Plasma processing apparatus and plasma processing method

Abstract

To improve accuracy of temperature measurement processing of a wafer being an object to be processed, and to improve throughput of the temperature measurement processing.SOLUTION: An electrostatic chuck 30 comprises: an insulation layer 31; and a projection part 31a that is provided along an outer periphery of the insulation layer 31, and projects from an upper surface of the insulation layer 31. A through-hole 25 penetrates through the insulation layer 31 and a sample stage 20. A support rod 40 is provided within the through-hole 25, and a temperature sensor 41 is attached to the support rod 40 at a position far from an upper end of the support rod 40. The support rod 40 and the temperature sensor 41 are positioned within the through-hole 25 to be far from a wafer WF1 when the wafer WF1 is adsorbed to the projection part 31a to be far from the upper surface of the insulation layer 31. Gas is supplied from a gas supply pipe 24 to a space 50 between the upper surface of the insulation layer 31 surrounded by the projection part 31a and the wafer WF1, and the temperature sensor 41 measures temperature of the gas flowed from the space 50 into the through-hole 25.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a plasma processing apparatus and a plasma processing method, and more particularly to a plasma processing apparatus having a temperature sensor and a plasma processing method carried out using the plasma processing apparatus. [Background technology]

[0002] In semiconductor integrated circuits, miniaturization and three-dimensionalization of integrated circuits are being promoted to meet market demands such as improved circuit performance and increased memory capacity. As integrated circuits are further miniaturized, it is required to stably form circuit patterns with higher aspect ratios. Therefore, in the semiconductor manufacturing process, cleaning and removal technologies using dry etching are required to replace conventional cleaning and removal technologies using wet etching.

[0003] As one of the above-mentioned dry etching processes, processing techniques for forming patterns with controllability at the atomic layer level are being developed. As such a processing technique, a technique called ALE (Atomic Level Etching) method has been developed.

[0004] For example, Patent Document 1 discloses a technique for etching an object to be treated at the atomic layer level by supplying microwaves to the object while the object is adsorbed with an etchant gas, and generating a low-electron-temperature plasma of an inert gas such as a rare gas (Ar gas). In the above etching process, the constituent atoms of the object to be treated that are bonded to the etchant gas are separated from the object to be treated by heat generated by activation of the rare gas, without breaking the bond.

[0005] Patent Document 2 discloses an adsorption / desorption type etching apparatus using infrared light irradiation. This etching apparatus includes a vacuum vessel capable of reducing pressure, a radical source for generating active species, a substrate stage for placing a substrate, a lamp unit for heating the substrate, and a flow path for flowing the active species downward. The radical source is disposed inside a processing chamber of the vacuum vessel. The substrate stage is disposed below the radical source inside the processing chamber. The lamp unit is disposed between the radical source and the substrate stage inside the processing chamber. The flow path is disposed on the outer periphery and in the center of the lamp unit.

[0006] Moreover, Patent Document 2 discloses a plasma processing apparatus including the above-mentioned etching apparatus, a plurality of gas supply means for supplying processing gas to the central portion and the outer circumferential side of the radical source, and a control unit for adjusting the gas supplied from the plurality of gas supply means.

[0007] In order to etch an object to be processed at the atomic layer level by the ALE method, it is important to control the temperature of the object to be processed (wafer). For this reason, in Patent Document 1, a temperature sensor is provided inside the sample stage.

[0008] In addition, in Patent Document 2, a lamp that emits infrared light is used to heat the surface of the substrate. By controlling the voltage applied to this lamp, the substrate can be heated in a relatively short time. In addition, when the substrate is heated, relatively high-energy charged particles are not incident on the substrate surface, so that the etchant gas can be adsorbed on the substrate surface and the surface layer can be detached without damaging the substrate surface.

[0009] In addition, in Patent Document 3, various films are formed on the surface of a substrate depending on the processing steps that have been passed through. Even if the same processing steps have been passed through, there is a problem that the reflectance or heat capacity of the surface varies slightly for each substrate. To solve this problem, the sample stage on which the substrate is placed is equipped with a temperature measurement unit. When the irradiation unit irradiates the sample placed on the sample stage with infrared light, the intensity of the infrared light irradiated from the irradiation unit to the sample is controlled based on the temperature measured by the temperature measurement unit. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] JP 2019-161157 A [Patent Document 2] JP 2016-178257 A [Patent Document 3] International Publication No. 2013 / 168509 Summary of the Invention [Problem to be solved by the invention]

[0011] In order to control etching at the atomic layer level, it is necessary to minimize the damage caused by plasma to the surface of the workpiece, and to increase the accuracy of controlling the amount of etching. As a method for solving these problems, as described in Patent Documents 1 and 2, there is a method in which an etchant gas is chemically adsorbed onto the surface of the workpiece, and thermal energy is applied to this to separate the surface layer of the workpiece.

[0012] However, the method described in Patent Document 1 uses a rare gas with a low electronic temperature activated by microwaves to heat the surface of the workpiece, which has the problem that it is not possible to shorten the heating time of the workpiece and increase the throughput of the heat treatment.

