阅读说明：本技术 布线电路基板及其制造方法和布线电路基板集合体片 (Wired circuit board, method for manufacturing same, and wired circuit board assembly sheet ) 是由 笹冈良介 柴田直树 大薮恭也 于 2019-07-12 设计创作，主要内容包括：布线电路基板的制造方法包括：第1工序,在该第1工序中,准备布线电路基板集合体片,该布线电路基板集合体片包括：支承片；多个布线电路基板,该多个布线电路基板支承于支承片；以及接合部,其将支承片和多个布线电路基板连结起来,并具有平坦状的一侧面和在厚度方向上与一侧面隔开间隔地相对的另一侧面,该接合部具有另一侧面朝向一侧面凹陷而成的薄壁部；以及第2工序,在该第2工序中,在形成朝向厚度方向另一侧突出的毛边部的同时切断薄壁部。(The method for manufacturing the wired circuit board includes: a 1 st step of preparing a wired circuit board assembly sheet in the 1 st step, the wired circuit board assembly sheet including: a support piece; a plurality of wired circuit boards supported by the support sheet; and a joint portion which connects the support sheet and the plurality of wired circuit boards, and has a flat one-side surface and another side surface opposite to the one-side surface with a space therebetween in a thickness direction, the joint portion having a thin-walled portion in which the other side surface is recessed toward the one-side surface; and a 2 nd step of cutting the thin portion while forming a burr portion protruding toward the other side in the thickness direction in the 2 nd step.)

1. A method for manufacturing a printed circuit board, characterized in that,

the method for manufacturing the wired circuit board includes:

a 1 st step of preparing a wired circuit board assembly sheet in the 1 st step, the wired circuit board assembly sheet including: a support piece; a plurality of printed circuit boards supported by the support sheet; and a joining portion that joins the support sheet and the plurality of wired circuit boards, and has a flat one-side surface and another side surface opposed to the one-side surface with a space therebetween in a thickness direction, the joining portion having a thin-walled portion in which the other side surface is recessed toward the one-side surface; and

and a 2 nd step of cutting the thin portion while forming a burr portion protruding toward the other side in the thickness direction in the 2 nd step.

2. The method of manufacturing a wired circuit board according to claim 1,

in the step 2, the cutter is brought into contact with the one side surface.

3. The method of manufacturing a wired circuit board according to claim 2,

the support piece comprises a direct connection part for directly connecting the joint part,

the direct-coupling portion has a weak portion,

in the step 2, the fragile portion and the thin portion are cut at the same time.

4. The method of manufacturing a wired circuit board according to claim 3,

the weak portion includes a 2 nd thin portion and/or a through hole.

5. The method of manufacturing a wired circuit board according to claim 1,

in the step 2, the other side surface is irradiated with laser light.

6. The method of manufacturing a wired circuit board according to claim 1,

the wired circuit board has a recessed portion recessed inward from an outer peripheral edge when viewed in a thickness direction,

the thin portion is disposed in the recessed portion so as to be located more inward than an imaginary outer peripheral line along the outer peripheral edge when viewed in the thickness direction.

7. A wired circuit board assembly sheet characterized in that,

the wired circuit board assembly sheet includes:

a support piece;

a plurality of printed circuit boards supported by the support sheet; and

a joining section which joins the support sheet and the plurality of wired circuit boards, and which has a flat one-side surface and another side surface opposed to the one-side surface with a space therebetween in a thickness direction,

the joint portion has a thin portion in which the other side surface is recessed toward the one side surface.

8. A printed circuit board comprising a printed circuit board,

the wired circuit board has an outer peripheral portion,

the outer peripheral portion has a cut-off remaining portion protruding outward,

the cut-off remaining portion has:

a base end portion; and

a free end portion which is continuous with the base end portion from one end portion in a thickness direction of the base end portion and which is thinner than the base end portion in thickness,

the outer end edge of the free end portion has a burr portion projecting toward the other side in the thickness direction,

the burr portion overlaps the base end portion when projected in a projecting direction of the cut-off remainder portion.

Technical Field

The present invention relates to a wired circuit board, a method for manufacturing a wired circuit board, and a wired circuit board assembly sheet, and more particularly to a wired circuit board, a method for manufacturing a wired circuit board, and a wired circuit board assembly sheet used in the method for manufacturing a wired circuit board.

Background

Conventionally, the following methods are known: a circuit board is obtained by preparing a raw material substrate in which a plurality of circuit boards are connected by narrow webs, and then cutting the narrow webs to separate the circuit boards from the raw material substrate (see, for example, patent document 1).

These raw material substrates have one side surface and the other side surface as two flat surfaces opposed in the thickness direction.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2000-91733

Disclosure of Invention

Problems to be solved by the invention

However, when the narrow web sheet is cut, a burr is easily generated in the cut remaining portion of the narrow web sheet. Specifically, when a cutter blade is brought into contact with one side surface of the narrow piece to cut the piece, or a laser beam is irradiated to the other side surface of the narrow piece, a burr is likely to be generated which protrudes from the other side surface toward the other side in the thickness direction.

In this case, since the one side surface in the thickness direction of the circuit board including the cut-off surplus portion becomes uneven, the handling property of the circuit board is lowered, and there is a problem that the mounting property of the circuit board is lowered when the circuit board is mounted on another board so that the one side surface of the circuit board is brought into contact with the flat surface of the other board.

The invention provides a wired circuit board excellent in handling property and mounting property, a method for manufacturing the wired circuit board, and a wired circuit board assembly sheet.

