JP5655770B2 - Electronic component and method of manufacturing the electronic component - Google Patents

Description

  The present invention relates to an electronic component and a method for manufacturing the electronic component. More specifically, the present invention relates to an electronic component including a terminal having at least one of a lead-free plating layer and a lead-free solder on the surface of a base material, and suppresses whisker growth from the lead-free plating layer and the lead-free solder. The present invention relates to a manufactured electronic component and a method for manufacturing the electronic component.

  In recent years, for example, electronic components such as a semiconductor device in which an IC chip is mounted on a lead frame have been required to be further miniaturized, and the interval between terminals of the electronic component has been reduced to about several hundred μm. As a base material for terminals of such electronic parts, brass, copper alloy, iron nickel alloy (“Fe—Ni”) called “42 alloy” or the like is often used, but the base material base is still exposed. Since the surface of the terminal is oxidized in the state, there is a risk of causing a conduction failure due to, for example, a soldering failure. Therefore, a plating layer is generally formed as a protective film on the surface of the terminal to prevent oxidation of the surface of the terminal. Has been done. As a material for the plating layer, tin (Sn) or a tin alloy is mainly used.

  In addition, although the alloy containing lead (Pb) has been conventionally used as a material for the plating layer, in recent years, lead-free has been demanded from the viewpoint of reducing the environmental load. As the material of the terminal plating layer, for example, a material that does not contain lead, such as tin (Sn), tin copper alloy (Sn—Cu), tin silver alloy (Sn—Ag), tin bismuth alloy (Sn—Bi), or the like. It is sought to use. However, it is known that when the surface of the terminal of an electronic component is plated using a lead-free material, whiskers are generated, and when the distance between the terminals is as narrow as several hundred μm as described above, There is a possibility that a short circuit occurs between the terminals of the electronic component due to the occurrence.

  As a measure for avoiding the above problem, in this technical field, for example, a lead-free plating layer is formed on the surface of the terminal of an electronic component by electrolytic plating with tin or a tin-based alloy, and a coating layer such as an epoxy resin is formed. By forming on the surface, whiskers generated from the plating layer are suppressed inside the coating layer, and the whisker is prevented from growing outward to such a size as to cause a short circuit between the terminals of the electronic component. Has been proposed (see, for example, Patent Document 1). However, it is difficult to completely suppress whisker growth by simply covering the lead-free plating layer formed on the surface of the terminal of the electronic component with a resin film layer as described above. The possibility of reaching the outside and causing a short circuit between the terminals of the electronic component cannot be wiped out.

  Therefore, in this technical field, a lead-free plating layer formed on the surface of the terminal of the electronic component is formed, and the surface of the plating layer is hard with higher mechanical strength than the whisker generated from the lead-free plating layer. It has been proposed to form a thin film (DLC (diamond-like carbon) thin film, silicon nitride thin film, or carbon nitride thin film) (see, for example, Patent Document 2). However, since the hard thin film is formed by a technique such as sputtering before soldering the terminals of the electronic component, there is a possibility that the wettability of the solder may be hindered. In addition, in the technique according to the proposal, since it is necessary to perform a sputtering process on a minute terminal (the end portion of the lead frame), it is difficult to guarantee accuracy, which may lead to an increase in manufacturing cost and manufacturing period.

  Moreover, in the said technical field, the lead-free plating layer formed in the surface of the terminal of an electronic component is formed, and the surface of the said plating layer is a moisture-proof resin coating layer which has a spring hardness of 80-85 degrees. It is proposed to coat (see, for example, Patent Document 3). However, in the technology according to the proposal, there are problems in manufacturing such as a decrease in manufacturing efficiency due to the time required for curing the resin coating layer and a variation in thickness of the resin coating layer due to dripping during curing. In addition, since the resin coating layer is hard, there is a possibility that the resin coating layer may be peeled off from the terminal due to a difference in thermal expansion coefficient between the resin coating layer and the metal terminal (lead frame).

  Furthermore, in this technical field, a lead-free plating layer formed on the surface of a terminal of an electronic component is formed, and a layered structure or sea island made of a plurality of types of resin materials having different thermal expansion coefficients is formed on the surface of the plating layer. It has been proposed to form a coating layer having a structure. According to the technology related to the proposal, when a temperature change occurs in the electronic component, the plurality of types of resin materials forming the coating layer expand and contract in different sizes based on different thermal expansion coefficients. By repeating, a shear stress acts on the whisker grown inside the coating layer, the whisker is divided by the shear stress and loses conductivity, and as a result, the whisker is caused between the terminals of the electronic component. It has been proposed to avoid short circuits.

  However, in the technique according to the above proposal, since the plurality of types of resin materials forming the coating layer are not firmly bonded to each other, the strength and the robustness of the coating layer may be insufficient. In addition, when an inorganic filler or the like is mixed into the resin material constituting the coating to change the thermal expansion coefficient of the resin material, if the whisker grown inside the coating layer contacts the filler, the filler should be avoided. As a result, the whisker may grow to the outside of the coating. Furthermore, when a coating layer having a layered structure is employed, there is a possibility that the coating layer application process is multiplexed and the manufacturing process of the electronic component is complicated.

  As described above, in this technical field, a lead-free plating layer formed on the surface of a terminal of an electronic component, although suppression of whiskers is attempted by using a resin-based coating material, an inorganic hard thin film, a filler-containing coating, or the like In addition, a method capable of effectively and practically suppressing whisker growth from lead-free solder has not yet been established. Therefore, in this technical field, there is a need for a technique that can effectively and practically suppress the growth of whiskers from the lead-free plating layer and lead-free solder formed on the surface of the terminal of the electronic component.

JP 2005-302575 A JP 2008-147589 A JP 2009-038075 A

  As described above, in the technical field, lead-free plating layers formed on the surface of the terminals of electronic components, although attempts have been made to suppress whiskers by using resin-based coating materials, inorganic hard thin films, filler-containing coatings, etc. In addition, a method capable of effectively and practically suppressing whisker growth from lead-free solder has not yet been established. Therefore, in this technical field, there is a need for a technique that can effectively and practically suppress the growth of whiskers from the lead-free plating layer and lead-free solder formed on the surface of the terminal of the electronic component.

  The present invention has been made to meet such a demand. More specifically, an object of the present invention is to effectively and practically suppress the growth of whiskers from a lead-free plating layer and lead-free solder formed on the surface of a terminal of an electronic component.

One object of the present invention is to
An electronic component comprising a terminal having at least one of a lead-free plating layer and a lead-free solder on the surface of a base material,
At least an exposed surface of the lead-free plating layer and the lead-free solder is covered with a coating layer;
The coating layer comprises a first material and a second material dispersed in the first material;
The second material is a material that starts curing by contact with a third substance different from any of the first material and the second material.
Achieved by electronic components.

Also, the above one object of the present invention is to
A method for manufacturing an electronic component comprising a terminal having at least one of a lead-free plating layer and a lead-free solder on the surface of a base material,
Covering at least an exposed surface of the lead-free plating layer and the lead-free solder with a coating layer;
Including
The coating layer comprises a first material and a second material dispersed in the first material;
The second material is a material that starts curing by contact with a third substance different from any of the first material and the second material.
This is also achieved by a method for manufacturing an electronic component.

  ADVANTAGE OF THE INVENTION According to this invention, the growth of the whisker from the lead-free plating layer and lead-free solder formed in the surface of the terminal of an electronic component can be suppressed effectively and practically. More specifically, according to the present invention, in an electronic component comprising a terminal having at least one of a lead-free plating layer and a lead-free solder on the surface of a base material, at least the lead-free plating layer and the lead-free solder The exposed surface is a coating layer comprising a first material and a second material dispersed in the first material, wherein the second material is different from the first material and the third material. By covering with a coating layer, which is a material that begins to harden upon contact, the growth of whiskers generated from the lead-free plating layer and the lead-free solder is suppressed by the second material, so that the whisker can reach the outside of the coating layer. You can avoid growing.

It is a schematic diagram explaining the generation | occurrence | production state of the whisker in the surface of the terminal with which the electronic component which concerns on one embodiment of this invention is provided. It is a schematic diagram explaining the generation | occurrence | production state of the whisker in the surface of the terminal with which the electronic component which concerns on another embodiment of this invention is provided. It is a schematic diagram explaining the coating method of the coating layer in the manufacturing method of the electronic component which concerns on one embodiment of this invention. It is a schematic diagram which shows the coating layer apply | coated to the electronic component by the manufacturing method of the electronic component which concerns on one embodiment of this invention. It is a schematic diagram explaining the coating method of the coating layer in the manufacturing method of the electronic component which concerns on another embodiment of this invention. It is a graph showing the relationship of the detection number of the whisker with respect to the compounding rate of the 2nd material in the coating layer which concerns on one embodiment of this invention. It is a graph showing the relationship of the detection number of the whisker with respect to the compounding rate of the 2nd material in the coating layer which concerns on another embodiment of this invention.

