JP2005236158A - Laminated coil component, method for manufacturing the same, and structure for mounting the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small laminated coil component which can be easily mounted on a circuit board and be easily connected thereto by wire bonding. <P>SOLUTION: The laminated coil component includes a ceramic element body 3 of a nearly rectangular shape having a coil conductor 4 built therein and made of laminated ceramic green sheets, and upper and lower surface electrodes 6 and 8 formed on the upper and lower surface of the ceramic element body 3 and electrically connected to the coil conductor 4. The thickness T of the element body is smaller than the length L and the width W thereof. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a multilayer coil component, a method of manufacturing a multilayer coil component, and a mounting structure of the multilayer coil component, and more specifically, a chip-type multilayer such as a multilayer inductor or multilayer impedance in which external electrodes are formed on the surface of a ceramic body. The present invention relates to a coil component, a manufacturing method of the multilayer coil component, and a mounting structure of the multilayer coil component.

  Conventionally, the integration of chip-type electronic components and ceramic multilayer boards and other bonding-type electronic components mounted on a wiring pattern formed on an insulating substrate and wire bonding connection between the bonding-type electronic components and the chip-type electronic components. A circuit manufacturing method is known (Patent Document 1).

  In Patent Document 1, as shown in FIG. 10, a chip-type electronic component 104 is mounted on a wiring pattern 102 formed on an insulating substrate 101 via a solder 103, and one external electrode of the chip-type electronic component 104 is mounted. A side surface 105 a of 105 and an electrode 108 of a bonding-type electronic component 107 are bonded to each other with a wire 109.

JP-A-9-36515

  However, in the conventional chip-type electronic component 104 as disclosed in Patent Document 1, since the external electrodes 105 and 106 are usually applied and formed by the dipping method, the side surface 105a and the end surface 105b of the external electrode 105 are rough and smooth. It is difficult to form a surface, and as a result, there is a problem that even if the wire 109 is bonded and connected as shown in FIG. In particular, in the small chip-type electronic component 104 (for example, length L 1.0 mm, width W 0.5 mm, thickness 0.5 mm or less), the area of the side surface 105a is small, and the area of the smooth portion is also small. Therefore, there is a problem that it is difficult to perform a stable bonding connection.

  Further, when external electrodes 105 and 106 are mounted on the wiring pattern 102 of the circuit board 101 with solder 103 as in Patent Document 1, and the side surface portion 105a of one external electrode 105 is bonded and connected with a wire 109, ordinary solder is used. Since self-alignment is not performed as in the case of mounting, it is necessary to mount with higher positional accuracy. For this purpose, it is considered preferable to mount the chip-type electronic component 104 in an upright state.

  However, as shown in FIG. 12, the conventional chip-type electronic component 104 usually has a length L larger than the thickness T in dimension, so that the chip-type electronic component 104 is made upright on the wiring pattern 102 of the circuit board 101. When trying to mount in this way, the chip-type electronic component 104 is mounted in a tilted state or is likely to fall down, so that it is not easy to perform desired mounting on the circuit board. In addition, in this case as well, there is a problem that it is difficult to firmly connect the wire 109 because the area of the smooth portion of the external electrode 105 is small.

  The present invention has been made in view of such circumstances, and can be easily mounted on a circuit board even if it is small in size, and can be easily bonded by wire bonding, and the product yield. It is an object of the present invention to provide a method for manufacturing a laminated coil component that can be improved, and a mounting structure for the laminated coil component.

  In order to achieve the above object, a laminated coil component according to the present invention is formed on a surface of a substantially rectangular parallelepiped ceramic body in which a coil conductor is built and ceramic green sheets are laminated, and the surface of the ceramic body. In addition, in the laminated coil component comprising the external electrode electrically connected to the coil conductor, the external electrode is formed on the upper surface electrode in the laminating direction of the ceramic green sheet and on the lower surface in the laminating direction. The bottom surface electrode is formed, and the dimension in the laminating direction is smaller than the dimension in two directions orthogonal to the laminating direction.

  In the multilayer coil component of the present invention, the upper surface electrode and the lower surface electrode are formed in different shapes.

  The laminated coil component of the present invention is characterized in that the upper surface electrode and the coil conductor are electrically connected in the vicinity of a peripheral edge portion of the upper surface electrode.

  The multilayer coil component of the present invention is characterized in that at least the upper surface electrode of the upper surface electrode and the lower surface electrode constituting the external electrode is formed of a conductive sheet.

  Further, in the method for manufacturing a laminated coil component according to the present invention, the ceramic green sheets having a coil pattern formed on the surface are laminated so that the dimension in the laminating direction is smaller than the dimension in two directions orthogonal to the laminating direction, A laminate forming step for forming a substantially rectangular parallelepiped laminate, a ceramic element forming step for forming a ceramic element by subjecting the laminate to a firing process, and an upper surface of the ceramic element using a conductive paste And an upper surface electrode forming step of forming a lower surface electrode by subjecting the ceramic body to a dipping process.

