CN112437558A - Blind hole electroplating hole filling method and circuit board - Google Patents
Blind hole electroplating hole filling method and circuit board Download PDFInfo
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- CN112437558A CN112437558A CN202011281749.XA CN202011281749A CN112437558A CN 112437558 A CN112437558 A CN 112437558A CN 202011281749 A CN202011281749 A CN 202011281749A CN 112437558 A CN112437558 A CN 112437558A
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/40—Forming printed elements for providing electric connections to or between printed circuits
- H05K3/42—Plated through-holes or plated via connections
- H05K3/421—Blind plated via connections
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/11—Printed elements for providing electric connections to or between printed circuits
- H05K1/111—Pads for surface mounting, e.g. lay-out
- H05K1/112—Pads for surface mounting, e.g. lay-out directly combined with via connections
- H05K1/113—Via provided in pad; Pad over filled via
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/40—Forming printed elements for providing electric connections to or between printed circuits
- H05K3/42—Plated through-holes or plated via connections
- H05K3/423—Plated through-holes or plated via connections characterised by electroplating method
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
- H05K2201/09—Shape and layout
- H05K2201/09209—Shape and layout details of conductors
- H05K2201/095—Conductive through-holes or vias
- H05K2201/09509—Blind vias, i.e. vias having one side closed
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
- H05K2201/09—Shape and layout
- H05K2201/09209—Shape and layout details of conductors
- H05K2201/095—Conductive through-holes or vias
- H05K2201/0959—Plated through-holes or plated blind vias filled with insulating material
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- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Manufacturing & Machinery (AREA)
- Printing Elements For Providing Electric Connections Between Printed Circuits (AREA)
Abstract
The application provides a blind hole electroplating hole filling method and a circuit board. The blind hole electroplating hole filling method is used for filling the blind holes in the circuit board, and comprises the following steps: immersing the circuit board in a pre-immersion liquid so that the pre-immersion liquid is attached to the inner wall of the blind hole; immersing the circuit board in an electroplating solution, and guiding the electroplating solution around the circuit board to flow, wherein the flowing direction of the electroplating solution is parallel to the axial direction of the through hole of the circuit board; and electroplating the circuit board to enable the blind hole to be filled with a metal column, wherein the exposed end part of the metal column is flush with the surface of the circuit board. The electroplating hole filling method has the advantages of uniform plating layer growth speed on the surface of the circuit board and in the blind holes, high electroplating and hole filling efficiency and good blind hole filling effect.
Description
Technical Field
The invention relates to the field of production and manufacturing of printed circuit boards, in particular to a blind hole electroplating hole filling method and a circuit board.
Background
High Density Interconnect Technology (HDI) is a comprehensive and novel manufacturing Technology for electronic packaging carriers developed to meet the requirements of lighter weight, thinner thickness, fast speed and High frequency development of electronic products and meet the requirements of miniaturization of micro devices and High Density of packaging Technology. In the early 20 th century and the nineties, high-density technology is applied to japan and the usa, and after decades of development, the HDI board has been developed greatly, and particularly, continuous development power is injected into the HDI board due to the pulling of the domestic 3G mobile phone market in recent years.
The electroplating hole filling technology is a process mainly adopted by the high-density interconnection and any layer interconnection technology at present and is the most extensive process used for realizing mass production. In addition, the process of conductive paste and convex copper blocks is adopted, but the electroplating hole filling technology has high reliability and relatively mature process, and the requirement on the integrity of high-frequency and high-speed signals is higher and higher as the function of a lead is changed from a transmission line to a signal line along with the continuous improvement of the wiring density of the PCB.
When the traditional electroplating blind hole filling method is used for filling the blind holes of the circuit board, the following defects exist,
1. because the aperture of the blind hole of circuit board is less, copper ion is located the face of circuit board and the drill way department of blind hole mostly, is difficult for entering into inside the blind hole, therefore the copper ion is far greater than downtheholely at face and periporium's anchorage rate, and the cladding material growth rate of circuit board face is far greater than the cladding material growth rate of blind hole pore wall promptly, finally leads to downthehole appearance cavity, circuit board transmission effect to receive serious influence.
2. In order to avoid the occurrence of voids in the blind holes, a method of reducing current density is generally adopted to reduce the growth rate of the plating layer, so that copper ions have enough time to enter the blind holes, and then the copper ions can be uniformly attached to the hole walls and the board surface, thereby achieving the effect of uniformly increasing the plating layers on the board surface and the hole walls.
3. The filling quality of the blind holes is difficult to control accurately. Because the concentration of copper ions in the blind holes at all positions is different, the growth speed of a hole wall plating layer is not uniform in the electroplating process, and the filling of partial blind holes is often not full, so that the situation of sinking occurs, or the situation that the filling of partial blind holes is over full to form bulges affects the quality of a circuit board.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provides a blind hole electroplating hole filling method and a circuit board, wherein the plating layer on the surface of the circuit board and inside a blind hole is increased at a uniform speed, the electroplating and hole filling efficiency is higher, and the blind hole filling effect is good.
The purpose of the invention is realized by the following technical scheme:
a blind hole electroplating hole filling method is used for filling blind holes on a circuit board and comprises the following steps:
immersing the circuit board in a pre-immersion liquid so that the pre-immersion liquid is attached to the inner wall of the blind hole;
immersing the circuit board into electroplating solution, and guiding the electroplating solution around the circuit board to flow so that the flow direction of the electroplating solution is parallel to the axial direction of the through hole of the circuit board;
and electroplating the circuit board to enable the blind hole to be filled with a metal column, wherein the exposed end part of the metal column is flush with the surface of the circuit board.
In one embodiment, the flow rate of the plating solution is 4cm to 6 cm/s.
In one embodiment, the concentration of the plating accelerator is 25% to 30%.
In one embodiment, the pre-immersion liquid is in a vibration state during immersion of the circuit board in the pre-immersion liquid.
In one embodiment, the temperature of the pre-immersion liquid is 25-30 ℃, and the time for immersing the circuit board in the pre-immersion liquid is 4-5 h.
In one embodiment, the electroplating process of the circuit board comprises a first electroplating process and a second electroplating process, wherein the current density of the first electroplating process is 0.7-0.8 ASD, the electroplating time is 15-20min, the current density of the second electroplating process is 1.4-1.6 ASD, and the electroplating time is 60-90 min.
