JP3825191B2 - Aluminum alloy sputtering target material - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  TECHNICAL FIELD The present invention relates to an aluminum (hereinafter sometimes referred to as “Al”) alloy sputtering target material, and more particularly, an electrode suitable for forming an electrode film for a liquid crystal display, particularly an active matrix liquid crystal display having a thin film transistor. The present invention relates to an Al alloy sputtering target material for film formation.
[0002]
[Prior art]
  Liquid crystal displays (hereinafter referred to as “LCDs”) are thinner, lighter, and consume less power than conventional CRTs, and can produce high-resolution images. is there. Recently, in order to further improve the image quality, an LCD having a structure in which a thin film transistor (hereinafter referred to as “TFT”) is incorporated in the LCD as a switching element has been proposed and widely used. Here, the TFT refers to an active element formed by connecting an electrode made of a thin film metal to a semiconductor thin film formed on an insulating substrate such as glass. In this specification, an electrode includes an electrode itself used as a part of a TFT and a wiring on a thin film.
[0003]
  There are various characteristics required for the electrodes used in the LCD, but low specific resistance is the most important characteristic in order to prevent signal delay which is an obstacle to the increase in size and definition of LCDs, which has recently been demanded. It is becoming.
[0004]
  The LCD electrode is formed by first forming a uniform thin film having a thickness of about submicron by sputtering, and then forming a fine electrode pattern by lithography or the like. In such a sputtering method, a sputtering target is appropriately selected according to the target electrode composition. This sputtering target is a raw material for forming an electrode thin film by sputtering, and is usually a disk-shaped or flat plate. In sputtering, the sputtering target is used as a negative electrode, the substrate on which a thin film is to be formed is used as a positive electrode, and both are arranged facing each other in a vacuum chamber into which a sputtering gas such as Ar is introduced. A direct current voltage is applied between the two electrodes to cause glow discharge. The sputtering gas is ionized by this discharge, and the ion particles are accelerated by the electric charge and irradiated onto the sputtering surface of the target. By exchanging kinetic energy when the ion particles collide with the sputtering surface, atoms constituting the sputtering target are released into the space and deposited on a substrate disposed opposite to the sputtering surface to form a uniform thin film. It is formed.
[0005]
  As sputtering target materials for forming electrodes for such LCDs, refractory metals such as Ta, Ti, Cr, and Mo have been used so far. However, along with the recent increase in size and definition of LCDs, the wiring width of electrode circuits is being miniaturized to 10 microns or less, and the wiring film thickness is also being miniaturized to several thousand mm or less. On the other hand, conventionally used refractory metals such as Ta, Ti, Cr, and Mo are not suitable for electrode materials for large and high-definition LCDs because of their large electrical resistivity in the thin film state. Therefore, it has been desired to develop an electrode material for LCD having a low electrical resistivity in place of the refractory metal.
[0006]
  Examples of the electrode material for LCD with low electrical resistivity include Au, Cu, and Al. However, Au has poor etching characteristics for patterning into a predetermined shape after the formation of the sheet-like electrode film, and is expensive. Further, Cu has problems in film adhesion and corrosion resistance, and neither is suitable for practical use.
[0007]
  On the other hand, Al does not cause the above-mentioned problems, can form good ohmic contacts with Si, has a high selectivity with respect to photoresist, and can be easily microfabricated, and can form semiconductor devices (ie, elements on a Si wafer). In addition, it has an advantage that it has abundant use results as an electrode material of an integrated circuit of a semiconductor device), and also has an advantage that a low-priced and high-purity material is available.
