Wafer heating device

Abstract

The application discloses a wafer heating device, which comprises a base, a first heater and a second heater arranged on the base, and a side reflection screen surrounding the base. The second heater is made of a material different from that of the first heater, and the second heater is a non-metallic heater. The second heater separates the first heater from the side reflection screen. The innovative three-circle heterogeneous heater design effectively solves the problems of easy deformation, short service life and high cost of the metal heater in the prior art at high temperature. The outer heater is made of graphite material, which significantly inhibits the outward deformation and separates the middle heater inside from the side reflection screen outside, thereby avoiding the risk of arc discharge between the heater and the side reflection screen due to the outward deformation of the heater.

Description

Technical Field

[0001] This invention relates to the field of semiconductor processing and manufacturing technology, and more specifically, to a wafer heating device. Background Technology

[0002] Semiconductor materials, as the foundation of the semiconductor and microelectronics industries, have undergone tremendous development through continuous upgrades and evolution. Metal-Organic Chemical Vapor Deposition (MOCVD), currently the most important semiconductor thin film growth process in semiconductor material manufacturing, essentially involves a gas-phase chemical reaction where metal-organic compounds react with other gases on a heated wafer surface, ultimately depositing a uniform and dense thin film. In semiconductor processing, the wafer heating device is one of the core subsystems, its core function being to provide a precise, uniform, and stable temperature environment for the wafer as a substrate. Whether it's the decomposition of the metal-organic source, the rate of chemical reactions on the substrate surface, or crystal nucleation and growth, all are highly dependent on the precise control of the substrate temperature.

[0003] Existing wafer heating devices typically use materials such as rhenium and tungsten as heaters. However, when used in prolonged high-temperature environments, these heaters are prone to deformation and outward expansion. In some cases, deformation can even cause arcing when the heater contacts the outer molybdenum ring, triggering an electric arc discharge that can crash the entire system, resulting in significant product and hardware losses. Furthermore, because the heaters are made of rhenium, repairs are expensive, and even after repair, their lifespan is quite limited, leading to high operating and maintenance costs. Deformation of the heater's outer ring also alters the temperature field, affecting temperature control in the process and causing defects in the semiconductor wafers, thus reducing product yield.

[0004] The aim is to further improve the wafer heating device, reduce equipment costs, and enhance the stability and uniformity of the temperature field. Summary of the Invention

[0005] The purpose of this invention is to provide a wafer heating device that effectively solves the problems of easy deformation, short lifespan, and high cost of existing metal heaters at high temperatures through an innovative three-ring heterogeneous heater design. The outer ring heater is made of graphite, which significantly suppresses outward deformation due to its high-temperature stability and isolates the inner middle ring heater from the outer side reflector, avoiding the risk of arc discharge and system downtime caused by heater deformation and outward expansion with the side reflector.

[0006] The present invention provides a wafer heating device, comprising: a base; a first heater and a second heater, respectively disposed on the base; a side reflector screen surrounding the base; wherein the second heater is made of a different material than the first heater, the second heater is a non-metallic heater, and the second heater separates the first heater from the side reflector screen.

[0007] Optionally, the first heater is made of tungsten or rhenium, and the second heater is made of graphite.

[0008] Optionally, it also includes a base plate located below the base, the base being connected to the base plate via mounting columns, the base plate being larger than the base, and the side reflector being located on the base plate.

[0009] Optionally, it also includes a pivot located in the middle region of the base, the top of the pivot forming a third heater located inside the first heater.

[0010] Optionally, a bottom reflector screen is also provided below the base, and the bottom reflector screen is installed between the base plate and the base via a mounting column.

[0011] Optionally, the base plate is further provided with a support column, one end of which extends from the lower surface of the base plate to serve as a support foot.

[0012] Optionally, a side screen connecting block is also provided on the base plate. The side screen connecting block is located on the upper surface of the base plate and is connected to the support column. The side reflective screen is connected to the base plate through the side screen connecting block, and the base plate connecting column is located on the outside of the side reflective screen.

[0013] Optionally, the side reflective screens include multiple side reflective screens, and the side screen connecting block is further provided with a first clamping block, which separates adjacent side reflective screens.

[0014] Optionally, the bottom reflector screen includes multiple screens, and adjacent bottom reflectors screens are separated by a second clamping block disposed on the mounting post.

[0015] The aforementioned wafer heating device further includes: an isolation ring located between the base and the bottom plate, the isolation ring surrounding the rotating shaft and isolating the inner ring from other areas; and an inner ring heating element for heating the rotating shaft, the inner ring heating element being fixed inside the isolation ring by a bracket.

