Circuit board structure and manufacturing method thereof

Abstract

A circuit board structure and its manufacturing method are disclosed. The circuit board structure includes a substrate, a magnetic sensing element, a corrosion-resistant layer, and a through-hole metal layer. The substrate includes through-holes extending from the front side to the back side of the substrate. The magnetic sensing element is disposed on the sidewall of the through-hole in the substrate. The corrosion-resistant layer is disposed on the magnetic sensing element. The through-hole metal layer is disposed on the corrosion-resistant layer. The corrosion-resistant layer isolates the magnetic sensing element from the through-hole metal layer.

Description

Technical Field

[0001] This invention relates to circuit board structures, and more particularly to circuit board structures with corrosion-resistant layers and methods for manufacturing the same. Prior Technology

[0002] Printed circuit boards (PCBs) are widely used in various electronic devices, including computer motherboards, electrical appliances, smartphones, and automotive electronics, enabling electrical connections between various electronic components. As electronic products strive for thinner, lighter, smaller, and cheaper designs, PCBs are required to have a larger wiring area. Therefore, some issues regarding PCB structure still need to be overcome. Summary of the Invention

[0003] In some embodiments, a circuit board structure is provided. The circuit board structure includes a substrate, a magnetic sensing element, a corrosion-resistant layer, and a through-hole metal layer. The substrate includes through-holes extending from the front side of the substrate to the back side. The magnetic sensing element is disposed on the sidewall of the through-hole in the substrate. The corrosion-resistant layer is disposed on the magnetic sensing element. The through-hole metal layer is disposed on the corrosion-resistant layer. The corrosion-resistant layer isolates the magnetic sensing element from the through-hole metal layer.

[0004] In some embodiments, a method for manufacturing a circuit board structure is provided. The method includes: providing a substrate, the substrate including through-holes extending from the front side to the back side of the substrate; forming a magnetic sensing element on the sidewall of the through-hole in the substrate; forming a corrosion-resistant layer on the magnetic sensing element; and forming a through-hole metal layer on the corrosion-resistant layer. The corrosion-resistant layer isolates the magnetic sensing element from the through-hole metal layer.

[0005] To make the features of this disclosure more apparent and understandable, various embodiments are described below in conjunction with the accompanying drawings. Simple Explanation of the Diagram

[0006] By convention, some features may not be drawn to scale. In fact, the dimensions of different features may be increased or decreased for clarity of description. Figures 1A-1F are side views of a circuit board structure in process according to some embodiments of the present disclosure. Figure 2A is a side view of a circuit board structure according to some embodiments of the present disclosure. Figure 2B is a cross-sectional view of Figure 2A along line BB. Implementation

[0007] The following description provides many different embodiments. The specific elements and arrangements mentioned are merely for the simple and clear description of some embodiments of this disclosure and are intended to be illustrative rather than limiting. Furthermore, similar and / or corresponding element symbols may be used in different embodiments to identify similar and / or corresponding elements, solely for the simple and clear description of some embodiments of this disclosure, and do not represent any relationship between the different embodiments and / or structures discussed.

[0008] Furthermore, the ordinal numbers used in the specification and claims, such as "first" and "second," to modify elements are not intended to imply any prior ordinal number for that element (or those elements), nor to indicate the order of one element with another, or the order of manufacturing processes. The use of these ordinal numbers is solely to clearly distinguish one named element from another with the same name. The claims and specification may not use the same terminology; for example, the first element in the specification may be the second element in the claims.

[0009] Terms such as "connect," "interconnect," and "bond," when used in relation to joining or bonding, can refer to two structures in direct contact, or to two structures not in direct contact but with another structure positioned between them, unless otherwise defined. These terms can also include situations where both structures are movable or both are fixed. Furthermore, the terms "electrical connection" or "electrical coupling" include any direct or indirect means of electrical connection.

[0010] The following embodiments, without departing from the spirit of this disclosure, allow for the substitution, reorganization, and combination of components in multiple different embodiments to complete other embodiments. Components in each embodiment can be arbitrarily combined and used as long as they do not violate the spirit of the invention or conflict with it.

[0011] In the following text, when a material is described as "etching resistant," "acid resistant," or "alkali resistant" to a process solution, it means that the etching rate of the solution used in that process environment is less than 100 µm / s for the material. Furthermore, when a material is described as "acid resistant," it means that the etching rate of the material exposed to a solution with a pH of 2-5 is at least less than 100 µm / s; and when a material is described as "alkali resistant," it means that the etching rate of the material exposed to a solution with a pH of 9-12 is at least less than 100 µm / s.

