JP2010251630A - Information recording element, information recording apparatus, and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information recording member that is formed with a simply structured printing method. <P>SOLUTION: An information recording apparatus includes: a substrate 102; one or more lower wirings 103 provided on the substrate; a plurality of conductive bumps 104 provided on the lower wirings by printing; an insulating layer 105 provided to cover the substrate, the lower wirings and the conductive bumps; and one or more upper wirings 106 provided on the insulating layer to be overlapped with the conductive bumps across the lower wirings. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an information recording apparatus capable of electrically recording information and a manufacturing method thereof.

  In recent years, from the viewpoints of flexibility, weight reduction, cost reduction, etc., attempts to manufacture electronic devices by printing methods are active, and application to driving circuits such as organic EL and electronic paper and electronic tags is expected. Yes. Some electronic devices require information recording. For example, information for identifying a solid is recorded in an electronic tag.

  As an example of manufacturing an information recording element using a coating method, an organic ferroelectric memory in which a soluble ferroelectric polymer material is formed between electrodes has been studied (Patent Document 1). This organic ferroelectric memory is writable, but requires special materials and processes and is not easy to manufacture.

  Further, there are a fuse ROM, an antifuse ROM, and the like as nonvolatile information recording elements for recording information according to the conduction state of a circuit. The fuse ROM is made nonconductive by cutting a circuit with a laser or the like with respect to an element in a conductive state, and recording is performed. However, the fuse ROM requires a device such as a laser for non-conduction, and it is difficult to write on many unspecified solids such as an electronic tag. On the other hand, the antifuse ROM conducts and records an insulated circuit, and can easily conduct writing by causing dielectric breakdown in the insulating layer by applying a voltage. However, these elements are all formed by a vacuum film forming method using an inorganic material for the insulating layer, and can not be manufactured by a manufacturing method that does not use a vacuum device, such as a coating method or a laminating method. It was unsuitable for flexibility, weight reduction, and cost reduction.

JP 2006-253295 A JP 2008-258598 A JP 2008-52789 A

  In view of the above problems, an object of the present invention is to provide an information recording element and an information recording apparatus that can be easily manufactured with a simple structure.

As means for solving the above-mentioned problems, the invention according to claim 1 of the present invention includes a substrate, a lower electrode provided on the substrate, a conductive bump provided on the lower electrode, An information recording element comprising: an insulating layer provided so as to cover the conductive bump; and an upper electrode provided on the insulating layer and immediately above the conductive bump.
The invention according to claim 2 is the information recording element according to claim 1, wherein the bump contains conductive fine particles.
The invention according to claim 3 is the information recording element according to claim 2, wherein the conductive fine particles have an average particle diameter of 1 μm to 5 μm.
The invention according to claim 4 is characterized in that the 10-point average surface roughness Rz of the conductive bump is in the range of 0.5 μm to 5 μm. It is.
A fifth aspect of the present invention is an information recording apparatus including the information recording element according to any one of the first to fourth aspects.
The invention according to claim 6 has a plurality of upper wirings and a plurality of lower wirings intersecting with the upper wirings, and any one of claims 1 to 4 at a location where the upper wiring and the lower wiring intersect. The information recording device described above is connected to the information recording device.
The invention according to claim 7 is a step of forming a lower wiring on the substrate, a step of forming a conductive bump on the lower wiring, and a step of forming an insulating layer on the substrate so as to cover the conductive bump. And a step of forming the upper wiring so as to be directly above the conductive bump on the insulating layer.
The invention according to claim 8 is the method for manufacturing an information recording apparatus according to claim 7, wherein the insulating layer is formed by a coating method.
The invention according to claim 9 is the method of manufacturing an information recording apparatus according to claim 7, wherein the insulating layer is formed by heat-pressing a film-like hot melt adhesive.
The invention according to claim 10 is characterized in that the conductive bump is formed by screen printing a paste containing conductive fine particles. Is the method.

  According to the present invention, an information recording element can be realized with a simple structure using conductive bumps, and an information recording apparatus can be easily manufactured by using a coating method such as a printing method or a laminating method. It has become possible.

It is a top view of the information recording device concerning an embodiment of the invention. It is sectional drawing between AB of FIG.

