CN113948360B

CN113948360B - Plasma processing apparatus

Info

Publication number: CN113948360B
Application number: CN202110729723.5A
Authority: CN
Inventors: 渡边大辅; 目黑佑一
Original assignee: Shibaura Machine Co Ltd
Current assignee: Shibaura Machine Co Ltd
Priority date: 2020-07-15
Filing date: 2021-06-29
Publication date: 2024-08-20
Anticipated expiration: 2041-06-29
Also published as: CN113948360A; TW202218098A; TWI794864B

Abstract

The plasma processing apparatus of the present invention processes a substrate, the substrate having: a base; a plurality of devices disposed on one surface of the base; an organic film provided on one surface of the base to cover the plurality of devices; and a resist mask provided on the other surface of the susceptor. The plasma processing apparatus includes an electrostatic chuck disposed on a side of the substrate on which the organic film is formed. The electrostatic chuck has: a dielectric body having a plurality of grooves opened on a surface thereof; an electrode provided inside the dielectric; a film provided on the surface of the dielectric body and covering the openings of the plurality of grooves, the film containing a fluorine resin; and a junction portion provided between the film and the dielectric. When the dimension of the dielectric in the direction parallel to the surface is defined as D1 (mm) and the dimension of the film in the direction parallel to the surface is defined as D2 (mm), the following formula D2 (mm) < D1 (mm) is satisfied.

Description

Plasma processing apparatus

Technical Field

Embodiments of the present invention relate to a plasma processing apparatus.

Background

There is a substrate having a plate-like susceptor such as a wafer, a plurality of devices provided on one surface (hereinafter referred to as a device surface) of the susceptor, and a resist mask formed on the other surface (hereinafter referred to as a back surface) of the susceptor. For example, a resist mask is provided to implant ions into a predetermined region on the back surface of the susceptor.

In such a substrate, after ion implantation, a resist mask formed on the back surface side of the substrate is removed by plasma treatment or the like. In performing plasma processing, a substrate is placed on an electrostatic chuck. At this time, the back surface side of the substrate on which the resist mask to be removed is formed is directed to the plasma processing space, and the device surface side of the substrate is placed on the electrostatic chuck.

However, a plurality of devices are provided on the device side of the substrate. Therefore, in order to protect a plurality of devices, a technology of attaching a glass substrate to a device surface side of a substrate has been proposed. However, if a glass substrate is attached, the substrate is difficult to adhere to the electrostatic chuck. Therefore, a gap is generated between the electrostatic chuck and the substrate, which prevents the electrostatic chuck from cooling the substrate. As a result, the adhesive layer to which the glass substrate is adhered is likely to be degraded by heat during plasma treatment. If the adhesive layer is deteriorated, it may become difficult to peel the glass substrate, or a part of the adhesive layer may remain on the device side of the substrate when the glass substrate is peeled.

In addition, a technique of adhering a thin plate to the device surface side of the substrate has been proposed. Depending on the type of the thin plate, the substrate is more likely to be attracted to the electrostatic chuck than in the case of a glass substrate. But gaps are still easily created between the electrostatic chuck and the substrate. Therefore, it may become difficult to peel off the sheet, as in the case of the glass substrate, or a part of the adhesive layer may remain on the device surface side of the substrate when peeling off the sheet.

In addition, if a glass substrate or a sheet is to be attached to a substrate, a device for attaching the glass substrate or the sheet to the substrate and a device for removing the glass substrate or the sheet from the substrate are required. As a result, the manufacturing cost increases.

Accordingly, a method for protecting devices instead of glass substrates and thin plates is demanded. The present inventors have studied a method of providing an organic film covering a plurality of devices on the device surface side of a substrate instead of a glass substrate and a thin plate. Since the thickness of the organic film can be reduced, the substrate is easily attracted to the electrostatic chuck. Therefore, the organic film is easily cooled by the electrostatic chuck. Thus, the temperature rise of the organic film can be suppressed. The organic film may be formed by an existing technique such as spin coating, or the organic film may be removed by an existing technique such as plasma treatment or wet treatment. Therefore, the formation and removal of the organic film can be handled by existing devices.

However, it was found that when the substrate is separated from the electrostatic chuck after the substrate in a state of being supported by the electrostatic chuck is subjected to plasma treatment, a part of the organic film remains on the surface of the electrostatic chuck. If a material of an organic film is attached to a surface or the like of the electrostatic chuck, a gap is easily generated between the electrostatic chuck and the substrate. Therefore, the cooling of the substrate by the electrostatic chuck is suppressed, or the attraction force of the electrostatic chuck becomes weak.

Here, a technique of coating a modified fluororesin on the surface of an electrostatic chuck has been proposed (for example, refer to patent document 1).

If a layer containing a modified fluororesin is formed on the surface of the electrostatic chuck, the adhesion of the organic film material to the surface of the electrostatic chuck can be suppressed. However, in the case of an electrostatic chuck for cooling a substrate, a groove for flowing a cooling gas needs to be provided on the surface of the electrostatic chuck. If the modified fluororesin is applied to the electrostatic chuck having the grooves on the surface, the grooves are blocked by the modified fluororesin. As a result, it is difficult to cool with the cooling gas.

In this case, an electrostatic chuck having a fluororesin film having an adhesive on only one surface thereof may be considered. However, even at this time, the adhesive or the like for bonding the films may be decomposed by the etchant. That is, the film may be peeled off from the surface of the electrostatic chuck in the vicinity of the peripheral end.

Accordingly, there is a need for a plasma processing apparatus that can prevent peeling from the surface of an electrostatic chuck in the vicinity of the peripheral end of a thin film provided on the electrostatic chuck.

Patent literature

Patent document 1: japanese patent application laid-open No. 2008-91353

Disclosure of Invention

The present invention provides a plasma processing apparatus capable of suppressing peeling from the surface of an electrostatic chuck in the vicinity of the peripheral end of a film provided on the electrostatic chuck.

