Multilayer electronic device with improved connectivity, and method for manufacturing the same

Abstract

To provide a method for making a multilayer ceramic electronic device.SOLUTION: The method includes placing a screen printing 200 mask on a layer of support material, and printing a conductive pattern on the layer of support material using the screen printing mask. The conductive pattern includes a plurality of electrode shapes including respective central enlarged portions. The method also includes cutting the layer of support material and the conductive pattern along a plurality of cutting lines 130 intersecting a central enlarged section 202 of an opening 110 such that at least one of the electrode shapes is divided into a pair of electrodes along a cutting width. The cutting width is indicative of a cutting accuracy associated with at least one of the cutting lines.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of the filing date of U.S. Provisional Patent Application No. 62 / 575,626, filed on October 23, 2017, which is hereby incorporated by reference in its entirety.

[0002] The present subject matter generally relates to improved component formation for multilayer electronic components. More particularly, the present subject matter relates to a multilayer electronic device with improved connectivity between electrodes and terminals, and a method of making the same.

Background Art

[0003] Many modern electronic components are implemented as monolithic devices, which can include a single component or multiple components within a single chip package. A particular example of such a monolithic device is a multilayer capacitor or capacitor array, and of particular interest with respect to the disclosed technology are multilayer capacitors having interdigitated internal electrode layers and corresponding electrode tabs. Examples of multilayer capacitors incorporating features of interdigitated capacitor (IDC) technology can be found in U.S. Patent Nos. 4,831,494 (Arnold et al.), 5,880,925 (DuPre et al.), and 6,243,253 (B1) (DuPre et al.). Other monolithic electronic components correspond to devices that incorporate multiple passive components in a single chip structure. Such incorporated passive components can provide a selected combination of resistors, capacitors, inductors, and / or other passive components formed in a multilayer configuration and implemented as a monolithic electronic device.

[0004] In known exemplary assembly methods, multilayer capacitors are formed by providing individual sheets of ceramic dielectric cut from a pre-prepared length-extended ceramic material or tape of ceramic material. The individual sheets are silk screen printed with electrode ink through multiple sets of electrode patterns. The printed sheets are then stacked into multiple layers and often laminated into a solid layer called a pad. The pads can then be cut into individual multilayer components, and further processing of the multilayer components, such as sintering of the pads and terminating of the individual components, can be performed. Terminating of the components can include applying a metal paint to contact selected ones of the pre-screen printed electrodes and then separately firing to secure the metal paint termination material to the capacitor.

[0005] During manufacturing, after the pads are cut into individual components and before the terminations are formed, a non-conductive coating may be applied to the components to protect and / or electrically insulate the internal elements of the device (e.g., electrodes and dielectric layers). However, such a non-conductive coating may inadvertently coat the exposed portions of the electrodes configured to make electrical connection to the terminations once formed.

[0006] Also, the ever-shrinking size of electronic components can make it difficult to accurately cut the pads into individual multilayer components along a predetermined cut line. Misalignment of the cutting operation can result in defective components (e.g., having an electrical short between terminals) or low performance. The following components may be brought about. For example, misalignment in cutting alignment can disconnect some electrodes from the terminals. This can undesirably reduce the capacitance of a multilayer capacitor or increase the leakage current of a varistor. However, inspection of the cutting position of such multilayer components requires a destructive test. For example, since the electrode layer is hidden within the structure, determining the accuracy of the cutting operation requires polishing or otherwise removing a part of the component to visually inspect the internal structure. Such destructive tests are costly and inefficient.

Summary of the Invention

Problems to be Solved by the Invention

[0007] Therefore, a multilayer component with improved electrical connectivity and a method for manufacturing the same are welcomed in the industry.

Means for Solving the Problems

[0008] In view of the recognized features found in the prior art and addressed by the present subject matter, an improved multilayer electronic device and a method for manufacturing the same have been developed. According to an embodiment of the present invention, a method for manufacturing a multilayer electronic device is disclosed. The method can include placing a screen printing mask on a layer of a support material and printing a conductor pattern on the layer of the support material using the screen printing mask. The conductor pattern can include a plurality of electrode shapes each including a central enlarged portion. The method can include cutting the layer of the support material and the conductor pattern along a plurality of cutting lines that intersect the central enlarged portion such that at least one of the plurality of electrode shapes is divided into a pair of electrodes along a cutting width. The cutting width can indicate the cutting accuracy associated with at least one of the cutting lines.

[0009] According to another aspect of the present invention, a multilayer electronic device including a plurality of layers is disclosed. The plurality of layers can include electrodes, and at least one of the plurality of electrodes can include a main portion extending in the longitudinal direction. The main portion can have a main width in the transverse direction orthogonal to the longitudinal direction. At least one of the plurality of electrodes can include a base portion having a maximum base width greater than the main width. The base portion can have a longitudinal width profile, and at least a part of the width profile can be inclined at an angle greater than 0 degrees and less than 90 degrees with respect to the longitudinal direction.

[0010] Other features and aspects of the present invention are described in more detail below. A full and enabling disclosure of the present invention, including the best mode thereof, directed to those of ordinary skill in the art, is set forth herein, and this specification makes reference to the accompanying drawings below.

Brief Description of the Drawings

[0011]

Figure 1A

Figure 1B

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Figure 2C

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Figure 3

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Figure 4B

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Figure 5

DETAILED DESCRIPTION OF THE INVENTION

[0012] The repeated use of reference numerals throughout this specification and the accompanying drawings is intended to represent the same or similar features and elements of the present invention. This description is only an explanation of exemplary embodiments and is not intended to limit the broader aspects of the present invention, and it should be understood by those skilled in the art that the broader aspects are embodied in the exemplary structures.

