Wafer transfer apparatus for semiconductor vacuum processing

Abstract

The application discloses a wafer conveying device for semiconductor vacuum processing, which is used for conveying wafers between different processing chambers. A valve plate with temperature adjusting function is arranged in the vacuum conveying valve, and a temperature control system is used to monitor and adjust the temperature of the valve plate in real time, so that the temperature of the valve plate is kept stable during the opening process of the vacuum conveying valve. Meanwhile, the temperature control system introduces a feedforward compensation prediction model based on the motion state of the valve plate, which can intervene in heating in advance at the moment when the valve plate is opened and the heat radiation is reduced, effectively offsetting the interference of external environmental changes on the temperature of the valve plate, so that the surface temperature of the valve plate is kept highly stable during the whole stroke movement of the valve, the film stress caused by repeated thermal expansion and cold contraction of the valve plate is directly eliminated, the adhesion of the deposited film on the surface of the valve plate is significantly enhanced, the film peeling and particle generation are inhibited from the root, and the cleanliness of the wafer processing chamber is greatly improved, and the yield and equipment reliability of the wafer processing are improved.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor vacuum process technology and relates to the transfer of wafers between processing chambers of multiple different processes, specifically a wafer transfer device for semiconductor vacuum processes. Background Technology

[0002] In wafer transfer equipment for semiconductor vacuum processes, vacuum transfer valves control the entry and exit of wafers from wafer processing chambers. When the vacuum transfer valve is open, a robotic arm installed within the wafer transfer chamber transfers the wafer between different wafer processing chambers. During wafer processing, a thin film composed of reactive materials is deposited on the inner wall of the wafer processing chamber and the surface of the valve plate of the vacuum transfer valve. During wafer transfer, when the vacuum transfer valve is open, the valve plate rises, significantly reducing the heat radiation it receives from the wafer processing chamber. Due to the small heat capacity and long heat conduction path of the valve plate, this leads to a drop in valve plate temperature, with temperature fluctuations reaching 5-70 degrees Celsius. This temperature fluctuation causes changes in thermal stress in the deposited film on the valve plate surface. Repeated expansion and contraction weaken the film's adhesion, causing the film on the valve plate surface to peel off and form microparticles within the wafer processing chamber, severely impacting wafer yield and equipment maintenance cycles. Summary of the Invention

[0003] To address the technical problems existing in the background art, this invention proposes a wafer transfer device for semiconductor vacuum processes. It utilizes a temperature control system to monitor and adjust the temperature of the valve plate in real time, ensuring that the valve plate temperature remains stable during the opening of the vacuum transfer valve. This avoids the problem of the valve plate surface film peeling off due to large temperature fluctuations, thereby improving the wafer yield.

[0004] The objective of this invention can be achieved through the following technical solutions: A wafer transfer device for semiconductor vacuum processes includes: a wafer transfer chamber and multiple wafer processing chambers connected to the wafer transfer chamber. Vacuum transfer valves are installed between the wafer transfer chamber and the multiple wafer processing chambers. Each vacuum transfer valve has a valve plate, which is raised or lowered to open or close the vacuum transfer valve. The valve plate has a temperature regulation function, forming a temperature control surface at the end of the valve plate facing the wafer processing chamber. The surface temperature of the temperature control surface is monitored and adjusted in real time by a temperature control system to keep the surface temperature of the temperature control surface of the valve plate stable during the opening or closing of the vacuum transfer valve.

[0005] Furthermore, the valve plate includes: a plate body, a heating element, and a wire. The temperature control surface is located at one end of the plate body. A hollow cavity is provided inside the plate body. The heating element is embedded in the hollow cavity of the plate body. One end of the wire is electrically connected to the heating element, and the other end extends out of the plate body to connect to the temperature control system, so as to drive the heating element to heat the plate body through the temperature control system and adjust the surface temperature of the temperature control surface.

[0006] Furthermore, the temperature control system includes: a first temperature sensor, a second temperature sensor, a controller, and a power regulator. The first temperature sensor is installed on the temperature control surface of the valve plate to detect the surface temperature of the valve plate temperature control surface in real time. The second temperature sensor is installed on the inner wall of the wafer processing chamber to detect the surface temperature of the inner wall of the wafer processing chamber in real time. The input terminal of the controller is communicatively connected to the first temperature sensor and the second temperature sensor respectively. The output terminal of the controller is connected to the power regulator. The power regulator is electrically connected to the heating element to output a control signal to the power regulator based on the temperature difference detected by the first temperature sensor and the second temperature sensor, thereby adjusting the heating power of the heating element so that the surface temperature of the valve plate temperature control surface is consistent with the surface temperature of the inner wall of the wafer processing chamber.

