JPH068510B2 - Plasma / ion generator and plasma / ion processing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a plasma / ion generation source and improvement in performance of a plasma / ion processing apparatus such as a plasma CVD apparatus or a plasma etching apparatus using the same, and The present invention relates to a plasma / ion generation source suitable for treating a large-area sample and a plasma / ion processing apparatus using the same.

[Prior Art] As a process technology for semiconductor manufacturing, a dry process has become a very important technology for miniaturization and high integration of semiconductor devices. In such a dry process, a plasma processing apparatus has recently been used which performs etching, deposition, ion implantation and the like using plasma ions. Further, as a new process technology for creating next-generation materials and modifying the surface characteristics of materials, the ion-plasma assist technology using such ion-plasma is drawing attention. Typical examples of these devices are a plasma CVD device, an ion shower etching device, a plasma flow etching device, an ion implantation device,
There are dynamic ion beam mixing equipment, ion assist deposition equipment, etc.

Fig. 7 shows the basic structure of a conventional plasma generation source using ECR discharge and an ECR CVD apparatus using it (eg J
pn.J.Appl.Phys.vol.22, no.4, (1983) L210-212).
In FIG. 7, reference numeral 1 denotes a plasma generation chamber, and a microwave (for example, 2.45 GHz) obtained from a microwave oscillation source (not shown) via an isolator and a matching device (not shown) is provided in the plasma generation chamber 1. A magnetic coil 4 for electron cyclotron resonance (ECR) is arranged around the plasma generation chamber 1, which is guided through the waveguide 2 and the microwave introduction window 3. A gas to be turned into plasma is introduced into the plasma generation chamber 1 through the gas inlet 5. Reference numeral 6 is a cooling water passage for guiding cooling water to the outer wall of the plasma generation chamber 1.

A plasma limiter 7 is provided at the bottom of the plasma generation chamber 1, and the plasma generated in the plasma generation chamber 1 is taken out as a plasma stream 8 through the plasma limiter 7 and placed on a sample table 10 arranged in a sample chamber 9. Lead to sample 11,
Reference numeral 12 is a gas inlet for the sample chamber 9. Reference numeral 13 is an exhaust system for evacuating the plasma generation chamber 1 and the sample chamber 9.

Gas is introduced into the plasma generation chamber 1 through the gas inlet 5, microwaves (for example, 2.45 GHz) are introduced through the waveguide 2, and the magnetic coil 4 is used to generate a DC magnetic field (875 Gauss) under electron cyclotron resonance (ECR) conditions. Is applied in the direction perpendicular to the microwave electric field, these interactions cause
The gas introduced into the plasma generation chamber 1 becomes plasma.
For example, when depositing SiO ₂ on a sample (Si wafer, etc.) 11, by introducing oxygen gas from the gas inlet 5 into plasma and introducing SiH ₄ from the gas inlet 12, A dense film is formed on the sample 11 at low temperature without heating the sample 11. When etching the SiO ₂ on the surface of the sample 11, the CF introduced through the gas inlet 5 is used.
The gas such as ₄ is turned into plasma and the sample 11 is irradiated to etch SiO ₂ .

Further, in the apparatus of FIG. 7, an ion extraction electrode is attached to the plasma extraction port by the plasma limiter 7 to extract only ions in the plasma, and the ion energy is controlled, so that this apparatus is an ion shower etching apparatus. Can also be used as

[Problems to be Solved by the Invention] Conventionally, the cavity of the plasma generation chamber by microwave excitation of this kind has a diameter of about 20 cm, which makes it possible to process an extremely large sample, for example, a length of about 1 m or more. Was difficult. In order to meet this demand, it is necessary to develop a large-diameter plasma deposition / etching device and a dynamic ion beam mixing device using a plasma generation source that generates a large-diameter plasma. To that end, it is essential to develop a plasma generation source that generates a large-diameter beam plasma.

