Susceptor

Abstract

The present invention provides a susceptor comprising: a base member; and a dielectric plate adhered to the base member by means of an adhesive layer, wherein the base member is a metal-ceramic composite, and a thermal expansion coefficient ratio of the metal-ceramic composite to a ceramic material of the dielectric plate is less than 1.5 in the entire temperature range of -100℃ to 200℃.

Description

susceptor

[0001] The present invention relates to a susceptor, and more particularly, to a susceptor for supporting a wafer in a semiconductor manufacturing process and a method for manufacturing the same.

[0002] Semiconductor devices or display devices are manufactured by laminating 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) processes, physical vapor deposition (PVD) processes, ion implantation processes, and etch processes. In chambers for performing these semiconductor processes, susceptors are used to support various substrates such as glass substrates, flexible substrates, and semiconductor wafer substrates. A representative example is an electrostatic chuck (ESC) that uses electrostatic force to fix the substrate.

[0003] Susceptors like this are typically used to support substrates at room or high temperatures. However, with the recent miniaturization and increased integration of semiconductor devices, the difficulty of film deposition and / or dry etching processes has increased sharply. Furthermore, next-generation etching processes are demanding ever-fine line widths and higher etch selectivities.

[0004] Two approaches are being used to achieve this. The first is to perform anisotropic etching by lowering the process pressure and increasing the ESC RF power. However, in this case, the process temperature increases to 150°C due to the high RF power used.

[0005] Second, the need to perform film deposition or etching processes by lowering the process temperature to below -100°C is emerging. Lowering the chamber temperature minimizes gas movement, enabling etching without polymers.

[0006] For this reason, next-generation etching processes require continuous high-temperature and cryogenic processes, and there is a need for an electrostatic chuck that can be applied to such thermal cycle conditions.

[0007] Conventional electrostatic chucks utilize a structure consisting of an aluminum body with a high coefficient of thermal expansion and a dielectric plate with a relatively low coefficient of thermal expansion, bonded together with silicone adhesive. However, changes in process temperature can cause stress and deformation due to thermal expansion, potentially leading to degradation of the silicone adhesive or a decrease in adhesive strength and resilience.

[0008] Additionally, when the process temperature changes over a wide temperature range, including cryogenic temperatures, there is a risk that the adhesive may deteriorate, harden, and break due to stress and deformation caused by heat shrinkage.

[0009] In addition, conventional susceptors do not take into account simultaneous use at such extremely low and high temperatures, and there is a severe lack of consideration for securing reliable adhesion properties between the dielectric plate and the base even under such extreme conditions.

[0010] In order to solve the problems of the above-mentioned prior art, the present invention aims to provide a susceptor having a structure that minimizes thermal stress occurring between a base member and a dielectric plate in a wide temperature range in which cryogenic processes and high-temperature processes are performed.

[0011] In addition, the present invention aims to provide a susceptor that minimizes thermal stress in a wide temperature range in which cryogenic processes and high-temperature processes are performed by taking into account the difference in thermal expansion coefficient changes of metal and ceramic within a base member.

[0012] In addition, the present invention aims to provide a susceptor having an adhesive layer suitable for alleviating thermal stress occurring between a base member and a dielectric plate in a wide temperature range in which cryogenic processes and high-temperature processes are performed.

[0013] In order to achieve the above technical task, the present invention provides a susceptor including a base member and a dielectric plate bonded to the base member by an adhesive layer, wherein the base member is a metal-ceramic composite, and a ratio of the coefficient of thermal expansion of the metal-ceramic composite to the ceramic material of the dielectric plate is less than 1.5 in the entire temperature range of -100°C to 200°C.

[0014] In the present invention, the thermal expansion coefficient ratio of the metal-ceramic composite to the plate may be 1.2 or less over the entire temperature range of -100°C to 200°C.

[0015] Additionally, over the entire temperature range of -100°C to 200°C, the coefficient of thermal expansion ratio of the metal-ceramic composite to the plate may be 0.6 or greater.

[0016] In the present invention, the adhesive layer may include silicone resin.

[0017] In the present invention, the adhesive layer may have an elastic modulus of 1 MPa to 3 MPa.

[0018] In the present invention, the adhesive layer may have an elongation at -70°C of 200 to 400% after being exposed to a thermal cycle of 150°C to -70°C 100 times. In addition, in the present invention, the adhesive layer may have an elongation at room temperature of 100 to 200% after being exposed to a thermal cycle of 150°C to -70°C 100 times.