Means for solving the problems

The present invention (1) includes a method for manufacturing a wired circuit board, including: a 1 st step of preparing a wired circuit board assembly sheet in the 1 st step, the wired circuit board assembly sheet including: a support piece; a plurality of printed circuit boards supported by the support sheet; and a joining portion that joins the support sheet and the plurality of wired circuit boards, and has a flat one-side surface and another side surface opposed to the one-side surface with a space therebetween in a thickness direction, the joining portion having a thin-walled portion in which the other side surface is recessed toward the one-side surface; and a 2 nd step of cutting the thin portion while forming a burr portion protruding toward the other side in the thickness direction in the 2 nd step.

In the method for manufacturing a wired circuit board according to the second aspect, the thin portion recessed toward the one side surface is cut in the second step 2, and therefore, even if the burr portion is formed so as to protrude toward the other side surface in the thickness direction, the burr portion can be positioned on the one side in the thickness direction with respect to the other side surface around the thin portion. Therefore, the reduction in the handleability of the wired circuit board can be suppressed, and the reduction in the mountability of the wired circuit board can be suppressed.

The present invention (2) includes the method for manufacturing a wired circuit board according to (1), wherein in the step 2, a dicing blade is brought into contact with the one side surface.

In the 2 nd step of the method for manufacturing a wired circuit board, since a dicing blade is used, the thin portion can be easily cut.

The present invention (3) includes the method for manufacturing a wired circuit board according to (2), wherein the support sheet includes a direct connection portion to which the joining portion is directly connected, the direct connection portion having a fragile portion, and the fragile portion and the thin portion are simultaneously cut in the 2 nd step.

However, the joint portion includes a direct connection portion having no weak portion, and when the direct connection portion and the thin portion are simultaneously cut in the 2 nd step, the cutter blade in contact with the thin portion can cut the thin portion with a relatively small shearing force, while the cutter blade in contact with the direct connection portion cannot cut a thick direct connection portion unless a shearing force larger than this is used. Further, since the shearing force acting on the thick direct coupling portion is likely to be larger than the shearing force acting on the thin portion, the difference between the shearing force acting on the direct coupling portion and the shearing force acting on the thin portion becomes excessively large, and as a result, the posture of the cutter blade at the time of cutting becomes unstable, and the cutting accuracy is likely to be lowered.

However, in the method of manufacturing the wired circuit board, since the direct connection portion has the weak portion, the cutting blade in contact with the weak portion can cut the weak portion with a relatively small shearing force. Therefore, the thin portion and the direct connection portion can be simultaneously cut with a relatively small shearing force using the cutter.

Further, the shearing force acting on the fragile portion can be made to be the same as the shearing force acting on the thin portion. Therefore, the posture of the cutting blade can be stabilized during cutting, and the reduction of cutting accuracy can be suppressed.

Further, since the pressure of the cutter blade contacting the thin portion is reduced, the amount of the burr portion protruding to the other side in the thickness direction can be reduced as much as possible. As a result, the reduction in the handleability of the wired circuit board can be further suppressed, and the reduction in the mountability of the wired circuit board can be further suppressed.

Further, since the load acting on the cutting blade can be reduced, the number of times of replacement of the cutting blade can be reduced, and as a result, the manufacturing cost can be reduced.

The invention (4) includes the method for manufacturing a wired circuit board according to (3), wherein the fragile portion includes a 2 nd thin portion and/or a through hole.

In the method of manufacturing a wired circuit board, since the fragile portion includes the 2 nd thin portion and/or the through hole, the fragile portion can be reliably cut even with a small shearing force.

The invention (5) includes the method for manufacturing a wired circuit board according to (1), wherein in the 2 nd step, the other side surface is irradiated with a laser beam.

In the second step 2 of the method for manufacturing a wired circuit board, the thin portion can be cut with high accuracy because a laser beam is used.

The present invention (6) includes the method for manufacturing a wired circuit board according to any one of (1) to (5), wherein the wired circuit board has a recessed portion recessed inward from an outer peripheral edge when viewed in a thickness direction, and the thin portion is disposed in the recessed portion so as to be located inward of an imaginary outer peripheral line along the outer peripheral edge when viewed in the thickness direction.

However, if the thin portion is located outside the virtual outer circumferential line in the 2 nd step, the thin portion is likely to become an obstacle when the wired circuit board is processed or mounted.

However, in this method for manufacturing a wired circuit board, since the thin portion is disposed in the recessed portion so as to be located inward of a virtual outer peripheral line along the outer peripheral edge when viewed in the thickness direction in the 2 nd step, the burr portion can be located inward of the virtual outer peripheral line. Therefore, the thin portion formed with the burr portion does not become an obstacle, and the decrease in the handleability and the mountability of the wired circuit board can be further suppressed.

The present invention (7) includes a wired circuit board assembly sheet, including: a support piece; a plurality of printed circuit boards supported by the support sheet; and a joining portion that joins the support sheet and the plurality of wired circuit boards, and has a flat one-side surface and another side surface facing the one-side surface at a distance in a thickness direction, the joining portion having a thin portion in which the other side surface is recessed toward the one-side surface.

In the wired circuit board assembly sheet, the joining portion has a thin portion in which the other side surface is recessed toward the one side surface, and therefore, when the thin portion recessed toward the one side surface is cut, the burr portion formed on the thin portion can be positioned on the thickness direction side with respect to the other side surface around the thin portion. Therefore, the reduction in the handleability of the wired circuit board can be suppressed, and the reduction in the mountability of the wired circuit board can be suppressed.

The present invention (8) includes a wired circuit board having an outer peripheral portion having a cut-off remaining portion protruding outward, the cut-off remaining portion including: a base end portion; and a free end portion that is continuous with the base end portion from one end portion in a thickness direction of the base end portion and has a thickness smaller than that of the base end portion, an outer edge of the free end portion having a burr portion protruding toward the other side in the thickness direction, the burr portion overlapping the base end portion when projected in a protruding direction of the cut-off remaining portion.

