Susceptor for high temperature processes

Abstract

To provide a susceptor structure that can suppress deterioration of the joint between a ceramic and a base during high-temperature processes, and a susceptor with a structure that allows individual temperature control for multiple heating zones while using AlN material with high thermal conductivity as a ceramic material.SOLUTION: An electrostatic chuck 100 as a susceptor includes a base member 120 having a first cooling gas flow path 122 for allowing a cooling gas to flow in, a heat insulating member 130 having a thermal conductivity of 20 W / mK or less and stacked on the base member, the heat insulating member 130 has a second cooling gas flow path 132 communicating with the first cooling gas flow path, and an insulating plate 110 stacked on the heat insulating member and having a plurality of gas holes 112 communicating with the second cooling gas flow path to eject a cooling gas for cooling the substrate.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to susceptors, and more particularly to susceptors for supporting substrates in high temperature semiconductor processes. [Background technology]

[0002] Semiconductor devices and display devices are manufactured by depositing and patterning multiple thin film layers, including dielectric layers and metal layers, on glass substrates, flexible substrates, or semiconductor wafer substrates through semiconductor processing such as chemical vapor deposition (CVD), physical vapor deposition (PVD), ion implantation, and etching processes. Chambers for carrying out these semiconductor processes use susceptors to support various substrates, such as glass substrates, flexible substrates, and semiconductor wafer substrates. A representative example of such susceptors is an electrostatic chuck (ESC), which secures the substrate using electrostatic force.

[0003] FIG. 1 is a diagram schematically illustrating an example of a conventional electrostatic chuck.

[0004] Referring to FIG. 1, the electrostatic chuck comprises a base 20 and an insulating plate 10 on the base.

[0005] The insulating plate 10 may be made of a ceramic material such as alumina, and may have electrodes 14, such as DC electrodes, heater electrodes, and / or RF electrodes, embedded therein.

[0006] In order to uniformly cool the substrate on the insulating plate 10, the base 20 and the insulating plate 10 bonded thereto are provided with a predetermined cooling structure. Cooling gas flowing in through the cooling gas flow passages 22 provided in the base 20 communicates with the gas holes 12 of the insulating plate 10 to cool the substrate. In such a conventional electrostatic chuck structure, the base 20 and the insulating plate 10 are bonded together with an adhesive layer 30.

[0007] The manufacturing process of semiconductor devices using such electrostatic chucks is gradually progressing in a direction in which the aspect ratio of devices continues to increase by stacking fine patterns to an ultra-high level.

[0008] In semiconductor processes, fabricating high aspect ratio patterns leads to increased plasma voltage and process time, and the application of durable hard masks is essential, especially for NAND processes with 200 or more layers. As a result, materials with excellent plasma resistance, such as boron-doped amorphous carbon layer and silicon oxynitride, are being adopted as hard mask materials for next-generation processes, which is making the etching process for etching the hard mask layer more difficult.

[0009] To improve the reactivity and selectivity required for the etching process of etching the hard mask layer, the electrostatic chuck must operate at high temperatures of over 300°C. However, conventional electrostatic chucks use organic materials such as silicone as an adhesive between the ceramic and metal body, which deteriorates and decomposes at high temperatures, making it difficult to maintain adhesive strength at the process temperature.

[0010] Furthermore, conventional electrostatic chucks have a high linear thermal expansion coefficient between the ceramic and metal base, which causes a large stress in the adhesive layer between the base and plate during high temperature processes.

[0011] Meanwhile, to raise the temperature of an electrostatic chuck suitable for high-temperature processes, it is preferable to use a material with high thermal conductivity, such as AlN. However, because AlN has a high thermal conductivity of 180 kW / m K, it is difficult to control the temperature by dividing the heating area within the electrostatic chuck. Summary of the Invention [Problem to be solved by the invention]

[0012] SUMMARY OF THE INVENTION In order to solve the above-mentioned problems of the prior art, an object of the present invention is to provide a susceptor structure that can suppress deterioration of the joint between the insulating plate and the base during high-temperature processes.