The plasma processing apparatus according to the embodiment processes a substrate including: a base; a plurality of devices disposed on one surface of the base; an organic film provided on one surface of the base to cover the plurality of devices; and a resist mask provided on the other surface of the susceptor. The plasma processing apparatus includes an electrostatic chuck disposed on a side of the substrate on which the organic film is formed. The electrostatic chuck has: a dielectric body having a plurality of grooves opened on a surface thereof; an electrode provided inside the dielectric; a film provided on the surface of the dielectric body and covering the openings of the plurality of grooves, the film containing a fluorine resin; and a junction portion provided between the film and the dielectric. When the dimension of the dielectric in the direction parallel to the surface is defined as D1 (mm) and the dimension of the film in the direction parallel to the surface is defined as D2 (mm), the following formula D2 (mm) < D1 (mm) is satisfied.

According to an embodiment of the present invention, there is provided a plasma processing apparatus capable of suppressing peeling from a surface of an electrostatic chuck in the vicinity of a peripheral end of a thin film provided on the electrostatic chuck.

Drawings

Fig. 1 is a schematic cross-sectional view of a substrate.

Fig. 2 is a schematic cross-sectional view illustrating the plasma processing apparatus according to the present embodiment.

Fig. 3 is a schematic cross-sectional view for illustrating the structure of the electrostatic chuck.

Fig. 4 is a schematic top view of an electrostatic chuck.

Fig. 5 is a schematic cross-sectional view illustrating an electrostatic chuck according to a comparative example.

Fig. 6 is a schematic cross-sectional view for illustrating the function of the film.

Fig. 7 is a diagram for illustrating the effect of the film.

Symbol description

1-A plasma processing device; 2-chamber; a 3-power supply unit; a 4-power supply unit; 5-a decompression section; 6-a gas supply unit; 7-a placement part; 71-an electrostatic chuck; 71 a-dielectric; 71a 1-groove; 71 b-electrode; 71 c-film; 71c 1-a junction; 75-a cooling gas supply; 100-a substrate; 101-a base; 102-device; 103-resist mask; 104-organic film.

Detailed Description

Hereinafter, embodiments will be described by way of example with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and detailed description thereof is omitted as appropriate.

Substrate 100

First, a substrate 100 processed by the plasma processing apparatus 1 according to the present embodiment is illustrated.

Fig. 1 is a schematic cross-sectional view of a substrate 100.

As shown in fig. 1, a base 101, a device 102, a resist mask 103, and an organic film 104 may be provided on a substrate 100.

The base 101 can be formed as a plate-like body. The susceptor 101 may be a semiconductor substrate such as a wafer. The submount 101 has a back surface 101a and a device surface 101b. A recess 101a1 is provided in the back surface 101a of the base 101. For example, the recess 101a1 can be formed by polishing the back surface 101a of the base 101. The recess 101a1 is not necessarily required. But if the recess 101a1 is provided, the thickness of the region of the base 101 where the plurality of devices 102 are formed can be reduced. Therefore, ions and the like are easily implanted from the back surface 101a side of the susceptor 101 into the region where the device 102 is formed.

A plurality of devices 102 are provided on the device face 101b of the submount 101. The type, number, configuration, etc. of the devices 102 are not intended to be limiting. The device 102 may be, for example, a power transistor with a back electrode, or the like. Since the plurality of devices 102 may be formed by a known semiconductor manufacturing flow, a detailed description of the manufacturing and the like of the plurality of devices 102 is omitted.

The resist mask 103 can be provided on the bottom surface of the recess 101a 1. A resist mask 103 is provided to implant ions or the like into a predetermined region on the bottom surface of the recess 101a 1. For example, the resist mask 103 may be a so-called ion implantation resist mask or the like. Since the resist mask 103 can be formed by a known photolithography method, a detailed description of the manufacturing of the resist mask 103 and the like is omitted.

The substrate 100 processed by the plasma processing apparatus 1 is the substrate 100 after ion implantation. Therefore, a cured layer formed by ion implantation into the resist mask 103 in the ion implantation process exists on the surface of the resist mask 103.

The organic film 104 is provided on the device surface 101b of the base 101 to cover the plurality of devices 102. An organic film 104 is provided for protecting the plurality of devices 102. The thickness of the organic film 104 is not particularly limited. So long as the plurality of devices 102 are covered by the organic film 104. In particular, if considering the ease of removal and the reduction of the removal time after use as a protective film, the thickness of the organic film 104 is preferably as thin as possible.

However, if the thickness of the organic film 104 is too small, the particles 200 may reach the device 102 when the particles 200 described later are pressed against the organic film 104 (for example, see fig. 5 and 6). Generally, the thickness of the device 102 is about several hundred nm, and thus the thickness of the organic film 104 may be, for example, 1 μm or more. More preferably 3 μm or more and 10 μm or less. The organic film 104 may contain a resin such as a photoresist or polyimide, for example. Since the organic film 104 can be formed by a known spin coating method or the like, a detailed description of manufacturing or the like is omitted. Also, the thickness of the organic film 104 is a thickness t (refer to fig. 1) that can cover the thickest portion of the device 102. For example, the thickness t may be confirmed by confirming the cross section of the substrate 100 by TEM or SEM.

Plasma processing apparatus 1

Next, the plasma processing apparatus 1 according to the present embodiment will be described as an example.

The following is an example of a dual-frequency plasma processing apparatus having an inductively coupled electrode at an upper portion and a capacitively coupled electrode at a lower portion. But the plasma generation method is not limited thereto. For example, the plasma processing apparatus may be a plasma processing apparatus using inductively coupled plasma (ICP: inductively Coupled Plasma) or a plasma processing apparatus using capacitively coupled plasma (CCP: CAPACITIVELY COUPLED PLASMA).

However, as described above, a cured layer formed in the ion implantation step exists on the surface of the resist mask 103 which is the removal target. Therefore, the cured layer which is difficult to be chemically removed by radicals or the like is preferably physically removed by ions. In this case, if the dual-frequency plasma processing apparatus is used, the energy of ions introduced into the substrate 100 can be controlled, and thus the cured layer can be easily removed. Therefore, the plasma processing apparatus 1 is preferably a dual-frequency plasma processing apparatus.