[0012] This disclosure provides a circuit board structure and a method for manufacturing the same. The circuit board structure disclosed herein includes a corrosion-resistant layer between a magnetic sensing element and a through-hole metal layer. The corrosion-resistant layer isolates the magnetic sensing element from the through-hole metal layer. This configuration ensures that the magnetic sensing element is not affected (e.g., corroded) by acidic or alkaline process solutions during the formation of the through-hole metal layer.

[0013] Furthermore, the circuit board structure manufacturing method disclosed herein forms a etch-resistant layer on the magnetic sensing element before forming the through-hole metal layer. This etch-resistant layer isolates the magnetic sensing element from the acidic or alkaline liquids used in the through-hole metal layer formation process. This process configuration ensures that the magnetic sensing element is not affected (e.g., etched during the through-hole metal layer formation process), thereby providing better manufacturing yield and device performance.

[0014] Figures 1A-1F are side views of a circuit board structure in process according to some embodiments of this disclosure. Not all process steps of the circuit board structure may be described below for illustrative purposes. Those skilled in the art will understand that process steps known in the art may be added before, between, or after the following process steps without departing from the spirit of this disclosure.

[0015] Please refer to Figure 1A. The steps of forming the circuit board structure 100 include providing a substrate 10 and forming a through-hole 116 through the substrate 10, the through-hole 116 passing through the front side 101 to the back side 102 of the substrate 10. In some embodiments, the through-hole 116 may be formed in the substrate 10 by, for example, mechanical drilling, laser drilling, other suitable methods or combinations thereof, but this disclosure is not limited thereto.

[0016] As shown in Figure 1A, electrical connection pads 104 are formed on the front side 101 and back side 102 of the substrate 10. The electrical connection pads 104 can be conductive materials, such as aluminum (Al), copper (Cu), silver (Ag), tin (Sn), nickel (Ni), chromium (Cr), titanium (Ti), lead (Pb), gold (Au), tungsten (W), their alloys or compounds, but this disclosure is not limited thereto.

[0017] The steps for forming the electrical connection pad 104 may include, for example, electroplating, electroless plating, sputtering, lamination, coating, or a combination thereof, and may be combined with a patterning process to form the electrical connection pad 104 with the desired pattern on the front side 101 and back side 102 of the substrate 10.

[0018] As shown in Figure 1A, a magnetic sensing material 106 is filled into the through-hole 116 of the substrate 10. The magnetic sensing material 106 completely fills the through-hole 116 of the substrate 10 and directly contacts the sidewall of the through-hole 116.

[0019] In some embodiments, the magnetic sensing material 106 may be one or more ferromagnetic (or subferromagnetic) materials, including but not limited to: cobalt (Co), iron (Fe), iron(III) oxide (Fe2O3) (also known as iron oxide), iron(II) oxide (FeO) (also known as ferrous oxide) and iron(III) oxide (FeOFe2O3), nickel oxide (NiO) and iron(III) oxide (NiOFe2O3), copper(II) oxide (CuO) and iron(III) oxide (CuOFe2O3), magnesium oxide (MgO) (also known as copper oxide) and iron(III) oxide (MgOFe2O3), manganese(III) bismuthide (MnBi), nickel (Ni), manganese(III) antimonyide (MnSb), manganese(II) oxide (MnO) and iron(III) oxide (MnOFe2O3), yttrium iron oxide (Y3Fe5O12), chromium(IV) oxide (CrO2), manganese(III) arsenide (MnAs), or zinc cadmium telluride (CdZnTe) (also known as CZT), and / or any combination thereof.

[0020] In some embodiments, the magnetic sensing material 106 may be formed by, for example, chemical vapor deposition (CVD), physical vapor deposition (PVD), spin coating, lamination, or other suitable formation processes, but this disclosure is not limited thereto. In some embodiments, a planarization process, such as chemical mechanical polishing (CMP), may be performed after the formation process of the magnetic sensing material 106, so that the top and bottom surfaces of the magnetic sensing material 106 are flush with the front side 101 and back side 102 of the substrate 10, respectively.

[0021] Please refer to Figure 1B. A drilling process similar to that described above for forming the through-hole 116 is performed to form the magnetic sensing material 106 as a magnetic sensing element 106 located on the sidewall of the through-hole 116. In some embodiments, the magnetic sensing element 106 has a protruding portion 106P that protrudes from the front side 101 and the back side 102 of the substrate 10. Here, for the sake of brevity, the terms "magnetic sensing material" and "magnetic sensing element" are given the same element reference 106, but it should be understood that the magnetic sensing element 106 refers to the magnetic sensing element formed by drilling the magnetic sensing material 106.

