JP2002064267A - Method of mounting component on printed circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly hold electronic components, etc., for ensuring continuity of process steps for manufacturing a printed circuit board, when transport steps lie half way of the process steps. SOLUTION: For manufacturing a printed circuit board having mounted electronic components, process steps a-e are executed in this order, it is transported to the next processing place, and steps (f, g) is made to follow. The step (a) of applying cream solder to a board 2 having a printed conductor pattern, etc., using a metal mask, the step (b) of applying bonds (registered trademark) to mounting positions of the mounting components, the step (c) of mounting the components at designated positions, the step (d) of positioning the mounting components by the bonds, and the step (e) of soldering them in a reflow furnace are followed by the step (f) of mounting hole components and a step (g) of flow-soldering them, thus completing the printed circuit board 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board on which a large number of electronic components are mounted, and more particularly, to a component mounting that enables a mounted component to be stably held in a case where a transport process is interposed in a mounting process. About the method.

[0002]

2. Description of the Related Art In a printed circuit board provided by printing circuit wiring on an insulating substrate, electronic parts such as ICs and chip parts such as resistors and capacitors are provided at designated positions of the circuit of the conductor pattern. Is specified to be implemented.
If necessary, through holes or the like are provided at predetermined positions of the conductor pattern for mounting hole-mounted components or conducting to the conductor pattern on the back surface. In the case where the electronic component is mounted on the printed circuit board and the solder surface is subjected to flow soldering, for example, when applying a solder jet or soldering through molten solder, the following steps are taken. . Bond application, component mounting, bond hardening, flow soldering.

[0003] After the above steps (1) to (4), mounting components such as electronic components are positioned on the circuit board by bonding.
The board on which the mounted components are placed is soldered by a molten solder through a flow solder processing bath. As described above, the process of connecting the leads of the respective mounted components to the lands formed at the predetermined positions of the conductor pattern is performed to produce the printed circuit board.

[0004]

When mounting components on the printed circuit board, the above-described series of steps are performed continuously, and if the steps can be completed in one place, no particular problem occurs. However, the series of steps cannot be performed in the same place, and a transport step may be interposed between the bond hardening step and the flow soldering step. This is, for example, in the case where large electronic components are temporarily fixed with bonds, transported to another factory and mounted with hole mounted components, and then, after all the mounted components are flow soldered, Transport may be involved depending on the conditions of the process control. As described above, when a transportation step is interposed during the manufacturing process of the printed circuit board, the mounted components fixed by the bond may be peeled off due to an impact during transportation or the like, and the quality of the substrate is maintained. May cause problems. In addition, there is a problem that the work efficiency of the post-process deteriorates, for example, because the once-mounted component is peeled off, forcing the operation of mounting the detached component again.

[0005] The present invention addresses the problem that components once mounted on the substrate come off during transportation. After mounting surface-mounted components, the components are transported in a state where they are fixed and held once through a reflow furnace. The purpose is to provide a way to deal with.

[0006]

According to a first aspect of the present invention, there is provided a method of mounting components on a printed circuit board, wherein the following steps a to g are continuously performed. The component mounting step includes: a) a step of applying cream solder to the substrate using a metal mask; b) a step of applying a bond to a mounting position of the surface mount component on the substrate; and c) a conductor provided with the surface mount component on the substrate. Step of mounting at the designated position of the pattern, d Curing of the applied bond and positioning of the surface mount part, Step of introducing into e reflow furnace and soldering, Step of mounting of f hole part, and Step of g flow Soldering process. Consists of Further, in the invention of claim 2, the steps a to e are performed on one surface of the substrate, and thereafter, a process of mounting an electronic component is similarly performed from the back surface side. ,
g can be performed. And the processing step e
And the processing step f, the substrate on which the mounted components are mounted can be transported.