Further, since known techniques are applicable to general operations of the plasma processing apparatus 1, flow conditions for removing the resist mask 103, and the like, detailed descriptions thereof are omitted.

Fig. 2 is a schematic cross-sectional view illustrating the plasma processing apparatus 1 according to the present embodiment.

As shown in fig. 2, the plasma processing apparatus 1 may be provided with a chamber 2, a power supply unit 3, a power supply unit 4, a pressure reducing unit 5, a gas supply unit 6, a placing unit 7, and a controller 8.

The controller 8 may have an arithmetic unit such as CPU (Central Processing Unit) and a storage unit such as a memory. The controller 8 may be, for example, a computer. The controller 8 controls the operations of the respective elements provided in the plasma processing apparatus 1 according to a control program stored in the storage unit. Further, since known techniques can be applied to a control program for controlling the operations of the respective elements, detailed description thereof will be omitted.

The chamber 2 has an airtight structure capable of maintaining an atmosphere which is depressurized more than the atmospheric pressure. The chamber 2 has, for example, a substantially cylindrical shape. The chamber 2 is formed of a metal such as an aluminum alloy, for example. The chamber 2 may be grounded.

A hole 2a for carrying in and out the substrate 100 may be provided in a side surface of the chamber 2. In the portion of the chamber 2 where the hole 2a is provided, a load lock chamber (Load Lock Chamber) 21 may be connected. A gate valve 22 can be provided to the load-lock chamber 21. When plasma treatment is performed, the hole 2a is hermetically sealed by the gate valve 22. When the substrate 100 is carried in and out, the holes 2a are communicated with the load-lock chamber 21 through the gate valve 22.

On the top surface of the chamber 2, a window 23 is provided hermetically. The window 23 has a plate shape. The window 23 is permeable to electromagnetic fields. The window 23 can be formed of a material that is difficult to be damaged when plasma processing is performed. The window 23 is formed of a dielectric material such as quartz, for example.

A shielding 24 can be provided inside the chamber 2. When plasma treatment is performed, a reaction product is generated. The reaction product is deposited on the inner wall of the chamber 2, and if the deposited reaction product peels off, it becomes a contaminant such as particles. In addition, if the accumulation amount increases, the processing environment changes, the processing rate changes, and the quality of the product varies. Therefore, cleaning is performed periodically or according to the amount of deposited reaction product. In this case, the inner wall of the chamber 2 may be cleaned, but it takes a lot of labor, time and cost.

Then, a shielding body 24 is provided inside the chamber 2. The shielding member 24 may be formed in a tubular shape, for example, to cover the upper surface of the placement portion 7 and the portion other than the surface of the window 23. The shielding member 24 is formed of, for example, an aluminum alloy, and may be subjected to an aluminum oxide film treatment, a ceramic plating treatment (aluminum oxide, yttrium, or the like) or the like on the surface. If the shielding body 24 is provided, the shielding body 24 may be replaced during cleaning. Thus, the labor and the like required for cleaning can be greatly reduced.

The power supply unit 3 generates plasma P in the inner space of the chamber 2.

The power supply unit 3 includes, for example, an antenna 31, a matcher 32, and a power supply 33.

The antenna 31 may be arranged outside the chamber 2 and on the window 23. The antenna 31 is electrically connected to a power supply 33 via a matcher 32. The antenna 31 may have, for example, a plurality of coils and a plurality of capacitors that generate an electromagnetic field.

The matching unit 32 may include: impedance of the power supply 33 side; and a matching circuit for matching with the impedance of the plasma P side.

The power supply 33 may be a high frequency power supply. The power supply 33 applies high-frequency power having a frequency of, for example, about 100KHz to 100MHz to the antenna 31. At this time, the power supply 33 applies high-frequency power having a frequency (for example, 13.56 MHz) suitable for generating the plasma P to the antenna 31. In addition, the power supply 33 may also change the frequency of the outputted high-frequency power.

The power supply unit 4 is provided for so-called bias control. That is, the power supply unit 4 is provided for controlling the energy of ions introduced into the substrate 100. As described above, a cured layer is formed on the surface of the resist mask 103. The cured layer has high hardness and is difficult to chemically remove by radicals or the like. The plasma processing apparatus 1 according to the present embodiment is provided with a power supply unit 4. Accordingly, the sputtering effect due to the ions is easily generated by controlling the energy of the ions introduced into the substrate 100. Therefore, the cured layer is easily physically removed.

The power supply unit 4 includes, for example, a base 41, a matching unit 42, and a power supply 43.

The susceptor 41 is provided at the bottom of the chamber 2 via an insulating member 41 a. The base 41 is electrically connected to a power supply 43 via a matching unit 42. In addition, an electrostatic chuck 71 can be provided on the base 41. The susceptor 41 serves as an electrode to which high-frequency power is applied from the power supply 43, and also serves as a support base for supporting the electrostatic chuck 71. At this time, the susceptor 41 may have a flow path for flowing cooling water therein, thereby cooling the electrostatic chuck 71. The base 41 is formed of a metal such as an aluminum alloy, for example.

The matching unit 42 is electrically connected between the base 41 and the power supply 43. The matching unit 42 may include a matching circuit for matching between the impedance of the power supply 43 and the impedance of the plasma P.

The power supply 43 may be a high frequency power supply. The power supply 43 applies high-frequency power having a frequency suitable for ion introduction (for example, 13.56MHz or less) to the susceptor 41.

The pressure reducing portion 5 reduces the pressure inside the chamber 2 to a predetermined pressure. For example, when removing the resist mask 103, the pressure in the chamber 2 can be reduced to 100Pa or less by the pressure reducing unit 5.

The pressure reducing portion 5 includes, for example, an on-off valve 51, a pump 52, and a pressure controller 53.

The opening/closing valve 51 is connected to a hole 2b provided on the side surface of the chamber 2. The on-off valve 51 opens and closes a flow path between the chamber 2 and the pump 52. The opening/closing valve 51 may be, for example, a poppet valve.

