JP4470036B2 - Sputtering target, method for producing the same, and thin film produced using the same - Google Patents

Description

  The present invention relates to a sputtering target made of metal, ceramics or a composite thereof, a thin film produced using the sputtering target, and a method for producing the sputtering target.

  In recent years, a liquid crystal display (hereinafter abbreviated as LCD) has been adopted as a display device for computers and portable terminals. Among these liquid crystal displays, an active matrix LCD having a thin film transistor (hereinafter abbreviated as TFT) has a wide viewing angle and can be displayed close to a cathode ray tube system. Collecting.

  In such a TFT type LCD, a method of forming a thin film by sputtering and patterning it into a predetermined shape is used as a method for forming a TFT electrode material.

  In this sputtering process, in recent years, in order to improve productivity and reduce the tact time, a technique of applying a higher power than usual and shortening the sputtering process time by increasing the deposition rate has been adopted. . In the patterning step, an etching method using a wet process that can be similarly processed in a large amount is employed.

  It is known that when the density of the sputtering target used in this sputtering process is low, cracks are generated during sputtering or there is a problem of yield reduction due to generation of particles. As a countermeasure against this, increasing the density of the sputtering target has been proposed (see, for example, Patent Documents 1, 2, and 3). However, a target with a relative density of 96% or more has many residual pores, and the sputtering conditions at a high power density in recent years are insufficient to solve the particle problem caused by arcing or splashing.

  On the other hand, it has been proposed to reduce the generation of particles by refining crystal grains of a sputtering target (see, for example, Patent Documents 4 and 5).

  Patent Document 4 proposes having a fine structure with an average particle diameter of 10 μm and a maximum particle diameter of 40 μm or less, and Patent Document 5 proposes having a fine structure with an average particle diameter of 10 μm or less. However, in such a method, since elements other than the target main constituent element precipitated at the grain boundary in the sintering process segregate as one large lump, arcing or splash is required under the sputtering conditions at high power density in recent years. It is not enough to solve the particle problem caused by the occurrence.

  In order to increase the density of the sputtering target, a method has been proposed in which a press-molded compact is sintered and further rolled or forged while being heated (see, for example, Patent Documents 3 and 5). In Patent Document 3, it is necessary to perform press molding for forming a molded body, heat sintering for sintering, and rolling or forging while heating. In patent document 5, it is necessary to perform the heat sintering which produces a pre-sintered body, and also hot plastic working. However, such a wide variety of processes causes a decrease in productivity and an increase in cost due to an increase in tact time.

  The thin film formed by sputtering is patterned with an etchant by a wet process. At this time, since it is difficult to control the etching rate of the thin film, in Patent Document 6, patterning with a first etching solution, Furthermore, measures are taken by patterning with the second etching solution and etching method in two stages, but such a complicated process causes a decrease in productivity and an increase in cost due to an increase in tact time.

JP-A-9-3635 (pages 1 to 3)

JP 2002-327264 A (page 3) JP-A-9-59768 (pages 2 and 3) JP 2000-45066 A (pages 1 to 3) Japanese Patent No. 3244167 (pages 1 and 2) JP 2000-31111 A (pages 1 to 3)

  The present invention has been made by paying attention to such circumstances, and the purpose thereof is a sputtering target capable of obtaining a thin film that is less prone to arcing in the sputtering process and that has excellent patterning processability, and the like. It is an object of the present invention to provide a manufacturing method and to provide a thin film excellent in patterning processability formed by using this sputtering target.

  In view of the current situation as described above, the present inventors have studied on the assumption that arcing occurs due to the following reasons. That is, if an element other than the main constituent element of the target is present in the sputtering target, the sputtering rate of the portion where such an element is present is different from the sputtering rate of the target composition. , Forming protrusions. Concentration of the applied electric field at the time of sputtering occurs in the formed protrusion, and arcing occurs due to this concentration. When the power at the time of sputtering is larger than normal conditions, the target surface is melted by arcing and scattered to adhere to the substrate as a splash.

  Usually, the sputtering target is used while flowing cooling water from the back side of the backing plate in order to cool the surface of the sputtering target exposed to plasma. At this time, if an element other than the target main constituent element is present in the sputtering target, the thermal conductivity of the portion where such an element exists is different from the thermal conductivity of the target composition, so that the cooling efficiency is partially deteriorated. . Also in this case, a rapid temperature rise occurs partially due to the deterioration of the cooling efficiency, the target surface melts and scatters and adheres to the substrate as a splash.

  The effect of such arcing and the presence of elements other than the target main constituent elements that cause splash has a size effect, and when it exists in the sputtering target in a large shape, it may cause arcing or splash. It has been known. That is, a portion where an element other than a large target main constituent element is present forms a large protrusion due to an uncut portion, which causes arcing due to electric field concentration. In addition, a portion where elements other than the large target main constituent element are present causes an inhibition of the cooling effect and causes splash.

  Furthermore, the present inventors have studied based on the following assumptions as factors affecting the patterning processability of the sputtered thin film. That is, the etching phenomenon of the thin film proceeds as the etchant preferentially dissolves the grain boundary portion of the thin film and the crystal grains are detached from the grain boundary portion. Elements other than the original target composition are likely to be precipitated at the grain boundary portion, which further promotes the progress of etching.