In this wired circuit board, since the burr portion overlaps the base end portion when projected in the projecting direction of the cut-off remaining portion, the burr portion is positioned on one side in the thickness direction with respect to the other side surface of the periphery of the thin portion. Therefore, the reduction in the handling property of the wired circuit board can be suppressed, and the reduction in the mounting property can be suppressed.

ADVANTAGEOUS EFFECTS OF INVENTION

With the wired circuit board, the method for manufacturing the wired circuit board, and the wired circuit board assembly sheet according to the present invention, it is possible to suppress a decrease in the handleability and the mountability of the wired circuit board.

Drawings

Fig. 1 is a plan view of one embodiment of a wired circuit board assembly sheet according to the present invention.

Fig. 2 is an enlarged bottom view of the bonding portion of the wired circuit board assembly sheet shown in fig. 1.

Fig. 3A and 3B are sectional views of the joint shown in fig. 2, fig. 3A showing a-a sectional view of fig. 2, and fig. 3B showing a B-B sectional view of fig. 2.

Fig. 4 is a bottom view of the wired circuit board separated from the wired circuit board assembly sheet of fig. 1.

Fig. 5 shows a C-C cross-sectional view of the wired circuit board of fig. 4.

Fig. 6 is a cross-sectional view showing a modification of the 1 st thin portion shown in fig. 3A.

Fig. 7A and 7B are bottom views of modified examples of the fragile portion shown in fig. 2, in which fig. 7A shows a modified example in which the fragile portion is constituted only by the 2 nd thin portion, and fig. 7B shows a modified example in which the fragile portion is constituted only by the 2 nd opening portion.

Fig. 8 shows a bottom view of a modification of the fragile portion shown in fig. 2 (a mode in which the fragile portion has two 2 nd openings and 1 nd thin portion).

Detailed Description

One embodiment of a wired circuit board, a method for manufacturing a wired circuit board, and a wired circuit board assembly sheet according to the present invention will be described with reference to fig. 1 to 5.

In fig. 1, the area indicated by the thick dotted line represents the area depicted in fig. 2. In fig. 2, a thick one-dot chain line depicts a line through which a cutter 27 (described later) passes. In fig. 2, the 1 st thin portion 5 (described later) and the 2 nd thin portion 11 (described later) are depicted with hatching in order to clearly show their relative positions.

As shown in fig. 1, the wired circuit board assembly sheet 1 has a substantially rectangular sheet shape extending in a longitudinal direction (a direction in which a wired circuit board 3 described later extends) (one direction of directions orthogonal to a thickness direction). As shown in fig. 3A and 3B, the wired circuit board assembly sheet 1 has one side surface 21 and the other side surface 22 that face each other in the thickness direction. As shown in fig. 1 and 2, the wired circuit board assembly sheet 1 includes a support sheet 2, a wired circuit board 3, and a joining portion 4.

The support sheet 2 has the same outer shape as the outer shape of the wired circuit board assembly sheet 1 in a plan view. The support piece 2 has a substantially lattice shape in a plan view. As shown in fig. 3A and 3B, the support sheet 2 includes the above-described one side surface 21 and the other side surface 22.

As shown in fig. 1 and 2, a plurality of the 1 st openings 7 formed around the wired circuit board 3, which will be described later, are formed in the support sheet 2 so as to correspond to the wired circuit board 3. The support sheet 2 includes a direct coupling portion 9 to which the joint portion 4 is directly coupled. The plurality of direct connection portions 9 are formed on the support sheet 2 so as to correspond to the wired circuit board 3.

Examples of the material of the support sheet 2 include a metal material, and a resin such as polyimide. Preferably, a metal-based material is used. Examples of the metallic material include metallic elements classified into groups 1 to 16 in the periodic table, and alloys containing two or more of these metallic elements. The metal-based material may be any of transition metals and typical metals. More specifically, examples of the metallic material include a 2 nd main group metal element such as calcium, a 4 th sub group metal element such as titanium or zirconium, a 5 th sub group metal element such as vanadium, a 6 th sub group metal element such as chromium, molybdenum or tungsten, a 7 th sub group metal element such as manganese, an 8 th sub group (8 th column) metal element such as iron, an 8 th sub group (9 th column) metal element such as cobalt, an 8 th sub group (10 th column) metal element such as nickel or platinum, a 1 st sub group metal element such as copper, silver or gold, a 2 nd sub group metal element such as zinc, a 3 rd main group metal element such as aluminum or gallium, and a 4 th main group metal element such as germanium or tin. The metal-based material preferably includes an alloy, and more preferably includes a copper alloy.

The support sheet 2 may be a plurality of layers made of different kinds of materials.

The thickness of the support sheet 2 is, for example, 1 μm or more, preferably 10 μm or more, and is, for example, 10mm or less, preferably 1mm or less.

A plurality of wired circuit boards 3 are arranged on the support sheet 2 at intervals in the longitudinal direction and the width direction (the direction orthogonal to both the longitudinal direction and the thickness direction). Each of the wired circuit boards 3 is disposed in the 1 st opening 7 and is connected to the direct connection portion 9 of the support sheet 2 via the joint portion 4.

The wired circuit board 3 has a substantially rectangular plate shape in plan view along the longitudinal direction. Specifically, the wired circuit board 3 has an outer peripheral edge 15 having a substantially rectangular shape in plan view. That is, the outer peripheral edge 15 of the 1 wired circuit board 3 includes two 1 st edges opposed to each other with a space therebetween in the longitudinal direction and two 2 nd edges opposed to each other with a space therebetween in the width direction and connecting the two width direction edges of the two 1 st edges.

