TWI399151B - A manufacturing method of a multilayer printed wiring board and a substrate holder, and a shielding plate - Google Patents

Description

Method for manufacturing multilayer printed wiring board, substrate holder, and shielding plate

The present invention relates to a method of manufacturing a multilayer printed wiring board, a substrate holder, and a shielding plate, and more particularly to a multilayer flexible printed wiring board for single-sided plating which is subjected to plating treatment only on a via hole opening surface. The manufacturing method, the substrate holder used for manufacturing the multilayer printed wiring board, and the shielding board.

In recent years, mounting substrates mounted on small electronic devices such as mobile phones have become more demanding for miniaturization and higher density. In one aspect of the miniaturization and high-density technology of such a mounting substrate, a multilayer flexible printing having a flexible cable portion in which a mounting substrate portion and a flexible cable portion for mounting various electronic components are integrated is disclosed. In the technique of the wiring board, the multilayer flexible printed wiring board based on this technology is widely used for the use of small electronic devices such as mobile phones (see, for example, Patent Document 1 and Patent Document 2).

According to the mainstream of the multilayer flexible printed wiring board according to the technology, a hole is drilled in the wiring board by means of NC drilling or a metal mold, and a through hole plating is applied, and then a circuit is formed on both sides of the substrate. The so-called through-hole connection of both sides of the substrate. However, with the miniaturization and high performance of the electronic device, the substrate is mounted at a higher density, and the terminal for inserting the electronic component into the through hole for mounting the component is gradually formed, and the electronic component is converted. Surface mounted directly on the substrate. Therefore, when the through hole for mounting the surface component exists on the component mounting pad, the solder may flow toward the substrate surface on the opposite side, and the component may not be mounted normally.

Therefore, a fine bottomed via hole is formed by a laser, a plasma or a resin etching method, and a plating process is performed thereon to perform blind hole mounting of the electronic component even if the via hole exists on the component mounting pad (blind The method of connecting via holes is used for a mobile device that is moving toward miniaturization centering on the vicinity of the liquid crystal of the mobile phone.

However, in this method, since the plating treatment is applied to both sides of the substrate, the thickness of the conductor is increased even on the non-opening surface side of the via hole, and thus it becomes difficult to follow the photosensitive etching ( The circuit pattern formed by the etching process of the photofabrication method (etching method based on exposure processing) is miniaturized.

Accordingly, in order to solve such a drawback, a technique of performing a plating treatment on a multilayer flexible printed wiring board using the above-described through hole or blind via connection has been disclosed, and a technique of performing plating treatment using a frame type substrate holder (for example, Refer to Patent Document 3 and Patent Document 4). In other words, according to this technique, in the frame type substrate holder, the shielding plate for uniformizing the plating thickness in the surface of the substrate is provided on the upper and lower left and right peripheral portions on both sides of the frame.

Further, in order to avoid the influence of the uneven thickness of the plating due to the individual difference of the frame type substrate holder, a technique of using a hanging type substrate holder has been used instead of the frame type substrate holder (for example, refer to Patent Document 5) ). According to the technique, in order to avoid the influence of the uneven thickness of the plating, the frame type substrate holder is not used, and the surface is used for the suspension type substrate holder which is traversely supported on the cathode rod, and the circuit substrate to be plated is used. The upper portion is held in a suspended state and a plurality of circuit substrates are adjacent. Then, in a state in which a plurality of circuit substrates are adjacent to each other, power is supplied from the cathode rod to the upper portion of the product via the hanging substrate holder, and the cathode rod travels horizontally and horizontally in the plating solution in the plating bath along the cathode rod. Electrolytic plating treatment is carried out using a so-called frameless plating apparatus.

However, in order to use such a plating apparatus, only one side of the substrate is subjected to a plating treatment, and it is necessary to use a plating mask for the non-electroplating surface. Therefore, the formation step of the plating mask which is more necessary for masking and the peeling step for peeling off the mask are caused by an increase in the production cost of the plating treatment and a decrease in the yield of the product.

Moreover, as an example of a method of performing a plating process only on the opening surface of the via hole of the double-sided flexible printed wiring board, a method of manufacturing a double-sided flexible printed wiring board is disclosed, and two double-sided copper-clad laminates are disclosed. A conductive film is formed by bonding a double-sided micro-adhesive film or the like so that the opening of the via hole faces outward, and the via hole is plated in this manner, and then the plating film is formed only on the open surface side of the via hole by peeling off the micro-adhesive film. . (for example, refer to Patent Document 6)

According to this technique, there is an advantage that the through-hole plating of the two-sided flexible printed wiring board can be collectively performed, but it is complicated by the bonding of the micro-adhesive film, the peeling step, and the like. In particular, a multilayer flexible printed wiring board is difficult to perform a plating process by a roll-to-roll method like a double-sided flexible printed wiring board. In other words, in the case of the reel type plating treatment, the lamination of the microadhesive film and the peeling step thereof may be continuously performed. However, when the short sheets are bonded and peeled off, the processing cost is increased.

Further, in the case of using a heat-expandable film, it is also necessary to carry out the treatment of the film residue after peeling off the heat-expandable film. Therefore, the cost of such auxiliary materials becomes high. Further, there is a concern that the quality of the plating bath of the microadhesive film or the heat-expandable film or the etching failure caused by the residual glue or the poor terminal plating may be lowered.

Then, in order to solve such disadvantages, a method of performing electrolytic plating treatment in a state in which the back surfaces of two circuit substrates are aligned in parallel is disclosed (for example, refer to Patent Document 7). According to this technique, the back surface side of each circuit substrate is not subjected to plating treatment because the electric field is shielded by the shielding plate, but plating treatment of a desired thickness can be performed on the surface side of each circuit substrate. However, in the case where the substrate holder is not provided in the central portion between the anodes and there is a difference in distance between the anode and the circuit substrate due to individual differences in the plating apparatus, etc., the thickness of the electrolytic plating is generated depending on the difference in plating solution resistance. The deviation makes it difficult to refine the circuit pattern formed by the etching process by the photosensitive etching method.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 3776304

[Patent Document 2] Japanese Patent No. 4236837

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2006-291337

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2008-138257

[Patent Document 5] Japanese Patent Laid-Open Publication No. 2006-316322

[Patent Document 6] Japanese Patent Laid-Open Publication No. 2006-086358

[Patent Document 7] Japanese Patent Laid-Open No. Hei 11-229196

According to the above-described circumstances, it is desired to realize a method of manufacturing a multilayer printed wiring board which can perform uniform plating treatment only on the opening surface of the via hole of the multilayer printed wiring board, which is more convenient and free from contamination by electroplating bath.