[0013] Generally speaking, the present invention is directed to a multilayer electronic device with improved electrical connectivity and a method of fabricating the same. The multilayer electronic device can include a plurality of dielectric layers interposed between alternating electrode layers. The electrode layers can include electrodes formed using a screen printing and dicing process. The multilayer electronic device can be configured as a capacitor, resistor, varistor, inductor, and / or the like. Regardless of this configuration, the inventors have found that through control of the screen printing and dicing processes used to form the electrodes, it is possible to form a multilayer electronic device that not only has improved electrical connectivity between various electrodes and terminals, but also provides a simple and efficient method of inspecting the multilayer electronic device.

[0014] For example, in some embodiments, the electrode material can be screen printed onto a plurality of inter-electrode support layers so as to form the electrode shape thereon. The inter-electrode support layers may be stacked so as to form a stack of layers, and this stack can be cut along a cutting line so as to form individual multilayer electronic devices. However, accurately cutting the structure on the cutting line can be difficult, especially for devices with smaller case sizes. For example, as is known in the art, the case size of an electronic device can be represented as a four-digit code (e.g., 2520), where the first two digits are the length of the device in millimeters (or units of one thousandth of an inch), and the last two digits are the width of the device in millimeters (or units of one thousandth of an inch). For example, common metric case sizes can include 2012, 1608, 0603. However, accurately cutting a stack of layers called a "pad" to form a device with a smaller case size can be difficult as it involves a high degree of accuracy.

[0015] According to some embodiments of the present disclosure, a screen printing mask can be used to form an electrode shape on a layer of a support material. The screen printing mask can have an opening with a central enlarged section, resulting in an electrode shape that similarly has a central enlarged portion. By cutting the stack of layers through the central enlarged portion, the electrode shape can be cut into a pair of electrodes. Similarly, such a cut can expose a portion of the newly formed pair of electrodes along the end face of the pad. The exposed portion of the electrode can have an exposed width. According to an aspect of the present disclosure, as will be described in more detail below, the exposed width can indicate the cutting accuracy. Thus, by inspecting the exposed width at the end of the electrode, the cutting accuracy of the cutting operation can be easily determined, for example, without destructively modifying the pad to inspect the internal structure.

[0016] Also, in some embodiments, the electrode shape can have a central enlarged portion, as shown above. Such a central enlarged portion can cause the electrode to have a base width that is larger than the main width.

[0017] In some embodiments, the central enlarged portion can include a flat region having a longitudinal length. The length of the flat region can be selected based on the accuracy required or desired to cut the stack of layers. The required or desired accuracy may be necessary to achieve the desired performance characteristics or to meet quality goals and / or quality standards. Thus, by measuring the width of the exposed portion of the electrode and comparing it to the width of the flat region of the central enlarged portion, it can be determined whether the electrode was cut at a satisfactory location. For example, the flat region can have a longitudinal length (before cutting) that is less than about 400 micrometers (μm), less than about 200 μm in some embodiments, less than about 100 μm in some embodiments, less than about 50 μm in some embodiments, less than about 20 μm in some embodiments, less than about 10 μm in some embodiments, less than about 5 μm in some embodiments, and less than about 2 μm in some embodiments. The ratio of the total length of the longitudinal finished component to the length of the flat region (before cutting) can be greater than about 2.5, greater than about 5 in some embodiments, greater than about 10 in some embodiments, greater than about 20 in some embodiments, greater than about 50 in some embodiments, greater than about 100 in some embodiments, and greater than about 500 in some embodiments.

[0018] When the layer is cut to form individual components, the electrodes can each have a respective base portion, which can be approximately half of the central enlarged portion of the pre-cut electrode. The base portion includes a respective flat region having a longitudinal length of less than about 200 μm, in some embodiments less than about 50 μm, in some embodiments less than about 20 μm, in some embodiments less than about 10 μm, in some embodiments less than about 5 μm, and in some embodiments less than about 2 μm. The ratio of the total length of the completed longitudinal component to the length of the flat region of the base portion is greater than about 5, in some embodiments greater than about 10, in some embodiments greater than about 20, in some embodiments greater than about 50, in some embodiments greater than about 100, and in some embodiments greater than about 500.

[0019] In some embodiments, the central enlarged portion can include a sloped or curved portion. The sloped or curved portion can have a longitudinal length of less than about 200 μm, in some embodiments less than about 100 μm, in some embodiments less than about 50 μm, in some embodiments less than about 20 μm, in some embodiments less than about 10 μm, in some embodiments less than about 5 μm, and in some embodiments less than about 2 μm. The ratio of the total length of the completed longitudinal component to the length of the sloped or curved portion (before cutting) is greater than about 5, in some embodiments greater than about 10, in some embodiments greater than about 20, in some embodiments greater than about 50, in some embodiments greater than about 100, and in some embodiments greater than about 500.

[0020] In some embodiments, the sloped portion can have an inclination with respect to the longitudinal direction in the range from 0 to 90 degrees, in some embodiments in the range from about 5 to about 85 degrees, in some embodiments in the range from about 10 to about 80 degrees, in some embodiments in the range from about 20 to about 70 degrees, in some embodiments in the range from about 3 0 to about 60 degrees, for example, about 45 degrees.

