JP2013032597A - Method for manufacturing sputtering target - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a sputtering target, with which the production cost of a large target or the like is reduced and further, production of particles due to the target is suppressed.SOLUTION: The method for manufacturing the sputtering target 1 includes a step of preparing a base body 2 and raw metal particles, and a step of forming a target layer 3 consisting of the deposit film of metal particles 4 on the base body 2 by spraying the raw metal particles on the base body 2 at high speed by applying the cold spray method. The raw metal particles are sprayed on the base body 2 so that a difference between P1 and P2 is within 10%, where P1 denotes the ratio of a first peak to a second peak in the X-ray diffraction chart of the target layer 3, and P2 denotes the ratio of a first peak to a second peak in the X-ray diffraction chart of the raw metal particles.

Description

  The present invention relates to a method for manufacturing a sputtering target.

  In semiconductor components and liquid crystal components, various wirings and electrodes are formed using a sputtering method. For example, various metal thin films and metal compound thin films are formed by a sputtering method on a deposition target substrate such as a semiconductor substrate or a glass substrate. These thin films are used as wiring layers, electrode layers, barrier layers, base layers (liner materials), and the like. When producing sputtering targets used for the formation of metal thin films and metal compound thin films, blocks such as melting and sintering are first subjected to processing such as forging and rolling, and heat treatment is used to remove processing strain and control the structure. Do. Thereafter, it is finished to a predetermined dimension by machining, and finally joined to a cooling backing plate.

  Sputtering targets tend to be upsized. In particular, sputtering targets used for forming liquid crystal components tend to increase the size of the target itself as the glass substrate increases. Since the sputtering target produced by applying the conventional melting method or sintering method is finished through various processes, an increase in manufacturing cost is inevitable as the target size increases. As the target size increases, the joining operation with the backing plate becomes difficult, so that the joining failure, the warping of the target, the peeling of the target during use, and the like are likely to occur. Furthermore, the product yield is likely to decrease due to an increase in the amount of generated particles and the induction of abnormal discharge.

  In order to solve this problem, it has been proposed to prepare a sputtering target by depositing raw material powder constituting the target while being melted on a substrate by a thermal spraying method (see Patent Documents 1 and 2). By applying a thermal spraying method to the formation of the target layer, the manufacturing cost of a large sputtering target can be reduced. However, regarding the target used in the sputtering apparatus, a manufacturing method using a thermal spraying method has not been put into practical use. The reason is that it is difficult to increase the density of the target layer (coating film) by the thermal spraying method. Furthermore, since the raw material powder is deposited while being melted in the atmosphere, an increase in the gas component in the target layer is also a problem. These cause a serious problem that abnormal discharge occurs frequently and the number of particles generated increases.

  A sputtering target used for forming a liquid crystal component is required to suppress an increase in splash caused by defects and an increase in particles due to the increase in target size. In semiconductor devices, in order to achieve a high degree of integration, the wiring width is being narrowed (for example, 0.13 μm, 0.09 μm, and further 0.065 μm or less). In a narrowed wiring or a semiconductor element having the wiring, even if a minute particle having a diameter of about 0.2 μm is mixed, wiring defects, element defects, and the like are caused. For this reason, it is desired to further suppress the generation of minute particles. The sputtering target to which the thermal spraying method is applied cannot meet such a requirement at all.

Japanese Patent Laid-Open No. 06-158303 JP 2002-339032 A

  The objective of this invention is providing the manufacturing method of the sputtering target which enabled it to suppress generation | occurrence | production of the particle resulting from a target, aiming at reduction of manufacturing cost, such as a large sized target.

  A method for producing a sputtering target according to an aspect of the present invention includes a step of preparing a base and metal raw material particles, a spray method applied to the base at a high speed to spray the metal raw particles, and a metal on the base A step of forming a target layer comprising a deposited film of particles, wherein the ratio of the first peak to the second peak in the X-ray diffraction chart of the target layer is P1, and the first in the X-ray diffraction chart of the metal source particles Spraying the metal raw material particles onto the substrate so that the difference between the P1 and the P2 is within 10% when the ratio of the peak to the second peak is P2, and the target layer In the cross section in the thickness direction, the maximum diameter of the metal particles is X, the minimum diameter is Y, the ratio of the maximum diameter X to the minimum diameter Y (X / Y) is the flatness of the metal particles, the target When the maximum diameter of the metal particles existing on the surface of the layer is X, the minimum diameter is Y, and the ratio of the maximum diameter X to the minimum diameter Y (X / Y) is the planar shape of the metal particles, the target The number ratio of the metal particles having a flatness ratio of 1.5 or more in a cross section in the thickness direction of the layer is 90% or more, and the planar shape of the metal particles present on the surface of the target layer is 1 or more and 2 A target layer having the following range is obtained by the step of spraying the metal raw material particles.

