JP4880809B2 - Sputtering target manufacturing method, sputtering target, metal silicide film, wiring, electrode, and electronic component using the same - Google Patents

Description

表１から明らかなように、遊離Ｓｉ相の残留応力を750MPa以下とすると共に、ラマンスペクトルの遊離Ｓｉピークの半値幅を10cm-1以下とした、実施例１〜６による金属シリサイドターゲットによれば、比較例１〜３および比較例５〜６に比べてパーティクルの発生数が大幅に低減していることが分かる。
【００９７】
さらに、上記した各実施例によるシリサイドターゲットを用いて、半導体デバイスおよびＬＣＤ素子の電極および配線を形成したところ、これら半導体デバイスやＬＣＤ素子の歩留りおよび品質が向上することが確認された。すなわち、高品質の電子部品を高歩留りで得ることができる。
【００９８】
【発明の効果】
以上説明したように、本発明のスパッタリングターゲットによれば、遊離Ｓｉ相の残留応力などに起因するパーティクルの発生を大幅に抑制することができる。従って、半導体素子や液晶表示素子などに代表される電子部品の配線、電極、素子構成膜などとして使用される金属シリサイド薄膜の品質を大幅に向上させることが可能となる。
【図面の簡単な説明】
【図１】 本発明のスパッタリングターゲットにおける遊離Ｓｉ相の残留応力を求めるためのラマンスペクトルのＳｉピークのシフト状態を示す図である。
【図２】 本発明のスパッタリングターゲットにおける遊離Ｓｉ相の残留応力の測定方法を説明するための図である。[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a sputtering target made of metal silicide.ToManufacturing methodAnd sputtering targets andThe present invention relates to a metal silicide film, wiring, electrode, and electronic component using the same.
[0002]
[Prior art]
In an electronic component typified by a semiconductor element or a liquid crystal display element, a silicide compound of a refractory metal such as W, Mo, Ta, Ti, Zr, or Co is used as a wiring or electrode forming material or an element constituent film. in use. In particular, the delay of electrical signals has become a problem due to the thinning of electrodes and wiring due to high integration and high density of semiconductor elements, but metal silicide thin films such as W and Mo having low resistance values have low resistance. It is useful as a material for forming a simple electrode or wiring. The metal silicide thin film is also effective for suppressing electromigration.
[0003]
As a method for forming a thin film made of a refractory metal silicide compound such as W or Mo (WSi 2 or MoSi 2), a sputtering method and a CVD method can be cited as typical film forming methods. In particular, sputtering is generally used from the viewpoints of stability and manufacturing cost.
[0004]
When the metal silicide thin film as described above is formed by sputtering, it is necessary to produce a sputtering target with metal silicide. Here, as a general sputtering target manufacturing method, a melting method applying electron beam (EB) melting or the like, or a powder sintering method applying hot press (HP), hot isostatic pressing (HIP), or the like. It has been known.
[0005]
In the case of producing a metal silicide target, a powder sintering method is generally used because the composition control of the metal silicide film to be formed is easy (see, for example, Japanese Patent Laid-Open No. 5-145523). . Specifically, refractory metal (M) powder such as W or Mo and silicon (Si) powder are first mixed so that the atomic ratio of Si is about 2 to 4, and the mixed powder is subjected to heat treatment. After synthesizing the metal silicide, the metal silicide target is manufactured by applying HP, HIP, or the like and performing pressure sintering in a high vacuum under a high pressure.
[0006]
[Problems to be solved by the invention]
By the way, in the sputter film formation using the metal silicide target as described above, particles resulting from the target and the apparatus are recognized as a serious problem as the semiconductor elements and the like are highly integrated and highly functional. . This particle is, for example, a fine particle having a diameter of about 0.2 to 10 μm, and if such a fine particle is mixed in a thin film formed, it causes a short circuit between wirings or a wiring open defect. The manufacturing yield of electronic parts such as semiconductor elements and liquid crystal display elements is reduced.
[0007]
A conventional metal silicide target by a powder sintering method has a fine structure in which a fine Si phase is arranged in a gap between MSi2 phases, and a density of, for example, 99% or more is obtained. When such a conventional metal silicide target is used and a metal silicide film is formed by sputtering, the generation level of particles is about 30 to 60 particles / wafer on average.
[0008]
However, with the recent high integration and high density of semiconductor elements, the required particle level is becoming stricter year by year, and the conventional generation level of particles as described above cannot sufficiently cope with it. . For this reason, in order to improve the manufacturing yield of semiconductor elements and other devices that are being highly integrated and increased in density, the amount of particles generated due to the metal silicide target by the powder sintering method is greatly reduced. It is strongly desired to do so.
[0009]
  The present invention has been made to cope with such a problem, and it is possible to greatly suppress the generation of particles due to the internal structure and internal state of a metal silicide target.ToProduction methodAnd sputtering target obtained therebyThe purpose is to provide.
[0010]
[Means for Solving the Problems]
As a result of various investigations to suppress the generation of particles that are considered to be caused by the internal structure and internal state of the metal silicide target by the powder sintering method, the present inventors have released the internal residual stress of the target during sputtering. It was found that this is one of the generation factors of particles. When the metal silicide target has a microstructure in which a free Si phase is present in the gap between the metal silicide phases (MSi2 phase), the release of internal stress in the free Si phase has a strong influence on the generation of such particles. I found out. Furthermore, the internal defect of the free Si phase and the like are the cause of particle generation.
