JP2007300038A - Electronic component package, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic component package and its manufacturing method which reduces the connection resistance to electronic components, and prevents lands of a wiring pattern from being stripped from an insulating resin board. <P>SOLUTION: On one surface of an insulating resin board 1, the package has adhesion-reinforced parts 4 provided at least at lands 2a, 2b for mounting electronic components, a wiring pattern 2 having conductive resin lands 2a, 2b provided on the adhesion-reinforced parts 4, and electronic components 3 mounted through connecting electrodes 5a, 5b formed on the lands 2a, 2b. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electronic component mounting body in which a chip component is solder-mounted on a wiring pattern of a substrate, and a manufacturing method thereof.

  In recent years, with the miniaturization of electronic devices, it has been desired to mount electronic components on a substrate in a small and thin manner. Therefore, in order to place the board in a limited space, development of a flexible wiring board (FPC) in which a conductor pattern (hereinafter referred to as “wiring pattern”) is formed on a thin and flexible resin board has progressed. It is out. And since a flexible wiring board can be bent and arrange | positioned using the softness | flexibility, for example, the space of an electronic device can be used effectively and the freedom degree of the design of an electronic device can be improved. In addition, by using a flexible wiring substrate made of a thin resin substrate, it is possible to flexibly cope with downsizing of electronic devices.

  Therefore, in order to mount and mount an electronic component such as a chip component on the wiring pattern of the flexible wiring board, it is required to develop a flexible wiring board that is inexpensive and has a simple manufacturing method and high reliability.

  In order to give flexibility to the flexible wiring board, a film having a high melting point and a low melting point such as polyethylene terephthalate (PET) is used as the resin substrate. Therefore, the wiring pattern cannot be formed at a high temperature (for example, 250 ° C.) like a rigid printed wiring board made of, for example, a glass epoxy substrate, and it is necessary to provide the wiring pattern at a low temperature so that the substrate does not deform. .

  Therefore, as a method of forming a wiring pattern at a low temperature, a conductive resin paste such as silver (Ag) (hereinafter referred to as “silver paste”) is directly screen printed on a resin substrate, and then heated and dried. There is a method of forming a wiring pattern.

  However, when an electronic component is mounted on a wiring pattern made of silver paste, there is a problem as described below with reference to FIG.

  4A is a conceptual plan view illustrating a conventional electronic component mounting body, and FIG. 4B is a conceptual cross-sectional view taken along line AA of FIG. 4A. Note that FIG. 4B shows an electronic component in a different view from the plan view of FIG. 4A in order to clarify the phenomenon.

  As shown in FIG. 4, the resin substrate 50 has land portions 62a and 62b at positions where electronic components 55 such as chip components are mounted and mounted thereon with silver paste, for example, two wiring patterns 62 facing each other, After being formed by screen printing, it is formed by drying and curing.

  A solder layer (not shown) is formed on the land portions 62a and 62b with a low melting point solder material having a melting point of about 138 ° C. such as tin (Sn) -bismuth (Bi). Then, the electrode portion of the electronic component 55 is placed on the solder layer on the land portions 62a and 62b, and the electronic component 55 and the land portions 62a and 62b are connected by melting a low melting point solder at, for example, about 150 ° C. Electrode portions 63a and 63b are formed and connected. At this time, the connection electrode portions 63a and 63b are alloyed with the silver of the land portions 62a and 62b to form tin-bismuth-silver.

  However, in general, the adhesive force between the resin substrate and the silver paste is weak, and the silver component dissolves into the solder and sucks up during the expansion / contraction or alloying when the connection electrode parts 63a and 63b are formed by alloying. Due to a phenomenon called “crab”, there arises a problem that the connection electrode parts 63 a and 63 b are peeled off from the resin substrate 50.

  An example of forming a nickel (Ni) layer as an anti-diffusion layer by an electroless plating process on a wiring pattern formed by drying and curing a wiring pattern using silver paste as a method for improving the above problem Is disclosed (for example, see Patent Document 1).

  Below, the electronic component mounting body described in Patent Document 1 will be described with reference to FIG.

  FIG. 5A is a conceptual plan view for explaining a conventional electronic component mounting body, and FIG. 5B is a conceptual cross-sectional view taken along line AA of FIG. In FIG. 5, the same components as those in FIG.

