JP5528391B2 - Substrate plasma processing method - Google Patents

Description

  The present invention relates to a method for performing plasma processing on a plurality of substrates that are transferred while being accommodated in a tray.

  In the manufacturing process of an LED device, in order to improve the external extraction efficiency of light from the device, an etching process (plasma process) is performed as a process of forming an uneven structure on the surface of the sapphire substrate. In such an etching process, a plurality of substrates are handled in a state of being accommodated in a tray (see, for example, Patent Document 1).

  Specifically, a plurality of substrate accommodation holes are formed in the tray, and the edges of the sapphire substrate are supported by the substrate support portion protruding from the inner wall of the substrate accommodation hole, so that the plurality of substrates are placed in the tray. It is configured to be accommodated. A substrate stage is disposed in the chamber of the plasma processing apparatus, and a tray support part and a plurality of substrate holding parts protruding upward from the tray support part are provided on the upper surface of the substrate stage.

  When performing the etching process, the plurality of substrates are loaded into the chamber while being accommodated in the tray, and the plurality of substrates are placed on the substrate holding unit by placing the tray on the tray support unit. At the same time, the edge of the substrate is separated from the substrate support. In such a state, each substrate is electrostatically attracted by an ESC (electrostatic chuck) built in the substrate holding unit, and the substrate is etched by the substrate holding unit. When the etching process is completed, the adsorption holding by the ESC is released, the tray is lifted from the tray support portion, and a plurality of substrates are carried out of the chamber in a state where the edge portion of the substrate is again supported by the substrate support portion.

JP 2007-109771 A

  However, in the etching method as disclosed in Patent Document 1, the edge of the substrate held by each substrate holding part in the substrate stage and the substrate support part in the tray are in a state of being separated from each other. By-products (depots) generated from a sapphire substrate and a tray (for example, formed of SiC) during processing adhere to the edge of the substrate and the inner wall of the substrate accommodation hole of the tray, resulting in product defects. There's a problem.

  Accordingly, an object of the present invention is to solve the above problems, and in a method for performing plasma processing on a plurality of substrates that are transported in a state of being accommodated in a tray, an edge portion of the substrate during plasma processing is provided. It is another object of the present invention to provide a plasma processing method for a substrate which can improve the quality of a product by removing a by-product attached to a tray.

  In order to achieve the above object, the present invention is configured as follows.

  According to the first aspect of the present invention, a plurality of substrate accommodation holes for accommodating a substrate are provided, and a tray having a substrate support portion protruding from the inner wall of the substrate accommodation hole is used. A substrate carrying-in process for carrying a plurality of substrates in a state of being supported and accommodated in the substrate accommodation holes into the chamber, a tray support portion and a plurality of substrate holding portions projecting upward from the tray support portion in the chamber, With respect to the substrate stage having a substrate, the substrate is supported on the edge of the substrate protruding from the edge of the substrate holding unit by placing the tray on the tray supporting unit and placing the substrate on each substrate holding unit. In the substrate placing process in which a gap is formed between the substrate and the tray, and in a state where the tray and each substrate are placed on the substrate stage, the processing gas is supplied into the chamber and the pressure in the chamber is The first plasma processing step of performing plasma processing on the respective substrates, and supplying the processing gas into the chamber and adjusting the pressure in the chamber to perform the plasma processing, and by performing the first plasma processing step A second plasma processing step for removing by-products attached to the edge of the substrate and the substrate supporting portion; and after completion of the second plasma processing step, with the substrate supporting portion supporting the edge of the substrate in the tray And a substrate unloading step of unloading each substrate from the chamber, and in the second plasma processing step, the tray is moved to a position that suppresses adhesion of by-products removed by the second plasma processing step to the substrate holder. Provided is a plasma processing method for a substrate, in which plasma processing is performed in an elevated state.

  According to the second aspect of the present invention, when the second plasma processing step is performed after completion of the first plasma processing step, the processing gas is switched to a different type of processing gas from the processing gas in the first plasma processing step. The substrate plasma processing method according to the first aspect, wherein the second plasma processing step is performed at a pressure higher than the pressure in the one plasma processing step.

  According to the third aspect of the present invention, in the first plasma processing step, each substrate is attracted and held on the substrate holding portion by electrostatic attraction, and cooling supplied at a predetermined pressure between the substrate and the substrate holding portion. Plasma treatment is performed while cooling with gas, and when the second plasma treatment step is performed after the first plasma treatment step is finished, the drive voltage is switched to a drive voltage lower than the electrostatic adsorption drive voltage in the first plasma treatment step. The substrate plasma processing method according to the second aspect, wherein electrostatic adsorption is performed.

  According to the fourth aspect of the present invention, when performing the second plasma processing step, the substrate plasma processing method according to the third aspect is switched to a pressure lower than the pressure of the cooling gas in the first plasma processing step. provide.

  According to the fifth aspect of the present invention, the differential pressure between the electrostatic adsorption driving voltage and the pressure inside the chamber in the second plasma processing step and the cooling gas in performing the second plasma processing step is zero. The substrate plasma processing method according to the fourth aspect is provided.

  According to a sixth aspect of the present invention, in the third aspect, a sapphire substrate is used as the substrate, and in the first plasma processing step, a process of forming a minute uneven structure on the surface of the sapphire substrate is performed as plasma processing. A method for plasma processing a substrate is provided.

According to the seventh aspect of the present invention, a gas mainly composed of BCl ₃ is used as the processing gas in the first plasma processing step, and a mixed gas of O ₂ / fluorine gas is used as the processing gas in the second plasma processing step. A substrate plasma processing method according to an aspect is provided.

  According to the eighth aspect of the present invention, the position at which the by-product removed by the second plasma processing step is prevented from adhering to the substrate holding portion is a height at which the edge of the substrate is supported by the substrate support portion of the tray. The substrate plasma processing method according to the first aspect is provided.

