JPH0813169A - Plasma processing device - Google Patents

Abstract

(57) [Abstract] [Purpose] 1 × 10 ^-3 Tor by combining the inductive coupling due to the inductance of the antenna member and the capacitive coupling between the antenna member and the processing container or the susceptor.
It is an object of the present invention to provide a plasma processing apparatus capable of generating plasma even at a low pressure of r or less. In a plasma processing apparatus for performing plasma processing on an object to be processed W placed on a susceptor 20 in an airtight processing container 4, an antenna member is provided in a position facing the susceptor in the processing container. 6 is arranged, and a high frequency power source 8 for plasma generation is connected to this antenna member. As a result, plasma can be generated even under a high vacuum of 1 × 10 ⁻⁶ Torr, and highly anisotropic plasma treatment can be performed. Moreover, since the space between the antenna member and the susceptor can be made small, the plasma generation efficiency can be improved.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a plasma processing apparatus.

[0002]

2. Description of the Related Art Generally, in a part of a semiconductor manufacturing process, for example, a plasma processing apparatus is used to perform various kinds of processing such as plasma etching on a semiconductor wafer as an object to be processed. In this type of plasma processing apparatus, for example, two flat plate-shaped electrodes are positioned in parallel in a processing container, and a high frequency voltage of 13.56 MHz, for example, is applied between them by a high frequency power source for plasma generation. As a result, plasma is generated, and the surface of the wafer is subjected to processing such as etching.

In the plasma generated between the parallel plate electrodes as described above, the electric field is an alternating electric field directed from one electrode to the other electrode, so that electrons are attracted along this electric field and collide with gas molecules. The active species generated by this,
The active species collide with the surface of the wafer to perform etching.

[0004]

By the way, high density of semiconductor products, for example, in DRAM, 4M and 16M are taken as examples.
With the shift from the bit storage capacity to the 64M and 256M bit storage capacities, finer fine processing is required. Therefore, plasma is generated in a low pressure region to improve the directionality of etching and the like. Is required.

However, in the parallel plate electrode type plasma processing apparatus as described above, an electric field is generated between both electrodes but a magnetic field is generated due to the coupling circuit formed by the electrostatic capacitance formed between the electrodes. It was difficult to do so, and therefore the confinement of the plasma by the magnetic field was not sufficient, so the pressure region of the plasma was 1 × 10 ⁻² Torr or more, and the pressure was relatively high. Therefore, the active species during etching are likely to be scattered by gas molecules and the directionality is deteriorated,
There is a problem in that etching processing having a sharp shape, which is required in a 64 M or 256 M bit DRAM or the like, cannot be performed.

Further, if the etching pressure is high as described above, the by-products generated by the etching cannot be sufficiently discharged, so that not only the etching shape is further deteriorated but also the etching rate is deteriorated. There was also a problem. Also, plasma CVD is used to deposit, for example, an interlayer insulating film using a plasma processing apparatus.
When processing is performed, the wafer is heated to a relatively high temperature, for example, about 400 ° C., but the electrostatic chuck that adsorbs and holds the wafer on the susceptor is not generally high in heat resistance, for example, the maximum. Since a polyimide resin having a heat-resistant temperature of about 150 ° C. is used, there is a problem that the process temperature cannot be raised so high and plasma power cannot be applied sufficiently.

The present invention focuses on the above problems,
It was created to solve this effectively. An object of the present invention is to combine the inductive coupling due to the inductance of the antenna member and the capacitive coupling between the antenna member and the processing container or the susceptor to obtain 1 × 10 ⁻³ Tor.
It is an object of the present invention to provide a plasma processing apparatus capable of generating plasma even at a low pressure of r or less.

[0008]

In order to solve the above-mentioned problems, a first invention is a plasma treatment for subjecting an object to be treated placed on a susceptor in an airtight treatment container to a plasma treatment. In the apparatus, an antenna member is arranged in a position facing the susceptor in the processing container, and a high frequency power source for plasma generation is connected to the antenna member.

In order to solve the above-mentioned problems, a second aspect of the present invention is a plasma processing apparatus for performing a plasma process on an object to be processed placed on a susceptor in an airtight processing container, wherein the processing container is a container. The ceiling part is formed of a dielectric that transmits radio waves, at least the inner surface side of the ceiling part is formed of a ceramic material, and an antenna member is arranged on the upper surface side of the ceiling part so as to face the susceptor. A high frequency power source for plasma generation is connected to the antenna member. A for this ceramic material
It is preferable to use 1N, and quartz or AlN can be used as the dielectric.

As the electrostatic chuck for attracting and holding the object to be processed on the susceptor, an electrostatic chuck formed by coating a conductive thin film with SiC can be used. Also,
A bias voltage source is connected to this susceptor and 1 MH
A bias voltage having a frequency within the range of z to 10 MHz can be applied. Further, a cold trap for removing reaction products can be provided in the vacuum exhaust system for evacuating the inside of the processing container.

[0011]

Since the first aspect of the invention is configured as described above, a high-frequency power source is connected to the antenna member arranged in the processing container so as to face the susceptor, and a high-frequency voltage is applied to the antenna member. Plasma is generated in the processing container due to the action of radio waves and the electric field between the antenna member and the processing container. This plasma is generated even in a low pressure state of 1 × 10 ⁻³ Torr or less, which could not be generated in the conventional apparatus. Therefore, for example, the directionality during etching can be improved and etching with excellent anisotropy can be performed. Becomes In particular, since the antenna member is housed in the processing container, the antenna member can be provided as close as possible to the object to be processed, and power can be efficiently applied to increase the density of plasma and the efficiency of plasma generation. You can

In the second invention, the antenna member is arranged on the upper surface side of the ceiling portion of the processing container, and the electric wave from this is transmitted to the ceiling portion and introduced into the processing container. By the action, a dense plasma can be generated. Therefore, plasma processing, for example, plasma CVD processing can be efficiently performed.

Further, since at least the inner surface of the ceiling exposed to the plasma is made of an AlN material, the AlN material has higher heat resistance and corrosion resistance than, for example, quartz or the like, so that the heat resistance and the corrosion resistance are improved. Not only
The amount scraped during cleaning can be greatly suppressed.