  Further, in the method for manufacturing a laminated coil component according to the present invention, the ceramic green sheets having a coil pattern formed on the surface are laminated so that the dimension in the laminating direction is smaller than the dimension in two directions orthogonal to the laminating direction, Furthermore, a laminated body forming step of forming a substantially rectangular parallelepiped laminated body by laminating ceramic green sheets whose upper surface electrodes are previously formed by a printing process, and a ceramic element for forming a ceramic body by subjecting the laminated body to a firing process And a lower surface electrode forming step of forming a lower surface electrode by subjecting the ceramic body to dipping.

  Furthermore, in the method for manufacturing a laminated coil component according to the present invention, the ceramic green sheets having a coil pattern formed on the surface are laminated so that the dimension in the lamination direction is smaller than the dimension in two directions perpendicular to the lamination direction, Furthermore, a laminate forming step of forming a substantially rectangular parallelepiped laminate by laminating ceramic green sheets whose upper surface electrodes are previously formed by a printing process, and performing a printing process on the lower surface of the laminate using a conductive paste. It includes a lower surface electrode forming step for forming a lower surface electrode, and a ceramic body forming step for forming a ceramic body by subjecting the laminate on which the upper surface electrode and the lower surface electrode are formed to a firing process.

  Further, in the method for manufacturing a laminated coil component according to the present invention, the ceramic green sheets having a coil pattern formed on the surface are laminated so that the dimension in the lamination direction is smaller than the dimension in two directions orthogonal to the lamination direction, A laminate forming step of forming a substantially rectangular parallelepiped laminate, an electrode forming step of forming a top electrode and a bottom electrode by performing a printing process on the top and bottom surfaces of the laminate using a conductive paste, and the top electrode and And a ceramic body forming step of forming a ceramic body by subjecting the laminated body on which the lower surface electrode is formed to a firing process.

  The multilayer coil component mounting structure according to the present invention is a multilayer coil component mounting structure using the multilayer coil component, and the lower surface electrode of the multilayer coil component is electrically connected to the circuit board. And mounted on the circuit board, and the upper surface electrode of the multilayer coil component is connectable to a bonding wire.

  According to the laminated coil component described above, the external electrode electrically connected to the coil conductor includes an upper surface electrode formed on the upper surface in the laminating direction of the ceramic green sheet and a lower surface electrode formed on the lower surface in the laminating direction. In addition, since the dimension in the stacking direction is formed to be smaller than the dimension in two directions orthogonal to the stacking direction, the lower surface electrode is stably mounted on the circuit board without being inclined or overturned. In addition, even when the upper surface electrode is wire-bonded, the plane portion of the upper surface electrode is wide, and therefore, the wire can be bonded and connected stably and firmly.

  In addition, since the laminated coil component of the present invention is formed in a shape different from that of the upper surface electrode and the lower surface electrode, the upper surface electrode and the lower surface electrode can be easily identified, and the mounting operation is facilitated. Can do.

  In addition, while wire bonding is usually performed by setting a target at the center of the upper surface electrode, there is a surface where bonding connection is difficult at the connection portion between the coil conductor and the upper surface electrode. Is electrically connected in the vicinity of the peripheral edge of the upper surface electrode, so that the connection portion between the coil conductor and the upper surface electrode and the connection portion between the upper surface electrode and the wire can be avoided and bonding connection can be avoided. It can be easily performed.

  In the multilayer coil component of the present invention, at least the upper surface electrode of the upper surface electrode and the lower surface electrode constituting the external electrode is formed of a conductive sheet, so that the upper surface electrode has excellent smoothness. Therefore, it is possible to easily obtain a laminated coil component capable of bonding connection with high bonding strength.

  Further, in the method for manufacturing a laminated coil component according to the present invention, the ceramic green sheets having a coil pattern formed on the surface are laminated so that the dimension in the laminating direction is smaller than the dimension in two directions orthogonal to the laminating direction, A laminate forming step for forming a substantially rectangular parallelepiped laminate, a ceramic element forming step for forming a ceramic element by subjecting the laminate to a firing process, and an upper surface of the ceramic element using a conductive paste The upper surface electrode is formed by the printing process since the upper surface electrode forming process for forming the upper surface electrode by performing a printing process and the lower surface electrode forming process for performing the dipping process on the ceramic body to form the lower surface electrode is included. Therefore, it is possible to perform wire bonding even on a smooth top electrode, and a laminated coil capable of bonding connection with high bonding strength. It can be easily manufactured parts.

  Also, instead of forming the upper surface electrode by printing on the upper surface of the ceramic body, a ceramic green sheet having a coil pattern formed on the surface is laminated, and the ceramic on which the upper surface electrode has been previously formed by the printing process. Even if green sheets are laminated to form a substantially rectangular parallelepiped laminate, wire bonding can be performed on a smooth upper electrode, and a laminated coil component capable of bonding connection with high bonding strength can be obtained. It can be manufactured easily.

