JP2001303243A - Sputtering target, method for manufacturing the same and electronic parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the generation of particles caused by the state of the tissue and its working surface (more particularly its sputtering surface, etc.), in a metal silicide target. SOLUTION: This sputtering target has the fine structure containing the metal silicide phase which is composed of the metal silicide expressed by MSix (where, M denotes at least one element selected from W, Mo, Ta, Ti Zr and Co and x denotes a number ranging from 2 to 4) and is formed to a chain form and the Si phase which is formed by bonding of excessive Si particles and exist discontinuously in the spacings of the metal silicide phase. This metal silicide has hardness below 1,300 Hv in Vickers hardness and is in the state in which residual stress is released in accordance with this lower hardness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a sputtering target made of metal silicide, a method for manufacturing the same, and an electronic component having a metal silicide thin film formed using the same.

[0002]

2. Description of the Related Art In electronic components such as semiconductor devices and liquid crystal display devices, W, Mo, Ta, Ti, Zr, and the like are used as materials for forming wirings and electrodes and as element constituent films.
A refractory metal silicide compound such as Co is used. In particular, the delay of electric signals has become a problem due to the narrowing of electrodes and wirings accompanying high integration and high density of semiconductor elements. However, metal silicide thin films such as W and Mo having low resistance have low resistance. It is useful as a material for forming simple electrodes and wirings. The metal silicide thin film is also effective for suppressing electromigration.

As a method of forming a thin film made of a silicide compound of a refractory metal such as W or Mo (WSi ₂ , MoSi _2, etc.), a sputtering method and a CVD method are mentioned as typical film forming methods. Membrane productivity, stability,
From the viewpoint of manufacturing cost and the like, a sputtering method is particularly generally used.

When a metal silicide thin film as described above is formed by a sputtering method, it is necessary to prepare a sputtering target using metal silicide. Here, as a method of manufacturing a general sputtering target,
Melting method using electron beam (EB) melting, etc., or hot press (HP) or hot isostatic press (HIP)
A powder sintering method using such a method is known.

When a metal silicide target is produced, a powder sintering method is generally used because the composition of a metal silicide film to be formed is easily controlled (for example, Japanese Patent Application Laid-Open No. H5-214523). Gazette). Specifically, first, a high melting point metal (M) powder such as W or Mo and silicon (S)
and i) powder, the atomic ratio of Si is mixed in a 2 to 4, perform the synthesis reaction of the metal silicide (MSi ₂₎ heat treated to the mixed powder. After further adding silicon (Si) powder to the obtained metal silicide powder,
A metal silicide target is manufactured by applying pressure sintering under high pressure in a high vacuum by applying HP, HIP, or the like.

[0006]

The above-mentioned conventional metal silicide target has a form in which a fine Si phase is arranged in a gap between MSi ₂ phases. However,
In the conventional powder firing method, a sintered body is prepared by adding Si powder to a synthetic metal silicide powder.
_In the sintered bodies of _{2.2 to 3,} the volume ratio of the Si phase is in the range of 8 to 25%, and the amount of the Si phase is much smaller than that of the MSi ₂ phase. Therefore, it is not easy to spread the Si phase all around the MSi ₂ phase, and the silicide target having a non-uniform structure such as the MSi ₂ phases aggregating or the local Si phase is present. turn into.

[0007] The difference in the melting point of the high melting point metal (M) also greatly affects the target performance. For example, WS
Each melting point of i ₂ , MoSi ₂ , TiSi ₂ and TaSi ₂ is 2165
℃, 2030 ℃, 1540 ℃, 2200 ℃. As described above, since MSi ₂ having a melting point greatly different from that of Si having a melting point of 1414 ° C. is pressure-sintered just below the eutectic temperature, thermally stable MSi 2 is obtained.
Sintering does not proceed between the _two particles, and the bonding force between the particles is weakened. For this reason, pores remain in the silicide target, resulting in insufficient densification.

When a sputter film is formed by using the above-mentioned conventional silicide target, bonding between particles is broken by Ar irradiation energy at the time of sputtering, and destruction or missing from the sputtered surface of the target starting from a defect portion. Will happen. These cause the generation of particles.
The particles are fine particles generated from the target, for example, particles having a diameter of about 0.2 to 10 μm. When such particles are mixed into the formed thin film, they cause a short circuit between wirings and open defects of wirings, thereby lowering the production yield of electronic components such as semiconductor elements and liquid crystal display elements. Therefore, it is strongly desired to significantly reduce the amount of generated particles.

Further, as a cause of the generation of particles,
In addition to the above-mentioned non-uniformity of the target structure and insufficient densification, a minute processing defect phase, surface state, and residual stress generated when the target material (sintered metal silicide) obtained by sintering is finished by machining. And the like.