  As described above, an object of the present invention is to effectively and practically suppress the growth of whiskers from a lead-free plating layer and lead-free solder formed on the surface of a terminal of an electronic component. As a result of diligent research to achieve the above object, the present inventor gradually cures the lead-free plating layer and the lead-free solder formed on the surface of the terminal of the electronic component by contact with the third substance. The whisker generated from the lead-free plating layer and lead-free solder grows through the coating layer to the outside of the coating layer by covering with the coating layer made of the first material in which the second material is dispersed. As a result, the present invention has been conceived.

That is, the first embodiment of the present invention is:
An electronic component comprising a terminal having at least one of a lead-free plating layer and a lead-free solder on the surface of a base material,
At least an exposed surface of the lead-free plating layer and the lead-free solder is covered with a coating layer;
The coating layer comprises a first material and a second material dispersed in the first material;
The second material is a material that starts curing by contact with a third substance different from any of the first material and the second material.
It is an electronic component.

  As described above, the electronic component according to this embodiment is an electronic component including a terminal having at least one of a lead-free plating layer and a lead-free solder on a surface of a base material, and the lead-free plating layer and the lead At least an exposed surface of the free solder is an electronic component covered with a coating layer including a first material and hollow particles made of a second material dispersed in the first material.

  The electronic component according to the present embodiment is not limited to a specific type of electronic component, as long as the electronic component includes a terminal having at least one of a lead-free plating layer and a lead-free solder on the surface of the base material. Any kind of electronic component may be used. Examples of such electronic components include, for example, electronic components including semiconductor elements, resistor chips, capacitors, and the like that constitute various electronic control units (ECUs). Examples of terminals provided in these electronic components include a lead frame terminal portion as a component that supports and fixes a semiconductor element and connects to an external wiring.

  In addition, the electronic component according to this embodiment is an electronic component including a terminal having at least one of a lead-free plating layer and a lead-free solder on the surface of the base material. The free plating layer is, for example, as described above, in order to prevent poor conduction due to poor soldering due to oxidation of the surface of the terminal included in the electronic component according to the present embodiment. It is arrange | positioned on the surface of this. In addition, for example, lead-free solder is a terminal provided in these components in order to achieve electrical connection between circuit elements constituting the electronic component according to the present embodiment or between the circuit elements and the circuit board. Arranged above.

  Examples of the material constituting the lead-free plating layer and the lead-free solder include a lead (Pb) -free (lead-free) tin (Sn) -based alloy or zinc (Zn-based) alloy. In this specification, “lead-free (lead-free)” material ideally refers to a material that does not contain lead at all, but exceeds a specific content rate determined from the viewpoint of environmental protection, for example. I would like to remind you that it does not exclude materials that contain trace amounts of lead to the extent that they do not.

  The material constituting the lead-free plating layer may be pure tin or pure zinc, and the material constituting the lead-free solder may be pure tin. Preferably, the material constituting the lead-free plating layer and the lead-free solder is a tin-based alloy, specifically, a tin-copper alloy (Sn—Cu), a tin-silver alloy (Sn—Ag), a tin bismuth alloy (Sn). -Bi), a tin zinc alloy (Sn-Zn), a tin indium alloy (Sn-In), etc. can be mentioned. Furthermore, as a base material of a terminal included in the electronic component according to the present embodiment, a metal material that has been used in a conventional electronic component can be used, for example, called brass, copper alloy, or “42 alloy”. An iron-nickel alloy (Fe-Ni) can be used. These materials can be appropriately selected according to the type of electronic component and design specifications.

  As described above, the electronic component according to this embodiment is an electronic component including a terminal having at least one of a lead-free plating layer and a lead-free solder on a surface of a base material, and the lead-free plating layer and the lead At least an exposed surface of the free solder is an electronic component covered with a coating layer including a first material and hollow particles made of a second material dispersed in the first material. That is, in the electronic component according to this embodiment, the entire electronic component may be covered with the coating layer, or the lead-free plating layer and the lead-free layer as described above on the surface of the base material of the terminal included in the electronic component. Only the region where at least one of the solder is disposed may be covered with the coating layer.

  The thickness of the coating layer covering at least one of the lead-free plating layer and the lead-free solder on the surface of the base material of the terminal included in the electronic component according to this embodiment is not particularly limited, and the whisker As long as it is possible to effectively suppress the growth, it can be determined as appropriate according to, for example, the design specifications of the electronic component and the manufacturing process of the electronic component, the manufacturing cost, and the like. Specifically, the thickness of the coating layer may be equal to the thickness of the moisture-proof resin coating layer in the electronic component according to the related art, and may be, for example, in the range of 10 μm to 300 μm.

  As described above, the coating layer according to the present embodiment includes the first material and the second material dispersed in the first material, and the second material includes both the first material and the second material. It is a material that initiates curing upon contact with a different third substance. Thus, in the coating layer according to the present embodiment, at least one of the lead-free plating layer and the lead-free solder is applied to the surface of the base material of the terminal included in the electronic component according to the present embodiment. In this case, the first material is first cured, and then the second material is gradually cured by contact with the third substance. That is, in the coating layer according to this embodiment, the ratio of the cured second material gradually increases in the coating layer as time passes.

  On the other hand, whiskers are not generated at the time when the electronic component according to this embodiment is manufactured, and with the passage of time thereafter, at least the lead-free plating layer on the surface of the base material of the terminal included in the electronic component and It is generated from at least one of the lead-free solders and grows gradually. That is, the curing of the second material in the coating layer according to this embodiment and the generation and growth of whiskers proceed in parallel. Thereby, according to the coating layer which concerns on this embodiment, a 2nd material is hardened | cured gradually with the generation | occurrence | production and growth of a whisker, and a whisker contacts a hardened 2nd material, and thereby the growth of a whisker is made more efficient. Can be suppressed.

  In order to suppress whisker growth by curing the second material in the coating layer according to this embodiment as described above, the hardness of the second material after curing at least changes the whisker growth direction. It must be large enough. On the other hand, if the first material, which is another component constituting the coating layer according to the present embodiment, has a large hardness like the second material after curing, the hardness of the entire coating layer becomes excessive, for example, Due to the temperature change accompanying the operation of the electronic component, the coating layer may be peeled off from the terminal due to the difference in thermal expansion coefficient between the coating layer and the terminal of the electronic component (for example, metal lead frame). May break.

  Therefore, in the electronic component according to the present embodiment, it is desirable that the hardness after curing of the first material constituting the coating layer is smaller than the hardness after curing of the second material. In other words, in the electronic component according to this embodiment, it is desirable that the hardness after curing of the second material constituting the coating layer is larger than the hardness after curing of the first material.

Accordingly, the second embodiment of the present invention provides:
An electronic component according to the first embodiment of the present invention,
The hardness of the second material after curing is greater than the hardness of the first material after curing;
It is an electronic component.

  As described above, in the electronic component according to this embodiment, the hardness of the second material after curing is greater than the hardness of the first material after curing. Therefore, for example, even when a temperature change occurs due to the operation of the electronic component, the coating layer is not formed due to the difference in thermal expansion coefficient between the coating layer and the terminal of the electronic component (for example, a metal lead frame). The problem of peeling from the terminal or cracking of the coating layer can be suppressed. Thereby, in the electronic component according to the present embodiment, whisker growth is effectively suppressed without sacrificing the sealing function (moisture proofing function) by the coating layer, and the terminals of the electronic component as described above It is possible to effectively suppress problems such as a short circuit.

  In addition, the hardness after hardening of 1st material and 2nd material can be measured with various measuring methods. As a specific example of the method of measuring the hardness of the first material and the second material after curing, for example, a method of measuring using a spring hardness (Hs) A type durometer according to JIS K6253 (ISO48) Is mentioned.

  By the way, as described above, at least one of the lead-free plating layer and the lead-free solder on the surface of the base material of the terminal included in the electronic component according to the present invention is formed of the first material and the second material. It is covered with a coating layer made of the first material in which the second material, which is gradually cured by contact with a third substance different from any other, is dispersed. Examples of the second material that is gradually cured by contact with the third substance include a resin that is cured by a polymerization reaction or a crosslinking reaction that is initiated by contact with moisture or metal (including metal ions). Materials. Specific examples of such materials include a humidity curable resin that begins to cure by contact with moisture, an anaerobic sealant that initiates curing by contact with metal, and the like.

Therefore, the third embodiment of the present invention
An electronic component according to any one of the first or second embodiments of the present invention,
The second material is a humidity curable resin that starts to cure by contact with moisture as the third substance.
It is an electronic component.

  As described above, in the electronic component according to this embodiment, the second material is a humidity curable resin that starts to be cured by contact with moisture as the third substance. Therefore, in the electronic component according to this embodiment, the coating layer is applied to a region where at least one of the lead-free plating layer and the lead-free solder is disposed on the surface of the base material of the terminal included in the electronic component. First, the first material is cured, and then, for example, from the outer surface of the coating layer (that is, the surface opposite to the terminal included in the electronic component) by contact with moisture contained in the air. The second material is gradually cured. That is, in the coating layer according to this embodiment, the ratio of the cured second material gradually increases from the outer surface side of the coating layer in the coating layer as time passes.

