HDI board electroplating equipment

Abstract

The application relates to the field of HDI plate electroplating technology, in particular to an HDI plate electroplating equipment, which comprises an electroplating tank, electrolyte and a copper block arranged in the electroplating tank, and a high-speed power source acting on the electrolyte and the copper block; and an electrolyte flow assembly, which comprises an upper fixed box symmetrically arranged in the electroplating tank, a plurality of first through holes, second through holes and third through holes being vertically arranged on the two sides of the upper fixed box. The bidirectional flow control of the electrolyte flow assembly forms a high-speed turbulent flow of 5-7 m / s in the forward flow stage, significantly improves the electrolyte exchange efficiency at the bottom of the blind hole, stabilizes the copper ion concentration above 80-120 g / L, effectively inhibits the concentration polarization, and removes the residual impurities and bubbles in the hole at a flow rate of 3-5 m / s in the reverse flow stage, cooperates with the injection of the protective agent, and prevents the abnormal thickening of the copper layer at the hole mouth.

Description

Technical Field

[0001] This invention relates to the field of HDI board electroplating technology, and more specifically to an HDI board electroplating equipment. Background Technology

[0002] HDI (High-Density Interconnect) boards, as core components of modern electronic devices, achieve high-density interconnection of multilayer circuits through blind via technology. Unlike traditional through-holes, blind vias only penetrate part of the laminated structure of the circuit board (typical aperture 50-100 micrometers, depth-to-aperture ratio approximately 1:1 to 1:2). This design saves space and increases wiring density to 5-8 times that of traditional PCBs, thus being widely used in space-constrained electronic products such as smartphones and smartwatches. However, in the electroplating process, the blind via area often exhibits a "dog bone effect"—the copper layer at the via opening is abnormally thick, while the plating at the bottom is too thin or even nonexistent. During electroplating, the edge of the via opening forms an electric field concentration zone due to structural abrupt changes, with current density reaching 2-3 times that of the bottom region, causing rapid deposition of copper ions at the via opening. Furthermore, the electrolyte flow at the bottom of the via is slow (usually less than 1 m / s), with copper ion concentration below 30 g / L, leading to severe concentration polarization. In addition, accelerators in traditional processes are difficult to penetrate to the bottom of the via, while inhibitors are prone to excessive adsorption at the via opening, further exacerbating the uneven deposition problem. Summary of the Invention

[0003] In view of the above-mentioned shortcomings of the existing technology, the present invention provides an HDI board electroplating equipment that can effectively solve the problem of "dog bone effect" that occurs when performing HDI board electroplating in the existing technology.

[0004] To achieve the above objectives, the present invention is implemented through the following technical solution: This invention provides an HDI board electroplating apparatus, comprising: An electroplating tank, wherein an electrolyte and a copper block are disposed inside the electroplating tank, and a high-speed power supply is applied to the electrolyte and the copper block; An electrolyte flow assembly includes an upper fixed box symmetrically arranged inside an electroplating tank. Multiple first through holes, second through holes, and third through holes are vertically opened on both sides of the upper fixed box. The axis of the first through hole is deflected downwards at a 15° angle to the midline of the length direction of the upper fixed box, and the axis of the third through hole is deflected towards the midline of the length direction of the upper fixed box at a 15° angle. A suction and drainage pump is arranged below the upper fixed box and is connected to a controller. A vibration assembly is used to suspend the HDI board in an upper fixed box for lifting and vibrating.

[0005] Preferably, it also includes a suspension assembly, which includes hanging arms symmetrically arranged on the upper surface of the electroplating tank. A hanging plate is fixedly installed on the lower end surface of the hanging arm. A mounting plate is provided on one side of the hanging plate. The mounting plate and the hanging plate are fixedly connected by screws. The mounting plate is fixedly connected to the upper surface of the upper fixing box.

[0006] Preferably, a lower fixed box is fixedly installed on the lower end face of the upper fixed box. A main water inlet / outlet hole is opened on the lower end face of the upper fixed box. A connecting pipe is fixedly installed on the lower end face of the upper fixed box at the position corresponding to the main water inlet / outlet hole. A flow pipe is connected to the lower end face of the connecting pipe. A flow rate sensor is fixedly installed on the inner wall of the flow pipe. The flow pipe is fixedly connected to a suction / drainage pump. An inlet / outlet pipe is connected to the outer wall of the flow pipe below the suction / drainage pump. A second solenoid valve is fixedly installed on the inner wall of the inlet / outlet pipe. The second solenoid valve is electrically connected to the controller. One end of the inlet / outlet pipe extends through the lower fixed box into the upper fixed box.

