JP2007123678A - Ceramic laminate electronic component and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ceramic laminate electronic component and a manufacturing method thereof wherein its electric property is stable and highly reliable, and it has a higher Q-value than a conventional one, and further, its manufacturing cost is low, and especially, it is used in a high-frequency region. <P>SOLUTION: With respect to the structure of the ceramic laminate component wherein conductor layers and ceramic layers are laminated alternately, there are included conductors in its one or more portions, and the whole periphery of each conductor is covered with ceramic materials substantially same with each other. Each conductor has such a nearly trapezoidal sectional shape that the average length (average width) of its major and minor sides is not longer than 60 μm, the ratio of its minor side to its major side is not smaller than 0.7 and is smaller than 1.0, and further, its thickness is not smaller than 10 μm. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a high-frequency multilayer ceramic electronic component used in a mobile device such as a mobile phone terminal and a manufacturing method thereof.

  Hereinafter, a conventional high frequency multilayer ceramic electronic component and a manufacturing method thereof will be described. Conventional high-frequency multilayer ceramic parts such as resonators are manufactured by using a screen printing method as shown in FIGS. 9A, 9B, and 9C (see, for example, Patent Document 1).

  As shown in FIG. 9A, a screen plate 102 having an opening 103 for forming a desired conductor pattern is aligned at a desired position on the ceramic green sheet 101. A conductive paste 104 such as silver is supplied onto the screen plate 102 and moved while being pressurized in the direction of the arrow using a squeegee 105. Thereby, the conductor paste 104 is applied onto the ceramic green sheet 101 through the opening 103 of the screen plate and dried to form an internal conductor pattern.

  Next, as shown in FIG. 9B, another ceramic green sheet 107 is laminated on the ceramic green sheet 101 having the inner conductor pattern 106 printed on the upper surface, and pressing is performed to bring these sheets into close contact with each other. Next, a sintering process is performed. FIGS. 9C and 9D are cross-sectional photographs of internal conductors of a conventional high-frequency multilayer ceramic component formed by such a method. As is clear from FIGS. 9C and 9D, the central portion of the inner conductor pattern 106 is flat, but the side end portion 108 has a sharp tapered shape. When a high-frequency current flows through the conductor layer, the high-frequency current tends to concentrate on the surface of the conductor layer due to the skin effect. In the conductor layer having a sharp pointed shape as shown in FIGS. 9C and 9D, the high-frequency current is concentrated on the side surface end portion 108, so that the electrical resistance of the conductor layer increases and the Q value decreases. In particular, when the electrode width is narrowed, the influence of current concentration on the end portion 108 becomes relatively high, so that the Q value is greatly reduced. Further, in the screen printing method, even if the screen plate has a thin mesh wire diameter of about 15 μm, it is difficult to reliably and stably form a fine conductor layer of 60 μm or less.

  On the other hand, as a method for solving the above problems, a technique using an intaglio transfer method is disclosed (for example, see Patent Document 2). According to this method, a narrow conductor layer can be formed reliably and stably, and the conductor cross-sectional shape is substantially trapezoidal, and there is no side end taper, and a conductor layer having a high Q value can be obtained. It is said that. The procedure of this construction method will be described based on FIG.

  First, a flexible resin film (such as polyimide) 113 is prepared. A groove 114 corresponding to the conductor layer pattern is formed on the film surface by an excimer laser or the like, and the conductor paste 115 is filled in the groove. As a method for filling the groove with the conductive paste, firstly, the entire surface of the film is covered with a conductive paste, and a solid ceramic squeegee is used to scrape off the excess paste on the film surface, leaving only the groove in the paste. Yes.

  Next, an insulating substrate 111 is prepared. It is disclosed that 111 is a sintered dielectric material, a magnetic material, and a sheet (green sheet) before sintering. A resin layer 112 as an adhesive layer is formed on at least one surface of the insulating substrate. When 111 is a green sheet, since the resin component is contained in the green sheet, the formation of the resin layer 112 can be omitted.

  An intaglio resin film 113 in which the groove 114 is filled with the conductor paste 115 is bonded to a predetermined position on the insulating substrate 111 on which the resin layer 112 is formed, and the conductor paste 115 is transferred to the insulating substrate 111 by heating and pressurizing. The film 113 is peeled off. When this substrate is fired at a temperature at which the conductor paste is densely sintered, a fine conductor layer having a substantially trapezoidal cross-sectional shape of the conductor and having no side end taper is formed on the substrate surface as shown in FIG. 117 is formed.

  In order to protect the conductor layer, prevent migration, and further form a conductor layer on the conductor layer, an insulating paste 118 made of, for example, crystallized glass is formed on the conductor layer, and the temperature at which the insulating paste 118 is densified. Process with. Through the above process, a substrate composed of the fine conductor layer 117 and the insulating layer 119 covering the surface thereof is completed on the insulating substrate 111 as shown in FIG.

When the second conductor layer is formed on the conductor layer, the via conductor 120 having a high height is formed by deepening the groove of the intaglio resin film as shown in FIG. Then, polishing is performed until the via conductor 120 is exposed from the insulating layer 119 as shown in FIG. 11B, and the lead conductor 121 is formed by a screen printing method or the like as shown in FIG. 11C.
JP 2000-156621 A Japanese Patent No. 3039285

  The intaglio printing method has an excellent conductor layer formation in which the cross-sectional shape is substantially trapezoidal and there is no taper of the side edge, and the conductor layer can be formed with a small variation in electrode width and thickness and stable electrical characteristics. Although it is a construction method, the following problems have been confirmed by the inventors' investigation.

  First, in the step of firing the conductor layer, the resin layer 112 as an adhesive layer disappears before the conductor paste 115 is sintered, so that the conductor layer 117 after firing is formed in a distorted shape on the insulating substrate 111. In the worst case, a short circuit failure or an open failure may occur.

  Further, in order to fix the conductive paste 115 to the insulating substrate 111, it is necessary to contain glass or the like in the conductive paste 115, so that the electrical resistance of the conductive layer increases and the Q value decreases.

  Further, in order not to damage the insulating substrate 111 such as distortion or deformation, the material of the insulating layer 119 needs to be a material that is densely sintered at a lower temperature than the insulating substrate 111. A material different from the material of the insulating substrate 111 and the material of the insulating layer 119 must be selected. If the thermal expansion coefficients of both materials are matched and an insulating layer material with high wettability is not selected for the insulating substrate, defects at the interface between the insulating substrate 111 and the insulating layer 119 may occur. It is a difficult task to select, and there are inherent factors that cause defects at the interface between the insulating substrate 111 and the insulating layer 119. For example, in order to manufacture a small and high-performance directional coupler (coupler), it is necessary to use silver having good conductivity for the conductor layer and to narrow the distance between the two conductor layers. If there are inherent factors causing defects at the interface, silver migration may occur through the defects at the interface, and there is concern about reliability.

  As shown in FIG. 11C, in order to form the second conductor layer that is electrically joined to the conductor layer formed by the intaglio printing method, a complicated process as shown in FIG. In particular, in order to form the via conductor 120 having a high height, it is not sufficient to fill the via conductor 120 with a squeegee, and an operation such as applying a centrifugal force is required, which is one of the causes of increasing the cost.

  In particular, when the insulating substrate is a sintered substrate, in the process of transferring the conductive paste filled in the intaglio resin film in the processes (e) and (f) of FIG. 10 to the substrate, the substrate is cracked due to warping or undulation of the insulating substrate. In order to prevent chipping, high pressure cannot be applied, and it is necessary to hold at high temperature for a long time. Therefore, the intaglio resin film stretches every time it is used, and the dimensional accuracy deteriorates. Therefore, the life of the intaglio resin film is short, which is one of the causes for increasing the cost.

  Therefore, the present invention has been made in view of such a problem, and an intaglio printing method in which a conductor layer without a taper at the side end can be formed, variation in electrode width and thickness is small, and electrical characteristics are stable. It is a further object of the present invention to provide a multilayer ceramic electronic component used in the high frequency region, which has high reliability, a higher Q value, and a low manufacturing cost, and a manufacturing method thereof.

  In order to achieve the above object, the present invention has the following configuration.

  In a ceramic laminated part in which conductor layers and ceramic layers are alternately laminated, the conductor has a substantially trapezoidal cross-sectional shape, and the average length (average width) of the long and short sides of the trapezoid is 60 μm or less, the long side And a short ceramic in which the ratio of the short side is 0.7 or more and less than 1.0 and the thickness is 10 μm or more at least in part, and the entire circumference of the conductor is covered with the essentially same ceramic material It is an electronic component, and particularly has an effect + that a multilayer ceramic electronic component having a high Q value at a high frequency and excellent in reliability can be realized.

  In addition, a step of forming a ceramic green sheet by adding a binder resin and a plasticizer to a ceramic raw material powder before firing that becomes a ceramic layer after firing, and laminating a plurality of the ceramic green sheets, before firing to become a ceramic layer after firing the ceramic green A step of forming a ceramic green sheet by adding a binder resin and a plasticizer to the ceramic raw material powder, a step of laminating a plurality of the ceramic green sheets to form a ceramic green laminate, and a surface of a flexible resin film An intaglio film manufacturing process for forming grooves, a filling process for filling the grooves of the intaglio film with a conductive paste, a step of volatilizing and drying a solvent contained in the filled conductive paste, and the intaglio film And the ceramic green sheet laminate together A transfer step for applying pressure, a film peeling step for peeling the intaglio film from the ceramic green sheet laminate and transferring the conductive paste onto the ceramic green sheet laminate, and a ceramic green A step of covering a conductor pattern formed on the surface of the laminate with a ceramic paste made of essentially the same material as the ceramic green sheet, and a step of dividing the ceramic green laminate to which the conductor pattern is transferred into a desired shape into a plurality of shapes And heating the divided ceramic green laminate to disperse the resin component, and then firing the ceramic material at a temperature at which the ceramic material is densely sintered. Has a high Q value, excellent reliability, and low manufacturing costs It has the effect that can be achieved a production method of layer ceramic electronic component.

  The multilayer ceramic electronic component of the present invention and the method for manufacturing the same have a high Q value especially at high frequencies because the cross-sectional shape is substantially trapezoidal and there is no taper at the side edges even when the electrode width is as thin as 60 μm. The electrical characteristics are stable due to small variations, and the entire periphery of the conductor layer is covered with essentially the same ceramic material, so it is highly reliable and electrically connected to the conductors of other layers. The via-hole electrode to be connected is formed by drilling a ceramic green sheet, filling it with a conductor, and firing it. Therefore, the manufacturing cost is low compared to the conventional intaglio printing method, and the transfer from the intaglio film to the green sheet laminate is low and short. Since it is possible in time, the durability of the intaglio resin film is high, and the manufacturing cost can be reduced. Therefore, the present invention is useful as a high-performance, highly reliable and inexpensive multilayer ceramic electronic component and a method for manufacturing the same.

(Embodiment 1)
Hereinafter, a multilayer ceramic electronic component and a manufacturing method thereof according to the present invention will be described with reference to the drawings.

  FIG. 1 is a manufacturing process diagram of the multilayer ceramic electronic component of the present invention.

  First, an arbitrary number of ceramic green sheets 1 are prepared. Ceramic green sheets are prepared by mixing a slurry obtained by adding a binder resin, a plasticizer, and a solvent to a ceramic powder before firing, which becomes a ceramic layer of a multilayer ceramic electronic component, and mixing it on a carrier film such as a PET film by a method such as a doctor blade. Sheet molded. The ceramic material to be used is not particularly specified, but when manufacturing multilayer ceramic parts for high frequency such as inductors, stripline resonators, directional couplers (couplers), balanced / unbalanced impedance matching devices (baluns), the inner conductor In addition, when silver having a good conductivity and a purity of 95% by weight or more is used, a high-performance component can be obtained. Therefore, a material that is densely sintered at a temperature lower than the melting point of silver, 961 ° C., is preferable. Examples thereof include a glass ceramic mixture in which alumina and glass are mixed at a weight ratio of about 1: 1, and a low-temperature sintered ferrite obtained by adding a low-temperature sintering agent or glass to a ferrite material.

  The green sheet is formed to a thickness of 50 to 100 μm, and a plurality of layers are laminated and pressed to produce a ceramic green laminate 2 having an arbitrary thickness.

  On the other hand, a polyimide film 3 having a thickness of 125 μm is prepared, and grooves 4 corresponding to the conductor pattern are formed by an excimer laser. FIG. 1C corresponds to a cross-sectional view taken along line AB in FIG. The depth of the groove is arbitrary, but if it is too shallow, the thickness of the conductor layer becomes thin and the resistance value becomes high, and if it is too deep, it becomes difficult to fill and transfer the paste in the subsequent process, so the depth is 20 to 30 μm. It is desirable. The cross section of the groove 4 is a tapered cross section as shown in FIG. This is for facilitating transfer of the conductor paste in a later step, and the taper ratio is preferably 0.7 or more and less than 1.0 from the viewpoint of characteristics and transferability. Although the thickness and material of the resin film are not limited, it is preferable to determine the material and thickness that are difficult to stretch due to heat and pressure because they are subjected to pressurization and heating processes in the subsequent steps.

  In order to fill the conductor paste 5 in the groove 4 formed by the excimer laser, first, the conductor paste is solid-printed on the polyimide film groove forming surface and the whole is covered with the conductor paste. Thereafter, while the paste is not dried, the conductive paste adhered to the polyimide film surface is scraped off with a squeegee made of zirconia ceramic having a sharp blade and a sharp edge. After scraping several times, almost no conductor paste remains on the surface, and it is dried at 150 ° C. for 3 minutes. When dried, the conductive paste shrinks and the central portion is recessed, so the above operation is repeated 2-3 times. Then, the conductor paste 5 is completely filled in the groove 4 as shown in FIG. A small amount of conductor paste may remain on the film surface, so it is better to wipe off with pure water.

  The ceramic green sheet is formed on the surface of a carrier film such as a PET film, but the resin component is segregated on the carrier film side. This is presumably because when the ceramic slurry dries, the solvent dries from the surface, and finally the solvent in which the resin component is dissolved dries on the carrier film surface. Therefore, usually, the ceramic green sheet is almost always more adhesive on the carrier film side. FIG. 1 (e) shows a process in which a polyimide film filled with a conductor paste 5 in a groove 4 is attached to a ceramic green laminate. The ceramic green laminate is disposed on the side where the carrier film is attached to the polyimide film. However, it is preferable that the polyimide film 3 of FIGS. 1E to 1F is peeled off and only the conductive paste 5 is easily transferred to the green laminate.

  The conductor paste 5 transferred to the ceramic green laminate is solid-printed with an insulating paste made of essentially the same material as the ceramic material constituting the ceramic green sheet to completely cover the conductor paste 5. The insulating layer 6 is preferably 1.5 times thicker than the conductor layer. This is because if the thickness is smaller than this, the conductive paste 5 may not be completely covered with the insulating layer 6 due to the occurrence of pinholes during solid printing.

  When the green substrate of FIG. 1 (g) is fired at a temperature at which the ceramic material is densely fired, the ceramic laminate 8 and the insulating layer 9 are essentially the same material as shown in FIG. 1 (h). A conductor layer 7 having a substantially trapezoidal cross section as shown in FIG. 3 is formed in a monolithic ceramic substrate.

  FIG. 3 (a) schematically shows a cross section of the conductor layer. In the scope of the present invention, in view of manufacturability and electrical characteristics, the average electrode width c is 60 μm or less, the taper b / a is 0.7 or more and less than 1.0, and the electrode thickness d is not able to be stably formed by the screen printing method. It is defined as 10 μm or more. FIG. 3B is a cross-sectional photograph of a conductor layer actually produced in the above manufacturing process, and a conductor layer having an average electrode width of 46 μm, a taper of 0.84 and a thickness of 15 μm and a substantially trapezoidal cross-sectional shape can be formed.

  FIG. 4 is a manufacturing process diagram for electrically connecting the conductor layer formed by the intaglio transfer method and the side surface of the substrate using via electrodes.

  In the step of producing the ceramic green laminate of FIGS. 4A to 4B, a via conductor 10 is formed by opening a hole in the green sheet as the uppermost layer portion and filling the hole with a conductor paste. An internal conductor layer 11 that connects the conductor 10 and the side surface of the substrate is formed by a screen printing method or the like to produce a ceramic green laminate as shown in FIG. Subsequent steps are exactly the same as those in FIG. 1, and a substrate having a structure as shown in FIG. 4H or FIG. 5 can be manufactured.

  FIG. 6 is an effective manufacturing process diagram when it is difficult to transfer the conductor paste 5 filled in the grooves 4 of the intaglio film to the ceramic green laminate. A process different from the manufacturing process diagram shown in FIG. 1 is a process of attaching the adhesive resin layer 14 to the ceramic green laminate. As the adhesive resin layer, a material obtained by dissolving 5% by weight of PVB resin as a binder and 1% by weight of dibutyl phthalate as a plasticizer in a solvent such as butyl acetate, and forming it thinly on a carrier film such as a PET film is used. This is not the case. By sticking this adhesive resin layer 14, the transferability of the conductive paste 5 to the ceramic green laminate 2 can be dramatically improved, the temperature and pressure in the transfer process can be greatly reduced, and the press time is also greatly increased. Can be shortened. Therefore, it is possible to produce a multilayer ceramic component with suppressed dimensional accuracy and with reduced elongation of the ceramic green sheet.

  However, if the adhesive resin layer 14 is thicker than 5 μm, defects such as holes occur at the interface between the fired insulating layer 9 and the ceramic laminate 8, resulting in a problem in reliability. The thickness of the adhesive resin layer 14 is 5 μm or less. It is preferable that

  FIG. 7 is a diagram illustrating in detail the process of dividing the ceramic green laminate having the insulating layer 6 into a desired shape. FIG. 7A shows a method in which the insulating layer 6 is solid-printed and both the insulating layer 6 and the ceramic green laminate 2 are pressed and cut by the cutter blade 15. In this case, since the insulating layer 6 is a softer material than the ceramic green laminate, a defect may occur at the interface after cutting. Such a case can be avoided by not printing the insulating layer 6 on the cut portion as shown in FIG. Further, as shown in FIG. 8, the ceramic green sheet 16 is laminated on the insulating layer 6 and integrated by pressurization, so that the occurrence of defects at the time of pressing and cutting can be suppressed.

  According to the manufacturing method of the present invention, there is an effect that a multilayer ceramic electronic component having high performance, high reliability, and low cost and a method for manufacturing the same can be obtained. High performance, high reliability of mobile devices such as mobile phones, Useful for cost reduction.

Manufacturing process diagram of multilayer ceramic electronic component according to Embodiment 1 of the present invention The top view of the intaglio film with grooves formed in the resin film Same cross-sectional view of conductor layer after firing Manufacturing process diagram of multilayer ceramic electronic components including via conductors Same cross-sectional view after firing of multilayer ceramic electronic component including via conductor Manufacturing process diagram of multilayer ceramic electronic parts using adhesive resin layer Same as above, illustration of division process of multilayer ceramic electronic parts Explanatory drawing which shows an example of the manufacturing process figure of a multilayer ceramic electronic component (A) (b) Manufacturing process diagram of conventional multilayer ceramic electronic component (screen printing method), (c) (d) Cross-sectional view of conductor layer after firing of conventional multilayer ceramic electronic component Conventional manufacturing process diagram (intaglio transfer method) Via conductor formation method explanatory drawing in the conventional manufacturing process (intaglio transfer method)

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ceramic green sheet 2 Ceramic green laminated body 3 Resin film 4 Groove 5 Conductive paste 6 Insulating paste 7 The conductor after baking 8 The ceramic laminated body after baking 9 The insulating layer after baking 10 Via conductor 11 Internal conductor layer 12 Via after baking Conductor 13 Internal conductor layer after firing 14 Adhesive resin layer 15 Cutter blade 16 Ceramic green sheet 101 Ceramic green sheet 102 Screen plate 103 Screen plate opening 104 Conductor paste 105 Squeegee 106 Internal conductor pattern 107 Ceramic green sheet 108 Conductor side edge 111 Insulating Substrate 112 Resin Layer 113 Resin Film 114 Groove 115 Conductor Paste 116 Conductor Paste Transferred to Insulating Substrate 117 Conductive Layer After Firing 118 Insulating Paste 119 Insulating Layer 1 After Firing 0 via conductors 121 lead conductor by intaglio transfer method