  According to the ninth aspect of the present invention, before the second plasma processing step, the substrate is generated while performing the static elimination processing for generating the static elimination plasma and reducing the residual electrostatic attraction force between the substrate and the substrate holder. The substrate plasma processing method according to the eighth aspect, wherein the tray is raised to a height supporting the edge of the substrate.

  According to the tenth aspect of the present invention, the position at which the by-product removed by the second plasma processing step is prevented from adhering to the substrate holding portion is such that the substrate support portion of the tray does not contact the edge of the substrate. Provided is the substrate plasma processing method according to the first aspect, which is a height with a gap maintained.

  According to the eleventh aspect of the present invention, after the second plasma processing step is completed, the plasma is generated while performing the static elimination treatment for reducing the residual electrostatic adsorption force between the substrate and the substrate holding portion by generating the static elimination plasma. The substrate plasma processing method according to the tenth aspect, wherein the substrate plasma processing method causes the substrate to float from a holding surface of the substrate holding unit.

  According to the present invention, in the substrate placement step of the plurality of substrates on the substrate stage in the chamber, the edge of the substrate protruding from the end of the substrate holding portion and the substrate support portion of the tray are separated, In this state, the first plasma processing step is performed, and then, by-products attached to the edge of the substrate and the substrate support portion by performing the first plasma processing step are removed by performing the second plasma processing step. can do. In addition, in the second plasma processing step, the plasma processing is performed in a state in which the gap between the edge of the substrate and the substrate support portion is reduced or eliminated, so that it is removed in the second plasma processing step. It is possible to suppress the by-product from reattaching to the side surface of the substrate holder. Therefore, the quality of the product in the plasma processing method for a substrate can be improved, and the maintenance frequency of the plasma processing apparatus can be reduced.

1 is a configuration diagram of a dry etching apparatus according to a first embodiment of the present invention. Perspective view of tray, substrate and substrate stage Perspective view of tray, substrate and substrate stage (tray placement state) Sectional view showing relationship between tray and substrate and stage top Block diagram showing the main configuration of the control unit provided in the dry etching device The flowchart which shows the procedure of the etching processing method of Embodiment 1. Explanatory drawing which shows the adhesion state of a deposit ((B) is a decomposition state) Explanatory drawing which shows the tray at the time of the cleaning process of Embodiment 1, a board | substrate, and a substrate stage. Operation explanatory diagram showing the procedure of tray carry-out processing Explanatory drawing which shows the tray at the time of the cleaning process of Embodiment 2 of this invention, a board | substrate, and a substrate stage.

  Embodiments according to the present invention will be described below in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 shows a configuration diagram of an ICP (inductively coupled plasma) type dry etching apparatus 1 as an example of a plasma processing apparatus according to Embodiment 1 of the present invention.

The dry etching apparatus 1 includes a chamber (vacuum container) 3 that constitutes a processing chamber in which plasma processing is performed on the substrate 2. The upper end opening of the chamber 3 is closed in a sealed state by a top plate 4 formed of a dielectric such as quartz. The lower surface side of the top plate 4 is covered with a top plate cover portion 6 formed of a dielectric. An ICP coil 5 is disposed on the top plate 4, and the ICP coil 5 is covered with a coil cover portion 10. The ICP coil 5 is electrically connected to a first high frequency power supply unit 7 including a matching circuit. A substrate stage 9 having a function as a lower electrode to which a bias voltage is applied and a function as a holding table for the substrate 2 is disposed on the bottom side in the chamber 3 facing the top plate 4. The chamber 3 is provided with a gate valve 3a that can be opened and closed that communicates with, for example, a load dock chamber (not shown), and the substrate 2 is held and opened by a hand unit provided in a transfer mechanism (not shown). The loading / unloading operation of the substrate 2 is performed through the gate valve 3a in the state. A gas supply unit 12 is connected to an etching gas inlet 3 b provided in the chamber 3. The gas supply unit 12 includes a plurality of types of gas supply lines (for example, BCl ₃ , Cl ₂ , Ar, O ₂ , CF ₄ ), and an open / close valve provided for each gas type line. By selectively controlling the opening / closing operation and the opening degree of 12a, 12b and the flow rate adjusting unit 12c, a processing gas having a desired flow rate and specifications can be supplied from the gas introduction port 3b. Further, a pressure control unit 13 including a vacuum pump, a pressure control valve, and the like is connected to the exhaust port 3 c provided in the chamber 3.

  Next, the tray 15 holding the substrate 2 handled by the dry etching apparatus 1 of Embodiment 1 will be described with reference to the schematic perspective views of FIGS.

The tray 15 includes a thin disc-shaped tray body 15a. Examples of the material of the tray 15 include ceramic materials such as alumina (Al ₂ O ₃ ), aluminum nitride (AlN), zirconia (ZrO), yttria (Y ₂ O ₃ ), silicon nitride (SiN), and silicon carbide (SiC). There are also metals such as aluminum coated with alumite, aluminum coated with ceramics on the surface, and aluminum coated with a resin material. It is conceivable to employ alumina, yttria, silicon carbide, aluminum nitride or the like in the case of a Cl-based process, and aluminum or the like which applies quartz, quartz, yttria, silicon carbide, anodized or the like in the case of an F-based process. In the first embodiment, a tray 15 formed using silicon carbide as a main material is used.

  The tray body 15a is provided with four substrate accommodation holes 19 penetrating in the thickness direction from the upper surface 15b to the lower surface 15c. The substrate accommodation holes 19 are arranged at equiangular intervals with respect to the center of the tray main body 15a when viewed from the upper surface 15b and the lower surface 15c. As shown in detail in FIGS. 4A and 4B, the inner wall 15d of each substrate housing hole 19 is provided with a substrate support portion 21 protruding toward the center of the hole. In this Embodiment 1, the board | substrate support part 21 is provided in the perimeter of the inner wall 15d, and is annular | circular shape by planar view.

