JP2001140085A - Plasma treating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma treating system capable of reducing the number of matching circuit nets and high frequency exiting power sources to be used as small as possible while maintaining the characteristic functions of the device regardless of the number of high frequency electrodes provided in a vacuum chamber. SOLUTION: Each of plural respective electrodes provided in a vacuum chamber is connected with a vacuum capacitor or an LC circuit and is connected to a common high frequency power source via a common matching circuit net.

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, in which A is a vacuum chamber in which a plurality of substrate electrodes B are arranged in pairs with respective counter electrodes C. Each substrate electrode B is a matching network D
Are connected to the respective high-frequency excitation power supplies E. 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 circuits and high-frequency excitation power supplies by the number of substrate electrodes provided in the vacuum chamber. is there. Therefore, as the number of high-frequency electrodes provided increases, the number of matching circuits 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.

[0004] In order to reduce the cost of the apparatus,
It is conceivable to connect a plurality of high-frequency electrodes provided in a vacuum chamber to a common matching network and a high-frequency excitation power supply.However, in such a configuration, a connection plate (normally, Dispersion of the inductance of copper (copper) causes discharge to concentrate on the electrode having the lowest impedance, resulting in non-uniform power distribution, making it difficult to generate stable plasma, which is an advantage of high-frequency excitation.

In order to solve the problems of the prior art, the present invention provides a matching network and a matching network used while maintaining the original function of the apparatus, regardless of the number of high-frequency electrodes provided in the vacuum chamber. It is an object of the present invention to provide a plasma processing apparatus capable of reducing the number of high-frequency excitation power supplies as much as possible.

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 predetermined processing by utilizing, a plurality of high-frequency electrodes provided in a vacuum chamber are connected to a common power supply via a vacuum capacitor and a common matching network, respectively. I have.

Further, 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 a predetermined processing is performed by utilizing plasma generated in the vacuum chamber. Is characterized in that a plurality of high-frequency electrodes provided in a vacuum chamber are connected to a common power supply via an LC circuit and a common matching network.

In the present invention, the vacuum capacitor or the LC circuit connected to each high-frequency electrode corrects variations in capacitance of the high-frequency electrode and variations in inductance of the connection base to which the high-frequency electrode is attached, which may occur in manufacturing the device. Thus, it functions so that high-frequency power is uniformly distributed to each high-frequency electrode.

When the number of high-frequency electrodes provided in the vacuum chamber is relatively large, the high-frequency electrodes are divided into a plurality of groups each including a plurality of high-frequency electrodes. It can be connected to a common high frequency power supply via a capacitor or LC circuit and a common matching network. Also, preferably, the vacuum condenser connected to each high-frequency electrode may be composed of a variable vacuum condenser.

[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. Each of the high-frequency electrodes 2 is connected to a common matching network 5 and a common high-frequency power source 6 via a variable vacuum capacitor 4.

In the illustrated embodiment, the number of high-frequency electrodes 2 is merely for illustrative purposes, and may be two, three, four or more. Each vacuum condenser 4 may be a fixed type instead of a variable type.

In the illustrated embodiment, the electrode capacity of the high-frequency electrode 2 is Ci (i = 1 to 4), the capacity of the variable vacuum capacitor 4 is Ci '(i = 1 to 4), and the high-frequency electrode 2 is mounted. Assuming that the inductance of the copper connection base (not shown) is Li (i = 1 to 4), the impedance Zi (i = 1 to
4) is represented by Zi = jωLi + 1 / (Ci + Ci ′). Here, the capacitance Ci ′ (i = 1 to 4) of the variable vacuum capacitor 4 is set so that Z1 = Z2 = Z3 = Z4. As a result, high-frequency power is distributed uniformly over the entire high-frequency electrode 2.

Next, an experimental example in which SiO ₂ substrates a, b, c and d are etched using the illustrated apparatus will be described. As operating conditions of the apparatus, CF ₄ and O ₂ were flowed into the vacuum chamber at 800 SCCM and 200 SCCM, respectively, for a total of 1000 SCCM, and the pressure was increased
10 Pa, the distance between the substrate and the counter electrode 3 was 110 mm, the applied high frequency power was 2.0 kW, and the condition I was 2.0 kW, and the vacuum chamber pressure was 7 Pa, and the other conditions were the same as the condition I. When the etching rate (angstrom / min) of each substrate was measured, the following results were obtained. The distance between the substrate and the counter electrode 3 is determined by the gas, pressure, and discharge frequency. Substrate In case of condition I Average value of 5 points in electrode in case of condition II Average value of 5 points in electrode a 661 ± 8.2 643 ± 3.1 b 652 ± 7.1 654 ± 4.1 c 668 ± 8.6 638 ± 2.5 d 659 ± 6.3 648 ± 1.8

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, high-frequency electrodes 2 are provided symmetrically on the lower wall of the rectangular vacuum chamber 1 and on the upper wall opposed thereto, respectively. In the vacuum chamber 1, a common anode electrode 3 is arranged along an intermediate position between the upper and lower high-frequency electrodes 2, that is, along a longitudinal central axis of the vacuum chamber 1. The anode electrode 3 is grounded as in the embodiment shown in FIG. The upper and lower high-frequency electrodes 2 are paired two by two and connected to a common matching circuit network 5 and a common high-frequency power source 6 via respective variable vacuum capacitors 4. Therefore, four high-frequency power supplies 6 that are half of the eight high-frequency electrodes 2 are used.

