JP3121524B2 - Etching equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an etching apparatus for etching a substrate to be processed, for example, an insulating film of a semiconductor wafer.

[0002]

2. Description of the Related Art Conventionally, for example, in a semiconductor manufacturing process, an etching apparatus has been used as an apparatus for etching an insulating film on a surface of a semiconductor wafer (hereinafter, referred to as a "wafer") to form a contact hole. Among them, a so-called parallel plate type etching apparatus in which electrodes are arranged above and below the processing chamber has advantages such as excellent uniformity, processing of a large-diameter wafer, and the like, and also has an apparatus configuration. Many are used because they are relatively simple.

[0003] The conventional general parallel plate type etching apparatus is, as well known in, for example, Japanese Patent Application Laid-Open No. 62-69620, in which electrodes are provided at upper and lower sides of a processing chamber so as to face each other. A wafer serving as a substrate is placed on a lower electrode, and an etching gas is introduced into the processing chamber, and high-frequency power is supplied to the lower electrode to generate plasma between the upper and lower electrodes, which is generated by dissociation of the etching gas. The insulating film on the wafer is etched by the etchant ions.

[0004] By the way, this type of insulating film etching processing requires finer processing, higher processing speed, and uniform processing with the increase in the degree of integration of semiconductor devices. It is also required to increase the density of the generated plasma. In this regard, in the plasma processing apparatus disclosed in Japanese Patent Application Laid-Open No. 62-69620, in order to prevent the generated plasma from being diffused and concentrated between the electrodes, the outer peripheral portion of at least one of the electrodes facing each other is required. And a narrowly spaced structure in which the distance between the insulator and another electrode or other insulator is 70% or less of the distance between the opposing electrodes is provided. The diffusion of the generated area is prevented.

[0005]

However, the technology disclosed in Japanese Patent Application Laid-Open No. 62-69620 is a
It is intended to manufacture DRAM of about 6k to 1M, and has a highly integrated device such as today, for example, a 64M DRA.
It is no longer suitable for the production of M. That is, in order to perform faster and finer etching, it is necessary to further reduce the pressure in the processing chamber to increase the plasma density. However, in the conventional technique, 0.5 Torr to 3.0 Ton is used.
It is assumed that the degree of pressure reduction is about rr, and it is practically difficult to prevent the diffusion of the plasma region at a higher degree of vacuum by using only the technique disclosed in the publication, and an improvement in the etching rate is expected. Can not. Of course, it is desired that this type of etching be performed uniformly on the wafer. However, as in the above-described conventional technique, an insulator is simply disposed, and this insulator and another electrode or another insulator are disposed. If the distance between the electrodes is set to be smaller than the distance between the electrodes, the plasma density will be higher in the place close to the narrow distance between the insulators than in the center of the electrodes. This may affect the uniformity of Also, to prevent plasma diffusion,
If the interval formed by the insulator is simply narrowed, the exhaust of the supplied etching gas or the like is delayed, and the intended etching may not be performed.

The present invention has been made in view of such a point, and in order to perform fine etching at a high speed which can cope with the manufacture of a 64M DRAM, the pressure in the processing chamber is reduced to, for example, 10 mTorr to 100 mTorr. Even if the pressure is reduced, the generated plasma is efficiently confined between the electrodes to realize a high etching rate by high-density plasma, and to provide an etching apparatus capable of performing more uniform etching processing to solve the above problem. That is its purpose. Another object of the present invention is not to unduly suppress gas exhaustion in preventing plasma diffusion so that desired etching can be performed without increasing a gas flow rate of an etching gas or the like.

[0007]

In order to achieve the above object, an etching apparatus according to claim 1 has an upper electrode and a lower electrode facing each other in a processing chamber capable of reducing pressure, and supplies the upper electrode and the lower electrode by supplying high frequency power. In an etching apparatus configured to generate plasma between an upper electrode and a lower electrode to etch a substrate to be processed on the lower electrode, an upper insulator is provided around the upper electrode, and a periphery of the lower electrode is provided. , A conductive first annular body and a second annular body made of an insulator located on the outer periphery of the first annular body are arranged,
With the inner peripheral edge of the annular protrusion formed on the lower surface of the upper insulator
The outer peripheral edge is set so as to be located above the second annular body.
The narrowest distance between the annular protrusion and the second annular body is set to be smaller than the distance between the upper electrode and the lower electrode.