  Each substrate accommodation hole 19 accommodates a single substrate 2. The lower surface portion of the outer peripheral edge 2 a of the substrate 2 accommodated in the substrate accommodating hole 19 is supported by the upper surface 21 a of the substrate support portion 21. Further, since the substrate accommodation hole 19 is formed so as to penetrate the tray main body 15a in the thickness direction, the lower surface of the substrate 2 is exposed by the substrate accommodation hole 19 when viewed from the lower surface side of the tray main body 15a. Yes.

  The tray main body 15a is formed with a notch 15e with a part of the outer peripheral edge notched, and when the tray 15 is handled during transport or the like, the orientation of the tray 15 can be easily confirmed using a sensor or the like.

  Next, the substrate stage 9 will be described with reference to FIGS.

  As shown in FIG. 1, the substrate stage 9 is formed of a stage upper part 23 formed of a dielectric member such as ceramics, and aluminum having alumite coating on the surface and functions as a lower electrode to which a bias voltage is applied. A metal block 24, an insulator 25, and a metal shield 27. The stage upper part 23 arranged at the uppermost part of the substrate stage 9 is fixed to the upper surface of the metal block 24, and the outer periphery of the stage upper part 23 and the metal block 24 is covered with the insulator 25, and the outer periphery of the insulator 25 is further covered. Is covered with a shield 27 made of metal.

  As shown in FIG. 2, the stage upper portion 23 is formed in a disk shape, and the upper end surface of the stage upper portion 23 is a tray support portion 28 that supports the lower surface 15 c of the tray 15. Further, four short cylindrical substrate holding portions 29 corresponding to the respective substrate accommodation holes 19 of the tray 15 protrude upward from the tray support portion 28. Further, an annular guide ring 30 is disposed on the stage upper portion 23 so as to surround the tray support portion 28 and protrudes upward from the stage upper portion 23. The guide ring 30 plays a role of guiding the arrangement position of the tray 15 in the stage upper part 23.

  Here, the relationship among the tray 15, the substrate 2, the substrate holding portion 29, and the like will be described with reference to FIGS. 4 (A) and 4 (B). The outer diameter R1 of the substrate holding part 29 is set smaller than the inner diameter R2 of the front end face (inner peripheral end face) 21b of the substrate support part 21. Therefore, in a state where the tray 15 is disposed on the tray support portion 28, a gap is secured between the substrate support portion 21 formed in the substrate accommodation hole 19 and the substrate holding portion 29 so as not to contact each other. The

  The height H1 from the lower surface 15c of the tray main body 15a to the upper surface 21a of the substrate support portion 21 is set to be lower than the height H2 from the tray support portion 28 to the holding surface 31 of the substrate holding portion 29. Therefore, in a state where the lower surface 15c of the tray 15 is disposed on the tray support portion 28, the substrate 2 is pushed up by the holding surface 31 of the substrate holding portion 29, and the substrate 2 is lifted from the substrate support portion 21 of the tray 15. Become. In other words, when the tray 15 that accommodates the substrate 2 in the substrate accommodation hole 19 is arranged on the upper stage 23, the substrate 2 accommodated in the substrate accommodation hole 19 is lifted from the upper surface 21 a of the substrate support portion 21, and The lower surface of the substrate 2 is disposed on the holding surface 31 of the substrate holding portion 29 in a state where the edge portion 2 a and the upper surface 21 a of the substrate supporting portion 21 are separated from each other. As shown in FIGS. 3 and 4B, when the respective substrates 2 are arranged on the substrate holding portion 29 and are separated from the tray 15, the upper surface of the substrate 2 and the upper surface 15b of the tray 15 are It will be in the state located in the almost same height.

  Further, the outer diameter R1 of the substrate holding part 29 is set smaller than the outer diameter R3 of the substrate 2. Therefore, when the substrate 2 is disposed on the substrate holding portion 29 and is separated from the tray 15, the edge portion 2 a of the substrate 2 has a diameter larger than the outer peripheral end portion of the substrate holding portion 29 as shown in FIG. It is in a state of protruding outward in the direction.

  Further, as shown in FIG. 1, an ESC electrode (electrostatic chucking electrode) 40 is built in the vicinity of the holding surface 31 of each substrate holding unit 29 provided on the stage upper portion 23. These ESC electrodes 40 are electrically insulated from each other, and a DC voltage for electrostatic adsorption is applied from an ESC drive power supply unit 41 having a built-in DC power supply.

  As shown in FIG. 1, a cooling gas supply port 44 is provided on the holding surface 31 of each substrate holding unit 29, and each cooling gas supply port 44 is connected to a common cooling gas supply unit 47 through a cooling gas supply path 47. 45. In the first embodiment, helium (He) is used as the cooling gas, and the cooling gas is supplied between the holding surface 31 of the substrate holding unit 29 and the substrate 2 during the plasma processing, whereby the substrate 2 is heated. Cooling takes place.

  The metal block 24 is electrically connected to a second high frequency power supply unit 56 that applies a high frequency as a bias voltage. The second high frequency power supply unit 56 includes a matching circuit.

  In addition, a coolant channel 60 for cooling the metal block 24 is formed in the metal block 24, and the coolant whose temperature is adjusted by the cooling unit 59 is supplied to the coolant channel 60, so that the metal block 24 is cooled.

  As shown in FIG. 1, the substrate stage 9 includes a plurality of trays 15 that are arranged on the tray support portion 28 and are pushed up (push up) from the lower surface side to raise the respective substrates 2 together with the tray 15. A tray push-up rod 18 is provided. Each tray push-up rod 18 is driven up and down by the drive mechanism 17 between a push-up position protruding from the upper surface of the tray support portion 28 and a storage position stored in the tray support portion 28.

  Next, the configuration of the control unit 70 provided in the dry etching apparatus 1 will be described with reference to the block diagram shown in FIG.