Further, when an electrostatic chuck coated with SiN is used, it has excellent heat resistance, so that it is possible to supply sufficient plasma power and perform plasma CVD processing at a high process temperature. it can. In addition, SiC
By using the chuck, the potential difference between the susceptor or the object to be processed with respect to the plasma is increased and the attraction of ions is strengthened. As a result, the vertical deposition efficiency at the time of CVD is improved and the occurrence of voids can be suppressed. Particularly, at this time, by applying a bias voltage having a frequency within the range of 1 MHz to 10 MHz to the susceptor, it is possible to further suppress the generation of the void.

Further, by providing a cold trap in the vacuum exhaust system, it is possible to remove the reaction product produced during the plasma CVD process even if it is contained in the exhaust gas. Therefore, for example, a vacuum pump or the like. Can be prevented from being adversely affected.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the plasma processing apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. 1 is a sectional view showing an example of a plasma processing apparatus according to the first invention, and FIG. 2 is a plan view showing an antenna member of the apparatus shown in FIG. In this embodiment, a case where the plasma processing apparatus according to the present invention is applied to a plasma etching apparatus will be described.

The plasma etching apparatus 2 is characterized in that an antenna member 6 is provided inside the ceiling of the processing container 4, and a high frequency power source 8 for plasma generation is connected to both ends of the antenna member 6. That is, the processing container 4 is formed into a cylindrical body with a conductive material such as aluminum or stainless steel, and the ceiling portion 10 and the bottom portion 12 are also formed with a conductive material such as aluminum or stainless steel. The processing container 4 is airtightly attached to the opening at the lower end of the processing container 4 via a seal member 14 to hermetically seal the inside. Therefore, a closed processing chamber 16 is formed in the processing container 4.

When the side wall, the ceiling portion 6 and the bottom portion 12 of the processing container 4 are made of aluminum, an alumite treatment is applied in order to apply a corrosion resistant coating to the inner surface thereof. The processing container 4 is electrically grounded. On the side wall of the processing container 4, for example, a loading / unloading port 1 for loading / unloading a semiconductor wafer W as an object to be processed.
6 is formed, and the carry-in / out port 16 is provided with a gate valve 17 that can be opened and closed in an airtight manner. A processing gas supply pipe 78 for introducing a processing gas, such as HF gas, from a processing gas source (not shown) into the processing chamber 16 through a mass flow controller (not shown) on the side wall of the processing container opposite to the gate valve 17. Is provided. The processing gas supply pipe 78 is preferably made of a semiconductor such as quartz or silicon so that it does not absorb high frequency power. In addition, at the bottom of the processing container 4,
A gas exhaust pipe 18 is connected so that the inside of the processing container 4 can be evacuated by a vacuum pump (not shown).

A disk-shaped susceptor 20 for mounting a semiconductor wafer W as an object to be processed is arranged in the processing container 4, and an electrostatic chuck (not shown) or the like is mounted on the mounting surface. A wafer holding member is provided to surely suck and hold the wafer by Coulomb force. The susceptor 20 is connected through an insulated wiring 22 to a parallel circuit composed of a high frequency power source 22 and a double switch 24 which is opened and closed in reverse, and grounds the susceptor 20 or supplies high frequency power to this. It is possible to select whether to apply.

A temperature adjusting device for adjusting the temperature of the semiconductor wafer W, for example, a ceramic heater 26 is provided below the susceptor 20, and a coolant 28 such as liquid nitrogen is provided below the ceramic heater 26. A cooling jacket 30 that can be circulated is provided. By combining the cooling jacket 30 and the ceramic heater 26, the wafer temperature can be set to an arbitrary temperature within a range from a low temperature range close to the temperature of liquid nitrogen to a high temperature range. It can be set.

The antenna member 6, which is a feature of the present invention and is arranged so as to face the susceptor 26 with a predetermined gap therebetween, is a circular section member made of a conductive member such as gold or copper as shown in FIG. As described above, for example, the antenna portion 32 is formed by spirally winding two turns in a plane, and the wiring 3 is formed from the inner peripheral end 32A and the outer peripheral end 32B of the antenna portion 32.
4, a high frequency power source 8 for plasma generation and a matching box 36 for adjusting the capacity for stable plasma generation are connected between the wirings 34. Therefore, an electric wave is emitted from the antenna member 6 toward the processing chamber 16 therebelow, and an electric field is generated between the antenna member 6 and the side wall of the processing container or the susceptor 20, whereby the so-called inductive coupling method is used. Plasma is generated in the processing chamber 16.

In this case, the antenna member 6 is not limited to the one having a circular cross section, and a member having a wide plate member having a rectangular cross section wound can be used. In addition, the antenna member 6
The number of windings is not limited to two turns, and one turn as shown in FIG. 3 or one wound three or more turns in a spiral shape can be used. In any case, the diameter is The diameter is set to be equal to or larger than the diameter of the wafer to ensure the uniformity of plasma density over the entire wafer surface. The frequency of the high frequency power source 8 for plasma generation is set within the range of 1 to 200 MHz, preferably about 2 MHz, 13.56 MHz or 56 MHz.

The entire antenna member 6 arranged in the processing container 4 is covered with an antenna protection cover 38 made of a dielectric material such as quartz or ceramic or an insulating material. Specifically, the antenna protection cover 38 is configured as a disk-shaped container having a size capable of accommodating the entire antenna member 6, and an inert gas for introducing an inert gas such as argon gas is provided in the center thereof. The introduction pipe 38 is provided so as to vertically penetrate to support the antenna protection cover 38. It is preferable that the inert gas introducing pipe 39 is made of a semiconductor such as quartz or silicon so that the high frequency power is not absorbed thereby.

An upper side of the inert gas introducing pipe 39 is provided in a through hole provided at the center of the ceiling portion 10 of the processing container 4 in an airtight manner through, for example, an insulating seal member 40. The introduction pipe 39 is connected to an inert gas source via a mass flow controller (not shown). Therefore, the antenna protection cover 38 is supported by the inert gas introducing pipe 39. Of course, the mounting state of the antenna protection cover 38 is not limited to this.

