Ceramic heater

Abstract

The utility model provides a kind of ceramic heater.The ceramic heater includes base and heating main body.Heating main body is arranged below base, with a symmetrical ceramic sandwich structure.Symmetrical ceramic sandwich structure includes first ceramic layer, electrode film layer and second ceramic layer sequentially stacked along height. Among them, electrode film layer is embedded between first ceramic layer and second ceramic layer, and second ceramic layer is laminated with first ceramic layer to form an integrated structure.Compared with prior art, the utility model realizes complete isolation with external environment by embedding electrode film layer completely and sealing between first ceramic layer and second ceramic layer, prevents electrode oxidation, solves the problems such as traditional surface printing electrode being easily mechanically scratched and damaged, being corroded by etching gas in process environment, etc.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor manufacturing technology, and in particular to a ceramic heater. Background Technology

[0002] In the wafer manufacturing process, heat treatment is a crucial step, placing extremely stringent requirements on the temperature uniformity, heating rate, long-term stability, and environmental tolerance of the heating platform. Ceramic heaters, due to their excellent thermal conductivity, insulation, and high-temperature resistance, are widely used in this field.

[0003] Traditional ceramic heaters primarily employ methods such as screen printing to directly print electrode paste onto the surface of a ceramic substrate, followed by sintering to form the electrode circuit. The surface-printed electrodes are directly exposed to the working environment, facing direct risks of mechanical scratch damage, chemical gas corrosion, and solder infiltration contamination. Furthermore, exposed electrodes are prone to oxidation, leading to resistance drift. Additionally, exposed electrodes also experience heat loss to the surrounding environment, reducing thermal efficiency.

[0004] In view of this, it is indeed necessary to propose a ceramic heater to solve the above problems. Utility Model Content

[0005] The purpose of this invention is to provide a ceramic heater that, through an embedded electrode design, effectively prevents electrode oxidation and ensures excellent thermal uniformity of the heating surface.

[0006] Therefore, the present invention provides a ceramic heater, comprising: Base; The heating element, located below the base, has a symmetrical ceramic sandwich structure; The symmetrical ceramic sandwich structure includes a first ceramic layer, an electrode film layer, and a second ceramic layer stacked sequentially along its height; wherein the electrode film layer is embedded between the first ceramic layer and the second ceramic layer, and the second ceramic layer is laminated with the first ceramic layer to form an integral structure.

[0007] Optionally, electrode paste is printed on a thick film on the first ceramic layer to form an electrode film layer.

[0008] Optionally, an electrode body is provided on the electrode film layer, and the electrode body has multiple concentric arc portions and multiple connecting portions for connecting the arc portions.

[0009] Optionally, the creepage distance between the two ends of the electrode body is ≥10mm, and the two ends of the electrode body are positive and negative terminals, respectively, for connecting to a power source.

[0010] Optionally, the electrode body is a molybdenum electrode.

[0011] Optionally, the ring width of the arc portion is 4.5mm, the distance between two adjacent arc portions is 2.5mm, and the thickness of the arc portion is 0.7mm.

[0012] Optionally, the base and the heating body are annular. The base includes a first base and a second base arranged vertically, with the second base abutting against the heating body. The first base has a first annular groove on the side facing the second base, and the second base has a second annular groove on the side facing the first base. The first annular groove and the second annular groove are arranged opposite to each other and together form a closed cooling channel. The first base has an inlet and an outlet that communicate with the cooling channel.

[0013] Optionally, the base is provided with a conductive component, and the conductive component contains a conductive element that is electrically connected to the electrode body. The base also includes a first base and a second base arranged vertically. The first base and the second base are provided with installation spaces for the conductive element to pass through at the positive and negative positions of the electrode film. The conductive element is installed in the installation space by means of a ceramic gasket and abuts against the electrode film.

[0014] Optionally, the conductive component also includes a semi-circular washer and a retaining spring. The conductive element is placed inside the ceramic washer, and the retaining spring is engaged with the conductive element. The semi-circular washer is fixedly connected to the base, and the semi-circular washer covers the retaining spring.