  As shown in FIG. 5, the first high frequency power supply unit 7, the second high frequency power supply unit 56, the ESC drive power supply unit 41, the gate valve 3 a, the transport mechanism, and the drive, which are the respective components included in the dry etching apparatus 1. Operations of the mechanism 17, the gas supply unit 12, the cooling unit 59, and the pressure control unit 13 are controlled by the control unit 70 while being associated with the operations of the other components. Further, the control unit 70 is provided with an operation / input unit 71 for performing operations and inputs by an operator, and a display unit 72 for displaying operation information and the like in the dry etching apparatus 1.

  Further, in the dry etching apparatus 1 according to the first embodiment, for example, a sapphire substrate is handled as the substrate 2, and as a etching process (plasma process), a minute uneven structure (PSS: Patterned Sapphire) is formed on the surface of the sapphire substrate 2. Substrate) is performed. It should be noted that the processing for forming a minute concavo-convex structure on the surface of the substrate 2 in this way can also be referred to as roughening processing or surface texture processing of the substrate surface.

  In the dry etching apparatus 1, in order to perform such an etching process, a plurality of substrates 2 held on the tray 15 are loaded into the chamber 3 and placed on the substrate stage 9 (substrate loading process). And substrate mounting step), etching processing (first plasma processing step) for performing PSS processing on the loaded substrate 2 by etching processing, and by-products attached to the substrate 2 and the tray 15 by performing the etching processing. Cleaning treatment (second plasma treatment step) for removing the plasma by a plasma treatment, a static elimination treatment (static elimination step) for generating a static elimination plasma to reduce the residual electrostatic attraction between the substrate 2 and the substrate holding portion 29, A tray unloading process (substrate unloading process) for unloading from the chamber 3 with each substrate 2 held on the tray 15 is set in advance. It carried out continuously by executing the program. Therefore, the control unit 70 includes these programs and a calculation unit that executes the programs, and a transfer processing unit 73, an etching processing unit 74, a cleaning processing unit 75, and a charge removal processing unit as processing units that execute various processes. 76 is provided. Further, the control unit 70 is provided with an operation condition storage unit 77 that stores various operation conditions for performing the etching process, the cleaning process, and the charge removal process.

  Next, a method for performing an etching process on a plurality of substrates 2 using the dry etching apparatus 1 having the above-described configuration will be described with reference to a flowchart shown in FIG. In addition, each process demonstrated below is implemented by controlling each structure part based on the program and driving | running condition which were preset by the control part 70 with which the dry etching apparatus 1 is provided.

(Tray import processing)
First, the tray carry-in process (step S1) in the flowchart of FIG. 6 is performed. Specifically, in the dry etching apparatus 1, the gate valve 3a is opened. Thereafter, the tray 15 in which the substrates 2 are accommodated in the four substrate accommodation holes 19 is held by the hand portion of the transport mechanism, and is carried into the chamber 3 from the load lock chamber through the gate valve 3a, for example. .

  In the chamber 3, the tray push-up rod 18 driven by the drive mechanism 17 rises, and the tray 15 is transferred from the hand portion to the upper end of the tray push-up rod 18. After the transfer of the tray 15, the hand unit is retracted to the load lock chamber, and the gate valve 3a is closed.

  The tray push-up rod 18 that supports the tray 15 at the upper end descends from the push-up position toward the storage position stored in the substrate stage 9. The lower surface 15 c of the tray 15 is lowered to the tray support portion 28 of the stage upper portion 23 of the substrate stage 9, and the tray 15 is supported by the tray support portion 28 of the stage upper portion 23. When the tray 15 descends toward the tray support portion 28, the substrate holding portion 29 of the stage upper portion 23 enters the corresponding substrate accommodation hole 19 of the tray 15 from the lower surface 15c side of the tray 15. Before the lower surface 15 c of the tray 15 contacts the tray support portion 28, the holding surface 31 that is the upper end surface of the substrate holding portion 29 contacts the lower surface of the substrate 2. When the tray 15 is further lowered and the lower surface 15c of the tray 15 is placed on the tray support portion 28, the edge 2a of each substrate 2 is lifted from the upper surface 21a of the substrate support portion 21, and the tray 15, the substrate 2, A gap is formed between the two. Since the tray 15 is positioned by the guide ring 30, each substrate 2 is positioned with high positioning accuracy with respect to the substrate holding portion 29.

  Thereafter, a DC voltage (drive voltage) is applied from the ESC drive power supply unit 41 to the ESC electrodes 40 built in each substrate holding unit 29.

(Etching process)
Next, an etching process (step S2) is performed. Specifically, a gas for etching treatment is supplied from the gas supply unit 12 into the chamber 3, and the inside of the chamber 3 is adjusted to a predetermined pressure by the pressure control unit 13. Subsequently, a high frequency voltage is applied from the first high frequency power supply unit 7 to the ICP coil 5. As a result, plasma is generated in the chamber 3.

  Further, when plasma is generated in the chamber 3, an electrostatic adsorption force is generated between the substrate 2 and the substrate holding unit 29, and the substrate 2 is electrostatically adsorbed on the holding surface 31 of each substrate holding unit 29. The lower surface of the substrate 2 is directly disposed on the holding surface 31 without the tray 15 interposed. Therefore, the substrate 2 is held with high adhesion to the holding surface 31. Thereafter, the cooling gas is supplied at a predetermined pressure from the cooling gas supply unit 45 through the cooling gas supply port 44 into the space existing between the holding surface 31 of each substrate holding unit 29 and the lower surface of the substrate 2. The space is filled with cooling gas. A bias voltage is applied to the metal block 24 of the substrate stage 9 by the second high-frequency power supply unit 56 in a state where the cooling gas is sufficiently filled (maintained at a predetermined pressure), and is generated in the chamber 3. Plasma is drawn toward the substrate stage 9 side. Thereby, the etching process with respect to the board | substrate 2 is performed and the PSS process with respect to the surface of the board | substrate 2 is implemented. Since four substrates 2 can be placed on the substrate stage 9 with one tray 15, batch processing is possible.

