JP2014192259A - Double-sided wiring flexible substrate and inspection method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a double-sided wiring flexible substrate having a structure which prevents erroneous detection from occurring in the transmission type image inspection if positional deviation is within an allowable range even when the positional deviation occurs on both surfaces of lands, and also to provide an inspection method of the double-sided wiring flexible substrate.SOLUTION: A double-sided wiring flexible substrate includes: an insulating base material 10 made of an insulation film; a through-hole 50 which penetrates through the insulating base material; first and second lands 40 and 70 formed on both surfaces of the insulating base material so as to contain through-holes; and first and second wiring patterns 30 and 80 connected to the first and second lands, respectively. The first land is larger than the second land and encompasses the second land in a top view.

Description

  The present invention relates to a double-sided wiring flexible substrate and an inspection method thereof.

  Conventionally, a flexible wiring substrate has been used as a substrate for mounting an IC (Integrated Circuit) chip for driving a display such as liquid crystal or EL (Electro Luminescence).

  As the demand for higher definition of displays increases, the flexible wiring board used therefor is also required to have higher functionality and higher density. In order to meet such demands, flexible wiring boards (double-sided wiring flexible boards) in which wiring is formed on both surfaces of various insulating base materials have been developed (for example, see Patent Documents 1 and 2).

  For example, in Patent Document 1, a through-hole is provided in a base substrate made of polyimide, polyester, or the like, a plated layer is formed in the through-hole portion, and a driving IC is connected to a driving IC chip mounting surface of the base substrate. There is described a flexible wiring board in which an inner lead portion to be formed is formed and an outer lead portion connected to a liquid crystal display panel is formed on a surface where the driving IC chip is not mounted.

  Further, in Patent Document 2, copper foil is provided on both sides of an insulating base made of an insulating film, and a predetermined number of through holes are formed in the insulating base so as to penetrate predetermined positions on both sides. A double-sided wiring film carrier is described in which a wiring pattern is formed by etching and then a cover lay is attached to one surface for wiring protection and then a solder resist is applied to the other surface.

  In these double-sided wiring flexible boards, the base material is film-like and light is transmitted. Therefore, after the double-sided wiring flexible board is completed, light is applied from one side of the board and the transmission image is detected. In addition, a transparent appearance inspection is performed to detect abnormalities such as chipping or weighting of wiring.

JP 2003-197676 A JP-A-2005-236131

  However, in the conventional double-sided wiring flexible board, the shape and size of the land part where the through hole is formed are formed equally on both sides, and the positional deviation amount is within the reference range when the land part on both sides is misaligned. Even within this, there was a problem that the misalignment of the land portion was erroneously detected as missing wiring.

  FIG. 1 is a view showing a configuration including a land portion of a conventional double-sided wiring flexible substrate. FIG. 1A is a cross-sectional view of a conventional double-sided wiring flexible substrate. In FIG. 1A, a through hole 250 is formed in the insulating base 210, a plating layer 260 is formed in the through hole 250, and land portions 240, so as to close the upper and lower openings of the through hole 250, 270 is formed. Here, the land portion 240 on the upper surface and the land portion 270 on the lower surface have the same shape and size.

  FIG. 1B is a top view of a conventional double-sided wiring flexible substrate. As shown in FIG. 1B, the land portion 240 is formed so as to contain the plating layer 260, and the wiring pattern 230 is connected thereto. Further, since the land portion 270 opposite to the land portion 240 and below the land portion 240 has the same shape and size as the land portion 240, the land portion 240 and the land portion 270 are viewed from above. Overlapping, the land portion 270 is hidden by the land portion 240. In addition, a wiring pattern 280 is connected to the land portion 270.

