JPH0874044A - Cobalt silicide sintered target material for sputtering hardly generating particles during film formation - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a Co silicide sintered target material for sputtering, which causes less particles during film formation. [Configuration] sputtering Co silicide grilled Yuita - Get material, CoSi _n (where, n is in a molar ratio 2.0
2.5), and the CoSi ₂ compound shown in the Co—Si _binary alloy phase diagram is present as a reaction product phase, and in the CoSi ₂ reaction product phase, CoSi ₂ − in the phase diagram It has a structure in which an unreacted eutectic phase of Si eutectic is dispersed and distributed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention, when used to form a Co silicide thin film which constitutes an electrode or wiring in a semiconductor device by sputtering, causes the generation of particles which become thin film defects during film formation. It relates to significantly less sintered target material.

[0002]

2. Description of the Related Art Conventionally, when manufacturing a semiconductor device,
A Co silicide thin film having a low resistance may be formed by sputtering, and a Co silicide sintered target material is used for this. In addition, the above Co
The silicide sintered target material uses a Co plate material and a Si lump material as raw materials, and weighs them at a predetermined ratio and dissolves them by electron beam melting or the like in a non-oxidizing atmosphere.
It is also known to be manufactured by crushing and hot pressing. Furthermore, the resulting Co silicide sintered Yuita - target material, the composition formula: If CoSi _n (n is the 2.0 to 2.5 by molar ratio) is satisfied, i.e. the composition of CoSi _2.0-2.5 as a raw material It is also known that, when hot-pressed using a pulverized powder having No. 1, a two-phase structure of CoSi ₂ compound and Si in a Co—Si _binary alloy phase diagram is obtained.

[0003]

On the other hand, the progress of sputtering technology in recent years has been remarkable, and it has become possible to increase the output and size of a sputtering apparatus.
Even when forming a silicide thin film, there is a tendency for film formation to be speeded up and to have a large area. However, in the above conventional Co silicide sintered target material, this is used to form a high speed film and a large area. When the film is formed, there is a problem that particles (fine particles) are easily generated during the film formation. If a large number of particles are present in the thin film, this may cause, for example, disconnection of electrodes formed with a line width of 0.5 to 4 μm or short circuit in the wiring, thus increasing the defect rate. It will be like this.

[0004]

Therefore, the present inventors have
From the above viewpoints, when the Co silicide thin film was formed by sputtering, research was conducted to develop a Co silicide sintered target material that generates less particles, and as a result, a Co plate material and Si A lump material was weighed in a predetermined ratio, dissolved by, for example, electron beam melting, and prepared by pulverizing Co-
CoSi compound and CoS in Si binary alloy phase diagram
and CoSi-CoSi ₂ eutectic powder made of eutectic i ₂ compounds, using CoSi ₂ -Si eutectic powder made of eutectic CoSi ₂ compound and Si in same the state diagram, the ratio of these two raw material powders of predetermined When a Co silicide sintered target material satisfying the composition formula: CoSi ₂ (where n is a molar ratio of 2.0 to 2.5) is manufactured by blending with, mixing with, and hot pressing. During hot pressing,
The CoSi—CoSi ₂ eutectic powder and the CoSi ₂ —Si eutectic powder react with each other to form a CoSi ₂ compound between them, so that the resulting Co silicide sintering target is obtained. The material has a structure in which the unreacted CoSi ₂ -Si eutectic phase is distributed and distributed in the reaction product phase of the CiSi ₂ compound.
In the o-silicide sintered target material, the research results were obtained that the generation of particles during film formation is significantly reduced, and a Co silicide thin film with extremely few particles can be formed.

[0005] The present invention shall apply was made based on the above findings, CoSi _n (where, n is the molar ratio 2.0 to 2.5) satisfy the composition formula, and Co-S
The CoSi ₂ compound shown in the i _binary alloy system phase diagram exists as a reaction product phase, and in this CoSi ₂ compound reaction product phase, an unreacted eutectic phase composed of a eutectic of the CoSi ₂ compound and Si in the same phase diagram is present. It is characterized by a Co silicide sintered target material for sputtering having a distributed structure. In addition, the value of n in the composition formula is set to 2.0 to 2.5, because it is difficult to form the above-described structure when the value of n is less than 2.0, and the negative n value is 2.5.
This is because it is impossible to form a Co silicide thin film having a desired low resistance when the value exceeds the range.

