Wafer palladium plating device

Abstract

The utility model provides a wafer palladium plating device. The wafer palladium plating device comprises a first tank body, a second tank body, a circulating pipeline and a gas-liquid mixing device, wherein the first tank body is used for accommodating a palladium solution so as to carry out palladium plating on a wafer; the second tank body is used for receiving the palladium solution overflowing from the first tank body; the circulating pipeline comprises a liquid inlet end and a liquid outlet end, the liquid inlet end is communicated with the second tank body, the liquid outlet end is communicated with the first tank body, and the circulating pipeline is used for enabling the palladium solution in the second tank body to flow back to the first tank body; and the gas-liquid mixing device is arranged on the circulating pipeline and is used for mixing the palladium solution from the second tank body with gas. According to the wafer palladium plating device, the uniformity of a flow field in the tank body can be improved, so that the palladium plating effect is improved, the precipitation of palladium in the tank body can be reduced, the service life of the device is prolonged, and the production cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductors, and in particular to a wafer palladium plating device. Background Art

[0002] In the semiconductor field, chemical palladium (Pd) plating process is widely used to protect the metal layer on semiconductor wafers. Especially when the electrode materials on semiconductor wafers are mostly aluminum alloys, palladium plating can effectively protect these difficult-to-plate substrates, extend the service life of the wafer, and improve product reliability and stability.

[0003] When depositing the palladium coating on wafers within the tank, the uneven flow field within the tank can lead to significant variations in the palladium coating thickness, resulting in poor quality. Palladium is extremely unstable in solution, and no element has yet been found to stabilize it. Furthermore, the solution within the tank undergoes an autocatalytic reaction, with the palladium element undergoing a constant self-oxidation-reduction reaction. Free palladium ions are deposited in the circulation piping and tank, shortening the tank's service life.

[0004] To improve the uniformity of the palladium coating, one approach is to use an N2 bubbling device to increase the uniformity of the flow field within the tank. However, the N2 bubbling tube and bracket installed inside the tank accelerates precipitation, further degrading the yield. Precipitation in the tank requires the bath to be rebuilt, increasing production costs and labor burden. Utility Model Content

[0005] The Summary of the Utility Model introduces a series of simplified concepts that will be further described in the Detailed Description of the Utility Model. The Summary of the Utility Model of the Utility Model does not intend to limit the key features and essential technical features of the claimed technical solution, nor does it intend to determine the scope of protection of the claimed technical solution.

[0006] In view of the existing problems, the utility model provides a wafer palladium plating device, which includes a first tank body, a second tank body, a circulation pipeline and a gas-liquid mixing device; wherein,

[0007] The first tank is used to contain a palladium solution for palladium plating on the wafer;

[0008] The second tank body is used to receive the palladium solution overflowing from the first tank body;

[0009] The circulation pipeline includes a liquid inlet and a liquid outlet, the liquid inlet is connected to the second tank body, the liquid outlet is connected to the first tank body, and the circulation pipeline is used to return the palladium solution in the second tank body to the first tank body;

[0010] The gas-liquid mixing device is arranged on the circulation pipeline and is used to mix the palladium solution from the second tank with the gas.

[0011] Exemplarily, the gas-liquid mixing device includes a gas-liquid mixing chamber and an air-inflating structure arranged in the gas-liquid mixing chamber; wherein,

[0012] The gas-liquid mixing chamber includes a liquid inlet and a liquid outlet, and the circulation pipeline includes a first section of the circulation pipeline and a second section of the circulation pipeline. The first section of the circulation pipeline is connected to the liquid inlet and the second tank body, and is used to transport the palladium solution from the second tank body to the gas-liquid mixing chamber. The second section of the circulation pipeline is connected to the liquid outlet and the first tank body, and is used to transport the palladium solution mixed with the gas to the first tank body.

[0013] The air-inflating structure is connected to a gas pipeline, and the gas pipeline is used to transport gas to the air-inflating structure. The air-inflating structure is provided with at least one air-inflating port, and the air-inflating port is used to inflate air into the gas-liquid mixing chamber.

[0014] Exemplarily, a gas flow controller is provided on the gas pipeline for controlling the flow of gas delivered to the gas-liquid mixing device.

[0015] Exemplarily, the gas flow controller comprises a gas mass flow controller.