However, in the plasma generation source as shown in FIG.
Even if the plasma generation chamber is simply enlarged to form a large-diameter plasma generation source, the electric field strength of microwaves becomes weaker in the surrounding area, and the propagation mode of microwaves becomes multiple modes, resulting in non-uniform electric field strength. Therefore, not only the plasma density is lowered, but also the condition for obtaining the uniformity becomes severe. Furthermore, even if an attempt is made to simply arrange a plurality of plasma generation sources to increase the area, since a relatively large magnetic circuit is used, it is necessary to make a gap between the plasma generation sources, and thus the plasma beam cannot be homogenized. It ’s difficult,
Alternatively, there is a problem that the plasma density is reduced.

That is, in the conventional ECR plasma generation source, uniform plasma cannot be obtained even if the cavity of the plasma generation chamber is enlarged,
There is a limit to obtaining a uniform and large-diameter beam. Furthermore, since the ECR plasma generation source uses a magnetic coil that generates a relatively large magnetic field, it was not possible to install the plasma generation source without making a gap, so even if multiple plasma generation sources are simply arranged. It was difficult to obtain a uniform and large-area plasma beam.

In order to deal with such a purpose, development of a plasma generation source that generates a uniform large-diameter plasma has become an important issue.

Therefore, an object of the present invention is to provide a plasma / ion generation source that generates uniform and large-diameter plasma / ions.

Another object of the present invention is to provide a plasma / ion processing apparatus capable of processing a large-area sample by using such a plasma / ion generation source.

[Means for Solving the Problems] In order to achieve such an object, the plasma generation source of the present invention is arranged in a plurality of rows, and includes a plurality of plasma generation units for generating plasma and a plurality of plasma generation units. A plasma coupling cavity through which a plurality of plasmas respectively generated in the generating section are guided; and a plasma coupling means for superposing the plasmas from the plasma generating sections in each of the plurality of rows in the plasma coupling cavity Is characterized by.

The plasma processing apparatus of the present invention is arranged in a plurality of rows,
A plurality of plasma generators for generating plasma, a plasma coupling cavity through which the plurality of plasmas generated by the plurality of plasma generators are guided, and plasmas from the plasma generators of each of the plurality of rows are generated. A plasma coupling means to be overlapped in the plasma coupling cavity, a sample chamber connected to the plasma coupling cavity, a sample chamber which is arranged in the sample chamber, and which is processed by the plasma from a plurality of plasma generation units can be placed. A sample table is provided, and plasma from a plurality of plasma generation units in each of a plurality of rows is superimposed and irradiated on the sample.

The ion generating source of the present invention includes a plurality of plasma generating units arranged in a plurality of rows to generate plasma, and a plasma coupling cavity for guiding the plurality of plasmas generated by the plurality of plasma generating units. , A plasma coupling means for superposing the plasmas from the plasma generating sections of each of the plurality of rows in the plasma coupling cavity, and an ion extraction electrode system for extracting ions from the plasma coupling cavity. .

The ion treatment apparatus of the present invention includes a plurality of plasma generation units arranged in a plurality of rows to generate plasma, and a plasma coupling cavity for introducing a plurality of plasmas generated by the plurality of plasma generation units. Connected to the plasma coupling cavity, a plasma coupling means for superposing the plasmas from the plasma generating sections of each of the plurality of columns in the plasma coupling cavity, an ion extraction electrode system for extracting ions from the plasma coupling cavity, A sample chamber and a sample table which is placed in the sample chamber and on which a sample to be treated by ions can be placed, so that ions from the ion extraction electrode system are superposed on the sample and irradiated. Is characterized by.

[Operation] According to the present invention, a plurality of ECR plasma generators for generating plasma are installed in two or more rows, and a plasma coupling means such as a magnetic circuit for superposing the plasmas of the plasma generators in different rows is provided. A uniform plasma / ion beam can be generated with a caliber. This makes it possible to make it equivalent to arranging a plurality of plasma / ion generation sources without leaving a gap therebetween and to control the degree of superposition of plasma / ions, so that the uniformity of the plasma beam and the ion beam can be improved. Moreover,
By doing this, one plasma / plasma of the ion generation source / plasma of about the same degree as the ion density /
Since the sample can be irradiated with the ion density, a large area sample can be processed at high speed.

Embodiments Embodiments of the present invention will be described in detail below with reference to the drawings.

