Wafer temperature uniformity control and automatic transfer integrated device in hot plate pumping process

Abstract

The utility model provides a kind of wafer temperature uniform control and automatic transfer integrated device in hot plate air extraction process, including disc-shaped cavity main body and automatic wafer transfer assembly, cavity main body top is plane structure, hot plate upper surface is perpendicular to the central axis of cavity main body, the sealing disc is coaxially arranged with cavity main body;It further includes air inlet and air outlet, air inlet is circularly opened in the sidewall top of the cavity main body;Air outlet is opened in the top surface center of the cavity main body.The utility model determines suitable cavity wall surface material by optimizing cavity structure, reasonably selecting air inlet and air outlet position, solves the problem of wafer temperature uneven in prior art, and realizes wafer automatic taking through intelligent automatic wafer transfer assembly structure under the form of not changing cavity structure, improves the quality and efficiency of semiconductor wafer manufacturing.

Description

Technical Field

[0001] This utility model belongs to the field of semiconductor manufacturing technology, specifically, it relates to an integrated device for uniform control and automated transfer of wafer temperature during hot plate evacuation. Background Technology

[0002] In semiconductor wafer manufacturing, hot plate evacuation is a crucial auxiliary step in key processes such as photolithography and thin film deposition. Its core objective is to ensure the uniformity of photoresist curing and thin film growth by precisely controlling the wafer temperature. However, existing cavity structures used for hot plate evacuation have the following drawbacks:

[0003] Unreasonable airflow distribution: The improper design of the air inlet and outlet positions of traditional cavities leads to turbulence or dead zones in the airflow within the cavity, resulting in uneven heat exchange on the wafer surface, causing large local temperature deviations, which in turn leads to quality problems such as wafer warping and abnormal electrical performance; seriously affecting the electrical performance and yield of the wafer, and failing to meet the needs of high-precision semiconductor manufacturing.

[0004] Poor temperature control stability: The cavity wall material is mostly made of stainless steel or titanium alloy. The former has a low thermal conductivity, making it difficult to achieve rapid heat transfer, while the latter is expensive and not conducive to large-scale application.

[0005] Low level of automation: wafer handling relies heavily on manual or semi-automated equipment, resulting in low operational efficiency. A single handling process takes more than 30 seconds and is prone to human error, leading to wafer contamination or damage.

[0006] Therefore, designing a cavity structure that can achieve uniform temperature control of wafers, is simple in structure, low in cost, and highly automated has become a technical problem to be solved in this field. Utility Model Content

[0007] The purpose of this invention is to provide an integrated device for uniform control and automated transfer of wafer temperature during hot plate evacuation. Compared with the prior art, this invention solves the problem of uneven wafer temperature in the prior art by optimizing the cavity structure, rationally selecting the positions of the air inlet and outlet, and determining the appropriate cavity wall material. Furthermore, it achieves automated wafer handling through an intelligent automated structure without changing the shape of the cavity structure, thereby improving the quality and efficiency of semiconductor wafer manufacturing.

[0008] To solve the above problems, the technical solution adopted by this utility model is as follows: It includes a heat cover assembly, which comprises a heat cover upper plate, a heat cover heating element, and a heat cover lower plate arranged sequentially from top to bottom. The heat cover assembly is slidably mounted on sliding components on both sides of the device. The upper heat cover lower plate, the annular sealing disc, and the lower heat plate form a disc-shaped cavity body with a planar top. The upper surface of the heat plate is perpendicular to the central axis of the cavity body, and the sealing disc is coaxially arranged with the cavity body. It also includes an air inlet and an air outlet. The air inlet is annularly located on the top of the side wall of the cavity body; the air outlet is located at the center of the top surface of the cavity body.

[0009] Furthermore, the wall of the cavity body is made of aluminum 6061 material.

[0010] Furthermore, the inner wall of the air inlet smoothly transitions with the inner wall of the cavity body.

[0011] Furthermore, the lower edge of the air inlet is 1 mm away from the top plane of the cavity body.

