = 0, γ = 0.25, and γ = 0.5 are shown more clearly in FIGS. 13A, 13B, and 13C, respectively. In FIG. 13, the length of the arrow indicates the magnitude of each point of the O radical flux value.

  As shown in FIGS. 11 to 13, when γ = 0, O radicals flow into the outer edge portion of the wafer W, and the concentration distribution of O radicals differs between the central portion and the outer edge portion of the wafer W. Yes. However, in the case of γ = 0.25, 0.5 and 1, the flow of O radicals to the outer edge of the wafer W is suppressed instead of the flow of O radicals into the focus ring 4 being increased. The uniformity of the O radical concentration distribution is high between the center and the outer edge of the wafer W.

  FIG. 14 is a graph showing the etching rate of the wafer W for each reactivity γ obtained by simulation. The vertical axis of the graph represents the etching rate (nm / min), and the horizontal axis represents the distance from the center of the wafer W. From this graph, it can be seen that the closer the reactivity due to O radicals in the focus ring 4 is to the reactivity due to O radicals in the wafer W, the higher the uniformity of the etching rate in the wafer W plane. From the simulation results shown in FIGS. 11 to 14, the present inventor improves the etching rate in the wafer W surface by arranging a ring member having the same main component as the film to be etched around the wafer W. I came up with it.

W Semiconductor wafer 1 Plasma etching apparatus 10 Processing vessel 2 Upper electrode 23 Gas supply system 26 High frequency power supply unit 3 Mounting table 38 High frequency power supply unit 4 Focus ring 50 Control unit 8 Semiconductor manufacturing apparatus 80 Control unit 91 Plasma etching module 92 Focus ring film formation module

Claims (6)

In a substrate processing apparatus for dry etching a film to be etched on a substrate in a vacuum atmosphere,
An etching module comprising a first processing vessel;
A film forming module including a second processing container;
A transfer chamber interposed between the first processing container and the second processing container and partitioned with respect to the first processing container and the second processing container;
With
The etching module is
A first stage on which the substrate is placed in the first processing container; a processing gas supply unit for supplying a processing gas into the first processing container; A plasma forming portion for etching the film to be etched, and a first exhaust path for evacuating the first processing container to form a vacuum atmosphere for performing the etching,
The substrate processing apparatus includes:
A ring member that is transported between the etching module and the film forming module and disposed on the first mounting table so as to surround the substrate on the first mounting table;
The film forming module includes:
A second mounting table on which the ring member is mounted in the second processing container; and at the time of etching in the etching module, the vicinity of the boundary between the substrate and the ring member and the central portion side of the substrate. In order to suppress uneven distribution of active species generated by the plasma and perform etching processing with high uniformity in the plane of the substrate, the surface of the ring member when etching the film to be etched is the film to be etched. A film forming mechanism for forming a film by supplying a film forming gas to the surface of the ring member so that the material is made of the same main component as the main component, and a second structure for performing film forming with the film forming gas. A second exhaust path for evacuating the processing container to form a vacuum atmosphere;
With
The transfer chamber is
A transport mechanism for transporting the ring member between the first processing container and the second processing container, and transporting the substrate from the transport chamber to the first processing container;
A film forming step of supplying the film forming gas to the ring member in the film forming module to form a film, and the ring member formed with the film forming gas by the transport mechanism from the second processing container. Transferring to the first processing container and placing on the first mounting table; loading the substrate into the first processing container and placing the substrate on the first mounting table; A control unit that outputs a control signal so as to perform the steps of introducing the processing gas into the first processing container, converting the processing gas into plasma, and etching the film to be etched with plasma of the processing gas A substrate processing apparatus, comprising: Connected to the transfer chamber is a standby chamber where the ring member is transferred by the transfer mechanism, the film forming module performs a film forming process, and the ring member waits before being transferred to the etching module. The substrate processing apparatus according to claim 1, wherein the substrate processing apparatus is provided.   The controller outputs a control signal so as to execute a step of transferring the dummy substrate into the second processing container by the transfer mechanism;
The film forming step is performed in a state where the dummy substrate is mounted on the second mounting table and the ring member is disposed on the second mounting table so as to surround the dummy substrate. The substrate processing apparatus according to claim 1, wherein the substrate processing apparatus is characterized.   An electrostatic chuck for attaching and detaching the ring member to and from the first mounting table and the second mounting table, respectively, on a peripheral portion of the first mounting table and a peripheral portion of the second mounting table. The substrate processing apparatus according to claim 1, wherein the substrate processing apparatus is provided. When the film to be etched is an organic film, the film formed on the surface of the ring member is an organic film, and when the film to be etched is a Si film, a SiO2 film, or a SiN film, a film formed on the surface of the ring member 5 is Si or SiN, and when the film to be etched is an Al film or a Cu film, the film formed on the surface of the ring member is an Al film or a Cu film . The substrate processing apparatus as described in one. A substrate processing apparatus for dry etching a film to be etched on a substrate in a vacuum atmosphere ,
An etching module comprising a first processing vessel;
A film forming module including a second processing container;
A transfer chamber interposed between the first processing container and the second processing container and partitioned with respect to the first processing container and the second processing container;
With
The etching module is
A first stage on which the substrate is placed in the first processing container; a processing gas supply unit for supplying a processing gas into the first processing container; A plasma forming portion for etching the film to be etched, and a first exhaust path for evacuating the first processing container to form a vacuum atmosphere for performing the etching,
The substrate processing apparatus includes:
A ring member that is transported between the etching module and the film forming module and disposed on the first mounting table so as to surround the substrate on the first mounting table;
The film forming module includes:
A second mounting table on which the ring member is mounted in the second processing container; and at the time of etching in the etching module, the vicinity of the boundary between the substrate and the ring member and the central portion side of the substrate. In order to suppress uneven distribution of active species generated by the plasma and perform etching processing with high uniformity in the plane of the substrate, the surface of the ring member when etching the film to be etched is the film to be etched. A film forming mechanism for forming a film by supplying a film forming gas to the surface of the ring member so that the material is made of the same main component as the main component, and a second structure for performing film forming with the film forming gas. A second exhaust path for evacuating the processing container to form a vacuum atmosphere;
With
The transfer chamber is
A substrate processing apparatus including a transport mechanism for transporting the ring member between the first processing container and the second processing container and transporting the substrate from the transport chamber to the first processing container is used. In the substrate processing method ,
Evacuating the inside of the second processing container via the second exhaust passage, and supplying the film forming gas to the ring member in the film forming module to form a film;
Transporting the ring member deposited with the deposition gas by the transport mechanism from the second processing container to the first processing container and placing the ring member on the first mounting table;
Carrying the substrate into the first processing container and placing the substrate on the first mounting table;
Said first processing chamber is evacuated through the first exhaust passage, by introducing the process gas into the first processing chamber into plasma the process gas, wherein the plasma of the process gas Etching the film to be etched;
A substrate processing method comprising:

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