[0013] Another object of the present invention is to provide a susceptor based on a non-bonded structure between an insulating plate and a base, which is suitable for application in high temperature processes.

[0014] Another object of the present invention is to provide a susceptor that uses AlN, a ceramic material with high thermal conductivity, and has a structure that allows individual temperature control for a plurality of heating zones. [Means for solving the problem]

[0015] In order to achieve the above technical objectives, the present invention provides a susceptor including: a base member having a first cooling gas flow path for introducing a cooling gas; a heat insulating member having a thermal conductivity of 20 W / mK or less and stacked on the base member, the heat insulating member having a second cooling gas flow path communicating with the first cooling gas flow path; and an insulating plate stacked on the heat insulating member, the heat insulating member having a plurality of gas holes communicating with the second cooling gas flow path and ejecting a cooling gas for cooling a substrate.

[0016] In the present invention, the heat insulating member may be made of quartz or may include any one material selected from the group consisting of Kovar, Ti, and Hastelloy.

[0017] In the present invention, the heat insulating member may be a rigid plate.

[0018] In the present invention, the base member may be a metal matrix composite (MMC) or aluminum.

[0019] In the present invention, the insulating plate preferably has a thermal conductivity of 50 W / mK or less at 300°C. In this case, the insulating plate may be made of an aluminum nitride material and may further contain Mg and Ti. In this case, it is preferable that the Mg content in the aluminum nitride material is 1 to 3 wt% in terms of MgO, and the Ti content is 0.1 to 0.5 wt% in terms of TiO2.

[0020] In the present invention, the heat insulating member preferably has a thermal conductivity at 300° C. of 20 W / mK or less.

[0021] In the present invention, the heat insulating member preferably has a thermal expansion coefficient at 300° C. of 10 μm / mK or less.

[0022] In the present invention, the first surface of the insulating member that contacts the base member and the second surface of the insulating member that contacts the insulating plate may each include an outer O-ring that is arranged along the outer periphery of the laminated structure.

[0023] In addition, the present invention may include a plurality of fastening devices that penetrate the laminated structure vertically and join it in the outer shell of the laminated structure, and the outer shell O-ring may be arranged inside the plurality of fastening devices.

[0024] In the present invention, the susceptor may include gas holes in the insulating plate for cooling the substrate on the insulating plate, and the gas holes may be in communication with the cooling gas communication holes in the base member.

[0025] In the present invention, the insulating member has a first surface that contacts the base member and a second surface that contacts the insulating plate, and the first and second surfaces of the insulating member can each be provided with an O-ring for sealing the second cooling gas flow path. [Effects of the Invention]

[0026] The present invention provides a susceptor structure that can suppress deterioration of the bonded portion between the ceramic and the base during high-temperature processes. Also, the present invention provides a susceptor that uses AlN, a ceramic material with high thermal conductivity, and has a structure that allows individual temperature control for multiple heating zones. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 is a diagram schematically illustrating a conventional susceptor structure. [Figure 2] FIG. 1 is a diagram schematically illustrating a susceptor structure according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Generally, the nomenclature used herein is one that is well known and commonly used in the art.

[0029] Throughout this specification, when a part "comprises" a certain component, this does not mean that it excludes other components, but that it may further contain other components, unless otherwise specified. Furthermore, in this specification, the expression "material A" is used to mean not only a material consisting of substance A alone, but also a material in which substance A is the main component (a component of 50% or more by weight) but is mixed with other materials other than substance A, or a composite material of substance A and other materials. Furthermore, in this invention, the term "laminated" can refer to a state in which two adjacent layers are in direct contact with each other, or a state in which they are not in contact with each other through another layer.

[0030] FIG. 2 is a cross-sectional view illustrating the structure of an electrostatic chuck 100 according to an embodiment of the present invention.

[0031] Referring to FIG. 2, a susceptor according to an embodiment of the present invention includes a laminated structure of an insulating plate 110, a heat insulating member 130, and a base member 120.