  On the other hand, the whisker is not generated at the time when the electronic component is manufactured even in the electronic component according to the present embodiment, and the surface of the base material of the terminal included in the electronic component with the passage of time thereafter. At least one of the lead-free plating layer and the lead-free solder is generated and gradually grows. That is, also in the coating layer according to this embodiment, as described above, the curing of the second material and the generation and growth of whiskers proceed in parallel. Thereby, according to the coating layer which concerns on this embodiment, with the generation | occurrence | production and growth of a whisker, a 2nd material is hardened | cured gradually by contact with a water | moisture content, and a whisker contacts the hardened 2nd material. The growth of whiskers can be more efficiently suppressed.

  In addition to the above, in the electronic component according to the present embodiment, as described above, since the second material is gradually cured by contact with moisture, moisture that has penetrated into the coating layer is polymerized by the second material. Consumed to initiate reaction or crosslinking reaction. This prevents moisture that has penetrated into the coating layer from reaching the lead-free plating layer or lead-free solder on the surface of the base material of the terminals of the electronic component and corroding these metals. can do. In addition, it is possible to suppress the occurrence of whiskers from the lead-free plating layer or lead-free solder disposed on the surface of the base material of the terminal provided in the electronic component.

  Various types of humidity curable resins employed as the second material are known in the art. Specifically, examples of the humidity curable resin include a cyanoacrylate resin, a phenol resin, a silicone resin, and a polyurethane resin.

That is, the electronic component according to the fourth embodiment of the present invention is
An electronic component according to the third embodiment of the present invention,
The humidity curable resin comprises at least one of a cyanoacrylate resin, a phenol resin, a silicone resin, and a polyurethane resin.
It is an electronic component.

  As described above, in the electronic component according to this embodiment, the humidity curable resin includes at least one of a cyanoacrylate resin, a phenol resin, a silicone resin, and a polyurethane resin. That is, in the coating according to this embodiment, the second material may contain only one of a cyanoacrylate resin, a phenol resin, a silicone resin, and a polyurethane resin, or these Two or more kinds of materials may be included.

  On the other hand, as described above, in the coating layer applied to at least one of the lead-free plating layer and the lead-free solder on the surface of the base material of the terminal included in the electronic component according to the present invention, the first As the second material dispersed in one material, a material such as a resin that is cured by a polymerization reaction or a crosslinking reaction initiated by contact with a metal (including metal ions) can also be used. Specific examples of such a material include an anaerobic sealant that initiates curing upon contact with a metal as described above.

Accordingly, the fifth embodiment of the present invention provides:
An electronic component according to any one of the first or second embodiments of the present invention,
The second material is an anaerobic sealant that initiates curing upon contact with a metal as the third substance;
It is an electronic component.

  As described above, in the electronic component according to the present embodiment, the second material is an anaerobic sealant that starts to be cured by contact with a metal as the third substance. Therefore, in the electronic component according to this embodiment, the coating layer is applied to a region where at least one of the lead-free plating layer and the lead-free solder is disposed on the surface of the base material of the terminal included in the electronic component. First, the first material is cured, and then, for example, the coating layer and the electronic component are brought into contact with at least one of the lead-free plating layer and the lead-free solder on the surface of the base material of the terminal included in the electronic component. The second material is gradually cured from the interface with the lead-free plating layer or the lead-free solder disposed on the surface of the base material of the terminal included in the terminal. That is, in the coating layer according to this embodiment, the ratio of the cured second material gradually increases from the interface side of the coating layer inside the coating layer as time passes.

  On the other hand, the whisker is not generated at the time when the electronic component is manufactured even in the electronic component according to the present embodiment, and the surface of the base material of the terminal included in the electronic component with the passage of time thereafter. At least one of the lead-free plating layer and the lead-free solder is generated and gradually grows. That is, also in the coating layer according to this embodiment, as described above, the curing of the second material and the generation and growth of whiskers proceed in parallel. In addition, in the electronic component according to the present embodiment, as described above, the coating layer and the lead-free plating layer disposed on the surface of the base material of the terminal included in the electronic component or the lead-free solder interface The curing of the two materials begins. The interface is exactly where whiskers are generated. Therefore, in the electronic component according to this embodiment, the second material is intensively cured at the location where the whisker is generated, and the second material is gradually cured as the whisker grows. When the whisker comes into contact with the second material thus cured, generation and growth of the whisker can be more efficiently suppressed.

  In addition to the above, in the electronic component according to the present embodiment, the second material not only initiates and progresses by contact with the lead-free plating layer or lead-free solder as described above, but also contacts with the whisker. Curing starts and progresses. That is, in the electronic component according to this embodiment, when the whisker further penetrates into the coating layer according to this embodiment by breaking through the second material cured in the vicinity of the interface where the whisker is generated, Comes into contact with the uncured second material, the uncured second material starts to be cured by contact with the whisker. Thus, in the coating layer according to this embodiment, the hardening of the second material is further promoted by the growth of the whisker. As a result, according to the coating layer according to the present embodiment, the generation and growth of whiskers from the lead-free plating layer and lead-free solder disposed on the surface of the base material of the terminal included in the electronic component are further effective. Can be suppressed.

  Various types of anaerobic sealants employed as the second material are known in the art. Specifically, examples of the humidity curable resin include a vinyl acetate resin, an acrylic resin, a polyamide resin (for example, nylon), and an epoxy resin.

That is, the sixth embodiment of the present invention
An electronic component according to the fifth embodiment of the present invention,
The anaerobic sealant comprises at least one of vinyl acetate resin, acrylic resin, polyamide resin, and epoxy resin;
It is an electronic component.

  As described above, in the electronic component according to this embodiment, the anaerobic sealant is at least one of a vinyl acetate resin, an acrylic resin, a polyamide resin (for example, nylon), and an epoxy resin. Comprising. That is, in the coating according to this embodiment, the second material may contain only one of vinyl acetate resin, acrylic resin, polyamide resin, and epoxy resin, or these Two or more kinds of materials may be included.

  The region where at least one of the lead-free plating layer and the lead-free solder is disposed on the surface of the base material of the terminal included in the electronic component according to the present invention is, as described above, the first material and the second material. It is covered with a coating layer made of the first material in which the second material, which is gradually cured by contact with a third substance different from any other, is dispersed. The second material that is gradually cured by contact with the third substance does not necessarily have to be composed of one kind of material, and is different from the first material and the second material. You may be comprised by the multiple types of material which hardening progresses gradually by contact with a substance. For example, the second material is a resin that cures when a polymerization reaction or crosslinking reaction is initiated by contact with moisture and a resin that cures when a polymerization reaction or crosslinking reaction is initiated by contact with a metal (including metal ions). And a mixture thereof. As a specific example of such a mixture, for example, a mixture of a humidity curable resin that starts curing by contact with moisture and an anaerobic sealant that starts curing by contact with metal can be given.

Accordingly, the seventh embodiment of the present invention provides:
An electronic component according to any one of the first or second embodiments of the present invention,
The second material comprises a humidity curable resin that starts to be cured by contact with moisture as the third substance and an anaerobic sealant that starts to be cured by contact with the metal as the third substance. A mixture,
It is an electronic component.

  As described above, in the electronic component according to the present embodiment, the second material includes a humidity curable resin that starts to be cured by contact with moisture as the third substance, and a metal as the third substance. It is a mixture with the anaerobic sealing agent which starts hardening by contact with. Therefore, in the electronic component according to this embodiment, the coating layer is applied to a region where at least one of the lead-free plating layer and the lead-free solder is disposed on the surface of the base material of the terminal included in the electronic component. First, the first material is cured. Thereafter, for example, one component constituting the second material from the outer surface of the coating layer (that is, the surface opposite to the terminal included in the electronic component) by contact with moisture contained in the air. For example, the coating layer and the electronic component are cured by the contact with at least one of the lead-free plating layer and the lead-free solder on the surface of the base material of the terminal included in the electronic component. The anaerobic sealant, which is the other component constituting the second material, gradually cures from the interface with the lead-free plating layer or lead-free solder disposed on the surface of the base material of the terminal provided in the component. That is, in the coating layer according to this embodiment, the ratio of the cured moisture curable resin gradually increases from the outer surface side of the coating layer in the coating layer as time passes, and the coating layer From the interface side of the layer, the ratio of the cured anaerobic sealant gradually increases.

  On the other hand, the whisker is not generated at the time when the electronic component is manufactured even in the electronic component according to the present embodiment, and the surface of the base material of the terminal included in the electronic component with the passage of time thereafter. At least one of the lead-free plating layer and the lead-free solder is generated and gradually grows. That is, also in the coating layer according to this embodiment, as described above, the curing of the second material and the generation and growth of whiskers proceed in parallel. Thereby, according to the coating layer which concerns on this embodiment, with the generation | occurrence | production and growth of a whisker, a 2nd material is hardened | cured gradually by contact with a water | moisture content, and a whisker contacts the hardened 2nd material. The growth of whiskers can be more efficiently suppressed.

