KR100848818B1 - Cvd diamond synthesis apparatus for uniform coating onto particles - Google Patents

Abstract

The present invention relates to a CVD diamond synthesis apparatus capable of depositing a uniform diamond film on the surface of a particulate base material. To this end, in the present invention, a mechanism for tilting a vacuum chamber for CVD diamond synthesis is provided, and a mechanism for rotating a substrate support for fixing a substrate on which base material particles are placed in the vacuum container is provided. Accordingly, by inclining the vacuum vessel at a predetermined angle during diamond synthesis and rotating the substrate support, the substrate particles are moved, thereby enabling uniform diamond deposition on the substrate particles having a diameter of 50 µm to 5 mm.

CVD, Diamond Synthesizer, Tilting, Rotating

Description

CCVD Diamond Synthesizer with Uniform Coating on Particle Base Material {CVD DIAMOND SYNTHESIS APPARATUS FOR UNIFORM COATING ONTO PARTICLES}

Figure 1 schematically shows an example of a CVD diamond synthesis apparatus having a tiltable vacuum vessel according to the present invention, (A) the central axis (L) of the container for diamond synthesis is constant with the vertical axis (M) of the synthesis apparatus (B) shows the cross section viewed from the right angle direction of (a).

Figure 2 is a schematic diagram showing the base material particles placed on the substrate, (a) is a state for the diamond synthesis vessel or the substrate support is horizontal, (b) the center axis (L) of the vessel is a vertical axis ( The state which maintained constant angle from M) is shown.

FIG. 3 is a schematic view of a deformed substrate manufactured to alleviate the tendency of the base material particles shown in FIG. 2 (b), wherein (a) is a plan view and (b) is a cross-sectional view taken along the dotted line shown in (a). Indicates.

FIG. 4 illustrates the movement of the base material particles according to the tilting of the container on the modified substrate shown in FIG. 3, wherein (a) the center axis L of the container is perpendicular to the horizontal plane (reference plane, bottom plane). In the case, (b) and (c) indicate the case where the central axis L of the container is inclined at a predetermined angle with the horizontal plane.

Explanation of symbols on the main parts of the drawings

1: container for diamond synthesis 2: tower portion

3: supporting part 4: auxiliary equipment

5: Connector 5-1: Fixing groove

6: fixed wedge 8: plasma

9: base material particle 10: substrate

11: Substrate Support 11-1: Hanging Jaw

12: rotating mechanism (motor) 13: deformation substrate

13-1: Home

L: central axis of the container for diamond synthesis

M: vertical axis of CVD diamond synthesis apparatus

TECHNICAL FIELD The present invention relates to a CVD diamond synthesis apparatus, and more particularly, to a CVD diamond synthesis apparatus that allows the substrate particles to move during diamond synthesis, thereby enabling uniform diamond coating on the substrate particles.

Since the first CVD diamond synthesis was known in the 1980s, several types of synthesis equipment have been developed. Diamond synthesizing apparatus is classified according to the method of activating the raw material gas. To date, the apparatus used for commercial diamond synthesizing includes hot-filament CVD, direct current plasma enhanced CVD, and microwave plasma. (microwave plasma enhanced CVD) and DC arc jet CVD.

According to the CVD diamond synthesis method, a raw material gas (mainly methane) activated by heat or plasma in a vacuum vessel is nucleated and grown in the form of particles on a base material to grow into a polycrystalline film. Usually, a diamond film deposited to a thickness of several nm to several hundred micrometers on a base material (substrate) on a plate is used while attached to a substrate (direct coating: a thin film of several tens of micrometers or less) or a free standing separated from the substrate. It is used in the form (thick film of several hundred micrometers or more). As such, CVD diamond is generally obtained on a fixed plate-like base material.

On the other hand, diamond shell manufacturing technology has recently been developed (Korean Patent Application No. 2004-0083710, Korean Patent Application No. 2005-0030824). In order to manufacture such a diamond shell, the process of depositing a uniform diamond film on the particle | grain (mainly spherical) base material of several micrometers-5 mm in diameter is required.

The method of moving the particulate base material is to vibrate the substrate on which the particles are placed (Japanese Patent Laid-Open No. 2-080396, Japanese Patent Laid-Open No. 1-270596, Japanese Patent Laid-Open No. 59-137311), or a gas is introduced to flow the particles. Fluidized bed) [Materials Letters, Vol 19, No 3/4 (1994), Powder Tech. Vol 88, No. 1 (1996).

However, these methods have a problem in that the apparatus is complicated or ineffective for relatively large particles (tens of tens of mu m to several mm in size).