[0007] Preferably, a supporting circular frame is slidably installed inside the connecting pipe, filter cotton is slidably installed on the inner wall of the supporting circular frame, a handle is symmetrically installed on the upper end face of the supporting circular frame, and a water outlet groove is opened on the lower end face of the supporting circular frame.

[0008] Preferably, the outer wall of the flow tube is connected to a second connecting tube below the suction and discharge pump, one end of the second connecting tube is connected to a first storage tank, a first solenoid valve is fixedly installed on the inner wall of the second connecting tube, the first storage tank is filled with an accelerator and an inhibitor, and the first solenoid valve is electrically connected to the controller.

[0009] Preferably, a first connecting pipe is connected to the outer wall of the flow tube and below the suction and discharge pump. A third solenoid valve is fixedly installed on the inner wall of the first connecting pipe. The third solenoid valve is electrically connected to the controller. An adsorption device is connected to the first connecting pipe. A second liquid storage tank is fixedly installed on the inner wall of the lower fixed box. A drug dispensing pipe is connected to one side of the second liquid storage tank. A delivery pump is fixedly installed inside the drug dispensing pipe. The delivery pump is electrically connected to the controller. The upper end of the drug dispensing pipe extends to the top of the upper fixed box. The second liquid storage tank is filled with a protective agent.

[0010] Preferably, a telescopic fixing seat is fixedly installed on the upper end face of the upper fixing box, a pull rod is slidably installed on the inner wall of the telescopic fixing seat, the lower end of the pull rod is slidably connected to the inside of the upper fixing box, a vibrator is fixedly installed on the lower end face of the pull rod, a crossbar is fixedly installed on the output end of the vibrator, a fixing plate is symmetrically installed on the lower end face of the crossbar, a fixing block is fixedly installed on the lower end face of the fixing plate, a sliding block is fixedly installed on the lower end face of the fixing plate at the position of the fixing block, a screw is rotatably installed on one side of the fixing block, the screw is threadedly connected to the sliding block, and the vibrator is electrically connected to the controller.

[0011] The technical solution provided by this invention has the following advantages compared with the known prior art: First, the present invention achieves bidirectional flow control of the electrolyte flow component, forming a high-speed turbulent flow of 5-7 m / s during the forward flow stage, which significantly improves the electrolyte exchange efficiency at the bottom of the blind hole, stabilizes the copper ion concentration at 80-120 g / L or higher, and effectively suppresses concentration polarization; during the reverse flow, a flow rate of 3-5 m / s is used to remove residual impurities and bubbles in the hole, and with the injection of a protective agent, abnormal thickening of the copper layer at the hole opening is prevented.

[0012] Secondly, by linking the flow rate sensor with the controller, the current density and electrolyte flow rate are matched in real time. During the forward flow stage, the current density is increased to 4-5 ASD, and the deposition rate at the bottom of the blind hole reaches 0.6 μm / min. During the reverse flow stage, the current density drops to 1-2 ASD, and the protective agent is precisely added simultaneously to form a protective film at the orifice to inhibit chemical corrosion. At the same time, the SPS and PEG stratified penetration mechanism increases the deposition rate at the bottom of the hole by 40% compared to the orifice. With the dual purification of filter cotton and adsorption device, the organic residue concentration of the electrolyte is less than 0.1 ppm, which significantly extends the service life of the electrolyte and improves the overall production efficiency by more than 50%. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0014] Figure 1 This is a three-dimensional structural schematic diagram of the present invention; Figure 2 This is a schematic diagram of the suspension assembly of the present invention; Figure 3 This is a cross-sectional view of the fixing box of the present invention; Figure 4 This is a schematic diagram of the suction and drainage pump of the present invention; Figure 5 This is a cross-sectional view of the connecting pipe of the present invention; Figure 6 This is a schematic diagram of the structure of the vibration component of the present invention.