[0007] Furthermore, the vacuum transmission valve also includes a valve body and a drive mechanism. The valve plate is slidably connected to the valve body, and the drive mechanism drives the valve plate to move vertically up and down within the valve body to open or close the valve body opening.

[0008] Furthermore, the controller is electrically connected to the drive mechanism and receives action signals from the drive mechanism. When the valve plate rises to open the valve body opening, the controller performs feedforward compensation according to the preset prediction model, and increases the heating power of the heating element in advance so that the temperature remains stable after the valve plate rises.

[0009] Furthermore, the preset prediction model is as follows: based on the temperature inside the wafer transfer chamber and the temperature inside the wafer processing chamber, the compensation power required at any moment after the valve plate begins to rise is calculated in real time, and then superimposed on the output of the controller to determine the final heating power of the heating element.

[0010] Furthermore, the outline of the hollow cavity matches the temperature control surface, and multiple heating elements are arranged in an array within the hollow cavity to uniformly heat the temperature control surface of the valve plate, thereby synchronously raising the surface temperature of the entire temperature control surface.

[0011] Furthermore, the hollow cavity is filled with a heat-conducting medium layer, which wraps around the heating element. The heat-conducting medium layer is attached to the inner wall of the hollow cavity on the side opposite to the temperature control surface to improve the heat transfer efficiency between the heating element and the temperature control surface.

[0012] Furthermore, the other end of the board opposite the temperature control surface is set as an insulation surface, so that the insulation surface faces the wafer transfer chamber. The surface of the insulation surface is provided with a heat insulation layer to reduce the heat loss of the board.

[0013] Furthermore, the hollow cavity is designed as a closed structure, and the wires are led out of the plate through a sealed lead hole opened on one side of the plate.

[0014] The beneficial effects of this invention are as follows: The wafer transfer device provided by this invention is applied to the transfer of wafers between different processing chambers in semiconductor vacuum processes. By setting a valve plate with temperature regulation function inside the vacuum transfer valve, and using a temperature control system to monitor and adjust the temperature of the valve plate in real time, the temperature of the valve plate remains stable during the opening of the vacuum transfer valve. Simultaneously, the temperature control system introduces a feedforward compensation prediction model based on the valve plate's motion state, which can intervene in heating in advance at the moment the valve plate opens and heat radiation decreases, effectively offsetting the interference of external environmental changes on the valve plate temperature. This ensures that the surface temperature of the valve plate remains highly stable throughout the entire valve stroke, directly eliminating the film stress caused by repeated thermal expansion and contraction of the valve plate, significantly enhancing the adhesion of the deposited thin film on the valve plate surface, fundamentally inhibiting film peeling and particle generation, greatly improving the cleanliness of the wafer processing chamber, and increasing the yield and equipment reliability of the wafer process. In summary, this invention not only significantly extends the equipment maintenance cycle and reduces operation and maintenance costs, but also effectively improves the yield and consistency of the wafer process by stabilizing the process environment, providing a highly reliable solution for semiconductor vacuum processes. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the present invention.

[0016] Figure 2 This is a schematic diagram of the vacuum transmission valve of the present invention.

[0017] Figure 3 This is a three-dimensional schematic diagram of the valve plate of the present invention.

[0018] Figure 4 This is a cross-sectional view of the valve plate of the present invention.

[0019] Figure 5 for Figure 4 Enlarged diagram of point A in the middle.

[0020] Figure 6 This is a three-dimensional schematic diagram of the lower plate of the valve plate of the present invention.

[0021] Figure 7 This is a schematic diagram of the temperature control system of the present invention. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] like Figure 1As shown, the present invention provides a wafer transfer device for semiconductor vacuum processes, including: a wafer transfer chamber 10 and a plurality of wafer processing chambers 20 connected to the wafer transfer chamber 10. Vacuum transfer valves 30 are installed between the wafer transfer chamber 10 and the plurality of wafer processing chambers 20. When the vacuum transfer valves 30 are opened, the wafer is transferred between different wafer processing chambers 20 by a robot arm installed in the wafer transfer chamber 10.

