WO2018173517A1

WO2018173517A1 - Sputtering target and production method therefor

Info

Publication number: WO2018173517A1
Application number: PCT/JP2018/003909
Authority: WO
Inventors: 宏成占部; 池田　真; 禎一郎梅澤; 真理子内田; 功河角; アン・チョオ・ブン
Original assignee: 三井金属鉱業株式会社; Hoya株式会社; ホーヤエレクトロニクスシンガポールプライベートリミテッド
Priority date: 2017-03-23
Filing date: 2018-02-06
Publication date: 2018-09-27
Also published as: JP7060578B2; JPWO2018173517A1; CN110392747B; SG11201907100RA; CN110392747A; MY193691A

Abstract

This sputtering target has a molybdenum content of 3 mol% to 25 mol% and a silicon content of 75 mol% to 97 mol%. The sputtering target comprises a silicon phase in which the average particle diameter of the silicon particles is 2.0 µm or less and a molybdenum silicide phase in which the average particle diameter of the molybdenum silicide particles is 2.5 µm or less. The average number of holes with a major axis of at least 0.3 µm that are present in the silicon phase is no more than 10 in a 90 µm x 125 µm area.

Description

Sputtering target and manufacturing method thereof

The present invention relates to a sputtering target and a manufacturing method thereof.

In a Mo—Si-based sputtering target used for mask blanks and the like, a target material obtained by sintering MoSi ₂ powder by hot pressing (hereinafter also referred to as “HP”) has been used. In manufacturing the MoSi ₂ target material sintered with HP, sintering at a high temperature is necessary, and as a result, the crystal grain size of Si after sintering tends to be large. An increase in the crystal grain size of Si contributes to an increase in generation of particles during sputtering.

For the purpose of reducing the generation of particles during sputtering, in Patent Document 1, the density is 99% or more, and the abundance of a coarse silicon phase of 10 μm or more appearing on the sputtering surface is 1 piece / mm ² or less, A silicide target for sputtering having an oxygen content of 150 ppm or less has been proposed. Patent Document 2 describes a sputtering target in which silicon is 70 to 97% by weight and the balance is substantially made of refractory metal silicide. The metal structure of the target has at least a silicon phase and a refractory metal silicide phase composed of silicon and a refractory metal, and the sputtering surface has a peak of the Si (111) surface obtained by X-ray diffraction. The half width is 0.5 deg or less, and the half width of the peak of the refractory metal silicide (101) plane is 0.5 deg or less.

Patent Document 3 describes a sputtering target for forming a light semi-transmissive film on a light-transmitting substrate. This target is substantially composed of metal and silicon, and exists as metal silicide particles and silicon particles by containing more silicon than the stoichiometrically stable composition of metal and silicon. . The average particle size and / or particle size distribution of the metal silicide particles is set so that the defect occurrence rate of the light semi-transmissive film is not more than a predetermined value.

Patent Document 4 describes a sputtering target made of a metal silicide and silicon, which is used when a mask blank is manufactured by a sputtering method. According to this document, the generation of particles is reduced according to this target.

US Pat. No. 5,460,793 JP 2002-173765 A Japanese Patent Laid-Open No. 2005-200688 JP 2004-109317 A

As described above, various attempts have been made to reduce the number of particles generated when sputtering is performed using a Mo—Si sputtering target. However, in the present situation where the characteristics of the particles required for the mask blank are becoming more and more severe, a sputtering target capable of reducing the generation of particles to a satisfactory level has not been provided.

Therefore, an object of the present invention is to improve a sputtering target, and more specifically, to provide a sputtering target in which generation of particles during sputtering is suppressed as compared with the conventional method and a method for manufacturing the sputtering target.

The present invention is a sputtering target having a molybdenum content of 3 mol% to 25 mol% and a silicon content of 75 mol% to 97 mol%,
A silicon phase having an average particle diameter of 2.0 μm or less and a molybdenum silicide phase having an average particle diameter of molybdenum silicide particles of 2.5 μm or less;
The present invention provides a sputtering target in which the average number of pores having a major axis of 0.3 μm or more present in the silicon phase is 10 or less in the range of 90 μm × 125 μm.