[0008]
  However, when an electrode for LCD is formed on a substrate by sputtering using a sputtering target material made of Al or an Al alloy, particles scattered from the target are clustered and directly attached to a thin film on the substrate, or a sputtering apparatus. The particle phenomenon that adheres to and deposits on the walls and parts inside the film formation chamber and then peels off and adheres to the thin film on the substrate, and the splash phenomenon that the droplets of the sputtering target material scatters and adheres to the thin film on the substrate occurs. There is a problem. Above all, the occurrence of splash is a serious problem because it causes a serious hindrance to the performance of the thin film on the substrate and the electrode formed thereon. Such splash is generated not only in the case of forming electrodes for LCD as described above, but also by forming an integrated circuit of a semiconductor device, a reflective layer of a magneto-optical recording medium, etc. by sputtering using an Al or Al alloy sputtering target material. In some cases, this is a problem, and it is hoped that it will be resolved.
[0009]
  For example, Japanese Patent Application Laid-Open No. 8-13141 proposes a sputtering target in which the amount of oxide remaining in a target material made of an aluminum alloy is 3 ppm or less to deal with the problem of the generation of particles and splash during sputtering. In Japanese Patent Laid-Open No. 9-25564, the amount of inclusions having an average particle diameter of 10 microns or more appearing on the sputtering surface of the target is 40 / cm.² An aluminum alloy sputtering target is proposed in which the oxygen content in the target is less than 15 ppm.
[0010]
[Problems to be solved by the invention]
  However, the above measures for reducing the amount of inclusions contained in the sputtering target material as much as possible have not been sufficient to suppress particles and splash.
[0011]
  The present invention has been made in view of such a situation, and an object thereof is to provide an Al alloy sputtering target material that does not generate splash during sputtering.
[0012]
  Another object of the present invention is to provide an Al alloy sputtering target material for forming an electrode film having a low electrical resistivity suitable for an electrode of a liquid crystal display.
[0013]
  A further object of the present invention is to provide an Al alloy sputtering target material in which the composition does not change over time during sputtering and the in-plane composition variation of the deposited electrode thin film is suppressed.
[0014]
[Means for Solving the Problems]
  According to the present invention,An aluminum alloy sputtering target material manufactured by a spray forming method,In an aluminum alloy sputtering material comprising an aluminum matrix phase and an intermetallic compound phase of aluminum and an alloy element, a crystal grain boundary between the aluminum matrix phases, a boundary between the intermetallic compound phases, and an aluminum matrix phase and the intermetallic compound There is no oxide layer having a layer thickness of 0.1 microns or more at the phase boundary, the average crystal grain size of the aluminum matrix phase is 5 microns or less, and the average crystal grain size of the intermetallic compound phase is 3 microns. An aluminum alloy sputtering target material is provided which is characterized by:
[0015]
  Here, the alloy element is at least one element selected from the group consisting of Y, Nd, Ta, Ti, Zr, Cr, Mn, W, Mo, Fe, Co, Ni, Cu, Ag, Si, and Ge. This is good.
[0016]
  Also, 100,000 intermetallic compound phases having a particle size of 0.01 micron or more are contained in the aluminum matrix phase.² It is desirable to distribute with the above density.
[0017]
  Further, the oxygen content in the sputtering target material is preferably 1,000 ppm or less, and the nitrogen content is preferably 500 ppm or less.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
  The present invention was made based on the results of investigations made by the inventors of the present invention on the production of Al alloy sputtering target materials having various components and structures, and the sputtering conditions of these sputtering target materials. One is that there is no oxide layer having a layer thickness of 0.1 microns or more at the grain boundary of the aluminum matrix phase, the boundary between the intermetallic compound phases, and the boundary between the aluminum matrix phase and the intermetallic compound phase. It is in.
[0019]
  That is, the present inventors have found that a molten layer is formed at a location where cooling is hindered during sputtering on the surface of the Al alloy sputtering target, and that the splash occurs as a result of being ejected as droplets by electromagnetic force. As a result, the factor that inhibits this cooling is mainly an inclusion (non-metallic inclusion such as an oxide or an intermetallic compound) layer present in the sputtering target, among which an oxide layer having a low thermal conductivity is present. They found that cooling was hindered and that the thickness of the oxide layer had a great influence on cooling hindrance.