  The method for manufacturing a laminated coil component according to the present invention comprises laminating ceramic green sheets having a coil pattern formed on the surface so that the dimension in the laminating direction is smaller than the dimension in two directions perpendicular to the laminating direction, A laminate forming step of forming a substantially rectangular parallelepiped laminate by laminating ceramic green sheets on which an upper surface electrode is formed by a printing process, and a lower surface electrode by performing a printing process on the lower surface of the laminate using a conductive paste And forming a ceramic body by subjecting the laminate on which the upper surface electrode and the lower surface electrode are formed to a ceramic body, so that the upper surface electrode and the lower surface electrode are formed. Both are formed by printing, so wire bonding can be performed on the smooth top electrode, and bonding with high bonding strength is possible. Can be manufactured easily, and the bottom electrode is printed before firing, so there is no need to perform dipping after firing, and productivity can be improved. Become.

  The multilayer coil component mounting structure according to the present invention is a multilayer coil component mounting structure using the multilayer coil component, and the lower surface electrode of the multilayer coil component is electrically connected to the circuit board. Since the upper surface electrode of the multilayer coil component is connected to the bonding wire, the multilayer coil component can be mounted on the circuit substrate without being inclined or overturned. By performing wire bonding mounting on the upper surface electrode having a wide plane area, it is possible to realize a highly reliable mounting structure capable of bonding mounting having strong bonding strength.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view showing an embodiment of a multilayer inductor as a multilayer coil component according to the present invention. The multilayer inductor 1 is mounted on a circuit board 2.

  The multilayer inductor 1 includes a ferrite element body 3 (ceramic element body) formed in a substantially rectangular parallelepiped shape, a coil conductor 4 incorporated in a coil shape in the thickness direction of the ferrite element body 3, and an upper surface of the ferrite element body 3. And a lower electrode 8 formed on the lower surface of the ferrite element body 3 and electrically connected to the wiring pattern 7 on the circuit board 2. The upper electrode 6 and the lower electrode 8 constitute an external electrode.

  The ferrite body 3 is formed by subjecting a laminated body of magnetic sheets (ceramic green sheets) to a firing process. The laminated inductor 1 has a thickness T, which is a dimension in the laminating direction of the magnetic sheets, It is formed to be smaller than the dimensions in two directions orthogonal to the stacking direction, that is, the length L and the width W.

  Thus, since the thickness T is formed so as to be smaller than the length L and the width W, the position of the center of gravity is close to the lower surface, and the multilayer inductor 1 can be stably placed. Therefore, even when the small multilayer inductor 1 is mounted on the circuit board 2, the lower surface electrode 8 can be easily mounted on the wiring pattern 7 without being inclined or falling down. Further, since the upper surface electrode 6 is formed on the upper surface of the substantially rectangular parallelepiped ferrite element body 3, the planar portion of the upper surface electrode 6 is wide and a sufficient planar area can be secured, and the wire 5 is strong and stable. Bonding connection is possible.

  Next, a method for manufacturing the multilayer inductor will be described in detail.

First, as a ceramic raw material, a predetermined amount of ferrite raw material such as Fe ₂ O ₃ , NiO, CuO, ZnO is weighed, the ferrite raw material is put into a ball mill together with water, sufficiently mixed by diffusion, and then dried. A ferrite raw material is prepared. Next, the ferrite raw material is calcined at a predetermined temperature for a predetermined time to cause a solid-phase reaction to obtain a calcined product. Next, this calcined product is thrown into a ball mill together with water and pulverized, sufficiently stirred to make a slurry, and then dried to obtain a ferrite powder.

  Next, a ferrite resin and a binder resin such as polyvinyl butyral resin and an organic solvent such as ethanol and toluene are added and kneaded to prepare a ferrite slurry, and then subjected to a molding process using a doctor blade method or the like to obtain a predetermined film thickness ( For example, a magnetic sheet of 50 μm) is produced.

  Next, as shown in FIG. 2, magnetic sheets 9a to 9j prepared as described above are prepared. Then, using a laser processing machine, via holes 10a and 10j for drawing out coil conductors are formed in the central portions of the magnetic sheets 9a and 9j, and the magnetic sheets 9b to 9i have positions corresponding to one end portions of the coil patterns. Via holes 10b to 10i are drilled.

  Next, a conductive paste mainly composed of a conductive material such as Ag is used, and approximately U-shaped (3/4 turn) coil patterns 11c to 11h are formed on the magnetic sheets 9c to 9h by screen printing. Form. Further, the connection patterns 11b and 11i are formed on the magnetic sheets 9b and 9i by screen printing so that the coil patterns 11c and 11h can be electrically connected to the via holes 10a and 10j. The conductive paste is filled.

  Next, the magnetic sheets 9a to 9j are laminated and pressed and pressure bonded to produce a laminated body.