Moreover, this invention is as a suitable manufacturing method of the said sputtering target,
Mixing molybdenum powder and silicon powder,
The obtained mixed powder is subjected to a discharge plasma sintering method, and then subjected to a hot isostatic pressing method,
The present invention provides a method for producing a sputtering target, wherein the sintering temperature in the step of applying the hot isostatic pressing method is 1150 ° C. or higher and 1350 ° C. or lower.

FIG. 1 is a schematic diagram showing the measurement position of the long diameter of holes generated in a sputtering target.

Hereinafter, the present invention will be described based on preferred embodiments thereof. The sputtering target of the present invention includes silicon and molybdenum. Specifically, in the sputtering target of the present invention, the molybdenum content is preferably 3 mol% or more and 25 mol% or less, more preferably 3.3 mol% or more and 24 mol% or less, and 3.5 mol% or more and 23 mol% or less. It is more preferable that The silicon content is preferably 75 mol% or more and 97 mol% or less, more preferably 76 mol% or more and 96.7 mol% or less, and further preferably 77 mol% or more and 96.5 mol% or less. The sputtering target of the present invention includes a phase composed of silicon (hereinafter also referred to as “silicon phase”) and a phase composed of molybdenum silicide (hereinafter also referred to as “molybdenum silicide phase”). The sputtering target having such a structure is, for example, a so-called silicon-rich target having a composition in which the amount of silicon is larger than that of a stoichiometrically stable composition. Silicon is present as molybdenum silicide particles and silicon particles by containing more than the stoichiometrically stable composition of molybdenum and silicon (making it silicon-rich).

The molybdenum content and silicon content in the sputtering target of the present invention can be regarded as the mixing ratio (mol%) of molybdenum powder and silicon powder as raw materials. It can also be obtained by a method such as ICP analysis using an ICP (inductively coupled plasma emission spectroscopy) analyzer.

The sputtering target of the present invention is preferably composed of silicon alone and molybdenum silicide. However, as long as the advantageous effects of the present invention are not impaired, molybdenum alone, a solid solution of silicon and molybdenum, or a small amount of other metal elements. It is allowed to be included. The content of components other than silicon simple substance and molybdenum silicide is preferably 1.0% by mass or less with respect to the mass of the sputtering target.

The present invention is characterized in that the average particle size of the silicon particles of the sputtering target is controlled within a specific range, and the average particle size of the molybdenum silicide particles is controlled within a specific range. Specifically, the inventors have found that the generation of particles due to arcing during sputtering can be effectively suppressed by controlling the average particle size of silicon particles to preferably 2.0 μm or less. . From this viewpoint, the average particle size of the silicon particles is more preferably 1.9 μm or less, still more preferably 1.8 μm or less, and particularly preferably 1.7 μm or less. The average particle diameter of the silicon particles is not particularly limited, but is usually 0.1 μm or more.

On the other hand, the inventors have found that the generation of particles due to arcing during sputtering can be effectively suppressed by controlling the average particle diameter of molybdenum silicide particles to preferably 2.5 μm or less. From this viewpoint, the average particle diameter of the molybdenum silicide particles is more preferably 2.2 μm or less, further preferably 2.1 μm or less, and particularly preferably 2.0 μm or less. The average particle diameter of the molybdenum silicide particles is not particularly limited, but is usually 0.1 μm or more.

