JPS61124566A - Production of al-si alloy target plate material for sputtering - Google Patents

Abstract

PURPOSE:To produce an excellent target material to be used in the stage of forming a circuit wiring, etc. of a semiconductor device by subjecting a circular cylindrical casting consisting of an Al-Si alloy to upset-forging or further extrusion working in the longitudinal direction thereby forming the same into a plate material. CONSTITUTION:The Al-Si alloy contg. 0.5-2wt% Si is vacuum-melted and is forged to a circular columnar ingot having <200mm diameter. Such ingot is subjected to solid forging or to extrusion molding at >=3/2 in working ratio with respect to the longitudinal direction according to need and thereafter the ingot is cut or machined to a prescribed length to form a blank chip material. The blank chip material is subjected to upset forging at 1/10-1/2 upset forging ratio in the longitudinal direction and further to rolling according to need by which an Al-Si alloy target plate material for sputtering is manufactured. The concn. of Si in the target is uniform in the plane direction and thickness direction and the thin Al-Si film having the uniform concn. of Si is formed by using such target.

Description

Detailed Description of the Invention [Field of Industrial Application] This invention #4 is characterized in that fine crystallized St is distributed axially symmetrically in the radial direction and uniformly distributed in the thickness direction. #P21+ such as transistors, IC1, and LSI!
A suitable for use as a target when forming circuit wiring directly in the body by sputtering.
The present invention relates to a method for manufacturing a Z-SI metal target plate material.

[Conventional technology]

Generally, Al-Si containing Si: 0.5 to 21
It is well known that thread alloy is used as a target plate material when forming circuit wiring of the above-mentioned semiconductor device by sputtering method.

Conventionally, the Al-Si alloy target plate material for woodcutting is made by vacuum melting, bath cracking, and then casting the bath water into a square ingot, which is then subjected to pressure processing and forging to form a plate material. It is manufactured by stretching and cutting out target plate material.

[Problem that the invention seeks to solve]

However, in the Al-Si alloy target plate material for sputtering manufactured by this conventional method, coarse primary Si crystals crystallize during casting, and this primary crystal 3i segregates in the center of the square ingot, and this tendency This becomes more noticeable as the ingot becomes larger, and it is impossible to completely dissolve this primary Si into the matrix by heat treatment, and furthermore, it is difficult to roll or forge an ingot along its length. Because it is a sheet material that is stretched,
It is impossible to avoid uneven distribution of 51 ml in the plane direction and thickness direction of the target plate material, and furthermore, even if the target plate material obtained as a result is subjected to heat treatment, the primary crystal S
Since it is impossible to mira-dissolve precipitated Si, which is finer than t but still larger than precipitated St, it is also impossible to eliminate the 5iI11 degree non-uniformity by heat treatment.

Such a non-uniform Al-Si based solid metal target material with a 5ill11 degree distribution is used as the Ig1wI of the above semiconductor device.
When used to form glands, etc., Si in the sputtered film
It affects the distribution and destabilizes the semiconductor properties, and also causes abnormal arc emissions during sputtering operations, causing a decrease in yield9. there were.

[Means for solving problems]

Therefore, the present inventors determined that 5iI
7) Sputtering method that can be stably formed on a sputtering film with a uniform defined distribution As a result of research to manufacture an Al-Si alloy target plate material, we found that (a) the ingot to be cast is cylindrical; And if its maximum diameter is 200 earthquakes, s in the ingot
The ia degree distribution is axially symmetrical in the radial direction and uniform in the longitudinal direction.

(2) The above (2) cylindrical ingot) 1-Cut or cut in the length direction to obtain a chip material, and when this chip material is forged and formed into a plate material, relatively coarse primary crystals of Sl are produced. In addition to making the Si in the plate material uniform in the surface direction and thickness direction, the Si content in the sputtering method using this as a target is also made uniform.

(e) When the plate material formed and shaped by swaging forging of Φ above is further successively rolled, primary crystal S1
Not only the miniaturization of the thickness and the uniformity of stmy are further promoted, but also the thickness accuracy is improved and the yield is further improved.

