JP3210207B2 - Plasma processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus.
Is what you do.

[0002]

2. Description of the Related Art For example, in the case of a plasma processing apparatus, for example, in a semiconductor manufacturing process, it has been widely used for performing a surface treatment of a semiconductor wafer (hereinafter, referred to as a "wafer"). A so-called parallel plate type plasma processing apparatus has advantages such as excellent uniformity, being capable of processing a large-diameter wafer, and the apparatus configuration is relatively simple, so that it is widely used.

In the above-mentioned conventional general parallel plate type plasma processing apparatus, electrodes are provided vertically above and below in a processing chamber so as to face each other, and a wafer to be processed is mounted on, for example, a lower electrode. In the case of an etching process, for example, an etching gas is introduced into the processing chamber, and high-frequency power is applied to the electrodes to generate plasma between the electrodes, and the etchant ions generated by dissociation of the etching gas cause The wafer is configured to be etched. In such a case, the etching gas is directly discharged toward the wafer from a large number of holes of the gas diffusion plate constituting the discharge portion provided on the surface of the upper electrode facing the wafer.

[0004] By the way, the processing by plasma processing,
As semiconductor devices become more highly integrated, there is a demand for increasingly finer processing, higher processing speed, and uniform processing.
Therefore, it is necessary to further increase the density of the plasma generated between the electrodes. Further, for example, a silicon oxide film (S
When a contact hole is formed in iO ₂ ), extremely high selectivity is required.

Regarding the above points, for example, Japanese Patent Application Laid-Open No. 57-15 / 1982
Japanese Patent Publication No. 9026 “Dry etching method” discloses a magnetron type plasma processing apparatus using a magnetron as a new plasma generation method, and Japanese Patent Publication No. 58-12346 “Plasma etching apparatus” discloses a conventional plasma processing apparatus. In addition, a configuration in which a common anode electrode such as a grid is used between the upper and lower electrodes is disclosed. The electrodes of this type of conventional device generally have a lower electrode made of aluminum and an upper electrode made of carbon.

[0006]

However, in the above-described magnetron-type plasma processing apparatus, a high-density plasma can be obtained in a relatively high vacuum, but the change in the magnetic field is much slower than the frequency of the high-frequency electric field. Therefore, the state of the plasma changes with the change of the magnetic field, and this change changes the energy and directionality of the ions, which may cause element damage or deterioration of the processed shape.
The common anode configuration has the advantage that the ion energy and the current density can be controlled independently, but the plasma diffuses through the grid, the ion current density incident on the wafer decreases, and the processing rate decreases. There is a possibility that the treatment may not be uniform or the treatment may not be uniform. When the atmosphere becomes high frequency and high vacuum with high fine processing, the impedance between the electrode and the inner wall of the processing vessel is reduced, and an environment in which plasma is more easily diffused is created.

When the plasma is diffused in the processing chamber as described above, not only does the plasma density decrease, but metal contamination and the like also occur on the processing chamber walls, contaminating the wafer to be processed. I will. This tendency becomes even more remarkable in plasma processing at a high degree of reduced pressure necessary for high-fine processing, which is increasingly required in the future.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and a first object of the present invention is to provide a relatively simple parallel plate type in order to perform a finer and finer plasma processing. It is an object of the present invention to realize a high plasma density by confining the plasma in the space between the electrodes without diffusing the plasma into the processing chamber while adopting the apparatus configuration described above, and not to cause contamination on the inner wall of the processing chamber .

[0009]

According to the first aspect of the present invention, a plasma is generated by high frequency power between a first electrode and a second electrode provided to face each other in a processing chamber. In a plasma processing apparatus configured to perform a process on the object to be processed in the processing chamber under the plasma atmosphere, the plasma processing apparatus is disposed so as to surround a space region between the electrodes in the processing chamber from a side. , shapes have a cylindrical ground electrode, the inner periphery of the ground electrode, which protrudes inwardly
A plasma processing apparatus is provided.

[0010] The cylindrical ground electrode has a substantially annular shape surrounding the interelectrode space, and the inner periphery thereof may be convexly curved toward the interelectrode space. May be done.

According to the second aspect, the plasma is generated between the first electrode and the second electrode provided in the processing chamber so as to face each other by the high frequency power, and In the plasma processing apparatus configured to perform the processing under the plasma atmosphere, a substantially annular third electrode is provided near the outer periphery of the first electrode, and the third electrode is provided near the outer periphery of the second electrode. Provides a substantially annular fourth electrode,
The third electrode and the fourth electrode are respectively grounded,
Further, the third electrode and the fourth electrode are arranged to face each other over the entire circumference, and the third electrode and the fourth electrode are
The cross section is almost triangular so that its inner surface forms a slope
A plasma processing apparatus having a shape is provided. Further, the third electrode and the fourth electrode may be arranged so that the outer peripheral portions of the third electrode and the fourth electrode overlap.

In this case, the third electrode arranged near the first electrode and the fourth electrode arranged near the second electrode are opposed to each other, and their outer peripheral edges overlap. (So that the outer peripheral edges of the two opposing electrodes coincide with each other when viewed from a plane).

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

In yet above each plasma processing apparatus,
The processing chamber in which the processing chamber is formed is grounded, and the first and second electrodes are insulated from the processing chamber.
High-frequency power from the two high-frequency power sources is configured to be selectively applied to either the first electrode or the second electrode,
Further, the first and second electrodes may be configured so as to be freely grounded. In this case, one of the first and second electrodes is changed to the high-frequency power application electrode by the switching. At this time, the other electrodes may be configured to be grounded at the same time.

In each of the above plasma processing apparatuses,
The output of the high-frequency power may be periodically modulated, and the output modulation width in such a case is such that the output at the minimum is in the range of 1/2 to 1/5 of the output at the maximum. A more preferable result is obtained by setting.

[0021]

In the above-described plasma processing apparatus , the first electrode constitutes an upper electrode, the second electrode constitutes a lower electrode, a relative high-frequency power is applied to the upper electrode, and the lower electrode is applied to the lower electrode. A relative low-frequency power may be applied, and a gap (gap) length between the upper electrode and the lower electrode may be set to 10 to 40 mm.

The relative high frequency power is a frequency of 10 to 4
The power of 0 MHz is referred to, and the relative low-frequency power is power having a frequency of 300 kHz to 3 MHz.

When the voltage is applied to both upper and lower sides,
A more preferable result is obtained by configuring the upper electrode to be applied earlier than the lower electrode, or for stopping the power application, by configuring the lower electrode to be stopped earlier than the upper electrode. can get.

In this type of plasma processing apparatus, a matching device such as a matching device or a matching device usually called a matching device is provided. In such a matching device, the impedance and the phase are controlled independently. Then, favorable results can be obtained.

In each of the plasma processing apparatuses described above, the pressure in the processing chamber may be set to 5 mTorr to 100 mTorr.

(Function) A space area between the electrodes in the processing chamber as in claim 1.
Having a ground electrode arranged so as to surround the area from the side.
Then, the plasma stays in the space between the electrodes and does not diffuse to the surroundings. Therefore, the plasma density in the processing region increases, and no contamination occurs on the inner wall of the processing chamber. That is, ions to be diffused is actively moved to the third electrode side, the diffusion of the results to the plasma is prevented.