[0015] Optionally, there is a gap between the bottom end of the ceramic gasket and the bottom of the second base, and the space between the bottom end of the ceramic gasket and the mounting space is filled with fixing adhesive.

[0016] Compared with the prior art, the technical solution of the embodiments of this utility model has the following beneficial effects: This invention relates to a ceramic heater that completely isolates the electrode film layer from the external environment by embedding and sealing it between the first and second ceramic layers. This prevents electrode oxidation and solves problems such as mechanical scratch damage, corrosion by etching gases in the process environment, and contamination by solder or other pollutants in traditional surface-printed electrodes. The electrode film layer is located inside the heating element, bringing the heat source closer to the workpiece, reducing thermal resistance, and achieving faster thermal response and higher heating efficiency. Furthermore, the symmetrical sandwich structure of the "first ceramic layer - electrode film layer - second ceramic layer" ensures that the coefficients of thermal expansion (CTE) of the materials on both sides of the electrode film layer (heating element) are perfectly symmetrical. During thermal cycling, the generated thermal stress can be effectively offset by the symmetrical ceramic layers on both sides, greatly improving the thermal stress distribution and preventing ceramic warping or cracking caused by stress concentration. This ensures high flatness and excellent thermal uniformity of the heating surface, meeting the stringent requirements of high-end semiconductor manufacturing processes. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a ceramic heater conforming to a preferred embodiment of the present utility model; Figure 2 yes Figure 1 Exploded view of the installation of the ceramic heater; Figure 3 yes Figure 1 A cross-sectional view of a ceramic heater; Figure 4 This is a schematic diagram of the structure of the first base conforming to the preferred embodiment of the present utility model; Figure 5 yes Figure 4 A structural diagram of the first base from another angle; Figure 6 This is a schematic diagram of the structure of the second base conforming to the preferred embodiment of the present utility model; Figure 7 yes Figure 1 Another cross-sectional view of the ceramic heater; Figure 8 yes Figure 7 A partial view of the circled area; Figure 9 This is a schematic diagram of the structure of a semi-circular gasket conforming to a preferred embodiment of the present utility model; Figure 10 This is a schematic diagram of the structure of the heating body conforming to the preferred embodiment of the present utility model; Figure 11 yes Figure 10 Cross-sectional view of the central heating element; Figure 12 yes Figure 10 A schematic diagram of the heating element without the second ceramic layer; Figure 13 This is a schematic diagram of the electrode film layer according to a preferred embodiment of the present invention; Figure 14 This is a schematic diagram of the structure of the electrode film layer according to another embodiment of the present invention.

[0018] The components in the attached diagram are labeled as follows: Base 1, first base 11, first annular groove 111, first arc-shaped ridge 1111, water inlet 112, water outlet 113, annular boss 114, first through hole 1141, fixing hole 1142, second base 12, second annular groove 121, fixing ridge 122, second through hole 1221, cooling channel 13, conductive component 14, conductive element 141, wire 1411, external terminal 1412, ceramic gasket 142, semi-circular gasket 143, mounting hole 1431, limiting part 1432, mounting groove 1433, snap ring 144; Heating body 2, first ceramic layer 21, electrode film layer 22, electrode body 221, arc portion 2211, connecting portion 2212, first terminal 2213, second terminal 2214, second ceramic layer 23, conductive hole 231; Ceramic heater 100. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] It should be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0021] Additionally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0022] Please see Figures 1 to 14 As shown, an embodiment of the present invention provides a ceramic heater 100, which is a device for supporting heat-treated objects (semiconductor wafers, glass substrates, flexible substrates, etc.) for various purposes and heating the heat-treated objects at a predetermined temperature.