[0021] The central enlarged portion can have a total longitudinal length of less than about 600 μm, less than about 400 μm in some embodiments, less than about 200 μm in some embodiments, less than about 100 μm in some embodiments, less than about 50 μm in some embodiments, less than about 20 μm in some embodiments, less than about 10 μm in some embodiments, less than about 5 μm in some embodiments, and less than about 2 μm in some embodiments (including, for example, the inclined portion and the flat region if present). The ratio of the total length of the longitudinal component to the total length of the central enlarged portion can be about 5 or more, about 10 or more in some embodiments, about 20 or more in some embodiments, about 50 or more in some embodiments, about 100 or more in some embodiments, and about 500 or more in some embodiments.

[0022] When the layer is cut to form individual components, the base portion of the electrode can have a longitudinal length that can be less than about 300 μm, less than about 200 μm in some embodiments, less than about 100 μm in some embodiments, less than about 50 μm in some embodiments, less than about 20 μm in some embodiments, less than about 10 μm in some embodiments, less than about 5 μm in some embodiments, and less than about 2 μm in some embodiments. The ratio of the total length of the longitudinal component to the length of the base portion can be about 5 or more, greater than about 10 in some embodiments, greater than about 20 in some embodiments, greater than about 50 in some embodiments, greater than about 100 in some embodiments, and greater than about 500 in some embodiments.

[0023] When formed on a multilayer device, the enlarged base width can provide electrical connectivity to the terminals. For example, in some embodiments, a non-conductive coating can be applied before the terminals are formed on the device. In some examples, a portion of the non-conductive coating can be deposited on the exposed portion of the electrode. However, the enlarged base width of the exposed portion can improve electrical connectivity and / or prevent electrical disconnection between the electrode and the terminal.

[0024] As shown above, the multilayer electronic device can be configured as a capacitor, resistor, varistor, inductor, and / or the like. Thus, the interelectrode support can be any suitable material for forming such a device. For example, to form a capacitor, the interelectrode support can be a dielectric material such as a ceramic material, semiconductor material, or insulating material, such as barium titanate, calcium titanate, zinc oxide, alumina with low-fire glass, or other suitable ceramic or glass bonding materials, but not limited thereto. Alternatively, the dielectric material can be an organic compound such as epoxy (with or without ceramic admixture, with or without glass fibers) that is popular as a circuit board material, or other plastics commonly used as dielectrics. In these cases, the conductor is usually a copper foil that is chemically etched to provide a pattern. In yet further embodiments, the dielectric material can be composed of a material having a relatively high dielectric constant (K) such as one of NPO (COG), X7R, X5R X7S, Z5U, Y5V, and strontium titanate. In one example, the dielectric material can have a dielectric constant in the range between about 2000 and about 4000.

[0025] To form the varistor, the interelectrode support can be a dielectric material such as, for example, barium titanate, zinc oxide, or any other suitable dielectric material. Various additives may be included in the dielectric material, for example, to create or enhance the voltage-dependent resistance of the dielectric material. For example, in some embodiments, the additives may include oxides of cobalt, bismuth, manganese , or combinations thereof. In some embodiments, the additives may include oxides of gallium, aluminum, antimony, chromium, titanium, lead, barium, nickel, vanadium, tin, or combinations thereof. The dielectric material can be doped with additives in the range of from about 0.5 mole percent to about 3 mole percent, and in some embodiments from about 1 mole percent to about 2 mole percent. The average particle size of the dielectric material can contribute to the non-linear characteristics of the dielectric material. In some embodiments, the average particle size can range from about 10 μm to 100 μm, and in some embodiments from about 20 μm to 80 μm.

[0026] The external terminal portion can be formed using any method generally known in the art. The external terminal portion can be formed using techniques such as sputtering, painting, printing, electroless plating, or fine copper termination (FCT), electroplating, plasma deposition, propellant spray / airbrush, etc.

[0027] In one embodiment, the external terminal portion can be formed such that the external terminal portion is relatively thick. For example, such a terminal portion can be formed by applying a thick film strip of metal to the exposed portion of the internal electrode layer. Such a metal can be a glass matrix and can include silver or copper. As an example, such a strip can be printed and fired onto the device. Thereafter, an additional plating layer of metal (e.g., nickel, tin, solder, etc.) can be formed over the terminal portion strip so that the device can be soldered to the substrate. Such application of the thick film strip can be performed using any method generally known in the art (e.g., a termination machine and a printing wheel for transferring a metal-containing paste onto the exposed internal electrode layer). An example of a component having an external terminal portion formed by a fired terminal portion and a metal film plated thereon is disclosed in U.S. Patent No. 5,021,921 to Sano et al., which is hereby incorporated by reference in its entirety.

[0028] The thick-plated external terminal portion can have an average thickness of about 150 μm or less, such as about 125 μm or less, such as about 100 μm or less, such as about 80 μm or less. The thick-plated external terminal portion can have an average thickness of about 25 μm or more, such as about 35 μm or more, such as about 50 μm or more, such as about 75 μm or more. For example, the thick-plated external terminal portion can have an average thickness from about 25 μm to about 150 μm, such as from about 35 μm to about 125 μm, such as from about 50 μm to about 100 μm.

[0029] In another embodiment, the external terminal portion can be formed such that the external terminal portion is a thin film plating of metal. Such a thin film plating can be formed by depositing a conductive material such as a conductive metal on the exposed portion of the internal electrode layer. For example, the leading edge of the internal electrode layer can be exposed so as to enable the formation of the plated terminal portion.