Example 1 FIGS. 1 (A) and 1 (B) are configuration diagrams showing an example of the ECR plasma generation source of the present invention, and FIG. 1 (A) is a configuration diagram of the plasma generation source viewed from the side. , FIG. 1 (B) also shows a block diagram seen from above.

In FIGS. 1A and 1B, 21 indicates a plurality of ECR plasma generation parts. Each of the plasma generation units 21 may have a conventionally known configuration shown in FIG. 7, and includes a plasma generation cavity as the plasma generation chamber 1, a microwave introduction waveguide 2, a microwave introduction window 3, and a magnetic coil 4. , A gas inlet 5, a cooling water passage (not shown), and a plasma limiter 7.

Reference numeral 22 denotes a rectangular cavity portion for plasma coupling, and the plurality of plasma generation portions 21 are divided into two rows and arranged on the side surfaces of the cavity portion 22 which face each other. As a result, the plasma flow 23 taken out from the plasma limiter 7 of each plasma generation unit 21 is guided into the cavity 22. A magnetic coil 24 constituting a magnetic circuit for plasma coupling is arranged on the outer peripheral portion of the cavity 22 for plasma coupling, and each plasma flow 23 is deflected in the same direction, that is, the direction of the magnetic force line by the magnetic force line.

The ECR plasma generator 21 is a rectangular plasma coupling cavity 2
Two or more (in this example, a total of eight) are arranged on the side surfaces facing each other around the circumference of 2. For example, if the outer dimension of the ECR ion generating portion 21 in the column direction is 20 cm, the length of the plasma coupling cavity 22 in the column direction is about 90 cm. The magnetic coil 4 of the ECR plasma generator 21 is usually 2.45GHz
A magnetic field near 875 Gauss, which is the ECR condition for, is used, and a relatively large magnetic field is formed outside. In the present embodiment, such a magnetic coil 4 of the ECR plasma generation unit 21 is used.
The magnetic circuit 24 for plasma coupling is configured and arranged by generating the magnetic force lines orthogonal to the direction of the magnetic force lines of the magnetic field generated in 1. and determining the mutual polarities of the magnetic circuits 4 and 24 so that the directions of both magnetic force lines are continuous. Then, the plasma generated by the ECR plasma generating unit 21 is bent along the magnetic field lines for plasma coupling and in the direction of the magnetic field lines, and is superposed to form a combined plasma flow 27.

The magnetic circuit 24 for plasma coupling can be configured by, for example, a rectangular magnetic coil in which a conductive wire is wound in a rectangular shape in accordance with the shape of the plasma coupling cavity 22.

Since this embodiment has such a configuration, gas is introduced from the gas introduction port 5 into the plasma generation cavity 1 of the ECR plasma generation unit 21 and microwaves are introduced from the microwave introduction waveguide 2, and the magnet coil 4 is introduced. When a magnetic field is generated at, plasma is generated. The plasma flow 23 from the plasma generation cavity 1 thus generated is bent in the direction of the extraction electrode system 25 so as to overlap each other in the column direction by the action of the magnetic field generated in the plasma coupling magnetic circuit 24. . If there is no extraction electrode system 25, this superposed plasma stream 27 can be used as it is as a plasma generation source for plasma processing.

Alternatively, as shown in FIG. 1 (A), by disposing an ion extraction electrode system 25 on the downstream side of the superposed plasma streams 27, the ion beam 26 is extracted from the plasma and the ion energy is required. The energy can be controlled to In addition, in FIG. 1 (A),
As the ion extraction electrode system 25, a configuration example of three electrodes is shown, but various extraction electrodes such as two electrodes, one electrode, and a single leaf mesh electrode can be used depending on the ion energy to be controlled. .

In the present embodiment, since the plurality of plasma generating units are arranged in the form of a row in this manner, the plasma beam 27 or the ion beam 26 which is very long in the row direction is maintained without impairing the plasma density and its uniformity. Can be generated. In principle, by increasing the number of plasma generators 21,
The length of the beam in the column direction can be increased without limitation. Therefore, the present invention is, of course, effective for a sample long in one direction, and it is possible to process a sample having a large two-dimensional area by moving the sample in the other direction. Further, if each ECR plasma generation unit 21 generates a plasma corresponding to 200 mA, the eight plasma generation units 21 can constitute a large current plasma generation source that exceeds 1.5 A in total. Moreover, the uniformity of the beam can be controlled by appropriately setting the arrangement and position of the coupling magnetic circuit 24 and the strength of the magnetic field.

