JP2007299816A - Electronic component mounting board and method of manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic component mounting board wherein soldering failure is prevented, as well as a method of manufacturing the same. <P>SOLUTION: The electronic component mounting board 1 is provided with a base substrate 15 made of an insulator, a first pattern 3 which is formed on one surface of the base substrate 15 and is formed of a conductive layer, a land 5 which is provided in the first pattern 3 and is coated with a solder, and a second pattern 5 which is formed on the other surface of the base substrate 15 and is formed of a conductive layer. A through-hole 6 penetrates the first and second patterns 3 and 5 therein. A plurality of through-holes 6 are made outside the land 5. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electronic component mounting board to which a reflow soldering method is applied and a method for manufacturing the electronic component mounting board.

In the reflow soldering method, the solder paste of each electronic component is heated by carrying the substrate after the cream solder pattern printing process and the mounting process of the electronic component into a heating furnace and heating the substrate while being conveyed by a conveyor or the like. I am trying to do it. (For example, see Patent Document 1)
JP 2004-253530 A

  In recent years, in view of environmental problems, the frequency of using lead-free solder (lead-free solder) is increasing. However, this lead-free solder has a higher melting temperature than conventional eutectic solder, and the difference between the melting temperature and the damage temperature of electronic components is small.

  For this reason, when lead-free solder is used, if the surface temperature of the substrate is raised due to melting of the solder, the electronic component may be damaged. On the other hand, if the heating strength and the heating time are suppressed in order to prevent damage to the electronic component, the solder is not sufficiently melted, and soldering failure (soldering cannot be surely performed) may occur.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a circuit board capable of preventing poor soldering.

  In order to solve the above-mentioned problem, the technical means taken in the present invention is, as described in claim 1, provided by a base substrate made of an insulator and a conductive substrate provided on one surface of the base substrate. A first pattern, a land provided on the first pattern and coated with solder, a second pattern formed on the other surface of the base substrate and made of a conductive layer, the first pattern, and the second pattern An electronic component mounting board having a pattern penetrated through a through hole, wherein a plurality of the through holes are provided outside the land. In this case, the land has a circular or rectangular shape so that the electronic component to be mounted can be reliably installed at a desired position. In this case, in the vicinity of the land (about 1 to 3 mm from the end of the land, more preferably 2 mm), the heat transfer characteristics of the base substrate are taken into consideration at regular intervals within the region of the first pattern. It is preferable that a plurality are provided.

 The through hole is preferably formed around the land.

 Further, in order to solve the above-mentioned problems, the technical means taken in the present invention includes a base substrate and a first layer comprising a conductive layer provided on one surface of the base substrate. An electronic component mounting board for mounting an electronic component by soldering on an insulating circuit board comprising a pattern, a second pattern made of a conductive layer provided on the other surface, and a land provided on the first pattern In the manufacturing method, using the circuit board penetrating the base substrate, the first pattern, and the second pattern through a through hole provided outside the land, an application step of applying solder to the land; An installation step of installing the electronic component on the land, and heating from both sides of the circuit board on which the electronic component is installed, so that heat applied to the other surface is passed through the through hole. And a heating step for transmitting to the land Te.

  In the heating step, heating from the other surface of the circuit board may be stronger than heating from one surface of the circuit board.

  According to the electronic component mounting substrate and the electronic component mounting substrate manufacturing method of the present invention, since the first pattern and the second pattern are penetrated through the through holes, when the substrate is heated at the time of melting the solder, Not only heat is supplied to the upper solder from the first pattern, but also heat is supplied from the second pattern to the solder on the land through the through holes. In addition, since a plurality of through holes are formed outside the land, sufficient heat is supplied to the solder. Therefore, according to the present invention, soldering can be performed reliably, and poor soldering can be prevented. With the above configuration, even if the heating of the circuit board is suppressed in consideration of the heat resistance of the electronic component, sufficient heat is supplied to the lands, and soldering is ensured.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic view of a component mounting board 1 according to the present invention, and FIG. 2 is a view in the direction of arrow II in FIG.

 The electronic component mounting board 1 includes a circuit board 2 and an electronic component 7 installed via solder 8. The circuit board 2 includes a base substrate 15, a pattern (first pattern) 3, a pattern (second pattern) 4, lands 5, and through holes 6. The base substrate 15 has a plate shape made of an insulator (bakelite, epoxy resin, etc.). The pattern 3 is provided on the surface 15a of the base substrate 15 and is made of a conductive layer such as silver foil or copper foil. The pattern 4 is provided on the back surface 15b of the base substrate 15 and is made of a conductive layer such as copper foil or silver foil. The pattern 4 is electrically independent (not connected to an electronic component or the like). Pattern 3 and pattern 4 are formed by known etching. The land 5 is formed at a desired position where the electronic component 7 of the pattern 3 is mounted, and the electronic component 7 (resistor, coil, relay, capacitor, IC, etc.) is soldered. The land 5 has a circular or rectangular shape in accordance with the lead or terminal shape of the electronic component, and is a part of the pattern 3 and is provided integrally with the pattern 3. The land 5 is coated with cream solder (lead-free solder) to form a solder layer 8. The electronic component 7 is installed on the solder 8 layer at the terminal portion 7a. The through hole 6 penetrates the pattern 3, the base substrate 15, and the pattern 4 in the thickness direction of the circuit board 2 (the vertical direction in FIG. 1). A plurality of through holes 6 are provided outside the land 5 (positions of about 1 to 3 mm from the end of the land 5, more preferably 2 mm). In this case, it is also possible to provide a plurality in the land 5 region. As shown in FIG. 1, a plurality of through holes 6 are provided around the land 5 (in the figure, only a part of the through holes 6 are numbered). A conductive layer such as copper plating or silver plating is applied to the inner surface of the through hole 6 in order to connect the pattern 3 and the pattern 4.