  As a result of these studies, during the sintering process of the sintered body to be the sputtering target, grain growth is arbitrarily promoted, and as a result, elements other than the main constituent elements of the sputtering target contained in a trace amount are grains of the sintered body. It has been found that it is possible to prevent the occurrence of arcing or splash during sputtering by preventing concentration and precipitation at the boundary and diffusing within the grains.

  In addition, since the element concentration other than the main constituent element in the sputtering thin film is reflected in the element concentration other than the main constituent element in the sputtering target, by controlling the element concentration other than the main constituent element in the sputtering target, It has been found that the etching rate of the sputtered thin film, that is, the patterning processability can be controlled, and the problem has been solved.

  That is, the present invention relates to a sputtering target made of a metal, which includes Mo, Cd, Cr, Fe, Mn, Ni, Ca, Co, Cu, Mg, Pb, Ti, Zn, Si, Al ( However, the total concentration of the sputtering target (excluding main constituent elements) is 50 ppm or more and 1000 ppm or less.

  Further, the present invention is selected from the group consisting of Cr, Mo, Al, Ag, Ti, Cu, Ni, In, Co, Ir, Ru, Ta, Nb, Pt, Au, V, Zn, Zr, Pd and W. A sputtering target comprising one or more elements selected from the group consisting of Mo, Cd, Cr, Fe, Mn, Ni, Ca, Co, Cu, Mg, Pb, Ti, Zn, and Si. The total concentration of Al (excluding main constituent elements of the sputtering target) is 50 ppm or more and 1000 ppm or less.

  In the sputtering target, the total concentration of Fe, Co, and Si (excluding the main constituent elements of the sputtering target) is preferably 20 ppm or more and 200 ppm or less, and the concentration of Fe is 10 ppm or more, More preferably, it is 150 ppm or less.

  Further, the present invention is a sputtering target made of Mo, and the total of Cd, Cr, Fe, Mn, Ni, Ca, Co, Cu, Mg, Pb, Ti, Zn, Si, and Al of the sputtering target. It is a sputtering target characterized in that the concentration is 50 ppm or more and 1000 ppm or less. In the sputtering target, the total concentration of Fe, Co, and Si is preferably 20 ppm or more and 200 ppm or less, and the Fe concentration Is more preferably 10 ppm or more and 150 ppm or less.

  On the other hand, the average particle size of the sputtering target of the present invention is preferably 13 μm or more and 200 μm or less, and the relative density thereof is preferably 98% or more.

In addition, the sputtering target of the present invention is preferably manufactured by a hot isostatic press (HIP) method. In particular, a sputtering target made of Mo has a molding temperature of 1100 ° C. ˜1800 ° C., molding pressure of 1000 kg / cm ² or more, and holding time of 1 to 20 hours are preferable.

The sputtering target manufacturing method of the present invention is a sputtering target manufacturing method characterized in that a metal, particularly Mo or an Mo alloy, is manufactured by a hot isostatic press (HIP) method. A method for producing a sputtering target, which is produced by a hot isostatic press (HIP) method at a molding temperature of 1100 ° C. to 1800 ° C., a molding pressure of 1000 kg / cm ² or more, and a holding time of 1 to 20 hours. It is a manufacturing method of the sputtering target which makes it.

  Furthermore, the thin film of this invention is a thin film formed using said sputtering target. In particular, the thin film of the present invention provides a sputtering thin film in which there is no deterioration in thin film characteristics such as resistivity, there is no patterning residue due to particles generated during sputtering, and the etching rate can be easily controlled.

  The main constituent element of the sputtering target of the present invention is an element that constitutes the original sputtering target constituent material other than a small amount of additive elements and impurity elements. For example, in the case of a sputtering target made of a MoW alloy, the main constituent element is the main constituent element. Constituent elements are Mo and W. Further, the sputtering target of the present invention may contain inevitable impurities such as C of about 50 ppm, O of about 500 ppm, and N of about 10 ppm.

  According to the sputtering target of the present invention, in particular, the Mo sputtering target of the present invention, it is possible to produce a sputtered thin film having low resistivity without arcing during sputtering even in sputtering with high-density discharge power. It is possible to obtain a thin film excellent in workability at the time, and for example, it is possible to form an excellent thin film for forming a TFT electrode for a liquid crystal display.

  The present invention is described in further detail below.

  A sputtering target made of a metal, ceramics, or a composite thereof according to the present invention is manufactured by the following method.

  In the sputtering target of the present invention, in order to arbitrarily adjust the additive element concentration of the raw material powder, a predetermined element is added and mixed in order to uniformly disperse, and then the mixed raw material powder is sintered. It can be manufactured using the obtained sintered body. Moreover, the thin film of this invention can be manufactured by forming into a film with a sputtering device using this obtained sputtering target.

  Hereinafter, an example in the case of manufacturing these sintered bodies by the HIP method will be described. In addition, although these sintered compacts can be manufactured also by methods, such as a vacuum baking method, an atmospheric baking method, a hot press method, for example, manufacturing by a HIP method is desirable. The obtained sintered body can be machined to a predetermined size as it is, but can also be processed to a predetermined size by a method such as forging or rolling.

