JP2008147328A - Flexible board, and its manufacturing method - Google Patents

Flexible board, and its manufacturing method Download PDF

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Publication number
JP2008147328A
JP2008147328A JP2006331532A JP2006331532A JP2008147328A JP 2008147328 A JP2008147328 A JP 2008147328A JP 2006331532 A JP2006331532 A JP 2006331532A JP 2006331532 A JP2006331532 A JP 2006331532A JP 2008147328 A JP2008147328 A JP 2008147328A
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Prior art keywords
land
base
flexible substrate
roll
sheet
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JP2006331532A
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Japanese (ja)
Inventor
Takashi Ichiyanagi
Shinobu Masuda
Seiichi Nakatani
Yoshihisa Yamashita
貴志 一柳
誠一 中谷
忍 増田
嘉久 山下
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Matsushita Electric Ind Co Ltd
松下電器産業株式会社
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Priority to JP2006331532A priority Critical patent/JP2008147328A/en
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Abstract

A flexible substrate capable of reliably connecting a land and a via of a wiring pattern is provided.
Each of the lands includes a base material having flexibility, vias that electrically connect an upper surface and a lower surface of the base material, and lands formed on the vias. Reference numeral 30 denotes a flexible substrate 100 having a shape in which the length of the base material 10 in the vertical direction (MD direction) is longer than the length of the base material 10 in the horizontal direction (TD direction). Furthermore, a resin layer is formed on the upper surface and the lower surface of the substrate, and each land is embedded in the resin layer. The vias connected to the lands are paste vias formed by filling with a conductive paste.
[Selection] Figure 3

Description

  The present invention relates to a flexible substrate and a method for manufacturing the same.

  With recent downsizing, weight reduction, thinning of electronic devices, and high-speed processing of electronic circuits, there is a strong demand for downsizing and higher frequency of electronic components. In order to cope with this, various mounting parts are mounted with higher density, thereby shortening the wiring length to cope with higher frequencies and smaller sizes. In portable electronic devices such as mobile phones, miniaturization, weight reduction, and thinning are one of the biggest issues (see, for example, Patent Document 1).

Under such circumstances, a flexible substrate is attracting attention as a thin printed circuit board capable of realizing high-density mounting (for example, Patent Document 2). As a conventional method for manufacturing a flexible substrate, first, an insulating sheet having a thickness of about 50 to 100 μm is prepared, holes for interlayer connection are formed in the insulating sheet by drilling or laser processing, and holes are formed using a printing method. Is filled with a conductive paste (so-called via formation). Next, by laminating metal foil (copper foil) on both surfaces of the insulating sheet and selectively etching the metal foil into a predetermined wiring pattern, a flexible substrate on which the predetermined wiring pattern is formed is obtained.
JP 2003-163422 A JP 2001-1111189 A

  Further, as a method for forming a wiring pattern of a flexible substrate, there is a method of forming a wiring pattern by transfer as well as the above-described etching method. A method of forming a wiring pattern by transfer will be described with reference to FIGS.

  First, as shown in FIG. 1A, a sheet base material 510 having vias 520 formed at predetermined positions is prepared, and predetermined wiring patterns 532 are provided above and below the sheet base material 510. A carrier sheet 540 is disposed. A resin layer 514 is formed on the upper and lower surfaces of the sheet base material 510. Next, as shown in FIG. 1B, alignment is performed so that the lands 530 of the wiring pattern 532 arranged on the carrier sheet 540 and the vias 520 of the sheet base material 510 are arranged to face each other. Run the press. At this time, the wiring pattern 532 (and the land 530 thereof) is embedded in the resin layers 514 provided on both surfaces of the sheet base material 510 by pressure generated by hot pressing. Thereafter, when the carrier sheet 540 is peeled off, as shown in FIG. 1C, a flexible substrate on which the wiring pattern 532 is formed by transfer is completed.

  In this way, in the formation of the wiring pattern by transfer, it is not necessary to perform wet etching directly on the sheet base material, so that it is possible to eliminate the possibility that a residue such as an etching solution exists on the surface of the flexible substrate.

  The present inventor considered that the flexible substrate described above could be efficiently mass-produced by using the roll-to-roll method, and studied the production of the flexible substrate by the roll-to-roll method. In the roll-to-roll system, the main material of the flexible substrate is supplied in a roll state (that is, a long and rolled state), and processing can be continuously performed in the roll state. The transfer of the wiring pattern by the roll-to-roll method can be executed as shown in FIG.

  First, the sheet base material 510 having a resin layer formed on both sides is fed from the roll 600 in the direction of the arrow 900, and then a transfer process is performed by hot pressing of the flat plate 620. The carrier sheet 540 on which the wiring pattern 532 is arranged is sent out from the roll 640 by the rotation of the roll 640, and the wiring pattern 532 is transferred to the resin layer 514 by hot pressing of the flat plate 620, and then the carrier sheet 540 is rolled by the roll 660. It is wound up. The sheet base material 510 after the transfer process on which the wiring pattern 532 is formed is again wound into a roll shape by the roll 680 and delivered to the next process.

