Chamber structure for microwave plasma chemical vapor deposition apparatus

Abstract

This invention provides a chamber structure for a microwave plasma chemical vapor deposition apparatus that prevents the formation of two strong field regions in the microwave field, thereby avoiding the occurrence of the "double fireball phenomenon." [Solution] A chamber structure for a microwave plasma chemical vapor deposition apparatus, the chamber structure includes a housing 10 and a stage 30, the housing including an inner bottom surface 21, an inner top surface 22 and an inner ring wall surface 23. The inner bottom surface 21 and the inner top surface 22 are spaced apart from each other and face each other, the diameter of the inner bottom surface 21 is larger than the diameter of the inner top surface 22, and the inner top surface 22 protrudes toward the inner bottom surface 21. Both ends of the inner ring wall surface 23 are connected to the inner top surface 22 and the inner bottom surface 21, respectively, so that a chamber 20 is formed between the inner bottom surface 21, the inner top surface 22 and the inner ring wall surface 23, and the microwave field is located in the chamber 20. The stage 30 is provided in the chamber and has a stage surface facing the inner top surface 22.

Description

Technical Field

[0001] The present invention relates to a member of a microwave plasma chemical vapor deposition apparatus, and more particularly to a chamber structure for a microwave plasma chemical vapor deposition apparatus.

Background Art

[0002] Microwave plasma assisted chemical vapor deposition (MPCVD) is a method of chemical vapor deposition. A strong field is formed in a microwave field by microwaves to excite and dissociate reaction gases, thereby generating a high-temperature fireball in a plasma state. At this time, the free atoms are guided and adhere to a specified object, and a specific structure is formed by depositing according to a specific atomic arrangement. One of the common uses of MPCVD is the production of artificial diamonds. A high-temperature plasma is generated with hydrogen gas, carbon atoms in methane are liberated, and the carbon atoms are deposited on a seed crystal to form diamond crystals according to a specific atomic arrangement. Currently, there are mainly three types of MPCVD apparatuses on the market, namely, a cylindrical chamber type, a French type, and a disk type chamber structure. Among them, the disk type chamber structure has various designs.

[0003] Figure 5 shows the design of a conventional disk-type chamber structure 90 in an MPCVD apparatus. This MPCVD apparatus is widely used because of its good uniformity of microwave fields. However, inside the chamber structure 90, except for the growth region 92 above the growth stage 91, a strong field region 93 is further formed near the top of the microwave field chamber. As a result, when using this MPCVD apparatus, the "double fireball phenomenon," in which fireballs are formed simultaneously above and below, frequently occurs, hindering deposition. Furthermore, in the conventional disk-type chamber structure 90, the height of the growth region 92 formed above the microwave field growth stage 91 is high, and the contact area between the bottom of the growth region 92 and the growth stage 91 is narrow. Therefore, the growth rate during the deposition process does not match between the outer periphery and the central part of the semi-finished product, causing stress inside the product and leading to rupture.

[0004] In light of the above issues, the conventional disk-type chamber structure in the aforementioned MPCVD apparatus clearly needs improvement. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Taiwan Public Notice No. TW I202134473A [Overview of the project] [Problems that the invention aims to solve]

[0006] The main object of the present invention is to provide a chamber structure for a microwave plasma chemical vapor deposition apparatus, which prevents the formation of two strong field regions in the microwave field during use and avoids the occurrence of the "double fireball phenomenon". [Means for solving the problem]

[0007] To achieve the above objective, the chamber structure for the microwave plasma chemical vapor deposition apparatus of the present invention is as follows: A chamber structure for a microwave plasma chemical vapor deposition apparatus for forming a microwave field using microwaves, Including housing and stage, The aforementioned housing is An inner bottom surface and an inner top surface that are spaced apart from each other and facing each other, wherein the diameter of the inner bottom surface is greater than the diameter of the inner top surface, and the inner top surface protrudes toward the inner bottom surface, An inner ring wall surface, the ends of which are connected to the inner top surface and the inner bottom surface respectively, so that a chamber is formed between the inner bottom surface, the inner top surface and the inner ring wall surface, and the microwave field is located in the chamber, including the inner ring wall surface, The stage is provided in the chamber and has a stage surface facing the inner top surface.