  Hereinafter, although an example in the case of manufacturing a Mo sputtering target and a MoW alloy sputtering target will be described, when manufacturing a sputtering target made of another single metal or an alloy, Mo, Cd, Cr, Fe, Mn, Elements obtained by removing main constituent elements of the sputtering target from Ni, Ca, Co, Cu, Mg, Pb, Ti, Zn, Si, and Al are used.

  When producing a Mo sputtering target, a Mo powder is prepared, and Cd, Cr, Fe, Mn, Ni, Ca, Co, Cu, Mg, Pb, Ti are prepared in order to adjust this to an arbitrary additive element concentration. One or more elements selected from Zn, Si, and Al are added and mixed. In the case of producing a MoW alloy sputtering target that is an alloy, similarly, an alloy powder of MoW alloy, or a powder of Mo and W is prepared, and Cd, Cr, Fe, One or more elements selected from Mn, Ni, Ca, Co, Cu, Mg, Pb, Ti, Zn, Si, and Al are added and mixed.

  As an additive element at this time, Fe is preferable as an additive element for facilitating processing control during patterning, Fe, Co, and Si are more preferable, and Cd, Cr, Fe, Mn, Ni, Ca, Co, Cu, and Mg are more preferable. Pb, Ti, Zn, Si, and Al are particularly preferable. Further, as the additive element concentration, it is essential that the total concentration of Cd, Cr, Fe, Mn, Ni, Ca, Co, Cu, Mg, Pb, Ti, Zn, Si, and Al is 50 ppm or more and 1000 ppm or less. In addition, the total concentration of Fe, Co, and Si is preferably 20 ppm or more and 200 ppm or less, and the Fe concentration is more preferably 10 ppm or more and 150 ppm or less. When the Fe concentration is 10 ppm or more and 150 ppm or less, there is a correlation between the Fe concentration and the etching rate. When the total concentration of Fe, Co, and Si is 20 ppm or more and 200 ppm or less, Fe, Co, and Si There is a strong correlation between the total concentration and the etching rate, and the total concentration of Cd, Cr, Fe, Mn, Ni, Ca, Co, Cu, Mg, Pb, Ti, Zn, Si, Al is 50 ppm or more, Since the etching rate is 1000 ppm or less, there is a particularly strong correlation between the etching rate and the total concentration of Cd, Cr, Fe, Mn, Ni, Ca, Co, Cu, Mg, Pb, Ti, Zn, Si, and Al and the etching rate. The control in the patterning process is particularly easy.

  Here, the total concentration of Cd, Cr, Fe, Mn, Ni, Ca, Co, Cu, Mg, Pb, Ti, Zn, Si, and Al is 50 ppm or less, or the total concentration of Fe, Co, and Si is 20 ppm or less. If the Fe concentration is 10 ppm or less, a sufficient etching rate cannot be obtained in a thin film obtained using the sputtering target, and Cd, Cr, Fe, Mn, Ni, Ca, Co, Cu, Mg, Pb, Ti, If the total concentration of Zn, Si, and Al is 1000 ppm or more, or the total concentration of Fe, Co, and Si is 200 ppm or more, or the concentration of Fe is 150 ppm or more, the etching rate is too high and control becomes difficult. If the concentration of the additive element is 1000 ppm or more, problems such as an increase in resistivity occur in the thin film obtained using the sputtering target, and sufficient thin film characteristics cannot be obtained.

  The additive element is added to the raw material powder by mixing the material (additive) consisting of the additive element with the raw material powder. The additive and the raw material powder are mixed by a general ball mill mixing method. A mixing method using a shaker mixer, a mixing method using a V-shaped blender device, and the like can be mentioned, but the method is not limited thereto.

  Further, by using a medium made of a predetermined element as a medium used at the time of mixing (for example, a mixed medium such as a ball in a ball mill mixing method), the concentration of the element in the raw material powder can be increased. For example, by using Fe media, the concentration of Fe can be arbitrarily increased. As an adjustment method at this time, it is possible to adjust to a predetermined concentration by appropriately changing the size of the medium, the density of the medium, the shape of the medium, the rotation speed of the mixing container, the mixing time, and the like. In this method, the Mo powder raw material is sequentially made up of predetermined materials, that is, Cd, Cr, Fe, Mn, Ni, Ca, Co, Cu, Mg, Pb, Ti, Zn, Si, and Al. By performing ball mill mixing using a medium, the concentration of each element can be arbitrarily adjusted to a predetermined concentration. Since the Mo powder used here preferably has good sintering characteristics, the powder particle size is preferably 10 μm or less, more preferably 7 μm or less, and particularly preferably 5 μm or less, but is limited to the above powder particle size is not. Further, it is known that the particle diameter of Mo powder having a purity of 99.9% or more, which is usually readily available and can be used in terms of price, is 10 μm or less. In addition to Mo, Cd, Cr, Fe, Mn, Ni, Ca, Co, Cu, Mg, Pb, Ti, Zn, Si, and Al are used as elements to be added to adjust the etching rate. Can be procured easily, can be purchased relatively inexpensively, and can be procured as a medium used in the ball mill mixing method. Moreover, the media used here are not limited to a single composition, and for example, media made of an alloy such as CrNi, FeZn, CoSi, and AlTi can also be used. Further, in the method of adjusting the concentration by ball mill mixing using media of each material, it is preferable because the material of Fe, Co, Si is easy to adjust the concentration, and the material of Fe adjusts the concentration. It is particularly preferred because it is easier. As media for additive elements used, media of Mo, Cd, Cr, Fe, Mn, Ni, Ca, Co, Cu, Mg, Pb, Ti, Zn, Si, and Al are selected. It is not limited to media to be used.

