JP2015106587A - Method for coating electrostatic chuck and plasma processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for coating an electrostatic chuck and a plasma processing apparatus enabling the temperature of a wafer to be properly controlled.SOLUTION: The method for coating an electrostatic chuck is provided that includes a step in which, before a substrate is subjected to plasma processing, gas containing C and F is supplied while the substrate is not mounted on the electrostatic chuck, plasma is generated from the supplied gas, and a part or the whole of the electrostatic chuck is coated in such a way that a film formed on the center side of the electrostatic chuck by the generated plasma is formed to be thicker than that formed on the edge side of the electrostatic chuck.

Description

  The present invention relates to an electrostatic chuck coating method and a plasma processing apparatus.

  Waferless dry cleaning (WLDC) is known in which the inside of a chamber is cleaned without placing a wafer (see, for example, Patent Document 1). In Patent Document 1, the inside of the chamber is cleaned in a state where the wafer is not placed before processing the wafer, a precoat gas is allowed to flow into the chamber after the cleaning, a precoat film is formed on the surface in the chamber, and then the wafer is processed. Technology is disclosed.

Japanese Patent No. 5139059

  However, deposits adhering to the surface of the electrostatic chuck are mainly adhered to the surface of the electrostatic chuck being exposed to plasma during waferless dry cleaning, and can be removed by waferless dry cleaning. Have difficulty.

  Therefore, with the execution of waferless dry cleaning, deposits adhere to the surface of the electrostatic chuck, and the surface of the electrostatic chuck changes over time. Such a change with time of the surface of the electrostatic chuck has a problem that it is difficult to appropriately control the temperature of the wafer.

  In Patent Document 1, the surface in the chamber is pre-coated with chlorine or the like having affinity for oxygen, thereby reducing the amount of oxygen radicals in the plasma, thereby optimizing the selectivity in etching the photoresist. . Therefore, with the technique disclosed in Patent Document 1, it is difficult to properly control the temperature of the wafer based on the change over time of the surface of the electrostatic chuck due to the deposit attached to the surface of the electrostatic chuck.

  In view of the above problems, an object of one aspect is to provide an electrostatic chuck coating method and a plasma processing apparatus capable of appropriately controlling the wafer temperature.

In order to solve the above problem, according to one aspect,
Before plasma processing of the substrate, a gas containing C and F is supplied without placing the substrate on the electrostatic chuck, and plasma is generated from the supplied gas.
A part or all of the electrostatic chuck is coated such that the film formed on the center side of the electrostatic chuck is formed thicker than the film formed on the edge side of the electrostatic chuck by the generated plasma. To
An electrostatic chuck coating method comprising the steps is provided.

Moreover, in order to solve the said subject, according to another aspect,
Before plasma treatment of the substrate, a gas containing C, H and F is supplied without placing the substrate on the electrostatic chuck, and plasma is generated from the supplied gas.
Coating a part or all of the electrostatic chuck such that the film on the edge side of the electrostatic chuck is formed thicker than the film on the center side of the electrostatic chuck by the generated plasma.
An electrostatic chuck coating method comprising the steps is provided.

Moreover, in order to solve the said subject, according to another aspect,
Before plasma processing of the substrate, a film having a desired thickness distribution is formed on the electrostatic chuck based on a recipe in which a plurality of types of profiles relating to the thickness of the film formed on the electrostatic chuck are stored in the storage unit. A control unit for controlling supply of a gas containing C and F, or a gas containing C, H and F,
A gas supply unit that supplies a gas containing C and F or a gas containing C, H and F in a state where the substrate is not placed on the electrostatic chuck in accordance with control by the control unit,
The control unit controls to coat a part or all of the electrostatic chuck with a film having a desired thickness distribution by plasma generated from the supplied gas.
A plasma processing apparatus is provided.

  According to one aspect, it is possible to provide an electrostatic chuck coating method and a plasma processing apparatus capable of appropriately controlling the wafer temperature.