[0008] The advantage of the present invention lies in the fact that the microwave field generated by the microwaves forms a strong field growth region on the stage. According to the shape of the chamber of the present invention, since the growth region is located below the inner top surface, the microwave field does not form another strong field region above the growth region on the protruding inner top surface. Therefore, the chamber structure of the present invention can prevent the "double fireball phenomenon" from occurring.

[0009] A chamber structure for a microwave plasma chemical vapor deposition apparatus according to one embodiment of the present invention is characterized in that the inner top surface is an arc-shaped surface.

[0010] In a chamber structure for a microwave plasma chemical vapor deposition apparatus according to one embodiment of the present invention, the portion of the chamber surrounded by the inner ring wall surface is characterized in that its inner diameter decreases as it moves from the inner bottom surface toward the inner top surface.

[0011] A chamber structure for a microwave plasma chemical vapor deposition apparatus according to one embodiment of the present invention is characterized in that the inner bottom surface is recessed in a direction away from the inner top surface.

[0012] In a chamber structure for a microwave plasma chemical vapor deposition apparatus according to one embodiment of the present invention, The aforementioned housing is The base member on which the inner bottom surface is located, A peripheral wall member is closely attached to the periphery of the base member and extends in a direction away from the base member, and the inner ring wall surface is located therein The present invention is characterized by having a canopy portion that is in close contact with the end of the peripheral wall member relative to the base member.

[0013] In a chamber structure for a microwave plasma chemical vapor deposition apparatus according to one embodiment of the present invention, The aforementioned housing is The present invention is characterized by having at least one gas inlet that penetrates the peripheral wall member and is located near the canopy portion.

[0014] In a chamber structure for a microwave plasma chemical vapor deposition apparatus according to one embodiment of the present invention, The invention is characterized by further comprising a microwave tube connected to the base member and communicating with the chamber.

[0015] In a chamber structure for a microwave plasma chemical vapor deposition apparatus according to one embodiment of the present invention, The canopy portion is characterized by being detachably connected to the peripheral wall member.

[0016] In a chamber structure for a microwave plasma chemical vapor deposition apparatus according to one embodiment of the present invention, The present invention further comprises a cooler that is drilled into the housing and connected to the stage.

[0017] In a chamber structure for a microwave plasma chemical vapor deposition apparatus according to one embodiment of the present invention, The band adopted for the microwave is between 900 megahertz (MHz) and 930 megahertz (MHz), or between 2400 megahertz (MHz) and 2500 megahertz (MHz), which is characterized by this.

Brief Description of the Drawings

[0018] [Figure 1] It is a perspective external view schematic diagram of the present invention. [Figure 2] It is a side cross-sectional schematic diagram of the present invention. [Figure 3] It is a partial enlarged schematic diagram of FIG. 2. [Figure 4] It is a schematic diagram of a microwave field formed by microwaves within the chamber structure of the present invention. [Figure 5] It is a schematic diagram of a microwave field formed by microwaves within a conventional disk-shaped chamber structure.

Modes for Carrying Out the Invention

[0019] As shown in FIGS. 1 to 4, the present invention provides a chamber structure for a microwave plasma chemical vapor deposition apparatus for forming a microwave field by microwaves. It is preferable to form a microwave field with microwaves whose frequency band is between 900 megahertz (MHz) and 930 megahertz (MHz), or between 2400 megahertz (MHz) and 2500 megahertz (MHz), but it is not limited to this.

[0020] The chamber structure for the microwave plasma chemical vapor deposition apparatus of the present invention includes a housing 10, a stage 30, a microwave tube 40, and a cooler 50.

[0021] The housing 10 includes an inner bottom surface 21, an inner top surface 22, and an inner annular wall surface 23. Both ends of the inner annular wall surface 23 are respectively connected to the inner bottom surface 21 and the inner top surface 22, so that a chamber 20 is formed to be surrounded by the inner bottom surface 21, the inner top surface 22, and the inner annular wall surface 23 together, and the microwave field by microwaves is located within the chamber 20.