[0016] The wafer heating device provided in this invention, through its multi-ring heterogeneous heater design, effectively improves upon the problems of high cost and operation and maintenance expenses caused by the easy deformation and short lifespan of rhenium / tungsten heaters in existing technologies at high temperatures. Furthermore, the heating device also incorporates side reflectors on the sides of the heaters to limit heat transfer to the surrounding sidewalls, reducing heat loss and maintaining a stable overall temperature field at high temperatures. By using graphite for the outer ring heaters, this invention effectively avoids the risk of arc discharge and system downtime caused by heater deformation and proximity to the side reflectors, while also reducing equipment maintenance costs. The middle and inner ring heaters can also retain metal materials (tungsten / rhenium) to ensure high-temperature corrosion resistance. The combination of independent temperature control for each ring and the multi-layered reflector structure on the sides and bottom significantly improves the uniformity of the wafer temperature field on the heating device. In addition, the composite design of graphite and metal balances the deformation resistance of the outer ring with the high-precision temperature control requirements of the inner ring, making it particularly suitable for semiconductor epitaxial processes with stringent requirements for temperature uniformity and corrosion resistance.

[0017] The wafer heating device provided in this invention achieves efficient heat utilization and loss suppression through a multi-layer reflective screen design, reducing energy waste. The introduction of the outer ring graphite heater effectively isolates the middle ring from the side reflective screens, preventing downtime caused by arc discharge between the metal heater and the reflective screens, thus reducing downtime for maintenance. The temperature control system, combined with feedback from multiple temperature sensors, can adjust the power output of the three rings in real time, improving the temperature field, controlling the temperature difference between the edge and center of the temperature field, and enhancing the uniformity of the wafer epitaxial film thickness and device yield. Attached Figure Description

[0018] The above and other objects, features and advantages of the present invention will become clearer from the following description of embodiments of the invention with reference to the accompanying drawings.

[0019] Figure 1 A top view of a wafer heating apparatus according to an embodiment of the present invention is shown;

[0020] Figure 2 A first cross-sectional view of a wafer heating apparatus according to an embodiment of the present invention is shown;

[0021] Figure 3 A second cross-sectional view of the wafer heating apparatus according to an embodiment of the present invention is shown;

[0022] Figure 4 A third cross-sectional view of the wafer heating apparatus according to an embodiment of the present invention is shown;

[0023] Figure 5 A bottom view of a wafer heating apparatus according to an embodiment of the present invention is shown;

[0024] Figure 6A control flowchart of a wafer heating device according to an embodiment of the present invention is shown. Detailed Implementation

[0025] The invention will now be described in more detail with reference to the accompanying drawings. In the various drawings, the same elements are indicated by similar reference numerals. For clarity, the various parts in the drawings are not drawn to scale. Furthermore, some well-known parts may not be shown.

[0026] It should be understood that when describing the structure of a component, when referring to a layer or region as being "above" or "on top of" another layer or region, it can mean that it is directly above the other layer or region, or that it contains other layers or regions between it and the other layer or region. Furthermore, if the component is flipped over, that layer or region will be located "below" or "under" the other layer or region.

[0027] To describe a situation where it is located directly on another layer or another area, this article will use the expressions "directly on top of" or "on and adjacent to".

[0028] Many specific details of the invention, such as the structure, materials, dimensions, processing methods, and techniques of the components, are described below to provide a clearer understanding of the invention. However, as those skilled in the art will understand, the invention may be implemented without following these specific details.

[0029] This invention can be presented in various forms, some of which will be described below.

