TW200847885A - Printed circuit board and its manufacturing method - Google Patents

Abstract

The present invention provides a printed circuit board, in which coil devices with high inductance is formed in the printed circuit board so as to greatly reduce the component carrying area and thus achieve small size and high density for the printed circuit board, and a method for manufacturing the printed circuit board with low cost and high stability. In the printed circuit board and its manufacturing method, the printed circuit board is formed in more than two layers and has coils with inductance. The printed circuit board is characterized in that: the coil has a spiral wiring pattern (7), and a conductive magnetic body part (30) arranged in the center of the wiring pattern and electrically connected to the wiring pattern, where the conductive magnetic body part is employed to achieve inter-layer electrical connection.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board and a method of manufacturing the same, and more particularly to a printed circuit board having a coil having an inductance formed therein and a method of manufacturing the same. [Prior Art] In recent years, it has been demanded to reduce the mounting area of circuit components based on the demand for miniaturization and high density of printed circuit boards. The number of circuit components mounted on a printed circuit board has been increasing year by year, and the mounting area of these circuit components poses a great obstacle to the miniaturization of printed circuit boards. The circuit components mounted on the printed circuit board include a semiconductor integrated circuit such as ic or LSI, a chip capacitor or a chip coil provided in the circuit, and a chip resistor. Taking a conventional chip capacitor as an example, even the smallest component has a size of 0.6 mm x 0.3 mm, considering the printing size of the solder paste used for mounting, the size of the contact for mounting the part, and the mounting for the adjacent component. The pattern gap of the electrical insulation of the contacts, etc., the mounting area of each of the above elements becomes 0.6 mm x 0.3 mm. Even if the size of the circuit element alone is reduced, there is a limit to the accuracy of forming the solder resist layer on the surface of the printed circuit board and the formation of the circuit pattern, etc., so that the mounting area of the circuit element is further reduced. There will be difficulties. In addition, small circuit components have to be specified for the functions to be obtained. For example, if a larger inductance is required, a larger chip coil is necessary. Based on this, it is preferable to build a driven component such as a coil on a printed circuit board, and to reduce the mounting area of the circuit component. -4- 200847885 Figure 3 (1) shows an example of a circuit diagram of a portion for supplying power to a semiconductor circuit mounted on a conventional printed circuit board. In the case where the coil element of the inductor is used for sealing the power supply layer, the high-frequency noise layer emitted from the semiconductor integrated circuit is prevented from being efficiently branched to the ground (GND) layer. Such a printed circuit board is usually carried out by the following steps. First, as shown in Fig. 4 (1), it is prepared to have thickness wiring patterns 72 and 73 on both sides of the polyimide edge substrate 71. The bottomed vias 74, 75 filled with the charge plating are laminated to the printed circuit board 71. Next, as shown in Fig. 4 (2), a single-sided laminate 79 of a copper foil 78 having a thickness of 18 μm on one side of a material 77 of polyimide or the like is interposed, and an interlayer adhesive sheet 80 having a thickness of 80 μm is interposed. And laminated on both sides of the double-sided printed circuit board 76 by a stamper or the like. Next, as shown in Fig. 4 (3), the copper foil 78 surface of the conformal mask single-sided copper foil laminate 79 at the time of laser processing is used in a normal photosensitive etching method, and the copper foil is used. A single-sided copper box laminate of a conformal mask is processed to form a conductive hole having a diameter of 100 to 15 Ομηη. Then, after the desmear treatment and the electroconductive treatment, electrolytic plating is performed, and interlayer conduction is obtained by the electric holes 81, 82, and 83 as a pretreatment for obtaining interlayer connection by electricity. Next, as shown in Fig. 4 (4), the copper foil 7 8 of the surface layer is plated with copper, and a wiring circuit is formed by a usual photosensitive etching process [volume; example ‘. This. Power "乍. ^的绝$导孔^的两U彖基3Foil product 真空Vacuum] The workman 丨成在^有正一激光进行进行导化3 Electroplating and electric 78a, -5- 200847885 7 8 b, and the formation of solder Photoresist layer 84. For the terminal surface of the contact portion or connector for component mounting, surface treatment such as tin plating, nickel plating, or gold plating is applied as needed. At this time, the bottomed via 74 of the inner layer and the via 81 connected to the bottom via 74 serve as a power supply layer, and the bottom via 75 of the inner layer and the conductive via connected to the bottom via 75 are connected. Hole 82 acts as a power plane as a ground (GN D ) layer. At this time, the wiring circuit 718 has the following wiring pattern. Figure 4 (5) is a commemorative plan view of the wiring circuit 7.8 a, which corresponds to the 4th (4) diagram. The wiring circuit 7 8 a is formed with the component mounting contacts 9 1 to 9 6 , and the soldering-to-part mounting contacts 9 1 and 9 2 are mounted with the chip coils 9 7 to solder the component mounting contacts 9 3 , 9 . 