WO2017221419A1

WO2017221419A1 - Circuit board, method for manufacturing same, and electronic device

Info

Publication number: WO2017221419A1
Application number: PCT/JP2016/068898
Authority: WO
Inventors: 桂司佐藤; 岡本　正英; 薫子加藤; 健三井津; 弘幸鈴木; 淳角田; 孝晃北原
Original assignee: 株式会社日立製作所
Priority date: 2016-06-24
Filing date: 2016-06-24
Publication date: 2017-12-28

Abstract

A printed board 1 has: a through hole electrode 5 configured from a first electrode 5a, a second electrode 5b, and a third electrode 5c; an inserting component 2, which has a lead 2a that is disposed in a through hole 5d of the through hole electrode 5, and which is mounted on the front surface 1a side; and a solder connecting section 6, which connects the third electrode 5c and the lead 2a to each other, and which is provided from the front surface 1a side toward the rear surface 1b side. Furthermore, the third electrode 5c is provided with a first portion 5ca, on which the solder connecting section 6 is not disposed, and a second portion 5cb, on which the solder connecting section 6 is disposed, at least the first portion 5ca is covered with a first conductor film 8a, and a clearance 7 surrounded by the first conductor film 8a and the solder connecting section 6 is formed.

Description

Circuit board, manufacturing method thereof, and electronic apparatus

The present invention relates to a circuit board on which a terminal insertion type component is mounted, a method for manufacturing the circuit board, and an electronic device.

Many electronic control devices are equipped with various electronic components, and these electronic components are mounted on a circuit board such as a printed circuit board. For electronic components mounted on a circuit board, surface mount components mounted on the surface of the circuit board or insertion by inserting electronic component leads (terminal parts) into through holes provided in the circuit board There is a mounting component (hereinafter also simply referred to as an insertion component).

For joining electronic components and circuit boards, Sn-37Pb (unit: mass%), which can be soldered at around 220 ° C, and lead-free solder alloy Sn-3Ag-0.5Cu (unit: mass) that does not use lead %) Is used.

The reflow method and the flow method are mainly mentioned as the method for joining the electronic component to the circuit board. The reflow method is a solder bonding method that is mainly used for bonding surface-mounted components. For solder paste printing in which openings are formed in any shape on the electrodes formed on the substrate for bonding surface-mounted components. This is a process in which a solder paste is printed using a mask, and after mounting electronic components, the solder is melted and solidified in a reflow furnace to be joined. On the other hand, the flow method used for joining the insertion component inserts the lead of the insertion component into a through hole (through hole) having a land formed for inserting the lead of the insertion component on the circuit board. This is a process in which molten solder is supplied from the lower surface of the substrate to fill the through holes with solder and to join the lands and the leads of the mounting component.

In addition to these processes, there is an insert component reflow process in which insert components are soldered together with surface mount components. In surface mounting, an electrode is formed on a substrate facing a component to be surface mounted, a solder paste is printed on the electrode on the substrate using a printing mask having an arbitrary opening shape on the electrode, and then the surface mounting component is mounted. Install and melt and solidify the solder paste in a reflow oven. On the other hand, in the insert reflow process, an opening is also formed for the insert part copper electrode in the print mask, the solder paste is applied onto the copper electrode of the insert part during solder paste printing, and the insert part is inserted into the through hole. This is a process of heating and joining using a reflow furnace.

For example, in Japanese Patent Application Laid-Open No. 2012-243796 (Patent Document 1), the center of the lead of the insertion part is decentered with respect to the center of the insertion hole of the printed wiring board. A structure is disclosed in which a solder connection portion having a sufficient connection area is formed in a portion where the gap between the first and second portions is narrow.

Japanese Patent Application Laid-Open No. 2012-243796

課題 Describes issues when mounting insert parts using the insert reflow process. In order to ensure a sufficient amount of solder filling in the through hole (insertion hole) for mounting the insertion component, it is necessary to increase the opening area for the through hole of the metal mask in addition to the method described in Patent Document 1. However, when the lead interval of the inserted part is narrow, even if an attempt is made to increase the opening area for the through hole of the metal mask, the opening area necessary for one place cannot be ensured due to the relationship with the adjacent opening holes. Therefore, when the lead interval of the inserted component is narrow, the solder filling amount in the through hole is not sufficient, and connection failure may occur due to insufficient solder. Especially in a thick circuit board with a thickness of 1.6 mm or more, the copper electrode is exposed to the copper electrode on the back side opposite to the board surface on which the insertion part is inserted without being wetted with the copper electrode. The problem is that there are risks.