[0030] Figure 1A top view of a wafer heating device according to an embodiment of the present invention is shown. This wafer heating device, for example, is used to heat a wafer located thereon. The wafer heating device includes: a base 100, an inner ring heater 110, a middle ring heater 120, an outer ring heater 130, a base plate 200, a base plate support column 210, a side screen connecting block 220, and a side reflector screen 230. The inner ring heater 110 is located at the center. The middle ring heater 120 and the outer ring heater 130 are, for example, both located on the base 100. The outer ring heater 130 is, for example, annular, surrounding the middle ring heater 120 and separating the middle ring heater 120 from the side reflector screen 230. The middle ring heater 120 includes, for example, multiple arc-shaped bends and corners to fully fill the portion between the inner ring heater 110 and the outer ring heater 130 in the top view, thereby increasing the area to improve the heating effect and temperature uniformity. Specifically, the inner ring heater 110 is made of rhenium, for example; the middle ring heater 120 is made of tungsten or rhenium, for example; the outer ring heater 130 is made of graphite, for example; and the base 100 is made of boron nitride, for example. The base 100 is provided with a first fixing plate 121 and a second fixing plate 131. The middle ring heater 120 is positioned and fixed to the base 100 via the first fixing plate 121, and the outer ring heater 130 is positioned and fixed to the base 100 via the second fixing plate 131. The second fixing plate 131 also has a partially protruding structure, which can be located, for example, in the gap between the middle ring heater 120 and the outer ring heater 130 to ensure the distance between them. The size of the base 100 is, for example, smaller than the size of the base plate 200. The base plate 200 is located below the base 100. A side reflector 230 is provided on the base plate 200, surrounding the base 100, the inner ring heater 110, the middle ring heater 120, and the outer ring heater 130. This side reflector 230 can significantly reduce heat loss from the sides, improve the uniformity of the temperature of the entire surface of the heating device, and reduce the problem that the temperature of the outer ring of the heating device is significantly lower than that of the inner and middle rings due to faster heat dissipation at the edges. The side reflector 230 is, for example, made of molybdenum. The side reflector 230 is connected by a side screen connecting block. 220 is connected to the base plate 200. Specifically, a base plate support column 210 is provided on the edge area of ​​the base plate 200. One end of the base plate support column 210 passes through the base plate 200, extends from the lower surface of the base plate 200, and serves as a support for the base plate 200. The other end of the base plate support column 210 is located on the upper surface of the base plate 200 and is connected to the side screen connecting block 220. The side screen connecting block 220 extends radially inward from the base plate support column 210 along the base plate 200. The side screen connecting block 220 and the base plate support column 210 are connected, for example, by bolts. The side reflector 230 is located, for example, inside the base plate support column 210. The two ends of the middle ring heater 120 are connected to the corresponding middle ring connecting column by bolts, for example. Similarly, the two ends of the outer ring heater 130 are also connected to the corresponding outer ring connecting column by bolts, for example. The temperature control system adjusts and controls the temperature of the heating device through the connecting columns.This wafer heating device can be used in MOCVD processes.

[0031] exist Figure 1 In the top view, by cutting along section line AA of the wafer heating device, the following can be obtained: Figure 2 The first cross-sectional view shown; cutting along the BB section line, we can obtain the following... Figure 3 The second cross-sectional view shown; by cutting along the CC section line, the following can be obtained: Figure 4 The third cross-sectional view shown here; the cross-sectional view can more clearly show the structure between the base 100 and the base plate 200, the longitudinal positional relationship, and the shape and positional relationship of each component structure in the wafer heating device.

[0032] See Figure 2 As shown in the first cross-sectional view, the wafer heating device also includes a rotating shaft 300 in the middle. The rotating shaft 300 is made of, for example, molybdenum. The top of the rotating shaft 300 is, for example, an inner ring heater 110. An isolation ring 112 is also provided in the middle region between the base 100 and the base plate 200. The isolation ring 112 surrounds the rotating shaft 300, and an inner ring heater 111 is also provided inside the isolation ring 112. The inner ring heater 111 heats the rotating shaft 300, thereby raising the temperature of the inner ring heater 110 at the top of the rotating shaft 300. Furthermore, an inner ring temperature sensor 113 is also provided on the base plate 200. The inner ring temperature sensor 113 extends from the lower surface of the base plate 200 into the isolation ring 112 to detect the temperature of the inner ring heater 110 inside the isolation ring 112. Figure 2 It can also be seen that an outer ring connecting rod 132 is provided behind the rotating shaft 300. The two outer ring connecting rods 132 are connected to the two ends of the outer ring heater 130, for example. By changing the voltage and / or current connected to the outer ring connecting rods 132, the temperature of the outer ring heater 130 is changed. The middle ring heater 120 is similar to the outer ring heater 130, and will not be described in detail.

[0033] The wafer heating device also includes a support column 210, which is connected to the base plate 200. The lower end of the support column 210 serves as a support foot to support the base plate 200, and the upper end of the support column 210 passes through the base plate 200 and extends out from the upper surface of the base plate 200. A side screen connecting block 220 is also provided on the upper surface of the base plate 200. The side screen connecting block 220 is connected to the support column 210. For example, the support column 210 is located outside the side screen connecting block 220. The side reflective screen 230 is connected to the base plate 200 through the side screen connecting block 220. The side reflective screen 230 is arranged around the base 100. Specifically, the side reflective screen 230 includes, for example, four layers. The side screen connecting block 220 also includes a first clamping block 231, which separates two adjacent layers of side reflective screen 230. The side reflective screen 230 restricts the transfer of heat to the surrounding side walls, further reducing heat loss and maintaining the stability of the overall temperature field of the heating device at high temperatures.