[0030] The thinly plated external terminal portion can have an average thickness of about 50 μm or less, for example, about 40 μm or less, for example, about 30 μm or less, for example, about 25 μm or less. The thinly plated external terminal portion can have an average thickness of about 5 μm or more, for example, about 10 μm or more, for example, about 15 μm or more. For example, the external terminal portion can have an average thickness from about 5 μm to about 50 μm, for example, from about 10 μm to about 40 μm, for example, from about 15 μm to about 30 μm, for example, from about 15 μm to about 25 μm.

[0031] Generally, the external terminal portion can be composed of plated terminal portions. For example, the external terminal portion can include an electroplated terminal portion, an electroless plated terminal portion, or a combination thereof. For example, the electroplated terminal portion can be formed by electroplating. The electroless plated terminal portion can be formed by electroless plating.

[0032] When a plurality of layers constitute the external terminal portion, the external terminal portion can include an electroplated terminal portion and an electroless plated terminal portion. For example, first, electroless plating can be used to deposit the material of the first layer. Then, the plating technique can be switched to an electrochemical plating system that can enable faster material accumulation.

[0033] When forming a plated terminal portion using any plating method, the leading edge of the lead tab of the internal electrode layer exposed from the body of the device is subjected to the plating solution. By exposing it, in one embodiment, the device can be immersed in the plating solution.

[0034] The plating solution contains a conductive material such as a conductive metal and is used to form the plated terminal portion. Such a conductive material can be any of the aforementioned materials or any generally known in the art. For example, the plating solution can be a nickel sulfamate bath solution or other nickel solution such that the plated layer and the external terminal portion are composed of nickel. Alternatively, the plating solution can be a copper acid bath or other suitable copper solution such that the plated layer and the external terminal portion are composed of copper.

[0035] Furthermore, it should be understood that the plating solution may contain other additives as generally known in the art. For example, the additives can include other organic additives and a medium that can assist in the plating process. Further, additives may be used to use the plating solution at a desired pH. In one embodiment, a resistance reduction additive can be used in the solution to assist in complete plating coverage and bonding of the plating material to the exposed leading edges of the device and the lead tabs.

[0036] The device can be exposed, submerged, or immersed in the plating solution for a predetermined time. Such an exposure time is not necessarily limited but can be for a time sufficient to allow sufficient plating material to deposit to form the plated terminal portion. In this regard, the time should be sufficient to allow for the formation of continuous connections among the desired exposed adjacent leading edges of the lead tabs of each internal electrode layer within an alternating set of dielectric layers and internal electrode layers.

[0037] Generally, the difference between electroplating and electroless plating is that electroplating uses an electrical bias, such as by using an external power source. Typically, an electroplating solution can be subjected to a high current density range, for example, 10 - 15 amperes per square foot (evaluated at 9.4 volts). The connections can be formed with a negative connection to the device that requires the formation of a plated terminal portion and a positive connection to a solid material (e.g., Cu in a Cu plating solution) in the same plating solution. That is, the device is biased to the opposite polarity of the plating solution's polarity. Using such a method, the conductive material of the plating solution is attached to the metal of the exposed leading edge of the lead tab of the internal electrode layer.

[0038] Prior to immersing or exposing the device in the plating solution, various pretreatment steps may be used. Such steps can be performed for various purposes, such as to catalyze, accelerate, and / or improve the adhesion of the plating material to the leading edge of the lead tab.

[0039] Furthermore, an initial cleaning step can be used prior to the plating step or any other pretreatment step. Such a step can be used to remove the accumulation of any oxides formed on the exposed lead tabs of the internal electrode layer. This cleaning step can be particularly useful in removing the accumulation of nickel oxides when the internal electrodes or other conductive elements are formed of nickel. Component cleaning can be performed by completely immersing in a pre - cleaning bath, such as a pre - cleaning bath containing an acid cleaner. In one embodiment, the exposure can be for a predetermined time, such as about 10 minutes. Alternatively, the cleaning can also be performed by a chemical polishing step or a harperizing step. In addition, the step of activating the exposed metallic leading edge of the exposed portion of the internal electrode layer can be performed to facilitate the deposition of the conductive material. Activation can be with a palladium salt, a photopatterned palladium organometallic precursor (by mask or laser), a screen print

[0040] It can be achieved by immersing in a brushed or inkjet - deposited palladium compound or an electrophoretic palladium deposit. It should be understood that the activation with palladium is currently disclosed as just one example of an activation solution that often works well for the activation of exposed portions formed of nickel or its alloys. However, it should be understood that it is also possible to utilize other activation solutions.

[0041] Also, instead of or in addition to the aforementioned activation step, when forming the internal electrode layer of the device, an activation dopant can be introduced into the conductive material. For example, when the internal electrode layer contains nickel and the activation dopant contains palladium, the palladium dopant can be introduced into the nickel ink or composition forming the internal electrode layer. By doing so, the palladium activation step can be eliminated. It should be further understood that some of the above - mentioned activation methods, such as organometallic precursors, also serve for the eutectic of glass - forming agents to increase the adhesion of the device to the generally ceramic body. When the activation step is taken as described above, traces of the activator substance can often remain on the conductive portions exposed before and after the plating of the terminal portion.

[0042] Furthermore, a post - treatment step after plating can also be performed. Such steps can be carried out for various purposes such as strengthening and / or improving the adhesion of the material. For example, a heating (or annealing) step can be used after performing the plating step. Such heating can be carried out by firing, laser subjection, UV exposure, microwave exposure, arc welding, etc.