The pump 52 can be, for example, a turbo molecular pump (TMP: turbo Molecular Pump) or the like.

A pressure controller 53 may be provided between the on-off valve 51 and the pump 52. The pressure controller 53 controls the internal pressure of the chamber 2 to a predetermined pressure based on an output of a vacuum gauge or the like, not shown, that detects the internal pressure of the chamber 2. The pressure controller 53 may be APC (Auto Pressure Controller) or the like, for example.

The gas supply unit 6 supplies the gas G to the inner space of the chamber 2 through a plurality of nozzles 2c provided on the side surface of the chamber 2. For example, the plurality of nozzles 2c can be disposed at substantially equal intervals around the central axis of the chamber 2. In this way, the occurrence of variation in the concentration of the gas G in the region where the plasma P is generated can be suppressed.

The gas supply unit 6 includes, for example, a gas source 61, a gas controller 62, and an on-off valve 63.

The gas source 61 supplies the gas G into the chamber 2 through the gas controller 62 and the on-off valve 63. The gas source 61 may be, for example, a high-pressure bottle or the like containing the gas G. The gas source 61 may be, for example, a factory piping.

The gas G can be excited and activated by the plasma P to generate radicals that react with the resist mask 103 provided on the substrate 100. The gas G may be, for example, oxygen or a mixed gas of oxygen and helium.

A gas controller 62 can be provided between the gas source 61 and the chamber 2. The gas controller 62 controls at least one of the flow rate and the pressure of the gas G supplied from the gas source 61. The gas controller 62 may be MFC (Mass Flow Controller), for example.

The on-off valve 63 can be provided between the gas controller 62 and the chamber 2. The on-off valve 63 controls the start and stop of the supply of the gas G. The on-off valve 63 may be, for example is a two-way solenoid valve, etc. The gas controller 62 may also have a function of an on-off valve 63.

The placement section 7 includes, for example, an electrostatic chuck 71, an insulating ring 72, a mask ring 73, a power supply unit 74, and a cooling gas supply section 75. The placement unit 7 may be provided with a lift pin 76 for transferring the substrate 100 between a not-shown transport device and the electrostatic chuck 71 (see fig. 6, for example).

The side of the substrate 100 on which the organic film 104 is formed is placed on the electrostatic chuck 71. The electrostatic chuck 71 generates an electrostatic force to attract the substrate 100. The electrostatic chuck 71 may use either coulombic force or johnson-raking force. Hereinafter, a case where the electrostatic chuck 71 uses coulomb force will be described as an example.

In addition, when the resist mask 103 is removed, the electrostatic chuck 71 cools the substrate 100 to prevent the temperature of the substrate 100 from becoming too high. That is, the electrostatic chuck 71 has a function of sucking the substrate 100 and a function of cooling the substrate 100.

Fig. 3 is a schematic cross-sectional view for illustrating the structure of the electrostatic chuck 71.

Fig. 4 is a schematic plan view of the electrostatic chuck 71.

As shown in fig. 3, an electrostatic chuck 71 is provided on the base 41.

The electrostatic chuck 71 has, for example, a dielectric 71a, an electrode 71b, and a thin film 71c.

The dielectric 71a has a stepped shape in which the thickness of the central region is greater than the thickness of the peripheral region surrounding the central region. The peripheral edge region of the dielectric 71a can be attached to the base 41 by a coupling member such as a bolt. The dielectric 71a may be made of ceramic such as alumina.

As shown in fig. 3 and 4, a plurality of grooves 71a1 are provided on the surface of the dielectric 71 a. The plurality of grooves 71a1 are open on the surface of the dielectric 71 a. In this case, the plurality of grooves 71a1 can be divided into a plurality of groups, and the grooves 71a1 included in 1 group can be communicated with each other. For example, as shown in fig. 4, the plurality of grooves 71a1 can be divided into 3 groups 71aa to 71ac. The grooves 71a1 included in the group 71aa can be communicated with each other, the grooves 71a1 included in the group 71ab can be communicated with each other, and the grooves 71a1 included in the group 71ac can be communicated with each other.

In addition, a plurality of 1 st holes 71a2 connected to the plurality of grooves 71a1 may be provided in the dielectric 71 a. The 1 st holes 71a2 can be divided into: a gas supply hole 71a2a for supplying a cooling gas G1 to be described later to the plurality of grooves 71a 1; and a gas discharge hole 71a2b for discharging the cooling gas G1 supplied to the plurality of grooves 71a1. The cooling gas supply unit 75 described later can be connected to the gas supply hole 71a2a. An exhaust pipe or the like, not shown, can be connected to the exhaust hole 71a2b. For example, at least 1 air supply hole 71a2a and air discharge hole 71a2b can be connected to the groove 71a1 included in 1 group 71aa (71 ab, 71 ac).

The cooling gas G1 supplied to the plurality of grooves 71a1 through the gas supply holes 71a2a flows through the inside of the plurality of grooves 71a1, and is then discharged to an exhaust pipe or the like, not shown, through the gas discharge holes 71a2 b. That is, the plurality of grooves 71a1 serve as flow paths for the cooling gas G1 supplied from the cooling gas supply unit 75.

In addition, a plurality of holes 71a3 (corresponding to one example of the 2 nd hole) penetrating in the thickness direction may be provided in the dielectric 71 a. The plurality of holes 71a3 may be provided with a lift pin 76 (see fig. 6, for example).

In addition, a groove 71a1 connected to the hole 71a3, and an air supply hole 71a2a and an air discharge hole 71a2b connected to the groove 71a1 may be provided. A part of the cooling gas G1 supplied to the groove 71a1 through the gas supply hole 71a2a flows through the inside of the groove 71a1 and then diffuses in the hole 71a 3. Therefore, a part of the cooling gas G1 directly contacts the portion of the organic film 104 opposite to the hole 71a 3. Thus, the cooling efficiency can be improved.

The electrode 71b is plate-shaped and is provided inside the dielectric 71 a. The electrode 71b may be of either a monopolar type or a bipolar type. For example, in the case of a bipolar type, 2 electrodes 71b may be arranged on the same plane. The electrode 71b is formed of, for example, a metal such as tungsten or molybdenum.