Therefore, in order to provide a simple method, without the use of an auxiliary material and without the contamination of the plating bath, it is possible to inexpensively and stably manufacture a multilayer printed wiring board capable of forming a multilayer printed wiring board of a plating film only on the opening surface of the via hole of one side. The manufacturing method, the substrate holder for manufacturing the multilayer printed wiring board, and the shielding plate are the technical problems to be solved, and an object of the present invention is to solve the problem.

The present invention provides a method for producing a multilayer printed wiring board, which comprises the first step of forming a conductive layer having three or more layers and a dielectric layer according to the first aspect of the invention. a circuit substrate of the insulating layer between the conductive layers; and a second step of forming only one of the openings in the path from the conductive layer of the outermost layer of the circuit substrate to the conductive layer of the other outermost layer a non-penetrating conductive common hole of the portion; a third step of conducting a conductive treatment on the inner wall of the conductive common hole; and a fourth step of preparing a substrate holder equipped with a shielding plate having a circuit substrate covering the foregoing The area of one side has a length extending downward from the circuit substrate; and in the fifth step, the circuit substrate is mounted on the substrate while the opposite surface side having the opening is facing the shielding plate And a sixth step of immersing the circuit substrate mounted on the substrate holder in a plating solution and performing electrolytic plating treatment to form a guide having only one opening on one side Hole.

According to this method, the multilayer printed wiring board in which the plating film is formed only on the opening surface of the via hole on one side can be stably produced at low cost without using the sub-substrate or the contamination of the electroplating bath. In addition, by setting the interval between the circuit substrate and the shielding plate to be preferably 15 mm or less, plating deposition due to a current wound on the opposite side of the opening of the common hole can be appropriately suppressed. In addition, when the gap between the circuit substrate and the shielding plate is set to 5 mm or more, particularly in the case of plating a thin circuit substrate such as a multilayer flexible printed wiring board, it is possible to suppress scratching of the circuit substrate. The contact between the curved piece and the shielding plate makes the plating solution more likely to be taken out, and it becomes difficult to wash or the like.

The invention according to claim 2 provides a method for producing a multilayer printed wiring board, comprising: a first step of forming a circuit base having three or more conductive layers and an insulating layer interposed between the conductive layers; In the second step, in the path from the conductive layer of the outermost layer of one of the circuit substrates to the conductive layer of the outermost layer of the other circuit, a non-through conductive hole of only one of the openings is formed; a step of conducting a conductive treatment on the inner wall of the common hole; and a fourth step of preparing a frame type substrate holder provided with a shielding plate, the shielding plate having a circuit substrate to be provided with the frame substrate holder One of the terminals for supplying power to the upper frame and the lower frame and the lower frame are spaced apart from each other, and the upper substrate supporting member and the support for supporting the upper end of the circuit substrate between the pair of vertical frames a lower end substrate support member at the lower end, and is in contact with the pair of left and right vertical frames and has a length extending from the upper end substrate support member to the lower end substrate support member; 5th step a side surface of the circuit substrate having the opposite surface side of the opening portion facing the shielding plate, and the two lateral end portions of the circuit substrate are brought into contact with the power supply terminal of the substrate holder; and the sixth step is performed The circuit substrate on the frame type substrate holder is immersed in a plating solution, and subjected to electrolytic plating treatment to form a via hole having an opening on only one side.

According to this method, when the circuit substrate is mounted on the frame-type holder and subjected to the plating treatment, the distance from the circuit substrate is preferably 15 mm or less, and the two lateral ends are held by the frame-type substrate. A shielding plate is provided on the opposite side of the opening of the non-through conductive hole, thereby suppressing plating deposition at both lateral ends. In addition, when the gap between the circuit substrate and the shielding plate is set to 5 mm or more, particularly in the case of plating a thin circuit substrate such as a multilayer flexible printed wiring board, it is possible to suppress scratching of the circuit substrate. When the curved piece is in contact with the shielding plate, the plating solution is taken out more and becomes difficult to be washed.

The invention of claim 3 provides a method of manufacturing a multilayer printed wiring board, comprising: a first step of forming a circuit having three or more conductive layers and an insulating layer interposed between the conductive layers In the second step, only one of the circuit substrates has an opening, and in the path from the conductive layer of the outermost layer to the outermost conductive layer, only one of the openings is formed. The conductive hole is penetrated through the common hole; in the third step, the inner wall of the common hole is electrically conductive; and in the fourth step, the circuit substrate is mounted on the plating pliers by hanging down and locking, and the plating pliers are suspended The hanging type substrate holder of the shielding plate supplies power, and the shielding plate supports the cathode rod traversely, and has the same degree of twist as the circuit substrate and the length from the upper end of the circuit substrate to the lower side than the lower end And the fifth step of immersing the plating substrate in the circuit substrate, and performing electrolytic plating treatment in a state of being adjacent to the other hanging substrate holders to form an opening having only one side Via hole.

According to this method, the circuit substrate is mounted on the hanging substrate holder that is assembled on the shielding plate to perform the plating treatment, and the circuit base is provided on the opposite side of the opening of the non-through conductive hole. The interval between the material and the shielding plate is preferably 15 mm or less, and in the electrolytic plating, the adjacent plates are adjacent to each other with the shielding plates of the substrate holders without gaps, whereby the plating deposition of the both lateral ends can be suppressed. In addition, when the gap between the circuit substrate and the shielding plate is set to 5 mm or more, particularly in the case of plating a thin circuit substrate such as a multilayer flexible printed wiring board, it is possible to suppress scratching of the circuit substrate. The contact between the curved sheet and the shielding plate causes a large amount of the plating solution to be taken out, and it becomes difficult to wash the water or the like.

The present invention provides a frame type substrate holder which is a frame type substrate holder for manufacturing a multilayer printed wiring board, and is characterized in that a shielding plate having a power supply terminal to be provided facing a circuit substrate is provided. a frame body having a gap between the upper side frame and the lower side of the vertical frame and having a gap therebetween, and an upper end substrate supporting member for supporting the upper end of the circuit substrate between the pair of vertical frames and a lower end substrate supporting the lower end And contacting the pair of vertical frames on the left and right sides and having a length extending from the upper end substrate support member to the lower end substrate support member.