  As described above, in the roll-to-roll method, the manufacturing apparatuses are connected to each other, and the substrate continuously flows between the apparatuses, so that labor and the like associated with conveyance can be greatly reduced. In addition, automation of the production line is facilitated, and a flexible substrate can be produced with high production efficiency.

  However, the inventor of the present application considered that when the wiring pattern is transferred by the roll-to-roll method, the alignment of the land and the via of the wiring pattern may not be performed well. In the roll-to-roll method, it is necessary to align the sheets while feeding them from the roll state, and therefore it is unexpectedly difficult to align the sheets. In particular, when positioning is performed along the traveling direction of each sheet (so-called MD direction), the control for returning the sheet once fed from the roll (that is, the control for rewinding to the original roll) must be performed. Therefore, highly accurate alignment cannot be performed. Therefore, as shown in FIG. 2B, there may be a case where the land 530 and the via 520 are misaligned along the MD direction. FIG. 2B is an enlarged view of the area 96 in FIG. Thus, when the positional deviation between the via and the land occurs along the MD direction, it is very difficult to correct the positional deviation between the two and time is also consumed.

  Further, the positional deviation in the MD direction between the land and the via can also occur when the sheet base material is deformed during the heating process. That is, since the sheet base material of the flexible substrate is a very thin film, the dimensional stability cannot be expected so much. In addition, the roll-to-roll method does not cause wrinkles or slack, so that the traveling direction of the sheet base material (so-called MD) The sheet base material is thermally contracted in the MD direction through the heating process. Due to the thermal contraction of the base material, the distance between the vias is also smaller than the design in the MD direction, and positional deviation may occur between the land and the via.

  When the alignment between the land and the via of the wiring pattern is not successful and the positional deviation between the land and the via occurs, the conduction between the front and back of the flexible substrate cannot be ensured, and there is a possibility that many poor connections occur.

  The present invention has been made in view of such a point, and a main object thereof is to provide a flexible substrate capable of reliably connecting a land and a via of a wiring pattern.

  The flexible substrate of the present invention includes a flexible substrate, vias that electrically connect the upper surface and the lower surface of the substrate, and lands formed on the vias, The length of the base material in the vertical direction is longer than the length of the base material in the horizontal direction.

  In a preferred embodiment, a resin layer is formed on an upper surface and a lower surface of the base material, and each of the lands is embedded in the resin layer.

  In a preferred embodiment, the via connected to each land is a paste via formed by filling a conductive paste.

  In a preferred embodiment, the longitudinal direction of the base material is an MD direction that is a traveling direction of the base material in a roll-to-roll manufacturing method.

  In a preferred embodiment, the longitudinal direction of the substrate is a direction in which the amount of thermal shrinkage of the substrate is larger than the lateral direction of the substrate.

  In a preferred embodiment, the shape of the land is a rectangle, an ellipse, or an ellipse whose longitudinal direction is along the longitudinal direction of the substrate.

  The multilayer flexible substrate of the present invention is a multilayer flexible substrate in which a plurality of flexible substrates are laminated, and the upper surface and the lower surface of at least one of the plurality of laminated substrates are electrically connected. Vias connected to each other and lands formed on the vias, each land having a shape in which the longitudinal length of the base material is longer than the lateral length of the base material. is doing.

  In a preferred embodiment, the via connected to each land is filled with a conductive paste.

  In a preferred embodiment, the base material is laminated in three or more layers, and among the base materials laminated in the three or more layers, the base materials arranged on the upper surface and the lower surface of the multilayer flexible substrate include: A plated via is formed.

  The method for producing a flexible substrate of the present invention is a method for producing a flexible substrate by a roll-to-roll method, and prepares a carrier sheet in which a land pattern having a longitudinal shape is arranged along the traveling direction of the carrier sheet. Each of the step (a), the step (b) of arranging the land pattern having the shape in the longitudinal direction so as to face the substrate sheet on which the via is formed, and the land pattern having the shape in the longitudinal direction are arranged. And a step (c) of aligning and pressing the via on the base sheet.

  In a preferred embodiment, in the step (c), the pressing is performed while being sandwiched between a pair of rollers.

  The method for producing a multilayer flexible substrate of the present invention is a method for producing a multilayer flexible substrate by a roll-to-roll method, wherein a land pattern having a longitudinal shape is formed along the traveling direction of the first base sheet. Preparing the first base sheet and arranging the land pattern having the shape in the longitudinal direction of the first substrate sheet so as to face the second base sheet on which the via is formed. And a step of aligning and pressing each of the land patterns having the shape in the longitudinal direction to the vias of the second base sheet.

  In a preferred embodiment, the via formed in the second base sheet is a paste via filled with a conductive paste.