[0013] In addition, in Patent Document 2, a temperature sensor placed in a hole inside the base material of the sample stage is used to detect the temperature of the substrate placed on the sample stage while IR heating the substrate. In this case, there is a problem that the responsiveness of the temperature measurement is impaired.

[0014] Similarly, in Patent Document 3, in a configuration in which a temperature measurement unit is provided on the sample stage, an electrostatic chuck is interposed between the substrate and the temperature measurement unit, making it difficult for the temperature measurement unit to detect the temperature with high accuracy.

[0015] Thus, in the conventional technology, when the substrate is heated in a short time, the accuracy of the detected substrate temperature is reduced, resulting in a decrease in the yield of the temperature measurement process. Also, when the substrate temperature is detected with high accuracy, a long time is required, resulting in a decrease in the throughput of the temperature measurement process.

[0016] The main object of the present application is to improve the accuracy of a temperature measurement process for a wafer (substrate) that is a processing object, and to improve the throughput of the temperature measurement process. Other objects and novel features will become apparent from the description of this specification and the accompanying drawings. [Means for solving the problem]

[0017] In one embodiment, the plasma processing apparatus includes a vacuum vessel, a processing chamber provided in the vacuum vessel, a sample stage provided in the processing chamber, an insulating layer provided on the sample stage, a protrusion provided along the outer periphery of the insulating layer and protruding from the upper surface of the insulating layer, and an electrostatic chuck including a plurality of electrodes provided inside the insulating layer, a gas supply pipe for supplying a first gas from a gas supply source provided outside the vacuum vessel to the upper surface of the insulating layer, a through hole penetrating the insulating layer and the sample stage so as to reach the upper surface of the insulating layer, a support rod provided inside the through hole, and a moving mechanism for moving the support rod in a vertical direction. Here, a temperature sensor is attached to the support rod at a position away from the upper end of the support rod. Furthermore, when the wafer is adsorbed onto the protrusion so as to move away from the upper surface of the insulating layer, the support rod and the temperature sensor are positioned inside the through hole so as to move away from the wafer, the first gas is supplied from the gas supply pipe to a first space between the upper surface of the insulating layer surrounded by the protrusion and the wafer, and the temperature sensor measures the temperature of the first gas that flows from the first space into the inside of the through hole.

[0018] In one embodiment, a plasma processing method is performed on a wafer using a plasma processing apparatus including a vacuum vessel, a processing chamber provided inside the vacuum vessel, a sample stage provided in the processing chamber, an insulating layer provided on an upper portion of the sample stage, a protrusion provided along the outer periphery of the insulating layer and protruding from an upper surface of the insulating layer, and an electrostatic chuck including a plurality of electrodes provided inside the insulating layer, an electrode power supply electrically connected to the plurality of electrodes, a gas supply pipe for supplying a first gas from a gas supply source provided outside the vacuum vessel to the upper surface of the insulating layer, a through hole penetrating the insulating layer and the sample stage to reach the upper surface of the insulating layer, a support rod provided inside the through hole, and a moving mechanism for enabling the support rod to move in an up and down direction. The plasma processing method further includes the steps of: (a) placing the wafer on an upper end of a support rod with the upper end of the support rod positioned above the protrusion; (b) after step (a), moving the support rod downward using the moving mechanism to place the wafer on the protrusion and position the support rod inside the through hole so as to move it away from the wafer; (c) after step (b), applying a voltage from the electrode power supply to the multiple electrodes to adsorb the wafer to the protrusion so as to move it away from the upper surface of the insulating layer; (d) after step (c), supplying the first gas from the gas supply pipe to a first space between the wafer and the upper surface of the insulating layer surrounded by the protrusion, and flowing the first gas from the first space into the inside of the through hole; and (e) after step (d), measuring a temperature of the first gas inside the through hole. Here, a temperature sensor is attached to the support rod at a position away from the upper end of the support rod, and the step (e) is carried out using the temperature sensor. Effect of the Invention

[0019] According to one embodiment, it is possible to improve the accuracy of the temperature measurement process of the substrate, which is the object to be processed, and to improve the throughput of the temperature measurement process. [Brief description of the drawings]

[0020] [Figure 1] 1 is a schematic diagram showing an overview of a plasma processing apparatus in a first embodiment. [Diagram 2] 2 is a schematic diagram showing the periphery of the sample stage in the first embodiment. FIG. [Diagram 3] 2 is a schematic diagram showing the periphery of the sample stage in the first embodiment. FIG. [Figure 4] 2 is an enlarged schematic diagram of the periphery of a temperature sensor in the first embodiment. FIG. [Diagram 5] 2 is a schematic diagram of a wafer with a thermocouple in the first embodiment. FIG. [Figure 6] 4 is an example of a database showing a correspondence relationship between a temperature measured by a temperature sensor and a temperature measured by a thermocouple-attached wafer in the first embodiment. [Figure 7] FIG. 4 is a block diagram showing a method for correcting the heating temperature by the lamp in the first embodiment. [Figure 8] 3 is a flowchart showing a plasma processing method in the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, the embodiments will be described in detail with reference to the drawings. In all the drawings for explaining the embodiments, the same reference numerals are used for the members having the same functions, and the repeated explanations are omitted. In the following embodiments, the explanations of the same or similar parts will not be repeated as a rule unless it is particularly necessary.