[0023] The ceramic heater 100 includes a base 1 and a heating body 2 disposed below the base 1. The heating body 2 and the base 1 are connected by a film. Preferably, a high-temperature resistant thermally conductive silicone sheet is used to connect the heating body 2 and the base 1. The thermally conductive silicone sheet has good thermal conductivity and insulation properties, which can reduce the contact thermal resistance between the surface of the heating body 2 and the contact surface of the base 1, allowing for better and fuller contact between the heating body 2 and the base 1, achieving true face-to-face contact, thus ensuring flatness and thermal uniformity, and minimizing temperature differences in temperature response.

[0024] In this embodiment, the ceramic heater 100 is annular, meaning both the base 1 and the heating body 2 are annular. The base 1 is a metal base, specifically an aluminum base in this embodiment.

[0025] Please see Figures 1 to 6 As shown, the base 1 includes a first base 11 and a second base 12 arranged vertically. The first base 11 and the second base 12 are connected by diffusion welding, that is, the first base 11 and the second base 12 are welded together by diffusion welding. The second base 12 abuts against the heating body 2.

[0026] The first base 11 has a first annular groove 111 on the side facing the second base 12, and the two ends of the first annular groove 111 are not connected. The second base 12 has a second annular groove 121 on the side facing the first base 11, and the two ends of the second annular groove 121 are not connected. A cooling channel 13 is formed between the first annular groove 111 and the second annular groove 121.

[0027] The first base 11 is provided with an inlet 112 and an outlet 113, which are located at the two ends of the first annular groove 111 and are connected to the cooling channel 13. The coolant enters the cooling channel 13 through the inlet 112, absorbs heat, and then flows out from the outlet 113.

[0028] In some embodiments, the coolant can be cooling water. Cooling channel 13 prevents heat conduction to the sealing area, avoiding seal failure, leakage, or damage. It also protects sensors, cables, gas connectors, etc., near the sealing area. Wafer reaction chambers often require a vacuum or special gas environment, relying on various sealing rings (such as O-rings). The temperature limits of these sealing materials are far lower than the operating temperature of ceramic rings.

[0029] The first base 11 has an annular boss 114 on the side opposite to the second base 12. The annular boss 114 has two first through holes 1141 and one fixing hole 1142. The fixing hole 1142 is located between the two first through holes 1141. A first arc-shaped ridge 1111 is provided within the first annular groove 111. Both first through holes 1141 pass through the first arc-shaped ridge 1111.

[0030] The second base 12 has a fixing ridge 122 on the side facing the first base 11. The fixing ridge 122 has two spaced second through holes 1221 that penetrate the fixing ridge 122. The two second through holes 1221 correspond one-to-one with the two first through holes 1141. The first through holes 1141 and the second through holes 1221 are connected to form an installation space.

[0031] Please see Figures 7 to 9 As shown, a conductive component 14 is provided on the base 1. The conductive component 14 contains two conductive elements 141 electrically connected to the electrode film layer 22. The two conductive elements 141 are respectively installed within the installation space. Both conductive elements 141 pass through the first base 11 and the second base 12 and then abut against the electrode film layer 22 for conductive contact.

[0032] In this embodiment, the conductive element 141 is a contact pin, which is connected to a wire 1411, which is used to connect to an external power source.

[0033] Specifically, the conductive component 14 also includes a ceramic gasket 142, a retaining spring 144, and a semi-circular gasket 143 installed within the annular boss 114. The semi-circular gasket 143, retaining spring 144, and ceramic gasket 142 are arranged sequentially along their height. The conductive component 141 is mounted within the first through hole 1141 and the second through hole 1221, with the ceramic gasket 142 providing a limiting position. The retaining spring 144 is installed between the ceramic gasket 142 and the semi-circular gasket 143. Specifically, the contact pin is placed in the ceramic gasket 142, and the retaining spring 144 engages with the contact pin, after which the semi-circular gasket 143 is installed.