A molded body is manufactured by molding the raw material powder whose concentration is adjusted as described above by the CIP method. In the case of producing a molded body by a pressing method, after a predetermined mold is filled with powder, press molding is performed at a pressure of 100 kg / cm ² or more using a powder press machine. When forming a molded body by the CIP method, a raw material powder is filled in a rubber mold of a predetermined size. After this, the mouth portion of the rubber mold is sealed with a rubber stopper. Then, it shape | molds by applying a pressure of 2500 kg / cm < ² > or more using a CIP apparatus. The molded body after the CIP process is processed into a predetermined shape. After that, it is put into a metallic container such as SUS, Fe, Mo, Nb, Ta, Ti, etc., and after sufficient deaeration treatment, sealing is performed. The material of the metallic container used here is arbitrarily selected depending on the temperature and pressure conditions of the subsequent HIP process, but is not limited to the above materials.

The molded body sealed with the metal container is placed in a predetermined HIP apparatus and subjected to HIP processing under conditions for obtaining a sufficient density. For example, when Mo HIP is performed, in order to obtain a sufficient density, sintering is performed at a temperature of 1100 to 1800 ° C., a pressure of 1000 kg / cm ² or more, and a holding time of 1 to 20 hours. The HIP conditions are preferably a temperature of 1200 to 1800 ° C., a pressure of 1100 kg / cm ² or more, and a holding time of 2 hours or more, more preferably 1300 to 1800 ° C., a pressure of 1200 kg / cm ² or more and a holding time of 2 hours or more. When the HIP temperature is set to 1100 ° C. or higher, it is difficult to sufficiently increase the density below this temperature. When the HIP temperature is set to 1800 ° C. or lower, the temperature rise / fall time is long and the productivity is improved by increasing the tact time. This is because problems arise.

If the holding time is 1 hour or more, it is difficult to improve the density sufficiently if the holding time is less than 1 hour, and if it is less than 20 hours, the sintering time takes a long time, and there is a problem in productivity due to an increase in takt time This is because it occurs. The reason why the pressure is 1000 kg / cm ² or more is that it is difficult to sufficiently improve the density if it is less than 1000 kg / cm ² . In order to cause grain growth in the sintering by HIP and diffuse impurities into coarse grains, a temperature of 1100 ° C. or higher, a pressure of 1000 kg / cm ² or higher, and a holding time of 1 hour or longer are required. 1200 ° C. or more, pressure 1100 kg / cm ² or more, holding time 2 hours or more, more preferably temperature 1300 ° C. or more, pressure 1200 kg / cm ² or more, holding time 2 hours or more, but not limited to the above conditions. In addition, the average particle diameter of the obtained sintered body is sufficient with the minimum grain growth in which impurities are sufficiently diffused in the grains, which leads to shortening of the sintering time, that is, shortening of the tact time. Therefore, from the above reason, 13 to 200 μm is preferable, 13 to 100 μm is more preferable, 13 to 50 μm is particularly preferable, and 13 to 30 μm is more particularly preferable. If the average particle size is less than 13 μm, the diffusion of impurities in the grains due to grain growth is insufficient, and if the condition is larger than 200 μm and promotes grain growth, the sintering time takes a long time, and the takt time increases to increase productivity. This is because problems arise. In addition, when the average particle size is 200 μm or more, specific dependency appears in the sputtering direction for each particle, which causes a problem that the film thickness distribution of the sputtered film becomes non-uniform.
Furthermore, in the present invention, an element other than the main constituent elements of the sputtering target is added to the sputtering target for the purpose of controlling the patterning processability of the sputtered film produced using the sputtering target. This facilitates the precipitation of elements other than the main constituent elements of the sputtering target at the grain boundaries, which can easily cause arcing or splash, and can suppress the occurrence of arcing or splash by promoting grain growth. It becomes.

  The sintered body thus produced is processed into a predetermined size, and then bonded to a backing plate as needed to be used as a sputtering target.

When producing a Mo _x W _y (0 <x <100, 0 <y <100) sintered body using the method as described above, the HIP condition for obtaining a sufficient density is a temperature of 1100 to 1800 ° C. The pressure is preferably 1000 kg / cm ² or more and the holding time is 1 to 20 hours. The sintered body thus produced is processed into a predetermined size, and then bonded to a backing plate as needed to be used as a sputtering target.

