Method and apparatus for matching inductors through a substrate carrier or core

Abstract

This specification presents a method for fabricating an inductor or inductor pair through a substrate, such as a substrate core or carrier. The inductor has at least one winding that connects through the substrate. The inductor suffers from loss performance due to the winding penetrating the substrate, but this allows for placement according to a common center of gravity approach during manufacturing and in use after manufacturing. This produces nearly identical inductors suitable for matching or pairing.

Description

[Technical Field]

[0001] The general field of the present invention relates to the field of magnetics, and more particularly to methods and apparatus for matching inductors. [Background technology]

[0002] Discrete inductors are typically sold individually, or alternatively, constructed in large batch sizes and then singulated. The process of individually testing and packaging the inductors results in each component having specific performance characteristics when placed on a printed circuit board. These performance characteristics cannot be predicted to be better than the overall process tolerances, which are often as high as ±10% to ±20%.

[0003] In many cases, discrete inductors are typically placed next to an integrated circuit (IC), for example in a DC / DC converter circuit. Therefore, the IC manufacturer has no additional knowledge of the performance and tolerance of the external inductor beyond the min / max specifications provided by the inductor manufacturer. Therefore, IC designers must design their ICs to withstand worst-case tolerances of ±10% to ±20% in most cases.

[0004] To make matters worse, many of the latest power conversion architectures introduced use multiphase / multichannel circuits containing multiple uncoupled inductors, one or more coupled inductors, and transformers to mitigate the significant thermal issues of high-performance processors, improve power efficiency in chargers, and reduce the overall size of the power conversion solution. These types of multiphase / multichannel designs must consider performance mismatches between magnetic components to ensure that the current flow through all channels is balanced. Balancing the current flow is necessary for many reasons, including ensuring even distribution of heat dissipation, improving component reliability, and reducing solution size. Instead of balancing the current flow, each channel can be designed to worst-case tolerance specifications. This results in a 2x to 10x increase in solution size and a proportional increase in manufacturing costs.

[0005] Additionally, all power circuits that have magnetic components such as inductors, transformers, or any of their variations in single or multiple forms must deal with tolerance and mismatch issues. These power circuits are found in discrete DC / DC converters, DC / DC modules with integrated magnetic components, and power management integrated circuits (PMICs) incorporating multi-phase buck, boost, or buck-boost converter ICs.

[0006] Magnetic components are often the largest components in a power conversion circuit. Therefore, to reduce size, many designers desire smaller inductors. However, the smaller the inductors, the more difficult it is to match or couple them without generating high electronic noise and losing power conversion efficiency and stability. A matched or coupled pair of inductors has difficulty ensuring current balance when their electrical characteristics—inductance (L), resistance (R), and capacitance (C)—vary greatly. This problem arises when an application designed to use two inductors of the same value (e.g., a coupled-inductor DC / DC converter, or LLC converter) must ensure that the currents flowing through each inductor are approximately the same.

[0007] The adverse effects of mismatch can arise because a pair of inductors are not physically identical due to manufacturing tolerances. This physical mismatch has a greater effect as inductors become smaller, and it places a practical limit on how small a pair of inductors can be in a matched or coupled system.

[0008] Unfortunately, current techniques for matching or coupling inductors present design challenges by being time-intensive or requiring mismatch compensation. For example, a matched inductor is valid and useful when the inductors are in a matching circuit, i.e., when their inductance, resistance, and capacitance are closely matched. Currently, at least two processes are used to match inductors: "match screening" and "process matching." Match screening involves screening inductors with similar performance, accepting a reduced yield and certain performance differences. Process matching involves forming inductors closely together using the same process steps, resulting in inductors with LRC values ​​that are as identical as possible and achieving high yields.

[0009] However, to date, both match screening and process matching have failed to produce identical inductor pairs. Screening to pair nearly identical inductors is time-consuming and accumulates errors and tolerances from both the screening and manufacturing processes. Match processing suffers from the manufacturing tolerance issues mentioned above. In either process, designers and engineers must either accept the degraded performance of the inductor pair as a marginal value or implement complex compensation schemes for the mismatched but paired inductors.

[0010] Eliminating or reducing manufacturing tolerances, or the effects of manufacturing tolerances, allows for smaller matched or coupled inductors to be produced by relying on screening methods.

[0011] However, over the years, many attempts have been made to form magnetic cored inductors in both printed circuit boards (PCBs) and semiconductor packages, but all have failed economically due to large manufacturing tolerances and an inability to achieve sufficient performance compared to discrete solutions. Summary of the Invention

[0012] By arranging the inductor windings in a novel way that degrades the performance of the individual inductors, new layouts are introduced that significantly reduce the mismatch in matched or coupled inductors while generally reducing the area required for integrated inductors, allowing matched and coupled inductors to be used in smaller, more sensitive circuits.