The average particle diameter of the silicon particles and the average particle diameter of the molybdenum silicide particles can be measured by the following method.
(Measuring method of average particle size)
First, the surface of the sputtering target material is polished and smoothed. About this smooth surface, an FE gun type scanning electron microscope (SUPRA55VP / Carl) equipped with an energy dispersive X-ray analysis (EDS) / electron beam backscatter diffraction analysis (EBSD) apparatus (Pegasus System / Ametech). EDS spectrum and EBSD pattern of silicon and molybdenum silicide are measured by Zeiss. The measurement conditions are an acceleration voltage of 20 kV, a magnification of 3000 times, an observation visual field of 10 μm × 20 μm, and a measurement interval of 0.02 μm. The crystal phases to be indexed are a silicon phase and a molybdenum silicide phase, which are distinguished from each other from the EDS spectrum. For the obtained data, select the analysis menu “Grain Size” of the EBSD analysis program (OIM Analysis / manufactured by TSL Solutions Co., Ltd.), and each area weighted average crystal grain size (μm) of silicon phase and molybdenum silicide phase Is calculated. At this time, when an orientation difference of 5 ° or more is detected, the grain boundary is identified as a general grain boundary, and a twin grain boundary having an orientation relationship of 70 ° rotation around the <001> axis is not regarded as a general grain boundary. Do. The measurement is performed randomly in 5 fields of view, and the average crystal grain size of the silicon phase and the molybdenum silicide phase in each field of view is calculated. A numerical value obtained by further averaging the average crystal grain sizes of the silicon phase and the molybdenum silicide phase obtained in each field of view is defined as the average crystal grain size of the silicon phase and the molybdenum silicide phase of the sputtering target.

In the sputtering target of the present invention, in addition to the average particle size of silicon particles in the silicon phase being equal to or less than the above value, the average number of pores having a major axis of 0.3 μm or more present in the silicon phase is 90 μm × 125 μm. One of the features is that the number is 10 or less in the rectangular range. The “vacancy” existing in the silicon phase can be rephrased as “void” or “defect”, and in short, is a space in which no substance exists in the silicon phase. If vacancies exist in the silicon phase, this is the starting point, and particles are likely to be generated due to arcing during sputtering. By reducing the size of the vacancies and reducing the number of particles, generation of particles As a result of the study by the present inventors, it has been found that the above can be effectively suppressed. The vacancies can be reduced by sufficiently growing the silicon particles in the silicon phase. However, if the average particle size of the silicon particles is excessively increased, as described above, it is caused by arcing during sputtering. Particle generation is likely to occur. Therefore, in the present invention, the generation of particles during sputtering is effectively suppressed by balancing the average particle diameter of the silicon particles in the silicon phase and the size of the pores.

From the viewpoint of making the above effect even more remarkable, the average number of vacancies having a major axis of 0.3 μm or more present in the silicon phase is 5 in a rectangular field of view of 90 μm × 125 μm in observation with a scanning electron microscope. The number is preferably not more than 3, and more preferably not more than 3.

The major axis of vacancies in the silicon phase and the average number of vacancies can be measured by the following method.
(Measuring method of the average number of holes having a major axis of 0.3 μm or more)
First, the surface of the sputtering target is polished and smoothed. This smooth surface is enlarged by a magnification of 1000 times using a scanning electron microscope (JXA-8800-R, manufactured by JEOL) to form a rectangular field of view of 90 μm × 125 μm. Further, it is magnified 5000 times and the number of holes having a major axis of 0.3 μm or more in the above-mentioned visual field is counted. The same measurement is performed randomly in 10 fields, and the average number of holes in each field is defined as the average number of holes having a major axis of 0.3 μm or more of the sputtering target. The major axis of the hole means the length of the appearing hole in the longest direction (see FIG. 1).

In order to control the average particle diameter of the silicon particles and the average particle diameter of the molybdenum silicide particles within the above-mentioned range and to control the long diameter of the vacancies in the silicon phase within the above-described range, for example, a discharge plasma sintering described later is performed. The target of the present invention is produced by combining a sintering method (hereinafter sometimes abbreviated as “SPS method”) and a hot isostatic pressing method (hereinafter also abbreviated as “HIP method”). It is advantageous.