As shown in fig. 3A and 3B, the wired circuit board 3 has the one side surface 21 and the other side surface 22.

As shown in fig. 1 and 2, the wired circuit board 3 has a recessed portion 12 recessed inward from the outer peripheral edge 15. The plurality of recessed portions 12 are provided corresponding to the plurality of joining portions 4 described later. Specifically, the plurality of recessed portions 12 have portions cut out in a substantially rectangular shape from two 1 st ones of the outer peripheral end edges 15 toward the longitudinal direction inner side, respectively (that is, 1 st one of the 1 st end edges has 1 of the recessed portions 12), and portions cut out in a substantially rectangular shape from two 2 nd ones of the outer peripheral end edges 15 toward the width direction inner side, respectively (that is, 12 nd one of the 2 nd end edges has 1 of the recessed portions 12).

As shown in fig. 2, the recessed portion 12 is partitioned by two 1 st sides 23 continuous with the corresponding outer peripheral end edges 15 and a 2 nd side 24 connecting the recessed direction distal end edges of the two 1 st sides 23.

The two 1 st edges 23 are arranged facing each other with a space in a direction along the corresponding outer peripheral edge 15. For example, the two 1 st edges 23 are each at right angles to the corresponding peripheral end edge 15.

The 2 nd side 24 is located inside (in the recessed direction) the virtual outer peripheral line 6 along the outer peripheral end edge 15 at a distance from the virtual outer peripheral line 6. For example, the 2 nd side 24 is parallel to the imaginary outer peripheral line 6 along the corresponding outer peripheral edge 15.

The wired circuit board 3 includes a metal supporting layer (not shown), an insulating base layer (not shown), a conductive layer 25, and an insulating cover layer in this order in the thickness direction. In the wired circuit board 3, the metal supporting layer is formed on the other side surface 22 in the thickness direction (see fig. 3A), and covers the one side surface 21 in the thickness direction (see fig. 3A) of the insulating layer. The material of the metal support layer and the conductor layer 25 is the same as, for example, the metal-based material exemplified for the support sheet 2. The material of the base insulating layer and the cover insulating layer is the same as the resin exemplified for the support sheet 2, for example.

The size of the wired circuit board 3 can be appropriately set according to the application and purpose. The thickness of the wired circuit board 3 is, for example, 1 μm or more, preferably 10 μm or more, and is, for example, 10mm or less, preferably 1mm or less.

As shown in fig. 2, the relative length L1 between the two 1 st sides 23 is the length of the 2 nd side 24, and is, for example, 100mm or less, preferably 10mm or less, and is, for example, 0.01mm or more, preferably 0.05mm or more. The ratio (L1/L0) of the relative length L1 between the two 1 st edges 23 to the length L0 (see fig. 1) of the corresponding outer peripheral edge 15 is, for example, 100 or less, preferably 1 or less, and, for example, 2 × 10^－5Above, preferably 2 × 10^－4The above.

The length L2 of the 1 st side 23 is the distance between the imaginary outer peripheral line 6 and the 2 nd side 24, and is also the amount (depth) of depression of the depressed portion 12. The length L2 of the 1 st side 23 is, for example, 0.001mm or more, preferably 0.01mm or more, and is, for example, 10mm or less, preferably 1mm or less. Further, the ratio (L2/L0) of the length L2 of the 1 st side 23 to the relative length L1 of the two 1 st sides 23 is, for example, 2X 10^－6Above, preferably 2 × 10^－3The above is, for example, 1 or less, preferably 0.2 or less.

As shown in fig. 1 and 2, the number of the joint portions 4 is 4 corresponding to the number of the 4 recessed portions 12 provided in the 1 wired circuit board 3. The joint 4 extends across the 1 st opening 7 in a plan view, and connects the wired circuit board 3 and the support sheet 2. Specifically, the joint portion 4 is directly connected to a direct connection portion 9 (described later) of the support sheet 2 from the 2 nd side 24 of the recessed portion 12 so as to bridge the 1 st opening 7. The support sheet 2 supports the printed circuit board 3 in a suspended manner (hereinafter, referred to as shelves) at a joint 4 (described later) extending across the 1 st opening 7. More specifically, the joint portion 4 has a shape extending from the central portion of the 2 nd side 24 in the direction along the outer peripheral edge 15 toward the outside of the joint portion 4 (the opposite side to the recessed direction of the recessed portion 12), and then reaching the direct joining portion 9. The joint portion 4 has a substantially rectangular plate shape in plan view, which is long in the direction outward from the wired circuit board 3. As shown in fig. 3A and 3B, the joint portion 4 has the above-described one side surface 21 and the other side surface 22.

One side surface 21 of the joint 4 has a flat shape. The other side surface 22 of the joint portion 4 has a flat shape in a region outside the 1 st thin portion 5 (region other than the 1 st thin portion 5) to be described later.

The material and layer structure of the joint 4 are the same as those of the support sheet 2. Further, when the support piece 2 includes a metal-based material and the wired circuit board 3 includes a metal-based support layer, the joining portion 4 preferably includes a metal-based material, and specifically, the joining portion 4 is a metal-based plate including a metal-based material that connects the support piece 2 and the metal-based support layer of the wired circuit board 3.

As shown in fig. 2 and 3A, the joining portion 4 has a 1 st thin portion 5 as an example of a thin portion. The 1 st thin portion 5 is disposed at a distal end portion (inner end portion) of the joint portion 4 in the recessed direction of the recessed portion 12 (end portion on the side where the wired circuit board 3 is located). Specifically, the 1 st thin portion 5 is disposed in the recessed portion 12 so as to be located inward of the virtual outer peripheral line 6 along the outer peripheral edge 15 when viewed in the thickness direction.

