WO2008023403A1

WO2008023403A1 - Board

Info

Publication number: WO2008023403A1
Application number: PCT/JP2006/316384
Authority: WO
Inventors: Takehiro Motegi
Original assignee: Pioneer Corporation
Priority date: 2006-08-22
Filing date: 2006-08-22
Publication date: 2008-02-28

Abstract

A board (1), on to which electronic parts are soldered, includes projection parts (21) and recess parts (22) which are alternately formed in at least a part of the edge of the board at predetermined pitches and each of which has a solder land to which an electronic part is soldered. The board further includes bridging means (5) for bridging at least one pair of projecting parts (21) formed at the predetermined pitches.

Description

Specification

Substrate

Technical field

[0001] The present invention is a substrate for soldering an electronic component such as a flexible substrate, and suppresses an increase in the occurrence rate of defects while suitably ensuring workability when miniaturized. It relates to the technical field of possible substrates.

Background art

[0002] A flexible substrate, which is an example of this type of substrate, is a substrate made of polyimide film, liquid crystal polymer, glass “epoxy resin” or aramid film (hereinafter also referred to as “polyimide” as appropriate). Since it is used, it has flexibility. In other words, since it can be folded, it is often used for small products such as mobile phones and digital cameras that have limited mounting space.

[0003] When used for powerful products, various techniques for laying wiring as much as possible on a limited width on the substrate have been proposed in order to reduce the size. For example, there has been proposed a flat cable and a flat cable joining structure for preventing a solder bridge that can short-circuit the wiring (see Patent Document 1). It is preferable that the solder land at one end of the wiring laid out in this way has a width or an area that allows at least hand and solder to be easily performed. Therefore, it is effective to make the outer shape of one end of the flexible substrate into a mountain-and-valley shape and to provide solder lands alternately in the peaks and valleys. When configured in this way, shorting between solder lands can be prevented while securing the width or area of the solder lands. That is, the workability when it is miniaturized is preferably ensured.

[0004] Patent Document 1: JP-A-9 245856

Disclosure of the invention

Problems to be solved by the invention

[0005] However, if the outer shape of one end of the flexible substrate is made into a mountain-and-valley shape as described above, the defect occurrence rate may increase due to the problem of strength.

[0006] The present invention has been made in view of the above-mentioned problems, for example, and when it is miniaturized. It is an object of the present invention to provide a flexible substrate that can suppress the increase in the defect occurrence rate while suitably ensuring the workability of the above.

Means for solving the problem

[0007] In order to solve the above-mentioned problem, the substrate of the present invention is a substrate for soldering electronic components, and is alternately formed at a predetermined pitch on at least a part of the edge of the substrate. And the peak part and trough part which each have the solder land to which the said electronic component is soldered, and the bridge | crosslinking means which bridge | crosslinks at least one pair among the said peak parts formed at the said predetermined pitch.

[0008] According to the present embodiment, for example, the above-described problem power is solved as follows.

[0009] First, the substrate according to the present embodiment is a flexible substrate having an insulating force such as polyimide, and is a substrate for attaching electronic components.

[0010] Crests and troughs are alternately formed at a predetermined pitch on at least a part of the edge of the substrate. The “predetermined pitch” here is a force that is an interval determined based on the wiring layout extending toward the solder lands in the peaks and valleys, and does not need to be particularly limited. These peaks and valleys each have a solder land on which electronic components are soldered. When the peaks and valleys are formed in this way, short-circuit between the solder lands can be prevented while securing the width or area of the solder lands. In other words, workability when downsized is suitably secured.

However, according to the inventor of the present application, it has been found that there is a possibility that the following technical problems may occur in these peaks and valleys. For example, when a part is delivered, reflowed, or assembled, the crests are turned or broken, which may increase the defect occurrence rate compared to the case where crests and troughs are not formed.