[0016] Exemplarily, it also includes a time relay connected to the gas flow controller, which closes when receiving a signal that the previous process is completed to trigger the gas flow controller to deliver gas to the gas-liquid mixing device, and disconnects after closing for a preset time to trigger the gas flow controller to stop delivering gas to the gas-liquid mixing device.

[0017] Exemplarily, it also includes a first switching element connected to the time relay, which closes when receiving a wafer palladium plating signal, so that the time relay can receive a signal indicating the end of the previous process, and opens when not receiving a wafer palladium plating signal, so that the time relay cannot receive a signal indicating the end of the previous process.

[0018] Exemplarily, it also includes a second switching element connected to the power supply of the gas flow controller. The second switching element is closed when a wafer palladium plating signal is received to supply power to the gas flow controller, and is disconnected when a wafer palladium plating signal is not received to cut off the power to the gas flow controller.

[0019] Exemplarily, there is a height difference between the top of the first trough body and the top of the second trough body, so that the palladium solution overflows from the top of the first trough body to the second trough body.

[0020] For example, the circulation pipeline is also provided with a circulation pump, a heater and a filter.

[0021] According to the wafer palladium plating device of the embodiment of the present application, the uniformity of the flow field in the tank body can be improved, thereby improving the palladium plating effect, and it can also reduce the palladium precipitation in the tank body, thereby increasing the service life of the device and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The following drawings of the present invention are used as a part of the present invention for understanding the present invention. The drawings show embodiments of the present invention and their descriptions, and are used to explain the principle of the present invention.

[0023] Figure 1 A schematic diagram of a wafer palladium plating device according to an embodiment of the present invention is shown;

[0024] Figure 2 A schematic diagram of a gas-liquid mixing device according to an embodiment of the present invention is shown;

[0025] Figure 3 A control principle diagram of a gas flow controller according to an embodiment of the present invention is shown;

[0026] Figure 4 The figure shows a control circuit diagram of a gas flow controller according to an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In the following description, numerous specific details are provided to provide a more thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention can be practiced without one or more of these details. In other instances, certain technical features known in the art are not described to avoid confusion with the present invention.

[0028] It should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to make the disclosure thorough and complete and to fully convey the scope of the present invention to those skilled in the art. In the accompanying drawings, the dimensions and relative sizes of layers and regions may be exaggerated for clarity. Like reference numerals throughout represent like elements.

[0029] It should be understood that when an element or layer is referred to as being "on," "adjacent to," "connected to," or "coupled to" another element or layer, it may be directly on, adjacent to, connected to, or coupled to the other element or layer, or there may be intervening elements or layers. Conversely, when an element is referred to as being "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" another element or layer, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers, and / or parts, these elements, components, regions, layers, and / or parts should not be limited by these terms. These terms are merely used to distinguish one element, component, region, layer, or part from another element, component, region, layer, or part. Therefore, without departing from the teachings of the present invention, the first element, component, region, layer, or part discussed below may be represented as a second element, component, region, layer, or part.

[0030] Spatially relative terms such as "under," "beneath," "below," "under," "above," "above," etc., may be used herein for convenience of description to describe the relationship of one element or feature shown in the figures to other elements or features. It should be understood that the spatially relative terms are intended to include different orientations of the device in use and operation in addition to the orientations shown in the figures. For example, if the device in the drawings is flipped, then the elements or features described as "under" or "beneath" or "beneath" the other elements will be oriented as "over" the other elements or features. Thus, the exemplary terms "under" and "under" may include both the upper and lower orientations. The device may be oriented otherwise (rotated 90 degrees or in other orientations) and the spatial descriptors used herein are interpreted accordingly.

[0031] The purpose of the terms used herein is only to describe specific embodiments and is not intended to limit the present invention. When used herein, the singular forms "a", "an" and "the" are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "comprising" and / or "including", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0032] In order to fully understand the present invention, detailed steps and structures will be provided in the following description to illustrate the technical solution proposed by the present invention. The preferred embodiments of the present invention are described in detail below. However, in addition to these detailed descriptions, the present invention may also have other implementation methods.

[0033] Reference below Figure 1-Figure 4 A wafer palladium plating apparatus 100 according to one embodiment of the present application is described.

