JPS62211371A - Sputtering device - Google Patents

Abstract

PURPOSE:To form thin films of target metals having excellent characteristics on the surfaces of substrates to be treated by forming the metallic targets in a sputtering device to a flat plate shape, disposing plural sheets of such targets in an annular shape and rotatably providing a counter electrode coaxially attached with the substrates to be treated to the outside periphery thereof. CONSTITUTION:Plural sheets of the plate-shaped metallic targets 17 are combined to the central part in a vacuum vessel 11 in such a manner that the section thereof forms the square or polygonal annular shape. A holder 15 attached with the substrates 14 to be treated and to be formed with the thin films is disposed to the outside thereof. After the inside of the vacuum vessel 11 is evacuated to a vacuum, a treating gas such as Ar, O2, N2 or H2 is introduced from a gas introducing device 13 into the vacuum vessel. A high voltage is impressed to the targets 17 and the holder 15 which is the counter electrode by a power source 19 to generate a discharge, by which the Ar, etc., are ionized. The ions bombard the targets 17 and the target materials splashed from the targets in this stage are made to collide against the surfaces of the substrates 14 while the holder 15 is rotated by a driving device 16. The thin films of the target materials having compressive stress are thus uniformly formed on the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to semiconductor devices such as ICs and LSIs, electrical and electronic devices such as thermal heads and display panels, and protective and decorative coatings. The present invention relates to a sputtering apparatus used in technical fields requiring formation.

BACKGROUND OF THE INVENTION Various techniques have been developed to form thin films, including vacuum evaporation, sputtering, CVO, and electron beam evaporation in recent years. The sputtering method is one of the widely used film forming methods, and the types of equipment themselves vary widely, from small ones used in laboratories to large ones used as mass production equipment in factories. In addition, with one type of magnetron sputtering using m-field, sputtering efficiency,
Therefore, the #M film speed can be increased, and it is used in most sputtering apparatuses today. The main reasons why the sputtering method is widely used are (a) that it is a relatively low-temperature process;
b) Examples include scales that form not only metal films but also compounds, insulators, and other films.

Most sputtering devices are of the parallel plate type, and the target is usually a cathode, the object to be processed, such as a substrate, on which a film is to be formed is placed on the opposite electrode side, and an inert gas (argon is used in many cases) is placed on the opposite electrode side. Introduce. By applying a high voltage to this system, ionized gas atoms bombard the target, and the scattered target material adheres to the surface of the object to be processed, thereby forming a film.

A drum-type sputtering device is also used, and as shown in Fig. 4, a workpiece 3 is mounted on a drum 2 at the center within a vacuum N1, and one or more sputtering devices are placed on the outer periphery. A target 4 is installed, and the drum 2 is rotated during sputtering to obtain uniformity of the coating.

Problems to be Solved by the Invention When using the above-mentioned sputtering apparatus, the properties of the film formed depend on the film forming conditions, such as discharge gas pressure, input power, film formation speed, temperature, etc., and the target 5.
#J quality is affected by, for example, atomic weight, whether it is a metal or a non-metal, etc.

When the formed film is used electrically, its sheet resistance, when used optically, its reflectance or transmittance, and when it is used as a protective film, its chemical stability and mechanical properties are determined. Strength is an important point. Although the properties of these films can be controlled to some extent by the film forming conditions as described above, there are limits to this. For example, in order to maintain a stable discharge for sputtering, a pressure of about 10' Torr or more is required, and the maximum possible temperature of the object to be processed during film formation depends on the material. Number 10 for glass
The limit is 0°C.

Although it is easier to obtain a film with better uniformity with a drum-type sputtering device than with a parallel plate type, the properties of the film, such as hardness and internal stress, are not significantly different between the two. , no significant improvement or change in film quality can be expected.

Therefore, if the necessary properties cannot be obtained within the range of possible film-forming conditions, film formation may become impossible unless it is possible to choose another film-forming method or change the material. Put it away.

An object of the present invention is to provide a sputtering device with an improved electrode configuration as a method for easily changing the properties of a film that are difficult to improve with conventional parallel plate type or drum type sputtering devices. .

Means for Solving the Problems The present invention solves the above-mentioned problems. A flat plate type target is used as a target, and a plurality of targets are arranged in a ring shape in the center of a vacuum chamber, and a coaxial shape is placed around the outer circumference of the target. A counter electrode is provided on the opposite electrode, and the object to be processed is attached to the opposite electrode at Vt.