  In a preferred embodiment, among the land patterns formed on the first base sheet, all land patterns connected to the paste vias are longitudinal along the traveling direction of the first base sheet. It has the shape of

  The flexible substrate of the present invention includes a base material having flexibility, vias that electrically connect the upper surface and the lower surface of the base material, and lands formed on the vias. Since the length of the base material in the vertical direction is longer than the length in the horizontal direction, when manufacturing by the roll-to-roll method, vias and land patterns in the MD direction are highly accurate. Even without alignment, a sufficient electrical connection between the via and the land pattern can be ensured. Therefore, a flexible substrate that can be easily manufactured can be provided, and the manufacturing time can be shortened. In addition, by forming the land pattern in the longitudinal direction along the MD direction, the land pattern is formed into a land pattern shape capable of following the dimensional change in the MD direction due to thermal shrinkage during the etching process or the hot press process. Therefore, connection failure between the via and the land pattern can be surely suppressed. As a result, via connection reliability can be improved.

  Embodiments according to the present invention will be described below with reference to the drawings. In the following drawings, members / parts having the same action are described with the same reference numerals. In addition, this invention is not limited to the following embodiment.

  First, the configuration of the flexible substrate 100 according to the embodiment of the present invention will be described with reference to FIGS. 3 (a) and 3 (b). 3A is a top view schematically showing the top surface configuration of the flexible substrate 100, and FIG. 3B is a cross-sectional view schematically showing the AA cross section in FIG. 3A. .

  The flexible substrate 100 of this embodiment is a double-sided flexible substrate in which wiring patterns are formed on the upper surface 16 and the lower surface 18 of the base material 10, respectively. The flexible substrate 100 includes a base material 10, vias 20, and lands 30.

  The base material 10 is made of a flexible resin material, and is, for example, a resin film such as an aramid film or a polyimide film. In this embodiment, an aramid film is used as the substrate 10. Moreover, the resin layer 14 is laminated | stacked on the upper surface 16 and the lower surface 18 of the base material 10 of this embodiment, respectively. The resin layer 14 has adhesiveness and is typically formed by applying an adhesive. The resin layer 14 has a function of accommodating the wiring patterns 32 formed on both surfaces (the upper surface 16 and the lower surface 18) of the base material 10. In the present embodiment, the base material 10 has a thickness of 4 μm, and the resin layer 14 has a thickness of 10 μm.

  The via 20 is an interlayer connection member that electrically connects the upper surface 16 and the lower surface 18 of the substrate 10. The via 20 of the present embodiment is formed by filling a circular hole formed by laser processing with a conductive paste by a printing method (so-called paste via). The conductive paste is made of a resin having electrical conductivity. For example, a resin containing metal powder (for example, silver powder) or carbon powder as conductive particles can be used.

  The land 30 is formed on the via 20. In the illustrated example, a pair of lands 30 a and lands 30 b are formed above and below the via 20, respectively. The land 30 of the present embodiment is made of a metal foil (for example, copper foil), and has a substantially elliptical shape here. The land 30 is formed by being embedded in the resin layer 14 by a transfer method. The land 30 of the present embodiment is thinner than the resin layer, for example, 9 μm.

  Each land 30 formed on the via 20 has a shape in which the longitudinal length (L1) of the substrate 10 is longer than the lateral length (L2) of the substrate 10. (Ie L1> L2). In the present embodiment, all the lands 30 connected to the via 20 have a uniformly long shape along the vertical direction. Here, the six lands 30 connected to the paste via 20 have an elliptical shape that is long in one direction. In the illustrated example, the length (L1) in the vertical direction of the land 30 is 200 μm, and the length (L2) in the horizontal direction of the land 30 is 150 μm. Further, the diameter dimension (R) of the circular via 20 is set to be smaller than the lateral length (L2) of the land 30 in order to ensure the connection with the land 30. The diameter (R) of the via 20 of the embodiment is 50 μm. Thus, in the present embodiment, the dimensions (R, L1, L2) of the via 20 and the land 30 are configured to satisfy L1> L2> R.

  As shown in FIG. 4, the “longitudinal direction” of the base material here is an MD direction (Machine Direction) which is a traveling direction of the base material 10 when the flexible substrate 100 is manufactured using the roll-to-roll method. That is. Further, the “lateral direction” of the base material 10 is a TD direction (Transverse Direction) which is the width direction of the base material 10 in a roll state. That is, in this embodiment, the land 30 connected to the via 20 has a shape in which the length of the base material 10 in the MD direction is longer than the length of the base material 10 in the TD direction.

  The difficulty of alignment control by the roll-to-roll method differs greatly between the MD direction and the TD direction of the substrate 10. That is, the MD direction of the base material 10 is a direction in which fine adjustment of alignment is difficult compared to the TD direction. This is because, in the roll-to-roll system, when the alignment in the MD direction is performed, it is necessary to perform control for returning each sheet once sent from the roll, that is, control for rewinding to the original roll.

  According to the configuration of this embodiment, since the shape of the land 30 is long along the MD direction where alignment is difficult, alignment of the via 20 and the land 30 in the MD direction is facilitated, and therefore Continuous mass production is possible by applying the roll-to-roll method. This will be described below with reference to FIG.