In view of only the purpose of preventing such plasma diffusion , the ground electrode serving as the plasma confining means is preferably, for example , a cylindrical one, but the exhaust of the etching gas introduced into the space between the electrodes is taken into consideration. Then, by providing a plurality of through-holes as described above, it is possible to prevent plasma diffusion without impairing the exhaust and at the same time.

When the grounded electrode is provided as described above, ions are positively attracted, so to speak, so that the electrode has a substantially annular shape surrounding the space between the electrodes, and the inner periphery thereof is formed. When curved convexly toward the inter-electrode space, the surface area exposed to the plasma side increases, and the intended purpose can be achieved even for plasma generated by high power.

As described in the second aspect, when the ground electrodes having a substantially annular shape are arranged near the first electrode and near the second electrode, respectively, the first electrodes on the opposite sides are respectively disposed. And each of the ions from each of the second electrodes can be attracted, thereby preventing plasma diffusion. That is, the third electrode can call in corresponding ions from the second electrode and the fourth electrode can call in corresponding ions from the first electrode, thereby preventing the diffusion of plasma. In this case, if the two grounded electrodes, that is, the third electrode and the fourth electrode are arranged so as to overlap with each other, the diffusion of plasma can be further prevented.

[0031]

[0032]

[0033]

In each of the plasma processing apparatuses configured as described above, if the high frequency power is applied to each of the first electrode and the second electrode, the voltage of each high frequency power can be independently varied. It is easy to do.

[0035]

[0036]

As described above, the processing chamber in which the processing chamber is formed is grounded, the first and second electrodes are insulated from the processing chamber, and high-frequency power from one high-frequency power supply is supplied. The first electrode or the second electrode is configured so as to be selectively applied to the first electrode or the second electrode.
If the first electrode is configured to be freely grounded, a mode in which the second electrode is grounded while the voltage is applied to the first electrode, and conversely, the high frequency is applied to the second electrode by grounding the first electrode. Two plasma processing modes, a mode for applying power and a mode for applying power, are obtained. Therefore, two different plasma processing modes are obtained in one processing chamber. For example, when an object to be processed is placed on the first electrode and an etching process is performed on the object, the former mode is used. In this mode, an etching process with a large DC bias can be performed, and in the latter mode, an etching process with a small DC bias can be performed. Therefore, different processes can be continuously performed in the same processing chamber, and application of the process can be expanded.

In this case, when the high-frequency power application side electrode is switched, the other electrodes are switched and grounded at the same time, so that the two modes can be switched by switching one relay system, for example.

If the output of the high frequency power is periodically modulated in each of the above plasma processing apparatuses,
It is possible to repeat the rise and fall of the plasma density, and it is possible to control the dissociation of gas components in the plasma.For example, in the etching of a contact hole, the etching proceeds at a high output, and the inside of the hole at a low output. It is possible to adopt a process of discharging the etching reaction product of the above. Accordingly, it is possible to perform etching with excellent vertical anisotropy that can increase the etching rate and reduce the difference in size between the hole bottom and the hole entrance. In such output modulation, if the output at the minimum is set so as to fall within a range of 1/2 to 1/5 of the output at the maximum, it is possible to maintain the plasma state and to discharge the etching reaction products. It can be in a favorable state.

If the gap length between the upper electrode and the lower electrode is set to 10 to 40 mm and the relative high frequency power and the relative low frequency power are applied to the upper and lower opposed electrodes respectively to generate plasma , or falling edge of Chin Great, uniformity, and it is possible to perform a consistent treatment of the balance relates the stability of the plasma. The gap length is 15 to 30 mm,
In particular, if the distance is set to about 25 mm, still more preferable results can be obtained.

When the voltage is applied to both the upper electrode and the lower electrode, the upper electrode is applied first, and the lower electrode is applied later to generate the plasma. An excessive voltage is not applied to the object placed on the electrode, plasma is easily generated, and there is little risk of damaging the object. Also, when the plasma is extinguished, if the applied power on the lower electrode side is stopped first and then the applied power on the upper electrode side is stopped later, the deposit does not progress and damage to the workpiece is prevented. It becomes possible to do. In short, if such an application and stop sequence are adopted, a state in which a voltage is applied only to the lower electrode on which the object to be processed is placed is avoided,
The object to be processed is protected from excessive voltage. Note that the desired effect can be obtained by setting the delay timing to, for example, 1 second or less.

As described above, if the matching means is configured to control the impedance and the phase independently,
This makes it less likely to be affected by disturbances, and makes it easier to match with load fluctuations.

[0043] and the processing chamber internal pressure 5mTorr~100
By configuring so as to be freely set to mTorr, high fine processing under a high degree of vacuum becomes possible.

[0044]

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 a first embodiment.
Are configured as a so-called parallel plate type etching apparatus in which electrode plates face each other in parallel.

[0045] The etching apparatus 1 includes, for example, the surface has a been processing container 2 formed into a cylindrical shape made of oxide anodized aluminum, the processing vessel 2 is grounded. At the bottom of the processing chamber formed in the processing chamber 2, a substantially columnar shape for mounting an object to be processed, for example, a semiconductor wafer (hereinafter, referred to as “wafer”) W via an insulating plate 3 such as ceramic. The susceptor support 4 is accommodated, and a susceptor 5 constituting a lower electrode is provided above the susceptor support 4.

A coolant chamber 6 is provided inside the susceptor support 4, and a coolant for temperature control such as perfluoropolyether can be introduced into the coolant chamber 6 through a coolant introduction pipe 7. The introduced refrigerant circulates through the refrigerant chamber 6, and the cold generated during the circulation is transmitted from the refrigerant chamber 6 to the wafer W via the susceptor 5, and the processing surface of the wafer W is desired. It is possible to cool to temperature.

The susceptor 5 is formed in the shape of a disk having a convex upper surface center, and an electrostatic chuck 11 having substantially the same shape as the wafer W is provided thereon. This electrostatic chuck 11
Has a configuration in which a conductive layer 12 is sandwiched between two polymer polyimide films, and a DC high-voltage power supply 13 installed outside the processing vessel 2 is connected to the conductive layer 12 by, for example, 1. By applying a DC high voltage of 0.5 kV, the wafer W mounted on the upper surface of the electrostatic chuck 11 is suction-held at that position by Coulomb force.

An annular focus ring 15 is arranged on the peripheral edge of the upper end of the susceptor 5 so as to surround the wafer W mounted on the electrostatic chuck 11. The focus ring 15 is made of an insulating material that does not attract the reactive ions, and is configured so that the reactive ions generated by the plasma are effectively incident only on the wafer W inside the focus ring 15.

[0049] above the susceptor 5, and faces parallel to the susceptor 5, this than about 15~20mm about spaced apart so position, the upper electrode 21 via an insulating member 22, the processing vessel 2 Supported on top. The upper electrode 21 has a large number of diffusion holes 2 on the surface facing the susceptor 5.
3, an electrode plate 24 made of, for example, SiC or amorphous carbon, and an electrode support 25 made of a conductive material supporting the electrode plate 24, for example, aluminum whose surface is treated with anodized aluminum.

A ground electrode 27 serving as a third electrode as shown in FIG. 2 is provided on the outer periphery of the electrode support 25 with an annular insulating material 26 interposed therebetween. As shown in FIG. 1, the ground electrode 27 is provided so that the lower end thereof holds a gap through which the wafer W can pass between the focus ring 15 and the upper end thereof. 1. As shown in FIG. 2, it has a form protruding inward.
The ground electrode 27 is connected to the susceptor 5 and the electrode plate 2.
4 is arranged so as to surround the space region from the side.