[0043] As shown in this specification, the external terminal portion includes at least one plating layer. In one embodiment, the external terminal portion can include only one plating layer. However, it should be understood that the external terminal portion can include a plurality of plating layers. For example, the external terminal portion can include a first plating layer and a second plating layer. In addition, the external terminal portion can also include a third plating layer. The materials of these plating layers can be any of those described above and those generally known in the art.

[0044] For example, one plating layer such as the first plating layer can be composed of copper or its alloy. Another plating layer such as the second plating layer can be composed of nickel or its alloy. Another plating layer such as the third plating layer can include combinations such as tin, lead, gold, or alloys. Alternatively, the first plating layer can be composed of nickel, and subsequently the plating layer can be made of tin or gold. In another embodiment, a first plating layer of copper may be formed, and then a nickel layer may be formed.

[0045] In one embodiment, the first or the first plating layer can be a conductive metal (e.g., copper). Then, this area can be covered with a second layer containing a resistor-polymeric material for sealing. Then, this area can be polished to selectively remove the resistive polymer material and then replated with a third layer containing a conductive metal material (e.g., copper).

[0046] The aforementioned second layer above the initial plating layer may correspond to a solder barrier layer, such as a nickel - solder barrier layer. In some embodiments, the aforementioned layer may be formed by electroplating an additional layer of metal (such as nickel) on top of the first electroless or electrolytically plated layer (such as plated copper). Other exemplary materials for the layer and for the aforementioned solder barrier layer include nickel - phosphorus, gold, and silver. In some embodiments, the third layer on the aforementioned solder barrier layer may correspond to a conductive layer such as plated Ni, Ni / Cr, Ag, Pd, Sn, Pb / Sn or other suitable plated solder.

[0047] In addition, a layer of metal plating can be formed, followed by an electroplating step that can provide an electroless Ni - P alloy on such metal plating, for example, a resistive alloy or a higher - resistance metal alloy coating. However, it should be understood that any metal coating as would be understood by one of ordinary skill in the art from the complete disclosure herein can be included.

[0048] Any of the aforementioned steps can occur as a bulk process, such as barrier plating, fluidized bed plating, and / or a flow - through plating termination process, all of which are generally known in the art. Such bulk processes allow multiple components to be processed at once, providing an efficient and rapid termination process. This is a particular advantage over conventional termination methods such as the printing of thick - film terminal portions that require individual component processing.

[0049] As described herein, the formation of the external terminal portion is generally guided by the position of the exposed leading edge of the lead tab of the internal electrode layer. Such a phenomenon can be called "self - determination" since the formation of the external plated terminal portion is determined by the exposed conductive metal configuration of the internal electrode layer at the selected peripheral location of the device.

[0050] Further aspects of the above-described technique for forming a thin-film plated terminal portion are described in Ritter et al.'s U.S. Pat. Nos. 7,177,137 and 7,463,474, which are hereby incorporated by reference in their entirety. It should be understood that additional techniques for forming device terminal portions may also be within the scope of this technology. Exemplary alternatives include, but are not limited to, forming the terminal portion by plating, magnetism, masking, electrophoresis / electrostatics, sputtering, vacuum deposition, printing, or other techniques for forming both conductive layers of thick or thin films.

[0051] The multilayer electronic device can be within a predetermined size range. For example, in some embodiments, the device can have an overall length (e.g., in the X direction) in the range from about 0.1 mm or less to about 10 mm, in some embodiments from about 0.5 mm to about 5 mm, and in some embodiments from about 1 mm to about 4 mm. The device can have an overall width (e.g., in the Y direction) in the range from about 0.05 mm to about 3 mm, in some embodiments from about 0.2 mm to about 2 mm, and in some embodiments from about 0.5 mm to about 1.5 mm.

[0052] Next, referring to the drawings, FIGS. 1A and 1B show the first part of a sequence of steps that can be employed in the production of one embodiment of a multilayer electronic device according to the present subject matter. As shown in FIG. 1A, the first screen-printing mask 100 can comprise a plurality of openings. Three openings 110, 112, 114 are shown in FIG. 1A for simplicity. However, it should be understood that the screen-printing mask 100 can be larger than three openings. In some embodiments, each opening can generally have the same size and shape.

[0053] Throughout the following description of the various screen printing masks, note that while the mask portions are illustrated as distinct elements, other portions are hidden. In both examples, the screen is open to allow the passage of the printing material, as would be understood by one of ordinary skill in the screen printing art. Rather, shading is used merely for illustrative purposes to draw particular attention to those areas. For example, typically, those areas may correspond to electrodes within the finished product.

[0054] Referring further to FIG. 1A, according to aspects of the present disclosure, electrodes are printed on a plurality of continuously stacked layers. Four consecutive electrode layers 120-126 are shown in FIG. 1A for simplicity. The electrode layers 120-126 are formed on an inter-electrode support that is omitted from FIG. 1A for clarity. In some embodiments, the layer of the inter-electrode support may be composed of, for example, a dielectric material. The electrode material may be printed on the support layer using a screen printing mask 100. For example, the screen printing mask 100 may be disposed on a first layer of the inter-electrode material. The first layer 120 of the electrode material may be printed on the first layer of the inter-electrode material through a plurality of openings 110, 112, 114 in the screen printing mask 100 to form a first conductor pattern. During this step, the screen printing mask 100 can be shifted a predetermined distance to the right as seen in FIG. 1A. After printing the first layer 120, a second layer of the inter-electrode material can be disposed or deposited on top of the first layer. Next, the screen printing mask 100 is disposed on the second layer of the inter-electrode material and can be used to print a second layer 122 of the electrode material to form a second conductor pattern. This process can be repeated for subsequent layers, such as a third layer 124, a fourth layer 126, and so on. After the desired number of layers are formed, the stack of the inter-electrode material and the printed conductor patterns can be cut to form individual multi-layer devices 128 as described below.