[0011]
Particles based on the release of the residual stress of the free Si phase as described above can be greatly suppressed by releasing the residual stress of the target in advance. The present invention has been made on the basis of such knowledge, and by allowing the residual stress of the free Si phase to be released to a certain value or less, the generation of particles can be greatly suppressed. It is. Furthermore, it is possible to further suppress the generation of particles by reducing the internal defects of the free Si phase.
[0012]
  The sputtering target as described above is a sputtering target obtained by applying the production method of the present invention.That is, the sputtering target of the present inventionManufacturing methodAs described in claim 1,
General formula: MSi _x
(Wherein M represents at least one element selected from W, Mo, Ta, Ti, Zr, Hf, Ni and Co, and x represents a number satisfying 2 ≦ x ≦ 4)
The metal silicide powder represented by is sintered under pressure to produce a densified metal silicide sintered body, and the pressure applied to the metal silicide sintered body is released following the sintering process. In this state, the heat treatment is performed at a temperature of 1000 to 1380 ° C. and then cooled to room temperature, and the metal silicide sintered body that has undergone the heat treatment step is processed into a desired target shape.
[0013]
  The sputtering target of the present invention is a sputtering target manufactured by the above-described manufacturing method of the present invention, and is a free Si that is discontinuously present in the gap between the metal silicide phase formed in a chain and the metal silicide phase. A sputtering target having a microstructure including a phase.
  further,In the sputtering target of the present inventionIsResidual stress of free Si phaseBut laShift amount of free Si peak in Raman spectrum of Mann spectroscopy (Δν (unit: cm^-1)) From the formula: (2.5 × 109 × △ ν) × 10^-1Value calculated based on the stress conversion formula expressed in [Pa]It is characterized by being 750 MPa or less.
[0014]
  As described above, by setting the residual stress based on Raman spectroscopy of the free Si phase among the constituent phases of the metal silicide target to 750 MPa or less, the generation of particles due to the above-described release of stress in the free Si phase is greatly reduced. It becomes possible to do. Furthermore, in the sputtering target of the present invention,, TaThe variation of the residual stress of the free Si phase as a whole of the target is preferably within 20%.
[0015]
  The sputtering target of the present invention further comprisesAnd laThe half-width of the free Si peak in the Raman spectrum of Mann spectroscopy is 10 cm.^-1It is characterized by the following. The full width at half maximum of the free Si peak in the Raman spectrum tends to increase when there are many free Si phase internal defects. That is, the half width of the free Si peak is 10 cm.^-1According to the metal silicide target described below, generation of particles due to internal defects in the free Si phase can be suppressed.
[0016]
  MaIn addition, the metal silicide film of the present invention is formed using the sputtering target of the present invention. The wiring of the present invention is characterized by comprising a metal silicide film formed using the sputtering target of the present invention. The electrode of the present invention is characterized by comprising a metal silicide film formed using the sputtering target of the present invention. The electronic component of the present invention is characterized by including a metal silicide film formed using the sputtering target of the present invention. Examples of the electronic component of the present invention include a semiconductor element and a liquid crystal display element.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, modes for carrying out the present invention will be described.
[0018]
The sputtering target of the present invention is
General formula: MSix (1)
(Wherein M represents at least one element selected from W, Mo, Ta, Ti, Zr, Hf, Ni and Co, and x represents a number satisfying 2 ≦ x ≦ 4)
It consists of the metal silicide represented by these.
[0019]
Here, the value of x is basically set from the Si amount constituting MSi2 and the excessive Si amount (Si constituting the free Si phase). If the value of x is less than 2, the target metal silicide (MSi2) thin film cannot be obtained with good reproducibility. On the other hand, if the value of x exceeds 4, the amount of excessive Si is too large, resulting in an increase in resistance value, which may adversely affect various elements. More preferably, the value of x is in the range of 2.5 to 3.2.
[0020]
The metal silicide target according to the present invention has a microstructure in which the free Si phase formed by combining the excessive Si particles described above is discontinuously present in the gaps between the MSi2 phases (metal silicide phases) formed in a chain. It is what has. In this way, by making the Si phase discontinuously exist in the gap between the MSi2 phases, the bonding state between the MSi2 phases can be enhanced.
[0021]
In the sputtering target (metal silicide target) of the present invention, the residual stress of the free Si phase based on the excessive Si described above is obtained as a value obtained from the shift amount (Δν) of the free Si peak due to the Raman spectrum of Raman spectroscopic analysis. 750MPa or less. Thus, by reducing the residual stress of the free Si phase, it is possible to greatly reduce the amount of particles generated due to the release of the stress of the free Si phase during sputtering.
[0022]
That is, one of the causes of generation of particles in the metal silicide target is that the internal residual stress of the target is released during sputtering. For example, the residual stress generated mainly in the process of producing the target material is released by irradiation energy such as Ar during sputtering, and along with the release of the stress, the sputter surface is broken or missing, and further abnormal discharge occurs. Foreign matter generated due to destruction or missing on the sputtered surface or abnormal discharge is mixed in the formed metal silicide film as particles, causing a problem.
[0023]
In particular, the release of the internal stress of the free Si phase has a strong influence on the particles based on the stress release described above. That is, when a metal silicide target is produced by pressure sintering, tensile or compressive stress is easily applied to the free Si phase as the metal silicide phase grows. Such internal stress of the free Si phase is released by the impact during sputtering, and particles are generated.
