JP4172019B2 - Target material manufacturing method - Google Patents

Description

  The present invention relates to a method for producing a target material by hot isostatic pressing.

  A target material used for forming an electric wiring film, an electrode, and the like of a liquid crystal display (hereinafter referred to as LCD) for manufacturing a thin film device is required to be increased in size as the LCD substrate is increased in size. In the case of forming a thin film on such a large substrate, the target material manufactured in the size of 2 or 3 divisions has been used so far to achieve the required sputtering area. However, since a foreign matter is generated from the joint at the time of sputtering and becomes defective, an integral target material is required.

  When producing such a large-sized target material by the pressure sintering method of powder, it is important to achieve high density and cope with large size. The pressure sintering method mainly includes a hot press method that performs two-dimensional pressurization and a hot isostatic press (hereinafter referred to as HIP) method that can apply press pressure in three dimensions. However, since the isotropic pressure can be applied to the sintered material, the HIP method is excellent in uniformly densifying the sintered material.

Regarding the production of large target materials by the HIP method, vibration and press pressure were filled when filling in order to eliminate the filling unevenness that occurs when filling powder with the increase in the size of metal capsules for HIP. It is proposed to give to powder (for example, refer patent document 1).
JP 2000-366638 A

The technique described in Patent Document 1 uses a metal capsule having a wide opening area and a shallow depth, but the metal capsule is enlarged due to a demand for an increase in the size of the target (an increase in area). As a result of widening, there is a problem in that the probability of occurrence of defects in the welded portion increases due to an increase in the welding distance during sealing.
In addition, when the raw material powder is not uniformly deposited when the powder is filled into the metal capsule, the HIP process may cause deformation or the like. However, in Patent Document 1, vibration and press pressure are applied to the filled raw material powder. However, there is a problem that it is difficult to deposit uniformly as the area to be deposited becomes larger.

  An object of the present invention is to provide a method for producing a target material that is less likely to cause uneven filling and can easily improve the sintered density.

  The present invention provides a metal capsule having a substantially rectangular parallelepiped shape in which one surface facing in the direction in which the filling depth is deepest is released as a filling port, and a long side length of 1000 mm or more. After placing so that the filling port is on the upper side, the raw material powder is filled from the filling port, and then the filled raw material powder is pressed with an upper lid having a deaeration hole, and then sealed under reduced pressure. This is a method for producing a target material, which is subjected to hot isostatic pressing with the capsule filling port facing upward, to obtain a sintered body.

Moreover, this invention is a manufacturing method of the said target material as described above filled with giving vibration to the said raw material powder.
Moreover, this invention is a manufacturing method of the said target material as described in the above which cut | disconnects the sintered compact which gave the hot isostatic pressing to multiple in the orthogonal | vertical direction with respect to a filling port surface.
Moreover, this invention is a manufacturing method of the target material as described above which makes raw material powder the metal powder which mainly has Mo whose average primary particle diameter is 10 micrometers or less.

  According to the present invention, in the method of manufacturing a large sintered target material by the HIP method, when filling the raw material powder into the metal capsule, it is uniformly filled without generating filling unevenness, so that after the HIP sintering Since deformation can be prevented, it is effective for producing a sintered target material having a large area.

One of the important features of the present invention is to make the filling uniform by the dead weight of the raw material powder by using one surface facing the direction where the filling depth is deepest as a filling port. When a raw material powder is filled into a metal capsule having a substantially rectangular parallelepiped shape to which the present invention is applied and its long side is 1000 mm or more, the depth is 1000 mm or more, and the effect on the uniformity of filling of the raw material powder by its own weight is obtained. Become clear.
Furthermore, the present invention is also characterized in that a high packing density is realized by sealing an upper lid having deaeration holes while pressed against the raw material powder. That is, by pressing with the upper lid, it is possible to eliminate the space from the upper layer part where the action of its own weight does not work, and it becomes a uniform and dense filling state from the upper layer part to the lower layer part, and the occurrence of deformation or the like due to HIP can be prevented. Note that pressing with the upper lid can eliminate almost no gap between the upper lid and the powder, and can prevent the occurrence of a dent due to the presence of the gap. In particular, in an expensive large target to which the present invention is applied, the occurrence of a defective portion due to the deformation of the edge or the presence of a dent is directly connected to the fact that the target shape for a predetermined sputter area cannot be secured. Prevention of deformation and the like by the method is extremely important.