[0020]
  The layer thickness of the oxide layer in the present invention is 7 of the cross section of the Al alloy sputtering target by transmission electron microscope (TEM).,The value measured from a 500 times magnified photograph.
[0021]
  Here, the grain boundary of the aluminum matrix phase, the boundary between the intermetallic compound phases, the boundary between the aluminum matrix phase and the intermetallic compound phase are:FIG.Each part shown in the TEM photograph of the Al alloy sputtering target material structure.
[0022]
  Another major feature of the present invention is that the average crystal grain size of the aluminum matrix phase is 5 microns or less, more preferably 3 microns or less. That is, generally, even if the constituent elements and composition of the crystal are the same, the sputtering yield varies depending on the crystal orientation. For this reason, in the aluminum matrix phase, which is a polycrystal, the orientation of each crystal grain in the matrix phase is random, so the erosion rate during sputtering differs between the crystal grains, and a step occurs between the crystal grains. To do. Such steps between crystal grains are more likely to occur as the crystal grain size is larger.
[0023]
  By the way, in sputtering using Al or an Al alloy, a direct current magnetron sputtering method is generally widely used. In the sputtering method, a magnet is disposed on the back surface of the sputtering target material, and a leakage magnetic field is generated on the surface of the sputtering target, thereby concentrating plasma on the surface of the sputtering target (increasing the plasma density in the vicinity of the target surface) and sputtering efficiency. It is a thing that raised. In particular, in order to improve the use efficiency of the sputtering target material, an improved method is generally used in which the magnetic force distribution is constantly changed by moving or swinging the magnet during sputtering. In such an improved method, if sputtering is captured instantaneously, plasma concentrates only on the surface of the sputtering target material having a magnet on the back surface, and local erosion proceeds. At this time, atoms constituting the sputtering target material are released into the space from the local area of the target material surface, and may be deposited on the opposing substrate, or may adhere to the surrounding sputtering target material surface. When the magnet on the back surface of the sputtering target material moves and reaches the back surface of the attached portion, the attached material is sputtered again. At this time, the deposit is not thermally bonded to the sputtering target material and is not sufficiently cooled, so that it becomes droplets by heating and becomes splash.
[0024]
  Such adhesion is likely to occur when the crystal grain size is large due to the steps between the crystal grains, and as a result, splash is likely to occur when the crystal grain size is large. Therefore, the relationship between the crystal grain size of Al alloy and the occurrence of splash was investigated in detail.FIG.Is a graph in which the horizontal axis represents the average crystal grain size of the Al matrix phase and the vertical axis represents the number of splashes of 10 microns or more. From this figure, when the average crystal grain size is 5 microns or less, the number of splashes is less than two. It is difficult to see that no splash occurs at 3 microns or less.
[0025]
  Another major feature of the present invention is that the average crystal grain size of the intermetallic compound phase is 3 microns or less, more preferably 2 microns or less.FIG.From the results of the study by the present inventors, it was found that the average crystal grain size and the splash number are in a proportional relationship.FIG.Is a diagram in which the horizontal axis is the average crystal grain size of the intermetallic compound and the vertical axis is the number of splashes of 10 microns or more, and as the average crystal grain size increases, the splash number increases. It can be seen that no splash occurs when the diameter is 3 microns or less.
[0026]
  In order to control the average crystal grain size of the intermetallic compound phase to a desired grain size of 3 microns or less, an Al alloy billet is prepared by melting / forging methods (including spray forming method, atmospheric melting method, vacuum melting method). Control the cooling rate during forgingAs shown in Example 2 described later, the rolling reduction performed after obtaining the ingot is changed.Just do it.
[0027]
  Although there is no restriction | limiting in particular as an alloy element used by this invention, In order to achieve further reduction in electrical resistance of the Al electrode film formed on the board | substrate, Y, Nd, Ta, Ti, Zr, Cr, Mn, W, It is preferably at least one element selected from the group consisting of Mo, Fe, Co, Ni, Cu, Ag, Si, and Ge. The content of the element is preferably in the range of 0.1 to 5.0 at%.