A gas inlet 28 is provided at the center of the support plate 25 in the upper electrode 21, and a gas inlet pipe 29 is connected to the gas inlet 28. A gas supply pipe 30 is connected to the gas introduction pipe 29,
Further, the gas supply pipe 30 is branched into three and communicates with the corresponding processing gas supply sources 37, 38 and 39 via valves 31, 32 and 33 and mass flow controllers 34, 35 and 36, respectively. . In this embodiment, the processing gas supply source 37 supplies CF ₄ gas, the processing gas supply source 38 supplies Cl gas, and the processing gas supply source 39 supplies N ₂ gas which is an inert purge gas. Have been.

An exhaust pipe 41 is connected to the lower part of the processing vessel 2. The exhaust pipe 44 of the load lock chamber 43 adjacent to the processing vessel 2 via a gate valve 42 is connected to the exhaust pipe 41. It is connected to the evacuation means 45 and is configured so that evacuation can be performed to a predetermined reduced-pressure atmosphere. The wafer W, which is the object to be processed, is transferred between the processing container 2 and the load lock chamber 43 by a transfer means 46 such as a transfer arm provided in the load lock chamber 43. ing.

[0053] The high-frequency power for generating plasma in the etching apparatus 1 of the processing container 2, for example, supplied by two high frequency power supply 51, 52 to oscillate the 13.56MHz high frequency. That is, the high frequency power supply 5
1 is configured to apply high-frequency power to the upper electrode 21 via the matching unit 53, and the high-frequency power supply 52 is configured to apply high-frequency power to the susceptor 5 via the matching unit 54. I have. In addition, the upper electrode 21,
Since high-frequency power is applied to the susceptor 5 by independent high-frequency power sources, the voltage applied to the upper electrode 21 and the susceptor 5 is independently variable.

Further , between the matching unit 53 and the upper electrode 21, and between the matching unit 54 and the susceptor 5, phase detecting means 55 and 56 for detecting the phase signals of the current of the high-frequency power applied respectively. Are provided respectively. The phase signals detected by the phase detection means 55 and 56 are input to a phase controller 57, and the phase controller 57 sends the signals to the high-frequency power sources 51 and 52 based on the detected phase signals. On the other hand, they are controlled so as to oscillate high frequencies having phases different from each other by 180 °.

[0055] etching apparatus 1 according to a first embodiment
Is configured as described above. For example, the wafer W having a silicon substrate is
The case where the upper silicon oxide film (SiO ₂ ) is etched will be described. First, the wafer W to be processed is transferred to the transfer unit 46 after the gate valve 42 is opened.
Is loaded from the load lock chamber 43 into the processing container 2 and is placed on the electrostatic chuck 11. The wafer W is suction-held on the electrostatic chuck 11 by application of a high-voltage DC power supply 13. Thereafter, after the transfer means 46 is retracted into the load lock chamber 43, the inside of the processing container 2 is evacuated by the exhaust means 45.

[0056] On the other hand the valve 31 is opened, while the flow rate thereof is adjusted by the mass flow controller 34, CF ₄ gas from the processing gas supply source 37, a gas supply pipe 30,
The upper electrode 21 through the gas inlet pipe 29 and the gas inlet 28
Then, the liquid is uniformly discharged to the wafer W through the diffusion holes 23 of the electrode plate 24 as shown by arrows in FIG.

[0057] The pressure in the processing container 2, for example 1Pa
After being set and maintained, the high-frequency power supplies 51 and 52 are operated, and high-frequency powers whose current phases are different from each other by 180 ° are applied to the upper electrode 21 and the susceptor 5, respectively. Plasma is generated between
The wafer W is subjected to predetermined etching by radical components generated by dissociating the CF ₄ gas introduced into the processing container 2.

[0058] Such a plasma in the etching process is generated between the upper electrode 21 and the susceptor 5 as described above, as described above, the ground electrode 27, the space region between said upper electrode 21 and the susceptor 5 Is arranged so as to surround from the side part, ions to be diffused from the space region are attracted by the ground electrode and do not diffuse to the outside of the space region, for example, to the inner wall of the processing vessel 2. Therefore, the plasma density in the space region, that is, the plasma density in the processing region for the wafer W can be maintained high, and thereby, the wafer W can be processed with high precision.

Further , since the diffusion of ions to the inner wall of the processing vessel 2 is suppressed, the processing vessel 2
No contamination occurs on the inner wall due to etching of the inner wall or adhesion of a reaction product, and the inside of the processing container 2 is not contaminated. Therefore, the yield does not decrease from this point.

The high-frequency power applied to the upper electrode 21 and the susceptor 5 to generate plasma is:
Since the current phases are different by 180 °, high-frequency power can be applied to the plasma regardless of the type of the processing gas and the degree of pressure reduction, and the ion current density incident on the wafer W can be increased.

[0061] That is, when changing the phase difference between the frequency of the high frequency applied between the opposing electrodes power, plasma state changes (e.g., JP-A-2-224239). For example, when the voltage phases of the two high-frequency powers are substantially the same, the plasma spreads, the density decreases, and the processing speed decreases. On the other hand, when the voltage phase difference is shifted by 180 °, the plasma density increases. However, for example, when the frequencies are 380 kHz and 13.56 MHz, the voltage phase difference at which the plasma density becomes highest is different. This is considered to be because the impedance of the plasma changes. Similarly, when the composition of the processing gas is changed, the impedance of the plasma changes due to the difference in the ionization cross-sectional area or the difference in the dissociation characteristics of the gas, and the optimum voltage phase difference changes. Therefore, in the conventional method of applying high-frequency power by controlling the voltage phase, the current flowing from one electrode flows into the counter electrode due to the phase difference due to the change in plasma impedance. Otherwise, it would diffuse to other than the counter electrode, for example, to the inner wall of the processing vessel, and it was difficult to realize the state with the highest plasma density.

In this regard, as described above, by controlling the current phase to be 180 ° different from each other, regardless of the change in the plasma impedance, one electrode, for example, from the upper electrode 21 to the susceptor 5 as the other counter electrode. When trying to flow, the phase of the susceptor 5 is such that the current can flow, so that the current flows efficiently, and as a result, the plasma is confined between the upper electrode 21 and the susceptor 5 and the density thereof becomes high. It becomes.

Further, in this embodiment, as described above, since the plasma is confined also by the ground electrode 27, an extremely high plasma density can be realized by the combination of the two, and high fine processing can be performed. And

The ground electrode 27 used in the above embodiment was used.
Has a form in which it is formed to be convex inward. Instead, for example, as shown in FIG. 3, a simple cylindrical ground electrode 61 may be used as an electrode support through an insulating material 62. A configuration may be adopted in which the processing vessel 2 and the ground electrode 61 are arranged on the outer periphery of the body 25 and are grounded.

Further , in order to make the space between the opposing electrodes more closed, a cylindrical form in which the height of the ground electrode is further increased may be adopted. In such a case, a plurality of through holes 64 are formed around the ground electrode 63 as shown in FIG. 4 in order to sufficiently exhaust the processing gas introduced into the space between the opposed electrodes. It is preferable to keep it.