[0034] The upper surface of the base plate 200 is also provided with a mounting post 170, which is located in the inner area of ​​the side reflector 230, below the base 100. The base 100 is connected to the base plate 200 through the mounting post 170. The base plate 200 is, for example, made of heat-resistant stainless steel, and the base 100 is, for example, made of boron nitride. Below the base 100, a first bottom reflector 150 and a second bottom reflector 160 are also provided. The first bottom reflector 150 and the second bottom reflector 160 are respectively set at different heights of the mounting post 170. The first bottom reflector 150 is located above the second bottom reflector 160. Specifically, the second bottom reflector 160 includes, for example, four layers. That is, below the base 100, there are a first bottom reflector 150 and four layers of second bottom reflectors 160, totaling five layers of bottom reflectors. This can effectively prevent heat from being transferred downwards and wasting heat, and reflect the heat transferred downwards back.

[0035] See Figure 3 As shown in the second cross-sectional view, the inner ring heating element 111 is supported and fixed in the isolation ring 112 by the bracket 114, and is fixedly connected to the lower surface of the base plate 200 by the fixing plate 115. At the same time, the inner ring heating element 111 is electrically connected to the inner ring connecting rod 116 by the bracket 114. In order to set multiple bottom reflectors at different heights of the mounting column 170, a second clamping block 171 is also provided on the mounting column 170. By setting different second clamping blocks 171, the base 100 is separated from the first bottom reflector 150, the first bottom reflector 150 is separated from the second bottom reflector 160, and adjacent second bottom reflectors 160 are separated.

[0036] See Figure 4As shown in the third cross-sectional view, the two ends of the middle ring heater 120 are connected to the middle ring connecting rod 122 by bolts 123, for example. An insulating sleeve 140 is also provided on the outside of the middle ring connecting rod 122, for example, the insulating sleeve 140 is made of quartz. Correspondingly, an insulating sleeve 140 is also provided on the outside of the outer ring connecting rod 132 to prevent abnormal conduction of the connecting rod when passing through the bottom reflector screen.

[0037] Figure 5 A bottom view of a wafer heating apparatus according to an embodiment of the present invention is shown; Figure 5 The base plate 200 is visible, and the base plate 200 is respectively equipped with an inner ring temperature sensor 113, a middle ring temperature sensor 124, and an outer ring temperature sensor 133 at corresponding positions to detect the actual temperature at the inner ring heater 110, the middle ring heater 120, and the outer ring heater 130, respectively. The temperature of each ring heater is adjusted according to the data detected by the sensors. The two ends of the inner ring heating element 111 of the inner ring heater 110 are electrically connected to the inner ring connecting rod 116 through the bracket 114; the two ends of the middle ring heater 120 are electrically connected to the middle ring connecting rod 122; and the two ends of the outer ring heater 130 are electrically connected to the outer ring connecting rod 132. By changing the voltage and / or current connected to the corresponding connecting rod, the heating condition of the corresponding heater is changed, thereby changing the temperature at the corresponding position.

[0038] Figure 6 A control flowchart of a wafer heating device according to an embodiment of the present invention is shown. The control flow of the heating device includes the following steps:

[0039] In step S10, the temperature control unit issues a command signal; specifically, the wafer heating device also includes a control system to regulate the specific heating temperature, temperature curve and overall temperature field of the wafer heating device; the temperature control unit of the control system generates and sends a corresponding command signal based on preset temperature parameter information and / or temperature data obtained by the temperature sensor.

[0040] In step S20, the power supply unit generates a corresponding power signal; specifically, the power supply unit of the control system generates a corresponding power supply current according to the command signal. The power supply current has a specific current value and voltage value, and the power of each heater is changed by changing the current value and / or voltage value of the power supply current.

[0041] In step S30, each ring heater heats up; specifically, the power supply unit provides the corresponding power supply current to the inner ring heater 110, the middle ring heater 120 and the outer ring heater 130 respectively, and each ring heater heats up.