  FIG. 2 is a view showing a light transmission image when a conventional double-sided wiring flexible board is inspected by a transmission type visual inspection apparatus. FIG. 2A is a diagram showing a state where light is applied from one side of the double-sided wiring flexible board and a light transmission image is taken from the opposite side. As shown in FIG. 2A, since the insulating base 210 without wiring is transparent to light, the light transmission image forms a white image, and the wiring pattern 230, 280 that does not transmit light is A black image is formed. If the land portion 240 on the upper surface and the land portion 270 on the lower surface coincide and overlap, as shown in FIG. 2A, the land portion 240 appears as one.

  On the other hand, FIG. 2B is a diagram showing a light transmission image in the case where a positional shift occurs in the land portions on both sides. In the conventional double-sided wiring flexible board, since the land portions 240 and 270 in which the through holes 250 are formed have the same shape and size, if the land portions 240 and 270 on both sides are misaligned, a transparent appearance A transmission image of the inspection is detected as shown in FIG. When such a transmission image is detected, even if the amount of misalignment is actually within the allowable range, misalignment of the land portions 240 and 270 is erroneously detected as missing wiring, resulting in a decrease in yield. There was a problem that.

  Therefore, the present invention provides a double-sided wiring flexible board having a structure that does not cause false detection in a transmission image inspection and a method for inspecting the same when the positional deviation is within an allowable range even when positional deviation occurs in both land portions. The purpose is to provide.

In order to achieve the above object, a double-sided wiring flexible substrate according to an aspect of the present invention includes an insulating base material made of an insulating film,
A through hole penetrating the insulating substrate;
First and second land portions formed on both surfaces of the insulating base so as to include the through holes;
First and second wiring patterns connected to each of the first and second land portions;
The first land portion is larger than the second land portion and includes the second land portion in a top view.

Moreover, the inspection method of the double-sided wiring flexible board according to another aspect of the present invention includes a step of placing the double-sided wiring flexible board such that the first land portion is an upper surface,
A step of performing a transmission visual inspection from the upper surface of the first land portion and the second land portion.

  According to the present invention, in the transmission type projection image inspection, it is possible to prevent erroneous detection of a wiring defect or the like due to a land portion misalignment.

It is the figure which showed the structure containing the land part of the conventional double-sided wiring flexible substrate. FIG. 1A is a cross-sectional view of a conventional double-sided wiring flexible substrate. FIG. 1B is a top view of a conventional double-sided wiring flexible substrate. It is the figure which showed the light transmissive image at the time of test | inspecting the conventional double-sided wiring flexible substrate with a transmissive | pervious external appearance inspection apparatus. FIG. 2A is a diagram showing a state where light is applied from one side of the double-sided wiring flexible board and a light transmission image is taken from the opposite side. FIG. 2B is a diagram showing a light transmission image in a case where the positional deviation occurs in the land portions on both sides. It is the top view which showed the whole structure of an example of the double-sided wiring flexible substrate which concerns on Embodiment 1 of this invention. It is an enlarged view of the A section of FIG. FIG. 4A is a cross-sectional view of the land portion and the through hole. FIG. 4B is a top view of the A part. It is the figure which showed an example of the double-sided wiring flexible substrate which concerns on Embodiment 2 of this invention. FIG. 5A is a cross-sectional configuration diagram of a land portion and a through hole as an example of the double-sided wiring flexible substrate according to the second embodiment. FIG. 5B is a top view of a land portion and a through hole as an example of the double-sided wiring flexible substrate according to the second embodiment. FIG. 6 is an enlarged view of a portion B in FIG. It is the figure which showed an example of the double-sided wiring flexible substrate which concerns on Embodiment 3 of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

Embodiment 1
FIG. 3 is a top view showing an overall configuration of an example of the double-sided wiring flexible substrate according to Embodiment 1 of the present invention. The double-sided wiring flexible substrate according to the first embodiment includes an insulating base material 10, an inner lead portion 20, an upper surface wiring pattern 30, an upper surface land portion 40, a lower surface wiring pattern 80, and an outer lead portion 90. A plurality of inner lead portions 20, upper surface wiring patterns 30, upper surface land portions 40, lower surface wiring patterns 80, and outer lead portions 90 are formed.

