JPH11106929A - Plasma processing equipment - Google Patents

Abstract

(57) [Problem] To prevent adhesion and deposition of foreign matter such as a polymer film around a partition plate and its hole, around a gas supply port and inside a supply pipe. SOLUTION: A plasma chamber 2 in which plasma is generated by an excitation source using a gas, a processing chamber 1 in which a sample 7 is arranged, and a processing chamber provided between the plasma chamber and the processing chamber. A plasma processing apparatus comprising: a partition plate 3 having a hole 4 communicating with the plasma chamber; vacuum exhaust means for exhausting the processing chamber; and gas supply means 8, 9, and 10 for supplying gas to the plasma chamber in a pulsed manner. And means for maintaining at least one of the gas supply means at a temperature higher than the inner wall of the plasma chamber. A means for heating at least one of the partition plate and the gas supply means or a means for cooling the plasma chamber is provided.

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, and more particularly, to a plasma processing apparatus for forming a thin film on the surface of an object to be processed or etching the surface of the object using plasma. About.

[0002]

2. Description of the Related Art In recent years, the diameter of an object to be processed by a plasma processing apparatus has been increased, and a technique for uniformly processing the object having a large diameter has been demanded. In order to meet this demand, it is necessary to increase the area of the plasma.

FIGS. 4 and 5 show, for example, JP-A-7-263.
FIG. 1 is a schematic cross-sectional configuration diagram showing a conventional plasma processing apparatus described in JP-A-353-353. The plasma processing apparatus shown in FIG. 4 is, for example, a dry etching apparatus using electron cyclotron resonance plasma. In the figure, 1 is a processing chamber which is a space below the chamber, 2 is a plasma chamber which is a space above the chamber, 3 is a partition plate that separates the processing chamber 1 and the plasma chamber 2 in the chamber, and 4 is a partition plate 3 , An exhaust port, 6 a stage, 7 a sample, 8 a gas valve, 9 a driving device, 10 a gas introduction tube, 11 a waveguide, 12 a microwave introduction window, and 13 a magnetic field. Coil.

A processing chamber 1 has a stage 6 on which a sample 7 is mounted.
Is installed. The plasma chamber 2 is installed above the processing chamber 1, and a microwave is introduced from a waveguide 11 through a microwave introduction window 12. An etching gas is supplied to the plasma chamber 2 via a gas introduction pipe 10 and a pulse gas valve 8. The pulse gas valve 8 is controlled by a driving device 9 and supplies an etching gas to the plasma chamber 2 in a pulsed manner. The partition plate 3 separates the plasma chamber 2 from the processing chamber 1 and has a hole 4. The exhaust port 5 is connected to an exhaust system (not shown), and evacuates the processing chamber 1. A magnetic field coil 13 for applying a magnetic field to the plasma chamber 2 is provided near the plasma chamber 2.

In the plasma processing apparatus constructed as described above, the etching gas introduced into the plasma chamber 2 from the pulse gas valve 8 is exhausted from the hole 4 of the partition plate 3 through the processing chamber 1 and from the exhaust port 5. You.

At this time, when a microwave of 2.45 GHz is introduced into the plasma chamber 2 and a magnetic field of 875 Gauss is formed in the plasma chamber 2 by the magnetic field coil 13, an electron cyclotron resonance plasma is generated. The generated plasma is transported from the hole 4 of the partition plate 3 to the processing chamber 1 to etch the sample or to perform CVD (Chemical Vapor Decomposition).
Processing can be performed.

The pulse gas valve 8 is turned on and off by a signal from the drive unit 9. Pulse gas valve 8 is O
During the opening in the N state, an etching gas is introduced and O
While closed in the FF state, the supply of the etching gas is stopped.

If the evacuation capacity of the evacuation system is constant, the pressures of the plasma chamber 2 and the processing chamber 1 change with time as the pulse gas valve 8 operates. When the pulse gas valve 8 is turned on and the etching gas is introduced, the pressure in the plasma chamber 2 temporarily rises, and a state in which the pressure difference from the processing chamber 1 becomes large is realized.

Therefore, even if the hole 4 of the partition plate 3 is made large and a large number of holes 4 are provided in a wide range in order to guide a large-area plasma to the processing chamber 1 corresponding to a large-diameter sample, a steady state is obtained. The pressure difference between the plasma chamber 2 and the processing chamber 1 can be kept large as compared with the gas supply.

FIG. 5 shows a structure similar to that of the etching apparatus shown in FIG. 4, except that the waveguide 11, the microwave introduction window 12 and the magnetic field coil 13 are omitted, and an RF power applying means 270 is provided. Have been. Also, the side wall 2 of the plasma chamber 2
Reference numeral 71 is formed of a dielectric material such as quartz.