[0012] Furthermore, the inner wall of the air outlet is provided with a chamfered structure, and the chamfer angle is 45°.

[0013] Furthermore, it also includes an automated wafer transfer assembly, the automated wafer transfer assembly comprising:

[0014] The lifting and lowering sealing plate is driven by a cylinder to achieve lifting and lowering; the wafer carrier stage is set below the hot plate, and its edge is provided with an annular protrusion for radial positioning of the wafer. The annular protrusion is on the same horizontal plane as the upper surface of the hot plate, and the diameter of the wafer carrier stage is smaller than the diameter of the cavity body.

[0015] A liftable lifting pin assembly includes at least three lifting pins that are evenly distributed around the circumference of the wafer carrier stage and are lifted and lowered by a motor-driven lead screw to lift or lower the wafer; a cold plate is disposed on the outside of the cavity body and is moved along the central axis of the cavity body by a horizontal moving mechanism to support and transfer the wafer.

[0016] Furthermore, the horizontal moving mechanism includes a linear guide rail and a servo motor, with the servo motor electrically connected to an external power source.

[0017] Furthermore, the cold plate is provided with at least two receiving slots for accommodating lifting pins, and one of the receiving slots can accommodate at least two lifting pins.

[0018] Furthermore, the bottom of the wafer carrier stage is hollow and cooled by air passing through an air passage.

[0019] Furthermore, the outer wall of the cavity body is provided with at least three temperature sensor interfaces, which are evenly distributed along the circumference of the cavity body for connecting temperature sensors to monitor the temperature distribution inside the cavity.

[0020] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0021] 1. By optimizing the position of the air inlet and outlet, and the design of the disc-shaped cavity body, a stable and uniform airflow field can be formed during the hot plate extraction process, so as to achieve uniform heat exchange on the wafer surface, effectively maintain the uniform temperature of the wafer, significantly improve the temperature control accuracy in the semiconductor wafer manufacturing process, reduce wafer quality problems caused by uneven temperature, and improve the product yield.

[0022] 2. The cavity wall material is aluminum 6061, which fully combines the temperature conditions during the hot plate extraction process and the cavity usage requirements. While ensuring good thermal conductivity and mechanical strength, it also takes into account cost and processing difficulty, further improving the overall performance and market competitiveness of the invention.

[0023] 3. The cavity top adopts a planar top structure, which significantly reduces processing difficulty and cost while meeting the requirements for wafer temperature uniformity, improves production efficiency, and facilitates large-scale production applications. At the same time, it avoids the complex mesh plate design and calculations required for conical structures, simplifying the manufacturing process; and the use of aluminum 6061 material reduces material costs, resulting in a significant decrease in overall cost.

[0024] 4. Automated transfer; the component reduces the single wafer pick-and-place time to less than 10 seconds, greatly improving efficiency and avoiding the risk of contamination caused by manual operation;

[0025] In summary, this invention significantly improves wafer temperature uniformity during hot plate extraction by optimizing cavity structure, inlet / outlet design, material selection, and automated component integration. It also reduces costs and increases production efficiency, and can be widely applied in the manufacturing processes of 12-inch and smaller semiconductor wafers. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the cavity body structure of this utility model;

[0027] Figure 2 This is a schematic diagram showing the position and structure of the baked wafer and outer sealing disk in the assembly according to this utility model;

[0028] Figure 3 This is a schematic diagram of the structure of the outer sealing disc of this utility model, in which the position is lowered by a cylinder.

[0029] Figure 4This is a three-dimensional structural diagram of the present invention, which uses a motor to control the position of the lifting pin via a lead screw to lift the wafer.

[0030] Figure 5 This is a schematic diagram of the cross-sectional structure of the present invention, in which the lifting pin is raised by a motor through a lead screw to lift the wafer.

[0031] Figure 6 This is a three-dimensional structural diagram of the cold plate moving horizontally to the position between the hot plate and the wafer according to this utility model;

[0032] Figure 7 This is a schematic cross-sectional view of the cold plate moving horizontally to the position between the hot plate and the wafer according to this utility model.

