JPH10284299A - High frequency introducing member and plasma device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high frequency introducing member which functions also as a counter electrode to high frequency bias and can contribute to enhancing the degree of freedom in the design of a plasma device. SOLUTION: A high frequency introducing member 16, provided as a part of a decompression container 12 so that a high frequency electromagnetic field released from an antenna 28 placed outside the decompression container 12 is introduced into the decompression container 12, has a high frequency introducing member main body 18 made from a dielectric material and a conductive thin film 22 such as a thin film of titanium provided on one side of the high frequency introducing member main body 18. Because such a conductive thin film 22 is provided, the high frequency introducing member 16 functions also as an electrode and can have a large electrode area ratio. As a result, when it is applied to a dry etching device 10, etching speed, selection ratio, and the like can be enhanced, and sputtering on the inside surface of the container is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inductively coupled plasma apparatus used for plasma processing and microanalysis used in a process of manufacturing a macroelectronic device such as a semiconductor integrated circuit device and a liquid crystal display device. The present invention relates to a high-frequency introducing member which is a main component of a simple inductively coupled plasma device.

[0002]

2. Description of the Related Art In order to improve the performance of macroelectronic devices such as semiconductor integrated circuit elements and liquid crystal display elements and to reduce costs, high-precision and high-speed microfabrication (dry etching, etc.) that can withstand large-scale integration is required. There is an increasing demand for realizing an area on a substrate to be processed. Processing using plasma is suitable for such fine processing, and an inductive coupling method (Inductiv method) is used as a technique for forming such plasma.
ely coupled system).

In the inductive coupling method, generally, a high frequency is applied to an antenna disposed outside the decompression vessel, and an electromagnetic field induced inside the decompression vessel through a high-frequency introducing member provided in the decompression vessel causes electrons in the plasma to be generated. To maintain the plasma. This method is characterized in that high-density plasma can be maintained in a relatively high vacuum (about 10 ⁻³ Torr). For this reason, the directionality of ions incident on the substrate to be processed is well aligned, and when used for dry etching, for example, the perpendicularity between the substrate surface and the processing surface is high, and high-frequency processing can be realized. Further, since a large amount of ions can be drawn into the substrate to be processed from the plasma, it is suitable for high-speed processing.

Further, when applying inductively coupled plasma to dry etching technology, it is necessary to apply a high frequency bias for drawing ions into the substrate to be processed, separately from the high frequency for forming the plasma. The high frequency bias current flows from the substrate to be processed through the cathode sheath into the plasma, and from the plasma through the anode sheath into the wall of the vacuum vessel. At this time, the area of the decompression container serving as the anode is determined with respect to the area of the susceptor electrode serving as the cathode.
When sufficiently large (3 to 5 times), the potential difference between the plasma and the depressurized vessel becomes smaller, while the potential difference between the plasma and the cathode becomes relatively larger. Therefore, the ion energy on the substrate to be processed becomes relatively large, and high etching efficiency can be obtained. On the other hand, since the voltage on the anode sheath side is relatively small, adverse effects such as exhaustion of the decompression container due to ion sputtering and contamination by the product are suppressed.

[0005]

By the way, since the induced electromagnetic field cannot pass through the inside of the conductor, conventionally,
Dielectrics (insulators) such as fused quartz and ceramics have been used as high-frequency introduction members for inductively coupled plasma devices. Since no high-frequency bias current flows in this portion, it is not included in the area of the anode. Therefore, as the area of the high frequency introducing member is increased, it is more difficult to secure the area ratio of the anode (the conductive portion of the inner wall of the depressurized container grounded to the ground) to the cathode (the electrode on which the substrate to be processed is mounted). Become.

[0006] In particular, when processing a substrate to be processed having a large area,
Conventionally, a hemispherical high-frequency introducing member 116 is disposed at a position facing the substrate 34 to be processed, as shown in FIG. However, since the high-frequency introducing member 116 is made of only a dielectric material, only the metal decompression vessel wall 14 having a small area on the side becomes the anode. In this case, since the area of the anode is almost the same as the area of the cathode, the potential difference between the plasma and the cathode is too small to decrease the etching rate, or conversely, the potential difference between the plasma and the anode increases. There is a problem that ion sputtering becomes intense, and that the decompression container 12 is consumed and metal contamination on the substrate 34 to be processed increases.

On the other hand, if the height and radius of the depressurized container 12 are increased in order to increase the area ratio, the volume of the depressurized container 12 increases. In this case, there is a problem that the cost and the installation area of the apparatus are increased, such as a need for a pump having a large exhaust capacity and an increase in the size of a transport mechanism for the substrate 34 to be processed.