[0022] (Embodiment 1) <Configuration of Plasma Processing Apparatus> An overview of a plasma processing apparatus 1 according to the first embodiment will be described below with reference to FIG.

[0023] The plasma processing apparatus 1 includes a cylindrical vacuum vessel 2, a plasma generation chamber 3 and a processing chamber 4 provided inside the vacuum vessel 2, a sample stage 20 provided inside the processing chamber 4, an electrostatic chuck 30 provided on top of the sample stage 20, an overall control unit C0, a lamp control unit C1, an electrode control unit C2, a refrigerant control unit C3, a gas flow rate control unit C4, and a sensor control unit C5.

[0024] A disk-shaped plate 5 is provided above the sample stage 20. The plate 5 is made of a dielectric material such as quartz. The plate 5 has a plurality of holes 6. The space above the plate 5 serves as a plasma generation chamber 3, and the space below the plate 5 serves as a processing chamber 4. A wafer (substrate) WF1, which is an object to be processed, is placed on an electrostatic chuck 30.

[0025] The plasma processing apparatus 1 also includes a waveguide 7, a high-frequency power supply 8, a gas introduction pipe 9, and a gas supply device 10. The waveguide 7 is disposed at the top of the plasma generation chamber 3, and the high-frequency power supply 8 is provided at the end of the waveguide 7. The high-frequency power supply 8 can oscillate and output a microwave electric field. The waveguide 7 is a conduit through which the microwave electric field propagates, and the microwave electric field is supplied to the inside of the plasma generation chamber 3 via the waveguide 7. A processing gas is supplied from the gas supply device 10 to the inside of the plasma generation chamber 3 via the gas introduction pipe 9.

[0026] The overall control unit C0 is electrically connected to the high frequency power supply 8 and the gas supply device 10. The microwave output from the high frequency power supply 8 and the type and flow rate of the processing gas supplied from the gas supply device 10 are controlled by the overall control unit C0.

[0027] When a microwave electric field is generated from the high frequency power supply 8, the microwave electric field propagates inside the waveguide 7 and passes through the plate 5. Atoms or molecules of the processing gas supplied from the gas supply device 10 are excited, ionized, or dissociated, thereby generating plasma inside the plasma generation chamber 3. The processing gas (radicals) excited by the plasma generated in the plasma generation chamber 3 flow out from the plasma generation chamber 3 to the processing chamber 4 through the multiple holes 6. Some of these radicals are adsorbed onto the surface of the wafer WF1, thereby forming a reaction layer on the surface of the wafer WF1.

[0028] The plasma processing apparatus 1 also includes lamps 11 for heating the wafer WF1, a protective plate 12 that covers the periphery of the lamps 11, and a lamp power supply 13 for applying a voltage to the lamps 11. The lamps 11 are provided above the processing chamber 4 and outside the vacuum vessel 2. The lamps 11 are also provided in a ring shape outside the vacuum vessel 2 so as to surround the vacuum vessel 2. The lamp power supply 13 is electrically connected to the lamps 11. A quartz window 14 is formed in a part of the vacuum vessel 2 so as to allow infrared rays generated by the lamps 11 to pass through.

[0029] When the wafer WF1 is placed on the sample stage 20 via the electrostatic chuck 30, the wafer WF1 can be heated by such lamps 11. In addition, by adjusting the voltage applied from the lamp power supply 13 to the lamps 11, the heating temperature of the wafer WF1 can be controlled.

[0030] The lamp control unit C1 is electrically connected to the lamp power supply 13 and controls the operation of the lamp power supply 13. For example, the magnitude of the voltage applied from the lamp power supply 13 to the lamp 11 and the ON / OFF of the applied voltage are controlled by the lamp control unit C1.

[0031] The plasma processing apparatus 1 includes an opening 15 provided in the vacuum vessel 2, and a vacuum exhaust device 16 for evacuating the inside of the vacuum vessel 2. The vacuum exhaust device 16 evacuates the inside of the vacuum vessel 2 through the opening 15, and maintains the inside of the vacuum vessel 2 at a predetermined pressure.

[0032] 2 and 3 are schematic diagrams showing the periphery of the sample stage 20. Fig. 4 is a schematic enlarged view of the periphery of the temperature sensor 41. Fig. 2 shows a state before the wafer WF1 is placed on the electrostatic chuck 30, and Figs. 3 and 4 show a state after the wafer WF1 is placed on the electrostatic chuck 30.