[0022] Referring again to Figure 1B, after the magnetic sensing element 106 is formed, a corrosion-resistant material 108 is formed in the through-hole 116 of the substrate 10 and on the magnetic sensing element 106. The corrosion-resistant material 108 is used to protect the magnetic sensing element 106 from corrosion or damage by the process solution during subsequent metal layer formation processes (e.g., the subsequent process of forming the through-hole metal layer 112).

[0023] As shown in Figure 1B, the corrosion-resistant material 108 is formed in the through hole 116 and directly contacts and completely covers the magnetic sensing element 106. Specifically, as shown in Figure 1B, the corrosion-resistant material 108 is formed such that the top surface 108T and the bottom surface 108B completely cover the upper end surface and the lower end surface ES of the magnetic sensing element 106, and the corrosion-resistant material 108 also completely covers the side surface SS of the magnetic sensing element 106 near the center C of the through hole 116.

[0024] Please refer to Figure 1C. In some embodiments, a drilling process similar to that described above for forming the through hole 116 and the magnetic sensing element 106 is performed to form the corrosion-resistant material 108 as a corrosion-resistant layer 108. As with the aforementioned "magnetic sensing material" and "magnetic sensing element", the "corrosion-resistant material" and "corrosion-resistant layer" also use the same element symbol 108.

[0025] The material of the corrosion-resistant material 108 is selected based on the process solution (e.g., electroplating solution) used in the subsequent metal layer formation process (e.g., the process of forming the through-hole metal layer 112). (e.g., selecting a material with a certain degree of corrosion resistance to the process solution) and the thickness T1 of the corrosion-resistant layer 108 can be adjusted according to the maximum etching rate of the material by the solution used in the metal layer formation process in conjunction with the time of the metal layer formation process.

[0026] In some embodiments, the corrosion-resistant material 108 may be formed by production methods such as filling, pressing, or coating.

[0027] In the subsequent metal layer formation process, acid solutions such as sulfuric acid or hydrochloric acid are used for the through-hole metal layer. In some embodiments, the corrosion-resistant material 108 can be selected from acid-resistant materials that can resist acid solutions, such as perforated oil film or ABF insulating film.

[0028] Referring to Figure 1D, a seed layer 110 is formed on the corrosion-resistant layer 108, located between the corrosion-resistant layer 108 and the via metal layer 112 to be formed thereon. In embodiments with the seed layer 110, the seed layer 110 may serve as a conductive substrate to increase the thickness uniformity of the via metal layer 112 subsequently formed thereon. The material of the seed layer 110 includes copper, aluminum, nickel, gold, palladium, similar materials, or combinations thereof. The method of forming the seed layer 110 includes an electroless plating process.

[0029] In some embodiments, a barrier layer (not shown) may be formed on the corrosion-resistant layer 108 after the formation of the corrosion-resistant layer 108 and before the formation of the seed layer 110, depending on the circumstances. The barrier layer is used to block the diffusion of metal atoms when the through-hole metal layer 112 is subsequently formed. The barrier layer is a barrier material such as Ti or TiN.

[0030] However, it is worth noting that the materials of the barrier layer and the seed layer 110 are usually not corrosion resistant. Therefore, the barrier layer or the seed layer 110 alone cannot effectively protect the magnetic sensing material 106 from the process solution and corrosion during the through-hole metal layer 112 process.

[0031] Please refer to Figure 1E. In some embodiments, a via metal layer 112 is formed on the etch-resistant layer 108 or the seed layer 110 (if present). During the formation of the via metal layer 112, the magnetic sensing element 106 is completely covered by the etch-resistant layer 108 and does not come into contact with the solution used in the formation of the via metal layer 112. In other words, the configuration of the etch-resistant layer 108 ensures that the magnetic sensing element 106 is not damaged or corroded by the process solution (e.g., acidic or alkaline plating solution) during the formation of the via metal layer 112. In this way, the configuration of the etch-resistant layer 108 ensures the integrity of the magnetic sensing element 106, thereby improving the manufacturing yield of the circuit board structure 100 and the device performance.

[0032] As shown in Figure 1E, the through-hole metal layer 112 completely covers the seed layer 110 and is electrically connected to the electrical connection pad 104 across the corrosion-resistant layer 108. The electrical connection pad 104 also contacts the protruding portion 106P of the magnetic sensing element 106 and is inserted between the through-hole metal layer 112 and the substrate 10. The magnetic sensing element 106 includes a stack of corrosion-resistant layer 108, seed layer 110 and through-hole metal layer 112, which are formed as a pair of C-shaped contours facing away from each other and with their openings facing the substrate 10.