[0066] As yet another example of the ground electrode does not diffuse around the plasma confined between opposed electrode may be a ground electrode 65 and 66 as shown in FIG. 5, for example.
As can be seen from the figure, the ground electrodes 65 and 66 each have a substantially ring shape. The ground electrode 65 is disposed on the outer periphery of the upper electrode 21, and the ground electrode 66 is disposed on the outer periphery near the upper end of the susceptor 5. (In this case, a configuration may be provided above the so-called exhaust ring). As a result, charged particles that are to be diffused from the upper electrode 21 are attracted to the ground electrode 66, and charged particles that are to be diffused from the susceptor 5 are attracted to the ground electrode 65. As a result, the upper electrode 21 and the susceptor 5 The plasma generated in between does not diffuse to the inner wall of the processing container 2.

The ground electrodes 67 and 68 shown in FIG.
The shape of the electrode is changed to a ring shape and the cross section is made substantially triangular so that the inner surface forms a slope. According to the ground electrodes 67 and 68 having such a configuration, for example, the upper ground electrode 67 has a slope portion on the inner side directed toward the susceptor 5, and thus is more than the ground electrode 65 shown in FIG. It can attract charged particles efficiently,
Further, the effect of preventing plasma diffusion is improved.

The ground electrode shown in FIG. 5 and FIG.
Although all of them have a vertically opposed structure, the plasma diffusion preventing effect can be obtained without necessarily having such a structure.

In the above-described example, as a means for preventing the plasma diffusion, the configuration in which the third electrode other than the upper electrode 21 and the susceptor 5 is provided is adopted.
As shown in (1), a magnet may be arranged facing the vicinity of the upper electrode 21 and the susceptor 5. That is, the upper electrode 21 is provided with an annular insulating member 7 around the lower end of the electrode support 25.
1 are provided, and substantially columnar permanent magnets 72 shown in FIG. In the present embodiment, as shown in FIG.
The N-poles of all the permanent magnets 72 are located on the side and are arranged in an annular manner, as shown in FIG. 9, as shown in FIG.
It is set so that it becomes ゜.

[0070] As shown in the other 7, also the upper end outer periphery of the susceptor 5, an annular insulating member 73 is provided, inside the insulating member 73, the permanent magnet 72 having the same shape, and size, the same magnetic force The same number of permanent magnets 74 are arranged at the same intervals so as to face the respective permanent magnets 72. The magnetic poles of the permanent magnets 74 disposed on the susceptor 5 side are different from the magnetic poles of the opposing portions of the permanent magnets 72, that is, the S poles are located on the upper electrode 21 side. Therefore, the relationship between the magnetic poles of the permanent magnets 72 and 74 is as follows.
This is as shown in FIG.

[0071] By arranging the magnets in such a manner, the upper electrode 21 periphery, local magnetic field is generated between the susceptor 5 the periphery, charging the upper electrode 5 and the susceptor 5 between the space by the magnetic field Particles can be trapped from jumping out, and plasma can be confined in the interelectrode space. If the strength of the magnetic field is excessively large, the plasma itself may be biased to affect the plasma processing itself. Therefore, the strength of the magnetic field around the wafer W, which is the object to be processed, should be 10 Gauss or less. It is desirable to set.

In order to make the form of the local magnetic field more preferable, as shown in FIG.
For example, a magnetic body 75 may be provided at the upper end of the permanent magnet 72 and used together with the permanent magnet 72.

[0073] Further examples shown in FIG. 7 and 10, a permanent magnet 72 which is disposed on the upper electrode 21 side, the permanent magnet 74 disposed in the susceptor 5 side, between the upper and lower, mutually different Although the magnetic pole configuration was adopted, the same magnetic pole configuration was used between adjacent magnets. Instead, as shown in FIG. 12, the adjacent magnetic poles were arranged with different magnetic poles between adjacent magnets. If it does so, still more preferable effects can be obtained. That is, by arranging as shown in FIG. 12, a magnetic flux is generated not only in the upper and lower opposing portions but also in the adjacent opposing portions,
This results in a tighter trapping regime for charged particles.
Therefore, the plasma confinement effect is further improved as compared with the case of FIG.

[0074] Incidentally, with the high integration of semiconductor devices today as already described, even in the manufacturing process, it is required more fine processing. For example, even when a contact hole is formed by an etching process, fine processing is required so that the hole diameter is 0.3 μm and the hole depth is 1 to 2 μm. However, in the conventional parallel plate type plasma apparatus, since a high frequency power of a constant output is always applied, as shown in FIG.
The etching reaction product Z becomes difficult to be discharged, deposits on the bottom of the hole 81 or near the bottom, and the replacement with the etching gas is not performed smoothly. As a result, as shown in FIG. There has been a problem in that a truncated cone is formed or an etching rate is reduced, so that fine processing corresponding to high integration cannot be performed.

In order to cope with such a problem, for example, the outputs of the high-frequency power supplies 51 and 52 in the plasma processing apparatus 1 are controlled so that, for example, as shown in the graph of FIG.
The magnitude of the output may be repeatedly applied to the upper electrode 21 and the susceptor 5 every 10 ms. In FIG. 14, control is performed so that the output at the maximum is 1000 w and the output at the minimum is 200 w, which is 1/5 of that. By performing such control, the plasma density is increased when the power is large, and the etching is advanced, and when the power is small, the plasma density is reduced, so that the etching reaction products generated in the holes 82 shown in FIG. By facilitating the exchange with the etching gas, a hole having the same diameter at the entrance and the bottom of the hole 82 can be formed as shown in FIG. Note that the maximum and minimum powers and the cycle thereof may be appropriately selected according to the size of the target hole, the material, the type of the processing gas, and the like.

The above etching apparatus 1 uses two high-frequency power sources for generating plasma and
And the susceptor 5 is configured to apply a high frequency. However, if one of the electrodes is always grounded by switching and can be applied only to the other electrode, one device can be used. The configuration allows two different modes of etching to be performed.

[0077] In addition to performing the switching of Kakaru using one high frequency power source are also possible. The example shown in FIG. 16 is an etching processing apparatus 9 capable of performing such two different modes of etching using one high-frequency power supply 91.
2, an upper electrode 94 and a lower electrode 95 are provided in a grounded processing container 93 which can be freely depressurized, facing vertically. And, in the upper part of the processing container 93,
A first vacuum relay 96 is housed in the shield box 97 and switches connection of the upper electrode 94 to the high-frequency power supply 91 or the processing container 93. The matching box 98 houses a second vacuum relay 99 for switching the lower electrode 95 to the high-frequency power supply 91 or the ground side, and turning ON / OFF the path of the high-frequency power supply 91 leading to the first vacuum relay 96. It is responsible for switching OFF.

The etching apparatus 9 having such a configuration
According to FIG. 2, in the state of FIG.
In the IE (reactive ion etching) mode, the upper electrode 94 is grounded, and the lower electrode 95 is supplied with high-frequency power from the high-frequency power supply 91 to apply to a workpiece such as a wafer existing between the electrodes. In addition, it is possible to perform fine processing in a high vacuum region and etching processing with high controllability in a vertical shape.

If the first vacuum relay 96 and the second vacuum relay 99 are respectively switched to the PE (plasma etching) mode in which the DC bias is small as shown in FIG. 17, the lower electrode 95 is grounded, and the upper electrode 94 is connected to the high frequency power supply. The high-frequency power from the electrode 91 is applied, and an object to be processed such as a wafer existing between the electrodes is less damaged, and an etching process with high dimensional control can be performed. Therefore, the first
By simply switching between the vacuum relay 96 and the second vacuum relay 99, two different etching processes can be continuously performed on the same object in the same processing chamber, thereby expanding the application of the process. Can be achieved.