The sputtering target of the present invention has a relative density of 99% or more, preferably 99.5% or more, more preferably 99.7% or more, and even more preferably 100% or more. More preferably, it is 100.5% or more. By increasing the relative density of the target, the pores (holes) of the target are reduced, so that the discharge is stabilized during sputtering and the generation of particles due to arcing can be prevented. The higher the relative density, the better. The upper limit is not particularly defined, but is usually 102%. The relative density is measured based on the Archimedes method. Specifically, the air mass of the sputtering target is divided by the volume (= the mass of the sputtering target in water / the specific gravity of the water at the measurement temperature), and the percentage value relative to the theoretical density ρ (g / cm ³ ) is the relative density (unit: %).

Since the sputtering target of the present invention is substantially composed of silicon and molybdenum silicide (MoSi ₂ ), the theoretical density ρ can be calculated from the following formula (1).

_{ρ = {(C 1/100} ) / ρ 1 + (C 2/100) / ρ 2} -1 ··· (1)

Silicon density: ρ ₁ = 2.33 g / cm ³
Mass% of silicon: C ₁
Density ρ _{2 of} molybdenum silicide (MoSi ₂ ): 6.24 g / cm ³
Mass% of molybdenum silicide (MoSi ₂ ): C ₂

The above C ₁ and C ₂ can be calculated from the analysis values obtained by analyzing the mass% of silicon and the mass% of molybdenum in the sputtering target of the present invention by ICP emission spectroscopy. In addition, since the relative density of the sputtering target of the present invention is a percentage value with respect to the theoretical density ρ (g / cm ³ ), it may exceed 100%. Since molybdenum alone, solid solution of silicon and molybdenum, and other elements are in small quantities, they can be ignored in calculating the theoretical density.

In the sputtering target of the present invention, it is preferable that aggregates having an equivalent circle diameter of 10 μm or more (hereinafter also referred to as “aggregates of molybdenum silicide particles”) due to aggregation of molybdenum silicide particles be 1 / mm ² or less. By controlling the agglomerates of molybdenum silicide particles to 1 piece / mm ² or less, it is possible to suppress the occurrence of arcing starting from the location of the agglomerates, and a sputtering target with less generation of particles due to arcing. Obtainable. In this respect, the aggregate of molybdenum silicide particles is more preferably 0.8 pieces / mm ² or less, further preferably 0.5 pieces / mm ² or less, and 0.2 pieces / mm ² or less. It is particularly preferred that The closer the number of aggregates of molybdenum silicide particles is to zero, the better.

The number of aggregates of molybdenum silicide particles can be measured as follows.
(Measuring method of aggregate)
First, the surface of the sputtering target is polished and smoothed. This smooth surface is magnified 200 times using a scanning electron microscope (JXA-8800-R, manufactured by JEOL), and 30 fields of a rectangular field of 0.5 mm × 0.65 mm are randomly photographed. Using the particle analysis software (particle analysis version 3.0, manufactured by Sumitomo Metal Technology Co., Ltd.), the number of aggregates having an equivalent circle diameter of 10 μm or more due to aggregation of molybdenum silicide particles is measured from the obtained image. The total number of the aggregates of the molybdenum silicide particles obtained and divided by 9.75 mm ² (0.5 mm × 0.65 mm × 30 fields) is defined as the number of molybdenum silicide particle aggregates per 1 mm ² .

Next, a preferred method for producing the sputtering target of the present invention will be described. The sputtering target of the present invention is preferably manufactured through a step of mixing molybdenum powder and silicon powder and subjecting the obtained mixed powder to a discharge plasma sintering method.

In order to obtain the target of the present invention, first, a powder of molybdenum alone and a powder of silicon simple substance are prepared, and both are mixed. As the molybdenum powder, it is preferable to use a powder having a specific surface area of 4.0 m ² / g or more as measured by the BET (Brunauer-Emmett-Teller) method from the viewpoint of obtaining a fine structure of the molybdenum silicide phase. From the viewpoint of making this advantage even more remarkable, the specific surface area of the molybdenum powder is preferably 5.0 m ² / g or more, and more preferably 6.0 m ² / g or more. The upper limit value of the specific surface area of the molybdenum powder is not particularly defined, but is preferably 8.0 m ² / g or less from the viewpoint of preventing aggregation of the molybdenum powder.