The RF power application means 270 includes the RF coil 27
2 is provided with a plasma RF power supply 277 that applies RF power to the RF power supply 2, and the RF coil 272 is arranged around the side wall 271. The RF coil 272 is formed of a conductor 273 and a first insulator 274 that covers the conductor 273.
2 is further covered with a conductive material 275 of a metal thin film, and the periphery thereof is covered with a second insulator 276.

When an etching gas is introduced from the pulse gas valve 8 into the plasma chamber 2 and RF power is applied to the RF coil 272, plasma is generated in the plasma chamber 2. In this case, the thickness D of the conductive material 275 is defined as D = (2
πfμσ) ^-1/2 (where f is the frequency of the RF power, μ is the magnetic permeability in vacuum, and σ is the conductivity of the metal thin film), it is RF-coupled to the plasma in the plasma chamber 2 However, it cannot be connected because it is shielded by the conductive material 275 in terms of direct current.

In this case, discharge starts from the surface of the side wall 271 of the plasma chamber 2 by induction coupling, and is coupled with the generated plasma. On the other hand, since the RF coil 272 is shielded, a DC electric field caused by a DC potential difference generated at both ends of the RF coil 272 is suppressed. As a result, the side wall 271 of the plasma chamber 2 is suppressed from being sputtered, and since no electrodes are present in the plasma chamber 2, clean plasma free of metal contamination is generated.

[0014]

The conventional plasma processing apparatus is configured as described above, and when a gas (such as a CF system) that easily forms a polymer film is used as in the etching of a Si oxide film, There was a possibility that such a polymer film adhered to the hole of the partition plate, but there was a possibility that such a polymer film adhered or deposited on the hole in the partition plate because no countermeasure was taken so far. In such a case, there is a high possibility that the hole in the partition plate is clogged, the size of the hole is varied, and the etching process becomes unstable. In addition, there is a possibility that those polymer films may be peeled off during the etching process, and the generation of dust due to them may easily become a problem.

[0015] It is also important to supply a stable pulsed gas. However, regarding the gas supply, no countermeasures have been taken against the adhesion and deposition of foreign substances such as a polymer film around the supply port and inside the supply pipe. In addition, there is a possibility that the supply of a stable etching gas may be impaired, and there is a concern that dusts may be generated due to the damage.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and suppresses the adhesion and deposition of foreign substances such as a polymer film around a partition plate and its holes, around a supply port and inside a supply pipe. The purpose of the present invention is to keep the size and arrangement of the holes provided in the holes constant and to supply a stable pulse of an etching gas. Further, it is another object of the present invention to suppress generation of dust due to peeling of the polymer film adhered and deposited.

[0017]

According to the present invention, there is provided a plasma processing apparatus comprising: a plasma chamber in which a plasma is generated by an excitation source using a gas; a processing chamber in which a sample is disposed; A partition plate provided between the plasma chamber and a hole communicating with the processing chamber from the plasma chamber; a vacuum exhaust unit for exhausting the processing chamber; and a gas supply unit for supplying the gas in a pulsed manner to the plasma chamber. And a means for maintaining at least one of the partition plate and the gas supply means at a higher temperature than the inner wall of the plasma chamber.

Further, there is provided means for heating at least one of the partition plate and the gas supply means, and at least one of the partition plate and the gas supply means is kept at a higher temperature than the inner wall of the plasma chamber.

Further, the plasma chamber is provided with means for cooling, and at least one of the partition plate and the gas supply means is kept at a higher temperature than the inner wall of the plasma chamber.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. Hereinafter, an embodiment of a plasma processing apparatus of the present invention will be described with reference to the drawings using an etching apparatus as an example. FIG. 1 is a sectional view schematically showing a plasma processing apparatus according to the first embodiment. In the figure, a processing chamber 1 is provided with a stage 6 on which a sample 7 is placed. The plasma chamber 2 is installed above the processing chamber 1 with the partition plate 3 interposed therebetween, and microwaves are introduced from the waveguide 11 through the microwave introduction window 12. The partition plate 3 is provided with a plurality of holes 4. The upper part of the plasma chamber 2 is provided with a pulse gas valve 8 that is turned on and off by a driving unit 9, and the etching gas is supplied from a gas introduction pipe 10 to the pulse gas valve 8.
Is supplied via A magnetic field coil 13 for applying a magnetic field to the plasma chamber 2 is provided near the plasma chamber 2. Pulse gas valve 8 and gas introduction pipe 1 near it
Heating means consisting of, for example, a heater wire 14 is provided at 0, and heating means consisting of, for example, a heater wire 15 is provided at the partition plate 3, and is kept at a higher temperature than the inner wall of the plasma chamber 2.