[0028]
  The intermetallic compound phase is 100,000 particles / mm in which the particle size is 0.01 microns or more in the aluminum matrix phase.² It is desirable to distribute with the above density. 100,000 intermetallic compound phases / mm² If the density is lower than the density, the composition of the sputtering target material itself becomes non-uniform, and as a result, the composition of the thin film formed on the substrate or the like becomes non-uniform and may adversely affect the performance of the LCD.
[0029]
  Furthermore, the oxygen content in the sputtering target material is desirably 1,000 ppm or less, and more preferably 500 ppm or less. When the oxygen concentration is high, a large amount of the oxygen precipitates in the Al matrix phase as a granular oxide (alumina) in the sputtering target material, and the possibility of splash due to the precipitate increases. In addition, an Al alloy electrode film formed on a substrate using a sputtering target material having a high oxygen content concentration has a high electrical resistivity due to the oxygen content, and may reduce the corrosion resistance of the electrode film.
[0030]
  On the other hand, the nitrogen content in the sputtering target material is desirably 500 ppm or less, and more preferably 250 ppm or less. The reason why the nitrogen content is preferably 500 ppm or less is that an increase in electrical resistivity of the Al alloy thin film formed using the sputtering target material can be suppressed. For example, when producing an Al alloy sputtering target material by the spray forming method, if nitrogen gas is used as the atomizing gas in the gas atomizing process, the nitrogen content in the obtained Al alloy sputtering target material is increased, and this sputtering target material is used. The Al alloy thin film formed by sputtering has a high concentration of nitrogen. For this reason, there exists a possibility that the electrical resistivity of the said thin film may become high.
[0031]
  The sputtering target material of the present invention is a spray forming method in terms of reducing the nitrogen content, preventing the formation of an oxide layer, and miniaturizing the Al matrix phase and the intermetallic compound phase.Manufactured using. Here, the spray forming method means that a composition of a sputtering target material is melted, atomized using nitrogen gas, buretted in a semi-molten state, and then formed into a desired form by forging, hot pressing, HIP, or the like. That means.
[0032]
【Example】
  Hereinafter, the contents of the present invention will be described in detail using examples.
[0033]
  In the following examples:The observation measurement of the occurrence of splash is the ultimate vacuum: 1 × 10^-6Torr, discharge power 10W / cm² Then, after DC magnetron sputtering was performed for 1 hour under the condition of the distance between the electrodes of 40 mm to form an Al2.0 at% Nd alloy thin film on the substrate, the number of splashes having a diameter of 10 microns or more present on the surface of the thin film was measured with an optical microscope It was performed by the method of measuring using. The substrate used was a 4 inch diameter glass substrate, and the substrate temperature was room temperature. The reason why the splash with a diameter of 10 microns or more is used as the measurement target is that the splash with a diameter of 10 microns or more causes a serious problem in thin film performance and becomes a problem.
[0034]
  Example1
  Spray forming method,An Al 2.0 at% Nd alloy was melted by powder metallurgy to produce an ingot.In the spray forming method, the molten alloy was gas atomized and deposited in a mold to obtain an Al 2.0 at% Nd alloy ingot. At this time, nitrogen gas was used as an atomizing gas in the gas atomizing step in the spray forming method.In the powder metallurgy method, 100-mesh pure Al powder and pure Nd powder were mixed by a V-type mixer and then sintered at 550 ° C. by the HIP method to produce an Al 2.0 at% Nd alloy ingot.
[0035]
  The ingot produced by the spray forming method or the powder metallurgy method was forged and rolled and then machined to obtain an Al 2.0 at% Nd alloy sputtering target material having a 4 inch diameter.
