JP5591384B2 - Wiring circuit board and manufacturing method thereof - Google Patents

Description

  The present invention relates to a printed circuit board and a method for manufacturing the same.

  At the time of manufacturing the printed circuit board, a conductor pattern is formed on the board as a wiring pattern by a subtractive method or the like. Moreover, a connection terminal is formed by electroplating a part of conductor pattern. In order to perform electroplating, it is necessary to supply power to the conductor pattern. Therefore, when the conductor pattern is formed, a power supply wiring portion (hereinafter referred to as a plating lead wire) extending from a portion where the connection terminal is to be formed to one end portion on the substrate is formed. Power is supplied to the conductor pattern from the lead wire for plating.

  For example, according to Patent Document 1, when manufacturing a printed circuit board called BGA (Ball Grid Array) used for a semiconductor device, electrolytic nickel plating and electrolytic gold are formed on a bonding pad of a conductor pattern formed by a subtractive method. Connection terminals are formed by plating.

  Power is supplied by electrically connecting a plating lead wire extending from a bonding pad on the substrate to one end on the substrate with an external plating electrode. Then, after electrolytic nickel plating is performed on the bonding pad, electrolytic gold plating is performed.

JP 2006-287034 A

  However, in the above method, the lead wire for plating remains on the printed circuit board as an unnecessary portion even after the electrolytic plating is completed. When an electrical signal is transmitted through the conductor pattern in a state where another electronic circuit is connected to the connection terminal of the printed circuit board, the lead wire for plating is a stub branched from the transmission line. In such a stub, resonance occurs at a specific frequency. Thereby, a specific frequency component of the electric signal is attenuated. As a result, inconveniences such as a dull waveform of the electric signal may occur.

  The lead wire for plating is unnecessary after the completion of the electrolytic plating. Therefore, it is conceivable to remove the lead wire for plating after the end of electrolytic plating. However, since a process for removing the lead wire for plating is required, the manufacturing cost increases.

  An object of the present invention is to provide a printed circuit board in which an influence of a lead wire for plating on a waveform of an electric signal is reduced, and a manufacturing method thereof.

[1] The present invention
(1) A printed circuit board according to a first invention includes a base insulating layer, a wiring pattern formed on the base insulating layer, a first terminal portion provided at one end of the wiring pattern, and the wiring pattern. 2nd terminal part provided in an edge part, the lead wire for plating formed on a base insulating layer so that it may extend from the 1st terminal part of a wiring pattern, and a wiring pattern except a 1st and 2nd terminal part A cover insulating layer provided on the base insulating layer so as to cover the portion and a plating layer formed on the first terminal portion, wherein the plating lead wire extends from the first terminal portion. It includes a linear part and a plurality of second linear parts extending from the first linear part.
In the printed circuit board, a wiring pattern, first and second terminal portions provided at one end portion and the other end portion of the wiring pattern, and a plating lead wire extending from the first terminal portion are formed on the base insulating layer. It is formed. In this case, the plating lead wire is formed to branch into a plurality of linear portions.
When an electrical signal is transmitted through the wiring pattern, the plating lead wire is branched into a plurality of linear portions, so that the resonance frequency of the plating lead wire is lowered.
Therefore, the resonance frequency in the lead wire for plating can be made lower than the frequency of the electric signal transmitted by the wiring pattern. Thereby, the influence which the resonance in the lead wire for plating has on the waveform of the electric signal can be reduced. As a result, it is possible to suppress the dullness of the waveform of the electric signal due to resonance in the lead wire for plating.
In addition, even if the length of the lead wire for plating is limited due to restrictions on the layout of the printed circuit board, the lead for plating can be made without adjusting the length of the lead wire for plating by branching the lead wire for plating. The resonant frequency in the line can be made lower than the frequency of the electrical signal.
(2) According to a second aspect of the present invention, there is provided a printed circuit board manufacturing method comprising: a wiring pattern; a first terminal provided at one end of the wiring pattern; and a second terminal provided at the other end of the wiring pattern on the insulating base layer. And a step of forming a conductor pattern including a lead wire for plating extending from the first terminal portion of the wiring pattern and the first terminal portion of the wiring pattern, and base insulation so as to cover a portion of the wiring pattern excluding the first and second terminal portions A step of forming a cover insulating layer on the layer, and a step of forming a plating layer on the first terminal portion by supplying power to the wiring pattern through the lead wire for plating. It includes a first linear portion extending from the terminal portion and a plurality of second linear portions extending from the first linear portion.
In the method for manufacturing a printed circuit board, on a base insulating layer, a wiring pattern, first and second terminal portions provided at one end and the other end of the wiring pattern, and plating for extending from the first terminal portion A conductor pattern including lead wires is formed. In this case, the plating lead wire is formed to branch into a plurality of linear portions. By supplying power to the wiring pattern through the lead wire for plating, a plating layer is formed on the terminal portion.
In the printed circuit board manufactured in this way, when an electrical signal is transmitted through the wiring pattern, the plating lead wire branches into a plurality of linear portions, so that the resonance frequency of the plating lead wire is lowered.
Therefore, the resonance frequency in the lead wire for plating can be made lower than the frequency of the electric signal transmitted by the wiring pattern. Thereby, the influence which the resonance in the lead wire for plating has on the waveform of the electric signal can be reduced. As a result, it is possible to suppress the dullness of the waveform of the electric signal due to resonance in the lead wire for plating.
In addition, even if the length of the lead wire for plating is limited due to restrictions on the layout of the printed circuit board, the lead for plating can be made without adjusting the length of the lead wire for plating by branching the lead wire for plating. The resonant frequency in the line can be made lower than the frequency of the electrical signal.
[2] Reference Form (1) A printed circuit board according to a first reference form includes an insulating layer, a wiring pattern formed on the insulating layer, a terminal portion provided in a part of the wiring pattern, and a wiring pattern. The lead wire for plating formed on the insulating layer so as to extend, and the lead wire for plating branches into a plurality of linear portions.