[0010] That is, the conventional grinding finish is a method of shaving off a workpiece with hard abrasive grains of a grinding wheel rotating at a high speed. A hard and brittle metal silicide sintered body is processed by such a method. In this case, a chipping phenomenon occurs in which the granular chips are inevitably scattered from the processing surface. This is caused by the fact that minute cracks occur on the processed surface due to the contact stress of the abrasive grains during grinding, and after the abrasive grains pass, the shoulder portion of the crack is pushed up by rapid release of the stress and detached as fragments. It is considered something.

Normally, when processing a brittle material, the depth of cut per abrasive grain or the load is appropriately increased.
Cracks are included in the local stress field induced by the abrasive grains, and processing is promoted by accumulating micro-fractures of the material. Therefore, on the ground surface of the silicide target, for example, the sputter surface, a large number of grinding streaks, falling holes, minute cracks, and the like are generated. Further, residual stress is generated on the processed surface.
When a sputter film is formed by using such a silicide target, destruction or missing occurs starting from a defective portion, and particles are generated.

Japanese Patent Application Laid-Open No. H11-256322 discloses that a target material is composed of stoichiometric refractory metal silicide MSi ₂ and pure silicon Si as a target for reducing the generation of particles from an early stage of use. The relative density, which is the ratio of the true density of the target material to the theoretical density calculated on the assumption, is 100% or more, and the half value of the (101) peak of the MSi ₂ phase in the X-ray diffraction intensity measurement of the sputtering surface of the target material. A metal silicide target having a width of 0.7 deg or less is described.

[0013] The metal silicide target described in the above-mentioned publication aims to reduce the initial particles by reducing the strain, and therefore defines the half width in the X-ray diffraction intensity measurement. The manufacturing method described in this publication describes that a target after processing is subjected to a heat treatment at a temperature of 800 to 1250 ° C. in order to remove distortion after mirror processing.

The present invention has been made to address such a problem, and it is intended to prevent the generation of particles due to the internal structure and internal state of a silicide target and the state of a processed surface (particularly, a sputtered surface). It is an object of the present invention to provide a sputtering target that can significantly suppress the sputtering, and a method for manufacturing such a sputtering target. Further, it is another object of the present invention to provide an electronic component with improved production yield and quality by using such a sputtering target.

[0015]

The inventors of the present invention have conducted various studies in order to suppress the generation of particles considered to be caused by the internal structure or internal state of the silicide target. It was found that the release of the internal residual stress was one of the factors generating particles.

Particles due to release of internal residual stress can be greatly suppressed by releasing the residual stress of the target in advance, and the release state of the residual stress can be judged from the hardness of the target. The present inventors have found. That is, by releasing the residual stress of the silicide target in advance and reducing the hardness of the silicide target based on the release of the residual stress, it is possible to greatly suppress particles due to the above-described release of the stress.

Further, in processing the target surface, a processing method capable of reducing residual stress is applied, and a surface state having a small residual stress is set based on the processing method. It can be further reduced. Regarding the target surface (sputtered surface), large or uneven unevenness is one of the causes of particle generation. By reducing such unevenness, the amount of generated particles can be further reduced. Becomes

[0018] The present invention has been made based on these findings, as the sputtering target of the present invention as set forth in claim 1, general formula: MSi _x (where, M is W, Mo, Ta, Ti, Zr, Hf, Ni
And at least one element selected from Co and x is 2
The number of the metal silicide phases is in the range of 4 to 4). The metal silicide phase formed in a chain and an excess of Si particles are combined with each other. In a sputtering target having a microstructure containing a continuously existing Si phase, the target has a Vickers hardness of 1300 Hv or less.

According to the metal silicide target having such hardness, the amount of particles generated due to the above-mentioned stress release can be significantly reduced. Further, in the sputtering target of the present invention, it is preferable that the variation in Vickers hardness of the entire target is within ± 20%.

The sputtering target of the present invention is further characterized in that the sputtering surface of the target has a surface roughness represented by a maximum height Ry of 2 μm or less. The surface roughness of the sputtering surface of the target is, as described in claim 5, the maximum height Ry.
In addition, the surface roughness represented by the distortion value Rsk is preferably in the range of -3 to +3. With such a surface state, it is possible to further reduce the generation amount of particles including particles caused by the state of the sputtered surface.

According to a sixth aspect of the present invention, there is provided a method of manufacturing a sputtering target according to the sixth aspect of the present invention, wherein the step of manufacturing a target material comprising the metal silicide is performed. And the target material exceeds 1250 ° C and 1400 ° C
A heat treatment is performed at the following temperature to reduce the hardness of the target material to 1300 Hv or less in Vickers hardness, and a step of processing the target material to a desired size.

An electronic component according to the present invention has an electrode or a wiring including at least a part of a metal silicide thin film formed by using the above-described sputtering target according to the present invention. I have. Specific examples of such electronic components include a semiconductor element and a liquid crystal display element.