The thickness L1 of the antenna protection cover 38
Is capable of preventing the heavy metal from jumping out into the processing chamber 16 due to the sputtering of the antenna member 6 housed inside by the plasma, and moreover, the radio wave emitted from the antenna member 6 propagates into the processing chamber 16 without changing its shape. The thickness to be obtained, for example, about several mm is set.

The diameter of the processing container 4 is set to about 50 cm when the object to be processed is an 8-inch wafer, for example.
At that time, the distance L2 between the surface of the susceptor and the lower surface of the antenna protection cover 38 is set within the range of 30 to 150 mm.
In this way, the antenna member 6 is housed in the processing container 4,
By reducing the distance between this and the susceptor 20, it becomes possible to efficiently generate plasma with less electric power.

Here, it is conceivable that the antenna member 6 is provided not on the inside of the housing container 4 but on the outside thereof, for example, on the upper surface side of the ceiling portion 10, but in this case it is not so preferable from the following points. That is, as described above, the antenna member 6
Is provided in the outside air on the outer surface of the ceiling portion 10, the problem of heavy metal contamination by the material forming the antenna member during plasma processing can be solved, but the radio waves generated from the antenna member 6 can be efficiently transmitted into the processing chamber 16. In order to propagate to the above, the constituent material of the ceiling part must be changed from a conductive material such as aluminum or stainless steel to a dielectric such as a quartz plate.

In this case, the quartz plate must be set to have a thickness of several cm so as to withstand the pressure difference between the inside and the outside, and depending on the wafer size, in the case of a 12-inch wafer processing container, This diameter must be set to about 50 cm, which makes the quartz plate very expensive.

Even if the quartz plate is made pressure resistant as described above, the outer surface of the quartz plate is in contact with the atmosphere at room temperature, and the inner surface is in contact with the atmosphere in the processing chamber having a relatively high temperature. There is a possibility that damage due to the temperature difference between
In particular, when a harmful treatment gas such as SiH ₄ is used, there is a risk that this gas may leak into the atmosphere. Furthermore, by disposing the antenna member outside the processing container, not only the distance between the antenna member and the wafer becomes considerably large, but also high-frequency power is supplied through the quartz plate, so that it is applied. There is a risk that the high frequency power will be insufficient or the energy loss will increase, making it impossible to efficiently apply the RF power.

Further, since the antenna member is arranged outside the processing container, shield measures must be taken to prevent the leakage of electromagnetic waves to the periphery of the apparatus, which complicates the structure of the apparatus itself. Further, since the antenna member is provided outside the ceiling part, both the processing gas for plasma processing and the inert gas have to be introduced into the processing chamber from the side wall part, so that the etching process and the CVD process can be performed uniformly on the wafer surface. May not be able to secure sufficient sex. From the above points, in the present invention, the antenna member 6 is installed in the processing container in an insulated state.

Next, the operation of this embodiment configured as described above will be described. First, the semiconductor wafer W is accommodated in the processing chamber 16 by a transfer arm (not shown) via the gate valve 17, and is mounted on the mounting surface of the susceptor 20 to be suction-held by the Coulomb force of the electrostatic chuck.

The inside of the processing chamber 16 is evacuated by a vacuum pump (not shown) connected to the gas exhaust pipe 19,
To the inside of the processing chamber 16, a processing gas supply pipe 18 provided on a side wall and an inert gas introduction pipe 39 provided through the central portion of the ceiling portion 10 in an airtight manner are provided, respectively.
By supplying an inert gas such as r gas, for example, 1 × 10 ⁻³ To
The pressure is maintained at a considerably low pressure of about rr, and at the same time, a high frequency of 13.56 MHz, for example, is applied to both ends of the antenna member 6 from the high frequency power source 8 for plasma generation.

Then, a radio wave is emitted toward the entire lower surface due to the inductive action of the inductance component of the antenna member 6, and at the same time when the RF power is applied to the susceptor 20 from the high frequency power source 22, this antenna member 6 is also used. An alternating electric field is generated by the action of the capacitive component between the susceptor 20 and
As a result, the processing gas or Ar gas is activated and ionized in the processing chamber 16 to generate plasma, and very highly anisotropic etching can be performed on the wafer surface by the active species generated by the plasma discharge excitation. it can. In this case, RF power may be applied to the susceptor 20 as described above, or it may be grounded.

The anions in the active species move to the susceptor 20 side while spirally swirling due to the action of the electric wave and the electric field, and the anions can move as compared with the conventional parallel plate electrode type device. The distance becomes longer, and during this period, many ions collide with gas molecules and many ions are generated. Therefore,
As a result, the plasma generation efficiency is improved and the etching rate can be improved.

The plasma is 1 × 10 ^-3 Torr.
Since it is generated even under a fairly low pressure within a range of up to 1 × 10 ⁻⁶ Torr, scattering of active species during etching is small and the directionality is uniform, and therefore, as described above, the anisotropy is high. That is, it is possible to perform etching processing having a sharp shape, for example, 64M or 256M bit DRAM.
It is possible to perform the fine processing required for the above.

In particular, in this embodiment, the antenna member 6
Is accommodated in the processing chamber 16, the distance L2 between the wafer and the wafer W is shortened, and the radio wave emitted from the antenna member 6 is immediately irradiated to the gas in the processing chamber 16 with almost no attenuation. Since this is excited, the plasma generation efficiency can be greatly increased, and the plasma density can be increased. In this case,
Since the entire antenna member 6 is covered with the antenna protection cover 38, the antenna member 6 is not sputtered by active species and the wafer is not contaminated with heavy metals.

Further, by accommodating the antenna member 6 in the processing container 4, the ceiling 10 of the processing container 4 becomes empty. Therefore, a gas introduction pipe such as an inert gas introduction pipe 39 is provided in this portion, and the inside of the processing chamber 16 is provided. The gas can be directly introduced into the central part of the wafer, and therefore, the gas can be evenly distributed over substantially the entire wafer surface in the processing chamber 16 to uniformly generate plasma, and the in-plane uniformity is improved. Can be made.

