JPS6396261A - Chromium-based alloy for vapor deposition - Google Patents

Abstract

PURPOSE:To obtain a chromium-based alloy which permits stable and efficient formation of a thin high-characteristic film contg. impurities at a lower ratio, by specifying a compsn. consisting of Al, Ca, O, N, and Cr. CONSTITUTION:This chromium-based alloy for vapor deposition contains <=1wt% A, <=200ppm Ca, <=400ppm O, and <=200ppm N, contains further <=1% Ti at need and consists of the balance substantially Cr. This alloy is adequate for production of the thin chromium film which contains the impurities at the lower ratio, has the high characteristics and is used as a protective film or underlying material for thin magnetic films. The above-mentioned alloy is easily obtd. by smelting metal or alloy materials, which are Cr, and Al, and in some cases, Ti for the purpose of alloying, in a vessel having the inside surface constituted of CaO-based refractory materials in a nonoxidizing atmosphere.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a chromium-based alloy for vapor deposition, particularly as a protective film or base material for magnetic thin films used for LSI photomasks, magnetic recording disks, and tapes. The present invention relates to a chromium-based alloy for vapor deposition suitable for producing pure chromium thin films.

[Prior Art] [Photomasks for LSI manufacturing are made by sputtering or vacuum evaporation using a target material of pure chromium. Furthermore, magnetic recording materials in which a magnetic alloy thin film is formed on a nonmagnetic substrate are well known.

Vapor deposition methods such as sputtering, vacuum evaporation, and ion blasting are widely used as methods for producing thin films of magnetic recording materials, their base films, and protective films.

In particular, the sputtering method is advantageous in that it is possible to obtain a compositionally uniform thin film while controlling the pressure inside the sputtering device, as long as a target material containing a certain alloying element with a uniform internal composition is obtained. be.

Conventionally, pure chromium or its alloys have been used as base films and protective film materials for magnetic recording materials. , N1-C.

It is widely used as a protective film and base material for magnetic recording materials (mainly used as magnetic recording materials).

[Problems to be solved by the invention] After conducting various studies on conventionally used chromium-based alloys, we found that they contain relatively large amounts of inclusions such as oxygen, nitrogen, sulfur, carbon, and other metal oxides. It has been found that the resulting thin film has poor corrosion resistance, homogeneity, smoothness, etc., and has a significant adverse effect on the magnetic properties of the magnetic recording material produced.

[Means for Solving the Problems] In view of the above-mentioned conventional circumstances, the present invention has been made in order to provide a chromium-based alloy for vapor deposition that can stably and efficiently obtain a high-performance thin film with a low impurity content. and Afi 1% by weight or less, CCa 200pp or less, 04oo
ppm or less, NN200pp or less, the balance being substantially Cr, and A11% by weight or less, Ti1% by weight or less, CCa200p.
The gist of the present invention is a chromium-based alloy for deposition, characterized in that it contains 400 pp or less of 0O, 400 pp or less of NN, and 200 pp or less of NN, with the remainder being substantially Cr.

That is, in order to solve the problem caused by impurities in the vapor deposition alloy and obtain a thin film with high characteristics, the present inventor has made extensive studies and found that a specific amount of Ca and An may be added to the vapor deposition chromium-based alloy. Furthermore, by including Ti, an alloy with low impurity content can be obtained, and the getter action of Ca, Au2, and Ti also reduces the gas component in the vapor deposition atmosphere, resulting in an alloy with extremely high purity and high characteristics. They discovered that a thin film can be obtained and completed the present invention.

Hereinafter, the present invention will be explained in detail.

In addition, in this specification, "%" represents "weight%."

The chromium-based alloy for vapor deposition of the present invention is used as a material for vapor deposition in vacuum vapor deposition, sputtering, ion blating, etc., and is used for manufacturing bases and protective films for magnetic thin films, and its composition is as follows: It is as follows.

Cr: remaining Aflt 1% or less Ti: not contained (first invention) or 1% or less (second invention) Ca: 200 ppm or less ○: 400 PI) m or less N: 200 ppm or less Limiting the alloy composition of the present invention Let me explain the reason.

AA and Ti work together with Ca to clean the alloy when melting the alloy, and also have a getter action to trap gas components in the vapor deposition τ atmosphere. However, the amount of 81 Ti is too large and it is not preferable that the amount affects the alloy properties. Therefore, in the present invention, Af
11% or less, or 21% or less of Au and 1% or less of Ti.