[0023]

Embodiments of the present invention will be described below.

[0024] The sputtering target of the present invention have the general formula: MSi _x ... (1) (in the formula, M W, Mo, Ta, Ti, Zr, Hf, Ni
And at least one element selected from Co and x is 2
(Indicating a number in the range of ~ 4).

Here, the value of x is basically set from the amount of Si constituting MSi ₂ and the amount of excess Si. If the value of x is less than 2, the desired metal silicide (MSi ₂ ) thin film cannot be obtained with good reproducibility.
On the other hand, if the value of x exceeds 4.0, the excess Si amount is too large, so that the resistance value becomes high, which may adversely affect the element. More preferably, the value of x is in the range of 2.5 to 3.2.

According to the metal silicide target of the present invention, based on the above-mentioned excess Si, excessive S is formed in the gaps of the MSi ₂ phase (metal silicide phase) formed in a chain.
It has a microstructure in which Si phases formed by combining i-particles are present discontinuously. The presence discontinuously Si phase in the gap between the MSi ₂ phase, it is possible to increase the bonding state of the MSi ₂ phase.

In the sputtering target of the present invention, the metal silicide containing excess Si (MS
The hardness of a metal silicide target composed of i ₂ + Si) and having a microstructure including an MSi ₂ phase and a Si phase,
The Vickers hardness is set to 1300Hv or less.

Here, the hardness of the target specified in the present invention is a value measured by the following method. That is, as shown in FIG. 1, for example, the center part (position 1) of the disk-shaped target and the circumference passing through the center part are equally divided.
Positions near the outer circumference on four straight lines (positions 2 to 9) and part 1
The test pieces having a length of 10 mm and a width of 10 mm were sampled from a position at a distance of 1/2 (positions 10 to 17), and the hardness of the sputtered surface of these 17 test pieces was measured under the following conditions for measuring Vickers hardness. And a value obtained by averaging these measured values. Further, the variation of the Vickers hardness of the entire target, which will be described later, is calculated from the maximum value and the minimum value of the Vickers hardness obtained from the 17 test pieces described above, as follows: ｛(maximum value−minimum value) / (maximum value + minimum value) ) Indicates a value obtained based on the formula of｝ × 100.

The Vickers hardness in the present invention indicates a value measured using a Vickers hardness tester under the conditions of a test load of 500 gf, a time of 15 s and room temperature. Since the metal silicide target of the present invention has a high-hardness MSi ₂ phase and a low-hardness Si phase in the microstructure as described above, the Vickers hardness is measured with one test piece. Ten points are measured at different locations, and the average value is taken as the hardness of each test piece.

One of the causes of the generation of particles in the metal silicide target is that the internal residual stress of the target is released during sputtering. That is, the residual stress generated in the process of manufacturing the target material or the process of processing into a desired shape (including the finishing of the surface) is released by the Ar irradiation energy at the time of sputtering. Missing occurs.
Foreign matter generated by destruction or lack of the sputtered surface mixes as particles into the formed metal silicide film, causing a problem.

The number of particles generated based on the above-mentioned stress release can be greatly reduced by releasing the residual stress of the metal silicide target in advance and suppressing the release of stress due to sputter energy. The residual stress of the target is, for example, a hot press (H
P) A target material made of metal silicide, which is produced by sintering by a treatment or hot isostatic pressing (HIP) treatment, is heat-treated at a temperature of more than 1250 ° C. and 1400 ° C. or less after sintering. Softens the surface, i.e. the Vickers hardness of the final target is 13
Dramatically reduced (less stress) by setting it below 00Hv
can do. Also, instead of this heat treatment, a similar effect can be obtained by maintaining the substrate at a predetermined temperature in a non-pressurized state during cooling after the HP treatment or the HIP treatment.

The temperature of the heat treatment for releasing the stress (softening)
If the temperature exceeds 1400 ° C., free Si is eluted, which adversely affects the target tissue. On the other hand, at a temperature of 1250 ° C. or less, a sufficient stress relief effect cannot be obtained. In other words,
The metal silicide target cannot be sufficiently softened. The heat treatment temperature is more preferably higher than 1250 ° C. and not higher than 1350 ° C., more preferably in the range of 1300 to 1350 ° C.

As described above, the hardness of the metal silicide target subjected to the heat treatment for releasing the stress is lower than that before the heat treatment. Then, by lowering the hardness of the metal silicide target, it is possible to greatly suppress the generation of particles due to the release of the residual stress during sputtering. The effect of suppressing particles based on the decrease in hardness can be significantly obtained by setting the hardness of the metal silicide target to 1300 Hv or less in Vickers hardness.

That is, according to the metal silicide target having a Vickers hardness of 1300 Hv or less based on the above-described measurement method, it is possible to greatly suppress the generation of particles due to the release of stress during sputtering. In order to further enhance the effect of suppressing particles, the hardness of the metal silicide target is preferably 1100 Hv or less in Vickers hardness, and more preferably 1000 Hv or less.