According to this configuration, in the case of using the frame type substrate holder, the shielding plate is processed so as to be in contact with the upper substrate supporting member, and is extended downward from the lower end portion by 30 mm or more, preferably 60 mm or more, preferably also An auxiliary shielding plate is provided on the lower substrate support member. Further, by using the frame type substrate holder provided on the opposite side of the non-penetrating opening of the common hole during electrolytic plating, plating deposition at the lower end portion can be suppressed. However, even if the lower end of the shielding plate is made too long, the shielding effect will not be improved, so it will be considered When the dryness of the lower horizontal frame relates to the disadvantage that the amount of the plating solution is increased, it is more appropriate to set the length of the shielding plate to 120 mm or less.

The present invention provides a shielding plate that is slidably suspended from a cathode rod and attached to a hanging type substrate holder that suspends and locks a circuit substrate and supplies power, and is characterized in that: a grip portion of the shoulder of the hanging substrate holder and a protruding portion for holding the upper end of the circuit substrate and shielding, and having the same degree of rigidity as the circuit substrate and the upper end of the circuit substrate The length of the lower end is further extended.

According to this configuration, in the case of using the frameless plating apparatus, the hanging substrate holder suspended from the cathode rod is fixed to the shielding plate provided with the upper end substrate support. The circuit substrate is attached to the substrate holder so as to be in contact with the upper end substrate support. Further, the shielding plate is extended from the lower end portion of the circuit substrate downward by 30 mm or more, preferably by 60 mm or more, and by using the auxiliary shielding plate at the lower end portion of the shielding plate during electrolytic plating, the lower end portion can be suppressed. Electroplating precipitation. However, even if the lower end portion of the shielding plate is made too long, the shielding effect is not so improved. Therefore, when the weight increase and the amount of plating liquid are increased, the length of the shielding plate is set to 120 mm. The following are more appropriate.

According to the invention described in the first aspect of the invention, it is possible to inexpensively and stably produce a multilayer printed wiring board in which a plating film is formed on only one side of the via opening surface, without the contamination of the electroless plating bath. And can be Under the step of forming a complicated resist layer or the like, single-sided plating with good productivity is performed.

According to the invention described in the second aspect of the invention, when the circuit substrate is mounted on the frame type substrate holder for plating treatment, the distance between the circuit substrate and the circuit substrate is appropriately set, and the two lateral ends are in contact with the substrate holder. A shielding plate is provided on the opposite side of the opening of the non-through guide hole, thereby suppressing plating deposition at both lateral ends. Moreover, it is not necessary to carry out the treatment of the film residue after the peeling, and the cost of such auxiliary materials is not required. Moreover, there is no need to worry about the contamination of the plating bath caused by the micro-adhesive film or the heat-expandable film.

According to the invention of the third aspect of the invention, the circuit substrate is attached to the hanging substrate holder that is assembled on the shielding plate, and the plating process is performed on the opposite side of the opening of the non-through guide hole. Since the interval between the circuit substrate and the shielding plate is appropriately maintained, the shielding plates of the substrate holders are adjacent to each other with no gap between the two adjacent members during electrolytic plating, and plating deposition at both lateral ends can be suppressed. Furthermore, even if there is a distance difference between the anode and the circuit substrate due to the individual difference of the plating apparatus, there is no difference in the thickness of the electrolytic plating, and the circuit pattern of the etching process according to the photosensitive etching method can be easily made fine. Chemical. According to this, it is understood that a multilayer printed wiring board in which blind via contact of an opening having only one via hole on one side can be manufactured inexpensively and stably.

In the case where the frame type substrate holder is used in the present invention, it is possible to suppress the plating deposition of the lower end portion by using the substrate holder provided on the opposite side of the opening of the non-through guide hole during electrolytic plating. Therefore, a frame type substrate holder suitable for the manufacture of a multilayer printed wiring board can be provided.

In the case of using the frameless plating apparatus of the present invention, an appropriate size shielding plate provided with the upper end substrate support member can be fixed to the hanging type substrate holder suspended from the cathode rod. Thereby, it is possible to provide a frame type substrate holder suitable for the manufacture of a multilayer printed wiring board and a shielding plate assembled to the hanging type substrate holder.

In order to achieve a so-called simple method and to be contaminated without using an auxiliary material or an electroless plating bath, the present invention can inexpensively and stably manufacture a multilayer printed wiring board capable of forming a plating film on only one side of the via opening surface. The manufacturing method is achieved by providing a method of manufacturing a multilayer printed wiring board having the following features, the manufacturing method comprising: in the first step, forming a circuit having three or more conductive layers and an insulating layer interposed between the conductive layers a second step of forming a non-penetrating conductive hole in which only one of the openings is formed in a path from the conductive layer of the outermost layer of the circuit substrate to the outermost conductive layer of the circuit substrate; 3, the inner wall of the conductive hole is electrically conductive; and the fourth step is to prepare a substrate holder equipped with a shielding plate having a single-sided area covering the circuit substrate, and having the circuit a length in which the base material is extended downward; and in the fifth step, the circuit substrate is attached to the front side with the opposite side of the opening having the opening toward the shielding plate A substrate holder; and a sixth step, so that the circuit substrate mounted on the substrate holder is immersed in the plating solution, electrolytic plating process to form a via hole having an opening portion on one side only.

Hereinafter, several preferred embodiments of the present invention will be described in detail with reference to FIGS. 1 through 9. Further, in the respective embodiments, the common content is described in the above-described embodiments, and overlapping description will be omitted in the following embodiments.

[Example 1]

Fig. 1 is a perspective view showing a substrate in a manufacturing process of a multilayer flexible printed wiring board having a three-layer structure according to a common embodiment of the present invention. First, as shown in FIG. 1(a), a copper foil 2 having a thickness of 12 mm is formed on both surfaces of a flexible insulating base material 1 such as polyimine (here, a polyimide having a thickness of 25 μm). The double-sided copper-clad laminate 4 of the copper foil 3 is subjected to a series of steps of forming, exposing, developing, etching, and peeling off a resist layer such as a circuit pattern formed by a photosensitive etching method. Then, the copper foil 2 and the copper foil 3 of the double-sided copper-clad laminate 4 are formed into conformal masks 2a and 3a at the time of laser processing, and the inner layer circuit pattern 3b is formed on the copper foil 3.