  Next, the laminate is cut into predetermined dimensions such that the thickness T is smaller than the length L and the width W, and then heated in the atmosphere, for example, at a temperature of 500 ° C. to burn and remove the binder resin. A firing process is performed at a temperature of 900 ° C. for a predetermined time, thereby producing a ceramic sintered body.

  Next, this ceramic sintered body is subjected to barrel polishing to obtain a ferrite element body 3 with a corner portion having an R shape, and then screen printing is performed on the upper surface of the ferrite element body 3 so as to cover the via hole 10a. A printed coating film having a predetermined shape is formed, and further, a conductive paste is applied to the entire lower surface area of the ferrite element body 3 by a dipping method. Thereafter, a firing process is performed at a predetermined temperature (for example, 850 ° C.). An electrode 8, that is, an external electrode is formed, whereby the multilayer inductor 1 is manufactured.

  Since the multilayer inductor 1 formed in this way has a thickness T smaller than the length L and the width W, the lower surface electrode 8 can be easily placed on the wiring board 7 on the circuit board 1 via a solder material or a conductive adhesive. Since the upper surface electrode 6 is formed by printing, the upper surface electrode 6 has excellent smoothness suitable for wire bonding mounting, and wire bonding with good bonding strength is possible. A laminated coil component can be obtained.

  In the above embodiment, the upper surface electrode 6 is formed by screen printing on the upper surface of the ferrite body 3. However, the upper surface electrode is formed by performing screen printing on the magnetic material sheet 9 a in advance. Each of the magnetic sheets 9a to 9j including the magnetic sheet on which the electrodes are formed is laminated, and thereafter, a laminated body is produced by pressing and pressure bonding, and a fired treatment is performed on the laminated body to obtain a ceramic sintered body. It may be.

  Moreover, it is also preferable to form a plating film of Ni, Sn, Au or the like on the surfaces of the upper surface electrode 6 and the lower surface electrode 8 by using an electrolytic plating method or an electroless plating method as necessary.

  FIG. 3 is a cross-sectional view schematically showing a second embodiment of a multilayer inductor as a multilayer coil component. In the second embodiment, the ferrite element body 13 in which the coil conductor 12 is incorporated is shown. An upper surface electrode 14 and a lower surface electrode 15 formed of a conductive sheet made of silver, a silver alloy, gold, or the like are provided on the upper surface and the lower surface, and the thickness T is smaller than the length L and the width W.

  The multilayer inductor according to the second embodiment is manufactured as follows.

  That is, as shown in FIG. 4, magnetic sheets 16a to 16i manufactured by the same method as in the first embodiment are prepared.

  Then, using a laser processing machine, via holes 17a and 17i for extracting coil conductors are formed in predetermined positions of the magnetic sheets 16a and 16i, and the magnetic sheets 16b to 16h are provided at one end of the coil pattern. Via holes 17b to 17i are formed at corresponding positions.

  Next, a conductive paste mainly composed of a conductive material such as Ag is used, and substantially L-shaped (1/2 turns) coil patterns 18b to 18h are formed on the magnetic sheets 16b to 16h by screen printing. The via holes 17a and 17i are filled with the conductive paste.

  Next, the conductive sheet 20 is placed on the film that has been subjected to the release treatment, and the magnetic sheets 16a to 16i and the conductive sheet 19 are sequentially laminated and pressure-bonded on the conductive sheet 20, and then the film Is peeled off to obtain a laminate.

  Next, the laminate is cut into predetermined dimensions such that the thickness T is smaller than the length L and the width W, and then heated in the atmosphere, for example, at a temperature of 500 ° C. to burn and remove the binder resin. A firing process is performed at a temperature of 900 ° C. for a predetermined time to manufacture the multilayer inductor according to the second embodiment.

  Also in the second embodiment, as in the first embodiment, since the thickness T is formed to be smaller than the length L and the width W, the position of the center of gravity is close to the lower surface, and the multilayer inductor is It can be allowed to stand stably. Therefore, even when a small multilayer inductor is mounted on a circuit board, the lower surface electrode 15 can be easily mounted on the wiring pattern of the circuit board without tilting or overturning. Further, since the upper surface electrode 14 made of a conductive sheet is formed on the upper surface of the substantially rectangular parallelepiped ferrite element body 13, the upper surface electrode 14 has good smoothness, and on the upper surface electrode 14 having such good smoothness. Since wire bonding can be performed, bonding connection with excellent bonding strength is possible.

  Moreover, in the second embodiment, the via hole 17a is formed not on the central portion but on the peripheral portion of the magnetic sheet 16a, which is convenient for wire bonding mounting. That is, although it is considered that bonding connection is difficult at the connection portion of the upper surface electrode 14 and the coil conductor 12, in the second embodiment, the coil conductor 12 and the upper surface electrode 14 are electrically connected to each other at the peripheral portion of the upper surface electrode 14. Therefore, the bonding connection can be easily performed.