  In addition to the above, in the electronic component according to the present embodiment, as described above, since the humidity curable resin is gradually cured by contact with moisture, the moisture that has entered the coating layer is moisture curable resin. It is consumed to initiate the polymerization reaction and crosslinking reaction. This prevents moisture that has penetrated into the coating layer from reaching the lead-free plating layer or lead-free solder on the surface of the base material of the terminals of the electronic component and corroding these metals. can do. In addition, it is possible to suppress the occurrence of whiskers from the lead-free plating layer or lead-free solder disposed on the surface of the base material of the terminal provided in the electronic component. On the other hand, in the electronic component according to the present embodiment, as described above, whiskers are formed inside the coating layer according to the present embodiment by breaking through the anaerobic sealant cured in the vicinity of the interface where the whisker is generated. When further entering, when the whisker comes into contact with an uncured anaerobic sealant, the uncured anaerobic sealant starts to cure upon contact with the whisker. Thus, in the coating layer which concerns on this embodiment, hardening of an anaerobic sealing agent is further accelerated | stimulated by the growth of a whisker. As a result, according to the coating layer according to the present embodiment, the generation and growth of whiskers from the lead-free plating layer and the lead-free solder disposed on the surface of the base material of the terminal included in the electronic component are even more effective. Can be suppressed.

  As described above, various types of humidity curable resins, which are one component constituting the second material, are known in the technical field. Specifically, examples of the humidity curable resin include a cyanoacrylate resin, a phenol resin, a silicone resin, and a polyurethane resin. In addition, various types of anaerobic sealants that are the other component constituting the second material are known in the technical field. Specifically, examples of the humidity curable resin include a vinyl acetate resin, an acrylic resin, a polyamide resin (for example, nylon), and an epoxy resin.

Accordingly, the eighth embodiment of the present invention provides:
An electronic component according to the seventh embodiment of the present invention,
The humidity curable resin comprises at least one of a cyanoacrylate resin, a phenol resin, a silicone resin, and a polyurethane resin,
The anaerobic sealant comprises at least one of vinyl acetate resin, acrylic resin, polyamide resin, and epoxy resin;
It is an electronic component.

  As described above, in the electronic component according to this embodiment, the humidity curable resin includes at least one of a cyanoacrylate resin, a phenol resin, a silicone resin, and a polyurethane resin. That is, in the coating according to this embodiment, the humidity curable resin that is one component constituting the second material is any one of a cyanoacrylate resin, a phenol resin, a silicone resin, and a polyurethane resin. May be included, or two or more of these materials may be included. Further, as described above, in the electronic component according to this embodiment, the anaerobic sealant is at least one of vinyl acetate resin, acrylic resin, polyamide resin (for example, nylon), and epoxy resin. Comprising one species. That is, in the coating according to the present embodiment, the anaerobic sealant as the other component constituting the second material is any one of vinyl acetate resin, acrylic resin, polyamide resin, and epoxy resin. It may contain only seeds, or it may contain two or more of these materials.

  By the way, in this technical field, for example, moisture in the air penetrates into the interior of the electronic component, resulting in poor insulation between terminals of various circuit elements constituting the electronic component and corrosion of metal parts such as the terminal. For the purpose of avoiding problems such as poor conduction, for example, the vicinity of the terminal portion of an electronic component or the entire electronic component is widely sealed with a moisture-proof coating layer. Therefore, the coating layer covering at least one region of the lead-free plating layer and the lead-free solder on the surface of the base material of the terminal included in the electronic component according to the present invention is a hollow particle that suppresses whisker growth. If not only the role of dispersing but also the role of the moisture-proof coating layer can be achieved, it is possible to avoid complication of the manufacturing process of the electronic component.

Accordingly, the ninth embodiment of the present invention provides:
An electronic component according to any one of the first to eighth embodiments of the present invention,
The first material is a moisture-proof material;
It is an electronic component.

  As described above, in the electronic component according to this embodiment, the first material is a moisture-proof material. Therefore, in the electronic component according to the present embodiment, in the application process of the moisture-proof coating layer that is widely performed in the manufacturing process of the electronic component according to the technical field as described above, instead of the moisture-proof coating layer according to the prior art. The application of the coating layer according to the present invention not only complicates the manufacturing process of the electronic component, but also imparts moisture resistance to the electronic component, and also has the effect of suppressing the growth of whiskers as described above. Can be obtained.

  By the way, in the said technical field, as a material which forms the above-mentioned moisture-proof coating layer, thermosetting resins, such as an epoxy resin, polyolefin resin, acrylic resin, polyurethane resin, silicone resin, etc. are mentioned, for example. Can do. The hardness of these resin coating layers can be adjusted, for example, by adjusting the amount of the crosslinking agent added to these materials. However, as described above, in the first material and the second material constituting the coating layer according to the present invention, it is more desirable that the hardness of the first material is smaller than the hardness of the second material. Therefore, as the first material included in the coating layer according to the present invention, for example, a relatively small hardness such as a polyolefin resin, an acrylic resin, a polyurethane resin, and a silicone resin can be easily achieved. It is desirable to use materials.

Accordingly, the tenth embodiment of the present invention provides:
An electronic component according to the ninth embodiment of the present invention,
The moisture-proof material comprises at least one of a polyolefin resin, an acrylic resin, a polyurethane resin, and a silicone resin.
It is an electronic component.

  As described above, in the electronic component according to this embodiment, the first material includes at least one of a polyolefin resin, an acrylic resin, a polyurethane resin, and a silicone resin. These materials are widely used as materials for forming the moisture-proof coating layer as described above in the technical field. Therefore, the coating layer that covers at least a region where at least one of the lead-free plating layer and the lead-free solder is provided on the surface of the base material of the terminal included in the electronic component according to the present embodiment has only a role of suppressing whisker growth. In addition, it can also serve as a moisture-proof coating layer as described above. Furthermore, these materials can easily achieve a relatively small hardness as described above. Therefore, it is more desirable to use these materials as the first material included in the coating layer according to the present invention. In addition, the hardness after hardening of the 1st material which consists of these materials can be adjusted, for example by adjusting the quantity of the crosslinking agent added to these materials. In addition, as described above, the first material included in the coating layer according to this embodiment may be composed of only one of a polyolefin resin, an acrylic resin, a polyurethane resin, and a silicone resin. Alternatively, two or more of these materials may be included.

  Although several embodiments of the electronic component according to the present invention have been described above, the scope of the present invention is not limited to these electronic components, and the manufacturing method of these electronic components is also within the scope of the present invention. include. About the manufacturing method of these electronic components, the matter that is clear from the description of the electronic component according to each embodiment described so far will not be described here again, and the matter that needs to be newly described Only explained. Several embodiments of the method for manufacturing an electronic component according to the present invention will be listed below.

First, the eleventh embodiment of the present invention is
A method of manufacturing an electronic component comprising a terminal having at least one of a lead-free plating layer and a lead-free solder on the surface of a base material,
Covering at least an exposed surface of the lead-free plating layer and the lead-free solder with a coating layer;
Including
The coating layer comprises a first material and a second material dispersed in the first material;
The second material is a material that starts curing by contact with a third substance different from any of the first material and the second material.
It is a manufacturing method of an electronic component.

Next, a twelfth embodiment of the present invention includes
An electronic component manufacturing method according to the eleventh embodiment of the present invention, comprising:
The hardness of the second material after curing is greater than the hardness of the first material after curing;
It is a manufacturing method of an electronic component.

The thirteenth embodiment of the present invention provides
An electronic component manufacturing method according to any one of the eleventh or twelfth embodiments of the present invention,
The second material is a humidity curable resin that starts to cure by contact with moisture as the third substance.
It is a manufacturing method of an electronic component.

Furthermore, the fourteenth embodiment of the present invention provides
An electronic component manufacturing method according to the thirteenth embodiment of the present invention, comprising:
The humidity curable resin comprises at least one of a cyanoacrylate resin, a phenol resin, a silicone resin, and a polyurethane resin.
It is a manufacturing method of an electronic component.

Still further, the fifteenth embodiment of the present invention provides:
An electronic component manufacturing method according to any one of the eleventh or twelfth embodiments of the present invention,
The second material is an anaerobic sealant that initiates curing upon contact with a metal as the third substance;
It is a manufacturing method of an electronic component.

Then, the sixteenth embodiment of the present invention is
An electronic component manufacturing method according to the fifteenth embodiment of the present invention, comprising:
The anaerobic sealant comprises at least one of vinyl acetate resin, acrylic resin, polyamide resin, and epoxy resin;
It is a manufacturing method of an electronic component.

Next, the seventeenth embodiment of the present invention provides
An electronic component manufacturing method according to any one of the eleventh or twelfth embodiments of the present invention,
The second material comprises a humidity curable resin that starts to be cured by contact with moisture as the third substance and an anaerobic sealant that starts to be cured by contact with the metal as the third substance. A mixture,
It is a manufacturing method of an electronic component.