Further, in comparison with the case where the antenna member 6 is arranged outside the processing container 4 and the ceiling portion 10 is made of thick disk-shaped quartz, the quartz plate is eliminated according to the present embodiment. Can be integrated with the side wall by using, for example, aluminum, so that not only the cost can be significantly reduced, but also the problems of damage and leakage of harmful gas caused by using the quartz plate can be solved. Further, since the radio wave generated from the antenna member 6 is shielded by the processing container 4 made of a conductive material, it is not necessary to separately take special shield measures.

In the above embodiment, the case where the planar antenna portion 32 formed by spirally winding a conductor is used as the antenna member 6 has been described, but instead of this, FIG. 4 is shown. Such a tubular coil portion 42 may be used. Although ceramic heaters, cooling jackets, and the like are omitted in the illustrated examples of the embodiments described below, it goes without saying that these may or may not be provided. In this embodiment, a thick wire made of a conductive material such as copper is spirally wound a plurality of times, three times in the illustrated example, to form a tubular coil portion 42. In this case, the diameter of the coil portion 42 is set to be substantially the same as or slightly larger than the diameter of the wafer W to be processed so that the plasma stands substantially uniformly in the wafer surface.

The tubular antenna member 32 is
The ceiling portion 10 of the processing container 4 is housed in the antenna housing projection 10A formed by protruding upward in a cylindrical shape, and the coil portion 4 is housed.
The coil portion 42 is arranged so that the winding direction of 2 is orthogonal to the surface of the wafer W.

The entire coil portion 42 is also covered with a cylindrical ring-shaped antenna protection cover 38 made of a dielectric material such as quartz and having a hollow interior. At the center of the cylindrical ring-shaped antenna protection cover 38, the lower end is opened to form a gas ejection port 43, the upper end is closed, and the lower end of the inert gas introducing pipe 39 is connected to this portion. It supports the entire member 6. The configuration of the other parts is the same as that of the device shown in FIG.

In this embodiment, the inert gas introducing pipe 3 is used.
The inert gas introduced through 9 is excited by radio waves from the antenna member 6 into plasma while flowing down the central space of the cylindrical antenna member 6, and flows out from the gas ejection port 44 at the lower end. Occasionally, it comes into contact with the process gas and activates it to form active species. Also in this case, plasma is generated even under a fairly low pressure within the range of 1 × 10 ⁻³ Torr to 1 × 10 ⁻⁶ Torr, and not only a highly anisotropic sharp etching process can be performed, Plasma can be generated efficiently, as shown in FIG.
It is possible to exert the same effect as that of the first embodiment shown in FIG.

Although the above-described first and second embodiments have been described with respect to the case where the planar antenna member and the tubular coil antenna member are individually provided, as shown in FIG. 5, these planar antenna members are provided. You may comprise so that a member and a cylindrical coil-shaped antenna member may be combined.

That is, in the third embodiment, the flat plate antenna portion 32 as shown in FIG. 1 is arranged at the upper end of the cylindrical coil portion 42 as shown in FIG. 4 is covered with an antenna protection cover 38 made of quartz or the like as shown in FIG. Further, separate high-frequency power supplies 8A and 8B for plasma generation are connected to the respective ends of the flat plate-shaped antenna section 32 and the cylindrical coil section 42 via matching boxes 36A and 36B.

In this case, the frequency of each of the high frequency power supplies 8A and 8B can be arbitrarily set within the range of 1 MHz to 200 MHz, for example, 2 MHz and 13.56 MHz, or 50.
Any combination such as a combination of MHz and 13.56 MHz can be selected. Alternatively, the two flat plate-shaped antenna members 32 and the cylindrical coil member 42 may be connected in series, and one high-frequency power source for plasma generation may be applied to the whole. Even when the flat plate-shaped antenna member 32 and the cylindrical coil member 42 are combined in this way, the same operational effects as those of the first and second embodiments can be exhibited.

In particular, when the flat plate-shaped antenna member is used alone, as shown in FIG.
In the case of D processing, the processing rate curve 44 such as the CVD film forming rate is slightly lower at the center of the wafer and gradually decreases toward the peripheral edge of the wafer with the peripheral portion as a peak, and strictly speaking, it becomes uniform. is not. Therefore, by using an antenna member composed of the tubular coil portion 42 in combination as an auxiliary antenna member, the rate decrease of the wafer peripheral portion is corrected and the processing rate curve 44 becomes a substantially straight line state as shown by the one-dot chain line. Further, for example, in-plane uniformity of etching can be further achieved.

In the above-mentioned three embodiments, first,
The antenna member is formed, and the whole of the antenna member is housed in the container-shaped antenna protection cover 38 so as to cover the antenna member. However, the present invention is not limited to this. For example, as shown in FIGS. The antenna protection cover 38 may be configured by directly surface-coating the flexible wire itself with a protective layer 46 made of a dielectric material such as quartz and having a predetermined thickness.

The arrangement of the antenna members 6 shown in FIGS. 7, 9 and 10 corresponds to the antenna members shown in FIGS. 1, 4 and 5, respectively. FIG. 8 is an enlarged cross-sectional view of the antenna member 38 shown in FIG.
The antenna member 6 whose surface is coated with a protective layer 46 of a certain degree is suspended and supported by a support member 48 on the lower surface of the ceiling portion 10 of the processing container 4. The thickness of the protective layer 46 is set to a thickness that can prevent heavy metal contamination due to sputtering as described above. Such a protective layer 46
Can be formed, for example, by immersing the antenna element wire in a solution of silicon oxide and growing the crystal.

Further, in the apparatus example shown in FIGS. 9 and 10, the inert gas introducing pipe 39 provided at the center of the ceiling portion 10 is used.
The lower end of the introduction pipe 39 is made of, for example, quartz so as not to be in a turbulent state due to the irregularities of the spiral coil portion 42 when the introduced inert gas flows down in the antenna housing projection 10A. A cylindrical plasma guide tube 50 is connected, and the rectified plasma flows into the processing chamber 16 from the gas ejection port 43 at the lower end of the guide tube 50 as in the case shown in FIGS. 4 and 5. become.