When producing an Al _x Ti _y (0 <x <100, 0 <y <100) sintered body using the method as described above, the HIP condition for obtaining a sufficient density is a temperature of 400 to 600 ° C. The pressure is preferably 1000 kg / cm ² or more and the holding time is 1 to 20 hours. The sintered body thus produced is processed into a predetermined size, and then bonded to a backing plate as needed to be used as a sputtering target.

When producing a Mo _x Cr _y (0 <x <100, 0 <y <100) sintered body using the method as described above, the HIP condition for obtaining a sufficient density is a temperature of 900 to 1400 ° C. The pressure is preferably 1000 kg / cm ² or more and the holding time is 1 to 20 hours. The sintered body thus produced is processed into a predetermined size, and then bonded to a backing plate as needed to be used as a sputtering target.

When producing an A _x Z _y O _z (A: Al, Z: Zn, 0 <x <100, 0 <y <100, 0 <z <100) sintered body using the method as described above, As HIP conditions for obtaining a sufficient density, a temperature of 800 to 1200 ° C., a pressure of 1000 kg / cm ² or more, and a holding time of 1 to 20 hours are preferable. The sintered body thus produced is processed into a predetermined size, and then bonded to a backing plate as needed to be used as a sputtering target.

In the case of producing a sintered body using the above-described method, I _x T _y O _z (I: In, T: Sn, 0 <x <100, 0 <y <100, 0 <z <100), As HIP conditions for obtaining a sufficient density, a temperature of 800 to 1100 ° C., a pressure of 1000 kg / cm ² or more, and a holding time of 1 to 20 hours are preferable. The sintered body thus produced is processed into a predetermined size, and then bonded to a backing plate as needed to be used as a sputtering target.

When the Mo _x Cr _y (SiO ₂ ) _z (0 <x <100, 0 <y <100, 0 <z <100) sintered body is manufactured using the method as described above, a sufficient density is obtained. As HIP conditions for this, a temperature of 800 to 1400 ° C., a pressure of 1000 kg / cm ² or more, and a holding time of 1 to 20 hours are preferable. The sintered body produced in this way is processed into a predetermined size and then bonded to a backing plate as needed to be used as a target.

  Confirmation of the additive element concentration and average particle diameter of the sputtering target thus prepared can be carried out by the following method.

  Samples for additive element concentration analysis, average particle size measurement, and density measurement are cut out from several places of the prepared sintered body. The sample for measuring the concentration of the added element is placed in a beaker containing acetone and cleaned using an ultrasonic cleaner. Subsequently, it is transferred to a container containing pure water and similarly subjected to ultrasonic cleaning. Thereafter, after the drying process is performed by a heat dryer, impurity analysis is performed by an inductively coupled plasma analyzer (ICP) or an inductively coupled plasma mass spectrometer (ICP-MS). The average value of the additive element concentration obtained from the analysis result is taken as the additive element concentration of the sputtering target prepared from the sintered body.

  On the other hand, the sample cut out for measuring the average particle diameter is similarly subjected to a cleaning process, and then the sample is polished and subjected to an etching process to selectively etch the grain boundaries. The sample in which the grain boundary can be observed in this way is photographed with an optical microscope, and this is used to determine the total area and number of particles to be measured using image analysis software (Win ROOF, manufactured by MITANI CORPORATION), By dividing the total area of the measured particles by the number of measured particles, an average area of one particle was obtained. The diameter when the area is equivalent to a circle is defined as the average particle diameter. Furthermore, let the average value of the average particle diameter of several places measured similarly be an average particle diameter of a sputtering target.

  The sample cut out for density measurement was subjected to density measurement by the Archimedes method, and the average value was taken as the density of the sputtering target.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited only to these Examples.

Example 1
A Mo powder having a powder size of 4 μm or less is prepared. The total concentration of Cd, Cr, Fe, Mn, Ni, Ca, Co, Cu, Mg, Pb, Ti, Zn, Si, and Al in this powder is 28 ppm, and the total concentration of Fe, Co, and Si is 14 ppm, Fe The concentration of was 6 ppm. An appropriate amount of this powder and Fe mixing media were filled in a resin pot and mixed for 10 hours at a rotation speed of 70 rpm using a ball mill mixer. Thereafter, element concentration analysis of the obtained powder other than the target main constituent elements was performed, and the Fe concentration was 13 ppm. Subsequently, an appropriate amount of this powder and a mixing medium made of a CoSi alloy were filled in a resin pot, and mixed for 8 hours at a rotation speed of 70 rpm using a ball mill mixer. Thereafter, the additive element concentration of the obtained powder was analyzed, and the Co concentration was 7 ppm and the Si concentration was 3 ppm. Subsequently, in the same manner as the above method, the material of the media is sequentially changed to a medium of a single composition metal or alloy of Cd, Cr, Mn, Ni, Ca, Cu, Mg, Pb, Ti, Zn, and Al. Then, a ball mill mixing treatment was performed. Thereafter, the additive element concentration analysis of the obtained powder was performed, and the total concentration of Cd, Cr, Fe, Mn, Ni, Ca, Co, Cu, Mg, Pb, Ti, Zn, Si, and Al was 63 ppm. . A compact was prepared by the CIP method using the Mo powder with the additive element concentration adjusted in this manner. CIP conditions were 3000 kg / cm ² and molding was performed by applying a pressure of 30 seconds. The molded body was processed into a predetermined size by a dry processing method, and then a sintered body was manufactured by the HIP method. The HIP conditions are as follows.
Sintering temperature: 1400 ° C
Pressure: 2000 kg / cm ²
Holding time: 2 hours Temperature rising rate: 200 ° C./h
Atmosphere: Argon When the density of the sintered body thus obtained was measured by Archimedes method, it was 10.17 g / cm ³ (relative density: 99.5%). A part of the sintered body was cut out to obtain a sample for analysis. The sample for measuring the concentration of the added element is placed in a beaker containing acetone and cleaned using an ultrasonic cleaner. Subsequently, it is transferred to a container containing pure water and similarly subjected to ultrasonic cleaning. Then, after the drying treatment was performed with a heat dryer, the concentration of the additive element was measured with an inductively coupled plasma analyzer (ICP) or an inductively coupled plasma mass spectrometer (ICP-MS).