The eighteenth embodiment of the present invention provides
An electronic component manufacturing method according to the seventeenth embodiment of the present invention, comprising:
The humidity curable resin comprises at least one of a cyanoacrylate resin, a phenol resin, a silicone resin, and a polyurethane resin,
The anaerobic sealant comprises at least one of vinyl acetate resin, acrylic resin, polyamide resin, and epoxy resin;
It is a manufacturing method of an electronic component.

Furthermore, the nineteenth embodiment of the present invention provides
An electronic component manufacturing method according to any one of the eleventh to eighteenth embodiments of the present invention,
The first material is a moisture-proof material;
It is a manufacturing method of an electronic component.

Still further, the twentieth embodiment of the present invention provides:
An electronic component manufacturing method according to the nineteenth embodiment of the present invention, comprising:
The moisture-proof material comprises at least one of a polyolefin resin, an acrylic resin, a polyurethane resin, and a silicone resin.
It is a manufacturing method of an electronic component.

  By the way, a method of applying the coating layer according to the present invention to at least one of the lead-free plating layer and the lead-free solder on the surface of the base material of the terminal included in the electronic component is a specific application method. It is not limited to these, and can be appropriately selected from various coating methods widely used in the technical field. Examples of such an application method include a spray coating method and a dip coating method.

That is, the twenty-first embodiment of the present invention
An electronic component manufacturing method according to any one of the eleventh to twentieth embodiments of the present invention,
Covering at least the exposed surface of the lead-free plating layer and the lead-free solder with the coating layer by a spray coating method,
It is a manufacturing method of an electronic component.

  As described above, in the method of manufacturing an electronic component according to this embodiment, a spray coating method is employed when at least the exposed surface of the lead-free plating layer and the lead-free solder is covered with the coating layer. As is well known to those skilled in the art, the spray coating method uses a spray (atomizer) to change the liquid forming the coating layer into a state of mist, foam, etc. with compressed air or high-pressure gas, etc. It is the method of spraying with respect to. The compressed air, high-pressure gas, or the like can be supplied by, for example, a cylinder filled with compressed air, high-pressure gas, or the like, or can be supplied by a compressor such as an electric pump.

  In the method for manufacturing an electronic component according to this embodiment, the first material and the second material constituting the coating layer according to the present invention may be mixed in advance before the application, or the application of the application You may mix at the time or just before the said application | coating.

On the other hand, the twenty-second embodiment of the present invention
An electronic component manufacturing method according to any one of the eleventh to twentieth embodiments of the present invention,
By the dip coating method, at least the exposed surface of the lead-free plating layer and the lead-free solder is covered with the coating layer,
It is a manufacturing method of an electronic component.

  As described above, in the method of manufacturing an electronic component according to this embodiment, a dip coating method is employed when at least the exposed surfaces of the lead-free plating layer and the lead-free solder are covered with the coating layer. As is well known to those skilled in the art, the dip coating method is a liquid that adheres to the surface of an application object by immersing the application object in a liquid that forms a coating layer and pulling up the application object from the liquid. This is a method of forming a film. In the coating method, for example, the viscosity of the liquid forming the coating layer, the surface tension, and the flow of the liquid adhering to the surface of the coating object due to gravity flow are adjusted to adjust the speed of lifting the coating object from the liquid. Thus, the thickness of the liquid film attached to the surface of the application object can be controlled.

  In the method for manufacturing an electronic component according to this embodiment, the first material and the second material constituting the coating layer according to the present invention may be mixed in advance before the application, or the application of the application You may mix at the time or just before the said application | coating.

  As described above, according to the electronic component and the method for manufacturing the electronic component according to various embodiments of the present invention, the electronic component including the terminal having at least one of the lead-free plating layer and the lead-free solder on the surface of the base material. The lead-free plating layer and the lead-free solder at least the exposed surface is a coating layer comprising a first material and a second material dispersed in the first material, wherein the second material is the first material. Generation and growth of whiskers from the lead-free plating layer and the lead-free solder by covering with a coating layer that is a material that begins to harden upon contact with a third substance different from either the first material or the second material Accordingly, the second material is gradually cured, and the whisker that has entered the coating layer comes into contact with the cured second material so that the whisker grows more efficiently. It can be suppressed to.

  Several embodiments of the present invention will be described below with reference to the accompanying drawings. However, the following description is for illustrative purposes only, and the scope of the present invention should not be construed as being limited to the following description.

1. Suppression of whisker growth by coating according to the present invention (1)
FIG. 1 is a schematic diagram for explaining the occurrence of whiskers on the surface of a terminal provided in an electronic component according to one embodiment of the present invention as described above. In FIG. 1, (a), (b), and (c) represent that time has passed in this order. More specifically, FIG. 1A shows that the coating layer 10 according to the present embodiment is formed on a lead-free plating layer or lead-free solder 43 provided on the surface of the base material of the terminal of the electronic component. This corresponds to the state immediately after the placement. As shown in FIG. 1A, the coating layer 10 includes a first material 11 and a second material 12 dispersed in the first material 11. In the present embodiment, a humidity curable resin that starts curing upon contact with moisture is used as the second material 12. Further, in this embodiment, the circular (spherical) domains formed by the second material 12 are dispersed in the shape of sea islands in the first material 11, but in the first material in the coating layer according to the present invention. The dispersion form of the second material is not limited to such a form.

  Next, in FIG. 1B, time has elapsed from the state shown in FIG. 1A, and the moisture 14 in the air is on the outer surface side of the coating layer 10 according to this example (upper side in FIG. 1). To the inside of the coating layer 10, and accordingly, the domain of the second material 12 existing in the vicinity of the outer surface of the coating layer 10 has started to be cured. In FIG. 1, a portion indicated by a black circle represents a domain of the second material 12 cured by contact with the moisture 14. A straight line connecting the black circles indicates that the substance (monomer) constituting the second material 12 has started the polymerization reaction or the crosslinking reaction by contact with the moisture 14 to form the network 13. Further, as shown in FIG. 1B, whiskers 21 are generated from the lead-free plating layer or the lead-free solder 43 at this time.

  Next, in FIG. 1C, the time elapses further from the state shown in FIG. 1B, and the curing of the second material 12 by the contact with the moisture 14 that has entered the coating layer 10 further proceeds. The whisker 21 generated from the lead-free plating layer or the lead-free solder 43 further grows and further enters the inside of the coating layer 10, and represents a state in which the whisker 21 tries to contact the domain of the cured second material 12. As shown in FIG. 1C, at this point, the second material 12 is further cured, and the domain of the cured second material 12 is further increased. It becomes difficult to grow further in contact with the domain.

  As described above, in the electronic component according to the present embodiment, the whisker 21 generated from the lead-free plating layer or the lead-free solder 43 disposed on the surface of the base material of the terminal included in the electronic component grows, When entering the inside of the coating layer 10, hardening of the domains of the second material 12 dispersed in the first material 11 proceeds by contact with the moisture 14 that has entered the inside of the coating layer 10. It prevents the whisker 21 from growing further. Thereby, in the electronic component according to the present embodiment, the whisker 21 generated from the lead-free plating layer or the lead-free solder 43 formed on the surface of the terminal included in the electronic component grows to the outside of the coating layer 10. It is possible to effectively suppress problems such as a short circuit (short circuit) between the terminals of the electronic component as described above. In addition, in the present embodiment, as described above, the moisture 14 that has entered the coating layer 10 starts the polymerization reaction and the crosslinking reaction of the second material 12 dispersed in the first material 11. Is consumed. Thereby, it can suppress that the water | moisture content 14 which penetrate | invaded the inside of the coating layer 10 arrives at a lead free plating layer and the lead free solder 43, and corrodes these metals. In addition, the generation of whiskers 21 from the lead-free plating layer and the lead-free solder 43 can be suppressed.

2. Suppression of whisker growth by coating according to the present invention (2)
FIG. 2 is a schematic diagram for explaining the occurrence of whiskers on the surface of the terminal provided in the electronic component according to another embodiment of the present invention as described above. In FIG. 2, (a), (b), and (c) represent that time has passed in this order. More specifically, FIG. 2A shows that the coating layer 10 according to this embodiment is formed on a lead-free plating layer or lead-free solder 43 provided on the surface of the base material of the terminal of the electronic component. This corresponds to the state immediately after the placement. As shown in FIG. 2A, the coating layer 10 includes a first material 11 and a second material 12 dispersed in the first material 11. In the present embodiment, an anaerobic sealant that starts curing upon contact with a metal is employed as the second material 12. Further, in this embodiment, the circular (spherical) domains formed by the second material 12 are dispersed in the shape of sea islands in the first material 11, but in the first material in the coating layer according to the present invention. The dispersion form of the second material is not limited to such a form.