[0013] Accordingly, disclosed herein is a method for fabricating a matching inductor, the method comprising: providing a substrate (typically a substrate core), forming at least two through vias that penetrate from a first surface of the substrate to a second surface of the substrate opposite the first surface of the substrate, plating an inductor coil along the length of the through vias to enable electrical connection through the through vias, and plating a first inductor on the first surface of the substrate and a second inductor identical to the first inductor on the second surface of the substrate, such that the first inductor and the second inductor are electrically connected by the inductor coil passing through the through vias.

[0014] This results in the formation of a single inductor, also disclosed herein. This inductor has a portion of the coil on one side of the substrate and another portion of the coil on the other side of the substrate (usually the opposite side of the substrate in practice). This inductor can occupy half the space of an inductor plated in a single layer. This inductor layout is made possible by placing the coil windings through the substrate itself, which causes the inductor's performance to degrade depending on the number of coils that penetrate the substrate. Of note here is the fact that the inductor windings penetrate the substrate. In one exemplary embodiment, the substrate is, for example, a printed circuit board. Other examples of substrates include, but are not limited to, Ajinomoto® Build Film or a printed circuit board core, and further examples of substrates are described later in this application.

[0015] The penetration of the substrate by the inductor winding can also be used to connect two inductors to each other. Accordingly, a method for manufacturing an inductor is further disclosed herein. The method includes providing a substrate, forming at least one through via that penetrates from a first surface of the substrate to a second surface of the substrate opposite the first surface of the substrate, plating an inductor coil along the length of the through via to enable electrical connection through the through via, and plating a first portion of the inductor on the first surface of the substrate and a second portion of the inductor on the second surface of the substrate, such that the first portion of the inductor and the second portion of the inductor are electrically connected by the inductor coil that passes through the through via.

[0016] It should be noted that this method of connecting inductors can be utilized to connect inductors constructed from at least one first portion and at least one second portion of a coil, the inductor itself separated by a substrate. Many types of inductors can be plated and connected in this manner. Furthermore, multiple inductors can be connected, matched, or coupled in this manner, resulting in an inductor pair containing more than two inductors.

[0017] In particular embodiments of the substrate, the substrate may be a printed circuit board core or a magnetic core. Thus, all inductors may have a core, which may be, for example, nickel-iron. Inductors may be constructed from a variety of materials, including copper or hybrid materials. Inductors may also be incorporated into the system as matched or coupled inductors, or in other paired configurations.

[0018] It is useful to lay out paired inductors according to a "common center of gravity" approach. This common center of gravity approach helps ensure that identical inductors are formed and that paired inductors respond similarly to environmental stresses (including but not limited to heat). For example, three inductors can be placed circumferentially at 120-degree intervals, and four inductors can be placed at 90-degree intervals. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a cross-sectional view showing four inductors arranged according to the common center of gravity approach. [Figure 2] FIG. 2 is a cross-sectional view showing a cross section of two inductors paired together. [Figure 3] FIG. 3 is a cross-sectional view showing an example of the layout of the case 1. [Figure 4] FIG. 4 is a cross-sectional view showing an example of the layout of the case 2. [Figure 5] FIG. 5 is a cross-sectional view showing the layout of the inductor in the case 3. As shown in FIG. [Figure 6] FIG. 6 is a cross-sectional view showing the layout of the inductor in the case 4. As shown in FIG. [Figure 7] FIG. 7 is a cross-sectional view showing the initial starting state of the coupled inductor in all cases. [Figure 8] FIG. 8 is a cross-sectional view of the carrier with vias formed and plated. [Figure 9] FIG. 9 is a flowchart showing an example of a manufacturing process. [Figure 10] FIG. 10 is a flowchart showing another example of the manufacturing process. [Figure 11] FIG. 11 is a cross-sectional view showing an example of the layout of Case 2 (four inductors). [Figure 12A] FIG. 12A is a bottom view of an example of Case 2, showing a bottom view of a layer with three inductor coil sections already arranged according to the common center of gravity principle. [Figure 12B] FIG. 12B is a top view of the same example of Case 2 as FIG. 12A, showing the upper inductor coil portion. [Figure 13A] FIG. 13A is a top view showing four inductor coil sections arranged in a 90 degree cross (+) configuration. [Figure 13B] FIG. 13B shows a bottom view of the same example of Case 2 as FIG. 13A. [Figure 13C] FIG. 13c is a schematic diagram showing a symbolic interpretation of FIGS. 13a and 13b. [Figure 13D] FIG. 13d is a schematic diagram showing an example of a chart of the order of inductor pairs. [Figure 14] 10 is a diagram showing the area of ​​the substrate core in comparison between Cases 1 and 3 and Case 0. [Figure 15] FIG. 10 is a schematic diagram showing the required amount of substrate core area when the core is divided. [Figure 16] FIG. 16 is a cross-sectional view showing multiple inductors, each of which may be paired with an inductor directly opposite. [Figure 17] FIG. 17 is a cross-sectional view showing an example in which heat source 120 is located above and centered between inductors 1701 and 1702. [Figure 18] FIG. 18 is a cross-sectional view showing a system-influencing element 1820 positioned above an inductor and a system-influencing element 1821 positioned below the same inductor. [Figure 19] FIG. 19 is a cross-sectional view showing an example in which the intermediate inductor (1901) of Case 1 is combined with two inductor pairs (1901, 1904) and (1903, 1902) of Case 3. DETAILED DESCRIPTION OF THE INVENTION

[0020] With regard to matched or coupled inductors, the inventors have noted the following: For inductors to be perfectly matched, the inductors do not need to be inductors with perfect performance, but instead, they need to be identical inductors. Because these identical inductors have the same performance issues, the design margin in the compensation scheme is greatly simplified. For example, one can compensate both inductors of a pair by 10%, as opposed to compensating one inductor by 10% and the other by 20%. This compensation scheme can then be used to offset the adverse effects that degrade the inductor's performance. This ease of compensation creates room for maneuvering inductor performance.

[0021] Essentially, "breaking" an inductor allows for perfectly matched inductors, where the inductor has at least one winding that is plated through the substrate or core. This degrades the inductor's performance. In fact, plating too many windings through the substrate can render the inductor unusable. However, with this technology, it is suddenly possible for inductors to be plated on both sides of the substrate, and even for multiple inductors to be plated while still connected through the substrate. This allows for a "common centroid approach" to the inductor plating layout, not only in the final component design but also in the inductor manufacturing process.

[0022] The common center of gravity approach makes it possible to create nearly identical inductors. For inductors plated on the same surface of the board, this method is not an option. Let's take a look at what the common center of gravity approach makes possible.

[0023] 1 shows four inductors arranged according to a common center of gravity approach. Inductor 101 is coupled to inductor 104, and inductor 102 is coupled to inductor 103. Each inductor is coupled through via 140 through substrate 150. Heat source 120 is positioned above and laterally offset from the inductors. This situation can occur both in an out-in-the-world system where multiple inductors are plated in the same electroplating bath, and during manufacturing.

[0024] In the electroplating bath, the heat reaching inductors 101 and 102 from heat source 120 is different, and this difference causes different plating rates for inductors 101 and 102, creating a physical mismatch. This is also true for inductors 101 and 102 in this example. However, inductors 103 and 104 are coupled to inductors 102 and 103, respectively. The total heat applied to each coupled pair is the same, resulting in inductor pairs that have the same plating rates as each other. Outside the plating bath, each inductor has the same average thermal expansion, for example, due to heat source 120, and therefore remains proportionally identical.

[0025] "Physically identical inductor pairs receive identical compensation, making the design process much easier for engineers. Furthermore, this process can be used on single inductors as well, creating inductors with identical coil-to-coil matching. This allows inductor layout to reach new levels and realms previously unreachable."

[0026] 2 shows a cross section of two inductors paired together: inductor 201 and inductor 202. Inductor 201 and inductor 202 form an inductor pair, with coil 210 for inductor 202 and coil 211 for inductor 201 on opposite sides of substrate 150. Note that the coils for inductor 201 and inductor 202 are offset. This offset extends the common center of gravity principle by allowing each pair of inductor coils to be built around a common point 160 and connected to the same center 160.

[0027] These inductor pairs can be matched or coupled inductors, and are suitable for inductor coupling, transformer, or multiphase designs. Building inductors on both sides of the substrate allows the inductors to be easily integrated into semiconductor packages or printed circuit boards. This is very useful because it is common in the semiconductor industry to build semiconductor packages by stacking layers around the top surface of a planar substrate core. By allowing inductors to be plated on the top and bottom surfaces of the same core, it becomes easy to incorporate compensating matching inductor circuits. This simplifies the design effort, improves power efficiency, and reduces system costs.

[0028] Because the common center of gravity approach is applicable and scalable, these systems can incorporate multiple inductor pairs. This is useful because one widespread application of matching inductors is in power management integrated circuits (ICs), such as multiphase buck converter ICs, boost converter ICs, or buck-boost converter ICs. Here, there are multiple phases requiring inductor pairs, with the minimum number of phases being two, and even numbers such as 2, 4, 6, and so on being common for improving ripple and noise. As another example, an RF differential amplifier, commonly referred to as an LNA (low noise amplifier), has an inductor pair in each branch of its two LC circuits (tank circuits). In general, the inductors presented herein are suitable for coupled inductors, transformers, or multiphase designs.

[0029] There are two general categories of layouts created by allowing inductor windings to penetrate the substrate. The first category is for individual inductors split through the substrate, and the second category is for multiple inductors separated by a substrate but still paired with windings that penetrate the substrate. Each category has two cases: two cases involve splitting individual inductors, and the remaining two involve connecting two or more inductors through the substrate. However, it should be noted that these general categories, and even cases, can be combined in a variety of ways. It should also be noted that these inductors can penetrate part of the substrate, such as the substrate core, and thus function as the substrate itself in subsequent manufacturing or design (e.g., in printed circuit board design).

[0030] The first case we will discuss is where a single inductor is split across a substrate. For example, one set of inductor coils is formed on the top surface of the substrate core, and another set of inductor coils is formed on the opposite side of the substrate. This can be called Case 1.

[0031] FIG. 3 shows an example of a layout for Case 1. Here, there are inductor coils 301 on both sides of the substrate 150, and these coils 301 belong to the same inductor. Two windings 140 pass through the substrate 150. In this example, the coils 301 are held within the build-up film 160. As can be seen from FIG. 1, in this case the inductor simply has at least one winding passing through the substrate, connecting the coils together. It has been found that three windings passing through the substrate may be optimal.

[0032] The second case is based on case 1 and is arranged according to the common center of gravity principle, meaning that the inductors are built into a common center of gravity design and are shaped to maintain that common center of gravity design.

[0033] Figure 4 shows an example layout for Case 2. Here, the inductor coils 401 on both sides of the substrate 150 belong to the same inductor. However, the coils 401 are offset so that they rotate around a common center of gravity 160 (the center of gravity is only a location and is not physically distinct). By completely offsetting the coils 401 so that they do not overlap, it is possible to place another set of coils in the available space according to the case design, as shown in Figure 2, to form a case for multiple inductors.

[0034] The second category of layouts involves multiple inductors that are not halved, which allows for the creation of multiple identical inductors.

[0035] 5 shows the inductor layout for Case 3, where inductors 501 and 502 are separated by substrate 150 but are still connected by a through-substrate winding 140. These inductors may have their own unique core 510. Because each inductor has its own layer for a given horizontal area, excluding any through-substrate windings used to pair the inductors, the overall inductor area for paired inductors is reduced by half for an even number of inductors and by more than half for an odd number of inductors when compared to a single-level inductor layout.

[0036] FIG. 6 shows the layout of inductors for Case 4, where inductors 601 and 602 are separated by substrate 150 and rotationally offset about a common center of gravity 160 (as in FIG. 4, the center of gravity is only a location and is not physically distinct). As shown here, although the inductors are generally offset, they are still configured as pairs. This configuration allows another set of Case 3 inductors to be placed according to the common center of gravity approach, thereby providing two inductor pairs placed according to the common center of gravity approach.

[0037] The advantages of each case are discussed below, but first, it is important to note that there is no reason not to have an odd number of inductors, and each case can accommodate an odd number of inductors or odd number of inductor pairs while still providing area savings.

[0038] Table 1 below shows the area savings for a given number of matching inductors, where S1 represents the area of ​​a single layer inductor (not the present invention), and n=1, 2, 3, ...ect.

[0039] [Table 1]

[0040] As can be seen from this table, the examples of Case 1 and Case 3 require less space for both odd and even inductors than if the inductors were constructed on a single layer. In fact, by occupying both the top and bottom sides of the carrier, multiple inductors can be packed into a smaller two-dimensional area. Thus, by comparison, a circuit can halve the total area of ​​matched horizontal inductors for a given number of inductors in any given application.

[0041] For inductors in Cases 2 and 3, the problem is more complex. In general, inductors in Case 2 occupy more horizontal space than inductors built on a single layer. On the other hand, a pair of inductors in Case 3 occupies the same horizontal space as two inductors built on the same layer. However, when another inductor is placed, as shown in Figure 4, the area does not increase for Case 1, so the two inductors in Case 2 can be placed in the same horizontal space as two inductors built on the same level. For Case 2, adding another pair of inductors to the system does not increase the horizontal area, as shown in Figure 6. As a result, the two inductor pairs in Case 4 occupy half the horizontal space of an equivalent set of four inductors placed on the same layer.

[0042] However, even if Cases 2 and 4 do not save horizontal space, they still benefit from the advantages of identically formed inductors. This is true for all four cases because the inductors are copies of each other and are connected together. For example, compensation mismatch issues are greatly reduced. Thus, for example, in a matched inductor pair, both inductors require the same compensation. This contrasts with, say, one inductor requiring 5% compensation and the other requiring 10% compensation. Also, inefficiencies due to thermal expansion affecting one inductor pair or one inductor coil more than the other are further reduced.