When the method shown in Patent Document 1 is adopted, solder connection strength can be obtained, but the amount of solder is reduced in a portion where the gap between the lead and the insertion hole of the printed wiring board is wide, and the copper electrode is covered. The solder does not spread so much and exposure of the copper electrode cannot be prevented.

An object of the present invention is to provide a technique capable of realizing a highly reliable solder connection in a technique for mounting an insertion component on a substrate.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

Of the inventions disclosed in this application, the outline of typical ones will be briefly described as follows.

The circuit board according to the present invention includes a first electrode having a first surface, a second electrode having a second surface located on the opposite side of the first surface, and the first electrode and the first electrode. A through electrode having a third electrode connected to the second electrode, and an insertion component in which a terminal portion is disposed in a hole portion of the through electrode and is mounted on the first surface side. Furthermore, the third electrode and the terminal portion are connected, and a solder connection portion is provided from the first electrode side toward the second electrode side. Further, the third electrode includes a first portion where the solder connection portion is not disposed and a second portion where the solder connection portion is disposed, and the third electrode is connected to the solder connection portion on the first portion. One conductor film is formed, and a gap is formed in a region surrounded by the first conductor film and the solder connection portion.

The circuit board manufacturing method according to the present invention includes (a) a first electrode having a first surface, a second electrode having a second surface located on the opposite side of the first surface, and Solder is applied to the end on the second surface side of the third electrode of the circuit board provided with a through electrode having a third electrode connected to the first electrode and the second electrode The process of carrying out. And (b) after the step (a), heating the solder to form a solder plating film on the end of the third electrode; (c) after the step (b), A step of embedding solder from the surface side of 1 into the hole of the through electrode. And (d) after the step (c), a step of inserting the terminal portion of the insertion part into the hole portion of the through electrode from the first surface side and covering the terminal portion with the solder, (e) After the step (d), the method includes a step of heating and curing the solder in the hole to form a solder connection portion connected to the terminal portion and the third electrode.

An electronic device according to the present invention includes a first electrode having a first surface, a second electrode having a second surface located on the opposite side of the first surface, the first electrode, and the first electrode. A through electrode including a third electrode connected to the second electrode; and an insertion component in which a terminal portion is disposed in the hole of the through electrode and is mounted on the first surface side. Furthermore, the circuit board includes a solder connection portion that connects the third electrode and the terminal portion and is provided from the first electrode side toward the second electrode side. Further, the third electrode includes a first portion where the solder connection portion is not disposed and a second portion where the solder connection portion is disposed, and the third electrode is connected to the solder connection portion on the first portion. One conductor film is formed, and a gap is formed in a region surrounded by the first conductor film and the solder connection portion.

Among the inventions disclosed in the present application, the effects obtained by typical ones will be briefly described as follows.

In a circuit board on which an insertion component is mounted, a manufacturing method thereof, and an electronic device, highly reliable solder connection can be realized, and the reliability of the circuit board and the electronic device can be improved.

It is a perspective view which shows an example of the structure of the circuit board of Embodiment 1 of this invention. It is a partial expanded sectional view which shows an example of the solder connection structure of the insertion component shown in FIG. It is a partial expanded sectional view which shows the solder connection structure of the insertion component of a comparative example. It is a partial expanded sectional view which shows an example of the mounting method of the insertion component in the circuit board of Embodiment 1 of this invention. It is a partial expanded sectional view which shows an example of the mounting method of the insertion component in the circuit board of Embodiment 1 of this invention. It is a partial expanded sectional view which shows an example of the mounting method of the insertion component in the circuit board of Embodiment 1 of this invention. It is a partial expanded sectional view which shows an example of the mounting method of the insertion component in the circuit board of Embodiment 1 of this invention. It is a partial expanded sectional view which shows an example of the mounting method of the insertion component in the circuit board of Embodiment 1 of this invention. It is a schematic diagram which shows an example of the solder supply conditions in the mounting method of the insertion component of the circuit board of Embodiment 1 of this invention. It is a front view which shows an example of the structure of the electronic device (server) of Embodiment 1 of this invention. It is a partial expanded sectional view which shows an example of the solder connection structure of the insertion component in the circuit board of Embodiment 2 of this invention.

In the following embodiments, the description of the same or similar parts will not be repeated in principle unless particularly necessary.