[0015] Reference numerals: 1. Electroplating tank; 2. Suspension assembly; 201. Hanging arm; 202. Hanging plate; 203. Mounting plate; 204. Screw; 3. Electrolyte flow assembly; 301. Upper fixing box; 302. First through hole; 303. Second through hole; 304. Third through hole; 305. Main inlet / outlet water hole; 306. Lower fixing box; 307. Connecting pipe; 308. Flow pipe; 309. Suction / drainage pump; 310. Inlet / outlet water pipe; 31 1. First connecting pipe; 312. Second connecting pipe; 313. First liquid storage tank; 314. Second liquid storage tank; 315. Supporting circular frame; 316. Handle; 317. Filter cotton; 319. Drug dispensing pipe; 320. Delivery pump; 4. Vibration assembly; 401. Tie rod; 402. Vibrator; 403. Crossbar; 404. Fixing plate; 405. Fixing block; 406. Sliding block; 407. Screw; 408. Telescopic fixing seat. Detailed Implementation

[0016] 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, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0017] The present invention will be further described below with reference to embodiments.

[0018] Example: Refer to Figures 1 to 6 An HDI board electroplating equipment, comprising: Electroplating tank 1 contains an electrolyte and a copper block, as well as a high-speed power supply that acts on the electrolyte and the copper block. The high-speed power supply is a PlatingPowerSystems PPS-5000 model. Electrolyte composition: Copper sulfate (Cu) 2+ 80-120 g / L), sulfuric acid (150-200 g / L), chloride ions (50-80 ppm); Accelerator (SPS) concentration: 2-5 ppm; Inhibitor (PEG) concentration: 100-200 ppm; The electrolyte flow assembly 3 includes an upper fixed box 301 symmetrically arranged inside the electroplating tank 1. Multiple first through holes 302, second through holes 303, and third through holes 304 are vertically formed along both sides of the upper fixed box 301. The axis of the first through hole 302 is inclined downwards at a 15° angle to the midline of the length direction of the upper fixed box 301, and the axis of the third through hole 304 is inclined towards the midline of the length direction of the upper fixed box 301 at a 15° angle (see reference). Figure 3 The first through hole 302 is deflected downward at 15° and the third through hole 304 is deflected upward at 15° to form a counter-current flow to eliminate the vortex dead zone at the bottom of the blind hole). A suction and drainage pump 309 is provided below the upper fixed box 301. The suction and drainage pump 309 is connected to a controller, which is an existing model S7-1500 PLC controller. Vibration component 4 is used to suspend the HDI board in the upper fixed box 301 for lifting and vibrating.

[0019] Reference Figure 2 It also includes a suspension assembly 2, which includes hanging arms 201 symmetrically arranged on the upper surface of the electroplating tank 1. A hanging plate 202 is fixedly installed on the lower surface of the hanging arm 201. A mounting plate 203 is provided on one side of the hanging plate 202. The mounting plate 203 and the hanging plate 202 are fixedly connected by screws 204. The mounting plate 203 is fixedly connected to the upper surface of the upper fixing box 301. The screws 204 can be turned with a screw wrench to separate the mounting plate 203 from the hanging plate 202 and remove the upper fixing box 301 from the inside of the electroplating tank 1 for cleaning.