[0022] The inner bottom surface 21 and the inner top surface 22 are positioned opposite each other with a gap between them. In this embodiment, the inner bottom surface 21 and the inner top surface 22 are circular surfaces, and the diameter of the inner bottom surface 21 is larger than the diameter of the inner top surface 22. As a result, the chamber 20 is formed in a disk shape with a narrow upper bottom surface and a wide lower bottom surface. The inner top surface 22 is a reflective surface for reflecting microwaves, and a structure is formed on the inner top surface 22 that protrudes in an arc shape toward the inner bottom surface 21. However, it is not limited to this, that is, the inner top surface 22 may have any other shape as long as it protrudes toward the inner bottom surface 21 and occupies a part of the space at the top of the chamber 20.

[0023] In this embodiment, the inner bottom surface 21 is further recessed in the direction away from the inner top surface 22. More specifically, the inner bottom surface 21 includes a peripheral portion 211 and a central portion 212. The peripheral portion 211 is connected to the central portion 212 so as to surround it, the central portion 212 is a flat surface, and the peripheral portion 211 is a slope. Furthermore, in the diametrical direction of the inner bottom surface 21, the peripheral portion 211 gradually slopes from the inside to the outside as it approaches the inner top surface 22, but is not limited to this, and the shape of the inner bottom surface 21 can be adjusted according to the needs.

[0024] In this embodiment, the portion of the chamber 20 enclosed by the inner ring wall 23 has an inner diameter that decreases as it moves from the inner bottom surface 21 towards the inner top surface 22. More specifically, as shown in Figure 3, the inner ring wall 23 gradually slopes inward as it moves from the inner bottom surface 21 towards the inner top surface 22, creating a shape like an inverted hopper, so that the chamber 20 takes on a shape like the apex of a cone has been cut off. However, it is not limited to this, and the shapes of the chamber 20 and the inner ring wall 23 can be adjusted according to the needs. For example, the inner ring wall 23 may be a curved surface with an arc-shaped edge in the height direction of the chamber 20, or it may be a stepped surface.

[0025] Furthermore, in this embodiment, the base member 11, the peripheral wall member 12, and the canopy portion 13 together form the housing 10, but the embodiment is not limited to this. Also, the inner bottom surface 21 is located on the base member 11, the inner ring wall surface 23 is located on the peripheral wall member 12, the inner top surface 22 is located on the canopy portion 13, the peripheral wall member 12 is in close contact with the periphery of the base member 11 and extends in a direction away from the base member 11, and the canopy portion 13 is in close contact with the end of the peripheral wall member 12 relative to the base member 11.

[0026] Preferably, the canopy portion 13 is detachably connected to the peripheral wall member and has an inner top surface 22 of a different shape, so that the user can easily replace the canopy portion 13 according to their needs, but it is not limited to this and other configurations are also possible.

[0027] The housing 10 has at least one gas inlet 121 through it. In this embodiment, the gas inlet 121 is formed in the peripheral wall member 12 and is located close to the canopy portion 13, but is not limited to this. For example, in other embodiments, it may be located in the canopy portion 13.

[0028] As shown in Figures 2 to 4, the stage 30 is provided in the chamber 20 and has a stage surface 31, which faces the inner top surface 22. The stage 30 is for placing a substrate (not shown), for example, a diamond seed crystal, which is placed on the stage surface 31 and below the inner top surface 22. In this embodiment, the stage 30 is provided at a distance from the inner bottom surface 21 and has a chamfered structure around its periphery, which facilitates the flow of the working gas (not shown) and the propagation of microwaves, thereby promoting the formation of a microwave field and a plasma fireball, but is not limited to this. The microwave tube 40 is connected to the base member 11 and communicates with the chamber 20, and microwaves enter the chamber 20 through the microwave tube 40. The cooler 50 is drilled into the housing 10 and connected to the stage 30. Specifically, the cooler 50 is a sealed flow path through which a cooling fluid flows, thereby dissipating heat and enabling control of the high-temperature plasma fireball, but it is not limited to this configuration.