In the above configuration, the etching gas supplied to the plasma chamber 2 from the gas introduction pipe 10 via the pulse gas valve 8 passes through the hole 4 provided in the partition plate 3 and the processing chamber 1 It is led to. After that, the air is exhausted from the exhaust port 5 to the outside. To discharge the etching gas to the outside, the processing chamber 1 is evacuated by a vacuum pump (not shown). The processing chamber 1 is maintained at a higher vacuum than the plasma chamber 2.

An etching gas is introduced into the plasma chamber 2 from a pulse gas valve 8, and a microwave is introduced from a waveguide 11 through a microwave introduction window 12. Magnetic field coil 13
When a magnetic field is formed in the plasma chamber 2 by the above, plasma is generated in the plasma chamber 2. The generated plasma is introduced into the processing chamber 1 from each hole 4 of the partition 3 and etches the sample 7.

At this time, a polymer film may be formed by the etching gas in the plasma chamber 2, but generally, the adhesion coefficient when foreign matter adheres to the material surface decreases with an increase in temperature. Therefore, in the present embodiment, the partition plate 3, the pulse gas valve 8, and the gas introduction pipe 10 are connected to the heater wire 14,
Since the temperature is kept higher than the inner wall of the plasma chamber 2 by 15, the entire inner wall of the plasma chamber 2 can be regarded as a cold trap, and the adhesion of the polymer film to the partition plate 3, the pulse gas valve 8 and the gas introduction pipe 10. -Deposition can be suppressed.
Therefore, a stable supply of the pulse gas and a stable etching process can be obtained. In addition, since adhesion and deposition of the polymer film on the partition plate 3 and the like can be suppressed, contamination of the processing chamber 1 due to dust generated by peeling of the polymer film and the like can be reduced.

The first condition is that the temperature of the partition plate 3, the pulse gas valve 8 and the gas introduction pipe 10 is higher than that of the plasma chamber 2, and the partition plate 3 is subjected to a plasma treatment or an apparatus (for example, vacuum sealing characteristics). The temperature range that does not adversely affect the operation of the pulse gas valve 8 and the gas introduction pipe 10 does not adversely affect the operation of the pulse gas valve 8, and when there are other components used around the valve, such as an O-ring. The upper limit is a temperature that does not affect them. The inner wall of the processing chamber 1 is desirably heated to a high temperature, and is controlled to the same temperature as the inner wall of the plasma chamber 2. The sample 7 can be expected to improve the processing speed by lowering the temperature. As an example of a specific temperature setting, the partition plate 3, the pulse gas valve 8, and the gas introduction pipe 10 are set to the highest temperature, for example, 120 ° C.
It is preferable that the inner wall of the plasma chamber 2 and the inner wall of the processing chamber 1 are controlled to be lower than that, for example, about 100 ° C., and the stage 6 (sample 7) is further lower, for example, about 0 ° C.

It should be noted that all of the partition plate 3, the pulse gas valve 8 and the gas introduction pipe 10 do not need to be kept at a higher temperature than the inner wall of the plasma chamber 2, and at least one of them may be kept at a higher temperature. Needless to say.

Embodiment 2 FIG. In Embodiment 1, when an insulator is used as the partition plate 3, the partition plate 2 may be heated by a configuration as shown in FIG. In the figure, reference numerals 101 and 103 denote electrically insulating partition members, each having a hole (not shown) as in the first embodiment. Reference numeral 102 denotes a heat-generating electric resistor, which is provided with a hole (not shown) at the same position as the partition members 101 and 103, is disposed in close contact between the partition members 101 and 103, and is insulated from the outer wall of the apparatus. . Exothermic electrical resistor 102
By supplying independent electric power that does not impair the vacuum state and does not affect any part in the apparatus such as the inner wall of the plasma chamber 2, the partition member is heated by the heat generated from the heat-generating electric resistor 102. Heating of 101 and 103 can be performed. Further, the temperature can be controlled by controlling the power supplied to the heat-generating electric resistor 102. With such a configuration, uniform heating of the partition plate 3 can be relatively easily performed.

Embodiment 3 In the above embodiment, the partition wall 3, the pulse gas valve 8, and the gas inlet tube 10 are heated to maintain the inner wall of the plasma chamber 2 at a higher temperature, but the inner wall of the plasma chamber 2 is heated to a higher temperature by the plasma. If the upper limits of the partition plate 3, the pulse gas valve 8 and the gas introduction pipe 10 are exceeded, the inner wall of the plasma chamber 2 may be cooled by a cooling means such as cooling water.

Embodiment 4 FIG. 3 is a sectional view schematically showing a plasma etching apparatus according to a fourth embodiment of the present invention. The dry etching apparatus according to the present embodiment has the same configuration as that of the first embodiment, but does not include the waveguide 11 for guiding microwaves, the microwave introduction window 12 and the magnetic field coil 13, and the RF power applying means 270 is not provided. The provided dry etching apparatus. In the figure, the RF power applying means 270 includes a plasma RF power source 277 for applying RF power to the RF coil 272,
Are arranged around the side wall 271. The RF coil 272 includes a conductor 273 and a first insulator 27 covering the conductor 273.
4 and the periphery of the RF coil 272 is further covered with a conductive material 275 of a metal thin film, and the periphery is covered with a second insulator 276.