  Embodiments of the present invention will be described with reference to the drawings. However, the drawings are schematic views, and the scale and configuration of each member are arbitrary as long as the effects of the invention are exhibited.

  A plan view of the information recording apparatus 100 of the present invention is shown in FIG. FIG. 2 is a cross-sectional view taken along the line AB in FIG. The information recording apparatus 100 of the present invention is composed of an array of information recording elements. The information recording element of the present invention includes a lower electrode 103 provided on a substrate 102, and conductive bumps 104 provided on the lower electrode 103. And an insulating layer 105 provided on the substrate 102 so as to cover the conductive bump 104, and an upper electrode 106 provided on the insulating layer 105 and immediately above the conductive bump 104. As shown in FIG. 1, the lower electrode 103 and the upper electrode 106 constitute a lower wiring 103 and an upper wiring 106 that are simultaneously connected to other elements or circuits. Alternatively, wirings and electrode patterns may be provided separately. That is, each information recording element may include a lower electrode provided connected to the lower wiring 103 and an upper electrode provided connected to the upper wiring 106.

  In the example of the information recording apparatus 100 in FIG. 1, an array of a plurality of information recording elements is formed, and each information recording element is provided on the insulating layer 105 so as to intersect the lower wiring 103 and overlap the conductive bump 104. The upper wiring 106 is provided. The information recording apparatus of FIG. 1 has two lower wirings, two upper wirings, and information recording elements provided at four points where the lower wiring and the upper wiring intersect (4 bits), but this is not the only case. Absent. The number can be provided according to the required recording capacity.

  Information is written by applying a voltage (write voltage) between the selected one lower wiring 103 and upper wiring 106, so that the information recording element connected to the selected lower wiring 104 and the upper wiring 106 has a write operation. The dielectric breakdown is caused in the insulating layer portion between the conductive bump 104 and the upper electrode, and the selected lower wiring 104 and the upper wiring 6 are made conductive. That is, information is recorded as the presence / absence of conduction between the lower electrode and the upper electrode of the information recording element at a predetermined position.

  For example, information is read by applying a voltage between the lower electrode and the upper electrode of the information recording element at a predetermined position to determine whether or not there is conduction, by applying a voltage that does not cause dielectric breakdown in the conductive bump 104 portion below the write voltage. .

  Note that the configuration and writing / reading method of the information recording apparatus 100 are not limited to those described above, and the configuration and method of a conventionally known antifuse-type information recording apparatus can be applied as appropriate. For example, as described in Patent Document 2, a diode or a transistor for stabilizing the write voltage may be incorporated.

  The applied voltage that causes dielectric breakdown needs to be small to some extent. The voltage at which dielectric breakdown occurs depends on the surface shape of the conductive bump 104 and the thickness of the insulating layer 105 on the conductive bump. When the bump surface has moderate unevenness, the electric field concentrates on the bump protrusion, whereby the voltage at which dielectric breakdown occurs is reduced, and the region where dielectric breakdown occurs on the insulating layer can be limited. Further, the thinner the insulating layer on the bump, the smaller the voltage at which dielectric breakdown occurs.

  The surface shape of the conductive bump 104 is preferably such that the 10-point average roughness Rz is between 0.5 μm and 5 μm. The 10-point average roughness Rz is defined by JIS B0601-1994. When Rz is smaller than 0.5 μm, the effect of the electric field concentration cannot be sufficiently obtained. On the other hand, if it is larger than 5 μm, a short circuit between the lower electrode and the upper electrode becomes a problem before the write voltage is applied.

  The conductive bump 104 having surface irregularities can be formed by a printing method using a material containing conductive fine particles. Various known methods can be used as the printing method, but screen printing and intaglio printing suitable for thick film printing are preferable. As the conductive fine particles, various known materials such as Ag, Cu, and Ni metal powders can be used.

  The conductive fine particles preferably include particles having an average particle diameter of 1 μm to 5 μm. When the average particle size is only 1 μm or less, the necessary unevenness cannot be formed on the bump surface. On the other hand, when the thickness is only 5 μm or more, there is a possibility that problems such as a decrease in the resolution of the bumps and clogging of the screen plate may occur during bump printing.

