High aspect ratio micropore pulse sudden change current copper filling method and system

Abstract

The invention discloses a high aspect ratio micropore pulse abrupt change current copper filling method and system, and belongs to the technical field of printed circuit board manufacturing, and the method comprises the steps: obtaining micropore structure parameters, and generating a gradient pulse abrupt change current waveform; monitoring a deposition thickness parameter of the orifice of the micropore in real time, and when the deposition thickness parameter exceeds a preset thickness threshold value, activating the reverse peak clipping pulse group; generating a resonant composite sound field in the electroplating bath; detecting the concentration distribution of the additive in the micropores in real time, and generating a dynamic adjusting instruction according to the concentration distribution of the additive; the independent injection rate of the accelerator and the inhibitor is controlled according to the dynamic adjusting instruction; and based on the gradient pulse abrupt change current waveform, the resonant type composite sound field and the dynamic adjusting instruction, the copper filling process is executed till the target deposition parameters are achieved. According to the method, a multi-field coupling mechanism of gradient pulse dynamic peak clipping, composite sound field synergistic mass transfer and additive concentration real-time regulation and control is adopted, and defect-free high-reliability copper filling can be achieved.

Description

Technical Field

[0001] This invention relates to the field of printed circuit board manufacturing technology, and in particular to a method and system for copper filling of high aspect ratio microvias with pulsed sudden current. Background Technology

[0002] High-density interconnect technology in the field of microelectronic packaging requires the fabrication of microvias with an aspect ratio greater than 8 on the substrate, and the creation of vertical conductive channels through copper electroplating. The filling quality of these microvias directly affects the reliability of the circuit.

[0003] Existing technologies mainly employ pulsed reverse electroplating combined with physical stirring. Periodic current reversal suppresses deposits at the orifice, while mechanical stirring promotes electrolyte exchange. Some solutions incorporate ultrasonic assistance to enhance mass transfer in deep holes.

[0004] However, existing technologies with fixed reverse current parameters cannot adapt to micropores with different depth-to-diameter ratios, resulting in insufficient filling at the bottom of the pore or excessive corrosion at the pore opening; mechanical stirring is difficult to form effective convection deep in the micropore, and the imbalance of additive concentration distribution leads to dendrite growth; the range of a single frequency sound field is limited, and it cannot simultaneously solve the problems of bubble retention and mass transfer bottlenecks. Summary of the Invention

[0005] To address the aforementioned issues, this invention provides a method and system for copper filling with high aspect ratio micropore pulsed sudden current. It employs a multi-field coupling mechanism that utilizes gradient pulse dynamic peak clipping, composite acoustic field synergistic mass transfer, and real-time control of additive concentration to achieve defect-free and highly reliable copper filling.

[0006] The above objectives can be achieved through the following approach: A method and system for copper filling with high aspect ratio micropores using pulsed sudden current includes: acquiring micropore structure parameters and preset target deposition parameters; generating a gradient pulsed sudden current waveform based on the micropore structure parameters, the gradient pulsed sudden current waveform including a main pulse group and a reverse peak-clipping pulse group; monitoring the deposition thickness parameter at the micropore opening in real time, and activating the reverse peak-clipping pulse group when the deposition thickness parameter exceeds a preset thickness threshold; generating a resonant composite acoustic field in an electroplating bath, the resonant composite acoustic field including low-frequency vortex acoustic flow and high-frequency cavitation acoustic flow; detecting the additive concentration distribution within the micropores in real time, and generating a dynamic adjustment command based on the additive concentration distribution; controlling the independent injection rate of accelerator and inhibitor according to the dynamic adjustment command; coupling the gradient pulsed sudden current waveform, the resonant composite acoustic field, and the dynamic adjustment command through multi-physics field coupling to form a coordinated control signal and execute the copper filling process until the target deposition parameters are reached.

[0007] Optionally, generating the gradient pulse sudden current waveform includes: calculating the main pulse intensity parameter and the reverse pulse intensity parameter based on the micropore structure parameters; generating a high-amplitude, short-duration positive current pulse based on the main pulse intensity parameter; generating a low-amplitude, long-duration negative current pulse based on the reverse pulse intensity parameter; and combining the positive current pulse and the negative current pulse to form a time-series alternating pulse sequence to obtain the gradient pulse sudden current waveform.

[0008] Optionally, activating the reverse peak clipping pulse group includes: acquiring real-time deposition thickness data through a micropore aperture sensor; comparing the real-time deposition thickness data with a preset thickness threshold; and triggering a negative current pulse in the time-series alternating pulse sequence when the real-time deposition thickness data exceeds the preset thickness threshold to obtain the reverse peak clipping pulse group.

[0009] Optionally, the generation of the resonant composite sound field includes: generating a first frequency band sound wave and a second frequency band sound wave through a preset multi-band piezoelectric array; causing the first frequency band sound wave to form a rotating fluid motion within the micropore to obtain a low-frequency vortex sound flow; causing the second frequency band sound wave to generate a periodic cavitation effect on the wall of the micropore to obtain a high-frequency cavitation sound flow; and obtaining a resonant composite sound field based on the low-frequency vortex sound flow and the high-frequency cavitation sound flow.