[0029] As shown in Figures 3 and 4, when using the chamber structure of the present invention, the shape of the chamber 20 of the present invention creates a strong field growth region 60 on the stage 30 with the microwave field generated by the microwaves. Since this region is located below the inner top surface 22, the protruding inner top surface 22 prevents the microwave field from forming another strong field region above the growth region 60. Therefore, the chamber structure of the present invention prevents the occurrence of the "double fireball phenomenon" and reduces its influence on the microwave plasma chemical vapor phase growth reaction.

[0030] Furthermore, as shown in Figures 4 and 5, compared to the conventional technology, the chamber structure of the present invention allows for a flatter and wider growth region 60 formed by the microwave field. Also, when artificial diamonds are manufactured using the present invention and the conventional technology, the growth region 60 of the present invention is wider than that of the conventional technology. Therefore, even if the growth area is the same as that of conventional artificial diamonds, when growing using the present invention, the growth rate of the outer edge and the growth rate of the central strong field region have high consistency. In other words, the overall growth rate during the growth process has high consistency, which avoids uneven product thickness due to mismatch in growth rate and product rupture due to the resulting stress, thus improving product yield. Accordingly, the present invention can be applied to the growth of products with a larger area and can meet a wider range of market needs. [Explanation of Symbols]

[0031] 10 Housing 11 Base member 12 Peripheral wall member 121 Gas Inlet 13. Canopy 20 chambers 21 Inner bottom surface 211 Peripheral area 212 Central part 22 Inner top surface 23 Inner ring wall 30 stages 31 Stages 40 Microwave Tubes 50 cooler 60 Growth areas 90 Chamber Structure 91 Growth Stages 92 Growth areas 93 Strong field area

Claims

1. A chamber structure for a microwave plasma chemical vapor deposition apparatus for forming a microwave field using microwaves, Including housing and stage, The aforementioned housing is An inner bottom surface and an inner top surface that are spaced apart from each other and facing each other, wherein the diameter of the inner bottom surface is greater than the diameter of the inner top surface, and the inner top surface protrudes toward the inner bottom surface, An inner ring wall surface, the ends of which are connected to the inner top surface and the inner bottom surface respectively, so that a chamber is formed between the inner bottom surface, the inner top surface and the inner ring wall surface, and the microwave field is located in the chamber, including the inner ring wall surface, The chamber structure for a microwave plasma chemical vapor deposition apparatus is characterized in that the stage is provided in the chamber and has a stage surface facing the inner top surface.

2. The chamber structure for a microwave plasma chemical vapor deposition apparatus according to claim 1, characterized in that the inner top surface is an arc-shaped surface.

3. The chamber structure for a microwave plasma chemical vapor deposition apparatus according to claim 1, characterized in that the portion of the chamber surrounded by the inner ring wall surface has an inner diameter that decreases as it moves from the inner bottom surface toward the inner top surface.

4. The chamber structure for a microwave plasma chemical vapor deposition apparatus according to claim 1, characterized in that the inner bottom surface is recessed in a direction away from the inner top surface.

5. The aforementioned housing, The base member on which the inner bottom surface is located, A peripheral wall member is closely attached to the periphery of the base member and extends in a direction away from the base member, and the inner ring wall surface is located therein A chamber structure for a microwave plasma chemical vapor deposition apparatus according to any one of claims 1 to 4, characterized by having a canopy portion that is in close contact with the end of the peripheral wall member relative to the base member.

6. The aforementioned housing is The chamber structure for a microwave plasma chemical vapor deposition apparatus according to claim 5, further comprising at least one gas inlet that penetrates the peripheral wall member and is located near the canopy portion.

7. The chamber structure for a microwave plasma chemical vapor deposition apparatus according to claim 5, further comprising a microwave tube connected to the base member and communicating with the chamber.

8. The chamber structure for a microwave plasma chemical vapor deposition apparatus according to claim 5, characterized in that the canopy portion is detachably connected to the peripheral wall member.

9. A chamber structure for a microwave plasma chemical vapor deposition apparatus according to any one of claims 1 to 4, further comprising a cooler drilled in the housing and connected to the stage.

10. A chamber structure for a microwave plasma chemical vapor deposition apparatus according to any one of claims 1 to 4, characterized in that the bandwidth used in the microwave is between 900 megahertz (MHz) and 930 megahertz (MHz), or between 2400 megahertz (MHz) and 2500 megahertz (MHz).

Images