Further, in the following embodiment, when it is necessary for the sake of convenience, the description will be divided into a plurality of sections or embodiments, but they are not irrelevant to each other unless otherwise specified. The other part or all of the modifications, details, supplementary explanations, and the like are related.

Also, in the following embodiments, when referring to the number of elements (including the number, numerical value, quantity, range, etc.), particularly when clearly indicated and when clearly limited to a specific number in principle, etc. Except, it is not limited to the specific number, and it may be more or less than the specific number.

Further, in the following embodiments, the constituent elements (including element steps) are not necessarily indispensable unless otherwise specified and clearly considered essential in principle. Needless to say.

Further, in the following embodiments, regarding constituent elements and the like, when “consisting of A”, “consisting of A”, “having A”, and “including A” are specifically indicated that only those elements are included. It goes without saying that other elements are not excluded except in the case of such cases. Similarly, in the following embodiments, when referring to the shapes, positional relationships, etc. of the components, etc., the shapes are substantially the same unless otherwise specified, or otherwise apparent in principle. And the like are included. The same applies to the above numerical values and ranges.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments, and the repetitive description thereof will be omitted. Further, even a plan view may be hatched for easy understanding of the drawing.

(Embodiment 1)
FIG. 1 is a perspective view showing an example of the structure of a circuit board according to Embodiment 1 of the present invention, and FIG. 2 is a partially enlarged sectional view showing an example of a solder connection structure of an insertion part shown in FIG.

The circuit board according to the first embodiment shown in FIG. 1 is an electronic circuit board on which a plurality of electronic components can be mounted. There are various types of circuit boards such as a printed board, a ceramic board, a flexible board, and a metal core board. In the first embodiment, the printed board 1 will be described as the circuit board.

As shown in FIG. 1, the printed circuit board 1 has a plurality of electronic components mounted on the surface 1a thereof. The electronic components include an insertion component 2 that is an insertion mounting component and a surface mounting component.

As shown in FIG. 2, the insertion component 2 has a lead (terminal portion) 2a inserted into a through hole 5d of a through hole electrode 5 which is a through electrode provided on the printed circuit board 1, and the lead 2a and the through hole 5d. And are parts to be soldered.

On the other hand, the surface-mounted component is an IC (Integrated Circuit) 3 or a chip component 4 or the like, and is a component that is solder-connected to an electrode provided on the surface 1a of the printed board 1.

As shown in FIG. 2, the printed circuit board 1 according to the first embodiment has a front surface 1a and a back surface 1b located on the opposite side of the front surface 1a, and at least one insertion component 2 is solder-mounted. It is a substrate. That is, the insertion part 2 has at least one through-hole electrode 5 to which solder connection is made.

Next, the solder connection structure of the insertion component 2 in the printed circuit board 1 according to the first embodiment will be described with reference to FIG. First, the detailed structure of the through-hole electrode 5 that is a through electrode formed on the printed circuit board 1 will be described.

The through-hole electrode 5 is formed on the front surface 1a of the printed circuit board 1 and has a first surface 5aa, and is formed on the back surface 1b of the printed circuit board 1 and opposite to the first surface 5aa. A second electrode 5b having a second surface 5ba located at the first electrode 5a, and a third electrode 5c connected to the first electrode 5a and the second electrode 5b.

Here, each of the first electrode 5a and the second electrode 5b is annular, the third electrode 5c is cylindrical, and the first electrode 5a, the second electrode 5b, and the third electrode 5c. And are configured as an electrode. A through hole (through hole) 5d, which is a hole, is formed in the central portion of the through hole electrode 5. As a result, the through hole 5d opens on the front surface 1a and the back surface 1b of the printed circuit board 1. Yes.

The through-hole electrode 5 is made of, for example, a material whose main alloy is copper. In this case, the first electrode 5a, the second electrode 5b, and the third electrode 5c are formed of the same material having copper as a main alloy.

In addition, an insulating film made of a resist 9 is formed around each of the annular first electrode 5 a and the annular second electrode 5 b, and adjacent through-hole electrodes 5 are insulated from each other by the resist 9. .

The insertion component 2 is mounted on the first surface 5aa side with the lead 2a disposed in the through-hole 5d of the through-hole electrode 5, and the lead 2a of the insertion component 2 and the through-hole electrode are mounted in the through-hole 5d. The third electrode 5c is electrically connected by the solder connection portion 6. That is, the lead 2a of the insertion component 2 and the through-hole electrode 5 are electrically connected by the solder connection portion 6 made of solder. In addition, the solder connection part 6 is provided toward the 2nd electrode 5b side from the 1st electrode 5a side.