  The double-sided wiring flexible substrate is used with a semiconductor chip (not shown) mounted on the upper surface on which the inner lead portion 20, the upper surface wiring pattern 30, and the upper surface land portion 40 are formed. Therefore, the upper surface is a semiconductor chip mounting surface, and the lower surface is a semiconductor chip non-mounting surface. The semiconductor chip mounted on the double-sided wiring flexible substrate may be a variety of semiconductor chips depending on the application. For example, it may be a driving IC chip for driving a display such as a liquid crystal display panel. . A driving circuit for the display is mounted on the driving IC chip.

  In FIG. 3, a plurality of conductors formed at a predetermined pitch are formed in parallel in the width direction of the insulating base material 10 on one surface of the insulating base material 10 made of polyimide or the like as the upper surface wiring pattern 30. One end portion of the conductor is used as an inner lead portion 20 to which an electrode (not shown) of a driving IC chip is connected. The inner lead portion 20 is connected to the upper surface wiring pattern 30, and the upper surface wiring pattern 30 is connected to the land portion 40.

  On the other hand, a lower surface wiring pattern 80 is formed on the surface on which the driving IC chip is not mounted, and one end of the lower surface wiring pattern 80 is an outer lead portion 90 connected to the electrode terminal portion of the liquid crystal display panel. Further, the upper wiring pattern 30 on the driving IC chip mounting surface side and the lower wiring pattern 80 on the non-mounting surface side are plated in a through hole (not shown in FIG. 3) below the land portion 40. The layers are electrically connected.

  As described above, in the double-sided wiring flexible board according to the first embodiment, the upper surface wiring pattern 30 and the lower surface wiring pattern 80 are formed on both surfaces, and both are connected via the through holes at the land portion 40, and the upper surface wiring The pattern 30 is connected to the driving IC via the inner lead portion 20, and the lower surface wiring pattern 80 is connected to the electrode terminal portion of the display via the outer lead portion 90.

  The individual constituent elements will be described in more detail. The insulating base material 10 is a base material made of an insulating film, and is made of a flexible and bendable material. For example, the insulating substrate 10 is configured by appropriately using a material such as polyimide, polyamide, polyethylene terephthalate (PET), or liquid crystal polymer (LCP).

  The inner lead portion 20 is a portion to which a semiconductor chip terminal is connected. For example, the semiconductor chip and the inner lead portion 20 are connected to connection terminals on the semiconductor chip by bumps or the like.

  The upper surface wiring pattern 30 is a wiring for leading the electrical connection from the inner lead portion 20 to the outside while widening the interval between the terminals.

  The upper surface land portion 40 is a terminal for guiding the electrical connection from the upper surface wiring pattern 30 formed on the upper surface of the insulating base material 10 to the lower surface (back surface), and the through hole and the upper surface wiring formed below. Electrical connection with the pattern 30 is performed. Therefore, the upper surface land portion 40 is formed so as to include the through hole while being connected to the upper surface wiring pattern 30.

  In addition, although the inner lead part 20, the upper surface wiring pattern 30, and the upper surface land part 40 may be comprised with the metal wiring material which consists of various conductors, copper may be used, for example. For example, a copper plating layer may be formed on the insulating substrate 10 by copper plating, whereby the inner lead portion 20, the upper surface wiring pattern 30, and the upper surface land portion 40 may be configured.

  Further, since the inner lead portion 20 is an end portion on the semiconductor chip side of the upper surface wiring pattern 30 and the land portion 40 is an end portion on the outer lead portion 90 side of the upper surface wiring pattern 30, It may be considered that the portion constitutes the inner lead portion 20 and the land portion 40.

  The lower surface wiring pattern 80 is a wiring pattern formed on the surface of the insulating substrate 10 on the semiconductor chip non-mounting side, and the outer lead portion 90 is a terminal formed at the outer end of the lower surface wiring pattern 80. . The lower surface wiring pattern 80 and the outer lead portion 90 are also made of the same material as that of the upper surface wiring pattern 30 and the inner lead portion 20 and may have the same structure as those, and thus description thereof is omitted.