In FIG. 1 (A), the ion extraction electrode system 25
Although the example of the form of the ion source for generating the ion beam is shown by using, it is needless to say that the ion source can be used as the plasma generation source using the plasma flow 27 itself without providing the extraction electrode system.

Furthermore, in this embodiment, as shown in FIG.
The plasma generating portions 21 are arranged in two rows on substantially the same horizontal plane on the opposite side surfaces of the plasma coupling cavity 22, but a plurality of such horizontal planes are set and along each horizontal plane, as shown in FIG. 1 (A).
It is also possible to adopt a multi-tiered configuration in which the plasma generating units 21 are arranged in three rows or four rows or more in the configuration as shown in FIG.

Embodiment 2 FIGS. 2 (A) and 2 (B) are one embodiment of the plasma processing apparatus of the present invention, and are configuration examples of a plasma CVD apparatus / ion flow etching apparatus using the plasma generation source of Embodiment 1 of the present invention. Is. In FIG. 2 (A), the structures of the plasma limiter 7 and the sample chamber provided below the plasma coupling cavity 22 are the same as those of the conventional example of FIG. Reference numeral 56 is window glass for introducing light into the cavity 22, and reference numeral 57 is light such as ultraviolet rays and infrared rays.

The plasmas generated by the plurality of plasma generation units 21 arranged in a row are overlapped with each other in the cavity 22 for plasma coupling, and the combined plasma flow 27 having a high plasma density is directed toward the sample stage 10. Be transported to.

Alternatively, by installing an extraction electrode system instead of the plasma limiter 7, it is possible to extract ions and control the energy thereof.

By placing various samples 11 on the sample table 10, plasma processing such as deposition and etching, and ion beam processing can be performed.

For example, various gases such as inert gases, hydrides, halides, organometallic compound gases (Ar, Kr, H ₂ , O ₂ , SiH ₄ , GeH
_4, using _{AsH 3, GaR 3, AR 3} , CF 4 , etc.), an insulating film, a metal film, compound _{(Si, SiO 2, Si 3} N 4, Ge, A, a film forming or etching of the GaAs, etc.) It can be carried out. According to this device, as described above, the generated plasma flow or ion beam can have a large beam diameter in the column direction, so that a very large sample can be processed.
It is especially effective for the processing of samples exceeding 100. That is, according to this example, uniform plasma treatment can be performed in one direction, and therefore, by moving the sample 11 in the other direction as indicated by the arrow, a high-quality film is formed on a large-area sample. Alternatively, the surface can be modified by etching with high precision or by irradiating with ions of high ion energy.
For example, it is effective when an insulator of SiO ₂ or Si ₃ N ₄ is attached to the surface of a large area of stainless steel, iron or plastic at a low temperature to improve the corrosiveness and wear resistance. Moreover,
Since the plasma processing is performed using the plurality of plasma generation units 21 without lowering the plasma density, the processing can be performed at high speed.

Alternatively, as shown in FIG. 2 (A), by irradiating the sample 11 with light 57 such as ultraviolet rays or infrared rays through the window glass 56, the temperature of the sample surface is raised or the surface reaction is promoted. Or remove surface stains to add more sophisticated treatments.

Although FIG. 2 (A) shows an example in which the plasma flows 23 from the respective ECR plasma generating parts 21 are bent at right angles to be combined,
Generally, the smaller the deflection angle is, the easier the plasma flows are superimposed. Therefore, FIG. 3 shows a specific example of a configuration in which the deflection angle is reduced. In FIG. 3, reference numeral 28 denotes a plasma coupling cavity, which is formed with an inclined taper surface on the upper part thereof, and a plurality of ECR plasma generation portions 21 are formed on the taper surface.
Is provided to make the deflection angle of the plasma flow 23 smaller than 90 degrees. In this embodiment, the rest of the configuration and operation are exactly the same as in FIG. Further, in FIG. 3, as a method of supplying gas to the sample chamber 9, the gas supply mechanism 29 is arranged near the sample 11 so that the gas is uniformly supplied to the vicinity of the sample 11.