Since the double-sided alignment at this time is performed on the flat substrate material, the expansion and contraction of the substrate material is not affected, and the positional accuracy of both sides can be easily ensured. In addition, an exposure machine with high-precision double-sided alignment can be used as needed. Further, the roughening treatment for roughening the surface may be performed as needed to improve the adhesion to the adhesive 5.

Next, a single-sided copper paste having a copper foil 7 having a thickness of 12 mm formed on one surface (here, the back surface) of a flexible insulating base material 6 (here, a polyimide having a thickness of 25 mm) such as polyimide or the like is prepared. The laminated board 8 is then punched out by the single-sided copper-clad laminate 8 to form an opening portion for the flexible cable portion, and then the punched single-sided copper-clad laminate 8 is used to form the above-mentioned The adhesive 5 of the double-sided copper-clad laminate 4 of the inner layer circuit is aligned. Further, if necessary, the single-sided copper-clad laminate 8 for punching the alignment guide or the like and the adhesive 5 for laminating the double-sided copper-clad laminate 4 on which the inner layer circuit is formed may be used. Counterpoint.

Next, as shown in FIG. 1(b), the double-sided copper-clad laminate 4 and the single-sided copper-clad laminate 8 are laminated by vacuum compression or the like via the adhesive 5. In the above steps, the circuit substrate 9 having a three-layer structure is formed. Further, as the adhesive 5, it is preferable to use a low flow type adhesive sheet or the like which causes a small amount of an adhesive to flow out. Further, in the latter step, it is not necessary to function as an adhesive for the flexible cable portion, and since flexibility is not required, a prepreg containing glass cloth can be used as the adhesive 5, but laser processing is considered. When the sex is equal, it is preferred that there is no glass cloth. Further, the thickness of the adhesive 5 can be selected from about 10 to 15 μm.

Next, as shown in FIG. 1(c), laser processing is performed using the positive masks 2a and 3a, and the copper foil 2, the copper foil 3, and the copper foil 7 which are connected to the circuit substrate 9 are formed to be non-through. Guide the general hole 10. Further, regarding the type of laser for laser processing for forming the conductive hole 10, a UV-YAG laser, a carbon dioxide laser, or a quasi-molecular laser may be selected.

Next, as shown in Fig. 1(d), the three-layer circuit substrate 9 having the conductive via 10 is subjected to a conductive treatment, and an electrolytic plating treatment of about 10 to 20 μm is applied to obtain three layers of copper foil 2 and copper. The layers of the foil 3 and the copper foil 7 are electrically connected. At this time, a so-called one-side plating treatment in which plating is not applied to the surface side having no opening (that is, the lower side of the copper foil 7 of the same diagram (d)) is performed.

Here, a method of single-sided plating treatment will be described. FIG. 2 is an end view showing a state in which three circuit boards are mounted on a substrate holder according to an embodiment of the present invention. That is, in the method of the single-sided plating treatment, as shown in FIG. 2, the circuit substrate 9 having the conductive hole 10 is fixed to the substrate holder (not shown), and the interval between the circuit substrate 9 is 15 mm or less. The shielding plate 13 is provided in such a manner as to cover one side of the circuit substrate 9. The shielding plate 13 is used to cover the opening of the circuit substrate 9 fixed by the substrate support member when the circuit substrate 9 is fixed to the substrate holder (not shown) during electrolytic plating (ie, The opposite side of the common hole 10) (that is, the back side of the circuit substrate 9). Further, as will be described in detail later, the shielding plate 13 is provided to extend downward from the lower end portion of the circuit substrate 9 by 60 mm or more.

In this way, the circuit substrate 9 fixed at the lower end by the substrate support member is set on the substrate holder, and is immersed in the plating solution for electrolytic plating treatment, as shown in FIG. 1(d), The plating film 11 is deposited on the opening surface side of the common hole 10.

Further, when the interval between the circuit substrate 9 and the shielding plate 13 in FIG. 2 is narrower than 5 mm, since the circuit substrate 9 has flexibility, the circuit substrate 9 and the shielding plate 13 are in contact with each other, and the opening of the common hole 10 is opened. The liquid renewal on the opposite side of the surface becomes difficult to perform sufficient water washing treatment. On the other hand, in the case where the interval between the circuit substrate 9 and the shielding plate 13 is more than 15 mm, the shielding effect of the upper substrate supporting member portion is weakened on the opposite side of the opening surface of the common hole 10, particularly in the circuit substrate. At the upper end portion of the electrode 9, there is a possibility that an unnecessary plating is deposited due to the electric current during the electrolytic plating treatment.

Referring back to FIG. 1, the single layer plating treatment as shown in FIG. 2 is applied to the first layer of the three-layer circuit substrate 9 as shown in FIG. 1(d), and the plating treatment is performed. A stepped via 12 is formed in the via hole 10.

Next, as shown in FIG. 1(e), the surface of the first layer which has been subjected to the plating treatment (that is, the surface of the copper foil 2) and the back surface of the third layer which is not subjected to the plating treatment (that is, The surface of the copper foil 7 is simultaneously formed by etching treatment using a photosensitive etching method to form the circuit pattern 2b and the circuit pattern 7b. At this time, in order to ensure the tenting property (that is, to prevent damage of the periphery of the resist layer due to etching), the first layer of the opening surface of the stepped via hole 12 is preferably a dry film having a thickness of 20 μm or more. Resist layer.

Further, the dry film resist for forming a fine pattern of 10 μm or less can be applied to the third layer of the copper foil 7 without considering the capping property. Further, in the case of using a liquid resist or the like, since it is not necessary to consider the cap hole property of the stepped via hole 12, the resist layers formed on the first layer and the third layer may have the same thickness.

Next, a solder resist layer or a cap layer is formed on the first layer and the third layer, and a shield layer such as a paste/film having a predetermined opening is formed as needed. Before and after this step, surface treatment such as soldering, nickel plating, gold plating, or the like is applied to the surface of the substrate as needed, and by performing the outer shape processing, three layers connected by the bottomed stepped via holes having only one opening on one side can be obtained. A plurality of flexible printed wiring boards. Further, after the multilayer flexible printed wiring board having three layers was formed by the above-described method, a high-density circuit having a wiring pitch of 60 μm was formed on the third layer.

