JP3575280B2 - Multilayer inductor - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an inductor used in a high-frequency circuit of a mobile communication device or the like, and more particularly to a multilayer inductor manufactured by screen printing in a process of laminating an electric insulating layer and a conductor pattern.
[0002]
[Prior art]
In recent years, with the trend toward smaller and thinner electronic components, various chip-type inductors have come to be used for inductor elements. Such an inductor element has attracted attention as a so-called laminated inductor in which a winding coil is formed by a conductor pattern in an electric insulating layer without using a winding as in the related art.
[0003]
As a method of forming the above-mentioned winding coil, a sheet laminating method in which ceramics are formed into a sheet shape, or a print laminating method in which all of the electric insulating layer and the internal conductor are formed by screen printing are known. Among the methods, especially the printing and laminating method has attracted attention because it is easy to automate and suitable for mass production, and various proposals have been made in terms of performance, reliability, price, and the like. For example, JP-B-60-50331, JP-A-4-111709, JP-A-5-24644, and JP-A-6-50312.
[0004]
Hereinafter, among the formation of the winding coil by the conventionally known printing lamination method, particularly typical ones will be described.
[0005]
For example, there is a method shown in FIG. 6 as one example. According to this drawing, first, in step (1), a dielectric ceramic pattern 1-21 is printed and laminated to a predetermined thickness, and an inverted L-shaped conductor pattern 2-21 is printed thereon, thereby forming a coil. Form a half turn. Next, a dielectric ceramic pattern 1-22 is printed on the lower half surface in step (2), and a new L-shape is formed so as to be connected to one end of the exposed conductor pattern 2-21 in step (3). Is printed to further form a half turn of the coil. Thereafter, the above steps are repeated to form a coil having a predetermined number of turns.
[0006]
Further, as another example, a method of printing a U-shaped pattern alternately as shown in FIG. 7 and printing and laminating each half turn, or as shown in FIG. Methods of printing and laminating every 3/4 turn are known, and all of these methods perform coil formation through the same steps as those in FIG.
[0007]
The start and end of the coil pattern thus formed are respectively drawn out to the outer end of the chip by a drawing pattern, and an external electrode (not shown) is connected to the exposed end. Here, the above-mentioned lead-out pattern for connection has, for example, a shape in which the ground plane with the external electrode is wide as shown in FIGS. 10 (a), 10 (b) and 10 (c).
[0008]
[Problems to be solved by the invention]
By the way, the following problems remain in the printing lamination method.
[0009]
The first point is a problem related to printing accuracy.
[0010]
For example, in the method according to FIG. 6, when the printing of each conductor pattern is shifted in the horizontal direction, as shown in FIG. 9 (3), the cross-sectional area of the orbital coil formed by the combination of L-shapes is reduced in the horizontal direction. However, there is a problem that the inductance value (L value) of the coil varies. Furthermore, there is a possibility that the displacement may occur in the vertical direction. In that case, as shown in FIG. 9 (5), the area surrounded by the coil pattern is further reduced, and the L value is reduced, which causes the L value to vary. In order to perform high-precision positioning without such printing deviation, it is necessary to stably control and maintain various printing elements such as a printing machine, a screen, and printing conditions, but this is an extremely difficult operation. It is. Moreover, such a printing shift often occurs in the 1/2 turn coil pattern not only in the method shown in FIG. 6 but also in the method shown in FIG. In particular, in the case of FIG. 8, the connection between the conductor patterns in the window portion is in the width direction of the coil, and thus the connection reliability is lacking.
[0011]
Further, in the method using the 1 / 2-turn U-shaped pattern shown in FIG. 7, when the chip is downsized and the vertical bar of the U-shape is shortened, sagging is likely to occur in the coil shape, and corners where printing accuracy is difficult to obtain are reduced. The proportion occupied by the copies increases, and high-precision printing cannot be performed.
[0012]
In addition, when the portion where the internal conductor is printed is below the previously printed insulating layer, the printed surface of the internal conductor becomes a valley bottom, especially when the chip is small and the area of the printed portion is small. The squeegee cannot operate efficiently because the upper insulating layer hinders the printing of the bottom of the valley, so that accurate printing cannot be performed.
