A substrate immersion current synchronous triggering system and method for electroplating process

Abstract

This invention provides a substrate immersion current synchronous triggering system and method for electroplating processes. The system includes a host controller, a power supply, a plating head, an electroplating tank, and a direct-switch module. The direct-switch module and the host controller are connected in parallel to form a two-stage control architecture. The direct-switch module includes a contact detection unit, a triggering unit, and an execution unit. The contact detection unit detects the instant the substrate contacts the electroplating solution and outputs a switching signal. The triggering unit generates and transmits a hardware trigger signal within microseconds. The execution unit controls the power supply to output a preset dynamic current during substrate immersion. This invention eliminates system delay through a hardware-level instantaneous triggering mechanism, ensuring that the current application is synchronized with the substrate immersion, avoiding seed layer corrosion, and improving plating uniformity and process repeatability.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing and precision electroplating equipment, and more specifically, to a substrate liquid immersion current synchronous triggering system and method for electroplating processes. Background Technology

[0002] In the electroplating process of advanced semiconductor interconnect technology, an inclined immersion method is usually used to avoid air bubbles adhering when the plating head is immersed in the electroplating solution. However, this inclined immersion method results in different areas of the substrate surface coming into contact with the electroplating solution at different times, which can easily cause problems with plating uniformity.

[0003] In existing technologies, a scheme for dynamically controlling the current during immersion has been proposed to address this problem. This involves adjusting the total current according to the increase in the substrate immersion area to achieve a uniform current density. Such schemes typically rely on a central system controller to uniformly issue control commands. However, this control architecture, based on software scheduling and network communication, has inherent drawbacks: excessively long signal transmission and processing links introduce significant delays.

[0004] This delay makes it difficult to precisely synchronize the power output start-up moment with the physical instant when the substrate actually comes into contact with the solution. This may result in the substrate being partially immersed in the solution but not receiving timely current protection (posing a risk of seed layer corrosion), or the timing of current application not matching the preset immersion area, thereby weakening the effect of dynamic current control and ultimately affecting the uniformity and quality of the coating. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a substrate immersion current synchronous triggering system and method for electroplating processes, which aims to solve the technical problem that the timing of current application is not synchronized with the physical immersion time of the substrate due to the power control signal transmission delay during the tilting immersion process of existing electroplating equipment.

[0006] To achieve the above-mentioned technical effects, the present invention adopts the following technical solution:

[0007] According to a first aspect of the present invention, a substrate immersion current synchronous triggering system for an electroplating process is provided, comprising a host controller, a power supply, a plating head, and an electroplating tank; wherein the plating head includes a substrate clamping device and a plating head lifting mechanism, and further includes a direct-switch module disposed between the power supply and the substrate clamping device; the direct-switch module and the host controller are used to independently control a first electroplating stage and a second electroplating stage; the first electroplating stage refers to the electroplating stage from contact with the electroplating solution to complete immersion in the electroplating solution of an inclined substrate; the second electroplating stage refers to the electroplating stage after the substrate is completely immersed in the electroplating solution.

[0008] The direct-switch module includes a contact detection unit, a triggering unit, and an execution unit. The contact detection unit detects the instant the substrate contacts the electroplating solution and outputs a switching signal to the triggering unit. The triggering unit receives the switching signal and generates a hardware trigger signal within microseconds, transmitting it to the execution unit. The execution unit receives the hardware trigger signal and controls the power supply to output a preset dynamic current, thereby controlling the first electroplating stage.

[0009] The host controller is used to control the power supply to perform electroplating control in the second electroplating stage after the substrate is completely immersed in the electroplating solution.

[0010] In this technical solution, a direct-switch module is constructed through a hardware-level instantaneous triggering mechanism, eliminating the need for software processing and communication with the host controller. The signal detection and current triggering at the moment the substrate enters the liquid are achieved using pure hardware circuitry, significantly reducing software delay and achieving microsecond-level synchronization between substrate contact with the electroplating solution and dynamic current output. At the same time, the electroplating process is divided into a liquid entry dynamic stage and a fully immersed steady-state stage, which are independently controlled by the direct-switch module and the host controller, respectively. This ensures the uniformity of plating deposition during the first liquid entry stage and enables steady-state process control in the second stage through the host controller, thereby improving the overall electroplating synchronization accuracy, process stability, and product yield.

[0011] Optionally, the contact detection unit includes a liquid ingress sensor for real-time detection of the instant of physical contact between the substrate and the electroplating solution, and outputs a switching signal.