[0019] In the present invention, the silicone resin may have inorganic particles dispersed therein, and the silicone resin may include phenyl silicone.

[0020] According to the present invention, it is possible to provide a susceptor having a structure that minimizes thermal stress occurring between a base member and a dielectric plate in a wide temperature range in which cryogenic processes and high-temperature processes are performed.

[0021] In addition, according to the present invention, it is possible to provide a susceptor that minimizes thermal stress in a wide temperature range in which cryogenic processes and high-temperature processes are performed, despite the difference in thermal expansion coefficient changes of metal and ceramic within the base member.

[0022] In addition, according to the present invention, it is possible to provide a susceptor having an adhesive layer suitable for alleviating thermal stress occurring between a base member and a dielectric plate in a wide temperature range in which cryogenic processes and high-temperature processes are performed.

[0023] FIG. 1 is a schematic drawing showing a cross-section of a susceptor according to one embodiment of the present invention.

[0024] Figure 2 shows the chemical formula of an adhesive for forming an adhesive layer according to one embodiment of the present invention.

[0025] Figure 3 is a photograph taken during the shear strength measurement process.

[0026] 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. In general, the nomenclature used herein is well known and commonly used in the art.

[0027] Throughout this specification, when a part is said to "include" a certain component, this does not mean that other components may be included, but rather that other components may be excluded, unless otherwise specifically stated. Furthermore, the expression "material A" in this specification is used to mean not only a material composed solely of material A, but also a material that has material A as the main component (a component accounting for 50% or more by weight) but is mixed with other materials other than material A, or a composite material of material A and other materials.

[0028] FIG. 1 is a cross-sectional view for explaining the structure of an electrostatic chuck (100) according to one embodiment of the present invention.

[0029] Referring to Fig. 1, an electrostatic chuck (100) according to one embodiment of the present invention includes a base member (120) at the bottom and a dielectric plate (140) at the top. The electrostatic chuck (100) is preferably of a circular type, but may be designed in other shapes such as an oval or a square shape depending on the case.

[0030] As illustrated, in the present invention, the dielectric plate (140) may have an electrode layer (144). For example, the dielectric plate may have a laminated structure of an insulating layer (142), an electrode layer (144) on the insulating layer (142), and a dielectric layer (146) on the electrode layer (144), but the present invention is not limited thereto.

[0031] In the present invention, the insulating layer (142) may be formed of a ceramic material. In one embodiment, the insulating layer (142) may be formed of 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 aluminate such as YAG, YAM, and YAP.

[0032] In the present invention, the electrode layer (144) is made of a conductive metal material and is connected to a connector (180) so that power is supplied from outside the electrostatic chuck. As an example, the electrode layer (144) may be formed of at least one metal selected from the group consisting of silver (Ag), gold (Au), nickel (Ni), tungsten (W), molybdenum (Mo), titanium (Ti), platinum (Pt), and palladium (Pd) or an alloy thereof, and may be formed of tungsten (W) as an example. In the present invention, the electrode layer (144) may be formed using a thermal spray coating process or a screen printing process.

[0033] The above electrode layer (144) can control chucking by generating an electrostatic force by receiving a bias when loading a substrate (not shown) placed on top of the dielectric layer (146). When unloading the substrate (not shown), dechucking can be achieved by applying an opposite bias to the electrode layer (144) to cause discharge.

[0034] In the present invention, the dielectric layer (146) may be formed of a ceramic material. In one embodiment, the dielectric layer (146) may be formed of the same material as that mentioned in the above-described insulating layer (142). For example, the dielectric layer (146) may be formed of one material selected from among 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), Y2O3, and yttrium aluminate materials such as YAG, YAM, and YAP.

[0035] In the present invention, the dielectric plate (140) including the insulating layer (142) and the dielectric layer (146) may be formed by a laminated structure of sheets of ceramic material. For example, it may be formed by laminating a plurality of ceramic green sheets forming an electrode layer (144) and then sintering them, or by laminating a plurality of ceramic sintered sheets forming an electrode layer (144) and then bonding them by pressure sintering such as hot pressing. Alternatively, it goes without saying that part or all of the insulating layer (142) and / or the dielectric layer (146) may be formed by coating a ceramic material by plasma spraying, aerosol deposition, or the like.

