PLATING SYSTEM AND METHOD THEREOF

Abstract

A plating system and a method thereof are disclosed. The plating system performs a N-stage plating drilling filling process in which a M-th stage plating drilling filling process with a M-th current density is performed on a hole of a substrate for a M-th plating time to form a M-th plating layer on the to-be-plated layer, wherein N is a positive integer equal to or greater than 3, and M is a positive integer positive integer in a range of 1 to N. Therefore, the technical effect of providing a higher drilling filling rate than conventional plating filling technology under a condition that a total thickness of plating layers is fixed can be achieved.

Claims

1. A plating system, comprising: a substrate, comprising at least one hole formed therein and a to-be-plated layer formed on a surface thereof; a power supply device, comprising a cathode and an anode, wherein the substrate is disposed on the cathode, and the power supply device is configured to supply power and adjust a current density for plating; an plating tank, configured to accommodate plating solution with metal ion, wherein the substrate and the anode are immersed in the plating solution in the plating tank; wherein the power supply device is activated and set to perform a N-stage plating drilling filling process in which a M-th stage plating drilling filling process with a M-th current density for a M-th plating time to form a M-th plating layer on the to-be-plated layer in the at least one hole, N is a positive integer equal to or greater than 3, and M is a positive integer in a range of 1 to N, and the power supply device is then stopped supplying power, and the substrate is taken out of the plating solution to perform a cleaning and drying process.

2. The plating system according to claim 1, wherein when N is equal to 3, a second current density used for a second-stage plating drilling filling process is in a rage of 90% to 110% a first current density used for a first-stage plating drilling filling process, and a third current density used for a third-stage plating drilling filling process is in a range of 20% to 30% the second current density used for the second-stage plating drilling filling process.

3. The plating system according to claim 1, wherein the current density used for each of stages of the N-stage plating drilling filling process is in a range of 0.5 ASD to 100 ASD, and the current densities used for the N-stage plating drilling filling process are the same or different.

4. The plating system according to claim 1, wherein the thicknesses of the plating layers are the same or different.

5. The plating system according to claim 1, wherein the metal ion is metal ion other than copper ion.

6. A plating method, comprising: providing a substrate comprising at least one hole formed therein and a to-be-plated layer formed on a surface thereof; providing a power supply device comprising a cathode and an anode, wherein the substrate is disposed on the cathode, the power supply device is configured to supply power for plating and adjust a current density for plating; providing a plating tank configured to accommodate plating solution with metal ion, wherein the substrate and the anode are immersed in the plating solution in the plating tank; activating and setting the power supply device to perform a M-th stage plating drilling filling process with a M-th current density for a M-th plating time, to form a M-th plating layer on the to-be-plated layer in the at least one hole, wherein N is a positive integer equal to or greater than 3, and M is a positive integer in a range of 1 to N; and stopping the power supply device from supplying power, and taking the substrate out of the plating solution to perform a cleaning and drying process.

7. The plating method according to claim 6, wherein when N is equal to 3, a second current density used for a second-stage plating drilling filling process is in a rage of 90% to 110% a first current density used for a first-stage plating drilling filling process, and a third current density used for a third-stage plating drilling filling process is in a range of 20% to 30% the second current density used for the second-stage plating drilling filling process.

8. The plating method according to claim 6, wherein the current density used for each of stages of the N-stage plating drilling filling process is in a range of 0.5 ASD to 100 ASD, and the current densities used for the N-stage plating drilling filling process are the same or different.

9. The plating method according to claim 6, wherein the thicknesses of the plating layers are the same or different.

10. The plating method according to claim 6, wherein the metal ion is metal ion other than copper ion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The structure, operating principle and effects of the present invention will be described in detail by way of various embodiments which are illustrated in the accompanying drawings.

[0014] FIG. 1 is a schematic view of an architecture of a plating system, according to the present invention.

[0015] FIG. 2 is a sectional view of a substrate of the present invention.

[0016] FIG. 3 is a schematic view of plating layers formed in multiple stages, according to the present invention.

[0017] FIG. 4 is a schematic view of definition of drilling filling rate, according to the present invention.

[0018] FIGS. 5A to 5E are a diagram showing a simulation result of a single-stage plating filling process with different current densities.

[0019] FIG. 6A is a diagram showing a simulation result of a single-stage plating filling process with single current density.

[0020] FIG. 6B is a diagram showing a simulation result of a drilling filling process with different current densities, wherein a thickness of a plating layer in each stage is the same.