Further, the hardness of the metal silicide target is preferably within ± 20% as a variation in Vickers hardness of the entire target. The variation in Vickers hardness is defined by the method described above. In this way, by reducing the hardness of the entire target on average, it is possible to suppress the variation in the amount of particles generated by each part in the target. That is, the amount of generated particles can be suppressed as a whole of the metal silicide target, and a higher quality metal silicide thin film can be obtained. The variation in Vickers hardness of the target as a whole is preferably within ± 15%, more preferably within ± 10%.

In the sputtering target (metal silicide target) of the present invention, the surface roughness of the sputtering surface is preferably 2 μm or less in terms of the maximum height Ry.
Also, the surface roughness of the sputtered surface, in addition to the maximum height Ry,
More preferably, the surface roughness represented by the distortion value Rsk is in the range of -3 to +3.

That is, the magnitude of the residual stress on the target surface greatly depends on the surface processing method.
In the method of scraping the workpiece with the hard abrasive grains of the grinding wheel rotating at high speed as in the conventional surface grinding, a large number of grinding streaks, falling holes, minute cracks, etc. occur on the machined surface, Residual stress occurs.

On the other hand, by machining the target material to a desired size and then finishing the surface by lapping, polishing, CMP or the like, the processed surface can be smoothed and the target surface (particularly, It is possible to reduce the residual stress on the sputtered surface). In other words, the surface roughness of the sputtering surface is the maximum height R
By processing the target surface so that y is 2 μm or less and distortion value Rsk is in the range of −3 to +3, it is possible to suppress the generation of residual stress itself. Therefore,
By setting the surface roughness of the sputtered surface in the above-described range, the number of particles generated during sputter deposition can be further reduced.

Further, the large irregularities existing on the sputter surface itself cause the generation of particles. In other words, particles caused by the state of the sputtering surface of the metal silicide target generate abnormal discharge based on the presence of relatively large irregularities, and the abnormal discharge causes the tip of the convex portion to fall off to generate a massive foreign substance, or This is because the abnormal discharge itself generates fine dust.
Therefore, it is possible to suppress the generation of particles due to the state of the sputtered surface by removing the large irregularities that cause the abnormal discharge as described above.

Here, the maximum height Ry represents the maximum height of unevenness existing on the surface. Specifically, only the reference line L is extracted from the roughness curve in the direction of the average line, and the height (Y) of the extracted portion from the average line to the highest peak is calculated.
p) and the depth to the lowest valley bottom (Yv) (Ry = Yp)
+ Yv). By setting the maximum height Ry to 2 μm or less, that is, by removing large irregularities from the sputter surface, it is possible to further suppress the generation of particles. The maximum height Ry of the sputtering surface is
More preferably, it is 1.5 μm or less, more preferably 1 μm or less.

Incidentally, in the above-mentioned Japanese Patent Application Laid-Open No. 5-215523, an arithmetic average roughness R is used as one index of the surface processing state.
It is described that a is set to 0.05 μm or less. However, since the surface roughness Ra is a value obtained by averaging a roughness curve, it cannot be determined from the Ra value even if there are some large irregularities on the sputtered surface. Therefore, the above-described abnormal discharge alone cannot suppress the above abnormal discharge with good reproducibility.

The distortion value Rsk is a value representing the distortion of the surface, and is divided at equal intervals between the highest peak and the lowest valley of a roughness curve called an amplitude distribution curve, and two parallel lines are formed. The ratio of the number (n) of data existing in the area within the area (n) to the total number of data (N) is plotted on the horizontal axis, and the height direction (Y) of the roughness curve is plotted on the vertical axis. And is expressed by the following equation (2).

[0043]

(Equation 1) When the above-mentioned distortion value Rsk shows a positive value, it indicates that there are many peaks on the whole, and when it shows a negative value, it indicates that there are many dents below. When such a distortion value Rsk exceeds +3 or is smaller than -3, the number of generated particles due to the state of the sputtering surface increases based on the unevenness of the unevenness. In other words, by setting the distortion value Rsk of the sputtering surface in the range of −3 to +3, it is possible to further reduce the number of generated particles. The distortion value Rsk of the sputtering surface is in the range of -1 to +1;
More preferably, the range is -0.5 to +0.5.

The surface roughness of the sputtered surface specified in the present invention is a value obtained by measuring each surface roughness of the sputtered surface of the sputtering target, that is, the maximum height Ry and the distortion value Rsk by the following methods. . As shown in FIG. 1, for example, the center (position 1) of a disk-shaped target,
10 mm in length and 10 mm in width from the positions near the outer circumference (positions 2 to 9) and half the distance (positions 10 to 17) on four straight lines that divide the circumference evenly through the center 10mm
, And the surface roughness of each of the 17 sputtered surfaces of the test pieces is measured by a conventional stylus method, and these measured values are averaged. These average values are used as the surface roughness of the sputtered surface.