The figure which showed an example of the result of the temperature control with respect to the unused and used electrostatic chuck. 1 is an overall configuration diagram of a plasma processing apparatus according to an embodiment. The figure which showed an example of thickness distribution of the coating film which concerns on one Embodiment. The figure which showed the example of the presence or absence of the coating film which concerns on one Embodiment, and wafer temperature. The figure which showed an example of the thickness of the coating film and wafer temperature which concern on one Embodiment. The flowchart which showed an example of the recipe selection process for the coating which concerns on one Embodiment. The flowchart which showed an example of the 1st coating process which concerns on one Embodiment. The flowchart which showed an example of the 2nd coating process which concerns on one Embodiment.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In addition, in this specification and drawing, about the substantially same structure, the duplicate description is abbreviate | omitted by attaching | subjecting the same code | symbol.
(Introduction)
Deposits adhering to the surface of the electrostatic chuck are mainly adhered to the surface of the electrostatic chuck exposed to plasma during waferless dry cleaning, and are difficult to remove by waferless dry cleaning. is there.

  Therefore, with the execution of waferless dry cleaning, deposits adhere to the surface of the electrostatic chuck, and the surface of the electrostatic chuck changes over time. Such a change with time of the surface of the electrostatic chuck makes it difficult to properly control the temperature of the wafer.

  For example, with an unused electrostatic chuck and a used electrostatic chuck that has been used for several thousand hours or more, the temperature of the electrostatic chuck is controlled to a different value even if the same temperature control is performed on the electrostatic chuck. May be.

  In FIG. 1, an unused electrostatic chuck (New ESC) and a used electrostatic chuck (Used ESC) that has been used for several thousand hours or more (hereinafter also simply referred to as “used electrostatic chuck”). An example of the temperature distribution of the wafer when the same temperature control is performed on. At this time, an organic compound (polymer) containing carbon (C) and fluorine (F) is attached to the surface of the used electrostatic chuck during waferless dry cleaning (WLDC).

  Considering the wafer temperature shown on the vertical axis with respect to the CF compound deposition amount (nm) shown on the horizontal axis, when an unused electrostatic chuck is used, compared to using a used electrostatic chuck. However, the temperature near the middle from the wafer center was higher than the temperature near the edge. In a used electrostatic chuck, this is considered to be caused mainly by the CF compound adhering to the surface of the chuck and lowering the temperature. Such variation in the temperature control result of the wafer based on the change in the surface of the electrostatic chuck over time is undesirable because it affects the plasma process characteristics such as the etching rate.

  Therefore, in the following, an embodiment of an electrostatic chuck coating method capable of appropriately controlling the wafer temperature and an embodiment of a plasma processing apparatus for executing the coating method will be described.

[Overall configuration of plasma processing apparatus]
First, a plasma processing apparatus according to an embodiment of the present invention will be described as an example. The plasma processing apparatus is an apparatus that executes a coating method of an electrostatic chuck and can form a coating film on the electrostatic chuck. FIG. 2 is a cross-sectional view of the plasma processing apparatus 1 according to the present embodiment. Here, as an example, a parallel plate type plasma processing apparatus in which a lower electrode 20 (mounting table) and an upper electrode 25 (shower head) are opposed to each other in a chamber and a processing gas is supplied from the upper electrode 25 into the chamber is taken as an example. explain.

  The plasma processing apparatus 1 includes a chamber 10 made of a conductive material such as aluminum and a gas supply source 15 that supplies a gas into the chamber 10. The chamber 10 is grounded. The gas supply source 15 supplies a specific gas in each of the coating process, the etching process, and the waferless dry cleaning (WLDC) process.

  The chamber 10 is electrically grounded, and a lower electrode 20 and an upper electrode 25 disposed in parallel to face the lower electrode 20 are provided in the chamber 10. The lower electrode 20 also functions as a mounting table for mounting a semiconductor wafer (hereinafter simply referred to as “wafer”). A wafer is an example of a substrate to be etched.

  An electrostatic chuck 106 for electrostatically attracting the wafer is provided on the upper surface of the mounting table (lower electrode 20). The electrostatic chuck 106 has a structure in which a chuck electrode 106a is sandwiched between insulators 106b. A DC voltage source 112 is connected to the chuck electrode 106a, and when a DC voltage is applied from the DC voltage source 112 to the electrode 106a, the wafer is attracted to the electrostatic chuck 106 by Coulomb force.

  The mounting table (lower electrode 20) is supported by the support body 104. A coolant channel 104 a is formed inside the support body 104. A refrigerant inlet pipe 104b and a refrigerant outlet pipe 104c are connected to the refrigerant flow path 104a. For example, cooling water or the like is circulated as appropriate in the refrigerant flow path 104a.