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a CVD diamond synthesizing apparatus capable of uniform diamond film coating on a particulate base material when relatively large particles (tens of tens of micrometers to several millimeters in size) are used. There is a purpose.

The CVD diamond synthesis apparatus of the present invention for achieving this object,

CVD diamond synthesis container having a rotatable substrate support, and a tilt mechanism capable of fixing the container in an inclined state such that the surface supporting the substrate of the substrate support is inclined with respect to the reference surface (bottom surface). .

Here, the tilting mechanism includes a tower portion coupled to at least one side of the vessel, and a support portion connected to the tower portion to support the tower portion to stand, wherein the tower portion has a plurality of coupling points on one side of the vessel. Is coupled, but one of the plurality of coupling points is fixed.

Alternatively, the tilting mechanism includes an auxiliary mechanism coupled to at least one side of the container, a tower portion coupled to the auxiliary mechanism at a plurality of coupling points, and a support portion connected to the tower portion to support the tower portion to stand. One of the plurality of coupling points is fixed.

In addition, the angle formed between the axis of rotation of the substrate support and the vertical axis of the reference plane is preferably 0 to 45 degrees.

Features of the CVD diamond synthesis apparatus according to the present invention,

First, a mechanism capable of tilting the axis of rotation of the substrate support (which coincides with the central axis of the diamond synthesis vessel when the surface supporting the substrate on the substrate support is horizontally positioned in the vessel) from 0 to 45 ° from the vertical axis of the synthesis apparatus It is installed.

Second, a mechanism for rotating the substrate support (the portion where the substrate is placed in the diamond synthesis container) is mounted.

Third, a locking jaw is formed around the edge of the upper surface of the substrate support, so that the substrate does not slip out of the substrate support when the container for diamond synthesis is inclined.

By modifying the existing CVD diamond synthesis apparatus (hot-filament CVD, DC power plasma CVD, microwave plasma CVD), DC power arc jet, etc. to have the above mechanisms, This provides a CVD diamond synthesis apparatus capable of uniform diamond film coating on the particles.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 1 shows a conceptual diagram of a diamond synthesis apparatus capable of uniform diamond coating on the particulate base material according to the present invention. The diamond synthesis apparatus includes a power supply, a vacuum pump, a gas supply, and the like, but is not shown for convenience. 1 (a) shows a state in which the central axis (L) of the vacuum chamber for diamond synthesis (1) forms a predetermined angle (θ) with the vertical axis (M) of the synthesizing apparatus. Figure 1 (b) schematically shows a cross section viewed from the right angle direction of (a). That is, if FIG. 1A is a side view, FIG. 1B is a front sectional view.

Referring to Fig. 1, in the CVD diamond synthesis apparatus according to the present invention, a container for CVD diamond synthesis having a rotatable substrate support 11 and a surface for supporting the substrate of the substrate support are a reference plane (bottom surface). Or a tilting mechanism which can be fixed in an inclined state so that the container is tilted with respect to the horizontal plane.

Here, the tilt mechanism may take a variety of structures, the tilt mechanism includes a tower portion 2 coupled to at least one side of the container, and a support portion 3 connected to the tower portion to support the tower portion to stand. It may include. In FIG. 1 the tilting mechanism further comprises an auxiliary mechanism coupled to one side of the vessel 1 to mediate the engagement between the tower portion 2 and the vessel 1.

More specifically, two tower parts 2 stand perpendicular to the base 3 which is flat on the reference plane (bottom or horizontal). On the other hand, two auxiliary mechanisms 4 are respectively coupled in the longitudinal direction to the central portions of both sides of the container 1. Each tower portion 2 and the corresponding auxiliary mechanism 4 form a coupling point at the upper and lower portions. Looking at the shape of the tower portion 2 in detail, the upper coupling point has a coupling point for the tower portion 2. Although the position of the coupling point of the auxiliary mechanism 4 is fixed without being fixed, the position of the coupling point of the auxiliary mechanism 4 can be changed with respect to the coupling point of the tower portion 2 at the lower coupling point. Make a mobile coupling. That is, the tower portion 2 is fastened using the fixing wedge 6 to one of the plurality of fixing grooves 5-1 formed in the connector 5 connected to the auxiliary mechanism, and the plurality of fixing grooves to be fastened. By selecting any one of (5-1), the angle θ formed between the central axis L of the container 1 and the vertical axis M of the synthesis apparatus is adjusted.

Alternatively, although not shown in the drawings, various tilting mechanisms including no auxiliary mechanisms may be devised. For example, the coupling point of the upper part of the plurality of coupling points to which the tower unit and the container are coupled is fixed to the upper part of the container side, and the lower coupling point is moved along a certain trajectory at the lower part of the container side to adjust the angle.