[0012] Therefore, the bridging means bridges at least a pair of peaks formed at a predetermined pitch with, for example, a member similar to the substrate. Here, “crosslinking” means connecting a pair of peaks with a predetermined member. The mode of cross-linking in this way is to disperse the external force acting in the direction of turning or tearing one of the peaks at least to other peaks. As long as it is possible, there is no particular limitation. For example, a plurality of cross-linking means, in other words, “bridges” may be cross-linked per pair, The width of the bridge may be different for each pair. Then, this “bridge” may typically be bridged by skipping one of the adjacent mountain pairs or by arbitrary pairs. In any case, the external force acting on the mountain is dispersed, making it difficult to turn this mountain. In addition, when cross-linking is performed by the cross-linking means, the valley is substantially raised, or the height of the peak is substantially reduced, so that it is difficult for the foreign matter to be pulled to the peak.

[0013] Therefore, according to the present embodiment, it is possible to suppress an increase in the defect occurrence rate while favorably ensuring workability when downsized, which is very advantageous in practice.

[0014] In one embodiment of the substrate of the present invention, the crosslinking means is an insulator.

[0015] According to this aspect, the crosslinking means is an insulator such as polyimide. Therefore, it is possible to avoid short-circuiting between the solder lands of the bridged peaks.

[0016] In another aspect of the substrate of the present invention, the shape of the opening surrounded by the pair, the valley between the pair, and the bridging means for bridging the pair is arbitrary.

[0017] According to this aspect, the shape of the opening can be selected and used in various shapes such as a circle, a triangle, a quadrangle, a polygon, an ellipse, a semicircle, and an arbitrary curve. In other words, even if the shape of the opening portion is arbitrary, if it is cross-linked by the cross-linking means, the external force acting on the mountain portion is dispersed, and it becomes difficult to turn this mountain portion up and down.

In another aspect of the substrate of the present invention, the bridging means has an arch structure that warps in the height direction of the peak portion.

[0019] According to this aspect, since the bridging means has an arch structure that warps in the height direction of the peak portion, it can resist an external force by an axial force, a bending moment, and a shearing force. Therefore, the strength is increased as compared with the case where the bridging means has a linear single pillar structure.

[0020] It should be noted that the bridging means according to the present embodiment can adopt various structures such as a rigid frame structure rigidly joined to the mountain portion in addition to the arch structure described above.

[0021] In another aspect of the substrate of the present invention, the bridging means bridges portions that are a predetermined distance in the height direction from leading ends of the pair of crests.

[0022] According to this aspect, the portions that are lowered by a predetermined distance in the height direction from the tips of the pair of peaks are bridged by the bridging means. Here, the “predetermined distance” refers to, for example, the positional relationship between the bridged portion and the solder land, while the strength of the mountain portion is expected to improve. It may be determined by experiment or simulation as the distance at which the shortage is unlikely to occur, in other words, the distance that satisfies both the structural mechanical requirements and the electromagnetic requirements. In other words, the predetermined distance is typically zero and does not prevent the predetermined distance from being set to a value larger than zero due to other requests.

[0023] In another aspect of the substrate of the present invention, the solder land is formed so as to avoid the portion.

[0024] According to this aspect, the solder land is formed so as to avoid a portion that is cross-linked by the cross-linking means. In other words, the above-mentioned predetermined distance is determined as a distance exceeding the area occupied by the tip force solder land of the mountain portion. If a solder land is formed in this way, a short circuit is less likely to occur while an improvement in the strength of the mountain is expected, which is very advantageous in practice.

[0025] As described above, according to the substrate of the present embodiment, since the crests and troughs and the bridging means are provided, the workability when reduced in size is preferable while having a relatively simple configuration. It is possible to suppress an increase in the defect occurrence rate while ensuring the same.

[0026] The operation and other advantages of the present embodiment will be made clear by the following example force.

Brief Description of Drawings

FIG. 1 is a plan view showing a basic structure of a flexible substrate according to a comparative example.

FIG. 2 is a cross-sectional view in the I direction of a flexible substrate according to a comparative example.

FIG. 3 is a plan view showing a state where a crest of a flexible substrate is damaged according to a comparative example.