  In the printed circuit board, a wiring pattern, a terminal portion provided in a part of the wiring pattern, and a lead wire for plating extending from the wiring pattern are formed on the insulating layer. In this case, the plating lead wire is formed to branch into a plurality of linear portions.

  When an electrical signal is transmitted through the wiring pattern, the plating lead wire is branched into a plurality of linear portions, so that the resonance frequency of the plating lead wire is lowered.

  Therefore, the resonance frequency in the lead wire for plating can be made lower than the frequency of the electric signal transmitted by the wiring pattern. Thereby, the influence which the resonance in the lead wire for plating has on the waveform of the electric signal can be reduced. As a result, it is possible to suppress the dullness of the waveform of the electric signal due to resonance in the lead wire for plating.

  In addition, even if the length of the lead wire for plating is limited due to restrictions on the layout of the printed circuit board, the lead for plating can be made without adjusting the length of the lead wire for plating by branching the lead wire for plating. The resonant frequency in the line can be made lower than the frequency of the electrical signal.

  (2) The lead wire for plating may include a third linear portion extending from the wiring pattern and a plurality of fourth linear portions extending from the third linear portion.

  In this case, it is possible to reduce the resonance frequency of the plating lead wire while suppressing an increase in the arrangement space of the plating lead wire.

(3) In the method for manufacturing a printed circuit board according to the second embodiment , a conductive pattern including a wiring pattern, a terminal portion provided in a part of the wiring pattern, and a lead wire for plating extending from the wiring pattern is formed on the insulating layer. Forming a plating layer on the terminal portion by supplying power to the wiring pattern through the lead wire for plating, and in the step of forming the conductor pattern, the lead wire for plating is formed into a plurality of linear portions. It is to be branched.

  In the method for manufacturing a printed circuit board, a conductor pattern including a wiring pattern, a terminal portion provided in a part of the wiring pattern, and a lead wire for plating extending from the wiring pattern is formed on the insulating layer. In this case, the plating lead wire is formed to branch into a plurality of linear portions. By supplying power to the wiring pattern through the lead wire for plating, a plating layer is formed on the terminal portion.

  In the printed circuit board manufactured in this way, when an electrical signal is transmitted through the wiring pattern, the plating lead wire branches into a plurality of linear portions, so that the resonance frequency of the plating lead wire is lowered.

  Therefore, the resonance frequency in the lead wire for plating can be made lower than the frequency of the electric signal transmitted by the wiring pattern. Thereby, the influence which the resonance in the lead wire for plating has on the waveform of the electric signal can be reduced. As a result, it is possible to suppress the dullness of the waveform of the electric signal due to resonance in the lead wire for plating.