[0055] It should be clearly understood that the examples in this specification regarding the total of four printed layers are merely examples. In an actual product, more or fewer layers may be provided to produce components that meet the desired electrical and physical characteristics. In some embodiments, a screen printing mask having other patterns and / or shapes may be used, as needed, to form other conductor patterns. The conductor patterns described in this specification are merely examples.

[0056] Referring further to FIGS. 1A - 1B, after the layers of the multilayer device are printed, the individual devices 128 can be cut from the stack of layers along a plurality of cutting lines 130, 132, 134. For example, the first multilayer device 128 may be formed between cutting lines 130 and 132, and the second multilayer device 128 may be formed between cutting lines 132 and 134, etc.

[0057] Referring to FIGS. 2A and 2A’, in some embodiments, the screen printing mask 100 can be arranged, for example, to form a shield electrode or a dummy electrode 128. Various configurations of the layers may be formed according to the desired characteristics of the multilayer device. After printing of the various layers 120 - 126, as described above with reference to FIGS. 1A, 1B, 2A, and 2A’, the individual devices 128 may be fired using processes well known to those skilled in the art.

[0058] Referring to FIGS. 2B - 2D, after stacking and printing, the pads may be cut to the individual devices 150. For example, referring to FIG. 2C, the electrodes can have exposed portions 144, 146 along the opposing face ends 154, 156 of the device 150. As will be described in more detail below, the exposed portions 144, 146 can have an exposed width indicating the accuracy of the cutting operation.

[0059] Before the terminal portions 160, 162, 164 are formed on the device 150 after the initial firing, a non-conductive coating may be applied. For example, in some embodiments, the terminal portions 160, 162, 164 may be formed by applying a terminal portion material to the end faces 154, 156. In some embodiments, the terminal portion material can also be applied to the exposed areas 140, 142 of the upper electrode, which can be the shield electrode or the dummy electrode 128. The terminal portions 160, 162 can be electrically connected to the exposed end faces 144, 146 of the electrodes. In some embodiments, the terminal portion portions 162 and 164 can also continuously cover the uppermost electrode portion 142 of the device 150 and the exposed electrode portions at the respective end faces 154, 156, respectively.

[0060] Referring next to FIG. 3, individual screen prints 200 are shown in accordance with aspects of the present disclosure. The screen print 200 can have a plurality of openings 110, 112 that can be used for an electrode material printed on a layer of inter-electrode material, for example, as described above, to form a multi-layer device. At least one of the plurality of openings can have a central enlarged section 202. For example, in some embodiments, the central enlarged section 202 can be located in the middle of the opening 110 along the length of the opening in the longitudinal direction 204. For example, the cut line 130 can intersect the central enlarged section 202 of the opening 110.

[0061] Referring to FIG. 4A, in some embodiments, as described above, the opening 100 can be shaped such that, for example, during a printing process, the opening 100 forms an electrode shape 300 on a layer of interelectrode material. The electrode shape 300 can have a central enlarged portion 301 as a result of a central enlarged section 202 of the opening 110 of the screen printing mask 100. The electrode shape 300 can have a main portion 302 extending in the longitudinal direction 204, and the main portion 302 can have a main width 304 in a transverse direction 306 orthogonal to the longitudinal direction 204. The central enlarged portion 301 can extend beyond the main width 304 in the transverse direction. For example, the electrode shape 300 can have a base portion 308 having a maximum base width 310 that is greater than the main width 304. The base portion 308 can have a width profile in the longitudinal direction 204. The width profile defines the shape of the central enlarged portion 301 and / or the base portion 308 relative to the main width 304 of the main portion 302.

[0062] As shown above, in some embodiments, the electrode shape 300 can be cut into a pair of electrodes along a cut line 130. In some embodiments, the cut line 130 can extend generally along the transverse centerline of each electrode shape 300 in the longitudinal direction 204. FIG. 4B shows a width profile 318 of an embodiment of the central enlarged portion 301 of the electrode shape 300 before the electrode shape 300 is cut into a pair of electrodes. The width profile 318 can be defined as the distance in the transverse direction 306 by which the central enlarged portion 301 (or the base portion 308) extends beyond the main width 304 of the main portion 302. As will be described in more detail below, at least a portion of the width profile can be inclined at an angle greater than 0 degrees and less than 90 degrees with respect to the longitudinal direction.

[0063] Referring to FIG. 4B, as described above, in some examples, the electrode shape 300 can be cut along an actual cut position 320 that can vary from the desired position of the cut line 130. In some embodiments, the central enlarged portion 301 can include a flat region 314 located at the center of the central enlarged portion 301. The flat region 314 can have a length in the longitudinal direction 204 (also indicated by the parentheses 314). (For example, to achieve desired performance characteristics or meet quality goals and / or quality standards), the length of the flat region can be selected based on the accuracy required to cut the stack of layers. In some embodiments, the inclined or curved portion 316 can be disposed on either side of the flat region. The inclined or curved portion 316 can have a length in the longitudinal direction 204 (also represented by the parentheses 316). Thus, the central enlarged portion can have the length of the flat region 314 (if present), and the longitudinal length including the inclined or curved portion 316.

