JPH08250426A - Manufacturing equipment for tungsten target for semiconductor - Google Patents

Abstract

PURPOSE: To provide a homogeneous thick plate having a large area with CVD method by uniformly supplying a raw material gas over a large area by providing a raw material gas supply section comprising a supply pipe and a subsequent conical, hollow, outlet hole having a perforated panel as a bottom surface. CONSTITUTION: A raw material gas supply pipe 3 is connected to a conical, hollow, outlet hole 5 having a perforated panel as the bottom. Size and intervals of the holes of the perforated panel 4 can be determined by considering passing velocity of the raw material gas and so forth. Also, it is possible to combine together a plurality of perforated panels having different hole positions, to make the diameter of holes in the central portion smaller than the diameters of holes in the peripheral portion or to provide a plurality of raw material gas supply pipes. It is desired to provide a cylindrical skirt 12 having almost the same size as that of a tungsten target aimed at. By providing this skirt 12, the flowing of a raw material gas in a lateral direction can be prevented, and then the raw material gas is able to definitely reach the substrate 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing a tungsten sputtering target used in semiconductor production.

[0002]

2. Description of the Related Art Generally, it is desirable that a semiconductor target has high purity and high density. If a target with a large size is manufactured by the powder metallurgy method, it is difficult to obtain a high density, and if a target with a low density is processed, a contaminant penetrates into the inside in the processing / cleaning process, and the target purity is lowered. Further, if the density is low, the discharge is very unstable when using sputtering, and abnormal discharge is likely to occur. When this abnormal discharge occurs, melting and explosion occur locally at the abnormal discharge generation part on the target surface, and particles are generated. If these particles adhere to the narrow wiring of the VLSI, malfunction of the semiconductor element and disconnection are likely to occur.

Therefore, in the case of a semiconductor target, it is desirable to use a target having a high purity and a high density with few particles generated during the use of sputtering. Examples of the method for producing such a target include electron beam melting-hot rolling method (Japanese Patent Laid-Open No. 61-107728) and H.
Pressure sintering by pressure sintering with P or HIP and rolling-
Hot rolling method (JP-A-3-150356, 5-2)
No. 22525) has been proposed.

[0004]

In the electron beam melting method, the crystal grains of the pure tungsten ingot are likely to be enlarged, and a large size plate is easily cracked during machining, resulting in extremely poor hot workability. Further, in the case of the sintering-hot rolling method, the pressurizing pressure is limited in the graphite type HP, and when the temperature exceeds 1,200 ° C., carbide formation occurs, so carbon as an impurity is mixed. When using a capsule, contamination of the material is a problem. In order to solve these problems, it is conceivable to apply a conventionally used film forming means by the CVD method and grow the film in the thickness direction to obtain a thick target material. However, this method is easy for obtaining a thin film, but has various problems in obtaining a thick material.

That is, peeling of the deposited tungsten from the substrate due to residual stress, generation of cracks, non-uniform thickness in a large area, or poor raw material yield due to difficulty in depositing only at desired locations, etc. .

[0006]

DISCLOSURE OF THE INVENTION As a result of intensive studies in view of such conventional problems, the present inventors have found that a method using a CVD reaction of tungsten hexafluoride and hydrogen has a very high purity in a specific apparatus. The present invention has been achieved by finding a precise target.

That is, according to the present invention, a raw material gas supply unit 6 consisting of a raw material gas conduit 3 and a raw conical raw material gas outlet 5 having a perforated plate 4 as a bottom, and an exhaust gas discharge unit 7, and a substrate are installed. Substrate 10 made of stainless steel on the base 9
A reaction container 2 including a raw material gas supply unit 6 located substantially in the center of the upper portion of the reaction container 2, and an exhaust gas discharge unit 7 provided on a side surface of the reaction container 2 and facing the exhaust gas discharge unit 7. The side surface of the reaction container 2 has a door 8 for loading and unloading the substrate mounting table 9, and the bottom of the reaction container 2 has a sliding part of the substrate mounting table 9.
The apparatus for manufacturing a tungsten target for a semiconductor is characterized by having a heating means 11 near the bottom. Also,
A mechanism in which the material outlet 5 rotates horizontally, or
This is an apparatus for manufacturing a tungsten target for a semiconductor in which a substrate rotating mechanism is provided on a substrate installation table 9.

FIG. 4 shows a conventional CV for forming a thin film.
1 illustrates an example of a D device 18 . The raw material gas is introduced into the reaction vessel 20 through the introduction part 19 and the heater 21
A substrate 23 is installed via a sample holder 22 (usually called a susceptor) installed above. This heater 2
The reaction product is deposited and deposited on the substrate 23 heated by 1. The apparatus of such a form has no particular problem in forming a thin film with a small area, but if the outlet of the source gas has a simple tube structure, the temperature of the central part of the substrate is lowered and the deposition is reduced. , Then cracks occur,
Peeling occurs. With such a configuration, it is extremely difficult to obtain a substantially uniform thickness when depositing in a thick plate shape, and a good large-area thickness due to partial peeling from the substrate due to uneven residual stress. A board cannot be made.