The present invention has been made in view of the above circumstances, and a main object of the present invention is to provide a high-frequency introducing member which also functions as a counter electrode to a high-frequency bias and can contribute to an increase in the degree of freedom in designing a plasma device. It is in.

Another object of the present invention is to provide an inductively-coupled plasma apparatus which is capable of using the high-frequency introducing member and having high performance and capable of coping with a large-diameter substrate to be processed.

[0010]

In order to achieve the above object, an object of the present invention is to introduce a high-frequency electromagnetic field emitted from an antenna disposed outside a pressure reducing container into the pressure reducing container. The high-frequency introducing member provided as a part of the decompression container has a high-frequency introducing member main body made of a dielectric material and a conductive thin film provided on one surface of the high-frequency introducing member main body.

[0011] Here, it functions as a support that maintains the airtightness inside and outside the decompression vessel and withstands a pressure difference between inside and outside. In addition, a conductive thin film such as a metal thin film can be used as an electrode for passing a high-frequency bias applied to a substrate to be processed.

The conductive thin film can transmit most of the electromagnetic waves emitted from the antenna by setting it to an appropriate thickness or less. In this case, a measure of the thickness of the conductive thin film is given in relation to the frequency applied to the antenna. That is, if the thickness of the conductive thin film exceeds the skin depth at high frequency, the thin film blocks high frequency as much as a thicker metal. It is desirable that the thickness of the conductive thin film be sufficiently smaller than this skin depth.

Further, even if the conductive thin film has a thickness greater than the skin depth, it is composed of a plurality of portions that are divided from each other and arranged along the transmitting surface, so that most of the electromagnetic waves emitted from the antenna can be transmitted. I can do it. With such a configuration, it acts as a dielectric against electromagnetic waves from the antenna, and exhibits a conductive property against high frequency bias. Therefore, even if this high-frequency introducing member is used for most of the vacuum container, the area of the anode does not decrease.

The present invention also extends to a plasma apparatus such as a dry etching apparatus or a CVD apparatus using the high-frequency introducing member as described above. Since such a high-frequency introducing member has the above-described effects, the plasma device to which the high-frequency introducing member is applied can solve the above-described problems.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

FIG. 1 shows a dry etching apparatus 10 using inductively coupled plasma according to a first embodiment of the present invention. The dry etching apparatus 10 includes a reaction vessel (decompression vessel) 12 whose inside is decompressed. The reaction vessel 12 is composed of a vessel wall 14 made of a metal material such as stainless steel, and a hemispherical dome-shaped high-frequency introducing member, a so-called window 16, attached to an upper portion thereof.

As shown in FIG. 2, the structure of the window 16 has a window body 18 made of alumina, and the entire inner surface of the window body 18 is arranged in order toward the inside of the reaction vessel 12. 100 angstrom thick titanium nitride thin film 2
0 and 200 angstrom thick titanium thin films 22 and 1
The titanium nitride thin film 24 having a thickness of 00 Å is formed by an appropriate method such as a sputtering method. The inner surface of the titanium nitride thin film 24 has a thickness of 3 by plasma spraying.
A 00 micron alumina film 26 is coated. The titanium thin film 22 is conductive and is grounded together with the container wall 14. The titanium nitride thin films 20 and 24 above and below the titanium thin film 22 serve as barrier layers for preventing the titanium thin film 22 from reacting with oxygen atoms in the alumina ceramic and being deteriorated. In addition, such thin films 20 and 2
The window (high-frequency introducing member) 16 according to the present invention in which the layers 2 and 24 are laminated is hereinafter referred to as a laminated window 16.

A high-frequency antenna 28 for inducing high-frequency waves in the reaction vessel 12 and supplying energy for maintaining plasma is wound in a spiral coil shape outside the laminated window 16. A high frequency power supply 32 of 13.56 MHz, for example, is connected to both ends of the antenna 29 via an impedance matching unit 30.

A susceptor 36 on which a silicon wafer 34 as a substrate to be processed is placed is disposed inside the reaction vessel 12. On the upper surface of the susceptor 36, an electrostatic chuck 38 for fixing the silicon wafer 34 is provided. The susceptor 38 also functions as an electrode and is grounded via a high frequency bias power supply 40. Accordingly, a high-frequency bias voltage of, for example, 13.56 MHz is applied to the grounded container wall 14 and the titanium thin film 22 of the laminated window 16, and the susceptor 36 functions as a cathode to function as a container.
And the titanium thin film 22 functions as an anode.