[0042]
  The alloy structures of the various Al 2.0 at% Nd alloy sputtering target materials thus prepared were observed. Further, sputtering was performed under the conditions shown in Table 1, and the degree of occurrence of splash at that time was observed and measured. For observation of the alloy structure, a microscopic sample was taken from the sputtering target material, a part of the sample was cut using a microtome, processed to a thickness of 1000 angstroms by electropolishing and ion milling, and then subjected to a transmission electron microscope (TEM). ). A part of the sample was polished, and the texture was observed by SEM. Table 2 shows the investigation results of the alloy structure and the degree of occurrence of splash.
[0036]
[Table 1]
[0037]
[Table 2]
[0038]
  Splash generation was not observed in the sputtering target material produced by the spray forming method. Here, a TEM photograph of the sputtering target material structure produced by the spray forming method is shown.7Shown in Figure7Therefore, the presence of the Al matrix phase 1 and the intermetallic compound phase 2 is recognized, but the presence of the oxide layer is not recognized throughout the alloy structure. Next, SEM photograph of sputtering target material structure produced by powder metallurgy method8Shown in Figure8Then, the state in which the intermetallic compound phase 2 having a crystal grain size of 5 to 30 microns is dispersed in the Al matrix phase 1 is observed. The Al matrix phase 1 is composed of a sintered body of pure Al powder particles, and the powder particles have a polycrystalline structure with an average crystal grain size of 10.2 microns. Figure9Is an enlarged TEM photograph of one pure Al powder particle. Al single crystal grains 3 are observed in the Al powder particles, and the presence of an intermetallic compound phase is not observed, but the oxide layer 4 is surrounded around the powder particles. It can be seen that is formed.
[0039]
  As shown in Table 2, there is a difference in the number of splashes generated between the sputtering target material prepared by the spray forming method and that prepared by the powder metallurgy method. That is, the number of splash occurrences is zero for the former material, whereas it is 4/100 cm for the latter material.² It has occurred. This difference is considered to be due to the presence of an oxide layer having a layer thickness of 0.3 microns in the latter material.
[0040]
  Example2
  A plurality of ingots were prepared by melting an Al 2.0 at% Ta alloy by two types of melting methods, a vacuum melting method and a spray forming method. In the vacuum melting method, the alloy was melted in a vacuum, and when cast into a mold, the molten metal was passed through an alumina filter to remove oxide (alumina) contained in the molten metal. The ingot was rolled at 300 ° C. after forging, and the pressure ratio was changed in the range of 10 to 90% to produce billets in which the particle size of the intermetallic compound (Ta) in the alloy was changed variously. . The billet was machined to obtain a 4 inch diameter Al2.0 at% Ta alloy sputtering target material. The surface of this Al 2.0 at% Ta alloy sputtering target material is mirror-finished by buffing, etched with a 5% NaOH aqueous solution for 1 minute, and observed for microfabrication with an optical microscope, and the metal present in the sputtering target. Intermetallic compound (Al_Three The average grain size of Ta) was measured. At this time, there was no oxide layer in the sputtering target material, and the average crystal grain size of the Al matrix phase was 5.4 microns by the vacuum melting method and 1.7 microns by the spray forming method. Further, in the same manner as in Example 1, the number of splashes generated during sputtering was investigated. Based on the results of this investigation, the relationship between the average crystal grain size of the intermetallic compound phase and the number of splashes of 10 microns or more was determined. Figure the result1Shown in Figure1Therefore, when the average particle size of the intermetallic compound phase increases, the number of splashes increases, and when the average crystal particle size of the intermetallic compound phase decreases, the number of splashes decreases. In particular, when the average crystal grain size of the intermetallic compound phase is 3 microns or less, the number of splashes becomes zero, and it can be seen that the occurrence of splash can be completely suppressed.