Further, in each of the embodiments described above, the inert gas from the inert gas introducing pipe 39 was directly introduced into the processing container, but the present invention is not limited to this, and as shown in FIGS. 11 and 12, for example. As shown, a well-known shower head 52 made of, for example, quartz may be provided at the tip of the inert gas introducing pipe 39. The shower head 52 has a single or a plurality of rectifying plates 56 having a large number of ventilation holes 54, and is adapted to uniformly supply the inert gas over the entire wafer surface.

In the embodiment shown in FIG. 11, the shower head 52 is directly provided on the lower surface of the ceiling portion 10 of the processing container 4, and the lower surface of the shower head 52 has a protective layer as shown in FIG. The structure in which the one-turn antenna member 6 directly coated with 46 is arranged is shown. Further, in the embodiment shown in FIG. 12, the ceiling portion 10
On the lower surface of the antenna protection cover 38 similar to that shown in FIG.
The antenna member 6 accommodated therein is arranged, and the shower head 52 is arranged on the lower surface thereof.

These two embodiments can also exhibit the same effects as the previous embodiments. In particular, by using the shower head 52, the inert gas can be supplied over the entire area of the wafer surface, and the in-plane uniformity of plasma processing can be further improved.

In each of the above embodiments, the high frequency power source for plasma generation is applied to both ends of each antenna member, but the present invention is not limited to this, and the high frequency power source is applied to only one end of each antenna member. The voltage may be applied and the other end may be an open end. The number of windings of the antenna member is not limited to those in the above-described embodiments, and the number of windings may be increased if necessary.

In the above-mentioned embodiment, the plasma etching apparatus having the antenna member arranged in the processing container has been described as an example. However, in the next second invention, a plasma CVD apparatus having the antenna member arranged outside the processing container is taken as an example. To explain.

FIG. 13 is a sectional view showing a plasma processing apparatus (plasma CVD apparatus) according to the second invention, FIG. 14 is a plan view showing an antenna member, FIG. 15 is an exploded view showing an electrostatic chuck, and FIG. 16 is cold. It is sectional drawing which shows a trap.
As shown in FIG. 13, the plasma CVD apparatus 60 has a processing container 62 made of, for example, aluminum, which is formed in a bottomed rectangular shape or a cylindrical shape with an open ceiling. In the processing container 62, a susceptor 64 made of, for example, aluminum as a lower electrode on which the semiconductor wafer W is mounted is provided on the bottom of the container via an insulating member 66. An electrostatic chuck 72 connected to, for example, a high-voltage DC source 68 via an open / close switch 70 is provided on the mounting surface that is the upper surface of the susceptor 64, and the wafer is attracted and held by a Coulomb force. There is.

Specifically, as shown in FIG. 15, the electrostatic chuck 72 has a disk-shaped or thin-film conductive thin film 76 made of, for example, copper and a SiC thin film 78 having insulating properties from above and below. , 78 so as to be sandwiched so as to be sandwiched therebetween. SiC thin film 78, 78
Is slightly larger than the diameter of the conductive thin film 76, and the thin film peripheral edge is completely covered with the SiC thin film. Then, the power supply line 80 of the high voltage DC source 68 is connected to the conductive thin film 76. This makes it possible to improve the heat resistance of the electrostatic chuck and the vertical deposition efficiency during CVD, as will be described later.

A heating means such as a ceramic heater 82 is embedded in the susceptor 64, and a heating power source 84 is connected to the heater via an open / close switch 86. The open / close switch 88 and a high frequency bias voltage source 90 are connected to the susceptor 64 via a power supply line 92, and a bias voltage is applied to the susceptor 64 during plasma CVD processing. In this case, the frequency of the bias voltage is set to 1 M in consideration of the electric field transparency of the electrostatic chuck 72 to the SiC thin film 78 and the self-bias effect.
It is set within the range of Hz to 10 MHz, preferably near 2 MHz.

A vacuum exhaust system 96 having a vacuum pump 94 is connected to the bottom of the processing container 62, and a reaction product contained in the exhaust gas is trapped in the middle of the vacuum exhaust system 96. A cold trap 98 for removing it is provided. Specifically, the cold trap 98 is provided on the upstream side of the vacuum pump 94 as shown in FIG. 16 and is attachable to and detachable from the pipe 96A of the vacuum exhaust system 96, for example, a trap box made of aluminum. Has 100.

In this box 100, a plurality of baffle plates 102 extending alternately from opposite side walls.
Boxes A, 102B, 102C are provided.
The trap passage 108 having a meandering or zigzag shape is formed from the introduction port 104 of 00 to the discharge port 106. As a result, the reaction product contained in the exhaust gas passing through the trap passage 108 is attached to the surface of the baffle plate and trapped. Here, in order to improve the trap efficiency, a large number of pipe-shaped refrigerant passages 110 are provided on the back surface of each baffle plate 102A to 102C, and the temperature of the baffle plate is increased by flowing a refrigerant, for example, cooling water. To lower the trap efficiency.

On the other hand, the processing container is grounded to have a zero potential, and a gate valve G1 that is opened and closed airtightly when the wafer is loaded and unloaded is provided on the side wall of the container. At least the side wall of the processing container 24 is made of pure aluminum having a considerably high purity, for example, a purity of about 99% or more, and the inner wall surface thereof is not subjected to hard alumite treatment or the like, and the aluminum is exposed. There is. As a result, metal pollutants such as Mg are not released even when subjected to plasma sputtering.

A gas introduction nozzle 112 for introducing a processing gas is provided through the side wall of the processing container 62, and a gas passage 114 is connected to the nozzle 112. A film forming process gas supply source 116 for supplying a film forming process gas is connected to the gas passage 114. As the processing gas, a mixed gas of silane, O ₂ and Ar, or TEOS or O which is an organic film forming gas.
A mixed gas of ₂ and Ar or the like is used. Therefore, the supply source 116 is provided with a plurality of cylinders 118 for storing these used gases, and the required amount of the mass flow controller 1 is set.
The flow rate is controlled by 20 to supply the gas.

On the other hand, at the opening of the ceiling of the processing container 62, a plate-shaped ceiling 122 made of a dielectric material, for example, a ceramic material, which can transmit electromagnetic waves is hermetically sealed via a sealing member 124 such as an O-ring. It is provided in. The thickness of the ceiling portion 122 is thick enough to withstand the vacuum pressure in the processing container 62, and is set to, for example, about 20 mm.