That is, the third electrode 5c includes a first portion 5ca that is not directly connected to the solder connection portion 6 without the solder connection portion 6 disposed therein, and a second portion that is directly connected to the solder connection portion 6 with the solder connection portion 6 disposed therein. Part 5cb.

And the 1st conductor film 8a connected with the solder connection part 6 is formed in the 1st part 5ca of the 3rd electrode 5c. Further, a gap 7 is formed in a region surrounded by the first conductor film 8 a and the solder connection portion 6. In other words, in the printed circuit board 1 of the first embodiment, the first conductor film 8a is formed on the first portion (end portion) 5ca on the second surface 5ba side facing the gap 7 in the third electrode 5c. The first portion 5ca is covered with the first conductor film 8a. The first conductor film 8a is preferably made of a material having higher wettability with respect to the solder than the material forming the third electrode 5c.

That is, when the through-hole electrode 5 is formed of a material having copper as a main alloy, the first conductor film 8a may be made of a material having higher wettability with respect to solder than a material having copper as a main alloy. preferable.

Here, the first portion 5ca, which is the end of the third electrode 5c of the through-hole electrode 5 on the second surface 5ba side, is directed toward the second surface 5ba of the third electrode 5c toward the solder connection portion 6. It is the part which protruded from. The second portion 5cb, which is the portion on the first surface 5aa side of the first portion 5ca of the third electrode 5c, is directly connected to the solder connection portion 6.

Further, a second conductor film 8b is formed on the second surface 5ba of the second electrode 5b on the back surface 1b side of the printed circuit board 1, and the first electrode 5a on the front surface 1a side is formed on the second surface 5ba. A third conductor film 8c is formed on the surface 5aa.

The first conductor film 8a, the second conductor film 8b, and the third conductor film 8c are, for example, solder plating films, and are more preferably solder plating films made of the same material as the solder of the solder connection portion 6. preferable.

The feature of the printed circuit board 1 according to the first embodiment is that at least the first portion 5 ca protruding from the solder connection portion 6 of the third electrode 5 c of the through-hole electrode 5 toward the second surface 5 ba is the first conductor. It is covered with the film 8a. Further, preferably, as described above, the second surface 5ba of the second electrode 5b and the first surface 5aa of the first electrode 5a are also conductor films (second conductor film 8b and third conductor film 8c), respectively. Is covered by.

Each of the first conductor film 8a, the second conductor film 8b, and the third conductor film 8c is not limited to being made of solder that forms the solder connection portion 6, but is a material that forms the through-hole electrode 5 (for example, As long as the film is made of a material having higher wettability to solder than copper, a nickel plating film or the like may be used.

As described above, in the printed circuit board 1 according to the first embodiment, the first portion 5ca on the second surface 5ba side protruding from the solder connection portion 6 of the third electrode 5c of the through-hole electrode 5 is the first portion 5ca. Since it is covered with the conductor film 8a, the first portion 5ca of the through-hole electrode 5 can be prevented from being corroded.

Here, the details of the problem to be solved by the present invention will be described. FIG. 3 is a partially enlarged cross-sectional view showing a solder connection structure of an insertion part of a comparative example, which the present inventor has compared and examined.

For example, when the solder paste 11 shown in FIG. 6 is arranged in the through-hole electrode 5 using the metal mask 10 shown in FIG. When the area of the opening 10a cannot be obtained sufficiently, or when the thickness of the printed circuit board 51 is, for example, 1.6 mm or more, the amount of solder paste to be supplied is insufficient. When the amount of solder paste is insufficient, as shown in the comparative example of FIG. 3, in the printed circuit board 51, the copper electrode (through-hole electrode) on the back surface 51b side opposite to the substrate surface (front surface 51a) on which the insertion component 2 is inserted. Part of the copper electrode (the first portion 5ca of the through-hole electrode 5) is exposed without the solder getting wet up to the first portion 5ca of the third electrode 5c. When a part of the copper electrode (the first portion 5ca of the through-hole electrode 5) is exposed, a problem that the copper electrode corrodes occurs. Further, when the electronic control device (electronic device) is operated, there is a risk of failure due to poor electrical connection due to corrosion of the copper electrode (the first portion 5ca of the through-hole electrode 5). Challenges are also raised.