Effect: With the above structure, the stress in the film can be kept to a very weak tensile stress, and it is possible to form a film with properties that cannot be obtained under conventional film forming conditions in a parallel plate type sputtering device or a drum type sputtering device. It becomes possible.

EXAMPLE An example of the present invention will be described below with reference to the drawings. A flat plate type target is used as the target, and although the number of targets can be n (n=2.3.4...), the case of four targets will be explained as an example.

FIG. 1 shows the basic configuration of a sputtering apparatus.

The vacuum chamber 11 is approximately 10''
Exhaust to the Torr level. Further, processing gases necessary for film formation, such as Ar, 02, N2, and N2, are introduced into the vacuum chamber 11 by the gas introduction device 13. The object to be processed (for example, a substrate) 14 is mounted on a holder 15 forming an electrode, and this holder 15 is connected to a driving device 16, which rotates the holder 14 during film formation to ensure uniformity. It has been devised so that a good film can be obtained. 17 is a target, 18 is a cooling water system for the target 17, and 19 is a power supply device that applies voltage between the target 17 and the holder 15.

FIG. 2 shows a schematic diagram of the central target portion of the apparatus of FIG. 1, viewed from above. The target 17 is fixed to a backing plate 20, and the backing plate 20 is made of a metal with good thermal conductivity such as copper, so that the cooling water system 18 can effectively cool the target 17. A magnet 21 is installed on the back side of the target, and the magnetic field generated by this increases the frequency of collisions between electrons and gas atoms, and serves to confine the plasma.
Improves sputtering efficiency. The four targets 17 are arranged in a ring shape.

When a high voltage is applied by the power supply device 19 between the electrodes to which the target 17 and the object to be processed on the outer periphery are attached, a discharge occurs between the two electrodes, the target 17 is bombarded with ions, and the scattered target material is 5I! lLy! ! It adheres to the surface of the object 14 and forms a film.

An example of the properties of a film formed by this method is shown in FIG. This is a view of the internal stress of the film in relation to the gas pressure during film formation.
33 and 34 indicate Or and Ta films formed using the apparatus shown in FIG. 1, respectively. The temperature during film formation was room temperature, and the film thickness was the same (for example, 1500
person).

In the case of Cr, it is difficult to form a film that exhibits compressive stress within the range of gas pressure that can be discharged using a normal parallel plate sputtering device, and it tends to exhibit strong tensile stress, resulting in surface cracks. etc. are likely to occur. If this is formed using the apparatus shown in Figure 1, it is possible to limit the stress to a very weak tensile stress, or if discharge is performed at a low pressure, it is possible to form a film that exhibits compressive stress. Problems such as cracking can be avoided. Also, Ta
Although the difference is not as remarkable as in the case of Qr, it is possible to change the internal stress within the normally used discharge gas pressure range.

Effects of the Invention According to the present invention, since an inner electrode in which a flat plate target is arranged in an annular manner is used, it is possible to use a conventional parallel plate type or drum type sputtering apparatus within the range of production and removal conditions normally possible in a sputtering apparatus. Difficult improvements in film properties, such as avoiding internal stress problems, can be easily achieved.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram of a sputtering apparatus showing an embodiment of the present invention, FIG. 2 is an explanatory diagram illustrating an electrode configuration of the present invention, and FIG. 3 is a stress stress of a film formed by the apparatus shown in FIG. FIG. 4 is a schematic diagram of a conventional drum-type sputtering apparatus. 11... Vacuum chamber, 14... TM physical object, 15...
Holder, 16... Holder drive device, 17... Target, 19... Power supply device, 20... Backing plate, 21... Magnet agent Yoshihiro Morimoto 1st Figure 7, -Kokusu 14- Ruthing/Tar --- Wood I Leder 17-m-Dar White L/-1 List Rinju Figure 2 21--77" volume/y) Figure 3 Sufu Su 1 Pressure-h (Tarr-n Figure 4

Claims (1)

[Scope of Claims] 1. A sputtering device comprising an inner electrode and an outer cylindrical electrode installed in a vacuum container, and the inner electrode is constituted by a plurality of flat targets arranged in a ring shape. 2. The sputtering apparatus according to claim 1, wherein metal is used as the target material.