[0064] Due to the difficulty associated with cutting exactly along the cut line 130, the actual cut position 320 can intersect the inclined or curved portion 316 instead of being perfectly aligned with the desired position of the cut line 130. As a result, for example, as shown in FIG. 4A, the ends of a pair of electrodes formed along the face edge of the device during cutting can have an exposed width 322. In some examples, only the ends of the electrode pair can be visible when the layer pads are printed, stacked, and cut into individual components. Thus, measuring the exposed width 322 can be a useful way to determine the cutting accuracy associated with the cutting operation. In some embodiments, the cutting accuracy can be defined as the longitudinal distance between the actual cut position 320 and the desired position of the cut line 130. In other words, the central enlarged portion 301 can be shaped such that the exposed width 322 can indicate the cutting accuracy. For example, the width profile 318 can have a known shape such that the exposed width 322 can be correlated with the width profile 318 to determine the cutting accuracy.

[0065] Referring further to FIG. 4B, the inclined or curved portion 316 can be inclined at an angle 324 greater than 0 degrees and less than 90 degrees with respect to the vertical direction. For example, in some embodiments, as shown in FIG. 4B for example, the inclined or curved portion 316 may have a straight edge with a consistent inclination along its length.

[0066] In some embodiments, the flat region 314 of the central enlarged portion 301 can have the maximum base width 310 of the electrode shape 300. The length of the flat region 314 in the vertical direction 204 can correspond to an acceptable deviation of the actual position of the cutting line 130 from the desired position of the cutting line 130. Thus, when the electrode shape 300 is cut into a pair of electrodes, if the exposed width 322 is smaller than the maximum base width 310, it can be easily determined that the stack has been cut along the cutting line 310 outside the acceptable cutting region.

[0067] Referring to FIGS. 4C and 4D, in some embodiments, as shown in FIG. 4C for example, the curved portion 316 can be arcuate in a concave shape. In some embodiments, as shown in FIG. 4D for example, the central enlarged portion 301 can be arcuate in a convex shape. Referring to FIG. 4E, in some embodiments, the central enlarged portion 301 may not include the flat region 314 at all. Instead, the inclined portion 316 may form a pointed tip. In some embodiments, this pointed tip can be aligned with the desired cutting position for the cutting line 130. Referring to FIG. 4F, in some embodiments, the central enlarged portion 301 can include a single curved portion 316 having, for example, a semi-circular shape or an elliptical shape.

[0068] Referring to FIG. 5, aspects of the present disclosure are directed to a method 500 for fabricating a multilayer electronic device. Generally, method 500 is described herein with reference to the screen printing mask 100 and the electrode pattern 300 described above with reference to FIGS. 1-4. However, it should be understood that the method 500 of the present disclosure can be implemented using any suitable screen printing mask and electrode pattern to form any suitable multilayer device, including, for example, any suitable type of capacitor, varistor, inductor, and device array. Additionally, although FIG. 5 shows steps performed in a particular order for purposes of illustration and description, the methods described herein are not limited to any particular order or configuration. Those skilled in the art using the disclosure provided herein will understand that the various steps of the methods disclosed herein can be omitted, rearranged, combined, and / or adapted in various ways without departing from the scope of the present disclosure.

[0069] Referring to FIG. 5, method 500 can include, at (502), disposing a screen printing mask 100 on a layer of a support material. For example, the screen printing mask 100 may be disposed by an automated process as known in the art.

[0070] Method 500 can include, at (504), printing a conductor pattern on a layer of a support using a screen printing mask 100. The conductor pattern can include a plurality of electrode shapes 300 each having a central enlarged portion 301. For example, in some embodiments, the step of printing the conductor pattern can include applying an electrode material through a plurality of openings 110 in the screen printing mask, and the plurality of openings 100 can each include a respective central enlarged section 202 so as to form the central enlarged portions 301 of the plurality of electrode shapes 300. In some embodiments, the step of printing the conductor pattern can include forming the central enlarged portions 301 of the plurality of electrode shapes 300 such that the central enlarged portions 301 include respective edges that are inclined at an angle greater than 0 degrees and less than 90 degrees with respect to the longitudinal direction 204 toward a transverse centerline of at least one of the plurality of electrode shapes.

[0071] Method 500 can include, at (506), cutting the layer of the support and the conductor pattern along a plurality of cutting lines 130. In some embodiments, the cutting lines 130 can intersect the central enlarged portions 301 such that at least one of the plurality of electrode shapes 300 is split into a pair of electrodes. One or more of the resulting pair of electrodes can have an exposed width 322 indicative of a cutting accuracy.

[0072] In some embodiments, the method can also include determining a cutting accuracy based on the cutting width 322 of at least one of the plurality of electrode shapes 300. The cutting accuracy for a given cutting line 130 can be defined as a longitudinal offset between the actual position 320 of the cutting line 130 and the desired cutting position of the cutting line 130. In some embodiments, the step of determining the cutting accuracy can include referring to a known width profile 318 that relates the cutting width 322 to the longitudinal offset between at least one of the cutting lines 130 and the desired cutting position.

[0073] In some embodiments, method 500 can also include applying a non-conductive coating to a multilayer electronic device. The non-conductive coating can be applied to less than the entirety of the exposed portion (e.g., along less than the entire exposed width of a pair of electrodes). In some embodiments, method 500 can also include forming a first terminal electrically connected to one of a pair of electrodes and a second terminal electrically connected to the other of the pair of electrodes formed by cutting the electrode shape 300 along the cut line 130.