It is sectional drawing which shows the structure of the sputtering target by embodiment of this invention, and the cross-sectional state of a target layer. It is a top view which shows the surface state of the target layer shown in FIG. It is a figure for demonstrating the flatness of the metal particle in the cross section of a target layer. 6 is an enlarged photograph showing a cross-sectional observation result of an Al target layer according to Example 2. 6 is an enlarged photograph showing a cross-sectional observation result of an Al target layer according to Comparative Example 1.

  Hereinafter, modes for carrying out the present invention will be described. 1 and 2 are views showing a sputtering target according to an embodiment of the present invention. FIG. 1 is a diagram schematically illustrating a cross-sectional state of a target layer of a sputtering target, and FIG. 2 is a diagram schematically illustrating a planar state of the target layer. A sputtering target 1 shown in these drawings includes a base 2 and a target layer 3 formed thereon. The base 2 serves as an adherend of the target layer 3. For example, a metal base made of a metal selected from Cu, Al, and Fe or an alloy (SUS or the like) containing the metal as a main component is used.

  The metal substrate 2 may also serve as a cooling backing plate, or may be separate from the backing plate. When the metal substrate 2 separate from the backing plate is used, a step of joining the backing plate after forming the target layer 3 on the metal substrate 2 is required. In particular, with the large-sized sputtering target 1, it is difficult to join the backing plate, which may cause various defects. For this reason, it is preferable that the metal substrate 2 also serves as a backing plate.

  The target layer 3 has metal particles 4 deposited on the metal substrate 2. In other words, the target layer 3 is composed of a deposited film of metal particles 4. For the deposition of the metal particles 4 on the metal substrate 2, for example, a cold spray method is applied. In the cold spray method, metal raw material particles (raw material powder), which is a raw material of the metal particles 4, are put into a high-speed gas and collide with the metal substrate 2. An active surface appears on the surface of the metal substrate 2 by the collision energy of the metal raw material particles, and the metal raw material particles are plastically deformed by the collision energy. At that time, the collision energy is converted into thermal energy, and the metal substrate 2 and the metal raw material particles (metal particles 4) are joined.

  Due to the exothermic phenomenon at the time of collision, the metal particles 4 are mutually diffused and bonded to each other, so that a film in which the metal particles 4 are continuously deposited is obtained. Moreover, since the deposition rate and adhesion efficiency of the metal particles 4 are excellent, the coating has a thickness of several mm or more. Even when the coating is formed on the metal substrate 2 having a large area, the coating is peeled off or the metal substrate 2 is large. There is no warping. Furthermore, the relative density of the coating (target layer 3) thickened based on the deposition of the metal particles 4 is easy to increase compared to, for example, a coating deposited by the conventional thermal spraying method. A coating having a density of substantially 100% can also be obtained. The relative density of the coating tends to improve as the material of the metal raw material particles is easily plastically deformed (a material having a high plastic deformability) or a material having a lower softening temperature.

  In increasing the density of the target layer 3 made of the deposited film of the metal particles 4, it is important to use the high-speed collision energy of the particles. Therefore, it is desirable to accelerate the metal raw material particles beyond the critical speed at which the accelerated particles start to deposit. In order to accelerate the metal raw material particles to a critical velocity or higher, for example, an inert gas such as He gas having a small gas constant is used, and the metal raw material particles (raw material powder) are introduced into a gas flow having a flow velocity higher than the sonic velocity. The metal raw material particles thrown into the gas flow at or above the speed of sound are accelerated by the air flow and become above the critical velocity, and collide with the metal substrate 2 to form a coating continuously. When colliding with the metal substrate 2, the metal raw material particles are plastically deformed by the collision energy to become a flat shape, and the relative density of the coating is influenced by the flatness ratio.

  The high-density target layer 3 is realized by setting the number ratio of the metal particles (flat particles) 4 having a flatness ratio of 1.5 or more in the cross section in the thickness direction of the target layer 3 to 90% or more. Here, the aspect ratio is expressed by a ratio (X / Y) of the maximum diameter X to the minimum diameter Y, where X is the maximum diameter of the metal particles 4 in the cross section in the thickness direction of the target layer 3 and Y is the minimum diameter. The For example, as shown in FIG. 3, the flatness of the metal particles 4 is the maximum length X of the length (maximum length) of the particles appearing in the cross section in the thickness direction of the target layer 3 regardless of the flatness direction of the particles. Then, the length (minimum length) in the direction orthogonal thereto is measured as the minimum diameter Y.

The flatness of the metal particles and the abundance ratio of the flat particles are obtained by observing an arbitrary cross section in the thickness direction of the target layer 3 with an optical microscope, and measuring the shape (flatness) of the metal particles 4 in the field of view by image analysis. To ask for. The oblateness of each particle in the field of view is obtained by image analysis, and the number ratio of oblate particles (metal particles 4 with an oblateness of 1.5 or more) present per unit cross-sectional area (for example, 1 mm ² ) is obtained. Such measurement is performed on arbitrary cross-sections at 10 locations, and the average value thereof is defined as the abundance ratio (number ratio) of flat particles in the target layer 3.