Embodiment 3 FIG. 4 shows another embodiment of the present invention, in which reference numeral 31 is a plasma generation part which has no magnetic lines of force in the plasma traveling direction or which generates plasma with a weak magnetic field. 32 is the plasma flow 23 taken out from the plasma generation unit 31
Is an auxiliary magnetic circuit for controlling. Here, the direction of the magnetic lines of force of the auxiliary magnetic circuit 32 for plasma control is the direction in which plasma is drawn out from the cavity 22 for plasma coupling, that is, the direction of the magnetic lines of force of the magnetic circuit 24 for plasma coupling is orthogonal, and the directions of both magnetic lines of force. Magnetic circuits 24 and 32 so that
The mutual polarities of The rest of the configuration and operation of this embodiment are exactly the same as in the case of FIGS. 2A and 2B, and the plasma flow 33 generated by the plasma generation unit 31 by the action of these magnetic fields is the magnetic circuit 24. The combined plasma flow is bent in the direction of the lines of magnetic force due to
As sample 27, the sample 11 is irradiated and processed.

Fourth Embodiment FIG. 5 is a diagram showing the configuration of a fourth embodiment of the present invention. In order to increase the number of plasma generating parts, in addition to the basic configuration of FIGS. 2 (A) and (B), This is an example in which a plasma generation unit 41 is added. That is, here, one or a plurality of plasma generation units 41 having the same configuration as the ECR plasma generation unit 21 are used.
Are arranged in rows on the upper surface of the plasma coupling cavity 22. It should be noted that the plasma generating unit 41 can be configured in the same manner even if a plasma generating unit of another form is used.

In FIG. 5, the direction of the lines of magnetic force by the magnetic circuit 4 of the ECR plasma generation unit 21 is perpendicular to the direction of the lines of magnetic force of the magnetic circuit 24 for plasma coupling, as in the configuration of FIGS. 2 (A) and (B). , And the magnetic circuits 24 and 4 so that the magnetic lines of force of both sides are continuous.
The mutual polarities of are determined. On the other hand, ECR plasma generator 4
The magnetic circuit 4 of No. 1 is configured such that the direction of the magnetic lines of force thereof does not match the direction of the magnetic lines of force of the magnetic circuit 4 of the ECR plasma generating unit 21, that is, the magnetic circuit 4 is not continuous but repels. As in the case of the configuration of FIGS. 2 (A) and (B),
The plasma flow 23 from the plasma generation unit 21 is bent so as to overlap in the direction of the extraction electrode system 25. Further, the plasma from the plasma generation unit 41 goes straight as a plasma stream 42 so as not to diverge due to the magnetic field from the magnetic circuit 4 of the plasma generation unit 21. These plasma streams 23 and 42 join together to irradiate the sample 11 as a combined plasma stream 43. In this embodiment, the processing can be performed using the plasma having the increased plasma density and ion current.

Embodiment 5 FIG. 6 shows still another embodiment of the present invention.
A magnetic circuit 61 for plasma coupling is installed below the sample table 10. Although an example of a permanent magnet is shown as the magnetic circuit 61 in FIG. 6, it goes without saying that a magnetic coil may be used.
Similar to the above-described embodiment, the plasma generated by the plasma generation unit 21 is sampled along the magnetic lines of force by the magnetic circuit 61.
Bent as a combined plasma stream 27 in the direction of 11 to illuminate the sample 11. This configuration has an advantage that the magnetic circuit 61 for plasma coupling can be easily configured by a permanent magnet, and since the position of the magnetic circuit 61 can be easily moved, it is possible to uniformly move the magnetic circuit 61 during plasma processing. Can be further improved.

[Effects of the Invention] As described above, according to the present invention, by arranging a plurality of plasma generating units in the form of rows, it is possible to generate a uniform large-diameter plasma beam / ion beam.
A large area sample with a length of 1 m or more can be processed. Moreover, since the structure is suitable for generation of high-density plasma / ion beam, high-speed processing is possible. INDUSTRIAL APPLICABILITY The plasma / ion processing apparatus of the present invention is extremely effective when used for performing plasma / ion applied plasma deposition, etching, ion beam dynamic mixing, and ion assisted deposition.