[0012] Optionally, the liquid ingress sensor includes: a height sensor, a liquid level impedance sensor, a non-contact capacitive sensor, and an optical liquid level sensor.

[0013] In this technical solution, the instant of contact between the substrate and the electroplating solution is accurately captured and a switching signal is output through sensing methods such as height, impedance, capacitance, and optics. It is compatible with a variety of sensor selections, eliminates detection errors caused by position deviation and environmental interference, avoids missed triggering and false triggering, ensures the accuracy and reliability of contact signal triggering, provides a precise timing reference for subsequent process actions, and improves process stability and processing yield.

[0014] Optionally, when the liquid ingress sensor is a height sensor, the contact detection method includes: detecting the real-time height of the plating head and the tilt angle between the substrate and the electroplating liquid set by the substrate clamping device, and determining the preset height at which the plating head descends when the substrate and the electroplating liquid begin to contact, thereby determining the moment of contact.

[0015] In this technical solution, by detecting the height of the plating head, the tilt angle of the substrate, and the position of the electroplating liquid surface, the contact threshold between the substrate and the electroplating liquid is calculated, and the moment of contact is accurately determined. This eliminates the judgment error caused by the angle and liquid surface fluctuation, making the contact detection accurate and reliable.

[0016] Optionally, the execution unit is connected in series between the power supply and the substrate, and is used to close instantaneously after receiving the hardware trigger signal to connect the preset dynamic current loop.

[0017] In this technical solution, the execution unit string closes instantaneously after receiving the hardware trigger signal, realizing the rapid switching of the preset dynamic current loop. The response speed is synchronized with the hardware trigger signal, ensuring that the switching action of the current loop is precisely matched with the trigger command, thereby improving the timeliness and reliability of system control.

[0018] Optionally, the execution unit may include a solid-state relay based on MOSFET or IGBT.

[0019] Optionally, the parameters of the preset dynamic current include current magnitude, waveform, and duration, which are preset according to the substrate size, immersion speed, and plating head tilt angle.

[0020] In this technical solution, by precisely matching the magnitude, waveform, and duration of the preset dynamic current with the substrate size, immersion speed, and plating head tilt angle, it can match all working conditions of substrate dynamic immersion, effectively avoiding defects such as over-plating, under-plating, and uneven plating, ensuring the uniformity and consistency of plating deposition, and improving the stability of electroplating process and product yield.

[0021] Optionally, the moment when the substrate is fully immersed in the electroplating solution is determined by calculating the tilt angle between the substrate and the electroplating solution and the descent speed of the plating head.

[0022] According to a second aspect of the present invention, a method for synchronously triggering the liquid immersion current of a substrate in an electroplating process is provided, employing the above-described system, comprising the following steps:

[0023] S1: Preparation stage, the electroplating process parameters of the second electroplating stage are programmed to the power supply through the host controller, and the dynamic current parameters of the first electroplating stage are preset in the power supply.

[0024] S2: In the first electroplating stage, the plating head picks up the substrate and tilts it down. When the substrate edge is detected to be in contact with the electroplating solution, the power supply is directly triggered by the through-switch module to output a preset dynamic current to the substrate.

[0025] S3: In the second electroplating stage, after the substrate is fully immersed in the electroplating solution, the direct switch module is disconnected, and the host controller controls the power supply through the communication network to execute the electroplating process of the second electroplating stage, achieving a seamless connection between the two stages.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. This invention uses a direct-switch module to ensure that the power supply outputs a precise dynamic current to the substrate the instant the substrate comes into contact with the electroplating solution, eliminating errors introduced by system delay, thereby significantly improving the uniformity of coating thickness and the consistency of microstructure.

[0028] 2. The hardware triggering path of the through switch module of the present invention is stable and is not affected by factors such as the load of the host computer software or network congestion, and the process repeatability is higher.

[0029] 3. The system provided by this invention can be integrated into existing electroplating equipment as an independent accessory without changing the original main control system architecture, resulting in low upgrade and transformation costs. Attached Figure Description

[0030] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0031] Figure 1 This is a flowchart of the steps of the method described in the second embodiment. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0033] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0034] It should be noted that similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, all directional indications (such as up, down, left, right, front, back, bottom, etc.) in this application are only used to explain the relative positional relationships and movements between components in a specific orientation (as shown in the figures). If the specific orientation changes, the directional indication will also change accordingly. Furthermore, descriptions involving "first," "second," etc., in this application are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated.