In one embodiment, the plating solution includes a copper sulfate solution, a plating accelerator, a plating suppressor, and a plating leveler.
A circuit board, wherein the circuit board is provided with a blind hole and a through hole, and the blind hole of the circuit board is filled by adopting the blind hole electroplating hole filling method of any one of claims 1 to 7.
In one embodiment, the circuit board is provided with a through hole, the blind hole is arranged at a position adjacent to the through hole, and the axial direction of the blind hole is parallel to the axial direction of the through hole.
In one embodiment, the circuit board includes a first base layer, a metal conductive layer and a second base layer, the first base layer, the metal conductive layer and the second base layer are sequentially stacked and connected, the blind via sequentially penetrates through the first base layer, the metal conductive layer and the second base layer, the through hole sequentially penetrates through the first base layer, the metal conductive layer and the second base layer, and a portion of the metal conductive layer is exposed in the through hole.
Compared with the prior art, the invention has at least the following advantages:
1. the circuit board is immersed in the pre-immersion liquid containing the electroplating accelerator, so that the blind holes of the circuit board are filled with the pre-immersion liquid, the concentration of the electroplating accelerator at the bottom of the holes and the hole wall is further improved, and the electroplating accelerator has the effect of accelerating the increase speed of a plating layer, so that the generation speeds of the blind holes and the copper plating layer of the board surface are relatively even, the condition that the holes are formed in the holes due to the fact that the plating layers of the board surface and the hole opening are too fast is avoided, the purpose of preventing the holes from being formed in the blind holes can be achieved on the premise that the current density is not required to be reduced, the electroplating time is not required;
2. the electroplating solution on the board surface of the circuit board is led to continuously flow towards the board surface of the circuit board, so that the electroplating solution on the board surface of the circuit board tends to flow towards the through hole and the board edge, namely, the electroplating solution above the blind hole tends to flow towards the through hole or the board edge, and the electroplating solution inside the blind hole tends to flow outwards due to the difference of the flow rates of the electroplating solution above the blind hole and the electroplating solution inside the blind hole, so that the exchange efficiency of the electroplating solution in the blind hole is improved, more copper ions flow into the blind hole, enough copper ions are contained in the blind hole to improve the plating layer growth speed of the blind hole, and the filling effect of the blind;
3. the continuous face towards the circuit board of guide plating solution flows, can effectively improve the inside and outside plating solution exchange efficiency of blind hole for the copper ion homoenergetic of each blind hole keeps in higher concentration range, and then makes the cladding material growth rate of each blind hole comparatively average, has guaranteed to fill effectively to prevent bellied formation under the full prerequisite, improves the quality of circuit board.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
FIG. 1 is a flow chart of a blind via hole filling method in an embodiment;
FIG. 2 is a schematic structural diagram of a circuit board undergoing electroplating via filling by the blind via electroplating via filling method shown in FIG. 1;
FIG. 3 is a schematic structural diagram of a circuit board filled by the blind via electroplating filling method shown in FIG. 1;
fig. 4 is a schematic structural diagram of a plating soaking device of the plating soaking apparatus used in S100 of the blind via plating hole filling method shown in fig. 1;
fig. 5 is a schematic structural view of another view angle of the plating soaking device shown in fig. 4.
Detailed Description
To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not represent the only embodiments.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
As shown in fig. 1 and fig. 2, a blind via electroplating filling method of an embodiment is used for filling a blind via 120 on a circuit board 100, and the blind via electroplating filling method includes the following steps: the circuit board 100 is immersed in the pre-immersion liquid so that the pre-immersion liquid adheres to the inner wall of the blind hole 120. The circuit board 100 is immersed in the plating solution, and the flow of the plating solution around the circuit board 100 is guided in a direction parallel to the axial direction of the through-hole 110 of the circuit board 100. The circuit board 100 is electroplated such that the blind holes 120 are filled with metal pillars, and the exposed ends of the metal pillars are flush with the surface of the circuit board.
Above-mentioned blind hole electroplating filling method, through with in the circuit board 100 dip the preimpregnation liquid that contains the electroplating accelerator, make to be full of the preimpregnation liquid in the blind hole 120 of circuit board 100, and then the electroplating accelerator concentration of hole bottom and pore wall has been improved, the electroplating accelerator has the effect of accelerating cladding material growth rate, consequently, can make the copper coating speed of blind hole 120 and face comparatively average, avoid face and drill way cladding material to generate the condition that speed is too fast and lead to downthehole appearance cavity, can reach the mesh that prevents blind hole 120 appearance cavity under the prerequisite that need not to reduce current density promptly, need not to prolong the length of time of electroplating, make the machining efficiency of circuit board 100 obtain guaranteeing. The electroplating solution on the surface of the circuit board 100 is led to continuously flow towards the surface of the circuit board 100, so that the electroplating solution on the surface of the circuit board 100 tends to flow towards the through hole 110 and the edge of the board, namely, the electroplating solution above the blind hole 120 flows towards the through hole 110 or the edge of the board, and the electroplating solution inside the blind hole 120 tends to flow outwards due to the difference of the flow rates of the electroplating solutions above the blind hole 120 and inside the blind hole 120, so that the exchange efficiency of the electroplating solution inside the blind hole 120 is improved, more copper ions flow into the blind hole 120, enough copper ions are contained in the blind hole 120 to improve the plating speed of the blind hole 120, the filling effect of the blind hole 120 is ensured, meanwhile, the electroplating solution is led to continuously flow towards the surface of the circuit board 100, the exchange efficiency of the electroplating solution inside and outside the blind hole 120 can be effectively improved, and the copper ions, further, the plating layer growth speed of each blind hole 120 is relatively even, the formation of the bulge is effectively prevented on the premise of ensuring full filling, and the quality of the circuit board 100 is improved.
In order to better understand the measurement method of the present invention, the blind via hole filling method of the present invention is further explained below, and the blind via hole filling method of an embodiment is used to fill the blind via 120 on the circuit board 100. The blind hole electroplating hole filling method comprises the following steps:
s100, the circuit board 100 is immersed in a pre-dip solution to make the pre-dip solution adhere to the inner wall of the blind via 120, the pre-dip solution including a plating accelerator. In this embodiment, immerse circuit board 100 in the pre-dip liquid, the dust and the impurity of adhesion on circuit board 100 can be washd off to the pre-dip liquid for the cladding material impurity of circuit board 100 reduces, and then improves the transmission effect of circuit board 100, includes the electroplating accelerator in the pre-dip liquid, and circuit board 100 is before electroplating in the pre-dip liquid, enables blind hole 120 inside to have more electroplating accelerators, and then improves the filling quality of blind hole 120.