As shown in the figure, between the both sides of each high-frequency electrode 2 and the central anode electrode 3, partition members 7 having a ground potential made of a punching metal or mesh metal having a hole diameter of 3 mm or less are provided. I have. These partition members 7 function to confine the discharge plasma generated in the space defined between each high-frequency electrode 2 and the central anode electrode 3, and suppress high-frequency interference between adjacent high-frequency electrodes 2. .

FIG. 3 is an enlarged view showing the details of the configuration of one high-frequency electrode 2 and one anode electrode 3 in the apparatus shown in FIG. The high-frequency electrode 2 is vacuum-sealed to an opening provided in the wall of the vacuum chamber 1 via an insulating member 8 made of, for example, Teflon (registered trademark) or alumina. The high-frequency electrode 2 has a water cooling channel 9 inside. A pedestal 10 made of aluminum is fixed on a surface of the high-frequency electrode 2, that is, a surface facing the anode electrode 3 by fixing means 11, and an electrostatic chucking electrode 12 is provided thereon. A substrate to be formed, for example, a film-like substrate (not shown) is mounted by a clamp 13 made of alumina. In general, the attraction force of the electrostatic attraction electrode 12 depends on the surface shape of the substrate to be processed, and the substrate to be used is limited in the conductor to be attracted. 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 12 is etched by the plasma, so that the life is shortened. In order to solve these problems, the clamp 13 made of alumina may be configured to cover the peripheral edge of the substrate as shown in the figure, and may be configured to absorb thermal expansion. Further, a DC power supply (not shown) is connected to the electrostatic chucking electrode 12 via a lead wire 14, and this DC power supply can preferably be provided commonly to all or some of the electrostatic chucking electrodes 12. .

The central anode electrode 3 has a water cooling channel 15 provided therein. An etching gas supply gas pipe 16 is provided near the center anode electrode 3 in the space between the anode electrode 3 and each high-frequency electrode 2. 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 7 provided on both sides of each high-frequency electrode 2 and defining a plasma region are set to the ground potential as described above in order to minimize the potential induced by the high-frequency plasma. The partitioning member 7 is preferably made of a mesh or punching metal having a diameter of 3 mm or less for each hole in order to facilitate the movement of the gas, that is, the introduction and exhaust of the gas, in order to facilitate the gas introduction and exhaust, and to suppress the plasma leakage. Is done.

In the embodiment shown in FIGS. 2 and 3, one high-frequency power source 6 is connected to two high-frequency electrodes 2.
However, if necessary, three or more high-frequency electrodes 2 can be connected to one high-frequency power supply. Although the illustrated apparatus is implemented as a batch-type apparatus, the apparatus can be implemented as a load-lock-type apparatus. Further, in the present invention, as described above, the same operation and effect can be obtained by using an LC circuit instead of the vacuum capacitor.

As described above, in the plasma processing apparatus according to the present invention, a vacuum capacitor or an LC circuit is connected to each of a plurality of high-frequency electrodes provided in a vacuum chamber, and is connected via a common matching network. Since it is configured to be connected to a common high-frequency power supply, high-frequency power can be uniformly distributed to all high-frequency electrodes, and the number of power supplies and matching networks is significantly reduced (actually less than half). Will be able to As a result, not only can the cost of the apparatus be significantly reduced, but also the weight of the apparatus can be reduced, and further, an effect such as securing a sufficient space for maintenance can be obtained.

[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: vacuum capacitor 5: common matching network 6: common high-frequency power supply

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05H 1/46 H01L 21/302 C (72) Inventor Kafumi Ota 523 Yokota, Sanmu-cho, Sanmu-gun, Chiba Nihon Vacuum (72) Inventor Masashi Kikuchi 2500 Hagizono, Chigasaki-shi, Kanagawa Japan Vacuum Engineering Co., Ltd. (72) Inventor Hitoshi Ikeda 2500 Hagizono, Chigasaki-shi, Kanagawa Japan Vacuum Engineering Co., Ltd. 72) Inventor Masaru Ozono 2500 Hagizono, Chigasaki-shi, Kanagawa Japan F-term (reference) 4K030 FA03 KA14 4K057 DA20 DB11 DD01 DE06 DE08 DE14 DE20 DM02 DM40 5F004 AA16 BA06 BB13 BD04 CA02 CA03 DA01 DA25 DA26 5F045 AA08 AC11 AC15 BB08 EH04 EH06 EH13

Claims (5)

[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. A plasma processing apparatus, wherein a plurality of high-frequency electrodes provided in a vacuum chamber are connected to a common high-frequency power supply via respective vacuum capacitors and a common matching network. 2. A plurality of high-frequency electrodes provided in a vacuum chamber are divided into a plurality of groups, and the plurality of high-frequency electrodes in each group are connected to a common high-frequency power supply via respective vacuum capacitors and a common matching network. The plasma processing apparatus according to claim 1, wherein: 3. The vacuum capacitor connected to each high-frequency electrode is a variable vacuum capacitor.
Or the plasma processing apparatus according to 2. 4. 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. A plasma processing apparatus, wherein a plurality of high-frequency electrodes provided in a vacuum chamber are connected to a common high-frequency power supply via respective LC circuits and a common matching network. 5. A plurality of high-frequency electrodes provided in a vacuum chamber are divided into a plurality of groups, and the plurality of high-frequency electrodes in each group are connected to a common high-frequency power supply via respective LC circuits and a common matching network. The plasma processing apparatus according to claim 4, wherein: