Ceramic base

Abstract

The present invention relates to a ceramic susceptor, and the ceramic susceptor of the present invention may comprise: a base material having a cooling gas flow path for supplying a cooling gas; an insulating plate which is fixed on the base material and has an air hole penetrating through the base material in the thickness direction; and a discharge prevention pin inserted into the air hole and extending along a length direction of the air hole.

Description

Technical Field

[0001] The invention relates to a ceramic base, in particular to an abnormal discharge prevention pin for pores. Background Art

[0002] Typically, a semiconductor device or display device is manufactured by stacking multiple thin film layers including a dielectric layer and a metal layer on a glass substrate, a flexible substrate or a semiconductor wafer substrate in sequence, and then through a patterned semiconductor process. In particular, in a reactive ion etching (RIE) device, a ceramic base may be provided to support a glass substrate, a flexible substrate, a semiconductor wafer substrate, etc. and to be used for a patterned dry etching process, etc. The ceramic base is provided with a high frequency (RF) electrode, so it can also be used to form plasma in an etching process (etching process) of a thin film layer formed on a substrate, etc. Furthermore, the ceramic base may also be provided with a suction cup electrode for supporting a substrate or a heating wire for heating a substrate, etc.

[0003] Figure 1a to Figure 1c This is a diagram for explaining the problems of the conventional ceramic susceptor. Figure 1a and Figure 1b This is a diagram showing an example of arcing occurring in a pore portion during a dry etching process or the like of a conventional ceramic base. Figure 1c It is a diagram showing a state of wear of a discharge prevention pin inserted into a gas hole of a conventional ceramic base.

[0004] Reference Figure 1a to Figure 1c Generally, the life of a ceramic base is 5,000 to 15,000 hours, and can be used for about 10 to 30 months depending on the use environment. At this time, the discharge prevention pins applied to the pores of the ceramic base are exposed to plasma for a long time and produce Figure 1c Thus, when the discharge prevention pin, which is usually inserted into a pore with a diameter of less than 1 mm, has poor plasma resistance, such as Figure 1a and Figure 1b As shown in the figure, there is a problem of severe wear that induces arcing. This determines the life of the ceramic base, so it needs to be improved. Summary of the invention

[0005] Problem that the invention aims to solve

[0006] Therefore, the present invention is proposed to solve the above-mentioned problems, and an object of the present invention is to provide a ceramic base which can reduce the occurrence of arcs and increase the life of the ceramic base by improving the plasma resistance of the discharge prevention pins of the pores.

[0007] Means used to solve problems

[0008] First, summarizing the features of the present invention, a ceramic base of one aspect of the present invention for achieving the purpose may include: a substrate having a cooling gas flow path for supplying cooling gas; an insulating plate fixed on the substrate and having pores extending through the substrate in the thickness direction; and a discharge prevention pin inserted into the pore and extending along the length direction of the pore.

[0009] The discharge preventing pin is preferably made of a material having a volume resistance in the range of 1E14 Ωcm to 1E15 Ωcm.

[0010] The cross-sectional area of ​​the end of the discharge prevention pin may be 50% to 90% of the cross-sectional area of ​​the pore.

[0011] The discharge preventing pin may include an Al2O3-SiC composite material.

[0012] The Al2O3-SiC composite material may preferably contain 3wt% to 10wt% of SiC.

[0013] The volume resistance of the Al2O3-SiC composite material at room temperature may preferably be greater than 1E15Ωcm, and the volume resistance at a temperature of 200°C may be greater than 1E14Ωcm.

[0014] The discharge preventing pin may be inserted into the air hole having a diameter of 1 mm or less.

[0015] The ceramic base may include an electrode layer located within the insulating plate, and the electrode layer may include one or more of an electrostatic chuck electrode, a high-frequency electrode, or a heating wire.