[0010] Optionally, the generation of dynamic adjustment instructions includes: using conductivity sensing units arranged at different depths of the micropores to acquire orifice concentration data and orifice bottom concentration data; calculating the concentration difference parameter between the orifice concentration data and the orifice bottom concentration data to obtain the additive concentration distribution; and generating dynamic adjustment instructions based on the additive concentration distribution.

[0011] Optionally, controlling the independent injection rate includes: parsing the dynamic adjustment command to obtain the concentration difference parameter; initiating accelerator compensation injection when the concentration difference parameter exceeds a preset concentration threshold; synchronously initiating inhibitor enhancement injection when the activation of the reverse peak clipping pulse group is detected; and adjusting the fluid delivery rates of the accelerator and inhibitor based on the concentration difference parameter.

[0012] Optionally, the coordinated control signal includes: during the activation of the main pulse group, coordinating the initiation of accelerator compensation injection and low-frequency vortex acoustic flow; during the activation of the reverse peak clipping pulse group, coordinating the initiation of inhibitor enhancement injection and high-frequency cavitation acoustic flow; causing the high-frequency cavitation acoustic flow to generate a cavitation-electrolysis synergistic effect with the negative current pulse.

[0013] Optionally, the cavitation-electrolysis synergistic effect includes: stretching cavitation bubbles in the micropore using a negative current pulse; causing the stretched cavitation bubbles to rupture near the pore wall to generate microjets; and enhancing the electrolytic stripping effect of the protruding parts of the pore wall through the microjets.

[0014] Optionally, the copper filling process includes: based on the coordinated control signal, using low-frequency vortex acoustic flow to drive the additive molecules to migrate in a directional manner; causing the additive molecules to be uniformly adsorbed onto the pore wall within the current pulse cycle, forming a dynamic molecular barrier layer that inhibits the growth of copper dendrites, until the target deposition parameters are achieved.

[0015] Based on the same inventive concept, this invention also provides a high aspect ratio micropore pulsed sudden current copper filling system, the system comprising: a parameter acquisition module for acquiring micropore structure parameters and preset target deposition parameters; a waveform generation module for generating a gradient pulsed sudden current waveform based on the micropore structure parameters, the gradient pulsed sudden current waveform including a main pulse group and a reverse peak clipping pulse group; a thickness monitoring module for real-time monitoring of the deposition thickness parameters at the micropore opening, and activating the reverse peak clipping pulse group when the deposition thickness parameters exceed a preset thickness threshold; a sound field generation module for generating a resonant composite sound field in the electroplating bath, the resonant composite sound field including low-frequency vortex acoustic flow and high-frequency cavitation acoustic flow; a concentration detection module for real-time detection of the additive concentration distribution within the micropores, and generating a dynamic adjustment command based on the additive concentration distribution; an additive control module for controlling the independent injection rate of accelerator and inhibitor according to the dynamic adjustment command; and a multi-field coupling controller for coupling the gradient pulsed sudden current waveform, the resonant composite sound field, and the dynamic adjustment command through multi-physics fields to form a coordinated control signal and execute the copper filling process until the target deposition parameters are reached.

[0016] Compared with the prior art, the present invention has the following advantages: 1. This invention achieves synergistic control of depth-priority deposition and dynamic peak clipping at the orifice through gradient pulse sudden current waveform, effectively balancing the deposition rate differences at different depths of micropores, eliminating filling voids caused by premature orifice closure, and significantly improving the integrity of copper filling.

[0017] 2. The resonant composite sound field of this invention simultaneously generates low-frequency vortex migration and high-frequency cavitation cleaning effects, which force the renewal of electrolyte in deep hole areas and remove impurities adsorbed on the hole walls, overcoming the problem of limited diffusion of additives in traditional electroplating and ensuring uniform activity of micropore deposition at full depth.

[0018] 3. Based on the independent regulation mechanism of accelerator and inhibitor by real-time concentration detection, this invention dynamically compensates for the concentration gradient difference inside the micropores, inhibits dendrite growth at the bottom of the pores, and optimizes the flatness of the coating at the pore opening, thereby achieving a high-density copper-filled structure.

[0019] 4. The multi-physics spatiotemporal coupling technology of this invention enables the current waveform, sound field energy and fluid transport to produce a synergistic enhancement effect, constructing a dynamic molecular barrier layer on the hole wall, simultaneously improving the deposition rate and coating quality, and reducing the difficulty of subsequent surface treatment processes.

[0020] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic flowchart of the high aspect ratio micro-orifice pulsed sudden current copper filling method according to an embodiment of the present invention.

[0023] Figure 2 This is a schematic diagram of a resonant composite sound field according to an embodiment of the present invention.

[0024] Figure 3 This is a schematic diagram illustrating the dynamic control of additive concentration in an embodiment of the present invention.