[0034] like Figure 1 As shown, the wafer palladium plating apparatus according to an embodiment of the present invention includes a first tank 101, a second tank 102, a circulation pipeline 103, and a gas-liquid mixing device 104. The first tank 101 is used to contain a palladium solution for palladium plating on wafers; the second tank 102 is used to receive the palladium solution overflowing from the first tank 101; the circulation pipeline 103 connects the first and second tanks 101, 102, and is used to reflux the palladium solution in the second tank 102 back to the first tank 102; the gas-liquid mixing device 104 is disposed on the circulation pipeline 103 and is used to mix the palladium solution in the circulation pipeline 103 with a gas. The gas mixed with the palladium solution is generally an inert gas, preferably highly clean nitrogen.

[0035] For example, the volume of the first tank body 101 is larger than that of the second tank body 102, and the wafer can be placed in the palladium solution in the first tank body 101 for palladium plating. By providing the second tank body 102, the palladium solution can circulate between the first tank body 101 and the second tank body 102.

[0036] Exemplarily, the first tank body 101 and the second tank body 102 are arranged adjacent to each other, and the second tank body 102 can be arranged in a ring around the first tank body 101, or can be arranged adjacent to one side of the first tank body 101. When the volume of the palladium solution in the first tank body 101 is greater than the capacity of the first tank body 101, the palladium solution in the first tank body 101 will overflow into the second tank body 102 and flow back into the first tank body 101 through the circulation pipeline 103 connecting the first tank body 101 and the second tank body 102, thereby realizing the circulation of the palladium solution between the first tank body 101 and the second tank body 102, so that the palladium solution in the first tank body 101 is always maintained at a set liquid level.

[0037] The circulation line 103 is also equipped with a gas-liquid mixing device 104, which is used to mix the palladium solution in the circulation line 103 with the gas, thereby improving the flow field within the first tank body 101 and improving the uniformity of the palladium coating on the wafers. Because the palladium solution and the gas mix before entering the first tank body 101, there is no need to install a bubbling tube in the first tank body 101. This also prevents palladium precipitation on the surface of the bubbling tube, extending the life of the first tank body 101 and reducing production costs. For example, the gas-liquid mixing device 104 is located near the first tank body 101 to enhance the effect of improving the flow field within the first tank body 101.

[0038] For example, Figure 2As shown, the gas-liquid mixing device 104 includes a gas-liquid mixing chamber 1041, which is provided with a liquid inlet 1042 and a liquid outlet 1043. The liquid inlet 1042 and the liquid outlet 1043 are respectively connected to the circulation pipeline 103. Specifically, the circulation pipeline 103 includes a first section of the circulation pipeline and a second section of the circulation pipeline. The first section of the circulation pipeline connects the liquid inlet 1042 and the second tank body 102, and is used to transport the palladium solution from the second tank body 102 to the gas-liquid mixing chamber 1041. The second section of the circulation pipeline connects the liquid outlet 1043 and the first tank body 101, and is used to transport the palladium solution mixed with the gas to the first tank body 101.

[0039] A gas-liquid mixing chamber 1041 is provided with a gas-inflating structure 1044, which is connected to a gas pipeline 1046 for delivering gas to the gas-inflating structure 1044. The gas-inflating structure 1044 is provided with at least one gas-inflating port 1045, which is used to inject gas into the gas-liquid mixing chamber 1041. This ensures that the gas and the palladium solution are fully mixed before entering the first tank body 101, thereby improving the flow field within the tank and enhancing the uniformity of the palladium coating on the wafer surface. The gas mixed with the palladium solution includes, but is not limited to, nitrogen.

[0040] exist Figure 2 In the example, the gas-liquid mixing chamber 1041 is in the shape of a cube, with the liquid inlet 1042 and the liquid outlet 1043 arranged on the first and second opposite surfaces of the cube, the air inlet arranged on the third surface perpendicular to the first and second surfaces, and the gas pipeline 1046 passing through the air inlet and communicating with the air blowing structure 1044. The air blowing structure 1044 is a rectangular air blowing tube, with multiple air blowing ports 1045 evenly distributed on the air blowing structure 1044 to ensure uniform mixing of the gas and the palladium solution. It should be noted that Figure 2 The gas-liquid mixing device shown is only an example. The gas-liquid mixing chamber 1041 and the inflation structure 1044 can be set to any other suitable shape, and the positions of the liquid inlet 1042, the liquid outlet 1043 and the air inlet can also be set according to actual needs.