  The substrate 102 can be appropriately selected from various known materials such as soda lime glass, quartz, polyethylene terephthalate (PET), and polyethylene naphthalate (PEN) in consideration of heat resistance.

  The materials used for the various wirings (upper wiring 103 and lower wiring 106) of the present invention are, for example, metals such as Al, Cr, Au, Ag, Ni, and Cu, transparent conductive films such as ITO, and poly (ethylenedioxythiophene). / Use of conductive polymer such as polystyrene sulfonate (PEDOT / PSS) and polyaniline, solution in which metal colloidal particles such as Au, Ag, Ni and Cu are dispersed, paste using metal particles such as Ag as a conductive material, etc. be able to. As a method for forming various electrodes, for example, a dry process such as a vacuum deposition method or a sputtering method, or a printing method such as a screen printing method, a reverse offset printing method, a flexographic printing method, or an ink jet method can be used.

The insulating layer 105 can be formed by various coating methods such as spin coating, dip coating, and flexographic printing. Material used is capable of any of various _known inorganic material such as _{SiO 2, Ba x Sr 1-} x TiO 3, BaTi x Zr 1-x O 3, polyester / melamine resin paste, polymethyl methacrylate, Organic materials such as polyvinyl chloride, polyvinyl alcohol, polyvinyl phenol, polystyrene, and cyanoethyl pullulan can be used.

  The insulating layer 105 can also be formed by heat-pressing an insulating film-like hot melt adhesive. A hot melt adhesive is an adhesive that has a property of being solid and non-tacky at room temperature, becoming liquid upon heating and exhibiting fluidity, and returning to the original solid when cooled. The hot melt adhesive does not require the drying process required by the above-described application method, and has the advantage that the problem of ink wetting that often becomes a problem in the application method does not occur.

  Examples of the hot melt adhesive include rubber hot melt, olefin hot melt, EVA hot melt, acrylic hot melt, polyamide hot melt, polyurethane hot melt, and the like. If it is, it will be used without being specifically limited.

  The hot melt adhesive has a bulk form or a film form, but in the present invention, a film form is used. The film-like hot melt adhesive is a film-like support formed by applying a hot melt adhesive to a thickness of several μm to several hundred μm.

  Thermal lamination is preferably used as a method for hot-pressing a hot melt adhesive. Since the hot melt adhesive flows in the thermal lamination, the thickness of the hot melt adhesive at the top of the bump 104 becomes very thin, and the voltage required for dielectric breakdown can be effectively reduced.

  The thickness of the insulating layer 105 is not particularly limited, and is optimized in consideration of the shape and surface roughness of the bump, a desired write voltage, and the like.

  The information recording element and the information recording apparatus of the present invention can be manufactured by sequentially forming the above constituent elements.

  First, the lower wiring 103 is formed on the substrate 102, and then the conductive bump 104 is formed on the lower wiring 103. The conductive bump 104 may be formed on the lower electrode formed on the lower wiring 103. Since the lower electrode can be patterned simultaneously with the lower wiring 103, the lower wiring 103 including the lower electrode is used here.

  Next, the insulating layer 105 is formed on the substrate 102 so as to cover the conductive bumps 104. As described above, if the coating method or the hot-melt adhesive thermocompression bonding method is used, the thickness of the insulating layer 105 becomes thin at the top of the conductive bump 104, so that the voltage required for dielectric breakdown can be reduced. it can. In particular, when the film thickness of the insulating layer (on the planar substrate) is smaller than the height of the conductive bump, the write voltage can be effectively reduced.

  Next, the upper wiring 106 is formed on the insulating layer so as to be directly above the conductive bump. An upper electrode connected to the upper wiring 103 may be formed, and the upper electrode may be disposed immediately above the conductive bump. The upper electrode can be patterned simultaneously with the upper wiring 106. The upper wiring 106 including the upper electrode portion is used.

  Through the above steps, the information recording apparatus of the present invention can be manufactured. Of course, another process can be appropriately added between the processes. For example, when a wiring, a bump, and an insulating layer are formed using a coating method, drying and heat treatment can be performed for each step or after the formation. When a hot melt adhesive is used for forming the insulating layer, the heat treatment temperature of the upper wiring 106 is preferably smaller than the melting temperature of the hot melt adhesive. When heated above the melting temperature, the upper wiring material may enter the hot melt adhesive and become conductive.