4 Install the chip capacitor. Further, the semiconductor integrated circuit 9 9 is mounted on the component mounting contacts 95 and 96 to form a circuit as shown in Fig. 3 (1). As a result, the mounting area of the circuit element such as a chip capacitor or a chip coil is increased for each power supply terminal. As a result, in addition to the difficulty in miniaturization of the printed circuit board, the periphery of the semiconductor integrated circuit The layout of the wiring is also complicated, and even the loop that causes the complicated wiring itself to occupy the area on the printed circuit board. For this point, the method of forming the driven element of the coil into the inside of the printed circuit board includes a method of using a meandering or spiral wiring pattern (Japanese Patent Document 1). Then, by forming such a wiring pattern, an inductance can be added to the circuit. However, the inductance obtained by this wiring pattern is only slightly different, but -6 - 200847885 but occupying a large area on the printed circuit board does not conform to miniaturization and high density. In addition, a method of forming a wiring pattern of a larger inductance in a printed circuit board is disclosed, and Japanese Patent Document 2 discloses that a spiral wiring pattern is formed across the layers of the multilayer printed circuit board at the center. A method of forming a perforation or a magnetic body electrically separated from a spiral wiring pattern. However, these methods still occupy a large area for each coil element built in, which does not conform to miniaturization and high density, and cannot solve the problem. [Patent Document 1] Japanese Patent Laid-Open Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. The obstacle caused by the miniaturization and high density of the printed circuit board is the mounting area of the circuit component. Even if the circuit component is miniaturized, the precision of the solder resist layer on the surface of the printed circuit board is mounted by soldering, and the circuit is formed. There are limits to the formation of patterns, etc., and it is still difficult to further reduce the mounting area of circuit elements. In addition, the small-sized chip coil must have a larger inductance for the limited inductance to be obtained, and a larger chip coil is necessary. Based on this, it is preferable to build a driven component such as a coil on a printed circuit board to reduce the mounting area of the component. The present invention has been made in view of the above problems, and an object thereof is to provide a printed circuit board having a sufficiently inductive coil element formed inside a printed circuit board to substantially reduce the mounting area of the device and having a small and high density. And a method of manufacturing the printed circuit board inexpensively and stably. <Means for Solving the Problem> In order to achieve the above object, the present invention provides the following first and second inventions. According to a first aspect of the invention, there is provided a printed circuit board having two or more layers of a coil having an inductance, wherein the coil includes a spiral wiring pattern; and is disposed at a center of the wiring pattern and the wiring The conductive magnetic body portion electrically connected to the pattern; and the electrical connection between the layers is performed by the conductive magnetic body portion. According to a second aspect of the invention, there is provided a method of manufacturing a printed circuit board having a coil having an inductance, comprising: forming a spiral wiring pattern and a contact portion electrically connected to a center of the wiring pattern; And a step of forming a hole for forming a conductive magnetic body portion electrically connected to the contact portion; and forming a conductive magnetic body portion electrically connected to the contact portion in the hole step. [Effect of the Invention] According to the present invention, it is provided that a coil element having a surface area of -8-200847885 and having a diameter of only 550 μm is formed inside the printed circuit board, and the component mounting area is greatly reduced. Multi-layer printed circuit board with reduced density and miniaturization. Further, it is possible to inexpensively and stably manufacture a multilayer printed circuit board which can be both high-density and miniaturized. [Embodiment] Hereinafter, embodiments of the present invention will be described with reference to the drawings. <Example 1 >

