Susceptor for high temperature semiconductor process

Abstract

The present invention provides a base comprising: a base member having a first cooling gas flow path for allowing cooling gas to flow in; a heat insulation member having a second cooling gas flow path communicating with the first cooling gas flow path and being stacked on the base member and having a thermal conductivity of less than 20 W / mK; and an insulating plate being stacked on the heat insulation member and having a plurality of pores, the plurality of pores communicating with the second cooling gas flow path and having the ability to eject cooling gas for cooling a substrate.

Description

High-temperature semiconductor process susceptor The present invention relates to a susceptor, and more particularly, to a susceptor for supporting a substrate in a high-temperature semiconductor process. Semiconductor devices or display devices are manufactured by stacking and patterning multiple thin film layers, including dielectric and metal layers, on glass substrates, flexible substrates, or semiconductor wafer substrates through semiconductor processing methods such as chemical vapor deposition (CVD), physical vapor deposition (PVD), ion implantation, and etching. Chambers used to perform these semiconductor processes utilize susceptors to support various substrates, such as glass, flexible, and semiconductor wafer substrates. A representative example is an electrostatic chuck (ESC), which utilizes electrostatic force to secure the substrate. FIG. 1 is a diagram schematically showing an example of a conventional electrostatic chuck. 1 , the electrostatic chuck includes a base 20 and an insulating plate 10 located on the base 20 . The insulating plate 10 may be generally made of a ceramic material such as alumina. Electrodes 14 such as DC electrodes, heater electrodes and / or RF electrodes may be embedded in the insulating plate 10. To uniformly cool the substrate on insulating plate 10, a cooling structure is provided on base 20 and insulating plate 10 bonded to base 20. Cooling gas flowing through cooling gas flow paths 22 provided on base 20 communicates with air holes 12 in insulating plate 10, cooling the substrate. In the conventional electrostatic chuck structure described above, base 20 and insulating plate 10 are bonded together by adhesive layer 30. The manufacturing process of semiconductor devices using the electrostatic chuck described above is gradually developing toward increasing the aspect ratio of the device by stacking fine patterns at an ultra-high level. In order to create high-aspect-ratio patterns in semiconductor manufacturing, the plasma voltage and process time increase, especially for NAND processes with more than 200 layers. Therefore, materials with excellent plasma resistance, such as boron-doped amorphous carbon layers and silicon oxynitride, are being selected as hard mask materials for next-generation processes. This has led to an increasing difficulty in etching hard mask layers. To improve the reactivity and selectivity required in the etching process for etching the hard mask layer, electrostatic chucks must operate at temperatures above 300°C. However, because conventional electrostatic chucks use organic materials such as silicone as an adhesive between the ceramic and metal bodies, they degrade and decompose at high temperatures, resulting in an inability to maintain adhesion at process temperatures. In addition, conventional electrostatic chucks have a high coefficient of thermal expansion between the ceramic and metal bases, which can cause significant stress on the adhesive layer between the base and the plate during high-temperature processing. Furthermore, to increase the temperature of the electrostatic chuck to accommodate high-temperature processes, a material with high thermal conductivity, such as AlN, is preferred. However, AlN has a high thermal conductivity of 180 kW / m·K, making it difficult to control the temperature by dividing the heating area within the electrostatic chuck. [Prior Art Documents] [Patent Documents] Patent Document 0001: KR2288530B. Patent Document 0002: JP7052847B. [Problems to be solved by the invention] In order to solve the above-mentioned problems of the prior art, an object of the present invention is to provide a base structure that can suppress the degradation of the joint between the insulating plate and the base during a high-temperature process. In addition, an object of the present invention is to provide a base, which is based on a non-bonded structure of an insulating plate and a base, so as to be suitable for application in high-temperature processes. Another object of the present invention is to provide a susceptor having a structure that allows independent temperature control of a plurality of heating areas while using AlN material having high thermal conductivity as a ceramic material. [Methods used to solve the problem] In order to solve the above technical problems, the present invention provides a base, comprising: a base member, having a first cooling gas flow path for allowing cooling gas to flow in; a heat-insulating member, having a second cooling gas flow path connected to the first cooling gas flow path, the heat-insulating member being stacked on the