TWI677269B - Method for electroplating circuit board structure in hole - Google Patents

Abstract

The invention discloses a method for electroplating in a hole of a circuit board structure, which comprises: implementing a preparation step: providing a circuit board, and the circuit board includes a hole; wherein the hole has a depth and a width of the hole divided by a depth. And the aspect ratio is not less than 4; implementing a first plating step: plating the holes of the circuit board with a first current for a first period of time, and the first current has a A first current density value; and implementing a second electroplating step: electroplating the holes of the circuit board with a second current in a second period, and the second current has a second current density value Wherein, the first current density value and the second current density value are different from each other, and each is between 4 ASF and 60 ASF.

Description

In-hole plating method for circuit board structure

The invention relates to a circuit board, in particular to a method for plating in a hole of a circuit board structure.

Existing circuit board manufacturing methods use constant current density (that is, the current density is maintained at a constant value) when performing hole plating on circuit boards. In order to achieve the effect of uniform plating, the existing circuit board manufacturing methods need to use A small current density increases the rate of hole filling, but the above-mentioned smaller current density will increase the plating time and thus reduce the plating efficiency.

Furthermore, when the existing circuit board manufacturing method is used to plate holes having an aspect ratio of less than 4, its influence on the plating time and the plating efficiency is less obvious, but with the development of the circuit board year by year, the circuit board needs to be formed. The ratio of holes with high aspect ratio is also getting higher and higher, so the current circuit board manufacturing method for the plating method of holes with high aspect ratio also needs to be further improved.

Therefore, the present inventor believes that the above-mentioned defects can be improved, and with special research and cooperation with the application of scientific principles, he finally proposes an invention with a reasonable design and effective improvement of the above-mentioned defects.

An embodiment of the present invention is to provide an in-hole plating method for a circuit board structure, which It can effectively improve the defects that may occur in the existing circuit board manufacturing methods.

An embodiment of the present invention discloses a method for plating in a hole of a circuit board structure, which includes: implementing a preparation step: providing a circuit board, and the circuit board includes a hole; wherein the hole has a hole depth divided by a hole diameter. Aspect ratio, and the aspect ratio is not less than 4; implementing a first electroplating step: electroplating the holes of the circuit board in a first period with a first current, and the first current Has a first current density value; and implements a second plating step: plating the holes of the circuit board with a second current in a second period of time, and the second current has a second current Density value; wherein the first current density value and the second current density value are different from each other, and each is between 4 ASF and 60 ASF.

An embodiment of the present invention also discloses a method for plating in a hole of a circuit board structure, which includes: implementing a preparation step: providing a circuit board, and the circuit board includes a hole; wherein the hole has a hole depth divided by An aspect ratio, and the aspect ratio is not less than 4; and sequentially performing N electroplating steps: each of the electroplating steps electroplating the holes of the circuit board with a current, and the current has A current density value; wherein N is a positive integer not less than 2, and the N number of the electroplating steps includes more than two types of the current density value, and any one of the current density values is between 4 ASF ~ 60ASF; wherein, when the difference between the two current density values used in any two of the electroplating steps sequentially performed is greater than 2 ASF, a current conversion step is performed; wherein, the current conversion step The holes of the circuit board are plated with a step current in a conversion period, and the step current has a step current density value, and the step current density value is in the conversion period The current density of the first two from the current density values used in the embodiment to embodiment gradually changes the value of the current density; wherein said transition period between 0 to 20 minutes.

In summary, in the method for in-hole electroplating of the circuit board structure disclosed in the embodiments of the present invention, multiple electroplating steps (such as the first electroplating step and the second electroplating step) can be used by using between 4 ASF ~ 60ASF And different current density values, so that Under the premise of considering the hole filling rate as much as possible, the plating efficiency and the plating effect can be effectively improved (for example, a better hole filling rate can be achieved).

In order to further understand the features and technical contents of the present invention, please refer to the following detailed description and drawings of the present invention, but these descriptions and drawings are only used to illustrate the present invention, and not to make any limitation to the scope of the present invention limit.

1‧‧‧Circuit Board

11‧‧‧ Hole

2‧‧‧ Conductor

21‧‧‧ space

3‧‧‧ Conductor

X‧‧‧first current

Y‧‧‧second current

Z‧‧‧ Ladder current

T1‧‧‧First Session

T2‧‧‧Second Session

Tc‧‧‧ Conversion Period

I‧‧‧First current density value

Ⅱ‧‧‧Second current density value

R‧‧‧ Aperture

D‧‧‧hole depth

FIG. 1 is a schematic diagram of preparation steps in Embodiment 1 of a method for plating in a hole of a circuit board structure according to the present invention.

