JP2001077091A - Plasma processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid a high-frequency interference which occurs between adjacent high-frequency electrodes so as to prevent a hunting phenomenon by a method wherein partitioning members which demarcate plasma generating spaces respectively are provided inside a vacuum chamber. SOLUTION: A partitioning member 6 of meshes or punching metal is provided between adjacent high-frequency electrodes 2 and at an outward edge of electrodes 2 located at the ends of a row of electrodes 2. The partitioning members 6 demarcates a plasma generating space between the high-frequency electrode 2 and an anode electrode 3. The partitioning members 6 are connected to a ground potential so as to reduce a potential induced by high-frequency plasma to an irreducible minimum. By this setup, the partitioning members are permeable to gas but substantially restrain plasma, which is generated in the plasma generating spaces demarcated by them combined with the high-frequency electrodes 2, from leaking out, and a high-frequency interference between the adjacent high-frequency electrodes 2 can be avoided, so that a hunting phenomenon can be prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a plurality of electrodes in one vacuum chamber, mounts a substrate to be processed on each electrode, and performs etching, for example, by using plasma generated in the vacuum chamber. The present invention relates to a plasma processing apparatus that performs a predetermined process such as sputtering or chemical vapor deposition (chemical vapor deposition).

[0002]

2. Description of the Related Art In recent years, various apparatuses using plasma for forming thin films, functional films, and patterns in semiconductors and electronic parts have been used. FIG. 4 of the accompanying drawings shows a conventional example of this type of apparatus, where A is a vacuum chamber provided with an exhaust system, and a substrate electrode B is provided in each vacuum chamber A.
Are arranged in pairs with the respective counter electrodes C.
Each substrate electrode B is connected to a respective high-frequency excitation power source E via a matching network D. Each counter electrode C is grounded as shown.

[0003]

Although such a conventional apparatus is satisfactory from the viewpoint of productivity, it is necessary to provide matching networks and high-frequency excitation power supplies by the number of substrate electrodes. Therefore, as the number of high-frequency electrodes provided increases, the number of matching circuit networks and high-frequency excitation power supplies used increases, and the cost of the apparatus increases accordingly. As described above, this type of conventional apparatus has a high facility cost and is required to be reduced in cost.

In order to reduce the cost of the apparatus, there has been proposed an apparatus in which a plurality of high-frequency electrodes provided in a vacuum chamber are connected to a common matching network and a high-frequency excitation power supply. However, in such a configuration,
Discharge concentrates on the electrode with the lowest impedance due to variations in the inductance of each electrode capacity and the connection plate (usually made of copper) on which the electrode is mounted, and the power distribution becomes uneven, which is an advantage of high frequency excitation. It is difficult to generate stable plasma. That is, since adjacent high-frequency electrodes share a plasma space and a plurality of high-frequency powers are supplied to a plurality of input sources, in a configuration in which a plurality of high-frequency electrodes are excited by one system of high-frequency power, one system is used. The matching network and the control system cannot perform appropriate control, and hunting and a state in which application of high-frequency power cannot be continued may occur. Under such circumstances, parallel processing of the substrates mounted on the respective high-frequency electrodes has not been actually performed except for, for example, cleaning during sputtering or chemical vapor deposition. Further, in the case of a relatively small device with a relatively small input power, the mutual interference in the plasma space between adjacent high-frequency electrodes can be suppressed without being so large, but in a device with a large and high power input, the interference in the plasma space can be reduced. Mutual interference can no longer be greatly suppressed, which hinders the realization of a large-sized device that inputs a large amount of power.

[0005] In order to solve the problems of the prior art, a plasma space for each high-frequency electrode provided in a vacuum chamber is defined while maintaining the original function of the apparatus, and the parallel processing of substrates is performed. It is an object of the present invention to provide a plasma processing apparatus that enables the above.

In order to achieve the above object, according to the present invention, a substrate to be processed is mounted on each of a plurality of high-frequency electrodes provided in one vacuum chamber, and plasma generated in the vacuum chamber is supplied. In a plasma processing apparatus configured to perform a predetermined process using a plasma processing apparatus, a partition member that defines a plasma generation space of each of a plurality of high-frequency electrodes provided in a vacuum chamber is provided, and each partition member allows a gas to pass therethrough. It is characterized in that it is configured to substantially suppress leakage of plasma generated in each plasma generation space combined with each high-frequency electrode.

In the present invention, each partition member is preferably connected to a ground potential so as to minimize the potential induced by the high frequency plasma.

Each partition member has an aperture ratio of 70 to 20%,
Preferably, it may be made of a mesh or punched metal having an opening ratio of 45 to 25% and a diameter of each opening of 3 mm or less.