  That the flatness of the metal particles (deposited particles) 4 deposited on the metal substrate 2 is less than 1.5 means that the energy when the raw material particles collide with the metal substrate 2 is insufficient. Therefore, when the ratio of the metal particles 4 having such an insufficient flat state increases, the target layer 3 made of the deposited film of the metal particles 4 cannot be sufficiently densified. In other words, it is possible to obtain a high-density target layer 3 by causing 90% or more of the metal particles (flat particles) 4 having a flatness ratio of 1.5 or more to be present in the cross section in the thickness direction of the target layer 3. .

  In the target layer 3 composed of the deposited film of the metal particles 4, the existence ratio (number ratio) in the cross section in the thickness direction of the metal particles (flat particles) 4 having a flatness ratio of 1.5 or more is preferably 90% or more. . Furthermore, the flatness of the metal particles 4 is preferably 2.0 or more. The target layer 3 has 90% or more of metal particles (flat particles) 4 with a flatness ratio of 1.5 or more in the cross section in the thickness direction, or metal particles (flat particles) 4 with a flatness ratio of 2.0 or more. It is preferable that 50% or more, 60% or more, or 90% or more be present in the cross section in the thickness direction. As a result, the relative density of the target layer 3 can be improved with higher reproducibility.

  In the cross section in the thickness direction of the target layer 3, the average flatness of the metal particles 4 is preferably 1.8 or more. By increasing the average flatness of the metal particles 4, the target layer 3 made of a deposited film of the metal particles 4 can be further densified. The average flatness of the metal particles 4 is a value obtained by averaging the flatness of all particles in the observation field of the optical microscope described above. Also in this case, measurement is performed on arbitrary 10 cross sections, and the average value thereof is defined as the average flatness. The average flatness of the metal particles 4 constituting the target layer 3 is desirably 2.0 or more.

  According to the deposited film that satisfies the flatness ratio of the metal particles 4 and the existence ratio of the flat particles, the target layer 3 having a relative density of 99% or more can be stably realized. If the relative density of the target layer 3 is less than 99%, for example, a splash phenomenon due to abnormal discharge is likely to occur, and this increases the amount of particles that cause defects in various sputtered films. This causes a decrease in the production yield of the sputtered film. The relative density of the target layer 3 is more preferably 99.5% or more. A deposited film having such a relative density can also be realized, and further, a deposited film having a relative density of substantially 100% can be realized.

  Further, as shown in FIG. 2, the target layer 3 represents the shape (planar shape) of the metal particles 4 existing on the surface by the ratio (X / Y) of the maximum diameter X to the minimum diameter Y of the metal particles 4. The average value is preferably in the range of 1 or more and 2 or less. Here, the planar shape of the metal particles 4 is obtained by observing the surface of the target layer 3 with an optical microscope and measuring the shape of the metal particles 4 in the field of view by image analysis, similarly to the cross-sectional shape. The X / Y ratio of each particle in the field of view is obtained by image analysis, and the average value is calculated. Such measurement is carried out for any 10 locations, and the average value thereof is taken as the average value of the planar shape of the metal particles 4 on the surface of the target layer 3.

  When the average value of the planar shape (X / Y ratio) of the metal particles 4 existing on the surface of the target layer 3 is in the range of 1 to 2, the target layer 3 can be formed when the sputtering target 1 is used for sputtering. Particles (sputtered particles) can be uniformly ejected from the surface of the surface. Thereby, the film thickness uniformity of the film deposited on the adherend substrate is improved. Furthermore, since the level difference between the metal particles 4 existing on the surface of the target layer 3 to be eroded becomes low, the amount of generated particles can be reduced. For this reason, it is desirable that the shape of the metal particles 4 existing on the surface of the target layer 3 be as equiaxed as possible.

  If the average value of the planar shape (X / Y ratio) of the metal particles 4 existing on the surface of the target layer 3 exceeds 2, the film thickness distribution of the sputtered film becomes non-uniform. Furthermore, since the erosion form is complicated, the particles are likely to fall off due to the steps between the metal particles 4, and thus the particles are easily induced. The average value of the planar shape (X / Y ratio) of the metal particles 4 is more preferably in the range of 1 to 1.5. Here, the shape of the metal particles 4 existing on the surface of the target layer 3 is defined. However, since the metal particles 4 are sequentially deposited on the metal substrate 2, they are cut in a direction parallel to the surface of the target layer 3. The cross section has a similar shape.

  In obtaining the target layer 3 having a structure in which the average value of the planar shape (X / Y ratio) of the metal particles 4 is in the range of 1 to 2, the metal material particles used as the material of the metal particles 4 are spherical or nearly spherical. It is preferable to use particles having a shape. When elliptical or flat metal raw material particles are used, the planar shape of the metal particles 4 tends to be irregular. Furthermore, the heating temperature and gas fluid pressure of the metal raw material particles are also important factors. The metal raw material particles are preferably heated near the softening temperature. These conditions are effective for controlling the flatness of the cross-sectional shape of the metal particles 4.