[0043] Having explained the basics of the layouts for Cases 1 to 4, we can now discuss how these layouts are manufactured and then explain the advantages of each layout in more detail.

[0044] In all cases presented herein, the inductor is formed on a substrate. Thus, FIG. 7 illustrates the initial starting state of the coupled inductor in all cases, i.e., substrate 150. In at least one exemplary embodiment, this substrate is what is commonly known in the industry as a substrate core. However, the substrate may be selected based on a variety of factors (e.g., for improved mechanical, thermal, or electrical properties, or cost) and may be selected from a variety of core types (including, but not limited to, epoxy, fiberglass, Ajinomoto Build-Up Film, silicone, polymer, various films, or any cores identical or similar to those used in the printed circuit board, semiconductor package, semiconductor wafer, or lamination industries). In at least one exemplary embodiment, the inductor is built on a carrier. This carrier may be, but is not limited to, a material such as FR-4 or other epoxy-glass. Any carrier common in the industry is suitable to serve as the carrier herein. It will be understood that in some exemplary embodiments, the substrate may be a multilayer substrate.

[0045] FIG. 8 shows a carrier with vias 140 formed and plated. The vias 140 are formed, for example by drilling, to allow inductors to be connected and paired through the substrate. Once formed, the vias are plated with a material that allows current to be transmitted through the vias. This can be the windings of an inductor, as this allows magnetic flux to be easily coupled through the substrate. This gives the inductors or inductor coils on either side of the carrier properties as matching or coupled inductors. (Coupled inductors are coupled by the transfer of magnetic flux from one winding pair to the other.)

[0046] Here, the categories diverge with regard to plating methods. As shown in Figure 9, plating in Cases 1 and 2 involves selecting a substrate, forming and plating a coil in a via, plating a portion of the inductor coil on one side of the substrate, and plating the remainder of the inductor coil on the other side. On the other hand, as shown in Figure 10, what is plated on each side is actually multiple independent inductors, rather than a portion of an individual inductor.

[0047] In Cases 1 and 2, a portion of the inductor's coil is plated onto the substrate. An example of the results for Case 1 is shown in Figure 3, where a single inductor 301 is formed, with half of the inductor 301 located on one side of the substrate 150 and the other half located on the opposite side of the substrate 150. At least one via 140 is shown plated with the inductor winding, although the via 140 need not be plated in the location shown.

[0048] In the example of Case 1 in Figure 3, the coil can be plated to any non-zero percentage on the top side and any non-zero percentage on the bottom side, but note that half of the inductor coil is plated on the top side of the substrate and the other half is plated on the bottom side of the substrate. Forming the inductor in this half-and-half configuration minimizes horizontal space.

[0049] As mentioned above, Figure 4 shows an example of Case 2 in which inductor 1 is bisected by substrate 150. A defining feature of Case 2 is that the inductor coils are also offset. This offset allows the common center of gravity principle to be applied even when a system includes multiple inductors or multiple inductors are paired. It will be understood that individual inductors in Case 1 and Case 2 can be paired with other inductors.

[0050] As mentioned above, Figure 2 shows two inductors in Case 2, inductor 201 and inductor 202. Inductor 201 and inductor 202 are paired with each other in a common center of gravity approach. Inductors 201 and 202 are arranged such that coil 210 (i.e., part of inductor 201) faces coil 211 (i.e., part of inductor 202) across substrate 150. This arrangement centers the inductors around point 160. Multiple inductors can be matched or coupled through at least one winding passing through at least one via.

[0051] However, this approach is not limited to two inductors, as Figure 11 shows four inductors (i.e., inductor 1101, inductor 1102, inductor 1103, and inductor 1104). As mentioned above, Case 2 is not the optimal case for space saving, but by utilizing this extension to multiple inductors, it can be seen that Case 2 can accommodate unique inductor layouts.

[0052] To make this easier to understand, let's switch from a cross-sectional view to a top view (bottom view). For reference, FIG. 12a shows a bottom view of a layer with three inductor coil sections already arranged according to the common center of gravity principle. This is the bottom layer of an example of Case 2. FIG. 12b is a top view of the same example of Case 2, showing the upper inductor coil section. Here, it can be seen that the coil belongs to one of three inductors (i.e., inductor 1201, inductor 1202, and inductor 1203). The inductors are stacked as follows: the top of inductor 1201 is placed above the bottom of inductor 1203, the top of inductor 1202 is placed above the bottom of inductor 1201, and the top of inductor 1203 is placed above the bottom of inductor 1203. Essentially, the top and bottom of each inductor are offset by one.

[0053] However, things can get even more complicated. This results in the configurations shown in Figures 13a and 13b. Figure 13a shows a top view of four inductor coil sections arranged in a ninety-degree plus configuration. Inductors 1301 and 1302 share a cross protrusion 1310. Inductors 1303 and 1304 share a cross protrusion 1311. Inductors 1305 and 1306 share a cross protrusion 1312. Inductors 1307 and 1308 share a cross protrusion 1313.