[0080] Still another embodiment will be described, FIG. 18 is a cross-section of the etching apparatus 101 of the second embodiment has a configuration for applying a high frequency power different frequencies vertically opposed electrode shown schematically A processing chamber 102 of the etching processing apparatus 101 is formed in a processing vessel 103 formed of a cylindrical shape made of aluminum or the like which is airtightly closable and anodized, and the processing vessel 103 itself is grounded. . A processing object, for example, a semiconductor wafer (hereinafter, referred to as a “wafer”) W is placed on the bottom of the processing chamber 102 formed in the processing container 103 via an insulating plate 104 made of ceramic or the like. A susceptor support 105 having a columnar shape is accommodated therein, and a susceptor 106 constituting a lower electrode is provided above the susceptor support 105.

A refrigerant chamber 107 is provided inside the susceptor support base 105.
As in the etching apparatus 1 described above, a refrigerant for temperature adjustment can be introduced through a refrigerant introduction pipe, and the introduced refrigerant circulates through the refrigerant chamber 107. Heat is transferred to the wafer W via the susceptor 106, and the processing surface of the wafer W can be cooled to a desired temperature. Further, a heating means 108 such as a ceramic heater is provided between the susceptor 106 and the refrigerant chamber 107, and the cooling means of the refrigerant chamber 107 and the heating means 108
The wafer W can be set and maintained at a predetermined temperature.

The susceptor 106 is provided with an electrostatic chuck 111, and the wafer W is placed on the upper surface of the electrostatic chuck 111 by applying a high DC voltage from a DC high voltage power supply 112 installed outside the processing chamber 103. Adsorbed and held. In addition, an annular focus ring 113 is disposed at an upper peripheral portion of the susceptor 106 with an insulating material 113 interposed therebetween.
Further, an annular ground electrode 115 is provided.

[0083] above the susceptor 106, in parallel to face the susceptor 106, with a gap length of about 25 mm, the upper electrode 121, through the insulating support 122, the process chamber 1
03 is supported on the top. This upper electrode 121
Similarly to the upper electrode 21 in the etching apparatus 1 described above, a large number of diffusion holes 123 are formed on the surface facing the susceptor 106.
have. On the outer periphery of the insulating support member 122, an annular ground electrode 124 is provided so as to further surround the upper electrode 121. The outer peripheral edges of the ground electrode 124 and the ground electrode 115 are as shown in FIG.
As shown in FIG.

A gas inlet 125 is provided at the center of the upper electrode 121, and an etching gas, for example, CF ₄ gas from a processing gas supply source 127 is supplied to the processing chamber 1 through the diffusion hole 123 via a mass flow controller 126.
02 can be freely supplied. On the other hand, an exhaust pipe 128 communicating with vacuum evacuation means (not shown) such as a vacuum pump is connected to a lower portion of the processing chamber 103.
The inside can be evacuated to an arbitrary degree of reduced pressure within a range of 5 mTorr to 100 mTorr.

[0085] Next, application configuration of a radio-frequency power to the susceptor 106 and the upper electrode 121 to be the lower electrode of the etching apparatus 101 will be described. First, to the susceptor 106, the power of a relative low-frequency power supply 131 that outputs a relatively low frequency of, for example, 800 kHz is applied via a matching unit 132. This matching device 132
As shown in FIG. 18, the induction coil 133 and the variable capacitance 133 are connected in series, and the other end of the variable capacitance 134 whose one end is grounded is connected in parallel. With such a configuration, it is possible to individually control the impedance of the power from the relative low-frequency power supply 131 with the induction coil 133 and the variable capacitor 133, and control the phase thereof with the variable capacitor 134 to achieve matching. It is possible. On the other hand, the upper electrode 121 is configured to receive a high frequency from a relative high frequency power supply 142 that outputs a relative high frequency power having a frequency of, for example, 27 MHz via a matching unit 141.

The etching apparatus 1 according to the second embodiment
01 is configured as described above. For example, an operation in the case of performing an etching process on an oxide film of a silicon wafer W will be described. CF ₄ from the processing gas supply source 127 in the processing chamber 102 will be described. After the gas is supplied and the pressure in the processing chamber 102 is set and maintained at, for example, 10 mTorr, a relative high frequency power having a frequency of 27 MHz is first applied to the upper electrode 121 from the relative high frequency power supply 142. Then, at a timing of 1 second or less, a relative low frequency of 800 kHz is applied to the susceptor 106 from the relative low frequency power supply 131, and plasma is generated between the upper electrode 121 and the susceptor 106. By delaying the application of the susceptor 106, the wafer W is not likely to be damaged by an excessive voltage.

[0087] Then by radical component of CF ₄ gas dissociated by the generated plasma silicon oxide film on the surface of the wafer W (SiO ₂₎ is gradually etched. In this case, first, the ground electrode 1 located around the upper electrode 121
24 and the ground electrode 11 located around the susceptor 106
By 5 the generated plasma is confined, its diffusion is prevented and a high density is maintained.

In the case of the second embodiment, as shown in FIG. 19, since the outer peripheral edges of the ground electrode 124 and the ground electrode 115 are disposed so as to overlap in the vertical direction, the effect of confining the plasma is obtained. Is extremely large.
That is, as shown in FIG. 20, for example, if the ground electrode 124 is located on the outer periphery and the outer peripheral edge does not overlap in the vertical direction, the plasma is diffused to some extent. When the outer peripheral edges overlap in the vertical direction, there is no room for plasma to diffuse outside, and an extremely high density can be secured. Therefore, from this point, a fine etching process can be performed first.

[0089] Incidentally, according to the inventors, the upper electrode 12
1, the gap length between the susceptor 106, the etching rate, the uniformity of the etching rate (distribution of the etching rate on the wafer W), and the stability of the plasma (stability from the viewpoint of plasma startup, maintenance, and diffusion). It has been confirmed that there is a relationship shown in FIG.

[0090] Namely as the gap length is long, the etching rate (E / R) and uniformity (U) is reduced, contrary plasma stability (S) is to improve. In order to realize a high yield and a fine etching process, these 3
The two elements need to be balanced,
According to the results obtained by the inventors, as shown in the graph of FIG. 21, it was found that these three elements can be obtained with the best balance when the gap length is around 25 mm.

In this respect, in the second embodiment, since the gap length between the upper electrode 121 and the susceptor 106 is set to 25 mm as described above, a fine etching process with a high yield on the wafer W is realized. It has become possible. Since the desired etching process is various, it is not always necessary to set this to 25 mm. As can be seen from the graph of FIG.
10 well-balanced etching treatments in the range of 35 mm
Even between mm and 40 mm, a relatively well-balanced etching process can be realized.

[0092] Incidentally in the plasma processing apparatus using such a high frequency conventionally, to take the high-frequency matching, the electrode applied with a high frequency power source, eg, between the lower electrode, as shown in FIG. 22 A matching unit 151 is provided. The conventional matching device 151 has a configuration in which variable coils 154 and 155 are arranged in series between a lower electrode 152 and a high-frequency power supply 153, and a grounded capacitor 156 is connected between the variable coils 154 and 155. Had. This allows a wide range of adjustment (matching). However, on the other hand, impedance and phase cannot be controlled independently, and there is also a problem that the frequency is easily affected by, for example, an upper electrode.