On the other hand, it is preferable to use a silicon powder having a specific surface area measured by the BET method of 4.0 m ² / g or more from the viewpoint of obtaining a microstructure of a silicon phase and a molybdenum silicide phase. From the viewpoint of making this advantage more remarkable, the specific surface area of the silicon powder is preferably 5.0 m ² / g or more, and more preferably 6.0 m ² / g or more. The upper limit value of the average particle diameter of the silicon powder is not particularly defined, but is preferably 8.0 m ² / g or less from the viewpoint of preventing aggregation of the silicon powder.

The specific surface area of the molybdenum powder and the silicon powder is, for example, a fully automatic specific surface area measuring device (Macsorb (registered trademark) HM －１ model-1210) manufactured by Mountec Co., Ltd., and a mixed gas (nitrogen 30 vol% + helium 70 vol%). ) And the BET single point method. As long as the specific surface area is within the above range, there is no particular limitation on the shape of the molybdenum powder and the silicon powder.

The mixing ratio of the molybdenum powder and the silicon powder is expressed in mol%, and the value of Mo / (Mo + Si) × 100 is preferably 3% or more and 25% or less, and is 3.3% or more and 24% or less. Is more preferably 3.5% or more and 23% or less. Further, the value of Si / (Mo + Si) × 100 is preferably 75% or more and 97% or less, more preferably 76% or more and 96.7% or less, and 77% or more and 96.5% or less. Is more preferable. By mixing molybdenum and silicon at this ratio, the target of interest can be successfully obtained.

Various mixing means can be used for mixing the molybdenum powder and the silicon powder. For example, a bead mill, a sand mill, an attritor (registered trademark), a medium stirring type mill such as a ball mill, a three-roll mill, or the like can be used. The diameter of the medium when using the medium stirring mill is preferably 5 mm or more and 20 mm or less. The material of the media is preferably zirconia or alumina, for example. Moreover, you may screen with respect to the obtained mixed powder using a sieve with an opening of 50 micrometers or less. The mixed powder that has been subjected to sieving may be calcined for the purpose of adjusting the specific surface area.

Next, the mixed powder is filled into a sintering die having a predetermined shape of the molding recess. As the sintering die, for example, a graphite die can be used, but it is not limited to this material. Once the sintered die is filled with the mixed powder, the mixed powder is subjected to the SPS method. The SPS method is one of solid compression sintering methods similar to a hot press sintering method (hereinafter abbreviated as “HP method”). In the SPS method, the mixed powder filled in the sintering die is heated while being pressurized. In the HP method, heating is performed while applying pressure, but the SPS method is different from the HP method in heating. In the HP method, the object to be sintered is heated from the outside for a long time using a heating element of a hot press apparatus, whereas in the SPS method, the on-off DC pulse voltage / current is conductive. Apply directly to the sintering die and the object to be sintered. The self-heating of the sintering die to which electric energy is directly input is used as a sintering driving force together with pressurization. In other words, in addition to the thermal and mechanical energy used for general sintering, electromagnetic energy by pulse energization, self-heating of the workpiece and discharge plasma energy generated between particles are combined and sintered. Driving power. According to the SPS method employing such a sintering method, a dense sintered body in which grain growth is suppressed can be produced. In short, it becomes possible to control the average particle diameter of the silicon particles and the average particle diameter of the molybdenum silicide particles within the above-described ranges.