The reaction vessel 12 is provided with a gas supply port for introducing an etching gas supplied from a gas supply source (not shown) into the inside, and further for exhausting the inside. An exhaust port 44 connected to a vacuum pump (not shown) is provided.

Next, such a dry etching apparatus 1
The operation and effect of 0 will be described in comparison with the dry etching apparatus 100 having the conventional configuration shown in FIG. It is assumed that the conventional device has the same configuration as the device shown in FIG. 1 except that the window 116 is made of only alumina and does not have a laminated structure. Further, in the dry etching apparatus 10 shown in FIG. 1, the area ratio of the upper surface of the susceptor 36 (the portion functioning as an electrode) to the container wall 14 and the titanium thin film 22 was 2.0 and 4.5, respectively.

Table 1 shows the self-bias voltage Vdc (V) and the bias power density generated on the silicon wafer 34 when plasma is formed by the high frequency antenna 28 to dry-etch the silicon oxide film on the silicon wafer 34. W / cm ² ). In this case, a mixed gas of CHF ₃ and Ar (CHF ₃ : A), which is a typical etching gas for a silicon oxide film, is placed in the reaction vessel 12.
r = 1: 5) to 200 sccm (cc ³ .atm / mi)
The internal pressure was maintained at 10 mTorr while introducing the gas from the gas supply port 42 at the flow rate n), and a high-frequency power of 3 kW was applied to the antenna 28 to form plasma in the reaction vessel 12.

[0023]

[Table 1]

Here, the self-bias voltage means the susceptor (electrode) 3 capacitively via the insulator of the electrostatic chuck 38.
6 refers to a temporal average value of a bias voltage generated on the silicon wafer 34 connected to 6. As in this example,
If ion scattering can be almost neglected at relatively low pressure,
The self-bias voltage is applied to the silicon wafer 34 from the plasma.
Approximately corresponds to the average energy of the ions accelerated toward.

In etching a silicon oxide film,
In order to induce an etching reaction, bombardment of ions having relatively large kinetic energy is required.
Needs to be obtained. Accordingly, Table 1 shows that the conventional dry etching apparatus 100 using the window 116 made of only a dielectric requires a bias power density of about 3 W / cm ² . Since the processing electrode, that is, the upper surface of the susceptor 36 needs to be designed to be larger than the area of the wafer 34, when processing a 200 mm diameter silicon wafer 34, the area of the susceptor upper surface is 300c.
m ^{2 to} 400 cm ² . Therefore, when the area of the upper surface of the susceptor is 400 cm ² , the susceptor 36 serving as the cathode
1.2 kW as a whole between the container wall 14 as an anode
Table 1 shows that it is necessary to input the bias power of

When such a large amount of bias power is applied, the temperature of the silicon wafer 34 rises abnormally, and the etching rate of the photoresist film serving as an etching mask increases, and the etching ratio decreases. There are adverse effects on the characteristics. Furthermore, since the bias power of 30% to 40% of the energy input to the antenna 28 heats the plasma, there is a possibility that the uniformity is deteriorated and the electron temperature is increased.

On the other hand, according to the dry etching apparatus 10 having the laminated window 16 according to the present invention, 1.0 W / cm ²
A self-bias voltage of 600 V can be generated with the following bias power density. Therefore, the power applied to the entire susceptor 36 is also suppressed to 400 W or less, and can be suppressed to 13% of the power supplied to the high-frequency antenna 28.

Table 2 shows the results of comparison of the etching characteristics between the dry etching apparatus 10 according to the present invention and the conventional apparatus 100. When a bias power as large as 1200 W is applied to the susceptor 36 in the conventional dry etching apparatus 100, the etching rate is relatively large at 1050 nm / min, but the selectivity for photoresist and silicon is only 6.2 and 18, respectively. Absent. On the other hand, the susceptor 3 is
When a small bias power of about 400 W was applied to No. 6, it was confirmed that the etching rate was slightly lowered, but the selectivity was improved by a factor of 2 to 3.

[0029]

[Table 2]

The high frequency applied from the outside by the antenna 28 is shielded from the inner surface of the window 116 by plasma in a space of about 20 mm. For this reason, the region where the high frequency is consumed and plasma is generated
It is limited to the area of about 20 mm to 20 mm. The average kinetic energy of the electrons in this part is relatively large, and is about 4 to 8 eV in terms of the electron temperature. However, there is a distance of about 100 mm from this portion to the silicon wafer 34. Since the mean free path of the electrons heated by the electromagnetic field in the plasma forming region is several mm, the electrons are diffused into the afterglow region near the silicon wafer 34 while repeating a random walking motion of a distance of several mm each time. During this time, electrons diffuse while losing energy due to impact with gas molecules,
The low electron temperature plasma reaches the silicon wafer 34.

