JP2023131599A - Substrate placement table, substrate processing device, and method for manufacturing substrate placement table - Google Patents

Abstract

To equalize electric fields formed on a surface of a substrate placement table that includes an attraction electrode for attracting a substrate and in which a gas supply hole is formed.SOLUTION: In a substrate placement table that holds a substrate by electrostatic attraction force, a dielectric layer is laminated on an upper side of a base, a top face of thereof serving as a placement table for the substrate, and an attraction electrode that generates the electrostatic attraction force is buried in the dielectric layer. A gas supply port for supplying a gas toward the substrate penetrates the base, the attraction electrode and the dielectric layer and opens in the placement surface, with a through-hole formed in the attraction electrode provided so as to enclose the gas supply port by being isolated via an isolation part. A shield layer composed of a conductor is disposed by being electrically isolated from the attraction electrode, and is formed so as to cover at least a portion of the isolation part in a plan view, and to enclose the gas supply port.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a substrate mounting table, a substrate processing apparatus, and a method of manufacturing a substrate mounting table.

In the manufacturing process of FPDs (Flat Panel Displays) and semiconductor devices, substrate processing such as etching is sometimes performed with the substrate (glass substrate or semiconductor wafer) fixed on the substrate mounting table using electrostatic adsorption force. be.

Patent Document 1 describes an electrostatic adsorption device in which a hole for heat transfer gas is formed so as to penetrate an electrode layer for electrostatic adsorption, and a cutout is formed on the inner wall surface of the hole so that the electrode layer is not exposed. The equipment is described.

Japanese Patent Application Publication No. 2005-136350

The present disclosure provides a technique for uniformizing the electric field formed on the surface of a substrate mounting table that includes an adsorption electrode for adsorbing a substrate and has gas supply holes formed therein.

The present disclosure provides a substrate mounting table that holds a substrate using electrostatic adsorption force,
The base and
a dielectric layer laminated on the upper side of the base, the upper surface of which serves as a mounting surface for the substrate;
an adsorption electrode embedded in the dielectric layer and generating the electrostatic adsorption force;
A gas supply hole that penetrates the base, the suction electrode, and the dielectric layer and opens to the mounting surface, and is configured to supply gas toward the substrate placed on the mounting surface. and,
a through hole formed in the adsorption electrode as a region for passing the gas supply hole through, and provided so as to surround the gas supply hole while being separated from it via a separation part;
Disposed inside or on the dielectric layer so as to be electrically isolated from the adsorption electrode, covering at least a portion of the separation part when viewed in plan from a direction perpendicular to the placement surface, and supplying the gas. The substrate mounting table includes a shield layer made of a conductor and formed to surround a hole.

According to the present disclosure, it is possible to equalize the electric field formed on the surface of the substrate mounting table, which includes a suction electrode for suctioning a substrate and has gas supply holes formed therein.

FIG. 1 is a longitudinal side view of the substrate processing apparatus of the present disclosure. FIG. 3 is a plan view of a configuration example of the substrate mounting table. FIG. 2 is an enlarged longitudinal cross-sectional side view of a first configuration example of an electrostatic chuck. FIG. 7 is an enlarged longitudinal cross-sectional side view of a second configuration example of the electrostatic chuck. It is an electric field simulation result based on a conventional configuration example. It is an electric field simulation result based on an Example. It is an electric field simulation result based on a 1st reference example. It is an electric field simulation result based on a 2nd reference example.

<Substrate processing equipment>
Hereinafter, the overall configuration of a substrate processing apparatus 1 including a substrate mounting table 2 according to the present disclosure will be described with reference to FIGS. 1 and 2.
For example, the substrate processing apparatus 1 supplies a plasma processing gas to a film to be etched on the surface of a rectangular glass substrate (hereinafter simply referred to as "substrate") G for FPD to perform etching processing. It is configured as an etching processing apparatus.

As shown in FIG. 1, the substrate processing apparatus 1 includes a grounded prismatic cylindrical container body 10 made of a conductive material, and a top plate portion 11 that airtightly closes an opening on the top surface of the container body 10. These container body 10 and top plate portion 11 correspond to the processing container of this example, and a processing space 100 for substrates G is formed inside thereof. A side wall of the container body 10 is provided with a loading/unloading port 101 and a gate valve 102 for loading/unloading the substrate G.