[0020] Reference Figures 3 to 5 The lower fixing box 306 is fixedly installed on the lower end face of the upper fixing box 301. The upper fixing box 301, the lower fixing box 306 and other structural components are injection molded from polypropylene (PP) or polytetrafluoroethylene (PTFE) with a volume resistivity >10. 15Ω·cm, completely insulated, and only the HDI plate is connected to the cathode circuit through the fixing block 405 of the vibration assembly 4, while other components are completely disconnected from the current loop. The lower end face of the upper fixing box 301 is provided with a main inlet and outlet water hole 305. A connecting pipe 307 is fixedly installed on the lower end face of the upper fixing box 301 at the position corresponding to the main inlet and outlet water hole 305. The lower end face of the connecting pipe 307 is connected to a flow pipe 308. A flow velocity sensor is fixedly installed on the inner wall of the flow pipe 308. The flow velocity sensor uses an existing vortex flow meter. The vortex flow meter determines the flow velocity by measuring the vortex frequency generated when a liquid or gas flows through an object (such as a vortex generator). The vortex frequency is proportional to the flow velocity, and it can reflect changes in the fluid flow direction in real time. The flow pipe 308 is fixedly connected to the suction and discharge pump 309. An inlet and outlet pipe 310 is connected to the outer wall of the flow pipe 308 and below the suction and discharge pump 309. A second solenoid valve is fixedly installed on the inner wall of the inlet and outlet pipe 310, and the second solenoid valve is electrically connected to the controller. One end of the inlet and outlet pipe 310 extends through the lower fixed box 306 into the upper fixed box 301. A support frame 315 is slidably installed inside the connecting pipe 307. Filter cotton 317 is slidably installed on the inner wall of the support frame 315. A handle 316 is symmetrically installed on the upper end face of the support frame 315. After electroplating, by pulling the handle 316, the support frame 315 can be slidably pulled out from inside the connecting pipe 307, allowing the filter cotton 317 to be removed and cleaned. A water outlet is opened on the lower end face of the support frame 315. A second connecting pipe 312 is connected to the outer wall of the flow pipe 308 and below the suction / drain pump 309. One end of the second connecting pipe 312 is connected to a first storage tank 313. A first solenoid valve is fixedly installed on the inner wall of the second connecting pipe 312. The first storage tank 313 is filled with an accelerator and an inhibitor. The accelerator (such as SPS) concentration is 2-5 ppm. When the electrolyte flows in the forward direction, it can preferentially adsorb onto the surface of the HDI plate (especially the bottom of the blind via), reducing the overpotential of copper ion deposition and making the deposition rate of copper ions at the bottom of the blind via 30%-50% faster than at the via opening. The inhibitor (such as PEG) concentration is 100-200 ppm, which inhibits copper deposition in flat areas of the plate surface and forces ions to diffuse into the blind via. The first solenoid valve is electrically connected to the controller. A first connecting pipe 311 is connected to the outer wall of the flow pipe 308 and below the suction / drainage pump 309. A third solenoid valve is fixedly installed on the inner wall of the first connecting pipe 311 and is electrically connected to the controller. An adsorption device is connected to the first connecting pipe 311. A second storage tank 314 is fixedly installed on the inner wall of the lower fixed box 306. A drug delivery pipe 319 is connected to one side of the second storage tank 314. A delivery pump 320 is fixedly installed inside the drug delivery pipe 319 and is electrically connected to the controller. The upper end of the drug delivery pipe 319 extends above the upper fixed box 301. The second storage tank 314 is filled with a protective agent. The protective agent can be an existing copper protective agent (commonly benzotriazole, BTA). Copper protective agent is a key functional additive.During the reverse flow phase of the electrolyte, copper, acting as the anode, may undergo oxidative dissolution (reaction: Cu→Cu, 2+ +2e - The protective agent forms a protective film on the copper surface by adsorption, preventing H+ in the electrolyte from entering the copper. + When corrosive media such as O2 come into contact with the copper substrate, dissolution loss is reduced. During the reverse flow of the electrolyte, unnecessary dissolution of the copper layer at the orifice is reduced, and BTA indirectly reduces the thickness difference between the orifice and the bottom of the orifice.

[0021] Reference Figure 6 A telescopic fixing seat 408 is fixedly installed on the upper end face of the upper fixing box 301. A pull rod 401 is slidably installed on the inner wall of the telescopic fixing seat 408. The lower end of the pull rod 401 is slidably connected to the inside of the upper fixing box 301. A vibrator 402 is fixedly installed inside the lower end face of the pull rod 401. A crossbar 403 is fixedly installed on the output end of the vibrator 402. A fixing plate 404 is symmetrically installed on the lower end face of the crossbar 403. A fixing block 405 is fixedly installed on the lower end face of the fixing plate 404 and at the position of the fixing block 405. A screw 407 is rotatably installed on one side of the fixing block 405. The screw 407 is threadedly connected to the sliding block 406. The vibrator 402 is electrically connected to the controller. The vibrator 402 vibrates the HDI plate at a frequency of 20-50Hz during the flow interval to force out air bubbles in the blind holes and avoid gas accumulation that affects the uniformity of the coating.