[0054] FIG. 13b shows a bottom view of the same Case 2 example. Here, each inductor is offset from its original position, so that in the bottom layer, inductor 1307 and inductor 1308 share a cross protrusion 1310. Inductor 1301 and inductor 1302 share a cross protrusion 1311. Inductor 1304 and inductor 1303 share a cross protrusion 1312. Inductor 1305 and inductor 1306 share a cross protrusion 1312. Here, for example, inductor 1301 is paired with inductor 1306, inductor 1302 is paired with inductor 1305, inductor 1303 is paired with inductor 1308, and inductor 1304 is paired with inductor 1307. For ease of understanding, FIG. 13c shows a symbolic interpretation of FIGS. 13a and 13b. Here, the numbers within the crosses indicate the order and position of the inductors. The subscripted numbers indicate the lower inductor sections. FIG. 13d shows an example chart of the inductor pair ordering, although the ordering can be varied.

[0055] It will be appreciated that this is an optimal configuration, and Case 2 allows for the types of layouts shown in Figures 12a-12b and 13a-13d. However, it should be noted here that any portion of the inductor windings can be placed on the top surface and any remaining portion on the bottom surface. These winding portions do not need to be contiguous, but can alternate from the top surface to the bottom surface and back to the top surface again. To optimize the matching inductors, each inductor must be the same length, and their placement is guided by a common center of gravity approach. Therefore, a wide range of layout possibilities exists within each case.

[0056] It can be seen that splitting the inductor results in a significant reduction in the area of ​​the substrate core. Figure 14 compares Cases 1 and 3 with Case 0, which is not part of this invention, where the inductor is plated on only one side of the substrate core.

[0057] 14, N represents the number of inductors, and the area of ​​the board core is determined by the length and width of the board core. Therefore, for example, in the case of N3, Case 0 requires a core area large enough to hold three inductors side by side, whereas Case 4 requires only an area large enough to hold two inductors side by side, and Case 1 requires only an area large enough to hold one and a half inductors side by side.

[0058] Case 1 offers the smallest core placement because it can fit two cores in the space of one. This is demonstrated by Figure 15, which shows that if each core is split in half and one half is placed on the top side and the other half on the bottom side, the board core area required is only half that of the cores in Case 0. This occurs because the core area in Case 1 is only half that of Case 0.

[0059] It is worth discussing the layouts of Cases 3 and 4 here. As mentioned above, Figure 5 shows an inductor arrangement with individual inductors plated on both sides of the carrier. It should be noted here that the inductor arrangement is identical, with each inductor winding connected to the other inductor winding by vias. Because the inductor windings that pass through the vias are a small fraction of the total windings, they have only a small, and not substantially significant, effect on the performance of the individual inductors. In the preferred embodiment, the number of windings that pass through the vias is less than three.

[0060] It's important to emphasize here that while windings through the core slightly degrade the inductor's performance, they connect the inductors together via the carrier, which allows for new inductor placement schemes and improves the inductors' ability to work together by eliminating the compensation mismatch problem.

[0061] As shown in FIG. 5, each of the inductors, inductor 501 and inductor 502, can have a core 510. The inductor core can be a nickel-iron material, an insulating layer formed by combustion chemical vapor deposition (SiO2), or any core material suitable for use as a core in the microelectronics field. As shown in FIG. 5, the case 2 inductors are ready for incorporation into an electrical system, such as a system-in-package. These inductors occupy significantly less horizontal space on a substrate than inductors plated in a single layer.

[0062] Although directly connected by windings, the inductors in Cases 3 and 4 can be considered as matched or coupled inductors. This distinguishes between two inductors and one large inductor. That is, in this example, one inductor can be used for the first phase of the DC-DC converter and the other inductor can be used for the second phase of the DC-DC converter.

[0063] A key advantage of these inductors is their ability to withstand damage from thermal expansion in all cases: because they are made of the same material, have the same shape, and are on the same carrier, they are matched with respect to thermal expansion and, as a result, have a matched response to expansion.

[0064] The ability to plate inductors on both sides of the carrier allows for unique inductor configurations with multiple inductors and multiple inductor pairs that allow the inductors being matched to be optimized to withstand environmental conditions without changing the compensation scheme, and even for multi-phase converters such as two-phase or three-phase converters.

[0065] As mentioned above, Figure 1 shows an inductor configuration for a two-phase converter. Here, inductor 101 is paired with inductor 103, and inductor 102 is paired with inductor 104. The winding of each inductor connects it to its corresponding inductor through one of the vias. This is an example of a case 4 inductor layout with two case 4 inductor pairs.