A substrate mounting table 2 for mounting a substrate G is provided on the lower side of the processing space 100 so as to face the top plate section 11 . The substrate mounting table 2 includes a base 21 made of a conductive metal material, such as aluminum. An electrostatic chuck 22 for holding the substrate G by electrostatic attraction is provided on the upper surface of the base 21. The electrostatic chuck 22 can be switched between adsorbing and holding the substrate G and releasing it by supplying and disconnecting power from a DC power source (not shown). A detailed configuration example of the electrostatic chuck 22 will be described later with reference to FIGS. 3 and 4. The base 21 is housed within an insulator frame 24 and installed on the bottom surface of the container body 10 via the insulator frame 24.

Further, the substrate mounting table 2 has a plurality of elevating and lowering devices, for example, four or more elevating devices, for transferring the substrate G to and from an external substrate transport mechanism (not shown) that has entered the processing space 100 via the loading/unloading port 101. A pin 23 is provided. Each lifting pin 23 is provided so as to vertically penetrate through the base 21 and the bottom plate of the container body 10, and the lower end portions of these lifting pins 23 are connected to a lifting mechanism 230 provided outside the container body 10. There is. A plurality of hoisting passages 231 are formed in the base 21 and form a path through which the lifting pins 23 move up and down. It is open towards the enemy (Fig. 2).

A second high frequency power source 252 is connected to the substrate mounting table 2 (base 21) via a matching box 251. The second high-frequency power supply 252 supplies bias high-frequency power, for example, high-frequency power with a frequency of 3.2 MHz, to the substrate mounting table 2 . Ions in the plasma generated within the processing space 100 can be drawn into the substrate G by the self-bias generated by this high-frequency power for bias. The substrate mounting table 2 functions as a lower electrode for self-bias generation.

Further, in the substrate mounting table 2, in order to control the temperature of the substrate G, a temperature adjustment mechanism including a coolant flow path and the like is provided (not shown). The temperature adjustment mechanism may include a heating section in addition to the refrigerant flow path. Further, the coolant channel is not limited to a coolant for cooling, but may be a temperature regulating medium for adjusting the temperature of the substrate G to an appropriate temperature.

On the other hand, since the inside of the container body 10 (processing space 100) where the etching process is performed is in a vacuum pressure atmosphere, the substrate G and the substrate G are separated by a small gap between the top surface of the electrostatic chuck 22 and the back surface of the substrate G. The mounting table 2 is insulated, making it difficult to control the temperature of the substrate G with high precision. Therefore, the substrate mounting table 2 of this example includes a mechanism for supplying heat transfer gas between the electrostatic chuck 22 (substrate mounting table 2) and the substrate G. By supplying the heat transfer gas, heat exchange is easily performed between the upper surface (mounting surface) of the electrostatic chuck 22 and the substrate G, and the temperature of the substrate G can be controlled with high precision.

A mounting table gas diffusion chamber 211 is formed in the base 21 of the substrate mounting table 2 as a supply mechanism for the heat transfer gas. A plurality of gas supply holes 212 are formed on the upper surface side of the mounting table gas diffusion chamber 211, passing through the base 21 and the electrostatic chuck 22 in the vertical direction.

The lower end of each gas supply hole 212 communicates with the mounting table gas diffusion chamber 211, while the upper end of these gas supply holes 212 communicates within the plane of the electrostatic chuck 22 (the mounting surface of the substrate mounting table 2). The openings are distributed throughout the area (Figure 2). Although shown in simplified form in FIGS. 1 and 2, a large number of gas supply holes 212 are formed in the substrate mounting table 2, for example, about 100 or more, or 2000 or more. With this configuration, the gas in the mounting table gas diffusion chamber 211 can be dispersed and discharged from the upper surface of the electrostatic chuck 22.

A mounting table gas supply line 213 is connected to the lower surface side of the mounting table gas diffusion chamber 211 . This mounting table gas supply line 213 is connected to a heat transfer gas supply source (not shown) that supplies, for example, helium (He) gas as a heat transfer gas.

Further, as shown in FIG. 1, an exhaust port 103 is formed at the bottom of the container body 10, and a vacuum exhaust section 12 including a vacuum pump or the like is connected to the exhaust port 103. Furthermore, in order to ensure that the gas supplied into the processing space 100 flows uniformly toward the periphery of the substrate mounting table 2, it is necessary to A rectifying plate 104 having a large number of small holes may be placed between the wall surface and the rectifying plate 104.