[0013]
Further, in the method of FIG. 8, the window frame portion for connecting each conductor pattern moves on the coil pattern by 1/4 every printing, and becomes uneven due to the window frame portion, so that high-precision printing is difficult. become. In addition, when the inductor is small and the window frame portion is 0.15 mm × 0.15 mm or less, printing cannot be performed.
[0014]
The second point is a problem related to the Q value of the coil.
[0015]
Generally, in order to increase the Q value of a coil, it is necessary to form the inner conductor thicker and reduce the resistance of the conductor. To increase the thickness of the internal conductor, the same conductor pattern may be overprinted (painted twice), but this complicates the working process and increases the number of steps. Further, in the case of overprinting in the shape shown in FIG. 7, since the coil shape printed on the same surface is as small as 1/2, it is difficult to maintain a highly accurate coil shape.
[0016]
The third point is a problem related to the connection between the inner conductor and the outer electrode.
[0017]
In order to ensure the connection with the external electrode, the extraction pattern is shaped such that the area of the connection portion A with the external electrode is widened as shown in FIGS. 10 (a) to 10 (c). As shown in the figure, if the conductor pattern has a shape that intersects the connection portion A at a right angle, distortion tends to remain in the right angle portion, which may cause cracking. Further, as shown in FIGS. 10B and 10C, when the pattern of the connection portion A is brought closer to the coil side, the stray capacitance between the coil and the external electrode increases, the resonance frequency decreases, and the high-frequency characteristics deteriorate. I do.
[0018]
SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to provide a high-quality laminated inductor which realizes formation of a coil having high positional accuracy and a high Q value.
[0019]
[Means for Solving the Problems]
That is, according to the first aspect of the present invention, the electrical insulating layer (1) and the conductor pattern (2) are alternately printed and laminated, and the ends of each conductor pattern (2) are sequentially connected and overlap in the laminating direction. A coil inductor is formed, and the beginning and end of the coil pattern are connected to the external electrodes (3, 3) at the outer end of the chip in a lead pattern. A U-shaped pattern (2-2) serving as a connecting portion (a1), and an I-shaped pattern (2-3) disposed on the U-open side and having one end bent at a right angle to serve as a connecting portion (a2). Were alternately combined.
[0020]
As described above, when forming a one-turn coil, a coil shape is formed by combining a U-shape of 3/4 turn and an I-shape of 1/4 turn instead of combining a conventional 1 / 2-turn pattern. Even if the U-shaped pattern becomes smaller, it is easy to perform high-precision printing because the ratio of the corners where printing accuracy is difficult to obtain is small, and the rest is combined with an I-shape that is simple in shape and easy to print. Is higher than the combination of 1/2 turn patterns. Further, since the U-shaped pattern of 3/4 turns substantially determines the coil cross-sectional area, the variation of the cross-sectional area is reduced.
[0021]
According to the second aspect of the present invention, the conductor width of the I-shaped pattern (2-3) is formed larger in the outer direction of the coil pattern than the conductor width of the U-shaped pattern (2-2).
[0022]
This ensures the connection between the U-shaped pattern (2-2) and the I-shaped pattern (2-3). Further, by making the thickening direction outward, the coil cross-sectional area is not reduced.
[0023]
In the third aspect of the present invention, only the connection portion (a2) of the I-shaped pattern (2-3) is formed thicker in the outer direction of the coil pattern.
[0024]
This ensures connection between the U-shaped pattern (2-2) and the I-shaped pattern (2-3). Further, by making the thickening direction outward, the coil cross-sectional area is not reduced.
[0025]
According to the present invention, the composition of the printing conductor paste of the I-shaped pattern (2-3) and the composition of the printing conductor paste of the U-shaped pattern (2-2) are each formed in a pattern shape. It was different to match.
[0026]
That is, since the U-shaped paste uses a screen with a high number of meshes to obtain good printing accuracy due to its complicated shape, a paste suitable for the U-shaped paste and having a sharp particle size distribution of conductive particles is used. Is a paste with a slightly lower viscosity considering connectivity.
[0027]
Further, in the present invention described in claim 5, the sectional area of the coil pattern is made variable by moving the printing position of the I-shaped pattern (2-3) in the U-shaped direction, and the L value can be changed.