[0016] Effects of the Invention

[0017] According to the ceramic base of the present invention, as a material for the discharge prevention pin of the pore, a material in which 3wt% to 10wt% of SiC is mixed in Al2O3 can be used, so that the plasma etching rate is maintained in the range of 0.02μm / minute to 0.1μm / minute, and the volume resistance of the material is above 1E15Ωcm at room temperature and above 1E14Ωcm at a temperature of 200°C, thereby improving the plasma resistance and increasing the life of the ceramic base. That is, the discharge prevention pin of the present invention will not wear out due to the improvement of the plasma resistance, so no space for electron acceleration will be formed in the pores, thereby not causing abnormal discharge. In addition, by maintaining the volume resistance of the above-mentioned material, the occurrence of a high potential difference that can induce abnormal discharge at high resistance can be prevented, and the increase of current that can induce abnormal discharge at low resistance can be prevented. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] To help understanding of the present invention, the accompanying drawings, which are included as a part of the detailed description, provide embodiments of the present invention and, together with the detailed description, serve to explain the technical concept of the present invention.

[0019] Figure 1a to Figure 1c This is a diagram for explaining the problems of the conventional ceramic susceptor.

[0020] Figure 2 This is a schematic cross-sectional view of a ceramic base according to an embodiment of the present invention.

[0021] Figure 3 yes Figure 2 An enlarged cross-sectional view of the AA portion.

[0022] Figure 4 It is used to illustrate Figure 2 Figure 2. Abnormal discharge in the pore part of the prevention pin caused by wear abnormal discharge.

[0023] Figure 5 The photographs are actual experimental photographs showing a clean state without abnormal discharge around the pores on the upper end surface of the ceramic susceptor according to one embodiment of the present invention.

[0024] Description of Reference Numerals

[0025] 15: Cooling gas flow path

[0026] 30: Stoma

[0027] 55: Discharge prevention pin

[0028] 200: Base material

[0029] 300: Insulation board

[0030] 320: Electrode layer DETAILED DESCRIPTION

[0031] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. At this time, in each of the accompanying drawings, the same components are represented by the same figure numerals as much as possible. In addition, the detailed description of the known functions and / or structures will be omitted. The content disclosed below focuses on the parts required for understanding the actions of various embodiments, and omits the description of the elements that make the main purpose of the description unclear. In addition, some of the components in the drawings may be enlarged or omitted, or shown schematically. The size of each component does not fully reflect the actual size, so the content recorded here is not limited to the relative size or spacing of the components shown in each of the accompanying drawings.

[0032] In the process of describing the embodiments of the present invention, when it is judged that the specific description of the known technology related to the present invention unnecessarily obscures the main idea of ​​the present invention, the detailed description thereof will be omitted. Moreover, the terms described below, as terms defined in consideration of the functions in the present invention, can be changed according to the intention or convention of the user, operator. Therefore, it should be defined based on the content of the full text of this specification. The terms used in the detailed description are only used to describe the embodiments of the present invention and should not be restrictive. Unless otherwise explicitly stated, the expression of a single number of forms includes the meaning of a plurality of numbers of forms. In the process of this description, expressions such as "including" or "provided with" are used to indicate certain characteristics, numbers, steps, actions, elements and a part or combination thereof, and should not be interpreted as excluding the existence or possibility of one or more other characteristics, numbers, steps, actions, elements and a part or combination thereof other than those described.

[0033] In addition, terms such as “first” and “second” may be used to describe a plurality of components, but the components are not limited to the terms, and the terms are only used to distinguish one component from other components.

[0034] First, in the present invention, the ceramic base is a semiconductor device used to process substrates for various purposes (such as semiconductor wafers, glass substrates, flexible substrates, etc.), and in order to support the substrate, an electrostatic chuck electrode used as an electrostatic chuck can be provided, and in order to heat the substrate at a specified temperature, a heating wire (or heating element) for a heater can be provided, or in order to perform a process (plasma enhanced chemical vapor deposition, etc.) on the substrate, a high-frequency electrode can be provided, or the high-frequency electrode can be used instead of the heating wire. For example, the ceramic base of the present invention can be applied not only to reactive ion etching (RIE) equipment, but also to equipment used in chemical vapor deposition (CVD) process and physical vapor deposition (PVD) process.