[0041]
  Example3
  A plurality of ingots were prepared by melting an Al 2.0 at% Ta alloy by two types of melting methods, a vacuum melting method and a spray forming method. In the vacuum melting method, the alloy was melted in a vacuum, and when cast into a mold, the molten metal was passed through an alumina filter to remove oxide (alumina) contained in the molten metal. The ingot is rolled at 300 ° C. and a reduction rate of 50% after forging, and then held at a different temperature in the range of room temperature to 600 ° C. for 3 hours to recrystallize the alloy structure of the ingot to obtain an average Al matrix phase. Billets with various crystal grain sizes were prepared. The billet was machined to obtain an Al 2.0 at% Ta alloy sprack ring target material having a diameter of 4 inches. At this time, no oxide layer was present in the sputtering target material, and the average crystal grain size of the intermetallic compound phase was 15.9 microns by the vacuum melting method and 2.5 microns by the spray forming method. The average crystal grain size of the Al matrix phase of this Al 2.0 at% Ta alloy sputtering target material and the number of occurrences of splash during sputtering2Measured and observed in the same manner. Based on this measurement result, the relationship between the average crystal grain size of the intermetallic compound phase and the number of splash occurrences of 10 microns or more was determined. Figure the result2Shown in Figure2Therefore, when the average crystal grain size of the Al matrix phase increases, the number of splashes increases, and when the average crystal grain size of the Al matrix phase decreases, the number of splashes decreases, and in particular, the average grain size of the Al matrix phase is 3 microns or less. In this case, the number of splashes becomes zero, and it can be seen that the occurrence of splash can be completely suppressed.
[0042]
  Example4
  Three examples of melting method, vacuum melting method, spray forming method, and powder metallurgy method.2In the same manner, an Al 2.0 at% Nd alloy ingot was produced. After the ingot was forged and rolled, an Al 2.0 at% Nd alloy sputtering target material having a 4 inch diameter was obtained by machining. When the alloy structure of the target material was examined in the same manner as in Example 1, no oxide layer was present in the sputtering target material, and the average crystal grain size of the Al matrix phase was 5.4 microns by the vacuum melting method. 1.2 micron by spray forming method, 10.2 micron by powder metallurgy method, average crystal grain size of intermetallic phase is 8.4 micron by vacuum melting method, 2.5 micron by spray forming method, powder metallurgy 2.0 microns. Further, the number per unit area of intermetallic compound phases of 0.01 μm or more present in the Al matrix phase was measured. The results are shown in Table 3.
[0043]
[Table 3]
[0044]
  In the sputtering target material by the vacuum melting method and the spray forming method, the number of intermetallic compound phases per unit area was 91,827 and 128,767, both exceeding 10,000, but by the powder metallurgy method In the sputtering target material, the number was 198, which was much smaller than the previous two manufacturing methods.
[0045]
  Next, sputtering film formation was performed under the sputtering conditions shown in Table 4, and the change with time of the thin film composition was examined. Here, the change in the composition of the thin film over time was as follows: 3,000 mm of thin film was formed every 10 hours with continuous discharge (the time required for film formation was about 120 seconds), and the electrical resistivity of the film formation sample was searched for 4 times. Measured by the needle method, the spattering time and the composition variation of the film formation sample (thin film sample) were examined.
[0046]
[Table 4]
[0047]
  Fig. 3 shows the measurement results of changes in electrical resistivity over time for thin film deposited using the sputtering target material.3Shown in The electrical resistivity of the thin film sample formed with each sputtering target material changes with the lapse of time of sputtering, and in the target 1 by the vacuum melting method, the electrical resistivity tends to gradually increase with the lapse of time of sputtering. Is recognized. This increase in electrical resistivity is due to compositional variation of the Al 2.0 at% Nd alloy thin film, specifically due to an increase in Nd content. On the other hand, in the target 2 by the spray forming method, the electrical resistivity was almost constant regardless of the elapsed time of sputtering. Moreover, in the target 3 by the powder metallurgy method, the electrical resistivity varied randomly with the lapse of time of sputtering. This variation in electrical resistivity means that the composition variation of the target material is large. Further investigation was conducted on this point. Figure4Is a plan view of a glass substrate having a diameter of 50 mm, and the electrical resistance of the thin film formed on the glass substrate is measured at measurement positions 1 to 5 in the figure, and the electrical properties of the thin film sample formed using each sputtering target material The in-plane variation in resistivity was measured. The results are shown in Table 5. Here, the electrical resistivity was measured on a thin film sample formed after 10 hours from the start of sputtering.