[0006]

EXAMPLES Next, the Co silicide sintering type of the present invention was used.
The get material will be specifically described by way of examples. First, 5
N (nine) high-purity Co plate material and 7N high-purity Si lump material were used, these were weighed at a predetermined ratio, and the degree of vacuum was 10 −.
In an atmosphere of 5 torr, an electron beam was melted with a water-cooled copper hearth, and then coarsely crushed with a jaw crusher,
Further finely pulverized with a ball mill to obtain Co-Si
CoSi compound and CoSi ₂ in binary alloy system phase diagram
A CoSi-CoSi ₂ eutectic powder composed of a eutectic of a compound and a CoSi ₂ -Si eutectic powder composed of a CoSi ₂ compound and a eutectic of Si in the same phase diagram were prepared, and then both these eutectic powders were used as raw material powders. Used as 20-100
Table 1 with the average particle size adjusted within the range of μm
After mixing for 30 minutes in a V-type mixer, the mixture was mixed in the proportions shown in Table 1, and then hot-pressed under the conditions of temperature: 1250 ° C., pressure: 20 MPa, holding time: 60 minutes to prepare a composition formula: _n of CoSin. The values have the values shown in Table 1, and both are in the CoSi ₂ compound reaction production phase,
The Co silicide sintered target material of the present invention (hereinafter, referred to as the present invention) having a structure in which an unreacted eutectic phase of CoSi ₂ -Si eutectic is dispersedly distributed and further having a diameter of 250 mm and a thickness of 10 mm. The target materials 1 to 6 were manufactured.

For the purpose of comparison, the composition formula: CoS was changed by changing the weighing ratios of the high-purity Co plate material and the high-purity Si lump material.
A CoSi _n powder having a value of _n of i _n shown in Table 2 was prepared,
Conventional C under the same conditions except that this is used as raw material powder
o Silicide sintered target materials (hereinafter referred to as conventional target materials) 1 to 5 were manufactured. Each of the conventional target materials 1 to 5 has a structure composed of a CoSi ₂ phase and a Si phase.

Next, various target materials obtained as a result were incorporated into a sputtering apparatus, and a substrate: a Si wafer having a diameter of 152 mm, a substrate temperature: 160 ° C., a distance between the substrate and the target material: 40 mm, an atmosphere: 5 × 10-3 torr Ar gas DC output: 2.3 kW Sputtering time: 0.5 minutes A Co silicide thin film was formed on the surface of the Si wafer, and the diameter of the thin film on the Si wafer surface was 0.3 μm or more. The number of occurrences was measured. The measurement results are shown in Tables 1 and 2, respectively.

[0009]

[Table 1]

[0010]

[Table 2]

[0011]

From the results shown in Tables 1 and 2, CoSi
_The target materials 1 to 6 of the present invention having a structure in which the unreacted eutectic phase of CoSi ₂ —Si eutectic is dispersedly distributed in the ₂ reaction-produced phase.
It is apparent that the Co silicide thin film formed in 1) has significantly less particles than the thin films formed using the conventional target materials 1 to 6 having the structure of the CoSi ₂ phase. . As described above, in the Co silicide sintered target material for sputtering of the present invention, the generation of particles during film formation is extremely small, which means that the film formation area is increased even if the film formation speed is increased. Since it does not change, it is possible to satisfactorily deal with the increase in output and the increase in size of the sputtering apparatus.

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[Procedure amendment]

[Submission date] November 11, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

[0004]

Therefore, the present inventors have
From the above viewpoints, when the Co silicide thin film was formed by sputtering, research was conducted to develop a Co silicide sintered target material that generates less particles, and as a result, a Co plate material and Si A lump material was weighed in a predetermined ratio, dissolved by, for example, electron beam melting, and prepared by pulverizing Co-
CoSi compound and CoS in Si binary alloy phase diagram
and CoSi-CoSi ₂ eutectic powder made of eutectic i ₂ compounds, using CoSi ₂ -Si eutectic powder made of eutectic CoSi ₂ compound and Si in same the state diagram, the ratio of these two raw material powders of predetermined after blended, and mixed in the composition formula by hot pressing: CoSi _n (where, n is 2.0 to 2.5 molar ratio) Co silicide sintered Yuita satisfying - when producing the target material, the During hot pressing,
The CoSi—CoSi ₂ eutectic powder and the CoSi ₂ —Si eutectic powder react with each other to form a CoSi ₂ compound between them, so that the resulting Co silicide sintering target is obtained. The material has a structure in which the unreacted CoSi ₂ -Si eutectic phase is distributed and distributed in the reaction product phase of the CiSi ₂ compound.
In the o-silicide sintered target material, the research results were obtained that the generation of particles during film formation is significantly reduced, and a Co silicide thin film with extremely few particles can be formed.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H01L 21/203 S 9545-4M

Claims (1)

[Claims] 1. CoSi _n (where n is a molar ratio of 2.
0 to 2.5), and the CoSi ₂ compound shown in the Co—Si binary alloy phase diagram is present as a reaction product phase, and in this CoSi ₂ compound reaction product phase, A Co silicide sintered target material for sputtering with little particle generation during film formation, which has a structure in which an unreacted eutectic phase composed of a CoSi ₂ compound and Si is dispersed.