Since high-energy electrons in the plasma having a high electron temperature have a large random component of directivity when entering the silicon wafer 34, ions having relatively uniform directivity when entering into a narrow groove or hole. Causes an imbalance, and causes charging at the bottom or side wall of the groove or hole. This charging causes the aspect ratio dependence of the etching rate and the charge-up damage. In response to these phenomena, it is extremely effective to arrange the silicon wafer 34 in the afterglow region and suppress the electron temperature of the plasma at the time when the silicon wafer 34 acts on the silicon wafer 34. However, in the conventional dry etching apparatus 100, since a relatively large bias power needs to be applied, the temperature of electrons tends to increase again in the vicinity of the silicon wafer 34.

On the other hand, when the dry etching apparatus 10 provided with the laminated window 16 of the present invention is used, the bias power required for the etching is relatively small, so that reheating hardly occurs. Table 3 shows the measured values.

[0033]

[Table 3]

It can be seen from Table 3 that the dry etching apparatus 10 of the present embodiment achieves a lower electron temperature even when no bias power is applied to the susceptor. 2 to 10k at both ends of the external high-frequency antenna 28
Although a relatively high voltage of W is generated, the electric field generated by the antenna 28 reaches the inside of the reaction vessel 12 in the conventional window 116 made of only a dielectric. For this reason, a local high electric field is generated in the plasma sheath near the end of the antenna 28. This electric field increases the electron temperature. On the other hand, when the laminated window 16 is used, the electric field does not enter the inside of the reaction vessel 12 due to the shielding effect of the titanium thin film 22. Therefore, the electron temperature of the dry etching apparatus 10 of the present embodiment is lower. Furthermore, the electron temperature at the time of bias application is 4.0 eV in the conventional device 100, and 2.0 eV in the device 10 of the present invention, which is suppressed to １ ／.

Table 3 also shows the frequency of electrostatic breakdown for MOS devices. The element used for this evaluation was Poly-S
A resist pattern with an aspect ratio of 5 is formed on an i-electrode type MOS capacitor, and has a structure sensitive to the influence of the incident angle distribution of electrons and ions. The breakdown voltage of the MOS insulating film after the plasma treatment was measured, and those having a voltage of 8 MV / cm or less were determined to be defective. In the case of using the laminated window 16 according to the present invention, no defect occurs regardless of the presence or absence of the bias. However, in the case of the conventional window 116 made of only the dielectric, about 20% of the defect is caused by the application of the bias power. It was confirmed that this would occur.

Table 3 shows the results obtained by processing and opening the contact holes and determining the percentage of defective conductivity. In this test, after a silicon oxide film having a thickness of 2.1 mm was deposited on the silicon wafer 34, a resist pattern having a line width of 0.40 mm was baked, and after etching, a metal wiring layer was buried to check for conduction. One test pattern includes about 10,000 contact holes, and has a chain structure connected in series with each other. Therefore, it is determined to be good only when all the holes in the test pattern are open. When the laminated window 16 was used, the defect rate was as small as 3.1%. The defect is at a level that can be considered to be mainly due to particles attached to the silicon wafer 34. On the other hand, when the window 116 made of only a dielectric material was used, an opening defect was observed in all test patterns.

When the electron temperature is high, the distribution of the incident angle is widened, and the electrons cannot reach the bottom of the contact hole having a large aspect ratio. As a result, the positive charges of the ions cannot be canceled, and as a result, an electric field that pushes the ions back near the bottom of the hole is generated, thereby inhibiting the etching. The opening defect is a result of stopping the etching of the bottom of the hole due to such a cause.

From the above results, when the electron temperature is suppressed as in the case where the silicon wafer 34 is placed in a portion away from the plasma formation region, that is, in the downflow region, particularly, the electron beam accompanying the bias application by using the laminated window 16 is used. It is clear that the effect of suppressing the temperature rise again can be obtained.
It has also been found that the etching characteristics are also improved accordingly. Further, the effect was confirmed by changing the pressure. As a result, when the following relationship exists between the distance (L) between the plasma formation region and the silicon wafer and the mean free path (l) of electrons at the pressure, In addition, it was also confirmed that this effect was remarkably exhibited.