The thin film 71c is in a film shape and is provided on the surface of the dielectric 71 a. The film 71c covers the openings of the plurality of grooves 71a 1. The film 71c may contain, for example, a fluororesin. A joint portion 71c1 is provided between the film 71c and the dielectric 71 a. The joint 71c1 may be a layer formed by curing an adhesive, an adhesive tape, or the like.

At this time, if the joint portion 71c1 intrudes into the groove 71a1, the flow of the cooling gas may be blocked. If the joint portion 71c1 is an adhesive tape, the penetration of the joint portion 71c1 into the inside of the groove 71a1 is easily suppressed. In addition, the adhesion work of the film 71c and the peeling work of the film 71c are facilitated.

In addition, if the total of the thickness of the joint portion 71c1 and the thickness of the thin film 71c is too large, the force of sucking the substrate 100 may be weakened or the cooling of the substrate 100 may be suppressed. Therefore, the total of the thickness of the joint portion 71c1 and the thickness of the film 71c is preferably 100 μm or less.

In addition, if the irregularities on the surface of the thin film 71c are excessively large, the gap between the thin film 71c and the substrate 100 (the organic film 104) becomes large. Therefore, the force of sucking the substrate 100 becomes weak or the cooling of the substrate 100 by the electrostatic chuck 71 is suppressed.

As described above, since the thickness of the joint portion 71c1 and the thickness of the thin film 71c are small, the irregularities on the surface of the dielectric 71a are transferred to the surface of the thin film 71 c. Therefore, the arithmetic average roughness Ra of the surface of the dielectric 71a is preferably 0.3 μm or less. In this way, irregularities on the surface of the thin film 71c can be reduced.

Fig. 5 is a schematic cross-sectional view illustrating an electrostatic chuck 171 according to a comparative example.

The electrostatic chuck 171 is provided with the dielectric 71a and the electrode 71b, but is not provided with the thin film 71c. Therefore, the organic film 104 of the substrate 100 directly contacts the surface of the dielectric 71 a.

As described above, the dielectric 71a is formed of ceramic such as alumina. Therefore, when the substrate 100 is held by the electrostatic chuck 171 without the thin film 71c, the substrate 100 is brought into contact with the dielectric 71a of the electrostatic chuck. Since the substrate 100 is in contact with the dielectric 71a of the electrostatic chuck 171, fine particles including ceramics may be generated. In addition, the substrate 100 and the dielectric 71a expand due to the heat of the plasma. Since the expansion coefficients of the substrate 100 and the dielectric 71a are different, friction may occur even when expansion occurs. Accordingly, fine particles 200 including ceramics or the like may be attached to the surface of the dielectric 71 a. If the substrate 100 is adsorbed to the electrostatic chuck 171 in a state where the particles 200 are attached to the surface of the dielectric 71a, as shown in fig. 5, the particles 200 present on the surface of the dielectric 71a enter the organic film 104.

In addition, the groove 71a1 of the dielectric 71a is usually formed by cutting. Therefore, burrs may be formed in the grooves 71a1. Since the cooling gas G1 flows in the groove 71a1, the burrs may be peeled off from the groove 71a1 during the plasma treatment and become particles 200. The cooling gas supply unit 75 described below supplies the cooling gas G1 through a filter not shown. However, the particles 200 that have leaked through the filter or the particles 200 that have passed through the filter and then exist between the paths of the grooves 71a1 may be included in the cooling gas G1. Therefore, in the electrostatic chuck 171 without the thin film 71c, the particles 200 existing in the groove 71a1 may enter the organic film 104 due to the cooling gas G1.

In addition, a hole 71a3 for providing the lift pin 76 may be provided in the dielectric 71 a. When the cooling gas is supplied to the hole 71a3, the particles 200 existing on the inner wall of the hole 71a3 may enter the organic film 104 due to the cooling gas.

At this time, if the particle diameter of the particles 200 is larger than the distance between the end of the device 102 and the surface of the organic film 104, the particles 200 entering the inside of the organic film 104 reach the device 102. Thus, damage to the device 102 may occur.

Fig. 6 is a schematic cross-sectional view for illustrating the function of the film 71 c.

As described above, the thin film 71c is provided on the surface of the dielectric 71 a. Therefore, as shown in fig. 6, even if particles 200 are attached to the surface of the dielectric 71a, the particles 200 can be prevented from entering the inside of the organic film 104 by the thin film 71 c.

In addition, as described above, the film 71c covers the openings of the plurality of grooves 71a 1. Therefore, the particles 200 existing on the inner wall of the groove 71a1 can be prevented from entering the organic film 104 by the cooling gas.

Fig. 7 is a diagram for illustrating the effect of the thin film 71 c.

"A1" and "A2" in fig. 7 indicate the number of particles 200 adhering to the surface of the organic film 104 in the electrostatic chuck 171 according to the comparative example. That is, the number of particles 200 adhering to the surface of the organic film 104 when the thin film 71c is not provided is shown. "A2" is the case where the particle size of the particle 200 is 5 μm or more. That is, "A2" represents the number of particles 200 having a size that can cause the aforementioned degree of damage to the device 102. "A1" is the case where the particle size of the particle 200 is 0.3 μm or more and less than 5. Mu.m. That is, "A1" represents the number of particles 200 of almost the entire size except for particles 200 having a size to which the device 102 can be damaged.

"B1" represents the number of particles 200 adhering to the surface of the organic film 104 in the electrostatic chuck 71 according to the present embodiment. That is, the number of particles 200 adhering to the surface of the organic film 104 when the thin film 71c is provided is shown. "B1" is the case where the particle size of the particle 200 is 0.3 μm or more and less than 5. Mu.m. That is, "B1" represents the number of particles 200 of almost the entire size except for particles 200 having a size to which the device 102 can be damaged.