[0008]

[0009] The etching apparatus of claim 2, wherein
2. The etching apparatus according to claim 1, wherein an outer peripheral portion of the first annular member and an inner peripheral portion of the second annular member are overlapped, and an outer peripheral edge of the protrusion is formed of the second annular member. Upward
And the inner peripheral edge of the protrusion is set at a position corresponding to the overlapping portion between the outer peripheral portion of the first annular member and the inner peripheral portion of the second annular member. Things. The etching apparatus according to any one of claims 1 to 3, wherein
High frequency power is applied to both the upper and lower electrodes
And a conductive first
The annular body is made of silicon as claimed in claim 4.
I can plan.

[0010]

In the etching apparatus of the first aspect, a first conductive ring is arranged around the lower electrode, and a second annular body made of an insulator is further arranged around the first ring.
Between the upper and lower electrodes and the portion of the upper insulator closer to the inner periphery of the annular protrusion , the plasma generated between the upper and lower electrodes is reduced to the second annular shape. Diffusion between the body and the portion of the protrusion near the inner periphery is suppressed. Then, the ions in the so-called confined plasma are effectively incident on the substrate to be processed on the lower electrode by the first annular body. Therefore, fine etching is performed on the substrate to be processed under high-density plasma. Since the inner peripheral edge and the outer peripheral edge of the protruding portion are located above the second annular body located on the outer periphery of the first annular body, the operation and effect of the first annular body are not impaired. In addition, it is possible to prevent the density of the peripheral portion of the substrate to be processed from being unduly increased due to the above-described plasma confining action.

[0011] etching apparatus of claim 1 has a configuration further noted gas conductance.
That is, the upper insulator forming a narrower gap than the upper and lower electrodes
The inner peripheral edge and the outer peripheral edge of the portion near the inner periphery of the annular protrusion are the second
Is set above the annular body , the radial length (width) of the portion near the inner periphery of this projection is shorter than the radial length (width) of the second annular body. I have. Accordingly, the gas conductance at the time of evacuation from the space (processing space) between the upper and lower electrodes is improved by that amount, and the flow rate of the processing gas such as an etching gas supplied between the upper and lower electrodes to be turned into plasma can be suppressed without reducing the flow rate. Can be trapped efficiently.

In the etching apparatus according to the second aspect, the outer peripheral portion of the conductive first annular body and the inner peripheral portion of the insulator second annular body are superposed. In the portion, the plasma is diluted as compared with the space between the upper and lower electrodes. Therefore,
Since the inner peripheral edge of the annular protrusion forming the narrowest space in the upper insulator constituting the plasma confining means is located in this portion, the inner peripheral edge is located more than in the cases of the first and second embodiments. The plasma diffusion can be prevented at a place closer to the substrate to be processed, and the plasma density around the substrate to be processed does not become higher than the center. Moreover, the protrusion
Since the outer peripheral edge of the protruding portion is located above the second annular body, the gas conductance is good as in the case of the second aspect.

In the etching apparatus according to the present invention, if one of the electrodes is supplied with power of a relatively high frequency and the other electrode is supplied with power of a lower frequency, a higher frequency power is supplied. In this case, the plasma is generated and maintained, and the incident speed of ions dissociated at that time to the substrate to be processed can be controlled at a lower frequency.
Therefore, in the case of the third aspect, it is possible to adopt a configuration that makes it easy to control the etching .

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 schematically shows a cross section of an etching apparatus 1 according to the present embodiment. A cylindrical processing vessel 3 made of aluminum or the like, which can be hermetically sealed and is anodized.
And the processing vessel 3 itself is grounded via a ground wire 4. An insulating support plate 5 made of ceramic or the like is provided at the bottom of the processing chamber 2, and a substrate to be processed, for example, a semiconductor wafer (hereinafter, referred to as a “wafer”) W having a diameter of 8 inches is provided on the insulating support plate 5. A susceptor 6 having a substantially cylindrical shape and constituting a lower electrode for mounting the susceptor is accommodated in a vertically movable manner.

The susceptor 6 is supported by an elevating shaft 7 which penetrates the insulating support plate 5 and the bottom of the processing container 3. The elevating shaft 7 is connected to a drive motor 8 installed outside the processing container 3. It can move up and down freely. Therefore, the operation of the drive motor 8 causes the susceptor 6 to move.
Are movable up and down as shown by the reciprocating arrows in FIG. In order to secure the airtightness of the processing chamber 2, an airtight member that can expand and contract, for example, a bellows 9 is provided between the susceptor 6 and the insulating support plate 5 so as to surround the outside of the elevating shaft 7. I have.