[0024]
Particles resulting from the release of stress in the free Si phase are greatly reduced by previously releasing the residual stress of the metal silicide target, particularly the residual stress of the free Si phase, and suppressing the release of stress due to sputtering energy. It becomes possible. The residual stress of the metal silicide target is, for example, a pressure sintering process for a metal silicide sintered body produced by pressure sintering by hot pressing (HP) or hot isostatic pressing (HIP), that is, a target material. Subsequent to the (high temperature holding process under pressure), heat treatment is performed at a temperature of 1000 to 1380 ° C with the applied pressure released (no pressure applied), and then cooled to room temperature, greatly reducing stress (relieving stress) )can do.
[0025]
By passing through the heat treatment process as described above, a metal silicide sintered body having a free Si phase residual stress of 750 MPa or less is obtained. And according to the metal silicide target obtained by processing such a metal silicide sintered body into a desired target shape, the value obtained from the shift amount (Δν) of the free Si peak due to the Raman spectrum of Raman spectroscopy analysis The residual stress of the free Si phase can be made 750 MPa or less. As described above, by setting the residual stress of the free Si phase existing in the target structure to 750 MPa or less, the generation of particles based on the release of the stress of the free Si phase during sputtering can be significantly suppressed.
[0026]
Here, Raman spectroscopy is widely used for composition and structure analysis in various fields such as chemistry, physics, medicine, and pharmacy. Specifically, the sample surface is irradiated by utilizing the fact that the spectrum of the Raman scattered light generated from the part irradiated with the light beam from the laser light source varies depending on the chemical species and molecules present in the part. This is a method for performing a two-dimensional distribution analysis, and information on chemical bonds and crystal structures can also be obtained directly. By using visible light having a short wavelength, analysis can be performed down to the submicron order.
[0027]
In the Raman spectroscopic analysis described above, the Si peak of the Raman spectrum is shifted by internal stress. The stress dependence of the Raman spectrum peak of Si is described in, for example, Jpn. J. Appl. Phys., 33 (1994) 4491 (H. Watanabe). According to this, poly-Si gives a sharp Raman scattering peak in the vicinity of a wavelength of 520 cm-1, and this peak shifts due to the internal stress of poly-Si as shown in FIG. Between the shift amount Δν [cm-1] from this wave number and the internal stress σ [Pa],
σ = (2.5 × 109 × △ ν) × 10-1 [Pa]… (2)
The relationship exists. When the shift direction of the Si peak is higher than the reference peak, it indicates a compressive stress, and when it is lower, it indicates a tensile stress. Note that the absolute value of the shift amount of the Si peak is substituted for Δν in the above equation (2).
[0028]
Therefore, the residual stress can be measured and evaluated from the shift amount Δν of the Si peak of the Raman spectrum by performing the Raman spectroscopic analysis of the free Si phase using the laser beam with a reduced beam size. The present invention is characterized in that the residual stress of the free Si phase of the metal silicide target is set to 750 MPa or less as a value measured by this Raman spectroscopic analysis. The residual stress of the free Si phase is more preferably 650 MPa or less, and further preferably 550 MPa or less.
[0029]
The residual stress of the free Si phase existing in the target structure is more preferably within 20% of the variation of the target as a whole. Thus, by reducing the average residual stress of the free Si phase of the entire metal silicide target, it is possible to suppress variations in the amount of particles generated by each part in the target. That is, the generation amount of particles can be suppressed as a whole metal silicide target, and a higher quality metal silicide thin film can be obtained. The variation in the residual stress of the free Si phase as a whole target is more preferably within 10%.
[0030]
Furthermore, the shape of the Si peak of the Raman spectrum by Raman spectroscopic analysis indicates the state of poly-Si internal defects. That is, the full width at half maximum of the Si peak is increased according to the degree of internal defects present in poly-Si (free Si phase). For this reason, the half width of the free Si peak in the Raman spectrum of the Raman spectroscopic analysis is preferably 10 cm -1 or less.
[0031]
That is, the fact that the half width of the Si peak is 10 cm-1 or less means that there are few internal defects in the free Si phase. Therefore, according to such a metal silicide target, generation of particles due to internal defects in the free Si phase can be suppressed, and the amount of particles generated during the formation of the metal silicide film can be further reduced. It becomes. More preferably, the full width at half maximum of the free Si peak in the Raman spectrum of the Raman spectroscopic analysis is 5 cm -1 or less.
[0032]
Here, the residual stress of the free Si phase in the target structure defined in the present invention (residual stress by Raman spectroscopic analysis) and the half width of the free Si peak (half width of the Si peak in the Raman spectrum) are as follows. The determined value shall be indicated.
[0033]
That is, as shown in FIG. 2, for example, the center part (position 1) of the disk-shaped target, and the positions near the outer periphery (positions 2 to 9) on four straight lines that pass through the center part and equally divide the circumference, Samples with a length of 10 mm and a width of 10 mm were sampled from the half distance positions (positions 10 to 17), and Raman spectroscopic analysis was performed on these 17 test pieces. The shift amount Δν and the half width are measured. The Raman spectroscopic analysis is performed focusing on the free Si phase. The residual stress of the free Si phase is determined from the obtained Si peak shift amount Δν based on the aforementioned equation (2). And the value which averaged each of these values is made into the residual stress of a free Si phase, and the half value width of Si peak, respectively.
[0034]
In addition, the variation of the residual stress of the free Si phase as a whole of the target is first determined from the Si peak shift amount Δν obtained from the 17 test pieces described above based on the above-described equation (2), respectively. Ask. And the value calculated | required based on the formula of {(maximum value-minimum value) / (maximum value + minimum value)} * 100 from the maximum value and minimum value of the obtained residual stress (sigma) shall be shown.
[0035]
The sputtering target (metal silicide target) of the present invention can be manufactured, for example, as follows.
