JP4291198B2 - Method for forming external electrode built-in layer and preventing peeling, and method for manufacturing multilayer electronic component - Google Patents

Description

  The present invention relates to a method for forming an external electrode built-in layer and preventing peeling, and a multilayer electronic component, a multilayer substrate, a module, and the like using the method.

  In general, when manufacturing a chip-type electronic component, an electrode material is applied to each end of the chip-type electronic component that is made into individual components, or after being dried, dried, and then baked. An electrode is produced.

  If the corners of the ceramic chip before application of the external electrode material are in an edged state during the production of the external electrode, the thickness of the application will be reduced only at that part, and the adhesion between the external electrode material and the ceramic chip will be reduced. And the external electrodes at the corners are easily missing or peeled off (see FIG. 1).

  As a solution to this problem, a method of rounding (R) the corners of the ceramic chip by performing barrel polishing or the like in the state of the ceramic chip is generally performed. When rounded, there is an advantage that the thickness of the application of the external electrode material is not extremely reduced, and the contact area between the external electrode material and the ceramic chip is increased, so that the adhesion is improved (see FIG. 2).

  However, even if the corners of such a chip are rounded, the contact area between the ceramic chip and the external electrode material inevitably decreases with the recent miniaturization of electronic components, and the entire external electrode is missing or peeled off. There is a problem that it is easy (see FIG. 3).

  As a cause of the peeling of the external electrode, there is a factor caused by thermal stress caused by soldering or heat generation of parts in addition to those caused by external stress, and measures for preventing the peeling of electronic parts are required.

The following prior art exists regarding the method of preventing peeling of the external electrode of such an electronic component.
A method of providing unevenness of conductive silicon inside the external electrode, causing internal peeling inside the external electrode by the elasticity of conductive silicon, and absorbing stress (Patent Document 1). In order to prevent the external electrode adjacent to the insulating material from being exfoliated with the peeling of the insulating material filled in the groove where the internal electrode is exposed, the inner wall of the groove (on the electronic component main body side) is provided with irregularities made of ceramic particles for insulation. A method for enhancing the bondability with a material (Patent Document 2). A method of forming concavities and convexities on the bonding surface of an electrode in order to increase the bonding strength (using a conductive adhesive) between an electrode of an electronic component and a land of a substrate (Patent Document 3)
JP-A-8-203770 JP2001-244513 JP 2002-57187 A

  Patent Document 1 relates to a method for obtaining a highly reliable ceramic electronic component capable of absorbing external force applied to an external electrode and preventing tearing of the external electrode layer. The external electrode includes a first layer formed of a baking layer of a conductive paste. A second electrode layer made of a conductive resin is formed on the surface of the electrode layer. The second electrode layer is formed dispersed on the surface of the first electrode layer. The third electrode layer made of the Ni plating layer has a region that is directly bonded to the first electrode layer. A fourth electrode layer made of an Sn plating layer is formed on the surface of the third electrode layer. The second electrode layer is composed of a conductive resin layer formed by applying a silicon-based conductive resin or the like and curing it. The conductive resin layer has lower strength and higher elasticity than the other electrode layers. Therefore, the effect | action which relieves the stress applied from the outside is show | played. In this document, the second layer of the external terminal electrode is formed by dispersing a silicon-based conductive resin, and peeling is caused at the interface between the conductive resin layer and the other electrode layer. (Relative stress and thermal stress). Since the second layer is formed by dispersion, irregularities are formed.

  Patent Document 2 includes a first external electrode that is provided on each of different side surfaces of the element body and electrically connects the first internal electrodes, and a second external electrode that electrically connects the second internal electrodes. A concave groove exposing the end of the second internal electrode is formed on the side surface of the element body where the first external electrode is formed, and the first side electrode is formed on the side surface of the element body where the second external electrode is formed. A concave groove in which the end of the internal electrode is exposed is formed, and the concave groove is filled with an insulator, and ceramic particles constituting the porcelain protrude from the inner surface of the concave groove to form irregularities. In this document, when a high electric field and high pressure are applied at a high temperature and driven continuously for a long time, the insulator in the groove formed between the piezoelectric ceramics deteriorates, and the gap between the groove and the insulator In order to solve the problem that a gap is generated and the external electrode is easily peeled off from the side surface of the actuator body, by forming the irregularities by projecting the ceramic particles constituting the porcelain on the inner surface of the groove, the groove and the insulator It is invention which prevents generation | occurrence | production of the clearance gap between.