  As shown in FIG. 5, a wiring pattern 62 having lands 62 a and 62 b is formed on a resin substrate 50 with silver paste. Then, a nickel layer is formed as diffusion preventing layers 74a and 74b on the land portions 62a and 62b by plating. Furthermore, solder layers 73a and 73b made of a low melting point solder material are provided on the diffusion preventing layers 74a and 74b. Then, the electrode portion of the electronic component 55 is placed on the diffusion preventing layers 74a and 74b of the land portions 62a and 62b, and the low melting point solder that is the solder layers 73a and 73b is melted at about 150 ° C. 62b and the electronic component 55 are connected.

  That is, according to Patent Document 1, by providing the diffusion prevention layers 74a and 74b on the land portions 62a and 62b, the solder layers 73a and 73b are made of conductive material such as low melting point solder and silver of the wiring pattern 62 as the material. Interdiffusion between the particles can be prevented. Thereby, since the solder layers 73a and 73b are not alloyed, it is considered that a decrease in adhesive strength between the resin substrate 50 and the wiring pattern 62 due to, for example, expansion / contraction or silver erosion can be prevented.

  As another method for improving the above problem, a conductive pattern dispersion liquid droplet is applied and printed by an inkjet method on an adhesive tape comprising a base substrate and an adhesive layer, and then dried to form a wiring pattern. Is disclosed (for example, see Patent Document 2).

According to this, since the wiring pattern is formed on the adhesive tape, the adhesion between the base substrate and the wiring pattern is improved.
JP-A-4-3490 JP 2004-304129 A

  However, in the configuration in which a diffusion prevention layer made of a nickel layer is provided on the land portion of the wiring pattern shown in Patent Document 1, a wet process called plating treatment is required on the land portion, which complicates the manufacturing process. There is a problem that the cost increases due to the treatment of a waste solution such as a plating solution.

  Moreover, the wiring pattern formed using the ink jet disclosed in Patent Document 2 has a problem that the ink jet device is expensive and the manufacturing cost is high. In addition, since the adhesive layer is provided on the entire surface of the base substrate, there is a problem that dust and foreign matters are likely to adhere to portions other than the wiring pattern, resulting in an electrical failure such as a short circuit. In addition, there are no disclosures regarding problems with electronic component mounting bodies in which electronic components are mounted on a wiring pattern and measures for improving them.

  The present invention has been made in order to solve the above-described problems. An electronic component mounting body capable of reducing connection resistance with an electronic component and preventing separation between an insulating resin substrate and a land portion of a wiring pattern, and its manufacture It aims to provide a method.

  In order to solve the above-described object, an electronic component mounting body according to the present invention has an adhesive strength reinforcing portion provided on one surface of an insulating resin substrate and provided at least at a land portion where an electronic component is mounted. The wiring pattern having a land portion made of a conductive resin provided on the force reinforcing portion and an electronic component mounted via a connection electrode portion formed on the land portion.

  Furthermore, the adhesive force reinforcement part may consist of the contact bonding layer by an adhesive agent or an adhesive sheet.

  Furthermore, the adhesive force reinforcement part may be formed by roughening the surface of the insulating resin substrate.

  Further, the conductive resin may contain a silver filler as a main component.

  Further, the connection electrode portion may contain a low melting point solder.

  Further, the low melting point solder may contain tin-bismuth or tin-indium.

  As a result, since the connection electrode portion is formed of an alloy layer of the electronic component and the land portion, the connection resistance can be reduced. Furthermore, peeling from the insulating resin substrate due to alloying of the connection electrode portion can be prevented by forming an adhesive strength reinforcing portion under the land portion.

  Further, the method of manufacturing an electronic component mounting body according to the present invention includes a step of forming an adhesive strength reinforcing portion provided at least at a position of a land portion on which an electronic component is mounted on one surface of an insulating resin substrate, The method includes a step of forming a wiring pattern having a land portion made of a conductive resin provided on the force reinforcing portion, and a step of mounting an electronic component via a connection electrode portion formed on the land portion.

  Furthermore, the step of forming the adhesive strength reinforcing portion may include a step of forming an adhesive layer using an adhesive or an adhesive sheet.