[0036]
That is, first, the M element powder and the Si powder as raw materials are mixed so as to have a desired composition ratio. The particle size (maximum particle size) of these raw material powders is preferably 10 μm or less in order to obtain a good mixed state. Such a mixed powder is heat-treated at a temperature corresponding to the M element used to synthesize a metal silicide (MSix = MSi2 + Six-2).
[0037]
Next, the metal silicide calcined body is pulverized to form a metal silicide powder. The obtained metal silicide powder is filled into a molding die made of graphite, for example, and pressure-sintered by hot pressing (HP) to produce a densified metal silicide sintered body. Note that the HIP process may be applied to the pressure sintering of the metal silicide powder. When applying a hot press to a pressure sintering process, it is preferable to sinter at the temperature of 1200-1380 degreeC, applying the pressure of 24.5-34.3 MPa in a vacuum atmosphere. The sintering time is preferably 3 to 6 hours.
[0038]
After pressure sintering by hot pressing, etc., it is usually cooled to room temperature by cooling the atmospheric fan, etc., but in the present invention, following the pressure sintering process (high temperature holding process under pressure), the applied pressure In the open state, heat treatment is performed at a temperature of 1000 to 1380 ° C., and then cooled to room temperature. This heat treatment is preferably performed in a vacuum of 7 × 10 −2 Pa or less. In this way, by performing heat treatment on the metal silicide sintered body without pressure after performing pressure sintering, the residual stress of the free Si phase in the metal silicide target is greatly reduced (stress release). be able to.
[0039]
Furthermore, since the heat treatment described above also plays a role of matching the arrangement of crystal lattices, it effectively acts to remove internal defects in the free Si phase. That is, by subjecting the metal silicide sintered body to the heat treatment as described above after pressure sintering, the full width at half maximum of the free Si peak in the Raman spectrum can be reduced to 10 cm −1 or less with good reproducibility.
[0040]
The above-described heat treatment for releasing stress and removing internal defects is performed at a temperature in the range of 1000 to 1380 ° C. When the heat treatment temperature is less than 1000 ° C., the residual stress of the free Si phase cannot be sufficiently released, and internal defects are not sufficiently removed. On the other hand, when the heat treatment temperature exceeds 1380 ° C., the temperature becomes just below the melting point of Si, the free Si phase becomes unstable, and it becomes difficult to control the composition and maintain the target structure. The heat treatment temperature is more preferably in the range of 1000 to 1200 ° C. The heat treatment time is preferably in the range of 2 to 10 hours.
[0041]
Thereafter, the metal silicide sintered body (target material) heat-treated under the above conditions is machined to obtain a desired target shape. At this time, it is preferable to apply lapping, polishing, CMP, or the like to the surface processing (finishing) of the sputter surface. That is, the magnitude of the residual stress on the target surface varies depending on the surface processing method, and residual stress is likely to occur in the conventional surface grinding method. On the other hand, the target surface can be smoothed by machining the target material to the desired dimensions and then finishing the surface by lapping, polishing, CMP, etc., and the target surface (especially the sputter surface) Residual stress can be reduced.
[0042]
And the sputtering target of this invention is obtained by joining the target material machined and surface-finished to the desired shape with the backing plate which consists of Al, Cu, etc. as needed.
[0043]
The sputtering target of the present invention is used for forming, for example, electrodes and wiring films of various electronic devices. In particular, it is suitably used when forming a gate electrode of a semiconductor device. Since the metal silicide film formed using the sputtering target of the present invention has a small amount of mixed particles, it greatly contributes to the improvement of the manufacturing yield of semiconductor devices that are being highly integrated and densified. In addition, the metal silicide film formed by the sputtering target of the present invention is not limited to a semiconductor device, and can be applied to various electronic components such as a SAW device, TPH, and LCD device.
[0044]
【Example】
Next, specific examples of the present invention will be described.
[0045]
Example 1
First, a high-purity W powder with a maximum particle size of about 10 μm and a Si powder with a maximum particle size of 30 μm or less were blended so that the atomic ratio (x) of Si / W was 2.8. It mixed for 48 hours with the substituted ball mill. This mixed powder was subjected to a heat treatment for the silicidation under conditions of 1200 ° C. × 1 h, and the obtained calcined body was pulverized to obtain a W silicide powder.
[0046]
After filling the above-mentioned W silicide powder into a molding die made of graphite, it is set in a hot press machine, and first, while applying a pressure of 34.3 MPa in a vacuum of 5 × 10 −4 Pa or less, 1350 ° C. × 5 h Densification and sintering were performed under the following conditions. Subsequent to the pressure heating process for densification sintering, the applied pressure is removed while maintaining the above-described vacuum atmosphere, and the W silicide sintered body is subjected to 1200 ° C. × 5 h under this non-pressurized state. Heat treatment was applied. Thereafter, the atmosphere was cooled to room temperature.
[0047]
The W silicide sintered body that had been subjected to the pressureless heat treatment was machined to a desired target size, and the sputtered surface was finished by polishing. The surface roughness of the sputtered surface after finishing was 0.04 μm in Ra. In this way, two W silicide targets (diameter 127 mm × thickness 6 mm) were produced.
[0048]
Of the two W silicide targets obtained in this way, for one target, specimens were taken from each part shown in FIG. 2, and each surface was mirror-polished with diamond paste, and each was subjected to the following conditions. The Raman spectrum of the free Si phase was measured. Raman spectroscopic analysis is a device: a Raman spectroscope manufactured by Renishaw, irradiation light: Ar + ion laser (λ = 514.5 nm, output = 15 mW), beam size: diameter of about 1 μm, peak wave number: approximated by Lorentz curve, It carried out on condition of this. The Si (111) wafer was used as a Si peak reference sample, and each value was measured with the resulting Raman peak as zero stress.