  5A to 5E are cross-sectional process diagrams schematically showing the manufacturing process of the flexible substrate 100 according to this embodiment. As described above, the flexible substrate 100 is manufactured by the roll-to-roll method, and each material sheet supplied from the roll state is sequentially conveyed in the direction of the arrow 93 (MD direction) in the figure, and sequentially illustrated in FIG. Steps a) to (e) are executed.

  First, as shown in FIG. 5A, a carrier sheet 40 on which land patterns 30 are arranged is prepared. The land pattern 30 on the carrier sheet 40 has a shape in the longitudinal direction along the MD direction (the direction of the arrow 93 in which the carrier sheet 40 supplied from the state wound in a roll shape proceeds). That is, the shape of the land pattern 30 is longer in the MD direction length (L1) than in the TD direction length (L2). In the present embodiment, a release material 41 is applied on the carrier sheet 40 to facilitate the transfer of the land pattern 30. Moreover, in order to manufacture the double-sided flexible substrate 100, two carrier sheets 40 are prepared for the upper surface and the lower surface of the substrate.

  Next, as shown in FIG. 5B, the land pattern 30 on the carrier sheet 40 is disposed so as to face the base sheet 10 on which the vias 20 are formed. A paste via 20 filled with a conductive paste is formed on the base sheet 10 of the present embodiment. Moreover, the resin layer 14 for embedding the land pattern 30 is formed on both surfaces of the base material sheet. In addition, when the thickness dimension of the base material sheet 10 and the resin layer 14 is illustrated, the thickness of the base material sheet 10 is 4 micrometers, and the thickness of the resin layer 14 is 10 micrometers. At this time, the thickness of the land pattern 30 is, for example, 9 μm.

  Subsequently, alignment is performed so that each of the land patterns 30 having a shape long in the MD direction is opposed to the via 20 of the base sheet 10. This alignment is performed in the XY direction of the base material sheet 10, that is, in the MD direction and the TD direction of the base material 10, respectively. At this time, since the land 30 has a long shape along the MD direction, the alignment in the MD direction represented by the arrow 95 becomes easy, and it is not necessary to perform control to rewind the base sheet 10 onto the roll.

  When this alignment is completed, as shown in FIG. 5C, the land pattern 30 is embedded in the resin layer 14 of the base sheet 10 by the pressure by the hot press indicated by the arrow 97, and the land pattern 30 and the via 20 are Connect. In the present embodiment, the hot pressing is performed using a flat plate.

  Thereafter, as shown in FIG. 5D, when the carrier sheet 40 is peeled off, as shown in FIG. 5E, the flexible substrate 100 in which the land pattern 30 having the shape in the longitudinal direction and the via 20 are connected is obtained. Complete.

  In the method for manufacturing the flexible substrate 100 of the present embodiment, the land pattern 30 connected to the via 20 has a shape in the longitudinal direction along the MD direction, so that the height of the via 20 and the land pattern 30 in the MD direction is high. Even if accurate alignment is not performed, the electrical connection between the via 20 and the land pattern 30 can be sufficiently ensured. Therefore, the flexible substrate 100 that can be easily manufactured can be provided, and the manufacturing time can be shortened.

  In the transfer using a typical roll-to-roll system, the alignment of the land pattern 30 and the paste via 20 in the MD direction becomes a bottleneck, and continuous production, which is an advantage of the roll-to-roll system, cannot be realized. That is, when performing alignment in the MD direction, control to rewind to the original roll has to be performed, and fine adjustment of alignment has been difficult. On the other hand, in this embodiment, by aligning a land pattern and a via that are long in the MD direction, which is difficult to align, the land and the via can be reliably connected without performing high-precision alignment. Therefore, continuous production by a roll-to-roll system is possible. This also facilitates work automation and improves yield.

  In the TD direction, which is easy to align even in the roll-to-roll system, land formation with a narrow pitch in the TD direction is realized by making the land length dimension (L2) smaller than the length (L1) in the MD direction. Can do. That is, in the flexible substrate 100 of the present embodiment, it is not necessary to perform high-precision alignment in the MD direction where alignment is difficult while achieving narrow pitch land formation in the TD direction where alignment is easy, Therefore, the flexible substrate 100 having a narrow pitch and easy to manufacture can be provided.

  In addition, since the land pattern 30 can be formed in the shape of the longitudinal direction along the direction in which the thermal contraction amount of the base sheet 10 is large (that is, the MD direction), the MD direction caused by the thermal contraction during the heating process. The land 30 can be formed in a shape capable of following the dimensional change. Since the base material 10 of the flexible substrate 100 is made of a very thin resin film, the base material sheet 10 may be thermally contracted during heating. However, in the above configuration, due to dimensional change during the heating process (thermal contraction in the MD direction). Since it can be formed in a corresponding shape, even if thermal shrinkage occurs, the positional deviation between the via 20 and the land 30 can be sufficiently suppressed. As a result, the connection reliability of the via 20 can be improved.