Specifically, as this ceramic material,
It is preferable to use an AlN material having higher heat resistance, durability against spatter, and corrosion resistance than quartz. In this case, the entire ceiling 122 may be made of an AlN material, or most of the ceiling 122 may be made of quartz or another ceramic material, and the ceiling wall inner wall surface side that has been exposed to plasma Only, the AlN layer having a predetermined thickness may be coated.

On the upper surface of the ceramic ceiling part 122, as shown in FIG.
An antenna member 126 made of a conductor wound in a spiral shape, for example, copper is provided. Then, between the center end and the outer peripheral end of the antenna member 126, for example, 13.56.
High frequency power supply system 1 with a high frequency power supply 128 of 1 MHz interposed
30 is connected, and a matching circuit 132 for improving the high frequency application efficiency is provided in the middle of the power feeding system 130.

Therefore, an electromagnetic wave generated by applying a high frequency voltage to the antenna member 126 passes through the ceramic ceiling 122 and reaches the processing space S where the processing gas is excited to generate plasma. Become. Here, the shape of the antenna member 126 is not limited to a spiral shape of 2 to 3 turns, and may be set to a ring shape of 1 turn or a spiral shape of 4 turns or more.
The sectional shape of 6 is not limited to the circular shape as shown in the drawing, but may be set to a rectangular shape, for example.

The entire antenna member 126 is covered with a mesh-shaped shield 134 made of, for example, a metal net in order to prevent electromagnetic waves from leaking to the outside, and the shield 134 is grounded.

Next, the operation of this embodiment configured as described above will be described. First, the semiconductor wafer W is mounted on the mounting surface on the upper surface of the susceptor 64, and the electrostatic chuck 7
By applying a high-voltage DC voltage to the second conductive thin film 76, the wafer is securely attracted and held by the Coulomb force.

Next, by driving the vacuum exhaust system 96, the processing gas for film formation, for example, a mixed gas of silane, oxygen and Ar is supplied from the gas introduction nozzle 112 while maintaining the inside of the processing container 62 at a predetermined process pressure. The wafer W is maintained at a predetermined process temperature, for example, about 400 ° C. by introducing and driving the ceramic heater 82.

By applying a high frequency voltage of, for example, 13.56 MHz from the high frequency power source 128 to the antenna member 126, a radio wave is radiated from the antenna member 126 and the radio wave passes through the ceiling part 122 made of AlN. To the processing space S. Further, an electric field is generated between the antenna member 126 and the side wall of the processing container or the susceptor 64, and the processing gas is turned into plasma by the action of these electric fields and radio waves, and activated species are generated by the plasma discharge excitation to cause a reaction. Be promoted. The reaction product SiO ₂ generated at this time is deposited on the surface of the wafer.
The plasma density generated at this time is as a result of the inductive coupling action,
Compared with the conventional parallel plate method, it is considerably higher,
As a result, the production of active species will be promoted.

Here, the ceiling 122 exposed to the plasma
Uses an AlN material that has excellent heat resistance and corrosion resistance, so the process temperature can be maintained at a sufficiently high temperature and the temperature at which the aluminum wiring on the wafer does not melt, for example, up to 600 ° C
Can be as high as a degree. Therefore, the deposition efficiency of film formation can be maintained high.

Further, since the inner side surface of the ceiling part 122 is heated to the process temperature and the upper side surface is at approximately room temperature,
Although the temperature gradient between the upper side surface and the lower side surface becomes considerably large, as described above, since the AlN material has considerably higher heat resistance than quartz or the like, the possibility of this damage can be greatly suppressed. In other words, as compared with the case where a quartz material is used for the ceiling part, the use of the AlN material is economical because the heat resistance can be reduced to the extent that the heat resistance is good.

Further, since the AlN material is superior in durability as compared with quartz or the like, the inner side surface thereof is very little scraped off even if it is sputtered by the ions ejected from the plasma in the processing space. In addition, generation of particles can be suppressed as compared with the case of quartz.

Further, since the reaction product (SiO ₂ ) adheres to the inner surface of the ceiling 122 and the like by repeating the plasma CVD process, the cleaning operation is performed regularly or irregularly. In this case, the processing container 62
Supplies a cleaning gas consisting of CF _3, etc. for scraping the SiO ₂ within, AlN is quartz (SiO ₂₎
It is superior to corrosiveness compared to
The N material is hardly scraped.

Further, since the electrostatic chuck 72 for adsorbing and holding the wafer W uses the SiC thin film 78 which is superior in heat resistance to the conventionally used polyimide resin, the process temperature is 400.degree. Even if the temperature is raised to around 600 ° C., it will not be damaged by heat. Furthermore, in this way, instead of the polyimide resin, the SiC thin film 7
By using No. 8, the potential difference of the wafer W with respect to the plasma can be made large, and as a result, the deposition efficiency in the vertical direction can be increased, so that the occurrence of voids and the like during the filling of the interlayer insulating film can be significantly suppressed. be able to.

Here, the index θ for judging the quality of the buried shape of the interlayer insulating film will be described. Figure 17 shows Al
FIG. 17 (A) shows a state in which an interlayer insulating film (SiO ₂ ) is buried in the wiring surface, FIG. 17 (A) shows a state in which the buried shape is bad and a void is generated, and FIG. 17 (B) is a void generated. 17C shows a critical state, and FIG. 17C shows a state in which the embedded shape is good and voids do not occur.

In this case, as an index for judging the embedding state, the horizontal line passing through the corner of the Al wiring 136 and the wiring groove portion 1
The angle θ formed by the tangent line of the deposited SiO ₂ of 38 on the groove exit side is used. That is, when the angle θ is larger than 90 degrees, the void 140 tends to occur, whereas when the angle θ is smaller than 90 degrees, the void tends not to occur and the angle θ is preferably small. Now, as described above, when SiC is used as the insulating material of the electrostatic chuck 72, voids are not generated, or even if they are generated, they are very small, which is a good result.