  Next, FIG. 2B shows the second material 12 existing in the vicinity of the interface with the lead-free plating layer of the coating layer 10 or the lead-free solder 43 after a lapse of time from the state shown in FIG. This represents a state in which the domain has started to harden. In FIG. 2, a portion indicated by a black circle represents a domain of the second material 12 cured by contact with the lead-free plating layer or the lead-free solder 43. Further, the straight line connecting the black circles starts the polymerization reaction or the crosslinking reaction when the substance (monomer) constituting the second material 12 contacts the lead-free plating layer or the lead-free solder 43, and the network 13 Represents the formation of As described above, in the coating layer 10 according to the present embodiment, the contact with the lead-free plating layer or the lead-free solder 43 causes an emphasis in the vicinity of the interface between the coating layer 10 and the lead-free plating layer or the lead-free solder 43. In particular, since the hardening of the second material 12 proceeds, the generation of the whisker 21 from the lead-free plating layer or the lead-free solder 43 is suppressed. However, as shown in FIG. 2B, whiskers 21 can be generated from the lead-free plating layer or the lead-free solder 43 in the region where the domain of the cured second material 12 is not formed. Even in the region where the domain of the cured second material 12 is formed, the whisker 21 may be generated from the lead-free plating layer or the lead-free solder 43 and may enter the inside of the coating layer 10.

  Next, in FIG. 2C, as time elapses further from the state shown in FIG. 2B, the curing of the second material 12 in the coating layer 10 further progresses, and a lead-free plating layer or lead-free The whisker 21 generated from the solder 43 further grows, further enters the inside of the coating layer 10, contacts the domain of the uncured second material 12, and represents a state where the domain of the second material 12 is cured. . As shown in FIG. 2 (c), at this point, the second material 12 is further cured by contact with the lead-free plating layer or the lead-free solder 43, and enters the coating layer 10 as described above. The second material 12 is further cured by contact with the whisker 21. As a result, at this point, since the domains of the cured second material 12 are further increased, the whisker 21 is constrained by the domains of the cured second material 12 and is difficult to grow further.

  As described above, in the electronic component according to the present embodiment, in the vicinity of the interface with the coating layer 10 with the lead-free plating layer or the lead-free solder 43 disposed on the surface of the base material of the terminal included in the electronic component. Due to the hardening of the second material 12, the generation of the whisker 21 from the lead-free plating layer or the lead-free solder 43 is suppressed. In addition, in the electronic component according to the present embodiment, even if the whisker 21 generated from the lead-free plating layer or the lead-free solder 43 grows and enters the inside of the coating layer 10, Contact with the domains of the uncured second material 12 dispersed in the second material 12 begins to cure, preventing further growth of the whisker 21. Thereby, in the electronic component according to the present embodiment, the whisker 21 generated from the lead-free plating layer or the lead-free solder 43 formed on the surface of the terminal included in the electronic component grows to the outside of the coating layer 10. It is possible to effectively suppress problems such as a short circuit (short circuit) between the terminals of the electronic component as described above.

3. Coating application method (1) according to the present invention
FIG. 3 is a schematic diagram for explaining a coating layer applying method in the method of manufacturing an electronic component according to one embodiment of the present invention as described above. More specifically, FIG. 3 shows an embodiment of the present invention in which at least an exposed surface of a lead-free plating layer and lead-free solder disposed on a surface of a base material of a terminal included in an electronic component is formed by spray coating. A procedure for coating with the coating layer according to the embodiment will be schematically described. As shown in FIG. 3, in the method of manufacturing an electronic component according to this embodiment, an electronic component 40 including a substrate 44 on which a circuit element 41 including a terminal 42 is disposed is ejected from a spray (atomizer) 33. The mist-like coating material 34 is covered.

  In the method for manufacturing an electronic component according to this embodiment, the liquid 31 containing the first material and the liquid 32 containing the second material constituting the coating layer according to this embodiment are mixed and ejected from the spray (sprayer) 35. Thus, the electronic component 40 is coated with the mist-like coating material 34 including the first material and the second material. Thereby, in the manufacturing method of the electronic component which concerns on a present Example, the mixing of the liquid 31 containing a 1st material and the liquid 32 containing a 2nd material, and the mist-like coating material containing a 1st material and a 2nd material 34 spraying to the electronic component 40 is performed simultaneously.

  FIG. 4 is a schematic diagram showing the electronic component 40 covered with the coating layer 10 according to the present embodiment as described above. That is, FIG. 4 is a schematic diagram showing the coating layer applied to the electronic component by the method for manufacturing the electronic component according to one embodiment of the present invention as described above. As shown in FIG. 4, in the electronic component 40 including the substrate 44 on which the circuit element 41 including the terminal 42 is disposed, the entire circuit element 41 including the terminal 42 is formed by the coating layer 10 according to the present embodiment. Covered. Therefore, in the electronic component 40, as described with reference to FIGS. 1 and 2, the second material dispersed in the first material contained in the coating layer 10 is gradually cured, so that The generation and growth of whiskers from the lead-free plating layer or lead-free solder formed on the surface is suppressed. Thereby, also in the electronic component 40 manufactured by the manufacturing method according to the present embodiment, the whisker grows to the outside of the coating layer 10, and there is a problem such as a short circuit between the terminals of the electronic component as described above. Can be effectively suppressed.

4). Coating method according to the present invention (2)
FIG. 5 is a schematic diagram for explaining a coating layer coating method in the method of manufacturing an electronic component according to another embodiment of the present invention as described above. More specifically, FIG. 5 shows an embodiment of the present invention in which at least an exposed surface of a lead-free plating layer and lead-free solder disposed on a surface of a base material of a terminal included in an electronic component is formed by dip coating. A procedure for coating with the coating layer according to the embodiment will be schematically described. As shown in FIG. 5, in the method for manufacturing an electronic component according to this embodiment, an electronic component 40 including a substrate 44 on which a circuit element 41 including a terminal 42 is disposed is accommodated in a coating liquid bath 52. The first material and the second material adhering to the surface of the electronic component 40 are dipped in the liquid 51 containing the first material and the second material and the electronic component 40 is pulled up from the liquid 51 containing the first material and the second material. The coating layer according to the present invention is formed by forming a coating of the liquid 51 containing two materials and curing the coating (for example, by evaporation of the solvent contained in the liquid 51 containing the first material and the second material). It is formed on the surface of the electronic component 40. As described above, in the coating method, for example, the viscosity and surface tension of the liquid 51 including the first material and the second material, and the liquid 51 including the first material and the second material attached to the surface of the electronic component 40. The thickness of the film formed on the surface of the electronic component 40 can be controlled by adjusting the speed at which the electronic component 40 is pulled up from the liquid 51 containing the first material and the second material in consideration of the downward flow due to gravity. it can.

  In addition, according to the said application | coating method, as mentioned above, the whole electronic component 40 including the board | substrate 44 with which the circuit element 41 provided with the terminal 42 was arrange | positioned is covered with the coating layer which concerns on a present Example. Accordingly, also in this embodiment, as described with reference to FIGS. 1 and 2, the second material dispersed in the first material included in the coating layer according to the present invention is gradually cured, Generation and growth of whiskers from the lead-free plating layer or lead-free solder formed on the surface of the terminal 42 are suppressed. Thereby, also in the electronic component 40 manufactured by the manufacturing method according to the present embodiment, the whisker grows to the outside of the coating layer according to the present invention, and the short circuit (short) between the terminals of the electronic component as described above. The occurrence of such problems can be effectively suppressed.

5. Evaluation of Whisker Growth Suppression Effect by Coating According to the Present Invention (1)
(1) Coating material for evaluation sample As described above, for example, a moisture-proof material can be used as the first material according to the present invention, and examples of the moisture-proof material include polyolefin resins and acrylics. Resin, polyurethane resin, silicone resin and the like can be used. In this example, an acrylic resin was used as the first material constituting the coating layer as various evaluation samples. On the other hand, as described above, for example, a humidity curable resin can be used as the second material according to the present invention. Examples of the humidity curable resin include a cyanoacrylate resin, a phenol resin, and a silicone resin. Resins, polyurethane resins, and the like can be used. In this example, a cyanoacrylate resin was used as the second material constituting the coating layer as various evaluation samples. In addition, an acrylic resin used as a general moisture-proof coating layer was adopted as the first material, and a comparative sample was prepared as a reference standard in which the second material was not blended at all. Furthermore, a further comparative sample was prepared without using any first material and using only the cyanoacrylate resin as the second material. Details of the various samples for evaluation will be described in detail below with reference to Table 1.

(2) Preparation of sample for evaluation As shown in Table 1, in the sample for evaluation according to Comparative Example 1 as a control sample, an acrylic resin was adopted as the first material, and no second material was blended. It was. On the other hand, in the samples for evaluation according to Examples 1 to 4 and Comparative Example 2, an acrylic resin was employed as the first material, and a cyanoacrylate resin was employed as the second material. In these evaluation samples, the blending ratio [% by mass] of the second material in the entire coating material (that is, the sum of the first material and the second material) is 20% by mass, 40% by mass, and 60%, respectively. The mass%, 80 mass%, and 100 mass% were set.

  Various coating materials were prepared by mixing the above-described materials, and applied to an electronic component having a terminal having a lead-free plating layer on the surface of the base material. As a method for applying various coating materials, for example, a spray coating method, a dip coating method, or the like can be employed as described above. In this example, various coating materials were applied to the electronic component by spray coating, and then the coating layer was cured by drying at 80 ° C. for 30 minutes or more.