[0033] Figure 8 This is a three-dimensional structural diagram of the lifting pin descending and the wafer being transferred onto the cold plate according to this utility model;

[0034] Figure 9 This is a cross-sectional view of the lifting pin descending and the wafer being transferred to the cold plate according to the present invention.

[0035] Figure 10 This is a schematic diagram of the structure for moving the cold plate to its original position and removing the wafer according to the present invention.

[0036] Figure 11 This is a schematic diagram of the structure of the robotic arm of this utility model for removing wafers;

[0037] Figure 12 This is a simulation diagram of the overall airflow heat dissipation within the cavity of this utility model;

[0038] Figure 13 This is a simulation diagram of the airflow heat dissipation cross section inside the cavity of this utility model;

[0039] In the diagram: 1. Upper heat cover plate; 2. Heating plate of the heat cover; 3. Lower heat cover plate; 4. Sealing plate; 5. Hot plate; 6. Main body of the cavity; 7. Air inlet; 8. Air outlet; 9. Cylinder; 10. Wafer support stage; 11. Annular protrusion; 12. Lifting pin; 13. Wafer; 14. Cold plate; 15. Linear guide rail; 16. Servo motor; 17. Receiving groove; 18. Air duct; 19. Heat cover air duct. Detailed Implementation

[0040] To more clearly illustrate the overall concept of this utility model, a detailed description will be provided below with reference to the accompanying drawings.

[0041] It should be noted that many specific details are set forth in the following description to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below. Furthermore, it should be understood that in the description of the present invention, terms such as "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0042] The present invention will be further described below with reference to specific embodiments.

[0043] This utility model provides an integrated device for uniform wafer temperature control and automated transfer during hot plate evacuation, such as... Figure 1 As shown, the device includes a heat cover assembly, which comprises a heat cover upper plate 1, a heat cover heating element 2, and a heat cover lower plate 3 arranged sequentially from top to bottom. The heat cover assembly is slidably mounted on sliding components on both sides of the device. The heat cover lower plate 3, the annular sealing disc 4, and the heat plate 5 form a disc-shaped cavity body 6, the top of which is a planar structure. The upper surface of the heat plate 5 is perpendicular to the central axis of the cavity body 6, and the sealing disc 4 is coaxially arranged with the cavity body 6. The device also includes an air inlet 7 and an air outlet 8. The air inlet 7 is annularly located on the top of the side wall of the cavity body 6, and the air outlet 8 is located at the center of the top surface of the cavity body 6.

[0044] Preferably, the wall of the cavity body 6 is made of aluminum 6061 material; the inner wall of the air inlet 7 smoothly transitions with the inner wall of the cavity body 6; the vertical distance between the lower edge of the air inlet 7 and the top plane of the cavity body 6 is 1mm; the inner wall of the air outlet 8 is provided with a chamfer structure, and the chamfer angle is 45°.

[0045] In the actual manufacturing of this cavity environment, high-precision machining equipment was first selected. Following the dimensional requirements of 330mm diameter and 30mm height, suitable machining processes were used to process the aluminum 6061 material into a disc-shaped cavity body 6. The top of the disc-shaped cavity body 6 is a planar structure. During the machining of the top plane, the flatness was strictly controlled to ensure a smooth and even surface, guaranteeing uniform airflow distribution. From the perspective of heat exchange and airflow distribution, the conical structure in the design of the cavity top shape can guide airflow to more evenly cover the surface of wafer 13. During the extraction process of the hot plate 5, it allows the airflow to fully contact all parts of wafer 13, contributing to more uniform heat exchange. Theoretically, it is superior to the planar structure in maintaining the uniform temperature of wafer 13. However, the conical structure faces many challenges in actual machining. Its complex curved shape requires special machining equipment and complex machining processes, which not only significantly increases machining costs but also significantly prolongs the machining cycle and reduces production efficiency. Furthermore, if a conical structure is adopted, a perforated plate is required to further optimize airflow distribution. Precisely calculating the position and size of the perforations involves complex fluid dynamics calculations and extensive experimental verification, which undoubtedly increases the difficulty and cost of design and manufacturing. Considering factors such as processing difficulty, cost, production efficiency, and the complexity of supporting components, a flat surface was ultimately chosen for the top shape of the cavity. By rationally designing the positions of the air inlet 7 and outlet 8, as well as the airflow parameters, the planar cavity structure can achieve uniform temperature on wafer 13 even when the hot plate 5 is evacuating, meeting production requirements. Therefore, compared to a conical structure, the planar structure reduces processing difficulty (eliminating the need for complex curved surface processing equipment), lowers processing costs, shortens the processing cycle by more than 40%, and avoids the need for the perforated plate design required for a conical structure, thus simplifying the manufacturing process.

