JP3538664B2 - Coating method of Ti-based material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a method for coating a Ti-based material, and particularly to a Ti-based material capable of improving the wettability of the surface of the Ti-based material with respect to a bonding material such as an indium (hereinafter abbreviated as In) -based material. The present invention relates to a coating method.

[0002]

2. Description of the Related Art As a method for forming a thin film used in an integrated circuit, a sputtering method is known. This method includes physical sputtering (PVD) and reactive sputtering, and both methods use a sputtering target. The sputtering target is composed of a target member to be irradiated with ions and a backing plate for supporting the target member from the back. Specifically, a backing plate made of a Ti-based material has copper (hereinafter abbreviated as Cu). 2. Related Art A target member made of an aluminum (hereinafter abbreviated as Al) -based material is bonded (brazed) with an In-based material. For example, the use of a Ti-based material is described in Japanese Patent Application Laid-Open No. 6-293963, and the use of an In-based material for bonding a target member is described in the above-described Japanese Patent Application Laid-Open No. 3-140644. .

[0003]

Incidentally, the surface of the above-mentioned Ti-based material is covered with a thin and strong oxide film (passive film) due to the presence of air, moisture and the like. The passivation film is strong and extremely difficult to remove, and hardly reacts with other metals. Therefore, the wettability at the time of bonding is extremely poor. Is extremely difficult. In order to improve such difficulty, Japanese Patent Application Laid-Open No. 6-293963 discloses an attempt to spray Cu on the surface of a backing plate made of a Ti-based material, thereby improving the wettability of the In-based material. Has been made. However, performing Cu thermal spraying in this way naturally leads to a significant increase in cost of the sputtering target. In the case of a used sputtering target, a target member is removed, and a new target member is bonded to a backing plate and reused, that is, a problem similar to the above occurs when the sputtering target is recycled. Also, in JP-A-6-116706, T
As a surface treatment method for an i-based material, for example, it is proposed that a material coated with Cu powder be heated in a vacuum at 700 ° C. for about 1 hour, thereby diffusing Cu to the surface of Ti and improving the adhesion strength between the two. Have been. However, since this reaction is a solid phase reaction, the thickness of the generated reaction layer is at most several μm, and the reaction layer is fragile. Therefore, when recycling the sputtering target, it is necessary to perform the above surface treatment again.

Therefore, the inventors conducted various tests utilizing the eutectic reaction of Ti-Cu in order to improve the wettability of the Ti-based material and reduce the recycling cost of the sputtering target. First, in Test 1, Ti
An 18 μm thick Cu foil was placed on the surface of the
30 at 850 ° C lower than the eutectic temperature of Cu (887 ° C)
Heated for minutes. As a result, a reaction of Ti—Cu was observed only in a portion having an area ratio of 20%, and the remaining 80% portion remained unreacted. Therefore, according to this coating method, the object of uniformity of the coating process cannot be achieved. Next, as Test 2, a Cu foil having a thickness of 18 μm was arranged on the surface of the Ti-based material, and heating was performed at 900 ° C. higher than the eutectic temperature for 30 minutes. As a result, as shown in Table 1 and FIG. 1, α, Ti ₂ Cu layer, and TiCu layer were mixed and formed on the surface of the Ti-based material. In Test 3, a thickness of 5 mm was applied to the surface of the Ti-based material.
A 4 μm Cu foil was placed, and the same heating as above was performed.
As a result, as shown in Table 1, a Ti ₂ Cu layer was mainly formed on the surface of the Ti-based material. In Test 4,
A 100 μm thick Cu foil is placed on the surface of a Ti-based material,
The same heating as above was performed. As a result, as shown in Table 1, a TiCu layer was mainly formed on the surface of the Ti-based material. Then, for the pure Ti-based material and the co-test materials of Tests 2 to 4 shown in Table 1, that is, the Cu content was 0 to about 50 at%.
A test for evaluating the wettability between the layer and In was performed at 200 ° C. for 30 minutes, but none of the layers was wet.

[0005]

[Table 1]

As described above, in the method of forming a Cu-based coating layer utilizing the eutectic reaction of Ti-Cu, uniformity of the reaction cannot be obtained in a temperature range lower than the eutectic temperature. Homogeneous surface treatment is almost impossible.
On the other hand, if the treatment is performed in a temperature range higher than the eutectic temperature in order to obtain uniformity of the reaction, a liquid phase is rapidly generated in this temperature range and the reaction between Ti and Cu also proceeds rapidly.
The penetration of Ti into the liquid phase containing Cu becomes remarkable. Therefore, the composition of the product contains 50 at% or more of Ti,
The wettability to the bonding material cannot be ensured.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional drawbacks, and has as its object to provide a Ti-based material capable of improving the wettability during bonding using an In-based material or the like. It is an object of the present invention to provide a coating method. Further, the present invention provides a plate made of a Ti-based material having improved wettability to a bonding material as described above,
It is also an object of the present invention to provide a sputtering target whose manufacturing cost is reduced by using this as a backing plate. Another object of the present invention is to reduce the recycling cost of a sputtering target.