  The heat transfer gas supply source 85 supplies a heat transfer gas such as helium gas (He) or argon gas (Ar) to the back surface of the wafer W on the electrostatic chuck 106 through the gas supply line 130. With this configuration, the temperature of the electrostatic chuck 106 is controlled by the cooling water circulated through the refrigerant flow path 104a and the heat transfer gas supplied to the back surface of the wafer W. As a result, the wafer can be controlled to a predetermined temperature.

  The lower electrode 20 is connected to a power supply device 30 that supplies two-frequency superimposed power. The power supply device 30 includes a first high-frequency power source 32 that supplies a first high-frequency power (plasma generation high-frequency power) having a first frequency, and a second high-frequency power (for generating a bias voltage) that is lower than the first frequency. A second high-frequency power source 34 for supplying high-frequency power). The first high frequency power supply 32 is electrically connected to the lower electrode 20 via the first matching unit 33. The second high frequency power supply 34 is electrically connected to the lower electrode 20 via the second matching unit 35. The first high frequency power supply 32 supplies a first high frequency power of 40 MHz, for example. The second high frequency power supply 34 supplies, for example, a second high frequency power of 3.2 MHz.

  The first and second matching units 33 and 35 are for matching the load impedance to the internal (or output) impedance of the first and second high-frequency power sources 32 and 34, respectively, and plasma is generated in the chamber 10. The internal impedance and load impedance of the first and second high frequency power supplies 32 and 34 seem to coincide with each other.

  The upper electrode 25 is attached to the ceiling portion of the chamber 10 via a shield ring 40 that covers the peripheral edge portion of the upper electrode 25. The upper electrode 25 may be electrically grounded as shown in FIG. 1, or a variable direct current power source (not shown) may be connected so that a predetermined direct current (DC) voltage is applied to the upper electrode 25. Also good.

  A gas inlet 45 for introducing gas from the gas supply source 15 is formed in the upper electrode 25. Further, a center side diffusion chamber 50 a and an edge side diffusion chamber 50 b for diffusing the gas branched and introduced from the gas introduction port 45 are provided inside the upper electrode 25.

  A number of gas supply holes 55 for supplying the gas from the diffusion chamber 50 into the chamber 10 are formed in the upper electrode 25. Each gas supply hole 55 is arranged so that gas can be supplied between the wafer W placed on the lower electrode 20 and the upper electrode 25.

  The gas from the gas supply source 15 is supplied to the diffusion chambers 50 a and 50 b through the gas inlet 45, diffuses and is distributed to the gas supply holes 55, and is discharged from the gas supply hole 55 toward the lower electrode 20. Is done. From the above, the upper electrode 25 having such a configuration also functions as a gas shower head that supplies gas.

  An exhaust port 60 is formed in the bottom surface of the chamber 10, and the interior of the chamber 10 can be maintained at a predetermined degree of vacuum by exhausting by the exhaust device 65 connected to the exhaust port 60. A gate valve G is provided on the side wall of the chamber 10. The gate valve G opens and closes the loading / unloading port when the wafer W is loaded and unloaded from the chamber 10.

  The plasma processing apparatus 1 is provided with a control unit 100 that controls the operation of the entire apparatus. The control unit 100 includes a CPU (Central Processing Unit) 105 and recording areas of a ROM (Read Only Memory) 110 and a RAM (Random Access Memory) 115. The CPU 105 executes desired processing such as coating processing and etching described later, and cleaning processing according to various recipes stored in these storage areas. The recipe includes process time, pressure (gas exhaust), high-frequency power and voltage, various process gas flow rates, chamber temperature (upper electrode temperature, chamber side wall temperature, ESC temperature, etc.), which are device control information for process conditions Is described. The recipes indicating these programs and processing conditions may be stored in a hard disk or semiconductor memory, or stored in a storage medium readable by a portable computer such as a CD-ROM or DVD. You may set it to the predetermined position of an area | region.

  The overall configuration of the plasma processing apparatus 1 according to this embodiment has been described above. By the plasma processing apparatus 1 having such a configuration, the processing is repeated in the order of coating processing, etching, etc., which will be described later, and waferless dry cleaning processing.

  In the coating process, coating gas and high frequency power are supplied from the gas supply source 15 into the chamber 10 without the wafer W being placed on the electrostatic chuck 106, and plasma is generated. A desired coating film is formed on the surface of the electrostatic chuck 106 by the generated plasma.

  In processing such as etching, the opening and closing of the gate valve G is controlled, and the wafer W is loaded into the chamber 10 and placed on the lower electrode 20. Next, a process gas such as etching and high-frequency power are supplied into the chamber 10, and a desired process such as plasma etching is performed on the wafer W by the generated plasma. After the processing, the opening and closing of the gate valve G is controlled, and the wafer W is unloaded from the chamber 10.

  In the waferless dry cleaning process, the cleaning gas and the high frequency power are supplied from the gas supply source 15 into the chamber 10 without the wafer W being placed on the electrostatic chuck 106, and plasma is generated. The inside of the chamber 10 is cleaned by the generated plasma. Thereby, the coating film on the surface of the electrostatic chuck 106 is removed.

  Hereinafter, the electrostatic chuck coating method according to the present embodiment will be mainly described.

[coating]
A change in the temperature of the wafer when a film having a convex profile distribution is coated on the surface of the electrostatic chuck will be described with reference to FIGS. FIG. 3 shows an example of a thickness distribution of a coating film according to an embodiment and process conditions for forming a coating film having the thickness distribution. FIG. 4 shows an example of the presence / absence of a coating film and the wafer temperature according to an embodiment. FIG. 5 shows an example of the thickness of the coating film and the wafer temperature according to an embodiment.

  FIG. 3A shows the deposition amount (that is, the thickness of the coating film) on the surface of the electrostatic chuck at a radial position (hereinafter referred to as “wafer position”) of a wafer having a diameter of 300 mm. X and Y indicate the amount of deposition at each wafer position having an orthogonal diameter.

FIG. 3A shows a film having a convex profile distribution in which the center-to-middle coating film on the surface of the electrostatic chuck is thicker than the middle-to-edge coating film. Process conditions for forming a coating film having a film thickness distribution shown in FIG.
<Process conditions: Convex profile>
Pressure 400mTorr (53.3Pa)
First high frequency power 800W
Power of second high frequency power 0W
Gas type and gas flow rate C ₄ F ₆ (hexafluoro1,3 butadiene) / C ₄ F ₈ (perfluorocyclobutane) / C ₃ F ₈ (octafluoropropane) / Ar (argon) = 100/85/95 / 100 sccm
Gas supply ratio (shower head) Center: Edge = 50: 50
Electrostatic chuck temperature control 20 ℃
Deposition time 20 seconds Under the above process conditions, a film formation process is performed using the plasma processing apparatus 1 according to the present embodiment. At that time, the control unit 100 controls the gas supply source 15 to supply a coating gas containing carbon (C) and fluorine (F) without placing the wafer on the electrostatic chuck 106. Further, the control unit 100 performs control so that the first high-frequency power having the above power is supplied into the chamber 10. The plasma generated as a result is subjected to a film formation process for a predetermined film formation time. As a result, a compound containing carbon (C) and fluorine (F) adheres to the surface of the electrostatic chuck, and the thickness of the middle from the center of the electrostatic chuck becomes thicker than the thickness from the middle to the edge. A CF-based coating film having the thickness distribution shown in FIG.

  An example of the effect that the surface of the electrostatic chuck is coated with the coating film having the thickness distribution shown in FIG. 3A will be described with reference to FIGS. The temperature of the wafer shown in FIGS. 4 and 5 is an example of the temperature of the wafer obtained as a result of performing the same temperature control on the coated electrostatic chuck and the uncoated electrostatic chuck.

  As a result, when the temperature was controlled for the electrostatic chuck before coating, the average temperature of the wafer was 62.5 ° C. At this time, the wafer center temperature was 62.2 ° C. and the edge temperature was 64.9 ° C.

  In contrast, when the temperature of the electrostatic chuck after coating with the convex profile coating film shown in FIG. 3A was controlled, the average temperature of the wafer was 57.5 ° C. At this time, the wafer center temperature was 53.8 ° C. and the edge temperature was 64.7 ° C.

  Further, when the temperature was controlled with respect to the electrostatic chuck after removing the coating film, the average temperature of the wafer was 62.0 ° C. At this time, the wafer center temperature was 60.9 ° C. and the edge temperature was 63.6 ° C.

