JP2002294438A - Copper alloy sputtering target - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copper alloy sputtering target of which the crystal grains grow little in jointing the target and a backing plate with a hot isostatic pressing method. SOLUTION: The copper alloy sputtering target has a composition comprising one or more sort of La, Mg, Li, Si, V, Zr, Hf, and Nb of 0.005-0.5 mass% in total, 0.1-5 ppm oxygen, and the balance Fe and unavoidable impurities. The copper alloy sputtering target with the backing plate includes jointing the above sputtering target with the backing plate by a hot isostatic pressing method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper alloy sputtering target, and more particularly to a copper alloy sputtering target having small crystal grain growth when a target and a backing plate are joined by hot isostatic pressing.

[0002]

2. Description of the Related Art Generally, as wiring of a semiconductor device,
It is known to use a thin-film wiring formed by sputtering, and this thin-film wiring is attached to a sputtering apparatus by attaching a high-purity copper target having a purity of 99.9999 mass% or more brazed to a backing plate,
It is known to form by performing sputtering.

It is said that the finer the crystal grains of the high-purity copper target, the smaller the generation of particles and the more uniform a thin film can be obtained. In the manufacturing process, rapid solidification, repetition of heating and forging, and a manufacturing method by powder metallurgy have been proposed.

[0004]

In recent years, there has been a demand for further cost reduction by improving the film forming speed of thin film wiring of a semiconductor device. For this purpose, sputtering with higher power has been performed. When the sputtering with high power is performed, the target is excessively heated, and the brazing material formed between the target and the backing plate is melted and melted out, and a part of the brazing material evaporates to contaminate the sputtering thin film. Sometimes. In order to avoid this, in recent years, bonding has been performed by hot isostatic pressing in a state where a high-purity copper target and a backing plate made of pure copper or pure aluminum are stacked. However, even if a high-purity copper target with fine crystal grains is manufactured by the above-described method, hot isostatic pressing with a high-purity copper target with fine crystal grains stacked on a backing plate is performed. The crystal grains of the high-purity copper target grow and grow in the inside, and when sputtering is performed using the high-purity copper target having the coarsened crystal grains, the generation of particles increases as described above, and the particles are further formed. This is not preferable because the thickness of the thin film becomes uneven.

[0005]

Means for Solving the Problems Accordingly, the present inventors have
Research was conducted to obtain a high-purity copper target without crystal grains growing and coarsening during hot isostatic pressing.
As a result, high purity copper with purity: 99.9999% or more,
A component obtained by adding at least one of La, Mg, Li, Si, V, Zr, Hf, and Nb in a total amount of 0.005 to 0.5% by mass and further adjusting the oxygen content to 0.1 to 5 ppm. Even if the copper alloy sputtering target of the composition is joined to the backing plate by hot isostatic pressing,
The growth of crystal grains by hot isostatic pressing can be small and a fine structure can be maintained, and the sputtering thin film obtained by using this copper alloy sputtering target can be formed by sputtering using a conventional high-purity copper target. There is no difference in electrical characteristics compared to thin films,
On the contrary, the research result that the corrosion resistance is excellent was obtained.

The present invention has been made based on the above research results, and (1) La, Mg, Li, Si,
At least one of V, Zr, Hf and Nb is 0.00
A copper alloy sputtering target comprising a copper alloy having a composition of 5 to 0.5% by mass, oxygen: 0.1 to 5 ppm, and the balance being Cu and unavoidable impurities;
(2) La, Mg, Li, Si, V, Zr, Hf, Nb
A sputtering target comprising a copper alloy containing a total of 0.005 to 0.5% by mass, oxygen: 0.1 to 5 ppm, and a balance of Cu and inevitable impurities, and a backing. The present invention is characterized by a copper alloy sputtering target with a backing plate formed by joining plates by hot isostatic pressing.

A thin film obtained by sputtering using the target described in the above (1) or (2) has excellent corrosion resistance and is excellent as a wiring of a semiconductor device. Therefore, the present invention is characterized by (3) a thin film obtained by sputtering using the target described in the above (1) or (2).

[0008] In order to produce the copper alloy sputtering target of the present invention, high-purity electrolytic copper having a purity of 99.9999% or more is melted in a high-purity graphite mold in an inert gas atmosphere by high-frequency melting. It can be obtained by adjusting the amount and the amount of oxygen, quenching and solidifying the melt obtained by adjusting the components in such a manner, repeating cold rolling and annealing, and finally performing strain relief annealing. The copper alloy sputtering target thus obtained is placed on a pure copper or pure aluminum backing plate, and the target and the backing plate are joined by hot isostatic pressing. At this time, the hot isostatic pressing is performed at a temperature of 500 to 550 ° C.
Pressure: 140 to 150 MPa.

Next, the reasons for limiting the component composition in the copper alloy sputtering target of the present invention will be described. (A) La, Mg, Li, Si, V, Zr, Hf, Nb When these components are contained in a small amount, they have an effect of suppressing the growth of crystal grains of the copper alloy sputtering target, but La, Mg, Li, Si , V, Zr, Hf, and Nb, the desired effect cannot be obtained if the total content is less than 0.005% by mass, while if the content exceeds 0.5% by mass, the hot isostatic pressure is increased. Even if the growth of crystal grains during pressing can be suppressed, it is not preferable for use as wiring of a semiconductor device because the resistance of the obtained sputtering thin film is increased. Therefore, La, Mg, Li, Si, contained in the copper alloy sputtering target of the present invention.
At least one of V, Zr, Hf and Nb is 0.00
It was set to 5 to 0.5% by mass (more preferably 0.01 to 0.3% by mass).

