JPH03122274A - Production of thin film and device thereof - Google Patents

Abstract

PURPOSE:To stably obtain a stable discharge characteristic, uniform film thickness distribution and uniform film characteristics over a long period by alternately arranging targets for film formation on both surfaces of substrates apart to the distance at which the interference between high frequencies does not arise from the faced positions. CONSTITUTION:The front and rear targets 11, 13 and 12, 14 of the device for inline production of thin films are alternately arranged apart to such distance at which the high-frequency powers to be impressed thereto do not interfere with each other. The distance to be parted is determined by the sizes of the cathodes and targets 11 to 14, the conditions of the film forming chamber, sputtering conditions, etc. Further, the substrates 5 to 10 and substrate holders 2 to 4 are rotated or advanced in parallel. The different regions of the substrate holders 2 to 4 act as anode in such a manner and the mutal interference between the front and rear high-frequency electric powers is lessened. The stable film deposition is, therefore, executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thin film manufacturing method and apparatus for forming thin films on both the front and back surfaces of a substrate by high frequency sputtering.

[Prior Art] Conventionally, when forming thin films on both sides of a substrate by sputtering, a configuration as shown in FIG. 4 is common.

The substrate 3 and the substrate holder 2 are placed in a position sandwiched between two directly facing targets 11 and 12. Although the substrate 3 and the substrate holder 2 may be stopped, rotated, or translated, the relative relationship between the opposing targets 11, 12 remains unchanged. For this reason, in the case of so-called high-frequency sputtering in which radio frequency (RF) power is supplied to a target to cause discharge, interference occurs between the high-frequency powers supplied to the opposing targets 11 and 12, making the discharge unstable. In severe cases, arcing occurs frequently and normal sputtering cannot be performed.

In order to eliminate instability caused by interference between opposing high-frequency powers, for example, it is possible to slightly shift the frequencies so that they are not the same, or to branch them from the same oscillator and use a phase shifter to keep the mutual phase difference constant. We are controlling it to maintain it. However, although this method alone is highly effective in improving the stability of discharge, it is necessary to obtain uniform film thickness over the entire film formation area on both sides, and to improve electromagnetic and optical properties. However, it was not sufficient to stably obtain film properties such as - for a long period of time.

In particular, in large-scale mass production equipment, for example when forming a multilayer film, two or more targets are often installed and the same number of high frequency powers are applied. In such cases, due to mutual interference between multiple high-frequency powers, the in-plane uniformity and temporal stability of the film properties change significantly, and since these changes do not have a fixed tendency and have poor reproducibility, control is difficult. The problem was that it was difficult.

[Problems to be Solved by the Invention] The purpose of the present invention is to improve these problems and to stably obtain stable discharge characteristics, uniform film thickness distribution, and -like film properties over a long period of time. It is an object of the present invention to provide a thin film manufacturing method and apparatus using a high frequency sputtering method that can perform the following steps.

[Means for Solving the Problems] The sputtering apparatus of the present invention has alternately arranged targets, in which the targets for forming films on both sides of the substrate are separated from the opposing arrangement by a distance that does not cause interference between high frequencies. .

That is, the present invention is a method of forming thin films on both the front and back surfaces of a substrate by high-frequency sputtering, in which targets on the front and back sides are provided at a distance so that the high-frequency powers on the front and back sides do not interfere with each other. The present invention provides a thin film manufacturing method characterized by the following.

The present invention also provides a sputtering apparatus for forming thin films on both the front and back sides of a substrate by high-frequency sputtering method.
The present invention provides a thin film manufacturing apparatus characterized in that targets on the back side are provided at a distance such that high frequency powers on the front and back sides do not interfere with each other.

Here, the terms "front and back" of the board originate from the fact that when one side is called the front side, the other side is called the back side, and does not mean any particular discrimination.

FIG. 1 shows the main parts of an in-line thin film manufacturing apparatus according to an embodiment of the present invention. The configuration of the present invention will be explained using FIG. 1. However, the present invention is not limited to this diagram. In the method and apparatus of the present invention, the front and back targets, which were conventionally placed facing each other, are alternately arranged at a distance such that the high frequency powers applied to the front and back targets do not interfere with each other. do. This separation distance can be determined by the dimensions of the cathode and target, the geometrical conditions of the film forming chamber, the sputtering conditions, etc. Further, by rotating or translating the substrate and the substrate holder, the thickness of the formed thin film can be made uniform.

FIG. 2 shows a so-called in-line sputtering apparatus in which a target is arranged in-line to form a multilayer film as an embodiment of the apparatus of the present invention. Targets for sputtering the front surface of the substrate and targets for sputtering the back surface of the substrate are arranged alternately (staggered) on both sides of the substrate at appropriate distances.