[0025] Figure 4 This is a schematic diagram of the high aspect ratio micro-orifice pulsed sudden current copper filling system according to an embodiment of the present invention.

[0026] Figure 5 This is an embodiment of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0028] Reference Figure 1 One embodiment of the present invention proposes a copper filling method for high aspect ratio micropores with pulsed sudden current. It adopts a multi-field coupling mechanism of gradient pulse dynamic peak clipping, composite acoustic field synergistic mass transfer, and real-time control of additive concentration, which can achieve defect-free and highly reliable copper filling.

[0029] The method described in this embodiment specifically includes: Obtain micropore structure parameters and preset target deposition parameters; A gradient pulse sudden current waveform is generated based on the micropore structure parameters. The gradient pulse sudden current waveform includes a main pulse group and a reverse clipping pulse group. The deposition thickness parameter at the micropore orifice is monitored in real time. When the deposition thickness parameter exceeds a preset thickness threshold, the reverse peak clipping pulse group is activated. A resonant composite sound field is generated in the electroplating tank, the resonant composite sound field comprising low-frequency vortex sound flow and high-frequency cavitation sound flow; Real-time detection of additive concentration distribution within micropores; generation of dynamic adjustment commands based on additive concentration distribution. The independent injection rates of the accelerator and inhibitor are controlled according to the dynamic adjustment instructions; The gradient pulse sudden current waveform, resonant composite acoustic field and dynamic adjustment command are coupled in a multi-physics field to form a cooperative control signal and execute the copper filling process until the target deposition parameters are achieved.

[0030] Specifically, a dynamic balance between micropore depth and orifice deposition is achieved through gradient pulse abrupt current waveforms. The main pulse group drives preferential deposition of copper ions in the deep-pore region, while the reverse peak-clipping pulse group selectively activates electrolytic stripping when the orifice deposition is too thick. A resonant composite acoustic field utilizes low-frequency vortex acoustic flow to forcibly renew the electrolyte in the deep pores and promote additive diffusion, while high-frequency cavitation acoustic flow removes adsorbed bubbles and impurities from the pore walls. Real-time monitoring of additive concentration distribution allows for independent adjustment of the accelerator and inhibitor injection rates to compensate for concentration gradient differences within the micropores. Finally, through the spatiotemporal coupling of current waveforms, acoustic field energy, and fluid transport, a dynamic molecular barrier layer is constructed on the pore walls, achieving defect-free copper filling from the bottom up. This method overcomes the diffusion limitations and tip effects of high aspect ratio micropore electroplating, ensuring uniform copper deposition in the depth direction. It effectively eliminates void defects caused by premature orifice closure and inhibits dendrite growth at the bottom of the pore due to insufficient additive concentration. The synergistic effect of multiple fields significantly improves the density and bonding strength of the coating while reducing surface roughness, providing highly reliable copper filling for microelectronic interconnect structures.

[0031] Optionally, the generation of the gradient pulse sudden current waveform includes: Calculate the main pulse intensity parameters and the reverse pulse intensity parameters based on the micropore structure parameters; A high-amplitude, short-duration positive current pulse is generated based on the main pulse intensity parameters; A low-amplitude, long-duration negative current pulse is generated based on the aforementioned reverse pulse intensity parameters; The positive and negative current pulses are combined to form a time-series alternating pulse sequence, resulting in a gradient pulse sudden current waveform.

[0032] Specifically, the micropore structure parameters, including aspect ratio, pore size, and depth, are first obtained. These parameters are directly input into the system using measuring equipment or design data. Then, the main pulse intensity parameter is calculated based on the aspect ratio. ,have: , In the formula, r is the depth-to-diameter ratio, k is a preset current constant in amperes, obtained through experimental calibration, and represents the base current intensity; simultaneously, the reverse pulse intensity parameter is calculated. ,have: , In the formula, This is another preset current constant, measured in amperes, determined experimentally, used to regulate the reverse current; then, a high-amplitude, short-duration forward current pulse is generated based on the main pulse intensity parameter, the amplitude of which is... The pulse width is ,in It is a preset short time value, ranging from 1 millisecond to 10 milliseconds, specifically set based on the micropore diameter; a low-amplitude, long-duration negative current pulse is generated based on the reverse pulse intensity parameter, and the amplitude of this pulse is negative, i.e. The pulse width is ,in It is a preset time value, ranging from 50 milliseconds to 100 milliseconds, and To ensure a more sustained negative effect, the positive and negative current pulses are finally combined to form a time-sequential alternating pulse sequence, specifically by a time controller that sequentially outputs positive pulses continuously. After a certain time, the pulse will switch to a negative pulse duration. The time is used to generate a gradient pulse sudden current waveform by repeating the sequence cyclically. This process is achieved by a current generator to ensure that the pulse sequence alternates continuously on the time axis and the waveform parameters are adjustable in real time.