  Patent Document 3 is characterized in that in an electronic component mounting structure in which an electrode of an electronic component and a land of a substrate are joined with a thermosetting conductive adhesive, irregularities are formed on the surface on the land side of the electrode. It relates to the invention. This document reinforces the adhesive force between the conductive adhesive and the bump so that it can withstand thermal stress to the joint due to the temperature change from heating to curing to normal temperature. Is a chip mounting structure and a chip mounting method that do not peel off, and in an electronic component mounting structure in which a land of a substrate is bonded with a thermosetting conductive adhesive, irregularities are formed on the land side surface of the electrode. It is characterized by this.

  The present invention pays attention to the structure in which ceramic green sheets are laminated, and changes the size or pattern of the laminated sheets in each layer at the boundary surface between the part that becomes the external terminal electrode of the product and the ceramic part to make it uneven. The purpose of this is to prevent the external electrodes from peeling off or missing.

  In a ceramic electronic component formed by laminating ceramic green sheets, a general method for forming external terminal electrodes is to cut the laminated ceramic green sheets to a predetermined size and expose the internal electrode drawer by barrel polishing or the like. In this method, a conductive paste is applied to the cut surface.

  The present invention employs a method of patterning external terminal electrodes on a ceramic green sheet and forming the external terminal electrodes together with lamination, and based on the idea of forming irregularities on the surface corresponding to the cut surface, the irregularities are made ceramic. It is characterized in that the green sheet is formed by slightly shifting the dimensions, and this method prevents the peeling or missing of the external electrode. This method is an invention that is completely different from the above-described conventional method for forming an external terminal electrode in which the external electrode is formed by cutting after machining and then forming the external electrode.

Therefore, one embodiment of the present invention is a method for manufacturing a multilayer electronic component composed of a laminate of ceramic green sheets,
Including patterning external terminal electrodes on the ceramic green sheet and laminating so as to form external terminal electrodes so as to provide unevenness at the boundary between the ceramic region and the external terminal electrode region of the electronic component, A method for manufacturing a multilayer electronic component. Another embodiment of the present invention is the above-described method for manufacturing a multilayer electronic component, wherein the unevenness slightly shifts a boundary position between the ceramic region and the external terminal electrode region of the electronic component. The external terminal electrode is formed by laminating patterned ceramic green sheets.

  Another embodiment of the present invention is the above-described method for manufacturing a multilayer electronic component, wherein the unevenness causes the boundary between the ceramic region and the external terminal electrode region of the electronic component to be inclined in the cross-sectional direction. In this state, the external terminal electrode is formed by laminating patterned ceramic green sheets.

  Yet another embodiment of the present invention is a method for manufacturing a multilayer electronic component as described above, wherein the patterning of external terminal electrodes included in the ceramic green sheet is performed by laminating the plurality of types of ceramic green sheets. By doing so, the boundary between the external terminal electrode and the unnecessary region such as the cutting margin is formed into a substantially spherical round shape.

  Yet another embodiment of the present invention is a multilayer ceramic electronic component formed by the method for manufacturing a multilayer electronic component described above.

  As used herein, “ceramic region” means an insulator region in a ceramic green sheet laminate corresponding to an insulating part of a multilayer electronic component, and “unnecessary region” means a ceramic green sheet laminate. It means the cutting allowance area or disappearance area in the body.

  The method for manufacturing a multilayer electronic component according to the present invention is characterized in that the multilayer structure of the multilayer ceramic electronic component is used to form irregularities on the boundary surface between the ceramic region of the electronic component and the external terminal electrode region, or the multilayer ceramic electronic In terms of having an application forming method that can cope with the miniaturization of parts, it is possible to obtain a small, low-cost and highly reliable multilayer ceramic electronic component, and further, peeling, missing, etc. of external terminal electrodes It can be effectively prevented.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  FIG. 4A shows a method of patterning external terminal electrodes on a ceramic green sheet to form external terminal electrodes together with lamination, and slightly pattern boundaries between ceramic (insulator) portions 4 and external electrode portions (conductors) 5. It is shown that when a multilayer ceramic electronic component is formed by laminating ceramic green sheets 7 having a plurality of different patterns, the boundary between the ceramic portion and the external electrode portion in the cross-section is uneven. . In the formation and lamination process of ceramic green sheets, the surface area of the boundary surface between the ceramic part and the external electrode part is increased by adopting patterning that makes the boundary between the ceramic part and the external electrode part uneven. It is possible to manufacture a multilayer ceramic electronic component having high reliability that the adhesion is remarkably improved and the external electrode is hardly peeled off due to various stresses.