L> 10 × l Therefore, the present invention is more effective in the configuration in which the silicon wafer 34 is arranged in the downflow region of plasma, and the distance between the silicon wafer 34 and the plasma formation region is reduced. In the case of 10 times or more of the mean free path, the effect is particularly remarkable.

On the other hand, there is known an amplitude modulation of a high frequency applied to the antenna 28, and an intermittent technique as an extreme example thereof. The purpose of these techniques is to form a plasma having a low electron temperature as in the case where the wafer 34 is placed in the downflow region. High frequency from 10 ms to 100
By intermittently or modulating at an interval of m seconds, the electron temperature can be efficiently reduced. Also in this case, the present technology having the effect of suppressing the reheating of electrons due to the bias high frequency is effective.

Further, by using the laminated window 16 of the present invention, the consumption of the material of the laminated window 16 and the container wall 14 is suppressed. That is, the energy of the ions colliding with the laminated window 16 and the inner surface of the container wall 14 is greatly reduced. The reason is as follows.
Depends on the point.

As described above, a high voltage of several kV or more is generated at both ends of the high-frequency antenna 28. If a conventional dielectric-only window 116 is used, the antenna 2
A high electric field of several tens of kV / cm is generated in the sheath between the inner surface of the window 116 near the end of FIG. 8 and the plasma, and accelerates ions in the plasma toward the window 116 of the portion. Even with a chemically stable material such as alumina, physical sputtering by energetic ions cannot be avoided.
On the other hand, when the laminated window 16 is used, the high electric field at the end of the antenna is shielded by the titanium thin film 22 and does not enter the plasma. Therefore, a potential difference generated between the inner surface of the laminated window 16 and the plasma is substantially equal to the plasma potential (Vp), and sputtering by ions is suppressed.

The second reason is that when the laminated window 16 is used, both the container wall 14 and the titanium thin film 22 of the laminated window 16 act as a ground electrode fixed to the ground with respect to the bias high frequency. The area of the earth electrode with respect to the plasma is increased, and the plasma potential (Vp) is suppressed both in a direct current and in an alternating current (and also in a fluctuation component).
Therefore, the energy of the ions is extremely small.

The dry etching apparatus 10 according to the present embodiment is also effective for suppressing metal contaminants on the silicon wafer 34. The characteristics of Si-MOS devices are significantly impaired by alkali metal and heavy metal contaminants adhering to the surface. For this reason, the amount of contamination adhering to the surface in the etching process must be suppressed to about 1 × 10 ¹⁰ atoms / cm ² . On the other hand, the materials of the window main body and the container wall contain a large amount of these metal elements which are the polluting sources. As these materials are depleted, a contaminant metal element will drift into the plasma, a significant portion of which will adhere to the wafer 34. However, when the laminated window 16 of the present invention is used, contamination by heavy metals such as Fe and Cr and light metals such as Na is suppressed to about 1/10 in both cases.

In setting the thickness of the titanium thin film 22 of the laminated window 16, the optimum film thickness is determined by the transmittance of the induction electromagnetic field to be transmitted and the impedance to the bias high frequency applied by the plasma device to be used for the window 16. Is selected. That is, first, the transmittance of the high-frequency electromagnetic field from the external high-frequency antenna 28 is large enough to be practically acceptable, and second, the in-plane potential distribution of the titanium thin film 22 connected to a fixed potential such as the antenna potential. However, the condition for selecting the thickness is that the resistance is small enough not to cause a practically problematic effect on the plasma. In the following discussion, since the titanium nitride thin films 20 and 24 are extremely thin and do not affect the transmittance of the high-frequency electromagnetic field, the titanium nitride thin films 20 and 24 are treated as if they do not exist.

One of the guidelines for giving the transmittance of the high-frequency electromagnetic field is the skin depth of the metal, which is given by the frequency of the induced electromagnetic field to be transmitted, and the resistivity and the magnetic permeability of the metal thin film. The skin depth (d) is represented by the following equation.

D = (2 / ωμσ) ^1/2 where ω, μ and σ are the high frequency angular frequency, the magnetic permeability and the conductivity of the metal thin film, respectively.

In general, electromagnetic waves cannot enter a sufficiently thick conductor. In particular, when the thickness of the metal thin film exceeds the skin depth, the electromagnetic wave is shielded almost equally to a thicker film and cannot be transmitted. Therefore, the skin depth is an index indicating the upper limit thickness of the titanium thin film 22 in the laminated window 16. In order to obtain a transmittance with negligible loss (1 to 10%), the thickness is desirably not more than about 1/1000 to 1/100 of the skin depth.