[0008]

Therefore, a method for coating a Ti-based material according to claim 1 is a method for coating a Ti-based material on a surface of a Ti-based material by adding Ti, Cu, Ti and a third metal other than Cu.
A Cu-based material containing a third metal as a component such that a source eutectic temperature or a liquid phase generation temperature due to another reaction is lower than a binary eutectic temperature between Ti and Cu is arranged, T and a temperature higher than the ternary eutectic temperature.
It is characterized in that an i-based material and a Cu-based material are heated, and a compound layer containing Ti, Cu, and the third metal as components is formed at the interface by a reaction between the two.

[0009] The Ti-based material used in the above is
It contains industrial pure Ti and industrial Ti alloy, and specifically, Ti-5Al-2.5Sn (the remainder is inevitable impurities and Ti in weight%, the same applies hereinafter), Ti-6Al-4Z
r-1V, Ti-8Al-1Mo-1V, Ti-8Al
-12Zr, Ti-3Al-2.5V, Ti-8Mn,
Ti-4Al-4Mn, Ti-6Al-4V, Ti-7
Al-4Mo, Ti-3Al-11Cr-13V and the like can be mentioned.

In general, the ternary eutectic temperatures of the three types of metals A, B, and C are necessarily higher than any of the binary eutectic temperatures of the metals A, B, B, and C or the metals C and A. It is cold.
Therefore, for example, Ti, Cu and S in the case where tin (hereinafter abbreviated as Sn) is used as the third metal as in claim 3
The ternary eutectic temperature of n is lower than the binary eutectic temperature of Ti and Cu. Therefore, if the Ti-based material and the Cu-based material are heated to a temperature higher than the ternary eutectic temperature and lower than the binary eutectic temperature, the reaction between Ti and Cu is prevented from proceeding rapidly. In addition, a liquid phase can be generated between the surface of the Ti-based material and the Cu-based material. The presence of such a liquid phase causes the surface tension of Ti
In addition to forming a uniform contact state between the Cu-based material and the Cu-based material, the penetration of Ti into the solution of Cu and Sn,
A solid phase diffusion reaction of a solution component, i.e., Cu or Sn, into i can be caused in a temperature range lower than the binary eutectic temperature. Accordingly, between the Ti-based material and the Cu-based material, the reaction between Ti and Cu proceeds uniformly and at a slow speed via the liquid phase. As a result, a compound layer rich in Cu can be uniformly formed on the surface of the Ti-based material, and coating with improved wettability during bonding can be performed. In order to generate a liquid phase at a temperature lower than the binary eutectic temperature of Ti and Cu, a reaction other than the eutectic reaction may be used.

The above-mentioned heating can be performed in the air, but is preferably performed in a non-oxidizing atmosphere such as a vacuum, an inert gas or a reducing gas. This is because it is possible to reliably prevent an oxide film from being formed on the surface of the Ti-based material during the heat treatment, and to perform coating with improved wettability to the bonding material.

In the above-mentioned coating method, the third metal contained in the Cu-based material may be any one as long as it forms a liquid phase by Ti, Cu and this third metal by a eutectic reaction or other reaction. . It is T as described above.
This is because the ternary eutectic temperature of Ti, Cu and the third metal is always lower than the binary eutectic temperature of i and Cu. However, as the Cu-based material, a material containing Sn as the third metal is preferably used.
It is because the ternary eutectic temperature of Ti, Cu and Sn is Ti and C
u, which is sufficiently lower than the binary eutectic temperature, and can easily control the heating temperature.
This is because the system alloy has advantages such as very good wettability with In. When a Cu-based material containing Sn is used, the heating temperature in the above-mentioned coating method is preferably set to about 700 ° C to 887 ° C. If the temperature is lower than about 700 ° C., the amount of Sn needs to be 50 wt% or more in order to generate a liquid phase between the Ti-based material and the Cu-based material. The binary eutectic temperature is 887 ° C., and if it is higher than this, it becomes difficult to form a compound layer rich in Cu as described above.

The compound layer formed by the above-mentioned coating method is mainly composed of Cu as described in claim 5, and preferably comprises about 60% by weight of Cu as defined in claim 6.
It contains above.

The C used in the above coating method
As the u-based material, for example, a material having a thickness of about 1 mm can be used. However, it is preferable to use a foil or powdered Cu-based material. This is because, in this way, in the cooling process after the heat treatment, the warpage of the material that can be caused by the difference in the thermal shrinkage between Ti and Cu can be avoided. Further, the Cu-based material may be Cu
A foil formed by plating a third metal such as Sn may be used. In this case, the plating process causes Cu
There is an advantage that the component ratio between the and the third component can be easily changed. In addition, the term "including a third metal as a component" in the first aspect means that the above-mentioned plating is included. The same applies to the case where Cu foil and Sn powder are used together.