  As described above, according to the method for manufacturing the information recording apparatus of the present invention, the conductive bump 106 can be formed by a printing method, and the insulating layer 105 can be formed by a coating method or a laminating method. Moreover, since it is possible to manufacture without producing a vacuum film in each manufacturing process, flexibility, weight reduction, and cost reduction are possible.

  In this embodiment, the information recording apparatus of the present invention (lower wiring number: 10, upper wiring number: 10, wiring width / pitch: 50 μm / 300 μm, bump number: 100, bump size / pitch: 100 μ / 300 μm) and manufacturing method thereof An example is shown.

  First, as the substrate 102, a polyethylene naphthalate (PEN) film (manufactured by Teijin DuPont) was prepared. Next, after nano Ag ink was printed on the substrate 102 by the reverse offset printing method, heat treatment was performed at 180 ° C. for 1 hour to form the lower wiring 103.

  Next, a silver paste (AGEP301X, manufactured by Sumitomo Electric Industries, Ltd.) is screen-printed on the lower wiring 103, followed by heat treatment at 180 ° C. for 30 minutes, and bumps 104 (height 15 μm, 10-point average surface roughness (Rz)) = 1.0 μm).

  Next, a film-like EVA hot melt adhesive (5 μm thickness) is thermally laminated so as to cover the substrate 102, the lower wiring 103 and the conductive bump 104 (temperature: 150 ° C., linear pressure: 6 kg / cm, speed). : 20 mm / s), an insulating layer 105 was formed.

Next, silver paste (product name “CA-42” manufactured by Ajinomoto Fine Techno Co., Ltd.) was screen-printed and heat-treated at 90 ° C. for 30 minutes to form the upper wiring 106, thereby obtaining the information recording apparatus 100.

In the obtained information recording apparatus 100, when a voltage of 0.1 V was applied to the end portion of the upper electrode and the end portion of the lower electrode that were arbitrarily selected, no conduction was observed. Subsequently, when a voltage of 3 V was applied, everything was conducted and writing by dielectric breakdown was possible.

  As an application of the information recording apparatus of the present invention, for example, a memory for recording individual identification information on an electronic tag can be considered.

DESCRIPTION OF SYMBOLS 100 ... Information recording apparatus 102 ... Board | substrate 103 ... Lower wiring (lower electrode)
104 ... Bump 105 ... Insulating layer 106 ... Upper wiring (upper electrode)

Claims (10)

  A substrate, a lower electrode provided on the substrate, a conductive bump provided on the lower electrode, an insulating layer provided to cover the conductive bump on the substrate, and a conductive bump on the insulating layer And an upper electrode provided immediately above the information recording element.   The information recording element according to claim 1, wherein the bump includes conductive fine particles.   The information recording element according to claim 2, wherein the conductive fine particles have an average particle diameter of 1 μm to 5 μm.   4. The information recording element according to claim 1, wherein the conductive bump has a 10-point average surface roughness Rz in a range of 0.5 to 5 [mu] m.   An information recording apparatus comprising the information recording element according to claim 1.   5. The information recording element according to claim 1, comprising a plurality of upper wirings and a plurality of lower wirings intersecting with the upper wirings, wherein the information recording element according to claim 1 is connected to a location where the upper wiring and the lower wiring intersect. An information recording apparatus characterized by that. Forming a lower wiring on the substrate;
Forming conductive bumps on the lower wiring;
Forming an insulating layer on the substrate so as to cover the conductive bump;
Forming the upper wiring on the insulating layer so as to be directly above the conductive bump;
Manufacturing method of information recording apparatus having   8. The method of manufacturing an information recording apparatus according to claim 7, wherein the insulating layer is formed by a coating method.   8. The method of manufacturing an information recording apparatus according to claim 7, wherein the insulating layer is formed by heat-pressing a film-like hot melt adhesive.   10. The method of manufacturing an information recording apparatus according to claim 7, wherein the conductive bump is formed by screen printing a paste containing conductive fine particles.

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