[0049]
The Si peak shift amount Δν was measured from the obtained Raman spectra, and the residual stress of the free Si phase was calculated from the shift amount Δν based on the above-described equation (2). The average value of these residual stress values was determined as the residual stress σ of the free Si phase of the W silicide target according to Example 1. Moreover, the variation in the residual stress of the free Si phase was determined according to the method described above. Further, the half width of the Si peak was measured from the obtained Raman spectrum, and the average value of these values was obtained as the half width of the free Si peak.
[0050]
As a result, in the W silicide target of Example 1, the average value of the shift amount Δν of the free Si peak is 1.41 cm −1, and the average value of the residual stress σ obtained from each shift amount Δν is 352 MPa. The average half-width of the Si peak was 4.30 cm-1.
[0051]
Next, the other W silicide target was bonded to a Cu backing plate, and then set in a sputtering apparatus (ULVAC SH-550). Using such a sputtering apparatus, a W silicide film having a thickness of 200 nm was formed on a 5-inch Si wafer. The sputtering conditions were Ar pressure = 0.27 Pa, Ar flow rate = 80 sccm, and Power = 0.5 kW. Sputter deposition was performed sequentially on 24 Si wafers, and the number of particles of 0.2 μm or more present in the W silicide film on each Si wafer was examined, and the average value was obtained. As a result, the number of particles of 0.2 μm or more was 3 / sheet.
[0052]
Example 2
For the W silicide sintered body that has been subjected to densification and sintering under the same conditions as in Example 1, the pressure is removed while maintaining the vacuum atmosphere following the pressurizing and heating step, and 1000 W under this non-pressurized state. Heat treatment was performed under the condition of ℃ × 3h. Thereafter, the atmosphere was cooled to room temperature.
[0053]
The W silicide sintered body that has undergone the above-described pressureless heat treatment was machined to a desired target dimension, and the sputtered surface was further finished by CMP. The surface roughness of the sputtered surface after finishing was 0.03 μm in Ra. In this way, two W silicide targets (diameter 127 mm × thickness 6 mm) were produced.
[0054]
One of the two W silicide targets thus obtained was subjected to Raman spectroscopic analysis, and the Raman spectrum was measured in the same manner as in Example 1. As a result, in the W silicide target of Example 2, the average value of the shift amount Δν of the free Si peak is 2.35 cm −1, and the average value of the residual stress σ obtained from each shift amount Δν is 587 MPa. The average half-width of the Si peak was 6.23 cm-1.
[0055]
Next, after bonding the other W silicide target to a Cu backing plate, it was set in a sputtering apparatus (SH-550 manufactured by ULVAC), and a W silicide film was formed in the same manner as in Example 1. As a result, the number (average value) of particles of 0.2 μm or more present in the W silicide film was 14 / sheet.
[0056]
Example 3
For the W silicide sintered body that has been subjected to densification and sintering under the same conditions as in Example 1, the applied pressure was removed while maintaining the vacuum atmosphere following the pressurizing and heating step. Heat treatment was performed under the condition of ℃ × 5h. Thereafter, the atmosphere was cooled to room temperature.
[0057]
The W silicide sintered body that has undergone the above-described pressureless heat treatment was machined to a desired target size, and the sputtered surface was further polished by polishing. The surface roughness of the sputtered surface after finishing was Ra, 0.05 μm. In this way, two W silicide targets (diameter 127 mm × thickness 6 mm) were produced.
[0058]
One of the two W silicide targets thus obtained was subjected to Raman spectroscopic analysis, and the Raman spectrum was measured in the same manner as in Example 1. As a result, in the W silicide target of Example 3, the average value of the shift amount Δν of the free Si peak was 1.84 cm −1, and the average value of the residual stress σ obtained from each shift amount Δν was 459 MPa. The average half-width of the Si peak was 4.24 cm-1.
[0059]
Next, after bonding the other W silicide target to a Cu backing plate, it was set in a sputtering apparatus (SH-550 manufactured by ULVAC), and a W silicide film was formed in the same manner as in Example 1. As a result, the number (average value) of 0.2 μm or more particles present in the W silicide film was 9 / sheet.
[0060]
Example 4
For the W silicide sintered body that has been subjected to densification and sintering under the same conditions as in Example 1, the applied pressure was removed while maintaining the vacuum atmosphere following the pressurization and heating step. Heat treatment was performed under the condition of ℃ × 4h. Thereafter, the atmosphere was cooled to room temperature.
[0061]
The W silicide sintered body that has undergone the above-described pressureless heat treatment was machined to a desired target size, and the sputtered surface was further polished by polishing. The surface roughness of the sputtered surface after finishing was Ra, 0.05 μm. In this way, two W silicide targets (diameter 127 mm × thickness 6 mm) were produced.
[0062]
One of the two W silicide targets thus obtained was subjected to Raman spectroscopic analysis, and the Raman spectrum was measured in the same manner as in Example 1. As a result, in the W silicide target of Example 4, the average value of the shift amount Δν of the free Si peak is 2.08 cm −1, and the average value of the residual stress σ obtained from each shift amount Δν is 519 MPa. The average half-width of the Si peak was 4.90 cm-1.
[0063]
Next, after bonding the other W silicide target to a Cu backing plate, it was set in a sputtering apparatus (SH-550 manufactured by ULVAC), and a W silicide film was formed in the same manner as in Example 1. As a result, the number (average value) of 0.2 μm or more particles present in the W silicide film was 10 / sheet.