The susceptor 6 is made of aluminum whose surface is oxidized, and has temperature control means therein.
Heating means such as a ceramic heater (not shown)
Also, a coolant circulation path (not shown) for circulating the coolant with an external coolant source (not shown) is provided, and the wafer W on the susceptor 6 can be maintained at a predetermined temperature. It is configured as follows. Further, the temperature is automatically controlled by a temperature sensor (not shown) and a temperature control mechanism (not shown).

On the susceptor 6, an electrostatic chuck 11 for holding the wafer W by suction is provided.
As shown in detail in FIG. 2, the electrostatic chuck 11 is formed by, for example, forming a conductive thin film 12 on a polyimide resin 13.
When a voltage is applied to the thin film 12 from a high-voltage DC power supply 14 provided outside the processing chamber 3, the wafer W is held by the electrostatic chuck 11 by the Coulomb force. The upper surface is held by suction. Of course, the configuration may be such that the peripheral edge of the wafer W is pressed by a mechanical clamp and the wafer W is held on the susceptor 6 without using such an electrostatic chuck.

At the periphery of the susceptor 6, an inner focus ring 21 having a substantially annular plane and constituting a first annular body is provided so as to surround the electrostatic chuck 11. The inner focus ring 21 is made of conductive silicon, and has stepped portions 21a and 21b which are respectively lowered by one step on the inner peripheral side and the outer peripheral side upper surface. The upper surface of the inner peripheral side stepped portion 21a is The upper surface of the step 21a is set so as to be flush with the upper surface of the electrostatic chuck 11, and the lower surface of the peripheral portion of the wafer W held by the electrostatic chuck 11 is placed thereon. The inner focus ring 21 has a function of effectively causing ions in the plasma to be incident on the wafer W.

An outer focus ring 22 having a substantially annular flat surface is provided on the outer periphery of the inner focus ring 21. The outer focus ring 22 is made of insulating quartz, and its inner peripheral portion 22a is provided so as to be mounted on the step portion 21b of the inner focus ring 21. Therefore, the outer periphery of the inner focus ring 21 and the inner periphery of the outer focus ring 22 are overlapped at the portions of the step portions 21b and the inner peripheral portion 22a. The central portion 21c of the inner focus ring 21 and the upper surface of the outer focus ring 22 are set to be flush. Further, an outer peripheral upper edge portion 22b of the outer focus ring 22 is formed in a curved shape convex outward, so that gas is smoothly discharged without stagnant. The outer focus ring 22 has a plasma diffusion preventing function together with a shield ring 42 described later.

As shown in FIG. 2, an insulating baffle plate 25 is disposed around the susceptor 6 via a quartz insulating ring 23 and a fluororesin insulating ring 24. 25 is a quartz support 26
Is fixed by means such as bolts. Accordingly, the baffle plate 25 also moves up and down as the susceptor 6 moves up and down. The baffle plate 25 has a large number of through holes 25a, and has a function of uniformly discharging gas.

A diffusion member 32 for introducing an etching gas or other gas into the processing chamber 2 is provided above the processing chamber 2 via an insulating member 31 with respect to the processing chamber 3. . As shown in FIG. 2, the diffusion member 32 has a hollow structure in which flat portions 32a are arranged in a plurality of upper and lower stages in parallel, and a large number of diffusion holes 33 are formed in each flat portion 32a. Have been. A gas inlet 34 is provided at the center of the diffusion member 32, and valves 35, 36,
An etching gas, for example, CF ₄ gas from a processing gas supply source 38 is introduced into the processing chamber 2 through the introduction port 34 and the diffusion hole 33 of the diffusion member 32 via a mass flow controller 37 for adjusting a flow rate. It has become.

Below the diffusion member 32, an upper electrode 41 is supported by the insulating member 31 so as to face the susceptor 6. The upper electrode 41 is made of conductive silicon, and has a large number of discharge ports 41 a for uniformly discharging the gas introduced by the diffusion member 32 to the wafer W on the susceptor 6. The shield ring 42 made of quartz constituting the upper insulator is arranged around the upper electrode 41 such that the inner periphery of the upper side is fixed to the insulating member 31.