[0046] The air inlet 7 is a ring-shaped opening located on the top of the side wall of the cavity body 6, with its lower edge 1mm from the top plane. During the fabrication of the air inlet 7, a ring-shaped opening is precisely machined 1mm from the top of the side wall. Strict control is maintained over the dimensional accuracy and ring uniformity of the air inlet 7 during the fabrication process to ensure uniform gas entry into the cavity. When the air inlet 7 is positioned low on the side wall, during the extraction process of the hot plate 5, the airflow tends to accumulate at the bottom of the cavity, making it difficult to rise quickly and diffuse evenly to the surface of the wafer 13. This results in a difference in heat exchange between the bottom and top of the wafer 13, causing uneven temperature distribution. If the air inlet 7 is positioned in the middle of the side wall, the airflow will be obstructed by the cavity wall during its ascent, generating turbulence and eddies, leading to disordered airflow distribution and hindering stable and uniform heat exchange with the wafer 13, which is also detrimental to maintaining uniform temperature of the wafer 13. Positioning the air inlet 7 as a ring at the top 1mm of the side wall, as... Figure 12 and Figure 13As shown, the airflow can enter the cavity body 6 in a relatively gentle manner, and with its own inertia and gravity, it can quickly and evenly diffuse to the surface of the wafer 13. Under the negative pressure of the hot plate 5, the airflow can stably sweep across the surface of the wafer 13, carrying away the heat from the surface of the wafer 13, achieving uniform heat exchange, and effectively maintaining the uniform temperature of the wafer 13;

[0047] The air outlet 8 is located at the center of the top surface, with a diameter of 1 / 10 of the diameter of the main body 6 of the cavity. The inner wall is chamfered at 45°. This design can reduce the airflow outlet resistance, increase the air extraction rate, and avoid temperature fluctuations caused by the formation of local negative pressure at the outlet.

[0048] The walls of the cavity body 6 are made of aluminum 6061, which has a much higher thermal conductivity than stainless steel, enabling rapid heat transfer within the cavity. Furthermore, its cost is significantly lower than that of titanium alloys, making it suitable for mass production. In practical applications, the maximum temperature of this cavity environment is only 200°C. While stainless steel possesses good strength and corrosion resistance, its relatively poor thermal conductivity hinders the rapid and uniform heat transfer and distribution within the cavity body 6 during the evacuation process of the hot plate 5, potentially leading to excessively high or low temperatures in certain areas of the wafer 13. Titanium alloys offer high strength, low density, and good corrosion resistance, but their high price significantly increases manufacturing costs, making them unsuitable for large-scale production. Aluminum 6061, on the other hand, is an aluminum alloy that maintains good physical properties and mechanical strength even at 200°C. It has a high thermal conductivity, which can effectively promote the rapid transfer and uniform distribution of heat in the cavity body 6. During the evacuation process of the hot plate 5, it helps to balance the surface temperature of the wafer 13. At the same time, aluminum 6061 has good processing performance and is easy to perform various forming and processing operations, which can meet the processing requirements of the complex cavity structure of this utility model. Moreover, the cost is relatively low and it is suitable for large-scale production.