S200, the circuit board 100 is immersed in the plating solution, and the flow of the plating solution around the circuit board 100 is guided, the flow direction of the plating solution being parallel to the axial direction of the through-hole 110 of the circuit board 100. In this embodiment, the circuit board 100 is placed in an electroplating bath body filled with an electroplating solution, so that the circuit board 100 is immersed in the electroplating solution, a circulating liquid discharge device is disposed in the electroplating bath, the circulating liquid discharge device includes a plurality of liquid outlets uniformly disposed on a wall of the electroplating bath, the plurality of liquid outlets of the circulating liquid discharge device continuously discharge the electroplating solution to guide the electroplating solution in the electroplating bath to flow, and liquid discharge directions of the plurality of liquid outlets are all opposite to a plate surface of the circuit board 100, so that a flow direction of the electroplating solution discharged from the liquid outlets is perpendicular to the plate surface of the circuit board 100, that is, the flow direction of the electroplating solution is parallel to an.
And S300, electroplating the circuit board 100 to fill the blind holes 120 with metal. In this embodiment, the electroplating apparatus is powered on to start electroplating the circuit board 100, the liquid circulating and draining device continuously operates to continuously guide the electroplating solution to flow toward the board surface of the circuit board 100, and the circuit board 100 completes electroplating in the flowing electroplating solution, so that the blind holes 120 are filled with metal.
Further, compared with the conventional electroplating solution for industrial copper plating, the electroplating solution for electroplating the blind hole 120 of the circuit board further comprises an electroplating accelerator, an electroplating inhibitor and an electroplating leveling agent, wherein the electroplating accelerator is mainly composed of thiol-containing micromolecule substances, and in the electroplating process of the circuit board 100, the electroplating accelerator is mainly concentrated in a low current density area, namely the bottom of the blind hole 120 of the circuit board 100, and the diffusion rate of the electroplating accelerator is high, so that the concentration of the accelerator at the bottom of the blind hole is gradually increased, and the accelerator has the functions of promoting the deposition of copper and refining grains, thereby accelerating the generation speed of the copper plating at the bottom of the blind hole 120. The electroplating leveling agent is a nitrogen-containing group substance, has extremely strong polarity, is easy to absorb in a high current density area, namely a blind hole 120 orifice high potential area of the circuit board 100, and has a positive charge, and the diffusion speed of the electroplating leveling agent is slow relative to that of the electroplating accelerator, so that the concentration of the electroplating leveling agent from the orifice to the hole bottom is gradually reduced, and the electroplating leveling agent can reduce the increase speed of an orifice plating layer, so that the increase speed of the orifice plating layer is lower than that of the hole bottom, and cavities are prevented from occurring in the holes. The electroplating inhibitor is mainly polyether substance, and the electroplating inhibitor is adsorbed on the board surface of the circuit board 100 under the cooperation of chloride ions, so that the growth speed of the copper plating layer on the board surface is reduced, and the growth speeds of the board surface and the plating layer at the bottom of the blind hole 120 can be relatively even.
Further, in order to avoid the occurrence of voids in the blind via 120, a method of reducing current density is usually adopted to reduce the growth rate of the plating layer, so that copper ions have enough time to enter the blind via 120, and then the copper ions can be more uniformly attached to the via wall and the board surface, thereby achieving the effect of uniformly increasing the plating layer on the board surface and the via wall, however, the method greatly prolongs the electroplating time, and reduces the processing efficiency of the circuit board 100. In addition, before the circuit board 100 is electroplated, a plurality of dust and impurities are easily adhered to the circuit board 100 through the processes of drilling, pressing and the like, and if the circuit board 100 is directly placed in the electroplating solution for electroplating, the dust and the impurities on the circuit board 100 are melted into the electroplating solution, so that the plating layer of the circuit board 100 contains the impurities, and the transmission effect of the circuit board 100 is affected. In this embodiment, the circuit board 100 is immersed in the pre-immersion liquid containing the plating accelerator, so that the blind hole 120 of the circuit board 100 is filled with the pre-immersion liquid, and the concentration of the plating accelerator at the bottom and on the wall of the hole is further increased, in the electroplating process, since the plating accelerator attached to the board surface and the hole opening is easily squeezed by the plating inhibitor and the plating leveling agent, and the blind hole 120 has a semi-closed structure relative to the board surface, the plating accelerator in the blind hole 120 can be kept in a high concentration state, and the high concentration plating accelerator can effectively increase the generation speed of the copper plating layer in the blind hole 120, so that the generation speeds of the copper plating layers in the blind hole 120 and the board surface are relatively even, thereby avoiding the occurrence of voids in the hole due to the excessively fast generation speeds of the board surface and the hole opening plating layer, that the purpose of preventing the voids in the blind hole 120 from occurring can be achieved without reducing, so that the processing efficiency of the circuit board 100 is ensured.
Further, because the aperture of the blind hole 120 of the circuit board 100 is small, the copper ions are mostly located on the board surface of the circuit board 100 and the hole opening of the blind hole 120, and are not easy to enter the blind hole 120, so the adhesion speed of the copper ions on the board surface and around the hole is much higher than that in the hole, that is, the plating layer growth speed of the board surface of the circuit board 100 is much higher than that of the hole wall of the blind hole 120, and finally, the hole appears in the hole, and the transmission effect of the circuit board 100 is seriously. In this embodiment, the circuit board 100 is provided with the through hole 110 and the blind hole 120, the liquid circulating device guides the plating solution to continuously flow toward the board surface of the circuit board 100 during the plating process, since the through hole 110 penetrates the circuit board 100, the plating solution will penetrate the current plate from the through hole 110 on one surface of the circuit board 100 and then flow out from the other surface of the circuit board 100, and flow through the edge of the circuit board 100 to the other surface of the circuit board 100, such that the flow rate of the plating solution at the through hole 110 and at the edge of the circuit board 100 is larger, as can be known from bernoulli's principle, the pressure at the position with larger flow rate is smaller, that is, the pressure at the through hole 110 and at the edge of the board is smaller relative to the pressure at the board surface, the fluid will flow from the place with larger pressure to the place with smaller pressure, and therefore, the plating solution at the board surface of the circuit board, due to the difference between the flow rates of the plating solution above the blind hole 120 and inside the blind hole 120, the plating solution inside the blind hole 120 tends to flow out of the hole, so that the exchange efficiency of the plating solution inside the blind hole 120 is improved, more copper ions flow into the blind hole 120, and the plating layer growth rate of the blind hole 120 is increased by enough copper ions in the blind hole 120, thereby ensuring the filling effect of the blind hole 120, and the blind hole 120 is more favorably filled along with the increase of the aperture of the through hole 110.