FIG. 2 is a schematic diagram of current densities and times of a first plating step and a second plating step in Embodiment 1 of a method for plating a hole in a circuit board structure according to the present invention.

FIG. 3 is a schematic diagram of a circuit board structure after an embodiment of a method for plating in a hole of a circuit board structure according to the present invention is implemented.

FIG. 4 is a schematic diagram of the current density and time of the first plating step and the second plating step in the second embodiment of the in-hole plating method of the circuit board structure of the present invention.

FIG. 5 is a schematic diagram of a circuit board structure after the second embodiment of the in-hole plating method of the circuit board structure of the present invention is implemented.

FIG. 6 is a schematic diagram (1) of the current density and time of the first plating step and the second plating step in the third embodiment of the in-hole plating method of the circuit board structure of the present invention.

FIG. 7 is a schematic diagram (2) of current densities and times of the first plating step and the second plating step in the third embodiment of the in-hole plating method of the circuit board structure of the present invention.

Please refer to FIG. 1 to FIG. 7, which are embodiments of the present invention. It should be noted that this embodiment corresponds to the related quantities and appearances mentioned in the drawings, and is only used to specifically describe the implementation of the present invention. Mode to facilitate understanding of the content of the present invention, but not to limit the protection scope of the present invention.

[Example 1]

It should be noted that, to facilitate the description of this embodiment, the drawings only show relevant local structures. As shown in FIG. 1 to FIG. 3, this embodiment discloses a method for in-hole plating of a circuit board structure, which includes a preparation step, a first plating step, and a second plating step. Wherein, any electroplating step in the in-hole electroplating method of the circuit board structure of this embodiment may be implemented by an electroplating device (not shown), that is, various parameters in the electroplating step may be controlled by the electroplating device.

Furthermore, the in-hole plating method of the circuit board structure of the present invention is not limited to the sequence or implementation of the above steps. For example, in other embodiments not shown in the present invention, the above multiple steps may also be adjusted, changed, increased or decreased according to actual design requirements. In addition, each step of the in-hole plating method of the circuit board structure of this embodiment will be described below.

As shown in FIG. 1, the preparation step is implemented: a circuit board 1 is provided, and the circuit board 1 includes a hole 11. The circuit board 1 in this embodiment may be a multi-layer board or a single-layer board, and the hole 11 is illustrated in FIG. 1 as a through hole penetrating the circuit board 1, but the present invention is not limited thereto. For example, in other embodiments not shown in the present invention, the hole 11 may not pass through a blind hole of the circuit board 1.

Furthermore, in the embodiment, the hole 11 has an aspect ratio (AR) divided by a hole depth D divided by an aperture R, and the aspect ratio is not less than 4. That is, the object or object to which the in-hole plating method of the circuit board structure of this embodiment is applicable is to exclude holes having an aspect ratio of less than 4.

As shown in FIG. 2, the first electroplating step is performed: the holes 11 of the circuit board 1 are electroplated in a first period T1 with a first current X, and the first current X has a first Current density value I. In this embodiment, the first period T1 is between 5 minutes and 80 minutes, and the first current density value of the first current X is I is between 4 ASF and 60 ASF. The ASF is used as a current density unit in this embodiment, that is, ampere / square foot.

As shown in FIG. 2, the second plating step is performed: the holes 11 of the circuit board 1 are plated with a second current Y within a second period T2, and the second current Y has a second Current density value II. In this embodiment, the second period T2 is between 5 minutes and 80 minutes, and the second current density value II of the second current Y is between 4 ASF and 60 ASF.

It should be noted that, as shown in FIG. 2 and FIG. 3, the first current density value I and the second current density value II are different from each other, and the first current density value I and the second current density value II are different from each other. The difference is better than 2 ASF in this embodiment, so that the first current density value I can be instantly converted to the second current density value II.

Furthermore, after the above-mentioned steps are performed in the in-hole plating method of the circuit board structure, a conductive body 2 plated on the hole wall of the hole 11 is formed, and an inner edge of the conductive body 2 forms a space 21. .

Further, in order to effectively form the conductive body 2 in the hole 11, the first current density value I is preferably smaller than the second current density value II. The first current density value I is, for example, between 4 ASF and 12 ASF, and the second current density value II is, for example, between 10 ASF and 30 ASF.