FIG. 4 is a plan view showing a basic structure of a flexible substrate according to the first embodiment.

FIG. 5 is a plan view showing a basic structure of a flexible substrate according to a second embodiment.

FIG. 6 is a plan view showing a basic structure of a flexible substrate according to a third embodiment.

FIG. 7 is a plan view showing a basic structure of a flexible substrate according to a fourth embodiment.

FIG. 8 is a plan view showing a basic structure of a flexible substrate according to a fifth embodiment.

Explanation of symbols

[0028] 1 Flexible substrate

2 Board

201 base 202 coverlay

21 Yamabe

22 Tanibe

23 Damaged mountain

3 Conductive part

4 Nordland

41 Solder

5, 51, 52, 53 Bridge

6 opening

BEST MODE FOR CARRYING OUT THE INVENTION

[0029] Hereinafter, the best mode for carrying out the present invention will be described in each embodiment in order with reference to the drawings.

[0030] (1) First Example

A flexible substrate, which is an example of a substrate according to the first embodiment, will be described with reference to FIGS.

First, a basic structure of a flexible substrate according to a comparative example will be described with reference to FIG. FIG. 1 is a plan view showing a basic structure of a flexible substrate according to a comparative example.

In FIG. 1, a flexible substrate 1 according to a comparative example includes a substrate 2, a conductive portion 3, and a node land 4.

[0033] The flexible substrate 1 has flexibility. In other words, it can be folded.

Therefore, it is used for small products such as mobile phones and digital cameras where the mounting space is limited.

[0034] The substrate 2 is an insulator and includes a flexible material, for example, a polyimide film using polyimide, a liquid crystal polymer, a glass / epoxy resin, or a amide film.

The conductive portion 3 is an electronic component lead formed on the substrate 2, and is used for the surface of the copper wire subjected to preliminary soldering. This spare solder includes Sn, Ni—Pd direction force Sn -Preferable for environmental measures compared to Pb.

Here, due to a demand for miniaturization, the outer shape of one end of the substrate 2 forms a mountain-valley shape in order to spread as many conductive portions 3 as possible in a limited width on the substrate 2. That is, the substrate 2 has alternately the ridges 21 that are examples of the “peaks” according to the present invention and the valleys 22 that are examples of the “valleys” according to the present invention, for example, at an lmm pitch. A plurality of conductive portions 3 correspond to each of the valley portions 22.

The solder land 4 is provided with cream solder, and is electrically connected to the plurality of conductive portions 3 at the peak portion 21 or the valley portion 22. Therefore, the adjacent solder lands 4 are spatially separated, and each of the conductive portions 3 or the solder lands 4 is short-circuited, so-called solder bridge is prevented. At this time, since the width or area of the solder land 4 can be secured, manual soldering is facilitated.

Next, with reference to FIG. 2, a description of the cross-sectional view of the flexible substrate 1 will be given. FIG. 2 is a cross-sectional view of the flexible substrate in the I direction (see FIG. 1) according to the comparative example.

As shown in FIG. 2 (a), the flexible substrate 1 includes, for example, a base 201 having a polyimide film force, a conductive portion 3, and a force burley 202 having a polyimide film force and protecting the conductive portion 3, for example. Are laminated. A solder land 4 exposed for soldering is formed at the tip of the conductive portion 3, and solder 41 is attached to the conductive portion 3 in the solder land 4. Therefore, as shown in FIG. 2 (b), for example, the soldering object such as another flexible substrate 10 and the solder land 4 can be soldered.

[0040] As described above with reference to FIGS. 1 and 2, the flexible substrate 1 according to the comparative example has the ridges 21 and the valleys 22, so that the width or area of the solder lands 4 is secured, In addition, it is possible to prevent short-circuiting between solder lands. The solder land 4 is used for soldering with another flexible substrate.