  Further, as the third embodiment of the present invention, it is preferable that both the upper surface electrode and the lower surface electrode of the multilayer inductor are formed by screen printing.

  FIG. 5 is an exploded perspective view showing the layer structure of the magnetic sheet according to the third embodiment.

  Hereinafter, the manufacturing method of the third embodiment will be described in detail.

  First, magnetic sheets 21a to 21g manufactured by the same method as in the first embodiment are prepared.

  And using a laser processing machine, a via hole is drilled in the predetermined position of the magnetic material sheets 21a-21g.

  Next, a conductive paste mainly composed of a conductive material such as Ag is used, and screen printing is performed on the upper surface of the magnetic sheet 21a to form the upper surface electrode 22a. Further, using the conductive paste, for example, as shown in FIG. 5, the magnetic sheets 21c to 21f are screen-printed to form substantially U-shaped (3/4 turn) coil patterns 22c to 22f. To do. Further, the magnetic sheets 21b and 21g are screen-printed to form the connection patterns 22b and 22g so that the coil patterns 22c and 22f can be electrically connected to the via holes of the magnetic sheets 21a and 21g.

  Next, the magnetic material sheets 21a to 21g are laminated, and pressed and pressure bonded to produce a laminated body 23 as shown in FIG.

  Next, after the laminate 23 is inverted, screen printing is performed using a conductive paste, and as shown in FIG. 7, the lower surface electrode 22h is formed so as to cover the via hole.

  Next, the laminated body 23 is cut along a cutting line 24 indicated by a broken line so that the thickness T becomes smaller than the length L and the width W, and then heated in the atmosphere, for example, at a temperature of 500 ° C. The resin is burned and removed, and then a ceramic sintered body is produced by performing a firing process at a temperature of, for example, 900 ° C. for a predetermined time. Thereafter, surface polishing is performed, thereby producing a multilayer inductor.

  As described above, in the third embodiment, since both the upper surface electrode and the lower surface electrode are formed by screen printing, it is possible to perform wire bonding on the smooth upper surface electrode, and a bonding connection with high bonding strength. It is possible to easily manufacture a laminated coil component that can be In addition, since the lower surface electrode 22h is formed by printing before cutting the multilayer body 23, it is not necessary to perform a dipping process on the multilayer inductor, which is a ceramic sintered body, and productivity can be improved.

  In the third embodiment, the upper surface electrode 22a is preliminarily printed on the magnetic sheet 21a. However, the upper surface electrode and the lower surface electrode may be formed by screen printing after the laminate is formed.

  Needless to say, the present invention is not limited to the above-described embodiment, and can be changed without departing from the scope of the invention. In the first embodiment, only the via hole 10a is formed in the magnetic sheet 9a for extracting the coil conductor. However, as shown in FIG. 8, the surface of the magnetic sheet 9a is covered with the via hole 10a. It is also preferable to screen print the land pattern 25 having an arbitrary shape.

  Further, as shown in FIGS. 9A to 9C, the electrode pattern of the upper surface electrode 6 is circular 6a, square 6b, or so that the upper surface electrode 6 and the lower surface electrode 8 can be easily distinguished. May have a rectangular shape 6c, and via hole positions 26a to 26c may be provided at the peripheral edge portions of the electrode patterns 6a to 6c of the upper surface electrode for easy wire bonding.

  Further, in the first embodiment, the upper surface electrode is formed by a printing process, and in the second embodiment, the upper surface electrode is formed by a conductive sheet. Since the upper surface electrode is formed on the one end surface, the planar area of the upper surface electrode is wide. Therefore, since the planar area can be sufficiently secured, the upper surface electrode may also be formed by dipping. Also in this case, a smoother upper surface electrode can be easily obtained by appropriately plating the upper surface electrode to form a metal film.

In the above embodiment, a Zn—Ni—Cu ferrite material is used as the ceramic material. However, other ceramic materials, for example, low dielectrics (eg, relative dielectrics) mainly composed of SiO ₂ or Al ₂ O ₃ are used. Nonmagnetic powder having a rate of 30 or less) may be used.

  In the above embodiment, the multilayer inductor has been described as the multilayer coil component. However, it goes without saying that the present invention can be similarly applied to other multilayer coil components such as a multilayer impedancer.

  Next, examples of the present invention will be specifically described.

First, Fe ₂ O ₃ , NiO, CuO, and ZnO are weighed so that Fe ₂ O ₃ is 49.0 wt%, NiO is 9.6 wt%, CuO is 10.4 wt%, and ZnO is 31.0 wt%. Then, the weighed product was put into a ball mill together with water, sufficiently diffused and mixed to form a slurry, and then dried by a spray dryer to produce a ferrite raw material powder.

