JPS63241165A - Target for sputtering - Google Patents

Abstract

PURPOSE:To obtain a target for sputtering having a large area and satisfactory workability and used to form a magnetic thin film contg. a heavy rare earth metal and Fe as principal components by using a casting contg. a light rare earth metal and Mo, W, Tc or Re. CONSTITUTION:A target for sputtering used to form a magnetic thin film contg. a heavy rare earth metal (HR) and Fe as principal components is made of a casting contg. a light rare earth metal (LR) and one or more among Mo, W, Tc and Re. One or more among Gd, Tb and Dy are preferably used as the HR and one or more among Ce, Pr, Nd and Sm as the LR. The atomic compsn. of the target is represented by a formula [(LR)x(HR)1-y]yA100-y-zMz (where M is one or more among Mo, W, Tc and Re, A is elements including Fe and other than LR, HR and M, 0.05<=x<=0.60, 10<=y<=50 and 0<z<=15).

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a sputtering target used in the production of a heavy rare earth metal-iron alloy magnetic thin film used in an optical element.

[Conventional technology]

Conventionally, vacuum evaporation, sputtering, etc. are generally used to form heavy rare earth metal-iron alloy thin films.

Among these, the sputtering method is the most widely used method today because it can produce films with excellent magnetic properties compared to other film formation methods, and because mass production has improved significantly due to advances in the magnetron sputtering method. There is.

Methods for creating alloy thin films made of 92 or more elements by sputtering can be classified as follows depending on the structure of the sputtering target. ' ■ Method using a composite target ■ Multi-dimensional simultaneous sputtering method using multiple targets ■ Method using an alloy target Composite targets include so-called chip-on targets, in which chips of different metals are placed on a certain metal target.
There is an embedded target with a foreign metal embedded in the base metal. The composite target method is a method of controlling the composition of an alloy thin film by controlling the area ratio between different elements on the target surface. Therefore, in the chip-on-target method, the pellet area decreases as the target wears out, and the film composition changes, making it unsuitable for long-term film formation.The embedded target method has improved this drawback. be. Even if this target is consumed, the area ratio of each element region between the targets hardly changes, so even if film formation is performed for a long time, a constant composition of l[' can be obtained.

However, a common drawback of composite targets is that the arrangement of each element on the target surface results in fluctuations in composition within the film plane.

The multi-source simultaneous sputtering method (2) is a method in which high-frequency power or DC power is applied independently to multiple targets made of different materials to obtain a film that is alloyed with the substrate. On the one hand, the composition can be easily changed, but on the other hand, there are drawbacks, such as the need to prepare a plurality of sputtering electric ijXs, and the need to take measures against interference of high-frequency power between targets. Furthermore, since the film deposition rate and film thickness distribution from each target directly affect the film composition, changes in the deposition rate and film thickness distribution as the target wears out will result in a constant composition being uniform over the entire length of time. difficult to obtain.

■The alloy target is macroscopically in the direction of rhinoceros.

Since a film with a uniform composition can be obtained in any in-plane direction, even if sputtering is repeated many times, the composition of the film obtained will remain constant and uniform.

Alloy targets can be divided into sintered targets and cast targets based on their shield manufacturing method. The sintered target is
Although it can be made with a relatively large area regardless of the material, the impurity oxygen and nitrogen content must be reduced to 2000 ppm each.
Special techniques are required to reduce the amount below, which is inconvenient for producing a highly pure alloy thin film. On the other hand, a casting target obtained by crushing molten metal of a desired composition in an inert gas or vacuum has an impurity gas concentration of 50%.
It is possible to reduce the amount to 0 ppm or less, and a highly pure alloy thin film can be obtained.

As described above, the sputtering method using a cast target is most suitable for the industrial production of single-alloy thin films.

[Problem that the invention seeks to solve]

However, since heavy rare earth metals and iron form various intermetallic compounds, the ingot is brittle, and it is difficult to process it into a target shape or even to obtain a large-area ingot. The present invention is intended to solve these problems, and its purpose is to provide a high-purity alloy target by providing a heavy rare earth metal-iron alloy with a large area and good workability. It is in.

[Means for solving problems]

The sputtering target of the present invention is produced by sputtering using tB containing heavy rare earth metals and iron as its main components.
The sputtering target used to form the thin film is
Contains as a light rare earth element Xt component, and Mo, W, Tc
, R6 is characterized in that it is a casting containing at least one element 'lIA'lt.

[Implementation row] Hereinafter, the present invention will be explained in detail based on Examples.

The sputtering targets used in this experiment were: Unless otherwise specified, high-purity metal raw materials with a purity of 99.9% or higher were heated and melted in vacuum in an induction heating furnace, and then cast in an argon atmosphere. The material was processed into a disk having a diameter of 15 cm and a thickness of 5 rz*, and was further bonded to a backing plate made of a copper plate using indium solder. Moreover, the compositions shown below are atomic ratios.