[0033] Optionally, the activation of the reverse clipping pulse group includes: Real-time deposition thickness data is obtained using a microporous aperture sensor; The real-time deposition thickness data is compared with a preset thickness threshold. When the real-time deposition thickness data exceeds the preset thickness threshold, the negative current pulse in the time-series alternating pulse sequence is triggered to obtain a reverse peak clipping pulse group.

[0034] Specifically, during the electroplating process, a micro-orifice sensor is used to acquire real-time copper deposition thickness data. This sensor uses the principle of optical interference to measure the copper layer thickness on the orifice surface. Then, this real-time deposition thickness data is compared with a preset thickness threshold, which is experimentally set based on the micro-orifice structure parameters. When the real-time deposition thickness data exceeds the preset thickness threshold, the control system triggers the negative current pulse portion of a time-series alternating pulse sequence, resulting in a reverse peak-clipping pulse group. The comparison process utilizes inequalities... ,in This represents real-time deposition thickness data in micrometers, obtained directly from a micropore sensor. This indicates a preset thickness threshold in micrometers, which is pre-input into the system using experimental calibration values ​​for the micropore depth-to-diameter ratio and pore size. This trigger operation is implemented through a digital controller to ensure that the current output is switched immediately when the thickness exceeds the limit.

[0035] Optionally, the generation of the resonant composite sound field includes: The first and second frequency band sound waves are generated by a preset multi-band piezoelectric array. The first frequency band sound wave is made to form a rotating fluid motion in the micropore, resulting in a low frequency vortex acoustic flow; The second frequency band sound wave generates a periodic cavitation effect on the micropore wall, resulting in a high-frequency cavitation acoustic flow; Based on the low-frequency vortex acoustic flow and the high-frequency cavitation acoustic flow, a resonant composite sound field is obtained.

[0036] Specifically, such as Figure 2 As shown, a specific frequency sound wave is generated by a preset multi-band piezoelectric array, which contains two independently controlled piezoelectric transducers; the first set of transducers outputs sound waves at a frequency of... for: , in The velocity constant of the electroplating solution is obtained through actual measurement with a sound velocity meter, and the unit is meters per second. The pore size is measured in meters; the sound wave of this frequency forms a standing wave field within the micropore, inducing rotating fluid motion in the electrolyte, resulting in a low-frequency vortex acoustic flow; the frequency of the sound wave output by the second set of transducers... for: , in The preset harmonic coefficients, ranging from 5 to 8, were determined through experimental optimization. This high-frequency sound wave induces a periodic compression-expansion effect on the microporous wall. When the sound pressure amplitude exceeds the cavitation threshold, a cavitation effect is triggered. (The cavitation threshold is...) ,have: , in For environmental pressure, The surface tension coefficient of the electrolyte. The electrolyte density, These parameters are preset through a physical property database to determine the initial bubble radius; finally, the two sound waves are superimposed in space, and the phase controller causes them to resonate and couple, forming a resonant composite sound field containing low-frequency vortex sound flow and high-frequency cavitation sound flow.

[0037] Optionally, the generation of dynamic adjustment instructions includes: By utilizing conductivity sensing units arranged at different depths of micropores, concentration data at the pore opening and the pore bottom are obtained; Calculate the concentration difference parameter between the orifice concentration data and the orifice bottom concentration data to obtain the additive concentration distribution; Dynamic adjustment instructions are generated based on the additive concentration distribution.

[0038] Specifically, firstly, conductivity sensing units, including orifice sensing units and orifice bottom sensing units, are fixedly installed at different depths in the micropores. The orifice sensing unit measures the conductivity of the electrolyte at the orifice opening in real time, while the orifice bottom sensing unit measures the conductivity of the electrolyte at the orifice bottom in real time. Then, a pre-calibrated conductivity-concentration conversion formula is used to convert the conductivity values ​​into concentration values. For the orifice concentration data... ,have: , In the formula, The calibration coefficient was obtained by calibrating the conductivity of additive solutions of different concentrations in the laboratory. This refers to the conductivity value of the electrolyte at the orifice; for the concentration data at the bottom of the orifice... ,have: , In the formula, The conductivity value of the electrolyte at the bottom of the well is given; then the concentration difference parameter is calculated. ,have: , The concentration difference parameter characterizes the concentration distribution difference of the additive in the direction of micropore depth; finally, a dynamic adjustment command containing the adjustment direction and adjustment amount is generated based on the concentration difference parameter, and an accelerator compensation command is generated when the concentration difference parameter exceeds the preset concentration threshold.

[0039] Optionally, controlling the independent injection rate includes: The concentration difference parameter is obtained by parsing the dynamic adjustment command; When the concentration difference parameter exceeds the preset concentration threshold, the accelerator compensation injection is initiated. When the activation of the reverse clipping pulse group is detected, the inhibitor enhancement injection is initiated simultaneously; The fluid delivery rates of the accelerator and inhibitor are adjusted based on the concentration difference parameter.