[0021] FIG. 7A is a diagram showing a simulation result of single-stage plating filling process with single current density.

[0022] FIG. 7B is a diagram showing a simulation result of drilling filling process with different current densities, wherein a thickness of the plating layer in each stage is the same.

[0023] FIG. 8 is a flowchart of a plating method, according to the present invention.

DETAILED DESCRIPTION

[0024] The following embodiments of the present invention are herein described in detail with reference to the accompanying drawings. These drawings show specific examples of the embodiments of the present invention. These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. It is to be acknowledged that these embodiments are exemplary implementations and are not to be construed as limiting the scope of the present invention in any way. Further modifications to the disclosed embodiments, as well as other embodiments, are also included within the scope of the appended claims.

[0025] These embodiments are provided so that this disclosure is thorough and complete, and fully conveys the inventive concept to those skilled in the art. Regarding the drawings, the relative proportions and ratios of elements in the drawings may be exaggerated or diminished in size for the sake of clarity and convenience. Such arbitrary proportions are only illustrative and not limiting in any way. The same reference numbers are used in the drawings and description to refer to the same or like parts. As used herein, the singular forms a, an and the are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0026] It is to be acknowledged that, although the terms first, second, third, and so on, may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only for the purpose of distinguishing one component from another component. Thus, a first element discussed herein could be termed a second element without altering the description of the present disclosure. As used herein, the term or includes any and all combinations of one or more of the associated listed items.

[0027] It will be acknowledged that when an element or layer is referred to as being on, connected to or coupled to another element or layer, it can be directly on, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being directly on, directly connected to or directly coupled to another element or layer, there are no intervening elements or layers present.

[0028] In addition, unless explicitly described to the contrary, the words comprise and include, and variations such as comprises, comprising, includes, or including, will be acknowledged to imply the inclusion of stated elements but not the exclusion of any other elements.

[0029] The operation of a plating system of the present invention will be described in the following paragraphs. Please refer to FIGS. 1 and 2. FIG. 1 is a schematic view of an architecture of a plating system according to the present invention, and FIG. 2 is a sectional view of a substrate of the present invention.

[0030] As shown in FIG. 1, the present invention provides a plating system, and plating system includes a substrate 10, a power supply device 20 and a plating tank 30.

[0031] A thickness D of the substrate 10 can be, but not limited to, in a range of 0.2 mm to 3 mm, the substrate 10 can be a BT substrate, a FR4 substrate, a copper substrate or an ABF substrate. The material of the substrate 10 can be, but not limited to, fiberglass, epoxy resin, polyphenylene oxide (PPO), polyimide (PI), polypropylene (PP), or a combination thereof. It should be noted that the substrate 10 can be, but not limited to, a printed circuit board (PCB). A laser or mechanical drilling process can be performed on the substrate 10 to form at least one hole 11. FIG. 1 shows single hole for schematic illustration, but the application field of the present invention is not limited to, these examples; the quantity and positions of the holes 11 can be adjusted according to practical demand. When the hole 11 is a round hole (that is, the top view of the hole 11 is a circle), a hole diameter of the hole 11 can be in a range of 50 ?m to 200 ?m, and an AR value, which is a ratio of a thickness of the substrate 10 to the hole diameter, can be in a range of 0.5 to 4.0; however, these examples are merely for exemplary illustration, and the application field of the present invention is not limited to, these examples.

[0032] The substrate 10 can have a to-be-plated layer 12 formed on double sides thereof, but the present invention is not limited to, this embodiment; this embodiment can be adjusted according to practical demand. For example, the substrate 10 can have the to-be-plated layer 12 only formed on a surface having the at least one hole 11. The substrate 10 is non-conductor, so one of an electroless plating drilling filling process, a physical vapor deposition process and a chemical vapor deposition process is required to perform on the surface of the substrate 10, to make the substrate 10 have a conductive layer, which is the to-be-plated layer 12, on the surface thereof. The material of the to-be-plated layer 12 can be selected from the group consisting of silver, gold, nickel, cobalt, palladium and copper; in an embodiment, the material can be adjusted according to practical demand.

[0033] The substrate 10 is cleaned by a pre-treatment process, the pre-treatment process includes following operations. First, the to-be-plated layer 12 formed on the substrate 10 and the hole 11 is cleaned by water, cleaning agent and pickle liquor in sequential order; in more detail, the pre-treatment process is performed to remove stain on the to-be-plated layer 12 and an oxide layer on the surface of the to-be-plated layer 12. In order to prevent from remaining bubble on the to-be-plated layer 12 during cleaning process, the above-mentioned water can be, but not limited to, DI water. It should be noted that when the pickle liquor for cleaning does not have the ion of the plating solution, the to-be-plated layer 12 can be cleaned by water again to prevent the quality of plating metal in later plating drilling filling process from being affected.