  Next, referring to FIG. 6A, an example of a specification capable of realizing the above configuration will be described. The diameter (R) of the paste via 20 of this embodiment is set to 50 μm, and at this time, the TD of the land 30 is set. The length (L2) in the direction is larger than the diameter (R) of the via 20, for example, 100 μm or more, and preferably 150 μm. The MD length (L1) of the land 30 is larger than the lateral dimension (L2) of the land 30 and is set to, for example, 150 μm or more, and more preferably 200 μm. In addition, the length of each direction of the land 30 described above can be appropriately set to an appropriate size according to the diameter of the via 20 and various conditions during manufacturing.

  In the present embodiment, the land pattern 30 is shown as an example having an elliptical shape 50a that is long in the MD direction shown in FIG. 6A. However, the land shape is not limited to the elliptical shape 50a, and may be other shapes. Also good. For example, as shown in FIGS. 6B to 6D, (b) a rhombus 50b, (b) an ellipse 50c, or (c) where the longitudinal direction of the land is along the longitudinal direction (MD direction) of the substrate. ) It can be formed in the shape of a rectangle 50d. When the land shape is the rhombus 50b, land patterns can be formed at a narrow pitch while ensuring the connection with vias in the MD direction. Further, when the land shape is an ellipse 50c, an allowable range including a positional deviation in the TD direction can be ensured even when using a material that causes a certain dimensional shrinkage in the TD direction. Even in such a material, there is an advantage that the roll-to-roll method can be used.

  Further, in the present embodiment, as shown in FIG. 3, all the lands 30 have a configuration extending in one direction (MD direction). However, the present invention is not limited to this. Such lands 30 are arranged in a region where a wiring pattern is required, and a region where no land is formed outside the predetermined region, or a shape that does not extend in the MD direction (for example, It is also possible to arrange lands having a circular shape. In addition, the shapes of the lands 30 extending in the MD direction do not have to be the same. If the lands 30 extend in the MD direction, they have the shapes shown in FIGS. Can also be mixed.

  Below, the manufacturing method of the flexible substrate 100 of this embodiment is further demonstrated in detail. As described above, the flexible substrate 100 of this embodiment can be continuously executed by a roll-to-roll method. That is, the carrier sheet 40 and the base sheet 10 can be continuously supplied from the state of being wound in a roll shape. The transfer by the roll-to-roll method can be executed, for example, as shown in FIG.

  First, the base material sheet 10 on which the paste via 20 is formed is sent out in the direction of the arrow 90 (MD direction) by the rotation 92 of the roll 60 and conveyed to a position below the flat plate 62. On the other hand, the carrier sheet 40 on which the land pattern 30 having a longitudinal shape is arranged along the MD direction is sent out from the roll 64 by the rotation 94 of the roll 64 and conveyed to a position below the flat plate 62 flat plate 62. Next, alignment is performed so that the paste via 20 of the base sheet 10 and the land pattern 30 having a shape in the longitudinal direction face each other, and transfer is performed by hot pressing of the flat plate 62. After the land pattern 30 is transferred to the resin layer 14 laminated on both surfaces of the base sheet 10 by hot pressing of the flat plate 62, the carrier sheet 40 is wound up by a roll 66. The transferred base material sheet 10 (flexible substrate 100) on which the land pattern 30 has been formed is again wound into a roll by the roll 68 and delivered to the next process (for example, a cutting process). In this way, since the long land and the paste via are aligned along the MD direction, high alignment accuracy is not required in the MD direction, and the roll-to-roll method is used for continuous production. It becomes possible.

  In the example shown in FIG. 7, the transfer of the land pattern is performed by intermittently transporting each sheet to the position of the flat plate 62, and is performed by hot pressing of the flat plate 62, but the transfer of the land pattern is performed by the flat plate 62. For example, as shown in FIG. 8, hot pressing may be performed using a pair of rolls 63. In this case, the base sheet 10 may be passed between a pair of rolls (nip rolls) 63, and the land pattern may be transferred to the resin layer there. With this configuration, it is possible to achieve more continuous production compared to the intermittent conveyance process in which each sheet is conveyed intermittently and the pressing process and the like are performed individually.

  The merit of making the land connected to the via long in the MD direction can be obtained not only when transferring the land pattern of the double-sided flexible substrate described above, but also when constructing a multilayer flexible substrate. A multilayer flexible substrate can be constructed by laminating a plurality of flexible substrates.

  For example, FIGS. 9A and 9B show a manufacturing process of the multilayer flexible substrate 200 in which three base sheets (210, 212a, 212b) are laminated. The multilayer flexible substrate 200 is formed by laminating a base sheet (first base sheet) 212 having lands formed on both sides and a base sheet (second base sheet) 210 having paste vias formed thereon. Is built by

  First, as shown in FIG. 9A, a base sheet 212 provided with lands 230 having a longitudinal shape along the MD direction (advancing direction of the base sheet 212) is prepared. In the present embodiment, the base sheet 212 is a plated substrate provided with lands on both sides. The land 230 having a shape in the longitudinal direction is provided on one surface of the base sheet 212, and a circular land 234 is formed on the opposite surface. Here, two sheets of the base sheet 212 are prepared on the upper surface side and the lower surface side of the multilayer flexible substrate.