Figs. 1(1) to 1(4) are explanatory views showing the basic structure of the planar coil and its electromagnetic action. Among them, the first (1) diagram is a view of a planar coil in which a wiring pattern is formed in a spiral shape. When the current I flows in the coil, the spiral current forms a magnetic field, and the magnetic flux Φ proportional to the current I penetrates the center of the coil. When the magnetic flux φ time of the coil changes, as the time changes, a reverse electromotive force ν is generated in the spiral wiring pattern in proportion to the number of turns of the coil (the following expression 1)

V Ν ά Φ The hit Φ is proportional to the current I. Therefore, the proportional constant L is added to the above equation 1 to become the following expression 2. -9 - 200847885 This proportionality constant L is called the self-inductance of the coil (hereinafter referred to as the inductance), and for the alternating current, it acts like a resistor proportional to the frequency ω. It is generally known that in the case where a magnetic core is formed in the center, a large magnetic flux Φ is obtained for the same current I, so that the inductance of the coil can be increased. In the case of calculating the inductance of the planar coil having the spiral wiring pattern, it is preferable to approximate the spiral wiring pattern by a plurality of circumferential wiring patterns. When the current I flows through the circumference of the radius R, the current I causes the intensity of the magnetic field generated near the center to be expressed by the following formula 3, and when the center area of the coil is S and the permeability of the vacuum is μϋ, The magnetic flux Φ penetrating the center of the coil is expressed by the following formula 4. Equation 3 - Η

Equation 4 Φ

_ S//〇I R )---Γ"

2R When the spiral wiring pattern is formed as a number of turns, the radius Rk of the k-th circular current can be expressed by the radius R 中心 of the coil center and the wiring pitch: P, so the magnetic flux penetrating the center of the coil is It is expressed by the sum of the magnetic fluxes formed by other circular currents (Expression 5 below). Τ N-1 1 Equation 5...〇>an= However, the radius of the kth circular current is: 2 k=o Rk

Rk 二 R〇+ kP -10 - 200847885 Based on the sum of the magnetic fluxes and the inductance L of the above-described equation 1, the N-number coil, the calculation is performed as in the following equation 6. Equation 6 L = NS//0 £4 1