[0049] Preferably, it also includes an automated wafer transfer assembly, the automated wafer transfer assembly comprising:

[0050] The liftable sealing disc 4 is driven by a cylinder 9 to lift and lower, opening the cavity for easy loading and unloading of the wafer 13. The wafer carrier stage 10 is located below the hot plate 5, with an annular protrusion 11 on its edge for radial positioning of the wafer 13. The annular protrusion 11 is on the same horizontal plane as the upper surface of the hot plate 5, and the diameter of the wafer carrier stage 10 is smaller than the diameter of the cavity body 6. The liftable lifting pin assembly includes at least three lifting pins 12, which are evenly distributed around the circumference of the wafer carrier stage 10 and are lifted and lowered by a motor-driven lead screw for lifting or lowering the wafer 13. This structure is designed to lift the wafer 13 to a certain height away from the wafer carrier stage 10, avoiding scratches caused by direct contact.

[0051] A cold plate 14 is disposed on the outside of the cavity body 6 and moves along the central axis of the cavity body 6 via a horizontal moving mechanism to carry and transfer the wafer 13. The cold plate 14 is also provided with an annular cold water channel, which is connected to an external chiller to achieve uniform cooling of the wafer 13. The horizontal moving mechanism includes a linear guide rail 15 and a servo motor 16, which is electrically connected to an external power source.

[0052] Preferably, the cold plate 14 is provided with at least two receiving grooves 17 for accommodating the lifting pins 12, and one of the receiving grooves 17 can accommodate at least two lifting pins 12. This design facilitates the insertion of the cold plate 14.

[0053] Preferably, the bottom of the wafer carrier stage 10 is hollow and is cooled by air introduced through the air passage 18.

[0054] Preferably, the outer wall of the cavity body 6 is provided with at least three temperature sensor interfaces, which are evenly distributed along the circumference of the cavity body 6, for connecting temperature sensors to monitor the temperature distribution inside the cavity.

[0055] The working principle of this utility model is as follows:

[0056] When using this cavity environment in conjunction with the hot plate 5 for evacuation, the wafer 13 is stably placed in a suitable position inside the cavity, ensuring that the surface of the wafer 13 is parallel to the top of the cavity. The evacuation equipment is turned on, creating a negative pressure environment inside the cavity. Simultaneously, external gas enters the cavity body 6 through the annular air inlet 7 located 1mm from the top of the side wall. The gas flow rate and velocity at the air inlet 7 are controlled. A target flow rate is preset according to process requirements. The flow meter monitors the actual flow rate in real time and feeds it back to the control system. The flow control valve dynamically adjusts the valve opening using a PID algorithm to stabilize the actual flow rate within the target value. The flow velocity is indirectly controlled through the conversion relationship between flow rate and the area of ​​the air inlet 7. This invention primarily utilizes the special position and shape design of the air inlet 7 to allow gas to diffuse evenly into the cavity, and under the negative pressure generated by evacuation, ensures a stable and uniform airflow over the surface of the wafer 13. During this process, the gas exchanges heat thoroughly with the wafer 13, carrying away heat from its surface. The heat-carrying gas then converges at the air outlet 8 at the center of the top surface and exits the main body 6 of the cavity. The heat-carrying gas flows out through the hot-cover air duct 19 at the air outlet 8. Through continuous airflow circulation, uniform heat transfer and dissipation from the wafer 13 surface are achieved, thus maintaining a uniform internal temperature of the wafer 13 during the extraction process of the hot plate 5. By monitoring the temperature changes at different locations on the wafer 13 in real time, the extraction rate and gas parameters at the air inlet 7 can be flexibly adjusted according to actual conditions to achieve optimal temperature uniformity of the wafer 13.

[0057] After the evacuation operation is completed, the wafer 13 transfer steps are as follows: Figures 2-11 As shown (the hot cover assembly has been hidden in all non-sectional views for clarity of action), the hot cover assembly located on the upper side of the outer sealing plate 4 is first opened. Then, the outer sealing plate 4 is driven down by the cylinder 9 to open the cavity. The baked wafer 13 is lifted to a certain height by the lifting pin assembly driven by the servo motor 16 through the lead screw. The side cold plate 14 is moved horizontally between the wafer 13 and the hot plate 5 through the linear guide rail 15 and the servo motor 16. Then, the lifting pin assembly descends, causing the wafer 13 to fall onto the cold plate 14 for cooling. Finally, the cold plate 14 is reset and transferred to the next process along with the cooled wafer 13.