[0035] Therefore, as described below, the ceramic base of the present invention mentioned is a structure in which a substrate including a cooling gas flow path and an insulating plate including an electrode layer are bonded, and it is previously explained that the electrode layer arranged on the insulating plate should be understood to include a conductor, and the conductor is used to realize any one or more functions of the electrostatic suction cup electrode, high-frequency electrode, or heating wire (or heating element) as described above.

[0036] Figure 2 FIG. 1 is a schematic cross-sectional view of a ceramic base 100 according to an embodiment of the present invention.

[0037] Reference Figure 2The ceramic base 100 of one embodiment of the present invention includes a substrate 200 and an insulating plate 300 bonded by an adhesive 312. The ceramic base 100 is preferably circular, but may also be designed in other shapes such as an ellipse and a quadrilateral according to circumstances.

[0038] The substrate 200 may be formed as a multi-layer structure consisting of a plurality of metal layers. These metal layers may be bonded by a brazing process, a welding process, a bonding process, or the like. The insulating plate 300 is fixed to the substrate 200 and may be fixed to the substrate 200 using a prescribed fixing unit or a bonding / bonding unit. The substrate 200 and the insulating plate 300 may be prepared separately and then bonded. Depending on the situation, the structure of the insulating plate 300 may also be directly formed on the upper surface of the substrate 200 using a ceramic sheet or the like.

[0039] like Figure 2 The insulating plate 300 includes an electrode layer 320 disposed between ceramic sheets or ceramic materials using powder. As an embodiment, the ceramic material can be made of a material selected from aluminum oxide (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, YAG, YAM, YAP and the like. The insulating plate 300 can be formed by thermal spraying the above-mentioned ceramic material on the upper surface of the substrate 200 and attaching a ceramic sheet.

[0040] The electrode layer 320 may be made of a conductive metal material. As an example, the electrode layer 320 may be formed of at least one of silver (Ag), gold (Au), nickel (Ni), tungsten (W), molybdenum (Mo) and titanium (Ti), and more preferably, may be formed of tungsten (W). The electrode layer 320 may be formed using a thermal spraying process or a screen printing process. The electrode layer 320 has a thickness of about 1.0 μm to 100 μm. For example, preferably, when the electrode layer 320 is formed by a screen printing process, a thickness of 1.0 μm to 30 μm may be applied, and when the electrode layer 320 is formed by a thermal spraying process, a thickness of 30 μm to 100 μm may be applied. However, it is difficult to form an overly thin layer (such as the thickness of the electrode layer 320 is less than 1.0 μm, etc.), so it is not preferred. In addition, at this time, the porosity and other defects in the electrode layer will cause the resistance value to increase, and the phenomenon of reduced electrostatic adsorption force may occur according to the increase in the resistance value, so it is not preferred. In addition, when the thickness of the electrode layer 320 is too thick (such as more than 100 μm), arcing may occur, so it is not preferred. Therefore, the thickness of the electrode layer 320 is preferably in the range of about 1.0 μm to 100 μm. As an example, the electrode layer 320 formed in the above manner can be an electrostatic chuck electrode as described below, which can receive a bias and generate an electrostatic force when loading a substrate (not shown) placed on the upper part of the dielectric layer 330, thereby clamping (chucking), and when unloading the substrate (not shown), the opposite bias is applied to the electrode layer 320 to cause discharge to release the clamping.

[0041] However, it is not limited to this, and depending on the situation, the electrode layer 320 may also include an electrode pattern for a heater or a high-frequency electrode pattern for generating plasma. That is, the ceramic base 100 of the present invention is a semiconductor device for processing a processing target substrate (semiconductor wafer, glass substrate, flexible substrate, etc.) for various purposes. In order to support the processing target substrate, an electrostatic chuck electrode may be provided on the electrode layer 320 used as an electrostatic chuck, and a heating wire (or heating element) may be provided in order to heat the processing target substrate at a specified temperature, or a high-frequency electrode may be provided in order to perform a process (plasma enhanced chemical vapor deposition, etc.) on the processing target substrate, or a high-frequency electrode may be used instead of a heating wire.