Further, due to the different concentrations of copper ions in the blind holes 120, the growth rate of the hole wall plating layer is not uniform during the electroplating process, and thus, the blind holes 120 are often partially filled with copper ions to form recesses, or the blind holes 120 are partially filled with copper ions to form protrusions, which affects the quality of the circuit board 100. In this embodiment, in the electroplating process, the continuous plate surface flowing towards the circuit board 100 of plating solution is guided by the circulating liquid discharge device, the exchange efficiency of the plating solution inside and outside the blind holes 120 can be effectively improved, so that the copper ions of the blind holes 120 can be kept in a higher concentration range, and further the plating layer growth speed of the blind holes 120 is relatively even, meanwhile, the time of point reading is controlled, after the blind holes 120 are filled, the flowing electrolyte can enable the copper ions to flow uniformly, so that the ion concentration of the filling part of the blind holes 120 and the plate surface is average, the formation of protrusions is effectively prevented on the premise of ensuring full filling, and the quality of the circuit board 100 is improved.
In one embodiment, the flow rate of the plating solution is 4cm/s to 6 cm/s. The flowing speed of the electroplating solution is an important factor for determining the copper ion exchange efficiency inside and outside the blind hole, when the flow speed of the electroplating solution is insufficient, a sufficient pressure difference cannot be formed, namely, a sufficient flow speed difference cannot be formed, so that the copper ion exchange efficiency inside and outside the blind hole is low, and the plating layer in the blind hole is slow in growth speed due to insufficient copper ions. In this embodiment, the flow rate of the plating solution is 4cm/s to 6cm/s, and in this range, the copper ion exchange efficiency inside and outside the blind via and the plating accelerator concentration inside the blind via are both high, which contributes to maximizing the plating growth rate inside the blind via.
In one embodiment, the concentration of the plating accelerator is 25% to 30%. The concentration of the electroplating accelerator in the pre-immersion liquid is an important factor for determining the growth speed of a copper plating layer in a blind hole, when the concentration of the electroplating accelerator is insufficient, the concentration of the electroplating accelerator immersed in the blind hole of the circuit board in the pre-immersion liquid is insufficient, and then the electroplating accelerator in the blind hole is diluted by the electroplating liquid, so that the effect of obviously increasing the growth speed of the plating layer in the blind hole cannot be achieved, the growth speed of the plating layer on the board surface is greater than the growth speed of the plating layer in the blind hole, and cavities are generated in the blind hole, and when the concentration of the electroplating accelerator in the pre-immersion liquid is too high, the concentration of copper ions is limited, the blind hole of the circuit board cannot completely use the electroplating accelerator with high concentration for the generation of the copper plating layer, namely, the marginal benefit is decreased, so that. In the embodiment, the concentration of the electroplating accelerator in the pre-immersion liquid is 25% -30%, the effect of increasing the growth speed of the coating in the blind hole can be obviously achieved within the concentration range, the economy is better, and the production benefit is more facilitated.
In one embodiment, the pre-immersion liquid is in a vibrating state during immersion of the circuit board in the pre-immersion liquid. In order to improve the soaking effect of circuit board, increase the inside and outside liquid exchange degree of blind hole, and then make the electroplating accelerator in the immersion fluid can get into the blind hole completely, in this embodiment, be provided with the high frequency vibrator in the cell body that holds the immersion fluid in advance, through high frequency vibrator vibrations immersion fluid in advance, make the immersion fluid be the vibration state, the activity degree of the immersion fluid under the vibration state is higher, the immersion fluid gets into in the blind hole more easily, can make the electroplating accelerator in the immersion fluid in advance enter into to the blind hole completely promptly, improve the inside electroplating accelerator concentration of blind hole, and then accelerate the growth rate of the inside copper coating of blind hole, dust or impurity on the circuit board can shake down to the immersion fluid under the vibration state simultaneously, strengthen the clean effect to the circuit board, the impurity of cladding material when reducing electroplating, and then improve the transmission effect.
In one embodiment, the temperature of the pre-immersion liquid is 25-30 ℃, and the time for immersing the circuit board in the pre-immersion liquid is 4-5 h. The temperature of the pre-immersion liquid can influence the viscosity of the pre-immersion liquid, the viscosity is too high or too low to be beneficial to the sufficient immersion of the circuit board, the immersion time is an important factor for determining the immersion effect of the circuit board, the circuit board needs to be immersed for enough time to enable the blind hole to be adhered with the pre-immersion liquid with enough concentration, in the embodiment, the temperature of the pre-immersion liquid is 25-30 ℃, the physical state of the pre-immersion liquid is the most suitable viscosity in the temperature range, the immersion efficiency of the circuit board can be improved, the blind hole of the circuit board is enabled to be fully adhered with the electroplating accelerator, the immersion time can be reduced, and the production efficiency can be improved. The time that the circuit board immerges in the pre-immersion liquid is 4h-5h, after 4h-5h of soaking, the blind hole of circuit board can be abundant adhere to the pre-immersion liquid, reach the effect of accelerating the interior cladding layer growth rate of blind hole, and the circuit board continues to increase the immersion time after immerging in 4h-5h, because take place marginal benefit and decrement, the increase of immersion time does not have obvious promotion to the effect of accelerating cladding layer growth rate in the blind hole, and can also reduce machining efficiency, be unfavorable for producing good economic benefits.