In this respect, in the etching apparatus 101 according to the second embodiment, as described above, the induction coil 133 and the variable capacitor 133 are connected in series, and the variable capacitor 134 whose one end is grounded. The other end is connected in parallel, so that the impedance and the phase of the power from the relative low-frequency power supply 131 can be controlled independently, so that the adjustment is easy and the relative high frequency from the upper electrode 121 is high. Less susceptible to the effects of Therefore, the generated plasma is extremely stable, and from this point, it is possible to realize a desired etching process.

In the etching apparatus 101 according to the second embodiment, both the upper electrode 121 and the susceptor 106 are fixed, and the gap between these electrodes is also fixed to 25 mm. In view of the characteristics of 21, the gap length may be made variable. For example, as shown in FIG. 23, if the susceptor 106 'is configured to be vertically movable by an appropriate adjusting mechanism 161, the gap length d between the upper electrode 121 and the susceptor 106' can be arbitrarily changed. Will be possible.

[0095] will be described other proposed example. FIG.
1 schematically shows a cross section of an etching apparatus 401 according to the proposed example.
The processing chamber 402 in FIG. 1 is formed in a processing container 403 formed in a cylindrical shape made of aluminum or the like, which is airtightly closable and anodized, and the processing container 403 itself is grounded. A substantially columnar susceptor 405 for mounting an object to be processed, for example, a semiconductor wafer (hereinafter, referred to as a “wafer”) W is accommodated at the bottom of the processing chamber 402 via an insulating support plate 404 made of ceramic or the like. The susceptor 405 forms a lower electrode.

An annular refrigerant chamber 406 is provided inside the susceptor 405.
A refrigerant for temperature adjustment is introduced via a refrigerant introduction pipe 407, circulates through the refrigerant chamber 406, and is discharged from a refrigerant discharge pipe 408. The cold generated during this time is transferred from the coolant chamber 406 to the wafer W via the susceptor 405, and the processing surface of the wafer W can be cooled to a desired temperature. Further, the susceptor 405 is provided with a heating means 409 such as a ceramic heater, for example, so as to heat the susceptor 405 to a desired temperature by power supply from a power supply 410 provided outside the processing container 403. Have been. Accordingly, the wafer W can be set and maintained at a predetermined temperature by the cold heat of the refrigerant chamber 406 and the heating means 409.

The susceptor 405 is provided with an electrostatic chuck 411, and the wafer W is placed on the upper surface of the electrostatic chuck 411 by applying a high DC voltage from a DC high voltage power supply 412 installed outside the processing container 403. Adsorbed and held. Further, a peripheral edge of an upper end of the susceptor 405 is arranged so as to surround the wafer W held on the electrostatic chuck 411.
An annular focus ring 413 made of an insulating material is provided.

[0098] Above the susceptor 405, in parallel to face the susceptor 405, with a gap length of about 25 mm,
An upper electrode 421 is supported above the processing container 403 via an insulating support member 422. This upper electrode 421
Has a portion in contact with the plasma made of SiO _{2 having} a thickness sufficient to transmit the applied RF power, and has a large number of diffusion holes 423 on the surface facing the susceptor 5.

A gas inlet 424 is provided at the center of the upper electrode 421, and an etching gas, for example, CF ₄ gas from a processing gas supply source 427 is supplied through the diffusion hole 423 via a valve 425 and a mass flow controller 426. It can be supplied into the processing chamber 402.

At the lower part of the processing chamber 403, an exhaust pipe 429 connected to vacuum means 428 such as a vacuum pump is connected, and the inside of the processing chamber 402 is set to 5 mTorr to 10 mTorr.
It is possible to evacuate to an arbitrary degree of reduced pressure within 0 mTorr.

[0102] Referring now to high-frequency power applying system of the etching apparatus 401, for the susceptor 405 is first a lower electrode, for example, the frequency is 800
Relative low frequency power supply 43 for outputting a relative low frequency of kHz
Power from 1 is applied via a matcher 432. On the other hand, with respect to the upper electrode 421,
A high frequency is applied from a relative high frequency power supply 433 that outputs a relative high frequency power having a frequency of, for example, 27.12 MHz.

[0102] Although is adapted to apply a high frequency of different frequencies to upper and lower electrodes in this manner, further in this example
Includes a high-pass filter 461, a low-pass filter 462
Is provided . That is, in the application path from the relative low frequency power supply 431 to the susceptor 405, one end of a high-pass filter 461 for blocking the intrusion of 800 kHz power and passing a high frequency of 27.12 MHz is connected in parallel, and the other end is connected. Ground. On the other hand, the application path applied from the relative high-frequency power supply 433 to the upper electrode 421 includes 2
A low-pass filter 46 that blocks the intrusion of 7.12 MHz power and passes the relatively low frequency power of 800 kHz.
2 are connected in parallel at one end and the other end is grounded.

With this configuration, the power of 800 kHz from the relative low-frequency power supply 431 is supplied to the susceptor 405 → the upper electrode 421 → the low-pass filter 462, while 27.1 from the relative high-frequency power supply 433.
The high frequency power of 2 MHz is applied to the upper electrode 421 → susceptor 4
05 → input to the high-pass filter 461. Therefore, mutual interference between the powers of these two different frequencies is prevented, the matching by the matching devices 432 and 434 is easy, the power loss is reduced, and the upper electrode 421 is reduced.
Efficient power supply can be realized between the power supply and the susceptor 405.

A load lock chamber 442 is adjacent to the side of the processing vessel 403 via a gate valve 441. In the load lock chamber 442, transfer means 443 such as a transfer arm for transferring a wafer W as a processing object to and from the processing chamber 402 in the processing container 403 is provided.

The etching apparatus 40 according to the above proposal
The main part of the semiconductor device 1 is configured as described above. For example, an operation when an oxide film of a silicon wafer W is etched will be described.
After the wafer 1 has been opened, the wafer W is carried into the processing chamber 402 by the transfer means 443 and is placed on the electrostatic chuck 411.
41 is closed. Next, the inside of the processing chamber 402 is evacuated
After the pressure is reduced by 28 and reaches a predetermined pressure reduction degree, CF ₄ gas is supplied from the processing gas supply source 427,
The pressure of the processing chamber 402 is set to, for example, 10 mTorr,
Will be maintained.

[0106] The frequency from the relative high-frequency power source 433 is relative high frequency of 27.12MHz is applied to the upper electrode 421, also have slightly delayed by this (1 second or less timing delay), to the susceptor 405 A relative low frequency of 800 kHz is applied from a relative low frequency power supply 431 to the upper electrode 421 and the susceptor 40.
5 is generated. Susceptor 4 like that
By delaying the application on the 05 side, it is possible to prevent the wafer W from being damaged by an excessive voltage.

[0107] and processed by the generated plasma chamber 4
CF ₄ gas is dissociated in 02, a silicon oxide film (SiO surface of the wafer W by fluorine radicals produced when the
₂ ) is being etched.

As described above, a power of, for example, 800 kHz is applied to the susceptor 405 while the upper electrode 42
1 is applied with a high frequency of 27.12 MHz,
Ions in the plasma generated at a high frequency of 2 MHz,
The incident speed is controlled at a relatively low frequency of 800 kHz. In this case, the frequency for controlling ions to be etched in such a manner, that is, the frequency of the relative low frequency applied to the susceptor 405 is determined. The following points must be kept in mind.