[0064]
Example 5
First, a high-purity Mo powder having a maximum particle size of about 10 μm and a Si powder having a maximum particle size of 30 μm or less were blended so that the atomic ratio (x) of Si / Mo was 2.2. It mixed for 24 hours by the substituted ball mill. This mixed powder was subjected to a heat treatment for the silicidation under conditions of 1200 ° C. × 1 h, and the obtained calcined body was pulverized to obtain a Mo silicide powder.
[0065]
After filling the above-mentioned Mo silicide powder into a molding die made of graphite, set it in a hot press device, and first apply a pressure of 34.3 MPa in a vacuum of 5 × 10 −4 Pa or less, 1350 ° C. × 4 h Densification and sintering were performed under the following conditions. Subsequent to the pressure heating process for densification sintering, the applied pressure is removed while maintaining the above-described vacuum atmosphere, and the Mo silicide sintered body is subjected to 1200 ° C. × 5 h under this non-pressurized state. Heat treatment was applied. Thereafter, the atmosphere was cooled to room temperature.
[0066]
The Mo silicide sintered body subjected to the pressureless heat treatment was machined to a desired target size, and the sputtered surface was further finished by polishing. The surface roughness of the sputtered surface after finishing was 0.08 μm in Ra. In this way, two Mo silicide targets (diameter 127 mm × thickness 6 mm) were produced.
[0067]
One of the two Mo silicide targets thus obtained was subjected to Raman spectroscopic analysis, and the Raman spectrum was measured in the same manner as in Example 1. As a result, in the Mo silicide target of Example 5, the average value of the shift amount Δν of the free Si peak is 1.53 cm −1, and the average value of the residual stress σ obtained from each shift amount Δν is 382 MPa. The average half-width of the Si peak was 4.51 cm-1.
[0068]
Next, the other Mo silicide target was bonded to a Cu backing plate, and then set in a sputtering apparatus (ULVAC SH-550). Using such a sputtering apparatus, a Mo silicide film having a thickness of 200 nm was formed on a 5-inch Si wafer. The sputtering conditions were Ar pressure = 0.27 Pa, Ar flow rate = 80 sccm, and Power = 0.5 kW. Sputter deposition was performed sequentially on 24 Si wafers, and the number of particles of 0.2 μm or more present in the Mo silicide film on each Si wafer was examined, and the average value was obtained. As a result, the number of particles of 0.2 μm or more was 10 / sheet.
[0069]
Example 6
First, a high-purity Ta powder having a maximum particle size of about 10 μm and a Si powder having a maximum particle size of 30 μm or less are blended so that the atomic ratio (x) of Si / Ta is 2.7, and this is mixed with high-purity Ar gas. It mixed for 24 hours by the substituted ball mill. The mixed powder was heat-treated for a silicidation reaction at 1200 ° C. × 1 h, and the obtained calcined body was pulverized to obtain a Ta silicide powder.
[0070]
After filling the above-mentioned Ta silicide powder into a graphite mold, set it in a hot press machine, and first apply a pressure of 34.3 MPa in a vacuum of 5 × 10 −4 Pa or less, 1380 ° C. × 4 h Densification and sintering were performed under the following conditions. Subsequent to the pressure heating process for densification sintering, the applied pressure is removed while maintaining the above-described vacuum atmosphere, and the Ta silicide sintered body is subjected to 1300 ° C. × 4 h under the non-pressurized state. Heat treatment was applied. Thereafter, the atmosphere was cooled to room temperature.
[0071]
The Ta silicide sintered body subjected to the pressureless heat treatment was machined to a desired target dimension, and the sputtered surface was finished by CMP. The surface roughness of the sputtered surface after finishing was 0.08 μm in Ra. In this way, two Ta silicide targets (diameter 127 mm × thickness 6 mm) were produced.
[0072]
One of the two Ta silicide targets thus obtained was subjected to Raman spectroscopic analysis, and the Raman spectrum was measured in the same manner as in Example 1. As a result, in the Ta silicide target of Example 6, the average value of the shift amount Δν of the free Si peak is 2.71 cm −1, and the average value of the residual stress σ obtained from each shift amount Δν is 677 MPa. The average half-width of the Si peak was 7.28 cm-1.
[0073]
Next, the other Ta silicide target was bonded to a Cu backing plate, and then set in a sputtering apparatus (ULVAC SH-550). Using such a sputtering apparatus, a Ta silicide film having a thickness of 200 nm was formed on a 5-inch Si wafer. The sputtering conditions were Ar pressure = 0.27 Pa, Ar flow rate = 80 sccm, and Power = 0.5 kW. Sputter deposition was performed sequentially on 24 Si wafers, and the number of particles of 0.2 μm or more present in the Ta silicide film on each Si wafer was examined, and the average value was obtained. As a result, the number of particles of 0.2 μm or more was 20 particles / sheet.
[0074]
Comparative Example 1
The W silicide powder produced in the same manner as in Example 1 was filled into a graphite mold and then set in a hot press apparatus, and a pressure of 34.3 MPa was applied in a vacuum of 5 × 10 −4 Pa or less. However, it was densified and sintered under the condition of 1350 ° C. × 5 h. Thereafter, the atmosphere was cooled to room temperature without applying pressureless heat treatment.
[0075]
This W silicide sintered body was machined to a desired target size, and the sputtered surface was finished by polishing. The surface roughness of the sputtered surface after finishing was 0.03 μm in Ra. In this way, two W silicide targets (diameter 127 mm × thickness 6 mm) were produced.