[0048]
[Table 5]
[0049]
  In the target 2 by the spray forming method, there is almost no difference in the sheet resistance between the measurement positions. In the target 1 by the vacuum melting method, the sheet resistance of 0.05Ω is at most, whereas in the target 3 by the powder metallurgy method, the measurement is performed. A maximum sheet resistance difference of 0.08Ω (about 20%) was observed between the positions.
[0050]
  Example5
  An Al3.0 at% Ti alloy ingot was produced in the same manner as in Example 1 by three types of melting methods: vacuum melting, spray forming, and powder metallurgy. The ingot was forged and rolled, and then machined to obtain an Al3.0 at% Ti alloy sputtering target material having a 4 inch diameter. When the oxygen content in the alloy of these sputtering target materials was analyzed, the oxygen content of the sputtering target material produced by the respective melting methods of the vacuum melting method, the spray forming method and the powder metallurgy method was 120 ppm, 420 ppm and 1130 ppm, respectively. And the oxygen content of the sputtering target material produced by the powder metallurgy method was a remarkably high value. Here, the analysis of the oxygen content was performed by collecting a sample for gas analysis from the sputtering target material and analyzing the sample.
[0051]
  Examples4Sputtering was performed in the same manner as described above, and the electrical resistivity was measured for the formed thin film sample by changing the sputtering discharge power density. Figure5Is a graph in which the vertical axis represents the thin film electrical resistivity and the horizontal axis represents the sputtering discharge power density. From this figure, the sputtering target material produced by the vacuum melting method and the spray forming method differs in the thin film electrical resistivity. Although not recognized, the sputtering target material produced by the powder metallurgy method showed a remarkably high value for the thin film electrical resistivity. Note that the tendency of the thin film electrical resistivity to decrease when the sputtering discharge power density is increased is irrelevant to the present invention.
[0052]
  Example6
  Example5A thin film having a thickness of 400 mm was formed on a transparent polycarbonate resin substrate having a thickness of 1.27 mm under the sputtering conditions shown in Table 4 using the sputtering target material prepared in 1. On the thin film, an acrylic resin was applied by spin coating so as to have a thickness of 10 microns, and a protective film was formed as a sample. With respect to this sample, the reflectance with a laser beam having a wavelength of 780 nm was measured from the transparent polycarbonate resin substrate side. As a result, the reflectivity of the sputtering target material by the vacuum melting method, the spray forming method, and the powder metallurgy method was 86.9%, 87.2%, and 87.3%, respectively. Next, the sample was subjected to PCT (Pressure Cooker Test: temperature 105 ° C., pressure 1.2 atm, humidity 100% RH) as an environmental acceleration test to evaluate the corrosion resistance of the sample thin film. As a result, the reflectivity after 100 hours of PCT is 85.0%, 85.1%, and 71.0%, respectively. When a sputtering target material by powder metallurgy is used, the reflectivity of the thin film is significantly reduced. It was found that the corrosion resistance was inferior.
[0053]
  The decrease in reflectance occurs when the surface roughness of the thin film increases due to corrosion of the thin film, or the thin film is oxidized to become a transmission film. In this case, the reflectivity decreases due to increased irregular reflection of the laser beam on the surface of the thin film and transmission of the laser beam.
[0054]
  Example7
  In the same manner as in Example 1, an Al 2.0 at% Nd alloy, an Al 0.3 at% Ti alloy, and an Al 2.0 at% Ta alloy ingot were obtained by three types of melting methods: vacuum melting, spray forming, and powder metallurgy. Produced. The ingot was forged and rolled and then machined to form a sputtering target material having a 4 inch diameter. The nitrogen content of these sputtering target materials was analyzed. Further, sputtering film formation was performed under the sputtering conditions shown in Table 4, and the electrical resistivity of the formed thin film sample was measured. Here, the analysis of the nitrogen content was performed by collecting a sample for gas analysis from the sputtering target material and analyzing the gas of this sample. The electrical resistivity was measured by a four-probe method.