[0040] Specifically, such as Figure 3 As shown, the control system first receives a dynamic adjustment command, parses the command to obtain a concentration difference parameter, which characterizes the difference in additive concentration between the bottom and the orifice of the micropore. The concentration difference parameter is compared with a preset concentration threshold. When the concentration difference parameter exceeds the preset threshold, accelerator compensation injection is initiated. The accelerator injection rate is controlled by a proportional control valve. Regarding the accelerator injection rate... ,have: , in The flow rate proportionality coefficient (mL / g·L) was obtained through fluid dynamics experiments. The base injection rate (mL / min) is preset by the process parameters; simultaneously, the activation signal of the reverse peak-shaving pulse group is monitored in real time. When the activation of this pulse group is detected, the inhibitor-enhanced injection is initiated synchronously. Regarding the inhibitor-enhanced injection rate... ,have: , in The inhibitor enhancement coefficient (mL / ms) was determined through pulse period optimization experiments. The width of the negative current pulse (milliseconds). The baseline flow rate for the inhibitor is (mL / min); the final flow rate is calculated in real time. and The values ​​are used to control the precision metering pumps of the accelerator and inhibitor storage tanks respectively, so as to achieve dynamic adjustment of the fluid delivery volume.

[0042] Optionally, the cooperative control signal includes: During the activation of the main pulse group, accelerator compensation injection and low-frequency vortex acoustic flow are initiated in conjunction. During the activation of the reverse clipping pulse group, the inhibitor-enhanced injection and high-frequency cavitation acoustic flow are initiated in tandem. The high-frequency cavitation acoustic flow and the negative current pulse generate a cavitation-electrolysis synergistic effect.

[0043] Specifically, the multi-field coupling controller first receives the activation signal of the gradient pulse abrupt current waveform. When the main pulse group is activated, the controller synchronously outputs the first linkage command, which simultaneously triggers the accelerator compensation injection system and the low-frequency piezoelectric transducer, causing the accelerator to be injected into the electroplating solution at a preset rate, and simultaneously initiating the low-frequency vortex acoustic flow. When the reverse peak clipping pulse group is activated, the controller synchronously outputs the second linkage command, which simultaneously triggers the inhibitor enhancement injection system and the high-frequency piezoelectric transducer, causing the inhibitor to be injected at an enhancement rate, and simultaneously initiating the high-frequency cavitation acoustic flow. During the activation of the reverse pulse group, the phase relationship between the negative current pulse and the high-frequency sound field is precisely matched by the timing controller, and the phase difference between the two is... for: , in The angular frequency of the high-frequency sound wave is determined by the frequency of the sound field; when the phase difference is within the range to At that time, the high-frequency cavitation acoustic flow and the negative current pulse produce a synergistic effect, forming a cavitation-electrolysis synergistic effect.

[0044] Optionally, the cavitation-electrolysis synergistic effect includes: Using negative current pulses to stretch cavitation bubbles within micropores; The stretched cavitation bubbles rupture near the hole wall to generate microjets; The microjet enhances the electrolytic stripping effect on the protruding parts of the pore wall.

[0045] Specifically, during the activation of the reverse clipping pulse group, a negative current pulse is applied to the electrolyte inside the micropore. The cathode electric field generated by this pulse acts on the cavitation bubbles, and the formula for the electric field force is: , in The surface charge of the bubble (coulombs) is obtained by measuring a Zeta potentiometer. The electric field strength (volts / meter) is given by the reverse pulse current density. and electrolyte conductivity Calculated The electric field force causes the bubble to stretch and deform along the direction of the electric field; when the bubble radius is stretched to a critical value, it collapses. For the critical value... ,have: , In the formula, The liquid vapor pressure; at the moment of collapse, microjets with velocities exceeding 100 meters per second are generated near the borehole wall; regarding the impact force of the microjets... ,have: , In the formula, The electrolyte density, The jet velocity; The impact area is determined by the micro-jet impact force applied to the raised parts of the copper plating, which reacts with the electrolytic stripping reaction of the negative current. The synergistic effect causes the passivation film on the raised areas to rupture, accelerating the electrolytic stripping rate. : , in The synergy coefficient was determined through a stripping experiment.

[0046] Optionally, the copper-filling process includes: Based on the aforementioned coordinated control signal, additive molecules are directionally migrated through low-frequency vortex acoustic flow. The additive molecules are uniformly adsorbed onto the pore walls during the current pulse cycle, forming a dynamic molecular barrier layer that inhibits the growth of copper dendrites, until the target deposition parameters are achieved.