[0034] A semi-circular washer 143 is fixedly connected to the base 1, and the semi-circular washer 143 covers the retaining spring 144. The two ends of the semi-circular washer 143 have mounting holes 1431 communicating with the first through hole 1141 and the second through hole 1221. A stylus is inserted sequentially through the mounting holes 1431 into the first through hole 1141 and the second through hole 1221. A mounting groove 1433 is provided in the center of the semi-circular washer 143 for mounting screws or bolts. The screw passes sequentially through the mounting groove 1433 and the fixing hole 1142 and is threaded into the base 1 to fix the base 1 and the semi-circular washer 143 together.

[0035] The stylus has a wire 1411 inside, which is soldered to two external terminals 1412. One end of one external terminal 1412 is connected to the stylus, and the other external terminal 1412 is connected to the electrode film layer 22 of the heating body 2.

[0036] Preferably, the bottom end of the ceramic gasket 142 and the bottom of the second through hole 1221 are filled with adhesive (fixing adhesive) to enhance the fixing effect of the external terminal 1412 in the conductive component 141. After the external terminal 1412 is soldered, the adhesive filling can further enhance the fixing effect and avoid the risk of the external terminal 1412 falling off.

[0037] A limiting part 1432 is provided on the side of the semi-circular gasket 143 facing the first base 11. The limiting part 1432 abuts against the ceramic gasket 142 and plays a limiting role for the ceramic gasket 142.

[0038] Please see Figures 10 to 14As shown, the heating body 2 is made of ceramic material, which greatly improves corrosion resistance compared to traditional metal heaters. In this embodiment, the heating body 2 is mainly made of aluminum nitride ceramic. The heating body 2 has a symmetrical ceramic sandwich structure. The symmetrical ceramic sandwich structure includes a first ceramic layer 21, an electrode film layer 22, and a second ceramic layer 23 stacked sequentially along the height. The electrode film layer 22 is embedded between the first ceramic layer 21 and the second ceramic layer 23, and the second ceramic layer 23 is laminated with the first ceramic layer 21 to form an integral structure. The heating body 2 adopts a three-dimensional sandwich structure of "first ceramic layer 21 - electrode film layer 22 - second ceramic layer 23". That is, the electrode film layer 22 is completely embedded in the center of the heating body 2, so that the electrode film layer 22 is isolated from the environment, effectively reducing the oxidation and volatilization problem of the electrode film layer 22 during multi-layer co-firing. It also eliminates the potential mechanical scratch damage, environmental corrosion risk, and solder penetration contamination problems of the electrode film layer 22. The ceramic heater 100 has changed from the traditional surface-printed electrode to an embedded electrode, which solves the risk of electrode exposure and eliminates the problems of mechanical scratches, electrode oxidation and corrosion that exist in traditional surface electrodes.

[0039] Furthermore, electrode paste is printed on the first ceramic layer 21 to form an electrode film layer 22. An electrode body 221 is provided on the electrode film layer 22. The electrode body 221 can be formed of tungsten (W), molybdenum (Mo), molybdenum carbide (Mo2C), (MoC), (Mo3C2), niobium (Nb), or alloys thereof. In this embodiment, the electrode material of the electrode film layer 22 is molybdenum. The electrode body 221, made of molybdenum, is printed inside the aluminum nitride ceramic.

[0040] Preferably, the first ceramic layer 21 is printed with electrode paste using thick film printing technology to form the electrode film layer 22, so that the electrode thickness is consistent and the heating is uniform.

[0041] The electrode body 221 has a first terminal 2213 and a second terminal 2214 at both ends, which are the positive and negative terminals, respectively, for connecting to a power source. After the positive and negative terminals of the electrode body 221 become conductive, they have an adsorption function. There is a creepage distance between the two ends of the electrode body 221. A safe creepage distance is maintained between the positive and negative terminals of the electrode body 221 to ensure electrical safety.

[0042] In this embodiment, the creepage range between the positive and negative electrodes of the electrode body 221 is ≥10mm to ensure electrical safety.