[0024] like Figure 2 As shown, the vacuum transfer valve includes: a valve body 1, a valve plate 2, and a drive mechanism 3. A groove is provided on the side wall surrounding the opening of the valve body 1. The valve plate 2 is slidably connected within the groove, allowing it to move vertically up and down within the opening of the valve body 1. When the valve plate 2 rises, the opening of the valve body 1 opens; when the valve plate 2 falls, the opening of the valve body 1 closes. The drive mechanism 3 is mounted on one side of the valve body 1 and can be a cylinder, motor, or bellows assembly. The drive mechanism 3 is connected to the valve plate 2 via a valve stem 4, driving the valve plate 2 to rise and fall within the valve body 1, thus opening or closing the opening of the valve body 1.

[0025] The valve plate 2 has a temperature regulation function, forming a temperature control surface at the end of the valve plate 2 facing the wafer processing chamber 20. Since a thin film composed of wafer material is deposited on both the inner wall of the wafer processing chamber 20 and the temperature control surface of the valve plate 2 during semiconductor CVD processes, a temperature control system is also provided in the wafer transfer equipment. This system monitors and adjusts the surface temperature of the temperature control surface of the valve plate 2 in real time, ensuring that the surface temperature remains stable during the opening and closing of the vacuum transfer valve. This prevents repeated expansion and contraction caused by temperature changes, which could lead to a decrease in film adhesion, effectively suppressing film peeling and particle generation, and significantly improving wafer process yield and equipment reliability.

[0026] like Figures 3-6 As shown, the valve plate 2 includes: a plate body 21, a heating element 22, and a wire 23. The plate body 21 is assembled from an upper plate 211 and a lower plate 212. The lower plate 212 has a mounting groove 213, and the upper plate 211 is fitted into the mounting groove 213 and fixed by bolts 214. The upper plate 211 and the lower plate 212 are sealed together, forming a closed hollow cavity 24 between them. The heating element 22 is embedded in the hollow cavity 24. The heating element 22 uses heating plates or heating wires to actively heat the plate body 21, thereby realizing the temperature regulation function of the valve plate 2. Specifically, the temperature control surface is located on the outer end face of the upper plate 211, and the contour of the hollow cavity 24 matches the temperature control surface. Multiple heating elements 22 are arranged in an array within the hollow cavity 24 to uniformly heat the temperature control surface of the valve plate 2, so that the surface temperature of the entire temperature control surface rises synchronously.

[0027] The plate 21 is made of stainless steel, with the temperature control surface being a metal surface. A sealing rubber ring 25 is provided around the periphery of the plate 21. The valve plate 2 is sealed to the valve body 1 opening through the sealing rubber ring 25, achieving a vacuum seal. The hollow cavity 24 of the plate 21 is filled with thermally conductive silicone grease as a thermally conductive medium layer 26. The heating element or heating wire is embedded in the thermally conductive silicone grease, so that the thermally conductive medium layer 26 encapsulates the heating element 22. The thermally conductive medium layer 26 is attached to the inner end face of the upper plate 211 to improve the heat transfer efficiency between the heating element 22 and the temperature control surface. A layer of thermal insulation coating is sprayed onto the outer end face of the lower plate 212 to form a thermal insulation layer 27, so that the outer end face of the lower plate 212 serves as the insulation surface, and the insulation surface faces the wafer transfer chamber 10 to reduce heat loss from the plate 21.

[0028] One end of the wire 23 is electrically connected to the heating element 22, and the other end extends out of the plate 21 and connects to the temperature control system. The temperature control system drives the heating element 22 to heat the plate 21, adjusting the surface temperature of the temperature-controlled surface to maintain a stable surface temperature. Specifically, a slot 28 is provided on one side of the lower plate 212 of the plate 21. The valve stem 4 is inserted into the slot 28 and fixedly connected to the valve plate 2. The wire 23 is led out of the plate 21 from one side of the lower plate 212 through a sealed lead hole 29 on the periphery of the slot 28, and runs along the outer side of the valve stem 4 to connect to the temperature control system. Specifically, the wire 23 running along the outer side of the valve stem 4 is a spiral flexible wire surrounding the valve stem 4 to absorb the movement of the valve plate 2 and prevent the wire 23 from breaking due to repeated bending.