[0036] Although the dielectric plate of the present invention has been described as having a laminated structure in which an insulating layer and a dielectric layer are laminated, the present invention is not limited thereto. The dielectric plate may be configured as a single body without a layer distinction, and in this case, the dielectric plate may be formed of, for example, one material selected from among 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), Y2O3, and yttrium aluminate materials such as YAG, YAM, and YAP.

[0037] In order to uniformly cool a substrate (e.g., a glass substrate, a flexible substrate, a semiconductor wafer substrate, etc.) on a dielectric plate (140) using an external cooling gas, a cooling gas passage (124) is formed on the base member (120) to provide a passage for the flow of base cooling gas. A plurality of gas holes (48) are formed on the surface of the dielectric plate (140) to communicate with the cooling gas passage (124) and to eject cooling gas onto the upper portion of the dielectric layer (146).

[0038] Although the drawing shows that the cooling gas passage (124) is vertically connected to the gas holes (48), this arrangement is exemplary and the present invention is not limited thereto. In addition, in the present invention, the cooling gas passage (124) is connected by penetrating the adhesive layer (160). At this time, it goes without saying that the cooling gas passage (124) can be connected to the gas holes (48) by penetrating the adhesive layer, particularly the spacer (162).

[0039] Meanwhile, the base member (120) is provided with a refrigerant passage (122) through which refrigerant for controlling the temperature of the base member (120) is circulated. The refrigerant passage (122) may be provided with an inlet for introducing refrigerant from the outside of the base member and an outlet for discharging the circulated refrigerant.

[0040] In the present invention, the base member (120) comprises a ceramic material. Preferably, the base member (120) may be a metal-ceramic composite. For example, in the present invention, the metal portion of the metal-ceramic composite may be an Al alloy with Al as the main component. For example, the metal portion may be Al6061 containing small amounts of Mg, Si, Cu, etc.

[0041] In the present invention, the ceramic portion of the metal-ceramic composite may be formed of one material selected from among silicon carbide (SiC), aluminum nitride (AlN), silicon nitride (Si3N4), silicon oxide (SiO2), barium oxide (BaO), zinc oxide (ZnO), cobalt oxide (CoO), tin oxide (SnO2), zirconium oxide (ZrO2), Y2O3, and yttrium aluminate materials such as YAG, YAM, and YAP. For example, in the present invention, the ceramic portion may be silicon carbide (SiC).

[0042] In the present invention, the ceramic portion of the metal-ceramic composite forms a continuous skeleton, and the metal portion fills the space between the skeletons.

[0043] For example, in the present invention, when the metal-ceramic composite is made of an Al-SiC material, it may include 20 to 85 wt% of Al and 15 to 80 wt% of SiC. Preferably, the SiC content may be 80 wt% or less, 75 wt% or less, 65 wt% or less, 60 wt% or less, 55 wt% or less, 50 wt% or less, 45 wt% or less, 40 wt% or less, 35 wt% or less, 30 wt% or less, or 25 wt% or less. In addition, in the present invention, the SiC content may be 20 wt% or more, 25 wt% or more, 30 wt% or more, 35 wt% or more, 40 wt% or more, 45 wt% or more, 50 wt% or more, 55 wt% or more, 60 wt% or more, 65 wt% or more, or 70 wt% or more.

[0044] The susceptor of the present invention has a coefficient of thermal expansion (CTE) of the ceramic material of the dielectric plate expressed by the following mathematical formula in the entire temperature range of -100°C to 200°C. p ) for the coefficient of thermal expansion (CTE) of the metal-ceramic composite c ) is preferably less than 1.5. Here, the ceramic material of the dielectric plate refers to the material of the ceramic part constituting the dielectric plate, and when the dielectric plate has the laminated structure of Fig. 1, it refers to the material of the insulating layer (142) in contact with the base member in the dielectric plate.

[0045] [Mathematical formula]

[0046] Coefficient of thermal expansion ratio = [CTE c / CTE p ]

[0047]

[0048] More preferably, in the present invention, the upper limit of the ratio of the thermal expansion coefficient in the entire temperature range of -100°C to 200°C may be 1.4 or less, 1.3 or less, 1.2 or less, or 1.15 or less. In addition, at this time, it is preferable that the ratio of the thermal expansion coefficient in the entire temperature range of -100°C to 200°C is 0.59 or more, 0.60 or more, 0.61 or more, or 0.62 or more.