[0028]
Thus, the L value can be easily changed by moving the I-shaped pattern without producing a dedicated printing screen.
[0029]
Further, in the present invention described in claim 6, the conductor pattern (2) is configured to be printed on the upper side of the electrical insulating layer (1) printed immediately before except for the connection portion.
[0030]
For accurate printing, it is important that the printing surface is flat and that the printing surface is on the top layer. If the printing surface is in a valley, the squeegee pressure becomes uneven and printing with high accuracy cannot be performed. Therefore, high-precision printing is possible mainly by printing the conductor pattern on the uppermost surface. In other words, the connection portion becomes a valley bottom, but does not become a major factor in determining the coil shape, and the printing surface is important.
[0031]
According to the present invention, the electrical insulating layer (1) and the conductor pattern (2) are alternately printed and laminated, and the ends of the conductor patterns (2) are sequentially connected and overlap in the laminating direction. The coil pattern is formed, and the beginning and end of the coil pattern are connected to the external electrodes (3, 3) at the outer end of the chip in a lead pattern. A U-shaped part (2-12) and an I-shaped part (2-13) formed on the U-open side from one end of the U-shaped part (2-12). The conductor pattern (2) to be printed is not covered with the electric insulation layer (1) with the conductor pattern (2) previously printed, and the conductor pattern (2) is newly printed on the electric insulation layer (1). Conductor pattern (2) , And it constitutes almost one turn.
[0032]
As a result, the previously printed conductor portion is double-printed, and by repeating this, the conductor thickness is doubled and the Q value is improved by the usual number of times of printing. The difference from the double coating shown in FIG. 7 is that the combination of a large U-shape with high printing accuracy and an I-shape that is easy to print makes the coil accuracy higher than the conventional combination of small U-shapes even with two coatings. high. When the outer shape of the inductor is large, there is no problem with the conventional combination of small U-shapes, but there is a large difference in the case of a micro chip having a length and width of 1.0 mm × 0.5 mm or less.
[0033]
According to the present invention, the width of the conductor pattern passing through the stepped portions (a3, a4) generated by the overprinting is increased toward the outside of the coil pattern. This ensures connection of the step. Further, by making the thickening direction outward, the coil cross-sectional area is not reduced.
[0034]
According to the ninth aspect of the present invention, the conductor of the lead pattern is printed thicker than the coil pattern. Thereby, the resistance of the coil conductor is reduced.
[0035]
In the invention according to claim 10, the conductor width of the lead pattern is formed so as to gradually increase toward the outside of the coil pattern, and is connected to an external electrode. Thus, there is no crack, and connection to the external electrode can be made without increasing the stray capacitance at the connection between the coil and the external electrode of the lead conductor.
[0036]
In the present invention, a low-temperature sintered dielectric ceramic is used as a material of the electric insulating layer (1). Thus, a high Q value can be obtained even when used at a high frequency.
[0037]
According to the present invention described in claim 12, the U-shaped open portion of each conductor pattern (2) forming the coil pattern is printed and laminated in a direction perpendicular to the external electrode direction of the chip. did. Thereby, since the connection portions of the conductor patterns are arranged in the same manner on both external electrode sides, the structural balance of the chip is improved.
[0038]
Furthermore, in the present invention according to claim 13, the U-shaped open portion of each conductor pattern (2) forming the coil pattern is printed and laminated toward the external electrode (3, 3). . In this case, by increasing the length of the vertical bar in the U-shaped portion, the proportion occupied by the linear portion in one turn of the coil is increased, and a highly accurate coil pattern can be formed.
[0039]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a perspective view showing the appearance of the multilayer inductor. The laminated inductor is formed by alternately printing and laminating the electrical insulation layer 1 and the conductor pattern 2 to form a rectangular parallelepiped laminated chip, and sequentially connecting the ends of the laminated conductor patterns 2 to form the electrical insulation layer. The present invention comprises a circulating coil superimposed in the laminating direction within 1 and a leading end and an ending end of the circulating coil drawn out to both ends of a chip, and external electrodes 3 and 3 connected to these. Has a great feature in that the basic configuration is such that the winding coil is formed by a combination of a U-shaped pattern and an I-shaped pattern.