In the case of titanium, the skin depth is, for example, 13.5.
It has a value of about 30 microns for a high frequency of 6 MHz. On the other hand, the potential distribution in the plane of the thin film depends on the current value of the high-frequency bias, the shape of the laminated window 16, the connection method to the ground, and the like. As a rough guide, the surface resistance is 100
If it is kW or less, the effect is exhibited. In the case of titanium, this condition is satisfied if the thickness is 4 Å or more. Therefore, in the case of titanium, a thin film having a thickness of about 4 to 3000 angstroms satisfies these conditions. However, since the resistivity in such a thin film state may be larger than the bulk resistance value depending on the film forming means, it can be appropriately selected and used in the range of about 10 to 3000 Å.

On the other hand, the innermost alumina film 26 is made of a titanium thin film 22 made of a halogen-containing gas such as fluorine or chlorine contained in an etching gas, or an active species having high corrosion and etching properties such as an oxidizing gas such as oxygen or nitrogen dioxide. It is provided to protect. The alumina film 26 hardly chemically reacts with these active species and is suitable as a material for the protective film.

On the other hand, since the alumina film 26 is a dielectric, it functions as a capacitance resistor sandwiched between the titanium thin film 22 and the plasma. Therefore, when the thickness of the alumina film 26 is unnecessarily large, the resistance to the high frequency bias is large, and the effect of inserting the titanium thin film 22 may be offset.

However, the effect is not lost if the capacity of the alumina film 26 is equal to or larger than the capacity of the plasma sheath formed between the plasma and the laminated window 16. 1 × 10 ⁹ / c used in normal etching
In the case of low-temperature plasma having a density of about m ³ to 1 × 10 ¹¹ / cm ³ , the thickness of the plasma sheath is about 1 mm to 0.1 mm. Therefore, the thickness T of the alumina film 26 is equal to the thickness T
Divided by the dielectric constant ε is preferably set to be smaller than these values. Table 4 shows this relationship.

[0053]

[Table 4]

The protective film is not limited to the alumina film 26. Under the same plasma conditions, the thickness of the internal protective film can be set large by using a material having a larger dielectric constant. In particular, when the thickness exceeds 1 mm, ceramic formed by sintering can be used as a protective film. Further, when the thickness exceeds 10 mm, the pressure difference between the inside and outside of the reaction vessel can be maintained only at this portion. In such a case, a high dielectric ceramic film such as titania may be used as a protective film, and a titanium thin film may be formed on the outer surface, that is, on the window body side.

FIG. 3 is a schematic view showing another embodiment of the dry etching apparatus constituted according to the present invention. In this embodiment, the laminated window 216 is not hemispherical but has a truncated cone shape, and the antenna 28
It is substantially the same as the device 10 shown in FIG. 1 except that is wound.

In the laminated window 216, the window main body 21
As a dielectric material of the protective film 8 and the protective film 226, an alumina sintered body to which a small amount of titanium is added is used. By adding titanium to the main component alumina, the dielectric constant can be increased.

When manufacturing the laminated window 216, first, a protective film 226 having a thickness of 3 mm is formed from an alumina sintered body having a dielectric constant of 50. Next, a multilayer film 250 of a titanium nitride thin film, a titanium thin film and a titanium nitride thin film is sequentially formed on the conical outer peripheral surface of the protective film 226. And
Further, an alumina sintered body 218 having a thickness of 10 mm is joined to the outer surface to form a laminated window 216 shown in FIG.

In the case of the illustrated embodiment, the top portion of the laminated window 216 is made of only an alumina sintered body,
By providing a gap at the top of 18, a tolerance caused during processing is absorbed by vertical displacement, and air and gas remaining in the gap at the time of joining are released to form bubbles and to form a bonded part. Prevents peeling.

This manufacturing method is characterized in that the inner surface in contact with the plasma can be formed of a sintered body whose composition can be easily controlled and processed.
Particularly suitable for forming a flat laminated window.

FIG. 4 shows a third embodiment of the laminated window according to the present invention. The laminated window 316 uses a titania sintered body as a dielectric material. In manufacturing the window 316, first, a titania sintered body 326 having a dielectric constant of 80 and a thickness of 15 mm is formed on the side exposed to the plasma. This functions as a protective film, but also functions as a window main body that supports a metal thin film such as a titanium thin film. Next, the titanium nitride thin film 324, the titanium thin film 322, and the titanium nitride thin film 320 are formed on the outer surface of the titania sintered body 326.
To form a film. On these outer surfaces, a silicate glass coating layer 350 for protecting from moisture and oxygen in the air is formed.