[0033] In some embodiments, the material of the through-hole metal layer 112 may be a suitable conductive material, such as aluminum (Al), copper (Cu), brass, phosphor bronze, beryllium alloy, or oxygen-free copper, their alloys or compounds, or other suitable metallic materials or combinations thereof, but this disclosure is not limited thereto.

[0034] In some embodiments, the through-hole metal layer 112 can be formed, for example, by electroplating or electroless plating. Without the corrosion-resistant layer 108, the plating solution can easily penetrate the seed layer 110 and / or barrier layer to contact the magnetic sensing element 106, thereby causing corrosion or damage. Therefore, the corrosion-resistant layer 108 disclosed herein is made of a material that is not corroded by the plating solution (e.g., has acid or alkali resistance), thus isolating the magnetic sensing element 106 from the plating solution when the substrate 10 is placed in the plating solution, preventing damage or corrosion from the plating solution. In other words, the corrosion-resistant layer 108 isolates the plating solution from the magnetic sensing element 106 during the electroplating process, thus isolating the through-hole metal layer 112 formed by electroplating from the magnetic sensing element 106. Specifically, in one embodiment, a perforated oil film or an ABF insulating film is selected as the material for the corrosion-resistant layer 108 according to such an electroplating process.

[0035] Please refer to Figure 1F for the through-hole metal layer. The filling layer 114 in the through-hole 116 can be formed by printing, spin coating, lamination, other suitable methods, or combinations thereof. In some embodiments, the material of the filling layer 114 may include paper phenolic resin, composite epoxy resin, polyimide resin, glass fiber, ABF film (Ajinomoto Build-up Film), polyphenylene (PPE), polypropylene (PP), other suitable insulating materials, or combinations thereof.

[0036] In some embodiments, a planarization process, such as chemical mechanical polishing (CMP), may be performed after the filling layer 114 is formed, so that the top and bottom surfaces of the filling layer 114 are flush with the top and bottom surfaces of the through-hole metal layer 112, respectively.

[0037] Figure 2A is a side view of a circuit board structure according to some embodiments of the present disclosure. Figure 2B is a cross-sectional view of Figure 2A along line BB. It should be understood that the structural features described above in conjunction with each process stage are all present in the formed circuit board structure 100, and will not be described again here.

[0038] Referring to Figure 2A, the circuit board structure 100 includes a substrate 10, an electrical connection pad 104, a magnetic sensor 106, a corrosion-resistant layer 108, a seed layer 110, a via metal layer 112, and a filler layer 114. In some embodiments, the circuit board structure 100 can serve as, for example, an inductor structure, with the magnetic sensor 106 acting as an inductor coil within the structure to generate an induced current when other magnetic components move relative to it in a physical position. Therefore, the magnetic sensor 106 is not necessarily electrically connected to the via metal layer 112.

[0039] Referring to Figure 2B, the filler layer 114, through-hole metal layer 112, seed layer 110, corrosion-resistant layer 108, and magnetic sensing element 106 are arranged in a multi-layered coaxial structure from the center C of the through-hole 116 in a concentric circle pattern in the cross-sectional view. Since the corrosion-resistant layer 108 isolates the magnetic sensing element 106 from the process solution during the formation of the through-hole metal layer 112, in this coaxial structure, the corrosion-resistant layer 108 separates the through-hole metal layer 112 and the magnetic sensing element 106. Although in some embodiments a seed layer 110 is also disposed between the through-hole metal layer 112 and the magnetic sensing element 106, the seed layer 110 cannot replace the function of the corrosion-resistant layer 108 in ensuring that the solution during the formation of the through-hole metal layer 112 does not contact the magnetic sensing element 106. This is because the seed layer 110 production process involves acidic or alkaline solutions, which would corrode the magnetic sensing element 106.

[0040] In summary, this disclosure provides a circuit board structure and its manufacturing method, wherein the circuit board structure has a corrosion-resistant layer between a magnetic sensing element and a via metal layer. The corrosion-resistant layer isolates the magnetic sensing element from the via metal layer. The material of the corrosion-resistant layer is selected based on the formation process of the via metal layer (e.g., selecting an acid-resistant or alkali-resistant material based on the formation process of the via metal layer). In this configuration, the corrosion-resistant layer ensures that the magnetic sensing element does not come into contact with the process solution and is not damaged (e.g., corroded by the process solution) during the formation of the via metal layer. This not only improves the manufacturing yield of the circuit board structure but also enhances the device performance of the circuit board structure.