- 2 SR 〇 + kP Here, the design 値 (Expression 7) of the first embodiment is substituted into the above Equation 6, and a specific inductance is calculated to obtain 2 5 · 7 ( η Η ). N=1 1 (times) Ρ = 3 0(μηΐ) Equation 7 — S=kR20 μ〇= 4πχ 1〇"7 (η.γ -1 η ) R〇=l 80(μηι) 1 ( 2 The figure is a view of a case where a magnetic body is formed at the center of the spiral wiring pattern. The magnetic flux density inside the magnetic body is the intensity of the 磁场-based magnetic field, and the magnetic permeability of the magnetic body is μ, which is expressed by the following formula 9. When the radius of formation of the magnetic body is RB, the circular current I of the radius R penetrates the magnetic flux at the center of the coil. Φ is represented by the following formula 10. Equation 9 — B = μ . μ 〇Η Equation 10 --- ®(R) ==μ〇Η(κ)(πΚ 〇+ μπΚ β) =Chu (πΐ^ + μπ!^) Use this formula In the case where the magnetic body -11 - 200847885 is formed at the center of the above-mentioned number of coils, the inductance is calculated by the following formula 11. In the first embodiment, a nickel body is used as the magnetic body, and the specific permeability is μ and 600. If the coil design is substituted (the following formula 1 2), the inductance of the coil is calculated as 1 2 1 7 ( η Η ). N = =1 1 (times) Ρ = 3 0 (μΐΏ) Equation 12 - R 〇: =1 8 0 ( μηι ) μ〇 = 4π X 1 0'7(Hr -1 η ) Rb 1 = 5 0 ( Μπι ) μ « 6 0 0 In general, the inductance of the chip coil used in the printed circuit board is considered to be 1 to 3 0 0 (η Η ). The design of this degree (the size of the coil) is practically compatible. It is not necessary to increase the size of the magnetic body in vain, or to form a spiral wiring pattern across the layers of the multilayer printed circuit board. Thus, by forming a magnetic body in the center of the spiral wiring pattern, the inductance of the coil can be greatly increased. Further, in the present invention, electrical connection between the layers is also performed by using a conductive material for the magnetic body. Therefore, it is not necessary to separately provide an interlayer connection element to be additionally provided, and the occupied area of the coil component required for ensuring the practically necessary inductance can be greatly reduced. 2A, 2 is a diagram showing the printed circuit of the present invention. A section view of the process of the board. This printed circuit board is produced through the following steps. That is, -12- 200847885 is 'first prepared two-sided copper box laminate 4, which is composed of epoxy, polyimide, etc. as shown in Figure 2A (1) Both sides of the insulating base material 1 having a thickness of about 50 μm have copper foils 2 and 3 having a thickness of 6 μm. The insulating base material 1 is not limited to the material of epoxy or polyimide, and can be used separately depending on the application. For example, it is necessary to reduce the dielectric loss during high-speed signal transmission, and a two-sided copper foil laminate using a liquid crystal polymer or the like as a low-dissipation factor material can also be used. In addition, the double-sided copper foil laminate 4 is a substrate corresponding to the inner core of the multilayer printed circuit board, secondly, as shown in the second figure (2), for the double-sided copper foil laminate 4, with UV-YAG A direct laser processing method such as laser is used to form a conductive hole having a diameter of about 50 to 100 μm, and then a conductive process and a via hole charge plating are performed to form the interlayer connection portion 5, and electrical connection between the layers is performed. The laser processing is not limited to the direct laser processing method, and may be replaced by a conformal laser processing method or the like. In the plating treatment, one side is subjected to a mask treatment, or only one side is energized, so that the copper foil on one side of the double-sided copper foil laminate 4 (here, the two sides) is electroless. This is helpful when the subsequent coil formation 'forms a fine spiral wiring pattern. Further, the interlayer connection portion 5 is not limited to the bottomed via hole filled by the via hole charge plating, and the bottom via hole formed by the usual electrolytic plating or the connection of a general via hole may be used. The double-sided copper foil laminate 6 to which the layers are connected is obtained through the following steps'. -13- 200847885 Next, as shown in Fig. 2A (3), the wirings 2a, 3a are formed by a usual photosensitive etching process. Fig. 2A (4) is a plan view of the wiring pattern 2a formed on the copper foil 2 side of the double-sided copper foil laminate 6, and the A-A' cross section corresponds to the 2A (3) diagram. In order to add an inductance to the circuit, it is preferable to form such a spiral wiring pattern 7. At the center of the spiral wiring pattern 7, a contact 8 having a diameter of about 300 μm, which is used for interlayer connection, is provided. The inductance attached to the circuit is qualitatively proportional to the second power of the number of turns of the spiral wiring pattern 7. In order to obtain a large inductance, it is preferable to increase the number of turns. In order to reduce the mounting area of the surface layer of the printed circuit board, such a spiral wiring pattern is preferably formed on the inner electrode layer of the multilayer printed circuit board, and an electroless plating method can be formed by increasing the number of turns. Construction