[0047] Specifically, after the multi-field coupling controller generates a coordinated control signal, the electroplating solution is driven to rotate through a low-frequency vortex acoustic flow, with a tangential flow velocity... for: ,in The sound flow angular frequency (radians / second) is derived from the low-frequency sound field frequency. Calculated , The micropore radius (meters) is obtained from the micropore structure parameters; this flow field drives the accelerator molecules to migrate tangentially, and the migration rate is... for: , in The molecular mobility coefficient (dimensionless) was calibrated using molecular dynamics simulations; during positive current pulse activation. Inside, additive molecules are uniformly adsorbed onto the pore wall surface during migration, with an adsorption capacity of... ,have: , in The adsorption rate constant (m / s) was determined by a quartz crystal microbalance experiment. The concentration of the additive is (g / L). When the adsorbed molecule coverage reaches a critical value of 0.85, a continuous dynamic molecular barrier layer is formed on the pore wall. The critical value is determined by electrochemical impedance spectroscopy. This barrier layer inhibits abnormal copper ion deposition through steric hindrance effect, and its inhibition energy barrier is [not specified]. for: ,in The steric hindrance coefficient (joules per square meter) is calculated from the molecular size; it suppresses the continued effect of the energy barrier until the deposition thickness reaches the target value.

[0048] Based on the same inventive concept, such as Figure 4 As shown, the present invention also provides a high aspect ratio microvia pulsed sudden current copper filling system, the system comprising: The parameter acquisition module is used to acquire microporous structure parameters and preset target deposition parameters; A waveform generation module is used to generate a gradient pulse sudden current waveform based on the micropore structure parameters. The gradient pulse sudden current waveform includes a main pulse group and a reverse clipping pulse group. The thickness monitoring module is used to monitor the deposition thickness parameters at the micropore opening in real time. When the deposition thickness parameters exceed the preset thickness threshold, the reverse peak clipping pulse group is activated. A sound field generating module is used to generate a resonant composite sound field in an electroplating bath, wherein the resonant composite sound field includes low-frequency vortex sound flow and high-frequency cavitation sound flow. The concentration detection module is used to detect the additive concentration distribution in the micropores in real time and generate dynamic adjustment commands based on the additive concentration distribution. An additive regulation module is used to control the independent injection rates of accelerators and inhibitors according to the dynamic adjustment instructions. A multi-field coupling controller is used to couple the gradient pulse sudden current waveform, the resonant composite acoustic field and the dynamic adjustment command into a multi-physics field to form a coordinated control signal and execute the copper filling process until the target deposition parameters are reached. Example

[0049] To verify the feasibility of this invention in practice, it was applied to the manufacturing of an integrated circuit (IC) packaging substrate. This resulted in the fabrication of microvias with aspect ratios up to 12:1 for next-generation high-density interconnect (HDI) products, achieving high-quality copper filling.

[0050] Currently, the traditional method of pulse reverse electroplating combined with mechanical stirring is used for micropore filling. However, this traditional method faces severe challenges when dealing with micropores with high aspect ratios (greater than 8:1). Problems such as premature closure of the orifice leading to internal voids, copper dendrites at the bottom of the orifice due to insufficient additive delivery, and poor uniformity of the plating thickness often occur, resulting in reduced product yield and insufficient reliability.

[0051] In this embodiment, the system proposed in this invention is used to fill a batch of high aspect ratio microvias with copper. First, the parameter acquisition module acquires the microvia structure parameters (pore diameter 25μm, depth 300μm, aspect ratio 12:1) and target deposition parameters (copper thickness of 20μm after filling). Then, the system initiates a collaborative filling process based on these parameters. The waveform generation module calculates and generates a gradient pulse abrupt current waveform according to the 12:1 aspect ratio, including a high-amplitude, short-duration main pulse group to drive deposition at the bottom of the hole, and a low-amplitude, long-duration reverse pulse group for peak clipping at the hole opening. During the filling process, the thickness monitoring module monitors the copper layer thickness at the hole opening in real time using an optical interferometer sensor. When the thickness exceeds a preset 5μm threshold, the system automatically activates the reverse peak clipping pulse group to electrolytically strip the hole opening, preventing premature closure. Simultaneously, the sound field generation module generates a resonant composite sound field within the electroplating tank. In this process, a low-frequency (e.g., approximately 30 MHz calculated based on the pore size) vortex acoustic current forces the electrolyte to exchange within the 300 μm deep micropores, while a high-frequency (e.g., a sixth harmonic of the low frequency, approximately 180 MHz) cavitation acoustic current removes bubbles and impurities adhering to the pore walls. A concentration detection module monitors the additive concentration gradient in real time using miniature conductivity sensors positioned at the pore opening and bottom. When the concentration difference between the pore bottom and opening exceeds 0.6 g / L, the additive control module immediately initiates accelerator compensation injection; when a reverse clipping pulse is activated, inhibitor injection is simultaneously enhanced. Finally, a multi-field coupling controller coordinates the current waveform, acoustic energy, and additive injection in a spatiotemporal manner to form a unified control signal, achieving efficient and defect-free bottom-up filling.

[0052] To verify the beneficial effects of this invention, 200 test substrates with the same micropore specifications (depth-to-diameter ratio 12:1) were selected and randomly divided into an experimental group and a control group, with 100 substrates in each group. The experimental group was produced using the method of this invention; the control group continued to use the traditional pulse reverse electroplating combined with mechanical stirring method. After filling was completed, the filling quality was detected by cross-section analysis, scanning electron microscopy (SEM), and surface profilometry. The following are the data analysis and effect verification results during the experiment.