In one embodiment, the electroplating process of the circuit board comprises a first electroplating process and a second electroplating process, wherein the current density of the first electroplating process is 0.7-0.8 ASD, the electroplating time is 15-20min, the current density of the second electroplating process is 1.4-1.6 ASD, and the electroplating time is 60-90 min. In order to increase the compactness of the plating layer filled by electroplating the blind hole, improve the filling effect and further ensure that the transmission performance of the circuit board is better, in the embodiment, the electroplating process of the circuit board comprises a first electroplating process and a second electroplating process, the current density of the first electroplating process is 0.7ASD-0.8ASD, the electroplating time is 15min-20min, the current density of the second electroplating process is 1.4ASD-1.6ASD, and the electroplating time is 60min-90min, so that the values of the current density of the first electroplating process and the electroplating time are smaller than those of the second electroplating process, the first electroplating process belongs to the beginning stage of the electroplating of the circuit board, the lower current density ensures that the plating layer increasing speed of the interior of the blind hole and the board surface of the circuit board is lower, the copper ions in the electroplating solution have enough time to enter the blind hole, so that the bottom of the blind hole has enough concentration of the copper ions to form a compact plating layer in the beginning stage of the electroplating, the blind hole bottom is the hookup location with another layering of circuit board, the blind hole bottom forms fine and close cladding material, can make the metal material that forms in the blind hole more stable with the circuit connection of another layering, hookup location is difficult for taking place the fracture, the transmission performance of circuit board is also stronger, the current density and the electroplating time numerical value of second electroplating process will be bigger for first electroplating process, the blind hole bottom is the position that electrolyte is difficult to get into most, and in first electroplating process, the bottommost of blind hole has formed fine and close copper coating, for accelerate the speed of electroplating, increase the machining efficiency of circuit board, the current density and the corresponding increase of electroplating time numerical value of second electroplating process, so that the cladding material growth rate of blind hole and face is faster, reach and reduce the electroplating time, accelerate the effect of electroplating efficiency.
In one embodiment, the plating solution includes a copper sulfate solution, a plating accelerator, a plating suppressor, and a plating leveler. The copper sulfate solution is easy to be a common electroplating solution for industrial copper plating, in the embodiment, compared with the traditional electroplating solution for industrial copper plating, the electroplating solution for electroplating the blind holes of the circuit board also comprises an electroplating accelerator, an electroplating inhibitor and an electroplating leveling agent, wherein the electroplating accelerator mainly contains mercaptan micromolecule substances, and in the electroplating process of the circuit board, the electroplating accelerator is mainly enriched in a low current density area, namely the bottom of the blind holes of the circuit board, and the diffusion rate of the electroplating accelerator is high, so that the concentration of the accelerator at the bottom of the blind holes is gradually increased, the accelerator has the function of reducing polarization, the deposition and grain refinement of copper are promoted, and the generation speed of a copper plating layer at the bottom of the blind holes is further accelerated. The electroplating leveling agent is a nitrogen-containing group substance, has extremely strong polarity, is easy to absorb in a high current density area with positive charge, namely a blind hole orifice high potential area of the circuit board, and the diffusion speed of the electroplating leveling agent is slow relative to an electroplating accelerator, so that the concentration of the electroplating leveling agent from the orifice to the orifice bottom is gradually reduced, and the electroplating leveling agent can reduce the orifice plating layer growth speed, so that the orifice plating layer growth speed is lower than that of the orifice bottom, and cavities are prevented from occurring in the holes. The electroplating inhibitor is mainly polyether substance, and the electroplating inhibitor is adsorbed on the board surface of the circuit board under the cooperation of chloride ions, so that the growth speed of the copper plating layer on the board surface is reduced, and the growth speeds of the board surface and the plating layer at the bottom of the blind hole can be relatively average.
As shown in fig. 1 and fig. 2, the present application further provides a circuit board 100, where the circuit board 100 is provided with a blind hole 120 and a through hole 110, and the blind hole 120 of the circuit board 100 is filled by using the blind hole electroplating hole filling method according to any of the embodiments. The blind hole electroplating filling method is used for filling the blind holes 120 on the circuit board 100, and comprises the following steps: immersing the circuit board 100 in a pre-dip solution to adhere the pre-dip solution to the inner wall of the blind via 120, the pre-dip solution including a plating accelerator; immersing the circuit board 100 in a plating solution and guiding the flow of the plating solution around the circuit board 100 in a direction parallel to the axial direction of the through-hole 110 of the circuit board 100; the circuit board 100 is plated so that the blind via 120 is filled with metal.
In this embodiment, through in the immersion fluid that contains the electroplating accelerator with circuit board 100, make be full of the immersion fluid in the blind hole 120 of circuit board 100, and then the electroplating accelerator concentration of hole bottom and pore wall has been improved, the electroplating accelerator has the effect of accelerating cladding material growth rate, consequently, can make the copper coating formation speed of blind hole 120 and face comparatively average, avoid face and drill way cladding material formation speed too fast and lead to the downthehole condition that appears, can reach under the prerequisite that need not to reduce current density and prevent that blind hole 120 from appearing the hollow purpose, it is long when electroplating to need not to prolong, make the machining efficiency of circuit board 100 obtain guaranteeing.
Furthermore, the electroplating solution on the board surface of the circuit board 100 tends to flow towards the through hole 110 and the board edge by guiding the electroplating solution to continuously flow towards the board surface of the circuit board 100, that is, the electroplating solution above the blind hole 120 tends to flow towards the through hole 110 or the board edge, and the electroplating solution inside the blind hole 120 tends to flow outwards due to the difference between the flow rates of the electroplating solutions above the blind hole 120 and inside the blind hole 120, so that the exchange efficiency of the electroplating solution inside the blind hole 120 is improved, thereby causing more copper ions to flow into the blind hole 120, causing enough copper ions to be present inside the blind hole 120 to increase the plating growth rate of the blind hole 120, further ensuring the filling effect of the blind hole 120, and meanwhile, the electroplating solution is guided to continuously flow towards the board surface of the circuit board 100, thereby effectively improving the exchange efficiency of the electroplating solutions inside and outside the blind hole 120, and causing the copper ions of each blind hole, further, the plating layer growth speed of each blind hole 120 is relatively even, the formation of the bulge is effectively prevented on the premise of ensuring full filling, and the quality of the circuit board 100 is improved.
As shown in fig. 3, in one embodiment, the blind hole 120 is opened at a position adjacent to the through hole 110, and an axial direction of the blind hole 120 is parallel to an axial direction of the through hole 110. In order to increase the flow rate difference between the hole opening of the blind hole 120 and the hole bottom, and further increase the liquid exchange efficiency between the hole bottom of the blind hole 120 and the board surface, and achieve the effect of increasing the concentration of copper ions inside the blind hole 120, in this embodiment, the blind hole 120 is opened at a position adjacent to the through hole 110 or at a position at the board edge of the circuit board 100, because the flow rates at the through hole 110 and the board edge are higher, the pressure difference between the position at which the flow rate is higher and other positions of the board surface is larger, and the blind hole 120 is opened at the position adjacent to the flow rate, because the pressure difference between the hole opening of the blind hole 120 and the through hole 110 or the board edge is larger, the flow rate of the plating solution at the hole opening of the blind hole 120 is higher, the flow rate difference between the hole opening of the blind hole 120 and the hole bottom is larger, the tendency of the hole bottom of the blind hole 120 to flow out of the hole is stronger, to increase the speed of copper plating within blind vias 120.