is more advantageous. In the first embodiment, since the interlayer connection portion 5 is a via hole for charge plating of the via hole, it is not necessary to consider the hiding property of the dry film photoresist, and a high resolution film dry film photoresist can be used, and copper is used. Since the foil 2 side is electrolessly plated, it is combined with a thickness of 6 μm to form a fine wiring having a pitch of 30 μm. In this way, a spiral wiring pattern 7 having a diameter of 690 μm was formed as the number of turns 1 = 1 1 . In this way, the area occupied by the coils on the layer of the wiring pattern 2a is a very small diameter of 1 〇 〇 〇 μιη or less. Further, the wiring pattern 3a facing the spiral wiring pattern 7 may be removed by etching, and the pattern of the portion 3b facing the contact 8 may be removed. In this case, the layer winding of the wiring pattern 3a The area occupied by -14-200847885 is an area with a diameter of only 300 μm. The two-sided printed circuit board 9 having the wiring pattern is obtained through the following steps. Next, the interlayer adhesive sheet 2 1 and the single-sided copper foil laminate 22 are laminated on both surfaces of the double-sided printed board 9 on which the wiring pattern is formed as shown in the second drawing (A), and heated and pressurized. The double-sided copper foil laminate 9 single-sided copper foil laminate 22 is bonded together. At this time, since the wiring pattern is not formed on the one-sided copper laminate 22, it is not necessary to perform the alignment of the laminate. As the interlayer adhesive sheet 2 1 , for example, an adhesive sheet of a material such as acryl or epoxy having a thickness of 80 μm can be used. The one-sided copper foil laminate 2 2 can be used for one of the insulating bases 23 having a thickness of about 50 Å, such as epoxy or polyimide, and has a laminate of copper foil 24 having a thickness of 18 μm. Further, the insulating base material 23 is not limited to epoxy or polyimine, and may be used separately depending on the use. For example, a copper foil laminate having a liquid polymer or the like as a base material can also be used as a material having a low dissipating factor. Further, in the case where the flexible cable portion is simultaneously produced, the flexible polyimide film may be sandwiched between the surface copper foil laminate 9 and the single-sided copper foil by the adhesive sheet 2 1 . Between the plates 22, the necessary portions of the respective base materials are subjected to external shape processing, and the alignment is performed to laminate the layers, and a double-sided copper foil laminate may be used instead of the single-sided copper foil laminates 2 2 . In this case, it is necessary to form a wiring pattern in advance on the surface of the double-sided copper box laminate to which the adhesive is applied. The multi-wiring substrate 25 is obtained through the above steps. Next, as shown in the second A (6) diagram, the copper foil 24 of the multilayer wiring substrate 25 is formed into a crystal for the positive electrode and the foil acid material by a usual photosensitive etching method. Laminated layer -15- 200847885 Conformal laser processing of a conformal mask, followed by carbon dioxide gas laser processing of the orthodontic mask to form a general diameter of 10 0~15 Ομηη Hole 26. Further, by the drilling process, the conventional perforation 27 having a diameter of about 100 μm is formed in a portion corresponding to the contact 8 of the inner layer. The through hole 27 is a conductive magnetic body portion which is filled with nickel or the like, and which has an inductance added to the circuit and is used to obtain a common hole for electrical connection between the layers. The hole for charging such a conductive magnetic body portion is intended to increase the inductance of the coil element. Therefore, it is preferable to form three or more holes extending across the multilayer printed circuit board. Further, such a hole is advantageous in that the volume of the conductive magnetic body portion which is filled later is formed by forming a hole from the surface more than the hole formed only in the inner layer. In addition, the above-mentioned series of hole formation is not limited to drilling processing, and the required productivity and processing accuracy are measured, and the quality 'can be used for carbon gas laser processing or UV-YAG laser processing alone or in combination. . The multilayer wiring substrate 28 on which the conductive holes are formed is obtained through the above steps'. Next, the multi-layer wiring substrate 28' having the conductive holes formed as shown in Fig. 2(7) is subjected to desmear treatment for removing the glue 'slag generated by the laser treatment' and then conducting After the treatment, 'dry film resist 29 is laminated on both sides of the substrate, followed by exposure and development, so that the through-hole 2 is masked by dry film photoresist (dr > film resist 29) Part other than 7. -16- 200847885 At this time, the deviation of the exposure position is measured. With respect to the through hole 2 of the diameter of 100 μm, the opening of the dry film photoresist 2 is set to a diameter of 250 μm (allowing one side of 75 μm) Deviation). If this degree of deviation can be tolerated, the use of a general-purpose exposure machine can be fully matched, and it is not necessary to use an expensive high-precision exposure machine. In this way, the area occupied by the