[0042] When the ceramic base 100 is installed inside a chamber used for semiconductor processing, in order to use external cooling gas to uniformly cool the substrate on the insulating plate 300 (for example, a glass substrate, a flexible substrate, and a semiconductor wafer substrate, etc.), a plurality of cooling holes 30 formed on the insulating plate 300 may be provided, and the plurality of cooling holes 30 are fluidically connected to the cooling gas flow path 15 of the substrate 200.

[0043] In addition, in the ceramic base 100 of the present invention, each discharge prevention pin 55 is inserted into each pore 30. For example, in a semiconductor process (etching process, etc.), when an RF high-frequency voltage or a low-frequency voltage is applied to the electrode layer 320 simultaneously or separately through the electrode rod 281 of the substrate 200, abnormal discharge (micro arcing or parasitic plasma, etc.) can be suppressed to allow the etching process to proceed stably.

[0044] Figure 3 yes Figure 2 An enlarged cross-sectional view of the AA portion.

[0045] Reference Figure 3 For example, the interior of the substrate 200 has a suitable pattern (such as Figure 2 The cooling gas flow path 15 is provided with a cooling gas flow path 15 (as shown in the figure), and the cooling gas flow path 15 is used to supply cooling gas. The cooling gas flow path 15 can be pre-formed in the metal material of the substrate 200. For example, as shown in the figure, the upper end of the cooling gas flow path 15 can also be a through hole formed on the pore structure 50 included in the substrate 200. In the preparation process of the ceramic base 100 of the present invention, the insulating plate 300 can be bonded to the substrate 200 using an adhesive 312.

[0046] The substrate 200 and the insulating plate 300 can be firmly bonded by pressing, sintering and curing. Next, a hole for penetrating the insulating plate 300 and the adhesive layer of the adhesive 312 can be processed at the position of the pore 30 by machining of a machining center (MCT) or the like, or a hole can be processed to further penetrate the pore structure 50 of the substrate 200 as needed, so that fluid communication is formed between the cooling gas flow path 15 and the pore 30. The above-mentioned hole processing can use MCT laser processing or the like, so that a hole with a diameter of less than several millimeters can be processed, or preferably, a hole with a diameter of less than 1 mm can be processed.

[0047] The cooling air holes 30 of the insulating plate 300 that penetrate the insulating plate 300 as described above in the thickness direction can eject the cooling gas from the cooling gas flow path 15 to uniformly cool the substrate on the insulating plate 300. Here, "penetrating in the thickness direction" means that the air holes 30 are set to provide a passage of any shape connecting the upper surface and the lower surface of the insulating plate 300, and the specific penetration shape can be used in a way that penetrates the entire insulating plate 300 from the surface of the insulating plate 300 directly downward, or through a combination of vertical channels and horizontal channels. At this time, helium (He) can be used as the cooling gas, but it is not limited to this. The cooling air holes 30 of the insulating plate 300 can be composed of an appropriate number according to the design.

[0048] exist Figure 2In the embodiment, a bias voltage may be applied to the electrode layer 320 from one or more electrode rods 281 provided in a manner passing through the lower hole 280 of the ceramic base 100, and the bias voltage is used for clamping and releasing the clamping, or for providing heating or high frequency. According to the design, the cooling air holes 30 may be formed in an appropriate number between the prescribed electrode patterns forming the electrode layer 320, and the cooling air holes 30 may be used to achieve fluid communication of the cooling gas from the cooling gas flow path 15 to the upper surface of the insulating plate 300.