  Next, this ferrite raw material powder was calcined at 820 ° C. for 1 hour to cause a solid phase reaction to synthesize ferrite. Then, this synthesized ferrite was put into a ball mill together with water and pulverized, sufficiently stirred to form a slurry, and dried with a spray dryer to produce a ferrite powder.

  Next, a polyvinyl butyral resin as a binder resin and toluene and ethanol as organic solvents were added to the ferrite powder and kneaded to prepare a ferrite slurry. And using the doctor blade method, the said ferrite slurry was apply | coated to the film form on the peelable plastic film, it was made to dry, and the magnetic body sheet | seat with a thickness of 50 micrometers was produced.

  Next, a plurality of magnetic sheets prepared as described above are prepared, and a first through hole for forming a coil conductor and a second through hole for enabling electrical connection with an external electrode are provided. It was formed using a laser processing machine.

  Next, a conductive paste mainly composed of Ag is used, and a substantially U-shaped conductor pattern can be formed as a coil conductor on a plurality of magnetic sheets on which the first through holes are formed. The second through hole was filled with a conductive paste.

Next, after the magnetic sheets on which the conductor pattern is formed are appropriately laminated, the second through holes are sandwiched between the magnetic sheets filled with the conductive paste, and the pressure is 1.2 × 10 ⁷ Pa from the vertical direction. The laminate was produced by pressure bonding.

  Next, the laminate was cut so that the dimensions after firing were a length L: 1.0 mm, a width W: 1.0 mm, and a thickness T: 0.5 mm or 0.75 mm. It was heated at 0 ° C. to burn and remove the binder resin, and then fired at a temperature of 900 ° C. to produce a ceramic sintered body.

  Next, the ceramic sintered body is barrel-polished to form a corner portion in an R (R) shape to form a ferrite body, and then a conductive paste mainly composed of Ag is formed on the upper and lower surfaces of the ferrite body. Application was performed by a dip method, and then baking was performed at a temperature of 850 ° C. to form external electrodes (upper surface electrode and lower surface electrode).

  Then, using an electrolytic plating method, it is immersed in an electrolytic Ni plating solution and an electrolytic Au plating solution in order, and a 0.8 μm thick Ni film and a 0.6 μm thick Au film are applied to the surface of the external electrode. Samples of Examples 1 and 2 (multilayer inductors) were produced.

  Further, as a comparative example, the outer dimensions after firing are the same as described above so that the length L is 1.0 mm, the width W is 1.0 mm, and the thickness T is 1.00 mm, 1.25 mm, or 1.50 mm. Samples (multilayer inductors) of Comparative Examples 1 to 3 were produced by the method and procedure described above.

  Next, 30 samples of each of the examples and comparative examples were subjected to heat treatment for 1 minute at a temperature of 300 to 350 ° C. in a nitrogen atmosphere using an Au—Sn solder ribbon (Sn 20%). The product was mounted on a land portion of a circuit board, the mounting state was visually judged, and the occurrence rate of defective products was calculated with the fallen sample as a defective product.

  Next, for the sample mounted on the circuit board, a wire bonding mounter (manufactured by Kyushu Matsushita Electric Co., Ltd., SW27U-H) was used, and wire bonding was performed on the upper surface electrode under the following conditions.

[Wire bonding conditions]
Ultrasonic oscillation frequency: 60KHz
Load: 784mN
Temperature: 100 ° C
Processing time: 80ms
Wire diameter: 25 μm (Au with a purity of 99.9%)
Capillary: 1572N-15-437GM manufactured by Geyser
Next, using a ball shear tester (manufactured by Daisy Corp., Bond Tester 4000), a ball shear test in accordance with the US ASTM standard (F1269-89) is performed to measure the bonding strength, and a sample having a bonding strength of less than 70 MPa is measured. The defective product occurrence rate was calculated as a defective product.

この表１から明らかなように比較例１〜３は、厚みＴが長さＬ（＝１．０ｍｍ）及び幅Ｗ（＝１．０ｍｍ）と同等以上であるため、重心位置が高くなり、Ａｕ−Ｓｎはんだ実装を行なおうとしても転倒する試料が生じ、不良品発生率が比較例１で５％、比較例２で１０％、比較例３で３０％であった。 Table 1 shows the defective product occurrence rate in An-Sn solder mounting and wire bonding mounting.

As apparent from Table 1, in Comparative Examples 1 to 3, since the thickness T is equal to or greater than the length L (= 1.0 mm) and the width W (= 1.0 mm), the position of the center of gravity is increased. -Even if it tried to mount Sn solder, the sample which falls was produced, and the defective product generation rate was 5% in the comparative example 1, 10% in the comparative example 2, and 30% in the comparative example 3.

  Also, in wire bonding mounting, Comparative Example 1 has a cubic shape, so that it could be mounted with a bonding strength of 70 MPa or more. However, in Comparative Examples 2 and 3, there were those mounted in an inclined state on an alumina substrate. For this reason, even if the bonding connection is made, the bonding strength may be reduced, and the defective product generation rate is 10% in Comparative Example 2 and 20% in Comparative Example 3.