From the viewpoint of successfully obtaining a target of interest, the rate of temperature increase when performing the SPS method is preferably 5 ° C./min or more and 20 ° C./min or less, preferably 10 ° C./min or more and 18 ° C./min or less. More preferably. Abnormal grain growth can be suppressed by setting the temperature rising rate to 5 ° C./min or more, and by suppressing the temperature increase to 20 ° C./min or less, temperature variation in the sintered body can be suppressed. it can. The sintering temperature is preferably 1100 ° C. or higher and 1200 ° C. or lower, more preferably 1120 ° C. or higher and 1200 ° C. or lower. By setting the firing temperature to 1100 ° C. or higher, it is possible to suppress the density of the sintered body from being lowered, and by setting it to 1200 ° C. or lower, generation of elution can be suppressed. The sintering temperature can be obtained by measuring the surface temperature of the sintering die using a radiation thermometer (manufactured by Chino, IR-AHS0). The pressure during sintering is preferably 25 MPa or more and 80 MPa or less, and more preferably 27 MPa or more and 50 MPa or less. The sintering holding time is preferably 20 minutes or more and 300 minutes or less, more preferably 30 minutes or more and 180 minutes or less, provided that the sintering temperature and pressure are in the above-mentioned ranges.

The sintering atmosphere can be a vacuum or an inert gas. When sintering is performed in a vacuum, it is preferable to employ conditions of 30 Pa or less, particularly 10 Pa or less in absolute pressure. When sintering is performed in an inert gas, argon or nitrogen can be used as the inert gas.

In this production method, it is advantageous to perform the HIP method following the SPS method. By producing a sputtering target by combining the SPS method and the HIP method, it is possible to effectively suppress the generation of vacancies in the silicon phase while suppressing the growth of silicon particles and molybdenum silicide particles.

From the viewpoint of successfully obtaining a target of interest, the rate of temperature rise when performing the HIP method is preferably 5 ° C./min or more and 20 ° C./min or less, preferably 10 ° C./min or more and 15 ° C./min or less. More preferably. Abnormal grain growth can be suppressed by setting the temperature rising rate to 5 ° C./min or more, and by suppressing the temperature increase to 20 ° C./min or less, temperature variation in the sintered body can be suppressed. it can. The temperature is preferably 1150 ° C. or higher and 1350 ° C. or lower, more preferably 1200 ° C. or higher and 1350 ° C. or lower. By setting the temperature to 1150 ° C. or higher, generation of vacancies in the silicon phase can be suppressed, and by setting the temperature to 1350 ° C. or lower, coarsening and melting of silicon particles can be suppressed. Moreover, generation | occurrence | production of a void | hole in a silicon phase can also be suppressed by making temperature into 1350 degrees C or less. The pressure is preferably 90 MPa or more, and more preferably 100 MPa or more. The upper limit of the pressure is not particularly defined, but is usually 200 MPa. The holding time is preferably not less than 30 minutes and not more than 240 minutes, more preferably not less than 60 minutes and not more than 180 minutes, provided that the temperature and pressure are in the above ranges.

When the sintering by the HIP method is completed, the heating is stopped and the cooling is performed. There is no restriction | limiting in particular in the system of cooling, It is easy to set it as natural cooling. By appropriately adjusting the above conditions, the target can be successfully obtained.

The sputtering target manufactured in this way is suitably used when forming a light semi-transmissive film (halftone phase shift film) of a mask blank which becomes an original plate when manufacturing a halftone phase shift mask, for example. As the substrate to be sputtered, for example, a translucent substrate such as transparent quartz glass is preferably used.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited to such embodiments.

[Example 1]
(1) Preparation of mixed powder for sintering Powder of silicon simple substance having specific surface area of 4.1 m ² / g by BET method and powder of molybdenum simple substance having specific surface area of 4.7 m ² / g by BET method Were weighed so that Mo: Si = 4: 96 (molar ratio). Both were mixed using Attritor (registered trademark) manufactured by Nippon Coke Co., Ltd. to obtain a mixed powder. The operating conditions of Attritor (registered trademark) were 24 hours at 280 rpm. A zirconia ball having a diameter of 10 mm was used as a medium. The mixed powder thus obtained was sieved with a sieve having an opening of 50 μm. The mixed powder thus sieved was calcined at 800 ° C. for 3 hours.

