JPH02303029A - Plasma electrode - Google Patents

Abstract

PURPOSE:To improve the uniformity of a film thickness in a batch by a method wherein dummy substrates for impedance correction use are provided and the impedances between electrode plates are corrected so as to become uniform over the whole region of each electrode plate. CONSTITUTION:If there is a gap between substrates 4 and electrode plates 2, different contact resistances and different capacitances are generated according to the flatnesses of the plates 2 and the degree of roughness of the surfaces of the plates 2. Moreover, by the plates 2, variation is generated in the impedances between the upper and lower electrode plates over the whole region of each electrode plate. There, the resistance and capacitance of each dummy electrode 6 are matched to the variation of the impedance of each plate 2 and the impedances between the upper and lower electrode plates can be uniformly matched to each other properly over the whole region of each electrode plate. Thereby, plasma power is uniformly distributed between the plates 2 and a film having a good uniformity can be deposited on each substrate 4. Moreover, the substrates 4 are respectively mounted to the lower part of each plate 2 by fixing jigs 5 and the above effect is fulfilled.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is used for plasma reactions in plasma CVD apparatuses and the like that require film growth with good film thickness uniformity. It relates to plasma electrodes.

(Prior Art) In recent years, a vertical plasma CVD device capable of large-scale batch processing has been developed and put into practical use, and a vertical multilayer parallel plate plasma electrode is used as the electrode thereof.

An example of a conventional plasma and electrode configuration will be described below with reference to FIG.

In FIG. 3, 1 is a high-frequency power source for generating plasma, 2 is an electrode plate arranged vertically facing each other, and 3 is a high-frequency power source for generating plasma.
is a rod-shaped lead W1 pole, which is connected to every other electrode plate 2. 4 is a substrate on which a film is deposited, and electrode plate 2
Plasma is generated between the opposing electrode plates placed on the top surface of the J! [Prices are now deposited on top of 4.

Figure 4 shows an equivalent circuit between a pair of opposing electrode plates when a substrate is placed on the electrode plate and a plasma reaction is occurring. In Figure 4, 11 is the upper electrode plate, 12 is the lower electrode plate. The capacitance and resistance components between them will be explained below.

16 is a space capacitance, which is the capacitance from the upper surface of the substrate to the upper electrode plate. 14 is a substrate resistance. Reference numeral 13 denotes contact resistance, which occurs between the substrate and the lower electrode plate.

15 is a capacitance, which is caused by a gap caused by the fact that the electrode plate and the substrate are not perfectly flat.

Since the flatness of one surface of each of the many electrode plates is not the same, the contact resistance 13 and capacitance 15 are different and vary for each of the many electrode plates.

Therefore, the impedance generated between the upper electrode plate 11 and the lower electrode plate 12 is no longer the same over the entire electrode area, and plasma power is not evenly distributed between each electrode plate. A problem arises in that the thickness of the film deposited on the substrate is always thicker or thinner than average, resulting in poor uniformity of film thickness within the same batch.

(Problems to be Solved by the Invention) As described above, the conventional vertical multilayer parallel plate plasma electrode has a problem in that the uniformity of the film thickness within the same batch is poor when depositing a film.

The present invention solves the above-mentioned conventional problems, and is a plasma electrode whose purpose is to improve the uniformity of film thickness within the same batch.

(Means for Solving the Problem) In order to achieve this object, the plasma electrode of the present invention has a fixing jig that can attach a substrate to the lower surface of each electrode plate.

(Function) According to this structure, a dummy substrate for impedance correction is attached to the lower part of the electrode plate using a fixing jig, and the impedance between opposing electrode plates is corrected to be uniform over the entire electrode area.

The resistance, capacitance, and material of the dummy substrate can be appropriately selected, and when depositing a film, the difference in impedance between the electrode plates causes the plasma power to differ between each electrode plate, resulting in film thickness variations within the same batch. Uniformity can be improved.

(Example) An example of the present invention will be described below with reference to one drawing.

FIG. 1 shows the structure of a plasma electrode in an embodiment of the present invention. In Figure 1, 1 is a high frequency power supply;
2 is an electrode plate, and 3 is a rod-shaped lead electrode, which is connected to every other electrode plate 2.

4 is a substrate on which a film is deposited. A fixing jig 5 is made of ceramic and is used to place the substrate on the lower surface of the electrode plate 2. Reference numeral 6 denotes a dummy substrate for impedance correction, which is attached to the lower surface of each electrode plate using a fixing jig 5.

Figure 2 shows an equivalent circuit between a pair of opposing electrode plates of the plasma electrode configured as described above. The resulting resistance component and capacitance component will be explained below. In FIG. 2, 16 is a space capacitance between opposing substrate surfaces, 14 is a substrate resistance, and 13 is a contact resistance, which occurs between the substrate and the electrode plate. No. 15 is 8%, which is caused by a gap caused by the electrode plate and the substrate not being in complete contact with each other. Here, since the contact resistance 13 and capacitance 15 differ depending on each electrode plate depending on the flatness of the electrode plate and the degree of surface unevenness, the impedance between the upper electrode plate 11 and the lower electrode plate 12 will vary over the entire electrode area. By appropriately selecting the resistance and capacitance of the dummy substrate 6 according to the variations in each electrode plate,
Upper type horizontal plate 11-lower iT! It is possible to make the impedance between the electrode plates 12 uniform, the plasma power is evenly distributed between each electrode plate, and a highly uniform film can be deposited on the substrate 4 placed on the electrode plate. can. In order to change the capacitance and resistance of the dummy substrate 6, an oxide film of 100 to 3000 layers is coated on the back side of the substrate with different resistivity, and a different C.
It can be deposited on a VD system.

As described above, according to this embodiment, by attaching a dummy substrate for impedance correction to the lower part of the electrode plate using a fixing jig, a film with good film thickness uniformity is deposited on the substrate placed above the electrode plate. It is now possible to do so.

In this embodiment, 6 is a dummy substrate, but if film thickness uniformity is not an issue, it may be used as a substrate on which a film is deposited.

Further, in this embodiment, the plasma electrode was used in a CvD apparatus for depositing a film, but it goes without saying that it may also be used in an etching apparatus.

(Effects of the Invention) As described above, the present invention has a structure that allows the substrate to be attached to the lower surface of the electrode plate using a fixing jig, thereby forming a film with good film thickness uniformity on the substrate. It is possible to realize an excellent plasma electrode that can be deposited,
Moreover, compared to the case where the substrate is attached only to the upper surface of the electrode plate, it becomes possible to attach the reacted substrate to both the upper and lower surfaces, and the amount of substrates that can be processed at one time can be doubled.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a plasma electrode in an embodiment of the present invention, Fig. 2 is an equivalent circuit diagram between opposing electrode plates of a plasma electrode in an embodiment of the present invention, and Fig. 3 is an implantation diagram of a conventional plasma electrode. , FIG. 4 is an equivalent circuit diagram between opposing electrode plates of a conventional plasma electrode. 1...High frequency power supply, 2...Electrode plate, 3...
Lead electrode, 4... Board, 5... Fixing jig, 6
...Dummy board, 11... Upper m-electrode plate, 12...
- Lower electrode plate, 13... Contact resistance, 14... Substrate resistance, 15... Capacitance, 16... Space capacitance. Patent applicant Matsushita Electronics Co., Ltd. Agent Hisashi Hoshino Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A plasma electrode comprising a fixing jig for attaching a reaction substrate to the lower surface of each electrode plate of a vertical multilayer parallel plate plasma electrode.