As can be seen from fig. 7, if the openings of the plurality of grooves 71a1 are covered with the thin film 71c, the number of particles 200 of almost the entire size adhering to the surface of the organic film 104 can be reduced. That is, the particles 200 adhering to the organic film 104 can be suppressed. In addition, particles 200 having a size that can cause damage to the device 102 can be prevented from adhering to the surface of the organic film 104. That is, particles having a size of 5 μm or more, which can cause damage to the device 102, can be prevented from being generated.

In order to confirm that the organic film 104 was formed on the surface of the aluminum substrate, the inventors conducted experiments on whether or not the indentation due to the particles 200 was generated on the surface of the substrate. The indentation means a flaw or a depression having a planar dimension of 5 μm×5 μm or more.

In the case of the electrostatic chuck 171 (in the case where the film 71c is not provided), 67 indentations are generated.

In the case of the electrostatic chuck 71 (in the case where the film 71c is provided), no indentation is generated. This means that if the thin film 71c is provided on the surface of the electrostatic chuck 71, the device 102 can be suppressed from being damaged.

On the other hand, it was found that if the substrate 100 was separated from the electrostatic chuck 71 after the plasma treatment was performed, a part of the organic film 104 of the substrate 100 remained on the surface of the electrostatic chuck 71 (on the thin film 71 c). The film 71c at this time is formed of polyimide.

If a part of the organic film 104 adheres to the thin film 71c provided on the surface of the dielectric 71a, the adhesion of the electrostatic chuck 71 to the substrate 100 is inhibited, the cooling of the substrate 100 by the electrostatic chuck 71 is suppressed, or the suction force of the electrostatic chuck 71 is weakened.

The inventors believe that this is because the organic film 104 has no adhesive layer unlike the glass substrate or the thin plate. That is, the inventors believe that this is because the adhesion between the organic film 104 and the device 102, the device face 101b is weaker than the adhesion between the organic film 104 and the surface of the thin film 71 c.

In the case of the present embodiment, since the thin film 71c contains a fluororesin, the material of the organic film 104 is difficult to adhere. In addition, when the resist mask 103 is removed, decomposition and deterioration of the thin film 71c due to plasma are less likely to occur.

In addition, the etchant may intrude from a gap between the mask ring 73 and the substrate 100, which will be described later. At this time, as shown in fig. 3, when the dimension of the dielectric 71a in the direction parallel to the surface is D1 (mm) and the dimension of the thin film 71c in the direction parallel to the surface is D2 (mm), it is preferable that "D2 (mm) < D1 (mm)". In this way, the peripheral end surface of the joint portion 71c1 is provided at a position closer to the center side of the dielectric 71a than the peripheral end surface of the dielectric 71 a. Accordingly, the etchant that intrudes from the gap between the mask ring 73 and the substrate 100 is hard to reach the vicinity of the peripheral end of the joint portion 71c 1. Therefore, the vicinity of the peripheral end of the joint portion 71c1 is prevented from being decomposed, and the vicinity of the peripheral end of the thin film 71c is prevented from being peeled off from the surface of the dielectric 71 a. According to the knowledge obtained by the present inventors, if the distance between the peripheral end face of the dielectric 71a and the peripheral end face of the thin film 71c is L (mm), it is preferable that "0.5 mm.ltoreq.L.ltoreq.5 mm". In this way, peeling from the surface of the dielectric 71a in the vicinity of the peripheral end of the thin film 71c can be effectively suppressed. The etchant is an active species such as ions and radicals generated from the gas G excited and activated by the plasma P.

Here, the organic film 104 is the same type as the resist mask 103 to be removed. Therefore, when the resist mask 103 is removed, there is a possibility that an exposed portion of the organic film 104 (for example, a peripheral end surface of the organic film 104) is decomposed by the etchant penetrating from the gap between the mask ring 73 and the substrate 100. If the material of the decomposed organic film 104 adheres to the surface of the thin film 71c, the material of the adhered organic film 104 may be deteriorated by heat or the like to be hardened. Further, as the number of processed substrates 100 increases, the amount of adhesion may increase with time. If there is an adhesion substance having a high hardness or an adhesion substance having a large size on the surface of the electrostatic chuck 71 (film 71 c), the adhesion substance can interfere with the substrate 100 even when the substrate 100 is placed on the electrostatic chuck 71. If the adhering substance interferes with the substrate 100, there is a possibility that the substrate 100 may be damaged, the force of sucking the substrate 100 may be weakened, or the temperature of the substrate 100 may be unevenly distributed in the surface.

Then, in the electrostatic chuck 71 according to the present embodiment, "D2 (mm) < D3 (mm)" is obtained when the dimension of the organic film 104 in the direction parallel to the surface is D3. In this way, when the substrate 100 is adsorbed, the thin film 71c is covered with the organic film 104, so that even if decomposition occurs near the peripheral end of the organic film 104, adhesion of the material of the organic film 104 to the surface of the thin film 71c can be suppressed. Therefore, damage to the substrate 100 due to the material of the attached organic film 104, weakening of the force of adsorption to the substrate 100, and uneven distribution in the surface of the substrate 100 temperature can be suppressed.

As described above, particles 200 including ceramics or the like are generated by the contact of the electrostatic chuck with the substrate 100. However, as described above, the surface of the dielectric 71a is polished in order to reduce the irregularities on the surface of the dielectric 71a. Therefore, it is considered that particles 200 including ceramics or the like are also generated when the dielectric 71a is formed. It is considered that particles 200 including ceramics or the like generated when the dielectric 71a is formed adhere to the surface of the dielectric 71a. Particles 200 including ceramics or the like adhering to the dielectric 71a during formation cannot be completely removed by ordinary cleaning, and some of them continue to adhere to the dielectric 71a.

Regarding the problem of the adhesion of the particles 200 including ceramics or the like to the dielectric 71a, the present inventors have dealt with by covering the surface of the dielectric 71a and the groove 71a1 with the thin film 71 c.

At this time, if "D2 (mm) < D3 (mm)" is made in a state where the thin film 71c does not cover the vicinity of the peripheral edge of the dielectric 71a, the particles 200 including ceramics or the like may adhere to the vicinity of the peripheral edge of the organic film 104.