In the apparatus according to the present invention, the plasma generated by each of the high-frequency electrodes is effectively confined in the plasma generation space defined by the partition member, and the gas necessary for the plasma processing is removed. The introduction and exhaust functions are also maintained. Further, by setting the diameter of each opening in a mesh or a punching metal that can be used as a partition member to 3 mm or less, high-frequency interference between adjacent high-frequency electrodes can be avoided, and the occurrence of a hunting phenomenon can be suppressed. According to the present invention having such a configuration, high-frequency interference between adjacent high-frequency electrodes can be avoided, so that a large-sized device for supplying large power can be provided.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 schematically shows one embodiment in which the present invention is implemented as a plasma etching apparatus. Reference numeral 1 denotes a vacuum chamber connected to an exhaust system and a discharge gas (not shown), and a lower wall of the vacuum chamber 1 is provided with four substrate electrodes, that is, a high-frequency electrode 2 constituting a cathode electrode. A common anode electrode 3 is provided along the upper side wall of the vacuum chamber 1 so as to face the high-frequency electrode 2, and the counter electrode 3 is grounded. Two adjacent high-frequency electrodes 2 are connected to a common high-frequency power supply 5 via a common matching network 4.

Further, between adjacent high-frequency electrodes 2 and at outer ends of the high-frequency electrodes 2 at both ends, partition members 6 made of mesh or punched metal are provided, and each partition member 6 is connected to the high-frequency electrode 2 side and the anode electrode. Extends between 3 and defines the plasma generation space. Each partition member 6 is connected to the ground potential to minimize the potential induced by the high-frequency plasma, and the mesh or the punching metal constituting each partition member 6 includes a gas of each high-frequency electrode 2. In order to facilitate movement, that is, gas introduction and exhaust, and to suppress plasma leakage, an aperture ratio of 70
-20%, preferably 45-25%, and each hole has a diameter of 3 mm or less. Here, regarding the aperture ratio, if the aperture ratio is large, the interference of the discharge cannot be ignored, and if it is too small, the gas cannot be exhausted, the reaction speed of etching or the like becomes slow, or the dispersion of the distribution becomes large. A range is preferred. In the illustrated embodiment,
The number of high-frequency electrodes 2 is merely for illustrative purposes, and may be two, three, or four or more.

FIGS. 2 and 3 show another embodiment of the present invention in which a large number of cathode electrodes are provided on both sides of an anode electrode. That is, as shown, four cathode electrodes, that is, four high-frequency electrodes 11 are provided symmetrically on the lower wall of the rectangular vacuum chamber 10 and on the upper wall facing the same, respectively. In the vacuum chamber 10, a common anode electrode 12 is arranged along an intermediate position between the upper and lower high-frequency electrodes 11, that is, a longitudinal central axis position of the vacuum chamber 1. The anode electrode 12 is connected to the ground as in the embodiment shown in FIG. The upper and lower high-frequency electrodes 11 are connected to a common matching circuit network and a high-frequency power supply 13 in pairs. Therefore, four high-frequency power supplies 13 that are half of the eight high-frequency electrodes 11 are used.

As shown in the figure, between each side of each of the high-frequency electrodes 11 and the central anode electrode 12, there is provided a partition member 14 made of a punching metal or mesh metal having a hole diameter of 3 mm or less and connected to a ground potential. Is provided. These partition members 14 are, like the partition member 6 in FIG. 1, each of the high-frequency electrodes 11 and the central anode electrode 12.
And confine the discharge plasma generated in the space defined between them, and suppress high-frequency interference between adjacent high-frequency electrodes 11.

FIG. 3 is an enlarged view showing details of the configuration of one high-frequency electrode 11 and one anode electrode 12 in the apparatus shown in FIG. The high-frequency electrode 11 has an opening provided in the wall of the vacuum chamber 10 in an insulating member 15 made of, for example, Teflon or alumina.
And is mounted in a vacuum-tight manner through. The high-frequency electrode 11 has a water cooling channel 16 inside. High frequency electrode
A pedestal 17 made of aluminum is fixed on the surface of 11, that is, the surface facing the anode electrode 12, by fixing means 18,
An electrostatic attraction electrode 19 is provided thereon, and this electrostatic attraction electrode
A substrate to be processed, for example, a film-like substrate (not shown) is mounted on the substrate 19 by a clamp 20 made of alumina. In general, the attraction force of the electrostatic attraction electrode 19 depends on the surface shape of the substrate to be processed, and as a substrate to be used, there are restrictions on conductors to be attracted and, moreover, at the surface where a resist mask is used for pattern formation. Because there are irregularities, it cannot be strengthened. Also, it is strong in the conductor pattern of the substrate and weak in other portions. Further, the thermal expansion of the substrate differs depending on the material. The thermal expansion is large in the conductor pattern of the substrate, and swelling is likely to occur during the plasma processing. When this wrinkling occurs on the end surface of the substrate, abnormal discharge occurs at the end of the substrate. Further, the surface material of the electrostatic attraction electrode 19 is etched by the plasma, so that the life is shortened. Therefore, the clamp 20 made of alumina is configured to cover the peripheral edge of the substrate as illustrated. Further, a DC power supply (not shown) is connected to the electrostatic attraction electrode 19 via a lead wire 21.
This DC power supply can preferably be provided in common for all or some of the electrostatic chucking electrodes 19.