[0040]
In the laminated inductor of the present embodiment, for example, dielectric ceramics added with glass and sintered at a low temperature are used as the ceramic-based electric insulating material. Here, a dielectric material in which borosilicate glass is mixed with alumina in a ratio of 70:30 by volume is used, and a mixture of ethyl cellulose, a dispersant, and a plasticizer as a vehicle is mixed and mixed, and then mixed. Dielectric paste was prepared.
[0041]
In addition, silver was used as a conductor, and the vehicle was mixed with the silver to prepare a conductor paste. In addition, PVB, methylcellulose, or acrylic resin may be used other than ethylcellulose as a binder. Further, silver palladium may be used as the conductor paste.
[0042]
Next, a first embodiment of a method for forming a coil pattern will be described based on the process chart shown in FIG. This embodiment aims at forming a coil with high positional accuracy.
[0043]
First, in step (1), a dielectric pattern 1-1 made of a dielectric paste is repeatedly printed and laminated to form an electric insulating layer having a predetermined thickness. Is printed on the external electrode (not shown).
[0044]
Next, in step (2), a part of the conductor pattern 2-1 is left in an I shape, and the other part is covered with a dielectric pattern 1-2.
[0045]
Next, in step (3), a new U-shaped conductor pattern 2-2 is printed so as to be connected to the exposed end of the conductor pattern 2-1. In the present embodiment, the left end of the U-shaped pattern 2-2 is formed to be long to be the connection part a1. In the connection part a1, the ends of the conductor patterns 2-1 and 2-2 are orthogonal to each other, so that the connection can be reliably performed.
[0046]
Next, in step (4), the I-shaped portion of the conductor pattern 2-1 is covered with the dielectric pattern 1-3.
[0047]
Next, in step (5), a new I-shaped conductor pattern 2-3 is printed so as to be connected to the exposed end of the conductor pattern 2-2. In the present embodiment, the right end of the I-shaped pattern 2-3 is bent at a right angle to form a connection part a2. At this time, by making the I-shaped pattern wider than the U-shaped pattern, the reliability at the time of pattern connection in the steps (3) and (5) can be improved. Further, the width of the I-shaped pattern may not be widened over the whole but only the connecting portion a2. However, the direction in which the width is increased needs to be the outer direction of the coil pattern in any case. This is because, if the width of the coil pattern is uniformly increased toward the inside and the outside as in the related art, the coil cross-sectional area is reduced and the L value is reduced.
[0048]
Next, in step (6), the other portion is covered with a dielectric pattern 1-4 while leaving the conductor pattern 2-2 in an I-shape. Thereafter, the above steps (3) to (6) are repeated to form a coil having a predetermined number of turns.
[0049]
Next, in step (7), a conductor pattern 2-4 for drawing the terminal end of the coil to an external electrode (not shown) different from step (1) is printed.
[0050]
Finally, in step (8), a dielectric pattern is repeatedly printed and laminated until a predetermined thickness is obtained. In an actual process, the coil pattern is manufactured as a multi-piece laminated block in which the coil patterns are arranged and arranged.
[0051]
As described above, the laminated block produced through steps (1) to (8) is cut into chips, degreased, fired, and deburred, and external electrodes 3 and 3 are formed at both ends thereof. Baking and plating are performed to produce a multilayer inductor as shown in FIG.
[0052]
As described above, in the coil forming method according to the first embodiment of the present invention, since the coil pattern is configured by the combination of the U-shaped pattern 2-2 and the I-shaped pattern 2-3, the printing misalignment between the I-shaped and the U-shaped is performed. The resulting variation in the coil cross-sectional area can be made sufficiently smaller than the conventional combination of L-shape or U-shape, which is タ ー ン turn, because the U-shape that constitutes ／ of the coil determines the coil shape. Stable coil characteristics with little variation in L value can be obtained.
[0053]
Also, unlike a U-shape in which a one-turn coil is halved as in the conventional case, a U-shape formed by 3/4 turns of the coil has a small percentage of corners in the pattern where problems such as print sagging tend to occur. Small, high-precision printing becomes possible. Also, here, the high precision printing of the I-character is easy, and the point of the present invention is how the U-character can be printed with high accuracy. Enables production of coils.