  During the etching process, in addition to cooling with the cooling gas, the cooling unit 59 circulates the refrigerant in the refrigerant flow path 60 to cool the metal block 24, thereby the substrate 2 held on the stage upper part 23 and the holding surface 31. Is cooled. Therefore, the temperature of the substrate 2 is reliably controlled in the etching process. When a predetermined processing time elapses, the application of the bias voltage to the metal block 24 of the substrate stage 9 by the second high-frequency power supply unit 56 is stopped, and the supply of the etching process gas is stopped to perform the etching process on the substrate 2. Complete. Thereafter, the application of the DC voltage (drive voltage) to the ESC electrode 40 by the ESC drive power supply unit 41 and the supply of the cooling gas from the cooling gas supply unit 45 are stopped.

  Here, the state of the substrate 2 and the tray 15 immediately after such an etching process is shown in the explanatory diagrams of FIGS. 7A and 7B. As shown in FIG. 7A, in the state where the tray 15 is placed on the tray support portion 28 and the substrate 2 is held on each substrate holding portion 29, the upper surface of the substrate support portion 21 of the tray 15 is displayed. A gap S is provided between 21 a and the lower surface of the edge 2 a of the substrate 2 so as not to contact each other. When the etching process is performed in such a state, the lower surface of the edge 2a of the substrate 2 or the vicinity thereof (part A), the substrate support portion 21 of the tray 15 hidden by the edge 2a of the substrate 2 is covered. On the upper surface 21a and its vicinity (part B), deposits (deposition (deposits)), which are by-products generated during the etching process, are likely to adhere. In the figure, reference numeral 91 is a generated plasma, 92 is a sheath, and 93 is an attached deposit.

  In particular, in the form of transporting while supporting a plurality of substrates 2 using the tray 15, it is necessary to support the edge 2 a of the substrate 2 on the substrate support portion 21 of the tray 15. 29, the edge 2a of the substrate 2 protrudes beyond the outer peripheral end of the substrate holding portion 29. Further, the etching process is performed in a state where there is a gap S between the edge 2 a of the substrate 2 and the substrate support portion 21 of the tray 15. Therefore, a depot 93 that is a by-product of the etching process is formed on the lower surface of the edge 2a of the substrate 2 or the substrate support part 21 of the tray 15 which is a part where the generated plasma is relatively difficult to enter during the etching process. Will stick and become easy to remain. The process of removing the deposit 93 attached between the substrate 2 and the tray 15 in this way is a cleaning process described later.

(Tray height change process)
The tray 15 after the completion of the etching process is placed so as to be in contact with the tray support portion 28 as shown in FIG. When the cleaning process is performed with the tray 15 placed on the tray support 28, the gap S is formed, so that most of the deposits removed by the cleaning process reattach to the side surface 26. The re-deposited deposit is deposited every time the process is repeated. In some cases, the deposit deposited on the side surface 26 wraps around the upper surface of the substrate holder 29. In such a case, a gap is generated between the substrate 2 and the substrate holding part 29, and the He gas supplied as a cooling gas leaks between the substrate 2 and the substrate holding part 29, so that the He gas is supplied. The cooling gas supply unit 45 to be controlled reaches the control limit and may affect the shape of the PSS processing on the surface of the substrate 2 (particularly, the peripheral portion of the substrate 2). In addition, reliable holding of the substrate 2 by the substrate holding unit 29 is hindered, and contamination may occur due to contact between the substrate 2 and the deposit. Therefore, in order to suppress deposition of deposits on the side surface 26, the position (height) of the tray 15 is raised to a position where the substrate 2 is lifted from the substrate holding portion 29, and the gap S is eliminated. Specifically, after the etching process is completed and the application of the bias voltage, the supply of the gas for the etching process, the application of the DC voltage (drive voltage) to the ESC electrode 40 and the supply of the cooling gas are stopped, the drive mechanism 17 raises each tray push-up rod 18 (tray height changing process). As shown in FIG. 8B, when the tray push-up rod 18 is raised, the lower surface 15c of the tray 15 is pushed up at its upper end, and the substrate support portion 21 of the tray 15 and the lower surface of the edge portion 2a of the substrate 2 come into contact with each other. Thus, each substrate 2 is pushed up while being supported by the tray 15, and is lifted (separated) from the holding surface 31 of the substrate holding portion 29. At this time, the gap S formed between the edge 2a of the substrate 2 and the substrate support portion 21 of the tray 15 is eliminated. In this manner, the tray 15 is raised to a position where the by-product removed by the second plasma processing step is prevented from adhering to the substrate holding portion 29.

This tray height changing process is preferably performed during the static elimination process for reducing the residual electrostatic attraction force. After the etching process, even after the application of the DC voltage to the ESC electrode 40 is stopped, the substrate 2 and the holding surface 31 of the substrate holding part 29 are in close contact with each other by the residual electrostatic attraction force, and they can be easily separated. I can't. For this reason, the above-described tray height changing process is performed while performing the charge removal process in which the plasma for charge removal is generated. Specifically, the gas supply unit 12 enters the chamber 3 with a different type of static elimination gas (such as an inert gas such as Ar or He or a gas such as O ₂ that does not easily contribute to etching) from the cleaning gas. ) And plasma is generated in the chamber 3 to reduce the electrostatic adsorption force remaining between the substrate 2 and the substrate holder 29. During this time, the residual electrostatic attraction force between the substrate 2 and the holding surface 31 is neutralized, and the tray height changing process can be executed smoothly.