FIG. 19 (A) is an SEM photograph showing a buried state when a SiC electrostatic chuck is used.
(B) is an SEM (scanning electron microscope) photograph showing an embedded state when a polyimide electrostatic chuck is used. As is clear from these photographs, in the case shown in FIG. 19 (A), the angle θ is about 100 degrees, and the voids are not generated or are very small even if they are generated, but in the case shown in FIG. 19 (B). The angle θ is about 125 degrees and a considerably large void is generated,
Not preferred.

Further, in this embodiment, plasma CV is used.
During the D film formation, since the bias voltage is applied from the bias voltage source 90 to the susceptor 64 at a high frequency voltage having a frequency within the range of 1 MHz to 10 MHz, the self-bias effect of the susceptor becomes large, and as a result, the vertical direction is increased. Since it is possible to further improve the deposition efficiency of, it is possible to further suppress the generation of voids. The bias voltage is preferably set to a frequency near 2 MHz. As described above, the reason why the frequency band of the bias voltage is limited is that the SiC material used for the electrostatic chuck has poor permeability of the electric field in the frequency band lower than 1 MHz, and the electric field in the frequency band higher than 10 MHz. Is because the ions are too heavy to follow the vibration.

Here, the frequency dependence of the bias voltage will be described based on an actual SEM photograph. FIG. 20 is an SEM photograph showing the embedded state when the frequency of the bias voltage is variously changed. 20A shows the case where the frequency of the bias voltage is 400 KHz (500 W).
(B) has a bias voltage frequency of 2 MHz (300 W)
20C, the frequency of the bias voltage is 13.
The case of 56 MHz (300 w) is shown. Also,
FIG. 18 is a graph summarizing the evaluation results of the above SEM photographs.

As is clear from this photograph, when the frequency of the bias voltage is 500 KHz which is smaller than 1 MHz (FIG. 20 (A)), the angle θ is about 100 degrees, a void is generated, and the frequency is less than 10 MHz. Also big 1
In the case of 3.56 MHz (FIG. 20 (C)), the angle θ is about 115 degrees, and the void is generated also in this case. On the other hand, when the frequency is 2 MHz (Fig. 20)
In (B), no void is generated and a good result is shown.

During the film formation, some reaction products flow in the vacuum exhaust system 96 together with the exhaust gas. A cold trap 98 is provided immediately before the vacuum pump 94 of this exhaust system. Therefore, the exhaust gas is in the baffle plate 102A ~
Meandering trap passage 108 partitioned by 102C
When passing through, the reaction products contained in the gas adhere to the baffle plate surface and are removed from the gas. In this case, in particular, since each baffle plate is cooled by flowing the cooling water through the refrigerant passage 110, the trap efficiency of the reaction product can be further improved. Therefore, the reaction products can be efficiently removed from the exhaust gas, and it is possible to eliminate the risk of damaging the vacuum pump on the downstream side. If a predetermined amount of reaction product adheres to each baffle plate, the trap box 10 is detachable.
Replace 0 with a new box.

Furthermore, since the inner wall of the processing container 62 is not subjected to a hard alumite treatment or the like and is made of a stripping material of aluminum, Mg which may cause metal contamination even if it is sputtered by plasma ions. It is possible to prevent a decrease in yield without releasing such substances.

In order to form an interlayer insulating film, TEOS, TMOS (tetramethylorthosilicate), OMCTS (octamethylcyclotetrasiloxane), TMCTS (tetramethyl) is used as a disilane or an organic silicon source instead of silane. Cyclotetrasiloxane) or the like, or ozone (O ₃ ) gas may be used instead of O ₂ gas to react this with an organic silicon source. The present invention can be applied when forming an interlayer insulating film other than a silicon oxide film or another thin film.

In each of the above-described embodiments, the plasma etching process or the plasma CVD process has been mainly described as an example. However, the present invention is not limited to this, and is applied to other processes such as a plasma sputtering process and a plasma ashing process. Of course, you can. Further, although the semiconductor wafer has been described as an example of the object to be processed, the present invention is not limited to this and can be applied to an LCD substrate or the like.

[0085]

As described above, according to the plasma processing apparatus of the present invention, the following excellent operational effects can be exhibited. According to the first aspect of the invention, the antenna member is housed in the processing container, and inductive coupling by the antenna member,
Since the plasma is generated by combining the capacitive coupling between the antenna member and the processing container or the susceptor, a vacuum higher than 1 × 10 ⁻³ Torr, which cannot generate plasma in the conventional parallel plate type electrode structure, is used. The object to be processed can be processed by generating plasma even under a high vacuum of 1 × 10 ⁻⁶ Torr, for example. Therefore, in such a vacuum atmosphere, it is possible to suppress the scattering of ions and the like, so that the anisotropy of the processing and the processing rate are improved without complicating the apparatus, and the etching pattern interval can be made finer. It is possible to improve the uniformity of the film thickness of the fine etching process or the film formation on the object to be processed. Further, by housing the antenna member in the processing container, the entire container can be formed of a conductive member such as aluminum, as compared with the case where the antenna member is provided outside the container, and electromagnetic wave sealing measures are taken and expensive thick wall is used. Since it is not necessary to use a transparent quartz plate or the like, it is possible to contribute not only to cost reduction but also to prevent leakage of harmful gas due to breakage of the quartz plate. Moreover, the distance between the antenna member and the susceptor is shortened, and the plasma generation efficiency can be improved. According to the second aspect of the present invention, in the inductively coupled plasma generation method, since the ceramic material having excellent heat resistance and durability is used for the ceiling portion, the plasma generation density can be maintained high and the process temperature is also set high. Therefore, for example, the deposition efficiency at the time of film formation can be increased, and the risk of damage can be reduced as compared with the case of using quartz or the like. Further, by using the AlN material as the ceramic material, it is possible to further improve durability, heat resistance and corrosion resistance. Moreover, since the influence of spatter is less likely to occur, the generation of particles is reduced, and the amount scraped during cleaning can be greatly suppressed. Furthermore, when an electrostatic chuck coated with a SiC material having excellent heat resistance is used, it is possible to perform processing at a high process temperature as described above as compared with a conventional chuck made of polyimide resin.
Further, the potential difference of the object to be processed with respect to the plasma can be increased to enhance the attraction of ions, and as a result, the vertical deposition efficiency at the time of film formation is improved, voids and the like are not generated, and the embedding efficiency can be improved. In addition, at the time of film formation, 1 MH
By applying a bias voltage having a frequency within the range of z to 10 MHz to the susceptor, the self-bias effect can be further enhanced, the potential difference on the susceptor side with respect to the plasma can be further enhanced, and the embedding efficiency can be further improved. Furthermore, by providing a cold trap in the vacuum exhaust system, it is possible to remove the reaction products contained in the exhaust gas during the plasma CVD process, and prevent the vacuum pump and the like from being adversely affected.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of a plasma processing apparatus according to the first invention.