The shield ring 42 has an annular projection 43 formed on the lower surface near the inner periphery. The inner periphery 43 a of the projection 43 is formed on the outer periphery of the inner focus ring 21 and the outer focus ring 22. It is set so as to be located at a position corresponding to a portion where the inner periphery overlaps, that is, above a portion where the step portion 21b of the inner focus ring 21 and the inner peripheral portion 22a of the outer focus ring 22 overlap. The distance between the lower surface of the protrusion 43 and the inner peripheral portion 22a of the outer focus ring 22 is larger than the gap between the upper surface of the susceptor 6, that is, the upper surface of the electrostatic chuck 11 and the lower surface of the upper electrode 41. It is set short. The corners of the shield ring 42 are all formed in a shape curved outwardly convex, so that the gas is smoothly discharged without stagnant.

An exhaust pipe 52 is connected to the lower part of the processing vessel 3 and communicates with a vacuuming means 51 such as a vacuum pump. The exhaust pipe 52 is disposed around the susceptor 6.
, The inside of the processing chamber 2 is 10 mTorr to 100 mT
It is possible to evacuate to an arbitrary degree of reduced pressure in orr.

Next, a high-frequency power supply system of the etching apparatus 1 will be described.
Power from a high frequency power supply 53 that outputs high frequency power of 0 kHz is supplied via a matching unit 54. On the other hand, to the upper electrode 41, power is supplied from a high frequency power supply 56 that outputs a high frequency power of 1 MHz or higher, for example, 27.12 MHz, which is higher than the high frequency power supply 53, via a matching unit 55. It has a configuration.

A load lock chamber 62 is adjacent to the side of the processing container 3 via a gate valve 61. In the load lock chamber 62, a wafer W as a substrate to be processed is provided.
A transfer means 63 such as a transfer arm is provided for transferring the wafers to and from the processing chamber 2 in the processing container 3.

The main part of the etching apparatus 1 according to the present embodiment is configured as described above. For example, the operation and the like in the case of performing an etching process on an oxide film (SiO ₂ ) of a silicon wafer W will be described. First, after the gate valve 61 is opened, the transfer means 63 loads the wafer W into the processing chamber 2. At this time, the susceptor 6 is lowered by the operation of the drive motor 8, and is in a standby state for receiving the wafer W. After the wafer W is placed on the electrostatic chuck 11 by the transfer means 63, the transfer means 63
The gate valve 61 is closed, and the susceptor 6 is raised to a predetermined processing position by the operation of the drive motor 8.

Next, the inside of the processing chamber 2 is depressurized by the evacuation means 51, and after reaching a predetermined depressurization degree, a CF ₄ gas is supplied from the processing gas supply source 38, and the pressure of the processing chamber 2 becomes, for example, It is set and maintained at 10 mTorr.

The high frequency power supply 5 is connected to the upper electrode 41.
When a high frequency power having a frequency of 27.12 MHz is supplied from 6, plasma is generated between the upper electrode 21 and the susceptor 6. Also, with a slight delay (timing delay of one second or less), the high frequency power having a frequency of 800 kHz is supplied from the high frequency power supply 54 to the susceptor 6. By causing the susceptor 6 to supply high-frequency power at a delayed timing in this manner, it is possible to prevent the wafer W from being damaged by an excessive voltage.
Then, the CF ₄ gas in the processing chamber 2 is dissociated by the generated plasma, and the fluorine radicals generated at that time are converted into a silicon oxide film on the surface of the wafer W while the incident speed is controlled by the bias voltage applied to the susceptor 6 side. (SiO ₂ ) is etched.

In this case, the susceptor 6 is provided with an outer focus ring 22 on the outer periphery of an inner focus ring 21 arranged so as to surround the wafer W, and above the outer focus ring 22, around the upper electrode 41. Since the projection 43 of the shield ring 42 is located and the gap therebetween is shorter than the gap between the upper surface of the electrostatic chuck 11 and the lower surface of the upper electrode 41, the susceptor 6
The diffusion of the plasma generated between the electrode and the upper electrode 41 is suppressed, and the density of the plasma is increased. Of course, even if the pressure in the processing chamber 2 is as high as 10 mTorr, the diffusion of plasma can be effectively suppressed. Therefore, it is possible to cope with the etching process of a highly integrated semiconductor device of 64M DRAM, and the etching rate becomes high. Further, since the inner focus ring 21 is disposed around the wafer W, fluorine radicals as etchant ions can be efficiently removed from the wafer W.
And a silicon oxide film (SiO ₂ ) on the surface of the wafer W
Has an even higher etching rate.