As shown in FIG. 1, a shower head 31 for supplying processing gas and the like to the processing space 100 is provided on the lower surface side of the top plate section 11. The shower head 31 includes a shower gas diffusion chamber 311. A large number of shower gas discharge holes 312 are formed on the lower surface side of the shower head 31, and the gas diffused into the shower gas diffusion chamber 311 is distributed and supplied toward the processing space 100 via these shower gas discharge holes 312. Ru.

Further, a shower gas supply line 32 communicating with a shower gas diffusion chamber 311 is connected to the upper surface side of the shower head 31 . An etching gas supply source (not shown) for supplying etching gas, which is a processing gas, is connected to the upstream side of the shower gas supply line 32 . The shower head 31, the shower gas supply line 32, and the etching gas supply source correspond to the processing gas supply section of this example.

Further, as shown in FIG. 1, a recess is formed on the lower surface of the top plate part 11, and a space within the recess surrounded by the upper surface of the shower head 31 and the lower surface of the top plate part 11 is used to arrange the high frequency antenna 5. This serves as an antenna room 50 for The shower head 31 constitutes a metal window made of, for example, aluminum.
For example, the high frequency antenna 5 is formed in a spiral shape so as to circulate along the circumferential direction of the shower head 31 in a plane corresponding to the shower head 31.

A first high frequency power source 512 is connected to each high frequency antenna 5 via a matching box 511. For example, high frequency power of 13.56 MHz is supplied to each high frequency antenna 5 from a first high frequency power supply 512 via a matching box 511. Thereby, the processing gas and static elimination gas supplied into the processing space 100 through the metal window are turned into plasma by inductive coupling, and desired etching processing and static elimination processing can be performed.

Here, the high frequency antenna 5, the shower head 31 which is a metal window, the matching box 511, and the first high frequency power source 512 correspond to a plasma forming section for forming plasma of the processing gas and the static elimination gas.
Note that the configuration of the plasma forming section is not limited to the case where it includes the high frequency antenna 5 for forming inductively coupled plasma and a metal window. For example, a dielectric window may be provided instead of the metal window, and the shower head may be provided on a beam member that supports the dielectric window from below. Further, a configuration may be adopted in which capacitively coupled plasma is formed between the substrate mounting table 2 and the metal shower head 31.

<Control unit 6>
As shown in FIG. 1, the substrate processing apparatus 1 includes a control section 6. As shown in FIG. The control unit 6 is constituted by a computer including a storage unit storing programs, a memory, and a CPU. The program includes instructions (steps) for outputting control signals from the control section 6 to each section of the substrate processing apparatus 1, and for carrying in and out of the substrate G and executing processing. The program is stored in a storage unit of the computer, such as a flexible disk, compact disk, hard disk, MO (magneto-optical disk), non-volatile memory, etc., and is read from this storage unit and installed in the control unit 6.

<Plasma treatment>
Processing of the substrate G using the substrate processing apparatus 1 described above will be briefly described.
First, the gate valve 102 is opened, and the substrate G is loaded into the processing space 100 via the loading/unloading port 101 by a transport mechanism outside the processing space 100 . Next, the substrate G is placed on the mounting surface of the substrate mounting table 2 via the lifting pins 23 and fixed by the electrostatic chuck 22, while the transfer mechanism is evacuated from the processing space 100 and the gate valve is closed. 102 is closed.

Thereafter, an etching gas is supplied from an etching gas supply source (not shown) into the processing space 100 through the shower gas diffusion chamber 311, while the processing space 100 is evacuated by the vacuum evacuation section 12, and the processing space is The inside of 100 is adjusted to a preset vacuum pressure atmosphere. Further, the temperature of the substrate G is controlled by a temperature control mechanism (not shown), and a heat transfer gas is supplied to the back side of the substrate G from each gas supply hole 212.

Next, high frequency power is supplied from the high frequency power source 512 to the high frequency antenna 5, thereby converting the processing gas supplied into the processing space 100 through the shower head 31, which is a metal window, into plasma by inductive coupling. More specifically, the high-frequency antenna 5 generates an induced current that circulates between the upper and lower surfaces of the metal window, and the induced electric field that flows through the lower surface of the metal window generates an induced electric field in the processing space 100. Gas is turned into plasma by inductive coupling. At this time, it is preferable that the metal window is divided into a plurality of parts. Ions in the plasma are drawn toward the substrate G by the bias high frequency power supplied from the high frequency power supply 252 to the substrate mounting table 2, and the etching process on the substrate G is performed.