  In realizing the high-density target layer 3 with the deposited film of the metal particles 4, it is preferable to use a material that is easily plastically deformed or a material having a low softening temperature for the metal particles 4. Specifically, the metal particles 4 are preferably made of a metal selected from Al, Cu, Ti, Ni, Cr, Co, and Ta or an alloy containing the metal as a main component. More preferably, the metal particles 4 are made of Al, Al alloy, Cu, or Cu alloy. Even if the deposited film of metal material particles other than these can be increased in density by adjusting the deposition conditions and the like, the above-described metal particles 4 can be easily densified with high reproducibility. be able to. Therefore, this embodiment is suitable for the sputtering target 1 using the metal material described above as a sputtering material.

  According to the cold spray method, the metal raw material particles are deposited as the metal particles 4 without melting, so that the metal particles 4 are not oxidized during the deposition and the gas components such as oxygen and nitrogen do not increase. For this reason, the target layer 3 with low gas component content can be obtained by using metal raw material particles with low gas component amount. According to the sputtering target 1 having a high density and a low gas content, the number of particles generated by abnormal discharge can be suppressed. Therefore, it is possible to increase the yield of various thin films formed by a sputtering apparatus, as well as elements and components using the thin films. Furthermore, since the manufacturing cost of the sputtering target 1 can be reduced, the film forming cost can be reduced.

  Furthermore, since the metal raw material particles are deposited without melting, the metal particles 4 substantially maintain the crystal structure of the metal raw material particles. This makes it possible to improve the uniformity of the film thickness (sputtered film) obtained by sputtering the sputtering target 1. Specifically, the ratio of the first peak to the second peak in the intensity chart (X-ray diffraction chart) showing the X-ray diffraction result of the target layer 3 is P1, and the first peak in the X-ray diffraction chart of the metal raw material particles is When the ratio to the second peak is P2, the difference between P1 and P2 is set within 10%. The difference between P1 and P2 is a value determined based on the formula: [(P2-P1 (absolute value)) / P2 × 100 (%)]. Naturally, the first peak and the second peak of the target layer 3 and the metal raw material powder are based on the same crystal plane.

  If the difference in the peak ratio of the metal particles 4 constituting the target layer 3 to the raw material particles is within 10%, it is determined that the deposited metal particles 4 substantially maintain the crystal structure of the metal raw material particles. Can do. Then, by depositing the metal particles 4 while maintaining the crystal structure of the metal raw material particles, it is possible to suppress the film thickness variation of the sputtered film accompanying the change of the crystal structure. If the difference in the peak ratio exceeds 10%, the crystal structure of the metal particles 4 after deposition is different from the crystal structure of the metal raw material particles, and the film thickness of the sputtered film tends to be nonuniform. Thereby, the performance as the sputtering target 1 is lowered.

  The sputtering target 1 according to the above-described embodiment is manufactured as follows, for example. First, a metal powder (metal raw material particles) serving as a raw material for the metal particles 2 constituting the metal base 2 and the target layer 3 is prepared. In order to improve the density and deposition rate of the deposited film (target layer 3), the particle size of the metal powder is preferably adjusted as appropriate according to the material used. When a soft metal material such as Al or Cu is used, the average particle size of the metal powder is preferably in the range of 10 to 60 μm in consideration of the oxygen content and the like.

  The metal powder preferably has a spherical shape or a nearly spherical shape. When an elliptical or flat metal powder is used, the planar shape and cross-sectional shape of the metal particles 4 are likely to be irregular. A metal powder having a spherical shape or a shape close to a spherical shape can be obtained by an atomizing method, a rotating electrode method, a vacuum spray quenching method, or the like. These production methods are appropriately selected depending on the impurity content and the particle size of the metal raw material particles (metal powder as the raw material) to be used. Metal powder is put into a high-speed gas flow, and metal raw material particles accelerated by the gas flow are made to collide with the metal substrate 2. A target layer 3 made of a deposited film of metal particles 4 is formed on the metal substrate 2 based on the collision energy of the metal raw material particles.

The metal powder accelerates above the critical velocity at which particles begin to deposit in the gas stream. In order to accelerate the metal powder to a critical velocity or higher, an inert gas such as He gas having a small gas constant is preferably used for the gas flow into which the metal powder is charged. When He gas is used for the gas flow, it is preferable to recover He gas in the decompression chamber, increase the pressure, and reuse it in consideration of an increase in manufacturing cost due to consumption of He gas. When a film is formed in the decompression chamber, the particle velocity is improved, so that N ₂ gas or Ar gas can be used as the film forming gas. By using these inert gases, it is possible to realize a deposited film with a low oxygen content by preventing oxidation of the coating.

  It is preferable that the flow rate of the above-described inert gas is set to be equal to or higher than the sound velocity, and the metal powder is introduced into such a gas flow. In order to make the gas flow velocity equal to or higher than the sound velocity, the shape of the gas blowing nozzle is preferably made into a wrapper shape by narrowing the inner diameter. When gas is ejected from the constricted portion of the gas spray nozzle, the gas flow velocity becomes higher than the sonic velocity, and particles (metal powder) can be accelerated by the air flow to be higher than the critical velocity. In order to increase the deposition rate of particles and reduce the production cost of the target layer 3, it is effective to optimize the nozzle shape and to use a plurality of nozzles.