By the way, there is a tendency that the plasma density tends to increase in the vicinity of the inner periphery of the protruding portion 43 in which the plasma is to be confined.
A position corresponding to a portion where the outer periphery of the inner focus ring 21 and the inner periphery of the outer focus ring 22 overlap, that is, a portion where the step portion 21b of the inner focus ring 21 and the inner peripheral portion 22a of the outer focus ring 22 overlap. It is located above. The overlapped portion has a configuration in which the outer focus ring 22 as an insulator is thinly overlapped on the inner focus ring 21 as a conductor, so that the bias is slightly released. The plasma is originally thinner than the center of the wafer W. Therefore, the plasma density in the vicinity of the inner periphery of the protruding portion 43 is maintained at a density that is not so different from that of the central portion. As a result, the plasma density of the peripheral portion of the wafer W is almost the same as that of the central portion. . Therefore, the uniformity of the etching on the wafer W is good.

The CF ₄ gas used for etching is discharged from the space between the shield ring 42 and the outer focus ring 22 to the outside of the processing chamber 2 from the exhaust pipe 52 through the baffle plate 25 as described above. In order to suppress plasma diffusion, a protrusion 43 is formed on the lower surface of the shield ring 42, whereby the flow path is also narrowed. Accordingly, the gas conductance is reduced accordingly, but in the present embodiment, the outer peripheral edge 43b of the projecting portion 43 is located significantly inside the outer peripheral edge of the outer focus ring 22, and The thickness is set extremely thin. Therefore, after all, the gas conductance between the shield ring 42 and the outer focus ring 22 does not decrease so much, and smooth gas exhaust is realized. Therefore, there is no need to particularly increase the flow rate of the etching gas as compared with a conventional etching apparatus of this type.

Next, the relationship between the length of the projecting portion 43 and the etch rate will be described based on data obtained when the inventors actually performed etching using the etching apparatus 1 according to the embodiment, as shown in FIG. Then, the gap G between the upper surface of the wafer W and the lower surface of the upper electrode 41 was set to 15 mm, and the minimum gap MG between the upper surface of the outer focus ring 22 and the lower surface of the protrusion 43 was changed to etch the 8-inch wafer W. The results were obtained as shown in FIG. The etching conditions at this time are as follows. The high frequency power supplied to the upper electrode 41 is 2k at a frequency of 27.12 MHz.
W, the high frequency power supplied to the susceptor 6 is 800 k
Vpp (plasma potential) at 1.5 Hz is 1.5 kV, and the etching gas is C ₄ F ₈ / CO / Ar / O ₂ = 15.
The mixed gas was supplied at a flow rate of / 15/255/6 (SCCM).

According to the results shown in the table of FIG. 4, the smaller the minimum gap MG, the higher the etch rate. However, it was also confirmed that if the minimum gap MG was made smaller than 6 mm, the uniformity would be greatly reduced. Therefore, in consideration of uniformity, the preferable range of the minimum gap MG is 6 to 10 mm,
In particular, about 8 mm is practically preferable.

Next, the relationship between the protrusion 43 and the gas conductance will be described. As shown in FIG. 3, the thickness of the protrusion 43 is D, and the distance from the inner periphery of the protrusion 43 to the outer periphery of the outer focus ring 22 is as shown in FIG. When the length is L, the wafer W
When the gap G between the upper surface and the lower surface of the upper electrode 41 is set to 25 mm, the minimum gap MG = 8 mm, L = 25 mm, and the internal pressure of the processing chamber 2 is set to 45 mTorr, the gas conductance becomes 468 (l / l) when D = 10 mm. s) and D =
When it was 3 mm, it was 625 (l / s). The conventional type, that is, the protrusion 43 was not formed as in the present embodiment, but a narrow space for confining the plasma was formed by an insulator having a flat lower surface as disclosed in Japanese Patent Application Laid-Open No. 62-69620. In this case, if the length in the radial direction (corresponding to D) was 25 mm, the gas conductance at that time was 312. Therefore, when suppressing the plasma diffusion, the gas conductance may be better if the protrusion 43 having a short D is formed on the shield ring 42 and the plasma is confined by the protrusion 43 as in the present embodiment. It could be confirmed.

