Uniform sintering equipment for large-size ultrathin ceramics

Abstract

The utility model is suitable for the technical field of ceramic sintering, and provides uniform sintering equipment for large-size ultrathin ceramic. The large-size ultra-thin ceramic uniform sintering equipment comprises a heating assembly and a sintering assembly, wherein the heating assembly is used for uniformly radiating heat in the heating assembly; the at least one burning tray is arranged in the heating assembly; the upper surface of the burning tray is a plane and is used for bearing workpieces, and the center thickness of the lower surface is smaller than the edge thickness. The edge of the burning tray is thick, the middle of the burning tray is thin, the temperature correspondence of the burning tray is improved, and the temperature difference on the horizontal plane of a workpiece is reduced.

Description

TECHNICAL FIELD

[0001] The utility model belongs to ceramic sintering technical field especially relates to a large size ultra -thin ceramic even sintering equipment. BACKGROUND

[0002] In the semiconductor production process, the transfer of chip needs to use the components such as boat, chuck, suction cup, this kind of spare part is usually thin-walled part, such as suction cup thickness is about 5mm, this kind of spare part is influenced by the temperature difference of plane in the process of firing, and easily appears warping deformation. With the development of industrial technology, wafer size develops from 6 inches, 8 inches to 12 inches, the size of existing suction cup and other components will become larger, the temperature difference requirement of plane in the sintering process is higher, and the product qualified rate is lower. For example, a workpiece with a diameter greater than 400mm (thickness of 5mm), the horizontal temperature difference should not exceed 3 ℃.

[0003] The previous ceramic sintering equipment is usually vertical structure, and the tubular cage type heating body is heated after power supply, and the components are heated in the form of radiation. Because the radiation area of the heating body is small, the components cannot be uniformly radiated, and the temperature difference will be formed on the horizontal plane, which is not conducive to production. SUMMARY

[0004] The purpose of the embodiment of the utility model is to provide a large size ultra -thin ceramic even sintering equipment, and aim at solving the problem of uneven sintering of large size ultra -thin ceramic.

[0005] The embodiment of the utility model is realized as follows, a large size ultra -thin ceramic even sintering equipment, the large size ultra -thin ceramic even sintering equipment includes:

[0006] Heating assembly, for uniform radiation of heat in the inside;

[0007] At least one sintering support, is arranged in the inside of the heating assembly;The upper surface of the sintering support is a plane, for carrying workpiece, and the thickness of the center of the lower surface is less than the edge thickness.

[0008] Further, the heating assembly includes:

[0009] Crucible, internally provided with the sintering support.

[0010] A plurality of heating bodies, are circumferentially arranged around the circumference of the crucible.

[0011] Further, the top of the crucible is provided with an upper cover, and the bottom is provided with a lower cover;The crucible is provided with a first airflow channel in the circumferential direction, the lower cover is provided with a first air vent, the upper cover is provided with a second air vent, and a radial second airflow channel is arranged in the inside;The second air vent is communicated with the second airflow channel, the second airflow channel is communicated with the first airflow channel, and the first airflow channel is communicated with the first air vent.

[0012] Further, the large-size ultra-thin ceramic uniform sintering equipment further comprises a heat preservation layer and a furnace shell, the heat preservation layer wraps the heating assembly, the furnace shell wraps the heat preservation layer, and the first air vent and the second air vent pass through the heat preservation layer and the furnace shell.

[0013] Further, the large-size ultra-thin ceramic uniform sintering equipment further comprises a vacuum system for extracting air between the heat preservation layer and the furnace shell.

[0014] Further, the crucible material is an isotropic material.

[0015] Further, the profile of the lower surface of the supporting plate is a natural logarithmic function curve.

[0016] Further, the large-size ultra-thin ceramic uniform sintering equipment further comprises a control system, the outer surface of the crucible and the center position of the workpiece are provided with thermocouples; the control system is used for controlling the heat generation of the heating body, and the temperature difference between the surface of the crucible and the center of the workpiece, the temperature difference of the crucible itself, the designed temperature difference between the crucible and the supporting plate, and the temperature difference between the heating body and the outer surface of the crucible are controlled within a preset range.