  From this result, if the electrostatic chuck is coated with a CF coating film whose center-to-middle film thickness is thicker than the middle-to-edge film thickness, the temperature near the wafer center decreases, and the coating film is removed from the electrostatic chuck. It can be seen that the removal generally returns to the temperature control state before coating.

  This result is also shown in FIG. FIG. 5 is a diagram illustrating an example of the wafer temperature with respect to the thickness of the coating film (CF compound deposition amount) according to an embodiment. As shown in FIG. 5, the coating film on the surface of the electrostatic chuck has an effect of lowering the wafer temperature when the film thickness is 100 nm or less, and when the film thickness is 100 nm or more, the wafer temperature stops decreasing and changes almost. do not do. In other words, the optimum film thickness can be achieved by changing the film thickness with the desired wafer temperature as a target.

  From the above, by forming a CF-based coating film on the electrostatic chuck, the temperature of the wafer can be controlled so that the temperature from the center to the middle is lower than the temperature from the middle to the edge. In particular, temperature control may be difficult on the surface of an unused electrostatic chuck because deposits are not attached. Even in this case, the wafer can be controlled to have a desired temperature distribution by forming a CF-based coating film on an unused electrostatic chuck. In particular, the coating film formed based on the process conditions of the convex profile is effective when it is desired to control the temperature of the region from the center to the middle of the wafer to be lowered.

  In the process conditions of the convex profile, a mixed gas (CF-based gas) containing C and F or the like is used as the coating gas, but the CF-based gas may be a single gas or a mixed gas. The coating gas is a gas that does not contain hydrogen H.

The coating gas may or may not include argon gas (Ar), oxygen gas (O ₂ ), and helium gas (He). These gases are mainly used for the purpose of reducing the film formation rate or for the purpose of uniformity control (adjustment of the profile of the coating film).

Next, process conditions for coating a film having a concave profile distribution will be described. FIG. 3B shows a film having a concave profile distribution in which the middle-to-edge coating film on the surface of the electrostatic chuck is thicker than the middle-to-middle coating film. Process conditions for forming a coating film having a film thickness distribution shown in FIG.
<Process conditions: concave profile>
Pressure 200mTorr (26.7Pa)
First high frequency power 800W
Power of second high frequency power 0W
Gas type and gas flow rate CH ₂ F ₂ (methane difluoride) / CHF ₃ (methyl trifluoride) = 200/100 sccm
Gas supply ratio (shower head) Center: Edge = 50: 50
Electrostatic chuck temperature control 20 ° C (fixed)
Deposition time 60 seconds Under the above process conditions, a film formation process is performed using the plasma processing apparatus 1 according to the present embodiment. At that time, the control unit 100 is supplied with a coating gas containing carbon (C), hydrogen (H), and fluorine (F) from the gas supply source 15 without placing the wafer on the electrostatic chuck 106. To control. Further, the control unit 100 performs control so that the first high-frequency power having the above power is supplied into the chamber 10. The plasma generated as a result is subjected to a film formation process for a predetermined film formation time. As a result, a coating film having a thickness distribution shown in FIG. 3B is formed in which the film thickness from the middle to the edge of the electrostatic chuck is larger than the film thickness from the center to the middle.

  From the above, by forming a CHF-based coating film on the electrostatic chuck, the wafer temperature can be controlled so that the temperature from the middle to the edge is lower than the temperature from the center to the middle. In particular, temperature control may be difficult on the surface of an unused electrostatic chuck because deposits are not attached. Even in that case, the wafer can be controlled to have a desired temperature distribution by forming a CHF-based coating film on an unused electrostatic chuck. Particularly, the coating film formed based on the process conditions of the concave profile is effective when it is desired to lower the temperature of the region from the middle to the edge of the wafer.

In the concave profile process conditions, a mixed gas (CHF-based gas) containing C, H, and F is used as a coating gas. However, the CHF-based gas may be a single gas or a mixed gas. The coating gas may or may not include argon gas (Ar), oxygen gas (O ₂ ), and helium gas (He).

  In the above, the process conditions concerning the coating film (convex profile and concave profile) of the electrostatic chuck according to the present embodiment and the effect on the temperature control of the wafer depending on whether or not the electrostatic chuck is coated have been described.