After performing the etching process on the substrate G for a preset time in this manner, the supply of each high frequency power and the temperature adjustment of the substrate G are stopped, and the supply of etching gas and heat transfer gas is also stopped. Then, the substrate G is carried out from the processing space 100 in the opposite procedure to the procedure used when carrying it in.

<Issue during etching process>
In the substrate processing apparatus 1 having the configuration described above, as described above, the upper surface of the substrate mounting table 2 (the surface on which the substrate G is placed) has heat transfer to the back surface of the substrate G as shown in FIG. A large number of gas supply holes 212 are opened to supply gas. The inventors discovered that when etching processing, which is plasma processing, is performed using the electrostatic chuck 22 having such a configuration, the etching processing occurs between the region where the gas supply hole 212 is open and the other region. It has been found that differences in the results (unevenness in processing) may occur.

As a result of examining the above-mentioned issues, it was found that the strength of the electric field above the area where the gas supply hole 212 is open varies greatly compared to the electric field around it, which is a contributing factor to the formation of processing unevenness. It was discovered that this may have an impact. We have also found a method that can make the electric field uniform between the opening area of the gas supply hole 212 and its surroundings. The detailed configuration of the electrostatic chuck 22 provided with means for uniformizing the electric field will be described below with reference to FIGS. 3 to 6.

<Detailed structure of electrostatic chuck 22>
3 and 4 show examples of the structure of the electrostatic chuck 22 in which shield layers 224a and 224b are arranged to equalize the electric field in the opening region of the gas supply hole 212. Since the configurations of the electrostatic chucks 22 are common to each other except for the arrangement positions of the shield layers 224a and 224b, the detailed configuration of the electrostatic chucks 22 will be described first with reference to FIG. 3.

The electrostatic chuck 22 includes a main body layer 221 (dielectric layer) made of a dielectric and laminated on the upper side of the base 21 described above, and a suction electrode 222 embedded in the main body layer 221. For example, the main body layer 221 is constituted by a thermally sprayed film formed by thermally spraying alumina onto the upper surface of the base 21 (step of laminating dielectric layers). The main body layer 221 may be directly laminated on the upper surface of the base 21. In addition, when the temperature of the substrate mounting table 2 is adjusted by the temperature adjustment mechanism, if the difference in the coefficient of thermal expansion between the base 21 and the main body layer 221 is large, an intermediate thermal A buffering metal film having a coefficient of expansion may also be provided. In this case, the main body layer 221 may be laminated on the upper surface of the buffer metal film.

The adsorption electrode 222 is made of a conductive metal film. When embedding the adsorption electrode 222 in the main body layer 221, an example of a method is to divide the thermal spraying of the main body layer 221 into two stages. That is, after forming a lower layer sprayed film with a thickness of about several hundred μm on the upper side of the base 21, the adsorption electrode 222 with a thickness of about several tens of μm is arranged on the upper surface thereof. Thereafter, an upper sprayed film with a thickness of about several hundred μm is formed on the lower sprayed film and the upper surface of the adsorption electrode 222. As a result, it is possible to configure the electrostatic chuck 22 in which the attracting electrode 222 is embedded in the main body layer 221 (step of forming the attracting electrode).

A finishing layer 223 may be provided on the uppermost layer side of the electrostatic chuck 22. The finishing layer 223 is formed on the upper surface of the main body layer 221 in order to adjust the surface roughness of the surface on which the substrate G is placed. The finishing layer 223 is composed of a sprayed alumina film having a thickness of, for example, several tens of micrometers. The finishing layer 223 is included in the dielectric layer of this embodiment together with the main body layer 221.

The gas supply hole 212 is formed to penetrate the above-described base 21, the adsorption electrode 222, and the main body layer 221, and open to the mounting surface of the electrostatic chuck 22. For example, the gas supply hole 212 is formed by drilling a hole in the base 21 with a drill or the like, and forming the adsorption electrode 222 and the main body layer 221 by thermal spraying while forming a through hole communicating with the hole (gas supply hole ). At the position where the gas supply hole 212 penetrates the adsorption electrode 222, the gas supply hole 212 is configured as a flow path with a diameter of less than 1 mm, preferably within a range of 0.4 to 0.6 mm.