Furthermore, the present invention can be effectively applied to the plasma / ion generation source and the plasma / ion processing apparatus for ion doping, cleaning of the semiconductor surface, and the like.

Furthermore, the plasma / ion generation source of the present invention is extremely effective when used in a plasma processing apparatus such as ion doping and semiconductor surface cleaning.

Note that the present invention is not limited to the plasma generation source and the plasma processing apparatus using the same, and the ion generation source is configured by simply adding the ion extraction electrode system to the plasma generation source as described above, or It is clear that an ion processing apparatus using the ion generation source can be configured, and the plasma generation source and the plasma processing apparatus here are to be broadly interpreted to include not only plasma but also ions. .

[Brief description of drawings]

1 (A) and 1 (B) are configuration diagrams showing one embodiment of the plasma / ion generation source of the present invention, FIGS. 2 (A) and (B), FIG. 3, FIG. 4, FIG. FIG. 6 is a block diagram showing various embodiments of the plasma / ion treatment apparatus of the present invention, and FIG. 7 is a block diagram showing a configuration example of a conventional ECR CVD apparatus. DESCRIPTION OF SYMBOLS 1 ... Plasma generation chamber (cavity for plasma generation), 2 ... Microwave introduction window, 3 ... Waveguide, 4 ... Magnetic coil, 5, 12, 29, 51 ... Gas introduction port, 6 ... Cooling water passage, 7 ... Plasma limiter, 8 ... Plasma flow, 9 ... Sample chamber, 10 ... Sample stage, 11 ... Sample, 13 ... Exhaust system, 21, 41 ... ECR plasma generation part, 22, 28 ... Plasma coupling cavity part, 23, 42 ... Plasma flow, 24, 61 ... Magnetic circuit for plasma coupling, 25 ... Extraction electrode system, 26 ... Ion beam, 27, 43 ... Combined plasma flow, 31 ... Plasma generation source, 32 ... Auxiliary magnetic circuit for plasma control, 56 … Window glass, 57… ultraviolet light, infrared light, etc.

Claims (4)

[Claims] 1. A plurality of plasma generation units arranged in a plurality of rows to generate plasma, and a plasma coupling cavity for guiding the plurality of plasmas generated by the plurality of plasma generation units, respectively. Plasma generating means for superposing the plasmas from the plasma generating sections of each of the plurality of rows in the plasma coupling cavity. 2. A plurality of plasma generation units arranged in a plurality of rows to generate plasma, and a plasma coupling cavity for guiding the plurality of plasmas generated by the plurality of plasma generation units, respectively. Plasma coupling means for superposing plasmas from the plasma generation units of each of the plurality of columns in the plasma coupling cavity, a sample chamber connected to the plasma coupling cavity, and arranged in the sample chamber, A sample table on which a sample to be processed by the plasma from the plurality of plasma generating units can be placed, and the plasma from the plurality of plasma generating units in each of the plurality of rows is superimposed on the sample. The plasma processing apparatus is characterized in that it is irradiated with light. 3. A plurality of plasma generation units arranged in a plurality of rows to generate plasma, and a plasma coupling cavity for guiding the plurality of plasmas generated by the plurality of plasma generation units, respectively. It is characterized by comprising plasma coupling means for superposing plasmas from the plasma generating units of each of the plurality of columns in the plasma coupling cavity, and an ion extraction electrode system for extracting ions from the plasma coupling cavity. Ion source. 4. A plurality of plasma generation units arranged in a plurality of rows to generate plasma, and a plasma coupling cavity for guiding the plurality of plasmas generated by the plurality of plasma generation units, respectively. Plasma coupling means for superposing the plasmas from the plasma generating units of each of the plurality of columns in the plasma coupling cavity, an ion extraction electrode system for extracting ions from the plasma coupling cavity, and the plasma coupling cavity A sample chamber connected to the sample chamber, and a sample table that is placed in the sample chamber and on which a sample to be treated by ions can be placed. Ions from the ion extraction electrode system are superposed on the sample and irradiated. An ion treatment device characterized by the above.