This structure is characterized in that the inner surface in contact with the plasma can be formed of a sintered body whose composition and purity can be easily controlled, and that since it is relatively simple, it can be formed into various structures. In addition, this structure is particularly suitable for a surface treatment that does not require a large power supply to form a high-density plasma because a usable plasma density region is limited.

FIG. 5 shows a fourth embodiment of the laminated window 416 of the present invention. The laminated window 416 has a cylindrical shape, and the antenna 28 is arranged so as to surround the cylindrical laminated window 416. The configuration itself of the laminated window 416 is substantially the same as that shown in FIG. 1, and as shown in FIG. 6, a window main body 418 made of cylindrical alumina, a titanium nitride thin film 420 disposed on the inner surface thereof, Titanium thin film 4
Film 450 composed of titanium oxide film 22 and titanium nitride thin film 424
And a protective film 42 made of alumina disposed inside the
6 is comprised. Here, the multilayer film 450 does not extend continuously over the entire circumference but is divided at regular intervals. For example, each of the multilayer films 450 has a rectangular shape having a long side of 50 mm and a short side of 10 mm, and is spaced apart from each other by 0.5 mm so that the long side direction is substantially orthogonal to the current direction of the antenna 28. They should be arranged.

Using such a divided configuration, 30
Even if a relatively thick titanium thin film 422 of about μm is used, it is possible to suppress a decrease in high-frequency transmittance. Also,
The reduction in the electrode area is also about 5%, and a sufficient effect can be obtained for the bias current.

Another multilayer film 470 composed of a titanium nitride thin film 460, a titanium thin film 462, and a titanium nitride thin film 464 is attached to the lower end surface of the laminated window 416. Are arranged in such a way that they overlap each other. Further, a thin silicate glass film 480 is applied so as to cover the multilayer film 470. The multilayer 470 forms a capacitor with the multilayer 450 and allows it to be capacitively connected to the reaction vessel wall.

FIGS. 7 and 8 show still another embodiment. In the laminated window 516 according to this embodiment, a window body 51 made of ceramic such as alumina or titania on a flat disk is used.
8, a titanium thin film 520 is deposited on one side by a sputtering method, and then a 50 μm thick gold thin film 52 is screen-printed.
2 are formed. The gold thin film 522 radially extends from the center of the circular window main body 518 toward the peripheral portion, and forms a linear pattern having a width of about 1 mm.
Further, the gold thin film 522 is coated with a coating type silicate glass layer 526.
It is covered with. The antenna 28 is arranged on the side opposite to the side on which these patterns are formed, and has a spiral structure.

Although the preferred embodiment of the present invention has been described above, it is needless to say that the present invention is not limited to the above embodiment.

For example, in the above embodiment, the case where the present invention is mainly applied to a dry etching apparatus has been described. However, the same effect can be expected when the present invention is applied to another process apparatus such as a plasma CVD apparatus. . Especially,
Suppression of the consumption of the reaction vessel and suppression of contaminants generated due to this are common issues in all microelectronics manufacturing technologies such as semiconductors and liquid crystal display elements. Inductively coupled plasma is also used for ultra-trace chemical analysis such as mass spectrometry and emission spectrometry. If the high-frequency conductive member of the present invention is used in these devices, the amount of interfering elements released from the reaction vessel is reduced, so that the minimum detection purity can be improved.

Further, in the above embodiment, titanium and gold are listed as materials of the metal thin film used for the high-frequency introducing member (laminated window), but other metal materials or conductive materials can be used as appropriate. . In addition, other dielectric materials can be used.

[0069]

According to the present invention as described above,
For high frequency electromagnetic fields, it shows properties similar to dielectrics,
It is possible to provide a high-frequency introducing member having both advantages of acting like a conductor with respect to a high-frequency bias voltage.

Further, by using the high-frequency introducing member according to the present invention, in a surface treatment step such as dry etching or a CVD apparatus, high-performance and suppressing an adverse effect on an element such as electrostatic damage and contamination, and furthermore, It is possible to provide a plasma device with less wear of the member.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a dry etching apparatus according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view schematically showing a portion A in FIG.

FIG. 3 is a schematic sectional view showing a dry etching apparatus according to a second embodiment of the present invention.

FIG. 4 is an enlarged sectional view schematically showing another embodiment of the high frequency introducing member (laminated window) according to the present invention.