coil on the surface of the printed circuit board is a very small diameter of 25 Ομηη, and even if the gap with the adjacent pattern is measured, the occupied area is still only about 305 μm in diameter. In addition, the image processing is performed by combining the image processing position, the direct scanning exposure apparatus, and the direct exposure, and the precision is technically suppressed to the extent that one side is 1 〇 μηη, and the adjacent pattern gap is further narrowed. The occupied area of the coil can be suppressed to be less than 2 μμη in diameter, and then the nickel body belonging to the conductive magnetic body portion of 30 μη is precipitated by electrolytic nickel plating, and the through hole 27 is filled with the nickel body 30. internal. In this case, in addition to supplying power from the copper foil 24, "the power is supplied from the inner layer wiring pattern 2a, and the nickel plating is first deposited in the inner layer portion of the through hole 27", and the pinhole or the like can be stably filled. The inside of the hole 27. Further, in addition to the nickel body, other materials such as cobalt or these alloys may be used separately from the material of the conductive magnetic body portion. Next, as shown in Fig. 2B (8), the "release dry film photoresist 2" is re-conducted if necessary, and then electrolytic copper plating of 丨5~2 Ομη is performed to form via holes 3. 1. At this time, in the case where the nickel body 3G is directly above the -17-200847885 and assembled over other parts, there is a problem that the nickel body 30 is a problem. In this case, after the dry film resist 29 is peeled off, the honing treatment or the like is performed separately to ensure the flatness of the printed circuit board. The treatment is preferably carried out by using a chemical etching solution which is very low in uranium to copper and selectively oxidizing the nickel, for example, an etching solution containing hydrogen peroxide or nitric acid, by which only nickel is selectively used. The protrusion of the body 30 is removed. Next, as shown in Fig. 2B(9), etching is performed by a normal photosensitive smear method to form wiring patterns 2 4 a and 2 4 b, and then a tin photoresist layer 32. In the etching, it is preferable to use an etching liquid which selectively etches copper for the corrosiveness of copper, for example, which contains a urethane basicity, by which a copper contact 2 4 c can be formed on the nickel body 3 . 0 At this time, the coil formed inside the printed circuit board, only the portion of g occupies the surface layer of the printed circuit board, even if it is measured and adjacent to the gap, the occupied area is still only about 305 μm in diameter. In addition, in the above etching step, an uranium engraving solution using a copper engraving step, for example, an etching solution containing copper chloride (Π), etc., is required to expand the copper contact 2 4 c to cover the entire surface of the nickel body 30. The large size so that the nickel body 30 will not be removed. To realize a circuit like the one shown in Fig. 3 (1), for example, the wiring is electrically changed to the following shape. Hereinafter, a pattern in which the wiring pattern 2a 3 0 of the inner layer is connected is used as a power source layer, and a pattern in which the interlayer connection portion vias 31 of the inner layer are connected is used as a ground (D) layer. The protrusion is further honed to etch CMP (can be processed to form a low soldering, selective etching solution. The use of the collective 30 case, must be small 24a and the body 5 and -18 - 200847885 2B (1〇) is a view of the wiring circuit 24a. The cross section B' section corresponds to the 2nd B (9) diagram. In the wiring pattern 2 4 a, the mounting contacts 51 to 54 are formed. And 54, an integrated circuit 5 5 of 1C or the like is mounted, and an electric external portion for driving the semiconductor integrated circuit 5 5 is supplied to the component mounting contact 5; [and 52, the solder mounting device 56 is mounted. The capacitor 56 has the meaning of diverging the high-frequency noise emitted from the semiconductor body to the GND, and suppressing the drop caused by the switching operation of the power source voltage volume body circuit 55. Further, the mounting contact 51 is via The nickel body 30 is connected to the power supply layer 2a through the spiral pattern 7 of the inner layer, whereby the circuit configuration shown in the figure is realized. Through the above steps, a coil component having a surface layer diameter of only 305 μm is formed on a printed circuit board, and a printed circuit board can be manufactured at a low cost and stably, and can be miniaturized. . The inductance of the portion of the built-in coil printed circuit board produced in this manner was measured to confirm the effect. In the case where nickel is formed in the core portion of the spiral wiring pattern and when it is connected by ordinary electrolytic copper plating, the results of the measurement of the sample of η == 50 are not shown in (2). Further, the measurement voltage was 5 (ν)' measurement frequency (kHz). As shown in the third figure (3), it is judged that the spiral wiring pattern is formed, and the B-forming component is semiconductor force. Another capacitor S-way 5 5 is accompanied by half, the wiring of the part is straight inside, and the middle perforation of the high-density line is connected to the center of the 100th to the center of -19-200847885