However, the content of the present invention is not limited to the structure of the tilt mechanism described above, and any other structure capable of fixing the container 1 for diamond synthesis in an inclined state may be adopted.

On the other hand, the plasma 8 is formed inside the vacuum vessel 1 as in a general diamond synthesizing apparatus. The base material particles 9 are placed on the substrate 10, which is placed on the substrate support 11. Under the vacuum container 1, a rotating mechanism (eg, a motor) 12 capable of rotating the substrate support is provided. Referring to FIG. 1B, the motor 12 interlocks a motor gear 12-1 connected thereto and a shaft gear 11-3 interlocked with the shaft 11-2 of the substrate support 11. The substrate support 11 is rotated on a horizontal plane.

2 is a schematic diagram showing the base material particles placed on the substrate. In this embodiment, it is assumed that the surface supporting the substrate of the substrate support is positioned horizontally in the container for diamond synthesis. Accordingly, the rotation axis of the substrate support 11 in FIG. 2 coincides with the central axis of the container 1 for diamond synthesis in FIG. 1. 2A is a state in which the rotation axis of the substrate support 11 or the central axis L of the container for diamond synthesis is perpendicular to the reference plane (bottom surface, horizontal plane), and (B) the substrate support 11 ) Shows a state in which the rotation axis L of () maintains a constant angle θ from the vertical axis M of the synthesis apparatus. In this case, the base material particles 9 are oriented in one direction of the substrate 10 due to gravity. When the substrate support is rotated while maintaining this state, the base material particles are moved along the direction of rotation by gravity.

FIG. 3 is a schematic view of the deformable substrate 13 fabricated to alleviate the pulling phenomenon of the base material particles 9 shown in FIG. 3A is a plan view, and (B) is a cross-sectional view taken along the dotted line shown in (A). A section was made by making a circular groove 13-1 of a certain depth in the bottom of the substrate. The depth of the groove is preferably 10-30% of the base material particle size (diameter), but is not limited thereto (the depth of the groove should be lower than the particle size). In this embodiment, the shape of the groove in the modified substrate is circular, but is not limited thereto. In addition, by forming a locking step of a predetermined height smaller than the size of the base material particles on the edge of the upper surface of the substrate may prevent the separation of the base material particles due to the inclination of the substrate.

FIG. 4 shows the movement of the base material particles with the container tilted on the deformable substrate 13 shown in FIG. 3. 4 (a) shows the case where the center axis of the container is vertical, (b) and (c) shows the case where the center axis of the container 1 is inclined at an angle with respect to the vertical axis of the synthesis apparatus. . In the case of maintaining the state of (b) and rotating the substrate support, the movement of the base material particles is limited to each groove, so that the phenomenon of the base material particles is greatly alleviated.

Hereinafter, the present invention will be described in more detail with reference to specific examples, but the scope of the present invention is not limited to the following examples.

Example 1.

Based on the next pole DC power plasma CVD apparatus (with all the equipment necessary for the synthesis of the diamond, including the substrate support in the vacuum vessel of the apparatus), as shown in FIG. A CVD diamond synthesis apparatus with a tiltable vacuum vessel was fabricated. The maximum angle at which the central axis of the vacuum vessel can be tilted from the vertical axis of the synthesizing apparatus (vertical axis of the reference plane) is 45 °. Tilts above 45 ° have no effect. In fact, in Table 1, the particles did not move even when tilted at 50 to 90 ° for small particles of 30 μm or less. In addition, there is a risk that the larger the angle becomes unstable equipment. On the other hand, the lower part of this container was equipped with the motor for rotating a substrate support. At the edge of the upper surface of the substrate support, a latching jaw (height 1 mm) capable of fixing a substrate having a diameter of 100 mm was made.

Example 2.

Using the apparatus of Example 1 and placing a 100 mm diameter molybdenum substrate shown in FIG. 2, the influence of the size of the base material particles on the movement of the particles according to the tilt angle of the vacuum vessel was investigated. The matrix particles used were sphere-shaped silicas of 0.01, 0.03, 0.05, 0.075, 0.1, 0.2, 0.5, 1, 2, 3, 5 mm in diameter, and the substrate support rotation speed was 1 rpm. The results are shown in Table 1. The movement of these particles will change depending on the physical and chemical states of the substrate and the surface of the particles, and on external vibrations (vibrations not intentionally applied).