[0007] By manufacturing a printed circuit board through the above-described steps, it is possible to cope with a transport operation in a state where components are fixed and held on the board through the reflow furnace. Then, even if an impact or the like is applied to the substrate as a semi-finished product during the transportation, it is possible to prevent the components from falling off, and to immediately proceed to the subsequent processing step at the transportation destination.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the illustrated example. The example shown in FIG. 1 shows a part of the configuration of a general printed circuit board, and the printed circuit board 1 is made of glass-epoxy resin, paper-phenol, An insulating substrate 2 made of an insulator such as ceramics is used. Then, a conductor pattern is formed on the surface of the insulating substrate 2, a portion for arranging the electronic components 3 and 3a is provided at an arbitrary position, and a position for mounting an electronic component such as an IC is specified. Further, the electronic component 3,
In addition to the mounting designation portion 3a, a chip component mounting portion 4 and the like are formed in combination with the conductor pattern in order to mount small chip components such as capacitors and resistance components.
The conductor pattern provided on the insulating substrate 2 includes a large number of lands 5 for connecting leads protruding from the electronic component.
Also, through holes 6, 7 and the like are arranged at arbitrary positions, and are connected to the circuit of the conductor pattern.

When the printed circuit board 1 is formed, first, a conductive pattern is formed on the front and back surfaces of the insulating substrate 2, and an insulating paint is applied to both the front and back surfaces of the insulating substrate 2 so that the conductive pattern is not exposed. Is applied to form a solder resist layer 8 on the entire surface and cover it, but the insulating layer is not shown. Since the printed circuit board 1 is not configured as a so-called solder leveler board in which a conductor pattern on an insulating board is covered with a solder layer, an exposed portion such as a land is exposed on a copper surface because a copper material is exposed. Has the property of being easily oxidized. In recent years, a pre-flux substrate has been frequently used in place of the solder leveler substrate, and this type of substrate is configured such that a flux is applied to an exposed conductor pattern.

A conductor pattern (not shown) is formed on the surface of the insulating substrate 2 and a process of covering the solder resist layer 8 except for lands for connecting leads of electronic components is performed. Thereafter, in general, cream solder is applied to each land 5 of the electronic component 3 and the chip component mounting portion 4 using a metal mask to form a cream solder application portion 9 everywhere. An electronic component or a chip component is mounted at a position where the component mounting is designated. After mounting the electronic components and the like as described above, the insulating substrate 2 is heated at a predetermined temperature through a reflow furnace, so that the leads of the electronic components are applied to the lands on the substrate via the cream solder application section 9. Soldering to connect to the conductor pattern or through-hole circuit.

After connecting the electronic component mounted on one surface of the insulating substrate 2 to the conductor pattern, the electronic component is mounted on the back surface (second surface) of the insulating substrate 2 and the electronic component is The process of soldering the component leads
This is performed through a flow soldering bath. When soldering through the flow soldering bath, the through holes 6, 7
The lead of the hole-mounted component is inserted into a predetermined portion of the substrate, and when the flow soldering is performed, the lead of the hole-mounted component is electrically connected to the conductor pattern or the through hole formed on the back surface.

When mounting electronic components and the like on the insulating substrate 2, the printed circuit board 1 can be manufactured through the steps shown in FIG. In the example of the process shown in FIG. 2, the insulating substrate 2 used in correspondence with the processing step a is provided by printing a conductor pattern, a ground pattern, and the like on the front and back surfaces of the substrate. The circuit printed on the front and back surfaces of the insulating substrate 2 is covered with an insulating film such as a solder resist layer except for parts for mounting components such as lands.

In the example of the processing step shown in FIG. 2, in the processing step a, cream solder is applied to the land of the substrate by using a metal mask, and in the next processing step b, the surface mount component on the substrate is used. Then, a bond is applied to the mounting position of the electronic component 3 and the like, and in the processing step c, the surface mount component such as the electronic component 3 is mounted at the specified position of the conductor pattern provided on the substrate. Next, in processing step d, the applied bond is cured to position the surface-mounted component, and processing step e is performed.
Then, a soldering process is performed through a reflow furnace to fix and hold the surface mount component to the insulating substrate 2.

As described above, the surface mounted components such as the electronic components can be transported between factories while being fixedly held on the insulating substrate 2. Then, in the factory where the next processing is performed, in the processing step f, processing such as mounting of parts to be mounted by inserting leads into through holes, such as hole parts, and processing of mounting parts to be mounted from the back surface of the board are performed. With the components mounted as described above, in the processing step g, a flow soldering process is performed through a flow soldering processing tank to complete the printed circuit board 1. When a printed circuit board is prepared as shown in FIG. 2, as shown in FIG. 3, electronic components 3A... Is a process of mounting from the other surface (A surface) and performing flow soldering from the B surface.