[0054]
In addition, since the U-shaped pattern 2-2 and the I-shaped pattern 2-3 are printed separately, the composition (for example, viscosity) of the conductor paste is changed to optimize the composition suitable for each pattern shape. By printing with, printability can be further improved.
[0055]
For example, if the viscosity of the conductor paste of the U-shaped pattern is increased, high-precision printing can be performed, but the stability of the printed paste is reduced, so that it may be necessary to replace the paste on the way. At this time, only the U-shaped pattern paste needs to be replaced, and the I-shaped pattern paste does not require a paste having a high viscosity. If both are U-shaped, the paste for both patterns needs to be changed.
[0056]
Further, by shifting the printing position of the I-shaped pattern 2-3 in the U-shaped direction (vertical direction of the U-shaped), the cross-sectional area of the coil pattern using the same pattern can be arbitrarily and easily changed. Therefore, there is no need to create a new conductor pattern to change the L value.
[0057]
Also, as shown in the above steps, in the present embodiment, the conductor patterns are all printed on the electric insulating layer printed immediately before except for the connection parts a1 and a2, in other words, always printed on the uppermost surface. It has become. In this way, the conductor printing is always performed on the uppermost surface of the stepped surface, so that the squeegee can operate efficiently and the valley bottom printing has been forced even for small chips compared to the conventional method. And high-precision printing becomes possible.
[0058]
Furthermore, by connecting the connecting portions a1 and a2 of the conductor patterns forming the irregularities on the printing surface at two places at both ends of the I-shaped pattern 2-3, the U-shaped pattern 2-2 occupying 3/4 of the coil pattern is formed. It can be a flat surface without unevenness. This enables high-precision printing.
[0059]
As described above, in the formation of the coil pattern described above, the case where the open portion of the U-shaped pattern is printed and laminated in a wide shape in a direction perpendicular to the external electrode direction of the chip (the width direction of the chip) has been described. However, it is a matter of course that the open portion of the U-shaped pattern may be printed and laminated in a vertically long shape in the external electrodes 3 and 3 directions of the chip (the longitudinal direction of the chip).
[0060]
In this case, by increasing the length of the vertical bar in the U-shaped portion, the ratio of the area occupied by the linear portion in the U-shaped pattern in one turn of the coil is increased as compared with the former, and the printability is good even with a small chip. A highly accurate coil pattern can be formed. However, in the case of this configuration, since the connection portions a1 and a2 of the conductor pattern 2 are biased toward the external electrode 3 on one side, the structural balance is not good. Therefore, the former configuration is easy to stabilize the characteristics because of its good structural balance, and the latter is excellent in forming a coil having a small cross-sectional area because of its good printing accuracy. Therefore, a formation method can be selected according to desired characteristics. FIG. 3 shows a method in the latter case, but the printing process is the same as in the case of FIG. 2 described above, and a description thereof will be omitted here.
[0061]
Next, a second embodiment of the coil pattern forming method will be described based on the process chart shown in FIG. In the present embodiment, a coil having a high Q value is realized by coating the inner conductor twice.
[0062]
First, in step (1), a dielectric pattern 1-11 is repeatedly printed and laminated until a predetermined thickness is reached, and a conductive pattern 2-11 (to be connected to an external electrode (not shown)) connected to an external electrode (not shown) is formed thereon. Printout pattern). Here, the width of the lead conductor portion (a portion that is not applied twice, which will be described later) is increased in the outer direction of the coil pattern, or another internal conductor portion is formed by using a conductor paste of another composition that makes the printing thicker. Form thicker.
[0063]
Next, in step (2), the other portion is covered with a dielectric pattern 1-12 while leaving the conductor pattern 2-11 in an I-shape.
[0064]
Next, in step (3), a new conductor pattern is printed so as to overlap the exposed I-shaped portion of the conductor pattern 2-11. At this time, the vicinity of the step portion a3 generated by the dielectric pattern 1-12 is painted once, so that the step width can be surely printed by forming the conductor width wider in the outer direction of the coil pattern. The conductor resistance of the portion can be reduced.