[0041] However, if the shape is such a valley and valley, as shown in Fig. 3, due to strength problems, it is necessary to supply parts, reflow, and assembly (hereinafter also referred to as parts delivery). The ridge 21 may be damaged. For example, there is a risk that the mountain part 21 will turn or may be broken, resulting in an increase in the defect rate. FIG. 3 is a plan view showing a state in which the peak portion of the flexible substrate is damaged according to the comparative example. In FIG. 3, as indicated by the damaged peak portion 23, the peak portion 21 of the flexible substrate 1 is damaged. For this reason, the solder land 4 is not formed in the damaged peak portion 23. In other words, cream solder is not applied.

Therefore, the structure of the flexible substrate 1 according to the present embodiment is the structure shown in FIG. FIG. 4 is a plan view showing the basic structure of the flexible substrate according to the first embodiment. In FIG. 4, the same components as those of the flexible substrate 1 in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

In particular, in this embodiment, as shown in FIG. 4, the flexible substrate 1 according to this embodiment further includes a bridging portion 5 in order to avoid damage to the peak portion 21.

The cross-linking part 5 is an example of the “cross-linking means” according to the present invention, and cross-links at least some of the adjacent peak parts 21. Typically, all adjacent peaks 21 are bridged. Therefore, compared to the case where the bridge part 5 is not provided, the probability that the foreign substance is attracted to the peak part 21 at the time of delivery of the parts is reduced. In addition, even if a foreign object is attracted to the peak 21, the cross-linked peaks 21 support each other, and the strength increases. Therefore, it is possible to prevent damage such as turning over, and it is possible to suppress an increase in the defect occurrence rate.

Note that the bridging portion 5 is an insulator similar to the substrate 2 that avoids short-circuiting of the solder lands 4. That is, the bridging portion 5 and the mountain portion 21 are integral and are so-called rigidly joined to form a ramen structure. Therefore, it can resist external force by axial force, bending moment, and shear force.

[0047] Further, since there is the bridging portion 5, it is possible to expand these solder lands 4 in the width direction while paying attention not to short-circuit the solder lands 4 belonging to the adjacent mountain portions 21. Therefore, a working space is secured and hand soldering is further facilitated.

As described above with reference to FIGS. 1 to 4, since the flexible substrate 1 according to the present embodiment further includes the bridging portion 5, damage to the peak portion 21 can be avoided. More specifically, by ensuring the width or area of the solder lands 4 and preventing the solder lands 4 from shorting together, the workability at the time of miniaturization is suitably secured while the defect occurrence rate is increased. Can be suppressed. At this time, the main difference between the comparative example and the present example is the design of the bridging portion 5, and the other manufacturing steps may be the same. [0049] (2) Second embodiment

A flexible substrate, which is an example of a substrate according to the second embodiment, will be described with reference to FIG. FIG. 5 is a plan view showing the basic structure of the flexible substrate according to the second embodiment. In FIG. 5, the same components as those of the flexible substrate 1 in FIG. 4 are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

[0050] Particularly in the present embodiment, as shown in Fig. 5, the bridging portion 5 bridges a part of the adjacent peak portions 21. In other words, not all of the adjacent peaks 21 are bridged.

[0051] As described above with reference to FIG. 5, if both of the adjacent ridges 21 are bridged with one of the ridges 21, a defect occurs even if the bridge is not bridged with the other ridge 21. The increase in rate can be suppressed to a greater or lesser extent.

[0052] (3) Third Example

A flexible substrate, which is an example of a substrate according to the third embodiment, will be described with reference to FIG. FIG. 6 is a plan view showing the basic structure of the flexible substrate according to the third embodiment. In FIG. 6, the same components as those of the flexible substrate 1 in FIG. 4 are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

In the present embodiment, in particular, as shown in FIG. 6, the width of the bridging portion 51, in other words, the area of the opening portion 6 surrounded by the peak portion 21, the valley portion 22, and the bridging portion 51 is shown in FIG. Compared to that in 4 is different. Specifically, the width of the bridging portion 51 is narrowed, and the opening 6 is extended in the height direction of the peak portion 21. As a result, it is possible to reduce the amount of material used for the bridging portion 51 and reduce the cost and weight, while suppressing the increase in the defect occurrence rate to a greater or lesser extent. On the contrary, if importance is attached to the strength, the width of the bridging portion 51 may be widened, and the opening 6 may be shortened in the height direction of the peak portion 21.