  Furthermore, the step of forming the adhesive strength reinforcing portion may include a step of roughening the surface of the insulating resin substrate.

  Accordingly, it is possible to easily produce an electronic component mounting body with excellent reliability for reducing the connection resistance with the electronic component and preventing the separation from the insulating resin substrate at the land portion.

  According to the electronic component mounting body and the manufacturing method thereof of the present invention, the connection resistance can be reduced because the connection electrode portion is formed of the alloy layer. Furthermore, it is possible to manufacture a highly reliable electronic component mounting body that can prevent the land portion from peeling off from the insulating resin substrate due to alloying of the connection electrode portion.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1A is a conceptual plan view illustrating an electronic component mounting body according to a first embodiment of the present invention, and FIG. 1B is a conceptual cross-sectional view taken along line AA of FIG.

  As shown in FIG. 1, the electronic component mounting body 10 includes at least a land portion 2a on which an electronic component 3 is mounted on one surface of a flexible insulating resin substrate 1 made of, for example, a polyethylene terephthalate (PET) resin film. Under the 2b, it has the adhesive force reinforcement part 4 which consists of adhesive agents, such as an epoxy resin, which exists. On the adhesive strength reinforcing portion 4, at least a wiring pattern 2 including land portions 2a and 2b formed of a conductive resin mainly containing a silver filler or the like in a binder is provided to face each other. . Further, in the land portions 2a and 2b, a solder layer (not shown) made of a low melting point solder material such as tin-bismuth is provided, and after mounting the electronic component 3, the solder layer is melted to form the electronic component 3 Are mounted via the connection electrode portions 5a and 5b to form the electronic component mounting body 10. At this time, the connection electrode portions 5a and 5b are configured in a state where silver in the conductive resin and tin-bismuth in the solder layer are alloyed.

  Here, as the insulating resin substrate 1, in addition to a polyester resin film such as polyethylene terephthalate (PET) or polybutylene terephthalate, for example, polyolefin such as polyethylene or polypropylene, polyimide resin, polysulfide film, polyaromatic amide film. Etc. can be used.

  As the adhesive force reinforcing portion 4, for example, an adhesive or an adhesive sheet can be used as the adhesive layer. And as adhesive material of an adhesive agent or an adhesive sheet, adhesive materials, such as a polyester type, a polyamide type, a polyacrylic resin, can be used other than an epoxy resin, for example. As a result, the adhesive strength between the insulating resin substrate 1 and the land portions 2a and 2b can be improved.

  Moreover, as a filler of the conductive resin of the wiring pattern 2 provided with the land portions 2a and 2b, in addition to the silver filler, silver as a main component, for example, metal particles such as copper, gold, nickel, palladium, tin, and the like Alloy particles or the like can be used. And the shape is not particularly limited, but a scale-like one is preferable because the conductivity can be further improved. Furthermore, the size of the filler is, for example, in the case of a spherical shape, an average particle size of about 0.1 μm to several tens of μm is used. .

  The binder of the conductive resin contains a thermosetting resin as a main component. And as a thermosetting resin, an epoxy resin, a phenol resin, a polyimide resin, a polyurethane resin, a melamine resin, a urea resin etc. are used, for example. Furthermore, it can also be used by 1 type, or 2 or more types of these mixed systems.

  As a low melting point solder for the solder layer, in addition to tin-bismuth, tin (Sn) -indium (In), tin-bismuth-silver, tin-bismuth-indium and alloys thereof include zinc (Zn) and copper (Cu). You may use what added these. Thereby, since the range of selections, such as required connection resistance and reaction temperature, can be expanded, the adaptive range of an electronic component mounting body can be expanded.

  Examples of electronic components include chip components such as chip resistors, chip capacitors, and chip inductors, and semiconductor elements such as IC chips.

  With the above configuration, the electronic component 3 and the wiring pattern 2 can be connected with a low connection resistance by the connection electrode portions 5a and 5b in which the alloy layer is formed of the conductive resin silver and the solder layer of the land portions 2a and 2b. it can. Further, the adhesive strength reinforcing portion 4 prevents the connection electrode portions 5a and 5b from peeling off the land portions 2a and 2b connected to the electronic component 3 from the insulating resin substrate 1 due to expansion and contraction or silver erosion during alloying. can do.