[0065]
Meanwhile, the conductor pattern has a rectangular shape including a U-shaped portion 2-12 and an I-shaped portion 2-13, and is formed by a combination of the I-shaped pattern and the U-shaped pattern described in the first embodiment. Is basically the same as
[0066]
Next, in step (4), the I-shaped portion 2-13 is covered with the dielectric pattern 1-13.
[0067]
Next, in step (5), a rectangular conductor pattern is printed so as to overlap the exposed U-shaped portion 2-12. In this manner, by simultaneously printing the exposed portion of the conductor pattern that has been printed first, the conductor portion can be made thicker without increasing the number of steps. At this time, similarly to the above, the conductor width of the step portion a4 is formed wider in the outer direction of the coil pattern.
[0068]
Next, in step (6), the other portion is covered with a dielectric pattern 1-14 except for the I-shaped portion 2-13. Thereafter, the above steps (3) to (6) are repeated to form a coil having a predetermined number of turns.
[0069]
Next, in a step (7), a conductor pattern 2-14 (a terminal of the coil terminal) connected to another external electrode (not shown) different from the step (1) so as to overlap the I-shaped portion 2-13. Printout pattern). Here, similarly to the process (1), the conductor width of the portion of the conductor pattern 2-14 that is not coated twice is increased in the outward direction, or the conductor is printed thicker by changing the conductor paste.
[0070]
Finally, in step (8), the dielectric pattern 11-5 is repeatedly printed and laminated to a predetermined thickness. The produced laminated block is cut into chips, and external electrodes 3 and 3 are formed on both ends thereof, thereby producing a laminated inductor as shown in FIG. This process is the same as in the first embodiment described above.
[0071]
As described above, in the coil forming method according to the second embodiment of the present invention, the internal conductor is overprinted to reduce the conductor resistance and improve the Q value of the inductor. In this embodiment, the shape of the overprinting is divided into a U-shape and an I-shape, and the U-shape portion occupying 3/4 of the rectangular coil pattern is printed on the same surface, so that the pattern at the time of printing is obtained. Improving accuracy. In other words, the printing surface of the I-shaped pattern having a simple shape may be small, but the U-shaped pattern is secured by securing a large printing surface, so that the pattern including the corners is overprinted by タ ー ン turn. By providing a wide print surface that is easy to print in a U-shape that divides the I-shape and the U-shape that controls the coil cross-sectional area, it is possible to form a pattern with high accuracy in both single-layer printing and overlapping printing. Moreover, as described above, the first time of the overlap printing for determining the accuracy of the coil is always the uppermost surface of the insulating layer, so that the stability of the coil shape is excellent.
[0072]
As described above, in the formation of the coil pattern described in the second embodiment, the case where the open portion of the U-shaped pattern is printed and laminated in a direction perpendicular to the external electrodes of the chip (the width direction of the chip) has been described. The present invention is not limited to this. Of course, the open portion of the U-shaped pattern may be printed and laminated in the direction of the external electrodes of the chip (the longitudinal direction of the chip). FIG. 5 shows a coil forming method in this case. The printing process is the same as that of FIG.
[0073]
Next, the connection between the conductor pattern and the external electrode will be described.
[0074]
In the conventional example of FIG. 10 described above, the grounding portion A with the external electrode has a right-angled shape. On the other hand, in the present invention, the first embodiment shown in FIG. As shown in (1) and (7) of FIG. 4 in the embodiment, the width of the conductor pattern drawn to the external electrode side (not shown) gradually increases in the outer direction of the coil at the ground portions A1 and A2. It is formed as follows.
[0075]
By gradually increasing the conductor width of the ground portions A1 and A2, stress applied to the corners is reduced and cracks and the like hardly occur, so that the reliability of connection with the external electrodes is extremely high. Further, by forming the wide portion only in the outer direction of the coil, the stray capacitance can be reduced as much as possible.
[0076]
【The invention's effect】
As described above, according to the first aspect of the present invention, the coil pattern is formed by the combination of the U-shaped pattern and the I-shaped pattern. Compared with the conventional L-shape or 1 / 2-turn U-shape combination, the coil size can be made sufficiently small, so that stable coil characteristics with little variation in L value can be obtained.