[0066] This is a prime example to demonstrate the ability of the common center of gravity approach to reduce errors due to compensation mismatch during manufacturing. As an example, FIG. 1 shows heat source 120 located closer to inductor 102 than the other inductors. This heat source may be present during plating in the plating bath during the manufacturing process and may cause slight differences in the plating rate of the material across regions in the bath. Given the location of heat source 120 and the matching arrangement of the inductors, inductor 103 will have the lowest temperature and inductor 102 will have the highest temperature during plating. However, inductor pair 101 and 103 and inductor pair 102 and 104 will have the same average temperature as each other because the average distance between each pair is the same.

[0067] The averaging effect is strongest when offset inductors are paired across the carrier. However, inductors may be paired with directly opposite inductors or with offset inductors, depending on the total number of inductors. Thus, in the multiple inductors shown in FIG. 16, each inductor may be paired with a directly opposite inductor, such as inductors 1601 and 1604, inductors 1602 and 1605, and inductors 1603 and 1606. These inductor pairs are arranged in part according to the common center of gravity principle, while still requiring a shorter carrier length than placing the same number of inductors on the same side of the carrier and maintaining the same inductor length between pairs. However, a more powerful common center of gravity-based approach could be the concatenation of inductors 1601, 1605, and 1603, and the concatenation of inductors 1604, 1602, and 1606.

[0068] If the inductors are placed according to a pure center of gravity approach, the average temperature experienced by the inductor pair will be the same. This is true even if the heat sources are not offset. However, certain inductors within a pair will expand at different rates. What is important here is that the average temperatures across the pair are matched.

[0069] FIG. 17 shows that heat source 120 is located above and centered between inductors 1701 and 1702. In this case, inductors 1701 and 1702 will have the same temperature. Meanwhile, inductors 1703 and 1704 will also have the same temperature, but at a different temperature than inductors 1701 and 1702. The placement of inductor pair 1701-1703 and inductor pair 1702-1704 results in the inductor pairs experiencing the same average temperature. This also means that thermal expansion is matched between the inductor pairs. However, to maintain the same temperature when heat sources are offset, the pairs must be spaced apart by a common center of gravity 160.

[0070] In this case, there are multiple factors in the system that affect the inductor's performance. However, the common center of gravity approach is still effective in minimizing compensation issues. Figure 18 shows a system influence element 1820 placed above the inductors (inductor 1801, inductor 1802, inductor 1803, inductor 1804) and a system influence element 1821 placed below the same inductors, with system influence element 1820 having a greater influence on the inductors than system influence element 1821. Although each system influence element has a different impact on the system, the inductors are still averaged across the elements and therefore matched without additional difficulty.

[0071] While environmental stressors are typically shown in the drawings as heat sources 120, inductors are likely to be exposed to many system influences at once, ranging from voltage to pH to temperature. For example, during plating, both the temperature of the plating bath and the voltage of the plating bath affect the deposition rate of the inductor material. Even after fabrication, inductors may be exposed to multiple heat sources and pressures.

[0072] While it is often best to maximize the common center of gravity approach, there are also cases where it is desirable to adopt the common center of gravity approach without necessarily optimizing. Inductors from all cases can be combined with each other to create various configurations. Not all embodiments need to be fully optimized or perfectly matched, yet still be manufacturable. For example, a substrate may be plated with a combination of cases and categories. For example, as shown in FIG. 19, the middle inductor (1901) from case 1 is combined with two inductor pairs (1901, 1904) and (1903, 1902) from case 3.

[0073] The drawings and figures depict multiple embodiments and are intended to illustrate specific embodiments, but are not limited to the scope, number, or aspects of the embodiments of the present invention. The present invention can incorporate countless aspects and specific embodiments. All figures are prototypes and schematic representations. The final product may be further improved by those skilled in the art. No element should be construed as critical or essential unless explicitly stated. Additionally, the articles "a" and "an" may be understood to mean "one or more," and when only one item is intended, the term "one" or other similar term is used. Additionally, terms such as "has," "have," and "having" are intended to be open-ended terms. The form of the inductor may differ from that shown in the drawings. Inductors constructed on the top or bottom surface of a core may be constructed in one or more layers above or below the top or bottom surface of the core.

Claims

1. 1. A method of manufacturing a matching inductor, comprising: Preparing the substrate; forming at least two through vias that extend from a first surface of the substrate to a second surface of the substrate opposite the first surface; plating an inductor coil over the length of the through via to enable electrical connection through the through via; plating a first inductor on a first surface of the substrate and a second inductor identical to the first inductor on a second surface of the substrate, the first inductor and the second inductor being electrically connected by an inductor coil passing through the through via; A method comprising:

2. The method of claim 1 , wherein the substrate is a printed circuit board.

3. The method of claim 1 , wherein the substrate is an Ajinomoto® build-up film.

4. The method of claim 1 , wherein at least one of the upper inductor and the lower inductor has a dedicated magnetic core.