The sputtering target comprising the metal silicide of the present invention can be manufactured, for example, as follows.

That is, first, M element powder as a raw material and S
i powder and 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 mixing state. Such mixed powder subjected to heat treatment at a temperature corresponding to the M element, to synthesize the metal silicide _{(MSi x = MSi 2 + Si} x-2).

Next, the calcined body of the metal silicide is pulverized into a metal silicide powder. The obtained metal silicide powder is filled into a molding die made of, for example, graphite and hot-pressed. Alternatively, HI is added to the metal silicide powder.
P processing is performed. The obtained metal silicide powder may be added as a raw material powder by adding Si powder for composition adjustment. However, in order to homogenize the target structure, the metal silicide powder obtained by the synthesis reaction is used alone. Is preferably used as a raw material powder.

Next, the target material (metal silicide sintered body) obtained in the sintering step is subjected to a heat treatment for softening, in other words, a heat treatment for releasing the residual stress. This heat treatment is performed at 1250 ° C in a vacuum of 7 × 10 ^-2 Pa or less.
It is preferred to carry out at a temperature exceeding 1400 ° C. As described above, when the heat treatment temperature exceeds 1400 ° C, free S
i elutes. On the other hand, if the temperature is lower than 1250 ° C., it cannot be sufficiently softened. The heat treatment time is preferably about 2 to 10 hours. More preferably 3-7 hours, even more
Desirably, 4 to 6 hours.

Thereafter, the target material that has been heat-treated is machined to have a desired target size, and the sputtered surface is finished. As described above, it is preferable to apply lapping, polishing, CMP, or the like to the surface processing of the sputtering surface. In these finishing processes, the amount of polishing is reduced in the order of lapping, polishing and CMP, so that the fineness of the finished surface (sputtered surface) is improved and the residual stress is also reduced. These can be used in combination. In the surface finishing step, as described above, the surface roughness of the sputtered surface is 2 μm at the maximum height Ry.
m or less, and the distortion value Rsk is preferably in the range of -3 to +3.

[0050]

Next, specific examples of the present invention will be described.

Example 1 First, a high-purity W powder having a maximum particle size of about 10 μm,
Si powder having a Si / W atomic ratio (x) of 2.
The resulting mixture was mixed in a ball mill replaced with high-purity Ar gas for 48 hours. 1200 ° C
A silicide reaction heat treatment was performed under the conditions of × 1 h, and the obtained calcined body was pulverized under the conditions of 96 hours to obtain a W silicide powder. After filling this W silicide powder into a graphite mold, it is set in a hot press and heat-treated at 1380 ° C × 5h while applying a pressure of 34 MPa in a vacuum of 5 × 10 ⁻⁴ Pa or less. For densification sintering.

Next, the W silicide sintered body (target material) was subjected to a softening heat treatment at 1300 ° C. × ² hours in a vacuum of 5 × 10 ⁻² Pa.

Thereafter, the heat-treated W silicide sintered body was machined to a desired target size, and the sputtered surface was finished by polishing. After finishing, the surface roughness of the sputtered surface is adjusted by Tealer Hobson S4C.
The maximum height Ry was measured by the stylus method using
1.08 μm and distortion value Rsk was −0.5.

The W silicide target (127 mm in diameter × 6 mm in thickness) thus obtained was bonded to a Cu backing plate and set in a sputtering apparatus. 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 as follows: Ar pressure = 0.2 Pa, Ar flow rate = 80 scc
m, 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 determined. As a result, the number of particles of 0.2 μm or more was 5 / sheet.

Further, a W silicide target prepared under the same manufacturing conditions as described above was prepared, and the hardness of this target was measured using a Vickers hardness tester (Shimadzu microhardness meter: HMV-2000) according to the method described above. It was measured. As a result, Vickers hardness of W silicide target is 950H
and the Vickers hardness of the target as a whole was 5%.

Example 2 The W silicide sintered body produced under the same conditions as in Example 1 was subjected to a softening heat treatment at 1250 ° C. × 2 h in a vacuum of 5 × 10 ⁻² Pa, Machined to the target dimensions of
Polishing) to obtain a W silicide target. The surface roughness of this sputtered surface is the maximum height Ry
1.57 μm, and the distortion value Rsk was −0.8.

Using the W silicide target (127 mm diameter × 6 mm thickness) obtained in this way, a W silicide film is formed under the same conditions as in Example 1, and the W silicide film having a thickness of 0.2 μm or more existing in the W silicide film is formed. When the number of particles (average value) was examined, the number of particles having a particle size of 0.2 μm or more was 10 / sheet.