  On the other hand, in Examples 1 and 2, since the thickness T is smaller than the length L and the width W, Au-Sn solder mounting and wire bonding mounting can be performed in a stable state, and defective products are generated. I never did.

  In the same manner and procedure as in Example 1, length L: 1.0 mm, width W: 1.0 mm, thickness T: 0.5 mm, 0.75 mm, 1.00 mm, 1.25 mm, 1.50 mm Samples of Examples 11 and 12 and Comparative Examples 11 to 13 were prepared.

  Next, for each example and 30 comparative examples, EN-4390 manufactured by Hitachi Chemical Co., Ltd. was used as the conductive adhesive, and the conductive adhesive was cured by heat treatment at a temperature of 150 ° C. for 1 hour. Was mounted on an alumina circuit board, and in the same manner as in [Example 1], the mounting state was evaluated, and the defective product occurrence rate was calculated.

  Further, wire bonding mounting was performed on the upper electrode under the same wire bonding conditions as in [Example 1], a ball shear test was performed, the bonding strength was measured, and the defective product occurrence rate was calculated.

この表２から明らかなように比較例１１〜１３は、厚みＴが長さＬ（＝１．０ｍｍ）及び幅Ｗ（＝１．０ｍｍ）と同等以上であるため、重心位置が高くなり、また導電性接着剤実装時に位置ずれが生じ易く、不良品発生率が比較例１１で１０％、比較例１２で２０％、比較例１３で５０％となった。また、ワイヤボンディング実装においても、導電性接着剤実装の実装状態が不安定な試料もあることから、不良品発生率は比較例１１で５％、比較例１２で２０％、比較例１３で４０％となった。 Table 2 shows the defective product generation rate in the conductive adhesive mounting and the wire bonding mounting.

As is apparent from Table 2, in Comparative Examples 11 to 13, the thickness T is equal to or greater than the length L (= 1.0 mm) and the width W (= 1.0 mm), so that the center of gravity position is increased. Misalignment was likely to occur when the conductive adhesive was mounted, and the defective product generation rate was 10% in Comparative Example 11, 20% in Comparative Example 12, and 50% in Comparative Example 13. Also, in wire bonding mounting, there are samples in which the mounting state of the conductive adhesive mounting is unstable, so the defective product occurrence rate is 5% in Comparative Example 11, 20% in Comparative Example 12, and 40 in Comparative Example 13. %.

  On the other hand, in Examples 11 and 12, since the thickness T is dimensionally smaller than the length L and the width W, conductive adhesive mounting and wire bonding mounting can be performed in a stable state, and defective products are generated. I never did.

  A sample of Example 21 having a length L: 0.5 mm, a width W: 0.5 mm, and a thickness T: 0.25 mm was produced in the same manner and procedure as in [Example 1]. Similarly, samples of Comparative Examples 21 and 22 having a length L of 0.5 mm, a width W of 0.5 mm, and a thickness T of 0.50 mm and 1.25 mm were produced.

  Next, for each example and 30 comparative examples, as in [Example 1], an Au-Sn solder ribbon was used, the lower electrode was mounted on an alumina circuit board, the upper electrode was wire-bonded, and the ball A share test was conducted.

この表３から明らかなように比較例２１、２２は、厚みＴが長さＬ（＝０．５ｍｍ）及び幅Ｗ（＝０．５ｍｍ）と同等以上であるため、重心位置が高く、不良品発生率が比較例２１で２％、比較例２２で５％であった。また、ワイヤボンディング実装においても、はんだ実装の実装状態が不安定な試料もあることから接合強度が低下し、不良品発生率は比較例２１で１０％、比較例２２で２０％となった。 Table 3 shows the defective product occurrence rate in Au-Sn solder mounting and wire bonding mounting.

As is apparent from Table 3, in Comparative Examples 21 and 22, the thickness T is equal to or greater than the length L (= 0.5 mm) and the width W (= 0.5 mm). The incidence was 2% in Comparative Example 21 and 5% in Comparative Example 22. Also, in wire bonding mounting, there is a sample in which the mounting state of solder mounting is unstable, so that the bonding strength is reduced, and the defective product occurrence rate is 10% in Comparative Example 21 and 20% in Comparative Example 22.

  On the other hand, Example 21 is similar to Examples 1 and 2 in [Example 1], because the thickness T is dimensionally smaller than the length L and the width W, so that Au—Sn solder mounting and wire are stable. Bonding mounting could be performed, and no defective product was generated.

