A ring-shaped electrostatic chuck for molecular beam epitaxy and vapor deposition system interconnection

Abstract

The utility model discloses a kind of ring-shaped electrostatic chuck for molecular beam epitaxy and gas deposition system interconnection, comprising: heating disc, adsorption ring and mounting plate;The mounting plate front is equipped with heating disc, the outer edge of heating disc is equipped with adsorption ring, the mounting plate back is equipped with power terminal post, one end of the power terminal post is connected with external electrode, the other end of power terminal post is through mounting plate, and is connected with adsorption ring, to realize that electric field is generated after adsorption ring power on, adsorption wafer edge.The utility model has the characteristics of compact structure, convenient to use, high reliability, by adsorption ring to the "waste area" of wafer edge is adsorbed, there is no electric field in wafer effective area, avoid due to wafer after growth is charged and damage effective area, meet the needs of wafer turning and transfer.

Description

Technical Field

[0001] This utility model relates to the field of crystal growth technology, specifically to a ring-shaped electrostatic chuck for interconnecting molecular beam epitaxy and vapor deposition systems. Background Technology

[0002] Metal-organic chemical vapor deposition (MOCVD) is a novel vapor phase epitaxial growth technique developed based on vapor phase epitaxy (VPE). Molecular beam epitaxy (MBE) is a physical deposition technique for compound semiconductor multilayer thin films. MOCVD and MBE are two commonly used epitaxial growth equipment in the semiconductor field, widely applied in optoelectronic and microelectronic chip development and mass production.

[0003] MOCVD technology uses organic compounds of Group III and II elements and hydrides of Group V and VI elements as crystal growth source materials. It performs vapor-phase epitaxy on a substrate via thermal decomposition reactions. The growth chamber vacuum level is around 100 Torr. It boasts advantages such as high growth rate, low cost, high control flexibility, good process repeatability, and relatively simple equipment structure, making it the most widely used epitaxial growth technology on the market. MBE (Metal-Based Epitaxy) is based on the principle that under ultra-high vacuum conditions, vapor generated by heating a furnace containing various desired components is straightened through a small aperture to form a molecular or atomic beam, which is directly sprayed onto a single-crystal wafer at an appropriate temperature. Simultaneously, the molecular beam is controlled to scan the wafer, allowing molecules or atoms to grow layer by layer on the wafer according to a crystalline arrangement to form a thin film. Due to its excellent material growth quality, precise material thickness control, and extremely high material purity during growth, it is suitable for low-temperature growth materials such as arsenides and antimony compounds. MOCVD and MBE also have their inherent drawbacks: MOCVD uses a gaseous source, which inevitably introduces impurities, and the low vacuum environment results in relatively poor film quality; MBE requires an ultra-high vacuum environment for material growth, so the growth rate is slow, and its operating costs are high and production efficiency is low, which has prevented it from being used on a large scale.

[0004] MOCVD and MBE have many overlaps in practical applications, and using an alternating MOCVD+MBE growth method can achieve complementary advantages. MOCVD and MBE are independent systems with significant differences in wafer support structures: in MOCVD, the wafer growth face is upward, with the back contact placed within small graphite disks, and these air-bearing driven rotating graphite disks are then placed within a larger graphite disk driven by a motor. In MBE, the wafer growth face is downward, with the edge contact placed within each wafer position on the molybdenum holder. Because there are also significant differences between the MOCVD graphite disks and the MBE molybdenum holders, during actual production, when the two devices are used alternately, the wafer needs to be flipped when transferring between MOCVD and MBE. Current solutions use mechanical clamping for transfer and flipping, which can easily damage the wafer during actual operation.