  Next, as illustrated in FIG. 9B, the land 230 having a shape in the longitudinal direction is disposed so as to face the base sheet 210. Paste vias 220 are formed on the base sheet 210, and resin layers 214 are provided on both sides of the base sheet 210. Next, alignment is performed so that each of the lands 230 having the shape in the longitudinal direction faces the paste via 220 of the base sheet 210. At this time, since each land to be connected to the paste via has a uniformly long shape along the MD direction, alignment can be easily performed even when the land is embedded in the resin layer.

  Thereafter, as shown in FIG. 9C, the land 230 having a shape in the longitudinal direction is embedded in the resin layer 14 of the base sheet 210 by pressure by hot pressing, and the land 230 and the paste via 220 are connected. Then, the multilayer flexible substrate 200 is completed by cutting into predetermined dimensions.

  As described above, even when the multilayer flexible substrate 200 is constructed by laminating a plurality of base materials, the long land 230 and the paste via 220 are positioned along the MD direction as in the land transfer of the double-sided flexible substrate 100. Therefore, high alignment accuracy is not required in the MD direction. That is, the multilayer flexible substrate 200 that can be easily manufactured can be provided. Thereby, continuous production is also possible by applying the roll-to-roll method. In addition, since the land 230 on the paste via 220 can be formed in a shape corresponding to the thermal contraction of the base material during the heating process, the positional deviation between the paste via 220 and the land 230 can be suppressed.

  In the production of a conventional multilayer flexible substrate, the alignment in the MD direction becomes a bottleneck and cannot be continuously produced by the roll-to-roll method, and it is very troublesome to stack the substrates one by one in a multilayer. Moreover, since it is necessary to handle thin substrates one by one carefully, there has been a limit to reducing the thickness of the multilayer substrate. On the other hand, in the above manufacturing method, since it is possible to continuously manufacture by a roll-to-roll method, it becomes easy to automate the manufacturing line, and it is possible to manufacture a thinner multilayer flexible substrate by improving the handling property. It becomes.

  In addition, if each land to be connected to the paste via has a uniformly long shape along the MD direction, the alignment between the paste via and the land can be easily performed, Therefore, lands connected to vias other than paste vias do not have to be uniformly long. For example, since the land connected to the plating via is directly formed on the plating via 222 by the etching process, the land may not be long in one direction (for example, a circular shape).

  An example of the multilayer flexible substrate 200 constructed in this way is as shown in FIG. FIG. 10A is a top view schematically showing a top surface configuration of the multilayer flexible substrate 200, and FIG. 10B is a cross-sectional view schematically showing a BB cross section in FIG. is there.

  In this example, the multilayer flexible substrate 200 is formed by laminating three base materials (210, 212a, 212b), and two base materials 212 (212a) provided on the uppermost surface and the lowermost surface (that is, the surface layer) of the substrate 200. 212b) and one substrate 210 provided in the center (ie, the inner layer) of the substrate 212 of the surface layer.

  The substrate 210 located in the inner layer is provided with a paste via 220, and the land 230 connected to the paste via 220 has an elliptical shape that is long in the MD direction. Thereby, alignment with the paste via | veer 220 and the land 230 can be performed easily.

  On the other hand, the surface base materials 212a and 212b are provided with plated vias, and the lands 234 connected to the plated vias 222 have a substantially circular shape (that is, a shape in which the length in the MD direction is substantially equal to the length in the TD direction). Yes. This plated via can be formed as follows. First, a hole (through hole) is formed at a predetermined position of the base material 212 by laser processing or the like, and then a metal foil is laminated on the base material 212 (for example, copper plating). Thereby, the plated via 222 is formed. Then, when the laminated metal foil is selectively etched, a circular land 234 can be formed.

  Thus, in the case of a multilayer flexible substrate, the lands on all vias formed in the substrate do not have to be uniformly long, and at least in one base material on which paste vias are formed, It is only necessary that the land connected to the paste via has a uniformly long shape.

  In addition, as shown here, it is possible to form a narrow pitch wiring pattern on the surface layer of the multilayer flexible substrate by configuring the base material 212 of the surface layer of the multilayer flexible substrate from a plated substrate.

  9 and 10 show an example of the multilayer flexible substrate 200 in which three base materials are laminated. However, the present invention is not limited to this, and it is also possible to construct a multilayered multilayer flexible substrate. In this case, the multilayer flexible substrate 200 obtained in FIG. 9 may be further multilayered, or all the base materials constituting the multilayer flexible substrate may be laminated simultaneously to realize multilayering. You can also.

  FIG. 11 shows a configuration of a multilayer flexible substrate 300 according to another embodiment. The multilayer flexible substrate 300 is different from the multilayer flexible substrate 200 described above in that a paste via 320 is provided on the base layer 310 on the surface layer side and a plating via 322 is formed on the base layer 312 on the inner layer side. Even in such a configuration, the lands 330 (330a and 330b) connected to the paste via 320 can be formed in a shape that is long in the MD direction, thereby aligning the paste via 320 and the land 330 during manufacturing. Can be easily. This will be described with reference to FIG.