  In order to observe the particle size, a sample is cut into 10 mm squares, embedded in an acrylic resin, and cured. This was followed by rough polishing with abrasive paper and mirror polishing with slurry using a rotary polishing apparatus. This was followed by etching with nitric acid, and sufficient washing and drying to prepare a sample for particle size evaluation. The sample thus prepared was observed with an optical microscope, and then a photograph was taken with a polaroid camera. Image analysis processing was performed using the photographed photograph, and the average particle diameter was determined from the area and the number of grains.

  The sample cut out for density measurement was subjected to density measurement by the Archimedes method, and the average value was taken as the density of the sputtering target.

  The sintered body thus produced is processed into a size of 5 inches × 7 inches × 10 mmt by a wet processing method. This was bonded to an oxygen-free copper backing plate with indium solder to obtain a sputtering target for sputtering.

Using this sputtering target, a glass substrate of 50 cm square under conditions of ultimate vacuum of 1 × 10 ⁻⁶ Torr, room temperature conditions, discharge power of 8 W / cm ² , Ar pressure of 0.5 Pa, and substrate-target distance of 30 mm using a sputtering apparatus. A film having a thickness of 150 nm was applied to make a sample for resistivity measurement and etching rate measurement. Further, a continuous discharge test for 20 hours was performed under the same sputtering conditions, and the total number of arcing times at this time was detected with a micro arc monitor (manufactured by Landmark Technology). The resistivity was measured at five locations in a plane with a four-end needle resistivity measuring device, and the average value was taken as the resistivity.

  The etching rate was measured by the following procedure.

  A resist is applied on the Mo thin film formed on the substrate, and prebaking is performed in an oven. Subsequently, the resist is exposed to a predetermined shape by an exposure apparatus, and then development and post-baking are performed. Thereafter, the thin film is etched by being immersed in an etchant for a predetermined time. Thereafter, the resist is removed. Thus, the depth of the groove part which etched the thin film by which the patterning process was performed with the contact-type level | step difference measuring apparatus is measured. The etching rate was calculated from this depth and immersion time. The etchant used was a mixed solution of sulfuric acid, hydrogen peroxide, and distilled water, which is generally known as an etching solution for Mo, and was etched under conditions adjusted to a constant temperature.

(Example 2)
In the same manner as in Example 1, a sintered body was prepared in the same manner as in Example 1 using Mo powder adjusted to an additive element concentration different from that in Example 1, and then in the same manner as in Example 1. Samples for analysis were cut out from the sintered body, and the density, additive element concentration, and average particle diameter were measured. A sputtering target was produced from this sintered body by the same method as in Example 1, and sputtering was performed under the same conditions as in Example 1, and the resistivity, arcing frequency, and etching rate were measured.

(Examples 3 and 4)
Using a Mo powder adjusted to a predetermined additive element concentration by the same method as in Example 1, the sintering temperature is controlled to be higher than that in Example 1 by the same method as in Example 1 to produce a sintered body. After that, a sample for analysis was cut out from the sintered body in the same manner as in Example 1, and the density, additive element concentration, and average particle diameter were measured. A sputtering target was produced from this sintered body by the same method as in Example 1, and sputtering was performed under the same conditions as in Example 1, and the resistivity, arcing frequency, and etching rate were measured.

(Examples 5 and 6)
A sintered body in which the sintering temperature is controlled to be higher than those in Examples 2 and 3 by the same method as in Example 1 using Mo powder adjusted to a predetermined additive element concentration by the same method as in Example 1. After the sample was prepared, a sample for analysis was cut out from the sintered body in the same manner as in Example 1, and the density, additive element concentration, and average particle size were measured. A sputtering target was produced from this sintered body by the same method as in Example 1, and sputtering was performed under the same conditions as in Example 1, and the resistivity, arcing frequency, and etching rate were measured.

(Comparative Examples 1 and 2)
A sintered body in which the sintering temperature is controlled to be lower than those in Examples 1 and 2 in the same manner as in Example 1 using Mo powder adjusted to a predetermined additive element concentration by the same method as in Example 1. After the sample was prepared, a sample for analysis was cut out from the sintered body in the same manner as in Example 1, and the density, additive element concentration, and average particle size were measured. A sputtering target was produced from this sintered body by the same method as in Example 1, and sputtering was performed under the same conditions as in Example 1, and the resistivity, arcing frequency, and etching rate were measured.