Next, the configuration of the frame type substrate holder of the first embodiment to which the method for producing a multilayer printed wiring board of the present invention is applied will be described. Fig. 3 is a view showing a configuration of a frame type substrate holder according to a first embodiment of the present invention, wherein Fig. 3(a) is a front view, Fig. 3(b) is a bottom view, and Fig. 3(c) is an end view. Hereinafter, the configuration of the frame type substrate holder of the first embodiment will be described with reference to the full view of Fig. 3 .

The frame type substrate holder 20 in Fig. 3 is a pair of left and right vertical frames 21 provided with hooks 22 for energizing the upper portion, and is fixed by the upper side horizontal frame 23 on the upper side and the lower lateral frame 24 on the lower side. The frame. On the inner side of the upper and lower horizontal frames of the frame (that is, the upper side frame 23 and the lower side frame 24), the upper end substrate support member 25 and the lower end substrate support member 26 are respectively spanned between the left and right vertical frames 21 Mode setting. Further, on one surface of the pair of right and left frames 21 (that is, on the back side of the front view), the shielding plate 27 is attached to the upper substrate support 25, and the shielding plate 27 is in contact with the left and right vertical frames 21, and is configured. There is a length extending from the lower substrate support member 26 downward. Further, in the lower substrate support member 26, the auxiliary shielding plate 28 is mounted in a direction parallel to the shielding plate 27.

3, the pair of vertical frames 21 shown in the front view are respectively constituted by the support 21a and the substrate pressing plate 21b as shown in the bottom view. Further, the substrate pressing plate 21b is attached to the support 21a and the hinge 21c so as to be openable and closable. Further, the circuit substrate 29 is attached in such a manner as to be inserted by the pillar 21a and the substrate pressing plate 21b.

Further, although not shown in the drawings, a power supply terminal for supplying power to the circuit substrate 29 is provided in a portion of the circuit substrate 29 on which the pillar 21a and the substrate pressing plate 21b are held. The connection terminal of the power supply terminal is electrically connected to the hook 22 of the upper portion of the frame type substrate holder 20 via a wire or the like. That is, the hook 22 is in contact with the cathode rod of the upper portion of the plating apparatus (not shown) to supply power to the power supply terminal of the frame type substrate holder 20. In addition, in order to adjust the thickness of the plating in the surface of the circuit board 29, a plate-shaped shield as described in Patent Document 3 of the same applicant may be attached to the substrate pressing plate 21b.

Further, the upper lateral frame 23 for the upper upper substrate support 25 and the lower lateral frame 24 for the lower lower substrate support 26 are attached to the left and right vertical frames 21, respectively, and the left and right vertical frames 21 are attached. It is maintained at a predetermined interval while serving as a substrate support for supporting the upper and lower sides of the circuit substrate 29.

Further, in the frame type substrate holder 20, the shielding plate 27 is provided at a position covering one surface of the circuit substrate 29. The single side of the circuit substrate 29 in the present embodiment means the back side of the mounted circuit board 29 (that is, the back side of the front view of Fig. 3). Further, the shielding plate 27 is disposed at a position of 5 to 15 mm from the surface of the circuit substrate 29.

Further, as shown in the bottom view, the shielding plate 27 is in contact with the pillar 21a left and right without a gap. Further, the upper portion of the shielding plate 27 and the upper end substrate supporting member 25 are slightly provided with a gap, but as shown in the end face view of the A-A', if the upper portion of the shielding plate 27 and the upper end substrate supporting member 25 are joined without a gap In the case where it is necessary to provide a passage for pumping air to the upper substrate support member 25.

Further, as shown in the end face view of A-A', the lower end of the shield plate 27 is extended from the lower end substrate support member 26 to the lower side. Its extended length is set to be about 90 mm. Further, when the shielding plate 27 is extended from the circuit substrate 29 downward by less than 30 mm, the shielding effect is weakened, and the opposite side of the opening surface of the common hole, particularly at the lower end portion of the circuit substrate 29, may be electrolytically plated. When the current is bypassed, unnecessary plating is deposited. On the other hand, when the shielding plate 27 is extended by 120 mm or more from the circuit substrate 29, the amount of the plating solution may be caused by interference with the lower lateral frame 24 and the liquid adhering to the shielding plate 27. Increase the disadvantages.

Therefore, in order to enhance the shielding effect on the winding current of the lower side, the lower portion of the shielding plate 27 is provided with an inclination toward the front side. However, it is necessary to provide a gap between the shielding plate 27 and the lower substrate supporting member 26 in advance in a gap to the extent that the discharge can be quickly performed when the plating bath or the washing tank is raised.

Further, an auxiliary shielding plate 28 is attached to the lower substrate support member 26. The height of this auxiliary shielding plate 28 is set to 20 mm. Further, although not shown, it is necessary to provide a passage for discharging the lower substrate support 26 in advance so that the plating solution or the washing water remaining between the circuit substrate 29 and the auxiliary shielding plate 28 is appropriately discharged.

[Embodiment 2]

Fig. 4 is a view showing a configuration of a frame type substrate holder according to a second embodiment of the present invention, wherein Fig. 4(a) is a front view, Fig. 4(b) is a bottom view, and Fig. 4(c) is an end view. Hereinafter, the configuration of the frame type substrate holder of the second embodiment will be described with reference to the full view of Fig. 4 . In the frame type substrate holder 30, the pair of left and right vertical frames 31 and 31' including the power supply terminals are fixed by the upper side frame 33 and the lower side frame 34. body.

4 is different from FIG. 3 in that a sliding mechanism is provided to change the interval between the upper horizontal frame 33 and the lower horizontal frame 34. Therefore, the shielding plates 37, 37' are divided into right and left sides, and are respectively attached to the left and right vertical frames 31, 31'. Further, the shielding plates 37 and 37' are in contact with the left and right vertical frames 31 and 31', and are formed to have a length extending downward from the lower substrate supporting member 36.

That is, the shield plates 37, 37' are configured to be slidable over each other, and a slight gap is formed between the upper substrate support member 35 and the upper substrate support member 35. Therefore, the upper side of the shielding effect shielding plates 37, 37' is also configured to have a length extending beyond the upper end substrate supporting member 35, and the portion extending upward is inclined toward the front side. Further, auxiliary shielding plates 38, 38' are attached to the lower substrate support 36 in the same manner.