[0035] Example 1

[0036] In the electroplating process of advanced semiconductor interconnect technology, the substrate is often immersed in the electroplating solution using an inclined immersion method. During the inclined immersion process, the entire process can be divided into two electroplating stages based on the timing of contact between different areas of the substrate surface and the electroplating solution: the first electroplating stage and the second electroplating stage. The first electroplating stage refers to the period from when the substrate first comes into contact with the liquid surface until it is completely immersed in the electroplating solution. During this stage, the electroplating area of ​​the substrate is constantly changing, which may lead to uneven electroplating. The second electroplating stage refers to the electroplating stage after the substrate is completely immersed in the electroplating solution. During this stage, since the entire substrate is immersed in the electroplating solution, the electroplating contact area is fixed, and the electroplating process is relatively stable.

[0037] This embodiment provides a substrate immersion current synchronous triggering system for electroplating processes, including a host controller, a power supply, a plating head (including a substrate clamping device and a plating head lifting mechanism), an electroplating tank, and a direct-connect switch module disposed between the power supply and the substrate clamping assembly of the plating head. The direct-connect switch module and the host controller form an independently controlled parallel connection, constituting a two-stage switching control architecture, to realize the electroplating control of the first electroplating stage and the second electroplating stage respectively. The direct-connect switch module is used to accurately detect the moment when the substrate contacts the electroplating solution in the first electroplating stage and directly trigger the power supply to output a preset dynamic current. The host controller is used to control the power supply to execute the electroplating control process in the stable stage after the substrate is fully immersed in the electroplating solution in the second electroplating stage.

[0038] The through-switch module includes a contact detection unit, a trigger unit, and an execution unit. The contact detection unit is used to detect the instant when the substrate contacts the electroplating solution and outputs a switch signal to the trigger unit. After receiving the switch signal, the trigger unit generates a hardware trigger signal within microseconds and transmits it to the execution unit. The execution unit is connected in series between the power supply and the substrate and is used to receive the hardware trigger signal and control the power supply to output a preset dynamic current for the first electroplating stage.

[0039] The host controller is used to control the power supply to execute the electroplating process in the stable stage through the communication network after the substrate is fully immersed in the electroplating solution (i.e., the second electroplating stage), thereby realizing the control of the second electroplating stage.

[0040] The aforementioned dual-stage parallel control electroplating architecture breaks the dependence on a single controller, avoids the delay caused by software scheduling and network communication, and achieves precise synchronization between current application and substrate immersion in liquid. This lays the foundation for avoiding seed layer corrosion and improving coating uniformity. Furthermore, it can be integrated into existing equipment as an independent accessory, exhibiting strong compatibility.

[0041] In other possible implementations, the contact detection unit includes a liquid entry sensor, used to detect the instant of physical contact between the substrate and the electroplating solution in real time by detecting a trigger signal, and output a switching signal. The liquid entry sensor includes a (plating head) height sensor, a liquid level impedance sensor, a non-contact capacitive sensor, or an optical level sensor, etc., directly detecting the instant of contact between the wafer substrate and the electroplating solution. Specifically: the (plating head) height sensor detects the instant the plating head descends to the preset contact height based on the real-time height of the plating head, the tilt angle of the substrate, and a preset contact height; the liquid level impedance sensor detects the impedance change signal when the substrate and the electroplating solution form a closed conductive circuit based on their conductivity characteristics; the non-contact capacitive sensor detects the capacitance change signal caused by the change in the dielectric constant of the detection area after the substrate contacts the electroplating solution; the optical level sensor detects the light intensity change signal caused by the change in the light propagation path due to the substrate contacting the liquid surface. Each sensor determines the instant of contact by capturing the step change of the corresponding characteristic physical signal in real time and converts it into a standard switching signal output.