5. The method of claim 1 , wherein at least one of the formed inductors is composed of a hybrid material.

6. The method of claim 1 , further comprising incorporating the plated inductor into a system as a coupled inductor.

7. The method of claim 1 , further comprising incorporating the plated inductor into a system as a matching inductor.

8. The method of claim 1 , wherein the number of windings of the inductor passing through the carrier is less than three.

9. Drilling at least two vias; plating an inductor coil through the via; and plating the first inductor and the second inductor to be matched to form at least one additional inductor pair on the same substrate; The method of claim 1 , further comprising repeating at least once.

10. The method of claim 9 , wherein each inductor pair comprises offset inductors.

11. The method of claim 10 , further comprising placing the inductors according to a common center of gravity approach.

12. a substrate having at least one through via extending from a first surface of a carrier to a second surface of the carrier opposite the first surface of the substrate; at least one upper inductor on a first surface of the substrate; at least one lower inductor on the second surface of the substrate; at least one of the upper inductors is operatively connected to the lower inductor by at least one coil of the upper inductor passing through at least one via forming an inductor pair; Inductor array.

13. The matching inductor of claim 13 , wherein at least one of the upper inductor and the lower inductor has a dedicated magnetic core.

14. The matched inductor of claim 12, wherein the magnetic core is a nickel-iron core.

15. The magnetic core is a hybrid SiO ２ The matching inductor of claim 12, which is a layered core.

16. The matching inductor of claim 12 , wherein the number of windings of the inductor passing through the carrier is less than three.

17. The matching inductor of claim 11 , further comprising at least one additional inductor, each of the additional inductors being disposed on the first surface of the substrate or the second surface of the substrate.

18. 16. The matching inductor of claim 15, wherein each inductor pair comprises offset inductors.

19. a substrate having at least one through via extending from a first surface of the substrate to a second surface of the substrate opposite the first surface of the substrate; a first portion of an inductor on a first surface of the substrate; a second portion of the inductor on a second surface of the substrate; a first portion of the inductor connected to a second portion of the inductor by at least one coil of the inductor passing through the at least one through via; Inductor array.

20. 20. The inductor arrangement of claim 19, wherein the substrate is a printed circuit board core material.

21. 20. The inductor arrangement of claim 19, wherein the number of turns of the inductor passing through the through via is less than three.

22. 20. The inductor arrangement of claim 19, wherein the inductors are arranged according to a common center of gravity approach.

23. further comprising at least one additional inductor; Each of the additional inductors has a first portion of the additional inductor disposed on the first surface of the substrate and a second portion of the additional inductor disposed on the second surface of the substrate; 20. The inductor arrangement of claim 19, wherein a first portion of the additional inductor is connected to the second portion of the additional inductor by at least one coil of the additional inductor passing through the at least one through via.

24. 30. The inductor arrangement of claim 29, wherein each of the first and second portions of the inductor are offset across the substrate.

25. 30. The inductor arrangement of claim 29, wherein there are at least two inductors arranged in a symmetrical arrangement.

26. 1. A method of manufacturing an inductor, comprising: Preparing the substrate; forming at least one through via extending from a first surface of the substrate to a second surface of the substrate opposite the first surface; plating an inductor coil over the length of the through via to enable electrical connection through the through via; plating a first portion of an inductor on a first surface of the substrate and a second portion of the inductor on a second surface of the substrate such that the first portion of the inductor and the second portion of the inductor are electrically connected by an inductor coil passing through the through via; A method comprising:

27. 27. The method of claim 26, wherein the substrate is a printed circuit board.

28. 27. The method of claim 26, wherein the substrate is an Ajinomoto® build-up film.

29. 27. The method of claim 26, wherein at least one of the formed inductors is composed of a hybrid material.

30. 27. The method of claim 26, further comprising incorporating the plated inductor into a system as a coupled inductor.

31. 27. The method of claim 26, further comprising incorporating the plated inductor into a system as a matching inductor.

32. 27. The method of claim 26, wherein the number of windings of the inductor passing through the carrier is less than three.

33. Drilling at least two vias; plating an inductor coil through said via; and then plating a first portion of at least one additional inductor onto the first surface of the carrier and a second portion of the additional inductor onto the second surface of the substrate, such that the first portion of the inductor and the second portion of the inductor are electrically connected by an inductor coil passing through the through via; 27. The method of claim 26, further comprising repeating at least one time.

34. 34. The method of claim 33, wherein each inductor pair comprises offset inductors.

35. 34. The method of claim 33, further comprising placing the inductors according to a common center of gravity approach.

Images