[0076]
One of the two W silicide targets thus obtained was subjected to Raman spectroscopic analysis, and the Raman spectrum was measured in the same manner as in Example 1. As a result, in the W silicide target of Comparative Example 1, the average value of the shift amount Δν of the free Si peak is 4.40 cm−1, and the average value of the residual stress σ obtained from each shift amount Δν is 1100 MPa. The average half-width of the Si peak was 14.23 cm-1.
[0077]
Next, after bonding the other W silicide target to a Cu backing plate, it was set in a sputtering apparatus (SH-550 manufactured by ULVAC), and a W silicide film was formed in the same manner as in Example 1. As a result, the number (average value) of 0.2 μm or more particles present in the W silicide film was 72 / sheet.
[0078]
Comparative Example 2
For the W silicide sintered body that has been subjected to densification and sintering under the same conditions as in Comparative Example 1, the pressing force was removed while maintaining the vacuum atmosphere following the pressurizing and heating step. Heat treatment was performed under the condition of ℃ × 5h. Thereafter, the atmosphere was cooled to room temperature.
[0079]
The W silicide sintered body that has undergone the above-described pressureless heat treatment was machined to a desired target size, and the sputtered surface was further polished by polishing. The surface roughness of the sputtered surface after finishing was 0.04 μm in Ra. In this way, two W silicide targets (diameter 127 mm × thickness 6 mm) were produced.
[0080]
One of the two W silicide targets thus obtained was subjected to Raman spectroscopic analysis, and the Raman spectrum was measured in the same manner as in Example 1. As a result, in the W silicide target of Comparative Example 2, the average value of the shift amount Δν of the free Si peak was 3.33 cm −1, and the average value of the residual stress σ obtained from each shift amount Δν was 832 MPa. The average half-width of the Si peak was 11.20 cm-1.
[0081]
Next, after bonding the other W silicide target to a Cu backing plate, it was set in a sputtering apparatus (SH-550 manufactured by ULVAC), and a W silicide film was formed in the same manner as in Example 1. As a result, the number (average value) of 0.2 μm or more particles present in the W silicide film was 33 particles / sheet.
[0082]
Comparative Example 3
For the W silicide sintered body that has been subjected to densification and sintering under the same conditions as in Comparative Example 1, the pressing force is removed while maintaining the vacuum atmosphere following the pressurizing and heating step. Heat treatment was performed under the condition of ℃ × 3h. Thereafter, the atmosphere was cooled to room temperature.
[0083]
The W silicide sintered body that has undergone the above-described pressureless heat treatment was machined to a desired target dimension, and the sputtered surface was further finished by CMP. The surface roughness of the sputtered surface after finishing was 0.03 μm in Ra. In this way, two W silicide targets (diameter 127 mm × thickness 6 mm) were produced.
[0084]
One of the two W silicide targets thus obtained was subjected to Raman spectroscopic analysis, and the Raman spectrum was measured in the same manner as in Example 1. As a result, in the W silicide target of Comparative Example 3, the average value of the shift amount Δν of the free Si peak is 3.45 cm −1, and the average value of the residual stress σ obtained from each shift amount Δν is 863 MPa. The average half-width of the Si peak was 12.11 cm-1.
[0085]
Next, after bonding the other W silicide target to a Cu backing plate, it was set in a sputtering apparatus (SH-550 manufactured by ULVAC), and a W silicide film was formed in the same manner as in Example 1. As a result, the number (average value) of particles of 0.2 μm or more existing in the W silicide film was 55 / sheet.
[0086]
Comparative Example 4
For the W silicide sintered body that has been subjected to densification and sintering under the same conditions as in Comparative Example 1, the pressure is removed while maintaining the vacuum atmosphere following the pressure heating step, and 1400 Heat treatment was performed under the condition of ℃ × 3h. Thereafter, the atmosphere was cooled to room temperature. Since the obtained W silicide sintered body was heat-treated immediately below the melting point of Si, the free Si phase was eluted and could not be molded as a target.
[0087]
Comparative Example 5
With respect to the Mo silicide sintered body that was subjected to densification sintering under the same conditions as in Example 5, the pressure was removed while maintaining the vacuum atmosphere following the pressurization and heating step. Heat treatment was performed under the condition of ℃ × 5h. Thereafter, the atmosphere was cooled to room temperature.
[0088]
The Mo silicide sintered body that had undergone the above-described pressureless heat treatment was machined to a desired target size, and the sputtered surface was further polished by polishing. The surface roughness of the sputtered surface after finishing was Ra, 0.05 μm. In this way, two Mo silicide targets (diameter 127 mm × thickness 6 mm) were produced.
[0089]
One of the two Mo silicide targets thus obtained was subjected to Raman spectroscopic analysis, and the Raman spectrum was measured in the same manner as in Example 1. As a result, in the Mo silicide target of Comparative Example 5, the average value of the shift amount Δν of the free Si peak is 3.07 cm-1, and the average value of the residual stress σ obtained from each shift amount Δν is 767 MPa. The average half-width of the Si peak was 10.21 cm-1.
[0090]
Next, after bonding the other Mo silicide target to a Cu backing plate, it was set in a sputtering apparatus (SH-550 manufactured by ULVAC), and a Mo silicide film was formed in the same manner as in Example 5. As a result, the number (average value) of particles of 0.2 μm or more existing in the Mo silicide film was 45 / sheet.