[0033] 2 and 3, a flow path 21 for a coolant to flow is provided inside the sample stage 20. A coolant supply pipe 22 for supplying the coolant and a coolant discharge pipe 23 for discharging the coolant are connected to the flow path 21. The coolant flows through the flow path 21, thereby cooling the sample stage 20 and adjusting the temperature of the wafer WF1 to a value within a range appropriate for starting the plasma processing. The material constituting the sample stage 20 is a low-temperature toughness material, such as aluminum or an aluminum alloy.

[0034] The coolant control unit C3 is connected to the coolant supply pipe 22 and the coolant discharge pipe 23 outside the processing chamber 4. The flow rate and temperature of the coolant flowing from the coolant supply pipe 22 to the flow path 21 are adjusted by the coolant control unit C3.

[0035] Although not shown, a high frequency power supply is electrically connected via an impedance matching device to the sample stage 20. During plasma processing of the wafer WF1, high frequency power is supplied from the high frequency power supply to the sample stage 20 in order to form an electric field for attracting charged particles in the plasma on the upper surface of the wafer WF1.

[0036] Further, an electrostatic chuck 30 is provided on the upper part of the sample stage 20. The electrostatic chuck 30 includes an insulating layer 31, a protruding portion 31a protruding from the upper surface of the insulating layer 31, and a plurality of electrodes 32 provided inside the insulating layer 31. The material constituting the insulating layer 31 may be an inorganic material such as aluminum oxide, or a resin material such as polyimide. The protruding portion 31a may be made of the same material as the insulating layer 31, or may be made of a different material from the insulating layer 31.

[0037] The protrusion 31a is provided at least along the outer periphery of the insulating layer 31. That is, the protrusion 31a has a cylindrical shape. The protrusion 31a has a shape smaller than the outer periphery of the wafer WF1. Therefore, as shown in FIG. 3, when the wafer WF1 is adsorbed to the protrusion 31a, the wafer WF1 is separated from the upper surface of the insulating layer 31, and a space 50 is formed between the upper surface of the insulating layer 31 surrounded by the protrusion 31a and the wafer WF1. In order to maintain the formation of the space 50, other protrusions (embossments) having the same height as the protrusion 31a and made of the same material as the protrusion 31a may be provided not only on the outer periphery of the insulating layer 31 but also inside the outer periphery of the insulating layer 31.

[0038] A gas supply pipe 24 is provided inside the insulating layer 31 and the sample stage 20, penetrating the insulating layer 31 and the sample stage 20 so as to reach the upper surface of the insulating layer 31. The gas supply pipe 24 is a pipe for supplying gas from a gas supply source provided outside the vacuum vessel 2 to the upper surface of the insulating layer 31. This gas is used to adjust the temperature of the wafer WF1 from the back surface side of the wafer WF1, and is a heat transfer gas, such as helium gas (He gas).

[0039] The gas flow rate control unit C4 is electrically connected to the gas supply pipe 24 outside the processing chamber 4. The flow rate and pressure of the gas flowing from the gas supply pipe 24 to the space 50 are adjusted by the gas flow rate control unit C4.

[0040] A plurality of electrodes 32 are provided inside the insulating layer 31. Here, the plurality of electrodes 32 are a pair of thin-film electrodes. The plurality of electrodes 32 are also electrically connected to the electrode power supply 17. By applying a predetermined voltage from the electrode power supply 17 to the plurality of electrodes 32, an electrostatic force is generated, and this electrostatic force can attract the wafer WF1 to the protruding portion 31a so as to separate it from the upper surface of the insulating layer 31.

[0041] The electrode control unit C2 is electrically connected to the electrode power supply 17, and controls the driving of the electrode power supply 17. For example, the magnitude of the voltage applied from the electrode power supply 17 to the multiple electrodes 32 and the ON / OFF of the applied voltage are controlled by the electrode control unit C2.

[0042] A through hole 25 is provided inside the insulating layer 31 and the sample stage 20, penetrating the insulating layer 31 and the sample stage 20 so as to reach the upper surface of the insulating layer 31. A support rod 40 is provided inside the through hole 25. The lower end of the support rod 40 is connected to a movement mechanism 42 for enabling the support rod 40 to move in the vertical direction. The material constituting the support rod 40 is preferably a non-metallic material with high thermal conductivity, such as silicon carbide.

[0043] Further, a temperature sensor 41 is attached to the support rod 40 at a position away from the upper end of the support rod 40. The temperature sensor 41 is, for example, a resistance temperature detector type temperature sensor. Before the wafer WF1 is attracted to the protruding portion 31a, the wafer WF1 is supported by the upper end of the support rod 40.

[0044] 3 and 4, when the wafer WF1 is sucked to the protruding portion 31a, the support rod 40 and the temperature sensor 41 are located inside the through hole 25 so as to be separated from the wafer WF1. At that time, the inside of the gas supply pipe 24, the space 50, and the inside of the through hole 25 are in a state of communication. Then, the gas is supplied from the gas supply pipe 24 to the space 50, contacts the wafer WF1 in the space 50, and heat is transferred between the back surface of the wafer WF1 and the insulating layer 31. The gas that contacts the wafer WF1 further flows into the through hole 25. The temperature sensor 41 measures the temperature of the gas that flows into the through hole 25 as the temperature of the wafer WF1. Although not shown in detail, the gas that flows into the through hole 25 flows out into the inside of the processing chamber 4 and is exhausted from the opening 15 by the vacuum exhaust device 16.