Regarding the thickness of the printed circuit board 51, when the thickness is generally 1.6 mm or more, the amount of solder paste tends to be insufficient. In this case, the copper electrode (the first portion 5ca of the through-hole electrode 5) Exposure is also likely to occur.

Therefore, in the printed circuit board 1 according to the first embodiment, as shown in FIG. 2, the first portion 5ca protruding from the solder connection portion 6 in the third electrode 5c of the through-hole electrode 5 is the first conductor film 8a. As a result, the corrosion of the through-hole electrode 5 due to the exposure of the first portion 5ca of the through-hole electrode 5 can be prevented.

Next, a method for manufacturing the printed circuit board 1 according to the first embodiment will be described. 4 to 8 are partial enlarged cross-sectional views showing an example of a method for mounting the insertion component on the circuit board according to the first embodiment of the present invention, and FIG. 9 shows the insertion component for the circuit board according to the first embodiment of the present invention. It is a schematic diagram which shows an example of the solder supply conditions in the mounting method.

First, the entire reflow process of the insertion part 2 will be described. The metal mask 10 having an opening 10a for printing the solder paste 11 on the through-hole electrode 5 and the through-hole 5d is inserted on the printed board 1. It is installed on the surface 1a side where the component 2 is inserted. Thereafter, the solder paste 11 is printed to apply on the through-hole electrode 5, and the through-hole 5d is filled with the solder paste 11. Thereafter, the lead 2a of the insertion component 2 is inserted into the through hole 5d and heated in a reflow furnace, whereby the solder paste 11 is melted and the solder connection portion 6 is formed.

Specifically, as shown in FIG. 4, in the mounting step of the surface component on the back surface side of the printed circuit board 1, which is a pre-process of the reflow process of the inserted component 2, the through hole 5 d for mounting the inserted component 2 and the printed circuit board 1. The solder paste 11 is supplied to the copper electrode (second electrode 5b) on the back surface side by a printing method or an inkjet method. And it is a solder plating film on the inner surface of the copper electrode (second electrode 5b) on the back side and the desired through hole 5d (the first portion 5ca of the third electrode 5c) in the reflow process in the mounting of the insertion component 2 A first conductor film 8a is formed.

This process is preferably performed in the same process as the reflow process for other surface-mounted components mounted on the back surface 1b of the printed circuit board 1, but may be performed by providing another process. In addition, the thickness of the printed circuit board 1 is 1.6 mm or more, for example.

More specifically, first, the first electrode 5a having the first surface 5aa, the second electrode 5b having the second surface 5ba located on the opposite side of the first surface 5aa, and the first electrode 5a. The first portion (end portion) 5ca on the second surface 5ba side of the third electrode 5c of the printed board 1 provided with the through-hole electrode 5 having the third electrode 5c connected to the second electrode 5b. Then, solder is applied on the second surface 5ba of the second electrode 5b. Here, for example, solder (solder paste) is applied manually using a soldering iron or the like.

After the solder is applied, the solder is heated by reflow or the like to form a solder plating film on the first part (end part) 5ca of the third electrode 5c and the second surface 5ba of the second electrode 5b. A first conductor film 8a and a second conductor film 8b are formed.

After forming the first conductor film 8a and the second conductor film 8b, as shown in FIG. 6, the copper electrode (first electrode 5a) on the surface 1a side of the printed circuit board 1 and its peripheral portion, and further, the through hole 5d Solder paste 11 is supplied inside. At that time, first, as shown in FIG. 5, a metal mask 10 is arranged on the surface 1 a of the printed circuit board 1. At this time, the metal mask 10 is arranged with the position of the opening 10 a of the metal mask 10 aligned with the through-hole electrode 5.

After the metal mask 10 is disposed, a solder paste (solder) 11 is embedded from the first surface 5aa side of the printed board 1 into the through hole 5d of the through hole electrode 5 as shown in FIG. That is, the solder paste 11 is supplied and filled (filled) into the copper electrode (first electrode 5a) on the surface 1a side of the printed circuit board 1 and its peripheral portion, and further inside the through hole 5d.

Here, the solder supply amount when the solder paste 11 is filled in the through hole 5d will be described. The solder supply amount that is the supply amount of the solder paste 11 can be expressed by the following equation.

Solder supply amount> area of through hole 5d × thickness of printed circuit board 1 × solder filling rate (%) (1).