[0022] The working principle of this invention is as follows: The operator clamps the HDI board between the fixing block 405 and the sliding block 406. By turning the screw 407, the sliding block 406 is moved towards the HDI board to complete the clamping. The pull rod 401 slides downward between the telescopic fixing seat 408 and the upper fixing box 301 (the pull rod 401 and the telescopic fixing seat 408 are connected by damping). This drives the HDI board to descend into the upper fixing box 301 until it is completely immersed in the electrolyte set inside the upper fixing box 301. The high-speed power supply is turned on, and the voltage generated acts on the copper block (anode) in the electrolyte, causing the copper block to decompose into copper ions, along with Cu in the electrolyte. ²⁺ Driven by the electric field, it moves toward the HDI plate (cathode); It should be noted that the electrolyte contains Cu ²⁺ The concentration needs to be between 80 and 120 g / L, and the temperature should be maintained between 45 and 2℃. 1. Forward Flow: When copper plating is required inside the blind vias of the HDI board, the electrolyte in the electroplating tank 1 is allowed to flow through the inlet / outlet pipe 310, the flow pipe 308, and the connecting pipe 307, and then through the main inlet / outlet hole 305 into the upper fixed box 301 (this is forward flow of the electrolyte). The electrolyte entering the upper fixed box 301 flows within it (at a flow rate of 5-7 m / s) and impacts the HDI board. A flow rate sensor monitors the electrolyte flow rate inside the flow pipe 308 in real time. If the flow rate is ≥5 m / s, the controller maintains the current flow rate. If the flow rate is <5m / s, the controller increases the pump speed of the suction and drainage pump 309 or triggers an alarm (blockage or leakage). The electrolyte entering the upper fixed box 301 will form turbulence with a Reynolds number >5000 at a high flow rate, which will destroy the diffusion boundary layer in the blind hole, squeeze out the old liquid in the hole, and replace it with fresh high-concentration electrolyte (turbulent shear force destroys the bubble adhesion and carries it out from the bottom of the blind hole). Finally, the flowing electrolyte flows back to the electroplating tank 1 through the first through hole 302, the second through hole 303, and the third through hole 304 (the first through hole 302 is inclined downward to compensate for the top flow rate; the third through hole 304 is inclined upward to prevent the electrolyte from stagnating at the bottom). It should be noted that during the forward flow of the electrolyte, the flow rate sensor will detect the direction of the electrolyte flow and generate an electrical signal based on the direction of the flow (forward flow). The controller controls the voltage of the high-speed power supply based on the generated electrical signal, thereby increasing the current density of the high-speed power supply in the electrolyte to 4-5 ASD and accelerating the deposition at the bottom of the pores. It should also be noted that when the flow rate sensor detects the flow direction of the electrolyte in the flow tube 308, it generates an electrical signal based on the flow direction. The controller uses this signal to control the voltage input to the first solenoid valve, causing the first solenoid valve to open (the opening size of the first solenoid valve is proportional to the flow rate of the electrolyte detected by the flow rate sensor in the flow tube 308). The SPS and PEG (accelerator and inhibitor) mixed in proportion in the first storage tank 313 will enter the flow tube 308 through the second connecting pipe 312, and enter the upper fixed box 301 with the flowing electrolyte. The SPS flows into the bottom of the blind hole with the electrolyte and adsorbs on the hole wall, reducing the deposition overpotential (from -0.2V to -0.1-5V), making the deposition rate at the bottom of the hole 40% faster than that at the orifice. The PEG forms a polarization film in the flat area at the orifice, inhibiting the reduction of copper ions and forcing Cu ²⁺ It migrates towards the bottom of the hole, accelerating the copper plating efficiency inside the hole, and then flows into the electroplating tank 1 along with the electrolyte; 2. Reverse Flow: By switching the suction and drainage pump 309 to reverse mode, the electrolyte is driven to flow in the reverse direction along the path of forward flow. This causes the electrolyte in the upper fixed box 301 to flow outward through the flow pipe 308 and the first connecting pipe 311. At this time, the flow rate of the electrolyte driven by the suction and drainage pump 309 is 3-5 m / s. The electrolyte in the electroplating tank 1 will flow back into the upper fixed