[0077]
According to the second or third aspect of the present invention, since the conductor width of the I-shaped pattern is formed larger in the outer direction of the coil pattern than the conductor width of the U-shaped pattern, the connection between the I-shaped pattern and the U-shaped pattern is achieved. Is assured, and the reliability is improved. Moreover, since the coil cross-sectional area is not reduced by expanding the coil pattern outward, the L value does not decrease. Further, the pattern width may be extended only to the connection portion.
[0078]
Further, according to the present invention, the composition of the conductive paste can be changed according to the pattern shape between the I-shaped pattern and the U-shaped pattern, and the printability is improved. No high-precision printing can be performed and the coil shape is stable.
[0079]
According to the present invention, the printing position of the I-shaped pattern is moved in the U-shaped direction so that the cross-sectional area of the coil pattern can be changed and the L value can be changed. An arbitrary L value can be easily realized without any problem.
[0080]
Further, in the present invention as set forth in claim 6, since the conductor pattern is configured to be printed on the upper side of the electrical insulating layer printed immediately before except for the connection portion, it is possible to perform valley bottom printing in the conventional method. In printing, the squeegee can operate efficiently without being disturbed by the already printed insulating layer, and high-precision printing can be performed.
[0081]
In the present invention according to claim 7, the coil pattern is formed by printing a conductor pattern formed by a U-shaped portion and an I-shaped portion on the exposed U-shaped portion or the I-shaped portion. Therefore, the previous print pattern is sequentially superimposed and printed simultaneously with the printing of a new conductor pattern, so that the man-hour increase due to the superimposed printing does not occur. Moreover, in this case, since the U-shaped portion occupying 3/4 of the conductor pattern is printed on the same surface, the position accuracy of the overprinting is extremely good.
[0082]
Further, in the present invention according to claim 8, the width of the conductor pattern passing through the step portion generated by the overprinting is increased toward the outside of the coil pattern, so that the step portion can be reliably printed, and The conductor resistance of the portion can be reduced. In addition, since the pattern width is expanded in the outer direction of the coil pattern, the coil cross-sectional area is not reduced.
[0083]
Further, according to the present invention as set forth in claim 9, in the overprinting, the conductor thickness of the lead pattern is printed thicker than the coil pattern. Q value can be increased.
[0084]
According to the tenth aspect of the present invention, since the conductor width of the lead pattern is formed so as to gradually increase in the outward direction of the coil pattern, the stress applied to the corner of the ground portion is relaxed, and cracks and the like hardly occur. Therefore, the reliability of the connection with the external electrode becomes extremely high. Further, by forming the wide portion only in the outer direction of the coil, the stray capacitance between the internal coil and the internal coil can be minimized.
[0085]
Further, in the present invention described in claim 11, since the low-temperature sintered dielectric ceramics is used as the electric insulating layer, the stray capacitance between lines can be reduced, and the use in a high frequency band is possible. Further, since low-temperature firing is possible, the production of a multilayer inductor is facilitated.
[0086]
Further, in the present invention as set forth in claim 12, since the U-shaped open portion of each conductor pattern forming the coil pattern is printed and laminated so as to face in a direction perpendicular to the external electrode of the chip, the connection portion of the conductor pattern is formed. Are similarly arranged on both external electrode sides, so that the structural balance is good and the characteristics are stable.
[0087]
Further, according to the present invention, since the U-shaped open portions of the conductor patterns forming the coil patterns are printed and laminated so as to face the external electrodes, the length of the U-shaped coil is increased. Since the ratio occupied by the straight portion in the turn increases and the print sag at the corner can be reduced, the printability is good even with a small chip, and a highly accurate coil pattern can be formed. Therefore, it is particularly effective for a chip having a tight L value tolerance.
[Brief description of the drawings]
FIG. 1 is an external perspective view of a multilayer inductor.
FIG. 2 is a process chart showing a method for forming a coil of a multilayer inductor according to a first embodiment of the present invention.
FIG. 3 is a process chart showing a coil forming method of a laminated inductor different from that of FIG. 2;
FIG. 4 is a process chart showing a method for forming a coil of a multilayer inductor according to a second embodiment of the present invention.
5 is a process chart showing a method of forming a coil of a laminated inductor, which is different from FIG.