In the present embodiment, the vicinity of the peripheral end of the organic film 104 does not contact the electrostatic chuck 71. Therefore, even if particles 200 of 5 μm or more are attached near the peripheral edge of the organic film 104, it is considered that the particles 200 of 5 μm or more do not enter the inside of the organic film 104. However, the organic film 104 may contact the electrostatic chuck of the transfer arm or other device during the transfer of the substrate 100 after the plasma treatment and when the treatment is performed on the back surface 101a of the substrate 100 in the next step. That is, if particles 200 of 5 μm or more, which may damage the device 102, are attached near the peripheral end of the organic film 104, there is a possibility that damage may occur to the device. However, as shown in fig. 7, in this embodiment, particles 200 of 5 μm or more, which can cause damage to the device 102, can be prevented from adhering to the organic film 104.

Even if the thin film 71c does not cover the vicinity of the peripheral edge of the dielectric 71a, particles 200 of 5 μm or more, which can damage the device 102, do not adhere to the organic film 104, and the mechanism is not necessarily clear. But can be considered as follows.

By attaching the thin film 71c to the surface of the dielectric 71a, a distance is generated between the particles 200 including ceramics or the like attached near the peripheral end of the dielectric 71a and the organic film 104 of the substrate 100. Therefore, it is considered that the particles 200 can be prevented from adhering to the organic film 104.

Next, other elements provided in the placement unit 7 will be described with reference to fig. 2.

As shown in fig. 2, the insulating ring 72 is cylindrical and is provided at the bottom of the chamber 2. The insulating ring 72 covers the side surface of the base 41. The insulating ring 72 is formed of a dielectric material such as quartz, for example.

The mask ring 73 is cylindrical and is provided in a peripheral region of the dielectric 71a of the electrostatic chuck 71. The mask ring 73 encloses a central region of the electrostatic chuck 71. By disposing the mask ring 73 in this manner, the vicinity of the peripheral edge of the dielectric 71a can be prevented from being exposed to the etchant. Therefore, the dielectric 71a is provided in the peripheral region, and the damage of the connecting member by the corrosive agent can be suppressed.

The mask ring 73 is formed of a dielectric material such as quartz, for example.

In addition, if the mask ring 73 is provided, it is possible to suppress the etchant from reaching the peripheral end face of the organic film 104 when the resist mask 103 is removed. Therefore, the adhesion of the material of the organic film 104 to the surface of the electrostatic chuck 71 due to the decomposition of the peripheral end face of the organic film 104 can be suppressed.

The power supply unit 74 includes, for example, a dc power supply 74a and a changeover switch 74b. The dc power supply 74a is electrically connected to the electrode 71b of the electrostatic chuck 71. When a voltage is applied to the electrode 71b by the dc power supply 74a, electric charges are generated on the surface of the electrode 71b on the substrate 100 side. Accordingly, an electrostatic force is generated between the electrode 71b and the substrate 100, and the substrate 100 is attracted to the electrostatic chuck 71 by the generated electrostatic force.

The switch 74b is electrically connected between the dc power supply 74a and the electrode 71b of the electrostatic chuck 71, and switches between adsorption and desorption of the substrate 100.

The cooling gas supply unit 75 supplies the cooling gas G1 to the groove 71a1 through the gas supply hole 71a2a provided in the dielectric 71 a. That is, the cooling gas supply unit 75 supplies the cooling gas into the plurality of grooves 71a1 covered with the thin film 71 c.

The cooling gas supply unit 75 includes, for example, a gas source 75a, a gas controller 75b, and an on-off valve 75c. The gas source 75a may be, for example, a high-pressure bottle or the like in which the cooling gas G1 is contained. The gas source 75a may be, for example, a factory piping. The cooling gas G1 may be helium gas or the like, for example.

A gas controller 75b can be disposed between the gas source 75a and the electrostatic chuck 71. The gas controller 75b controls at least one of the flow rate and the pressure of the cooling gas G1 supplied from the gas source 75 a. The gas controller 75b may be, for example, an MFC or the like.

For example, when removing the resist mask 103, the gas controller 75b can control at least one of the flow rate and the pressure of the cooling gas so that the surface temperature of the substrate 100 becomes 80 ℃ or lower. For example, the gas controller 75b can set the surface temperature of the substrate 100 to 80 ℃ or lower by setting the temperature of the electrostatic chuck 71 to 45 ℃ or lower. For example, the gas controller 75b can control the supply flow rate of the cooling gas G1 so that the detected value of the pressure of the space defined by the thin film 71c and the plurality of grooves 71a1, which is detected by a pressure gauge not shown, becomes 400Pa to 2000Pa, whereby the surface temperature of the substrate 100 can be set to 80 ℃.

The on-off valve 75c can be provided between the gas controller 75b and the electrostatic chuck 71. The on-off valve 75c controls the start and stop of the supply of the cooling gas G1. The on-off valve 75c may be, for example is a two-way solenoid valve, etc. The gas controller 75b may also have a function of opening and closing the valve 75 c.

Here, as described above, the film 71c covers the openings of the plurality of grooves 71a 1. Therefore, the cooling gas G1 supplied to the plurality of grooves 71a1 cools the substrate 100 through the thin film 71 c. In this case, in order to enhance the cooling effect, the temperature of the cooling gas G1 is preferably not higher than normal temperature (for example, not higher than 25 ℃).

If the cooling gas G1 is supplied to the space divided by the thin film 71c and the plurality of grooves 71a1, the cooling gas G1 directly contacts the thin film 71c. Therefore, the heat transfer efficiency is better than when the film 71c is cooled by the cooling gas G1 via the dielectric 71 a.

For example, the cooling gas supply unit 75 may further include a cooler 75d for cooling the supplied cooling gas G1. The cooler 75d may be, for example, a heat exchanger or the like that cools the cooling gas G1 so that the temperature of the cooling gas G1 becomes-20 ℃ or lower. The liquefied cooling gas G1 may be gasified to be the cooling gas G1. In this way, even if the cooler 75d is not provided, the cooling gas G1 at-20 ℃ or lower can be supplied to the electrostatic chuck 71.