  First, as shown in FIG. 12A, a base sheet (first base sheet) 312 provided with lands 330b having a longitudinal shape along the MD direction (traveling direction of the base sheet 312). Prepare. The base sheet 312 is a plated substrate, and lands 334 connected to the plated vias 322 are formed in addition to the lands 330b having a shape in the longitudinal direction. Since the land 334 is connected to the plated via, the land 334 may not have a uniform long shape.

  Next, as illustrated in FIG. 12B, the land 330 b having a shape in the longitudinal direction is disposed so as to face the paste via 320 of the base sheet (second base sheet) 310. In this embodiment, the two base material sheets 310 are respectively disposed above and below the base material sheet 312. Resin layers 314 are provided on both surfaces of the substrate sheet 310, and lands 330a are embedded in advance in the resin layer 314a on the surface side that is not opposed to the substrate sheet 312 (that is, the surface layer side) by transfer. The land 330a is formed in a shape long in the MD direction so as to be connected to the paste via 320. Next, each land 330 b having a shape in the longitudinal direction is aligned with the paste via 320 of the base sheet 310.

  Thereafter, as shown in FIG. 12C, the land 330 b is embedded in the resin layer 314 b of the base sheet 310 by pressure by hot pressing, and the land 330 b and the paste via 320 are connected. In this way, the multilayer flexible substrate 300 is completed.

  Even in the above manufacturing method, the long land and the paste via are aligned along the MD direction, so that a high alignment accuracy is not required in the MD direction. It becomes easy and continuous production is also possible by applying a roll-to-roll method.

  The land shape long in the MD direction described above is not limited to the connection with the via, but can be used for mounting an electronic component (for example, a semiconductor chip), for example. In the example shown in FIG. 13, the semiconductor chip 450 is connected to the lands 430 of the wiring pattern 432 formed on the upper surface of the flexible substrate 400 via connection members (for example, bumps and solder). The land 430 connected to the semiconductor chip 450 has a long elliptical shape along the MD direction. Thereby, even if the base material (and the wiring pattern) is deformed (thermally contracted) in the MD direction through a heating process or the like, the semiconductor chip 450 can be reliably mounted.

  Here, the wiring pattern 432 connected to the semiconductor chip 450 is formed so as to be substantially parallel to the MD direction, and the semiconductor chip 450 is mounted on the land 430 at the tip of the wiring pattern 432 extending in the MD direction. ing. With this configuration, the deformation (thermal contraction) of the base material (and the wiring pattern) in the MD direction can be easily followed, so that the semiconductor chip 450 can be reliably mounted. In addition, since the land 430 can be formed small in the TD direction, a wiring pattern with a very narrow pitch can be formed, and high-density mounting can be realized.

  As mentioned above, although this invention was demonstrated by suitable embodiment, such description is not a limitation matter and of course various modifications are possible.

  ADVANTAGE OF THE INVENTION According to this invention, the flexible substrate which can connect the land and via | veer of a wiring pattern reliably can be provided.

(A)-(c) Process sectional drawing explaining the method of forming a wiring pattern by transcription | transfer (A) is a figure for demonstrating transcription | transfer of the wiring pattern by a roll-to-roll system, (b) is a figure which shows an example when a land and a via have shifted position (A) is a top view schematically showing the top surface configuration of the flexible substrate 100, and (b) is a cross-sectional view schematically showing the AA cross section in (a). The figure for demonstrating MD direction and TD direction in a roll-to-roll system Cross-sectional process drawing schematically showing the manufacturing process of the flexible substrate 100 according to the present embodiment Diagram for explaining land pattern shape The figure for demonstrating transfer of the wiring pattern by the roll-to-roll system which concerns on this embodiment The figure for demonstrating the transcription | transfer of the wiring pattern by the roll-to-roll system which concerns on this embodiment (A)-(c) is process sectional drawing which showed the manufacturing process of the multilayer flexible substrate 200 typically. (A) is a top view schematically showing the top surface configuration of the multilayer flexible substrate 200, and (b) is a sectional view schematically showing the BB cross section in (a). Sectional drawing which shows typically the structure of the multilayer flexible substrate 300 which concerns on another embodiment. (A)-(c) is process sectional drawing which showed the manufacturing process of the multilayer flexible substrate 300 typically. Diagram for explaining mounting of electronic components on flexible board

Explanation of symbols

10 Base material (base material sheet)
14 resin layer 16 upper surface 18 lower surface 20 via 30 land 32 wiring pattern 40 carrier sheet 41 release material 60 roll 62 flat plate 63 roll 64 roll 66 roll 68 roll 100 flexible substrate 200 multilayer flexible substrate 210 substrate (second substrate sheet)
212 base material (first base material sheet)
214 Resin layer 220 Paste via 222 Plating via 230 Land 234 Land 300 Multilayer flexible substrate 310 Base material (second base material sheet)
312 Base material (first base material sheet)
314 Resin layer 320 Paste via 322 Plating via 330 Land 334 Land 400 Flexible substrate 430 Land 432 Wiring pattern 450 Semiconductor chip 510 Sheet substrate 514 Resin layer 520 Via 530 Land 532 Wiring pattern 540 Carrier sheet