Furthermore, in order to enhance the effect of preventing mutual interference between high-frequency powers on the front and back sides, a member having a function of shielding electromagnetic waves can be provided between the front and back targets that are spaced apart in the apparatus of the present invention. The material and shape of this member can be selected to suit the purpose of providing the member described above. As for the shape, for example, a plate shape, a box shape, etc. can be selected.

Furthermore, in the present invention, the thin film-formed object may be a thick substrate such as a block-like object in addition to a plate-like object.

[Function] In high-frequency discharge, as in the case of direct current (DC) discharge, the target operates as a cathode, and the substrate and substrate holder operate as an anode.

That is, in FIG. 4, which shows the arrangement of conventional opposing targets, the front and back sides of the same portion of the substrate 5 or substrate holder 2 simultaneously act as anodes for the two opposing cathodes 15 and 16. In other words, two cathodes share one anode. Therefore, interference between the two high frequency powers is very large. In the present invention, since the two opposing cathodes on the front and back sides are separated from each other, different regions of the substrate holder act as anodes, and mutual interference between high-frequency power on the front and back sides is significantly reduced.

[Example] FIG. 2 shows an example of a double-sided sputtering apparatus capable of forming a multilayer film in-line as an example of the present invention. The multiple substrates mounted on the substrate holder enter the film forming chamber through the door valve by the transport system, pass sequentially through the film forming zone in front of the targets ■ to ■, forming multilayer films on both sides, and then pass through the door valve ■. The substrate holder is loaded with a new substrate and transported to the deposition chamber at regular intervals.

Several substrate holders are always present in the film deposition chamber.

Usually, the front and back sides have the same film composition, so targets ■ and ■,
■ and ■.

■ and ■ are often made of the same material. In FIG. 2, the gas introduction system and exhaust boat are omitted for simplicity. In this example, the target size is 200 width x
It is held vertically at a height of 600 mm. By setting the distance between each target to 800 mm, the film thickness distribution of the substrate in the substrate holder (500 mm high x 600 mm wide) was improved. For example, in a single-layer film, when targets ■ and ■ are placed opposite each other, the film thickness distribution inside the substrate holder will be approximately ±
What was 10%, targets ■ and ■ are 800m
By separating the distance by m, the station was improved to about ±5%. In this embodiment, a box-shaped grounded shielding plate is placed between the targets (1) and (2) to reduce the interference effect.

FIG. 3 shows another embodiment of a double-sided sputtering apparatus having a rotating disk-shaped substrate holder 2. In FIG. In FIG. 3, a plurality of substrates 5, 6, etc. are mounted on a substrate holder 2, and the substrate holder is rotated by a motor 31 from the outside. The high frequency cathodes 15 and 16 on both the front and back surfaces are arranged diagonally to each other and are sufficiently spaced apart. Therefore, the negotiation between the high-frequency powers applied to the bipolar sword is kept to a minimum, and stable film deposition is achieved.

[Effects of the Invention] As explained above, the present invention provides targets for forming a thin film on each of the front and back surfaces of a substrate at a distance so that the discharge powers on the front and back sides do not interfere with each other. This arrangement has the effect of stabilizing the discharge, improving the characteristics of the thin film formed, and in particular, significantly improving the uniformity of film thickness and temporal stability.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of essential parts of an embodiment of the apparatus of the present invention, FIG. 2 is a horizontal cross-sectional view of an in-line sputtering apparatus according to an embodiment of the present invention, FIG. 3 is a cross-sectional view of another embodiment, and FIG. The figure is a schematic diagram of a conventional example. The symbols in FIGS. 1, 3, and 4 are as follows. ■...Vacuum chamber 2.3.4...Substrate holder 5.6, 7, 8, 9. to... Boards 11, 13...
...Targets 12, 14 for surface sputtering...Targets 15, 17 for back sputtering...Cathodes 16, 18 for surface sputtering...Cathodes 19, 20, 21, 22... for back sputtering matching circuit 23,
24.25.26...High frequency power supply 27゜29...30...31...28...Door valve...Vacuum exhaust port...Gas introduction pipe...Substrate holder rotation motor

Claims (5)

[Claims] (1) A method of forming thin films on both the front and back sides of a substrate by high-frequency sputtering, characterized in that the targets on the front and back sides are provided at a distance so that the high-frequency powers on the front and back sides do not interfere with each other. A thin film manufacturing method. (2) A sputtering device that forms thin films on both the front and back surfaces of a substrate using a high-frequency sputtering method, in which targets on the front and back sides are provided at a distance that prevents the high-frequency powers on the front and back sides from interfering with each other. Features of thin film manufacturing equipment. (3) The thin film manufacturing method according to claim 1, wherein at least one of the front and back targets is composed of a plurality of targets and arranged in-line. (4) The thin film manufacturing apparatus according to claim 2, wherein at least one of the front and back targets is composed of a plurality of targets and arranged in-line. (5) The thin film manufacturing apparatus according to claim 2, characterized in that a shielding member is provided between the front and back targets that are spaced apart from each other.