Further, from the viewpoint of suppressing the occurrence of abnormal discharge, it is preferable that the metal forming the suction electrode 222 is not exposed on the inner wall surface of the gas supply hole 212 at the position where the gas supply hole 212 penetrates the suction electrode 222. . Therefore, as shown in FIG. 3, a through hole 222a having an opening diameter larger than that of the gas supply hole 212 is provided in the adsorption electrode 222 as a region for passing the gas supply hole 212 therethrough. As described above, when the diameter of the gas supply hole 212 is less than 1 mm, the diameter φ of the through hole 222a can be, for example, 3 mm within the range of 1.5 to 5 mm. The through holes 222a can be formed by placing a mask at the formation location of the through holes 222a and performing thermal spraying during molding of the main body layer 221 (step of forming the through holes).

The inner wall surface of the gas supply hole 212 formed with this configuration is surrounded by a spaced apart part from the inner peripheral edge of the through hole 222a.

5(a) and 6(a) show the bias voltage supplied to the substrate mounting table 2 (lower electrode) in the processing space 100 shown in FIG. 1 for the substrate mounting table 2 having the configuration described above. This is an example of the configuration of a simulation model for determining the distribution of the strength of an electric field formed by high-frequency power. In the substrate mounting table 2, when high-frequency power for bias is supplied from the second high-frequency power supply 252 to the base 21, and DC voltage (3 kv) for electrostatic adsorption is applied to the adsorption electrode 222, This simulates the electric field generated by the

FIG. 5(a) corresponds to a conventional configuration example in which a shield layer 224b, which will be described later, is not provided, and FIG. 6(a) is a simulation model corresponding to an embodiment in which a shield layer 224b is provided. The horizontal axes in FIGS. 5A and 6A indicate horizontal coordinate axes, and the vertical axes indicate vertical coordinate axes. In the simulation model, the physical properties of aluminum were used for the base 21, alumina was used for the main body layer 221, the finishing layer 223, and tungsten was used for the adsorption electrode 222. Further, the thickness of the main body layer 221 on the lower side than the adsorption electrode 222 is 300 μm, the total thickness of the upper main body layer 221 and the finishing layer 223 is 220 μm, the thickness of the shield layers 224a and 224b is 50 μm, and the gas supply hole The diameter of the hole 212 was 0.5 mm, and the diameter of the through hole 222a was 3 mm.

5(b) and 6(b) show the intensity of the electric field in the direction along the plate surface of the substrate G at the height position of the surface of the substrate G held on the mounting surface of the electrostatic chuck 22. It is a graph showing changes. The horizontal axis represents the horizontal coordinate axis corresponding to FIGS. 5(a) and 6(a), and the vertical axis represents the relative strength of the electric field. The horizontal broken lines in FIGS. 5(b) and 6(b) indicate the maximum/minimum electric field strength in both simulations.

First, the simulation results shown in FIGS. 5(a) and 5(b) corresponding to the conventional configuration example will be confirmed. According to the simulation results, the electric field once becomes strong near a position corresponding to the inner peripheral edge of the through hole 222a, and then the intensity of the electric field rapidly decreases toward the inside of the through hole 222a.

Here, as schematically shown in FIGS. 3 and 4, in the main body layer 221, since the adsorption electrode 222 is not arranged inside the through hole 222a, the dielectric portion is formed thicker. There is. The capacitance of the dielectric is expressed by the following equation (1), and the capacitance decreases in the region of the main body layer 221 where the dielectric is thick (inside the through hole 222a).
C=(ε ₀・ε _s・S)/d…(1)
(However, C: Capacitance of target area, ε ₀ : Vacuum permittivity, ε _s : Relative permittivity of dielectric, S: Area, d: Thickness of dielectric)
Further, since the region where the gas supply hole 212 is formed is also a space where the heat transfer gas flows, the capacitance decreases.

The electric field formed on the upper surface side of the electrostatic chuck 22 has a proportional relationship with the capacitance of the main body layer 221, as shown in equation (2) below. Therefore, in a region where the capacitance decreases, the strength of the electric field formed on the upper surface side also decreases.
E=C・V/(S・ε ₀ )…(2)
(However, E: electric field formed on the upper surface side of the target region, V: voltage applied between the lower electrode and the processing space 100)

As described above, the etching process by the substrate processing apparatus 1 proceeds by the action of ions of the etching gas turned into plasma. At this time, if an electric field distribution with a large intensity difference is formed on the surface of the substrate G as shown in FIG. It can be inferred that this may be a contributing factor to the occurrence of processing unevenness at positions corresponding to the areas.

As discussed above, the occurrence of processing unevenness in the area where the gas supply holes 212 are formed is due to the through holes 222a being provided in the adsorption electrode 222 and the dielectric portion of the main body layer 221 being thick. This is considered to be one of the factors. In this case, a possible method for making the electric field around the gas supply hole 212 more uniform is to reduce the opening diameter of the through hole 222a and bring the inner peripheral edge of the through hole 222a closer to the inner wall surface of the through hole 222a. If the separation between the inner circumferential edge of the through hole 222a and the inner wall surface of the through hole 222a is made as small as possible, the area of the region where the capacitance is small will be reduced, and the electric field formed around the gas supply hole 212 will be reduced. It has the potential to contribute to uniformity.

However, when forming the gas supply hole 212, there is a limit to reducing the opening diameter of the through hole 222a when considering processing tolerances, etc., and it is difficult to make the electric field uniform to the extent that processing unevenness can be reduced. may not be possible. Further, if the inner peripheral edge of the through hole 222a is brought too close to the inner wall surface of the through hole 222a, there is a possibility that dielectric breakdown will occur, leading to the occurrence of abnormal discharge.

Therefore, in each embodiment shown in FIGS. 3 and 4, shield layers 224a and 224b are provided which are electrically isolated from the main body layer 221.
FIG. 3 shows an example in which a shield layer 224a is arranged on the upper surface side of the finishing layer 223. In this example, the adsorption electrode 222 is embedded in the main body layer 221 located below the shield layer 224a. Due to this configuration, the shield layer 224a is provided at a different position from the suction electrode 222 and above the suction electrode 222 with respect to the position along the direction perpendicular to the mounting surface. That is, the shield layer 224a and the adsorption electrode 222 are provided at different heights.

In this case, the shield layer 224a is formed by forming the main body layer 221 and the finishing layer 223 with a thermal spray film, and then pasting a metal seal on the surface of the finishing layer 223 or printing a metal film with a 3D printer. (step of forming a shield layer). In this case, the step of forming the gas supply hole may be performed together with the step of forming the shield layer. Further, the shield layer 224a may be formed by thermal spraying using a mask that exposes the portion where the shield layer 224a is to be formed. In this case, the gas supply hole 212 may be closed with a plug or the like so that the thermal spray material does not enter the gas supply hole 212.

Further, FIG. 4 shows an example in which a shield layer 224b is arranged inside the main body layer 221. In this example as well, the shield layer 224b is provided at a position different from the adsorption electrode 222 and above the adsorption electrode 222 in the direction perpendicular to the mounting surface of the substrate G. That is, the shield layer 224b and the adsorption electrode 222 are provided at different heights. This arrangement has the effect of keeping the mounting surface flat when viewed from the processing space 100 side.

When arranging the shield layer 224b above the attracting electrode 222, an example of a method is to divide the formation of the main body layer 221 above the attracting electrode 222 into multiple stages. That is, after forming the lower sprayed film and arranging the adsorption electrode 222, the first stage sprayed film is formed on its upper surface. After that, a shield layer 224b is formed using a metal seal or a 3D printer (step of forming a shield layer). Then, a second stage sprayed film is formed around the shield layer 224b, and finally a finishing layer 223 is formed. In this case as well, the step of forming the gas supply hole may be performed together with the step of forming the shield layer. Further, the shield layer 224a may be formed by thermal spraying using a mask that exposes the portion where the shield layer 224a is to be formed. In this case, the gas supply hole 212 may be closed with a plug or the like so that the thermal spray material does not enter the gas supply hole 212.

The shield layers 224a and 224b are made of a conductive material, for example, a metal material such as copper, aluminum, stainless steel, titanium, or tungsten. As shown in the simulation results described later, by providing the shield layers 224a and 224b made of a conductor in the separated part made of a dielectric material, the electric field around the region where the gas supply hole 212 is formed is significantly uniformized.

In FIGS. 3 and 4, the positional relationship between the outer circumferential edges of the shield layers 224a and 224b and the inner circumferential edge of the through hole 222a is shown by broken lines. As can be seen from the positional relationship shown by these broken lines, the shield layers 224a and 224b are located between the inner wall surface of the gas supply hole 212 and the inner wall of the through hole 222a when viewed from the direction perpendicular to the mounting surface of the substrate G. It is formed so as to cover the entire part separated from the peripheral surface.

However, it is not an essential requirement that the shield layers 224a and 224b be formed so as to cover the entire separation section. By forming the shield layers 224a and 224b to cover at least a portion of the separation part and to surround the gas supply hole 212, the electric field on the surface of the substrate G is made uniform in the region where the gas supply hole 212 is formed. You can obtain the effect of Note that, for example, the outer peripheral edges of the shield layers 224a, 224b may protrude above the adsorption electrode 222, but in this case, the shield layers 224a, 224b and the adsorption electrode 222 may overlap vertically. There is a possibility that the electrostatic adsorption force of the electrostatic chuck 22 may decrease depending on the size of the area in the state.

6(a) and 6(b) show a simulation model corresponding to the embodiment of FIG. 4 in which a shield layer 224b is provided in the dielectric layer (main layer 221, finishing layer 223), and the electric field distribution of the simulation result. It is. The simulation model in FIG. 6(a) has the same configuration as in FIG. 5(a) except that a shield layer 224b is provided. In the simulation model of FIG. 6A, the shield layer 224b uses the physical properties of tungsten, has a thickness of 50 μm, and a diameter φ of 3 mm.

As shown in the simulation results of FIG. 6(b), by arranging the shield layer 224b within the dielectric layer (main layer 221, finishing layer 223), compared to the conventional configuration example shown in FIG. 5(b), , the increase in electric field strength near the position corresponding to the inner peripheral edge of the through hole 222a is moderated. Furthermore, the amount of decrease in electric field strength toward the inside of the through hole 222a is also significantly reduced. As a result, the electric field around the gas supply hole 212 can be made much more uniform than in the conventional configuration in which the shield layer 224b is not provided.
This effect is the same in the embodiment shown in FIG. 3 in which the shield layer 224a is provided on the upper surface side of the dielectric layer (main layer 221, finishing layer 223).

By providing the electrostatic chuck 22 in which the shield layers 224a and 224b illustrated in FIGS. 3 and 4 are arranged at the formation position of each gas supply hole 212 to the substrate processing apparatus 1, processing unevenness in the etching process can be prevented. It is thought that this can be reduced.

As reference examples, FIGS. 7(a), (b), and 8(a), (b) show the case of a conventional configuration example in which the shield layer 224b is not arranged for the opening of the hoistway 231 of the hoisting pin 23, and The simulation results of the electric field distribution are shown in the case where the shield layer 224b is disposed.

Regarding these simulation models, the constituent materials and thickness settings of each member (base 21, adsorption electrode 222, main body layer 221, shield layer 224b, etc.) are explained in FIGS. 5(a) and 6(a). Similar to the example. On the other hand, the diameter of the lifting pin 23 was 4.5 mm, the diameter of the hoistway 231 was 5.4 mm, the opening diameter of the through hole 222a, and the diameter of the shield layer 224b were 9.8 mm. Further, the simulation was performed under the conditions that the lifting pin 23 was at the same potential as that of the lifting pin 21, and the tip of the lifting pin 23 was placed at a position 0.05 mm below the substrate G placed on the mounting surface.

Comparing the simulation results in FIG. 7(b) and FIG. 8(b), it is found that the maximum/minimum electric field strength is both shifted upward by providing the shield layer 224b. On the other hand, no significant change was observed in the difference between the maximum and minimum intensity, and no significant effect of uniformizing the electric field could be confirmed.

The simulation results in FIGS. 7(b) and 8(b) relate to the hoistway 231 in which the elevating pins 23 are arranged, and the configurations of the simulation models are also different. Therefore, it is not possible to directly evaluate the effect of a change in the diameter of the gas supply hole 212 on the arrangement of the shield layers 224a, 244b. However, even when the shield layers 224a and 244b are arranged, it is suggested that as the opening diameter of the gas supply hole 212 is increased, the effect of uniformizing the electric field may decrease. It can be said that there are.
In this regard, as described above, it has been confirmed that the arrangement of the shield layers 224a and 224b has a sufficient effect of uniformizing the electric field when the diameter of the gas supply hole 212 is less than 1 mm.

<Effect>
According to the present disclosure, the shield layers 224a and 224b are provided so as to cover the separation between the inner wall surface of the gas supply hole 212 and the inner peripheral edge of the through hole 222a when viewed from the side of the mounting surface of the substrate G. . With this configuration, the electric field formed on the surface of the substrate mounting table 2 in which the gas supply holes 212 are formed can be made uniform.