[0034] The power supply device 20 includes a cathode 21 and an anode 22, the substrate 10 having the to-be-plated layer 12 is disposed at the position of the cathode 21. In an embodiment, a soluble anode, which is for replenishing the metal ions consumed in the plating solution, can be disposed at the position of the anode 22; or an insoluble anode (such as titanium mesh, iridium/tantalum, or oxide composite anode) can be disposed at the position of the anode 22. However, these examples are merely for exemplary illustration, and the application field of the present invention is not limited to, these examples. In this embodiment, the material of the anode 22 can be, but not limited to, iridium/tantalum oxide composite insoluble anode.

[0035] The power supply device 20 is configured to supply power and adjust the current density for the plating drilling filling process performed on the substrate 10, the plating solution 31 with metal ions is accommodated in the plating tank 30, the substrate 10 and the anode 22 of the power supply device 20 are immersed in the plating solution 31 in the plating tank 30. When the power supply device 20 supplies power, the plating drilling filling process is performed on the substrate 10. In an embodiment, the metal ion can be any metal ion other than copper ion, for example, the metal ion can be silver ion, gold ion, nickel ion, cobalt ion, or palladium ion, but these examples are merely for exemplary illustration, and the application field of the present invention is not limited to these examples; the metal ion can be adjusted according to the material of the M-th plating layer expected to form.

[0036] Please refer to FIG. 3, which is a schematic view of plating layers formed in multiple stages, according to the present invention. FIG. 3 shows three plating layers (that is, the three-stage plating drilling filling process) as an example for illustration, but the application field of the present invention is not limited to the above-mentioned examples.

[0037] When the power supply device 20 is activated and set to perform a N-stage plating drilling filling process in which a M-th stage plating drilling filling process with a M-th current density for a M-th plating time to form a M-th plating layer on the to-be-plated layer in the at least one hole, N is a positive integer equal to or greater than 3, and M is a positive integer in a range of 1 to N. An embodiment with N being 3 and M in a range of 1 to 3 is illustrated in the following paragraphs, but the embodiment is merely for exemplary illustration, and the application field of the present invention is not limited to the embodiment.

[0038] The power supply device 20 adjusts the current density to the first current density and performs the first-stage plating drilling filling process on the to-be-plated layer 12 of the substrate 10 for a first plating time, so as to form the first plating layer 131 on the to-be-plated layer 12 in the hole 11.

[0039] The power supply device 20 adjusts the current density to the second current density and performs the second-stage plating drilling filling process on the first plating layer 131 for a second plating time, so as to form the second plating layer 132 on the first plating layer 131 in the hole 11.

[0040] Next, the power supply device 20 adjusts the current density to the third current density and performs the third-stage plating drilling filling process on the second plating layer 132 for a third plating time, so as to form the third plating layer 133 on the second plating layer 132 in the hole 11.

[0041] In the present invention, the M-th current density and the expected thickness THK of the M-th plating layer are set; next, the M-th plating time required for the plating drilling filling process are calculated through the Faraday's Law based on the M-th current density. the Faraday's Law equation is as follows:

[00001]$t=\frac{THK}{0.22?j}$

[0042] t is the M-th plating time in a unit of minute, THK is the thickness THK of the M-th plating layer in a unit of and j is the M-th current density in a unit of A/dm.sup.2 (ASD).

[0043] It should be noted that the current density used in the each stage plating drilling filling process (that is, the first current density, the second current density, the third current density) is in a range of 0.5 ASD to 100 ASD, and the current density used in the each stage plating drilling filling process can be the same or different.

[0044] In an embodiment with n being 3 and m being 1, the second current density used in the second stage plating drilling filling process is in a range of 90% to 110% the first current density used in the first stage plating drilling filling process, the third current density used in the third stage plating drilling filling process is in a range of 20% to 30% the second current density used in the second stage plating drilling filling process. Particularly, in a condition that the first current density used in the first stage plating drilling filling process is set as 1 ASD, the second current density used in the second stage plating drilling filling process is in a range of 1.9 to 2.1; in a condition that the second current density used in the second stage plating drilling filling process is set as 2 ASD, the third current density used in the third stage plating drilling filling process is in a range of 0.4 to 0.6. However, these examples are merely for exemplary illustration, and the application field of the present invention is not limited to the above-mentioned examples.