Here, as shown in the schematic diagram of FIG. 9, when the thickness of the printed circuit board 1 is T, the diameter of the through hole 5d is L, and the solder filling rate is V, the area of the through hole 5d is 1/4. (ΠL ² ), whereby the solder supply amount becomes solder supply amount> ¼ · (πL ² ) · T · V.

Therefore, by supplying the solder paste 11 based on the solder supply amount of the formula (1), the solder paste 11 and the first conductor film 8a are formed in the through hole 5d of the through hole electrode 5 as shown in FIG. Can be connected.

After supplying the solder paste, as shown in FIG. 7, the lead (terminal portion) 2a of the insertion component 2 is inserted into the through hole 5d from the surface 1a side of the printed circuit board 1.
That is, the lead 2 a of the insertion component 2 is inserted into the through hole 5 d of the through hole electrode 5 from the first surface 5 aa side of the printed circuit board 1 so that the lead 2 a is covered with the solder paste 11.

Next, the solder paste 11 in the through hole 5d is heated and then cured, and as shown in FIG. 8, solder is used so that the lead 2a and the second portion 5cb of the third electrode 5c are solder-connected. A connecting portion 6 is formed. That is, the solder paste 11 applied from the surface 1a side of the printed circuit board 1 is melted by a reflow process, and the lead 2a of the insertion component 2 and the copper electrode (through hole electrode 5) of the printed circuit board 1 are connected to the solder connection portion. 6 for solder connection.

At this time, the solder connection portion 6 and the first conductor film 8a, which is a solder plating film formed on the first portion 5ca of the third electrode 5c, and the solder connection portion 6 and the second electrode 5b The formed second conductor film 8b is integrally connected after curing by reflow heating / melting.

Furthermore, the solder connection portion 6 and the third conductor film 8c formed on the first electrode 5a are similarly connected together after curing by reflow heating / melting.

Therefore, as shown in FIG. 8, the insertion component 2 is solder-mounted on the printed circuit board 1, and the through-hole electrode 5 can be covered with the solder connection portion 6 and the solder plating film as the conductor film.

The area of the opening 10a of the metal mask 10 cannot be increased due to the insertion component 2 having the narrow pitch leads 2a by the method of manufacturing the printed circuit board 1 of the first embodiment, or a thick substrate (for example, having a thickness of 1 The through-hole electrode 5 is not exposed even in the printed circuit board 1 where the solder does not wet up to the copper electrode on the back surface 1b side (the first portion 5ca of the third electrode 5c). Thereby, a highly reliable solder connection structure can be obtained.

Also, in the double-sided mounting board, since solder plating can be performed when mounting the component on the back surface 1b side, no additional process is required, and man-hours are not increased.

Next, the electronic device according to the first embodiment will be described. FIG. 10 is a front view showing an example of the structure of the electronic device (server) according to the first embodiment of the present invention.

In the first embodiment, a server 20 capable of accommodating a plurality of printed circuit boards 1 shown in FIG. 1 will be described as an example of an electronic device.

The server 20 shown in FIG. 10 is provided with a rack 21 that is also a substrate housing unit. A blade-type information processing device 22 is inserted into the rack 21.

The blade-type information processing device 22 has a communication unit that communicates with other devices on the back side, and a display unit 23 that indicates communication and an operating state is provided on the front side. The display unit 23 is not an essential component, but when it is provided, the operation state can be confirmed.

The blade-type information processing apparatus 22 has a function as a server alone, but may be operated in combination with a plurality of blades.

The blade type information processing apparatus 22 incorporates the printed circuit board 1 shown in FIG. 1 of the first embodiment. That is, at least one insertion component 2 is solder-mounted on the printed circuit board 1 built in the information processing apparatus 22, and the insertion component 2 has a solder connection structure as shown in FIG. The connection portion 6 and the solder plating film (first conductor film 8a, second conductor film 8b, and third conductor film 8c) are covered.

This can contribute to extending the life of the information processing apparatus 22. In addition, the reliability of the information processing apparatus 22 can be improved. As a result, the service life of the server 20 can be extended. Furthermore, the reliability of the server 20 can be improved.

The printed circuit board 1 according to the first embodiment can be applied to a storage having a storage device such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive), a general-purpose electronic computer, or the like.

Also, the present invention can be applied to diagnostic devices using ultrasonic waves, light or X-rays, and power devices such as inverters, IGBTs (Insulated Gate Bipolar Transistors), AC generators, alternators, or power modules.

These devices can improve the life of the entire device by improving the life of the printed circuit board 1 using the printed circuit board 1 of the first embodiment.