  In addition, even if the length of the lead wire for plating is limited due to restrictions on the layout of the printed circuit board, the lead for plating can be made without adjusting the length of the lead wire for plating by branching the lead wire for plating. The resonant frequency in the line can be made lower than the frequency of the electrical signal.

  According to the present invention, the influence of resonance in the plating lead wire on the waveform of the electric signal can be reduced. As a result, it is possible to suppress the dullness of the waveform of the electric signal due to resonance in the lead wire for plating.

It is a top view of a suspension board. It is a typical longitudinal cross-sectional view of the lead wire for plating and its peripheral part. It is an enlarged plan view of the lead wire for plating and its peripheral part. It is typical process sectional drawing which shows the manufacturing process of a suspension board. It is a typical sectional view of an FPC board. It is typical sectional drawing which shows the connection state of the electrode pad of a suspension board, and the terminal part of FPC board. It is an enlarged plan view of the lead wire for plating and its peripheral part. It is an enlarged plan view of the lead wire for plating and its peripheral part. It is an enlarged plan view of the lead wire for plating and its peripheral part.

  Hereinafter, a printed circuit board according to a reference embodiment and an embodiment of the present invention and a manufacturing method thereof will be described with reference to the drawings. In the following reference embodiments and embodiments, a suspension board used for reading and writing of a hard disk will be described as an example of a printed circuit board.

(1) Structure of Suspension Board FIG. 1 is a top view of a suspension board according to a reference embodiment of the present invention. As shown in FIG. 1, the suspension board 1 includes a suspension main body 10 formed of a long metal substrate. A plurality of holes H are formed in the suspension body 10. A plurality of wiring patterns 20 are formed on the suspension body 10. Electrode pads 23 and 30 are respectively provided at one end and the other end of each wiring pattern 20.

  A magnetic head mounting portion (hereinafter referred to as a tongue portion) 12 is provided at the distal end portion of the suspension main body portion 10 by forming a U-shaped opening 21. The tongue portion 12 is bent at a location indicated by a broken line R so as to form a predetermined angle with respect to the suspension main body portion 10. A plurality of electrode pads 23 are formed at the end of the tongue 12.

  On the tongue unit 12, a magnetic head (not shown) for reading from and writing to the hard disk is mounted. The terminal portion of the magnetic head is connected to each of the plurality of electrode pads 23.

  A plurality of electrode pads 30 are formed on the other end of the suspension body 10. A plurality of plating lead wires S are formed so as to extend from the plurality of electrode pads 30 to the opposite side of the wiring pattern 20.

  During manufacturing, after a plurality of suspension boards 1 are simultaneously formed on a metal support board 50, each suspension board 1 is separated from other areas of the support board 50. In this case, the suspension main body 10 is composed of a part of the support substrate 50.

  The plurality of lead wires S for plating of each suspension board 1 extend to a region on the support board 50 outside each suspension board 1 and connected to a power supply terminal (not shown). After each suspension board 1 is completed, each suspension body 10 is separated from the other regions of the support board 50 at a one-dot chain line Z1.

  FIG. 2 is a schematic cross-sectional view of the lead wire S for plating and the peripheral portion thereof. FIG. 3 is an enlarged plan view of the plating lead wire S and its peripheral portion.

  As shown in FIG. 2, a base insulating layer 11 made of, for example, polyimide is formed on a suspension body 10 made of, for example, stainless steel (SUS).

  On the base insulating layer 11, a plurality of wiring patterns 20 made of, for example, copper and a plurality of lead wires S for plating are formed. In FIG. 2, only one wiring pattern 20 and one plating lead wire S are shown.

  Each wiring pattern 20 and each plating lead S are formed integrally with each other. In this case, an electrode pad 30 is provided at the end of each wiring pattern 20, and a plating lead S is provided so as to extend from each electrode pad 30 to the opposite side of the wiring pattern 20.

  A cover insulating layer 13 made of polyimide, for example, is formed on the base insulating layer 11 so as to cover the plurality of lead wires S for plating and the plurality of wiring patterns 20.

  A hole 14 reaching the upper surface of each electrode pad 30 is formed in a portion of the insulating cover layer 13 on the electrode pad 30 of each wiring pattern 20. A plating layer 30a made of, for example, gold is formed so as to fill the hole 14.

  As shown in FIG. 3, the width H <b> 1 of each plating lead S is set larger than the width H <b> 2 of each wiring pattern 20. The width H1 of each lead wire S for plating is preferably greater than 1 and less than or equal to 10 times the width H2 of each wiring pattern 20. Here, when the width of the wiring pattern 20 is not uniform, the width H2 of the wiring pattern 20 refers to the minimum value of the width of the wiring pattern 20.