  When particles accelerated by the gas flow collide with the metal substrate 2, if the particle velocity is high, the surface oxide film is removed by plastic deformation of the particles, so that the oxygen content can be reduced. The critical speed at which deposition starts depends on the material of the metal particles, but when the particle speed is less than 700 m / sec, deformation at the time of particle collision is small and the removal of the surface oxide film is incomplete. This not only increases the oxygen content of the target layer 3, but also reduces the film density. On the other hand, when the particle velocity is 700 m / sec or more, the collision energy increases and the deformation of the particles increases, and the oxide film of the particles can be removed and the amount of oxygen in the deposited film can be reduced. As a result, the film density can be improved.

  The metal powder is preferably introduced into the gas stream while being heated to a temperature close to the softening temperature. This makes it easy to obtain a structure in which metal particles 4 having a surface shape (planar shape) that is equiaxed and a flat cross-sectional shape are deposited. The metal powder is preferably heated to the softening start temperature or higher. Furthermore, when He gas is used as the gas fluid, the gas pressure is preferably set to 0.6 MPa or more. As a result, the flow rate of the metal raw material particles is improved, so that it is easy to obtain a structure in which the metal particles 4 having a flat planar shape on the surface and a flat cross-sectional shape are deposited.

  By colliding the metal powder (metal raw material particles) accelerated by the gas flow as described above against the metal substrate 2, the target layer 3 made of a deposited film of the metal particles 4 is formed. The metal raw material particles are plastically deformed by the collision energy to the metal substrate 2 to make the cross-sectional shape flat, and the surface shape (planar shape) becomes equiaxed. Based on the shape of such metal particles 4, the target layer 3 having a high density and a low amount of gas components such as oxygen content can be obtained. Furthermore, since no grain growth occurs at the time of collision of the metal raw material particles, the target layer 3 composed of the fine metal particles 4 can be obtained. According to such a target layer 3, it is possible to suppress generation of particles during sputtering film formation.

  The target layer 3 formed by depositing metal raw material particles on the metal substrate 2 is preferably flattened by machining because the surface of the deposited film becomes uneven. There are fine deposits due to processing on the machined surface, which may be a source of particles at the initial stage of sputtering. For this reason, it is preferable to remove the deposit on the surface by subjecting the processed surface to a dry eye screening process or the like. Since dry ice itself does not contaminate the target surface, it is an effective means for cleaning the target surface. Dry ice may be directly sprayed with a few mm pellets, or may be sprayed in a state of being crushed to 1 mm or less. At this time, the gas pressure to be sprayed is preferably 0.3 MPa or more. If the pressure is lower than that, there is a possibility that the deposit cannot be removed sufficiently.

  When the target layer 3 formed by depositing metal raw material particles on the metal substrate 2 is used as it is, particles that easily fall off may adhere to the surface. For this reason, it is preferable to subject the deposited film of metal particles to a dry eye screening process or the like to remove particles that easily fall off the surface. If a prior surface treatment such as a dry eye screening treatment is not performed, particles tend to increase at the initial stage of sputtering. Since dry ice itself does not contaminate the deposited film, it is effective as a pretreatment for controlling the form of the deposited film.

  Furthermore, with regard to machining, since a large machining facility is required when the target size is increased, ball shot processing is also effective as a means for easily flattening unevenness on the surface of the deposited film. As a ball for flattening the surface, a zirconia ball having a ball diameter of 1.5 mm or more is effective, but the ball material is preferably the same material as the target layer 3 so as to reduce surface contamination. By using both the ball shot surface and the dry eye screening process, the deposits remaining on the smoothed processed surface are removed, and a surface free from foreign matter can be obtained. Therefore, it is possible to further reduce the generation amount of particles. The target layer 3 is subjected to annealing treatment as necessary for the purpose of softening or degassing the deposited film.

  Since the sputtering target 1 of this embodiment can form the deposited film of the metal particles 4 as the target layer 3 by a simple process of spraying particles, the manufacturing cost of the sputtering target 1 can be reduced. . In particular, since the target layer 3 having a large area can be formed satisfactorily and efficiently, the large sputtering target 1 can be manufactured at low cost. Furthermore, since the target layer 3 can be directly formed on the metal substrate 2 that also serves as a backing plate, there is no possibility of a bonding failure with the backing plate due to an increase in the size of the sputtering target.

  In addition, since the target layer 3 can be densified and the amount of gas components such as oxygen content can be reduced, abnormal discharge and occurrence of splash due to the abnormal discharge are suppressed. As a result, the amount of particles generated during sputtering can be reduced. Regarding the suppression of the particles, the fine particles of the target layer 3 and the planar shape also contribute. Since the target layer 3 substantially maintains the crystal structure of the metal raw material particles, the uniformity of the film thickness of the sputtered film can be improved. Therefore, by using the sputtering target 1 of this embodiment, it becomes possible to form a metal thin film or a metal compound thin film used as wiring of various elements and components, electrodes, barrier layers, base layers, etc. with a high yield.