[0045] The simulation of plating drilling filling process using COMSOL-Multiphysics (version 6.0) is described in the following paragraphs. Please refer to FIGS. 4 and 5A to 5E. FIG. 4 is a schematic view of the definition for the drilling filling rate of the present invention, and FIGS. 5A to 5E are a diagram showing a simulation result of a single-stage plating filling process with different current densities.

[0046] The drilling filling rate of the present invention is defined by dividing a distance b that is from the lowest position on the surface of the plating layer to the bottom of the hole by a distance a that is from the highest position on the surface of the plating layer to the bottom of the hole, and multiplying the division result by 100%; that is, the drilling filling rate=b/a?100%, as shown in FIG. 4. It should be noted that the actual thickness of the to-be-plated layer 12 is not high, so the actual thickness of the to-be-plated layer 12 can be ignored in the process of calculating the distance a and the distance b, and the distance a and the distance b can also include the thickness of the to-be-plated layer 12.

[0047] As shown in FIG. 5A, a single-stage plating drilling filling process with a single current density of 0.5 ASD is performed to form a plating layer with a fixed thickness of 15 ?m. For the plating drilling filling process with the current density of 0.5 ASD, a simulation result of the plating time is 136.36 minutes and a simulation result of the drilling filling rate is 66.8%, which is calculated based on

[00002]$\frac{b}{a}?100\%.$

[0048] As shown in FIG. 5B, a single-stage plating drilling filling process with a single current density of 1 ASD is performed to form a plating layer with a fixed thickness of 15 ?m. For the plating drilling filling process with the current density of 1 ASD, a simulation result of the plating time is 68.18 minutes and a simulation result of drilling filling rate is 66.7%, which is calculated based on

[00003]$\frac{b}{a}?100\%.$

[0049] As shown in FIG. 5C, a single-stage plating drilling filling process with a single current density of 2 ASD is performed to form a plating layer with a fixed thickness of 15 ?m. For the plating drilling filling process with the current density of 2 ASD, a simulation result of the plating time is 34.09 minutes and a simulation result of drilling filling rate is 66.5%, which is calculated based on

[00004]$\frac{b}{a}?100\%.$

[0050] As shown in FIG. 5D, the single-stage plating drilling filling process with a single current density of 5 ASD is performed to form a plating layer with a fixed thickness of 15 ?m. For the plating drilling filling process with the current density of 5 ASD, a simulation result of plating time is 13.63 minutes and a simulation result of drilling filling rate is 66%, which is calculated based on

[00005]$\frac{b}{a}?100\%.$

[0051] As shown in FIG. 5E, the single-stage plating drilling filling process with a single current density of 10 ASD is performed to form a plating layer with a fixed thickness of 15 ?m. For the plating drilling filling process with the current density of 10 ASD, a simulation result of plating time is 6.81 minutes and a simulation result of drilling filling rate is 64.5%, which is calculated based on

[00006]$\frac{b}{a}?100\%.$

[0052] According to the above-mentioned simulation results, in order to form a plating layer with the fixed thickness of 15 ?m, the plating drilling filling process with a higher current density (such as 10 ASD) requires much less plating time than the plating drilling filling process with a lower current density (such as 1 ASD), but the plating drilling filling process with a higher current density (such as 10 ASD) has a much lower drilling filling rate than the plating drilling filling process with a lower current density (such as 1 ASD), so using a higher current density (such as 5 ASD or 10 ASD) is unfavorable for improving the drilling filling rate.

[0053] Please refer to FIGS. 6A and 6B. FIG. 6A is a diagram showing a simulation result of a single-stage plating drilling filling process with single current density, and FIG. 6B is a diagram showing a simulation result of a plating drilling filling process with different current densities, wherein a thickness of the plating layer in each stage is the same.

[0054] As shown in FIG. 6A, for the single-stage plating drilling filling process with a single current density of 2 ASD to form a plating layer with a fixed plating thickness of 8 ?m, a simulation result of the plating time is 18.2 minutes and a simulation result of the drilling filling rate is 51%.