[0045] The sensor control unit C5 is electrically connected to a temperature sensor 41 outside the processing chamber 4 via a conductor 44, and controls the temperature sensor 41. In addition, the temperature measured by the temperature sensor 41 is calculated by the sensor control unit C5, and the calculated measured temperature is sent to the overall control unit C0.

[0046] Here, when the sample stage 20 is cooled by the coolant flowing through the flow path 21, the heat of the wafer WF1 is transferred to the sample stage 20 side via the gas filling the space 50 and the insulating layer 31. This cools the wafer WF1. At the same time, the temperature of the gas in the space 50 in contact with the wafer WF1 also changes. On the other hand, when the wafer WF1 is heated by the lamps 11, heat is accumulated in the wafer WF1, and the temperature of the wafer WF1 rises. At the same time, the temperature of the gas in the space 50 in contact with the wafer WF1 also changes. The temperature sensor 41 measures the temperature of the gas in the space 50, and measures the temperature of the wafer WF1.

[0047] In addition, a partition wall 43 is provided on the inner wall of the through hole 25. The sample stage 20 is preferably made of a material with a relatively high thermal conductivity so that the temperature of the refrigerant flowing through the flow path 21 is easily reflected. On the other hand, the temperature and radiant heat of the sample stage 20 may affect the temperature measured by the temperature sensor 41. Therefore, in order to isolate the temperature sensor 41 from the sample stage 20, a partition wall 43 is provided on the inner wall of the through hole 25 as a heat insulating material. The partition wall 43 is made of a material with a lower thermal conductivity than the material constituting the sample stage 20, for example, fine ceramics.

[0048] In order to stably support the wafer WF1, it is preferable to provide three or more through holes 25 and three or more support rods 40. The temperature sensor 41 may be provided on at least one of the three or more support rods 40, but may be provided on all or some of the three or more support rods 40. By providing a plurality of temperature sensors 41, the temperature of the wafer WF1 can be measured with higher accuracy by using a means such as calculating an average value of the temperatures measured by the respective temperature sensors 41.

[0049] The overall control unit C0 controls the overall operation of the plasma processing apparatus 1. That is, the overall control unit C0 is electrically connected to the lamp control unit C1, the electrode control unit C2, the refrigerant control unit C3, the gas flow rate control unit C4, and the sensor control unit C5, controls their drive and operation, and is capable of communicating with these units.

[0050] In this application, for ease of understanding, each of the control units C2 to C5 is individually illustrated near the control target related to each of them, but each of the control units C2 to C5 may be integrated into one control unit as part of the overall control unit C0. Therefore, in this application, the operations performed by each of the control units C2 to C5 may be described as being performed by the overall control unit C0, and the overall control unit C0 including each of the control units C2 to C5 may be simply referred to as the "control unit."

[0051] <How to correct the heating temperature using a lamp> In the first embodiment, the gas temperature measured by the temperature sensor 41 is the temperature of the wafer WF1. If it is possible to estimate in advance under what conditions the applied voltage of the lamp power supply 13 should be controlled so that the gas temperature measured by the temperature sensor 41 (the heating temperature of the wafer WF1) becomes a desired temperature when the wafer WF1 is heated by the lamps 11, the throughput of the temperature control process can be improved.

[0052] 5 to 7, a method for correcting the heating temperature by lamp 11 will be described below. In this method, general control unit C0 controls the applied voltage of lamp power supply 13 based on the gas temperature measured by temperature sensor 41 and the pressure of the gas supplied from gas supply pipe 24 to space 50 so that the heating temperature by lamp 11 is corrected to a desired heating temperature.

[0053] First, in order to measure the heating characteristics of the lamps 11, a wafer WF1 and another wafer (substrate) WF2 are prepared as shown in Fig. 5. Temperature sensors 61 such as thermocouples are attached to a plurality of points 60 on the surface of the wafer WF2.

[0054] The part of the temperature sensor 61 that contacts the point 60 serves as the sensor. The temperature sensor 61 has a wiring section for transmitting a signal from the sensor, and a thermometer for displaying temperature information. The wiring is connected to the sensor, extends to the outside of the vacuum vessel 2, and is connected to the thermometer outside the vacuum vessel 2. The temperature information obtained by the sensor can be confirmed by the thermometer.

[0055] The position of point 60 is preferably the same as that of support rod 40, and is preferably the center of the bore of support rod 40. By setting the position of point 60 in this manner, temperature sensor 61 can measure the temperature at the same location where temperature sensor 41 attached to support rod 40 actually measures the temperature of wafer WF1.