[0042] In a possible implementation, when the liquid ingress sensor is a (plating head) height sensor, the contact detection between the substrate and the electroplating solution can be achieved by detecting the real-time height of the plating head and the tilt angle between the substrate and the electroplating solution set by the substrate clamping device, and determining the preset height at which the plating head descends when the substrate and the electroplating solution begin to contact, thereby determining the moment of contact. Specifically: First, the substrate is raised and lowered by the plating head, with a one-to-one correspondence between the plating head height and the substrate's spatial position. The plating head height is determined by a grating or sensor synchronizer that detects the vertical direction of the plating head lifting mechanism. Second, the substrate is held at an angle by a substrate clamping device, resulting in edge-priority contact with the electroplating solution, making it impossible to visually determine the instant of contact. Third, based on the tilt angle between the substrate and the electroplating solution, and the fixed position of the electroplating solution surface, the critical descent height of the plating head can be accurately calculated; this is the plating head height corresponding to the initial contact between the substrate's contact edge and the electroplating solution. Finally, the calculated critical descent height of the plating head is pre-calibrated; this calibrated height is the preset height. When the real-time height of the plating head reaches this preset height, the plating process can begin. Once the substrate and the electroplating solution have made initial contact, the first electroplating stage begins. The duration of the first electroplating stage, i.e., the time from the initial contact between the substrate and the electroplating solution until the substrate is completely immersed in the solution, can be precisely calculated based on the tilt angle between the substrate and the solution and the constant descent speed of the plating head set by the lifting mechanism. Specifically, using the initial contact between the substrate and the solution as the time reference, the vertical descent displacement of the plating head required for the substrate to go from initial contact at the edge to complete immersion is calculated by combining the tilt angle. The time difference is then obtained by the ratio of this descent displacement to the constant descent speed of the plating head. By superimposing this time difference on the initial contact time, the exact moment when the substrate is completely immersed in the solution can be accurately determined, thus entering the second electroplating stage.

[0043] In other possible implementations, after receiving the switching signal generated by the contact detection unit, the trigger unit can generate a hardware trigger signal within microseconds. Specifically, the trigger unit is hardware-connected to the contact detection unit. After receiving the valid switching signal output by the unit, it directly processes and converts the signal through its built-in pure hardware circuitry. The entire process involves no software protocol parsing and no software processing delay, allowing it to directly generate a hardware trigger signal adapted to the execution unit within microseconds, achieving precise linkage at the moment of contact with the substrate and electroplating solution.

[0044] In other possible implementations, the execution unit employs a high-speed, high-reliability power electronic switch, such as a solid-state relay based on MOSFET or IGBT, connected in series between the power supply and the substrate. Under normal conditions, it remains in an open state, keeping the preset dynamic current loop in an open state. It can accurately receive the hardware trigger signal output by the trigger unit and achieve instantaneous closing based on its high-speed switching characteristics without mechanical contacts. There is no mechanical action delay, and it can quickly connect the preset dynamic current loop the instant the substrate comes into contact with the electroplating solution, ensuring that the electroplating power supply outputs the preset parameter dynamic current to the substrate in a timely manner.

[0045] In other possible implementations, the parameters of the preset dynamic current include current magnitude, waveform, and duration. Each parameter is preset based on the actual working conditions of the electroplating process, combined with the substrate size, immersion speed, and plating head tilt angle. Specifically: the current magnitude is adapted to the effective plating area of ​​the substrate. The larger the substrate size and the faster the immersion speed, the larger the effective plating area of ​​the substrate. To ensure uniform plating deposition rate and consistent plating thickness, the matching current magnitude is correspondingly increased. The faster the immersion speed and the larger the tilt angle, the more rapid the process from initial contact with the edge to complete immersion of the substrate, and the shorter the duration. Furthermore, the larger the tilt angle, the narrower the initial contact area between the substrate and the plating solution. To avoid local under-plating / over-plating caused by instantaneous contact in a narrow area, the current waveform needs to be adapted to a steeper rising edge so that the current quickly reaches the preset value. At the same time, since the overall process time from edge contact with the plating solution to complete immersion of the substrate is shortened, the duration of the current needs to be shortened accordingly to accurately match this dynamic immersion time. By precisely matching the current magnitude, waveform, and duration of the preset dynamic current with the substrate size, immersion speed, and plating head tilt angle, it can match all working conditions of substrate dynamic immersion, effectively avoiding defects such as over-plating, under-plating, and uneven plating, ensuring the uniformity and consistency of plating deposition, and improving the stability of electroplating process and product yield.

[0046] Example 2

[0047] like Figure 1 As shown, this embodiment provides a method for synchronously triggering the substrate immersion current in an electroplating process. It employs the system described in the first embodiment, including: S1, a preparation stage with preset parameters; S2, a first electroplating stage where a direct-switch module triggers the dynamic current at the moment of contact; and S3, a second electroplating stage where, after complete immersion, the process is switched to a host controller to stabilize the process, achieving seamless transition between the two stages.

[0048] S1: Preparation stage, the electroplating process parameters of the stabilization stage, i.e. the second electroplating stage, are programmed to the power supply through the host controller, and the dynamic current parameters of the substrate immersion process, i.e. the first electroplating stage, are preset in the power supply.