[0109] That is, when the relative frequency of the frequency and the closer the frequency to be applied to the upper electrode 421 side is applied to the susceptor 405, since both frequencies are close, it hardly exhibits the function of a high-pass filter 461 and low pass filter 462, as a result There is a possibility that matching cannot be properly performed or power loss occurs. On the other hand, the frequency is considerably lower than the frequency of the relative high frequency applied to the upper electrode 421 side,
When an extremely low relative low frequency of, for example, 10 kHz is applied to the susceptor 405, the energy width increases, and the number of ions having high energy increases. As a result, the wafer may be damaged, which is not preferable.

[0110] Therefore, in view of the above points, the susceptor 4
05 is applied to the upper electrode 42
It is necessary to select a frequency that is relatively far from the frequency on the one side and is not extremely low.

In this regard, the inventor has proposed that the susceptor 405
(The relationship between Vpp (plasma voltage and Vpp on the wafer W) in the application path to the wafer is determined for each frequency, and the relationship between Vpp on the wafer W and Vdc (self-bias voltage) on the wafer W is determined for each frequency. As a result of considering these characteristics and the energy width of ions at each frequency, the upper electrode 421 of the etching apparatus 401 has a 27.12 M
When applying the Hz of frequency, when considering the impedance of the apparatus, as shown in FIG. 25, the susceptor 405
Found that it is preferable to supply power at a frequency of 800 kHz. According to this, 800 kHz
Is a frequency that does not easily cause damage to the wafer and that can easily be matched.
Therefore, while using the high-pass filter 461 and the low-pass filter 462, the upper electrode
When a frequency power of 7.12 MHz and a frequency of 800 kHz is applied to the susceptor 405, it is possible to perform etching without power loss and without damage on the wafer W.

[0112] Then according to the etching apparatus to an embodiment of the present invention, it is possible to prevent deterioration of the etching chamber, a semiconductor wafer with a metal (hereinafter, referred to as "wafer") to reliably prevent contamination of such 26 and 27 show the technical idea of applying carbon so that
It will be described based on.

The cylindrical etching container 501 is made of a material, for example, aluminum whose surface is subjected to alumite treatment.
And an upper portion 501b of the etching container, which is disposed so as to hermetically close an upper opening of the lower portion of the etching container 501a and is formed in a disk shape from a similar material. O-rings 502 for keeping the inside airtight are appropriately disposed at these contact portions.

As shown in FIG. 27, openings 503 and 504 for loading and unloading wafers W are formed on both sides of the side wall of the lower portion 501a of the etching processing container so as to face each other. Outside each of the openings 503, 504, a corresponding gate valve 505, 506 is provided.
, Corresponding load lock chambers 507 and 508 are provided. These load lock chambers 507 and 508
A transfer mechanism 511 for loading and unloading the wafer W is provided therein (only one is shown). Usually, one of the load lock chambers, for example, the load lock chamber 50 is provided.
7 is dedicated to loading, and the other load lock chamber 508 is dedicated to unloading. In the drawing, 509 and 510 are gate valves for shutting off and opening the load lock chambers 507 and 508 and the outside.

In the etching processing container 501, an insulating support member 51 made of, for example, ceramics is used.
A susceptor made of, for example, aluminum whose surface is subjected to alumite treatment and formed in a disk shape, that is, a lower electrode 513 is provided so as to be supported by the second electrode 2. The lower electrode 513 is connected to a high-frequency power supply 515 via a matching circuit 514, and a refrigerant circulation path 516 for cooling is provided in the lower electrode 513. The upper surface of the lower electrode 513 is formed in a planar shape so that the wafer W can be suction-held by, for example, an electrostatic chuck (not shown) or the like.

[0116] On the other hand, portions facing the lower electrode 513 of the etching process container top 501b constitute the upper electrode 521. A gas supply pipe 522 led from a gas supply source (not shown) is connected to the upper electrode 521, and a predetermined etching gas supplied from the gas supply pipe 522 is a gas formed in the upper electrode 521. A wafer placed on the lower electrode 513 from the many holes 524 formed on the lower surface of the upper electrode 521 by being diffused in the diffusion space 523 by the gas diffusion plate having a large number of holes formed therein. It is configured to be uniformly supplied to W.

[0117] The lower portion of the etching chamber 501, and connected to an exhaust pipe 532 is connected to an exhaust pump 531, the periphery of the lower electrode 513, lower electrode 5
As shown in FIG. 27, a baffle plate 533 having a large number of through-holes is horizontally disposed so that uniform exhaust is performed from around the thirteen.

The baffle plate 533 is made of carbon, and the exhaust pipe 532 is provided at a predetermined distance from the etching processing container 501, for example, about several tens of centimeters to 1 meter.
a. The lower surface of the upper electrode 521 is covered with a carbon plate 525, and the inside of the through hole 524 of the upper electrode 521 is covered with a carbon coating 524a. Further, a carbon cylinder 534 is disposed in the etching processing container 501 so as to cover an inner wall surface thereof.

The carbon cylinder 534 has the above-mentioned 2
Openings 535 according to the three openings 503 and 504, respectively.
A shutter plate 536 made of carbon is provided so as to cover these openings 535 so as to be openable and closable. As shown in FIG. 27, these shutter plates 536 are formed of arc-shaped plates having substantially the same curvature as the inner wall surface of the etching container 501, and these shutter plates 536 are connected via a shaft 537 to the etching container. The air cylinder 538 is connected to an air cylinder 538 provided outside and is configured to move up and down by the expansion and contraction operation of the air cylinder 538. In addition, a mechanism for maintaining airtightness between these members, for example, a bellows mechanism (not shown) is provided in a portion where the shaft 537 penetrates in the etching processing container 501.

[0120] Each of carbon steel members, i.e., baffle plate 533, plate 525, cylinder 534, the shutter plate 536
Is set to a thickness of, for example, 1 to 20 mm.

In the etching apparatus configured as described above, the inside of the etching container 501 is set to a predetermined degree of vacuum by operating the exhaust pump 531 in advance. Then, the gate valve 509 of one of the load lock chambers, for example, the load lock chamber 507 is opened, and the transfer mechanism 51 is opened.
1, the wafer W to be processed is loaded into the load lock chamber 5.
07, the gate valve 509 is closed and the inside of the load lock chamber 507 is set to a predetermined degree of vacuum. Thereafter, the gate valve 505 is opened and the shutter plate 536 is moved from before the opening 503. , Transport mechanism 5
11, the wafer W is placed on the lower electrode 513.

[0122] Next, retracts the conveying mechanism 511 from the etching process vessel 501, the shutter plate 536 closes the gate valve 505 is positioned in front of the opening 535, in this state, predetermined etching gas from the gas supply pipe 522 For example, Cl ₂ + BCl ₃ is supplied, and at the same time, for example, 13.56 MHz high frequency power is supplied from the high frequency power supply 515 to turn the etching gas into plasma,
An etching process is performed on the wafer W by so-called reactive ion etching.

[0123] site is exposed to the plasma at this time etching chamber 501, except for the surface of the wafer W, are all a carbon. For this reason, for example, the opening 503
Of the through hole 524 of the upper electrode 521 can be prevented, so that the wafer W to be processed can be prevented from being contaminated by aluminum or the like. Also, a carbon plate 525 and a cylinder 53
4. The shutter plate 536 and the like are consumed by being etched, but can be dealt with by replacing these members which can be manufactured relatively inexpensively, and the deterioration of the etching processing container lower part 501a, the etching processing container upper part 501b, etc. Can be prevented.