Further, a W silicide target prepared under the same manufacturing conditions as described above was prepared, and the hardness of the target was measured according to the method described above. As a result, Vickers hardness of W silicide target is 1020Hv
The variation in Vickers hardness of the entire target was 10%.

Comparative Examples 1 and 2 After the W silicide sintered body produced under the same conditions as in Example 1 was machined to a desired target size, the sputtered surface was finished by grinding to obtain a W silicide target (comparative). Example 1). Regarding the surface roughness of the sputtered surface, the maximum height Ry was 3.12 μm and the distortion value Rsk was +4.2. Separately, the sputtered surface was finished under the same conditions as in Example 1 to obtain a W silicide target (Comparative Example 2).
The surface roughness of this sputtered surface was almost the same as in Example 1, the maximum height Ry was 1.23 μm, and the distortion value Rsk was -0.8. Note that none of the W silicide targets according to Comparative Examples 1 and 2 was subjected to a softening heat treatment.

Using each W silicide target (127 mm diameter × 6 mm thickness) obtained in this way, a W silicide film is formed under the same conditions as in Example 1, and the thickness of 0.2 μm or more existing in the W silicide film is obtained. The number of particles (average value) was examined. As a result, in Comparative Example 1, the number of particles of 0.2 μm or more was 72 / sheet, and in Comparative Example 2, the number of particles of 0.2 μm or more was 60 / sheet.

Further, W silicide targets manufactured under the same manufacturing conditions as those described above were prepared, and the hardness of these targets was measured according to the method described above. As a result, the V Vickers hardness of the W silicide target of Comparative Example 1 was 1490 Hv, and the variation in Vickers hardness of the entire target was 12%. Comparative Example 2
Hardness of W silicide target is 1390Hv
The variation in Vickers hardness of the entire target was 25%.

Example 3 First, a high-purity Mo powder having a maximum particle size of about 20 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 2.7. Was mixed for 48 hours in a ball mill replaced with high-purity Ar gas. The mixed powder was subjected to a silicide reaction heat treatment at 1150 ° C. × 1 h, and the obtained calcined body was pulverized under a condition of 96 h to obtain a Mo silicide powder. After filling this Mo silicide powder into a graphite molding die, it was set in a hot press device, and 5 × 1
1350 while applying a pressure of 34 MPa in a vacuum of 0 ^-4 Pa or less
Densification sintering was performed under a heat treatment condition of 5 ° C. × 5 hours.

Then, the Mo silicide sintered body (target material) was heated at 1200 ° C. for ² hours in a vacuum of 5 × 10 ^-2 Pa.
The softening heat treatment was performed under the following conditions.

Thereafter, the heat-treated sintered body of Mo silicide was machined to a desired target size, and the sputtered surface was finished by polishing. When the surface roughness of the sputtered surface after finishing was measured by the above-described method, the maximum height Ry was 1.28 μm, and the distortion value Rsk was −0.2.

The thus obtained Mo silicide target (127 mm in diameter × 6 mm in thickness) was bonded to a Cu backing plate and set in a sputtering apparatus.
Using such a sputtering apparatus, 5 inch Si
A 200 nm thick Mo silicide film was formed on the wafer. The sputtering conditions were as follows: Ar pressure = 0.2 Pa, Ar flow rate = 80 sccm, Power = 0.5 kW. Sputter deposition is 24 sheets of S
Repeatedly for i-wafer, Mo on each Si wafer
The number of particles of 0.2 μm or more existing in the silicide film was examined, and the average value was obtained. As a result, the number of particles of 0.2 μm or more was 19 / sheet.

Further, a Mo silicide target manufactured under the same manufacturing conditions as the above was prepared, and the hardness of this target was measured according to the method described above. As a result, the Vickers hardness of the Mo silicide target was 1020.
Hv, and the variation in Vickers hardness of the entire target was 10%.

Example 4 The Mo silicide sintered body manufactured under the same conditions as in Example 3 was subjected to a softening heat treatment at 1350 ° C. × 4 h in a vacuum of 5 × 10 ⁻² Pa, , And the sputtering surface was finished by CMP to obtain a Mo silicide target. Regarding the surface roughness of the sputtered surface, the maximum height Ry was 1.18 μm, and the distortion value Rsk was −0.5.

Using the Mo silicide target (diameter 127 mm × thickness 6 mm) thus obtained, a Mo silicide film was formed under the same conditions as in Example 3, and a Mo silicide film having a thickness of 0.2 μm or more existing in the Mo silicide film was formed. When the number of particles (average value) was examined, the number of particles having a size of 0.2 μm or more was 14 / sheet.

Further, a Mo silicide target prepared under the same conditions as the above-mentioned manufacturing conditions was prepared, and the hardness of this target was measured according to the method described above. As a result, the Vickers hardness of the Mo silicide target was 998H
and the variation in Vickers hardness of the entire target was 14%.