box 301 through the first through hole 302, the second through hole 303 and the third through hole 304 to form a vortex covering the HDI board surface, removing residual impurities and impacting the surface of the HDI board. Then, it enters the connecting pipe 307 and the flow pipe 308 through the main inlet and outlet water holes 305, and is then drawn out by the suction and drainage pump 309 and discharged through the first connecting pipe 311. It should be noted that during the forward flow of the electrolyte, the flow rate sensor will detect the direction of the electrolyte flow and generate an electrical signal based on the direction of flow (reverse flow). The controller controls the voltage of the high-speed power supply based on the generated electrical signal, thereby increasing the current density of the high-speed power supply in the electrolyte to 1-2 ASD. It should also be noted that when the flow rate sensor detects the flow direction of the electrolyte in the flow tube 308, it generates an electrical signal based on the flow direction. The controller uses this signal to control the voltage input to the third solenoid valve and the delivery pump 320, cutting off the voltage input to the first and second solenoid valves, thus closing them. This causes the second solenoid valve and the delivery pump 320 to open, allowing the delivery pump 320 to draw out the protective agent stored in the second storage tank 314 and discharge it through the dispensing pipe 319 to the top of the upper fixed box 301 (the output power of the delivery pump 320 is proportional to the electrical signal generated by the flow rate sensor detecting the flow rate of the electrolyte in the flow tube 308). The electrolyte flowing into the upper fixed box 301 is then pumped by the suction and discharge pump 309. The electrolyte is transported to the upper fixed box 301 and enters the connecting pipe 307 and flow pipe 308 through the main inlet / outlet hole 305. Then, it flows through the first connecting pipe 311 to the adsorption device through the third solenoid valve opened by the valve core. (The electroplating solution adsorbed by the adsorption device can be returned to the electroplating tank 1 for reuse. The adsorption device can be an existing activated carbon adsorption tower. Through the physical and chemical adsorption of activated carbon (specific surface area 500-1500m² / g), organic additives (such as SPS, PEG) and their decomposition products in the electrolyte are captured.) The protective agent is discharged into the upper fixed box 301 above the upper fixed box 301 and mixed with the electrolyte. The protective agent can prevent the copper layer at the orifice from melting during the electrolyte flow. After the electrolyte with added protective agent flows through the first connecting pipe 311 into the adsorption device, it can remove more than 90% of the protective agent and organic residues. During the flow inside the connecting pipe 307, the filter cotton 317 will filter and intercept copper powder and impurities. In summary, during the forward flow of the electrolyte, adjusting the density of the high-speed current to 4-5 ASD can drive Cu... ²⁺ Rapid reduction occurs inside the blind aperture, increasing the deposition rate to 0.6 μm / min. Combined with the turbulent flow of 5–7 m / s during forward flow, this compresses the diffusion boundary layer and maintains high Cu content at the aperture bottom. ²⁺ Concentration, to avoid concentration polarization; During the reverse flow of the electrolyte, adjusting the density of the high-speed current to 1-2 ASD can reduce the intensity of the electrochemical reaction at the orifice, inhibit the dissolution or over-plating of copper, and, together with the reverse flow rate of the electrolyte of 3-5 m / s, remove the waste liquid (containing SPS and PEG), avoiding contamination of the fresh electrolyte. In addition, the added 0.5-1 ppm protective agent can form a protective film at the blind hole to prevent chemical corrosion at the orifice. Forward turbulence (5-7 m / s) refreshes the electrolyte at the bottom of the blind hole through high-speed liquid flow, maintaining a high copper ion concentration (80-120 g / L) and directly solving the concentration polarization problem; Reverse flow (3-5 m / s) combined with the injection of a protective agent (such as benzotriazole) forms a protective film at the orifice to inhibit copper deposition, specifically addressing the orifice thickening problem caused by electric field concentration. Although SPS and PEG will flow back to electroplating tank 1 with the electrolyte during the forward flow phase, the concentration of additives in the electroplating tank is always maintained within the safe threshold through forced adsorption purification and flow-adsorption