[Example 3]

Fig. 5 is a view showing a configuration of a frame type substrate holder according to a third embodiment of the present invention, wherein Fig. 5(a) is a front view, Fig. 5(b) is a bottom view, Fig. 5(c) is an end view, and Fig. 5; (d) is a partial enlarged view. Hereinafter, the configuration of the frame type substrate holder of the third embodiment will be described with reference to the full view of Fig. 5 . Similarly to the above-described FIG. 3, the frame type substrate holder 40 is such that the pair of left and right vertical frames 41 provided with the power supply terminals are fixed by the upper lateral frame 43 and the lower lateral frame 44 to form a fixed frame. The single-sided shielding plate 47 of the casing is attached to the upper end substrate supporting member 45, and the shielding plate 47 is in contact with the right and left vertical frames 41, and is formed to have a length extending downward from the lower end substrate supporting member 46. Further, an auxiliary shielding plate 48 is provided on the lower substrate support member 46.

The difference between FIG. 5 and FIG. 3 is that the shielding plate 47 is not disposed to be inclined toward the front side, but extends straight, and the auxiliary shielding plate 48 is opened and closed freely at the lower end of the lower end substrate support 46. Further, the auxiliary shielding plate 48 is made of a material having a lighter specific gravity than the plating solution. Therefore, as shown in a partially enlarged view, when the auxiliary shielding plate 48 is immersed in the plating solution, the gap between the lower substrate support member 46 and the shielding plate 47 is blocked by buoyancy, and the shielding plate side facing the circuit substrate 49 is prevented. The plating spread. Further, when the substrate holder 40 is raised from the liquid surface, the auxiliary shielding plate 48 is naturally released by gravity, and the plating solution immersed between the circuit substrate 49 and the shielding plate 47 can be smoothly drained. Thereby, the plating liquid is not stagnated on the lower substrate support member 46 through the auxiliary shielding plate 48, and since the inclination for lifting the shielding effect is not required to be provided on the shielding plate 47, the amount of plating solution can be further reduced.

Next, the configuration of several embodiments of the shielding plate in the hanging type substrate holder will be described with reference to Figs. 6 to 9 .

[Example 4]

Fig. 6 is a view showing a configuration of a hanging type substrate holder according to a fourth embodiment of the present invention, wherein Fig. 6(a) is a front view, Fig. 6(b) is a bottom view, and Fig. 6(c) is A-A' The end view and Fig. 6(d) are B-B' end views. Hereinafter, the configuration of the hanging type substrate holder of the fourth embodiment will be described with reference to the full view of Fig. 6 . That is, Fig. 6 is a structural view showing an embodiment of a shielding plate assembled on the hanging type substrate holder according to the present invention. The hanging type substrate holder 50 which is slidably suspended in a cathode rod (not shown) in FIG. 6 is a plating pliers 51 which is suspended from the circuit substrate 59 and is used for power supply, and is used for lifting The hanging substrate holder 50 is constructed by hooking a hook 52 of a cathode rod (not shown) and a shoulder portion 53 connecting the plating pliers 51 and the hook 52.

The shielding plate 57 is assembled to the hanging substrate holder 50 and has an area covering one surface of the circuit substrate 59. The shielding plate 57 has the same degree of twist as the circuit substrate 59, and has a length extending downward from the lower end of the circuit substrate 59. In the present embodiment, the grip portion 57a of the shield plate 57 is formed in a groove shape in which the shoulder portion 53 is fitted, and the shutter portion 57 is not swayed back and forth by the grip portion 57a being hung on the shoulder portion 53. Further, the shielding plate 57 is provided with a protruding portion 57b for holding the upper end of the circuit substrate 59 and shielding the current drawn from the upper side. Moreover, in order to increase the shielding effect, the shielding plate 57 is oriented downward from the lower end of the circuit substrate 59, and an inclined portion is provided toward the circuit substrate 59 side.

The shielding plate 57 is mounted at a position 5 to 15 mm from the surface of the circuit substrate 59. The lower end of the shielding plate 57 is extended from the lower end of the circuit substrate 59 to the lower side. Its extended length is set to 90mm. Further, when the length of the shielding plate 57 extending downward from the circuit substrate 59 is shorter than 30 mm, the shielding effect is weakened, and on the opposite side of the opening surface of the general-purpose hole 10 (refer to FIG. 1(c)), in particular At the lower end portion of the circuit substrate 59, there is a possibility that an unnecessary plating is deposited due to the winding of the current during electrolytic plating. On the other hand, when the shielding plate 57 is extended downward from the circuit substrate 59 by more than 120 mm, the weight of the shielding plate 57 is increased, the whole is inclined, and the load is applied to the holding portion 57a, and the plating liquid is caused by the adhered liquid. The shortcomings such as increased output.

Further, the lower end portion of the circuit substrate 59 is attached with a lower end substrate support 56, and the lower end substrate support 56 has an auxiliary shielding plate 58. The auxiliary shielding plate 58 is erected upward from the lower end of the circuit substrate 59, and serves to shield the current from the lower side. Further, although not shown, the lower substrate support 56 is provided with a passage for draining in advance, so that the plating solution or the washing water remaining between the circuit substrate 59 and the auxiliary shielding plate 58 is appropriately discharged.

[Example 5]

Fig. 7 is a view showing the configuration of a hanging type substrate holder according to a fifth embodiment of the present invention, wherein Fig. 7(a) is a front view, Fig. 7(b) is a bottom view, and Fig. 7(c) is A-A'. The end view and Fig. 7(d) are B-B' end views. Hereinafter, the configuration of the hanging type substrate holder of the fifth embodiment will be described with reference to the full view of Fig. 7 . In the same manner as in FIG. 6, the shielding plate 67 includes a holding portion 67a that is fitted into the shoulder portion 63 of the hanging substrate holder 60, and a current for holding the upper end of the circuit substrate 69 and shielding the current from the upper side. Projection portion 67b.

7 and FIG. 6 differ in that the shielding plate 67 extends downward from the lower end of the circuit substrate 69, but the inclined portion and the auxiliary shielding plate 68 provided on the lower substrate supporting member 66 are supported from the lower substrate. The member 66 protrudes toward the shielding plate and is bent downward.