[0005] Chinese patent application CN116377572A discloses a vacuum interconnected sample transfer system for MOCVD and MBE sample interaction. The system uses an electrostatic chuck on a first robotic arm to grip and flip the wafer, and a second robotic arm to grip and transfer the wafer carrier. Taking MOCVD to MBE sample transfer as an example, the electrostatic chuck grips the front side of the wafer from the MOCVD graphite disk in a non-contact manner and flips it so that the wafer growth surface is facing down on the sample platform of the centering correction module. The wafer is then pushed by a clamping assembly to correct the centering position. Finally, the electrostatic chuck grips the back side of the wafer and transfers it to the MBE molybdenum carrier. During the positioning correction process, the wafer growth surface will inevitably slide and rub against the sample platform, which contradicts the original intention of using an electrostatic chuck to avoid wafer surface damage and contact contamination. Furthermore, because the electrostatic chuck is a full-disc structure, the wafer is charged after growth in the chamber, and an electric field exists within the entire diameter of the electrostatic chuck. This can damage the wafer during adsorption. In addition, the electrostatic chuck directly contacts the wafer growth surface, which can contaminate the wafer. Therefore, it can only adsorb the back side of the wafer.

[0006] After the wafer is grown by MOCVD, it reaches a high temperature of 700°C. Then, during the growth process in the MBE equipment, it reaches a high temperature of nearly 1000°C. When the wafer is transferred from MOCVD to the MBE equipment, if the temperature of the wafer surface changes from 700°C to room temperature and then from room temperature to 1000°C, the wafer will experience a large stress change, which may cause the wafer to be scrapped. Therefore, it is necessary to keep the wafer in a suitable temperature range during the intermediate process. Utility Model Content

[0007] The technical problem to be solved by this utility model is to provide a ring electrostatic chuck with a compact structure, convenient operation and uniform electrode arrangement for interconnecting molecular beam epitaxy and vapor deposition systems, which addresses the shortcomings of the existing technology.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: An annular electrostatic chuck for interconnecting a molecular beam epitaxy and vapor deposition system includes: a heating plate, an adsorption ring, and a mounting plate; the heating plate is provided on the front side of the mounting plate, the adsorption ring is provided on the outer edge of the heating plate, and a power terminal is provided on the back side of the mounting plate. One end of the power terminal is connected to an external power source, and the other end of the power terminal passes through the mounting plate and is connected to the adsorption ring, so that an electric field is generated when the adsorption ring is energized, thereby adsorbing the edge of the wafer. As a further improvement of this utility model, the adsorption ring is provided with a positive conductive area, an insulating layer and a negative conductive area in sequence. Both the positive and negative conductive areas are connected to an external power source through power terminals. When the positive and negative conductive areas are energized, static electricity is generated to adsorb the edge of the wafer. As a further improvement of this utility model, the width of the adsorption ring is d=3±0.1mm and the thickness of the adsorption ring is h=0.3±0.01mm.

[0009] As a further improvement of this utility model, the heating plate is made of tungsten-doped material.

[0010] As a further improvement of this utility model, the mounting plate is made of ceramic material.

[0011] As a further improvement of this utility model, the mounting plate is provided with a plurality of mounting holes.

[0012] As a further improvement of this utility model, multiple temperature measuring points are evenly distributed on the heating plate.