(Comparative Examples 3, 4, 5, 6)
The same method as in Example 1 after producing a sintered body under the same conditions and method as in Examples 2 and 3 using Mo powder adjusted to a predetermined additive element concentration by the same method as in Example 1. The sample for analysis was cut out from the sintered body, and the density, additive element concentration, and average particle diameter were measured. A sputtering target was produced from this sintered body by the same method as in Example 1, and sputtering was performed under the same conditions as in Example 1, and the resistivity, arcing frequency, and etching rate were measured.

(Comparative Examples 7 and 8)
After the sintered body was manufactured under the temperature condition higher than Comparative Examples 1 and 2 and lower than Example 1 using Mo powder adjusted to a predetermined additive element concentration by the same method as Example 1, Example 1 and A sample for analysis was cut out from the sintered body by the same method, and the density, additive element concentration, and average particle diameter were measured. A sputtering target was produced from this sintered body by the same method as in Example 1, and sputtering was performed under the same conditions as in Example 1, and the resistivity, arcing frequency, and etching rate were measured.

  Cd, Cr, Fe, Mn, Ni, Ca, Co, Cu, Mg, Pb, Ti, Zn, Si, and Al in the sputtering targets shown in Examples 1 to 6 and Comparative Examples 1 to 8 were added. Concentration, total concentration of Fe, Co, Si, Fe concentration, etching rate of sputtered thin films prepared using these sputtering targets, resistivity of these sputtered thin films, number of arcing during continuous discharge test, sputtering target Table 1 shows the average particle diameter and the relative density of each.

上記実施例１〜６及び比較例１〜８に示されるスパッタリングターゲット中のＣｄ、Ｃｒ、Ｆｅ、Ｍｎ、Ｎｉ、Ｃａ、Ｃｏ、Ｃｕ、Ｍｇ、Ｐｂ、Ｔｉ、Ｚｎ、Ｓｉ、Ａｌの合計した濃度とスパッタ薄膜のエッチングレートの関係を図１に示す。上記実施例１〜６及び比較例１〜８に示されるスパッタリングターゲット中のＦｅ、Ｃｏ、Ｓｉの合計した濃度とスパッタ薄膜のエッチングレートの関係を図２に示す。上記実施例１〜６及び比較例１〜８に示されるスパッタリングターゲット中のＦｅの濃度とスパッタ薄膜のエッチングレートの関係を図３に示す。上記実施例１〜６及び比較例１〜８に示されるスパッタリングターゲット中のＣｄ、Ｃｒ、Ｆｅ、Ｍｎ、Ｎｉ、Ｃａ、Ｃｏ、Ｃｕ、Ｍｇ、Ｐｂ、Ｔｉ、Ｚｎ、Ｓｉ、Ａｌの合計した濃度とスパッタ薄膜の抵抗率の関係を図４に示す。上記実施例１〜６及び比較例１〜８に示されるスパッタリングターゲットの平均粒径と２０時間のスパッタにおける積算アーキング数の関係を図５に示す。上記実施例１〜６及び比較例１、２に示されるスパッタリングターゲット中のＣｄ、Ｃｒ、Ｆｅ、Ｍｎ、Ｎｉ、Ｃａ、Ｃｏ、Ｃｕ、Ｍｇ、Ｐｂ、Ｔｉ、Ｚｎ、Ｓｉ、Ａｌの合計した濃度、Ｆｅ、Ｃｏ、Ｓｉの合計した濃度、及びＦｅの濃度とスパッタ薄膜のエッチングレートの相関係数を表２に示す。

The total concentration of Cd, Cr, Fe, Mn, Ni, Ca, Co, Cu, Mg, Pb, Ti, Zn, Si, and Al in the sputtering targets shown in Examples 1-6 and Comparative Examples 1-8. FIG. 1 shows the relationship between the etching rate and the etching rate of the sputtered thin film. FIG. 2 shows the relationship between the total concentration of Fe, Co, and Si in the sputtering targets shown in Examples 1 to 6 and Comparative Examples 1 to 8 and the etching rate of the sputtered thin film. FIG. 3 shows the relationship between the Fe concentration in the sputtering target shown in Examples 1 to 6 and Comparative Examples 1 to 8 and the etching rate of the sputtered thin film. The total concentration of Cd, Cr, Fe, Mn, Ni, Ca, Co, Cu, Mg, Pb, Ti, Zn, Si, and Al in the sputtering targets shown in Examples 1-6 and Comparative Examples 1-8. FIG. 4 shows the relationship between the resistivity and the sputtered thin film resistivity. FIG. 5 shows the relationship between the average particle diameter of the sputtering targets shown in Examples 1 to 6 and Comparative Examples 1 to 8 and the integrated arcing number in sputtering for 20 hours. The total concentration of Cd, Cr, Fe, Mn, Ni, Ca, Co, Cu, Mg, Pb, Ti, Zn, Si, and Al in the sputtering targets shown in Examples 1 to 6 and Comparative Examples 1 and 2 Table 2 shows the total concentration of Fe, Co, Si, and the correlation coefficient between the Fe concentration and the etching rate of the sputtered thin film.