Claims (14)

  1. A flexible substrate;
    Vias electrically connecting the upper and lower surfaces of the substrate;
    A land formed on the via,
    Each land has a shape in which the length in the vertical direction of the base material is longer than the length in the horizontal direction of the base material.
  2. A resin layer is formed on the upper and lower surfaces of the base material,
    The flexible substrate according to claim 1, wherein each land is embedded in the resin layer.
  3. The flexible substrate according to claim 1, wherein the via connected to each land is a paste via formed by being filled with a conductive paste.
  4. The flexible substrate according to any one of claims 1 to 3, wherein a longitudinal direction of the base material is an MD direction that is a traveling direction of the base material in a roll-to-roll manufacturing method.
  5. The flexible substrate according to any one of claims 1 to 3, wherein a longitudinal direction of the base material is a direction in which a heat shrinkage amount of the base material is larger than a lateral direction of the base material.
  6. The flexible substrate according to any one of claims 1 to 5, wherein a shape of the land is a rectangle, an ellipse, or an ellipse whose longitudinal direction is along the longitudinal direction of the base material.
  7. A multilayer flexible substrate in which a plurality of flexible base materials are laminated,
    Vias for electrically connecting the upper and lower surfaces of at least one of the plurality of stacked substrates; and
    A land formed on the via,
    Each land has a shape in which the length in the vertical direction of the base material is longer than the length in the horizontal direction of the base material.
  8. The multilayer flexible substrate according to claim 7, wherein the via connected to each land is filled with a conductive paste.
  9. The base material is laminated with three or more layers,
    The multilayer flexible substrate according to claim 7 or 8, wherein a plating via is formed on a substrate disposed on an upper surface and a lower surface of the multilayer flexible substrate among the substrates laminated in three or more layers.
  10. A method of manufacturing a flexible substrate by a roll-to-roll method,
    A step (a) of preparing a carrier sheet in which a land pattern having a shape in a longitudinal direction is arranged along the traveling direction of the carrier sheet;
    Arranging the land pattern having the shape in the longitudinal direction so as to face the base sheet on which the via is formed; and
    And a step (c) of aligning and pressing each of the land patterns having the shape in the longitudinal direction with the vias of the base sheet.
  11. The method for manufacturing a flexible substrate according to claim 10, wherein in the step (c), pressing is performed while being sandwiched between a pair of rollers.
  12. A method for producing a multilayer flexible substrate by a roll-to-roll method,
    Preparing a first base sheet on which a land pattern having a shape in the longitudinal direction is formed along the traveling direction of the first base sheet;
    Arranging the land pattern having the shape in the longitudinal direction of the first substrate sheet so as to face the second substrate sheet on which vias are formed;
    And a step of aligning and pressing each of the land patterns having the shape in the longitudinal direction with the vias of the second base sheet.
  13. The method for manufacturing a multilayer flexible substrate according to claim 12, wherein the via formed in the second base sheet is a paste via filled with a conductive paste.
  14. Of the land patterns formed on the first base sheet, all the land patterns connected to the paste vias have a longitudinal shape along the traveling direction of the first base sheet. A method for producing a multilayer flexible substrate according to claim 13.
JP2006331532A 2006-12-08 2006-12-08 Flexible board, and its manufacturing method Pending JP2008147328A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011129127A1 (en) * 2010-04-15 2011-10-20 日本メクトロン株式会社 Multi-layer flexible printed circuit board and method of manufacturing thereof
JP2013191647A (en) * 2012-03-13 2013-09-26 Dainippon Printing Co Ltd Current collection sheet for solar battery
CN109792838A (en) * 2016-09-23 2019-05-21 斯天克有限公司 The flexible printed circuit board for having via pad
US10403650B2 (en) 2017-05-19 2019-09-03 Gio Optoelectronics Corp. Electronic device and manufacturing method thereof

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011129127A1 (en) * 2010-04-15 2011-10-20 日本メクトロン株式会社 Multi-layer flexible printed circuit board and method of manufacturing thereof
JP2011228348A (en) * 2010-04-15 2011-11-10 Nippon Mektron Ltd Multilayer flexible printed wiring board and manufacturing method thereof
CN102396300A (en) * 2010-04-15 2012-03-28 日本梅克特隆株式会社 Multi-layer flexible printed circuit board and method of manufacturing thereof
TWI484884B (en) * 2010-04-15 2015-05-11 Nippon Mektron Kk Multi-layer flexible printed wiring board and manufacturing method thereof
JP2013191647A (en) * 2012-03-13 2013-09-26 Dainippon Printing Co Ltd Current collection sheet for solar battery
CN109792838A (en) * 2016-09-23 2019-05-21 斯天克有限公司 The flexible printed circuit board for having via pad
US10403650B2 (en) 2017-05-19 2019-09-03 Gio Optoelectronics Corp. Electronic device and manufacturing method thereof

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