JPH0453185A - Method and jig for preventing warpage of master printed circuit board - Google Patents

Abstract

PURPOSE:To effectively prevent particularly warpage of center of a master printed circuit board by engaging a warpage preventing jig at its connecting part with a frame, laterally installing it between frames at the lower surface side of the board, extending at the support along a slid, and supporting its bridge. CONSTITUTION:A slender platelike warpage preventing jig 30 has connecting parts 31, 32 at both ends, and a bridge support 33 between the parts 31 and 32. The jig 30 is engaged with frames 2-1, 2-2 opposed to the parts 31, 32 of both ends, and laterally installed between the frames 2-1 and 2-2 at the lower surface side of a master board 1. The jig 30 is engaged at the parts 31, 32 of both ends with the frames 2-1, 2-2, laterally installed between the parts 2-1 and 2-2 along the lower surface of the board 1, and the supports 33 are disposed in height in contact with the bridges 5. Thus, the bridges 5 are supported in contact with the support 33, and reinforced. Thus, the bridge 5 is supported by the support 33, and not bent. Accordingly, slave board group at the center of the board 1 is not warped, and held in an original horizontal state.

Description

[Detailed Description of the Invention] [Summary] A method and a jig for preventing warping of a parent printed circuit board in the process of manufacturing a printed circuit board assembly using a multi-piece method, and a jig for preventing warpage of the parent printed circuit board, particularly in the center thereof. In order to reliably prevent the parts from warping, a plurality of child printed circuit boards are partitioned by grid-shaped slits inside the surrounding frame, and are partially connected by bridge parts that cross the slits. The present invention is a method for preventing warping of a parent printed circuit board provided in a state in which the frame is held in place, and the method includes locking portions for locking the frame at both ends, and supporting the bridge portion between the locking portions at both ends. A warp prevention jig having a support part is suspended horizontally between the frames on the lower surface side of the parent printed circuit board with its locking part locked to the frame, and the support part is connected to the slit. The bridge portion is configured to extend along the bridge portion and support the bridge portion.

[Industrial application field]

The present invention provides a method for producing multiple printed circuit board assemblies.
The present invention relates to a method for preventing warpage of a parent printed circuit board during manufacturing processes, and a jig for preventing warpage.

One method for manufacturing relatively small printed circuit board assemblies is a multi-chip method that effectively increases productivity.

FIG. 8 shows an example of a method for manufacturing a printed circuit board assembly using multiple pieces.

In this method, a synthetic resin parent printed circuit board 1 shown in FIG. 9 is used.

This parent printed circuit board (hereinafter referred to as a parent board) 1 is arranged vertically and horizontally in a surrounding rectangular frame 2 consisting of frame portions 2-3 to 2-4 and an area surrounded by this frame 2. It also includes a large number of child printed circuit boards (hereinafter referred to as child boards) 3.

Each child board 3 is divided by slits 4 in a checkerboard pattern, and is partially connected by a thin bridge portion 5 that crosses the slits 4.

In FIG. 8, first, cream solder is printed on the surface 1a of the parent board 1, that is, on the surfaces 3a of all the daughter boards 3 (step 10).

Next, apply epoxy adhesive to the surface 1a (step 11), mount the surface mount components on all slave boards 3 (step 12), and heat to about 150°C for about 1 minute to harden the adhesive. (Step 13).

Thereafter, the substrate 1 is turned over, and cream solder is printed on the back surface, which is now the upper surface (step 14). Furthermore, surface mount components are mounted (step 15).

Next, solder reflow (approximately 230° C., approximately 10 seconds) is performed (step 16), and components are mounted on both sides of all slave boards 3.

Finally, the bridge part 5 is cut and divided into each sub-board surface (step 17), to obtain a printed circuit board assembly having a structure in which components are mounted on the sub-screens of the sub-board 3.

This is incorporated into the casing to complete the electronic circuit module.

In the above manufacturing process, the large parent substrate 1 is handled until the dividing step 17.

As shown in FIG. 9, this parent board I is transported with the left and right frames 2-1 and 2-2 supported on transport belts 20 and 21, respectively, in order to avoid interference with the daughter board 3. .

In the above adhesive curing step 13 and solder reflow step 16, the parent board 1 is heated to a temperature higher than its softening temperature, and the bridge portion 5 softens and bends under the weight of the daughter board 3, causing the central portion of the parent board l to soften. bends downward in a convex state.

For example, if it bends in step 13, printing defects of cream solder may occur in the next step 14, or
5, component displacement defects may occur.

Also, the finished printed circuit board assembly itself may warp.
There is also a risk that it will not be possible to properly incorporate it into the case.