As shown in fig. 3, in one embodiment, the circuit board 100 includes a first base layer 130, a metal conductive layer 150 and a second base layer 140, the first base layer 130, the metal conductive layer 150 and the second base layer 140 are sequentially stacked and connected, a blind via 120 sequentially penetrates through the first base layer 130, the metal conductive layer 150 and the second base layer 140, a through hole 110 sequentially penetrates through the first base layer 130, the metal conductive layer 150 and the second base layer 140, and a portion of the metal conductive layer 150 is exposed in the through hole 110. In the electroplating process of the circuit board 100, due to the different structures of the board surface of the circuit board 100, the blind via 120 and the through via 110, the electrical potentials of the board surface, the blind via 120 and the through via 110 are different, wherein the electrical potential of the board surface is the highest, the electrical potential of the through via 110 is the lowest, the electrical potential is the higher, the electron concentration is the higher, the electron is negatively charged, and the copper ions are attracted, so the copper ions are sequentially attracted by the board surface, the through via 110 and the blind via 120, and the copper ions are attracted by the board surface, the through via 110 and the blind via 120, and the copper plating rate is increased by the copper ions, so that the plating rate generated by the board surface, the through via 110 and the blind via 120 is sequentially decreased, in order to increase the electrical potential at the blind via 120, so that the copper ions have the stronger copper ion attraction capability, and further increase the copper plating rate in the blind via 120, in this embodiment, the, since a portion of the metal conductive layer 150 is exposed in the via hole 110, after the via hole 110 is metalized, the copper plating layer on the through hole 110 is electrically connected to the metal conductive layer 150, and since the blind via 120 penetrates through the metal conductive layer 150, a portion of the metal conductive layer 150 is exposed in the blind via 120, after the blind via 120 is plated with the copper plating layer, the copper plating layer in the blind via 120 is electrically connected to the metal conductive layer 150, thereby realizing the electrical connection between the copper plating layer in the blind via 120 and the copper plating layer in the through via 110, when the blind via 120 is not in conduction with the through via 110, the potential at the through via 110 is higher than the potential at the blind via 120, when the blind via 120 is electrically connected to the through via 110, the potential of the blind via 120 is raised to be the same as the potential of the through via 110, namely, the attraction capacity of the blind hole 120 to copper ions is improved, and the increasing speed of the copper plating layer in the blind hole 120 is correspondingly improved, so that the effects of shortening the electroplating time and improving the filling quality of the filled hole are achieved. It should be noted that the metal conductive layer 150 is not limited to a metal sheet having the same cross section as the first base layer 130 or the second base layer 140, and may also be a metal wire or a metal strip that connects the blind via 120 and the through hole 110.
In one embodiment, in the step of immersing the circuit board in the pre-dipping solution so that the pre-dipping solution adheres to the inner wall of the blind hole, the circuit board is immersed in an electroplating immersion device, as shown in fig. 4 and 5, the electroplating immersion device comprises an electroplating immersion device 10, and the electroplating immersion device 10 comprises an immersion tank 100, a rotating mechanism 200, a clamping mechanism 300 and a vibrating mechanism 400. The soaking tank 100 is provided with a soaking cavity 110; the rotating mechanism 200 comprises a rotating part 210 and a rotating motor 220, the rotating part 210 is arranged in the soaking cavity 110, and the rotating motor 220 is connected with the rotating part 210 so as to enable the rotating part 210 to rotate; the clamping mechanism 300 comprises a plurality of clamping portions 310, and the plurality of clamping portions 310 are connected with the rotating portion 210; the vibration mechanism 400 includes a vibration portion 410 and a vibration motor 420, the vibration portion 410 is disposed in the soaking cavity 110, and the vibration motor 420 is connected to the vibration portion 410, so that the vibration portion 410 vibrates.
In this embodiment, the steeping cistern 100 is for containing a steeping fluid. The rotating mechanism 200 includes a rotating portion 210 and a rotating motor 220, the rotating portion 210 is located in the steeping cistern 100 and is located on the bottom wall of the steeping cistern 100, the rotating motor 220 is used for driving the rotating portion 210 to rotate, so that the rotating portion 210 can rotate in the steeping cistern 100. The clamping mechanism 300 includes a plurality of clamping portions 310, the clamping portions 310 are connected to the rotating portion 210, and the clamping portions 310 are circuit board clips for clamping the circuit board, so that the circuit board can be stably disposed on the rotating portion 210. The vibration mechanism 400 comprises a vibration part 410 and a vibration motor 420, wherein the vibration part 410 is connected with the vibration motor 420, and the vibration motor 420 is used for driving the vibration part 410 to vibrate, so that the vibration part 410 can vibrate the soaking liquid in the soaking tank 100.
Further, the process of soaking the circuit board by using the electroplating soaking device 10 is as follows, a plurality of circuit boards are correspondingly clamped by a plurality of clamping parts 310 of the clamping mechanism 300 respectively, so that the plurality of circuit boards are fixed on the rotating part 210 respectively; pouring a soaking solution into the soaking tank 100 to enable the circuit boards to be soaked in the soaking solution; starting the rotating motor 220, driving the rotating part 210 to rotate in the soaking tank 100 by the rotating motor 220, and driving the circuit board to move together in the soaking tank 100 by the rotating part 210; starting the vibration motor 420, driving the vibration part 410 to vibrate by the vibration motor 420, and vibrating the vibration part 410 in the soaking tank 100 and vibrating the soaking solution in the soaking tank 100; the rotation motor 220 and the vibration motor 420 are continuously started until the soaking time of the circuit board is finished.
Further, because the rotation part 210 drives the circuit board to move in the soaking tank 100, the circuit board and the soaking solution in the soaking tank 100 move relatively, so that the soaking solution can continuously wash the circuit board, the soaking solution can continuously wash the blind holes of the circuit board with the metal cations and the electroplating accelerator in the soaking solution, the blind holes of the circuit board can be continuously washed into the blind holes, the blind holes of the circuit board are sufficiently soaked, the concentration of the metal cations and the electroplating accelerator in the blind holes of the circuit board is increased, and then the subsequent filling effect of electroplating the blind holes is improved.