[0049] Furthermore, in the ceramic base 100 of the present invention, each discharge prevention pin 55 is inserted into each cooling hole 30. For example, in a semiconductor process (etching process, etc.), when an RF high-frequency voltage or a low-frequency voltage is applied to the electrode layer 320 simultaneously or separately through the electrode rod 281 of the substrate 200, abnormal discharge (micro arcing or parasitic plasma, etc.) can be suppressed to allow the etching process to proceed stably.

[0050] The discharge preventing pin 55 is inserted into the air hole 30 having a diameter of several millimeters or less, or preferably a diameter of 1 mm or less, and the diameter of the discharge preventing pin 55 is appropriately smaller than the diameter of the air hole 30. For example, the cross-sectional area of ​​the end of the discharge preventing pin 55 is preferably 50% to 90% of the cross-sectional area of ​​the air hole 30, and thus, it is preferred that the cooling gas passes through the gap between the air hole 30 and the discharge preventing pin 55 to fully form fluid communication.

[0051] The discharge prevention pin 55 can be inserted into the air hole 30 and extend downward along the length direction of the air hole 30, so that it can be fixed in a variety of fixing methods and prevent the discharge prevention pin 55 from protruding above the air hole 30. For example, preferably, the end height of the air hole 30 is the same as the end height of the discharge prevention pin 55. However, the end height of the discharge prevention pin 55 should be above the end height of the air hole 30.

[0052] Figure 4 It is used to illustrate Figure 2 FIG. 30 is a diagram showing abnormal discharge caused by wear of the abnormal discharge prevention pin 55 in the air hole 30 portion.

[0053] Reference Figure 4 , the discharge prevention pin 55 can ensure that the process using plasma is carried out stably. However, when there is no discharge prevention pin 55 or the upper end of the discharge prevention pin 55 is worn and a space 490 is generated at the upper end of the air hole 30 as shown in the figure, during the process using the above plasma in the semiconductor device, depending on the conditions such as the gas pressure and voltage in the reactor and the size (maximum distance or volume) of the space 490, abnormal discharge is generated in the air hole 30, and the following is induced: Figure 1a and Figure 1b The arc shown makes it impossible to carry out the plasma process.

[0054] In order to suppress the abnormal discharge in the ceramic base 100 , it is important to prevent the discharge prevention pin 55 from being worn to prevent the space 490 from being generated at the upper end of the air hole 30 so that the electrons cannot be accelerated in the space 490 .

[0055] To this end, preferably, the discharge prevention pin 55 includes an Al2O3-SiC composite material, for example, the Al2O3-SiC composite material may contain 3wt% to 10wt% of SiC. Preferably, the Al2O3-SiC composite material has a volume resistivity of 1E15Ωcm or more at room temperature and a volume resistivity of 1E14Ωcm or more at a temperature of 200°C.

[0056] The following Table 1 summarizes the data of arithmetic mean roughness (Ra), ten-point average roughness (Rz), etching depth and etching rate of various comparative materials (SiC, Al2O3+SiC mixture and more than 99.9% pure Al2O3) within 10 minutes of etching time under a specified plasma generation environment.

[0057] Table 1

[0058]

[0059] Generally, pure Al2O3 is a brittle material with high strength and high density. In order to realize a material resistant to thermal shock, a material mixed with SiC is used to prepare the discharge prevention pin 55. In particular, as shown in Table 1, the plasma etching rate of the discharge prevention pin 55 made of the mixed material of Al2O3 (for example, 90wt% to 97wt%) and SiC (for example, 3wt% to 10wt%) can be in the range of 0.02μm / min to 0.1μm / min (for example, 0.03μm / min), so even in the in-situ plasma process of dry etching, the etching rate is not high, thereby preventing the discharge prevention pin 55 in the pore 30 from being worn and preventing the space 490 from being generated at the upper end of the pore 30. In a reactive ion etching (RIE) device, etc., the etching rate is measured under ordinary process conditions for dry etching, but can be slightly changed according to the process conditions.