  According to the method of Example 1, there is a concern that the number of patterns of the ceramic green sheet is a combination of the pattern of the internal electrode and the pattern of the external electrode, and the patterning becomes very large. Therefore, as a coping method, the present embodiment shows a method for obtaining the same effect as in the first embodiment, assuming that the pattern boundary between the ceramic portion and the external electrode portion is the same.

  In this embodiment, in the ceramic green sheet 7 including the external electrode region 5, the boundary between the external electrode region 5 and the ceramic (insulator) region 4 is tapered as viewed from the cross-sectional direction. As an example of the method of tapering, it is possible to taper or reverse taper depending on the groove pattern formation conditions by photolithography.

  FIG. 4b shows an example of a single taper, and an example of the forming method is shown in FIGS. 5 (a) and 5 (b).

  In FIG. 5A, a negative photosensitive insulator material 8 is coated on a substrate, exposed on the top surface using a photomask 10, and a through groove pattern is produced by a development process. The material (cutting allowance) 9 is filled, and mask exposure and development are performed to taper. This is filled with a conductor material (external electrode) 11 to produce a ceramic green sheet.

  FIG. 5B shows a ceramic green sheet in which a positive photosensitive insulator material (cutting allowance) 9 is applied on a base material and a built-in external electrode is produced by the same process.

  After laminating and pressing these ceramic green sheets 7 to form a laminated body, the cutting margin is eliminated by cutting or disappearing treatment, and firing is performed to obtain individual multilayer electronic components.

  For the substantially spherical rounded layer in the structure shown in FIG. 4c, in order to omit the barrel polishing step and to obtain a smooth substantially spherical round shape, the external electrode region 5 and the cutting margin region 6 are formed by the following steps. An angle may be provided on the boundary surface.

  In the process of FIG. 6, a smoother substantially spherical round shape is obtained by tapering the boundary of the material according to the conditions at the time of exposure and development and laminating a plurality of ceramic green sheets so that the taper is continuous. Furthermore, the taper on the opposite side bites into the insulator layer, and higher adhesion strength is obtained.

  As shown in FIG. 6 (a), a negative photosensitive insulator material 12 is applied on a substrate, exposed on the top surface using a photomask 10, and a through groove pattern is produced by a development process. A photosensitive insulating material (cutting allowance) 13 is filled, masked and developed to taper. This is filled with a conductor material (external electrode) 14 to produce a ceramic green sheet.

  As shown in FIG. 6 (b), a positive photosensitive insulator material (cutting allowance) 13 is applied on a base material, the top surface is exposed using a photomask, and a through groove pattern is produced by development processing. Then, a conductive material (external electrode) 14 is filled therein, and the obtained sheet is exposed and developed using a photomask to fill the ceramic slurry 12. Here, the sheet filled with the conductor material is inverted depending on the slurry filling property, but depending on the target angle, the inversion is not necessary, or a reverse taper may be provided from the beginning.

  FIG. 6C shows a case where a positive photosensitive insulator material 13 is applied on a substrate and is tapered in the same manner as in FIG. 6A. In FIG. 6C, before the second exposure with the photomask, the inversion is performed according to the filling property of the subsequent electrode paste. However, the inversion is unnecessary depending on the target angle, or the first A reverse taper may be applied.

  Each of these ceramic green sheets 7 is patterned and laminated so that the corners of the multilayer electronic component have a substantially spherical round shape, and after pressing to form a laminate, a cutting margin is formed by cutting or disappearing treatment. Can be eliminated and fired to obtain individual multilayer electronic components.