[0041] Furthermore, a gas flow controller 105 is provided on the gas pipeline 1046 for controlling the flow of gas delivered to the gas-liquid mixing device 104. Exemplarily, the gas flow controller 105 is a gas mass flow controller (MFC). The gas mass flow controller includes a circuit board, a sensor, an inlet and outlet gas pipe joint, a diverter channel, a regulating valve, etc. After the gas enters the MFC, most of the flow flows through the diverter channel, and a very small part enters the capillary steel tube inside the sensor. The structure of the diverter channel can achieve proportional management of the two parts of gas flow. After the sensor is preheated, the temperature inside it is higher than the temperature of the incoming air flow. At this time, the mass flow of this small part of gas is measured by heat transfer in the capillary steel tube and the principle of temperature difference calorimetry. The gas flow measured in this way can ignore the influence of temperature and pressure. The flow detection signal measured by the sensor is input into the circuit board, and output after amplification, thus completing the measurement of the gas mass flow. By adding a PID closed-loop automatic control function to the circuit board, the flow detection signal measured by the sensor is compared with the set signal, and the regulating valve is controlled based on this to make the flow detection signal equal to the set signal, thereby achieving precise control of the gas mass flow rate.

[0042] Automatic control of gas-liquid mixing can be achieved based on MFC. Specifically, Figure 3 As shown, when the wafer's front-end process (e.g., QDR (Quick Dump Rinse) process) is completed, if the wafer is about to undergo a palladium plating process, the MFC is controlled to open in advance. After the palladium plating process is completed, the MFC is controlled to close in a timely manner to prevent palladium precipitation in the first tank 101 due to the cold gas introduced into the gas-liquid mixing device during idle time.

[0043] Figure 4 The control circuit diagram of the gas flow controller 105 is shown. The gas flow controller is connected to a time relay 401. The time relay 401 closes upon receiving a signal indicating the end of the preceding process, triggering the gas flow controller 105 to deliver gas to the gas-liquid mixing device. It opens after a preset closing time, triggering the gas flow controller 105 to stop delivering gas to the gas-liquid mixing device.

[0044] Furthermore, the wafer palladium plating device further includes a first switch element 402 connected to the time relay 401. The first switch element 402 is closed when receiving the wafer palladium plating signal, so that the time relay 401 can receive the signal of the end of the previous process. It is disconnected when not receiving the wafer palladium plating signal, so that the time relay 401 cannot receive the signal of the end of the previous process. In this way, the following can be achieved: Figure 3 The control scheme shown is to automatically start gas supply when receiving the wafer palladium plating signal and the signal of the end of the previous process, and automatically stop gas supply after the timing ends; if there is no wafer palladium plating signal, no gas supply is performed.

[0045] In some embodiments, the wafer palladium plating apparatus further includes a second switch element 403 connected to a power source of the gas flow controller 105. The second switch element 403 closes upon receiving a wafer palladium plating signal, powering the gas flow controller 105. At this time, gas flow controller 105 begins to deliver gas upon receiving a trigger signal. The second switch element 403 opens upon not receiving a wafer palladium plating signal, powering off the gas flow controller 105. In this case, the gas flow controller 105 is unable to deliver gas.

[0046] Exemplarily, the circulation line 103 is further provided with a pump 106, a heater 107, and a filter 108. The pump 106 is used to provide circulation power from the second tank 102 to the first tank 101, the heater 107 is used to heat the palladium solution to a set temperature, and the filter 108 is used to remove solid impurities in the palladium solution to prevent the solid impurities from adhering to the wafer surface, thereby improving the palladium plating effect.

[0047] In summary, the wafer palladium plating device according to the embodiment of the present invention has the following advantages:

[0048] A new piping structure design is adopted to achieve no physical contact in the first tank, which not only effectively improves the flow field in the first tank, but also avoids the accumulation of precipitates in the tank, prolongs the life of the wafer palladium plating device, and reduces production costs;

[0049] Circuit design enables real-time monitoring of gas-liquid mixing, thus avoiding palladium precipitation in the first tank caused by the introduction of cold gas during idle time.

[0050] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely illustrative and are not intended to limit the scope of the present application. Various changes and modifications may be made therein by those skilled in the art without departing from the scope and spirit of the present application. All such changes and modifications are intended to be included within the scope of the present application as required by the appended claims.