[0056] The wafer WF2 with the temperature sensor 61 attached thereto is placed inside the processing chamber 4 in place of the wafer WF1, and the inside of the processing chamber 4 is evacuated to a high vacuum from the opening 15 by the vacuum exhaust device 16. A voltage is applied from the electrode power supply 17 to the multiple electrodes 32 to generate electrostatic force. This causes the wafer WF1 to be attracted to the protrusion 31a. In this state, a voltage is applied from the lamp power supply 13 to the lamp 11, causing the lamp 11 to emit light. The wafer WF2 is heated by the infrared light emitted from the emitted lamp 11 that is transmitted through the quartz window 14 and enters the processing chamber 4.

[0057] The temperature of the wafer WF2 in a heated state is measured by multiple temperature sensors 61 and the temperature sensor 41 attached to the support rod 40, and the respective results are compared. Fig. 6 is an example of a database showing the correspondence between the temperatures obtained by measurement. Fig. 6 shows the time change of the average value of the temperatures measured by the multiple temperature sensors 61 (TC wafer temperature) and the time change of the temperature measured by the temperature sensor 41 (PT sensor temperature).

[0058] Such measurements are performed by varying the voltage (IR output) applied from the lamp power supply 13 to the lamps 11 and the pressure (He pressure) of the heat transfer gas supplied to the space 50 below the wafer WF2 as parameters. As a result, a graph such as that shown in Fig. 6 is created as a database for each condition. The database is recorded in the memory unit C0c of the overall control unit C0 shown in Fig. 7. That is, the overall control unit C0 has, as a database, a correspondence between the heating temperature by the lamps 11 under a plurality of applied voltages and the gas temperature under a plurality of pressures.

[0059] Using the database created in this manner, the average temperature that is expected to be measured by the multiple temperature sensors 61 can be calculated from the temperature measured by the temperature sensor 41.

[0060] A method for correcting the heating temperature by the lamps 11 during processing of the wafer WF1 will be described below. As shown in Fig. 7, the overall control unit C0 has a command unit C0a, a collation unit C0b, and a storage unit C0c. The command unit C0a is electrically connected to each of the control units C1 to C5, and is a mechanism for controlling the drive and operation of these units and communicating with them.

[0061] The gas temperature measured by the temperature sensor 41 is sent to the command unit C0a via the sensor control unit C5. At the same time, the pressure of the gas supplied from the gas supply pipe 24 to the space 50 is also sent to the command unit C0a via the gas flow rate control unit C4. The command unit C0a sends these numerical values ​​to the collation unit C0b. As described above, the memory unit C0c stores a database created using the wafer WF2. The collation unit C0b reads out this database from the memory unit C0c.

[0062] The collation unit C0b compares the gas temperature and gas pressure sent from the command unit C0a with a database to estimate the current heating temperature of the lamp 11 and the current applied voltage of the lamp power supply 13. In other words, the collation unit C0b can know how much the current heating temperature differs from the desired heating temperature. Then, the collation unit C0b sends information on the applied voltage of the lamp power supply 13 corresponding to the desired heating temperature to the command unit C0a.

[0063] Based on the information sent from the comparison unit C0b, the command unit C0a controls the voltage applied to the lamp power supply 13 so that the heating temperature by the lamps 11 is corrected to a desired heating temperature. As a result, the temperature of the gas measured by the temperature sensor 41 is also corrected to the desired temperature. That is, the temperature of the wafer WF1 can be quickly changed to the desired temperature.

[0064] By repeating such control by the overall control unit C0, the heating temperature by the lamps 11 can be controlled to an appropriate temperature during processing of the wafer WF1, and the temperature of the wafer WF1 can be controlled to an appropriate temperature.

[0065] <Plasma treatment method> A plasma processing method performed on a wafer WF1 using a plasma processing apparatus 1 as shown in FIG. 8 will be described below.

[0066] In step S1, a vacuum transfer device such as a robot arm is used to transfer the wafer WF1 from the outside of the plasma processing device 1 to the inside of the vacuum chamber 2. Next, as shown in FIG. 2, the wafer WF1 is placed on the upper end of the support rod 40 with the upper end of the support rod positioned above the protruding portion 31a. Next, the vacuum transfer device is removed from the vacuum chamber 2, and the inside of the vacuum chamber 2 is sealed. Next, the inside of the processing chamber 4 is evacuated to a high vacuum through the opening 15 by the vacuum exhaust device 16. This adjusts the pressure inside the processing chamber 4 to a value within a range suitable for plasma processing.

[0067] In step S2, the support rod 40 is moved downward by the moving mechanism 42, thereby placing the wafer WF1 on the protruding portion 31a, as shown in Fig. 3. Then, the support rod 40 is positioned inside the through-hole 25 so as to be separated from the wafer WF1.

[0068] In step S3, a voltage is applied from the electrode power supply 17 to the multiple electrodes 32 to generate an electrostatic force. This causes the wafer WF1 to be attracted to the protruding portion 31a so as to move away from the upper surface of the insulating layer 31. A space 50 is formed between the wafer WF1 and the upper surface of the insulating layer 31 surrounded by the protruding portion 31a. The inside of the gas supply pipe 24, the space 50, and the inside of the through hole 25 are then in communication with each other.