In the present invention, it is necessary to perform hot isostatic pressing with the filling port of the metal capsule facing upward. This is because, after sealing, it is ideal to complete the HIP process as it is filled in order to eliminate powder bias and movement.
The procedure of the production method of the present invention will be described with reference to the schematic diagrams of the metal capsule shown in FIGS. In the present invention, as shown in FIG. 1, the metal capsule 1 for performing hot isostatic pressing has a substantially rectangular parallelepiped shape, and the filling port 2 is opened with the long side Z as the filling depth direction. After the metal capsule 1 is placed so that the filling port 2 is opened with the filling port 2 open, the raw material powder 3 is filled as shown in FIG. Then, as shown in FIG. 3, after the filling of the raw material powder 3 is completed, the upper lid 4 having the deaeration holes 5 is sealed with the raw material powder 3 pressed against the filling port 2 of the metal capsule 1, and the upper lid 4 is welded. Next, pressure is reduced from the deaeration holes to further seal the deaeration holes. Thereafter, as shown in FIG. 4, a sintered body is obtained by HIP in a state where the filling port 2 in which the metal capsule 1 is sealed with the upper lid 4 is turned upward. By obtaining a sintered target material by the above method, it is possible to obtain a target material with high density and reduced warpage.

  In addition, it is desirable to reduce the gap between the raw material powders by applying an external stress to the metal capsule during the filling of the raw material powders, and to improve the packing density of the raw material powders. As this external stress, methods such as vibration, tapping or direct pressing of the raw material powder can be used. Among them, vibration is more preferable because the supply of the raw material powder and the application of external stress can be performed continuously.

Currently, a target material having a larger area of the sputtering surface is demanded as the LCD becomes larger. In the present invention, since one side facing the direction in which the filling depth is deepest is used as the filling port, the cut surface is sintered by cutting the sintered body subjected to HIP in a direction perpendicular to the filling port surface. Since it can be set to the maximum area of a bonded body, it is preferable when obtaining the target material which makes a sputtering surface a large area.
In the target material, the thickness in the direction perpendicular to the sputtering surface varies depending on the sputtering apparatus, but in most cases is 20 mm or less. Therefore, after designing the shape of the sintered body using the maximum area of the sintered body after HIP as the sputtering surface of the target material, the sintered body is cut into a predetermined plate thickness perpendicular to the filling port surface and the target. Producing a material is preferable from the viewpoint of production efficiency because a large number of target materials can be produced by a single HIP process.

As the raw material powder of the present invention, a refractory metal having an average primary particle size of 10 μm or less is more effective. Among refractory metals, especially raw material powders such as Mo and W are generally produced by a hydrogen reduction method, and therefore are inevitably fine for manufacturing reasons and have a tendency to agglomerate with an increase in specific surface area. This is because it is difficult to increase the packing density when filling the metal capsule.
Further, the primary particle size is not the aggregated apparent size but the particle size of each powder. In this invention, when this average primary particle diameter is 10 micrometers or less, since it becomes easy to aggregate, it is suitable for this invention.

  In the present invention, the dimensions of the metal capsule vary depending on the type of sputtering apparatus used and the inner diameter of the HIP apparatus, but regarding the dimensions of the filling port surface, the thickness (X in FIG. 1) is 50 to 800 mm and the width (FIG. Y in 1 is preferably 50 mm or more. This is because by cutting the sintered body in a direction perpendicular to the filling port surface, a large number of targets having a thickness of 20 mm or less can be produced by one HIP, thereby enabling efficient production at low cost. . Further, as the thickness of the filling port surface is increased, the filling area is increased and it is difficult to deposit the powder uniformly. Further, the width dimension of the filling port surface depends on the thickness dimension of the target, but is required to be a dimension equal to or greater than the thickness, so that it is preferably 50 mm or greater.

  In addition, when filling the raw material powder into the metal capsule in the present invention, it is also possible to reinforce and fill the side surface of the metal capsule with a side plate in order to prevent deformation of the metal capsule.

Examples of the present invention will be described below.
While applying vibration to a metal capsule made of mild steel having a size of 135 × 605 × 2300 (mm) and a filling port size of 135 × 605 (mm), Mo having an average primary particle diameter of 6 μm was filled from the filling port. After the filling of the raw material powder is completed, the upper lid having a deaeration hole is fitted into the filling port of the metal capsule by impact with a hammer so that the raw material powder is pressed and sealed, and the upper lid is welded. The deaeration hole was deaerated under reduced pressure and sealed. Thereafter, HIP treatment was performed with the filling port of the metal capsule facing upward, and the metal capsule was removed by machining to obtain a sintered body, which was further machined to obtain a target material having a predetermined shape. Hereinafter, it is referred to as Invention Example 1.
As Comparative Example 1, after the metal capsule was filled with Mo having an average primary particle diameter of 6 μm in the same manner as described above, the upper lid having deaeration holes was sealed in accordance with the filling port of the metal capsule, and the upper lid was welded. Then, the deaeration hole was deaerated under reduced pressure and sealed. Then, the HIP process was performed similarly to the above, and the target material was produced.