(Cleaning process)
After the tray height changing process, a cleaning process is performed (step S3). Specifically, a cleaning gas of a different type from the etching gas is supplied from the gas supply unit 12 into the chamber 3, and the inside of the chamber 3 is adjusted to a predetermined pressure by the pressure control unit 13. Subsequently, a high frequency voltage is applied from the first high frequency power supply unit 7 to the ICP coil 5 to generate plasma in the chamber 3. This plasma removes the edge 2a of the substrate 2, the substrate supporting portion 21 of the tray 15, and the deposit attached to the vicinity thereof.

  In this cleaning process, the pressure in the chamber 3 is adjusted to a pressure higher than the pressure in the etching process. Thus, in the cleaning process, by setting the space in the chamber 3 to a high pressure, the isotropic characteristics of the generated plasma can be enhanced, and the deposited deposit can be effectively removed.

  Further, the gap S between the lower surface of the edge portion 2a and the substrate support portion 21 is eliminated by the tray height changing process before the cleaning process. As described above, according to the cleaning process without the gap S, it is possible to suppress the reattachment of the deposit to the side surface 26 as compared with the cleaning process with the gap S present.

  Thereafter, when a predetermined time elapses, the supply of the cleaning process gas is stopped, and the cleaning process for the substrate 2 and the tray 15 is completed.

(Tray unloading process)
Subsequently, a tray unloading process for unloading each substrate 2 together with the tray 15 from the chamber 3 is performed (step S4). Specifically, each tray push-up rod 18 is further raised to the push-up position by the drive mechanism 17, and the tray 15 is positioned at the height (conveyance height) shown in FIGS. 9 (A) and 9 (B). Thereafter, the gate valve 3 a is opened, and the hand portion 81 of the transport mechanism is inserted into the chamber 3. Thereafter, as shown in FIGS. 9B and 9C, the tray 15 in which the substrate 2 is accommodated in each of the four substrate accommodation holes 19 is transferred from the tray push-up rod 18 to the hand portion 81. Thus, the substrate 2 supported by the tray 15 is carried out through the gate valve 3a.

  As described above, according to the cleaning processing method for the substrate 2 of the first embodiment, the etching processing for the substrate 2 is performed in a state where the edge 2a of the substrate 2 and the substrate support portion 21 of the tray 15 are spaced apart from each other. After the etching process, the tray height changing process is performed and then the cleaning process is performed, so that the sub-surface adhered to the edge 2a of the substrate 2 and the substrate support part 21 of the tray 15 during the etching process. The product depot can be effectively removed using the generated plasma. Therefore, when the plurality of substrates 2 are subsequently unloaded from the chamber 3 while being accommodated in the tray 15, it is possible to prevent the deposits from dropping due to contact between the tray 15 and the substrate 2. In addition, a tray height changing process is performed prior to the cleaning process, and the cleaning process is performed in a state in which the gap S between the lower surface of the edge 2a and the substrate support part 21 is eliminated, so that the deposit is deposited on the side surface 26. It is possible to prevent the deposit deposited on the side surface 26 from entering the upper surface of the substrate holding portion 29. Therefore, it is possible to prevent the He gas from leaking from the gap between the substrate 2 and the substrate support portion 29 and cause the cooling gas supply unit 45 to become uncontrollable, and to reduce the influence on the shape of the PSS processing on the surface of the substrate 2. In addition, the substrate 2 can be reliably held by the substrate holder 29.

  Therefore, it is not necessary to frequently wipe off the deposit attached to the side surface 26, and troubles such as the occurrence of contamination when the deposit is dropped, deposited, or wraps around the substrate holding portion 29 and the next processing is performed. Since generation | occurrence | production can be avoided, the quality of the product in the etching processing method of the board | substrate 2 can be improved, and a maintenance cycle can be extended.

  Moreover, in the etching method of this Embodiment 1, when processing using a sapphire substrate as the board | substrate 2, the operating conditions of each process can be set as follows. These operating conditions are stored in advance in the operating condition storage unit 77 of the control unit 70. These operating conditions are merely examples, and can be set to optimum conditions depending on the type of substrate to be processed, the processing content, and the like.

Etching process:
Process gas type and flow rate: BCl ₃ , 200cc
Processing pressure: 0.6Pa
ICP coil applied power: 1400W
Bias: 1600W
Applied voltage to ESC electrode: 2.0 kV
Cooling gas pressure: 2.0 kPa
Processing time: 10min

Cleaning process:
Process gas type / flow rate: O ₂ , 200 cc / CF ₄ , 200 cc
Processing pressure: 8.0 Pa
ICP coil applied power: 1800W
Bias: 0W
Applied voltage to ESC electrode: 0 kV
Cooling gas pressure: 0 kPa
Processing time: 2min

  Note that the height of the tray 15 during the cleaning process may be the conveyance height. In this case, since the tray 15 can be unloaded without changing the height when it is unloaded, the efficiency of the tray unloading process can be improved.

In the first embodiment, the case where the tray height changing process is performed before the start of the cleaning process has been described. However, the tray height changing process may be performed during the cleaning process. The plasma at the time of the cleaning process is also advantageous in that it eliminates the need for the above-described neutralization process because it has a neutralization effect.
In this case, it is preferable to shorten the time from the start of the cleaning process to the start of the tray height changing process, and it is more preferable that the differential pressure between the cooling gas and the pressure inside the chamber is zero.

(Embodiment 2)
Next, a plasma processing method according to Embodiment 2 of the present invention will be described. In the first embodiment, the cleaning process is performed in a state where the gap S between the edge 2a of the substrate 2 and the substrate support portion 21 of the tray 15 is eliminated as a position for suppressing the deposition of the deposit on the substrate holding portion 29. In the second embodiment, the cleaning process is performed in a state where the gap S between the edge 2a of the substrate 2 and the substrate support portion 21 of the tray 15 is reduced. About the apparatus, since the same apparatus as Embodiment 1 is used, the same referential mark is attached | subjected to the same structural member and the description is abbreviate | omitted. The following description will focus on the differences between the second embodiment and the first embodiment.