  Next, a method for manufacturing an electronic component mounting board will be described.

  The manufacturing method includes a step of preparing the circuit board 2 having the plurality of through holes 6 described above, a solder application step of applying solder to the circuit substrate, an installation step of installing electronic components, and a heating step of melting the solder. It has.

  FIG. 3 is a schematic view of a heating device 10 for heating the circuit board 2 in which the electronic component 7 is installed via the solder layer. The heating device 10 is incorporated in a part of the production line for the circuit board 2. The circuit board 2 is put into the heating device 10 after finishing the application of the cream solder and the mounting of the electronic component 7 (see FIG. 1). The heating device 10 is provided with a conveyor 11 and a heater 12. The conveyor 11 is for conveying the circuit board 2 in a predetermined direction (P direction in FIG. 3). The heater 12 is disposed above and below the conveyor 11. The heater 12 is disposed along the conveyance direction P of the circuit board 2 on which electronic components are installed. As the heater 12, for example, an infrared panel heater can be applied. The heater 12 heats the circuit board 2 provided with the electronic components 7 conveyed by the conveyor 11 with hot air. As a result, the solder layer 8 applied to a predetermined portion (land 5) of the circuit board 2 is melted, and the electronic component 7 is soldered to the circuit board 2. The heating process of the circuit board 2 may be such that heating from the lower surface side (heating amount, heating temperature, heating time) is stronger than heating from the upper surface side of the circuit board 2. With such a configuration, the solder can be reliably melted without strongly heating the electronic component.

  According to the electronic component mounting board 1 of the present invention, when the circuit board 2 is heated by the heater 12 of the heating device 10, not only heat is supplied from the pattern 3 to the land 5 but also from the pattern 4. Heat is supplied to the land 5 through 6. In this structure, even if the heating of the circuit board 2 (for example, the heating of the upper heater 12) is suppressed in consideration of the heat resistance of the electronic component 7, sufficient heat is supplied to the land 5. Thereby, since the solder 8 is sufficiently melted, the soldering of the electronic component 7 to the land 5 is surely performed, and defective soldering can be prevented.

  Furthermore, in the embodiment of the present invention, since no component is mounted on the pattern 4, most of the heat received by the pattern 4 from the heater 12 is transferred to the pattern 3 through the through hole 6, and the land 5 Heat can be supplied efficiently. Note that an electronic component may be mounted on the pattern 4.

  4 (a) and 4 (b) show another embodiment of the present invention. As shown in FIG. 4A, if a large area is secured in a portion of the pattern 3 around the land 5 and more through holes 6 are provided in the portion, more heat is supplied to the land 5. Obviously. Further, as shown in FIG. 4 (b), in order to supply heat to a part of the land 5 where hot air from the heater 12 is easily blocked (below the electronic component 7), only the pattern 3 around the part is provided. A through hole 6 may be provided.

It is a principal part enlarged view which shows the structure of the electronic component mounting board | substrate 1 which concerns on this invention. FIG. 2 is a top view of an I direction for explaining the periphery of a land in FIG. 1. It is the schematic which shows the structure of the heating apparatus 10 when heating with respect to the circuit board 2. FIG. It is a figure which shows other embodiment of the circuit board.

Explanation of symbols

1 Electronic component mounting board 2 Circuit board 3 Pattern (first pattern)
4 patterns (second pattern)
5 Land 6 Through hole 7 Electronic component 8 Solder 15 Base substrate 15a Surface (one surface)
15b Back side (the other side)

Claims (4)

A base substrate made of an insulator;
A first pattern provided on one surface of the base substrate and made of a conductive layer;
Lands provided in the first pattern and coated with solder;
A second pattern formed on the other surface of the base substrate and made of a conductive layer;
An electronic component mounting board in which the first pattern and the second pattern are penetrated through a through hole,
2. The electronic component mounting board according to claim 1, wherein a plurality of the through holes are provided outside the land.  The electronic component mounting board according to claim 1, wherein the through hole is formed around the land. A base substrate, a first pattern made of a conductive layer provided on one surface of the base substrate, a second pattern made of a conductive layer provided on the other surface, and a land provided on the first pattern. In a method of manufacturing an electronic component mounting board in which an electronic component is mounted on an insulating circuit board by soldering,
Using the circuit board penetrating the base substrate, the first pattern and the second pattern through a through hole provided outside the land,
An application process for applying solder to the lands, an installation process for installing the electronic components on the lands, and heat applied to the other surface by heating from both sides of the circuit board on which the electronic components are installed And a heating step of transmitting to the land through the through hole.   The method for manufacturing an electronic component mounting board according to claim 3, wherein in the heating step, heating from the other surface of the circuit board is stronger than heating from one surface of the circuit board.

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