[0017] The large-size ultra-thin ceramic uniform sintering equipment provided by the embodiment of the utility model, workpiece is placed on supporting plate, heat is transferred from outer diameter to center in sintering process, according to thermodynamic law, there is necessarily high external temperature and low internal temperature in the process of heating of supporting plate, in the process of cooling, there is necessarily high internal temperature and low external temperature, this phenomenon can cause deviation of workpiece temperature uniformity, and lead to sintering failure of product. Therefore, the edge of the supporting plate of the utility model is thick, and the middle is thin, the temperature correspondence of the supporting plate is improved, and the temperature difference on the horizontal plane of the workpiece is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a sectional view of the large-size ultra-thin ceramic uniform sintering equipment in the first embodiment;

[0019] Figure 2 It is a sectional view of the large-size ultra-thin ceramic uniform sintering equipment in the first embodiment; Figure 1 It is a sectional view of the large-size ultra-thin ceramic uniform sintering equipment in the first embodiment;

[0020] Figure 3 It is a sectional view of the large-size ultra-thin ceramic uniform sintering equipment in the first embodiment;

[0021] Figure 4 It is a sectional view of the large-size ultra-thin ceramic uniform sintering equipment in the first embodiment;

[0022] Figure 5 It is a sectional view of the large-size ultra-thin ceramic uniform sintering equipment in the first embodiment;

[0023] Figure 6Structure diagram of workpiece and supporting plate in the first embodiment;

[0024] Figure 7 Flow chart of large-size ultra-thin ceramic uniform sintering process in the second embodiment.

[0025] Reference signs:

[0026] 100, heating assembly; 110, crucible; 120, heating body; 130, upper cover; 140, lower cover; 150, first air flow channel; 160, first air vent; 170, second air vent; 180, second air flow channel;

[0027] 200, supporting plate;

[0028] 300, heat preservation layer;

[0029] 400, furnace shell;

[0030] 500, vacuum system;

[0031] 600, thermocouple;

[0032] 700, workpiece. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the utility model more clearly understood, the utility model is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the utility model, and are not used to limit the utility model.

[0034] It can be understood that the terms "first", "second" and the like used herein can be used to describe various elements, but unless specifically stated, these elements are not limited by these terms. These terms are only used to distinguish the first element from another element.

[0035] As shown in the first embodiment, a large-size ultra-thin ceramic uniform sintering equipment is given, which comprises: Figure 1

[0036] A heating assembly 100 is used to radiate heat uniformly inside;

[0037] At least one supporting plate 200 is arranged inside the heating assembly 100; the upper surface of the supporting plate 200 is a plane, used to carry a workpiece 700, and the center thickness of the lower surface is less than the edge thickness.

[0038] ​In the embodiment, it should be noted that "large size" and "ultra-thin" are relative technical terms, for example, a workpiece with a diameter greater than 400 mm and a thickness of 5 mm can be referred to as a large-size ultra-thin workpiece. The embodiment can be applied to precision sintering of large-size ultra-thin ceramics, which are mainly used in precision ceramics in the semiconductor manufacturing process, such as electrostatic chucks, wafer chucks, and other fields with strict deformation requirements in the ceramic sintering process. It can also be used for the production of large-size ultra-thin alumina, silicon carbide, silicon nitride, and composite ceramics to obtain products with small deformation, high flatness, and uniform density for subsequent process production.

[0039] In the embodiment, the number of the sintering trays 200 is not less than 1; when there are multiple sintering trays 200, the sintering trays 200 are stacked in multiple layers, and each sintering tray 200 can place a workpiece 700. The sintering tray 200 can be made of isotropic high-thermal-conductivity materials (graphite, silicon carbide, aluminum nitride, etc.) and designed with a specific configuration to support the sintered workpiece 700 and enable rapid heat transfer.

[0040] The workpiece 700 in the embodiment is placed on the sintering tray 200, and heat is transferred from the outer diameter to the center. According to the laws of thermodynamics, during the heating process, the sintering tray 200 will inevitably have a higher temperature on the outside and a lower temperature on the inside. During the cooling process, the sintering tray 200 will inevitably have a higher temperature on the inside and a lower temperature on the outside. This phenomenon will cause deviations in the temperature uniformity of the workpiece 700, leading to sintering failure of the product. Therefore, the thickness of the sintering tray 200 at different positions is optimized in the embodiment, and the overall shape is thin in the middle and thick at the edges, which improves the temperature responsiveness of the sintering tray 200 and the thermal conductivity of the sintering tray 200, thereby reducing the temperature difference on the horizontal plane of the workpiece 700.