  Furthermore, with respect to the used sputtering target 1, the target layer 3 can be regenerated by performing the deposition process of the metal raw material particles again on the eroded portion of the target layer 3. Thus, the target layer 3 of this embodiment can be recycled, and the manufacturing cost of the sputtering target 1 can be further reduced. Therefore, by applying such a sputtering target 1 to a sputtering apparatus for forming various thin films, it is possible to suppress mixing of particles into the sputtered film that causes a defect such as a wiring film or an element. It becomes possible to improve the productivity of elements, components, etc., and to reduce the film formation cost.

  Next, specific examples of the present invention and evaluation results thereof will be described.

(Examples 1-8)
First, a He gas flow of 100 psi (0.69 MPa) was generated in a cold spray apparatus provided with a Cu backing plate, and Al powder having an average particle diameter of 35 μm was added thereto. While the Al powder is heated to 200 ° C., an Al deposited film having a thickness of 12 mm is targeted by colliding on a Cu backing plate at a nozzle speed of 25 mm / sec, a pitch of 1 mm, and a powder supply rate of 20 to 40 g / min. Formed as a layer.

Next, each deposited film was machined to a size of 200 mm in diameter and 10 mm in thickness, and then the processed surface was subjected to dry eye screening treatment at a pressure of 0.45 MPa. Further, after performing the cleaning and drying treatment, the target Al sputtering target is heat-treated at 250 ° C. for 3 hours in a vacuum atmosphere of 3 × 10 ⁻² Pa or less as annealing treatment and degassing treatment. I got each. The relative density of the Al target layer of these sputtering targets, the amount of oxygen, the flatness of the Al particles, the abundance ratio of the flat particles, and the peak ratio by X-ray diffraction were measured and evaluated according to the method described above. The results are shown in Table 1. FIG. 4 shows the result of cross-sectional observation in the thickness direction of the Al target layer according to Example 2.

(Comparative Examples 1-4)
Except for setting the He gas pressure of the cold spray device to 50 to 80 psi (0.34 to 0.55 MPa), an Al powder similar to the above example was used, and an Al deposited film was formed as a target layer under the same conditions. . For these Al sputtering targets, the relative density, oxygen content, flatness of Al particles, etc. were measured and evaluated in the same manner as in the Examples. The results are shown in Table 1. A cross-sectional observation result in the thickness direction of the Al target according to Comparative Example 1 is shown in FIG.

(Comparative Example 5)
Using the same Al powder as in Example 1, an Al target layer was formed by low pressure plasma spraying. Specifically, after the vacuum chamber is evacuated, Ar gas is introduced to set the pressure in the chamber to 13 kPa, current 550 A, voltage 65 V, Ar gas flow rate / pressure is set to 75/80, Cu backing An Al deposited film having a thickness of 12 mm was formed as a target layer on the plate. Next, after the deposited film was machined to a size of 200 mm in diameter and 10 mm in thickness, the processed surface was subjected to dry eye screening treatment at a pressure of 0.45 MPa. Further, after washing and drying treatment, heat treatment was performed as annealing and degassing treatment at 250 ° C. for 3 hours in a vacuum atmosphere of 3 × 10 ⁻² Pa or less. Also for this Al sputtering target, the relative density, oxygen content, flatness of Al particles, etc. were measured and evaluated in the same manner as in the above examples. The results are shown in Table 1.

  The Al sputtering targets according to Examples 1 to 8 and Comparative Examples 1 to 5 described above were attached to a magnetron sputtering apparatus, and an Al thin film having a thickness of 0.3 μm was formed on the Si substrate. The number of particles having a diameter of 0.2 μm or more adhered on the Si substrate after film formation was measured with a particle counter. The number of occurrences of abnormal discharge in the sputtering process was detected with an arc monitor. These results are also shown in Table 1.

  As is clear from Table 1, when each sputtering target of Examples 1 to 8 was used, the amount of particles generated was smaller than that of Comparative Examples 1 to 4 and Comparative Example 5, and abnormal discharge was observed. It can be seen that the number of occurrences has also decreased. From these results, the sputtering targets of Examples 1 to 8 having Al target layers formed by depositing Al particles by a cold spray method with appropriate conditions effectively and stably suppress the generation of particles and abnormal discharge. It was confirmed that it was possible.

(Examples 9 to 15)
First, a He gas flow of 100 psi (0.69 MPa) was generated in a cold spray apparatus provided with a Cu backing plate, and Cu powder having an average particle diameter of 33 μm was added thereto. While the Cu powder is heated to 250 ° C., a Cu deposited film having a thickness of 12 mm is targeted by colliding on a Cu backing plate at a nozzle speed of 25 mm / sec, a pitch of 1 mm, and a powder supply amount of 20 to 40 g / min. Formed as a layer.