Conventionally, the CVD method has been used as a means for forming a thin film, and has not been recognized as a means for obtaining a thick film of about several millimeters.
The present inventors have focused on the CVD method as a means for satisfying the high purity, high density, and high reliability required for semiconductor targets.
In order to obtain by the method, it has been found that the uniform supply of the source gas over a wide area and the proper adhesion of the deposited tungsten with the substrate are indeterminate.

FIG. 1 shows an example of a tungsten target blank plate manufacturing apparatus 1 of the present invention. Reference numeral 3 denotes a raw material gas conduit, which is connected to a hollow conical raw material gas outlet 5 having a porous plate 4 as a bottom surface. FIG. 2 is a plan view showing an example of the arrangement of holes in the perforated plate 4. In this example, the holes 17 are arranged at regular intervals in a grid pattern, but they may be arranged in concentric circles or the like. The size and interval of the holes may be determined in consideration of the raw material gas passage speed and the like. It is also possible to combine a plurality of perforated plates having different positions of holes, to make the central part smaller than the hole diameter of the peripheral part, and to use a plurality of source gas conduits.

The porous plate 4 is preferably provided with a cylindrical skirt 12 having a size approximately the same as the size of the target tungsten target. By arranging the skirt 12, it is possible to prevent the raw material gas from flowing in the lateral direction and ensure that the raw material gas reaches the substrate 10.

In FIG. 1, 11 is a heating means, which can heat the substrate 10 through the bottom of the reaction vessel 2. The substrate 10 is set on a substrate setting table 9 slidably set on the bottom of the reaction container. The door 8 is opened when the substrate setting table 9 is taken in and out.

Stainless steel is the most preferable material for the substrate 10. With other materials, the adhesion between the substrate and the deposited tungsten is too good to allow the tungsten plate to be easily peeled off from the substrate after the reaction is completed, or the adhesion is too bad to cause partial cracking during the reaction, It cannot be peeled to obtain a plate having a desired size and shape.

Reference numeral 7 is an exhaust gas discharge part. With such a configuration, the raw material gas diffuses from the raw material gas introduction pipe 3 to the inner surface of the hollow cone of the raw material gas outlet 5 and reaches the perforated plate 4, and the raw material gas is uniformly blown out from each hole, Reactively deposited on the substrate 10.

Some unreacted gas and post-reaction gas are
It flows in all directions from above the substrate 10, and is finally discharged to the outside via the exhaust gas discharge unit 7. It is preferable that the substrate 10 is installed in the approximate center of the reaction container 2. This is because the flow of the source gas is formed substantially evenly in the vicinity of the substrate 10 to make the thickness of the deposited tungsten uniform, and from this aspect, the reaction vessel 2 is a plane much larger than the size of the substrate. It is preferable to have But,
It is not advisable to take a large space on the left and right and front and back because the device becomes large, and it is not wise in terms of price and installation location of the device, and the wall surface having the exhaust gas discharge part 7 is set to be long in other directions. Is advantageous because the same effect can be obtained by reducing the space with the substrate 10.

The shape and size of the hollow conical portion of the hollow conical raw material gas outlet 5 is restricted by the size of the perforated plate 4 to be used for its bottom portion, but its longitudinal length is You can change it freely. However, if the length is made too large, the apparatus becomes large, and if it is made too small, the gas discharged from the raw material gas conduit 3 is blown out from the porous plate 4 without being laterally diffused as it is, which is not preferable. Usually, as shown in FIG. 1, a cross-sectional shape with an apex angle of 90 to 120 degrees is suitable.

With such a structure, the source gas is blown onto the substrate 10 substantially evenly, and the thickness of the obtained tungsten plate is, as a matter of course, slightly thin in the peripheral portion of the substrate 10, but is generally uniform. It will be.

However, in order to obtain a tungsten target having a desired thickness, it is preferable to manufacture the target as thin as possible in consideration of the subsequent flattening cost in terms of raw material yield and flattening work amount.

For this purpose, it is preferable that the thickness of the obtained blank is uniform, but it is difficult to make the flow of the raw material gas strictly uniform in all directions. In this regard, it has been found that the raw material gas supply unit 6 or the substrate 10 can be rotated to make the thickness substantially uniform.

The structure for rotating the raw material gas supply unit 6 is basically the same as that shown in FIG. 1, and will be described with reference to FIG. The raw material gas conduit 3 and the raw material gas supply portion 6 below the freely attached portion are integrally rotated by a rotation mechanism (not shown) outside the reaction vessel 2.