[Example 2]

Please refer to FIG. 4 and FIG. 5, which is a second embodiment of the present invention. This embodiment is similar to the first embodiment, so the same points (such as the preparation steps) of the two embodiments will not be described again. The difference between this embodiment and the first embodiment is mainly that: after the in-hole electroplating method of the circuit board structure of this embodiment is implemented, a conductive body 3 plated on the hole 11 is formed.

Specifically, in order to effectively form the conductive body 3 in the hole 11, The first current density value I is preferably greater than the second current density value II. The first current density value I is, for example, between 10 ASF and 60 ASF, and the second current density value II is, for example, between 4 ASF and 15 ASF.

[Example Three]

Please refer to FIG. 6 and FIG. 7, which is a third embodiment of the present invention. This embodiment is similar to the first embodiment and the second embodiment. Therefore, the same aspects of the above embodiments (such as the preparation step, the first plating step, and The second electroplating step) will not be repeated, and the difference between this embodiment and the first and second embodiments is mainly that the in-hole electroplating method of the circuit board structure of this embodiment is performed in the first electroplating step and the second electroplating step. A current conversion step is further implemented therebetween.

Specifically, the current conversion step is implemented as follows: the holes 11 of the circuit board 1 are plated with a step current Z within a conversion period Tc, and the step current Z has a step current density value. The step current density value is gradually changed (eg, increased or decreased) from the first current density value I to the second current density value II within the transition period Tc.

The conversion period Tc in this embodiment is between 0 and 20 minutes, and the length of the conversion period Tc is roughly based on the difference between the first current density value I and the second current density value II. Decide. Further, after actual operation of the method for plating in holes in the circuit board structure of this embodiment, the following correspondence table of the relationship between the current density difference and the conversion period Tc is obtained.

According to the above table, when the difference between the first current density value I and the second current density value II is less than 2 ASF, the conversion period Tc is 0 minutes, which is equivalent to the first embodiment and the second embodiment. The first current density value I described in the above is instantly converted to the second current density value II.

Furthermore, when the difference between the first current density value I and the second current density value II is between 3 and 5 ASF, the conversion period Tc is 1 to 11 minutes; the first current density value I and the second When the difference between the current density values II is 6 to 9 ASF, the conversion period Tc is 12 to 19 minutes; when the difference between the first current density value I and the second current density value II is more than 10 ASF, the The switching period Tc is 20 minutes.

According to this, the in-hole plating method of the circuit board structure of this embodiment can adjust the time length of the conversion period Tc according to the difference between the first current density value I and the second current density value II, thereby enabling the circuit board described above. The hole 11 of 1 has better plating effect and plating efficiency.

It should be additionally noted that the first to third embodiments are described by using two electroplating steps (eg, the first electroplating step and the second electroplating step), but the number of electroplating steps performed by the in-hole electroplating method of the circuit board structure of the present invention It is not limited to this.

Further, in an embodiment not shown in the present invention, the in-hole electroplating method of the circuit board structure may be implemented by sequentially performing N electroplating steps, and N is a positive integer of not less than 2; Each electroplating step electroplats the holes 11 of the circuit board 1 with a current, and the current has a current density value. Furthermore, the above N plating steps include two or more current density values, and any one of the current density values is between 4 ASF and 60 ASF.

In more detail, when the difference between the two current density values used in any two of the electroplating steps sequentially performed is greater than 2 ASF, a current conversion step is performed; and when any of the two When the difference between the two current density values used in the electroplating step sequentially performed is less than 2 ASF, the two current density values can be instantly converted.

Wherein, the current conversion step is to plate the holes 11 of the circuit board 1 with a step current within a conversion period, and the step current has a step current density value, and the step current density value is During the conversion period, from the implementation of the current density value in the two of the current density values used, the current density value is gradually changed to the implementation of the current density value in the following. Moreover, the conversion period is between 0 and 20 minutes, and the specific time length can be referred to that in the third embodiment.

It should be additionally noted that the current density values used in the above-mentioned N electroplating steps can be controlled according to actual needs: from high to low, from low to high, or from high to low, which is not limited in the present invention.

In addition, for the existing circuit board manufacturing method, under the premise of taking into account the hole filling ratio as much as possible, the plating efficiency for holes with an aspect ratio greater than 4 and less than 8 will be reduced by 10%, and for aspect ratios greater than 8 and The plating efficiency of holes less than 11 will be reduced by 40%, and the plating efficiency of holes with aspect ratios greater than 11 and less than 16 will be reduced by 70%. Among them, the existing circuit board manufacturing method has a difficulty in achieving a hole filling ratio of 60% for holes having an aspect ratio greater than 11 and less than 16.