[0049] S2: In the first electroplating stage, the plating head tilts and descends while gripping the substrate. When the substrate edge is detected to be in contact with the electroplating solution, the power supply is directly triggered by the through-switch module to output a preset dynamic current to the substrate. Specifically, the contact detection unit detects the moment of contact between the substrate and the electroplating solution in real time. The contact detection unit outputs a switch signal to the trigger unit. The trigger unit generates a hardware trigger signal within microseconds and controls the execution unit to close, causing the power supply to output a preset dynamic current.

[0050] S3: In the second electroplating stage, once the substrate is fully immersed in the electroplating solution, the direct-switch module is disconnected, and the host controller controls the power supply via the communication network to execute the stable-phase electroplating process, achieving a seamless transition between the two stages. The moment when the substrate is fully immersed in the electroplating solution is determined by either the expiration of a preset dynamic current duration or by real-time calculation of the immersion state.

[0051] In this embodiment, the three-stage process achieves seamless integration of dynamic current triggering and stable process control, avoids deviations in the timing of current application, effectively prevents seed layer corrosion, and improves coating uniformity and process repeatability.

[0052] The specific embodiments of the present invention have been described above. Based on the above description, those skilled in the art can make various changes and modifications without departing from the technical concept of the present invention.

Claims

1. A substrate immersion current synchronous triggering system for electroplating processes, comprising a host controller, a power supply, a plating head, and an electroplating tank; wherein, The plating head includes a substrate clamping device and a plating head lifting mechanism, characterized in that it further includes a direct-switch module disposed between the power supply and the substrate clamping device; the direct-switch module and the host controller are used to independently control the first plating stage and the second plating stage of the electroplating process; the first plating stage refers to the plating stage from the time the inclined substrate comes into contact with the plating solution to the time it is completely immersed in the plating solution; the second plating stage refers to the plating stage after the substrate is completely immersed in the plating solution. The direct-switch module includes a contact detection unit, a triggering unit, and an execution unit; wherein, the contact detection unit is used to detect the instant when the substrate contacts the electroplating solution and output a switching signal; the triggering unit is used to receive the switching signal and generate a hardware trigger signal within a microsecond time and transmit it to the execution unit; the execution unit is used to receive the hardware trigger signal and control the power supply to output a preset dynamic current to realize the control of the first electroplating stage; The host controller is used to control the power supply to perform electroplating control in the second electroplating stage after the substrate is completely immersed in the electroplating solution.

2. The system according to claim 1, characterized in that, The contact detection unit includes a liquid ingress sensor, which is used to detect the moment of physical contact between the substrate and the electroplating solution in real time and output a switching signal.

3. The system according to claim 2, characterized in that, The liquid ingress sensor includes: a height sensor, a liquid level impedance sensor, a non-contact capacitive sensor, and an optical liquid level sensor.

4. The system according to claim 3, characterized in that, When the liquid ingress sensor is a height sensor, the contact detection method includes: detecting the real-time height of the plating head and the tilt angle between the substrate and the electroplating liquid set by the substrate clamping device, and determining the preset height at which the plating head descends when the substrate and the electroplating liquid begin to contact, thereby determining the moment of contact.

5. The system according to claim 1, characterized in that, The execution unit is connected in series between the power supply and the substrate, and is used to receive the hardware trigger signal and then close instantaneously to connect the preset dynamic current loop.

6. The system according to claim 1, characterized in that, The execution unit includes a solid-state relay based on MOSFET or IGBT.

7. The system according to claim 1, characterized in that, The parameters of the preset dynamic current include current magnitude, waveform, and duration, which are preset according to the substrate size, immersion speed, and plating head tilt angle.

8. The system according to claim 1, characterized in that, The moment when the substrate is fully immersed in the electroplating solution is determined by calculating the tilt angle between the substrate and the electroplating solution and the descent speed of the plating head.

9. A method for synchronously triggering the liquid immersion current of a substrate in an electroplating process, characterized in that, The system described in any one of claims 1 to 8 comprises the following steps: S1: Preparation stage, the electroplating process parameters of the second electroplating stage are programmed to the power supply through the host controller, and the dynamic current parameters of the first electroplating stage are preset in the power supply. S2: In the first electroplating stage, the plating head picks up the substrate and tilts it down. When the substrate edge is detected to be in contact with the electroplating solution, the power supply is directly triggered by the through-switch module to output a preset dynamic current to the substrate. S3: In the second electroplating stage, after the substrate is fully immersed in the electroplating solution, the direct switch module is disconnected, and the host controller controls the power supply through the communication network to execute the electroplating process of the second electroplating stage, achieving a seamless connection between the two stages.

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