FIG. 5 is a perspective view schematically showing still another embodiment of the high frequency introducing member (laminated window) according to the present invention.

FIG. 6 is a sectional view taken along line BB of FIG. 5;

FIG. 7 is a plan view schematically showing another embodiment of the high frequency introducing member (laminated window) according to the present invention.

FIG. 8 is a sectional view taken along the line CC of FIG. 7;

FIG. 9 is a sectional view schematically showing a conventional dry etching apparatus.

[Explanation of symbols]

10 ... Dry etching device (plasma device), 12 ...
Reaction vessel (reduced pressure vessel), 14: vessel wall, 16: laminated window (high frequency introduction member), 18: window body (high frequency introduction member body), 20: titanium nitride thin film, 22: titanium thin film (conductive thin film), 24 ... titanium thin film, 26 ... alumina film (protective film), 28 ... antenna, 32 ... high frequency power supply, 34 ... silicon wafer (substrate to be processed), 36 ... susceptor (electrode),
40 ... High frequency bias power supply.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Haruo Okano 14-3 Shinsen, Narita-shi, Chiba Pref. Nogedaira Industrial Park Applied Materials Japan Co., Ltd.

Claims (15)

[Claims] 1. A high-frequency introducing member provided as a part of a pressure-reducing container for introducing a high-frequency electromagnetic field emitted from an antenna disposed outside a pressure-reducing container into the pressure-reducing container. A high-frequency introducing member body,
And a conductive thin film provided on one surface of the high-frequency introducing member main body. 2. The high-frequency introducing member according to claim 1, wherein the conductive thin film has a thickness that allows the high-frequency electromagnetic wave to pass therethrough. 3. The apparatus according to claim 1, wherein the conductive thin film includes a plurality of portions arranged along a transmission surface at a predetermined interval from each other so as to transmit the high-frequency electromagnetic wave. The high-frequency introduction member according to any one of the preceding claims. 4. The high-frequency introducing member according to claim 1, wherein the conductive thin film is formed on a surface of the high-frequency introducing member body facing the inside of the decompression container. 5. The high frequency introducing member according to claim 4, wherein a protective film made of a dielectric material is coated on the conductive thin film. 6. The high frequency introducing member according to claim 1, wherein a ceramic sintered material or a glass material having a relative dielectric constant of 10 or more is used as said dielectric material. 7. The high-frequency introducing member according to claim 1, wherein the conductive thin film is made of a metal material. 8. A depressurized container accommodating a substrate to be processed, a unit for introducing a processing gas into the depressurized container, an exhaust unit for maintaining the depressurized container at a reduced pressure, An antenna that is applied to emit a high-frequency electromagnetic field, wherein the high-frequency electromagnetic field emitted from the antenna is introduced into the decompression container to form a plasma, and the plasma device is formed as a part of the decompression container. A plasma apparatus, wherein the high-frequency introducing member provided includes a high-frequency introducing member main body made of a dielectric material, and a conductive thin film provided on one surface of the high-frequency introducing member main body. 9. The conductive thin film is disposed on an inner surface of the high-frequency introducing member main body and is electrically connected to a conductive container wall of the decompression container. 9. The plasma apparatus according to claim 8, wherein another high-frequency bias is applied to perform the surface treatment. 10. A protective film made of a dielectric material is provided on the conductive thin film, and the protective film has a capacity per unit area of a plasma sheath formed between the plasma and an inner surface of the decompression container. 10. The plasma device according to claim 9, wherein the thickness per unit area of the protective film is set to be equal to or less than the thickness. 11. The plasma device according to claim 9, wherein the high frequency applied to the antenna is amplitude-modulated. 12. A distance of at least 10 times the mean free path between electrons and gas molecules at a predetermined gas pressure is maintained between the plasma forming region by the high-frequency electromagnetic field and the substrate to be processed. The plasma device according to any one of claims 9 to 11, wherein: 13. The conductive thin film according to claim 8, wherein the conductive thin film has a thickness that allows the high-frequency electromagnetic wave to pass therethrough.
13. The plasma device according to any one of items 12 to 12. 14. The conductive thin film according to claim 8, wherein the conductive thin film includes a plurality of portions arranged along a transmission surface at a predetermined interval from each other so as to transmit the high-frequency electromagnetic wave. The high-frequency introducing member according to any one of the preceding claims. 15. A dielectric material having a relative dielectric constant of 10
The high frequency introducing member according to any one of claims 8 to 14, wherein the ceramic sintered material or the glass material is used.