(2) Method for Manufacturing Suspension Board Hereinafter, a method for manufacturing the suspension board 1 according to this embodiment will be described. Here, the description about the formation process of the tongue part 12, the several electrode pad 23, and the hole H of FIG. 1 is abbreviate | omitted.

  FIG. 4 is a schematic process cross-sectional view showing the manufacturing process of the suspension board 1 according to the reference embodiment of the present invention. FIG. 4 shows a manufacturing process in a cross section at the same location as FIG.

  First, a support substrate 50 made of, for example, stainless steel (SUS) is prepared. Next, as shown in FIG. 4A, the base insulating layer 11 made of, for example, polyimide is formed on the support substrate 50.

  As a material of the support substrate 50, other materials such as aluminum may be used instead of stainless steel. The thickness of the support substrate 50 is preferably 5 μm or more and 200 μm or less, and more preferably 10 μm or more and 50 μm or less.

  As a material of the base insulating layer 11, other insulating materials such as epoxy may be used instead of polyimide. The thickness of the base insulating layer 11 is preferably 1 μm or more and 100 μm or less, and more preferably 2 μm or more and 25 μm or less.

  Next, as shown in FIG. 4B, a plurality (one in FIG. 4) of wiring patterns 20 and a plurality of (one in FIG. 4) plating leads S made of, for example, copper on the base insulating layer 11. Form. In this case, an electrode pad 30 is provided at the end of each wiring pattern 20, and a plating lead S is provided so as to extend from each electrode pad 30 to the opposite side of the wiring pattern 20.

  The wiring pattern 20 and the lead wire S for plating may be formed using, for example, a semi-additive method, or may be formed using another method such as a subtractive method. As a material for the wiring pattern 20 and the plating lead wire S, other metal such as gold or aluminum, or an alloy such as copper alloy or aluminum alloy may be used instead of copper.

  The thickness of the wiring pattern 20 and the lead wire S for plating is, for example, preferably 2 μm or more and 100 μm or less, and more preferably 3 μm or more and 25 μm or less. For example, the width of the wiring pattern 20 is preferably 5 μm or more and 1000 μm or less, and more preferably 10 μm or more and 250 μm or less. The width of the lead wire S for plating is, for example, preferably 5 μm or more and 1000 μm or less, and more preferably 10 μm or more and 250 μm or less.

  Next, as shown in FIG. 4C, a cover insulating layer 13 made of polyimide, for example, is formed on the base insulating layer 11 so as to cover the plurality of wiring patterns 20 and the lead wires S for plating. As the material of the insulating cover layer 13, other materials such as epoxy may be used instead of polyimide.

  Next, as shown in FIG. 4D, a hole 14 reaching the upper surface of the electrode pad 30 is formed in the cover insulating layer 13 on the electrode pad 30 of each wiring pattern 20 by, for example, etching or laser processing. To do.

  Next, as shown in FIG. 4E, a plating layer 30a made of, for example, gold is formed so as to fill the hole 14 by electrolytic plating. In this case, power supply for electrolytic plating is performed through the lead wire S for plating. After the plating layer 30a is formed, the support substrate 50, the base insulating layer 11, the plating lead wire S, and the insulating cover layer 13 are cut along the alternate long and short dash line Z1. Thereby, the suspension board 1 having the suspension body 10 is completed.

(3) Joining of Suspension Board and FPC Board The plurality of electrode pads 30 of the suspension board 1 are joined to terminal portions of other wiring circuit boards (for example, flexible wiring circuit boards). Hereinafter, a bonding example between the electrode pad 30 of the suspension board 1 and a terminal portion of a flexible printed circuit board (hereinafter referred to as an FPC board) will be described.

  FIG. 5 is a schematic cross-sectional view of the FPC board, and FIG. 6 is a schematic cross-sectional view showing a connection state between the electrode pads 30 of the suspension board 1 and the terminal portions of the FPC board. In FIG. 6, the FPC board of FIG. 5 is shown upside down.

  As shown in FIG. 5, the FPC board 100a includes a base insulating layer 41 made of polyimide, for example. On the base insulating layer 41, a plurality of wiring patterns 42 made of, for example, copper are formed. In FIG. 5 and FIG. 6, only one wiring pattern 42 is shown.

