JPH09228037A - Target for forming compound thin coating at high speed and evaporating source - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a reactive sputtering target capable of depositing compound thin coating and usable at a perfect utilizing rate by forming the target of a mixture of metal and partial metallic compounds or of the one obtd. by integrating and fixing the same. SOLUTION: A sputtering target is formed of a mixture of metal (single metals, allays, intermetallic compounds, the mixtures of metals or the like) and partial metallic compounds or the one obtd. by integrating the same. For example, in the case titanate zirconate is deposited by a reactive sputtering method, PbO is placed on a Zr-Ti alloy target to form into a feeding source of Pb and oxygen. Since this mixture is brought into reaction at a flow ratio of the metal mode on a substrate and is deposited, the depositing rate is high. By using the target, compound thin coating of oxide, nitride, sulfide, carbide or the like such as superconducting ceramic thin coating, ferroelectric ceramic thin coating and optical thin coating is formed. The deposition of the thin coating may be executed not only by a sputtering method but also by a physical method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of constructing a target and an evaporation source for high speed deposition of a compound thin film by a sputtering method and a physical deposition method.

[0002]

2. Description of the Related Art There are two methods for forming a compound thin film by a sputtering method. Compounds formed by reacting metal and gas (oxygen source, nitrogen source, carbon source, etc.), eg ZnO, Si
For O ₂ , AlN, ZrN, etc., a method of sputtering by adding O ₂ or N ₂ reaction gas to an inert gas using a metal target and a ceramic target of the same composition as the finally required thin film composition (Ar + O ₂ ) Similarly, there is a method of sputtering. However, the method using a metal target is called a metal mode when the ratio of (active gas / inert gas) is small, and metal is mainly deposited, and when the ratio of (active gas / inert gas) is large. Is called a compound mode, and a compound thin film can be deposited. However, the compound mode deposition rate is often slow. When a ceramic target is used, the deposition rate is slow as in the compound mode described above, but using magnetron sputtering alleviates this drawback. However, the gas component of the compound often becomes high-speed neutral particles and impacts the deposited film, causing a composition shift or reducing the deposition rate only in that part. Therefore, it is desirable to reduce oxygen and other elements in the target as much as possible.

FIG. 1 shows the relationship between the deposition rate and the flow rate ratio of oxygen to argon when a ZrO ₂ thin film was deposited by a reactive magnetron sputtering method using a metal target. The part where the deposition rate is high is the metal mode (Fig. 1, A
The metal thin film is deposited when the distance between the substrate and the target is narrow, and it is possible to deposit the compound thin film when it is wide, but the deposition rate is slow. At 8%, the deposition rate suddenly decreased by one digit or more, but here it is called compound mode (Fig. 1, C → D) because the target surface is covered with oxide and an oxide thin film is deposited. . When using a ceramic target, there is a problem that the deposition rate is slower than that of metal as in the compound mode.

[0004]

By the way, when the compound thin film is deposited by the sputtering method, it is prepared only by using the metal target or the ceramic target as described above. Therefore, there is no choice but to sacrifice the deposition rate or to sacrifice the target utilization rate by magnetron sputtering, and it was impossible to deposit at a high utilization rate of 100%.

The present invention is intended to solve the above problems, and what we define as a quasi-metal mode of reactive sputtering is when a compound pellet is placed on a metal target (active gas / inert gas). When the deposition rate is examined by changing the flow rate ratio, the compound thin film is deposited at a gas flow rate ratio between the metal mode and the compound mode, which is as high as the metal deposition rate. It is an object of the present invention to provide a mixture target for depositing at a target utilization rate of 100%, which is sufficiently fast even with a normal sputtering method.

The mixture target of the present invention is a mixture of a metal and a metal compound or a mixture thereof which is integrated and solidified. Utilizing the fact that the metal deposition rate is faster than the compound deposition rate, The gas component is supplied partly from the introduced gas and partly from the compound element mixed in the target, and mainly reacts on the substrate, so the compound deposition rate is faster than the metal deposition rate. In other words, the major feature of this target is that the compound elements are added to the metal target, adjusted and mixed. By doing so, the compound thin film can be deposited at a high speed even in the region of the flow rate (active gas / inert gas) in the metal mode.

[0006]

According to the present invention, since the mixture target is reacted and deposited on the substrate at the metal mode (active gas / inert gas) flow ratio, the deposition rate is high. Therefore, the deposition rate is sufficiently high without necessarily using the magnetron sputtering apparatus, and the deposition rate is high even with the normal bipolar sputtering apparatus, and the target utilization rate is 100%. If this target is used in a magnetron sputtering system, the utilization rate will drop to a value determined by the system, but the deposition rate will be even faster than in conventional methods. Normally, when the input power is increased to increase the deposition rate in the compound target, abnormal discharge occurs, but in this method, it is in the metal mode,
Since the target contains a large amount of metal, its generation is essentially extremely small.