表１より、実施例１〜６及び比較例１〜８のスパッタリングターゲットの密度は全て相対密度で９８％以上であることが示される。

Table 1 shows that the densities of the sputtering targets of Examples 1 to 6 and Comparative Examples 1 to 8 are all 98% or higher in relative density.

  From FIG. 1, when the total concentration of Cd, Cr, Fe, Mn, Ni, Ca, Co, Cu, Mg, Pb, Ti, Zn, Si, and Al in the sputtering target is lower than 50 ppm, the etching rate is 1.4 nm. Since the workability at the time of patterning is poor, the tact time becomes long, and there is a problem in practical productivity. If the concentration is higher than 1000 ppm, the etching rate is as fast as 2.2 nm / sec, which makes it difficult to control the etching time during patterning, which is a problem in practice. Further, as shown in FIG. 4, when the total concentration of Cd, Cr, Fe, Mn, Ni, Ca, Co, Cu, Mg, Pb, Ti, Zn, Si, and Al is higher than 1000 ppm, the resistivity is 18 μΩcm. It becomes a high value, and the required characteristics of Mo used as a low resistance material cannot be satisfied, which causes a problem.

  From FIG. 2, when the total concentration of Fe, Co, and Si in the sputtering target is lower than 20 ppm, the etching rate is lower than 1.4 nm / sec, and the tact time is long because of poor workability during patterning. Problems arise in productivity. When the concentration is higher than 200 ppm, the etching rate is as fast as 2.2 nm / sec, which makes it difficult to control the etching time during the patterning process, which is a problem in practice.

  As shown in FIG. 3, when the Fe concentration in the sputtering target is lower than 10 ppm, the etching rate is lower than 1.4 nm / sec, the workability during patterning is poor, and the tact time is increased, causing a problem in practical productivity. . If the concentration is higher than 150 ppm, the etching rate is as fast as 2.2 nm / sec, which makes it difficult to control the etching time during patterning, which is problematic in practice.

  As shown in FIG. 4, when the average particle size of the sputtering target is 13 μm or more, there is no arcing during sputtering, and there is no problem in practical productivity by sputtering. On the other hand, if it is smaller than 13 μm, arcing frequently occurs, which indicates that this is a problem in practical use.

  From Table 2, the correlation coefficient between the Fe concentration of the sputtering target and the etching rate is 0.871, the correlation coefficient of the total concentration of Fe, Co, and Si of the sputtering target and the etching rate is 0.929, The correlation coefficient between the total concentration of Cd, Cr, Fe, Mn, Ni, Ca, Co, Cu, Mg, Pb, Ti, Zn, Si, and Al and the etching rate is 0.982. This result shows that the etching rate can be controlled by controlling the Fe concentration in the sputtering target, but controlling the total concentration of Fe, Co, and Si can control the etching rate stably. It shows that controlling the total concentration of Cd, Cr, Fe, Mn, Ni, Ca, Co, Cu, Mg, Pb, Ti, Zn, Si, and Al can control the etching rate more stably. .

Total of elements of Cd, Cr, Fe, Mn, Ni, Ca, Co, Cu, Mg, Pb, Ti, Zn, Si, and Al in the sputtering targets obtained in Examples 1 to 6 and Comparative Examples 1 to 8 It is a figure which shows the relationship between a density | concentration and the etching rate of the thin film produced using the sputtering target. The figure which shows the relationship between the total density | concentration of the element of Fe, Co, and Si in the sputtering target obtained in Examples 1-6 and Comparative Examples 1-8, and the etching rate of the thin film produced using the sputtering target. is there. It is a figure which shows the relationship between the density | concentration of Fe in the sputtering target obtained in Examples 1-6 and Comparative Examples 1-8, and the etching rate of the thin film produced using the sputtering target. Total of elements of Cd, Cr, Fe, Mn, Ni, Ca, Co, Cu, Mg, Pb, Ti, Zn, Si, and Al in the sputtering targets obtained in Examples 1 to 6 and Comparative Examples 1 to 8 It is a figure which shows the relationship between a density | concentration and the resistivity of the thin film produced using the sputtering target. It is a figure which shows the relationship between the average particle diameter of the sputtering target obtained in Examples 1-6 and Comparative Examples 1-8, and the frequency | count of integration | stacking arcing when a continuous discharge test was done using the sputtering target.

Claims (2)

A sputtering target in which the main constituent element is Mo, and the total concentration of Cd, Cr, Fe, Mn, Ni, Ca, Co, Cu, Mg, Pb, Ti, Zn, Si, and Al is the sputtering target. The total concentration of Fe, Co, and Si is 20 ppm or more and 200 ppm or less, the concentration of Fe is 10 ppm or more and 150 ppm or less, and the average particle size is 13 μm or more and 200 μm or less, And a sputtering target characterized by having a relative density of 99% or more. A method for producing a thin film, wherein a film is formed by a sputtering apparatus using the sputtering target according to claim 1 .

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