Naturally, if the amount of Ti is too small, sufficient effects of the above-mentioned cleaning action and getter action cannot be obtained. In the present invention, Au2 is 0.0
1 to 1.0%, or 0.01 to 1.0% of Au and 0.01 to 1.0% of Ti, more preferably 0.02 to 0.2% of Au2 or the total amount of Au and Ti. is desirable. Note that An and Ti are solid solution A11 solid solution T
Since the effects of the present invention are achieved by existing in the alloy in the form of An and Ti, it is important that the form of existence of An and Ti is in a solid solution state.

As mentioned above, Ca works together with Ti to clean the alloy and also has a getter action. If the content of Ca is too large, it may affect the alloy properties and may also cause the alloy to become brittle due to the precipitation of intermetallic compounds and the like.

Therefore, in the present invention, the Ca content is 200 ppm.
The following shall apply. On the other hand, if the Ca content is too low, sufficient cleaning and gettering effects due to Ca will not occur. For this reason, the Ca content is 5 to 200 ppm, especially 1
It is preferably in the range of 0 to 30 ppm.

Note that since the effects of the present invention cannot be achieved when Ca is in the form of CaO or Ca0-AfL203, Ca in the alloy is
It is important that the existing form of is metallic Ca.

If the amount of O and N in the alloy is too large, the degree of vacuum in the vapor deposition atmosphere will deteriorate when the alloy is used for vapor deposition, and good vapor deposition will not be possible, making it impossible to obtain a magnetic thin film with high characteristics. Therefore, the O content in the alloy is 400 ppm or less, preferably 300 ppm or less.
ppm or less, and the N content is 200 ppm or less, preferably 1100 ppm or less.

In the present invention, it is not a particular problem that impurities such as Si, Mn, P, and S are unavoidably contained in the alloy. It is better to reduce other impurities in the material as much as possible, for example, the St content is 0.1% or less, the Mn content is 0.05% or less, the P content is 8ppm or less, and the S content is 30ppm or less. is preferred.

Such a chromium-based alloy for vapor deposition of the present invention can be manufactured, for example, according to the method described below.

That is, first, Cr, An, and optionally T are added for alloying.
The metal or alloy material i is heated in a container whose inner surface is made of a CaO-based refractory material in a non-oxidizing atmosphere such as a vacuum or an inert gas atmosphere such as argon by a conventional method such as high frequency or low frequency conduction heating. By heating and melting using a method or the like, a molten alloy having a desired composition is obtained.

In the present invention, Ca constituting the inner surface of the container used
O-grade refractory materials include calcia (Cab) and Ca.
Examples include O-enriched dolomite, and fused calcia is particularly preferred.

Such calcia furnace material has a CaO content of 60
% or more, especially 80% or more is preferable.

CaO has a high melting point and is extremely stable at high temperatures, making it possible to obtain a highly clean molten metal without producing metal oxides and contaminating the molten metal with impurities during melting.

In particular, when a container whose inner surface is made of a CaO-based refractory material with a high CaO content is used, it is extremely advantageous because it achieves excellent effects such as zero removal, S removal, and inclusion removal.

Moreover, since AfL and T 1 exist in the molten metal, ? 8
In hot water, zero and sulfur removal occurs, and along with this, nitrogen removal also occurs. Furthermore, Ca is leached into the molten metal due to the reaction between CaO and Al in the furnace wall material. That is, An reacts with O in the molten metal, CaO on the furnace wall, and S in the molten metal to form CaO+ 5-4Ca S + 0, and reacts with the generated O to form 2AfL+30→Au203, producing AfL203. Furthermore, Al in the molten metal reacts with CaO on the furnace wall to form 2An+3CaO-+An203+3Ca (g), which also produces Au2203.

(In this case, the generated Ca becomes a gas) and escapes from the system, but a portion remains in the alloy to satisfy the Ca content of the alloy of the present invention. ) AfL203 reacts with CaO on the furnace wall as shown in the following equation, and 3
An active layer of CaO.Au203 or 12CaO-7AIL203 is formed on the furnace wall surface.

A II 203 + 3 Ca O-= 3 Ca
O-A J22037AJZ203+12CaO" 12CaOH7Af1203 KO') 12CaO+ 7AJZ203 and 3CaO-
Au203, especially 3Cao-Af12o3, has a high ability to remove S from the molten metal, and S removal progresses well.

In this way, Al causes de0, and Ca generated by the reducing action of AIL and active 3Cao-AJ in the crucible type.
S removal is performed by 12o3.12cao.7AfL203 and CaO.

Further, N in the molten metal is removed from the molten metal due to evaporation (boiling) of Ca, etc. generated by the reaction between An and CaO, and the amount of N in the molten metal is also reduced.

When Ti is added, it complements the action of Au2 and further increases the
O1, S, and N are removed by the same action.