[0041] Furthermore, the circuit board structure manufacturing method disclosed herein involves forming a corrosion-resistant layer on the magnetic sensing element before forming the through-hole metal layer. The corrosion-resistant layer completely covers the magnetic sensing element to ensure that the process solution for forming the through-hole metal layer does not contact the magnetic sensing element, thereby preventing damage to the magnetic sensing element from the process solution (e.g., electroplating solution) used in forming the through-hole metal layer. This manufacturing process also improves the circuit board structure manufacturing yield and simultaneously provides better device performance.

[0042] The above outlines several embodiments to enable those skilled in the art to better understand the viewpoints of the disclosed embodiments. Those skilled in the art should understand that other processes and structures can be designed or modified based on the disclosed embodiments to achieve the same purpose and / or advantages as the embodiments described herein. Those skilled in the art should also understand that such equivalent processes and structures do not depart from the spirit and scope of this disclosure, and that various changes, substitutions, and replacements can be made without departing from the spirit and scope of this disclosure.

[0043] 100: Circuit Board Structure 10:Substrate 101: Front side of substrate 102:Backside of substrate 104: Electrical connection pad 106: Magnetic sensing element / magnetic sensing material 106P: Highlighted Section 108: Corrosion-resistant layer / corrosion-resistant material 108T: Top surface of corrosion-resistant layer 108B: Bottom surface of corrosion-resistant layer 110: Seed layer 112: Through-hole metal layer 114: Fill layer 116: Through hole T1: Thickness ES: Magnetic induction element end face SS: Side of magnetic sensing element C: Center of through hole BB: Section X:X direction Y: Y direction Z:Z direction

Claims

1. A circuit board structure, comprising: A substrate includes a through-hole extending from a front side to a back side; a magnetic sensor disposed on the sidewall of the through-hole; a corrosion-resistant layer directly contacting and covering the magnetic sensor, wherein the corrosion-resistant layer has a top surface and a bottom surface located on opposite end faces of the magnetic sensor, and the corrosion-resistant layer completely covers a side of the magnetic sensor near the center of the through-hole; a seed layer disposed on the corrosion-resistant layer; and a through-hole metal layer disposed on the seed layer, wherein the corrosion-resistant layer isolates the magnetic sensor from the through-hole metal layer, and the seed layer and the through-hole metal layer are disposed on the side of the corrosion-resistant layer near the center of the through-hole.

2. The circuit board structure as described in claim 1, wherein, in a side view, the corrosion-resistant layer completely covers the opposite end faces of the magnetic sensing element and the side face near the center of the through hole.

3. The circuit board structure as claimed in claim 1, wherein the magnetic sensing element has a protruding portion protruding from the front and back sides of the substrate.

4. The circuit board structure as described in claim 1 further includes an electrical connection pad disposed on the front and back sides of the substrate, wherein the electrical connection pad contacts a protruding portion of the magnetic sensing element and is inserted between the through-hole metal layer and the substrate.

5. The circuit board structure as described in claim 4, wherein the through-hole metal layer spans the corrosion-resistant layer and is electrically connected to the electrical connection pad.

6. The circuit board structure as described in claim 1 further includes a filler layer (114) disposed in the through hole of the substrate.

7. A method for manufacturing a circuit board structure, comprising: A substrate is provided, including a through hole extending from a front side to a back side of the substrate; A magnetic sensing element is formed on the sidewall of the through hole in the substrate; a corrosion-resistant layer is formed on the magnetic sensing element, wherein the corrosion-resistant layer has a top surface and a bottom surface located on opposite end faces of the magnetic sensing element, and the corrosion-resistant layer completely covers a side of the magnetic sensing element near the center of the through hole; a seed layer is formed on the corrosion-resistant layer; and a through-hole metal layer is formed on the seed layer, wherein the corrosion-resistant layer isolates the magnetic sensing element from the through-hole metal layer, and the seed layer and the through-hole metal layer are formed on the side of the corrosion-resistant layer near the center of the through hole.

8. A method for manufacturing a circuit board structure as described in claim 7, wherein the step of forming the through-hole metal layer includes: Performing an electroplating process to form the through-hole metal layer on the seed layer includes: after forming the seed layer, placing the substrate in an electroplating solution, wherein the corrosion-resistant layer isolates the magnetic sensing element from the electroplating solution during the period the substrate is placed in the electroplating solution.

9. A method for manufacturing a circuit board structure as described in claim 7, wherein the corrosion-resistant layer directly contacts and covers the magnetic sensing element.

10. A method of manufacturing a circuit board structure as claimed in claim 7 or 9, wherein in a cross-sectional view, the corrosion-resistant layer completely covers the opposite end faces of the magnetic sensing element and the side face of the magnetic sensing element near the center of one of the through holes.

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