Comparative Examples 3 and 4 After the sintered body of Mo silicide produced under the same conditions as in Example 3 was machined to a desired target size, the sputtered surface was finished by grinding to obtain a Mo silicide target (comparative). Example 3). Regarding the surface roughness of the sputtered surface, the maximum height Ry was 2.1 μm and the distortion value Rsk was −4.1. Separately from this, a Mo silicide target was prepared by finishing the sputtered surface under the same conditions as in Example 3 (Comparative Example 4).
And The surface roughness of the sputtered surface was almost the same as in Example 3, the maximum height Ry was 1.31 μm, and the distortion value Rsk was -1.5. Note that none of the Mo silicide targets according to Comparative Examples 3 and 4 was subjected to a softening heat treatment.

Using each of the Mo silicide targets (diameter 127 mm × thickness 6 mm) obtained as described above, a Mo silicide film was formed under the same conditions as in Example 3, and the Mo silicide film existing in the Mo silicide film was not less than 0.2 μm. The number of particles (average value) was examined. As a result, in Comparative Example 3, the number of particles of 0.2 μm or more was 174 / sheet, and in Comparative Example 4, the number of particles of 0.2 μm or more was 85 / sheet.

Further, Mo silicide targets prepared under the same conditions as those described above were prepared, and the hardness of these targets was measured according to the method described above. As a result, the Vickers hardness of the Mo silicide target of Comparative Example 3 was 1320 Hv, and the variation of the Vickers hardness of the entire target was 18%. The Vickers hardness of the Mo silicide target of Comparative Example 4 was 14
At 00 Hv, the Vickers hardness variation of the entire target was 25%.

Example 5 First, high-purity Ta powder having a maximum particle size of about 20 μm and Si powder having a maximum particle size of 30 μm or less were blended so that the atomic ratio (x) of Si / Ta became 2.6. Was mixed for 48 hours in a ball mill replaced with high-purity Ar gas. This mixed powder was subjected to a silicide reaction heat treatment at 1250 ° C. × 0.5 h, and the obtained calcined body was pulverized under a condition of 96 h to obtain a Ta silicide powder. After filling this Ta silicide powder into a graphite mold, the Ta silicide powder was set in a hot press and
While applying a pressure of 34 MPa in a vacuum of × 10 ^-4 Pa or less, 1
Densification sintering was performed under the heat treatment conditions of 400 ° C. × 5 hours.

Next, the Ta silicide sintered body (target material) was heated at 1350 ° C. for ² hours in a vacuum of 5 × 10 ^-2 Pa.
The softening heat treatment was performed under the following conditions.

Thereafter, the heat-treated Ta silicide sintered body was machined to a desired target size, and the sputtered surface was finished by polishing. When the surface roughness of the sputtered surface after finishing was measured by the above-described method, the maximum height Ry was 1.14 μm and the distortion value Rsk was +2.3.

The Ta silicide target (diameter 127 mm × thickness 6 mm) thus obtained was bonded to a Cu backing plate and set in a sputtering apparatus.
Using such a sputtering apparatus, 5 inch Si
A Ta silicide film having a thickness of 200 nm was formed on the wafer. The sputtering conditions were as follows: Ar pressure = 0.2 Pa, Ar flow rate = 80 sccm, Power = 0.5 kW. Sputter deposition is performed sequentially on 24 Si wafers, and T
The number of particles having a particle size of 0.2 μm or more in the silicide film a was examined, and the average value was obtained. As a result, the number of particles of 0.2 μm or more was 10 / sheet.

Further, a Ta silicide target manufactured under the same manufacturing conditions as described above was prepared, and the hardness of the target was measured according to the method described above. As a result, the Vickers hardness of the Ta silicide target was 1270
Hv, and the variation in Vickers hardness of the entire target was 15%.

Example 6 A Ta silicide sintered body produced under the same conditions as in Example 5 was subjected to a softening heat treatment at 1300 ° C. × 4 h in a vacuum of 5 × 10 ⁻² Pa, , And the sputtering surface was finished by CMP to obtain a Ta silicide target. Regarding the surface roughness of the sputtered surface, the maximum height Ry was 1.05 μm, and the distortion value Rsk was +1.4.

Using the Ta silicide target (diameter 127 mm × thickness 6 mm) thus obtained, a Ta silicide film was formed under the same conditions as in Example 5, and the thickness of 0.2 μm or more existing in the Ta silicide film was obtained. When the number of particles (average value) was examined, the number of particles of 0.2 μm or more was 16 / sheet.

Further, a Ta silicide target prepared under the same manufacturing conditions as described above was prepared, and the hardness of this target was measured according to the method described above. As a result, the Vickers hardness of the Ta silicide target was 1250.
Hv, and the Vickers hardness variation of the target as a whole was 5%.