  As shown in FIG. 10A, the tray 15 after the etching process is placed so as to be in contact with the tray support portion 28. As in the first embodiment, gas supply, pressure adjustment, and application of direct current to the ESC electrode 40 are stopped. Thereafter, as shown in FIG. 10B, the gap 15 between the edge 2 a of the substrate 2 and the substrate support portion 21 is reduced by pushing up the tray 15 with the tray push-up rod 18. In this case, the dimension d2 of the gap S formed between the lower surface of the edge 2a and the substrate support 21 is smaller than the dimension d1 of the gap S when the tray 15 is not pushed up. Thus, after raising the tray 15 to a position where adhesion of deposition is suppressed so that the gap S between the edge portion 2a of the substrate 2 and the substrate support portion 21 is reduced, the second high-frequency power supply unit 56 is used. The cleaning process is started by generating plasma in the chamber 3 without applying the bias voltage.

(Tray unloading process)
When the cleaning process is finished, a tray unloading process for unloading each substrate 2 from the chamber 3 together with the tray 15 is performed (step S4). By further raising each tray push-up rod 18, the substrate support portion 21 of the tray 15 and the lower surface of the edge portion 2 a of the substrate 2 come into contact with each other, and each substrate 2 is pushed up in a state of being supported by the tray 15. And lifts from the holding surface 31 of the substrate holding part 29. The tray push-up rod 18 is raised to the push-up position (tray 15 is transported) as it is. Also in this case, the tray carry-out process is performed while performing the static elimination process for reducing the residual electrostatic attraction force between the substrate 2 and the substrate holding unit 29 as in the first embodiment.

  Thereafter, as in the first embodiment, the gate valve 3a is opened, the hand portion 81 of the transport mechanism is inserted into the chamber 3, and the trays in the state where the substrates 2 are accommodated in the four substrate accommodating holes 19, respectively. 15 is transferred from the tray push-up rod 18 to the hand portion 81, and the substrate 2 supported by the tray 15 is carried out through the gate valve 3a.

  As described above, in the second embodiment, the cleaning process is performed in a state where the gap S between the lower surface of the edge part 2a and the substrate support part 21 is reduced, so that the edge part 2a and the substrate are etched during the etching process. The depot can be effectively removed using plasma while suppressing the deposition of the by-product adhering to the support portion 21 from reattaching and depositing on the side surface 26. Therefore, the influence on the shape of the PSS processing on the surface of the substrate 2 due to the leak of He gas can be reduced, and the substrate 2 can be surely held by the substrate holding portion 29 and the occurrence of the contamination can be suppressed. As a result, the maintenance cycle of the dry etching apparatus 1 can be extended. Further, in the second embodiment, since the cleaning process is performed in a state where the gap S exists, it adheres to the edge portion 2a of the substrate 2 and its lower surface, compared to the first embodiment in which the cleaning process is performed without the gap S. The deposited depot can be removed sufficiently.

  In the second embodiment, the cleaning process is performed by reducing the gap S before the start of the cleaning process. However, the tray height changing process is further performed in the middle of the cleaning process, as in the first embodiment. The gap S may be eliminated. As described above, by limiting the state in which the gap S is reduced to the early stage of the cleaning process, it is possible to significantly reduce deposition of deposits on the side surface 26 of the substrate holding portion 29.

  Furthermore, although the case where the tray height changing process is performed before the start of the cleaning process has been described in the second embodiment, the tray height changing process may be performed during the cleaning process. In this case, it is preferable to shorten the time from the start of the cleaning process to the start of the tray height changing process, and it is more preferable that the differential pressure between the cooling gas and the pressure inside the chamber is zero.

  Furthermore, in the second embodiment, the tray unloading process is performed after the cleaning process. However, at the final stage of the cleaning process, the first half of the tray unloading process (the tray 2 is lifted to remove the substrate 2 from the holding surface 31 of the substrate holding unit 29). May be raised). This is also advantageous in that it is not necessary to perform the above-described charge removal process.

  In addition, this invention is not limited to the above-mentioned structure, It can implement in another various aspect. For example, instead of the sapphire substrate, the etching method of the above-described embodiment can be applied to a silicon substrate.

  Furthermore, the etching method of the above-described embodiment can be applied to a quadrangular substrate instead of the disc-shaped substrate. An example of such a rectangular substrate is a solar panel substrate. In a solar panel substrate, in order to efficiently absorb sunlight, a minute concavo-convex structure is formed on the surface of the substrate by etching treatment or surface texture processing, and in that the concavo-convex structure is formed by etching treatment, Common. In addition, such solar panel substrates are often formed of silicon-based materials, and the conveyance of the substrates using a tray is employed.

  Further, in the above-described configuration, the example in which the entire periphery of the edge portion 2a of the substrate 2 is supported by the substrate support portion 21 formed over the entire periphery of the inner wall of the substrate accommodation hole 19 of the tray 15 has been described. However, a configuration in which the substrate support portion 21 is formed on a part of the inner wall of the substrate accommodation hole 19 and the edge portion 2a of the substrate 2 is supported on a part of the outer periphery thereof may be employed.

  In addition, after the etching processing method of the above-described embodiment is continuously performed on a plurality of trays 15, a cleaning process is performed in a state where the tray 15 is not placed in the chamber 3. You may make it remove the deposit which has adhered.

  Furthermore, in the above embodiment, the case where the tray height changing process is performed before the start of the cleaning process has been described. However, the tray height changing process may be performed during the cleaning process. In this case, it is preferable to shorten the time from the start of the cleaning process to the start of the tray height changing process, and it is more preferable that the differential pressure between the cooling gas and the pressure inside the chamber is zero.