[Coating process]
Next, processes including coating and etching processes for forming the coating film and processes including cleaning will be described. FIG. 6 is a flowchart illustrating an example of a recipe selection process for coating according to an embodiment. FIG. 7 is a flowchart illustrating an example of a first coating process according to an embodiment. FIG. 8 is a flowchart illustrating an example of a second coating process according to an embodiment.

(Recipe selection process)
When the recipe selection process for coating shown in FIG. 6 is started, the control unit 100 acquires the coating conditions (step S10). For example, the control unit 100 acquires a condition such as a condition that the temperature is lowered from the center to the middle area and a condition that the temperature is lowered from the middle to the edge area. The acquisition of the condition may be performed by causing an administrator or the like to input information regarding the condition.

  Next, the control unit 100 determines the type of profile based on the acquired condition (step S12). When the temperature drop in the middle area from the center is a condition, the profile type is determined to be a convex profile, and the control unit 100 acquires a recipe corresponding to the convex profile (step S14), and performs the first coating process (FIG. The process proceeds to 7) (step S16). A recipe corresponding to the convex profile is stored in advance in a storage unit such as the RAM 115.

  On the other hand, when the condition is a temperature drop from the middle to the edge region, the profile type is determined to be a concave profile in step S12, and the control unit 100 acquires a recipe corresponding to the concave profile from the storage unit (step S18). Then, the process proceeds to the second coating process (FIG. 8) or the like (step S20). A recipe corresponding to the concave profile is stored in advance in a storage unit such as the RAM 115.

[First coating treatment]
(Coating treatment)
When the first coating process shown in FIG. 7 called in step S16 in FIG. 6 is started, the control unit 100 executes the electrostatic chuck coating method according to the present embodiment. That is, the control unit 100 executes a coating process on the electrostatic chuck based on the recipe corresponding to the convex profile (step S160).

Specifically, the control unit 100 controls the inside of the chamber according to a recipe corresponding to the convex profile. Thereby, C ₄ F ₆ gas, C ₄ F ₈ gas, C ₃ F ₈ gas and Ar gas are supplied from the gas supply source 15 into the chamber without placing the wafer on the electrostatic chuck. Further, the first high frequency power of 800 W is supplied from the power supply device 30. As a result, plasma is generated. A part or all of the electrostatic chuck is made of CF-based so that the film formed on the center side of the electrostatic chuck is formed thicker than the film formed on the edge side of the electrostatic chuck by the generated plasma. Coated with membrane. As an example of the coated film, as shown in FIG. 3A, a coating film in which the film thickness from the center of the electrostatic chuck to the middle is thicker than the film thickness from the middle to the edge is mentioned.

The gas supplied from the gas supply source 15 may be a single gas of at least one of C ₄ F ₆ gas, C ₄ F ₈ gas, and C ₃ F ₈ gas, or may be a mixed gas. Good. Ar gas may not be contained. That is, the gas supplied from the gas supply source 15 may be a gas containing C and F. In the first coating process, H gas is not contained in the supplied gas.

(Desired processing such as etching)
Next, the control unit 100 places the wafer on the electrostatic chuck, supplies a desired process gas into the chamber, and generates plasma with the power of the first high-frequency power of 3000 to 4000 W, for example. A desired process such as etching or film formation is performed on the wafer by the generated plasma (step S162). At this time, the temperature of the electrostatic chuck is controlled by cooling water to be circulated through the refrigerant flow path 104a and heat transfer gas supplied to the back surface of the wafer W. In particular, in the present embodiment, the electrostatic chuck is pre-coated, and the pre-coated film has a film thickness from the center of the electrostatic chuck to the middle that is greater than that from the middle to the edge. Therefore, in the present embodiment, the coating film having the above thickness can lower the temperature on the middle side from the center of the electrostatic chuck and improve the temperature controllability of the wafer.

(Waferless dry cleaning process)
After the processed wafer is unloaded from the chamber, the control unit 100 supplies a cleaning gas into the chamber without generating the wafer on the electrostatic chuck, and generates plasma with high-frequency power. The inside of the chamber including the surface of the electrostatic chuck is cleaned by the generated plasma (step S164). Thereby, the coating film on the surface of the electrostatic chuck can be removed. As an example of the cleaning gas, a gas including helium gas (He), hydrogen gas (H), and oxygen gas (O) may be used.