base member and having a thermal conductivity of less than 20 W / mK; and an insulating plate, stacked on the heat-insulating member and having a plurality of air holes, the plurality of air holes being connected to the second cooling gas flow path and ejecting cooling gas for cooling the substrate. In the present invention, the heat insulating member may be made of quartz, or any one material selected from the group consisting of Kovar, Ti, and Hastelloy. In the present invention, the heat insulating member may be a rigid plate. In addition, in the present invention, the base member may be a metal matrix composite (MMC) or aluminum. In the present invention, the thermal conductivity of the insulating plate at 300°C is preferably 50W / mK or less. In this case, the insulating plate can be made of aluminum nitride and can also contain Mg and Ti. In this case, the content of Mg in the aluminum nitride material is preferably 1-3wt% in terms of MgO and 1-3wt% in terms of TiO. 2, the Ti content is preferably 0.1-0.5wt%. In the present invention, the thermal conductivity of the thermal insulation member at 300° C. is preferably 20 W / mK or less. In the present invention, the thermal expansion coefficient of the thermal insulation member at 300° C. is preferably 10 μm / mK or less. In the present invention, outer O-rings arranged along an outer periphery of the stacked structure may be provided on each of a first surface of the heat insulating member contacting the base member and a second surface of the heat insulating member contacting the insulating plate. In addition, in the present invention, a plurality of fastening units penetrating the stacked structure vertically and connected to the stacked structure are provided on the outer shell of the stacked structure, and the outer shell O-ring can be arranged inside the plurality of fastening units. In the present invention, the base has air holes of the insulating plate, the air holes are used to cool the substrate on the insulating plate, and the air holes can be communicated with the cooling gas communication holes of the base member. In the present invention, the thermal insulation member has a first surface in contact with the base member and a second surface in contact with the insulating plate, and O-rings for sealing the second cooling gas flow path may be provided on the first and second surfaces of the thermal insulation member, respectively. [Effects of the Invention] The present invention provides a susceptor structure that can suppress degradation of the joint between the ceramic and the base during high-temperature processes. Furthermore, the present invention provides a susceptor structure that utilizes AlN, a highly thermally conductive material, as the ceramic material while allowing for independent temperature control of multiple heating zones. Unless otherwise defined, all technical and scientific terms used in this specification have the same meanings as those commonly understood by those skilled in the art to which the present invention pertains. The nomenclature generally used in this specification is a method widely known and commonly used in the art. Throughout this specification, when a section "includes" a certain component, unless otherwise specified, it implies that other components may also be included, not that other components are excluded. Furthermore, in this specification, the term "material A" refers not only to a composition consisting solely of substance A, but also to a composition containing substance A as the primary component (comprising 50% or more by weight) but containing other substances other than substance A, or a composite of substance A and other substances. Furthermore, in the present invention, "stacked" can refer to a state in which two adjacent layers are in direct contact, or a state in which another layer intervenes but is not in contact. FIG. 2 is a cross-sectional view illustrating the structure of an electrostatic chuck 100 according to an embodiment of the present invention. 2 , the base according to an embodiment of the present invention includes a stacked structure of an insulating plate 110 , a heat insulating member 130 , and a base member 120 . In the present invention, the insulating plate 110 is preferably circular in shape, but may also be designed to be other shapes such as elliptical or rectangular depending on the situation. In the present invention, the insulating plate 110 includes one or more electrode layers. By way of example, these electrode layers may include a chuck electrode layer 114A, a heater electrode layer 114B, and an RF electrode layer 114C, but it is also possible to include only a portion of these electrode layers. Furthermore, while each electrode layer is shown as a single layer, it is also possible to include two or more layers. Furthermore, it is also possible to integrate the functions of two or more electrodes into a single electrode layer. Furthermore, an RF voltage may be applied to the base instead of the RF electrode layer 114C. In the present invention, the insulating plate 110 may include a dielectric material, for example, aluminum oxide (Al 2O 3) Aluminum nitride (AlN), silicon carbide (SiC), silicon nitride (Si 3N 4) Silicon oxide (SiO 2), barium oxide (BaO), zinc