[0043] The second ceramic layer 23 is stacked on the first ceramic layer 21. The electrode film layer 22 is completely embedded in the center of the heating body 2, isolating the molybdenum electrode from the environment to reduce the oxidation and volatilization of the molybdenum electrode during multilayer co-firing, and eliminating the mechanical scratch damage and solder penetration contamination problems caused by the exposure of traditional surface electrodes. Two conductive holes 231 are provided on the second ceramic layer 23 at the corresponding positive and negative electrode positions, so that the stylus can be connected to the positive and negative electrodes of the electrode body 221 through the conductive holes 231.

[0044] The electrode body 221 has multiple arcuate portions 2211 and multiple connecting portions 2212 for connecting the arcuate portions 2211. Starting from the first terminal 2213, the electrode body 221 forms a certain pattern (such as concentric circles), and after continuous wiring on the electrode film layer 22, it is connected to the second terminal 2214. In this process, the electrode body 221 in the inner region can be folded at the multiple connecting portions 2212 and form a shape with multiple concentric circle patterns.

[0045] Specifically, the multiple concentric arc portions 2211 increase the uniformity of current density, increase the effective heating area, and improve thermal uniformity compared to traditional linear electrodes. In this embodiment, the electrode film layer 22 has three concentric arc portions 2211, namely a first arc portion, a second arc portion, and a third arc portion with successively increasing radii.

[0046] Multiple connecting portions 2212 are used to connect adjacent arc portions 2211 among multiple concentric arc portions 2211. In this embodiment, the multiple connecting portions 2212 are first connecting portions and second connecting portions. The first connecting portion is used to connect the first arc portion and the second arc portion, and the first connecting portion extends along the diameter direction of the arc portion 2211. The second connecting portion is used to connect the first arc portion and the third arc portion. The second connecting portion includes a first segment, a second segment, a third segment, a fourth segment, and a fifth segment connected in sequence. The first segment extends from the first arc portion along its diameter direction toward the third arc portion. The second segment extends from the first segment toward the third segment. Further, the second segment is perpendicular to the first segment. The third segment extends from the second segment along its diameter direction toward the fourth segment, and the extension direction is parallel to the extension direction of the first segment. The fourth segment extends from the third segment to the fifth segment, and the extension direction is parallel to the extension direction of the second segment. The fifth segment extends from the fourth segment along its diameter direction toward the third arc portion. The extension direction of the fifth segment is parallel to the extension directions of the first segment and the third segment. The first, second, and third sections are located between the positive and negative electrodes, filling part of the gap between them, increasing the heating area, and facilitating rapid heating.

[0047] In other embodiments, a first connecting portion is used to connect a first arcuate portion and a second arcuate portion, and the first connecting portion extends along the diametrical direction of the arcuate portion 2211. A second connecting portion is used to connect the first arcuate portion and a third arcuate portion, and the second connecting portion extends along the diametrical direction of the arcuate portion 2211. The extending direction of the second connecting portion is parallel to the extending direction of the first connecting portion.

[0048] In this embodiment, the ring width of the arc portion 2211 is 4.5 mm, the distance between two adjacent arc portions 2211 is 2.5 mm, and the thickness of the arc portion 2211 is 0.7 mm. This configuration enables a uniform current density distribution.

[0049] In summary, the electrode film layer 22 of this invention is completely embedded and sealed between the first ceramic layer 21 and the second ceramic layer 23, achieving complete isolation from the external environment and effectively preventing electrode oxidation. This solves the problems of traditional surface-printed electrodes being easily damaged by mechanical scratches, corroded by etching gases in the process environment (such as halogen gases in semiconductor processes), and contaminated by solder or other pollutants. The electrode film layer 22 is located inside the heating body 2, bringing the heat source closer to the heated workpiece (such as a wafer), reducing thermal resistance, and achieving faster thermal response and higher heating efficiency. Furthermore, the symmetrical sandwich structure of "first ceramic layer 21 - electrode film layer 22 - second ceramic layer 23" ensures that the coefficient of thermal expansion (CTE) of the materials on both sides of the electrode film layer 22 (heating element) is completely symmetrical. During thermal cycling, the generated thermal stress can be effectively offset by the symmetrical ceramic layers on both sides, greatly improving the thermal stress distribution and avoiding ceramic warping or cracking caused by stress concentration. This ensures high flatness and excellent thermal uniformity (±1°C or even better) of the heating surface, meeting the stringent requirements of high-end semiconductor manufacturing processes. Finally, the first ceramic layer 21, the electrode film layer 22, and the second ceramic layer 23 are laminated together to form an integral structure, eliminating the risk of delamination between different material interfaces due to adhesive aging. Furthermore, this integrated, dense structure exhibits higher mechanical strength and structural rigidity.