In the first and second embodiments, the case where BCl3 is used as an etching process (first plasma process) gas is described as an example. However, as the etching process gas, a BCl3-based gas such as BCl3 is used. ₃ / Cl ₂ / Ar, BCl ₃ / Cl ₂ , Bcl ₃ / Ar, or the like may be used. In the first and second embodiments, the case where a mixed gas of O ₂ / CF ₄ is used as an example of a cleaning process (second plasma process) gas has been described as an example. May be a mixed gas of O ₂ / fluorine-based gas, for example, O ₂ / SF ₆ , O ₂ / CHF ₃ , O ₂ / NF _{3 and the} like.
It is to be noted that, by appropriately combining arbitrary embodiments of the various embodiments described above, the effects possessed by them can be produced.

  INDUSTRIAL APPLICABILITY The present invention is useful for a method for performing plasma processing on a plurality of substrates that are transported in a state of being accommodated in a tray. It can be applied to a method in which surface texture processing is performed by etching.

DESCRIPTION OF SYMBOLS 1 Dry etching apparatus 2 Substrate 2a Edge 3 Chamber 3a Gate valve 4 Top plate 5 ICP coil 6 Top plate cover part 7 1st high frequency power supply part 9 Substrate stage 10 Coil cover part 12 Gas supply part 13 Pressure control part 15 Tray 15a Tray body 17 Drive mechanism 18 Tray push-up rod 19 Substrate receiving hole 21 Substrate support portion 23 Upper stage 24 Metal block 25 Insulator 26 Side surface 28 Tray support portion 29 Substrate holding portion 30 Guide ring 31 Holding surface 40 ESC electrode 41 ESC drive power supply portion 45 Cooling gas supply unit 56 Second high frequency power supply unit 59 Cooling unit 70 Control unit 71 Operation / input unit 72 Display unit 73 Transfer processing unit 74 Etching processing unit 75 Cleaning processing unit 76 Static elimination processing unit 77 Operating condition storage unit

Claims (11)

A plurality of substrate accommodation holes for accommodating the substrate are provided, and a tray having a substrate support portion protruding from the inner wall of the substrate accommodation hole is used, and the edge portion is supported by the substrate support portion and accommodated in the substrate accommodation hole. A substrate carrying-in step of carrying a plurality of substrates in a state of being brought into the chamber;
In a chamber, with respect to a substrate stage having a tray support portion and a plurality of substrate holding portions protruding upward from the tray support portion, a tray is placed on the tray support portion and a substrate is placed on each substrate holding portion. A substrate mounting step in which a gap is formed between the edge of the substrate protruding from the edge of the substrate holding portion and the substrate support portion,
A first plasma processing step of supplying a processing gas into the chamber and adjusting a pressure in the chamber to perform plasma processing on each substrate in a state where the tray and each substrate are placed on the substrate stage; ,
A process gas is supplied into the chamber and a plasma process is performed by adjusting a pressure in the chamber, and a by-product attached to the edge of the substrate and the substrate support is removed by performing the first plasma process. Two plasma treatment steps;
A substrate unloading step of unloading each substrate from the chamber together with the tray in a state where the edge of the substrate is supported by the substrate support portion after the second plasma processing step is completed;
In the second plasma processing step, a plasma processing method for a substrate, wherein the plasma processing is performed in a state where the tray is raised to a position where the by-product removed by the second plasma processing step is prevented from adhering to the substrate holding portion. .   When the second plasma processing step is performed after the first plasma processing step is completed, the processing gas is switched to a different type of processing gas from the processing gas in the first plasma processing step, and the pressure is higher than the pressure in the first plasma processing step. The substrate plasma processing method according to claim 1, wherein the second plasma processing step is performed. In the first plasma processing step, each substrate is attracted and held on the substrate holding portion by electrostatic attraction, and plasma processing is performed while cooling with a cooling gas supplied at a predetermined pressure between the substrate and the substrate holding portion. ,
The electrostatic chucking is performed by switching to a driving voltage lower than the driving voltage for electrostatic chucking in the first plasma processing step when the second plasma processing step is performed after the first plasma processing step is completed. The plasma processing method of the board | substrate of description.   The substrate plasma processing method according to claim 3, wherein when performing the second plasma processing step, the pressure is switched to a pressure lower than the pressure of the cooling gas in the first plasma processing step.   5. The plasma processing method for a substrate according to claim 4, wherein the differential pressure between the electrostatic adsorption driving voltage when performing the second plasma processing step, the pressure inside the chamber and the cooling gas in the second plasma processing step is zero. .   The substrate plasma processing method according to claim 3, wherein a sapphire substrate is used as the substrate, and in the first plasma processing step, a process of forming a minute uneven structure on the surface of the sapphire substrate is performed as plasma processing. The substrate plasma processing method according to claim 6, wherein a gas mainly composed of BCl ₃ is used as a processing gas in the first plasma processing step, and a mixed gas of O ₂ / fluorine gas is used as a processing gas in the second plasma processing step.   2. The substrate according to claim 1, wherein the position at which the adhesion of the by-product removed by the second plasma treatment step is suppressed to a height at which the edge of the substrate is supported by the substrate support portion of the tray. Plasma processing method.   Prior to the second plasma treatment step, a discharge plasma is generated, and the tray is raised to a height that supports the edge of the substrate while performing a discharge treatment that reduces the residual electrostatic attraction between the substrate and the substrate holding portion. The substrate plasma processing method according to claim 8, wherein the substrate is raised.   The position at which the by-product removed by the second plasma processing step is prevented from adhering to the substrate holding portion is a height at which the substrate support portion of the tray maintains a gap without contacting the edge of the substrate. Item 2. The plasma processing method for a substrate according to Item 1.   After completion of the second plasma processing step, discharge plasma is generated, and the substrate is lifted from the holding surface of the substrate holding portion while performing discharging treatment to reduce the residual electrostatic attraction between the substrate and the substrate holding portion. The method for plasma processing a substrate according to claim 10.

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