oxide (ZnO), cobalt oxide (CoO), tin oxide (SnO 2) Zirconium oxide (ZrO 2) Yttrium oxide (Y 2O 3) and at least one substance selected from the group consisting of yttrium aluminates such as YAG, YAM, and YAP. Preferably, in the present invention, the insulating plate 110 can be made of AlN. AlN insulating plates typically exhibit very high thermal conductivity, making them difficult to use in situations where the substrate needs to be divided into multiple heating zones for independent temperature control. However, the present invention allows the insulating plate 110 to be made of AlN, which has low thermal conductivity. In the present invention, low thermal conductivity AlN plates can be achieved by controlling the amount of sintering aid added. Oxygen dissolved within the AlN lattice reduces AlN's thermal conductivity. Therefore, by suppressing the content of sintering aids—alkaline earth metals such as Ca and Mg, rare earth metals such as yttrium (Y), and transition metals such as Ti—phonon scattering elements such as oxygen and vacancies within the lattice can be maintained, allowing the production of AlN sintered bodies with low thermal conductivity. As an example, the shaft can be an AlN sintered body containing 2 wt% or less of yttrium oxide as a sintering aid, and the thermal conductivity can be controlled by adjusting the content of sintering aids such as yttrium oxide. More preferably, the AlN plate of the present invention may contain Mg and Ti as metal elements. By adding MgO as a sintering aid, the thermal conductivity of the AlN plate can be reduced. This is probably due to the low thermal conductivity of the grain boundary phases such as spinel precipitated after the addition of MgO. In addition, TiO added as a sintering aid can reduce the thermal conductivity of the AlN plate. 2 combines with aluminum vacancies inside the AlN lattice, making it possible to keep the aluminum vacancies within the AlN lattice. Therefore, the thermal conductivity of AlN can be reduced. MgO and TiO as sintering aids 2 It is necessary to add more than the minimum level that shows an effective effect, and as the amount of addition increases, it will reach a saturated state, so it is necessary to add an appropriate amount. In addition, in the present invention, in the plate sintered body, based on MgO conversion, the Mg content may include 0.1wt% or more, 0.5wt% or more, or 1.0wt% or more, and may include 3.0wt% or less, 2.5wt% or less, 2.4wt% or less, 2.3wt% or less, 2.2wt% or less, 2.1wt% or less, or 2.0wt% or less. In addition, in the sintered body of the plate 110, the content of Mg in the form of TiO 2 converted to the base, the Ti content may be 0.05 wt% or more, 0.1 wt% or more, 0.15 wt% or more, or 0.2 wt% or more. In addition, the Ti content in the sintered body may be 0.5 wt% or less, 0.4 wt% or less, 0.3 wt% or less, or 0.25 wt% or less. 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 40-60 W / mK at a temperature of 300° C. In the present invention, the heater electrode layer 114B may be a multi-zone heater divided into multiple zones. For example, the heater electrode layer 114B may be a dual-zone heater comprising two concentric heaters, such as an inner heater layer and an outer heater layer, or a multi-zone heater comprising multiple concentric heater layers. Alternatively, the heater electrode layer 114B may comprise a sector-shaped multi-zone heater radially divided into multiple heating zones. In the present invention, the use of a plate made of an AlN material having relatively low thermal conductivity enables the realization of heaters capable of exhibiting different temperatures for divided areas even when multiple heaters are used as described above. Although the insulating plate 110 is described as forming a single body above, it is a matter of course that the insulating plate 110 may be formed of a stacked structure consisting of two or more insulating layers (dielectric layers). In the present invention, the electrode layers 114A, 114B, and 114C can be made of a conductive metal material and can be connected to the connectors 140A, 140B, and 140C, respectively, to receive external power. For example, the electrode layers 114A, 114B, and 114C can be formed from at least one of silver (Ag), gold (Au), nickel (Ni), tungsten (W), molybdenum (Mo), and titanium (Ti), and can be formed from tungsten (W). In the present invention, the electrode layers 114A, 114B, and 114C can be formed using a screen printing process or can be implemented as a processed metal object such as foil, coil, or mesh. In the present invention, the base member 120 may be formed of a multi-layer structure including a plurality of metal layers, and the metal layers may be bonded together by a brazing process, a welding process, or a bonding process. In the present invention, the base member 120 can be made of aluminum, an aluminum alloy, or a metal matrix composite (MMC). In the case of MMC, for example, a composite of Al and SiC can be used, with SiC added at a ratio of 20-70 wt%. When MMC is used as the base member, as in the present invention, the difference in thermal expansion coefficient between the base member and the thermal insulation member can be reduced, thereby minimizing thermal deformation associated with the manufacturing process. In the present invention, a ceramic coating 126 may be added to the surface of the base member 120 to improve the thermal insulation properties and reduce the thermal conductivity. 