When the Cu is perforated and connected, the inductance of the coil is 20 to 5 〇 (η Η ) degree. However, when the nickel body belonging to the conductive magnetic body portion is connected, the inductance is increased to the range of 200 to 500 (η Η ). This increase width is smaller than the magnitude of the increase estimated by the above equation 6 and the above formula 11, and the inductance can be increased by at least three times or more even in consideration of the deviation. In the calculation of the above formula 1 1 , the influence of the height of the magnetic body is ignored, and the following discussion takes this into consideration. Then, returning to Fig. 1, the first (3) diagram shows the intensity Η of the magnetic field formed when the current I flows through the circumference of the radius R, and how it is dependent on the Ζ axis passing through the center of the circle vertically. Mindfulness map. The strength Η of the magnetic field on the center axis of the center can be calculated by the following formula 13.

This equation indicates that Ζ = 0 becomes the dependence of the largest mountain shape, and the maximum 値 is 1, and the Z/R (the ratio Ζ of the height Ζ to the coil radius R) is plotted as in the first (4) diagram. The effect of forming a magnetic body having a finite height is considered to be proportional to the strength Η of the magnetic field of the portion where the magnetic body is formed. Therefore, it is necessary to obtain the area of the portion where the magnetic body is formed in the first (4) diagram. The above expression 13 is converted into Z / tan 0 by a variable, and can be integrated by the following equation 14. -20- 200847885 Equation 1 4 £ H(R Z)dz =