Claims (10)

In a ceramic laminated part in which conductor layers and ceramic layers are alternately laminated, the conductor has a substantially trapezoidal cross-sectional shape, and the average length (average width) of the long and short sides of the trapezoid is 60 μm or less, the long side And a conductor having a short side ratio of 0.7 or more and less than 1.0 and a thickness of 10 μm or more at least in part, and the entire circumference of the conductor is covered with essentially the same ceramic material. Multilayer ceramic electronic parts characterized by 2. The multilayer ceramic electronic component according to claim 1, wherein the conductor layer is composed of 95% by weight or more of silver, and the ceramic layer material is ceramic that can be fired simultaneously with the conductor layer material. 3. The substantially trapezoidal conductor layer forms any one of an inductor, a stripline resonator, a directional coupler (coupler), and a balanced / unbalanced impedance matching device (balun). Multilayer ceramic electronic components. A step of forming a ceramic green sheet by adding a binder resin and a plasticizer to the ceramic raw material powder before firing to become a ceramic layer after firing;
Laminating a plurality of the ceramic green sheets to form a ceramic green laminate;
An intaglio film manufacturing process for forming grooves on the surface of the resin film having flexibility;
A filling step of filling the grooves of the intaglio film with a conductive paste;
Evaporating and drying the solvent contained in the filled conductive paste;
A transfer process in which the intaglio film and the ceramic green sheet laminate are bonded together, and temperature and pressure are applied,
A film peeling step of peeling the intaglio film from the ceramic green sheet laminate and transferring the conductive paste onto the ceramic green sheet laminate to form a conductor pattern;
Covering the conductor pattern formed on the surface of the ceramic green laminate with a ceramic paste made of essentially the same material as the ceramic green sheet;
A step of dividing the ceramic green laminate to which the conductor pattern is transferred into a desired shape;
2. The multilayer ceramic electronic component according to claim 1, further comprising a firing step in which the ceramic material is heated to disperse the resin component and then fired at a temperature at which the ceramic material is densely sintered. Manufacturing method. In the transfer step, the two main surfaces of the ceramic green laminate are compared, and an intaglio film is bonded to the surface on which more resin components contained in the green sheet are segregated, and the intaglio film is filled in the recesses. 5. The method for producing a multilayer ceramic electronic component according to claim 4, wherein the conductive paste is transferred. 5. The method of manufacturing a multilayer ceramic electronic component according to claim 4, wherein the thickness of the ceramic paste layer is 1.5 times or more the thickness of the conductor pattern. In the step of laminating a plurality of the ceramic green sheets to form a ceramic green laminate, a via hole conductor forming step in which a hole is formed in the ceramic green sheet and a conductor paste is filled therein, and the ceramic green sheet is formed into the ceramic green laminate. A portion of the conductor layer transferred from the intaglio film is connected to the via hole conductor, and the via hole conductor is electrically connected to the internal conductor layer formed in the ceramic laminate. The method for producing a multilayer ceramic electronic component according to claim 4, wherein: In the transfer step, after an adhesive resin layer having a thickness of 5 μm or less is formed on the surface of the ceramic green sheet laminate, the intaglio film and the ceramic green sheet laminate are bonded together via the adhesive resin layer, and the concave portion of the intaglio film is filled. 5. The method for producing a multilayer ceramic electronic component according to claim 4, wherein the conductive paste is transferred. 5. The method of manufacturing a multilayer ceramic electronic component according to claim 4, wherein the ceramic paste layer is not formed in a portion divided into a plurality of portions. 5. The method of manufacturing a multilayer ceramic electronic component according to claim 4, wherein after the step of covering the conductor pattern with the ceramic paste, a ceramic green sheet is stacked on the ceramic paste layer and press-integrated.

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