[0051] Similarly, it should be understood that in order to streamline the present application and aid in understanding one or more of the various application aspects, in the description of the exemplary embodiments of the present application, the various features of the present application are sometimes grouped together into a single embodiment, figure, or description thereof. However, this approach of the present application should not be interpreted as reflecting the intention that the claimed application requires more features than those explicitly recited in each claim. More precisely, as reflected in the corresponding claims, the point of the application is that the corresponding technical problem can be solved with fewer features than all the features of a single disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into the detailed description, with each claim itself serving as a separate embodiment of the present application.

[0052] Furthermore, those skilled in the art will appreciate that although some embodiments described herein include certain features included in other embodiments but not other features, combinations of features from different embodiments are intended to be within the scope of this application and to form different embodiments. For example, in the claims, any of the claimed embodiments may be used in any combination.

[0053] It should be noted that the above embodiments are illustrative rather than limiting of the present application, and that those skilled in the art may devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The use of the words first, second, and third, etc., does not denote any order. These words may be interpreted as designations.

Claims

1. A wafer palladium plating device, characterized in that: The wafer palladium plating device includes a first tank body, a second tank body, a circulation pipeline and a gas-liquid mixing device; wherein, The first tank is used to contain a palladium solution for palladium plating on the wafer; The second tank body is used to receive the palladium solution overflowing from the first tank body; The circulation pipeline includes a liquid inlet and a liquid outlet, the liquid inlet is connected to the second tank body, the liquid outlet is connected to the first tank body, and the circulation pipeline is used to return the palladium solution in the second tank body to the first tank body; The gas-liquid mixing device is arranged on the circulation pipeline and is used to mix the palladium solution from the second tank with the gas.

2. The wafer palladium plating device according to claim 1, wherein: The gas-liquid mixing device includes a gas-liquid mixing chamber and an air-inflating structure arranged in the gas-liquid mixing chamber; wherein, The gas-liquid mixing chamber includes a liquid inlet and a liquid outlet, and the circulation pipeline includes a first section of the circulation pipeline and a second section of the circulation pipeline. The first section of the circulation pipeline is connected to the liquid inlet and the second tank body, and is used to transport the palladium solution from the second tank body to the gas-liquid mixing chamber. The second section of the circulation pipeline is connected to the liquid outlet and the first tank body, and is used to transport the palladium solution mixed with the gas to the first tank body. The air-inflating structure is connected to a gas pipeline, and the gas pipeline is used to transport gas to the air-inflating structure. The air-inflating structure is provided with at least one air-inflating port, and the air-inflating port is used to inflate air into the gas-liquid mixing chamber.

3. The wafer palladium plating device according to claim 2, wherein: The gas pipeline is provided with a gas flow controller for controlling the flow of the gas delivered to the gas-liquid mixing device.

4. The wafer palladium plating device according to claim 3, wherein: The gas flow controller includes a gas mass flow controller.

5. The wafer palladium plating device according to claim 3 or 4, wherein: It also includes a time relay connected to the gas flow controller, which closes when receiving a signal that the previous process is completed to trigger the gas flow controller to deliver gas to the gas-liquid mixing device, and disconnects after closing for a preset time to trigger the gas flow controller to stop delivering gas to the gas-liquid mixing device.

6. The wafer palladium plating device according to claim 5, characterized in that: It also includes a first switching element connected to the time relay, which closes when receiving a wafer palladium plating signal, allowing the time relay to receive a signal indicating the end of the previous process, and opens when not receiving a wafer palladium plating signal, preventing the time relay from receiving a signal indicating the end of the previous process.

7. The wafer palladium plating device according to claim 3 or 4, characterized in that: It also includes a second switching element connected to the power supply of the gas flow controller. The second switching element is closed when a wafer palladium plating signal is received to supply power to the gas flow controller, and is disconnected when a wafer palladium plating signal is not received to cut off the power to the gas flow controller.

8. The wafer palladium plating device according to claim 1, wherein: The first trough body and the second trough body are adjacently arranged and attached to each other, and the palladium solution overflows from the top of the first trough body to the second trough body.

9. The wafer palladium plating device according to claim 1, wherein: The circulation pipeline is also provided with a circulation pump, a heater and a filter.

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