The auxiliary shielding plate 68 prevents the plating solution from being wound from the lower side toward the surface of the circuit substrate 69 opposed to the shielding plate 67 side, and serves as a role for maintaining the distance of the shielding plate 67 at a predetermined interval, even in the case of In the plating solution, the circuit substrate 69 is subjected to the pressure generated by the liquid flow, and the circuit substrate 69 and the shielding plate 67 are prevented from coming into contact with each other. Further, when the hanging substrate holder 60 is lifted from the liquid surface, the auxiliary shielding plate 68 is bent downward, so that the interval between the auxiliary shielding plate 68 and the shielding plate 67 is changed by the flow of the plating liquid, and the opening can be smoothly performed. Drain. Moreover, the upper substrate support member 66 is also prevented from stagnating by the plating liquid through the curved auxiliary shielding plate 68. Thereby, since it is not necessary to provide the inclination for lifting the shielding effect on the shielding plate 67, the amount of the plating solution can be further reduced.

[Embodiment 6]

Fig. 8 is a view showing the configuration of a hanging type substrate holder according to a sixth embodiment of the present invention, wherein Fig. 8(a) is a front view, Fig. 8(b) is a bottom view, and Fig. 8(c) is A-A' The end view, Fig. 8(d) are B-B' end views, and Fig. 8(e) are partial enlarged views. Hereinafter, the configuration of the hanging type substrate holder of the sixth embodiment will be described with reference to the full view of Fig. 8 .

In the same manner as in Fig. 7, the shielding plate 77 has a holding portion 77a in which the shoulder portion 73 of the hanging type substrate holder 70 is fitted, and a current for holding the upper end of the circuit substrate 79 and shielding the current from the upper side. The protruding portion 77b, the portion of the shielding plate 77 that extends downward from the lower end of the circuit substrate 79 is not inclined.

The difference between Fig. 8 and Fig. 7 is that the auxiliary shielding plate 78 provided at the lower end substrate support member 76 is provided to be openable and closable. That is, similarly to FIG. 5 described above, the auxiliary shielding plate 78 is formed of a material having a lighter specific gravity than the plating solution. Therefore, when immersed in the plating solution as shown in FIG. 8(e), the auxiliary shielding plate 78 is blocked by the buoyancy to block the gap between the lower substrate support member 66 and the shielding plate 67, thereby preventing plating from being applied to the circuit substrate 79. The surface of the side of the shielding plate 77 spreads.

Further, when the hanging substrate holder 70 is raised from the liquid surface, the gap between the lower substrate support 66 and the shielding plate 67 is naturally released by the gravity of the auxiliary shielding plate 78, so that the substrate can be smoothly immersed in the circuit. The plating solution between the material 79 and the shielding plate 77 is drained. Further, since the gap between the shield plate 77 and the auxiliary shield plate 78 is opened larger than in the case of Fig. 7, the discharge of the plating solution is performed more smoothly, so that the amount of the plating solution can be further reduced.

[Embodiment 7]

Fig. 9 is a view showing a configuration of a hanging type substrate holder according to a seventh embodiment of the present invention, wherein Fig. 9(a) is a front view, Fig. 9(b) is a bottom view, and Fig. 9(c) is A-A' The end view and Fig. 9(d) are B-B' end views. Hereinafter, the configuration of the hanging type substrate holder of the seventh embodiment will be described with reference to the full view of Fig. 9 . 9 is the same as FIG. 6, the shielding plate 87 has a holding portion 87a that is fitted into the shoulder portion 83 of the hanging type substrate holder 80, and a current for holding the upper end of the circuit substrate 89 and shielding the current from the upper side. The protruding portion 87b is a portion of the shielding plate 87 that is lower than the lower end of the circuit substrate 89, and extends vertically without tilting toward the circuit substrate 89 side.

9 and FIG. 6 differ in that the auxiliary shielding plate 88 is installed between the shielding plate 87 and the lower end position of the circuit substrate 89, and facing the circuit substrate 89, without being mounted with the lower end substrate support. The direction is convexly bent downwards. The auxiliary shielding plate 88 prevents plating from spreading from the lower surface toward the surface of the circuit substrate 89 on the side of the shielding plate 87, and serves to maintain the interval between the circuit substrate 89 and the shielding plate 87.

Further, when the hanging substrate holder 80 is raised from the liquid surface, the circuit substrate 87 is deflected by the flow of the plating solution, and the distance between the substrate base 87 and the auxiliary shielding plate 88 is widened, so that the liquid can be smoothly discharged. . By attaching the auxiliary shielding plate 88 to the shielding plate 87 in this way, it is possible to manufacture the multilayer printed wiring board more efficiently without consuming the need to attach the lower substrate supporting member to the circuit substrate 87.

As described above, according to the method for producing a plurality of printed wiring boards of the present invention, it is possible to perform single-sided plating with good productivity without performing complicated steps such as formation of a resist layer. Moreover, it is not necessary to carry out the treatment of the film residue after the peeling, and the cost of such auxiliary materials is not required. In addition, there is no need to worry about the contamination of the plating bath caused by such micro-adhesive films or heat-expandable films. Further, even if a difference in distance between the anode and the circuit material occurs due to the individual difference of the plating apparatus, the thickness difference of the electrolytic plating does not occur, and the circuit pattern formed by the etching processing by the photosensitive etching method is easily followed. Be fine. According to the above, it is possible to provide a method of manufacturing a multilayer printed wiring board in which blind vias having only one opening on one side are inexpensively and stably manufactured, and a frame type substrate holder suitable for manufacturing the multilayer printed wiring board, And a shielding plate combined with the hanging substrate holder.

As described above, although several embodiments of the present invention have been described, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention, and the present invention can of course be adapted to the changer. .

[Industrial value]

According to the method for manufacturing a multilayer printed wiring board and the substrate holder and the shielding plate of the present invention, since the single-sided plating treatment can be performed on the substrate in a state of good productivity, the semiconductor mounting substrate can be effectively utilized. Manufacturing equipment, etc.