Here, the substrate processing apparatus 1 using the electrostatic chuck 22 in which the shield layers 224a and 224b are arranged around the gas supply hole 212 is not limited to the etching process described above. For example, the electrostatic chuck 22 of the present disclosure may be provided in a substrate processing apparatus that performs a film formation process of forming a film on the surface of the substrate G by converting a source gas or a reaction gas reacted with the source gas into plasma. Further, the electrostatic chuck 22 of the present disclosure is suitably used in a substrate processing apparatus that generates plasma, but can also be applied to a processing apparatus that does not convert various processing gases into plasma. If a change in the electric field around the gas supply hole 212 affects the in-plane uniformity of substrate processing, the electrostatic charge of the present disclosure may be A chuck 22 may also be used.

In addition, the target substrate to be held by electrostatic adsorption force and processed with a processing gas using the substrate mounting table 2 equipped with the electrostatic chuck 22 of the present disclosure is not limited to the example of a glass substrate. For example, the substrate mounting table 2 of the present disclosure may be provided in a substrate processing apparatus that processes semiconductor wafers.

The embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. The embodiments described above may be omitted, replaced, or modified in various forms without departing from the scope and spirit of the appended claims.

G Substrate 2 Substrate mounting table 21 Base 212 Gas supply hole 22 Electrostatic chuck 221 Main body layer 222 Adsorption electrode 222a Through hole 223 Finishing layer 224a, 224b
shield layer

Claims (8)

A substrate mounting table that holds a substrate using electrostatic adsorption force,
The base and
a dielectric layer laminated on the upper side of the base, the upper surface of which serves as a mounting surface for the substrate;
an adsorption electrode embedded in the dielectric layer and generating the electrostatic adsorption force;
A gas supply hole that penetrates the base, the suction electrode, and the dielectric layer and opens to the mounting surface, and is configured to supply gas toward the substrate placed on the mounting surface. and,
a through hole formed in the adsorption electrode as a region for passing the gas supply hole through, and provided so as to surround the gas supply hole while being separated from it via a separation part;
Disposed inside or on the dielectric layer so as to be electrically isolated from the adsorption electrode, covering at least a portion of the separation part when viewed in plan from a direction perpendicular to the placement surface, and supplying the gas. A substrate mounting table comprising a shield layer made of a conductor and formed to surround a hole. When the shield layer is disposed inside the dielectric layer, the shield layer is disposed at a position different from the adsorption electrode layer in a direction perpendicular to the placement surface. , The substrate mounting table according to claim 1. The substrate mounting table according to claim 2, wherein the shield layer is formed to cover the entire separation section. The substrate mounting table according to any one of claims 1 to 3, wherein the gas supply hole has a diameter of less than 1 mm at a portion where the gas supply hole penetrates the dielectric layer. A temperature control mechanism is provided to adjust the temperature of the substrate via the mounting surface, and the gas supply hole is provided with a temperature control mechanism for exchanging heat between the substrate placed on the mounting surface and the mounting surface. The substrate mounting stand according to any one of claims 1 to 4, wherein a heat transfer gas is supplied for the substrate mounting table. A substrate processing apparatus that processes a substrate,
a processing container in which substrate processing is performed;
a processing gas supply unit that supplies processing gas into the processing container;
A substrate processing apparatus comprising: the mounting table according to any one of claims 1 to 5, provided in the processing container. The substrate processing apparatus according to claim 6, further comprising a plasma forming section that turns the processing gas into plasma. A method for manufacturing a substrate mounting table that holds a substrate using electrostatic adsorption force, the method comprising:
laminating a dielectric layer on the upper side of the base, the upper surface of which serves as a mounting surface for the substrate;
forming an adsorption electrode that generates the electrostatic adsorption force so as to be embedded in the dielectric layer;
A gas supply hole that penetrates the base, the suction electrode, and the dielectric layer and opens to the mounting surface, and is configured to supply gas toward the substrate placed on the mounting surface. a step of forming;
When carrying out the step of forming an adsorption electrode, a through-hole is formed in the adsorption electrode as a region for passing the gas supply hole through, and is provided so as to surround the gas supply hole while being separated through a separation part. a step of forming;
Disposed inside or on the dielectric layer so as to be electrically isolated from the adsorption electrode, covering at least a portion of the separation part when viewed in plan from a direction perpendicular to the placement surface, and supplying the gas. A method for manufacturing a substrate mounting table, including the step of forming a shield layer made of a conductor so as to surround the hole.

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