Particle Movement Depending on the Tilt Angle and Particle Size of the Vacuum Vessel Particle Diameter (mm) Angle (°)  0.01  0.03  0.05  0.75  0.1  0.2  0.5  One  2  3  5 10 × × × × × × ○ ○ ○ ○ ○ 20 × × × × ○ ○ ○ ○ ○ ○ ○ 30 × × × ○ ○ ○ ○ ○ ○ ○ ○ 45 × × ○ ○ ○ ○ ○ ○ ○ ○ ○

(○: movement, ×: do not move)

Example 3.

Diamond synthesis experiments were carried out using a vapor phase chemical vapor deposition diamond synthesis apparatus having a tiltable vacuum vessel produced in Example 1, using porous silica spheres having a diameter of 2 mm as base material particles.

Porous silica spheres were subjected to pretreatment (sonic vibration treatment for 1 hour with particles in an alcohol solution containing 1 μm diamond fine powder) to facilitate diamond synthesis. At this time, by attaching a tape having a diameter of 100 ㎛ to a portion of the surface to block (blocking) to prevent the pretreatment liquid (the specific method for this is described in detail in the Republic of Korea Patent Application No. 2005-0030824), Diamonds were not formed. The number of base material particles was adjusted to occupy about 80% of the surface of the substrate. Diamond synthesis conditions were 15 kW input power, 10% methane composition in hydrogen gas, 100 Torr pressure, 200 sccm gas flow rate. Synthesis time was 10 hours. During synthesis, the angle of the vacuum vessel was maintained at 20 °, and the substrate support was continuously rotated at a speed of 1 rpm.

During this experiment, the substrate particles continually moved to the lower side of the substrate and no problems with the unusual device were found. The synthesized particles appeared black and the size was about 2.2 mm. As a result of observing each particle under a stereoscopic microscope, it was found that a uniform film was formed as a whole, and diamond undeposited portions of 10 to 20 μm could be confirmed. As a result of observing the surface of the particles using a scanning electron microscope, it was confirmed that a uniform diamond film was deposited as a whole, and the (100) and (111) planes were mixed. This diamond / silica complex was held in a boiling Murakami solution for about 10 minutes. The color of the particles turned gray. This is because the silica matrix layer and the silicon carbide layer formed at the diamond interface were etched and removed by the capillary assisting etching through the non-diamond deposited portion. This experiment produced a diamond shell having a size of 2.2 mm in diameter.

Example 4.

A diamond synthesis experiment was conducted under the same conditions as in Example 3, using a strained substrate having a diameter of 100 mm (16 mm in the groove diameter and 1 mm in the groove depth) shown in FIG. The matrix particles used were porous silica spheres with a diameter of 3 to 5 mm and subjected to the same selective pretreatment as in Example 1. Ten grooves were placed in each groove. The vacuum vessel was tilted at 15 °. During the synthesis, the substrate support was continuously rotated at a speed of 1.5 rpm, and the matrix particles were well oriented to one side within each groove. The synthesized complex increased in size by about 200 μm and the surface texture of the complex was similar to that of Example 3.

As described above, the diamond synthesizing apparatus having a tiltable vacuum container of the present invention enables a simple diamond coating on the particulate base material. This diamond synthesizing apparatus can be used for diamond coating for producing diamond shells of several tens of micrometers to 5 mm in size, which can be applied to capsules for inertial confinement fusion.

Claims (9)

A CVD diamond synthesis vessel having a substrate support; A rotating mechanism for rotating the substrate support; And a tilting mechanism for fixing the container so that the upper surface of the substrate support is inclined with respect to the ground during CVD diamond synthesis. CVD diamond synthesis apparatus. The method of claim 1, The tilt mechanism includes a tower portion coupled to at least one side of the container, and a support portion connected to the tower portion to support the tower portion to stand. And the tower portion is coupled to one side of the vessel at a plurality of bonding points, but one of the plurality of bonding points is fixed. The method of claim 1, The tilt mechanism includes an auxiliary mechanism coupled to at least one side of the container, a tower portion coupled to the auxiliary mechanism at a plurality of coupling points, and a support portion connected to the tower portion to support the tower portion to stand. CVD diamond synthesis apparatus, characterized in that one of the plurality of joining points is fixed. The method of claim 1, The angle formed between the axis of rotation of the substrate support and the vertical axis of the reference plane is greater than 0 ° and less than 45 °. The method of claim 1, CVD diamond synthesis apparatus, characterized in that the locking step is formed on the edge of the upper surface of the substrate support. The method of claim 1, And the synthesizing apparatus further comprises a substrate overlying the substrate support. The method of claim 6, CVD diamond synthesis apparatus, characterized in that the locking step is formed on the edge of the upper surface of the substrate. The method of claim 6, And a plurality of grooves having a predetermined depth is formed on the upper surface of the substrate. delete

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