The 1 st thin portion 5 is a concave portion (1 st concave portion) in which the other side surface 22 of the joining portion 4 is recessed toward the one side surface 21. The other side surface 22 of the 1 st thin-walled portion 5 includes a top surface 19 and two side surfaces 20.

The top surface 19 is arranged on one side in the thickness direction with respect to the other side surface 22 of the joint portion 4 around the 1 st thin-walled portion 5. Thus, the top surface 19 overlaps the junction 4 around the 1 st thin portion 5 and the wired circuit board 3 when projected in the inward and outward directions of the wired circuit board 3 (the recessed direction of the recessed portion 12). The top surface 19 has a substantially rectangular shape in bottom view along the outer peripheral edge 15.

The two side surfaces 20 are inner side surfaces extending from both inner and outer edges of the top surface 19 toward the other side in the thickness direction. The other end edges in the thickness direction of the two side surfaces 20 are connected to the other side surface 22 around the 1 st thin-walled portion 5. The two side surfaces 20 are disposed opposite to each other in a parallel manner and at substantially right angles to the top surface 19.

On the other hand, one side surface 21 of the 1 st thin portion 5 is continuous with the other side surface 22 of the joining portion 4 around the 1 st thin portion 5 to form 1 plane. That is, they are flush.

The size of the engaging portion 4 can be appropriately set according to the use and purpose. Specifically, as shown in fig. 2, a relative length L1 between the width (length in a direction orthogonal to both the direction in which the joint 4 extends and the thickness direction) L3 of the joint 4 and the two 1 st sides 23 is small, and a ratio (L3/L1) of L3 to L1 is, for example, 0.5 or less, preferably 0.3 or less, and is, for example, 0.05 or more, preferably 0.1 or more. Specifically, the width L3 of the joint 4 is, for example, 100mm or less, preferably 10mm or less, and is, for example, 10 μm or more, preferably 50 μm or more.

The width (length in the inward-outward direction) L4 of the 1 st thin portion 5 is, for example, 0.1 μm or more, preferably 1 μm or more, and is, for example, 10mm or less, preferably 1mm or less. The distance L5 between the 1 st thin portion 5 and the virtual outer circumferential line 6 (specifically, the distance between the side surface 20 disposed on the outer side of the two side surfaces 20 and the virtual outer circumferential line 6) is, for example, 0.01 μm or more, preferably 1 μm or more, and is, for example, 10mm or less, preferably 1mm or less.

The distance L6 between the 1 st thin portion 5 and the 2 nd side 24 (specifically, the distance between the side surface 20 disposed inside of the two side surfaces 20 and the 2 nd side 24) is, for example, 0.01 μm or more, preferably 1 μm or more, and is, for example, 10mm or less, preferably 1mm or less.

L4/[L4+L5+L6]For example, 1X 10^－3The content is preferably 0.1 or more, for example, 1 or less, preferably 0.8 or less.

L5/L2 is, for example, 1X 10^－3The content is preferably 0.1 or more, for example, 1 or less, preferably 0.8 or less.

L6/L2 is, for example, 1X 10^－3Above, preferably 0.1 or more, and further for example1 or less, preferably 0.8 or less.

As shown in fig. 3A, the thickness T1 of the 1 st thin portion 5 is, for example, 10mm or less, preferably 1mm or less, and is, for example, 1 μm or more, preferably 10 μm or more. The ratio (T1/T0) of the thickness T1 of the 1 st thin portion 5 to the thickness T0 of the portion around the 1 st thin portion 5 is, for example, 0.7 or less, preferably 0.4 or less, and is, for example, 0.01 or more, preferably 0.1 or more.

The depth D from the top surface 19 of the 1 st thin portion 5 to the other side surface 22 around the 1 st thin portion 5 is a value obtained by subtracting the thickness T1 of the 1 st thin portion 5 from the thickness T0 of the part around the 1 st thin portion 5 (T0 to T1). The depth D is, for example, 10mm or less, preferably 1mm or less, and is, for example, 1 μm or more, preferably 10 μm or more. The ratio (D/T0) of the depth D to the thickness T0 of the portion around the 1 st thin-walled portion 5 is, for example, 0.7 or less, preferably 0.4 or less, and is, for example, 0.01 or more, preferably 0.1 or more.

Next, the direct connection portion 9 will be described.

As shown in fig. 1 and 2, the direct connection portion 9 is a region of the support sheet 2 directly connected to the joint portion 4. Specifically, the direct connection portion 9 is a portion of the support sheet 2 that is disposed to face each other outside the respective recessed portions 12 of the wired circuit board 3.

The direct coupling portion 9 has a fragile portion 26. The fragile portion 26 has the 2 nd thin portion 11 and the 2 nd opening 10.

The 2 nd thin portions 11 are disposed at both ends of the direct connection portion 9 in the direction in which the outer peripheral edge 15 extends. As shown in fig. 3A and 3B, the 2 nd thin portion 11 has the same structure as the 1 st thin portion 5. That is, the 2 nd thin wall portion 11 specifically has a top surface 19 and two side surfaces 20. The top surface 19 of each of the two 2 nd thin portions 11 is disposed on one side in the thickness direction with respect to the other side surface 22 of the direct coupling portion 9 around the 2 nd thin portion 11, and the 2 nd thin portion 11 is a concave portion (2 nd concave portion) in which the other side surface 22 (top surface 19) of the direct coupling portion 9 is recessed toward the one side surface 21.