dynamic balance control during the reverse flow phase, and will not cause functional pollution. Positive flow phase: The first through-hole 302 (tilted downwards at 15°) forms a directional high-speed jet (5-7 m / s) that impacts the bottom of the blind hole. The jet direction, tilted downwards at 15°, is aligned with the blind hole axis (usually perpendicular to the HDI plate surface), directly penetrating the bottom region of the blind hole and generating turbulence with a Reynolds number (Re) > 5000. This disrupts the diffusion boundary layer ("disrupting the diffusion boundary layer" refers to the electrolyte stagnation layer near the electrode surface, which is approximately 50 μm thick in traditional processes, impacted by high-speed turbulence, thus solving the concentration polarization problem caused by ion diffusion obstruction at the bottom of the electroplated blind hole). During the forward flow stage, the first through-hole directly impacts the bottom of the blind hole with a high-speed jet of 5-7 m / s, compressing the diffusion boundary layer to below 10 μm and forcibly replacing the low-concentration waste liquid with a high-concentration electrolyte (Cu). ²⁺(80-120 g / L), which transforms ion transfer from inefficient diffusion to efficient convection, increasing the copper deposition rate by 3 times (to 0.6 μm / min), while suppressing abnormal copper layer thickening at the orifice, reducing the "dog bone effect" difference from 4.4 times to 1.1 times, achieving a breakthrough in the uniformity of blind hole electroplating. High-speed liquid flow increases the copper ion concentration at the bottom of the blind hole from <30g / L in conventional processes to 80-120g / L, thereby increasing the copper deposition rate; The third through-hole 304 (tilted upwards at 15°) balances the electrolyte distribution in the top area and prevents eddy current retention at the orifice. The upward-tilted jet forms a shear flow parallel to the surface of the HDI board (flow velocity 2-3 m / s), eliminating the electrolyte retention area near the orifice and inhibiting excessive deposition of copper ions at the orifice. The second through hole 303 (vertical direction) serves as a pressure relief channel to regulate fluid pressure distribution and prevent local overpressure or underpressure. Reverse flow phase: The third through-hole 304 (inclined upwards at 15°) forms a vortex flow (3-5 m / s) at the orifice to remove impurities and bubbles; when flowing in the reverse direction, the third through-hole 304 serves as the main inlet, and the upward-inclined jet forms a vortex structure with a diameter of about 1.5 mm at the orifice, with a shear force of up to 200 Pa, which can peel off organic impurities (such as PEG decomposition products) attached to the orifice wall. The first through hole 302 (tilted downwards at 15°) assists in the discharge of waste liquid at the bottom of the blind hole to prevent residue; when flowing in reverse, the first through hole acts as an auxiliary outlet, working in conjunction with the main drainage path to form a Venturi effect, increasing the discharge speed of waste liquid at the bottom of the blind hole. The second through-hole 303 (vertical direction) maintains the pressure balance during the reverse flow stage; during reverse flow, the vertical through-hole ensures uniform pressure within the hole by adjusting the flow distribution. During forward flow, the three sets of through holes form an asymmetric jet, generating turbulence with a Reynolds number (Re) > 5000, which effectively improves the mass transfer efficiency at the bottom of the blind holes. When the flow is reversed, the circulation loop is formed between each through hole and the main inlet and outlet holes. The waste liquid in the hole is quickly discharged through the Venturi effect, and at the same time, the protective agent is injected to form a molecular-level protective film (about 1-2 nm thick) at the hole opening, which inhibits the chemical corrosion and electrochemical deposition of copper. 3. Vibration. During the process of switching the electrolyte flow from forward to reverse, there is an intermittent time period during which the suction and drainage pump 309 will be shut off to stop the electrolyte flow. When the flow rate sensor detects that there is no liquid flow inside the flow tube 308, the controller controls the voltage input to the vibrator 402, so that the output end of the vibrator 402 drives the crossbar 403 to vibrate. The vibrating crossbar 403 will drive the HDI plate clamped between the fixed block 405 and the sliding block 406 to vibrate. The vibrating HDI plate can effectively discharge the air bubbles inside the blind hole, preventing the electrolyte from being unable to effectively enter the blind hole.