In addition to the case where the electronic component is mounted on only one surface of the substrate as shown in FIG. 3, the electronic component is mounted on both the front and back surfaces of the substrate 2 as shown in FIG. Alternatively, a hole mounting component can be attached from one side. In the flowchart shown in FIG. 4, one surface (B
A process for mounting electronic components is performed on the surface (a) in the order of steps a to e. Thereafter, a process of attaching the electronic component is performed on the other surface (A surface) of the substrate 2 in the order of steps a to e, and the circuits of the electronic component are connected to the conductor patterns formed on the front and back surfaces, respectively. Then, the electronic components are soldered and fixed so that they can withstand the impact during transportation. The cream solder used on the A side is
It has a lower melting point than the cream solder used on the B side. Next, in the next factory where the product was transported, the hole-mounted components 4A ...
Are mounted from the other surface (A surface) and flow soldering is performed from the B surface to perform the mounting process.

When the printed circuit board 1 is manufactured through the steps shown in FIG. 4, the other surface (the A surface) of the substrate 2
Are performed in the order of steps a to e, and then steps a to e are performed on the B side, and the electronic components 3A are also mounted on the B side. .. Are implemented. Then, a process of connecting the circuit of the electronic component to each of the conductor patterns formed on the front and back surfaces is performed, and a process of soldering each electronic component is performed, so that the electronic components are fixed so as to withstand an impact during transportation. Next, in the next factory where the wafer is transported, the hole mounting components 4A are mounted from the other surface (surface A), and the surface is mounted by flow soldering from surface B, thereby performing the mounting process by soldering. To

When the printed circuit board 1 is manufactured by applying the processing steps of FIG. 2 or FIG. 4, even when a transportation step is interposed in a series of the processing steps,
The electronic components provided on the printed circuit board can be held and a process for preventing the metal surface of the exposed portion of the circuit from being oxidized can be performed, and the reliability of the completed printed circuit board can be favorably maintained. . Further, the printed circuit board manufactured as described above can easily protect the conductor pattern and the land against vibration applied during transportation, changes in environmental conditions, and the like.

[0018]

According to the present invention, the printed circuit board is manufactured through the above-described steps, and the components are fixed and held on the board through the reflow furnace.
Be able to cope with transportation work. Then, even if an impact or the like is applied to the printed circuit board during the transportation, it is possible to prevent the components from falling off, and to immediately proceed to the subsequent processing steps at the transportation destination. If cream solder is applied to areas where conductors are exposed to deal with transportation, the surface of the exposed metal may oxidize even after long-term storage. Therefore, it is possible to maintain good circuit reliability.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a configuration of a printed circuit board.

FIG. 2 is an explanatory diagram of a manufacturing process of a printed circuit board.

FIG. 3 is a side view of the printed circuit board.

FIG. 4 is an explanatory diagram of another example of the manufacturing process of the printed circuit board.

FIG. 5 is a side view of a printed circuit board created by the method of FIG. 4;

[Explanation of symbols]

1 printed circuit board, 2 insulating board, 3 electronic component, 4 chip component land, 5 land,
6.7 through hole, 8 solder resist layer,
9 Cream solder application part.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05K 13/04 H05K 13/04 Z

Claims (2)

[Claims] 1. A method for mounting components on a printed circuit board, wherein the following steps a to g are performed continuously. a process of applying cream solder to a substrate using a metal mask; b applying a bond to a mounting position of a surface mount component on the substrate; c mounting a surface mount component at a designated position of a conductor pattern provided on the substrate. D. Curing of the applied bond and positioning of surface mount components, e. Introducing it into a reflow furnace and soldering, f. Mounting process of hole components, g. Flow soldering process. 2. A method for mounting components on a printed circuit board, wherein the following steps are continuously performed. A A step of applying cream solder to a substrate using a metal mask on one surface of a printed circuit board; b A step of applying a bond to a mounting position of a surface mount component on a substrate; D) hardening the applied bond, positioning the surface mount component, e. Soldering through a reflow furnace, and b. Mounting the conductor pattern on the opposite surface of the printed circuit board. And the a-
e) A step of performing processing by the step according to e is performed, and thereafter, a mounting step of the f-hole component and a g flow soldering step are performed.