FIG. 2 is a plan view showing an antenna member of the device shown in FIG.

FIG. 3 is a plan view showing a one-turn antenna member.

FIG. 4 is a sectional view showing a second embodiment of the plasma processing apparatus of the present invention.

FIG. 5 is a sectional view showing a third embodiment of the plasma processing apparatus of the present invention.

FIG. 6 is a diagram showing a change in a processing rate curve when an arrangement state of antenna members is changed.

FIG. 7 is a sectional view showing a fourth embodiment of the plasma processing apparatus of the present invention.

8 is an enlarged cross-sectional view of an antenna member of the processing device shown in FIG.

FIG. 9 is a sectional view showing a fifth embodiment of the plasma processing apparatus of the present invention.

FIG. 10 is a sectional view showing a sixth embodiment of the plasma processing apparatus of the present invention.

FIG. 11 is a sectional view showing a seventh embodiment of the plasma processing apparatus of the present invention.

FIG. 12 is a sectional view showing an eighth embodiment of the plasma processing apparatus of the present invention.

FIG. 13 is a sectional view showing a plasma processing apparatus (plasma CVD apparatus) according to a second invention.

FIG. 14 is a plan view showing an antenna member.

FIG. 15 is an exploded view showing an electrostatic chuck.

FIG. 16 is a cross-sectional view showing a cold trap.

FIG. 17 is a cross-sectional view showing various situations when an interlayer insulating film (SiO ₂ ) is embedded on the surface of an Al wiring.

FIG. 18 is a graph showing the frequency dependence of the bias voltage in the embedded state.

FIG. 19 is an SEM photograph showing an embedded state in a SiC electrostatic chuck and a polyimide electrostatic chuck.

FIG. 20 is an SEM photograph showing the frequency dependence of the bias voltage in the embedded state.

[Explanation of Codes] 4 Processing Container 6 Antenna Member 8, 8A, 8B High Frequency Power Supply for Plasma Generation 20 Susceptor 26 Ceramic Heater 30 Cooling Jacket 32 Antenna Part 38 Antenna Protective Cover 42 Cylindrical Coil Part 46 Protective Layer 52 Showerhead 60 Plasma CVD apparatus (plasma processing apparatus) 62 Processing container 64 Susceptor 72 Electrostatic chuck 76 Conductive thin film 78 SiC thin film 90 Bias voltage source 96 Vacuum exhaust system 98 Cold trap 102A, 102B, 102C Baffle plate 110 Refrigerant passage 122 Ceiling 126 Antenna Member 128 High frequency power supply 130 High frequency power supply system W Semiconductor wafer (processing target)

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical indication location H05H 1/46 L 9216-2G (72) Inventor Jiro Hata 2-3-1, Nishi-Shinjuku, Shinjuku-ku, Tokyo Tokyo Within Electron Co., Ltd. (72) Kenji Ishikawa 1-241, Machiya, Shiroyama-cho, Tsukui-gun, Kanagawa Prefecture Tokyo Electron Tohoku Co., Ltd. Sagami Business Office

Claims (11)

[Claims] 1. A plasma processing apparatus for performing plasma processing on an object to be processed placed on a susceptor in an airtight processing container, wherein an antenna member is provided in the processing container at a position facing the susceptor. A plasma processing apparatus, wherein the plasma processing apparatus is arranged, and a high-frequency power source for plasma generation is connected to the antenna member. 2. The plasma processing according to claim 1, wherein the antenna member is composed of a planar antenna part wound one or more times in a plane parallel to the plane of the object to be processed. apparatus. 3. The plasma processing apparatus according to claim 1, wherein the antenna member includes a cylindrical coil portion that is spirally wound in a direction orthogonal to the plane of the object to be processed. 4. The antenna member includes a planar coil portion wound one or more times in a plane parallel to the plane of the object to be processed, and a spiral in a direction orthogonal to the plane of the object to be processed. The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus comprises a cylindrical coil portion wound in a circular shape. 5. A plasma processing apparatus for performing plasma processing on an object to be processed placed on a susceptor in an airtight processing container, wherein a ceiling portion of the processing container is formed of a dielectric that transmits radio waves. In addition, at least the inner surface side of the ceiling portion is formed of a ceramic material, an antenna member is arranged on the upper surface side of the ceiling portion so as to face the susceptor, and a high frequency power source for plasma generation is connected to the antenna member. A plasma processing apparatus having the above configuration. 6. The plasma processing apparatus according to claim 5, wherein the ceramic material is made of AlN. 7. The plasma processing apparatus according to claim 5, wherein the dielectric is made of quartz or AlN. 8. A plasma processing apparatus for performing a plasma process on an object to be processed placed on a susceptor in an airtight processing container, wherein an antenna member is arranged at a position facing the susceptor, and the antenna member is provided. A plasma processing apparatus, characterized in that a high-frequency power source for plasma generation is connected to, and an electrostatic chuck formed by coating a conductive thin film with a SiC thin film is provided on the upper surface of the susceptor. 9. The susceptor includes 1 MHz to 10 M
9. The plasma processing apparatus according to claim 8, wherein a bias voltage source for applying a high frequency bias voltage within a range up to Hz is connected. 10. The plasma processing apparatus according to claim 8, wherein the bias voltage is approximately 2 MHz. 11. A plasma processing apparatus for performing a plasma process on an object to be processed placed on a susceptor in an airtight processing container, wherein an antenna member is arranged at a position facing the susceptor, and the antenna member is provided. A plasma processing apparatus, characterized in that a high frequency power source for plasma generation is connected to, and a cold trap for removing reaction products is provided in a vacuum exhaust system of the processing container.