2O 3. Y 2O 3 or their compounds can be formed on the surface of the base base material by atmospheric pressure plasma thermal spraying. A heat insulating member 130 is interposed between the insulating plate 110 and the base member 120 . The thermal insulation member 130 inhibits heat exchange between the insulating plate 110 and the base 120. Preferably, the thermal insulation member 130 is made of a material with low thermal conductivity and thermal expansion coefficient. In the present invention, the thermal insulation member 130 may be a solid rigid plate. In the present invention, the thermal insulation member 130 preferably has a thickness of 5 to 20 mm. In the present invention, the thermal insulation 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. Furthermore, the thermal insulation member 130 preferably has a thermal expansion coefficient of 15 μm / mK or less, 10 μm / mK or less, or 5 μm / mK or less. For example, the thermal insulation member 130 is preferably made of a material selected from the group consisting of Kovar, Titanium, Hastelloy, and Quartz. Preferably, the thermal insulation member 130 is made of quartz. The physical properties of the above-mentioned thermal insulation members are shown in Table 1 below. [Table 1] In the present invention, the susceptor has a cooling mechanism for cooling the substrate by introducing a cooling gas such as He. The cooling mechanism can be realized by a cooling gas flow path communicating the plate, the heat insulating member, and the base member. In the present invention, the base member 120 has a first cooling gas flow path 122 for flowing cooling gas from the outside. The first cooling gas flow path 122 is connected to the air holes 112 of the insulating plate 110 through the second cooling gas flow path 132 of the heat insulating member 130 stacked on the base member 120, so that the cooling gas is sprayed toward the substrate side. In the present invention, to seal the flow of cooling gas through the cooling gas flow path, a pair of O-rings 132A may be provided at both ends of the second cooling gas flow path 132 on the upper and lower surfaces of the base's thermal insulation member 130. In the present invention, the O-rings 132A may be made of a material that is heat-resistant at temperatures above 300°C. For example, an O-ring made of a perfluorocarbon material with a high fluorine content, such as highly heat-resistant FFKM (perfluoroelastomer), may be used. This ensures stable airtightness even during high-temperature processes exceeding 300°C. In the present invention, the stacked structure including the base member 120, the thermal insulation member 130, and the insulating plate 110 is connected by a fastening unit 150. The fastening unit 150 can be based on a common screw connection structure, for example, a bolt that passes through the base member 120, the thermal insulation member 130, and the insulating plate 110 from top to bottom, and a nut that can be connected to the bolt. The base of the present invention may include an outer O-ring 132B for supporting the stacked structure of the base member 120, the thermal insulation member 130, and the insulation plate 110. The outer O-ring 132B may follow the contour of the insulation plate 110 and, for example, may be a circular ring. As mentioned above, the outer O-ring 132B may also preferably be made of a material that is heat-resistant at temperatures above 300°C (e.g., FFKM). The present invention has been described above by means of exemplary embodiments and drawings, but this is only provided to facilitate understanding of the present invention as a whole, and the present invention is not limited to the embodiments. A person skilled in the art can make various modifications and changes without departing from the essential features of the present invention. Therefore, the spirit of the present invention should not be limited to the embodiments described and determined. In addition to the scope of the claims, all technical ideas that are equivalent to or equivalent to the scope of the claims should be interpreted as being included within the scope of the present invention. 14: Electrode 20: Base 22: Cooling gas flow path 100: Electrostatic chuck 10, 110: Insulating plate 12, 112: Air hole 114A, 114B, 114C: Electrode layer 120: Base member 122: First cooling gas flow path 24, 124: Refrigerant channel 126: Ceramic coating 130: Thermal insulation member 132: Second cooling gas flow path 132A: O-ring 132B: Outer O-ring 140A, 140B, 140C: Connector 150: Fastening unit FIG. 1 is a diagram schematically showing a conventional base structure. FIG. 2 is a diagram schematically illustrating a base structure according to an embodiment of the present invention. 100: Electrostatic chuck 110:Insulation board 112: Stoma 114A, 114B, 114C: electrode layer 120: Base component 122: First cooling gas flow path 124: Refrigerant channel 126: Ceramic coating 130: Thermal insulation components 132: Second cooling gas flow path 132A: O-ring 132B: Outer O-ring 140A, 140B, 140C: Connectors 150: Fastening unit