As shown in fig. 2 and 3A, the 2 nd opening 10 is disposed at an outer end of the direct connection portion 9 (opposite side to the recessed direction of the recessed portion 12). The 2 nd opening 10 is disposed outside the 1 st opening 7 so as to face the 1 st opening 7 with a gap therebetween. The 2 nd opening 10 has a substantially rectangular shape in plan view extending in parallel with the 1 st opening 7. The 2 nd opening 10 is an example of a through hole penetrating the direct coupling portion 9 in the thickness direction of the direct coupling portion 9.

Since the fragile portion 26 has the 2 nd opening 10 and the 2 nd thin portion 11, the fragile portion 26 is weaker than the peripheries of the 2 nd opening 10 and the 2 nd thin portion 11.

The width, thickness and depth of the 2 nd thin-walled portion 11 are the same as those of the 1 st thin-walled portion 5. The width and length of the 2 nd opening 10 can be appropriately adjusted according to the purpose and application.

In fig. 2, a thick one-dot chain line is a line through which a cutting blade 27 (described later) passes, and the line is a substantially rectangular line through the 1 st thin portion 5 and the fragile portion 26.

Next, a method of manufacturing the wired circuit board 3 from the wired circuit board assembly sheet 1 will be described.

First, this method includes a 1 st step of preparing the wired circuit board assembly sheet 1 and a 2 nd step of cutting the 1 st thin-wall portion 5.

In the first step 1, for example, a metal sheet (not shown) made of a metal material is prepared, and then a base insulating layer (not shown), a conductor layer 25, and a cover insulating layer are sequentially formed on one side of the metal sheet in the thickness direction, thereby manufacturing the wired circuit board 3. Then, the metallic sheet is opened to form the 1 st opening 7 and the 2 nd opening 10. Thereby, the support piece 2 and the joint 4 are formed. In addition, the 1 st thin portion 5 is formed in the joining portion 4, and the 2 nd thin portion 11 is formed in the support piece 2. In forming the 1 st and 2 nd thin portions 5 and 11, for example, half etching, laser processing, or the like is used, and from the viewpoint of mass productivity, half etching is preferably used.

Thus, the wired circuit board assembly sheet 1 is obtained.

Next, as shown in fig. 3A, in the 2 nd step, the 1 st thin portion 5 is cut by bringing the cutting blade 27 into contact with the one side surface 21 of the 1 st thin portion 5. At the same time, the cutter 27 is brought into contact with the one side surface 21 of the 2 nd thin portion 11 to cut the fragile portion 26. That is, the 1 st thin portion 5 and the fragile portion 26 are cut simultaneously.

Examples of the cutting blade 27 include a thomson blade, a rotatable disk-shaped cutting blade, and the like. From the viewpoint of simultaneously cutting the 2 nd thin portion 11 and the fragile portion 26, a thomson knife is preferable. For example, as shown by the thicker single-dot dashed line in fig. 2, the thomson blade has a ring shape in plan view. Specifically, the thomson blade has a substantially rectangular frame shape that can pass through the 1 st thin portion 5, the 1 st opening 7, and the fragile portion 26 (the 2 nd thin portion 11 and the 2 nd opening 10) in a plan view.

As shown in fig. 3A, in the 2 nd step, the dicing blade 27 is disposed on one side in the thickness direction of the wired circuit board assembly sheet 1, and then the dicing blade 27 is moved to the other side in the thickness direction to bring the dicing blade 27 into contact with the one side surface 21 of the 1 st thin portion 5 and the one side surface 21 of the 2 nd thin portion 11, which is not shown. Next, the cutting blade 27 is further moved to the other side in the thickness direction to reach the other side surface 22 of the 1 st thin portion 5 and the other side surface 22 of the 2 nd thin portion 11, thereby shearing (press-cutting) the 1 st thin portion 5 and the 2 nd thin portion 11. Thereafter, the cutting blade 27 is moved to the other side in the thickness direction of the other side surface 22 of the 1 st thin portion 5 and the other side surface 22 of the 2 nd thin portion 11.

As shown in fig. 5, in the 2 nd step, when the 1 st thin portion 5 and the 2 nd thin portion 11 (not shown in fig. 5) are cut by the cutting blade 27, a burr portion 28 is formed to protrude toward the other side in the thickness direction. Further, the burr 28 remains on the portion of the wired circuit board 3 and the joint portion 4 located at the 1 st thin portion 5 and the portion of the direct connection portion 9 located at the 2 nd thin portion 11.

The burr portion 28 is not necessary in nature because it causes a reduction in handling and mounting properties particularly in the wired circuit board 3, but is inevitably formed in the second step 2 of the manufacturing method described later. In this embodiment, since the burr portion 28 is formed in the 1 st thin-walled portion 5, the above-described problem can be solved, which will be described later.

Thereby, the joint 4 is separated from the support piece 2 around the direct connection portion 9 together with the direct connection portion 9. This causes the printed circuit board 3 to be separated from the support sheet 2. Specifically, as shown by a thick one-dot chain line in fig. 2, the joint portion 4 and the direct connection portion 9 having a substantially T-shape in a plan view are removed.

Next, the wired circuit board 3 separated from the support sheet 2 will be described with reference to fig. 4 and 5.

The wired circuit board 3 has an outer peripheral portion 14, and the outer peripheral portion 14 includes the outer peripheral edge 15 and 4 recessed portions 12. The outer peripheral portion 14 is not connected to the joint portion 4 (see fig. 2), that is, is already cut away from the joint portion 4, and the outer peripheral portion 14 further has a cut-off remaining portion 16 protruding outward from the recessed portion 12.

The cut-off remainder portion 16 has a base end portion 17 and a free end portion 18 which are integrated.

The base end portion 17 has a thickness T2 equal to the thickness T0 of the portion of the joint 4 located around the 1 st thin-walled portion 5.