  According to the first embodiment of the present invention, the connection resistance between the electronic component and the wiring pattern is low, and the adhesion strength between the insulating resin substrate and the wiring pattern is high and the reliability is high without causing peeling. An electronic component mounting body can be realized.

  Further, since the connection electrode portion is formed of an alloy layer such as tin-bismuth-silver, the connection reliability can be further improved by improving the oxidation resistance and brittleness.

  Hereinafter, the manufacturing method of the electronic component mounting body in the 1st Embodiment of this invention is demonstrated using FIG.

  FIG. 2 is a conceptual cross-sectional view illustrating the steps of the method for manufacturing the electronic component mounting body in the first embodiment of the present invention. In addition, the same code | symbol is attached | subjected and demonstrated to the same component as FIG.

  First, as shown in FIG. 2 (a), for example, an epoxy resin adhesive is used so as to be present at least at the position of the land portion on which the electronic component is mounted on one surface of the insulating resin substrate 1. The adhesion reinforcing part 4 is formed by, for example, a screen printing method.

  Next, as shown in FIG. 2 (b), a conductive resin mainly comprising a silver filler is used for the wiring pattern 2 that covers at least a part of the adhesive strength reinforcing portion 4 and includes the land portions 2a and 2b. For example, after forming by screen printing, it is formed by heating and drying.

  Next, as shown in FIG. 2 (c), solder layers 3a and 3b are formed on the land portions 2a and 2b by a low melting point solder material containing tin-bismuth (Sn-58Bi) or the like. And at least a corresponding position by, for example, screen printing.

  Next, as shown in FIG. 2 (d), it is passed through a furnace (not shown) having a temperature (about 150 ° C.) slightly higher than the melting point of the low melting point solder (about 138 ° C.) over a predetermined time. At that time, by heating in the furnace, the solder layers 3a and 3b made of tin-bismuth as the material melt in the connection electrode portions 5a and 5b, and alloyed with silver in the conductive resin of the land portions 2a and 2b. To do. Then, an alloy containing tin-bismuth-silver is formed as the connection electrode portions 5a and 5b, and the electronic component 3 is electrically connected to the land portions 2a and 2b. As a result, the electronic component 3 is mounted on the land portions 2a and 2b of the wiring pattern 2 via the connection electrode portions 5a and 5b.

  In the present embodiment, the silver paste for forming the wiring pattern 2 is a mixture of spherical powder and scaly powder having a particle diameter of, for example, 2 μm to 20 μm mainly composed of silver filler dispersed in an insulating resin. Using. And as insulating resin, what added amine imidazole as a hardening | curing agent to the liquid mixture of the bisphenol A type epoxy and the bisphenol F type epoxy, for example was used. Furthermore, the compounding ratio of the insulating resin and the mixed filler was such that the solid content ratio of the silver filler was, for example, 80 wt% to 90 wt%, and these materials were uniformly dispersed in a kneader to prepare a silver paste.

  Depending on the construction method using the silver paste, a diluent such as butyl carbitol may be added to adjust the viscosity of the silver paste. However, if the boiling point of the diluent is too low, the viscosity of the silver paste increases due to the volatilization of the diluent, and printing defects may occur. On the other hand, if the boiling point is too high, the diluent does not completely evaporate when the silver paste is cured and remains in the silver paste, which may result in poor curing and reliability. Therefore, it is important to select a suitable diluent and produce a silver paste.

  The silver paste thus prepared can be cured, for example, by heating in a hot air drying furnace, and a conductive wiring pattern can be formed by contacting and fixing the silver fillers. The time required for curing varies depending on the curing temperature, but in the case of a general silver paste, it is about several tens of minutes to about 1 hour at 180 degrees.

  As a result, a wiring pattern having a volume resistivity of about 20 μΩcm to several hundreds μΩcm is obtained.

  Note that a silver filler is generally used for the conductive resin, but copper, gold, aluminum, nickel, silver palladium, or the like may be used as the conductive filler instead of the silver filler.

  Moreover, when it is desired to give flexibility to the insulating resin in which the conductive filler is dispersed, a polyester resin may be used. Further, when it is desired to increase the force for bringing the conductive filler into contact, a phenol resin having a strong curing shrinkage force of the insulating resin may be used.