(2) Sintering by SPS Method The calcined mixed powder was filled in a sintering die made of graphite. The diameter of the sintering die was 230 mm. Subsequently, the mixed powder was sintered by the SPS method. The implementation conditions of the SPS method were as follows.
・ Sintering atmosphere: Vacuum (absolute pressure 10 Pa)
・ Raising rate: 10 ° C / min
・ Sintering temperature: 1175 ° C
・ Sintering holding time: 30 min
・ Pressure: 41 MPa
・ Cooling: Natural furnace cooling

(3) Sintering by HIP method, gas: argon, heating rate: 10 ° C / min
・ Sintering temperature: 1250 ° C
・ Sintering holding time: 120 min
・ Pressure: 145 MPa
・ Cooling: Natural furnace cooling

[Comparative Example 1]
In Example 1, the HIP method was not performed. Except for this, a sputtering target was obtained in the same manner as in Example 1.

[Example 2]
A sputtering target was obtained in the same manner as in Example 1 except that the conditions shown in Table 1 below were adopted.

[Comparative Example 2]
In Example 2, the HIP method was not performed. Except for this, a sputtering target was obtained in the same manner as in Example 1.

[Comparative Example 3]
This comparative example is an example in which the HIP method in Example 2 was performed under the conditions shown in Table 1 below. Other than that was carried out similarly to Example 2, and obtained the sputtering target.

Example 3
A sputtering target was obtained in the same manner as in Example 1 except that the conditions shown in Table 1 below were adopted.

[Comparative Example 4]
This comparative example is an example in which sintering was performed by the HP method under the conditions shown in Table 1 instead of the SPS method. Other than that was carried out similarly to Example 3, and obtained the sputtering target.

Example 4
A sputtering target was obtained in the same manner as in Example 1 except that the conditions shown in Table 1 below were adopted.

[Comparative Example 5]
In Example 4, the HIP method was not performed. Except for this, a sputtering target was obtained in the same manner as in Example 1.

[Evaluation]
About the target obtained by the Example and the comparative example, the average particle diameter of the silicon particle and the average particle diameter of molybdenum silicide particle | grains were measured with the above-mentioned method. Further, the number of vacancies having a major axis of 0.3 μm or more existing in the silicon phase (range of 90 μm × 125 μm) was measured. Further, the number of aggregates of molybdenum silicide particles was measured. Furthermore, the relative density of the target was measured. These results are shown in Table 1 below.

From the results shown in Table 1, all of the targets of Examples 1 to 4 have a silicon phase in which the average particle size of silicon particles is 2.0 μm or less and a molybdenum silicide phase in which the average particle size of molybdenum silicide particles is 2.5 μm or less. It can be seen that the average number of pores having a major axis of 0.3 μm or more existing in the silicon phase is 10 or less in the range of 90 μm × 125 μm.

Next, the following evaluation was performed on each sputtering target of Example 1 and Comparative Example 1 in order to verify the effect of particles generated when a thin film was formed by sputtering using these targets.

First, ten translucent substrates made of synthetic quartz glass having a main surface dimension of about 152 mm × about 152 mm and a thickness of about 6.25 mm were prepared. The translucent substrate has its end face and main surface polished to a predetermined surface roughness, and then subjected to a predetermined cleaning process and a drying process. Next, a defect inspection was performed with a defect inspection apparatus (M6640 manufactured by Lasertec Corporation) on the main surface on the thin film forming side of all of the prepared translucent substrates. In this defect inspection, defect data relating to the type of defect (convex defect, concave defect, etc.) present on the main surface on the thin film forming side of the inspected translucent substrate and the position (coordinate) of the defect is obtained. Obtained and recorded in association with the translucent substrate subjected to the defect inspection.

Next, the translucent substrate after the defect inspection was divided into two sets of one set. For each light-transmitting substrate in one set, a thin film was formed by a sputtering method using the sputtering target of Example 1, and a substrate with a thin film according to Example 1 was produced. Moreover, with respect to each of the translucent substrates in the other set, a thin film was formed by sputtering using the sputtering target of Comparative Example 1 to produce a substrate with a thin film according to Comparative Example 1.