[0041] In the first embodiment, as shown in Figure 2 and 3 , the structure of the heating assembly 100 is specifically optimized, and the heating assembly 100 includes:

[0042] The crucible 110 is internally provided with the sintering tray 200.

[0043] A plurality of heating bodies 120 are circumferentially arranged around the crucible 110.

[0044] In this optimization scheme, the heating body 120 is columnar with a diameter not less than 30 mm, the spacing between the heating bodies 120 is not more than 150 mm, and the spacing between the heating body 120 and the crucible 110 is not less than 50 mm, so that the heat generated by the heating body 120 is radiated to the surface of the crucible 110, and the temperature difference between the outer surface of the crucible 110 body and the heating body 120 is not more than 0.5°C. The heating body 120 is made of high-purity graphite and has a tubular cage structure or a cylindrical structure.

[0045] The crucible 110 is made of high thermal conductive graphite material, adopts thin wall structure, and the thickness is not greater than 30 mm. In order to avoid that the heating body 120 directly radiates the surface of the workpiece 700, causing the temperature difference of the workpiece 700 to increase, a crucible 110 is added between the heating body 120 and the workpiece 700. The heat of the heating body 120 is first radiated to the crucible 110 and quickly transmitted, so that the temperature of the crucible 110 is uniform, the low-temperature-difference crucible 110 wraps the entire workpiece 700, and the thermal radiation can form uniform scattering, so that the workpiece 700 can be uniformly heated. In order to reduce the temperature non-uniformity caused by heat transfer in the crucible 110, the material of the crucible 110 should be isotropic material, such as isostatic pressing graphite. The thickness of the crucible 110 is determined according to the heat required when the heat or cooling process is maintained at a stable temperature difference (3℃) of the support plate 200, and the internal and external temperature difference is kept within 0.5℃ (the temperature can be adjusted according to the control progress). The thickness of the crucible 110 needs to be as low as possible under the condition of meeting the process conditions, and the maximum thickness is not more than 30 mm, so as to reduce the thermal inertia, improve the corresponding speed of the heating control temperature, and reduce the risk of temperature overshoot.

[0046] In the first embodiment, as shown in Figures 2-5 The top of the crucible 110 is provided with an upper cover 130, and the bottom is provided with a lower cover 140. The crucible 110 is provided with a first airflow channel 150 in the circumferential direction. The lower cover 140 is provided with a first air vent 160, and the upper cover 130 is provided with a second air vent 170 and an internal radiation-shaped second airflow channel 180. The second air vent 170 is connected to the second airflow channel 180, the second airflow channel 180 is connected to the first airflow channel 150, and the first airflow channel 150 is connected to the first air vent 160.

[0047] In the optimization scheme, the crucible 110 is made of isotropic material, and the thickness is designed according to the properties of the sintered workpiece 700 and the supporting plate 200. The first gas flow channel 150 parallel to the axis is arranged in the circumferential direction of the crucible 110, and the upper cover 130 is arranged at the top, and the second vent 170 is arranged at the center of the upper cover 130. The upper cover 130 is provided with a second gas flow channel 180, which corresponds to the first gas flow channel 150 of the crucible 110. The size of the second gas flow channel 180 of the upper cover 130 is optimized according to numerical simulation, so that the flow rate of each hole is consistent. The lower cover 140 is arranged at the bottom of the crucible 110, and the first vent 160 is arranged on the lower cover 140, which corresponds to the first gas flow channel 150 of the crucible 110. The first gas flow channel 150 converges at the center position and then flows out through the pipeline. In the rapid cooling stage, the gas enters through the top second vent 170, then disperses into the interior of the crucible 110, and then flows out through the bottom; similarly, the gas can also enter through the bottom first vent 160, disperse into the interior of the crucible 110, and then flow out through the top. Through the fine design of the number of flow channels and the diameter of the holes, the temperature of the crucible 110 itself can be uniformly cooled on the same horizontal plane, thereby avoiding the influence of the external environment of the crucible 110 on the crucible 110, and adopting the temperature distribution which is not uniform, resulting in inconsistent temperature of the internal supporting plate 200.