The free end portion 18 is continuous with the base end portion 17 from one end portion in the thickness direction of the base end portion 17. One side surface 21 of the free end portion 18 is continuous with one side surface 21 of the base end portion 17. On the other hand, the other side 22 of the free end 18 has a top surface 19 and a side surface 20. The top surface 19 of the free end portion 18 is not continuous with the other side surface 22 of the base end portion 17. Thus, the free end portion 18 is thinner than the base end portion 17. The free end portion 18 has a shape that sags toward the other side in the thickness direction as going toward the outside. The outer edge 29 of the free end portion 18 has a burr portion 28 as a protruding end (tip end) that protrudes toward the other side in the thickness direction. The burr portion 28 overlaps the base end portion 17 when projected in the projecting direction of the cut residual portion 16. The burr portion 28 is located on one side in the thickness direction with respect to an imaginary plane 30 (one-dot chain line) along the other side surface 22 of the base end portion 17.

The free end portion 18 has a thickness T3 similar to the thickness T1 of the 1 st thin-walled portion 5 shown in fig. 3A. The thickness T3 of the free end portion 18 is thinner than the thickness T2 of the base end portion 17. The ratio (T3/T2) of the thickness T3 of the free end portion 18 to the thickness T2 of the base end portion 17 is, for example, 0.7 or less, preferably 0.4 or less, and is, for example, 0.01 or more, preferably 0.1 or more.

Thereafter, the printed circuit board 3 is mounted on another substrate not shown. The other substrate has a flat surface, and the other side surface 22 of the printed circuit board 3 is in contact with the flat surface, which is not shown.

In the second step 2 of the method of manufacturing the wired circuit board 3, as shown in fig. 3A, the first thin portion 5 recessed toward the one side surface 21 is cut, and thus even if the burr portion 28 protrudes toward the other side in the thickness direction, the burr portion 28 can be positioned on one side in the thickness direction with respect to the other side surface 22 around the first thin portion 5 because the burr portion 28 is formed on the first thin portion 5 as shown in fig. 5. Therefore, a decrease in the handleability of the wired circuit board 3 can be suppressed, and a decrease in the mountability of the wired circuit board 3 can be suppressed.

In the 2 nd step of the method for manufacturing the wired circuit board 3, the 1 st thin portion 5 can be easily cut off by using the dicing blade 27 as shown in fig. 3A.

However, the joint 4 includes the direct joining portion 9 having no fragile portion 26, and when the direct joining portion 9 is cut simultaneously with the 1 st thin portion 5 in the 2 nd step, the 1 st thin portion 5 can be cut by the cutting blade 27 in contact with the 1 st thin portion 5 with a relatively small shearing force, while the thick direct joining portion 9 cannot be cut by the cutting blade 27 in contact with the direct joining portion 9 unless a shearing force larger than this is used, which is not shown in the figure. Further, the shearing force acting on the thick direct connection portion 9 tends to become larger than the shearing force acting on the 1 st thin portion 5, and therefore, the difference between the shearing force acting on the direct connection portion 9 and the shearing force acting on the 1 st thin portion 5 becomes excessively large. As a result, the horizontal posture of the cutter 27 at the time of cutting becomes unstable, and cutting accuracy tends to be lowered.

However, in the method of manufacturing the wired circuit board 3, since the direct connection portion 9 has the fragile portion 26 as shown in fig. 2, the dicing blade 27 in contact with the fragile portion 26 can cut the fragile portion 26 with a relatively small shear force as shown in fig. 3A and 3B. Therefore, the 1 st thin portion 5 and the direct connection portion 9 can be simultaneously cut with a relatively small shearing force using the cutting blade 27.

The shearing force acting on the fragile portion 26 can be set to the same degree as the shearing force acting on the 1 st thin portion 5. Therefore, the posture of the cutting blade 27 at the time of cutting can be stabilized, and the reduction of cutting accuracy can be suppressed.

Further, since the pressing force of the cutting blade 27 in contact with the 1 st thin portion 5 is reduced, the amount of the burr portion 28 protruding to the other side in the thickness direction can be reduced as much as possible. As a result, a decrease in the handleability of the wired circuit board 3 can be further suppressed, and a decrease in the mountability of the wired circuit board 3 can be further suppressed.

Further, since the load acting on the dicing blade 27 can be reduced, the number of times of replacement of the dicing blade 27 can be reduced, and as a result, the manufacturing cost can be reduced.

In the method of manufacturing the wired circuit board 3, since the fragile portion 26 includes the 2 nd thin portion 11 and the 2 nd opening 10, the fragile portion 26 can be reliably cut even with a small shearing force.

However, if the 1 st thin portion 5 is located outside the virtual outer circumferential line 6 in the 2 nd step, the 1 st thin portion 5 is likely to become an obstacle when the wired circuit board 3 separated from the support sheet 2 is handled or mounted, and this case is not shown.

However, in this method for manufacturing the wired circuit board 3, as shown in fig. 2, in the 2 nd step, the 1 st thin-wall portion 5 is disposed in the recessed portion 12 so as to be located inward of the virtual outer peripheral line 6 along the outer peripheral edge 15 when viewed in the thickness direction, and therefore, the dicing blade 27 can be located inward of the virtual outer peripheral line 6. Therefore, the 1 st thin portion 5 formed with the burr portion 28 does not become an obstacle, and a decrease in the handleability and the mountability of the wired circuit board 3 can be further suppressed.

In the wired circuit board assembly sheet 1, since the joint portion 4 has the 1 st thin portion 5 in which the other side surface 22 is recessed toward the one side surface 21 as shown in fig. 3A, when the 1 st thin portion 5 recessed toward the one side surface 21 is cut as shown in fig. 5, the burr portion 28 formed on the 1 st thin portion 5 can be positioned on the thickness direction side of the other side surface 22 around the 1 st thin portion 5. Therefore, a decrease in the handleability of the wired circuit board 3 can be suppressed, and a decrease in the mountability of the wired circuit board 3 can be suppressed.