Further, because the vibration portion 410 vibrates and vibrates the immersion fluid in the immersion tank 100, make the immersion fluid in the immersion tank 100 vibrate ceaselessly, because the vibration that the immersion fluid does not stop, the immersion fluid bubble that is located on the circuit board is extruded in succession, make the immersion fluid also contact with the circuit board that can be more abundant, and then promote the clean effect to the circuit board, and simultaneously, the immersion fluid of ceaseless vibration has bigger internal energy, make the inside and outside immersion fluid of circuit board blind hole flow or exchange more frequently, and then improve the concentration of metal cation and the electroplating accelerating liquid that adheres to in the blind hole, reach better immersion effect.
In one embodiment, as shown in fig. 4 and 5, the inner wall of the soaking chamber 110 is cylindrical. Because the rotating part 210, the clamping part 310 connected with the rotating part 210 and the circuit board can guide the soaking liquid in the soaking tank 100 when the rotating part 210 rotates, so that the soaking liquid rotates in the soaking cavity 110, in order to enable the rotating part 210 to rotate more smoothly in the soaking tank 100, in the embodiment, the inner wall of the cavity of the soaking tank 100 is cylindrical, the soaking liquid rotates in the soaking cavity 110 with the cylindrical inner wall, and the resistance of the soaking cavity 110 to the movement of the soaking liquid is smaller, so that the movement of the soaking liquid is smoother, and the resistance in the rotating rotation is reduced; in addition, when the soaking solution rotates in the soaking cavity 110 with the cylindrical inner wall, the movement is more orderly, so that the distribution of metal cations and electroplating accelerators in the soaking solution is more uniform, and the soaking effect on the blind holes of the circuit board is further improved.
As shown in fig. 4 and 5, in one embodiment, the rotating part 210 includes a rotating disc 211 and a rotating shaft 212, the center of the rotating disc 211 is connected to the rotating shaft 212, the rotating shaft 212 is connected to the rotating motor 220, and the center of the rotating disc 211 coincides with the center of the soaking cavity 110. Rotation motor 220 is used for drive rotation portion 210 to rotate, make rotation portion 210 can be at soaking 100 rotations in the groove, in this embodiment, rotation portion 210 includes carousel 211 and pivot 212, the output shaft and the rotation that rotate motor 220 are connected, and pivot 212 is connected in the central point department of putting of carousel 211, consequently when rotating motor 220 and starting, the output shaft of output motor will drive pivot 212 and carousel 211 in proper order and rotate, a plurality of clamping parts 310 of clamping mechanism 300 all set up on carousel 211, the rotation of carousel 211 can drive clamping part 310 motion, make circuit board and pre-immersion liquid take place relative motion, reach the purpose that improves the effect of soaking.
As shown in fig. 4 and 5, in one embodiment, the clamping mechanism 300 further includes a clamping chassis 320 and a clamping block, the clamping chassis 320 is connected to the clamping block, the rotating portion 210 is provided with a clamping groove, a part of the clamping block is disposed in the clamping groove, so that the clamping chassis 320 is clamped to the rotating portion 210, and a side of the clamping chassis 320 that deviates from the clamping block is connected to the plurality of clamping portions 310. Before the circuit board is soaked, the circuit board needs to be fixed on the clamping part 310 of the soaking tank 100, and because the clamping part 310 is connected with the rotating part 210, that is, the holding portion 310 is located in the soaking tank 100, so that it is very inconvenient to clamp the circuit board, and in order to simplify the work of clamping the circuit board, improve the efficiency of clamping the circuit board, in this embodiment, the clamping mechanism 300 further includes a clamping chassis 320, the plurality of clamping portions 310 are all connected to the clamping chassis 320, the bottom of the clamping chassis 320 is connected to a clamping block, the top surface of the turntable 211 is provided with a clamping groove, the clamping chassis 320 is located on the turntable 211, and the clamping block at the bottom of the clamping chassis 320 is inserted into the clamping groove at the top of the turntable 211, the clamping base plate 320 and the rotary disc 211 can move synchronously, and when the circuit board is soaked, the rotary disc 211 drives the clamping base plate 320, the clamping part 310 and the circuit board to rotate in sequence, so that the effect of relative movement between the circuit board and the pre-soaking liquid is achieved; when the circuit board is clamped, the clamping chassis 320 can be directly taken out from the turntable 211, the circuit board is clamped on the taken-out clamping chassis 320, and then the clamping chassis 320 with the circuit board clamped is installed on the turntable 211, so that the circuit board is clamped. As the circuit board does not need to be clamped in the soaking groove 100, the clamping operation is simpler and more convenient, and the clamping efficiency is correspondingly improved.
As shown in fig. 4 and 5, in one embodiment, a plurality of the clamping portions 310 are arranged in a circumferential array at a central point of the clamping base plate 320. In order to make the soaking effect of the circuit boards on the clamping chassis 320 more even, in the embodiment, the plurality of clamping portions 310 are arranged in a circumferential array around the central point of the clamping chassis 320, namely, the distance between each clamped circuit board and the central point of the clamping chassis 320 is equal, and the distance between two adjacent circuit boards is equal, in the soaking process, because the clamping chassis 320 rotates in the soaking solution, and the position on the clamping chassis 320, which is farther away from the central point of the clamping chassis 320, has a higher relative speed with the soaking solution, and because the distance between each clamped circuit board and the central point of the clamping chassis 320 is equal, therefore, the relative speed of the soaking solution and each circuit board is the same, and the scouring effect of the soaking solution on each circuit board is the same, therefore, the soaking effect of the blind holes in the circuit board can be more balanced, and the filling quality of the blind holes is more consistent.
In one embodiment, as shown in fig. 4 and 5, the fixture 300 further includes a lifting tab 330, and the lifting tab 330 is connected to the fixture chassis 320. Because the clamping chassis 320 is connected to the turntable 211 during soaking, the turntable 211 is located in the soaking groove 100, and the clamping chassis 320 needs to be taken out during circuit board clamping, which is inconvenient, in order to simplify the operation of taking out the clamping chassis 320, in this embodiment, the clamping chassis 320 is connected with the pulling ring 330, when the clamping chassis 320 is taken out and installed, the clamping chassis 320 can be connected with the pulling ring 330 of the clamping chassis 320 through an external pulling mechanism and moved, and then the clamping chassis 320 is taken out from the turntable 211 or installed on the turntable 211, so that the operation of taking out and installing the clamping chassis 320 is simpler and more convenient.