[0048] In the first embodiment, as shown in Figure 1 , the structure of the large-size ultra-thin ceramic uniform sintering equipment is specifically optimized. The large-size ultra-thin ceramic uniform sintering equipment further comprises a heat preservation layer 300 and a furnace shell 400, the heat preservation layer 300 wraps the heating assembly 100, and the furnace shell 400 wraps the heat preservation layer 300. The first vent 160 and the second vent 170 pass through the heat preservation layer 300 and the furnace shell 400. The large-size ultra-thin ceramic uniform sintering equipment further comprises a vacuum system 500 for extracting air between the heat preservation layer 300 and the furnace shell 400.

[0049] In the optimization scheme, the heat preservation layer 300 is made of high-purity, low-thermal-conductivity carbon fiber heat preservation material. The furnace shell 400 is made of stainless steel and is used to build a closed environment required for production. The vacuum system 500 is composed of a mechanical pump, a booster pump, a diffusion pump, a maintenance pump (increased or decreased according to needs), and corresponding pipeline valves, and is used to build and maintain the vacuum environment of the equipment.

[0050] In the first embodiment, as shown in Figure 6As shown, the structure of the supporting tray 200 is particularly optimized. The profile of the lower surface of the supporting tray 200 is a natural logarithmic function curve. The method for determining the thickness of the outer circle of the supporting tray 200 is as follows: the amount of heat to be transferred is determined according to the requirement that the maximum temperature difference of the supporting tray 200 is not more than 3℃, the temperature difference between the supporting tray 200 and the crucible 110 is selected, and the outer circle area of the supporting tray 200 required for transferring the corresponding amount of heat is calculated according to the radiation law formula, and then the height thereof is determined.

[0051] In the optimization scheme, the upper surface of the supporting tray 200 is a plane for carrying the workpiece 700, and the lower surface is a structure with thin center and thick edge, the profile of which is similar to a natural logarithmic function curve and is related to the thermal conductivity, specific heat and density of the fired workpiece 700 and the supporting tray 200. Through design, the temperature difference between the center and the outer circle of the supporting tray 200 is not more than 3℃, and the thickness of the outer circle of the supporting tray 200 is determined according to radiation calculation.

[0052] In the first embodiment, the structure of the large-size ultra-thin ceramic uniform sintering equipment is particularly optimized. The large-size ultra-thin ceramic uniform sintering equipment further comprises a control system, and a thermocouple 600 is arranged at the outer surface of the crucible 110 and the center position of the workpiece 700; the control system is used for controlling the heat generation of the heating body 120, so that the temperature difference between the surface of the crucible 110 and the center of the workpiece 700, the temperature difference of the crucible 110 itself, the design temperature difference between the crucible 110 and the supporting tray 200, and the temperature difference between the heating body 120 and the outer surface of the crucible 110 are controlled within a preset range.

[0053] In the optimization scheme, the thermocouple 600 is arranged at the outer surface of the crucible 110 and the center position of the workpiece 700, and the control process needs to meet the following conditions: the temperature difference between the outer surface and the center of the crucible 110 is not more than the allowable temperature difference of the workpiece 700, the design temperature difference between the crucible 110 and the supporting tray 200 (determined by material performance and radiation heat transfer), and the temperature difference of the crucible 110 itself; not more than 3.5℃+the design temperature difference between the crucible 110 and the supporting tray 200; the temperature difference between the heating body 120 and the outer surface of the crucible 110 is determined; under the condition of radiation, the temperature rising rate is not more than 0.5℃ / min, and the amount of heat transferred is equal to the amount of heat required for maintaining the design temperature difference of the workpiece.

[0054] The optimization features of the above first embodiment can be combined in any manner. For the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present disclosure.

[0055] As Figure 7As shown in the second embodiment, a large-size ultra-thin ceramic uniform sintering process is proposed, which is applied to the large-size ultra-thin ceramic uniform sintering equipment in the first embodiment, and specifically includes the following steps S1-S4:

[0056] In step S1, the heat receiving plate 200 is selected according to the sintered product.

[0057] In this embodiment, the thermal conductivity, specific heat, density, and bottom profile shape of the heat receiving plate 200 can be selected, and through design, the temperature difference between the center and the outer circle of the heat receiving plate 200 is not more than 3℃.

[0058] In step S2, the air is extracted by the vacuum system 500, so that the heating assembly 100 is blocked by vacuum.