It is a perspective view which shows the mounting state of one Embodiment (1st Embodiment) of the multilayer inductor as a multilayer coil component which concerns on this invention. It is a disassembled perspective view for demonstrating the layer structure of the magnetic material sheet which comprises the said multilayer inductor. It is sectional drawing which shows 2nd Embodiment of a multilayer inductor. It is a disassembled perspective view for demonstrating the layer structure of the magnetic material sheet which comprises the laminated inductor of 2nd Embodiment. It is a disassembled perspective view for demonstrating the layer structure of the magnetic material sheet which comprises the multilayer inductor of 3rd Embodiment. It is a perspective view which shows the state which laminated | stacked the magnetic material sheet of 3rd Embodiment. It is a perspective view which shows the state which screen-printed the lower surface electrode of the laminated body of 3rd Embodiment. It is a perspective view which shows other embodiment of the magnetic material sheet of the uppermost layer in which the via hole was formed. It is a perspective view of other embodiment which shows the relationship between an upper surface electrode and a via-hole position. It is a perspective view which shows the prior art example of the chip-type electronic component mounted on the circuit board. 10 is a diagram for explaining the problem of Patent Document 1. FIG. It is a figure for demonstrating the other subject of patent document 1. FIG.

Explanation of symbols

4 Coil conductor 3 Ferrite body (ceramic body)
6 Upper electrode 8 Lower electrode 9 Magnetic sheet (ceramic green sheet)
12 Coil conductor 13 Ferrite body (ceramic body)
14 Upper electrode 15 Lower electrode 16 Magnetic sheet (ceramic green sheet)
19 Conductive Sheet 20 Conductive Sheet 21 Magnetic Sheet (Ceramic Green Sheet)
22a Upper electrode 22h Lower electrode 23 Laminate

Claims (9)

A substantially rectangular parallelepiped ceramic body in which a coil conductor is incorporated and ceramic green sheets are laminated, and an external electrode formed on the surface of the ceramic body and electrically connected to the coil conductor Laminated coil parts
The external electrode includes an upper surface electrode formed on an upper surface in the stacking direction of the ceramic green sheets and a lower surface electrode formed on a lower surface in the stacking direction, and the dimension in the stacking direction is orthogonal to the stacking direction. A laminated coil component, wherein the laminated coil component is formed to be smaller than a dimension in two directions.   The multilayer coil component according to claim 1, wherein the upper surface electrode and the lower surface electrode are formed in different shapes.   The multilayer coil component according to claim 1 or 2, wherein the upper surface electrode and the coil conductor are electrically connected in the vicinity of a peripheral edge portion of the upper surface electrode.   The multilayer coil component according to any one of claims 1 to 3, wherein at least an upper surface electrode of the upper surface electrode and the lower surface electrode constituting the external electrode is formed of a conductive sheet.   A laminated body forming step of laminating a ceramic green sheet having a coil pattern formed on a surface thereof so that a dimension in a laminating direction is smaller than a dimension in two directions orthogonal to the laminating direction to form a substantially rectangular parallelepiped laminated body; A ceramic body forming step of forming a ceramic body by subjecting the laminate to a firing process; and a top electrode forming step of forming a top electrode by performing a printing process on the top surface of the ceramic body using a conductive paste. And a lower surface electrode forming step of forming a lower surface electrode by subjecting the ceramic body to a dipping process.   A ceramic green sheet having a coil pattern formed on its surface is laminated so that the dimension in the laminating direction is smaller than the dimension in two directions perpendicular to the laminating direction, and the upper surface electrode is formed in advance by a printing process A laminated body forming step of forming a substantially rectangular parallelepiped laminated body, a ceramic body forming step of firing the laminated body to form a ceramic body, and a dipping treatment of the ceramic body A method of manufacturing a laminated coil component, comprising: a lower surface electrode forming step of forming a lower surface electrode.   A ceramic green sheet having a coil pattern formed on the surface is laminated so that the dimension in the laminating direction is smaller than the dimension in two directions orthogonal to the laminating direction, and further the ceramic green sheet having the upper electrode formed thereon is laminated. A laminate forming step for forming a substantially rectangular parallelepiped laminate, a bottom electrode forming step for forming a bottom electrode by performing a printing process on the bottom surface of the laminate using a conductive paste, and the top electrode and the bottom electrode. A method of manufacturing a laminated coil component, comprising: a ceramic body forming step of forming a ceramic body by subjecting the formed laminated body to a firing process.   A laminated body forming step in which a ceramic green sheet having a coil pattern formed on a surface thereof is laminated so that a dimension in a laminating direction is smaller than a dimension in two directions perpendicular to the laminating direction to form a substantially rectangular parallelepiped shaped laminated body; An electrode forming step of forming a top electrode and a bottom electrode by performing a printing process on the top and bottom surfaces of the laminate using a conductive paste; and a firing process for the laminate on which the top electrode and the bottom electrode are formed. And a ceramic body forming process for forming the ceramic body. A multilayer coil component mounting structure using the multilayer coil component according to any one of claims 1 to 3,
It is mounted on the circuit board so that the lower surface electrode of the multilayer coil component is electrically connected to the circuit board, and the upper surface electrode of the multilayer coil component is connected to a bonding wire. Mounting structure for laminated coil parts.

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