In the above-described embodiment, the projecting portion 43 of the shield ring 42 has a shape in which the inside and outside are formed vertically, but instead the projecting portion 43 has a shape as shown in FIG. Shield ring 45 having portion 44
May be attached. The protruding portion 44 is vertically formed on the inner peripheral side, but is tapered on the outer peripheral side. According to the shield ring 45, the gas does not stagnate outside the protruding portion 44 as compared with the case of the shield ring 42, and a deposit or the like is less likely to adhere.

Further, as for the outer shield ring, a tapered outer shield ring 46 may be used as shown in FIG. In this case, the angle formed between the baffle plate 25 and the baffle plate 25 is an obtuse angle as compared with the case of the above-described embodiment, so that the gas hardly stagnates and deposits and the like hardly adhere. Therefore, the use of the shield ring 45 and the outer shield ring 46 shown in FIG.

Although the above-described embodiment is configured as an apparatus for performing a process of etching a silicon oxide film (SiO ₂ ) on the surface of a silicon semiconductor wafer,
The present invention is not limited to this, and the present invention can of course be configured as an apparatus for performing an etching process of various insulating films, for example, a silicon nitride film (SiN), a TEOS oxide film, and a BPSG film.

[0039]

According to the etching apparatus of the first to fourth aspects, it is possible to prevent the diffusion of plasma without unduly increasing the plasma density in the peripheral portion of the substrate to be processed than in the central portion. Therefore, fine, uniform, and high-speed etching can be performed on a substrate to be processed under a high plasma density. Further, in the etching apparatus of the present invention, the gas conductance is good while preventing the diffusion of the plasma as described above, and the plasma can be efficiently confined without suppressing the flow rate of the processing gas such as the etching gas. . In the etching apparatus according to the second aspect , plasma diffusion can be prevented at a place closer to the substrate to be processed than in the case of the first aspect. Can be etched.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view of an etching apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged explanatory view of a main part of FIG. 1 showing a positional relationship between a shield ring and an outer focus ring in the etching apparatus of FIG. 1;

FIG. 3 is an explanatory diagram showing a distance relationship between a shield ring and an outer focus ring in the etching apparatus of FIG. 1;

FIG. 4 is a table showing a relationship between a gap between a projection of a shield ring and an outer focus ring and an etching rate when etching is performed using the etching apparatus of FIG. 1;

FIG. 5 is an explanatory view showing another example of a shape of a shield ring and an outer focus ring that can be used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Etching apparatus 2 Processing chamber 3 Processing container 6 Susceptor 21 Inner focus ring 22 Outer focus ring 41 Upper electrode 42 Shield ring 43 Projection 52 Exhaust pipe 53, 55 High frequency power supply W Wafer

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-114584 (JP, A) JP-A-3-291928 (JP, A) JP-A-62-269620 (JP, A) JP-A-60-1985 126832 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 21/3065 C23F 4/00

Claims (4)

(57) [Claims] An upper electrode and a lower electrode are opposed to each other in a processing chamber which can be freely depressurized, and plasma is generated between the upper electrode and the lower electrode by supplying high-frequency power, so that a processing target on the lower electrode is generated. In an etching apparatus configured to etch a substrate, an upper insulator is provided around an upper electrode, and a conductive first annular body and an outer periphery of the first annular body are provided around a lower electrode. And a second annular body made of an insulator located at an inner peripheral edge of an annular protrusion formed on a lower surface of the upper insulator.
The outer peripheral edge is set so as to be located above the second annular body.
An etching apparatus, wherein a narrowest distance between the annular protrusion and the second annular body is set smaller than a distance between the upper electrode and the lower electrode. 2. An outer peripheral portion of the first annular body and a second annular member.
The inner periphery of the annular body is superimposed, and the outer peripheral edge of the protrusion is located above the second annular body.
And, the inner periphery of the protrusion, the outer peripheral portion of said first annular member
The etching apparatus according to claim 1, wherein the etching apparatus is set at a position corresponding to the overlapping portion with the inner peripheral portion of the second annular body . 3. The high-frequency electric power is applied to both the upper electrode and the lower electrode.
3. The method according to claim 1, wherein power is supplied.
An etching apparatus according to any of the preceding claims. 4. The conductive first annular member is made of silicon.
A method according to any one of claims 1, 2, or 3, wherein
An etching apparatus as described in the above.