  A terminal portion 45 is formed at the end of each wiring pattern 42. A cover insulating layer 43 made of polyimide, for example, is formed on the base insulating layer 41 so as to cover the plurality of wiring patterns 42. A hole 44 is formed in the portion of the insulating cover layer 43 on the terminal portion 45 of each wiring pattern 42. A plating layer 45 a made of, for example, gold is formed so as to fill each hole 44.

  As shown in FIG. 6, the suspension board 1 and the FPC board 100a are arranged so that the electrode pad 30 of the suspension board 1 and the terminal portion 45 of the FPC board 100a are in contact with each other. 30 (plating layer 30a) and the terminal part 45 (plating layer 45a) are joined together.

(4) Attenuation of frequency component by plating lead S Here, the attenuation of the frequency component by the plating lead S when an electric signal is transmitted between the suspension board 1 and the FPC board 100a will be described.

  When electric signals are transmitted through the wiring pattern 20 of the suspension board 1 and the wiring pattern 42 of the FPC board 100a, the wiring pattern 20 and the wiring pattern 42 become transmission paths, and the plating lead wire S becomes a stub branching from the transmission path. .

  In this case, resonance occurs at a specific frequency in the stub. Thereby, the component of the resonance frequency of the electric signal transmitted through the transmission path is attenuated.

  A digital signal includes a plurality of frequency components. For example, a digital signal composed of a rectangular wave includes a plurality of frequency components that are integral multiples of the frequency. Therefore, when a specific frequency component included in the digital signal is attenuated, the waveform of the digital signal becomes dull, and the slopes of the rising edge and the falling edge become gentle.

  In this reference embodiment, the width H1 (FIG. 3) of the lead wire S for plating is set larger than the width H2 (FIG. 3) of the wiring pattern 20. In this case, the resonance frequency of the plating lead wire S is lower than when the width H1 of the plating lead wire S is equal to the width H2 of the wiring pattern 20.

  In the present embodiment, the width H1 of the plating lead wire S is set so that the resonance frequency of the plating lead wire S is lower than the frequency of the electrical signal transmitted through the wiring pattern 20.

(5) Effects of this reference embodiment In the suspension board 1 according to this reference embodiment, the width H1 of the plating lead wire S is set to be larger than the width H2 of the wiring pattern 20, whereby the width H1 of the plating lead wire S is set. Is equal to the width H2 of the wiring pattern 20, the resonance frequency of the lead wire S for plating is lowered. By increasing the width H1 of the plating lead wire S to make the resonance frequency of the plating lead wire S lower than the frequency of the electric signal, the influence of the resonance of the plating lead wire S on the waveform of the electric signal is reduced. can do. As a result, it is possible to suppress the blunting of the waveform of the electric signal due to resonance in the plating lead wire S.

  Further, even when the length of the lead wire S for plating is limited due to restrictions on the layout of the suspension board 1, the width H1 of the lead wire S for plating is adjusted without adjusting the length of the lead wire S for plating. Thereby, the resonance frequency in the lead wire S for plating can be made lower than the frequency of the electric signal.

(6) Other Examples of Lead Wire for Plating In the suspension board 1 described above, the lead wire for plating shown below may be provided in place of the lead wire S for plating.

(6-1)
FIG. 7 is an enlarged plan view of the lead wire Sa for plating and the peripheral portion thereof. In FIG. 7, only one lead wire Sa for plating among the plurality of lead wires Sa for plating is shown.

  As shown in FIG. 7, the lead wire Sa for plating is composed of linear portions S1 and S2 formed integrally with each other. The linear portion S1 is provided so as to extend a predetermined length from the electrode pad 30 to the side opposite to the wiring pattern 20. The linear portion S2 is provided so as to extend from the end portion of the first linear portion S1 to the end portion of the suspension main body portion 10.

  The width H4 of the linear part S2 is set larger than the width H3 of the linear part S1. The width H4 of the linear part S2 is, for example, 1.1 to 10 times, preferably 1.5 to 8 times the width H3 of the linear part S1.

  The ratio of the length of the linear portion S2 to the entire length of the lead wire Sa for plating is, for example, 0.1 or more and 0.9 or less, and preferably 0.2 or more and 0.8 or less.