Therefore, it is necessary to use an appropriate jig to prevent the parent substrate 1 from warping during the manufacturing process.

Furthermore, in recent years, there has been a trend to increase the number of daughter boards in order to further improve productivity. In this case, the mother board becomes large and is likely to warp.

Therefore, a method for preventing warpage is required to have a structure that can accommodate an increase in the size of the parent substrate.

[Conventional technology]

Conventionally, as shown in FIGS. 10 and 11, the cross section was U.
A jig 25°26 bent into a letter shape is attached to the main board 1.
sandwiched between the front and rear frames 2-3°2-4 in the transport direction,
Prevents warping.

[Problem to be solved by the invention]

In the conventional method, the frame portion 1. ．． 1. The mechanical strength of the frame portion 2-, which spans between the conveyor belts 20 and 21, is strengthened.
2.2-4 warping is prevented.

However, the mechanical strength of the bridge portion 5 is not reinforced in any way, and it is difficult to sufficiently prevent the child board group within the frame 2 from warping.

The present invention relates to a method for preventing warpage of a parent printed circuit board and a warpage prevention jig that makes it possible to reliably prevent warpage, particularly in the central portion of the parent printed circuit board.

[Failure to solve the problem]

The present invention provides a parent printed circuit board in which a plurality of child printed circuit boards are provided inside a surrounding frame in a state in which a plurality of child printed circuit boards are partitioned by slits in a grid pattern and are partially connected by bridge parts that cross the slits. A method for preventing warpage of a warpage, comprising locking portions for locking the frame at both ends, and a support portion for supporting the bridge portion between the locking portions at both ends. The tool is suspended horizontally between the frames on the lower surface side of the parent printed circuit board with its locking portions being locked to the frame, and the supporting portion extends along the slit portion to form the bridge portion. It is designed to support.

[Effect]

Since each bridge is supported by a jig suspended horizontally between the frames, even if the size of the parent printed circuit board increases, the group of child printed circuit boards within the frame is prevented from warping. .

〔Example〕

FIGS. 1 and 2 each illustrate a method for preventing warpage of a parent printed circuit board according to an embodiment of the present invention.

As shown in FIG. 3, reference numeral 30 is a warpage prevention jig made of heat-resistant metal and shaped like an elongated plate, and has locking portions 31 and 32 on both ends. The shape has a bridge support part 33 in between.

As shown in FIGS. 1 and 2, this jig 30 has a frame portion 2-1.2-! with locking portions 31.32 at both ends facing each other. on the lower surface side of the parent board l.
2- is placed horizontally between them.

The support portion 33 extends along the slit 4.

The frame portions 2-+ and 2-* are supported by the conveyor belts 20.21 and are in a state where they are difficult to bend.

The jig 30 has the locking parts 31 and 32 at both ends connected to the frame part 2-
1.2-t, and while maintaining the same height position as the conveyor belt, the frame portion 2-1.2-
3, and each bridge support part 33 is at a height such that it comes into contact with each bridge part 5.

Therefore, each bridge portion 5 is in a state where it is in contact with the bridge support portion 33, supported and reinforced.

Further, as shown in FIG. 2, another jig 30A is provided at a different location parallel to the jig 30.

Therefore, even if the bridge portion 5 is softened in step 13.16 (FIG. 8), the bridge portion 5
is supported by the support portion 33 and does not bend. Therefore, the child substrate group at the center of the parent substrate l is not warped and is maintained in its original horizontal state.

Here, since the jigs 30 and 3OA support all the bridge parts 5 by horizontally spanning between the frame parts 2-1 and 2-2, the number of daughter boards increases and the size of the mother board l increases. Even in such a case, warpage between the slave boards can be reliably prevented.

Therefore, even when the size of the mother board 1 increases, it is possible to prevent the above-mentioned cream solder printing defects and component misalignment defects. It becomes possible to fully respond to

Furthermore, the jigs 30 and 3OA are located exclusively along the slit 4 and do not erode the component mounting area on the child board 3 at all.

Therefore, there is no area left to be cleaned, and there is no need to remove the jigs 30 and 3OA and clean the mother board 1 again.

Furthermore, the locking portions 31 and 32 are connected to the frame portion 1. ．． 2-2, and is in contact with the conveyor belt 20.21, so that it does not interfere with the conveyance of the mother board l.

Further, the jig 30 may be mounted horizontally between the frame portions 2-3, 2-4 on the front and rear sides in the transport direction of the parent board 1, and the same effect as described above can be obtained.

Next, regarding the dimensional relationship between the jig 30 and the parent board 1, the fourth
This will be explained with reference to the figures.