(3) Accelerated aging treatment of evaluation sample The various evaluation samples prepared as described above were allowed to stand for 200 hours at a temperature of 85 ° C and a relative humidity of 85%, and then a temperature of 25 ° C and 50%. It was exposed for 5 cycles to the environmental change of standing for 24 hours at relative humidity.

(4) Analysis of evaluation sample For each of the evaluation samples after the accelerated degradation test, the surface of the coating layer in each evaluation sample was observed with an electron microscope (SEM), and the surface penetrated through the coating layer. The whiskers protruding in the area were observed, and the number of whiskers observed in a certain area was counted. Moreover, the presence or absence of the crack (crack) in the surface of the coating layer in each sample for evaluation was investigated visually. These analysis results are listed in Table 1 below together with the material configurations of various evaluation samples. Moreover, the result of having plotted the number of the whisker detected in the said SEM observation with respect to the compounding ratio of the 2nd material in a coating layer is shown in FIG. That is, FIG. 6 is a graph showing the relationship between the number of whiskers detected and the blending ratio of the second material in the coating layer according to one embodiment of the present invention as described above.

(5) Summary As shown in Table 1, Example 1 having a coating layer containing 20% by mass, 40% by mass, 60% by mass, and 80% by mass of the cyanoacrylate resin employed as the second material, respectively. In the evaluation samples according to 2, 3, and 4, neither whisker penetration into the surface of the coating layer nor cracking on the surface of the coating layer was observed. That is, in the evaluation samples according to Examples 1 to 4, whisker growth was effectively suppressed without sacrificing moisture resistance.

  In addition to the above, in the samples for evaluation according to Examples 1, 2, 3, and 4, as described above, the cyanoacrylate resin employed as the second material is gradually cured by contact with moisture. The water that has entered the coating layer is consumed for initiating the polymerization reaction or the crosslinking reaction of the second material. This prevents moisture that has entered the coating layer from reaching the lead-free plating layer or lead-free solder disposed on the surface of the base material of the terminal of the electronic component and corroding these metals. be able to. In addition, it is possible to suppress the occurrence of whiskers from the lead-free plating layer or lead-free solder disposed on the surface of the base material of the terminal provided in the electronic component.

  On the other hand, in the sample for evaluation according to Comparative Example 1 as a reference having a coating layer composed only of the acrylic resin employed as the first material, no cracks were observed on the surface of the coating layer, but the surface of the coating layer Ten whiskers protruding in the area were recognized per certain area. This is probably because the evaluation sample according to Comparative Example 1 did not contain the second material, and thus could not suppress the growth of whiskers that entered the coating layer.

  On the contrary, in the sample for evaluation according to Comparative Example 2 having the coating layer composed only of the cyanoacrylate resin adopted as the second material, three whiskers protruding on the surface of the coating layer were recognized per certain area, and Cracks on the surface of the coating layer were also observed. This is because, in the sample for evaluation according to Comparative Example 5, since the coating layer is constituted only by the second material, the coating layer is hard and lacks flexibility, and the coating layer and the electronic component in the above-described accelerated deterioration treatment It is considered that the coating layer was cracked due to the difference in coefficient of thermal expansion from the terminal of this, and as a result, the function of suppressing the growth of whiskers was also lowered.

  As described above, in an electronic component including a terminal having at least one of a lead-free plating layer and a lead-free solder on a surface of a base material, at least an exposed surface of the lead-free plating layer and the lead-free solder is formed on the first material. And a second material dispersed in the first material, wherein the second material initiates curing upon contact with a third substance that is different from either the first material or the second material. Covering with a coating layer, which is a material (in this embodiment, a humidity curable resin), is generated from the lead-free plating layer and the lead-free solder without sacrificing moisture resistance due to cracking of the coating layer. It was confirmed that whisker growth can be effectively suppressed.

  In addition, in the material structure employ | adopted in the present Example, from the said evaluation result, the suitable mixture rate of the 2nd material in the said coating layer is with respect to the sum of the 1st material and 2nd material which comprise a coating layer. Although it was judged that it was 20 mass% or more and 80 mass% or less, the range of the said suitable mixture rate is not universal. That is, the suitable blending ratio of the second material in the coating layer varies depending on various conditions such as the type of material employed as the first material and the second material constituting the coating layer and the usage environment of the electronic component. However, the suitable blending ratio of the second material in the coating layer is, for example, the kind of material employed as the first material and the second material constituting the coating layer, the usage environment of the electronic component, and the like when the present invention is applied. It can be appropriately determined according to various conditions.

6). Evaluation of Whisker Growth Suppression Effect by Coating According to the Present Invention (2)
(1) Coating material for evaluation sample As described above, for example, a moisture-proof material can be used as the first material according to the present invention, and examples of the moisture-proof material include polyolefin resins and acrylics. Resin, polyurethane resin, silicone resin and the like can be used. In this example, an acrylic resin was used as the first material constituting the coating layer as various evaluation samples. On the other hand, as described above, as the second material according to the present invention, for example, an anaerobic sealant can be used. Examples of the anaerobic sealant include a vinyl acetate resin, an acrylic resin, Polyamide resins and epoxy resins can be used. In this example, vinyl acetate resin was employed as the second material constituting the coating layer as various evaluation samples. In addition, an acrylic resin used as a general moisture-proof coating layer was adopted as the first material, and a comparative sample was prepared as a reference standard in which no second material was blended. In addition, a further comparative sample was prepared, in which the first material was not blended at all and only the vinyl acetate resin as the second material was used. Further, various samples for evaluation using inorganic filler as the second material instead of the vinyl acetate resin were also prepared. Furthermore, a further comparative sample using only an epoxy resin which is a hard resin was also prepared. Details of the various samples for evaluation will be described in detail below with reference to Table 1.

(2) Preparation of sample for evaluation As shown in Table 1, in the sample for evaluation according to Comparative Example 1 as a control sample, an acrylic resin was adopted as the first material, and no second material was blended. It was. On the other hand, in the evaluation samples according to Examples 1 to 3 and Comparative Examples 2 and 3, an acrylic resin was adopted as the first material, and a vinyl acetate resin was adopted as the second material. In these evaluation samples, the blending ratio [% by mass] of the second material in the entire coating material (that is, the sum of the first material and the second material) is 20% by mass, 40% by mass, and 60%, respectively. The mass%, 80 mass%, and 100 mass% were set.

  On the other hand, in the sample for evaluation which concerns on the comparative example 4, it replaced with vinyl acetate type resin, the inorganic filler was employ | adopted as a 2nd material, and the coating material mix | blended with the said 1st material was used. In the sample for evaluation according to Comparative Example 3, the blending ratio [% by mass] of the inorganic filler as the second material with respect to the entire coating material (that is, the sum of the first material and the inorganic filler as the second material) is It was 50 mass%. Furthermore, in the evaluation sample according to Comparative Example 5, as described above, only an epoxy resin that is a hard resin was used.

  Various coating materials were prepared by mixing the above-described materials, and applied to an electronic component having terminals having a lead-free plating layer and lead-free solder on the surface of the base material. As a method for applying various coating materials, for example, a spray coating method, a dip coating method, or the like can be employed as described above. In this example, various coating materials were applied to the electronic component by spray coating, and then the coating layer was cured by drying at 80 ° C. for 30 minutes or more.

(3) Accelerated aging treatment of evaluation sample The various evaluation samples prepared as described above were allowed to stand for 200 hours at a temperature of 85 ° C and a relative humidity of 85%, and then a temperature of 25 ° C and 50%. It was exposed for 5 cycles to the environmental change of standing for 24 hours at relative humidity.

(4) Analysis of evaluation sample For each of the evaluation samples after the accelerated degradation test, the surface of the coating layer in each evaluation sample was observed with an electron microscope (SEM), and the surface penetrated through the coating layer. The whiskers protruding in the area were observed, and the number of whiskers observed in a certain area was counted. Moreover, the hardening state of the coating layer in each sample for evaluation was observed visually. Furthermore, the presence or absence of a crack (crack) on the surface of the coating layer in each sample for evaluation was examined visually. Furthermore, the influence on the peripheral member of the coating layer in each evaluation sample was also observed visually.

  These analysis results are listed in Table 2 below together with the material configurations of the various samples for evaluation. For the samples for evaluation according to Comparative Examples 1 and 2 and Examples 1 to 3, the results of plotting the number of whiskers detected in the SEM observation against the blending ratio of the second material in the coating layer are shown in FIG. Shown in That is, as described above, FIG. 7 is a graph showing the relationship between the number of whiskers detected and the blending ratio of the second material in the coating layer according to another embodiment of the present invention.