[0058] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention.

Claims

1. An integrated device for uniform temperature control and automated transfer of wafers during hot plate evacuation, comprising a hot cover assembly, wherein the hot cover assembly comprises a hot cover upper plate (1), a hot cover heating element (2), and a hot cover lower plate (3) arranged sequentially from top to bottom, the hot cover assembly being slidably mounted on sliding components on both sides of the device, characterized in that, The upper heat cover plate (3), the ring-shaped sealing disc (4), and the lower heat plate (5) form a disc-shaped cavity body (6), the top of which is a planar structure. The upper surface of the heat plate (5) is perpendicular to the central axis of the cavity body (6), and the sealing disc (4) is coaxially arranged with the cavity body (6). It also includes an air inlet (7) and an air outlet (8). The air inlet (7) is ring-shaped and opened on the top of the side wall of the cavity body (6). The air outlet (8) is opened at the center of the top surface of the cavity body (6).

2. The integrated device for uniform wafer temperature control and automated transfer during hot plate evacuation as described in claim 1, characterized in that, The wall of the cavity body (6) is made of aluminum 6061 material.

3. The integrated device for uniform wafer temperature control and automated transfer during hot plate evacuation as described in claim 1, characterized in that, The inner wall of the air inlet (7) smoothly transitions with the inner wall of the cavity body (6).

4. The integrated device for uniform wafer temperature control and automated transfer during hot plate evacuation as described in claim 3, characterized in that, The lower edge of the air inlet (7) is 1 mm away from the top plane of the cavity body (6).

5. The integrated device for uniform wafer temperature control and automated transfer during hot plate evacuation as described in claim 1, characterized in that, The inner wall of the air outlet (8) is provided with a chamfered structure, and the chamfer angle is 45°.

6. The integrated device for uniform wafer temperature control and automated transfer during hot plate evacuation as described in claim 1, characterized in that, It also includes an automated wafer transfer assembly, which comprises: The lifting and lowering sealing disc (4) is driven by a cylinder (9) to achieve lifting and lowering; A wafer carrier stage (10) is located below the hot plate (5), and its edge is provided with an annular protrusion (11) for radially limiting the wafer (13). The annular protrusion (11) is on the same horizontal plane as the upper surface of the hot plate (5), and the diameter of the wafer carrier stage (10) is smaller than the diameter of the cavity body (6). The lifting pin assembly includes at least three lifting pins (12), which are evenly distributed around the circumference of the wafer carrier stage (10) and are lifted by a motor-driven lead screw to lift or lower the wafer (13). A cold plate (14) is disposed on the outside of the cavity body (6) and moves along the central axis of the cavity body (6) through a horizontal moving mechanism to carry and transfer the wafer (13).

7. The integrated device for uniform wafer temperature control and automated transfer during hot plate evacuation according to claim 6, characterized in that, The horizontal moving mechanism includes a linear guide rail (15) and a servo motor (16), which is electrically connected to an external power source.

8. The integrated device for uniform wafer temperature control and automated transfer during hot plate evacuation as described in claim 7, characterized in that, The cold plate (14) is provided with at least two receiving grooves (17) for accommodating the lifting needles (12), and one of the receiving grooves (17) can accommodate at least two lifting needles (12).

9. The integrated device for uniform wafer temperature control and automated transfer during hot plate evacuation according to claim 6, characterized in that, The bottom of the wafer carrier stage (10) is hollow and is cooled by air through the air passage (18).

10. The integrated device for uniform wafer temperature control and automated transfer during hot plate evacuation according to any one of claims 1-9, characterized in that, The outer wall of the cavity body (6) is provided with at least 3 temperature sensor interfaces, which are evenly distributed along the circumference of the cavity body (6) for connecting temperature sensors to monitor the temperature distribution inside the cavity.

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