[0032] In the present invention, the insulating plate 110 is preferably circular, but may be designed in other shapes such as oval or square depending on the circumstances.

[0033] In the present invention, the insulating plate 110 includes one or more electrode layers therein. For example, the electrode layers may include a chuck electrode layer 114A, a heater electrode layer 114B, and an RF electrode layer 114C. However, it is of course possible to include only some of these electrode layers. Although each electrode layer is illustrated as being formed of a single layer, it is of course possible for each electrode layer to be formed of two or more layers, or for two or more electrode functions to be integrated into one electrode layer. Furthermore, an RF voltage may be applied to the base instead of the RF electrode layer 114C.

[0034] In the present invention, the insulating plate 110 may include a dielectric material, for example, at least one material selected from the group consisting of alumina (Al2O3), aluminum nitride (AlN), silicon carbide (SiC), silicon nitride (Si3N4), silicon oxide (SiO2), barium oxide (BaO), zinc oxide (ZnO), cobalt oxide (CoO), tin oxide (SnO2), zirconium oxide (ZrO2), yttria (Y2O3), and yttrium aluminates such as YAG, YAM, and YAP.

[0035] Preferably, in the present invention, the insulating plate 110 may be made of AlN. Insulating plates made of AlN generally have very high thermal conductivity, making them difficult to apply when a substrate needs to be divided into multiple heating zones and temperature controlled independently. In the present invention, AlN, which has low thermal conductivity, can be used as the material for the insulating plate 110.

[0036] In the present invention, low thermal conductivity AlN plates can be achieved by controlling the amount of sintering aids added. Oxygen dissolved in the AlN lattice reduces the thermal conductivity of AlN. Therefore, by limiting the content of alkaline earth metals such as Ca and Mg, rare earth metals such as yttrium (Y), and transition metals such as Ti, which are known as sintering aids, phonon scattering elements such as oxygen and vacancies can be retained in the lattice, resulting in the production of AlN sintered bodies with low thermal conductivity. For example, the shaft may be an AlN sintered body containing 2 wt% or less yttria as a sintering aid, and the thermal conductivity may be controlled by the content of sintering aids such as yttria.

[0037] More preferably, the AlN plate of the present invention may contain Mg and Ti as metal elements. Adding MgO as a sintering aid can decrease the thermal conductivity of the AlN plate. This may be due to the low thermal conductivity of grain boundary phases, such as spinel, that precipitate when MgO is added. Furthermore, TiO2 added as a sintering aid bonds with aluminum vacancies within the AlN lattice, thereby retaining the aluminum vacancies within the AlN lattice. This may decrease the thermal conductivity of AlN. The addition of MgO and TiO2 as sintering aids must be above the minimum limit required to exhibit an effective effect. Since increasing the amount can lead to saturation, an appropriate amount must be added. In the present invention, the Mg content in the sintered plate may be 0.1 wt% or more, 0.5 wt% or more, or 1.0 wt% or more, calculated as MgO, and 3.0 wt% or less, 2.5 wt% or less, 2.4 wt% or less, 2.3 wt% or less, 2.2 wt% or less, 2.1 wt% or less, or 2.0 wt% or less. The Ti content in the sintered plate 110 may be 0.05 wt% or more, 0.1 wt% or more, 0.15 wt% or more, or 0.2 wt% or more, calculated as TiO. The Ti content in the sintered plate may be 0.5 wt% or less, 0.4 wt% or less, 0.3 wt% or less, or 0.25 wt% or less.

[0038] In the present invention, the AlN plate 110 may have a thermal conductivity of 80 W / mK or less, 70 W / mK or less, 60 W / mK or less, or 50 W / mK or less at a temperature of 300° C. For example, the AlN plate preferably has a thermal conductivity of 40 to 60 W / mK at a temperature of 300° C.