In addition, the apparatus having the above-described printed circuit board 1 is generically called an electronic apparatus.

According to the printed circuit board 1 and the server 20 of the first embodiment, the first portion 5ca on the second surface 5ba side protruding from the solder connection portion 6 in the third electrode 5c of the through-hole electrode 5 in the printed circuit board 1 is provided. Since it is covered with the first conductor film 8a such as a solder plating film, the first portion 5ca of the through-hole electrode 5 can be prevented from being corroded.

That is, since the first portion 5ca of the through-hole electrode 5 is not exposed, a highly reliable solder connection is realized, and as a result, the reliability of the printed circuit board (circuit board) 1 and the server (electronic device) 20 can be improved. it can.

In the through-hole electrode 5, it is more preferable that not only the first portion 5ca but also the second electrode 5b on the back surface 1b side is covered with a conductor film, and further, the first electrode 5a on the front surface 1a side. Is most preferably covered with a conductive film. In this case, corrosion of the entire through-hole electrode 5 can be prevented.

Also in the reflow process in which the insertion component 2 is mounted using the solder paste 11, a highly reliable solder connection structure in which the through-hole electrode 5 is not exposed due to a limited amount of solder paste can be obtained.

(Embodiment 2)
FIG. 11 is a partial enlarged cross-sectional view showing an example of a solder connection structure of an insertion part in the circuit board according to the second embodiment of the present invention. In the structure shown in FIG. 11, the length of the lead (terminal part) 2 a of the insertion part 2 is larger than the thickness of the printed board 31 in the solder connection part 6 between the insertion part 2 shown in FIG. 1 and the printed board 31 shown in FIG. 11. The lead 2 a is short and does not protrude from the back surface 31 b side of the printed circuit board 31.

Specifically, not only the relationship between the length of the lead 2a and the thickness of the printed circuit board 31, but the lead 2a of the inserted component 2 is opposite to the surface 31a of the printed circuit board 31 when the inserted component 2 is solder-mounted on the printed circuit board 31. The structure is recessed from the rear surface 31b.

That is, the lead 2a is retracted without protruding from the back surface 31b of the printed circuit board 31 in a state where the insertion component 2 is solder-mounted, and the first portion 5ca of the third electrode 5c of the through-hole electrode 5 is the first portion 5ca. 1 conductor film 8a is covered, 2nd surface 5ba of 2nd electrode 5b is covered with 2nd conductor film 8b, and 1st surface 5aa of 1st electrode 5a is further covered with 3rd conductor film 8c. Covered. Each of the first conductor film 8a, the second conductor film 8b, and the third conductor film 8c is, for example, a solder plating film, but may be a nickel plating film or the like.

In the reflow process of the insertion part 2 of the comparative example described with reference to FIG. 3, since the solder wets and spreads to the electrode part on the back surface side, the lead 2 a protrudes from the back surface side of the printed circuit board 51 to form a solder fillet. It was necessary to become. On the other hand, even if the lead 2a of the insertion component 2 is shorter than the thickness of the printed circuit board 1 by using the method for manufacturing the printed circuit board 1 of the first embodiment shown in FIG. An effect equivalent to that of the printed circuit board 1 can be obtained.

In other words, if the lead 2a is short, the inner wall of the through-hole electrode 5 (for example, the first portion (end portion) 5ca of the third electrode 5c) is more easily exposed, but the printed circuit board 31 of the second embodiment. By adopting this solder mounting structure, an effect equivalent to that of the printed circuit board 1 shown in FIG. 1 can be obtained, and as a result, corrosion of the through-hole electrode 5 can be prevented.

And, similarly to the first embodiment, a highly reliable solder connection is realized, whereby the reliability of the printed board (circuit board) 31 and the electronic device including the printed board 31 can be improved.

Note that the present invention is not limited to the above-described embodiment, and includes various modifications. For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to one having all the configurations described.

Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. . Moreover, it is also possible to add, delete, and replace other configurations for a part of the configuration of each embodiment. In addition, each member and relative size which were described in drawing are simplified and idealized in order to demonstrate this invention clearly, and it becomes a more complicated shape on mounting.

In the first embodiment, it is more preferable that the first portion 5ca, the second electrode 5b, and the first electrode 5a are covered with the conductor film in the through-hole electrode 5. For example, when the first portion 5ca and the second electrode 5b are covered with the conductive film, erosion from the back surface 1b side toward the inside can be prevented.