  FIG. 4 is an enlarged view of a portion A in FIG. 4A is a cross-sectional view of the land portion and the through hole, and FIG. 4B is a top view of the A portion.

  In FIG. 4A, in addition to the insulating base material 10 and the upper surface land portion 40, a plurality of through holes 50, plating layers 60 and lower surface land portions 70 are shown. The through hole 50 is configured as a through hole penetrating the insulating substrate 10, and a plated layer 60 is formed in the through hole 50 to fill the through hole 50. An upper surface land portion 40 is formed above the opening 52 on the upper surface of the through hole 50, and a lower surface land portion 70 is formed below the opening 53 on the lower surface of the through hole 50. Since the lower surface land portion 70 is made of a metal wiring material similarly to the upper surface land portion 40 and the plating layer 60 is also made of a metal wiring material, electrical connection between the upper surface land portion 40 and the lower surface land portion 70 is performed. However, the plating layer 60 is formed through a through hole 50 filled and formed inside. In addition, although the plating layer 60 and the lower surface land part 70 may also be comprised with the various metal wiring material which consists of a conductor, both may be comprised, for example with a copper plating layer.

  Here, the upper surface land portion 40 is configured to be larger than the lower surface land portion 70 and is configured to cover the lower surface land portion 40. That is, when the double-sided wiring flexible board is viewed from above, the upper surface land portion 40 includes the lower surface land portion 70 and covers the lower surface land portion 70. As described above, since the upper surface land portion 40 and the lower surface land portion 70 are electrically connected through the through hole 50 filled with the plating layer 60, both of the positions include the through hole 50. Formed. Accordingly, if the size of the upper surface land portion 40 is configured to be larger than that of the lower surface land portion 70, the upper surface land portion 40 can include the lower surface land portion 70. With such a configuration, even if a slight misalignment occurs between the upper surface land portion 40 and the lower surface land portion 70, the positional difference is a difference in size between the upper surface land portion 40 and the lower surface land portion 70. If it is within the range, the lower surface land portion 70 is included in the upper surface land portion 40 and does not protrude outward from the upper surface land portion 40. Then, when a transmission-type appearance inspection is performed, an erroneous inspection as described with reference to FIG. 2B can be prevented.

  As shown in FIG. 4B, when the double-sided wiring flexible substrate is viewed from above, the lower surface land portion 70 is included in the upper surface land portion 40 and is covered with the upper surface land portion 40. Further, the upper surface land portion 40 includes the lower surface land portion 70 with a slight margin with respect to the lower surface land portion 70. If the transmission type visual inspection is performed in this state, even if a slight misalignment occurs between the upper surface land portion 40 and the lower surface land portion 70, the upper surface land portion 40 is not displaced as long as it is within the margin range. The state of covering the lower surface land portion 70 is maintained. Therefore, during the transmission-type appearance inspection, the lower surface land portion 70 does not protrude from the upper surface land portion 40, and it is possible to prevent erroneous detection that the wiring is missing.

  On the other hand, when a positional deviation exceeding the margin range of the upper surface land portion 40 has occurred, such a positional deviation can be detected. Therefore, by appropriately setting the difference in size between the upper surface land portion 40 and the lower surface land portion 70, that is, the margin of the upper surface land portion 40, it is possible to appropriately prevent misdetection of the positional displacement within the allowable range of positional displacement. can do.

  As described above, according to the double-sided wiring flexible board according to the present embodiment, it is possible to prevent erroneous detection of a chipping of the wiring due to the positional deviation between the upper surface land portion 40 and the lower surface land portion 70 during the transmission visual inspection. Can do. In addition, by appropriately setting the size difference between the upper surface land portion 40 and the lower surface land portion 70, it is possible to appropriately detect a defect with respect to a positional deviation outside the allowable range.