In the case where aluminum is etched, the selectivity of the wafer W can be improved by the action of carbon etched from the plate 525, the cylinder 534, the shutter plate 536, and the like. That is, a sidewall protective film made of a carbon polymer is easily formed on the side wall of the non-etched portion where the photoresist as a mask is formed on the upper portion, so-called undercut of the side wall is suppressed, and the selectivity is improved. be able to.

Further, since the shutter plate 536 is formed of an arc-shaped plate having substantially the same curvature as the inner wall surface of the etching processing container 501, the etching processing container 5
01 generated in the etching processing vessel 5
01, the plasma density becomes uniform and uniform along the inner wall surface, the processing of the wafer W is made uniform, and the yield is improved.

In each of the above-described embodiments, the case where the object to be processed is a semiconductor wafer has been described. .

[0127]

According to the plasma processing apparatus of the present invention, it is possible to prevent the plasma from diffusing to the surroundings from the space between the electrodes in the processing chamber, to increase the plasma density in the processing region, No contamination occurs on the interior walls. In particular, the first as in claim 2
In case of installing the ground electrode around each of the electrode and the second electrode, the plasma confinement effect is large Monodea
You.

[0128]

[0129]

[Brief description of the drawings]

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

FIG. 2 is a partially cutaway perspective view of a ground electrode used in the etching apparatus of FIG.

FIG. 3 is an explanatory sectional view of a processing container using a ground electrode having another structure.

FIG. 4 is a perspective view of a ground electrode having a through hole.

FIG. 5 is an explanatory cross-sectional view of a processing container using a facing-type ground electrode.

FIG. 6 is an explanatory cross-sectional view of a processing vessel using a facing-type ground electrode having a slope portion inside.

FIG. 7 is an enlarged sectional view of a main part near an upper electrode and a susceptor when a permanent magnet is used as plasma diffusion preventing means.

FIG. 8 is a perspective view of the permanent magnet in FIG. 7;

FIG. 9 is a bottom view of the insulating member showing a state of arrangement of the permanent magnets in FIG. 7;

FIG. 10 is an explanatory diagram showing a state of a magnetic pole arrangement of the permanent magnet of FIG. 7;

11 is an explanatory sectional view showing a state where a magnetic material is attached to the permanent magnet of FIG. 7;

FIG. 12 is an explanatory view showing another arrangement of the magnetic poles of the permanent magnet.

FIG. 13 is an explanatory sectional view of a contact hole formed by etching according to a conventional technique.

FIG. 14 is a graph showing a state of output modulation of high frequency power applied in another embodiment.

FIG. 15 is an explanatory sectional view of a contact hole formed according to an embodiment of the present invention.

FIG. 16 is an explanatory diagram of another embodiment of the present invention in the RIE mode.

FIG. 17 is an explanatory diagram of another embodiment of the present invention in the PE mode.

FIG. 18 is an explanatory view of an etching apparatus of a second embodiment having a configuration for applying high-frequency powers having different frequencies to upper and lower opposed electrodes.

FIG. 19 is an explanatory view of a main part of the etching apparatus of FIG. 18;

FIG. 20 is an explanatory diagram showing a state where the outer peripheral edges of the ground electrode on the upper electrode side and the ground electrode on the lower electrode side do not overlap.

FIG. 21 is a graph showing a relationship between a gap length between upper and lower opposing electrodes, an etching rate, uniformity, and plasma stability.

FIG. 22 is an explanatory diagram showing a configuration of a conventional matching device.

FIG. 23 is an explanatory view of another embodiment in which the gap length between the upper and lower opposed electrodes is made variable.

FIG. 24 has a high-pass filter and a low-pass filter
1 is an explanatory sectional view of an etching apparatus to be used.

FIG. 25 is a graph showing the relationship between the incident ion energy to the wafer and the number of incident ions for each frequency of the relative low-frequency power.

FIG. 26 is a cross-sectional explanatory view of an etching processing apparatus for explaining a processing container deterioration prevention technique applicable to the embodiment of the present invention.

FIG. 27 is an explanatory cross-sectional view of the etching apparatus of FIG . 26 as viewed from above.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Etching processing apparatus 2 Processing container 5 Susceptor 15 Focus ring 21 Upper electrode 27 Ground electrode 51, 52 High frequency power supply 55, 56 Phase detection means 57 Phase controller W Wafer

──────────────────────────────────────────────────続 き Continued on the front page (31) Priority claim number Japanese Patent Application No. 6-252963 (32) Priority date September 20, 1994 (September 20, 1994) (33) Priority claim country Japan (JP) (31) Priority claim number Japanese Patent Application No. 7-29940 (32) Priority date January 25, 1995 (Jan. 25, 1995) (33) Priority claim country Japan (JP) Preliminary examination (72) Invention Person: Tsuchiya Hiroshi 2381, Kita-Shimojo, Fujii-machi, Nirasaki-shi, Yamanashi Prefecture Inside Tokyo Electron Yamanashi Co., Ltd. Inventor Yukio Naito 2381-1, Kita-Shimojo, Fujii-machi, Nirasaki, Yamanashi Prefecture Inside Tokyo Electron Yamanashi Co., Ltd. 72) Invention Person Ryu Nonaka 2381 Kita Shimojo, Fujii-machi, Nirasaki City, Yamanashi Prefecture Inside Tokyo Electron Yamanashi Co., Ltd. (72) Inventor Keizo Hirose 1238-2, Kita Shimojo, Fujii-machi, Nirasaki City, Yamanashi Prefecture Tokyo Electron Yamanashi Co., Ltd. Person Yoshio Fukasawa 2381-1, Kita-Shimojo, Fujii-machi, Nirasaki-city, Yamanashi Prefecture Inside the Tokyo Electron Yamanashi Co., Ltd. No. 2381 Kita-Shimojo, Fujii-machi, Nirasaki City, Yamanashi Prefecture, Tokyo Electron Yamanashi Co., Ltd. (56) References JP-A-62-69621 (JP, A) JP-A-5-251394 (JP, A) Hei 5-291155 (JP, A) JP-A-7-106097 (JP, A) JP-A-3-4528 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21 / 3065 C23C 16/507

Claims (2)

(57) [Claims] 1. A plasma is generated by high frequency power between a first electrode and a second electrode provided in a processing chamber so as to face each other, and a plasma atmosphere is applied to an object to be processed in the processing chamber. A plasma processing apparatus configured to perform processing under the following conditions: a cylindrical ground electrode disposed so as to surround a space region between the electrodes in the processing chamber from a side portion; A plasma processing apparatus characterized in that the circumference is in a form protruding inward. 2. A plasma is generated by high-frequency power between a first electrode and a second electrode provided to face each other in a processing chamber, and a plasma atmosphere is applied to an object to be processed in the processing chamber. In a plasma processing apparatus configured to perform processing under the following conditions, a substantially annular third electrode is provided near the outer periphery of the first electrode, and a substantially annular third electrode is provided near the outer periphery of the second electrode. Fourth electrode is provided, and the third electrode and the fourth electrode are respectively grounded. Further, the third electrode and the fourth electrode are disposed so as to face each other over the entire circumference, and the third electrode and the fourth electrode are connected to each other. The electrode 4 has an inner surface that forms a slope.
The cross-section has a substantially triangular shape to form
A plasma processing apparatus.