[0074] While the subject matter has been described in detail with respect to its specific embodiments, those skilled in the art will understand, upon understanding the foregoing, that alternatives, modifications, and equivalents of such embodiments can be readily made. Accordingly, the scope of the present disclosure is by way of example and not by way of limitation, and the present disclosure does not exclude including such modifications, variations, and / or additions to the subject matter as would be readily understood by those skilled in the art.

Claims

Claim 1 A method of fabricating a multilayer electronic device, comprising: placing a screen printing mask on a layer of a support material; printing a conductor pattern including a plurality of electrode shapes each including a central enlarged portion on the layer of the support material using the screen printing mask, wherein each of the central enlarged portions includes respective edges inclined at an angle greater than 0 degrees and less than 90 degrees with respect to the vertical direction toward the center line of at least one of the plurality of electrode shapes; cutting the layer of the support material and the conductor pattern along a plurality of cutting lines intersecting the central enlarged portion such that at least one of the plurality of electrode shapes is divided into a pair of electrodes along a cutting width, wherein the cutting width of at least one of the plurality of electrode shapes indicates a cutting accuracy associated with at least one of the cutting lines; cutting the layer of the support material and the conductor pattern along the vertical cutting line, wherein each of the edges in the cutting width has a distance in a lateral direction perpendicular to the vertical direction from the vertical cutting line; wherein the central enlarged portion includes a flat region extending parallel to the vertical direction, and the length of the flat region in the vertical direction corresponds to an allowable deviation of the actual position of the cutting line from a desired position of the cutting line. Claim 2 The method according to claim 1, wherein the step of printing the conductor pattern includes applying an electrode material through a plurality of openings in the screen printing mask, and the plurality of openings each include a respective central enlarged section. Claim 3 The step of printing the conductor pattern includes forming the plurality of electrode shapes such that each of the plurality of electrode shapes has a respective length extending in the vertical direction; The step of cutting the layer of the support material and the conductor pattern includes cutting along the plurality of cutting lines extending substantially in a lateral direction perpendicular to the vertical direction; The method according to claim 1. Claim 4 The method according to claim 1, further comprising measuring the cutting width of at least one of the plurality of electrode shapes. Claim 5 The method according to claim 4, further comprising the step of determining the cutting accuracy based on the at least one cutting width among the plurality of electrode shapes, wherein the cutting accuracy is a vertical offset between at least one of the cutting lines and a desired cutting position.

6. The method according to claim 5, wherein the step of determining the cutting accuracy includes referring to a width profile that relates the cutting width to the vertical offset between at least one of the cutting lines and the desired cutting position.

7. The method according to claim 1, wherein each of the edges slopes from the main portion towards the flat region towards the center line of at least one of the plurality of electrode shapes.

8. The method according to claim 1, wherein each of the edges forms a pointed tip at the center line.

9. The method according to claim 1, wherein the step of cutting the layer of the support material along the plurality of cutting lines includes cutting at least one of the plurality of electrode shapes substantially along the lateral center line of the central enlarged portion.

10. The method according to claim 1, further comprising the step of applying a non-conductive coating to the multilayer electronic device with less than all of the exposed portions of the pair of electrodes.

11. The method according to claim 1, further comprising the step of forming a first terminal electrically connected to one of the pair of electrodes and a second terminal electrically connected to the other of the pair of electrodes.

12. A multilayer electronic device comprising a plurality of layers, the plurality of layers comprising a plurality of electrodes, at least one of the plurality of electrodes having a main portion extending in a longitudinal direction and having a main width in a lateral direction orthogonal to the longitudinal direction, a base portion having a width profile in the longitudinal direction from the main portion of each layer of the plurality of layers including at least one of the plurality of electrodes to a lateral edge, the lateral edge extending in the lateral direction, the width of the base portion at any position along the width profile being greater than the width of the main portion, and at least a part of the width profile being inclined at one or more angles with respect to the longitudinal direction, the one or more angles being greater than 0 degrees and less than 90 degrees, the base portion, The width profile has a lateral distance in the lateral direction from the longitudinal edge of each layer extending in the longitudinal direction, The width profile includes a flat region extending parallel to the longitudinal direction, and the longitudinal length of the flat region corresponds to an acceptable deviation of the actual position with respect to the desired position of a cutting line that cuts at least one of the plurality of electrodes from a layer of a support material on which a conductor pattern is printed, multilayer electronic device.

13. The flat region of the width profile has a maximum base width that is greater than the main width and is located adjacent to an end of at least one of the plurality of electrodes, the multilayer electronic device according to claim 12.

14. The flat region has a longitudinal length that is less than 200 μm, the multilayer electronic device according to claim 12.

15. The flat region has a length in the longitudinal direction, the multilayer electronic device has a total length in the longitudinal direction, and the ratio of the length of the total length of the multilayer electronic device to the length of the flat region is greater than about 5, the multilayer electronic device according to claim 12.

16. The base portion has a longitudinal length that is less than about 300 μm, the multilayer electronic device according to claim 12.

17. The multilayer electronic device has a total length in the longitudinal direction, the base portion has a length in the longitudinal direction, and the ratio of the length of the total length of the multilayer electronic device to the length of the base portion is greater than about 5, the multilayer electronic device according to claim 12.

18. The part of the width profile that is inclined has a longitudinal length that is less than about 200 μm, the multilayer electronic device according to claim 12.

19. The one or more angles are inclined from the main portion towards the lateral edge, the multilayer electronic device according to claim 12.

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