[0053] As shown in Table 1, the control group exhibited significant defects in filling quality due to limited diffusion of the additive within the deep pores. Cross-sectional analysis revealed an average void ratio as high as 6.8% in the control group, with most voids located in the middle and bottom of the micropores—a typical characteristic of premature pore closure. In contrast, the experimental group, benefiting from the dynamic suppression of pore deposition by gradient pulsed current and the forced renewal of the electrolyte within the deep pores by low-frequency vortex acoustic flow, achieved near-perfect bottom-up filling, with an average void ratio below 0.5%.

[0054] Table 1. Comparison of Filler Quality (Depth-to-Diameter Ratio 12:1 Micropores)

[0055] As shown in Table 2, regarding coating uniformity and surface quality, the "cavitation-electrolysis synergistic effect" generated by the reverse peak-clipping pulse group and high-frequency cavitation acoustic flow effectively smoothed the copper deposition in the orifice region, with an average surface roughness (Ra) of only 0.18 μm. In contrast, the surface roughness of the control group was as high as 0.45 μm, requiring a longer chemical mechanical polishing (CMP) time to smooth it.

[0056] Table 2 Comparison of Production Efficiency and Surface Quality

[0057] Regarding production efficiency and cost control, as shown in Table 3, the multi-physics synergy of this invention significantly improved the deposition rate. The average time for the experimental group to complete a single filling was 45 minutes, which was 25% shorter than the 60 minutes of the control group. In addition, through real-time monitoring and dynamic control of the additive concentration, the additive consumption of the experimental group was reduced by about 18% compared with the control group, effectively controlling production costs.

[0058] Table 3 Comparison of Resource Consumption and Filling Mode

[0059] As can be seen from the data in Tables 1 to 3 above, the experimental group, after applying the method of this invention, showed significantly better performance in all key indicators compared to the control group. The filling effect is as follows: Figure 5 As shown, the void filling rate decreased from 6.8% to almost zero, proving that this invention effectively solves the core challenge of filling high aspect ratio microvias. Production efficiency increased by 25%, while surface quality was significantly improved, substantially reducing the burden on subsequent processes. Furthermore, the bottom-up filling ratio reached 98.5%, indicating that the multi-field coupling control mechanism of this invention successfully achieved the ideal filling mode, and precise additive control also brought considerable cost savings. These data fully demonstrate the advanced nature, high efficiency, and high reliability of this invention in high aspect ratio microvia copper filling applications.

[0060] It should be noted that the formulas described above, through the principle of dimensional consistency and mathematical standardization methods (such as normalization, dimensionless parameter conversion, or unit system unification), can translate physical quantities with different properties into unitless standard values ​​or parameters that can be superimposed in the same dimension. This eliminates the interference of different dimensions on the computational logic, allowing the formulas to retain the original data distribution characteristics while possessing mathematical rationality and adaptability to objective laws. These are conventional technical methods and will not be elaborated further. The electrical connections between the various units described above do not necessarily represent direct or indirect connections; any indirect connection method is applicable to the embodiments of this invention as long as it achieves the purpose of this invention. The above descriptions are merely exemplary embodiments of this invention and should not be construed as limiting the scope of this invention.

[0061] All equivalent changes and modifications made in accordance with the teachings of this invention are still within the scope of this invention. Those skilled in the art will readily conceive of other embodiments of this invention upon considering the specification and the disclosure of practical truth. This application is intended to cover any variations, uses, or adaptations of this invention that follow the general principles of this invention and include common knowledge or conventional techniques in the art not described herein.

Claims

1. A method for filling high aspect ratio micro-holes with pulsed sudden current copper, characterized in that, The method includes: Obtain micropore structure parameters and preset target deposition parameters; A gradient pulse sudden current waveform is generated based on the micropore structure parameters. The gradient pulse sudden current waveform includes a main pulse group and a reverse clipping pulse group. The deposition thickness parameter at the micropore orifice is monitored in real time. When the deposition thickness parameter exceeds a preset thickness threshold, the reverse peak clipping pulse group is activated. A resonant composite sound field is generated in the electroplating tank, the resonant composite sound field comprising low-frequency vortex sound flow and high-frequency cavitation sound flow; Real-time detection of additive concentration distribution within micropores; generation of dynamic adjustment commands based on additive concentration distribution. The independent injection rates of the accelerator and inhibitor are controlled according to the dynamic adjustment instructions; The gradient pulse sudden current waveform, resonant composite acoustic field and dynamic adjustment command are coupled in a multi-physics field to form a cooperative control signal and execute the copper filling process until the target deposition parameters are achieved.