[0049] Meanwhile, in the present invention, the thermal expansion coefficient ratio at -100°C may be 0.59 or more, 0.60 or more, 0.61 or more, or 0.62 or more. In addition, the thermal expansion coefficient ratio at 200°C may be 1.4 or less, 1.3 or less, 1.2 or less, or 1.15 or less.

[0050] The susceptor of the present invention has a CTE in the low temperature range among the entire temperature range of -100°C to 200°C. c is CTE p has a smaller value. In addition, the susceptor of the present invention has a CTE in the high temperature range. c is CTE p has a larger value, CTE c Wow CTE p The point where the values ​​are the same (i.e., the intersection) exists between the temperature range of -100 to 200°C. Preferably, the content of the metal portion and the ceramic portion of the base member is controlled so that the intersection is located within an appropriate temperature range.

[0051]

[0052] In the present invention, the above-mentioned intersection may be formed at 25°C or higher, 30°C or higher, 35°C or higher, 40°C or higher, 45°C or higher, 50°C or higher, or 60°C or higher, and may be formed at 100°C or lower, 90°C or lower, 80°C or lower, or 70°C or lower.

[0053] In the present invention, the dielectric plate (140) is bonded to the base member (120) by an adhesive layer.

[0054] As illustrated, an adhesive layer (160) is provided between the dielectric plate and the base member for bonding or joining the two. The adhesive layer (160) may include a plurality of spacers (162) for maintaining a gap between the dielectric plate and the base member. In addition, an adhesive (164) for bonding the dielectric plate and the base member is applied to an area of ​​the adhesive layer other than an area where the spacers (162) are formed.

[0055] In the present invention, at least one elastic polymer selected from the group consisting of silicone resin (or silicone rubber), butadiene, a hybrid polymer of styrene and acrylonitrile, butyl rubber, and fluoro rubber may be used as the adhesive layer.

[0056] In the present invention, the elastomer is preferably a silicone resin. The silicone resin may have a molecular structure in which at least one of a methyl group, an ethyl group, a propyl group, a butyl group, a phenyl group, and a hexyl group is bonded to a siloxane backbone. For example, silicone rubber containing a phenyl group in the axial chain is suitable for use at ultra-low temperatures below -50°C.

[0057] In the present invention, the elastic polymer may be an inorganic powder dispersed on an elastic polymer matrix. For example, in the present invention, the inorganic powder may be one selected from among iron oxides such as FeO, Fe2O3, or Fe3O4, 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), Y2O3, and yttrium aluminate materials such as YAG, YAM, and YAP.

[0058] In the present invention, the adhesive layer may include a phenyl silicone resin to maintain elongation at low temperatures and reduce brittleness, and may contain an iron oxide component to improve thermal oxidation stability at high temperatures.

[0059] Preferably, the adhesive layer of the present invention has a high elongation over a wide temperature range of -100 to 200°C. The adhesive layer of the present invention may have an elongation at -70°C of 300% or more, 250% or more, 200% or more, 190% or more, 180% or more, 170% or more, 160% or more, or 150% or more after 100 exposures to thermal cycles of 150°C to -70°C. For example, the elongation at -70°C may be 200 to 400%.

[0060] Meanwhile, in the present invention, the elongation of the adhesive layer at room temperature (25°C) after 100 exposures to thermal cycles of 150°C to -70°C may be 100 to 200%. In the present invention, the elongation at room temperature may be 100% or more, 110% or more, 120% or more, 130% or more, 140% or more, or 150% or more.

[0061] In the present invention, elongation can be measured as the rate of change in the elongated length when the sample is broken by a tensile test.

[0062] Preferably, in the present invention, the adhesive of the adhesive layer is preferably phenyl silicone represented by the chemical formula shown in Fig. 2. In addition, in the present invention, the adhesive is preferably one in which iron oxide particles are dispersed.

[0063] Experimental Example 1

[0064] The thermal expansion coefficients of a metal-ceramic composite sintered body with a composition of 70 wt% SiC and 30 wt% Al and a high-purity alumina sintered body manufactured using 99% pure alumina as a raw material were measured at -100°C and 200°C. The thermal expansion coefficients were measured using Netzsch's product name DIL402C. Table 1 below shows the measured thermal expansion coefficients by temperature. Meanwhile, the CTE was calculated by measuring the thermal expansion coefficients by changing the temperature range at intervals of 10°C. c = CTE p The temperature range to which the point (intersection) belongs was obtained.