  In the transmission appearance inspection, first, the double-sided wiring flexible substrate according to the present embodiment is arranged so that the upper surface land portion 40 having a large area becomes the upper surface. Next, a transmission-type appearance inspection is performed from the upper surface of the arranged double-sided wiring flexible substrate. By performing such a transmission type visual inspection method, the visual inspection of the double-sided wiring flexible board is appropriately performed while preventing erroneous detection of chipping of the wiring due to the positional deviation between the upper surface land portion 40 and the lower surface land portion 70. This can be done and the yield can be improved.

[Embodiment 2]
FIG. 5 is a view showing an example of a double-sided wiring flexible board according to Embodiment 2 of the present invention. The double-sided wiring flexible substrate according to the second embodiment is different only in the configuration of the through holes, and the overall configuration is the same as that of FIG. 3 of the first embodiment. Therefore, the double-sided wiring flexible substrate according to the second embodiment will be described only for the parts different from the first embodiment. Therefore, in FIG. 5, the enlarged view of the A section of FIG. 3 is shown.

  FIG. 5A is a cross-sectional configuration diagram of a land portion and a through hole as an example of the double-sided wiring flexible substrate according to the second embodiment. In FIG. 5A, the through hole 53 penetrates the insulating base material 10, the plated layer 61 is filled and formed in the through hole 53, the upper surface land portion 40 covers the opening 54 on the upper surface of the through hole 51, The lower surface land portion 70 covers the lower surface opening 55 from below, similar to the double-sided wiring flexible substrate according to the first embodiment. Further, the upper surface land portion 40 is formed larger than the lower surface land portion 70 and is formed so as to include the lower surface land portion 70 as in the double-sided wiring flexible substrate according to the first embodiment.

  However, in the double-sided wiring flexible board according to the second embodiment, the through hole 53 has different opening widths or opening diameters in the opening 54 on the upper surface and the opening 55 on the lower surface, and has a tapered inclined surface. This is different from the double-sided wiring flexible substrate according to the first embodiment in that it is configured. Since the upper surface land portion 40 is larger than the lower surface land portion 70, in the double-sided wiring flexible board according to the second embodiment, the upper surface land portion 40 and the lower surface land portion 70 have openings corresponding to the sizes of the upper surface land portion 40 and the lower surface land portion 70. The opening diameter of the part 54 is formed larger than the opening diameter of the opening part 55 on the lower surface. Thereby, the side surface of the through hole 53 forms a tapered inclined surface, can be filled with more plating layer 61, and can improve the conductivity in the through hole 53. Further, since the opening 54 on the upper surface is widened during the plating process, the plated layer 61 can be easily filled in the through hole 53, and the filling formation of the plated layer 61 in the through hole 53 is facilitated. Can do.

  As described above, in the double-sided wiring flexible board according to the second embodiment, by utilizing the fact that the area of the upper surface land portion 40 is increased, the opening diameter of the opening portion 54 on the upper surface of the through hole 53 is increased correspondingly. By doing so, the electrical characteristics and workability of the double-sided wiring flexible substrate can be improved.

  FIG. 5B is a top view of a land portion and a through hole as an example of the double-sided wiring flexible substrate according to the second embodiment. Although the relationship between the upper surface land portion 40 and the lower surface land portion 70 is the same as that in the first embodiment, it is shown that the opening 54 on the upper surface of the through hole 53 is larger than that in the first embodiment. Thereby, electroconductivity and plating workability can be improved.

  FIG. 6 is an enlarged view of a portion B in FIG. As shown in FIG. 6, the inclination angle θ of the through hole 53 may be various angles depending on the application. The inclination angle θ of the through hole 53 can be set, for example, in a range of 25 ° to 35 °, but such a setting angle varies depending on the processing method. This point will be described later.

  Moreover, since the transmission type visual inspection method for the double-sided wiring flexible substrate according to the second embodiment can be performed in the same manner as the transmission type visual inspection method for the double-sided wiring flexible substrate according to the first embodiment, the description thereof is omitted. .