[0060] At this time, the volume resistance of the discharge prevention pin 55 is shown to be 1E15Ωcm or more at room temperature and 1E14Ωcm or more at a temperature of 200°C, and the potential difference in the upper end space 490 of the air hole 30 can be suppressed to prevent electrons from being accelerated in the space 490, thereby preventing abnormal discharge. The reason is that when the volume resistance of the discharge prevention pin 55 is 1E16Ωcm or more, the potential difference can be increased in the air hole 30 to generate an arc, and when the volume resistance of the discharge prevention pin 55 is 1E14Ωcm or less, the current is concentrated on the discharge prevention pin 55, which may cause changes in process characteristics (plasma etching, etc.) due to abnormal discharge, etc.

[0061] Figure 5 The photographs are actual experimental photographs showing a clean state without abnormal discharge around the pores 30 on the upper end surface of the ceramic susceptor 100 according to an embodiment of the present invention.

[0062] like Figure 5 As shown, for example, it is confirmed that the ceramic base 100 of one embodiment of the present invention, which uses a discharge prevention pin 55 made of a mixed material of Al2O3 (e.g., 90wt% to 97wt%) and SiC (e.g., 3wt% to 10wt%), maintains a clean state without abnormal discharge around the pores 30.

[0063] As described above, according to the ceramic base 100 of the present invention, as a material of the discharge prevention pin 55 of the pore 30, for example, a material in which 3wt% to 10wt% of SiC is mixed in Al2O3 can be used, so that the plasma etching rate is maintained in the range of 0.02μm / min to 0.1μm / min, and the volume resistance of the material is 1E15Ωcm or more at room temperature and 1E14Ωcm or more at a temperature of 200°C, thereby improving the plasma resistance and increasing the life of the ceramic base 100. That is, the discharge prevention pin 55 of the present invention will not wear due to the improvement of the plasma resistance, so that no space for electron acceleration is formed in the pore, thereby not causing abnormal discharge. In addition, by maintaining the volume resistance of the above-mentioned material, the occurrence of a high potential difference that can induce abnormal discharge at high resistance can be prevented, and the increase of current that can induce abnormal discharge at low resistance can be prevented.

[0064] As described above, in the present invention, specific matters such as specific constituent elements and limited embodiments and drawings are used for explanation, but this is only provided for a more comprehensive understanding of the present invention, and the present invention is not limited to the embodiments, and a person of ordinary skill in the technical field to which the present invention belongs can make various modifications and variations within the scope of the essential characteristics of the present invention. Therefore, the idea of ​​the present invention should not be limited to the embodiments described, and not only the claims described later, but all technical ideas that are equivalent to or have equivalent variations of the claims should be interpreted as being included in the scope of the present invention.

Claims

1. A ceramic base, characterized in that: include: a substrate having a cooling gas flow path for supplying a cooling gas, an insulating plate fixed on the substrate and having pores penetrating in the thickness direction, and a discharge prevention pin inserted into the air hole and extending along the length direction of the air hole; The discharge preventing pin includes an Al2O3-SiC composite material, and the Al2O3-SiC composite material has a volume resistance of 1E14 Ωcm or more at a temperature of 200°C.

2. The ceramic base according to claim 1, characterized in that: The discharge prevention pin is made of a material having a volume resistance in the range of 1E14 Ωcm to 1E15 Ωcm.

3. The ceramic base according to claim 1, characterized in that: The cross-sectional area of ​​the end of the discharge prevention pin is 50% to 90% of the cross-sectional area of ​​the pore.

4. The ceramic base according to claim 1, characterized in that: In the Al2O3-SiC composite material, the content of SiC is 3wt% to 10wt%.

5. The ceramic base according to claim 1, characterized in that: The volume resistance of the Al2O3-SiC composite material at room temperature is above 1E15Ωcm.

6. The ceramic base according to claim 1, characterized in that: The discharge prevention pin is inserted into the air hole having a diameter of 1 mm or less.

7. The ceramic base according to claim 1, characterized in that: The ceramic base includes an electrode layer located within the insulating plate, The electrode layer includes at least one of an electrostatic chuck electrode, a high-frequency electrode, or a heating wire.

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