In addition, in the wired circuit board 3, since the burr portion 28 overlaps the base end portion 17 when projected in the projecting direction of the cut-off surplus portion 16, the burr portion 28 is positioned on one side in the thickness direction with respect to the other side surface 22 around the 1 st thin-walled portion 5. Therefore, a decrease in the handling property of the wired circuit board 3 can be suppressed, and a decrease in the mounting property can be suppressed.

Modification example

In the following modifications, the same members and steps as those of the above-described embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. In addition, each of the modifications can exhibit the same operational effects as the one embodiment, except for the specific description. Further, one embodiment and the modification can be combined as appropriate.

As shown in fig. 3A, the other side surface 22 of the 1 st thin portion 5 has the top surface 19 and the side surface 20, but may have the curved surface 13, for example, as shown in fig. 6. The curved surface 13 has a shape approaching the top surface 19 toward an intermediate portion (central portion) in the width direction (inner-outer direction).

In the modification shown in fig. 6, the thickness T1 of the 1 st thin-walled portion 5 is the shortest distance in the thickness direction between the one-side surface 21 and the curved surface 13.

In one embodiment, as shown in fig. 2, the 1 st thin portion 5 is located inward of the virtual outer circumferential line 6 along the outer circumferential edge 15, but for example, the 1 st thin portion 5 may be located outward of the virtual outer circumferential line 6, which is not shown.

In one embodiment, the wired circuit board 3 has the recessed portion 12, but the wired circuit board 3 may not have the recessed portion 12, for example, and this case is not illustrated. The cut-off remainder 16 is formed to protrude outward from the outer peripheral edge 15.

As shown in fig. 2, in one embodiment, the fragile portion 26 has both the 2 nd thin portion 11 and the 2 nd opening 10, but as shown in fig. 7A to 7B, the fragile portion 26 may have only either the 2 nd thin portion 11 or the 2 nd opening 10.

In the modification shown in fig. 7A, the fragile portion 26 does not include the 2 nd opening 10 (see fig. 2), but includes only the 2 nd thin portion 11. The 2 nd thin portion 11 has a shape of approximately japanese コ in a plan view, which is open to the 1 st opening 7.

In the modification shown in fig. 7B, the fragile portion 26 does not include the 2 nd thin portion 11 (see fig. 2), but includes only the 2 nd opening 10. The 2 nd opening 10 is formed with a plurality of slits, specifically, with needle-eye-shaped (japanese: ミシン mesh-shaped) slits. The slit has a shape of approximately japanese コ in a plan view, which opens toward the 1 st opening 7.

In one embodiment, as shown in fig. 2, the fragile portion 26 includes 12 nd opening portion 10 and two 2 nd thin-wall portions 11, but the number thereof is not limited thereto. For example, as shown in fig. 8, the fragile portion 26 may include two 2 nd opening portions 10 and 12 nd thin portion 11. The arrangement and shape of the 2 nd opening 10 and the 2 nd thin portion 11 in plan view shown in fig. 8 are the same as the arrangement and shape of the 2 nd thin portion 11 and the 2 nd opening 10 in plan view shown in fig. 2, respectively.

In one embodiment, as shown in fig. 2 to 3B, the direct coupling portion 9 includes the fragile portion 26, but for example, the fragile portion 26 may not be included, and this case is not shown. In this case, the cutting blade 27 may cut the 1 st thin portion 5, which is not shown.

In one embodiment, as shown in fig. 3A and 3B, in the 2 nd step, the dicing blade 27 is used, but for example, a laser may be used, and this case is not shown.

In this modification, the other side surface 22 is irradiated with a laser beam not shown. Specifically, a light source (not shown) is disposed on the other side in the thickness direction of the wired circuit board assembly sheet 1, and in the 2 nd step, the top surface 19 (the other side surface 22) of the 1 st thin-walled portion 5 is irradiated with laser light from the light source. As a result, the 1 st thin portion 5 is formed with the burr portion 28 protruding toward the other side in the thickness direction.

Examples of the laser include a laser capable of cutting the 1 st and 2 nd thin portions 5 and 11 simultaneously with the formation of the burr portion 28, and examples thereof include a gas laser, a solid laser, a liquid laser, and the like, and preferably include a gas laser. Examples of the gas laser include a carbon dioxide laser, a helium neon laser, an argon ion laser, a carbon dioxide laser, and a nitrogen laser, and a carbon dioxide laser is preferable.

In this modification, since laser light is used in the 2 nd step, the 1 st thin portion 5 can be cut with high accuracy.

The present invention is described in detail with reference to the accompanying drawings, which are incorporated in and constitute a part of this specification. Variations of the present invention that are obvious to those skilled in the art are intended to be encompassed by the following claims.

Industrial applicability

The wired circuit board assembly sheet is used for manufacturing a wired circuit board.

Description of the reference numerals

1. A wired circuit board assembly sheet; 2. a support piece; 3. a wired circuit board; 4. a joint portion; 5. 1 st thin-walled portion; 6. an imaginary outer peripheral line; 9. a direct joint; 10. a 2 nd opening part; 11. a 2 nd thin-walled portion; 12. a recessed portion; 14. a peripheral portion; 15. a peripheral end edge; 16. cutting off the remaining part; 17. a base end portion; 18. a free end portion; 21. a side surface; 22. the other side surface; 26. a fragile portion; 27. a cutting knife; 28. a burr part; 29. an outer end edge.