Example 1 The composition is (NdzDyt-z)y (Fgo, 5ocoo
, 4e) An attempt was made to manufacture an alloy target with the composition shown in Table 1 when expressed as too-y-zyoz. As a result, samples 1 to 7, which are the implementation rows of the present invention, were all able to be used as good sputtering targets, but the comparison row
and 2 were broken during casting, and comparison row 3 was broken during processing, so they could not be used as sputtering targets.

Note that exactly the same results were obtained when W, TQ, and Rg were used instead of Mo.

Table 1 Actual column m 2 Sputtering target composition (HdzTbl-z)it (Feo, wrCoo,
u) When expressed as ym”os, the first shift of 2 is 0.05
, 0.20, 0.40, 0.60, and 0.80, we were able to process each composition as a sputtering target. , initial vacuum level 1
．． After evacuating the chamber to below 0XlO''''ro'rr, use Aff2XIU To as a carrier gas.
rr for 2 hours, and a high frequency power of 350 W was applied to the cand to form a film with a thickness of 50 nm on the glass substrate.

Note that a 1100-nm sleeping layer was formed following the formation of the aluminum simulated magnetic flux layer.

FIG. 1 is a plot of the coercive force obtained from the Kerr loop of the film thus obtained in terms of Nd and fkMz.

It can be seen that when X exceeds 0.6 gold, the coercive force decreases to 6k, making it impossible to obtain a sufficient magnetic percentage. M.

When W, Tc, and R were used instead of , the same results as those of our colleagues were obtained.

Implementation row 3 The composition of the sputtering target is (Ndo, arGdo, 2sDyo, so)26
When expressed as ('go・yoDyo−so)ys−2”g (one of each element MildQ, w, Tc tRg), for each M, Z = 1, 5, lo
.

Preparation of cast targets with compositions 15 and 20 [-- All samples were tried and could be used as targets for sputtering. These targets were then used to deposit on glass substrates in the same manner as in Example 2. A film was formed. FIG. 2 shows the Kerr rotation angle, and FIG. 3 shows the magnetic anisotropy constant, plotted against the M addition amount of 2. 2 is 15t-
If it exceeds 2≦, both the Kerr rotation angle and the magnetic anisotropy constant will rapidly decrease, which is not preferable for EB magnetic films.
The change at 15 is within an acceptable range, rather M
There are also products like o and W that improve magnetic customization.

Practical row 4 Comparison of the sputtering target of the present invention obtained by the casting method and the conventional sputtering target obtained by the sintering method All compositions were (Ndo, aDy@・ys)
Using these targets, n(Fg04c011.40)71MO4, formation was carried out under the same sputtering conditions as in Example 2. Here, the total thickness of the magnetic film is 40 nm, and the protective layer is made of silicon crab (5isN4.) 1100 nm.
n was used. Table 2 shows the Faraday rotation angle θ of these films.
? , Yasuda force Hc, anisotropy constant 1L, and the oxygen content W ("(0)) of each target obtained by pyrolysis. Also, the embodiment of the present invention is superior, but this is due to the difference in the oxygen cap contained in the target.

Table 2 [Effects of the Invention] As described in Table 2, according to the present invention, it is possible to easily obtain a sputtering target used for a single layer rare earth-iron km [lIm] by a casting method, and the sputtering target of the present invention can be easily obtained by a casting method. - Since the target has a small amount of rR, it has the effect of improving the magnetic properties of a film obtained by sputtering. Furthermore, since expensive and rare heavy rare earth elements can be replaced with light rare earth elements that are inexpensive and have abundant resources, raw material costs can be reduced.

In addition to the combinations shown in the implementation column, c instead of %Nd
The above-mentioned effects can be similarly obtained even when m, pr, and am are used alone or in combination, and Gd, Tb,
It was confirmed that similar effects can be obtained with combinations of Dy and two or more of Mo, W, 'rc, and R#.

[Brief explanation of drawings]

FIG. 1 shows (HdzTbl-z )o (Fllll, 60GO1
1,4(1)71 A diagram showing the relationship between coercive force and 2 of a film produced from a sputtering target having a composition represented by the composition formula 71MO11. Figures 2 and 3 are

Claims (1)

[Scope of Claims] (1) A sputtering target used for forming a magnetic thin film containing heavy rare earth metals and iron as main components by a sputtering method contains light rare earth metals as components, and contains Mo, W, Tc, Re, sputtering, characterized in that it is a cast product containing at least one or more elements of
target. (2) The heavy rare earth metals (HR) and light rare earth metals (
LR) are respectively Gd, Tb, Dy and Ce, Pr, N
d, Sm, and the composition of the sputtering target is {(LR)_x(HR)_1_-_x}_yA_1_0 in atomic ratio.
When expressed as _0_y_−_zM_z (where M is Mo, W
, Tc, one or more elements selected from Re, A represents an element other than iron (LR), (HR), M), x, y
, z are in the range of 0.05≦x≦0.60, 10≦y≦50, 0<z≦15, respectively.