[0029] like Figure 7 As shown, the temperature control system includes: a controller, a first temperature sensor, a second temperature sensor, a third temperature sensor, and a power regulator. The first temperature sensor is embedded inside or on the surface of the temperature control surface of the valve plate 2 to detect the surface temperature of the temperature control surface of the valve plate 2 in real time. The second temperature sensor is installed on the inner wall of the wafer processing chamber 20 to detect the surface temperature of the inner wall of the wafer processing chamber 20 in real time. The controller uses an industrial-grade PID controller, whose input terminals are communicatively connected to the first temperature sensor and the second temperature sensor, respectively, to receive... and The signal output is connected to a power regulator, which is electrically connected to the heating element 22 to control the heating power of the heating element 22. The controller has pre-set control logic: when... and When the temperature difference exceeds a preset threshold (e.g., ±2℃), the controller calculates the PID output based on the temperature difference and adjusts the heating power of the heating element 22 to make... Approaching This ensures that the surface temperature of the temperature control surface of valve plate 2 remains stable.

[0030] Specifically, since the main temperature changes of valve plate 2 occur during its lifting and lowering process, when valve plate 2 rises, the heat radiation received from the wafer processing chamber 20 is significantly reduced, causing the temperature of valve plate 2 to begin to drop. Therefore, a predictive model for the temperature change of valve plate 2 is preset in the controller, and the controller is electrically connected to the drive mechanism 3. The controller receives the action signal from the drive mechanism 3. When it detects that valve plate 2 has risen and opened the valve body 1, the controller performs feedforward compensation according to the preset predictive model, increasing the heating power of the heating element 22 in advance so that the temperature of valve plate 2 does not drop rapidly after it rises, further ensuring that the surface temperature of the temperature-controlled surface of valve plate 2 remains stable.

[0031] Specifically, in this invention, the heat exchange of the valve plate 2 in the vacuum environment mainly includes: radiative heat exchange with the wafer processing chamber 20 when the valve is closed; radiative heat exchange with the wafer transfer chamber 10 when the valve is open; and heating provided by the heating element 22. Therefore, a third temperature sensor is installed on the inner wall of the wafer transfer chamber 10 to detect the temperature inside the wafer transfer chamber 10 in real time. Furthermore, the third temperature sensor is connected in communication with the controller. Therefore, the thermal dynamics of valve plate 2 can be approximated as a first-order inertial system: ; in, For the heat capacity of valve plate 2, The equivalent thermal resistance between valve plate 2 and the environment; The heating power of heating element 22; Assuming an ambient equivalent temperature, when valve plate 2 is raised, When valve plate 2 descends, ; This refers to the time it takes for valve plate 2 to rise.

[0032] Define thermal time constant ,in, and All values ​​are fixed and can be obtained through experimental measurement or theoretical calculation. Rearranging the above formula, we get: ; When the drive mechanism 3 drives the valve plate 2 to rise, the ambient temperature... Depend on Become Without heating provided by heating element 22, the temperature of valve plate 2 will decrease exponentially: ; The rate at which the temperature of valve plate 2 decreases is: ; To maintain and The heating element 22 is required to provide the necessary heat. According to the thermal dynamics equation, the compensation power required by the heating element 22 should be: ; However, the actual heating power of the heating element 22 cannot reach any value instantaneously, and the heating response delay must be considered. Therefore, the feedforward compensation power of the prediction model used in this invention is: ; in, For adjustable feedforward gain, it is usually set to... The nearest value can be continuously trained and optimized based on historical data. This prediction model... The compensation amount is 0 when the valve plate 2 is first raised, and then gradually increases, which avoids power surges and provides sufficient heat when the temperature of the valve plate 2 begins to drop.

[0033] When valve plate 2 rises, the controller receives the action signal from drive mechanism 3 and immediately activates feedforward compensation according to the preset parameters. and Calculate the compensation power required at the current moment in real time. The power is then superimposed on the controller output to determine the final heating power of the heating element 22. When the valve plate 2 descends and closes again, the controller receives the action signal of the drive mechanism 3, automatically cancels the feedforward compensation, and the temperature control system reverts to pure PID control. Through the above predictive model and feedforward control strategy, this invention achieves precise dynamic tracking of the valve plate 2 temperature, and even under frequent valve opening and closing, temperature fluctuations can be controlled within ±1℃, greatly reducing the risk of film layer detachment on the valve plate 2.