However, after actual operation, the in-hole electroplating method of the circuit board structure of this embodiment has a plating efficiency of holes 11 with an aspect ratio greater than 4 and less than 16 compared with the existing circuit on the premise of taking into account the filling rate as much as possible. The board manufacturing method can be effectively improved. Furthermore, the in-hole electroplating method of the circuit board structure disclosed in the embodiment of the present invention can achieve a filling rate of the hole 11 with an aspect ratio greater than 11 and less than 16 to reach 60% or more.

[Technical effect of the embodiment of the present invention]

In summary, in the method for in-hole electroplating of the circuit board structure disclosed in the embodiments of the present invention, multiple electroplating steps (such as the first electroplating step and the second electroplating step) can be used by using between 4 ASF ~ 60ASF And the current density values are different from each other, so that the plating efficiency and the plating effect can be effectively improved under the premise of considering the hole filling rate as much as possible. (Such as: to achieve a better filling rate).

Furthermore, the in-hole plating method of the circuit board structure of this embodiment can further be based on the difference between the current density values (such as the difference between the first current density value and the second current density value) of the two plating steps. By adjusting the length of the conversion period, the holes of the circuit board can have better plating effect and plating efficiency.

The above description is only the preferred and feasible embodiments of the present invention, and is not intended to limit the protection scope of the present invention. Any equivalent changes and modifications made according to the patent scope of the present invention shall fall within the protection scope of the claims of the present invention.

Claims (10)

A method for in-hole plating of a circuit board structure includes: implementing a preparation step: providing a circuit board, and the circuit board includes a hole; wherein the hole has a depth-to-width ratio of its hole depth divided by the hole diameter, and The aspect ratio is not less than 4; a first plating step is performed: the holes of the circuit board are plated with a first current for a first period of time, and the first current has a first current A density value; and implementing a second electroplating step: electroplating the holes of the circuit board with a second current in a second period, and the second current has a second current density value; wherein, The first current density value and the second current density value are different from each other, and each is between 4 ASF and 60 ASF. The method for in-hole plating of a circuit board structure according to claim 1, is implemented to form a conductive body plated on a wall of the hole of the hole, so that a space is formed around the inner side of the conductive body, and The first current density value is smaller than the second current density value. The in-hole plating method for a circuit board structure according to claim 2, wherein the first current density value is between 4 ASF and 12 ASF, and the second current density value is between 10 ASF and 30 ASF. The method for in-hole plating of a circuit board structure according to claim 1 is implemented to form a conductor plated on the hole, and the first current density value is greater than the second current density value. The in-hole plating method for a circuit board structure according to claim 4, wherein the first current density value is between 10 ASF and 60 ASF, and the second current density value is between 4 ASF and 15 ASF. The method for in-hole plating of a circuit board structure according to claim 1, further comprising: implementing a current conversion step: applying a step current to the circuit between the first plating step and the second plating step. The holes of the plate are electroplated in a conversion period, and the step current has a step current density value, and the step current density value gradually changes from the first current density value to The second current density value; wherein the transition period is between 0 and 20 minutes. The method for in-hole plating of a circuit board structure according to claim 6, wherein when the difference between the first current density value and the second current density value is less than 2ASF, the conversion period is 0 minutes; When the difference between the first current density value and the second current density value is more than 10 ASF, the conversion period is 20 minutes. The method for in-hole plating of a circuit board structure according to claim 6, wherein when the difference between the first current density value and the second current density value is between 3 and 5 ASF, the conversion period is 1 to 11 minutes. The in-hole plating method for a circuit board structure according to claim 6, wherein when the difference between the first current density value and the second current density value is between 6 and 9 ASF, the conversion period is 12 to 19 minutes. A method for in-hole plating of a circuit board structure includes: implementing a preparation step: providing a circuit board, and the circuit board includes a hole; wherein the hole has a depth-to-width ratio of its hole depth divided by the hole diameter, and The aspect ratio is not less than 4; and sequentially performing N electroplating steps: each of the electroplating steps electroplating the holes of the circuit board with a current, and the current has a current density value; wherein , N is a positive integer not less than 2, and N or more of the current density values are included in the N electroplating steps, and any one of the current density values is between 4 ASF and 60 ASF; When the difference between the two current density values used in the two sequentially performed electroplating steps is greater than 2ASF, a current conversion step is performed; wherein, the current conversion step is a step current The holes of the circuit board are electroplated in a conversion period, and the step current has a step current density value, and the step current density value during the conversion period is Said current density in the first embodiment of the current density is gradually changed to the embodiment of the current density value; wherein the transition period between 0 to 20 minutes.