JPH05125547A - Plasma treating device - Google Patents

Abstract

PURPOSE:To provide a high-performance plasma treating device which is reduced the damage by ion bombardment and capable of treating a substrate at a high rate. CONSTITUTION:Double cylinder-shaped electrodes 9 and 10 coaxial and parallel with each other are arranged at the periphery in a treating chamber 1 capable of being evacuated, a high-frequency voltage can be impressed between the electrodes from a power source 11, an inlet pipe 6 is arranged to supply at least one kind of the treating gases into a plasma producing discharge chamber 8 formed between the electrodes 9 and 10, and a permanent magnet 12 for generating a vertical magnetic field in the discharge chamber is set outside the treating chamber 1. The electrode 9 is pierced with plural holes and grounded and functions as a high-frequency shield. A substrate 2 to be treated is placed on its support 3, and a second treating gas is introduced through a pipe 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus used for manufacturing semiconductor elements, electronic circuits and the like, and more particularly to a plasma processing apparatus capable of performing high-performance and high-speed processing with less ion bombardment.

[0002]

2. Description of the Related Art A plasma processing apparatus occupies an important position in a VLSI manufacturing process among semiconductor device and electronic circuit manufacturing processes. SiN for final protective film
Plasma C for forming a thin film of SiO ₂ or the like for the interlayer insulating film
A VD device, a sputtering device for forming a thin film of Al for wiring, a RIE device for etching various thin films, and a plasma ashing device for ashing the photoresist layer are used. Applications to cleaning, doping, epitaxial processes, etc. have also been studied. Most of the plasma processing apparatuses that have been put into practical use use a high frequency of 13.56 MHz or a microwave of 2.45 GHz as an excitation source and generate 1 × 10 ¹⁰ / cm 2.
Plasma treatment is performed by contacting the substrate with plasma having a density of ³ or more.

[0003]

However, in the above-mentioned prior art, a large number of ions in the plasma are accelerated by the sheath electric field formed on the contact surface between the substrate and the plasma, and the kinetic energy is about several tens to 100 eV. Since the light enters the substrate, the surface of the substrate is likely to be damaged.
When an organic source gas is used, inappropriate reaction such as dissociation of C—H bond occurs, and carbon is likely to be mixed in the formed film.

In order to solve these problems, a remote plasma processing apparatus in which a plasma generating chamber and a plasma processing chamber are separated has been studied and a treatment with less damage is possible. Are spatially separated, the excited species effective for the reaction are likely to be deactivated by collision during transportation, the treatment is incomplete (the density is low in the case of film formation), and the treatment speed is low. , Etc.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art and to provide a plasma processing apparatus capable of processing a substrate at a high speed and with high performance, with less damage due to ion bombardment. Is.

[0006]

According to the present invention, in order to achieve the above objects, a processing chamber, a means for exhausting the processing chamber, and a means for supplying a processing gas into the processing chamber. And plasma generating means for supplying a high frequency wave between double cylindrical electrodes which are coaxial and parallel to each other and which are arranged on the outer periphery of the processing chamber, and means for holding the substrate to be processed in the processing chamber. A plasma processing apparatus is provided.

In the present invention, means for generating a magnetic field perpendicular to the electric field can be provided between the double cylindrical electrodes. Further, as the inner electrode of the double cylindrical electrodes, an electrode having a plurality of holes and grounded to function as a high frequency shield can be used.
Furthermore, it is preferable to supply at least one of the processing gases between the double cylindrical electrodes.

According to the present invention, among the double cylindrical high frequency electrodes, a plurality of holes can be opened in the inner electrode and grounded to function as a high frequency shield for the space around the substrate to be processed. Reduces the plasma density near the substrate to be treated to reduce damage to the substrate due to ion bombardment, and also generates a magnetic field perpendicular to the electric field between the double cylindrical high frequency electrodes to localize near the electrodes. By generating a high-frequency magnetron discharge and passing at least one kind of the processing gas through the high-density plasma portion formed between the double cylindrical electrodes, a large amount of excited species effective for the reaction can be obtained. It can be transported to a nearby area for higher performance and faster processing.

As the high frequency used in the device of the present invention, an appropriate value in the range of 1 to 300 MHz can be selected. The magnetic flux density in the vicinity of the high frequency electrode is 100 to 1000 G depending on the required degree of plasma localization.
An appropriate value of can be selected. The magnetic field generating means may be a permanent magnet or an electromagnet. As the processing gas supply means, one in which the introduction hole of the ring-shaped introduction tube comes into contact with the plasma, or one in which the gas is supplied between the two coaxial cylindrical tubes whose tips come into contact with the plasma is suitable. is there. Despite the plasma isolation from the substrate in order to achieve low damage, the gas excitation efficiency is increased and a large amount of excited reactive species for the reaction is supplied to the substrate, resulting in high-speed and high-performance processing. Will be possible.