[0055]
  Figure shows the relationship between the nitrogen content of the sputtering target material and the electrical resistivity of the formed thin film sample.6Shown in Figure6Thus, a good correlation is recognized between the nitrogen content in the sputtering target material and the electrical resistivity of the thin film sample, and the thin film electrical resistivity increases as the nitrogen content increases. Although the influence of the nitrogen content on the increase (rate) of the thin film electrical resistivity varies depending on the type of Al alloy, since nitrogen as an impurity increases the electrical resistivity in particular, the content is 500 ppm or less, preferably 250 ppm or less. It can be seen that it is better to keep it down.
[0056]
【The invention's effect】
  According to the Al alloy sputtering target material according to the present invention, splash is unlikely to occur during sputtering, and an electrode film suitable for an electrode of a liquid crystal display (wiring on the thin film and the electrode itself) can be formed. In addition, an electrode film suitable for an electrode (wiring on the thin film and the electrode itself) of the liquid crystal display can be formed in terms of low electrical resistivity. Furthermore, there is little change in the composition over time during sputtering, and variations in the composition of the formed electrode thin film can be suppressed.
[Brief description of the drawings]
[Figure1】Example2It is a figure which shows the relationship between the average particle diameter of the intermetallic compound about the sputtering target material concerning, and the splash number of 10 microns or more.
[Figure2】Example3It is a figure which shows the relationship between the average crystal grain diameter of Al matrix phase about the sputtering target material concerning, and the splash number of 10 microns or more.
[Figure3】Example4It is a figure which shows the relationship between sputtering elapsed time and thin film electrical resistivity about the sputtering target material concerning.
[Figure4】Example4It is a figure which shows the thin film electrical resistivity measurement position about the sputtering target material concerning.
[Figure5】Example5It is a figure which shows the relationship between the sputtering discharge power density and thin film electrical resistivity about the sputtering target material from which oxygen content which concerns on differs.
[Figure6】Example7It is a figure which shows the relationship between nitrogen content about the sputtering target material concerning, and a thin film electrical resistivity.
[Figure7A TEM photograph (magnification: × 7,500) of a sputtering target material structure produced by a spray forming method.
[Figure8It is a SEM photograph (magnification: x100) of a sputtering target material structure produced by powder metallurgy.
[Figure9It is an enlarged TEM photograph (magnification: × 7,500) of pure Al powder particles of a sputtering target material produced by a powder metallurgy method.
[Explanation of symbols]
1 Al matrix phase
2 Intermetallic phase
3 Al single crystal grain
4 Oxide layer

Claims (5)

An aluminum alloy sputtering target material produced by a spray forming method, comprising an aluminum matrix phase and an intermetallic compound phase of aluminum and an alloy element. There is no oxide layer with a layer thickness of 0.1 microns or more at the boundary between the intermetallic phases and at the boundary between the aluminum matrix phase and the intermetallic phase, and the average crystal grain size of the aluminum matrix phase is 5 microns or less. An aluminum alloy sputtering target material, wherein an average crystal grain size of the intermetallic compound phase is 3 microns or less.   The alloy element is at least one element selected from the group consisting of Y, Nd, Ta, Ti, Zr, Cr, Mn, W, Mo, Fe, Co, Ni, Cu, Ag, Si, and Ge. The aluminum alloy sputtering target material according to claim 1. 3. The aluminum alloy sputtering according to claim 1, wherein the intermetallic compound phase having a particle size of 0.01 microns or more is distributed in the aluminum matrix phase at a density of 100,000 / mm ² or more. Target material.   4. The aluminum alloy sputtering target material according to claim 1, wherein the oxygen content is 1,000 ppm or less.   The aluminum alloy sputtering target material according to any one of claims 1 to 4, wherein the nitrogen content is 500 ppm or less.