[0069] In step S4, gas is supplied from the gas supply pipe 24 to the space 50, and the gas flows from the space 50 into the through-hole 25. Also, a coolant whose temperature has been adjusted by the coolant control unit C3 is caused to flow through the flow path 21 provided inside the sample stage 20. This promotes the transfer of heat from the wafer WF1, and the temperature of the wafer WF1 is adjusted to a value within a range appropriate for starting the plasma processing.

[0070] In step S5, microwaves are output from the high frequency power supply 8, and a processing gas is supplied from the gas supply device 10 to the inside of the plasma generation chamber 3, thereby generating plasma inside the plasma generation chamber 3. The processing gas (radicals) excited by the plasma flows out from the plasma generation chamber 3 to the processing chamber 4 through the multiple holes 6. Some of these radicals are adsorbed onto the surface of the wafer WF1, thereby forming a reaction layer on the surface of the wafer WF1.

[0071] In step S6, the temperature of the gas is measured using temperature sensor 41 inside through hole 25. The measured gas temperature is transmitted to sensor control unit C5 (overall control unit C0).

[0072] In step S7, the wafer WF1 is heated by the lamps 11. This heating step is performed by applying a voltage to the lamps 11 from the lamp power supply 13. By applying thermal energy to the surface of the wafer WF1 for a certain period of time, the reaction layer formed on the surface of the wafer WF1 is detached from the surface of the wafer WF1.

[0073] Here, as described with reference to FIGS. 5 to 7, by using a method of correcting the heating temperature by the lamps 11 to a desired heating temperature, the temperature of the wafer WF1 is controlled to become a desired temperature.

[0074] In step S8, after the desired processing of the wafer WF1 is completed, the plasma is stopped. Then, after the electrostatic force is removed and the wafer WF1 is released from the suction, the arm of the vacuum transfer device enters the inside of the processing chamber 4, and the processed wafer WF1 is transferred to the outside of the plasma processing device 1.

[0075] Thus, according to the plasma processing apparatus 1 of the first embodiment, the temperature of the gas supplied to the space 50 is measured by the temperature sensor 41 inside the through hole 25 communicating with the space 50. The gas is in direct contact with the wafer WF1 in the space 50, and is the gas to which the temperature of the wafer WF1 is transmitted. This improves the accuracy of the temperature measurement process of the wafer WF1, which is the object to be processed. Furthermore, the temperature measurement by the temperature sensor 41 can be performed in a short time, thereby improving the throughput of the temperature measurement process.

[0076] Furthermore, by using a database of previously measured data, the voltage applied to the lamp power supply 13 can be controlled so that the heating temperature of the lamps 11 is corrected to a desired heating temperature. This makes it possible to quickly change the temperature of the wafer WF1 to a desired temperature. This further improves the throughput of the temperature measurement process.

[0077] Although the present invention has been specifically described above based on the above embodiment, the present invention is not limited to the above embodiment and can be modified in various ways without departing from the spirit of the present invention. [Explanation of symbols]

[0078] 1. Plasma processing equipment 2 Vacuum container 3. Plasma generation chamber 4 Processing Room 5 Plate 6 holes 7 Waveguide 8 High frequency power supply 9 Gas introduction pipe 10 Gas supply equipment 11 Lamp 12 Protective plate 13 Lamp power supply 14 Window section 15 Opening 16 Vacuum exhaust device 17 Electrode power supply 20 Sample stage 21 Flow Path 22 Refrigerant supply pipe 23 Refrigerant discharge pipe 24 Gas supply pipe 25 Through hole 30 Electrostatic Chuck 31 Insulating layer 31a Protrusion 32 electrodes 40 Support rod 41 Temperature Sensor 42 Moving mechanism 43 Bulkhead 44 Conductor 50 space 60 points 61 Temperature Sensor C0 Overall control unit C0a command section C0b Matching section C0c memory section C1 Lamp control unit C2 Electrode control unit C3 Refrigerant control unit C4 Gas flow control section C5 Sensor control unit WF1 wafer WF2 wafer

Claims

1. A vacuum vessel; a processing chamber provided inside the vacuum vessel; A sample stage provided in the processing chamber; an electrostatic chuck including an insulating layer provided on an upper portion of the sample stage, a protrusion provided along an outer periphery of the insulating layer and protruding from an upper surface of the insulating layer, and a plurality of electrodes provided inside the insulating layer; a gas supply pipe for supplying a first gas from a gas supply source provided outside the vacuum vessel to an upper surface of the insulating layer; a through hole penetrating the insulating layer and the sample stage so as to reach an upper surface of the insulating layer; A support rod provided inside the through hole; A moving mechanism for moving the support rod in a vertical direction; Equipped with A temperature sensor is attached to the support rod at a position away from the upper end of the support rod, a first gas supply pipe for supplying a first gas to a first space between the wafer and the top surface of the insulating layer surrounded by the protrusion; and a temperature sensor for measuring a temperature of the first gas that flows from the first space into the through hole.