[0034] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A wafer transfer device for semiconductor vacuum processes, characterized in that, include: A wafer transfer chamber (10) and multiple wafer processing chambers (20) connected to the wafer transfer chamber (10) are provided. Vacuum transfer valves (30) are installed between the wafer transfer chamber (10) and the multiple wafer processing chambers (20). Each vacuum transfer valve (30) has a valve plate (2) inside, which is used to open or close the vacuum transfer valve (30) by raising or lowering the valve plate (2). The valve plate (2) has a temperature regulation function, which forms a temperature control surface at the end of the valve plate (2) facing the wafer processing chamber (20), and monitors and adjusts the surface temperature of the temperature control surface in real time through a temperature control system. The temperature control system includes: a first temperature sensor, a second temperature sensor, and a controller. The first temperature sensor is installed on the temperature control surface of the valve plate (2) to detect the surface temperature of the temperature control surface of the valve plate (2) in real time. The second temperature sensor is installed on the inner wall of the wafer processing chamber (20) to detect the surface temperature of the wafer processing chamber (20) in real time. 20) The surface temperature of the inner wall. The input terminal of the controller is connected to the first temperature sensor and the second temperature sensor respectively. According to the temperature difference detected by the first temperature sensor and the second temperature sensor, the heating power of the valve plate (2) is adjusted so that the surface temperature of the temperature control surface of the valve plate (2) is consistent with the surface temperature of the inner wall of the wafer processing chamber (20). When the valve plate (2) is raised to open the opening of the valve body (1), the controller performs feedforward compensation according to the preset prediction model and increases the heating power of the valve plate (2) in advance so that the temperature of the valve plate (2) remains stable after it is raised. The preset prediction model is as follows: according to the temperature in the wafer transfer chamber (10) and the temperature in the wafer processing chamber (20), the compensation power required at any time after the valve plate (2) starts to rise is calculated in real time and superimposed on the output of the controller to determine the final heating power of the valve plate (2).

2. The wafer transfer device according to claim 1, characterized in that, The valve plate (2) includes: a plate body (21), a heating element (22), and a wire (23). The temperature control surface is located at one end of the plate body (21). A hollow cavity (24) is provided inside the plate body (21). The heating element (22) is embedded in the hollow cavity (24) of the plate body (21). One end of the wire (23) is electrically connected to the heating element (22), and the other end extends out of the plate body (21) to connect to the temperature control system, so as to drive the heating element (22) to heat the plate body (21) through the temperature control system and adjust the surface temperature of the temperature control surface.

3. The wafer transfer device according to claim 2, characterized in that, The temperature control system also includes a power regulator, which is electrically connected to the heating element (22). The output of the controller is connected to the power regulator so as to output a control signal to the power regulator based on the temperature difference detected by the first temperature sensor and the second temperature sensor, thereby adjusting the heating power of the heating element (22).

4. The wafer transfer device according to claim 1, characterized in that, The vacuum transmission valve (30) also includes a valve body (1) and a drive mechanism (3). The valve plate (2) is slidably connected inside the valve body (1). The drive mechanism (3) drives the valve plate (2) to move vertically up and down inside the valve body (1) to open or close the opening of the valve body (1).

5. The wafer transfer device according to claim 4, characterized in that, The controller is electrically connected to the drive mechanism (3) and receives action signals from the drive mechanism (3).

6. The wafer transfer device according to claim 2, characterized in that, The outline of the hollow cavity (24) matches the temperature control surface. Multiple heating elements (22) are arranged in an array inside the hollow cavity (24) to uniformly heat the temperature control surface of the valve plate (2) so that the surface temperature of the entire temperature control surface is raised synchronously.

7. The wafer transfer device according to claim 6, characterized in that, The hollow cavity (24) is filled with a thermally conductive medium layer (26), which wraps around the heating element (22). The thermally conductive medium layer (26) is attached to the inner wall of the hollow cavity (24) on the side opposite to the temperature control surface to improve the heat transfer efficiency between the heating element (22) and the temperature control surface.

8. The wafer transfer device according to claim 7, characterized in that, The other end of the plate (21) opposite the temperature control surface is set as the insulation surface, so that the insulation surface faces the wafer transfer chamber (10). The surface of the insulation surface is provided with a heat insulation layer (27) to reduce the heat loss of the plate (21).

9. The wafer transfer device according to claim 8, characterized in that, The hollow cavity (24) is set as a closed structure, and the wire (23) is led out of the plate (21) through the sealed lead hole (29) opened on one side of the plate (21).

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