As shown in fig. 4 and 5, in one embodiment, the vibration part 410 includes a vibrating ring 411 and a plurality of vibrating rods 412, the vibrating motor 420 is connected to the vibrating ring 411 to vibrate the vibrating ring 411, the plurality of vibrating rods 412 are connected to the vibrating ring 411, the plurality of vibrating rods 412 are arranged in parallel, and a portion of each vibrating rod 412 is located in the soaking cavity 110. Vibration portion 410 is connected with vibrating motor 420, vibrating motor 420 is used for driving vibration portion 410 to vibrate, make vibration portion 410 can vibrate the immersion fluid that soaks groove 100 not in this embodiment, vibration portion 410 includes vibrating coil 411 and a plurality of vibrating arm 412, a plurality of vibrating arm 412 parallel arrangement each other and all be connected with vibrating coil 411, and vibrating coil 411 is connected with vibrating motor 420, vibrating motor 420 drives vibrating coil 411 vibration, and then drive vibrating arm 412 vibration, a plurality of vibrating arm 412 all stretch into soaks in groove 100, vibrate the immersion fluid, reach the effect of vibration immersion fluid.
As shown in fig. 4 and 5, in one embodiment, the center point of the vibrating ring 411 coincides with the center of the soaking cavity 110, and the vibrating rods 412 are arranged in a circumferential array around the center of the vibrating ring 411. In order to increase the vibration uniformity of the soaking solution in the soaking tank 100, in this embodiment, the center point of the vibrating ring 411 coincides with the center of the soaking cavity 110, and the vibrating rods 412 are arranged in a circumferential array manner with the center of the vibrating ring 411, so that the vibration degrees of all soaking solutions in the soaking tank 100 are more consistent, bubbles in the soaking solution are more thoroughly discharged, and the frequency of the soaking solution exchange inside and outside the blind holes of all circuit boards is more consistent due to the fact that the vibration degrees of all soaking solutions are more consistent, and the purpose of balancing the soaking effect of the blind holes of all circuit boards is achieved.
As shown in fig. 4 and 5, in one embodiment, the immersion tank 100 is provided with a liquid inlet 120 and a liquid outlet 130, and both the liquid inlet 120 and the liquid outlet 130 are communicated with the immersion cavity 110. In order to discharge and input the soak solution in soaking groove 100 fast, in this embodiment, soaking groove 100 has been seted up inlet 120 and liquid outlet 130, inlet 120 and liquid outlet 130 all with soak cavity 110 intercommunication, inlet 120 and liquid outlet 130 all communicate with external pipeline for soak solution in soaking groove 100 can pass through the quick input of inlet 120 and liquid outlet 130 and discharge, and then conveniently change the soak solution in soaking groove 100.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. A blind hole electroplating hole filling method is used for filling blind holes on a circuit board and is characterized by comprising the following steps:
immersing the circuit board in a pre-immersion liquid so that the pre-immersion liquid is attached to the inner wall of the blind hole;
immersing the circuit board into electroplating solution, and guiding the electroplating solution around the circuit board to flow so that the flow direction of the electroplating solution is parallel to the axial direction of the through hole of the circuit board;
and electroplating the circuit board to enable the blind hole to be filled with a metal column, wherein the exposed end part of the metal column is flush with the surface of the circuit board.
2. The blind via plating filling method according to claim 1, wherein the flow rate of the plating solution is 4cm to 6 cm/s.
3. The blind via plating filling method of claim 1, wherein the plating accelerator is present in a concentration of 25% to 30%.
4. A blind via hole electroplating and filling method according to claim 3, wherein the pre-immersion liquid is in a vibration state during immersion of the circuit board in the pre-immersion liquid.
5. The blind via hole electroplating and filling method according to claim 1, wherein the temperature of the pre-immersion liquid is 25-30 ℃, and the time for immersing the circuit board in the pre-immersion liquid is 4-5 h.
6. The blind via hole electroplating and filling method according to claim 1, wherein the electroplating process of the circuit board comprises a first electroplating process and a second electroplating process, the current density of the first electroplating process is 0.7-0.8 ASD, the electroplating time is 15-20min, the current density of the second electroplating process is 1.4-1.6 ASD, and the electroplating time is 60-90 min.
7. The blind via plating via filling method of claim 1, wherein the plating solution comprises a copper sulfate solution, a plating accelerator, a plating inhibitor and a plating leveler.
8. A circuit board, the circuit board is provided with a blind hole and a through hole, and the blind hole of the circuit board is filled by adopting the blind hole electroplating hole filling method of any one of claims 1 to 7.
9. The circuit board according to claim 8, wherein the circuit board is provided with a through hole, the blind hole is provided adjacent to the through hole, and an axial direction of the blind hole is parallel to an axial direction of the through hole.
10. The circuit board of claim 9, wherein the circuit board comprises a first base layer, a metal conductive layer and a second base layer, the first base layer, the metal conductive layer and the second base layer are sequentially stacked and connected, the blind via sequentially penetrates through the first base layer, the metal conductive layer and the second base layer, the through via sequentially penetrates through the first base layer, the metal conductive layer and the second base layer, and a portion of the metal conductive layer is exposed in the through via.
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| CN114507886A (en) * | 2022-03-29 | 2022-05-17 | 四会富仕电子科技股份有限公司 | Hole-filling electroplating method |
| WO2022099982A1 (en) * | 2020-11-16 | 2022-05-19 | 淮安特创科技有限公司 | Circuit board soaking apparatus and circuit board processing equipment |
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| WO2022099982A1 (en) * | 2020-11-16 | 2022-05-19 | 淮安特创科技有限公司 | Circuit board soaking apparatus and circuit board processing equipment |
| CN113630963A (en) * | 2021-07-08 | 2021-11-09 | 广州美维电子有限公司 | Method for improving deformation of ultrathin plate |
| CN114507886A (en) * | 2022-03-29 | 2022-05-17 | 四会富仕电子科技股份有限公司 | Hole-filling electroplating method |
| CN115297618A (en) * | 2022-10-08 | 2022-11-04 | 广州添利电子科技有限公司 | Radar plate PCB manufacturing process |
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