(b) Furthermore, the refinement of the primary Si crystals in the plate material formed by swaging forging (2) above (4) can be further promoted by subjecting the cylindrical ingot to physical forging or extrusion processing prior to swaging forging. to become

The findings shown in (a) to (d) above were obtained.

This invention was made based on the above knowledge, and after melting A6 sogan containing Si: 0.5 to 2] [lid%], it was made into a cylindrical ingot with a diameter of 200 pieces. Then, if necessary, the cylindrical ingot is subjected to solid forging or extrusion processing 1 with a processing ratio of 3/2 or more in the longitudinal direction, and then cut or cut to a predetermined length to obtain a chip material. , Subsequently, this chip material is subjected to swaging forging with a swaging casting ratio of 1/10 to 1/2 in the longitudinal direction, and further rolled as necessary to form a plate material, which is then sputtered. The method for producing the Al--Si filament target plate material has some features.

Next, the reason why the swaging forging ratio and processing ratio are limited as described above in the method of the present invention will be explained.

(a) Swaging-9-Forging Ratio As mentioned above, this swaging forging refines the primary Si crystals and makes the Si ambiguity distribution uniform in both the bending direction and the cutting direction of the target plate material. However, if the ratio is less than 1/2 in the longitudinal direction, swaging forging is insufficient and the desired refinement and uniformity cannot be achieved. When you cross it,
If the machining becomes too difficult, not only will buckling and cracking occur in the target plate material, but also the friction with the machining tool will increase and high machining stress will be required. 1/2 to 1/1 in proportion to the longitudinal direction
It was set as 0.

Φ) If the cylindrical ingob h is stretched in the longitudinal direction by solid forging or extrusion prior to swaging forging,
This solid forging or extrusion processing is applied as necessary because the single-output Si in the target becomes even finer, but if the processing ratio is less than 3/2 in the longitudinal direction, the desired fineness cannot be obtained. Since the effect of improving the thickness cannot be obtained, the machining ratio [, 3 in the ratio to the longitudinal direction]
It is set as 72 or above.

〔Example〕

Next, the method of the present invention will be specifically explained using examples.

Using a normal vacuum melting furnace, the pressure crab is 1X10''torr.
In the following vacuum, Al-Si based molten metals having the component compositions shown in Table 1 were prepared.
The ingot is cast into a cylindrical ingot with the dimensions shown in the table, the upper and lower ends of this ingot are completely cut and removed, and then the ingot is selectively forged or extruded under the conditions shown in Table 1. [Loe is applied, and subsequently, these ingots are cut into two pieces, and the entire chip material with the dimensions shown in Table 1 is also cut out. Using this chip material,
Similarly, under the conditions shown in Table 1, swage forging was performed, and further rolling was selectively performed at ThL to form a plate material with a final thickness of 12 mm. Methods 1 to 21 of the present invention were carried out by cutting out target plate materials.

In addition, for the purpose of comparison, three types of Al-5i-based gold baths having the same composition as in the above example were used at a concentration of 150
After casting into a rectangular ingot with dimensions of m x bank width: 50 m x length: 230 + w, the upper and lower ends were cut and removed, and the ingot was rolled to 225 m under normal cold rolling conditions. After smooth rolling, it is cold rolled into a plate with a thickness of 12mm, and finally, this plate is rolled into a plate with a diameter of 200s.
+X Thickness: Conventional methods 1 to 3 (fc) were obtained by cutting out targets with dimensions of 12 scales, and the ingot composition was the same as that of conventional methods 1 to 1 to 7 of the present invention, and conventional method 2 was the same as that of the present invention methods 1 to 7. Same as methods 8 to 14, and conventional method 3 to methods 15 to 2 of the present invention
1) was performed.

Next, target plate materials obtained by the above-mentioned uninvented methods 1 to 21 (hereinafter referred to as present invention target plates 1 to 21) and target plate materials obtained by the above conventional methods 1 to 3 (hereinafter referred to as conventional target plates @ 1 to 21) were prepared. 3), as shown in the partially cutaway perspective view in FIG.