[0013] Compared with the prior art, the advantages of this utility model are: This invention relates to a ring-shaped electrostatic chuck for interconnecting molecular beam epitaxy (MBE) and chemical vapor deposition (MBE) systems. A heating plate is positioned on the front of a mounting plate, and an adsorption ring is placed on the outer edge of the heating plate. The adsorption ring is connected to an external power source via a power terminal. When the heating plate is energized, it heats the wafer. When the adsorption ring is energized, it generates an electric field that adsorbs ineffective waste areas at the wafer edge. The heating plate does not need to contact the effective area of ​​the wafer, avoiding direct contact with the wafer surface and thus preventing contamination. Since only the outer ring has electrodes, the inner heating plate area has zero electric field, preventing damage to the wafer from electric fields. Because there is no need to clamp the wafer's periphery, the risk of fragmentation due to compressive stress is reduced. The wafer is transferred separately from the MOCVD system to the MBE system, avoiding contamination from unnecessary materials such as graphite. During the transfer from MOCVD growth to MBE for high-temperature growth, the electrostatic chuck maintains the wafer at a constant high temperature, ensuring that the wafer is not damaged by stress changes due to temperature variations. This invention's annular electrostatic chuck enables clean, efficient, and safe transfer of wafers between carriers of different specifications, achieving bidirectional automatic sample transfer from MOCVD to MBE or from MBE to MOCVD. It truly realizes vacuum interconnection and process interconnection between MOCVD and MBE, giving full play to the advantages of both devices, significantly improving process performance and production efficiency, and providing possibilities for the development of special materials and new devices. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structural principle of the annular electrostatic chuck used for interconnecting the molecular beam epitaxy and vapor deposition systems in a specific embodiment of this utility model; Figure 2 This is a schematic diagram of the structural principle of the annular electrostatic chuck used for interconnecting the molecular beam epitaxy and vapor deposition system in a specific embodiment of this utility model from another perspective. Figure 3 for Figure 2 Schematic diagram of electric field distribution along the AA direction; Figure 4 for Figure 2 A schematic diagram of the structural principle at point B; Legend: 1. Power terminal; 2. Heating plate; 3. Adsorption ring; 4. Mounting plate; 5. Mounting hole; 6. Positive conductive area; 7. Insulating layer; 8. Negative conductive area. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention.

[0016] In the description of this utility model, it should be understood that the terms "side", "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0017] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "multiple" means two or more, unless otherwise explicitly specified.

[0018] Example like Figure 1 and Figure 2 As shown, the annular electrostatic chuck of this invention for interconnecting molecular beam epitaxy and vapor deposition systems includes: a heating plate 2, an adsorption ring 3, and a mounting plate 4. The mounting plate 4 is made of high-temperature resistant ceramic material, making it well-suited for ultra-high vacuum and high-temperature environments, and resistant to corrosion from plasma or chemical gases. Multiple mounting holes 5 are evenly distributed on the mounting plate 4 to facilitate the overall mounting of the annular electrostatic chuck onto the working mechanism.

[0019] A heating plate 2 is provided on the front of the mounting plate 4. The heating plate 2 is made of tungsten-doped material and can heat up to 300℃. Multiple temperature measuring points (not shown in the figure) are evenly distributed on the heating plate 2, and the temperature control accuracy can reach ±0.1℃, improving the uniformity of wafer heating. The specific working principle of the heating plate 2 can adopt conventional settings in the field and will not be described in detail here. An adsorption ring 3 is provided on the outer edge of the heating plate 2. A power terminal 1 is provided on the back of the mounting plate 4. One end of the power terminal 1 is connected to an external power source, and the other end of the power terminal 1 passes through the mounting plate 4 and is connected to the adsorption ring 3. When the adsorption ring 3 is energized, an electric field is generated, which then adsorbs the edge of the wafer. This satisfies the requirements of wafer adsorption and transfer, and also ensures that the wafer is kept heated during the transfer process. Moreover, the adsorption electrode is set in the outer annular area, while there is no electric field in the inner circular area, avoiding damage to the wafer caused by the electric field. like Figure 3 and Figure 4As shown, the adsorption ring 3 has a positive conductive region 6, an insulating layer 7, and a negative conductive region 8 arranged sequentially from the inside to the outside. Both the positive conductive region 6 and the negative conductive region 8 are connected to an external power supply through power terminals 1. Several positive electrodes are evenly distributed in the positive conductive region 6, and several negative electrodes are evenly distributed in the negative conductive region 8. The positive and negative electrodes are separated by the insulating layer 7 to prevent short circuits. The charging principle of the adsorption ring 3 is the same as that of a capacitor. The positive conductive region 6 and the negative conductive region 8 are the two charged plates of the capacitor. When the positive conductive region 6 and the negative conductive region 8 are energized, the positive conductive region 6 carries a large amount of positive charge, and the negative conductive region 8 carries a large amount of negative charge. Since there are a large number of free positive and negative charges on the wafer, a large number of negative charges will accumulate on the wafer surface in contact with the positive conductive region 6. The positive charge on the positive conductive region 6 and the negative charge accumulated on the wafer surface attract each other, and finally, the wafer will be adsorbed onto the adsorption ring 3. The ring design of adsorption ring 3, combined with multi-electrode zone control, can evenly distribute electrostatic force, ensuring uniform stress on the wafer and reducing warpage or deformation. The adsorption force can also be adjusted via DC or AC voltage to avoid discharge damage caused by electrostatic accumulation.