[0050] The above embodiments are only used to illustrate the technical solutions of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the spirit and scope of the technical solutions of this utility model.

Claims

1. A ceramic heater characterized by, include: Base (1); The heating body (2) is located below the base (1) and has a symmetrical ceramic sandwich structure; The symmetrical ceramic sandwich structure includes a first ceramic layer (21), an electrode film layer (22), and a second ceramic layer (23) stacked sequentially along the height; wherein the electrode film layer (22) is embedded between the first ceramic layer (21) and the second ceramic layer (23), and the second ceramic layer (23) is laminated with the first ceramic layer (21) to form an integral structure.

2. The ceramic heater of claim 1, wherein, Electrode paste is printed on the first ceramic layer (21) to form the electrode film layer (22).

3. The ceramic heater of claim 2, wherein, The electrode film layer (22) is provided with an electrode body (221), the electrode body (221) having a plurality of concentric arc portions (2211) and a plurality of connecting portions (2212) for connecting the arc portions (2211).

4. The ceramic heater of claim 3, wherein, The creepage distance between the two ends of the electrode body (221) is ≥10mm. The two ends of the electrode body (221) are a positive terminal and a negative terminal, respectively, for connecting to a power source.

5. The ceramic heater of claim 3, wherein, The electrode body (221) is a molybdenum electrode.

6. The ceramic heater of claim 3, wherein, The arc portion (2211) has a ring width of 4.5 mm, the distance between two adjacent arc portions (2211) is 2.5 mm, and the thickness of the arc portion (2211) is 0.7 mm.

7. The ceramic heater of claim 1, wherein, The base (1) and the heating body (2) are annular. The base (1) includes a first base (11) and a second base (12) arranged vertically. The second base (12) abuts against the heating body (2). The first base (11) has a first annular groove (111) on the side facing the second base (12), and the second base (12) has a second annular groove (121) on the side facing the first base (11). The first annular groove (111) and the second annular groove (121) are arranged opposite to each other and together form a closed cooling channel (13). The first base (11) has an inlet (112) and an outlet (113) communicating with the cooling channel (13).

8. The ceramic heater of claim 4, wherein, The base (1) is provided with a conductive component (14), and the conductive component (14) is provided with a conductive element (141) electrically connected to the electrode body (221). The base (1) also includes a first base (11) and a second base (12) arranged vertically. The first base (11) and the second base (12) are provided with installation spaces for the conductive element (141) to pass through at the positive and negative positions of the electrode film layer (22). The conductive element (141) is installed in the installation space by means of a ceramic gasket (142) and abuts against the electrode film layer (22).

9. The ceramic heater of claim 8, wherein, The conductive component (14) further includes a semi-circular gasket (143) and a retaining ring (144). The conductive element (141) is placed inside the ceramic gasket (142), and the retaining ring (144) is engaged with the conductive element (141). The semi-circular gasket (143) is fixedly connected to the base (1), and the semi-circular gasket (143) covers the retaining ring (144).

10. The ceramic heater of claim 9, wherein, There is a distance between the bottom end of the ceramic gasket (142) and the bottom of the second base (12), and the bottom end of the ceramic gasket (142) and the mounting space are filled with fixing adhesive.

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