[0039] In the present invention, the heater electrode layer 114B may be a multi-zone heater divided into multiple regions. For example, the heater electrode layer 114B may be a two-zone heater including two concentric heaters, such as an inner heater layer and an outer heater layer, or a multi-zone heater consisting of multiple concentric heater layers. Alternatively, the heater electrode layer 114B may include a fan-shaped multi-zone heater divided into multiple heating zones in a radial pattern.

[0040] The present invention uses a plate made of AlN material with a relatively low thermal conductivity, so that even when multiple heaters are used as described above, it is possible to realize a heater that shows different temperatures in separate regions.

[0041] Although the insulating plate 110 has been described as being formed as a single body, it is needless to say that the insulating plate 110 may have a laminated structure made up of two or more insulating layers (dielectric layers).

[0042] In the present invention, the electrode layers 114A, 114B, and 114C may be made of a conductive metal material and may be connected to connectors 140A, 140B, and 140C, respectively, to receive external power. For example, the electrode layers 114A, 114B, and 114C may be made of at least one of silver (Ag), gold (Au), nickel (Ni), tungsten (W), molybdenum (Mo), and titanium (Ti), such as tungsten (W). In the present invention, the electrode layers 114A, 114B, and 114C may be formed by a screen printing process or may be embodied as a metal processed product such as a foil, coil, or mesh.

[0043] In the present invention, the base member 120 may be a multi-layer structure made up of a plurality of metal layers, which may be bonded together by a brazing process, a welding process, a bonding process, or the like.

[0044] In the present invention, the base member 120 may be made of aluminum, an aluminum alloy, or a metal matrix composite (MMC). The MMC may be, for example, a composite of Al and SiC, with 20 to 70 wt% of SiC added. Using an MMC as the base member, as in the present invention, can reduce the difference in thermal expansion coefficient between the base member and the insulating member, thereby minimizing thermal deformation during the process.

[0045] In the present invention, a ceramic coating layer 126 may be applied to the surface of the base member 120 to improve heat insulating properties and reduce thermal conductivity. For example, Al2O3, Y2O3, or a compound thereof may be formed on the surface of the base material by atmospheric plasma spray coating.

[0046] A heat insulating member 130 is interposed between the insulating plate 110 and the base member 120 .

[0047] The heat insulating member 130 suppresses heat exchange between the insulating plate 110 and the base 120. Preferably, the heat insulating member is made of a material with low thermal conductivity and thermal expansion coefficient. In the present invention, the heat insulating member 130 may be a solid rigid plate. In the present invention, the heat insulating member 130 may have a thickness of preferably 5 to 20 mm.

[0048] In the present invention, the heat insulating member 130 preferably has a thermal conductivity of 20 W / mK or less, 15 W / mK or less, 10 W / mK or less, or 5 W / mK or less. Also, the heat insulating member preferably has a thermal expansion coefficient of 15 μm / mK or less, 10 μm / mK or less, or 5 μm / mK or less.

[0049] For example, the heat insulating member may be made of one material selected from the group consisting of Kovar, Titanium, Hastelloy, and Quartz. Preferably, the heat insulating member may be made of Quartz.

[0050] The physical properties of the aforementioned insulating materials are shown in Table 1 below.

[0051] [Table 1]

[0052] In the present invention, the susceptor includes a cooling mechanism for cooling the substrate by inflow of a cooling gas such as He, which may be implemented by a cooling gas flow path that connects the plate, the heat insulating member, and the base member.

[0053] In the present invention, the base member 120 includes a first cooling gas passage 122 through which cooling gas flows in from the outside. The first cooling gas passage 122 communicates with the gas holes 112 of the insulating plate through a second cooling gas passage 132 of a heat insulating member stacked on the base member 120, and the cooling gas is ejected toward the substrate.

[0054] In the present invention, the susceptor includes a pair of O-rings 132A at both ends of the second cooling gas passage 132 on the upper and lower surfaces of the heat insulating member to seal the flow of cooling gas through the cooling gas passage. In the present invention, the O-rings 132A may be made of a material that is heat-resistant at high temperatures of 300°C or higher. For example, an O-ring made of a perfluorinated material with a high fluorine content, such as FFKM, which has high thermal resistance, may be used. This allows stable airtightness to be maintained even during high-temperature processes at 300°C or higher.