  According to the present embodiment, the connection resistance between the wiring pattern and the electronic component can be reduced by the alloyed connection electrode portion. In addition, the adhesion reinforcing portion can prevent the land portion from being peeled off from the insulating resin substrate due to expansion / contraction during alloying or silver erosion. Furthermore, since a wet process such as plating is not used, an electronic component mounting body that is inexpensive and excellent in reliability can be easily manufactured.

  In the present embodiment, an example in which an adhesive layer is provided with an adhesive as the adhesive strength reinforcing portion 4 has been described. However, the present invention is not limited to this. For example, the surface of the insulating resin substrate 1 may be roughened by plasma treatment, etching, sandblasting, or the like, and a wiring pattern having land portions may be provided thereon. In addition, an adhesive may be applied, printed, or an adhesive sheet may be pasted on the roughened surface, and a wiring pattern having a land portion may be provided thereon. As a result, the adhesive strength between the insulating resin substrate and the land portion can be improved with a simple structure, and the adhesive strength can be further increased.

  Moreover, it is preferable to form the adhesive force reinforcement part 4 larger than the area which land part 2a, 2b occupies. Thereby, the intensity | strength which the land parts 2a and 2b peel from the insulating resin substrate 1 can be improved.

  In the present embodiment, the example in which the adhesive strength reinforcing portion 4 is provided at the positions of the land portions 2a and 2b of the wiring pattern 2 has been described. However, the present invention is not limited thereto. For example, it may be provided so as to cover each land portion of a plurality of adjacent wiring patterns, or may be formed under the wiring pattern. Thereby, since an adhesion area becomes large, the adhesive force between an insulating resin substrate and each land part can further be improved.

(Second Embodiment)
FIG. 3A is a schematic plan view for explaining an electronic component mounting body according to the second embodiment of the present invention, and FIG. 3B is a conceptual cross-sectional view taken along the line AA of FIG. In addition, the same code | symbol is attached | subjected and demonstrated to the same component as FIG.

  FIG. 3 is different from FIG. 1 in that an adhesion reinforcing portion is individually arranged and provided on one surface of the insulating resin substrate corresponding to at least the position of each land portion on which the electronic component is mounted. Is different.

  That is, as shown in FIG. 3, the electronic component mounting body 20 is formed on one surface of the insulating resin substrate 1 in correspondence with at least the positions of the land portions 22a and 22b on which the electronic component 3 is mounted, for example, epoxy. Adhesive strength reinforcing portions 24a and 24b made of an adhesive such as resin are provided separately.

  On the adhesive strength reinforcing portions 24a and 24b, at least a wiring pattern 22 including land portions 22a and 22b formed of a conductive resin mainly containing a silver filler or the like in a binder is provided to face each other. ing. Further, in the land portions 22a and 22b, a solder layer (not shown) made of a low melting point solder material such as tin-bismuth is provided, and after mounting the electronic component 3, the solder layer is melted, for example, a chip The electronic component mounting body 20 is configured by mounting the electronic component 3 such as a component via the connection electrode portions 25a and 25b. At this time, the connection electrode portions 25a and 25b are configured in a state where silver in the conductive resin and tin-bismuth in the solder layer are alloyed.

  In addition, the wiring pattern provided with the insulating resin substrate, the adhesive strength reinforcing portion, and the land portion is the same as the material and the manufacturing method described in the first embodiment, and description thereof is omitted. Also, the same electronic components as those in the first embodiment can be used.

  In addition, the electronic component mounting body manufacturing method according to the second embodiment of the present invention can be basically manufactured by the same method except that the adhesive strength reinforcing portions are individually formed corresponding to the land portions. Is omitted.

  According to the second embodiment of the present invention, the electronic parts and the wiring pattern are reduced by the connection electrode portions 25a and 25b in which the alloy layers are formed of the conductive resin silver and the solder layer of the land portions 22a and 22b. It can be connected with connection resistance. Furthermore, it is possible to prevent the electronic component 3 from being peeled off from the insulating resin substrate 1 due to expansion / contraction or silver erosion when the connection electrode portions 25a and 25b are alloyed, by the adhesive strength reinforcement portions 24a and 24b.