  By setting the width H4 of the linear portion S2 of the lead wire Sa for plating larger than the width H3 of the linear portion S1, the width H4 of the linear portion S2 is equal to the width H3 of the linear portion S1. Thus, the resonance frequency of the lead wire Sa for plating is lowered. In this case, by making the width H4 of the linear portion S2 of the plating lead Sa larger than the width H3 of the linear portion S1, the resonance frequency in the plating lead Sa is made lower than the frequency of the electrical signal, The influence of resonance in the plating lead Sa on the waveform of the electric signal can be reduced. As a result, it is possible to suppress the dullness of the waveform of the electric signal due to resonance in the plating lead Sa.

  Even when the length of the lead wire Sa for plating is limited due to restrictions on the layout of the suspension board 1, the widths H3 and H4 of the linear portions S1 and S2 are not adjusted without adjusting the length of the lead wire Sa for plating. By adjusting the resonance frequency, the resonance frequency of the plating lead Sa can be made lower than the frequency of the electric signal.

(6-2)
FIG. 8 is an enlarged plan view of the plating lead wire Sb and its peripheral portion. FIG. 8 shows only one plating lead wire Sb among the plurality of plating lead wires Sb.

  As shown in FIG. 8, the plating lead wire Sb is composed of linear portions S3 and S4 that are integrally formed with each other. The linear portion S3 is provided so as to extend from the electrode pad 30 to the opposite side of the wiring pattern 20 by a predetermined length. The linear portion S4 is provided so as to extend from the end portion of the linear portion S3 to the end portion of the suspension main body portion 10.

  The width H5 of the linear portion S3 is set larger than the width H6 of the linear portion S4. The width H5 of the linear portion S3 is, for example, 1.1 to 10 times, preferably 1.5 to 8 times the width H6 of the linear portion S4.

  Further, the ratio of the length of the linear portion S3 to the entire length of the plating lead wire Sb is, for example, 0.1 or more and 0.9 or less, and preferably 0.2 or more and 0.8 or less.

  By setting the width H5 of the linear portion S3 of the lead wire Sb for plating larger than the width H6 of the linear portion S4, the width H5 of the linear portion S3 is equal to the width H6 of the linear portion S4. Thus, the resonance frequency of the lead wire Sb for plating is increased. In this case, by making the width H5 of the linear portion S3 of the plating lead wire Sb larger than the width H6 of the linear portion S4, the resonance frequency in the plating lead wire Sb is made higher than the frequency of the electrical signal, The influence of resonance in the plating lead wire Sb on the waveform of the electric signal can be reduced. As a result, it is possible to suppress the blunting of the waveform of the electric signal due to resonance in the plating lead wire Sb.

  Even if the length of the lead wire Sb for plating is limited due to restrictions on the layout of the suspension board 1, the widths H5 and H6 of the linear portions S3 and S4 are not adjusted without adjusting the length of the lead wire Sb for plating. By adjusting the resonance frequency, the resonance frequency of the plating lead wire Sb can be made higher than the frequency of the electric signal.

(6-3)
FIG. 9 is an enlarged plan view of the plating lead wire Sc and its peripheral portion. In FIG. 9, only one plating lead wire Sc among the plurality of plating lead wires Sc is shown. The suspension board 1 according to the embodiment of the present invention includes the plating lead wire Sc of FIG. 9 instead of the plating lead wire S described above.

  As shown in FIG. 9, the lead wire Sc for plating includes linear portions S5, S6, and S7 that are integrally formed with each other. The linear part S5 is provided so as to extend from the electrode pad 30 to a side opposite to the wiring pattern 20 by a predetermined length. The linear portions S6 and S7 are provided so as to extend from the end portion of the linear portion S5 to the end portion of the suspension main body portion 10, respectively.

  The ratio of the length of the linear portion S5 to the total length of the lead wire Sc for plating (the total length of the linear portions S5, S6, S7) is, for example, 0.1 or more and 0.9 or less, and 0 It is preferable that it is 2 or more and 0.8 or less. The lengths of the linear portions S6 and S7 are preferably equal to each other.

  Since the linear portion S5 of the plating lead wire Sc is branched into the linear portions S6 and S7, the resonance frequency of the plating lead wire Sc is lower than when the plating lead wire Sc is not branched. In this case, the plating lead wire Sc is made by making the resonance frequency of the plating lead wire Sc lower than the frequency of the electric signal by branching the linear portion S5 of the plating lead wire Sc into the linear portions S6 and S7. It is possible to reduce the influence of the resonance in the waveform of the electric signal. As a result, it is possible to suppress the dullness of the waveform of the electric signal due to resonance in the plating lead wire Sc.