Specifically, the following steps were performed. First, the sputtering target of Example 1 or Comparative Example 1 is attached to the cathode in the film forming chamber of the single-wafer DC sputtering apparatus, and the main surface on the side subjected to the defect inspection is the sputtering target on the substrate stage in the film forming chamber. A translucent substrate was installed so as to oppose. Subsequently, an atmosphere of a mixed gas of argon (Ar), nitrogen (N ₂ ), and helium (He) (gas flow rate Ar = 10.5 sccm, N ₂ = 48 sccm, He = 100 sccm, gas pressure = 0. 3 Pa), reactive sputtering was performed with a DC power supply of 3.0 kW, and a thin film made of molybdenum, silicon, and nitrogen was formed to a thickness of 67 nm on the main surface of the translucent substrate. A substrate with a thin film according to 1 or Comparative Example 1 was produced.

Next, the defect inspection was performed on the surface of each thin film of each thin film substrate according to Example 1 and each thin film substrate according to Comparative Example 1 with a defect inspection apparatus (M6640 manufactured by Lasertec Corporation). In this defect inspection, the defect-existing data relating to the type of defect (convex defect, concave defect, etc.) present on the surface of the inspected thin film and the position (coordinates) of the defect is obtained, and the substrate with the thin film subjected to the defect inspection Recording was performed in association with (translucent substrate).

Finally, for each thin film-attached substrate of Example 1 and Comparative Example 1, an operation for extracting only defects that occurred when the thin film was formed by the sputtering method was performed. Specifically, the defect data on the main surface of the translucent substrate associated with the same translucent substrate are compared with the defect data on the surface of the thin film, and exist at a position (coordinates) common to the two defect data. The defect to be removed was excluded from the defect data on the surface of the thin film, and this was recorded as the defect data of the defect (film defect) generated during the formation of the thin film in association with the substrate with the thin film (translucent substrate).

As a result of the above verification, the average number of film defects of the five thin film-attached substrates according to Example 1 was reduced to 1/25 of the average number of film defects of the five thin film-attached substrates according to Comparative Example 1. It was confirmed that From these results, it can be said that by forming a thin film by the sputtering method using the sputtering target of Example 1, generation of particles due to arcing from the sputtering target during sputtering can be sufficiently suppressed.

According to the present invention, there are provided a Mo—Si based sputtering target in which generation of particles is suppressed as compared with the conventional method and a method for manufacturing the same.

Claims

A sputtering target having a molybdenum content of 3 mol% to 25 mol% and a silicon content of 75 mol% to 97 mol%,
A silicon phase having an average particle diameter of 2.0 μm or less and a molybdenum silicide phase having an average particle diameter of molybdenum silicide particles of 2.5 μm or less;
A sputtering target in which the average number of pores having a major axis of 0.3 μm or more present in the silicon phase is 10 or less in the range of 90 μm × 125 μm.
2. The sputtering target according to claim 1, wherein the number of aggregates having an equivalent circle diameter of 10 μm or more due to aggregation of molybdenum silicide particles is 1 or less per 1 mm 2 .
The sputtering target according to claim 1 or 2, wherein the relative density is 99% or more.
It is a manufacturing method of the sputtering target as described in any one of Claim 1 thru | or 3, Comprising:
Mixing molybdenum powder and silicon powder,
The obtained mixed powder is subjected to a discharge plasma sintering method, and then subjected to a hot isostatic pressing method,
The manufacturing method of the sputtering target whose sintering temperature in the process attached | subjected to the said hot isostatic pressing method is 1150 degreeC or more and 1350 degrees C or less.
The manufacturing method according to claim 4, wherein a sintering temperature in the step of subjecting to the discharge plasma sintering method is 1100 ° C. or more and 1200 ° C. or less.