Next, each deposited film was machined to a size of 200 mm in diameter and 10 mm in thickness, and then the processed surface was subjected to dry eye screening treatment at a pressure of 0.45 MPa. Furthermore, after performing cleaning and drying treatment, heat treatment was performed under conditions of 250 ° C. × 3 hours in a vacuum atmosphere of 3 × 10 ⁻² Pa or less as annealing and degassing treatment, and the target Cu sputtering targets were respectively obtained. Obtained. The relative density, oxygen content, flatness of Cu particles, abundance ratio of flat particles, and peak ratio by X-ray diffraction were measured and evaluated according to the above-described methods. The results are shown in Table 2.

(Comparative Examples 6-9)
Except for setting the He gas pressure of the cold spray device to 50 to 80 psi (0.34 to 0.55 MPa), the same Cu powder as in the above example was used, and a Cu deposited film was formed as a target layer under the same conditions. . For these Cu sputtering targets, the relative density, oxygen content, flatness of Cu particles, etc. were measured and evaluated in the same manner as in the Examples. The results are shown in Table 2.

(Comparative Example 10)
Using the same Cu powder as in Example 9, a Cu target layer was formed by a low pressure plasma spraying method. Specifically, after the vacuum chamber is evacuated, Ar gas is introduced to set the pressure in the chamber to 13 kPa, current 600A, voltage 65V, Ar gas flow / pressure set to 75/80, and Cu backing. A 12 mm thick Cu deposited film was formed on the plate as a target layer. Next, after the deposited film was machined to a size of 200 mm in diameter and 10 mm in thickness, the processed surface was subjected to dry eye screening treatment at a pressure of 0.45 MPa. Further, after washing and drying treatment, heat treatment was performed as annealing and degassing treatment at 250 ° C. for 3 hours in a vacuum atmosphere of 3 × 10 ⁻² Pa or less. For this Cu sputtering target, the relative density, oxygen content, flatness of Cu particles, etc. were measured and evaluated in the same manner as in the above examples. The results are shown in Table 2.

  Each Cu sputtering target according to Examples 9 to 15 and Comparative Examples 6 to 10 described above was attached to a magnetron sputtering apparatus, and a Cu thin film having a thickness of 0.3 μm was formed on each Si substrate. The number of particles having a diameter of 0.2 μm or more adhered on the Si substrate after film formation was measured with a particle counter. The number of occurrences of abnormal discharge in the sputtering process was detected with an arc monitor. These results are also shown in Table 2.

  As is clear from Table 2, when each of the sputtering targets of Examples 9 to 15 was used, the amount of generated particles was small compared to the sputtering targets of Comparative Examples 6 to 9 and Comparative Example 10, and abnormal discharge occurred. It can be seen that the number of occurrences has also decreased. From these results, the sputtering targets of Examples 9 to 15 having Cu target layers formed by depositing Cu particles by the cold spray method with appropriate conditions effectively and stably suppress the generation of particles and abnormal discharge. It was confirmed that it was possible.

(Examples 16 to 23)
First, a He gas flow of 100 psi (0.69 MPa) was generated in a cold spray apparatus provided with a Cu backing plate, and Al powder having an average particle diameter of 27 μm was added thereto. As the Al powder, spherical particles produced by the rotating electrode method were used. While such Al powder is heated to 230 ° C., it collides onto a Cu backing plate at a nozzle speed of 30 mm / sec, a pitch of 1 mm, and a powder supply rate of 20 to 40 g / min, thereby depositing Al of 12 mm thickness. A film was formed as a target layer.

Next, each deposited film was machined to a size of 200 mm in diameter and 10 mm in thickness, and then the processed surface was subjected to dry eye screening treatment at a pressure of 0.45 MPa. Furthermore, after performing cleaning and drying treatments, heat treatment is performed in a vacuum atmosphere of 3 × 10 ⁻² Pa or less as an annealing and degassing treatment at 250 ° C. for 3 hours, and the target Al sputtering target is obtained. Obtained. The relative density of the Al target layer of these sputtering targets, the amount of oxygen, the flatness of Al particles in the cross section, the abundance ratio of the flat particles, and the shape (average value) of the Al particles on the surface were measured and evaluated according to the methods described above. The results are shown in Table 3.

  Each Al sputtering target according to Examples 16 to 23 was attached to a magnetron sputtering apparatus, and an Al thin film having a thickness of 0.3 μm was formed on each Si substrate. The number of particles having a diameter of 0.2 μm or more adhered on the Si substrate after film formation was measured with a particle counter. The number of occurrences of abnormal discharge in the sputtering process was detected with an arc monitor. These results are shown in Table 3. Table 3 also shows the results of Comparative Examples 1 to 4.

  As can be seen from Table 3, when the sputtering targets of Examples 16 to 23 were used, the generation amount of particles was small and the number of occurrences of abnormal discharge was also reduced. From these results, it was confirmed that the sputtering targets of Examples 16 to 23 can effectively and stably suppress the generation of particles and abnormal discharge.