2. The method for filling high aspect ratio micro-holes with pulsed sudden current copper according to claim 1, characterized in that, The generated gradient pulse sudden current waveform includes: Calculate the main pulse intensity parameters and the reverse pulse intensity parameters based on the micropore structure parameters; A high-amplitude, short-duration positive current pulse is generated based on the main pulse intensity parameters; A low-amplitude, long-duration negative current pulse is generated based on the aforementioned reverse pulse intensity parameters; The positive and negative current pulses are combined to form a time-series alternating pulse sequence, resulting in a gradient pulse sudden current waveform.

3. The method for filling high aspect ratio micro-holes with pulsed sudden current copper according to claim 2, characterized in that, The activated reverse clipping pulse group includes: Real-time deposition thickness data is obtained using a microporous aperture sensor; The real-time deposition thickness data is compared with a preset thickness threshold. When the real-time deposition thickness data exceeds the preset thickness threshold, the negative current pulse in the time-series alternating pulse sequence is triggered to obtain a reverse peak clipping pulse group.

4. The method for filling high aspect ratio micro-holes with pulsed sudden current copper according to claim 1, characterized in that, The generated resonant composite sound field includes: The first and second frequency band sound waves are generated by a preset multi-band piezoelectric array. The first frequency band sound wave is made to form a rotating fluid motion in the micropore, resulting in a low frequency vortex acoustic flow; The second frequency band sound wave generates a periodic cavitation effect on the micropore wall, resulting in a high-frequency cavitation acoustic flow; Based on the low-frequency vortex acoustic flow and the high-frequency cavitation acoustic flow, a resonant composite sound field is obtained.

5. The method for filling high aspect ratio micro-holes with pulsed sudden current copper according to claim 1, characterized in that, The generation of dynamic adjustment instructions includes: By utilizing conductivity sensing units arranged at different depths of micropores, concentration data at the pore opening and the pore bottom are obtained; Calculate the concentration difference parameter between the orifice concentration data and the orifice bottom concentration data to obtain the additive concentration distribution; Dynamic adjustment instructions are generated based on the additive concentration distribution.

6. The method for filling high aspect ratio micro-holes with pulsed sudden current copper according to claim 1, characterized in that, The control of the independent injection rate includes: The concentration difference parameter is obtained by parsing the dynamic adjustment command; When the concentration difference parameter exceeds the preset concentration threshold, the accelerator compensation injection is initiated. When the activation of the reverse clipping pulse group is detected, the inhibitor enhancement injection is initiated simultaneously; The fluid delivery rates of the accelerator and inhibitor are adjusted based on the concentration difference parameter.

7. The method for filling high aspect ratio micro-holes with pulsed sudden current copper according to claim 1, characterized in that, The coordinated control signals include: During the activation of the main pulse group, accelerator compensation injection and low-frequency vortex acoustic flow are initiated in conjunction. During the activation of the reverse clipping pulse group, the inhibitor-enhanced injection and high-frequency cavitation acoustic flow are initiated in tandem. The high-frequency cavitation acoustic flow and the negative current pulse generate a cavitation-electrolysis synergistic effect.

8. The method for filling high aspect ratio micro-holes with pulsed sudden current copper according to claim 1, characterized in that, The cavitation-electrolysis synergistic effect includes: Using negative current pulses to stretch cavitation bubbles within micropores; The stretched cavitation bubbles rupture near the hole wall to generate microjets; The microjet enhances the electrolytic stripping effect on the protruding parts of the pore wall.

9. The method for filling high aspect ratio micro-holes with pulsed sudden current copper according to claim 1, characterized in that, The copper filling process includes: Based on the aforementioned coordinated control signal, additive molecules are directionally migrated through low-frequency vortex acoustic flow. The additive molecules are uniformly adsorbed onto the pore walls during the current pulse cycle, forming a dynamic molecular barrier layer that inhibits the growth of copper dendrites, until the target deposition parameters are achieved.

10. A high aspect ratio microvia pulse-induced current copper filling system, applied to the high aspect ratio microvia pulse-induced current copper filling method as described in any one of claims 1-9, characterized in that, The system includes: The parameter acquisition module is used to acquire microporous structure parameters and preset target deposition parameters; A waveform generation module is used to generate a gradient pulse sudden current waveform based on the micropore structure parameters. The gradient pulse sudden current waveform includes a main pulse group and a reverse clipping pulse group. The thickness monitoring module is used to monitor the deposition thickness parameters at the micropore opening in real time. When the deposition thickness parameters exceed the preset thickness threshold, the reverse peak clipping pulse group is activated. A sound field generating module is used to generate a resonant composite sound field in an electroplating bath, wherein the resonant composite sound field includes low-frequency vortex sound flow and high-frequency cavitation sound flow. The concentration detection module is used to detect the additive concentration distribution in the micropores in real time and generate dynamic adjustment commands based on the additive concentration distribution. An additive regulation module is used to control the independent injection rates of accelerators and inhibitors according to the dynamic adjustment instructions. A multi-field coupling controller is used to couple the gradient pulse sudden current waveform, the resonant composite acoustic field and the dynamic adjustment command into multiple physical fields to form a coordinated control signal and execute the copper filling process until the target deposition parameters are reached.

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