[0007]

EXAMPLE FIG. 2 illustrates the process leading to the invention of a mixture target. For example, lead zirconate titanate _{(PZT: Pb (Ti x Zr} ) O 3) and, when depositing by reactive sputtering, so that the use of ceramic targets for Pb-Zr-Ti alloy or PZT.
In the quasi-metal mode in which oxygen which is deficient in the metal mode is supplied from the solid oxygen source and the metal reacts with oxygen on the substrate to deposit PZT at high speed, it is necessary to prepare the solid oxygen source in the metal in advance. 100m diameter for PZT
m Zr—Ti alloy target (1 in FIG. 2) on a disc-shaped PbO pellet (diameter 13 mm and thickness 2 mm) (FIG. 2).
No. 2) is added so that the area ratio is about 40% to serve as a supply source of Pb and oxygen. In this way, a small oxygen flow rate ratio (O ₂ / Ar) of 2.1%, which is usually the metal mode, is obtained.
Despite + O ₂ ), a PZT thin film having a perovskite structure could be formed at a deposition rate of ~ 12 μm / min at an input power of 200 W, a substrate temperature of 450 ° C, and a wide range of 450 to 540 ° C. . This is sufficiently fast considering that the reported data by many magnetron sputtering methods is 2 to 12 μm / min.

FIG. 2 shows a disk-shaped Pb on a metal target.
It is a target that succeeds in low temperature and high speed deposition in the quasi-metal mode by adding O. If a target having the same effect as this is produced by another method, a hole having the same diameter may be formed in the alloy target instead of the PbO disk, and PbO powder may be compressed and filled therein, as shown in FIG. This way, there is no difference in the action of both. Next, even if the target of FIG. 3 was crushed and solidified again as shown in FIG. 4, the effect should be exactly the same although the shape became micro. in that case,
Even if the metal and the metal compound component are mixed from the beginning as shown in FIG. 4, the effect remains the same. Thus, Zr-Ti alloy and P
The target for reactive sputtering is a mixture or compound of bO.

[0009]

As described above, in the present invention, the compound target can be deposited at a high speed in the quasi-metal mode by using the mixture target. Even if this is used in a normal sputtering apparatus, the deposition rate is about the same as in the case of magnetron sputtering and the target utilization rate is 1
00%. Further, since the reaction is performed on the substrate to form, the thin film forming temperature is lowered, it is possible to prevent mutual diffusion such as artificial lattice film formation, and it is possible to reduce the generation of arc during the formation of the compound thin film.

[Brief description of drawings]

FIG. 1 Deposition rate and oxygen gas flow rate ratio in reactive sputtering

FIG. 2 Metal-metal oxide composite target

FIG. 3 Virtual metal-metal oxide composite target

FIG. 4 Metal-Metal Oxide Mixture Target

[Explanation of symbols]

1 ... Metal target 2 ... Metal oxide, 3 ... Metal oxide, 4 ... Metal, 5 ... Integrated mixture of metal and metal oxide, can be used as powder

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C23C 14/28 C23C 14/28 14/32 14/32 A

Claims (3)

[Claims] 1. Preparation of a compound thin film by a sputtering method, for example, a so-called oxide such as a superconducting ceramic thin film, a ferroelectric ceramic thin film, a transparent conductive thin film, an optical thin film, or a compound thin film such as a nitride, a sulfide, or a carbide. The sputtering target used in the creation was a metal (single metal,
Alloy, intermetallic compound, metal mixture, etc.) and a mixture of some metal compounds, or a combination of them, which makes it possible to deposit a compound thin film faster than the deposition rate in the metal mode of reactive sputtering. 2. The compound is deposited in the metal mode in claim 1, so that a component insufficient in supply from a gas is added as a metal compound, and the thin film is mainly the metal and the gas on the substrate and the gas contained in the target. A target for reactive sputtering, which is capable of reacting with a seed and depositing. 3. The material is not limited to the sputtering method of claim 1, but is deposited by the same physical method (PVD method), such as laser ablation method, reactive deposition method, ionization deposition method, ion plating method, etc. A target for reactive thin film deposition, which is a mixture of a metal (a single metal, an alloy, an intermetallic compound, a mixture of metals, etc.) and a part of a metal compound, which is characterized by reactively depositing a compound on a substrate. And evaporation source.