  Further, even when the length of the lead wire Sc for plating is limited due to restrictions on the layout of the suspension board 1, by branching the lead wire Sc for plating without adjusting the length of the lead wire Sc for plating, The resonance frequency of the lead wire Sc for plating can be made lower than the frequency of the electric signal.

(7) Reference Example, Example and Comparative Example The influence on the electrical signal due to resonance in the lead wire for plating was determined by simulation. In this case, the suspension body 10 is not provided, and the wiring pattern 20 and the plating lead wires S (Sa to Sc) made of copper are provided on the base insulating layer 11 made of polyimide. The case where an electric signal is transmitted through the pattern 20 is assumed.

  In the following Reference Examples 1 to 5, Examples 1 and 2, and Comparative Example, the thickness of the insulating base layer 11 is 20 μm, the thickness of the wiring pattern 20 is 12 μm, and the width H2 of the wiring pattern 20 is The thickness was 100 μm.

(7-1) Reference Example 1
In the reference example 1, the case where the lead wire S for plating of FIG. 3 is provided was assumed.

  In Reference Example 1, the thickness of the plating lead wire S was 12 μm, the width H1 of the plating lead wire S was 300 μm, and the length of the plating lead wire S was 4800 μm.

(7-2) Reference Example 2
In the reference example 2, the case where the lead wire Sa for plating of FIG. 7 is provided was assumed.

  In Reference Example 2, the thickness of the lead wire Sa for plating is 12 μm, the width H3 of the linear portion S1 is 100 μm, the width H4 of the linear portion S2 is 300 μm, and the length of the linear portion S1 is 2400 μm. The length of the linear portion S2 was 2400 μm.

(7-3) Reference Examples 3-5
In Reference Examples 3 to 5, it was assumed that the lead wire Sb for plating of FIG. 8 is provided.

  In Reference Examples 3 to 5, the thickness of the lead wire Sb for plating was 12 μm, the width H5 of the linear portion S3 was 300 μm, and the width H6 of the linear portion S4 was 100 μm.

  In Reference Example 3, the length of the linear portion S3 was 2400 μm, and the length of the linear portion S4 was 2400 μm. In Reference Example 4, the length of the linear portion S3 was 1200 μm, and the length of the linear portion S4 was 3600 μm. In Reference Example 5, the length of the linear portion S3 was 600 μm, and the length of the linear portion S4 was 4200 μm.

(7-4) Examples 1 and 2
In Examples 1 and 2, it is assumed that the lead wire Sc for plating of FIG. 9 is provided.

  In Examples 1 and 2, the thickness of the lead wire Sc for plating is 12 μm, the width H7 of the linear portion S5 is 100 μm, the width H8 of the linear portion S6 is 100 μm, and the width H9 of the linear portion S7 is 100 μm. It was.

  In Example 1, the length of the linear portion S5 was 2400 μm, and the length of the linear portions S6 and S7 was 2400 μm, respectively. In Example 2, the length of the linear portion S5 was 3600 μm, and the length of the linear portions S6 and S7 was 1200 μm.

(7-5) Comparative Example In the comparative example, the same configuration as the reference example 1 was assumed except that a plating lead wire having the same width as the wiring pattern 20 was provided instead of the plating lead wire S.

(7-6) Evaluation of Reference Examples 1 to 5, Examples 1 and 2, and Comparative Example The electrical signal permeability in Reference Examples 1 to 5, Examples 1 and 2, and Comparative Example was determined by simulation.

  Note that the length of the lead wire S for plating in Reference Example 1, the length of the lead wire Sa for plating in Reference Example 2 (the total length of the linear portions S1 and S2), and the lead for plating in Reference Examples 3 to 5 The length of the wire Sb (the total length of the linear portions S3, S4), the length of the lead wire Sc for plating of Examples 1 and 2 (the total length of the linear portions S5, S6 (S7)), and The lengths of the lead wires for plating in the comparative example are equal to each other.