[0065] Temperature CTE c CTE p CTE c / CTE p Intersection - 100℃3.9*10 -6 6.3*10 -6 0.6250~100℃200℃7.8*10 -6 6.8*10 -6 1.15

[0066] Experimental Example 2

[0067] The coefficient of thermal expansion of a metal-ceramic composite sintered body with a composition of 20 wt% SiC and 80 wt% Al was measured and compared with that of a high-purity alumina sintered body. The coefficient of thermal expansion (CTE) of the composite sintered body at each temperature is shown in Table 2 below. c ) and coefficient of thermal expansion (CTE) of alumina sintered body p ), and the ratio was shown.

[0068] Temperature CTE c CTE p CTE c / CTE p Intersection-100℃13.3*10 -6 6.3*10 -6 2.11-200℃19.1*10 -6 6.8*10 -6 2.81

[0069] <Example 1>

[0070] A susceptor was manufactured using the metal-ceramic composite of Experimental Example 1 as a base member and a high-purity alumina sintered body as a dielectric plate. The susceptor was manufactured in the same shape and size as an electrostatic chuck measuring 300 mm x 300 mm. A silicone resin having a high elongation of 200% or more at low temperatures (-70°C) was used as the adhesive layer of the susceptor. In addition, as a comparative example, a susceptor was manufactured using an aluminum metal material as a base member, a high-purity alumina sintered body as a dielectric plate, and a silicone resin having an elongation of 100% or less at low temperatures, and these were compared.

[0071] The manufactured susceptor was subjected to 200 thermal shock cycles at 50–200°C, and the adhesive shear strength before and after the thermal shock was measured. Shear strength measurements were performed at various locations: the center, middle, and periphery of the susceptor specimen. The measurement results are shown in Table 3 below.

[0072] Distinction CenterMiddleEdgeAvg. Experimental Example 1 Before thermal shock 20.9 23.8 26.5 23.7 After thermal shock 35.4 36.8 40.5 37.6 Comparative Example 1 Before thermal shock 21.2 20.5 23.8 21.8 After thermal shock 8.3 5.2 6.7 6.7

[0073]

[0074] Although the present invention has been described above with reference to exemplary embodiments and drawings, these have been provided only to help a more general understanding of the present invention, and the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains will appreciate that various modifications and variations are possible without departing from the essential characteristics of the present invention. Therefore, the spirit of the present invention should not be limited to the described embodiments, and all technical ideas that are equivalent or equivalent to the claims as well as the claims should be interpreted as being included in the scope of the rights of the present invention.

[0075] The present invention is applicable to a susceptor such as an electrostatic chuck.

Claims

1. A susceptor comprising a base member and a dielectric plate bonded to the base member by an adhesive layer, The above base member is a metal-ceramic composite, A susceptor, wherein the ratio of the coefficient of thermal expansion of the metal-ceramic composite to the ceramic material of the dielectric plate is less than 1.5 over the entire temperature range of -100°C to 200°C.

2. In paragraph 1, A susceptor, wherein the thermal expansion coefficient ratio of the metal-ceramic composite to the ceramic material of the dielectric plate is 1.2 or less over the entire temperature range of -100°C to 200°C.

3. In paragraph 2, A susceptor, wherein the thermal expansion coefficient ratio of the metal-ceramic composite to the ceramic material of the dielectric plate is 0.6 or more over the entire temperature range of -100°C to 200°C.

4. In paragraph 1, A susceptor, wherein the adhesive layer comprises a silicone resin.

5. In paragraph 4, The above adhesive layer is a susceptor having an elastic modulus of 1 MPa to 3 MPa.

6. In paragraph 4, The above adhesive layer is a susceptor having an elongation at -70°C of 200 to 400% after being exposed to 100 thermal cycles of 150°C to -70°C.

7. In paragraph 4, The above adhesive layer is a susceptor having an elongation at room temperature of 100 to 200% after 100 exposures to thermal cycles of 150°C to -70°C.

8. In paragraph 4, The above silicone resin is a susceptor in which inorganic particles are dispersed.

9. In paragraph 8, A susceptor wherein the above inorganic particles contain iron oxide.

10. In paragraph 4, The above silicone resin is a susceptor containing phenyl silicone.

Images