[0042] In step S40, the temperature sensor acquires temperature data. Specifically, the wafer heating device is equipped with three temperature sensors at different locations to detect the inner ring temperature, middle ring temperature, and outer ring temperature respectively, thereby obtaining the actual temperature of different regions of the temperature field of the heating device. The temperature data is then fed back to the temperature control unit. The temperature control unit adjusts the command signal based on the difference between the detected temperature data and the target temperature, thereby changing the heating state of each ring heater so that the actual temperature in the temperature field approaches the target temperature.

[0043] The wafer heating device provided in this invention, through its multi-ring heterogeneous heater design, effectively improves upon the problems of high cost and operation and maintenance expenses caused by the easy deformation and short lifespan of rhenium / tungsten heaters in existing technologies at high temperatures. Furthermore, the heating device also incorporates side reflectors on the sides of the heaters to limit heat transfer to the surrounding sidewalls, reducing heat loss and maintaining a stable overall temperature field at high temperatures. By using graphite for the outer ring heaters, this invention effectively avoids the risk of arc discharge and system downtime caused by heater deformation and proximity to the side reflectors, while also reducing equipment maintenance costs. The middle and inner ring heaters can also retain metal materials (tungsten / rhenium) to ensure high-temperature corrosion resistance. The combination of independent temperature control for each ring and the multi-layered reflector structure on the sides and bottom significantly improves the uniformity of the wafer temperature field on the heating device. In addition, the composite design of graphite and metal balances the deformation resistance of the outer ring with the high-precision temperature control requirements of the inner ring, making it particularly suitable for semiconductor epitaxial processes with stringent requirements for temperature uniformity and corrosion resistance.

[0044] The wafer heating device provided in this invention achieves efficient heat utilization and loss suppression through a multi-layer reflective screen design, reducing energy waste. The introduction of the outer ring graphite heater effectively isolates the middle ring from the side reflective screens, preventing downtime caused by arc discharge between the metal heater and the reflective screens, thus reducing downtime for maintenance. The temperature control system, combined with feedback from multiple temperature sensors, can adjust the power output of the three rings in real time, improving the temperature field, controlling the temperature difference between the edge and center of the temperature field, and enhancing the uniformity of the wafer epitaxial film thickness and device yield.

[0045] The above description does not provide detailed technical specifications regarding the composition and processing methods of each component. However, those skilled in the art should understand that heaters and support columns of the desired shapes can be formed using various technical means. Furthermore, although each component and its variations have been described above, this does not mean that the variations in the various embodiments cannot be advantageously combined.

[0046] The embodiments of the present invention have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of the invention. The scope of the invention is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of the invention, and all such substitutions and modifications should fall within the scope of the invention.

Claims

1. A wafer heating device, characterized in that, include: Base; The first heater and the second heater are respectively disposed on the base; A side reflective screen, the side reflective screen surrounding the base; A base plate is located below the base, and the base is connected to the base plate via mounting columns. The size of the base plate is larger than the size of the base, and the side reflector is located on the base plate. The second heater is made of a different material than the first heater; the second heater is a non-metallic heater, and it separates the first heater from the side reflector.

2. The wafer heating apparatus according to claim 1, characterized in that, The first heater is made of tungsten or rhenium, and the second heater is made of graphite.

3. The wafer heating apparatus according to claim 1, characterized in that, It also includes a rotating shaft located in the middle region of the base, the top of which forms a third heater located inside the first heater.

4. The wafer heating apparatus according to claim 1, characterized in that, A bottom reflector is also provided below the base, and the bottom reflector is installed between the base plate and the base via mounting columns.

5. The wafer heating apparatus according to claim 4, characterized in that, The base plate is also provided with a support column, one end of which extends from the lower surface of the base plate to serve as a support foot.

6. The wafer heating apparatus according to claim 5, characterized in that, A side screen connecting block is also provided on the base plate. The side screen connecting block is located on the upper surface of the base plate and is connected to the support column. The side reflective screen is connected to the base plate through the side screen connecting block, and the base plate connecting column is located on the outside of the side reflective screen.

7. The wafer heating apparatus according to claim 6, characterized in that, The side reflective screens include multiple ones, and the side screen connecting block is further provided with a first clamping block, which separates adjacent side reflective screens.

8. The wafer heating apparatus according to claim 4, characterized in that, The bottom reflector screen includes multiple screens, and adjacent bottom reflector screens are separated by a second clamping block disposed on the mounting post.

9. The wafer heating apparatus according to claim 3, characterized in that, Also includes: An isolation ring is located between the base and the bottom plate, and the isolation ring is arranged around the rotating shaft to isolate the inner ring from other areas. An inner ring heating element is used to heat the rotating shaft, and the inner ring heating element is fixed inside the isolation ring by a bracket.

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