  Next, a method for manufacturing a double-sided wiring flexible substrate according to Embodiment 2 of the present invention will be described. It should be noted that the constituent elements described so far are denoted by the same reference numerals and description thereof is omitted.

  First, a tape having copper foil on both surfaces of the insulating substrate 10 is prepared. This may be either a tape provided with a copper layer without an adhesive layer on both sides of the insulating film or a tape provided with a copper layer via a small amount of adhesive layer. In order to form a high-density wiring pattern, it is preferable to use a substrate in which a seed layer such as Ni or Cr is formed on the insulating base material 10 and subsequently a Cu layer is formed without using an adhesive layer. A thinner Cu layer is more preferable for increasing the wiring pattern density.

  As the insulating substrate 10, polyimide, polyamide, polyethylene terephthalate (PET), liquid crystal polymer (LCP), or the like can be used as appropriate.

  Next, after forming the through hole 53, copper plating is performed to obtain conduction of the double-sided copper foil, the copper layer subjected to copper plating, and the through hole which is rendered conductive by the copper plating layer 61 53.

  The through-hole 53 can be formed by a known through-hole forming method such as a punching method using a mold, an etching method, or a laser method. In this embodiment, the lower surface land portion 70 is smaller than the opposed upper surface land portion 40. To do. Therefore, in order to form the small-diameter through-hole opening 55 in the small lower surface land portion 70, it is desirable to form the through-hole 53 by an etching method or a laser method.

  6 shows the inclination angle θ of the through hole 53. In the case of the etching method, the inclination angle θ of the through hole is about 25 ° to 35 °, and in the case of the laser method, the inclination angle is 5 °. It can be formed at 15 °. Therefore, a desired processing method can be appropriately selected in consideration of the wiring width and wiring interval, the thickness of the insulating base material, and the through-hole diameter to be formed.

  Further, the land portions 40 and 70 and the wiring patterns 20, 30, 80, and 90 are formed by an etching method using a photoresist. The wiring pattern is formed through a known dry film resist pasting, exposure, development, etching, and stripping processes.

  At the time of exposure in the etching method, considering the positional accuracy of resist pattern formation on both sides, the size of the lower surface land portion 70 is made smaller than the maximum value of the positional deviation of resist pattern formation. The size of the land portions 40 and 70 is set in advance by an exposure pattern formed on a photomask used when forming a resist pattern, whereby the double-sided wiring flexible substrate according to the present embodiment can be formed.

  In addition, the manufacturing method of the double-sided wiring flexible substrate which concerns on this embodiment is not limited to this, For example, the formation of the land parts 40 and 70 and the wiring patterns 20, 30, 80, and 90 is a plating method other than an etching method Can also be formed.

  In the double-sided wiring flexible substrate according to the first embodiment, the through hole 50 may be formed without providing an inclination, and the processing method may be the same as that of the second embodiment. Moreover, about the other component, the manufacturing method of the double-sided wiring flexible substrate which concerns on Embodiment 2 can be applied as it is.

[Embodiment 3]
FIG. 7 is a view showing an example of a double-sided wiring flexible board according to Embodiment 3 of the present invention. The double-sided flexible substrate according to the third embodiment will be described with respect to an example in which the double-sided wiring flexible substrate according to the first and second embodiments is mounted on a display.

  FIG. 7 shows a state where the double-sided wiring flexible substrate according to the first and second embodiments is mounted on a display. A connection terminal (not shown) provided on the circuit 140 formed on the display panel 110 and an outer lead portion 90 provided on one end of the wiring pattern 80 of the double-sided wiring flexible board are connected to each other on the printed wiring board 120. And the wiring pattern 30 of the double-sided wiring flexible board are connected to each other. The inner lead portion 20 of the double-sided wiring flexible substrate is connected to the electrode of the driving IC chip 100.