Comparative Examples 5 and 6 After a Ta silicide sintered body produced under the same conditions as in Example 5 was machined to a desired target size, the sputtered surface was finished by grinding to obtain a Ta silicide target (Comparative Example). Example 5). Regarding the surface roughness of the sputtered surface, the maximum height Ry was 2.1 μm and the distortion value Rsk was +5.4. Separately from this, a Ta silicide target was prepared by finishing the sputtered surface under the same conditions as in Example 5 (Comparative Example 6).
And The surface roughness of the sputtered surface was almost the same as in Example 5, the maximum height Ry was 1.41 μm, and the distortion value Rsk was +0.9. Note that none of the Ta silicide targets according to Comparative Examples 5 and 6 was subjected to softening heat treatment.

Using each Ta silicide target (diameter 127 mm × thickness 6 mm) thus obtained, a Ta silicide film was formed under the same conditions as in Example 5, and a thickness of 0.2 μm or more existing in the Ta silicide film was obtained. The number of particles (average value) was examined. As a result, in Comparative Example 5, the number of particles of 0.2 μm or more was 108 / sheet, and in Comparative Example 6, the number of particles of 0.2 μm or more was 88 / sheet.

Further, Ta silicide targets prepared under the same conditions as those described above were prepared, and the hardness of these targets was measured according to the method described above. As a result, the Vickers hardness of the Ta silicide target of Comparative Example 5 was 1574 Hv, and the variation of the Vickers hardness of the entire target was 35%. The Vickers hardness of the Ta silicide target of Comparative Example 6 was 15
At 00 Hv, the variation in Vickers hardness of the entire target was 32%.

Further, it was confirmed that the yield and quality of the semiconductor element and the liquid crystal display element can be improved by forming the electrodes and the wiring of the semiconductor element and the liquid crystal display element using the silicide targets according to the above-described embodiments. did. That is, high-quality electronic components can be obtained with a high yield.

[0085]

As described above, according to the sputtering target of the present invention, the generation of particles due to the residual stress of the target can be largely suppressed, and furthermore, the particles due to the shape of the sputtered surface can be reduced. Can also be suppressed. Therefore, it is possible to greatly improve the quality of a metal silicide thin film used as a wiring, an electrode, an element constituent film, or the like of an electronic component typified by a semiconductor element or a liquid crystal display element.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a method for measuring hardness and surface roughness in a sputtering target of the present invention.

Continued on the front page (72) Inventor Yasuo Takasaka 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside the Toshiba Yokohama office (72) Inventor Naomi Fujioka 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Toshiba Corporation Inside Yokohama Office (72) Inventor Yukinobu Suzuki 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture F-term in Toshiba Yokohama Office (reference) 4K029 BA35 BA52 BD02 CA05 DC05 DC09 DC12 4M104 BB20 BB21 BB24 BB25 BB26 BB27 BB28 DD40 HH20 5F103 AA08 BB22 DD30 GG02 GG03 HH03 LL14 RR04 RR06

Claims (10)

[Claims] 1. A general formula: MSi _x (where M is W, Mo, Ta, Ti, Zr, Hf, Ni
And at least one element selected from Co and x is 2
The number of the metal silicide phases is in the range of 4 to 4). The metal silicide phase formed in a chain and an excess of Si particles are combined with each other. A sputtering target having a microstructure including a continuous Si phase, wherein the target has a Vickers hardness of 1300 Hv or less. 2. The sputtering target according to claim 1, wherein the Vickers hardness of the target is 1100 Hv.
A sputtering target characterized by the following. 3. The sputtering target according to claim 1, wherein a variation in Vickers hardness of the entire target is ± 20.
%. 4. The sputtering target according to claim 1, wherein the sputtering surface of the target has a surface roughness represented by a maximum height Ry of 2 μm or less. Sputtering target. 5. The sputtering target according to claim 1, wherein the sputtering surface of the target has a surface roughness represented by a distortion value Rsk in a range of −3 to +3. A sputtering target characterized by the above-mentioned. 6. The method for manufacturing a sputtering target according to claim 1, wherein: a step of producing a target material made of the metal silicide; and a heat treatment of the target material at a temperature of more than 1250 ° C. and 1400 ° C. or less; A method for manufacturing a sputtering target, comprising: a step of setting the hardness of the target material to 1300 Hv or less in Vickers hardness; and a step of processing the target material to a desired size. 7. The method for manufacturing a sputtering target according to claim 6, wherein, in the step of processing the target material, the surface roughness of the sputtered surface has a maximum height Ry of 2 μm or less and a distortion value Rsk of −3 to +3. A method of manufacturing a sputtering target, comprising processing a surface of the target material so as to fall within a range. 8. An electronic component, comprising: an electrode or a wiring including at least a part of a metal silicide thin film formed by using the sputtering target according to claim 1. 9. The electronic component according to claim 8, wherein the electronic component is a semiconductor device. 10. The electronic component according to claim 8, wherein the electronic component is a liquid crystal display element.