[0020] like Figure 1 and Figure 4 As shown, the width of the adsorption ring 3 is d=3mm, and the thickness of the adsorption ring 3 is h=0.3mm. The electric field exists within the 3mm region of the adsorption ring 3, while there is no electric field in the region of the heating plate 2. Because the 5mm region at the edge of the wafer has a "waste area" due to uneven growth, the annular electrostatic chuck will not damage the effective area due to the wafer becoming charged after growth.

[0021] It should be noted that the annular electrostatic chuck in this embodiment is mainly suitable for 4-inch wafers. Other carrier combinations, such as 8-inch, 6-inch, 3-inch, and 2-inch wafers, can also adopt the solution of this embodiment, only requiring changes to the corresponding parameters.

[0022] The above description is merely a preferred embodiment of this utility model. The protection scope of this utility model is not limited to the above embodiments. All technical solutions falling within the scope of this utility model's concept are protected. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of this utility model should also be considered within the protection scope of this utility model.

Claims

1. A ring-shaped electrostatic chuck for interconnecting a molecular beam epitaxy and vapor deposition system, characterized in that, include: Heating plate (2), adsorption ring (3) and mounting plate (4); the mounting plate (4) has heating plate (2) on the front and adsorption ring (3) on the outer edge of heating plate (2). The mounting plate (4) has power terminal (1) on the back. One end of power terminal (1) is connected to an external power source and the other end of power terminal (1) passes through the mounting plate (4) and is connected to adsorption ring (3) so that an electric field is generated after the adsorption ring (3) is energized, and the edge of the wafer is adsorbed.

2. The annular electrostatic chuck for interconnecting a molecular beam epitaxy and vapor deposition system according to claim 1, characterized in that, The adsorption ring (3) is provided with a positive conductive area (6), an insulating layer (7) and a negative conductive area (8) in sequence. The positive conductive area (6) and the negative conductive area (8) are connected to an external power source through a power terminal (1). When the positive conductive area (6) and the negative conductive area (8) are energized, static electricity is generated to adsorb the edge of the wafer.

3. The annular electrostatic chuck for interconnecting a molecular beam epitaxy and vapor deposition system according to claim 2, characterized in that, The width of the adsorption ring (3) is d=3±0.1mm and the thickness of the adsorption ring (3) is h=0.3±0.01mm.

4. The annular electrostatic chuck for interconnecting a molecular beam epitaxy and vapor deposition system according to any one of claims 1 to 3, characterized in that, The heating plate (2) is made of tungsten-doped material.

5. The annular electrostatic chuck for interconnecting a molecular beam epitaxy and vapor deposition system according to any one of claims 1 to 3, characterized in that, The mounting plate (4) is made of ceramic material.

6. The annular electrostatic chuck for interconnecting a molecular beam epitaxy and vapor deposition system according to any one of claims 1 to 3, characterized in that, The mounting plate (4) has multiple mounting holes (5) evenly distributed on it.

7. The annular electrostatic chuck for interconnecting a molecular beam epitaxy and vapor deposition system according to any one of claims 1 to 3, characterized in that, Multiple temperature measuring points are evenly distributed on the heating plate (2).

Images