[0023] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

Claims

1. An HDI board electroplating equipment, characterized in that, include: Electroplating tank (1), wherein an electrolyte and a copper block are provided inside the electroplating tank (1), and a high-speed power supply acting on the electrolyte and the copper block; An electrolyte flow assembly (3) includes an upper fixed box (301) symmetrically arranged inside an electroplating tank (1). The upper fixed box (301) has multiple first through holes (302), second through holes (303) and third through holes (304) vertically opened on both sides of the upper fixed box (301). The axis of the first through hole (302) is inclined downward at a 15° angle to the midpoint of the length direction of the upper fixed box (301). The axis of the third through hole (304) is inclined towards the midpoint of the length direction of the upper fixed box (301) at a 15° angle. A suction and drainage pump (309) is arranged below the upper fixed box (301). The suction and drainage pump (309) is connected to a controller. Vibration assembly (4), the vibration assembly (4) is used to suspend the HDI board in the upper fixing box (301) for lifting and vibrating; A lower fixed box (306) is fixedly installed on the lower end face of the upper fixed box (301). A main water inlet / outlet hole (305) is opened on the lower end face of the upper fixed box (301). A connecting pipe (307) is fixedly installed on the lower end face of the upper fixed box (301) at the position corresponding to the main water inlet / outlet hole (305). A flow pipe (308) is connected to the lower end face of the connecting pipe (307). A flow rate sensor is fixedly installed on the inner wall of the flow pipe (308). The flow pipe (308) is fixedly connected to a suction / drainage pump (309). An inlet / outlet pipe (310) is connected to the outer wall of the flow pipe (308) below the suction / drainage pump (309). A second solenoid valve is fixedly installed on the inner wall of the inlet / outlet pipe (310). The second solenoid valve is electrically connected to the controller. One end of the inlet / outlet pipe (310) extends through the lower fixed box (306) into the upper fixed box (301). The inner wall of the lower fixed box (306) is fixedly installed with a second liquid storage tank (314), and the second liquid storage tank (314) is filled with a protective agent.

2. The HDI board electroplating equipment according to claim 1, characterized in that, It also includes a suspension assembly (2), which includes hanging arms (201) symmetrically arranged on the upper surface of the electroplating tank (1). A hanging plate (202) is fixedly installed on the lower surface of the hanging arm (201). An installation plate (203) is provided on one side of the hanging plate (202). The installation plate (203) and the hanging plate (202) are fixedly connected by screws (204). The installation plate (203) is fixedly connected to the upper surface of the upper fixing box (301).

3. The HDI board electroplating equipment according to claim 2, characterized in that, A support frame (315) is slidably installed inside the connecting pipe (307), and a filter cotton (317) is slidably installed on the inner wall of the support frame (315). A handle (316) is symmetrically installed on the upper end face of the support frame (315), and a water outlet groove is opened on the lower end face of the support frame (315).

4. The HDI board electroplating equipment according to claim 3, characterized in that, The outer wall of the flow pipe (308) and below the suction and discharge pump (309) is connected to a second connecting pipe (312). One end of the second connecting pipe (312) is connected to a first storage tank (313). A first solenoid valve is fixedly installed on the inner wall of the second connecting pipe (312). The first storage tank (313) is filled with an accelerator and an inhibitor. The first solenoid valve is electrically connected to the controller.

5. The HDI board electroplating equipment according to claim 4, characterized in that, The outer wall of the flow pipe (308) and below the suction and drainage pump (309) is connected to a first connecting pipe (311). A third solenoid valve is fixedly installed on the inner wall of the first connecting pipe (311). The third solenoid valve is electrically connected to the controller. An adsorption device is connected to the first connecting pipe (311). A drug delivery pipe (319) is connected to one side of the second liquid storage tank (314). A delivery pump (320) is fixedly installed inside the drug delivery pipe (319). The delivery pump (320) is electrically connected to the controller. The upper end of the drug delivery pipe (319) extends to the top of the upper fixed box (301).

6. The HDI board electroplating equipment according to claim 1, characterized in that, A telescopic fixing seat (408) is fixedly installed on the upper end face of the upper fixing box (301). A pull rod (401) is slidably installed on the inner wall of the telescopic fixing seat (408). The lower end of the pull rod (401) is slidably connected to the interior of the upper fixing box (301). A vibrator (402) is fixedly installed on the lower end face of the pull rod (401). A crossbar (403) is fixedly installed on the output end of the vibrator (402). A fixing plate (404) is symmetrically installed on the lower end face of the crossbar (403). A fixing block (405) is fixedly installed on the lower end face of the fixing plate (404). A sliding block (406) is fixedly installed on the lower end face of the fixing plate (404) at the position of the fixing block (405). A screw (407) is rotatably installed on one side of the fixing block (405). The screw (407) is threadedly connected to the sliding block (406). The vibrator (402) is electrically connected to the controller.

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