Direction, this and 90' (1st place 几. Regarding the direction,
Center ro and surrounding fi6r6. Measure the St content at 9 points above M and the middle part of these equally spaced areas: r, 1 irl+, and in the thickness direction, measure the St content at 9 evenly spaced 5 points in the thickness direction at the midpoint between the center and the peripheral part of the target. Location: t
1°tl+tl+t4+ and t, St combination t1! :
Each was measured. The results of these measurements are shown in Table 2.

〔Effect of the invention〕

From the results shown in Table 71jI & 2, the Si acidity of the target plates 1 to 21 of the present invention is almost uniform in the surface direction and the thickness direction, whereas in the conventional target plates 1 to 3, the Si acidity is uniform in the planar direction and the thickness direction. It is clearly seen that the sin degree is non-uniform in both the thickness direction.

Next, using the target plates 1 to 21 of the present invention and the conventional target plates 1 to 3, vacuum degree: 3 x 10''t
orr.

Voltage: 250V, '1st class: 5 A.

Sputtering was performed under the following conditions to form a thin film with a diameter of 200 m and a thickness of 1 pm on the surface of a substrate made of Si.

Furthermore, the St content in these intermediate parts was measured.

The measurement results are also shown in Table 3.

As shown in Table ig3, the target plate materials 1 to 1 of the present invention
It can be seen that when using No. 21, a thin film with uniform Si acidity can be formed by sputtering, whereas in the case of conventional target plates 1 to 3, the Si acidity in the thin film is non-uniform.

As mentioned above, according to the method of the present invention, fine crystallization of S
Al-Si with uniform distribution of t in the surface direction and thickness direction
It is possible to fabricate a target soft plate material made of the alloy, and by using this target plate material, industrially useful effects such as the ability to stably form a sputtered thin film with a uniform Si acidity can be obtained.

Table 3

[Brief explanation of drawings]

Figure 1 is a partially cutaway perspective view of the target plate material.
It is a diagram showing content measurement points.

Claims (4)

[Claims] (1) After vacuum melting an Al alloy containing 0.5 to 2% by weight of Si, it is cast into a cylindrical ingot with a diameter of 200 mm or less, and then this cylindrical ingot is cut or cut into a predetermined length. A chip material is obtained by forming the chip material into a plate material by subjecting the chip material to swaging forging at a swaging forging ratio of 1/10 to 1/2 in the longitudinal direction to form a plate material.
A method for manufacturing a Si-based alloy target plate material. (2) After vacuum melting an Al alloy containing 0.5 to 2% by weight of Si, it is cast into a cylindrical ingot with a diameter of 200 mm or less, and then this cylindrical ingot is processed at a processing ratio of 3 in the longitudinal direction. After performing solid forging or extrusion processing of /2 or more, cut or cut to a predetermined length to obtain a chip material, and then apply a swag forging ratio of 1/10 to 1 in the longitudinal direction to this chip material. Plate-shaped material A for sputtering, characterized in that it is formed into a plate material through swaging forging of /2.
A method for manufacturing l-Si alloy target plate material. (3) After vacuum melting an Al alloy containing 0.5 to 2% by weight of Si, it is cast into a cylindrical ingot with a diameter of 200 mm or less, and then this cylindrical ingot is cut or cut into a predetermined length. This chip material is then subjected to swaging forging with a swaging forging ratio of 1/10 to 1/2 in the longitudinal direction, and is further rolled to be formed into a plate material. A method for manufacturing an Al-Si alloy target plate material for sputtering. (4) After vacuum melting an Al alloy containing 0.5 to 2% by weight of Si, it is cast into a cylindrical ingot with a diameter of 200 mm or less, and then this cylindrical ingot is processed at a processing ratio of 3 in the longitudinal direction. After performing solid forging or extrusion processing of /2 or more, cut or cut to a predetermined length to obtain a chip material, and then apply a swag forging ratio of 1/10 to 1 in the longitudinal direction to this chip material. 1. A method for producing an Al-Si alloy target plate material for sputtering, characterized by performing swaging forging of /2 and further rolling to form a plate material.