Therefore, by performing melting in a container whose inner surface is made of a CaO-based refractory material, the chromium-based alloy of the present invention having a low zero content and a low N content can be easily obtained.

By the way, in the present invention, when melting is performed in a container whose inner surface is made of CaO-based refractory material, Au or Au
2 and Ti may be added so that the residual amounts of Au and Ti after cooling and solidification are within the range of the present invention, that is, Af 11% or less, Au 21% or less, and Ti 1% or less. In particular, by making molten calcia, excessive contamination of Ca into the molten metal can be reduced by adding An or Au2 and Ti, and the Ca content in the resulting alloy can be easily controlled within the range of the present invention. That is 20
It can be set to 0 ppm or less.

The molten alloy thus obtained is cast under a non-oxidizing atmosphere according to a conventional method.

At this time, the material of the mold used for casting is the metal mold or AJ.
12o3, ZrO2 or CaO refractory materials, etc.
Among these, CaO-based refractory materials are particularly suitable.

According to such a method, A21% or less, and in some cases T
Contains i1% or less, CCa200pp or less, 0O400pp or less, NN200pP or less, and the remainder is substantially Cr.
The chromium-based alloy for vapor deposition of the present invention can be produced extremely easily.

[Function] Since the chromium-based alloy for vapor deposition of the present invention has a low O and N content, a thin film with high characteristics can be obtained.

Furthermore, AfL contained in the chromium-based alloy for vapor deposition of the present invention
, Ca is deposited by vacuum evaporation or sputtering in an τ atmosphere as follows: 4AIt+302-2Au203 2 A JZ + N 2→2Aj2N2 Ca +
02 → 2 Ca 0 3Ca+N2=Ca3N2 Reacts as follows, lowering the gas components in the 7 atmosphere.
It has a so-called getter effect.

Similarly, Ti also exhibits a good getter effect by complementing the effects of A° C. and Ca as shown in the following equations.

Ti+0 2 →Ti02 Ti +N2 →TiN 2 Therefore, the stability and formation rate of thin film formation during vapor deposition are improved, and the obtained thin film has high purity and excellent corrosion resistance, homogeneity, and smoothness, and has excellent properties. This has been greatly improved, making it possible to manufacture high-performance thin films with high production efficiency.

[Example] Examples will be described below.

Example 1 A chromium-based alloy having the composition shown in Table 1 was used as a material for vapor deposition, and a sputtering device with a diameter of 10 cm was used with the following specifications.
A thin film was formed on a glass substrate. Note that the substrate heating temperature was 80°C.

Sputtering equipment specifications Magnetron type high frequency sputtering equipment Maximum pressure Kani IKW Ultimate vacuum: 10-'torr Target dimensions: 100mm (φ) x 5mm (t) 1st
Tables (Ca, O, N: l+I1m%; others: %) The results of examining the thickness of thin films formed with each vapor deposition material by varying the sputtering power are shown in FIGS. 1 and 2.

From FIG. 1 and FIG. 2, the chromium-based alloy for vapor deposition of the present invention is
It is recognized that there is little variation from batch to batch, the film is homogeneous, and the film formation efficiency is high.

Example 2 The surface roughness of the thin film (film thickness: approximately 1 μm) obtained in Example 1 was investigated, and the results of the roughness degree are shown in Table 2.

The surface roughness was measured using the stylus 1 type roughness measurement method, but the roughness displayed in the table was examined in terms of average roughness and maximum roughness.

*The average roughness indicates the thickness deviation (within 95%) from the average thickness.

From Table 2, it is clear that the thin films obtained using the alloys of the present invention have extremely high surface smoothness.

[Effects of the Invention] As detailed above, the chromium base metal for vapor deposition of the present invention has O
, N content is small, and the gas components in the vapor deposition atmosphere are significantly reduced due to the getter action of Ti and Ca.

Therefore, the film formation stability and film formation rate by vapor deposition are improved, and the obtained thin film has high purity, corrosion resistance,
The properties of homogeneity and smoothness are extremely high.

Therefore, according to the chromium-based alloy for vapor deposition of the present invention, a thin film with high characteristics can be obtained with high efficiency. It is extremely useful as a

[Brief explanation of the drawing]

1 and 2 are graphs showing the results obtained in Example 1, and show the relationship between the sputtering power and the film thickness obtained.

Claims (2)

[Claims] (1) Al 1% by weight or less, Ca 200ppm or less, O4
00 ppm or less, N200 ppm or less, and the balance is substantially Cr. (2) Al 1% by weight or less, Ti 1% by weight or less, Ca20
A chromium-based alloy for vapor deposition, characterized in that it contains 0 ppm or less, 400 ppm or less of O, and 200 ppm or less of N, with the remainder being substantially Cr.