Depth 11. of locking portion 31.32. One of n2 is deep and the other is shallow (β+>12').

In addition, frame portion 1. ．． Dimensions between the inside of 12.

Then, the dimension L2 between the tip of the shallow locking part 32 and the deep part of the deep locking part 31 is determined to be L2<Ll.

Further, the dimension L3 between the tip of the shallow locking portion 32 and the tip of the deep locking portion 31 is determined such that L3>Ll.

As a result, the jig 30 is first moved diagonally in the direction of the arrow 40 and the locking portion 3 is moved as shown in FIG. 5(A).
1 through the slit 4 and engaged with the inside of the frame part 2, and then, in this state, rotate it as shown by the arrow 41 and pass the locking part 32 on the opposite side through the slit 4, as shown in the same figure (B). As shown in FIG. 1, it is attached as shown in FIG. 1 by facing the inside of the frame portion 2-2 and moving it as shown by arrow 42.

The jig 31 is removed from the mother board 1 by performing the procedure in reverse to the above.

In the manufacturing process shown in FIG.
It is adsorbed before step 13 and removed after step 13. It is also reattached before step 16 and removed after step 16.

FIG. 6 and FIG. 7 each show a modification of the warpage prevention jig.

The jig 50 shown in FIG. 6 has a structure in which two jig parts 51 and 51 having the same shape as the plate-shaped warpage prevention jig 30 are integrally provided in parallel.

The jig 60 shown in FIG. 7 includes two jigs 61 and 61 having the same shape as the above-mentioned plate-shaped warpage prevention jig 30, which are integrally provided in parallel and separated from each other, and an opening window 62 is provided between the two jigs 61 and 61. The configuration is as follows.

These jigs 50 and 60 are also attached in the same way as the jig 30 and have the same effects.

〔Effect of the invention〕

As explained above, according to the invention of claim 1, the warpage prevention jig is supported horizontally between the frames, and this horizontally suspended jig supports each bridge part, so that the bridge part This prevents bending even when softened by heat, and ensures that child printed circuit boards do not warp even when the size of the parent printed circuit board increases. It can be prevented.

According to the invention of claim 2, since the warpage prevention jig can be installed inside the support part while horizontally supporting the parent printed circuit board, it is possible to prevent the parent printed circuit board from warping and to prevent the parent printed circuit board from warping. Do not obstruct the transportation of

[Brief explanation of the drawing]

Fig. 1 is a diagram illustrating an embodiment of the method for preventing warpage of a parent printed circuit board according to the present invention; Fig. 2 is a perspective view of the parent printed circuit board with a warp prevention jig attached, viewed from below; Fig. 3; is a perspective view showing the warpage prevention jig in Figure 1, Figure 4 is a diagram explaining the dimensional relationship between the warpage prevention jig and the main printed circuit board, and Figure 5 is a diagram showing the installation procedure for the warpage prevention jig. FIG. 6 is a diagram showing one modification of the warpage prevention jig, FIG. 7 is a diagram showing another modification of the warpage prevention jig, and FIG. 8 is a diagram showing a modification of the warpage prevention jig. Figure 9 is a perspective view of the main printed circuit board in a conveyed state; Figure 1O is a perspective view of a conventional example; Figure 11 is a view seen from the direction of arrow M in Figure 10. be. shows.

Claims (2)

[Claims] (1) Inside the surrounding frame (2), a plurality of child printed circuit boards (3) are partitioned by grid-shaped slits (4) and are separated by bridge parts (5) that cross the slits (4). A method for preventing warping of a parent printed circuit board (1) that is connected to the frame (1), the method includes locking portions (31, 32) that lock the frame (2) at both ends. A warpage prevention jig (30) having a support part (33) for supporting the bridge part between the locking parts.
is suspended horizontally between the frame (2) on the lower surface side of the parent printed circuit board (1) with its locking portions (31, 32) locked to the frame (2), and the supporting portion ( 33) extends along the slit (4) to support the bridge portion (5). (2) Inside the surrounding frame (2), a plurality of child printed circuit boards (3) are partitioned by grid-shaped slits (4) and are separated by bridge parts (5) that cross the slits (4). This is a jig for preventing warping of the parent printed circuit board (1) that is connected to the frame (2), and has locking parts (31) at both ends that are removably locked inside the frame (2) , 32), and between the locking parts (31, 32) at both ends, the bridge part (
5), the locking portion is locked inside the frame (2), and the support portion (33) supports the bridge portion (5). A jig for preventing warpage of a parent printed circuit board, characterized in that it is attached to the bottom surface of a parent printed circuit board (1).