[0055] As shown in FIG. 6B, the first-stage plating drilling filling process with a first current density of 0.5 ASD is performed to form a first plating layer with a thickness of 2.6 ?m; next, the second-stage plating drilling filling process with a second current density of 2 ASD is performed to form a second plating layer with a thickness of 2.6 ?m; next, the third-stage plating drilling filling process with a third current density of 1 ASD is performed to form a third plating layer with a thickness of 2.6 ?m, and a simulation result of the plating time for the three-stage plating drilling filling process is 42.42 minutes, and a simulation result of the drilling filling rate is 51.97%. It should be noted that the thickness of the first plating-layer, the thickness of second plating-layer and the thickness of third plating-layer are the same as each other, but these examples are merely for exemplary illustration, and the application field of the present invention is not limited to the above-mentioned examples. In an embodiment, the thickness of the first plating-layer, the thickness of second plating-layer and the thickness of third plating-layer can be different from each other; in an embodiment, the thickness of the first plating-layer, the thickness of second plating-layer and the thickness of third plating-layer can be partially the same or different.

[0056] Please refer to FIGS. 7A and 7B. FIG. 7A is a diagram showing a simulation result of a single-stage plating filling process with single current density, and FIG. 7B is a diagram showing a simulation result of a plating drilling filling process with different current densities, wherein the thicknesses of the plating layers in multiple stages are the same as each other.

[0057] As shown in FIG. 7A, a single-stage plating drilling filling process with a single current density of 2 ASD is performed to form a plating layer with a thickness of 20 ?m, a simulation result of the plating time is 45.45 minutes and a simulation result of the drilling filling rate is 74%.

[0058] As shown in FIG. 7B, a first-stage plating filling process with a first current density of 0.5 ASD is performed to form a first plating layer with a thickness of 6.7 ?m, a second-stage plating drilling filling process with a second current density of 2 ASD is performed to form a second plating layer with a thickness of 6.7 ?m, and a third-stage plating drilling filling process with a third current density of 1 ASD is performed to form a third plating layer of a thickness of 6.7 ?m, a simulation result of the plating time for the three-stage plating drilling filling process is 106.1 minutes, and a simulation result of the drilling filling rate is 77.07%. It should be noted that the thicknesses the first plating-layer, the second plating-layer and the third plating-layer are the same as each other, but these examples are merely for exemplary illustration, and the application field of the present invention is not limited to the above-mentioned examples. In an embodiment, the thickness of the first plating-layer, the thickness of second plating-layer and the thickness of third plating-layer can be different from each other; in an embodiment, the thickness of the first plating-layer, the thickness of second plating-layer and the thickness of third plating-layer can be partially the same or different.

[0059] The operations of the plating method of the present invention will be described in the following paragraphs. Please refer to FIG. 8, which is a flowchart of a plating method according to the present invention.

[0060] As shown in FIG. 8, the plating method of the present invention includes steps 101 to 105.

[0061] In a step 101, a substrate including at least one hole formed therein and a to-be-plated layer formed on a surface thereof is provided. In a step 102, a power supply device including a cathode and an anode is provided, the substrate is disposed on the cathode, and the power supply device is configured to supply power for plating and adjust a current density for plating. In a step 103, plating solution with metal ion is accommodated in a plating tank, and the substrate and the anode are immersed in the plating solution in the plating tank. In a step 104, the power supply device is activated and set to perform a M-th stage plating drilling filling process with a M-th current density for a M-th plating time, to form a M-th plating layer on the to-be-plated layer in the at least one hole, wherein N is a positive integer equal to or greater than 3, and M is a positive integer in a range of 1 to N. In a step 105, the power supply device is stopped supplying power, and the substrate is taken out of the plating solution to perform a cleaning and drying process.

[0062] According to above-mentioned contents, the difference between the present invention and the conventional technology is that, in the present invention, the plating system performs the N-stage plating drilling filling process in which the M-th stage plating drilling filling process with the M-th current density is performed on a hole of a substrate for the M-th plating time to form the M-th plating layer on the to-be-plated layer, wherein N is a positive integer equal to or greater than 3, and M is a positive integer in a range of 1 to N.

[0063] Therefore, the above-mentioned technical solution of the present invention is able to solve the problem that the thickness of the plating layer is too thick due to the consideration of drilling filling rate, and high line impedance and poor mechanical properties caused by pinholes generated on the surface of the electroplating layer in the etching process, so as to achieve the technical effect of providing the higher drilling filling rate than conventional plating filling technology under a condition that a total thickness of plating layers is fixed.

[0064] The present invention disclosed herein has been described by means of specific embodiments. However, numerous modifications, variations and enhancements can be made thereto by those skilled in the art without departing from the spirit and scope of the disclosure set forth in the claims.