(B) Oxygen Oxygen has a function of suppressing the growth of crystal grains of a copper alloy sputtering target, and contains a small amount to improve the corrosion resistance of a thin film obtained by sputtering. It is necessary to contain 1 ppm or more, but if it exceeds 5 ppm, the corrosion resistance is rather lowered, which is not preferable. Therefore, oxygen contained in the copper alloy sputtering target of the present invention was set to 0.1 to 5 ppm.

[0011]

Next, the copper alloy sputtering target of the present invention will be specifically described with reference to examples. Purity: Prepare 99.9999 mass% high purity electrolytic copper,
This high-purity electrolytic copper was subjected to high-frequency melting in a high-purity graphite mold in an Ar gas atmosphere to adjust the oxygen content.
After adding g, Li, Si, V, Zr, Hf, and Nb to adjust the components, casting the mixture in a cooled carbon mold, repeating cold rolling and annealing, and finally performing strain relief annealing to obtain Lathe processing of the surface of the rolled body obtained, outer diameter: 300
mm × thickness: 5 mm, and the present invention copper alloy sputtering targets (hereinafter referred to as the present target) 1 to 14 and the comparative copper alloy sputtering targets (hereinafter referred to as comparative examples) having the component compositions shown in Tables 1 and 2. 1 to 9). Further, a conventional copper alloy sputtering target (hereinafter, referred to as a conventional target) was produced without adding an element to high-purity electrolytic copper. These targets were cut, and the average crystal grain size at the cut surface was measured. The results are shown in Tables 1 and 2 as the average crystal grain size (A) before hot isostatic pressing (hereinafter referred to as HIP).

Further, a backing plate made of pure aluminum was prepared, and the targets 1 to 14 of the present invention and the comparative target 1 were placed on the backing plate made of pure aluminum.
-9 and a conventional target, temperature: 500
The targets 1 to 14 of the present invention, the comparative targets 1 to 9 and the conventional target were bonded to a pure aluminum backing plate by performing HIP at 150 ° C. and a pressure of 150 MPa to produce a target with a backing plate. The obtained target with a backing plate was cut, and the average crystal grain in the cross section of the target was measured. The result is shown in Tables 1 and 2 as the average crystal grain size (B) after HIP. Further, the ratio of the average crystal grain size (A) to (B): (B) / (A) was determined as the grain growth ratio, and the results are shown in Tables 1 and 2.

Using a target having a backing plate obtained by HIP bonding the targets 1 to 14 of the present invention, comparative targets 1 to 9 and a conventional target to a backing plate made of pure aluminum, power source: AC system, power: 4 KW, atmosphere gas The composition: Ar, the sputtering gas pressure: 1 Pa, the distance between the target and the substrate: 80 mm, the sputtering time: 5 minutes.
100 linear thin films having dimensions of thickness: 2 μm and width: 100 μm were formed in parallel stripes.

The obtained 100 linear thin films are heated at 50 ° C.
Immersed in NH ₄ Cl: 1% aqueous solution held for 30 minutes,
A conduction test was conducted by supplying current to both ends of the 100 linear thin films, and the number of conducting linear thin films was measured.
2, the corrosion resistance of the thin film was evaluated.

[0015]

[Table 1]

[0016]

[Table 2]

From the results shown in Tables 1 and 2, the targets obtained by bonding the targets 1 to 14 of the present invention to the backing plate by HIP have a larger grain growth than the conventional targets bonded to the backing plate by hot isostatic pressing. From the place where the ratio is small, the growth of crystal grains is small, and furthermore, the conduction number of the linear thin film formed using the targets 1 to 14 of the present invention is larger than the conduction number of the linear thin film formed using the conventional target. It can be seen that the thin films formed using the targets 1 to 14 of the present invention have better corrosion resistance than the thin films formed using the conventional targets. However, the comparative targets 1 to 9 having compositions deviating from the conditions of the present invention may exhibit unfavorable characteristics such as a high grain growth ratio due to HIP, or poor corrosion resistance due to a small number of conducting linear thin films. I understand.

[0018]

According to the target of the present invention, it is possible to improve the film formation speed by performing high-power sputtering as compared with the conventional target, and to provide a thin film having excellent corrosion resistance. Is played.

Claims (3)

[Claims] 1. La, Mg, Li, Si, V, Zr, H
f, Nb, at least 0.005 to 0.5% by mass, oxygen: 0.1 to 5 ppm, and the balance C
A copper alloy sputtering target comprising a copper alloy having a composition comprising u and unavoidable impurities. 2. La, Mg, Li, Si, V, Zr, H
f, Nb, at least 0.005 to 0.5% by mass, oxygen: 0.1 to 5 ppm, and the balance C
A copper alloy sputtering target with a backing plate, wherein a sputtering target made of a copper alloy having a composition consisting of u and an unavoidable impurity and a backing plate are joined by hot isostatic pressing. 3. A thin film having excellent corrosion resistance, formed using the target according to claim 1.