On the other hand, FIG. 3 shows an example of a structure in which the substrate 10 is rotated. The basic structure is the same as that in FIG. 1, but a rotating shaft rotated by a rotating mechanism (not shown). A substrate 13 is rotatably fixed to the upper portion of the reaction container 2 at a position apart from the installation position of the substrate 10, and its tip is rotatably supported by the substrate installation table 9. The rotary shaft 13 can be easily removed from the substrate installation table 9, and the substrate 10 is taken out and put in when the substrate 10 is taken in and out. A gear 14 adapted to rotate on the substrate installation table 9 is attached to the rotary shaft 13,
The second gear 15 supported by the substrate mounting base 9 meshes with the gear 14 and meshes with the similar third gear 16. The third gear 16 has a peripheral edge protruding portion 25 in a shape that fits into the peripheral edge cutout portion 24 of the substrate 10. It is preferable that the protruding portion 26 of the substrate 10 be slightly longer than the protruding length of the peripheral edge protruding portion 25 of the gear 16. That is, the protruding portion 26 of the substrate 10 is placed in the concave portion of the gear 16 and rotates integrally with the gear 16, and the peripheral notch 24 of the substrate 10 and the peripheral protruding portion 25 of the gear 16 have a slight gap. To have. By doing this, for example, by placing a copper foil on this gap and on the upper part of the entire gear, and by the biting of the tooth part of the tungsten gear that is slightly deposited on the substrate due to the reaction, the rotation of the gear It is possible to avoid disturbing.

When the substrate is rotated via the plurality of gears in this way, the rotating mechanism itself includes the heating means 11
Since the structure is separated from the position, it is possible to avoid an adverse effect on the rotating mechanism due to heat, but it is also possible to directly rotate the substrate, for example, rotating from the bottom of the reaction container 2. It is possible to fix a rotary shaft that interlocks with the mechanism through the substrate setting table 9 and to provide a rotary table for mounting the entire substrate on the tip thereof, and rotate the rotary table as it is to rotate the substrate. . In this case, the mechanism itself is simple, but since the rotary shaft exists in an extremely short distance from the heating means, it is necessary to give sufficient consideration to the material and the like.

The method of rotating the raw material gas supply section and the method of rotating the substrate are simpler in terms of mechanism than the method of rotating the raw material gas supply section. However, even if this section is rotated, the apparatus itself is rotated. There may be some habit of the flow of the raw material gas depending on the characteristics of. In this respect, the substrate rotation method can eliminate this device characteristic. Rotation speed is 1-10r
A range of pm is preferable, and powder and particles are generated when rotating too fast.

[0024]

According to the present invention, since the source gas is blown out uniformly over the entire substrate, a large-area and thick tungsten target blank can be efficiently obtained with a uniform thickness.

[Brief description of drawings]

FIG. 1 shows a block diagram of an embodiment of a manufacturing apparatus of the present invention.

FIG. 2 is a plan view showing an example of arrangement of holes in a perforated plate in FIG.

FIG. 3 shows a block diagram of another embodiment of the present invention.

FIG. 4 shows a configuration diagram of a conventional general CVD apparatus.

[Explanation of Codes] 1 . Reactor 2. Reaction vessel 3. Raw material gas pipe 4. Perforated plate 5. Raw material gas outlet 6. Raw material gas supply unit 7. Exhaust gas exhaust unit 8. Door 9. Substrate installation stand 10. Substrate 11. Heating means 12. Skirt 13. Rotating shaft 14. Gear 15. Gear 16. Gear 18 CVD device 19. Introduction section 20. Reaction vessel 21. Heater 22. Sample holder 23. Substrate 24. Peripheral notch 25. Peripheral protrusion 26. Protrusion

Claims (3)

[Claims] 1. A raw material gas conduit 3 followed by a perforated plate 4
A reaction gas container 2 including a raw material gas supply unit 6 having a hollow conical raw material gas outlet 5 having a bottom surface, an exhaust gas discharge unit 7, and a substrate 10 made of stainless steel on a substrate installation table 9, The raw material gas supply unit 6 is located substantially in the center of the upper portion of the reaction container 2, and the exhaust gas discharge unit 7 is provided on the side surface of the reaction container 2. 8. A manufacturing apparatus of a tungsten target for a semiconductor, comprising: a reaction chamber 2; and a slide part of a substrate mounting table 9 at the bottom of the reaction vessel 2, and a heating means 11 near the bottom of the reaction vessel 2. 2. The apparatus for manufacturing a tungsten target for semiconductor according to claim 1, wherein the raw material outlet 5 has a mechanism for rotating in the horizontal direction. 3. The apparatus for manufacturing a tungsten target for semiconductor according to claim 1, wherein the substrate setting table 9 has a substrate rotating mechanism.