Furthermore, if the present invention is applied to a photo-assisted plasma processing apparatus that irradiates the surface of the substrate with visible ultraviolet light absorbed by the substrate or a reaction intermediate attached to the substrate, a high-performance treatment can be performed at a still lower temperature. It will be possible.

FIG. 1 is a schematic view showing a first structural example of a plasma processing apparatus according to the present invention.

In FIG. 1, the processing chamber 1 is evacuated by an exhaust means (not shown) through a conductance valve (not shown).
Is possible. The processing chamber has a cylindrical shape having a vertical direction. A support 3 for supporting the substrate 2 to be processed is arranged in the lower part of the processing chamber 1. A heater 4 for heating the substrate 2 is built in the support. A first ring-shaped introduction pipe 6 for supplying the first processing gas and a second ring-shaped introduction pipe 7 for supplying the second processing gas are arranged in the processing chamber 1. The processing gas is supplied into the processing chamber 1 through the introduction holes formed in these pipes.

A cylindrical porous shield electrode 9 and a cylindrical high-frequency electrode 10 are coaxially arranged in the upper part of the processing chamber 1, and a ring-shaped discharge chamber 8 is formed between these two electrodes. There is. A high frequency power supply 11 applies a high frequency voltage between these two electrodes 9 and 10. The direction of this electric field is the horizontal direction and the radial direction of the processing chamber.
The shield electrode 9 is grounded. High frequency electrode 10
A permanent magnet 12 for forming a vertical magnetic field perpendicular to the electric field is arranged around the outer periphery of the upper part of the processing chamber 1.

When using the apparatus of this configuration example, the substrate 2
Is fixedly held on the support 3, and a current is passed through the heater 4 to raise the temperature of the substrate 2 to a desired temperature (for example, room temperature to several hundreds of degrees Celsius). Then, the first processing gas is supplied from the first introduction pipe 6 into the discharge chamber 8, and the second processing gas is directly supplied from the second introduction pipe 7 to the vicinity of the substrate 2. And the processing chamber 1
To the desired degree of vacuum (for example, 1 mTorr to 1 Tor)
The pressure is reduced to r) and the high frequency power source 11 is used to
A desired high frequency (for example, electric power of several tens to several thousands W) is applied to the electrode 10 to generate a high frequency electric field in the discharge chamber 8 in the presence of a magnetron magnetic field (for example, magnetic flux density of several hundred G) by the magnet 12 to generate an electric field. A localized plasma is generated in the vicinity of. Thus, the first processing gas is turned into plasma in the discharge chamber 8 and a large amount of excited species effective for the reaction is supplied to the vicinity of the substrate 2. By thus supplying the processing gas for an appropriate time, the substrate 2 can be processed as desired.

FIG. 2 is a schematic diagram showing a second configuration example of the plasma processing apparatus according to the present invention. 2, the same members as those in FIG. 1 are designated by the same reference numerals.

In this configuration example, an optical assist function is added to the plasma processing apparatus of FIG. That is, a window 16 is attached to the upper part of the processing chamber 1, and a light source 13, an integrator 14 and a collimator lens 15 are arranged as means for irradiating the substrate to be processed in the processing chamber 1 with light. In the present configuration example, in addition to the operation in the case of FIG. 1 described above, visible light of appropriate intensity is emitted from the light source 13.

[0017]

EXAMPLES Examples of plasma processing using the apparatus of the present invention will be described below.

(Embodiment 1) This embodiment is an example in which the apparatus shown in FIG. 1 is applied to a plasma CVD apparatus. In the present example, a Si substrate was used as the substrate 2, the source gas N ₂ was supplied as 200 sccm as the first processing gas, and the source gas SiH ₄ was supplied as 20 sccm as the second processing gas.
Pressure in the processing chamber 1 is 0.1 Torr, substrate temperature is 300 ° C.,
Si under the conditions of high-frequency power of 200 W and magnetic flux density of 130 G
An N film was formed.

As a result, a good quality SiN film having a hydrogen content of 10 atm% and a compressive stress of 2 × 10 ⁹ dyn / cm ^{2 was formed at} a high speed of 70 nm / min with little damage.

In this embodiment, N is used as the source gas.₂ And S
iH_FourWas used to form a SiN film, but the source gas was changed
By changing the film formation conditions as needed,
SiO ₂ , Ta₂ O_Five , Al₂ O₃ , AlN etc. insulation film
And semiconductor films such as a-Si, poly-Si and GaAs
Alternatively, a metal film of Al, W, or the like can be formed.

(Embodiment 2) This embodiment is an example in which the apparatus shown in FIG. 1 is applied to a surface modification treatment apparatus. In this example, a Si substrate was used as the base body 2, and 200 sccm of O ₂ for oxidation treatment was supplied as the first treatment gas. The surface was oxidized under the conditions of a pressure of 0.2 Torr in the processing chamber 1, a substrate temperature of 500 ° C., a high frequency power of 500 W, and a magnetic flux density of 130 G.

