JP3416999B2 - Sputtering roll target material with high strength - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention
Therefore, the present invention relates to a sputtering target material having a high strength because a fine recrystallized structure can be obtained by heat treatment after rolling. 2. Description of the Related Art Conventionally, for example, a thin film constituting an electrode or a wiring of an integrated circuit of a semiconductor device has been disclosed in, for example, JP-A-4-32.
No. 3871, the atomic% (hereinafter, referred to as
% Represents atomic%), Ta: 0.1 to 5%,
It is well known that the remainder is formed by sputtering using a casting target material composed of an Al alloy having a composition of Al and inevitable impurities. [0003] On the other hand, in recent years, the size and performance of the sputtering apparatus have been remarkably increased, and accompanying this, the target material has tended to be larger due to labor savings. For casting target materials,
Since it is a casting, the average crystal grain size is relatively 500
μm or more, and the size of the Al-Ta intermetallic compound, which is the second phase, is also 100 μm or more in average particle diameter, and does not have sufficient strength. In addition, cracking and chipping are likely to occur during operation, and it is currently impossible to use the material for practical use. In addition, there is a situation that the above-mentioned conventional cast target material is extremely difficult to be rolled. [0004] Therefore, the present inventors have proposed:
From the viewpoint as described above, focusing on the above-mentioned conventional casting target material, as a result of researching to improve the strength thereof, Al alloy constituting the above-mentioned conventional casting target material,
5-100 pp of Ca and / or Mg as alloy components
If it is contained in the proportion of m, rolling to this becomes possible,
Therefore, by performing a recrystallization heat treatment after the rolling process, the structure is refined, and the grain size of the crystal grains and the Al-Ta intermetallic compound are each reduced to an average grain size of 30 μm or less, and the oxygen content is relatively reduced. In the conventional casting target material, the oxygen content, which was usually 40 to 100 ppm, was reduced to 35 ppm or less, and as a result, a research result was obtained that high strength was obtained. The present invention has been made on the basis of the above research results, and contains 0.1 to 5% of Ta, 5 to 100 ppm of Ca and / or Mg, and the balance of Al and inevitable impurities. And a high-strength sputtering roll target material composed of an Al alloy having a recrystallized structure formed by heat treatment after rolling. Next, the reason why the component composition of the Al alloy constituting the rolling target material of the present invention is limited as described above will be described. (A) Ta The Ta component has an effect of improving the stress migration resistance (heat resistance) and corrosion resistance of a thin film formed by sputtering, but if the content is less than 0.1%, the effect is desired to be improved. No effect is obtained, while its content is 5%
, The electric resistance of the thin film suddenly increases, so the content was determined to be 0.1 to 5%. (B) Ca and Mg These components exert a strong deoxidizing effect, reduce the oxygen content to 35 ppm or less, and enable rolling free of cracks. A fine recrystallized structure is formed by heat treatment, and the grain size of the crystal grains and the Al-Ta intermetallic compound are both reduced to an average grain size of 30 μm or less, and the strength is significantly improved.
If the content is less than 100 ppm, the desired effect cannot be obtained. On the other hand, if the content exceeds 100 ppm, the electrical characteristics of the thin film deteriorates. Therefore, the content is set to 5 to 100 ppm. [0008] Next, the rolling target material of the present invention will be specifically described with reference to examples. In a vacuum melting furnace having a degree of vacuum of 1 × 10 ⁻⁴ torr or less, an aluminum alloy melt having the composition shown in Table 1 was melted and cast into an iron mold, and the plane size was 200 mm ×
The ingot is 200 mm in thickness and 40 mm in thickness.
Hot rolling, which is repeated three times,
A hot-rolled sheet having a thickness of 8 mm and subsequently subjected to a recrystallization heat treatment at 600 ° C. for 1 hour in the atmosphere to thereby obtain a hot-rolled sheet without any cracks. Target materials 1 to 3 were manufactured respectively. Also, for the purpose of comparison, the degree of vacuum was similarly set to 1 ×
In a vacuum melting furnace of 10 ⁻⁴ torr or less, an Al alloy melt having the composition shown in Table 1 is also melted and cast into an iron mold, and the dimensions of width: 315 mm × thickness: 8 mm × length: 620 mm Conventional casting target materials 1 to 3 were manufactured by using the ingots. Next, the oxygen content of each of the rolled target materials 1 to 3 of the present invention and the conventional cast target materials 1 to 3 obtained as a result is measured, and their structures are observed to determine the average crystal grain size and Al-Ta. For the purpose of measuring the average particle diameter of the intermetallic compound and further evaluating the strength, the above-mentioned various target materials were subjected to width: 300 mm × thickness: 5 mm × length:
After cutting to a large size of 600 mm, using pure In solder, it was soldered to an oxygen-free copper backing plate in the atmosphere at a temperature of 180 ° C. and a holding time of 20 minutes. Vacuum degree: 5 ml / min A while maintaining 2 × 10 ^-4 torr
Sputtering for forming a thin film on a glass substrate was performed for 300 hours in an r stream at an output of 10 kW, and the sputtering time until cracks occurred in the target material was measured. Table 1 shows the measurement times. [Table 1] From the results shown in Table 1, the rolled target materials 1 to 3 of the present invention have a relatively lower oxygen content and a smaller crystal grain than the conventionally cast target materials 1 to 3. The diameter and the particle size of the Al-Ta intermetallic compound are small, and the composition is relatively fine. As a result, the composition has a high strength. It is clear that it performs well over its lifetime. As described above, the rolling target material of the present invention has high strength in a microstructure by heat treatment after rolling, and as a result, large-scale practical use becomes possible. It greatly contributes to labor saving.

Claims (1)

(57) [Claim 1] Ta: 0.1 to 5 atomic%, Ca and / or Mg: 5 to 100 ppm,
Composition balance being Al and inevitable impurities, and the rolling pressure
A high-strength sputtering rolled target material comprising an Al alloy having a recrystallized structure formed by post-processing heat treatment .