According to the above coating method, C
Ti material made plate coated surface by a compound layer rich in u can be obtained, using this plate as a backing plate for scan sputtering target. That bonding surface Cu-based material with Ba Tsu <br/> king plate to the backing plate, In-based material,
A target member made of one or more of Sn-based material, silver (hereinafter abbreviated as Ag) -based material, and nickel (hereinafter abbreviated as Ni) -based material is bonded using an In-based material or the like. It is. In this case, since the wettability of the surface of the backing plate is improved by the coating, good bonding properties can be obtained.

In the sputtering target obtained as described above, after sputtering, the used target member is removed, and when bonding a new target member, the compound layer containing a large amount of Cu can be used. Is left behind, so that bonding using an In-based material or the like can be performed without any pretreatment.

The Ti according to any one of claims 1 to 8,
According to the method of coating a system material, a plate made of a Ti material having improved surface wettability with respect to a bonding material such as an In material can be obtained. The bonding property of the plate made of the Ti-based material is remarkably improved by the improvement of the wettability. Also, as compared with a case where a coating layer is obtained only by a solid phase reaction (for example, JP-A-6-116706)
The uniformity and strength of the coating layer are significantly improved,
It is possible to obtain sufficiently good results without practical problems. Also, the conventional thermal spraying of Cu becomes unnecessary, while
Since coating treatment can be performed using inexpensive Cu foil,
The processing cost can be greatly reduced.

Then, such a plate made of a Ti-based material is
It is used as a backing plate for scan sputtering target, because bondability very homogeneous, and is good, improvement of film quality, and may reduce the likelihood of剥雑target member.

[0019] According to the sputtering coater rodents bets, it is possible to greatly reduce recycling costs.

[0020]

EXAMPLE A 25 μm-thick Cu-20S film was formed on the surface of a Ti material.
An n (weight%) foil was placed and kept at a temperature of 800 ° C. for about 30 minutes in a vacuum atmosphere of 10 ⁻⁴ Torr.

As a result, 30 Cu5S was formed on the surface of the Ti material.
An n65Ti layer, a 10 µm 6Cu60Sn33Ti layer, and a Cu layer of about 25 µm in which 25% of Sn is dissolved as a solid solution were uniformly formed in this order from the Ti material side. That is, a compound layer rich in Cu is formed on the surface of the coating layer. Further, in the reaction of Cu and Ti alone, the compound layer was formed only in a portion having an area ratio of 15 to 20%, whereas in this example, the compound layer was formed in an area ratio of 100%. In addition, the thickness of the coating layer varied greatly from 0 to 120 μm in the reaction of Cu and Ti alone, but in this example, the uniformity was excellent at 18 to 26 μm. Further, when the wettability test with In was carried out at a temperature of 200 ° C. for 30 minutes, the untreated Ti-based material did not wet at all, whereas the specimen obtained in this example was good. Showed excellent wettability. When a shear test was performed, the shear strength of the test piece was 4 MPa. This is a sufficient strength comparable to the bonding strength of In solder when using a Cu material as a base material.

Also, 18 μm, 35 μm, 70 μm Cu
The same processing as described above was performed using a Cu-based material in which the foil was plated with Sn of 2 to 3 μm. Also in this case, similarly to the above, a Cu-rich coating layer is obtained at an area ratio of 100%, the uniformity of the thickness and the wettability with In are good, and the sufficient shear strength similar to the above is obtained. Obtained.

[Brief description of the drawings]

FIG. 1 is a micrograph showing a metal structure on a surface of a specimen obtained by reacting Cu and Ti at a temperature higher than a eutectic temperature.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-6-293963 (JP, A) JP-A-8-108267 (JP, A) JP-A-8-276281 (JP, A) JP-A-63-1988 260686 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B23K 1/00-1/20 C23C 8/00-12/02 C23C 14/34

Claims (8)

(57) [Claims] 1. Ti, Cu and Ti on the surface of a Ti-based material
And Cu containing, as a component, a third metal having a ternary eutectic temperature with a third metal other than Cu or a temperature at which a liquid phase is generated by another reaction becomes lower than a binary eutectic temperature between Ti and Cu.
A system material is disposed, the temperature is lower than the binary eutectic temperature, and 3
The Ti-based material and the Cu-based material are heated to a temperature higher than the original eutectic temperature, and Ti, C
u, a method of coating a Ti-based material, comprising forming a compound layer containing the third metal as a component. 2. The method for coating a Ti-based material according to claim 1, wherein the heating is performed in a non-oxidizing atmosphere such as a vacuum, an inert gas or a reducing gas. 3. The method according to claim 1, wherein the third metal is Sn. 4. The heating temperature is about 700 ° C. to 887 ° C.
4. The method for coating a Ti-based material according to claim 3, wherein: 5. The compound layer formed as described above comprises Cu
The method for coating a Ti-based material according to claim 4, wherein 6. The compound layer formed as described above comprises Cu
6. The method of coating a Ti-based material according to claim 5, wherein the content of Ti is 60% by weight or more. 7. The method according to claim 1, wherein the Cu-based material is a foil or a powder. 8. The method of coating a Ti-based material according to claim 1, wherein the Cu-based material is obtained by plating a Cu foil with a third metal.