The central anode electrode 12 has a water cooling channel 22 provided therein. An etching gas supply gas pipe 23 is provided near the center anode electrode 12 in the space between the anode electrode 12 and each high-frequency electrode 11. As the etching gas, a mixed gas of a halogen gas containing fluorine and O ₂ or N ₂ , or a mixed gas of this mixed gas and a gas containing CH such as CHF ₃ can be used.

The partition members 14 provided on both sides of each high-frequency electrode 2 for limiting the plasma region are set to the ground potential as described above in order to minimize the potential induced by the high-frequency plasma. In order to facilitate the movement of each gas, that is, the introduction and exhaust of gas, a partition member
14 is preferably an aperture ratio as in the embodiment of FIG.
It is composed of a mesh or punched metal with a diameter of 3 mm or less for each hole to suppress plasma leakage at about 45 to 25%.

In the embodiment shown in FIGS. 2 and 3, one high-frequency power source 13 is connected to two high-frequency electrodes 11.
Is used, but if necessary, three or more high-frequency electrodes
11 may be connected to one high-frequency power supply. Also, the illustrated apparatus is implemented as a batch type apparatus, but can be applied as another type of apparatus.

Next, a polyimide film a,
Experimental examples in which b, c, d, e, f, g, and h are etched will be described. The operating conditions of the device are as follows: the distance between the high-frequency electrode and the anode electrode (which is determined by the gas, pressure and discharge frequency) is 110 mm, and CF4 and O2 are 200 SCCM and 2000 SCCM, respectively, in a vacuum chamber.
Sink; When the pressure in the vacuum chamber is 30 Pa, the input high frequency power is 2.5 kW, and the etching time is 20 minutes,
II. When the average etching depth (μm) of each substrate was measured when the pressure in the vacuum chamber was 12 Pa, the applied high frequency power was 2.0 kW, and the etching time was 20 minutes, the following results were obtained. In the case of condition II In the case of condition II a 7.1 5.3 b 7.4 5.5 c 7.6 5.4 d 7.0 5.0 e 6.8 4.9 f 6.9 5.0 g 7 .1 5.3 h 7.8 4.8

[0019]

As described above, in the plasma processing apparatus according to the present invention, the partition members for defining the plasma generation space of each of the plurality of high-frequency electrodes provided in the vacuum chamber are provided, and each partition member is Since it is configured to allow gas to pass therethrough but to substantially suppress leakage of plasma generated in each plasma generation space combined with each high-frequency electrode, it is possible to limit the plasma region by each high-frequency electrode, Thereby, high-frequency interference between adjacent high-frequency electrodes can be avoided, hunting phenomenon and the like can be prevented, and parallel processing of substrates can be performed to improve productivity.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a plasma processing apparatus according to one embodiment of the present invention.

FIG. 2 is a schematic diagram showing a plasma processing apparatus according to another embodiment of the present invention.

FIG. 3 is an enlarged vertical sectional view showing a detailed structure of the plasma processing apparatus shown in FIG. 2;

FIG. 4 is a schematic diagram illustrating an example of a conventional plasma processing apparatus.

[Explanation of symbols]

 1: vacuum chamber 2: high-frequency electrode 3: anode electrode (counter electrode) 4: common matching circuit network 5: common high-frequency power supply 6: partition member

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kafumi Ota 523 Yokota, Sanmu-cho, Yamatake-gun, Chiba Pref. Japan Vacuum Engineering Co., Ltd. Within Technology Co., Ltd. (72) Inventor Hitoshi Ikeda 2500 Hagizono, Chigasaki-shi, Kanagawa Japan Nippon Vacuum Technology Co., Ltd. FA03 GA02 KA08 KA12 4K057 DA20 DD01 DE01 DE06 DE11 DE20 DM03 DM06 DM28 DM33 DM35 DM39 DN01 DN02 5F004 AA16 BA06 BA09 BB11 BB18 BB21 BB22 BB23 BB25 BB29 DA00 DA04 DA16 DA25 DA26 DB25 5F045 AA10 DP03E13D03E03D13E03D13E

Claims (4)

[Claims] 1. A plasma in which a substrate to be processed is mounted on each of a plurality of high-frequency electrodes provided in one vacuum chamber, and a predetermined process is performed using plasma generated in the vacuum chamber. In the processing apparatus, a partition member that defines a plasma generation space of each of the plurality of high-frequency electrodes provided in the vacuum chamber is provided, and each partition member allows a gas to pass therethrough, but in each plasma generation space combined with each high-frequency electrode. A plasma processing apparatus configured to substantially suppress leakage of generated plasma. 2. The plasma processing apparatus according to claim 1, wherein each partition member is connected to a ground potential so as to minimize a potential induced by the high-frequency plasma. 3. The plasma processing apparatus according to claim 1, wherein each partition member is made of a mesh or punched metal having an opening ratio of 70 to 20% and a diameter of each opening of 3 mm or less. 4. The plasma processing apparatus according to claim 1, wherein each partition member is made of a mesh or punched metal having an opening ratio of 45 to 25% and a diameter of each opening of 3 mm or less.