[0055] In the present invention, the laminated structure including the base member 120, the heat insulating member 130, and the insulating plate 110 is fastened by a fastening device 150. The fastening device 150 may be based on a conventional screw fastening structure, such as a bolt that passes through the base member 120, the heat insulating member 130, and the insulating plate 110 in the vertical direction, and a nut that is fastened to the bolt.

[0056] The susceptor of the present invention includes an outer O-ring 132B for supporting the laminated structure of the base member, the insulating member, and the plate. The outer O-ring 132B may follow the contour shape of the insulating plate, for example, the O-ring may be a circular ring. As described above, the outer O-ring is also preferably made of a material that is heat-resistant at temperatures above 300°C, such as an O-ring made of FFKM.

[0057] Although the present invention has been described above using exemplary embodiments and drawings, these are provided merely to facilitate a more comprehensive understanding of the present invention, and the present invention is not limited to the above embodiments, and those skilled in the art will understand that various modifications and variations are possible within the scope of the essential characteristics of the present invention. Therefore, the concept of the present invention should not be limited to the described embodiments, and should be interpreted as including within the scope of the claims, as well as any technical concept equivalent to or modified from the scope of the claims. [Explanation of symbols]

[0058] 110 Insulation plate 114A,114B,114C electrode layer 120 Base material 122 first cooling gas flow path 24,124 Refrigerant flow path 130 Heat insulating materials 132 second cooling gas flow path 132A O-ring 132B Outer O-ring 140A, 140B, 140C connectors 150 Fastening device

Claims

1. a base member having a first cooling gas flow path for allowing a cooling gas to flow therethrough; a heat insulating member having a second cooling gas flow path communicating with the first cooling gas flow path and having a thermal conductivity of 20 W / mK or less and laminated on the base member; an insulating plate stacked on the heat insulating member and having a plurality of gas holes communicating with the second cooling gas flow path to eject a cooling gas for cooling the substrate; a laminated structure of the base member, the heat insulating member, and the insulating plate; a first surface of the heat insulating member in contact with the base member and a second surface of the heat insulating member in contact with the insulating plate each include an outer periphery O-ring disposed along an outer periphery of the laminated structure; Susceptor.

2. The susceptor according to claim 1 , wherein the heat insulating member is made of quartz.

3. 2. The susceptor according to claim 1, wherein the heat insulating member comprises a material selected from the group consisting of Kovar, Ti, and Hastelloy.

4. The susceptor according to claim 1 , wherein the heat insulating member is a rigid plate.

5. The susceptor of claim 1 , wherein the base member is a metal matrix composite (MMC) or aluminum.

6. The susceptor according to claim 1 , wherein the insulating plate has a thermal conductivity of 50 W / mK or less at 300° C.

7. The susceptor according to claim 6, wherein the insulating plate is made of aluminum nitride.

8. The aluminum nitride material further contains Mg and Ti, The Mg content in the aluminum nitride material is 1 to 3 wt % in terms of MgO, and the Ti content is TiO ２ The susceptor according to claim 7, characterized in that the content is 0.1 to 0.5 wt % in terms of the total weight of the carbon nanotube.

9. The susceptor according to claim 1 , wherein the heat insulating member has a thermal conductivity of 20 W / mK or less at 300° C.

10. The susceptor according to claim 1 , wherein the heat insulating member has a thermal expansion coefficient of 10 μm / mK or less at 300° C.

11. a plurality of fastening devices that penetrate the laminated structure vertically and join the laminated structure at an outer casing of the laminated structure; The susceptor according to claim 1 , wherein the outer O-ring is disposed inside the plurality of fastening devices.

12. the heat insulating member has a first surface in contact with the base member and a second surface in contact with the insulating plate; The susceptor according to claim 1 , wherein the first surface and the second surface of the heat insulating member are each provided with an O-ring for sealing the second cooling gas flow path.

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