In the device configured as described above,
By providing heating means such as heater wires 14 and 15 to the pulse gas valve 8, the gas introduction pipe 10 and the partition plate 3, and providing means for cooling the plasma chamber 2, the pulse gas valve 8, the gas introduction pipe 10 and the partition plate are provided. 3 is maintained at a higher temperature than the plasma chamber 2, the partition plate 3, the pulse gas valve 8, and the gas introduction pipe 1, as in the first to third embodiments.
The adhesion of the polymer film to the substrate can be suppressed, and a stable pulse gas supply and a stable etching process can be obtained. Further, since the adhesion of the polymer film to the partition plate 3 and the like can be suppressed, the contamination of the processing chamber 1 due to dust generated by peeling of the polymer film or the like can be reduced.

In the above-described first to fourth embodiments, the plasma generator of the ICP type or the ECR type has been described as a type of generating plasma, but the present invention is not necessarily limited to this type. Similar effects can be obtained by using a plasma generator of an inductive coupling type, a magnetron type, a parallel plate type or the like.

Therefore, it should be understood that the embodiments disclosed this time are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[0032]

As described above, according to the present invention, a plasma chamber in which a plasma is generated by an excitation source using a gas, a processing chamber in which a sample is arranged, the plasma chamber and the processing chamber And a partition plate having a hole communicating from the plasma chamber to the processing chamber, vacuum evacuation means for exhausting the processing chamber, and gas supply means for supplying the gas in a pulsed manner to the plasma chamber. Since the plasma processing apparatus includes means for maintaining at least one of the partition plate and the gas supply means at a temperature higher than the inner wall of the plasma chamber, foreign matter such as a polymer film adheres to the partition plate or the gas supply means. Deposition can be prevented, and a stable supply of pulse gas and a stable etching process can be obtained. Further, generation of dust due to peeling of the deposited polymer film can be suppressed.

In addition, at least one of the means for heating at least one of the partition plate and the gas supply means and the means for cooling the inner wall of the plasma chamber makes at least one of the partition plate and the gas supply means a plasma chamber. It can be maintained at a higher temperature in an optimal temperature range than the inner wall.

[Brief description of the drawings]

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

FIG. 2 is a side view showing a configuration of a main part of a plasma dry etching apparatus according to a second embodiment of the present invention.

FIG. 3 is a sectional configuration view schematically showing a plasma dry etching apparatus according to a fourth embodiment of the present invention.

FIG. 4 is a schematic configuration diagram showing a dry etching apparatus of a conventional plasma processing apparatus.

FIG. 5 is a schematic configuration diagram showing a dry etching apparatus of another conventional plasma processing apparatus.

[Explanation of symbols]

1 processing chamber, 2 plasma chamber, 3 partition plate, 4 holes, 5
Exhaust port, 6 stage, 7 sample, 8 pulse gas valve, 9 driving device, 10 gas introduction pipe, 11 waveguide,
12 Microwave introduction window, 13 Magnetic field coil, 14, 1
5 heater wire, 101, 103 electrically insulating partition member, 102 heat-generating electric resistor, 270 RF power applying means, 272 RF coil, 277 plasma RF power supply.

────────────────────────────────────────────────── ─── Continued on front page (51) Int.Cl. ⁶ Identification symbol FI H01L 21/31 H01L 21/302 B (72) Inventor Kazuyasu Nishikawa 2-3-2 Marunouchi 2-chome, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation In-house (72) Inventor Hiroki Odera 2-3-2 Marunouchi, Chiyoda-ku, Tokyo, Japan Mitsubishi Electric Corporation (72) Inventor Tatsuo Omori 2-3-2 Marunouchi, Chiyoda-ku, Tokyo, Mitsubishi Electric Corporation

Claims (3)

[Claims] 1. A plasma chamber in which a plasma is generated by an excitation source using a gas, a processing chamber in which a sample is arranged,
A partition plate provided between the plasma chamber and the processing chamber and having a hole communicating with the processing chamber from the plasma chamber; a vacuum exhaust unit for exhausting the processing chamber; A plasma processing apparatus comprising: a gas supply means for supplying a gas; and a means for maintaining at least one of the partition plate and the gas supply means at a temperature higher than the inner wall of the plasma chamber. 2. The plasma processing apparatus according to claim 1, further comprising means for heating at least one of the partition plate and the gas supply means. 3. The plasma processing apparatus according to claim 1, further comprising means for cooling said plasma chamber.