In the present embodiment, the air supply hole 71a2a and the air discharge hole 71a2b can be separated. In this way, particles 200 having a particle diameter that may damage the device 102 can be prevented from being generated, and the flow of the cooling gas G1 can be formed in the space partitioned by the thin film 71c and the plurality of grooves 71a 1. Therefore, the cooling efficiency improves.

The plasma processing apparatus 1 according to the present embodiment is particularly suitable for plasma processing of the substrate 100 having the recess 101a1 in the back surface 101a of the susceptor 101.

When the thickness of the susceptor 101 is the substrate 100 which is thin as a whole, deflection occurs due to the low rigidity of the substrate 100. Therefore, a glass substrate or sheet having a certain thickness is used to supplement rigidity.

In the substrate 100 of the present embodiment, the outer peripheral portion of the susceptor 101 is thick. Therefore, the substrate 100 of the present embodiment has higher rigidity than the substrate 100 in which the thickness of the susceptor 101 is thinner as a whole. Thus, the substrate 100 of the present embodiment does not need to use a glass substrate or a thin plate to supplement rigidity. Therefore, as long as the organic film 104 has a thickness that can protect the device 102. That is, the thickness of the organic film 104 of the substrate 100 of the present embodiment can be made smaller than that of a glass substrate or a thin plate.

The thickness of the organic film 104 is very thin compared to a glass substrate or sheet. Therefore, the force of the electrostatic chuck 71 for sucking the substrate 100 of the present embodiment is larger than that in the case of sucking the substrate 100 protected by the glass substrate or the thin plate. Accordingly, even if the pressure in the space defined by the thin film 71c and the plurality of grooves 71a1 is set to be higher than the pressure at the time of suction of the substrate 100 protected by the glass substrate or the thin plate, the substrate 100 of the present embodiment is not separated from the electrostatic chuck 71. That is, even if the cooling gas G1 having a higher pressure than before is supplied to the space divided by the film 71c and the plurality of grooves 71a1, the film 71c does not expand due to the pressure of the cooling gas G1. As described above, the cooling gas G1 can be supplied to the space partitioned by the thin film 71c and the plurality of grooves 71a1 at a higher pressure than before. Therefore, the cooling efficiency of the substrate 100 of the present embodiment is better than that of the substrate 100 protected by a glass substrate or a thin plate.

In the present embodiment, the thickness of the organic film 104 can be 3 μm or more and 10 μm or less. By setting the thickness of the organic film 104 within the above range, the cooling gas G1 can be supplied at a higher pressure than before as described above. Therefore, the cooling efficiency is better than that of the substrate 100 protected by the glass substrate or the thin plate. In addition, the thickness of the organic film 104 of the substrate 100 in which the device 102 is protected by the organic film is small. Therefore, heat transfer to the susceptor 101 is preferable. Thus, the cooling efficiency of the substrate 100 protected by the organic film 104 is better for the device 102 than for the substrate 100 protected by a glass substrate or sheet.

The embodiments are exemplified above. However, the present invention is not limited to the above description.

In the foregoing embodiments, if the features of the present invention are provided, those skilled in the art can appropriately implement addition, deletion, design change, addition of steps, omission, or condition change of the constituent elements, and the like, and the present invention is also included in the scope of the present invention.

The elements of the embodiments described above may be combined as long as the technology is technically feasible, and the combination of these techniques is also included in the scope of the present invention as long as the features of the present invention are included.

For example, the removal of the resist mask 103 is described as an example of the plasma treatment, but the present invention is not limited thereto. For example, the process of etching the rear surface 101a of the susceptor 101 of the substrate 100 and the process of forming a metal film or an insulating film on the rear surface 101a of the susceptor 101 are also included in the plasma process.

For example, an opening may be provided in a portion of the film 71c opposite to the air supply hole 71a2 a. In this way, the cooling efficiency of the substrate 100 is improved.

For example, the 1 st hole 71a2 is divided into the air supply hole 71a2a and the air discharge hole 71a2b, but may be used without being divided. For example, in the plasma processing, the gas G may be continuously supplied from the 1 st hole 71a2, and the gas may be exhausted from the 1 st hole 71a2 after the plasma processing is completed.

Claims

1. A plasma processing apparatus for processing a substrate, the substrate comprising: a base; a plurality of devices disposed on one surface of the base; an organic film provided on one surface of the base to cover the plurality of devices; and a resist mask provided on the other surface of the base, characterized in that,

An electrostatic chuck disposed on a side of the substrate on which the organic film is formed,

The electrostatic chuck has: a dielectric body having a plurality of grooves opened on a surface thereof;

An electrode provided inside the dielectric;

A film provided on the surface of the dielectric body and covering the openings of the plurality of grooves, the film containing a fluorine resin;

And a junction portion provided between the film and the dielectric body,

When the dimension of the dielectric in the direction parallel to the surface is defined as D1 (mm) and the dimension of the film in the direction parallel to the surface is defined as D2 (mm), the following formula D2 (mm) < D1 (mm) is satisfied.

2. The plasma processing apparatus according to claim 1, wherein a thickness of the organic film is 5 μm or more and 10 μm or less.

3. The plasma processing apparatus according to claim 1 or 2, wherein when a dimension of the organic film in a direction parallel to a surface is taken as D3, the following formula D2 (mm) < D3 (mm) is satisfied.

4. The plasma processing apparatus according to any one of claims 1 to 3, wherein when a distance between a peripheral end face of the dielectric and a peripheral end face of the thin film is L, the following formula 0.5 mm.ltoreq.L.ltoreq.5 mm is satisfied.

5. The plasma processing apparatus according to any one of claims 1 to 4, wherein a total of a thickness of the joint portion and a thickness of the thin film is 100 μm or less.

6. The plasma processing apparatus according to any one of claims 1 to 5, further comprising a cooling gas supply unit configured to supply a cooling gas into the plurality of grooves whose openings are covered with the thin film.