By this, the finite height h _ the expression 15 is formed to perform the calculation range). In the case of a magnetic body having an infinite height, the influence ratio with respect to the case of the magnetic body may be as follows (the magnetic body is formed at -h/2 <Z<h/2

In the above equation 10, the influence ratio is substituted into the above equation 10, and the magnetic current Φ at the center of the line R of the radius R of the radius R when the magnetic body having a finite height is formed is obtained as the following expression 16.

Formula 16 Φ

ΑοΙ 2R 1 +

2 RIT In the case where the magnetic body of a finite height is formed at the center of the N-number coil as described above, the inductance is calculated by the following formula 17 -21 - 200847885

LN / / 〇 gk = 0 1 - JR2 i 1 R 〇 + kP 〇 2 L 1 UJ 丄 The height of the magnetic body in the first embodiment is about 400 μm, so the design of these coils is substituted (the following formula 18) The inductance of the coil is calculated to be 70 8 ( η Η ). N = :1 1 (times) P = 30Um) h = 400iμm) Equation 12 - Rc 1 = 1 8 0 ( μ m ) μ〇 = 4πχ lO^cH.m"1) Rb =5 0 ( μ m ) μ ; « 600 Thus, in the case of forming a magnetic body having a finite height, the obtained inductance is reduced even after calculation, and the measurement result of the embodiment 1 is satisfied. Calculating the difference between the enthalpy and the measured enthalpy due to the approximation for other parts, or the deviation of the above design 値 step, the permeability of the nickel body formed by electrolytic plating, the frequency dependence, etc. There is a difference in this absolute savings. BRIEF DESCRIPTION OF THE DRAWINGS The first (1) to the first (1) figure is a conceptual view of the plane coil formed by the spiral wiring pattern and the Ζ direction dependence of the magnetic field 。. Section 2 (1) to 2 (6) is a cross-sectional view and a plan view of the structure of the printed circuit board of the present invention -22-200847885 and the manufacturing method. 2B(7) to 2B(10) are schematic cross-sectional views and plan views showing the construction and manufacturing method of the printed circuit board of the present invention. 3(1) and 3(2) are circuit diagrams showing an example of a circuit for supplying power to a semiconductor integrated circuit, and characteristic diagrams showing measurement data obtained by an embodiment of the present invention. 4(1) to 4(5) are schematic cross-sectional views and plan views showing the structure and manufacturing method of a conventional multilayer printed circuit board. [Main component symbol description] 1 : Insulation substrate 2 having a thickness of about 50 μm: Copper foil 2a having a thickness of about 6 μm: Wiring pattern 3: Copper foil having a thickness of about 6 μm 3 a : Wiring pattern 3 b : Wiring to the contact Pattern removing portion 4: double-sided copper-clad laminate 5 = interlayer connection portion 6: double-sided copper foil laminate 7 to which interlayer connection is applied: spiral wiring pattern 8: contact 9: double-sided printed circuit board 2 on which wiring patterns are formed 1 : interlayer adhesive sheet 22 : single-sided copper foil laminate • 23- 200847885 2 3 : insulating substrate 24 having a thickness of 50 μm: copper foil 24a, 24b having a thickness of about 8 μm: wiring circuit 2 4 c : Copper contact 2 5 : multilayer wiring substrate 26 : conductive hole 2 7 : through hole 2 8 : multilayer wiring substrate 29 with conductive holes formed: dry film resist 3 0 : nickel body 3 1 : via hole 3 2 : solder resist layer 5 1 to 54 : part mounting contact 5 5 : semiconductor integrated circuit 5 6 : chip capacitor 7 1: insulating substrate 72, 73 : wiring pattern 74, 75 : bottomed via 7 7 : insulating substrate 78 : copper foil with thickness 18 μm 79 : single-sided copper foil laminate

80: interlayer adhesive sheet 81, 82, 83: conduction 孑 L 8 4 : solder resist layer - 24 - 200847885 9 1 to 96 : contact for mounting parts 9 8 : chip capacitor 99 : semiconductor integrated circuit - 25-

Claims (1)

200847885 X. Patent Application No. 1 A printed circuit board in which two or more layers of a coil having an inductance are formed, wherein the coil includes: a spiral wiring pattern; and is disposed in the wiring The center of the pattern is a conductive magnetic body portion electrically connected to the wiring pattern, and the interlayer electrical connection is performed by the conductive magnetic body portion. 2. The printed circuit board of claim 1, wherein the wiring pattern is formed in an inner layer of three or more layers of the printed circuit board. 3. The printed circuit board according to claim 1 Wherein the conductive magnetic body portion is formed over at least three layers of a surface layer including a multilayer printed wiring board. 4. A method of manufacturing a printed circuit board, which is a method of manufacturing a printed circuit board having a coil having an inductance, comprising the steps of: electrically connecting a spiral wiring pattern and a center of the wiring pattern; a step of forming a dot portion; a step of forming a hole for forming a conductive magnetic body portion electrically connected to the contact portion; and forming a conductive magnetic body portion electrically connected to the contact portion The steps in the hole. 5. The method of manufacturing a printed circuit board according to claim 4, wherein the step of forming the conductive magnetic body portion is subjected to electrolytic nickel plating to cross the surface layer including the multilayer printed circuit board. At least three or more layers of the nickel body are formed inside the pores, and the nickel body is used to electrically connect the layers. 6. The method of manufacturing a printed circuit board according to claim 4, wherein the step of forming the conductive magnetic body portion is performed by electrolytic nickel plating to form a nickel body inside the hole, The spiral wiring pattern formed in the inner layer electrode layer is supplied with power. -27-