Even when the first electrode 5a on the surface 1a side is not covered with the conductor film, the insertion part 2 is mounted on the surface 1a side of the printed circuit board 1, so that the first electrode on the surface 1a side. Erosion toward the inside from the electrode 5a can be suppressed.

1 Printed circuit board (circuit board)
2 Insertion part 2a Lead (terminal part)
5 Through-hole electrode (through electrode)
5a 1st electrode 5aa 1st surface 5b 2nd electrode 5ba 2nd surface 5c 3rd electrode 5ca 1st part (end part)
5d Through hole (hole)
6 Solder connection 7 Air gap 8a First conductor film 8b Second conductor film 8c Third conductor film 20 Server (electronic device)

Claims

A first electrode having a first surface, a second electrode having a second surface located on the opposite side of the first surface, and a first electrode connected to the first electrode and the second electrode A through electrode comprising three electrodes;
A terminal part is disposed in the hole part of the through electrode, and an insertion component mounted on the first surface side;
Connecting the third electrode and the terminal portion, a solder connection portion provided from the first electrode side toward the second electrode side;
Have
The third electrode includes a first portion where the solder connection portion is not disposed and a second portion where the solder connection portion is disposed,
A first conductor film connected to the solder connection portion is formed on the first portion,
A circuit board, wherein a gap is formed in a region surrounded by the first conductor film and the solder connection portion.
The circuit board according to claim 1,
A circuit board, wherein a second conductor film is formed on the second surface of the second electrode.
The circuit board according to claim 1,
A circuit board, wherein a third conductor film is formed on the first surface of the first electrode.
The circuit board according to claim 3,
The circuit board, wherein the first conductor film, the second conductor film, and the third conductor film are solder plating films.
The circuit board according to claim 1,
The circuit board, wherein the first conductor film is a nickel plating film.
The circuit board according to claim 1,
The circuit board, wherein the terminal part of the insertion part is recessed from the back surface of the circuit board.
The circuit board according to claim 1,
The circuit board has a thickness of 1.6 mm or more.
(A) a first electrode having a first surface, a second electrode having a second surface opposite to the first surface, and the first electrode and the second electrode; Applying solder to the end of the third electrode on the second surface side of the circuit board provided with a through electrode having a third electrode to be connected;
(B) after the step (a), heating the solder to form a solder plating film on the end of the third electrode;
(C) After the step (b), a step of burying solder in the hole of the through electrode from the first surface side;
(D) After the step (c), a step of inserting a terminal portion of an insertion part into the hole portion of the through electrode from the first surface side and covering the terminal portion with the solder,
(E) After the step (d), the step of heating and curing the solder in the hole to form a solder connection portion connected to the terminal portion and the third electrode;
A method for manufacturing a circuit board, comprising:
In the manufacturing method of the circuit board according to claim 8,
In the step (a), the solder is applied to the end portion of the third electrode and the second surface of the second electrode,
In the step (b), the solder plating film is formed on the end portion of the third electrode and the second surface of the second electrode.
In the manufacturing method of the circuit board according to claim 8,
The circuit board manufacturing method in which the supply amount of the solder embedded in the hole of the through electrode in the step (c) is a relationship of solder supply> area of the hole × thickness of the circuit board × solder filling rate. Method.
A first electrode having a first surface, a second electrode having a second surface located on the opposite side of the first surface, and a third electrode connected to the first electrode and the second electrode A through-hole electrode including the electrode, a terminal portion disposed in a hole portion of the through-electrode, and an insertion component mounted on the first surface side, and the third electrode and the terminal portion connected to each other. And a solder connection portion provided from the first electrode side toward the second electrode side, and a circuit board comprising:
The third electrode includes a first portion where the solder connection portion is not disposed and a second portion where the solder connection portion is disposed,
A first conductor film connected to the solder connection portion is formed on the first portion,
An electronic device, wherein a gap is formed in a region surrounded by the first conductor film and the solder connection portion.
The electronic device according to claim 11.
An electronic device, wherein a second conductor film is formed on the second surface of the second electrode.
The electronic device according to claim 11.
An electronic device, wherein a third conductor film is formed on the first surface of the first electrode.
The electronic device according to claim 13.
The electronic device, wherein the first conductor film, the second conductor film, and the third conductor film are solder plating films.
The electronic device according to claim 11.
The electronic device, wherein the terminal part of the insertion part is retracted from the surface of the circuit board.