[Second coating process]
(Coating treatment)
When the second coating process shown in FIG. 8 called in step S20 of FIG. 6 is started, the control unit 100 executes the electrostatic chuck coating method according to the present embodiment. That is, the control unit 100 executes a coating process on the electrostatic chuck based on the recipe corresponding to the concave profile (step S200).

Specifically, the control unit 100 controls the inside of the chamber according to a recipe corresponding to the convex profile. Thus, CH ₂ F ₂ gas and CHF ₃ gas are supplied from the gas supply source 15 into the chamber without placing the wafer on the electrostatic chuck. Further, the first high frequency power of 800 W is supplied from the power supply device 30. As a result, plasma is generated. Part or all of the electrostatic chuck is CHF-based so that the film formed on the edge side of the electrostatic chuck is formed thicker than the film formed on the center side of the electrostatic chuck by the generated plasma. Coated with membrane. As an example of the coated film, as shown in FIG. 3B, a coating film in which the film thickness from the middle to the edge of the electrostatic chuck is thicker than the film thickness from the center to the middle.

Note that the gas supplied from the gas supply source 15 may be a single gas of at least one of CH ₂ F ₂ gas, CHF ₃ gas, and CHF ₂ gas, or a mixed gas. That is, the gas supplied from the gas supply source 15 may be a gas containing C, H, and F. In the second coating process, H gas is contained in the supplied gas.

(Desired processing such as etching)
Next, the control unit 100 places the wafer on the electrostatic chuck, supplies a desired process gas into the chamber, and generates plasma with the power of the first high-frequency power of 3000 to 4000 W, for example. The generated plasma is subjected to a desired process such as etching or film formation (step S202). At this time, the temperature of the electrostatic chuck is controlled by cooling water to be circulated through the refrigerant flow path 104a and heat transfer gas supplied to the back surface of the wafer W. In particular, in this embodiment, the electrostatic chuck is pre-coated, and the film of the pre-coated middle to edge is thicker than the center to middle film thickness. Therefore, in the present embodiment, the coating film having the above thickness can reduce the temperature from the middle to the edge side of the electrostatic chuck and improve the temperature controllability of the wafer.

(Waferless dry cleaning process)
After the processed wafer is unloaded from the chamber, the control unit 100 supplies a cleaning gas into the chamber without generating the wafer on the electrostatic chuck, and generates plasma with high-frequency power. The inside of the chamber including the surface of the electrostatic chuck is cleaned by the generated plasma (step S204). Thereby, the coating film on the surface of the electrostatic chuck can be removed. As an example of the cleaning gas, a gas including helium gas (He), hydrogen gas (H), and oxygen gas (O) may be used.

  The electrostatic chuck coating method according to the present embodiment has been described above. The surface of the electrostatic chuck before the desired processing such as etching can be coated with the coating film by repeatedly performing the above-described plasma coating processing, desired processing such as etching, and waferless dry cleaning processing. it can. Thereby, the temperature of the wafer can be appropriately controlled even by a change with time of the surface of the electrostatic chuck. In particular, even an unused electrostatic chuck can be controlled to have a desired wafer temperature distribution. Further, the coating film can be easily removed by the waferless dry cleaning process. Therefore, since the film thickness and distribution of the coating can be changed for each product type, the versatility is high.

  In the electrostatic chuck coating method according to the present embodiment, in the case of a convex profile, a gas containing C and F is supplied. As a result, a CF-based coating film having a thickness distribution shown in FIG. 3A is formed in which the film thickness from the center of the electrostatic chuck to the middle is larger than the film thickness from the middle to the edge. Thereby, the temperature distribution of the desired wafer can be realized by lowering the temperature on the center side of the wafer.

  In the electrostatic chuck coating method according to this embodiment, in the case of the concave profile, a gas containing C, H, and F is supplied. As a result, a CHF-based coating film having a thickness distribution shown in FIG. 3B is formed in which the film thickness of the edge from the middle of the electrostatic chuck is thicker than the film thickness of the center. Thus, the temperature distribution on the desired wafer can be controlled by lowering the temperature on the edge side of the wafer.