As described above with reference to FIG. 6, the shape of the opening 6 of the flexible substrate 1 according to the present embodiment may be variable according to the design concept. For example, in addition to the above-described aspects, the shape may be selected from various shapes such as a circle, a triangle, a quadrangle, a polygon, an ellipse, a semicircle, and an arbitrary curve, so that the degree of freedom in layout is improved.

[0055] (4) Fourth embodiment

The flexible substrate, which is an example of the substrate according to the fourth embodiment, is shown in FIGS. This will be described with reference to FIG. FIG. 7 is a plan view showing the basic structure of the flexible substrate according to the fourth embodiment. In FIG. 7, the same components as those of the flexible substrate 1 in FIG. 4 are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

In this embodiment, in particular, in FIG. 7, the bridge portion 52 is an arch structure that warps in the height direction of the mountain portion 21 that is not a linear single-column structure. Therefore, it can resist external force by axial force, bending moment, and shear force, so the strength is increased compared to the single pillar structure.

As described above with reference to FIG. 7, the bridging portion 52 according to the present embodiment does not need to have a linear one-column structure. In addition to the arch structure described above, various structures that increase the strength or facilitate the soldering of the term solder can be employed.

[0058] (5) Fifth embodiment

A flexible substrate, which is an example of a substrate according to the fifth embodiment, will be described with reference to FIG. FIG. 8 is a plan view showing the basic structure of the flexible substrate according to the fifth embodiment. In FIG. 8, the same components as those of the flexible substrate 1 in FIG. 4 are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

In this embodiment, in particular, in FIG. 8, the portions that are lowered by a predetermined distance in the height direction of the ridge portion 21 from the tip of the ridge portion 21 adjacent to the bridging portion 53, that is, the middle portions of the ridge portion 21. Are cross-linked. More specifically, the parts of the mountain 21 where the solder land 4 is not formed are bridged. Alternatively, the solder lands are formed to avoid cross-linked portions. Therefore, it is possible to prevent the solder of the solder land 4 in the mountain portion 21 from being short-circuited via the bridge portion 53 in FIG.

[0060] As described above with reference to FIG. 8, according to the flexible substrate 1 of this example, it is more preferable to short-circuit between solder lands while suppressing an increase in the occurrence rate of defects such as turning over. Can be prevented.

It should be noted that the present invention is not limited to the above-described embodiments, but can be appropriately modified within the scope of the appended claims and the entire description. The accompanying flexible substrate is also included in the technical scope of the present invention.

Industrial applicability The substrate according to the present invention can be used as a substrate for attaching electronic components such as a flexible substrate, and is also mounted on an information recording device such as a BD (Blu-ray Disc) recorder. Is available.

Claims

The scope of the claims

[1] A board for mounting electronic components,

Crests and troughs that are alternately formed at a predetermined pitch on at least a part of the edge of the substrate and have solder lands on which the electronic components are soldered, respectively.

A bridging means for bridging at least a pair of the peaks formed at the predetermined pitch; and

A substrate characterized by comprising:

[2] The cross-linking means is an insulator.

The substrate according to claim 1.

[3] The shape of the opening surrounded by the pair, the valley between the pair, and the bridging means for bridging the pair is arbitrary.

The substrate according to claim 1 or 2, wherein

[4] The bridging means is an arch structure that warps in the height direction of the peak portion.

The substrate according to claim 1 or 2, wherein

[5] The bridging means bridges portions that are separated by a predetermined distance in the height direction from the ends of the peak portions of the pair.

The substrate according to claim 1 or 2, wherein

[6] The solder land is formed so as to avoid the portion.

The substrate according to claim 5.