Claims

1. A base, characterized in that it comprises: The base component has a first cooling gas flow path for allowing cooling gas to flow in; A heat insulation member has a second cooling gas flow path communicating with the first cooling gas flow path. The heat insulation member is stacked on the base member and has a thermal conductivity of less than 20 W / mK. An insulating plate is stacked on the heat insulation member and has a plurality of pores. The plurality of pores communicate with the second cooling gas flow path and spray cooling gas for cooling the substrate. The base has a stacked structure including the base member, the heat insulation member, and the insulating plate. On the first surface of the heat insulation member in contact with the base member and the second surface of the heat insulation member in contact with the insulating plate, an outer contour O-ring is respectively provided along the outer contour of the stacked structure.

2. The base as described in claim 1, wherein, The heat insulation component is made of quartz.

3. The base as described in claim 1, wherein, The thermal insulation component comprises a material selected from the group consisting of Kovar, Ti and Hastelloy.

4. The base as described in claim 1, wherein, The heat insulation component is a rigid plate.

5. The base as described in claim 1, wherein, The base component is a metal-based composite or aluminum.

6. The base as described in claim 1, wherein, The thermal conductivity of the insulating board at 300℃ is below 50W / mK.

7. The base as described in claim 6, wherein, The insulating board is made of aluminum nitride.

8. The base as described in claim 7, wherein, The aluminum nitride material contains Mg and Ti. In the aluminum nitride material, the content of Mg, calculated as MgO, is 1~3wt%, and the content of Ti, calculated as TiO2, is 0.1~0.5wt%.

9. The base as described in claim 1, wherein, The thermal insulation component has a thermal conductivity of less than 20 W / mK at 300°C.

10. The base as described in claim 1, wherein, The thermal expansion coefficient of the insulation component at 300℃ is less than 10μm / mK.

11. The base as described in claim 1, wherein, Multiple fastening units are provided on the outer contour of the stacked structure. The multiple fastening units penetrate the stacked structure vertically and are combined with the stacked structure. The outer contour O-ring is disposed on the inner side of the multiple fastening units.

12. The base as described in claim 1, wherein, The heat insulation component has a first surface that contacts the base component and a second surface that contacts the insulating plate. On the first surface and the second surface of the heat insulation component, O-rings for sealing the second cooling gas flow path are respectively provided.

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