2. 2. The plasma processing apparatus according to claim 1, A flow path for a coolant to flow is provided inside the sample stage, A partition wall is provided on the inner wall of the through hole, The partition is made of a material having a lower thermal conductivity than a material constituting the sample stage.

3. 2. The plasma processing apparatus according to claim 1, a lamp for heating the wafer; a lamp power supply for applying a voltage to the lamp; Further comprising: the lamp is provided above the processing chamber and outside the vacuum vessel; The lamp power supply is electrically connected to the lamp.

4. 4. The plasma processing apparatus according to claim 3, a control unit electrically connected to the temperature sensor, the lamp power supply, and the gas supply pipe and configured to control the driving of these components; The control unit controls the applied voltage of the lamp power supply based on the temperature of the first gas measured by the temperature sensor and the pressure of the first gas supplied from the gas supply pipe to the first space, so that the heating temperature by the lamp becomes a desired heating temperature.

5. 5. The plasma processing apparatus according to claim 4, the control unit has a database of correspondence relationships between heating temperatures by the lamp under a plurality of applied voltages and temperatures of the first gas under a plurality of pressures; the control unit estimates the current heating temperature by the lamp and the current applied voltage of the lamp power supply by comparing the temperature of the first gas measured by the temperature sensor and the pressure of the first gas supplied from the gas supply pipe to the first space with the database, and corrects the applied voltage of the lamp power supply so that the heating temperature by the lamp becomes a desired heating temperature.

6. A vacuum vessel; a processing chamber provided inside the vacuum vessel; A sample stage provided in the processing chamber; an electrostatic chuck including an insulating layer provided on an upper portion of the sample stage, a protrusion provided along an outer periphery of the insulating layer and protruding from an upper surface of the insulating layer, and a plurality of electrodes provided inside the insulating layer; an electrode power supply electrically connected to the plurality of electrodes; a gas supply pipe for supplying a first gas from a gas supply source provided outside the vacuum vessel to an upper surface of the insulating layer; a through hole penetrating the insulating layer and the sample stage so as to reach an upper surface of the insulating layer; A support rod provided inside the through hole; A moving mechanism for moving the support rod in a vertical direction; A plasma processing method for a wafer using a plasma processing apparatus comprising: (a) placing the wafer on the upper end of the support rod in a state where the upper end of the support rod is positioned above the protruding portion; (b) after the step (a), a step of moving the support rod downward by the moving mechanism to place the wafer on the protruding portion and position the support rod inside the through hole so as to be separated from the wafer; (c) after the step (b), applying a voltage from the electrode power supply to the plurality of electrodes to adsorb the wafer onto the protruding portion so as to separate the wafer from the upper surface of the insulating layer; (d) after the step (c), supplying the first gas from the gas supply pipe to a first space between the upper surface of the insulating layer surrounded by the protruding portion and the wafer, and causing the first gas to flow from the first space into the through hole; (e) measuring the temperature of the first gas inside the through hole after the step (d); having A temperature sensor is attached to the support rod at a position away from the upper end of the support rod, The plasma processing method, wherein the step (e) is performed using the temperature sensor.

7. 7. The plasma processing method according to claim 6, (f) after the step (c), a step of flowing a coolant through a flow path provided inside the sample stage; Further comprising: A partition wall is provided on the inner wall of the through hole, A plasma processing method, wherein the partition is made of a material having a lower thermal conductivity than a material constituting the sample stage.

8. 7. The plasma processing method according to claim 6, (g) after step (d), heating the wafer; Further comprising: the plasma processing apparatus further includes a lamp for heating the wafer, and a lamp power supply for applying a voltage to the lamp; the lamp is provided above the processing chamber and outside the vacuum vessel; the lamp power supply is electrically connected to the lamp; The plasma processing method, wherein the step (g) is performed by applying a voltage to the lamp from the lamp power supply.

9. 9. The plasma processing method according to claim 8, a control unit electrically connected to the temperature sensor, the lamp power supply, and the gas supply pipe and configured to control the driving of these components; the control unit controls the applied voltage of the lamp power supply so that the heating temperature by the lamp is corrected to a desired heating temperature based on the temperature of the first gas measured by the temperature sensor and the pressure of the first gas supplied from the gas supply pipe to the first space.

10. 10. The plasma processing method according to claim 9, the control unit has a database of correspondence relationships between heating temperatures by the lamp under a plurality of applied voltages and temperatures of the first gas under a plurality of pressures; the control unit compares the temperature of the first gas measured by the temperature sensor and the pressure of the first gas supplied from the gas supply pipe to the first space with the database, thereby estimating the current heating temperature by the lamp and the current applied voltage of the lamp power supply, and controls the applied voltage of the lamp power supply so that the heating temperature by the lamp is corrected to a desired heating temperature.

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