The packing density of the raw material powder of Invention Example 1 and Comparative Example 1 into the metal capsule was measured, and a sample of 10 × 10 (mm) was taken from the location shown in FIG. Are shown in Table 1. Here, the packing density is a numerical value represented by (filling weight of raw material powder) / (volume weight) × 100, and the relative density is represented by (density of target material) / (theoretical density) × 100. It is a numerical value.
Table 1 shows the results of the deformation amount of the sintered body after the HIP treatment. As shown in the schematic diagram of FIG. 7, the warp amount of the metal capsule is a deformation amount 11 calculated from the difference between the reference point 9 on the bottom surface of the central portion 8 in the longitudinal direction of the sintered body 7 and the bottom surface of the end portion 10. That is.

  As shown in Table 1, as in Example 1 of the present invention, a raw material powder is applied to a metal capsule whose one side facing the direction in which the filling depth is deepest is a filling port and whose long side is 1000 mm or more. According to the method of sealing and sealing the raw material powder in a state where the raw material powder is pressed by applying external stress to the upper part of the metallic capsule and fitting it into the metallic capsule, the filling of the raw material powder is improved and the relative amount of the target material is increased. The density is high and a uniform level can be realized, and there is no deformation of the sintered body after HIP. Further, in Comparative Example 1, since the material powder is not hermetically sealed in a state of pressing the raw material powder by applying external stress to the metal capsule and fitting it into the metal capsule, due to the gap generated by the upper lid and the raw material powder, Since there may be a dent as shown in FIG. 6 on the end face of the sintered body on the filling port side after HIP, there is a problem in producing a large target material.

  The Mo sintered body produced in the same manner as Example 1 of the present invention was cut perpendicularly to the filling port surface with a vertical saw and machined to produce six target materials. Samples of 10 × 10 (mm) were taken from each of the six target materials shown in FIG. 5, and the relative density was measured in the same manner as in Example 1. Since the relative density of each sample is 99.3 to 99.4% and is in a uniform density state, according to the manufacturing method of the present invention, a large number of samples having the same relative density by one HIP treatment. Target material can be produced.

It is a schematic diagram which shows an example of the metal capsule of this invention. It is a schematic diagram which shows an example which filled the raw material powder in the metal capsule of this invention. It is a schematic diagram which shows an example of the state which sealed the upper cover of the metal capsule of this invention. It is a schematic diagram which shows an example of the state which hot-isostatic-pressed the metal capsule of this invention. It is a schematic diagram which shows the position which extract | collected the sample of Mo target material produced in the Example. 6 is a schematic diagram showing an end face of a Mo sintered body of Comparative Example 1. FIG. It is a schematic diagram which shows the measuring method of the curvature amount of the sintered compact in an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal capsule, 2 Filling hole, 3 Raw material powder, 4 Top cover, 5 Deaeration port, 6 Welding part, 7 Sintered body, 8 Center part, 9 Reference point, 10 End surface, 11 Warpage amount, 12 Depression, 13 Target material

Claims (4)

One surface facing in the direction where the filling depth is deepest is a substantially rectangular parallelepiped shape released as a filling port, and the filling port has a metal capsule having a long side length of 1000 mm or more. After placing so as to be on the upper side, the raw material powder is filled from the filling port, and then the raw material powder filled with the upper lid having a deaeration hole is sealed under reduced pressure, and then the filling port of the metal capsule A method for producing a target material, characterized in that a hot isostatic pressing is performed in a state in which is placed above to obtain a sintered body. The method for producing a target material according to claim 1, wherein the raw material powder is filled while applying vibration. 3. The method for producing a target material according to claim 1, wherein the sintered body subjected to hot isostatic pressing is cut into a plurality of pieces in a direction perpendicular to the filling port surface. 4. Wherein the raw material powder, method for producing a target material according to any one of claims 1 to 3, wherein the average primary particle diameter of the metal powder consisting mainly of less Mo 10 [mu] m.

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