  Thus, the double-sided wiring flexible substrate according to Embodiments 1 and 2 can be appropriately mounted on a display and used.

〔Example〕
As an example, the double-sided wiring flexible substrate according to Embodiment 1 shown in FIG. 4 was manufactured.

  First, using a tape in which a 0.5 μm copper layer is formed on both sides of a 25 μm thick polyimide film, and using a UV-YAG laser (AOV LSY-3355) from one side, the upper surface side opening diameter is 20 μm. A through hole was formed. At that time, the diameter of the opening on the lower surface side of the through hole was 10 μm.

  Next, after a known desmear treatment, a 0.3 μm copper layer was formed in the through hole portion by sputtering.

  Next, in order to form a circuit wiring pattern, after laminating the dry film on both sides, the dry film is exposed by exposure, the dry film not exposed to light is removed by development, and the dry film is removed by plating. A copper layer is formed on the formed portion, the dry film remaining in the film removal step is removed, and a double-sided wiring pattern having a wiring width of 10 μm, an upper surface land portion of 100 μm □, and a lower surface land portion of 60 μm is formed. Such a double-sided wiring flexible substrate was obtained.

  When 1000 pieces of the double-sided wiring board manufactured under the above conditions were inspected with a transmission type visual inspection apparatus, the number of erroneous detections as a wiring failure due to the misalignment of the land portion was 0 pieces.

  Thus, according to the double-sided wiring board according to the present example, it was possible to reliably prevent erroneous detection in the transmission visual inspection.

  The preferred embodiments and examples of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments and examples, and the above-described embodiments and examples can be performed without departing from the scope of the present invention. Various modifications and substitutions can be made to the embodiments.

DESCRIPTION OF SYMBOLS 10 Insulating base material 20 Inner lead part 30, 80 Wiring pattern 40, 70 Land part 50, 53 Through hole 51, 52, 54, 55 Opening part 60, 61 Plating layer 90 Outer lead part

Claims (12)

An insulating substrate made of an insulating film;
A through hole penetrating the insulating substrate;
First and second land portions formed on both surfaces of the insulating base so as to include the through holes;
First and second wiring patterns connected to each of the first and second land portions;
The double-sided wiring flexible substrate, wherein the first land portion is larger than the second land portion and includes the second land portion in a top view.   2. The through hole according to claim 1, wherein a size of a first opening formed in the first land portion is larger than a size of a second opening formed in the second land portion. Double-sided wiring flexible board.   The double-sided wiring flexible board according to claim 2, wherein the through hole has an inclined surface that connects the first opening and the second opening.   The double-sided wiring flexible board according to claim 3, wherein the first and the first openings are circular, and the inclined surface is a tapered surface.   The double-sided wiring flexible board according to claim 1, wherein the through hole has a cylindrical shape.   The difference in size between the first land portion and the second land portion is set based on a range that allows positional deviation between the first land portion and the second land portion. The double-sided wiring flexible substrate according to any one of 1 to 5.   The double-sided wiring flexible board according to any one of claims 1 to 6, wherein a plurality of the through holes, the first and second land portions, and the first and second wiring patterns are formed.   The double-sided wiring flexible substrate according to any one of claims 1 to 7, wherein the first wiring pattern is formed on a surface for mounting a semiconductor chip and includes an inner lead to which the semiconductor chip is connected.   The double-sided wiring flexible board according to claim 7, wherein the second wiring pattern includes an outer lead.   The double-sided wiring flexible substrate according to claim 7 or 8, wherein the semiconductor chip is an IC chip for driving a display.   The double-sided wiring flexible board according to any one of claims 1 to 10, wherein the first and second land portions and the first and second wiring patterns are copper plating layers. Placing the double-sided wiring flexible substrate according to any one of claims 1 to 11 so that the first land portion is an upper surface;
A method for inspecting a flexible double-sided wiring board, comprising: a step of performing a transmissive appearance inspection from an upper surface of the first land portion and the second land portion.

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