1. . . Flexible insulating substrate

2. . . Copper foil

2a. . . Orthotropic mask

2b. . . Circuit pattern

3. . . Copper foil

3a. . . Orthotropic mask

3b. . . Circuit pattern

4. . . Double-sided copper laminate

5. . . Follower

6. . . Flexible insulating substrate

7. . . Copper foil

7b. . . Circuit pattern

8. . . Single-sided copper laminate

9. . . Circuit substrate

10. . . Universal hole

11. . . Plating layer (plating film)

12. . . Stepped via

13. . . Masking board

20, 30, 40. . . Frame type substrate holder

21, 31, 31', 41. . . Vertical frame

21a, 31a, 31a', 41a. . . pillar

21b, 31b, 31b', 41b. . . Substrate pressing plate

21c, 31c, 41c. . . Hinge

22, 32, 42. . . hook

23, 33, 43. . . Upper side frame

24, 34, 44. . . Lower side frame

25, 35, 45. . . Upper substrate support

26, 36, 46. . . Lower substrate support

27, 37, 37', 47. . . Masking board

28, 38, 38', 48. . . Auxiliary shielding plate

29, 39, 49. . . Circuit substrate

50, 60, 70, 80. . . Hanging type substrate holder

51, 61, 71, 81. . . Plating pliers

52, 62, 72, 82. . . hook

53, 63, 73, 83. . . Shoulder

56, 66, 76. . . Lower substrate support

57, 67, 77, 87. . . Masking board

57a, 67a, 77a, 87a. . . Holding department

57b, 67b, 77b, 87b. . . Protruding

58, 68, 78, 88. . . Auxiliary shielding plate

59, 69, 79, 89. . . Circuit substrate

[Fig. 1 (a) to Fig. 1 (e)] is a substrate end view showing a manufacturing procedure of a multilayer flexible printed wiring board having a three-layer structure in a common example of the present invention.

Fig. 2 is a configuration diagram of an end surface in a state in which a three-layer circuit substrate is mounted on a substrate holder according to an embodiment of the present invention.

3(a) to 3(c) are diagrams showing a configuration of a frame type substrate holder according to a first embodiment of the present invention, wherein (a) is a front view, (b) is a bottom view, and (c) is A. -A' end view.

4(a) to 4(c) are views showing the configuration of a frame type substrate holder according to a second embodiment of the present invention, wherein (a) is a front view, (b) is a bottom view, and (c) is A. -A' end view.

5(a) to 5(d) are diagrams showing a configuration of a frame type substrate holder according to a third embodiment of the present invention, wherein (a) is a front view, (b) is a bottom view, and (c) is A. The -A' end view and (d) are partial enlarged views.

6(a) to 6(d) are diagrams showing a configuration of a hanging type substrate holder according to a fourth embodiment of the present invention, wherein (a) is a front view, (b) is a bottom view, and (c) is a The A-A' end view and (d) are B-B' end views.

7(a) to 7(d) are diagrams showing a configuration of a hanging type substrate holder according to a fifth embodiment of the present invention, wherein (a) is a front view, (b) is a bottom view, and (c) is a The A-A' end view and (d) are B-B' end views.

8(a) to 8(e) are diagrams showing a configuration of a hanging type substrate holder according to a sixth embodiment of the present invention, wherein (a) is a front view, (b) is a bottom view, and (c) is a The A-A' end view, (d) is the B-B' end view, and (e) is a partial enlarged view.

9(a) to 9(d) are diagrams showing a configuration of a hanging type substrate holder according to a seventh embodiment of the present invention, wherein (a) is a front view, (b) is a bottom view, and (c) is a The A-A' end view and (d) are B-B' end views.

1. . . Flexible insulating substrate

2. . . Copper foil

3. . . Copper foil

4. . . Double-sided copper laminate

5. . . Follower

6. . . Flexible insulating substrate

7. . . Copper foil

8. . . Single-sided copper laminate

9. . . Circuit substrate

10. . . Universal hole

13. . . Masking board

Claims (3)

A method of manufacturing a multilayer printed wiring board, comprising: forming a circuit substrate having three or more conductive layers and an insulating layer interposed between the conductive layers; and a second step of: forming the circuit substrate The conductive layer of the outermost layer of one of the materials reaches the path of the conductive layer of the outermost layer of the other material, and forms a non-through conductive common hole of only one of the openings; and a third step of performing the inner wall of the conductive common hole a fourth step of preparing a substrate holder equipped with a shielding plate having a surface covering one surface of the circuit substrate and having a length extending downward from the circuit substrate; The circuit board is attached to the substrate holder with the opposite surface side of the opening having the opening toward the shielding plate; and the sixth step of immersing the circuit substrate attached to the substrate holder in the plating The liquid is subjected to electrolytic plating treatment to form a via hole having only one opening on one side. A method of manufacturing a multilayer printed wiring board, comprising: forming a circuit substrate having three or more conductive layers and an insulating layer interposed between the conductive layers; and a second step of: forming the circuit substrate The conductive layer of the outermost layer of one of the materials reaches the path of the conductive layer of the outermost layer of the other material, and forms a non-through conductive common hole of only one of the openings; and a third step of performing the inner wall of the conductive common hole The fourth step of preparing a frame type substrate holder provided with a shielding plate having one of power supply terminals provided for supplying power to the circuit substrate of the frame type substrate holder to the vertical frame a frame and a lower frame which are spaced apart from each other and have a frame body having an upper end substrate supporting member for supporting an upper end of the circuit substrate between the pair of vertical frames and a lower end substrate supporting member for supporting a lower end, wherein the shielding plate and the shielding plate are The pair of left and right vertical frames are in contact with each other and have a length extending from the upper end substrate support member to the lower end substrate support member; and in the fifth step, the one having the opening portion a second side end portion of the circuit substrate is mounted in contact with the power supply terminal of the substrate holder, and a sixth step of causing the circuit to be mounted on the frame type substrate holder The substrate is immersed in the plating solution, and subjected to electrolytic plating treatment to form via holes having openings on only one side. A method of manufacturing a multilayer printed wiring board, comprising: a first step of forming a circuit substrate having three or more conductive layers and an insulating layer interposed between the conductive layers; and a second step of only the circuit substrate One of the openings has an opening, and in the path from the conductive layer of the outermost layer to the outermost conductive layer of the other one, a non-through conductive hole of only one of the openings is formed; and the third step is The inner wall of the common hole is electrically conductively processed; in the fourth step, the circuit substrate is mounted on the plating pliers by hanging down and locking, and the plating pliers supply power to the hanging type substrate holder on which the shielding plate is suspended. The shielding plate is slidably suspended from the cathode rod and has And the length of the circuit substrate is equal to the length from the upper end of the circuit substrate to a length lower than the lower end; and in the fifth step, the circuit substrate is immersed in the plating solution to be adjacent to the other hanging substrate holder The electrolytic plating treatment is performed in a state in which a via hole having an opening on only one side is formed.