(Examples 24 to 30)
First, a He gas flow of 100 psi (0.69 MPa) was generated in a cold spray apparatus provided with a Cu backing plate, and Cu powder having an average particle diameter of 28 μm was added thereto. As the Cu powder, spherical particles produced by the rotating electrode method were used. While such Cu powder is heated to 300 ° C., it is allowed to collide onto a Cu backing plate at a nozzle speed of 30 mm / sec, a pitch of 1 mm, and a powder supply rate of 20 to 40 g / min, thereby depositing Cu having a thickness of 12 mm. A film was formed as a target layer.

Next, each deposited film was machined to a size of 200 mm in diameter and 10 mm in thickness, and then the processed surface was subjected to dry eye screening treatment at a pressure of 0.45 MPa. Furthermore, after performing cleaning and drying treatment, heat treatment was performed under conditions of 250 ° C. × 3 hours in a vacuum atmosphere of 3 × 10 ⁻² Pa or less as annealing and degassing treatment, and the target Cu sputtering targets were respectively obtained. Obtained. The relative density of the Cu target layer of these sputtering targets, the amount of oxygen, the flatness of the Cu particles in the cross section, the abundance ratio of the flat particles, and the shape (average value) of the Cu particles on the surface were measured and evaluated according to the methods described above. The results are shown in Table 4.

  Each Cu sputtering target according to Examples 24 to 30 was attached to a magnetron sputtering apparatus, and a Cu thin film having a thickness of 0.3 μm was formed on each Si substrate. The number of particles having a diameter of 0.2 μm or more adhered on the Si substrate after film formation was measured with a particle counter. The number of occurrences of abnormal discharge in the sputtering process was detected with an arc monitor. These results are shown in Table 4. Table 4 also shows the results of Comparative Examples 6-9.

  As can be seen from Table 4, when each of the sputtering targets of Examples 24 to 30 is used, the generation amount of particles is small and the number of occurrences of abnormal discharge is also decreased. From these results, it was confirmed that the sputtering targets of Examples 24 to 30 can effectively and stably suppress the generation of particles and abnormal discharge.

  In the sputtering target manufacturing method according to the aspect of the present invention, a low-cost deposited film of metal particles is applied to the target layer, and the density of the deposited film (target layer) is increased. Therefore, it is possible to suppress the generation of particles due to the sputtering target while reducing the manufacturing cost of the sputtering target. According to the present invention, it is possible to provide a high-performance sputtering target at low cost.

  DESCRIPTION OF SYMBOLS 1 ... Sputtering target, 2 ... Base | substrate, 3 ... Target layer, 4 ... Metal particle.

Claims (8)

Preparing a substrate and metal raw material particles;
A step of spraying the metal raw material particles at a high speed by applying a cold spray method to the substrate to form a target layer made of a deposited film of metal particles on the substrate, the X-ray diffraction chart of the target layer When the ratio between the first peak and the second peak is P1, and the ratio between the first peak and the second peak in the X-ray diffraction chart of the metal raw material particles is P2, the difference between the P1 and the P2 is 10%. And the step of spraying the metal raw material particles to the substrate so as to be within,
The maximum diameter of the metal particles in the cross section in the thickness direction of the target layer is X, the minimum diameter is Y, the ratio of the maximum diameter X to the minimum diameter Y (X / Y) is the flatness of the metal particles, the target When the maximum diameter of the metal particles existing on the surface of the layer is X, the minimum diameter is Y, and the ratio of the maximum diameter X to the minimum diameter Y (X / Y) is the planar shape of the metal particles, the target layer The flatness of the metal particles present on the surface of the target layer is 1 or more and 2 or less, and the number ratio of the metal particles having a flatness ratio of 1.5 or more in the cross section in the thickness direction is 90% or more. The target layer which is the range of this is obtained by the spraying process of the said metal raw material particle, The manufacturing method of the sputtering target characterized by the above-mentioned. In the manufacturing method of the sputtering target of Claim 1,
A method of manufacturing a sputtering target, wherein the metal raw material particles are accelerated by an inert gas flow and collide with the substrate. In the manufacturing method of the sputtering target of Claim 2,
A method of manufacturing a sputtering target, wherein the metal raw material particles are accelerated by the inert gas flow while being heated. In the manufacturing method of the sputtering target of any one of Claims 1 thru | or 3,
An average flatness ratio of the metal particles in a cross section in the thickness direction of the target layer is set to 1.8 or more. In the manufacturing method of the sputtering target of any one of Claims 1 thru | or 4,
The method for producing a sputtering target, wherein the metal particles are made of a metal selected from Al, Cu, Ti, Ni, Cr, Co, and Ta or an alloy containing the metal as a main component. In the manufacturing method of the sputtering target of any one of Claims 1 thru | or 4,
The method for producing a sputtering target, wherein the metal particles are made of a metal selected from Al and Cu or an alloy containing the metal as a main component. In the manufacturing method of the sputtering target of any one of Claims 1 thru | or 6,
The method of manufacturing a sputtering target, wherein the substrate is made of a metal selected from Cu, Al, and Fe or an alloy containing the metal as a main component. In the manufacturing method of the sputtering target of any one of Claims 1 thru | or 7,
And planarizing the surface of the deposited film of metal particles;
And a step of subjecting the flattened surface to a dry eye screening process.

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