[0059] In this embodiment, the initial vacuum environment of the equipment is constructed by the vacuum system 500, and the vacuum environment during the process of the equipment is maintained by the maintenance pump.

[0060] In step S3, the temperature rising program is selected according to the characteristics of the workpiece 700 and the heat receiving plate 200, and the sintering is maintained.

[0061] In this embodiment, the corresponding sintering process program is selected, the temperature rising program is started to complete the temperature rising and sintering, at this time, the heat is transferred from the outside to the inside, and the temperature rising program needs to be selected according to the characteristics of the workpiece 700 and the heat receiving plate 200.

[0062] In step S4, after the sintering is completed, the air flow is selected to pass through the first air flow channel 150 of the crucible 110 in the heating assembly 100 from top to bottom or from bottom to top.

[0063] In this embodiment, according to the characteristics of the heat receiving plate 200, before 500℃, the corresponding temperature decreasing program is selected, and the system controls the temperature decreasing. After 500℃, the air flow is uniformly controlled into the channel of the crucible 110 to perform rapid cooling. The air flow direction is second air outlet 170, second air flow channel 180, first air flow channel 150 and first air inlet 160 in turn, and the air flow direction can also be in reverse order. Therefore, the heat receiving plate 200 structure design, temperature rising strategy and uniform cooling strategy of large-size ultra-thin ceramic uniform sintering in this embodiment are designed, the temperature difference on the horizontal plane of the workpiece is reduced, and the sintering quality is improved.

[0064] The above-described embodiments only express several implementation manners of the utility model, the description is more specific and detailed, but can not therefore be understood as the limitation of the utility model patent range. It should be pointed out that for ordinary skilled person in the art, without departing from the utility model concept, several deformations and improvements can be made, which belong to the protection range of the utility model. Therefore, the protection range of the utility model patent should be subject to the appended claims.

Claims

1. A large size ultra-thin ceramic uniform sintering apparatus, characterized in that, The large-size ultra-thin ceramic uniform sintering equipment comprises: a heating assembly for uniformly radiating heat inside; at least one sintering plate arranged inside the heating assembly; the upper surface of the sintering plate is flat for carrying a workpiece, and the central thickness of the lower surface is less than the edge thickness.

2. The apparatus for uniform sintering of large size ultra-thin ceramic according to claim 1, wherein, The heating assembly comprises: a crucible in which the sintering plate is arranged; a plurality of heating bodies arranged around the periphery of the crucible.

3. The apparatus for uniform sintering of large size ultra-thin ceramic according to claim 2, wherein, The top of the crucible is provided with an upper cover, and the bottom is provided with a lower cover; the crucible is provided with a first air flow channel in the circumferential direction, the lower cover is provided with a first air vent, the upper cover is provided with a second air vent, and the inside is provided with a radial second air flow channel; the second air vent communicates with the second air flow channel, the second air flow channel communicates with the first air flow channel, and the first air flow channel communicates with the first air vent.

4. The apparatus for uniform sintering of large size ultra-thin ceramic according to claim 3, wherein, The large-size ultra-thin ceramic uniform sintering equipment further comprises a heat preservation layer and a furnace shell, the heat preservation layer wraps the heating assembly, the furnace shell wraps the heat preservation layer, and the first air vent and the second air vent pass through the heat preservation layer and the furnace shell.

5. The apparatus for uniform sintering of large size ultra-thin ceramic according to claim 4, wherein, The large-size ultra-thin ceramic uniform sintering equipment further comprises a vacuum system for extracting air between the heat preservation layer and the furnace shell.

6. The apparatus for uniform sintering of large size ultra-thin ceramic according to claim 2, wherein, The material of the crucible is selected to be isotropic.

7. The apparatus according to claim 1, wherein The profile of the lower surface of the sintering plate is a natural logarithmic function curve.

8. The apparatus for uniform sintering of large size ultra-thin ceramic according to claim 2, wherein, The large-size ultra-thin ceramic uniform sintering equipment further comprises a control system, and the outer surface of the crucible and the center position of the workpiece are provided with thermocouples; the control system is used to control the heat generation of the heating bodies, and the temperature difference between the surface of the crucible and the center of the workpiece, the temperature difference of the crucible itself, the designed temperature difference between the crucible and the sintering plate, and the temperature difference between the heating bodies and the outer surface of the crucible are controlled within a preset range.

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