JPH05255843A - High purity titanium target for sputtering - Google Patents

Abstract

PURPOSE:To make the crystal grain size of a high purity Ti target used in a sputtering method utilized to form a film of a semiconductor device fine. CONSTITUTION:At least one kind of high purity grain growth inhibiting element such as Si, B or Ge is added to high purity Ti as the base of a target by a very small amt. of 100-2,000ppm by weight. The resulting target is grain-refined, particles scattered and deposited during sputtering are reduced and uniformity in film thickness is enhanced.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a high purity titanium target for sputtering.

[0002]

2. Description of the Related Art Conventionally, as a method of forming a thin film in a semiconductor device, a vacuum vapor deposition method having an evaporation mechanism, a sputtering method utilizing sputtering of a target by an inert gas ion, a CVD method and an ion plating method are known. However, in practice, the sputtering method is mainly used. The sputtering method is a method in which a target plate is bombarded with argon ions to release a metal, and the released metal is deposited on a device substrate to form a thin film. Therefore, the purity, the composition, the uniformity of the film thickness, etc. The nature of
It depends on the purity of the target plate material, composition sputtering characteristics, and the like.

[0003]

In the sputtering method which is mainly used as a film forming method for a semiconductor device, there are various kinds of materials for the sputtering target depending on the purpose of use. One of them is high-purity titanium. Targets are also often used. By the way, generally, in the sputtering method, undesired fine particles may be scattered during film formation, and these fine particles are deposited on the device substrate to form particles. Such particles cause defects such as disconnection in the device. Even in the case of a high-purity titanium target, there is no exception and it is desired to reduce the particles. Further, when the target is sputtered to form a film on the device substrate, the uniformity of the film thickness is important for improving the productivity, and further improvement of the high-purity titanium target is desired. In order to reduce the number of particles and improve the uniformity of the film thickness, it is an effective method to make the crystal grains finer in the polycrystalline body. In particular, it is said that the problem of film thickness uniformity arises from the fact that the sputtering efficiency varies depending on the orientation of each crystal grain on the target surface. It is considered that the film thickness can be made uniform. The crystal grain size can be reduced to some extent by optimizing the material processing method, the degree of processing, and the heat treatment (heat treatment for recrystallization) conditions, but there is a limit. It is generally difficult to optimize the conditions for miniaturization. Furthermore, the higher the purity, the larger the crystal grains grow, and the finer the grain becomes. Therefore,
An object of the present invention is to solve the above problems by achieving finer crystal grains in a high-purity titanium target for sputtering within a range that does not deteriorate the characteristics of film formation.

[0004]

In order to achieve the above object, the high-purity titanium target for sputtering according to the present invention comprises a high-purity titanium base material containing at least one high-purity titanium base material for the purpose of refining crystal grains. It is characterized by adding a trace amount of crystal grain growth suppressing element to form a dilute alloy. As the crystal grain growth inhibiting element to be added, one or more of high-purity silicon, boron and germanium can be preferably used. In addition, the amount of elements added is 20 by weight.
It is selected to be 00 ppm or less, preferably 100 ppm to 2000 ppm by weight.

[0005]

In the high-purity titanium target containing a small amount of the crystal grain growth suppressing element according to the present invention, the crystal grain growth is suppressed by the effect of the added element in the process of processing the molten ingot and the heat treatment, whereby Crystallized crystal grains are easily obtained.

[0006]

EXAMPLES The present invention will be described below with reference to examples. High-purity titanium with a purity of 99.99% or higher (however, metal component) and high-purity silicon with purity of 99.99% or more (however, metal component) is added by 100ppm to 2000ppm in weight ratio.
100 × L150) was manufactured. Forging and rolling were applied to this to form a plate with a thickness of 10 mm, and vacuum heat treatment was performed to manufacture a target. When the crystal grain size of the target thus obtained was observed, fine crystal grains of about 10 μm or less were obtained. As a comparative example, a high-purity titanium having a purity of 99.99% or more (however, a metal component) was used, and a molten ingot containing no silicon was manufactured in the same shape as that of the above-mentioned example. This was subjected to the same processing as in the above example, and the crystal grain size was observed to be about 40 to 50 μm. Therefore, in the target of the present invention, the crystal grain size is about
It is 1/4 to 1/5, and it is recognized that sufficient refinement of crystal grains can be obtained.

Although silicon (Si) is used as the additional element in the embodiments, one or more of boron (B), germanium (Ge) and the like may be added.

[0008]

As described above, in the target according to the present invention, the crystal grains of high-purity titanium are further miniaturized by containing a trace amount of the crystal grain growth suppressing element, and as a result, it is used for sputtering in the manufacturing process of semiconductor devices. By using it as a target, the product yield can be significantly improved.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshiharu Nozawa 4-4-295 Higashi-Shisui, Shisui-machi, Inba-gun, Chiba Prefecture (72) Masaharu Oshiro 76-4 Ehara Nitta, Sakura City, Chiba Prefecture

Claims (2)

[Claims] 1. A high-purity titanium base material containing at least one high-purity crystal grain growth inhibiting element in a weight ratio of 100 ppm to 2000.
High-purity titanium target for sputtering, characterized by being made a dilute alloy by adding a trace amount of ppm. 2. The high-purity crystal grain growth inhibiting element added to the high-purity titanium base material comprises one or more of high-purity silicon, boron, and germanium.
The high-purity titanium target for sputtering as described in.