  It is well known that the pattern boundary is tapered in exposure / development. For example, for negative photosensitive materials, the taper is used when the exposure amount is large and the development is weak (for example, when the spray pressure in the spray phenomenon is low and / or when the spray time is short). Can be attached. On the other hand, when the exposure amount is normal and the development is strong (when the spray pressure is high and / or the spray time is long, or both), a reverse taper can be provided. By making full use of the above combination, a desired angle can be obtained to form a substantially spherical round shape, but of course it depends on the material and thickness, so it is optimal for the desired substantially spherical round shape. A range is determined.

  Further, as the photomasks used in FIGS. 5 and 6, various patterns of photomasks are arbitrarily selected according to the target ceramic green sheet pattern shape.

  The material for the cutting allowance can be selected arbitrarily, but any material that disappears by a predetermined treatment such as washing with water, heat, photolithography, etc. is preferable in that the cutting step can be eliminated.

  The manufacturing method of the multilayer electronic component according to the present invention uses the multilayer structure of the chip-type ceramic electronic component to form irregularities on the boundary surface, and can be applied to reduce the size of the chip-type ceramic electronic component. Since it has a method, it can be suitably used for multilayer electronic components, multilayer substrates, modules and the like.

An example of the defect / peeling state of the external electrode when the corner of the electronic component is an edge is shown. The adhesion state of the external electrode when the corner of the electronic component is rounded is shown. An example of the peeling state of the external electrode by miniaturization of an electronic component is shown. An example of the contact | adherence state of the external electrode and ceramic part of the laminated body of the ceramic green sheet of this invention is shown. An example of the contact | adherence state of the external electrode and ceramic part of the laminated body of the ceramic green sheet of this invention is shown. An example of the contact | adherence state of the external electrode and ceramic part of the laminated body of the ceramic green sheet of this invention is shown. The formation method of the layer which comprises a ceramic green sheet laminated body is shown. Another method for forming the layers constituting the ceramic green sheet laminate will be described.

Explanation of symbols

1: External electrode 2: Internal electrode 3: Insulator 4: Insulator 5: Conductor (external electrode)
6: Cutting margin 7: Ceramic green sheet 8, 12: Negative photosensitive insulator 9, 13: Positive photosensitive insulator (cutting margin)
10: Photomask 11, 14: Conductor (external electrode)

Claims (5)

A method for producing a multilayer electronic component comprising a laminate of ceramic green sheets,
The ceramic green sheet external terminal electrodes and the unnecessary area is patterned in the boundary of the electronic component of the ceramic region and the external terminal electrode regions, formed by photolithography a state of being inclined to the cross-sectional direction,
A method of manufacturing a multilayer electronic component, comprising: laminating and pressing ceramic green sheets on which the external terminal electrodes are patterned. The patterning of the external terminal electrode included in the ceramic green sheet is obtained by laminating a plurality of types of the ceramic green sheets.
The boundary between the external terminal electrode region and the unnecessary area are substantially spherical rounded shape,
2. The method for manufacturing a multilayer electronic component according to claim 1, wherein a boundary in a cross-sectional direction between the external terminal electrode region and the ceramic region is in an uneven state . At least the insulator, the conductor for internal electrodes, the conductor for external electrodes, and the disappearing material are patterned so that the portions that become the corners of the multilayer electronic component after being laminated have a substantially spherical round shape,
Furthermore, unevenness is formed at the boundary between the ceramic region of the multilayer electronic component and the external terminal electrode region, and is patterned by inclining in the cross-sectional direction,
The electronic component is formed around each of the regions constituting the multilayer electronic component, the laminated body of the ceramic green sheets being outside the substantially spherical round portion and continuously with the substantially spherical round portion. Forming a vanishing layer made of a material different from the material so as to penetrate the ceramic green sheet;
Laminating a plurality of ceramic green sheets and laminating so that the disappearing material is patterned through the thickness direction of the ceramic green sheet laminate; and
A method for producing a laminated electronic component comprising a step of erasing a region made of a disappearing material by a specific treatment and simultaneously separating the ceramic green sheet laminate into individual laminated electronic components without applying an external force. To claims 1 to 3 is formed by the manufacturing method of the multilayer electronic component according multilayer ceramic electronic component. A multilayer ceramic electronic component composed of a laminate of ceramic green sheets,
  A multilayer ceramic electronic component, wherein a plurality of irregularities having the same dimensions as the thickness of each of the laminated ceramic green sheets are formed at a boundary of the ceramic region and the external terminal electrode region in the laminated cross-sectional direction.

Images