(5) Summary As shown in Table 2, Examples 1 and 2 having coating layers containing 20% by mass, 40% by mass, and 60% by mass of the vinyl acetate resin employed as the second material, respectively. In the evaluation sample according to No. 3, whisker penetration through the surface of the coating layer was not observed at all, or was acceptable (less than 2). Moreover, in these samples for evaluation, no cracks in the coating layer were observed. That is, in the samples for evaluation according to Examples 1 to 3, whisker growth was effectively suppressed without sacrificing moisture resistance. However, among these evaluation samples, the coating rate of the vinyl acetate resin as the second material is the highest (that is, 60% by mass). It was sufficient and a gel-like coating layer was formed, but no influence on peripheral members such as contamination due to dripping was observed.

  In the evaluation samples according to Examples 1, 2, and 3, as described above, the vinyl acetate resin employed as the second material is the base material of the terminal provided in the electronic component immediately after the coating layer is applied. Curing is started by contact with the lead-free plating layer and lead-free solder disposed on the surface, and the generation of whiskers from the lead-free plating layer and lead-free solder is suppressed. In addition to this, in the samples for evaluation according to Examples 1, 2, and 3, as described above, whiskers are generated from the lead-free plating layer and the lead-free solder, and the second material is cured as described above. When the whisker comes into contact with the uncured second material dispersed in the coating layer even if it breaks through the anaerobic sealant and enters the coating layer, the uncured second material is brought into contact with the whisker. Curing begins. Thus, in the samples for evaluation according to Examples 1, 2, and 3, as described above, the curing of the anaerobic sealant is further promoted with the growth of the whiskers, and the whisker suppressing effect is maintained over a long period of time. Maintained over time. As a result, in the samples for evaluation according to Examples 1, 2, and 3, the generation and growth of whiskers from the lead-free plating layer or lead-free solder disposed on the surface of the base material of the terminal included in the electronic component Further, it can be further effectively suppressed.

  On the other hand, in the evaluation sample according to Comparative Example 1 as a reference having a coating layer composed only of an acrylic resin employed as the first material, the cured state of the coating layer is good and cracks in the coating layer and peripheral members 12 whisker protruding on the surface of the coating layer per certain area was recognized. This is because, in the sample for evaluation according to Comparative Example 1, since the second material is not blended, a whisker from a lead-free plating layer or a lead-free solder disposed on the surface of the base material of the terminal included in the electronic component It is considered that the generation and growth of sucrose could not be suppressed.

  Conversely, in the sample for evaluation according to Comparative Example 2 having a coating layer containing 80% by mass of the vinyl acetate resin employed as the second material, whiskers protruding on the surface of the coating layer were not recognized, The coating layer was insufficiently cured, and contamination of peripheral members due to dripping was observed. This is because, in the sample for evaluation according to Comparative Example 2, an anaerobic sealant that is difficult to be cured by contact with air is excessively blended as the second material, so that the coating layer can be cured. It is thought that there was not.

  Furthermore, the evaluation sample according to Comparative Example 3 having a coating layer containing 100% by mass of the vinyl acetate resin employed as the second material (that is, containing no acrylic resin employed as the first material). The coating layer was not sufficiently cured, and whiskers protruding on the surface of the coating layer could not be observed. Further, as in the evaluation sample according to Comparative Example 2, contamination of peripheral members due to dripping was observed.

  In the sample for evaluation according to Comparative Example 4 having the coating layer containing 50% by mass of the inorganic filler adopted as the second material, the cured state of the coating layer is good and the whisker protruding to the surface of the coating layer is constant. 12 lines were recognized per area. Although two whiskers exceeding the allowable range (less than two) were observed on the surface of the coating layer, some whisker suppressing effects were exhibited. However, in the evaluation sample according to Comparative Example 4, the occurrence of cracks in the coating layer was observed. That is, it was suggested that when an inorganic filler is employed as the second material, it is difficult to achieve both whisker suppression performance and moisture proof performance. This is presumably because the inorganic filler blended in a large amount in the evaluation sample according to Comparative Example 4 acted as a solid content serving as a starting point for cracking of the coating layer. As described above, in the sample for evaluation according to Comparative Example 4 in which the crack of the coating layer occurred, there is a concern that it is difficult to maintain the whisker suppression exchange equivalent to that immediately after the coating layer is applied even after the lapse of time.

  Moreover, in the sample for evaluation which has the coating layer which consists only of epoxy resin which is hard resin, the penetration of the whisker to the surface of a coating layer is not recognized at all, and the hardening state of a coating layer is also favorable. there were. However, in the evaluation sample according to Comparative Example 5, cracking of the coating layer was observed. In addition, in the sample for evaluation according to Comparative Example 5, cracks were observed in the lead-free solder disposed on the surface of the base material of the terminal included in the electronic component. This is because, in the sample for evaluation according to Comparative Example 5, since the coating layer is constituted only by the epoxy resin that is a hard resin, the coating layer is hard and lacks flexibility, and the coating in the accelerated deterioration treatment described above is performed. Due to the difference in coefficient of thermal expansion between the layer and the terminal of the electronic component, a very large stress was generated between the coating layer and the terminal of the electronic component, the coating layer cracked, and cracks occurred in the lead-free solder It is considered a thing. As a result, in the sample for evaluation according to Comparative Example 5, problems such as poor conduction and disconnection in electronic parts are concerned, and cracking of the coating layer has occurred, so that whisker suppression equivalent to that immediately after application of the coating layer has occurred. There is concern that it is difficult to maintain the exchange even after time.

  As described above, in an electronic component including a terminal having at least one of a lead-free plating layer and a lead-free solder on a surface of a base material, at least an exposed surface of the lead-free plating layer and the lead-free solder is formed on the first material. And a second material dispersed in the first material, wherein the second material initiates curing upon contact with a third substance that is different from either the first material or the second material. Covering with a coating layer, which is a material (in this embodiment, a humidity curable resin), is generated from the lead-free plating layer and the lead-free solder without sacrificing moisture resistance due to cracking of the coating layer. It was confirmed that whisker growth can be effectively suppressed.

  In addition, in the material structure employ | adopted in a present Example, the suitable compounding rate of the 2nd material in the said coating layer is with respect to the sum of the 1st material and 2nd material which comprise a coating layer from the said evaluation result. Although it was judged that it was 20 mass% or more and 70 mass% or less, the range of the said suitable mixture rate is not universal. That is, the suitable blending ratio of the second material in the coating layer varies depending on various conditions such as the type of material employed as the first material and the second material constituting the coating layer and the usage environment of the electronic component. However, the suitable blending ratio of the second material in the coating layer is, for example, the kind of material employed as the first material and the second material constituting the coating layer, the usage environment of the electronic component, and the like when the present invention is applied. It can be appropriately determined according to various conditions.

  Although several embodiments having specific configurations have been described above for the purpose of illustrating the present invention, the scope of the present invention is not limited to these exemplary embodiments, and patents Needless to say, modifications can be made as appropriate within the scope of the claims and the description of the specification.

  DESCRIPTION OF SYMBOLS 10 ... Coating layer, 11 ... 1st material, 12 ... 2nd material, 13 ... Network, 14 ... Moisture, 21 ... Whisker, 31 ... Liquid containing 1st material, 32 ... Liquid containing 2nd material, 33 ... Spray (Sprayer), 34 ... mist-like coating material, 40 ... electronic component, 41 ... circuit element, 42 ... terminal, 43 ... lead-free plating layer or lead-free solder, 44 ... substrate, 51 ... first material and second Liquid containing material, as well as 52 ... application liquid bath.

Claims (6)

An electronic component comprising a terminal having at least one of a lead-free plating layer and a lead-free solder on the surface of a base material,
At least an exposed surface of the lead-free plating layer and the lead-free solder is covered with a coating layer;
The coating layer comprises a first material and a second material dispersed in the first material;
The first material is an acrylic resin that is a moisture-proof material,
The second material is either a cyanoacrylate-based resin that is a moisture-curable resin that begins to cure by contact with moisture, or a vinyl acetate-based resin that is an anaerobic sealant that initiates curing by contact with a metal Or both
Electronic components. The electronic component according to claim 1,
The hardness of the second material after curing is greater than the hardness of the first material after curing;
Electronic components. A method of manufacturing an electronic component comprising a terminal having at least one of a lead-free plating layer and a lead-free solder on the surface of a base material,
Covering at least an exposed surface of the lead-free plating layer and the lead-free solder with a coating layer;
Including
The coating layer comprises a first material and a second material dispersed in the first material;
The first material is an acrylic resin that is a moisture-proof material,
The second material is either a cyanoacrylate-based resin that is a moisture-curable resin that begins to cure by contact with moisture, or a vinyl acetate-based resin that is an anaerobic sealant that initiates curing by contact with a metal Or both
Manufacturing method of electronic components. It is a manufacturing method of the electronic component according to claim 3 ,
The hardness of the second material after curing is greater than the hardness of the first material after curing;
Manufacturing method of electronic components. A method of manufacturing an electronic component according to claim 3 or 4 ,
Covering at least the exposed surface of the lead-free plating layer and the lead-free solder with the coating layer by a spray coating method,
Manufacturing method of electronic components. A method of manufacturing an electronic component according to claim 3 or 4 ,
By the dip coating method, at least the exposed surface of the lead-free plating layer and the lead-free solder is covered with the coating layer,
Manufacturing method of electronic components.

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