[0091]
Comparative Example 6
For the Ta silicide sintered body that was subjected to densification and sintering under the same conditions as in Example 6, the applied pressure was removed while maintaining the vacuum atmosphere following the pressurization and heating step. Heat treatment was performed under the condition of ℃ × 3h. Thereafter, the atmosphere was cooled to room temperature.
[0092]
The Ta silicide sintered body subjected to the above-described pressureless heat treatment was machined to a desired target size, and the sputtered surface was further finished by CMP. The surface roughness of the sputtered surface after finishing was 0.08 μm in Ra. In this way, two Ta silicide targets (diameter 127 mm × thickness 6 mm) were produced.
[0093]
One of the two Ta silicide targets thus obtained was subjected to Raman spectroscopic analysis, and the Raman spectrum was measured in the same manner as in Example 1. As a result, in the Ta silicide target of Comparative Example 6, the average value of the shift amount Δν of the free Si peak was 3.50 cm-1, and the average value of the residual stress σ obtained from each shift amount Δν was 875 MPa. The average half-width of the Si peak was 16.54 cm-1.
[0094]
Next, after bonding the other Ta silicide target to the Cu backing plate, it was set in a sputtering apparatus (SH-550 manufactured by ULVAC), and a Ta silicide film was formed in the same manner as in Example 6. As a result, the number (average value) of particles of 0.2 μm or more existing in the Ta silicide film was 85 / sheet.
[0095]
Table 1 summarizes the heat treatment conditions of each silicide target according to Examples 1 to 6 and Comparative Examples 1 to 6 described above, the results of Raman spectroscopic analysis, and the number of particles when a silicide film is formed using them. .
[0096]
[Table 1]

As apparent from Table 1, according to the metal silicide targets according to Examples 1 to 6, the residual stress of the free Si phase was set to 750 MPa or less and the half-width of the free Si peak of the Raman spectrum was set to 10 cm -1 or less. It can be seen that the number of particles generated is significantly reduced as compared with Comparative Examples 1 to 3 and Comparative Examples 5 to 6.
[0097]
Furthermore, it was confirmed that the yield and quality of these semiconductor devices and LCD elements were improved when the electrodes and wirings of the semiconductor devices and LCD elements were formed using the silicide targets according to the above-described embodiments. That is, high-quality electronic components can be obtained with a high yield.
[0098]
【The invention's effect】
As described above, according to the sputtering target of the present invention, the generation of particles due to the residual stress of the free Si phase can be significantly suppressed. Accordingly, it is possible to greatly improve the quality of the metal silicide thin film used as wiring, electrodes, element constituent films and the like of electronic parts typified by semiconductor elements and liquid crystal display elements.
[Brief description of the drawings]
FIG. 1 is a diagram showing a shift state of a Si peak of a Raman spectrum for obtaining a residual stress of a free Si phase in a sputtering target of the present invention.
FIG. 2 is a diagram for explaining a method for measuring a residual stress of a free Si phase in a sputtering target of the present invention.

Claims (13)

General formula: MSi _x
(Wherein M represents at least one element selected from W, Mo, Ta, Ti, Zr, Hf, Ni and Co, and x represents a number satisfying 2 ≦ x ≦ 4)
Sintering a metal silicide powder represented by the following under pressure to produce a densified metal silicide sintered body;
Subsequent to the sintering step, after heat treatment at a temperature of 1000 to 1380 ° C. with the pressure applied to the metal silicide sintered body being released, cooling to room temperature,
And a step of processing the metal silicide sintered body that has undergone the heat treatment step into a desired target shape. In the manufacturing method of the sputtering target of Claim 1 ,
The pressure sintering step is performed by holding a pressure of 24.5-34.3 MPa to the metal silicide powder in a vacuum at a temperature of 1200-1380 ° C. for a predetermined time. Target manufacturing method. In the manufacturing method of the sputtering target of Claim 1 or Claim 2 ,
The said heat processing process is performed by hold | maintaining the said metal silicide sintered compact at the temperature of 1000-1200 degreeC in a vacuum for 2 to 10 hours, The manufacturing method of the sputtering target characterized by the above-mentioned. A sputtering target manufactured by the method for manufacturing a sputtering target according to any one of claims 1 to 3,
A sputtering target having a microstructure including a metal silicide phase formed in a chain shape and a free Si phase existing discontinuously in a gap between the metal silicide phases . The sputtering target according to claim 4, wherein
  The residual stress of the free Si phase is the amount of shift of the free Si peak in the Raman spectrum of Raman spectroscopy (Δν (unit: cm ^-1 ))
  Formula: (2.5 × 109 × △ ν) × 10 ^-1   [Pa]
  The sputtering target characterized by being 750 MPa or less as a value computed based on the stress conversion formula represented by these. The sputtering target according to claim 5, wherein
  The sputtering target, wherein the variation of the residual stress of the free Si phase as a whole of the target is within 20%. The sputtering target according to any one of claims 4 to 6,
  The half-width of the free Si peak in the Raman spectrum of Raman spectroscopy is 10 cm. ^-1 A sputtering target characterized by: A metal silicide film formed using the sputtering target according to any one of claims 4 to 7 . Wirings, characterized in that it consists of a metal silicide film formed using the sputtering target according to any one of claims 4 to 7. An electrode comprising a metal silicide film formed using the sputtering target according to any one of claims 4 to 7 . An electronic component comprising a metal silicide film formed using the sputtering target according to any one of claims 4 to 7 . The electronic component according to claim 11 , wherein
An electronic component characterized by being a semiconductor element. The electronic component according to claim 11 , wherein
An electronic component which is a liquid crystal display element.

Images