  In addition, the configuration in which the adhesive strength reinforcing portions are individually provided corresponding to the positions of the land portions can prevent adhesion of foreign matters to the adhesive strength reinforcing portions in the gap between the electronic components and the insulating resin substrate, for example. it can.

  In addition, it is not necessary to limit the adhesive strength reinforcement part to an adhesive made of an insulating material by the configuration in which the adhesive strength reinforcement part is individually provided corresponding to the position of the land part, and it is optimal for various applications. An adhesive or an adhesive sheet can be used. For example, formed using conductive fine particles such as silver filler and a conductive adhesive obtained by mixing and kneading, for example, 80:20 (Wt%) of a resin adhesive such as an amine-curing epoxy resin adhesive. You can also

  As a result, the adhesive strength reinforcing portion provided corresponding to each land portion can be formed with a conductive adhesive, so that the adhesive force between the land portion and the insulating resin substrate can be improved and the effect of lowering the connection resistance is also expected. it can.

  In each of the above embodiments, the example in which the wiring pattern including the land portion is formed has been described. However, the present invention is not limited to this. For example, a protective film made of an insulating resin such as a resist may be provided in a region other than the land portion of the formed wiring pattern. Thereby, migration of the wiring pattern such as silver can be prevented, and an electronic component mounting body excellent in moisture resistance and environmental resistance can be obtained.

  The electronic component mounting body and the manufacturing method thereof according to the present invention require a flexible wiring board having low cost, high reliability, and flexibility to mount the electronic component. Useful.

(A) Plan view conceptual diagram explaining the electronic component mounting body in the first embodiment of the present invention (b) AA cross-sectional conceptual diagram of FIG. Sectional conceptual diagram explaining the process of the manufacturing method of the electronic component mounting body in the 1st Embodiment of this invention (A) Plan conceptual diagram explaining the electronic component mounting body in the 2nd Embodiment of this invention (b) AA sectional view conceptual drawing of the same figure (a). (A) Plane conceptual diagram for explaining a conventional electronic component mounting body (b) AA line sectional conceptual diagram of FIG. (A) Plane conceptual diagram for explaining a conventional electronic component mounting body (b) AA line sectional conceptual diagram of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insulating resin substrate 2,22 Wiring pattern 2a, 2b, 22a, 22b Land part 3 Electronic component 3a, 3b Solder layer 4, 24a, 24b Adhesive force reinforcement part 5a, 5b, 25a, 25b Connection electrode part 10,20 Electron Component mounting body

Claims (9)

On one side of the insulating resin substrate,
An adhesive strength reinforcing portion provided at least at the position of the land portion on which the electronic component is mounted;
A wiring pattern having the land portion made of a conductive resin provided on the adhesive strength reinforcing portion;
The electronic component mounted via the connection electrode portion formed in the land portion;
An electronic component mounting body comprising: The electronic component mounting body according to claim 1, wherein the adhesive strength reinforcing portion includes an adhesive layer made of an adhesive or an adhesive sheet. The electronic component mounting body according to claim 1, wherein the adhesion reinforcing portion is formed by roughening a surface of the insulating resin substrate. The electronic component mounting body according to any one of claims 1 to 3, wherein the conductive resin contains a silver filler as a main component. The electronic component mounting body according to any one of claims 1 to 4, wherein the connection electrode portion includes a low melting point solder. The electronic component mounting body according to claim 5, wherein the low melting point solder contains tin-bismuth or tin-indium. On one side of the insulating resin substrate,
Forming an adhesive strength reinforcing portion provided at least at a position of a land portion on which an electronic component is mounted;
Forming a wiring pattern having the land portion made of a conductive resin provided on the adhesive strength reinforcing portion;
Mounting the electronic component via a connection electrode portion formed in the land portion;
The manufacturing method of the electronic component mounting body characterized by including this. The method of manufacturing an electronic component mounting body according to claim 7, wherein the step of forming the adhesive strength reinforcing portion includes a step of forming an adhesive layer made of an adhesive or an adhesive sheet. The method of manufacturing an electronic component mounting body according to claim 7 or 8, wherein the step of forming the adhesive strength reinforcing portion includes a step of roughening a surface of the insulating resin substrate.

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