FIG. 6 is a process chart showing a conventional method for forming a coil of a laminated inductor.
FIG. 7 is a process chart showing a coil forming method of a laminated inductor different from that of FIG. 6;
FIG. 8 is a process chart showing a coil forming method of the laminated inductor different from that of FIG. 7;
FIG. 9 is a plan view showing a printing displacement of a coil pattern.
FIG. 10 is a plan view showing a conductor pattern drawn to an external electrode.
[Explanation of symbols]
1 Electrical insulation layer
2 Conductor pattern
2-2 U-shaped pattern
2-3 I-shaped pattern
2-12 U-shaped part
2-13 I-shaped part
3 External electrodes
a1, a2 connection part
a3, a4 Stepped part

Claims (13)

The electrical insulating layer (1) and the conductor pattern (2) are alternately printed and laminated, and the ends of each conductor pattern (2) are sequentially connected to form a coil pattern superimposed in the laminating direction. Wherein the start end and the end of are connected to the external electrodes (3, 3) at the outer end of the chip in a lead pattern,
The coil pattern is a U-shaped pattern (2-2) having one end elongated and having a connection portion (a1), and a U-shaped open side, and one end is bent at a right angle to form a connection portion (a2). A laminated inductor comprising an I-shaped pattern (2-3) alternately combined. 2. The multilayer inductor according to claim 1, wherein the conductor width of the I-shaped pattern (2-3) is formed to be larger in the outer direction of the coil pattern than the conductor width of the U-shaped pattern (2-2). 3. . 2. The multilayer inductor according to claim 1, wherein only the connection part (a2) of the I-shaped pattern (2-3) is formed to be thicker in the outer direction of the coil pattern. The composition of the conductor paste for printing of the I-shaped pattern (2-3) and the composition of the conductor paste for printing of the U-shaped pattern (2-2) are different depending on the pattern shape. The multilayer inductor according to any one of claims 1 to 3. 3. The L-value can be changed by moving the printing position of the I-shaped pattern (2-3) in the U-shaped direction to change the area surrounded by the coil pattern. 5. The multilayer inductor according to any one of 4 to 4. The conductor pattern (2) is printed on the upper side of the electrical insulating layer (1) printed immediately before, except for the connection portion, according to any one of claims 1 to 5. The multilayer inductor according to any one of the preceding claims. The electrical insulating layer (1) and the conductor pattern (2) are alternately printed and laminated, and the ends of each conductor pattern (2) are sequentially connected to form a coil pattern superimposed in the laminating direction. Wherein the start end and the end of are connected to the external electrodes (3, 3) at the outer end of the chip in a lead pattern,
The conductor pattern (2) includes a U-shaped portion (2-12) and an I-shaped portion (2-13) formed on the U-shaped open side from one end of the U-shaped portion (2-12). Consisting of
The coil pattern includes a conductor pattern (2) that is not covered by the electric insulation layer (1) with the conductor pattern (2) that is printed at the same time. 3.) A multilayer inductor comprising a conductor pattern (2) newly printed thereon and constituting substantially one turn. The multilayer inductor according to claim 7, wherein the width of the conductor pattern passing through the stepped portions (a3, a4) generated by the overlap printing is increased toward the outside of the coil pattern. 9. The multilayer inductor according to claim 7, wherein a conductor thickness of the lead pattern is printed so as to be thicker than the coil pattern. 10. As the conductor width of the lead pattern approaches the external electrode (3, 3), it is formed so as to gradually increase in the outer direction of the coil pattern and is connected to the external electrode (3, 3). The multilayer inductor according to any one of claims 1 to 9, wherein: The multilayer inductor according to any one of claims 1 to 10, wherein a material of the electric insulating layer (1) is a low-temperature sintered dielectric ceramic. The U-shaped open portion of each conductor pattern (2) forming the coil pattern is printed and laminated so as to face in a direction perpendicular to the direction of the external electrodes of the chip. The multilayer inductor according to any one of the above. 12. The printed circuit according to claim 1, wherein a U-shaped open portion of each conductor pattern (2) forming the coil pattern is printed and laminated so as to face an external electrode (3, 3). The multilayer inductor according to any one of the above.

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