  The waferless dry cleaning process can be omitted. In that case, processes such as coating and etching are repeatedly performed. However, it is preferable to perform a cleaning process for cleaning the inside of the chamber.

  The timing of the coating process on the electrostatic chuck may be before the desired process. Seasoning may be performed to condition the chamber before coating the electrostatic chuck.

  The electrostatic chuck coating method and the plasma processing apparatus have been described above by the above embodiment, but the present invention is not limited to the above embodiment, and various modifications and improvements can be made within the scope of the present invention. . Moreover, it is possible to combine the above-described embodiments and modification examples as long as they do not contradict each other.

  For example, as means for generating plasma in the plasma processing apparatus according to the present invention, capacitively coupled plasma (CCP) generating means, inductively coupled plasma (ICP) generating means, helicon wave excitation Type plasma (HWP: Helicon Wave Plasma) generation means, microwave excitation surface wave plasma generation means including microwave plasma and SPA (Slot Plane Antenna) plasma generated from a radial line slot antenna, electron cyclotron resonance plasma (ECR) Resonance Plasma) generating means, remote plasma generating means using the generating means, and the like can be used.

  The substrate to be treated in the present invention is not limited to the (semiconductor) wafer used in the description in the above embodiment, and for example, a large substrate for a flat panel display, an EL element, or a solar cell It may be a substrate.

DESCRIPTION OF SYMBOLS 1: Plasma processing apparatus 10: Chamber 15: Gas supply source 20: Lower electrode 25: Upper electrode 32: 1st high frequency power supply 34: 2nd high frequency power supply 85: Heat transfer gas supply source 100: Control part 104a: Refrigerant flow path 106 : Electrostatic chuck 130: Gas supply line

Claims (10)

Before plasma processing of the substrate, a gas containing C and F is supplied without placing the substrate on the electrostatic chuck, and plasma is generated from the supplied gas.
A part or all of the electrostatic chuck is coated such that the film formed on the center side of the electrostatic chuck is formed thicker than the film formed on the edge side of the electrostatic chuck by the generated plasma. To
A method for coating an electrostatic chuck including a step. The gas containing C and F is a gas not containing H.
The method for coating an electrostatic chuck according to claim 1. The gas containing C and F includes at least one of C ₄ F ₆ gas, C ₄ F ₈ gas, and C ₃ F ₈ gas.
The electrostatic chuck coating method according to claim 1 or 2. Before plasma treatment of the substrate, a gas containing C, H and F is supplied without placing the substrate on the electrostatic chuck, and plasma is generated from the supplied gas.
Coating a part or all of the electrostatic chuck such that the film on the edge side of the electrostatic chuck is formed thicker than the film on the center side of the electrostatic chuck by the generated plasma.
A method for coating an electrostatic chuck including a step. The gas containing C, H and F contains at least one of CH ₂ F ₂ gas, CHF ₃ gas, and CHF ₂ gas.
The electrostatic chuck coating method according to claim 4. The step of coating the electrostatic chuck comprises:
Performed before plasma processing the substrate,
The coating method of the electrostatic chuck as described in any one of Claims 1-5. The step of coating the electrostatic chuck comprises:
Executed after dry cleaning the electrostatic chuck with a cleaning gas without placing the substrate on the electrostatic chuck.
The method for coating an electrostatic chuck according to claim 6. Before plasma processing the substrate, a film having a desired thickness distribution is formed on the electrostatic chuck based on a recipe in which a plurality of profiles relating to the thickness of the film formed on the electrostatic chuck are stored in the storage unit. A control unit for controlling supply of a gas containing C and F, or a gas containing C, H and F;
A gas supply source for supplying a gas containing C and F or a gas containing C, H and F in a state where the substrate is not placed on the electrostatic chuck in accordance with control by the control unit,
The control unit controls to coat a part or all of the electrostatic chuck with a film generated by plasma generated from the supplied gas.
Plasma processing equipment. The controller is configured to supply a process gas after coating a part or the whole of the electrostatic chuck with a generated film, and to perform plasma processing on the substrate with plasma generated from the process gas.
The plasma processing apparatus according to claim 8. The control unit supplies a cleaning gas after the substrate is plasma-treated and before a part or all of the electrostatic chuck is coated with a film having a desired thickness distribution. Cleaning the electrostatic chuck with the generated plasma;
The plasma processing apparatus according to claim 9.

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