As a result, a high-quality S having a breakdown voltage of 11 MV / cm
The iO ₂ film was formed at a high speed of 1.5 nm / min with an interface charge density of 4 × 10 ¹⁰ / cm ² and less damage.

In the present embodiment, the surface oxidation of Si was carried out using O ₂ as the processing gas. However, an appropriate combination of the substrate and the processing gas may be adopted, and the processing conditions may be changed as necessary. Due to Si, Al, Ti, Zn, Ta
It is possible to perform oxynitridation of B, As, P, etc.

(Embodiment 3) This embodiment is an example in which the apparatus shown in FIG. 1 is applied to a surface cleaning processing apparatus.
In this embodiment, a Si substrate is used as the substrate 2, and NF ₃ + H ₂ for cleaning processing is used as N as the first processing gas.
F ₃ 50 sccm and H ₂ 200 sccm were supplied. The cleaning process was performed under the conditions of a pressure of 0.2 Torr in the processing chamber 1, a substrate temperature of 300 ° C., a high frequency power of 300 W, and a magnetic flux density of 130 G.

As a result, the natural oxide film on the Si substrate could be completely removed in 1 minute.

In this embodiment, NF ₃ + is used as the processing gas.
Although the surface of Si was cleaned using H ₂ , the surface cleaning treatment of organic substances, heavy metals, etc. can be performed by adopting an appropriate combination of the substrate and the treatment gas and appropriately changing the treatment conditions as necessary. It is possible.

(Embodiment 4) This embodiment is an example in which the apparatus shown in FIG. 2 is applied to a photo-assisted plasma CVD processing apparatus. In this embodiment, a Si substrate is used as the base 2,
The source gas O ₂ is 500 scc as the first processing gas.
m, and a raw material gas TEOS (tetraethyl orthosilicate) was supplied at 100 sccm as the second processing gas.
Pressure in the processing chamber 1 is 0.1 Torr, substrate temperature is 300 ° C.,
A SiO ₂ film was formed under the conditions of light illuminance of 0.6 W / cm ² , high frequency power of 500 W, and magnetic flux density of 130 G.

As a result, good-quality flat Si having a hydrogen content of 1 atm% or less and a tensile stress of 2 × 10 ⁸ dyn / cm ² was obtained.
The O ₂ film was formed at a high speed of 180 nm / min.

In this embodiment, O ₂ and T are used as source gases.
An SiO ₂ film was formed using EOS, but an insulating film such as SiN, Ta ₂ O ₅ , Al ₂ O ₃ or AlN was formed by changing the source gas and appropriately changing the film forming conditions as needed. Alternatively, a semiconductor film such as a-Si, poly-Si, or GaAs, or a metal film such as Al or W can be formed.

[0030]

As described above, according to the present invention,
Since plasma generating means for supplying a high frequency is provided between the coaxial and parallel double cylindrical electrodes arranged in the outer peripheral portion of the processing chamber, at least one kind of processing gas is provided between these double cylindrical electrodes. Is supplied to generate a plasma at a position distant from the substrate to be processed, the plasma density in the vicinity of the substrate to be processed can be reduced, damage to the substrate due to ion bombardment can be reduced, and an effective excited species for processing can be obtained. It can be quickly transported to the vicinity of the substrate, and the substrate can be processed with high performance and high speed.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a first configuration example of a plasma processing apparatus according to the present invention.

FIG. 2 is a schematic diagram showing a second configuration example of the plasma processing apparatus according to the present invention.

[Explanation of symbols]

 1 processing chamber 2 substrate 3 support 4 heater 5 exhaust 6 processing gas introduction pipe 7 processing gas introduction pipe 8 discharge chamber 9 porous shield electrode 10 high frequency electrode 11 high frequency power supply 12 permanent magnet 13 light source 14 integrator 15 collimator lens 16 window

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H05H 1/46 9014-2G

Claims (4)

[Claims] 1. A processing chamber, a means for exhausting the processing chamber, a means for supplying a processing gas into the processing chamber, and dual coaxial, parallel to each other arranged on an outer peripheral portion of the processing chamber. A plasma processing apparatus comprising: a plasma generating means for supplying a high frequency wave between the cylindrical electrodes; and a means for holding a substrate to be processed in the processing chamber. 2. The plasma processing apparatus according to claim 1, further comprising means for generating a magnetic field perpendicular to the electric field between the double cylindrical electrodes. 3. The inner electrode of the double cylindrical electrode is provided with a plurality of holes and is grounded to function as a high frequency shield. The plasma processing apparatus according to 2. 4. The plasma processing apparatus according to claim 1, wherein at least one kind of the processing gas is supplied between the double cylindrical electrodes.