  As a result of the simulation, in Reference Example 1, a large attenuation of the electric signal occurred with a peak at about 9.4 GHz. In Reference Example 2, a large attenuation of the electric signal occurred with a peak at about 6.7 GHz. In Reference Example 3, a large attenuation of the electric signal occurred with a peak at about 12.2 GHz. In Reference Example 4, a large attenuation of the electric signal occurred with a peak at about 11.2 GHz. In Reference Example 5, the electric signal was greatly attenuated with a peak at about 10.4 GHz. In Example 1, the electric signal was greatly attenuated with a peak at about 7.4 GHz. In Example 2, the electric signal was greatly attenuated with a peak at about 7.7 GHz. On the other hand, in the comparative example, a large attenuation of the electric signal occurred with a peak at about 9.6 GHz.

  Thus, in Reference Examples 1 and 2 and Examples 1 and 2, a large attenuation of the electric signal occurs in a lower frequency region as compared with the comparative example, and in Reference Examples 3 to 5, compared with the comparative example. In the higher frequency range, a large attenuation of the electrical signal occurred.

  As a result, since the width H1 of the plating lead wire S is larger than the width H2 of the wiring pattern 20, the electrical signal is greatly attenuated compared to the case where the width H1 of the plating lead wire S is equal to the width H2 of the wiring pattern 20. It has been found that the frequency region in which is generated becomes lower.

  Further, when the width H4 of the linear portion S2 of the lead wire Sa for plating is set larger than the width H3 of the linear portion S1, the width H4 of the linear portion S2 is equal to the width H3 of the linear portion S1. It was found that the frequency region in which the electrical signal is greatly attenuated is lower than that in FIG.

  Further, when the width H6 of the linear portion S4 of the lead wire Sb for plating is set smaller than the width H5 of the linear portion S3, the width H6 of the linear portion S4 is equal to the width H5 of the linear portion S3. It was found that the frequency region in which a large attenuation of the electric signal occurs is higher than that in FIG.

  In addition, it was found that the frequency region in which the electric signal is greatly attenuated is lower when the plating lead Sc is branched into the linear portions S6 and S7 than when the plating lead Sc is not branched. .

  Therefore, it has been found that the influence of the resonance in the plating lead wire on the waveform of the electric signal can be reduced in a predetermined frequency region (in this example, about 9.6 GHz).

(8) Correspondence relationship between each component of claim and each part of embodiment and reference embodiment Hereinafter, an example of a correspondence between each component of the claim and each part of the embodiment and the reference embodiment will be described. The invention is not limited to the following examples.

  In the above embodiment and reference embodiment, the base insulating layer 11 is an example of an insulating layer, the electrode pad 30 is an example of a terminal portion, the suspension board 1 is an example of a printed circuit board, and the wiring pattern 20 is a wiring. It is an example of a pattern, the lead wire Sc for plating is an example of the lead wire for plating, the linear part S5 is an example of the third linear part, and the linear parts S6 and S7 are the fourth linear part. It is an example.

  As each constituent element in the claims, various other elements having configurations or functions described in the claims can be used.

  The present invention can be effectively used for various printed circuit boards.

DESCRIPTION OF SYMBOLS 1 Suspension board 10 Suspension main body part 11 Base insulating layer 12 Tongue part 13 Cover insulating layer 20 Wiring pattern 23,30 Electrode pad 30a, 45a Plating layer 50 Support board 100a FPC board S Plating lead wire S1-S7 Linear part

Claims (2)

A base insulating layer;
A wiring pattern formed on the base insulating layer;
A first terminal provided at one end of the wiring pattern;
A second terminal provided at the other end of the wiring pattern;
A lead wire for plating formed on the insulating base layer so as to extend from the first terminal portion of the wiring pattern;
A cover insulating layer provided on the base insulating layer so as to cover a portion of the wiring pattern excluding the first and second terminal portions;
A plating layer formed on the first terminal portion ,
The lead wire for plating is
A first linear portion extending from the first terminal portion;
A printed circuit board comprising a plurality of second linear portions extending from the first linear portions and extending . On the base insulating layer, a wiring pattern, a first terminal provided at one end of the wiring pattern, a second terminal provided at the other end of the wiring pattern , and the first terminal of the wiring pattern Forming a conductor pattern including a lead wire for plating extending from the portion ;
Forming an insulating cover layer on the insulating base layer so as to cover a portion of the wiring pattern excluding the first and second terminal portions;
Forming a plating layer on the first terminal portion by supplying power to the wiring pattern through the lead wire for plating,
The lead wire for plating is
A first linear portion extending from the first terminal portion;
A method of manufacturing a printed circuit board, comprising: a plurality of second linear parts extending from the first linear part .

Images