JP2006318964A - Wiring board, manufacturing method thereof, and electrooptical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a wiring board capable of forming a multilayer double-sided interconnection board 20 at low costs. <P>SOLUTION: There are provided a process for forming a multilayer wiring structure 10 in which first and connection terminals 16b, 16t are provided at the side of a temporary substrate 13 and a side opposite to the temporary substrate 13, respectively, on the surface of the temporary substrate 13; and a process for removing the temporary substrate 13 to expose the first connection terminal 16b to the rear of the multilayer wiring structure 10. The multilayer wiring structure 10 is formed by using a droplet discharge method. Preferably, the second and first connection terminals 16t, 16b are composed of an Au material. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a wiring board, a wiring board, and an electro-optical device.

  A wiring board is used in various electronic devices. With downsizing of electronic devices, downsizing of wiring boards is required. In order to reduce the size of the wiring board, it is important to increase the definition of the wiring and increase the number of layers. In order to increase the number of wirings, the wirings are stacked and disposed via an interlayer insulating film, and the upper and lower wirings are conductively connected by conductive posts.

  In addition, in order to reduce the size of the electronic device, it is necessary to realize space saving by increasing the degree of freedom of mounting electronic components on the wiring board and the degree of freedom of mounting of the wiring board on the electro-optical device and the like. In order to increase mounting flexibility, it is desirable to provide mounting terminals on both sides of the multilayer wiring board.

Therefore, Patent Document 1 proposes a method for manufacturing a multilayer substrate having electrodes on both sides. In this method, a conductor pattern is formed on one surface of a resin film, a laser beam is irradiated from the other surface of the resin film to form a bottomed via hole having the conductor pattern as a bottom surface, and a conductive paste is filled in the via hole. A single-sided conductor pattern film is formed. A multilayer substrate having electrodes on both sides is manufactured by laminating a plurality of single-sided conductor pattern films and the like.
JP 2003-86948 A

  As described above, in the method for manufacturing a multilayer double-sided wiring board disclosed in Patent Document 1, it is necessary to perform via hole drilling processing (laser via processing) using a laser. In addition, since the number of laser via processing increases in proportion to both the number of wiring layers and the number of connection terminals, the manufacturing process becomes complicated and a large manufacturing cost is required. In laser via processing, it is difficult to form a via hole having a diameter of 50 μm or less, which hinders narrowing of the wiring pitch, and there are still problems in hole position accuracy and post-process alignment accuracy.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a method for manufacturing a wiring board capable of forming a multilayer double-sided wiring board at a low cost. It is another object of the present invention to provide a wiring board and an electro-optical device that can be miniaturized.

In order to achieve the above object, a method for manufacturing a wiring board according to the present invention uses a droplet discharge method to form a first connection terminal, a conductive member, an insulating layer, and a first layer on the surface of a temporary substrate containing a first material. 2 connection layers are formed, and the temporary substrate is removed.
Moreover, you may provide the process of forming a wiring, a 2nd conduction | electrical_connection member, and a 2nd insulating layer between the said insulating layer and the said 2nd connection layer.
According to this configuration, a via hole drilling process using a laser is not required. Therefore, a multilayer double-sided wiring board can be formed at low cost.

According to another aspect of the present invention, there is provided a method for manufacturing a wiring substrate, comprising: forming a multilayer wiring structure having a second connection terminal on the opposite side of the temporary substrate on the surface of the temporary substrate including the first material; And removing the temporary substrate to form a first connection terminal on the other surface of the multilayer wiring structure.
According to this configuration, since the first connection terminal is formed by removing the temporary base, there is no need for via hole drilling with a laser. Therefore, a multilayer double-sided wiring board can be formed at low cost.
In addition, since the multilayer wiring structure and connection terminals can be formed on the surface of the hard temporary substrate, the patterning of the wiring and connection terminals can be performed compared to the case where the multilayer wiring structure and connection terminals are formed on the surface of the resin layer or the like. The accuracy can be improved. Therefore, the pitch of the wiring and the connection terminal can be reduced.

According to another aspect of the present invention, there is provided a method for manufacturing a wiring board, comprising: a first connection terminal on a temporary substrate side on a surface of a temporary substrate including a first material; and a second connection terminal on the opposite side of the temporary substrate. And a step of removing the temporary base to expose the first connection terminal.
According to this configuration, a multilayer double-sided wiring board can be formed particularly at low cost.

The first connection terminal is preferably formed by patterning a mask material on the surface of the temporary substrate made of a conductive material and performing electrolytic plating.
According to this configuration, since the mask material is patterned on the surface of the hard temporary substrate, the patterning accuracy can be improved as compared with the case where the mask material is patterned on the surface of the resin layer or the like. In addition, since the first connection terminals are formed by plating, the pitch of the first connection terminals can be narrowed compared to the conventional subtractive method (etching method). Further, since the temporary base is made of a conductive material and the first connection terminals are formed by the electrolytic plating method, the first connection terminals can be easily formed in a shorter time than the electroless plating method.

Moreover, it is desirable that the first connection terminal and the second connection terminal are made of a material whose main component is gold.
According to this configuration, since the connection terminal exposed to the outside is made of a stable gold material, the occurrence of migration can be prevented.

The formation of the multilayer wiring structure is preferably performed using a droplet discharge method.
According to this configuration, photolithography can be reduced and the manufacturing process can be simplified. In addition, since the material use efficiency is increased, a multilayer double-sided wiring board can be formed at low cost. Furthermore, the wiring and the conductive posts can be formed with high accuracy at predetermined positions.

The temporary substrate is preferably formed by forming a separation layer made of the first material on the surface of the substrate made of the second material.
According to this configuration, the consumption amount of the first material can be reduced, the removal time of the temporary substrate can be shortened, and the substrate can be reused. Therefore, a multilayer double-sided wiring board can be formed at low cost.

In the step of forming the multilayer wiring structure, it is preferable that a plurality of the multilayer wiring structures are spaced from each other on the surface of the temporary substrate, and the temporary substrate is removed to obtain a plurality of wiring boards.
According to this configuration, a plurality of multilayer double-sided wiring boards can be formed simultaneously.

The step of removing the temporary substrate is preferably performed by etching the temporary substrate using an etchant having an etching rate for the first material higher than that for the constituent material of the connection terminal.
According to this configuration, it is possible to remove only the temporary substrate while leaving the connection terminals. Therefore, a multilayer double-sided wiring board can be formed at low cost.

Preferably, the first material is mainly composed of copper, the connection terminal is mainly composed of gold, and the etchant is mainly composed of ferric chloride.
In etching using ferric chloride as an etchant, the etching rate for copper is higher than the etching rate for gold. Therefore, it is possible to remove only the temporary substrate while leaving the connection terminals, and a multilayer double-sided wiring board can be formed at low cost.

On the other hand, the wiring board according to the present invention is manufactured using the above-described method for manufacturing a wiring board.
According to this configuration, a low-cost multilayer double-sided wiring board can be provided.

On the other hand, an electro-optical device according to the present invention includes the wiring board described above.
According to this configuration, it is possible to provide a low-cost electro-optical device including a low-cost multilayer double-sided wiring board.

  Embodiments of the present invention will be described below with reference to the drawings. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size.

[Wiring board]
First, the multilayer double-sided wiring board according to the first embodiment of the present invention will be described with reference to the side sectional view of FIG. Note that the multilayer wiring pattern described below is merely an example, and other multilayer wiring patterns can be employed. The multilayer double-sided wiring board 20 according to the first embodiment is configured by laminating a plurality of wiring layers 12 (12a, 12b, 12c, 12d). Each wiring layer 12 includes a wiring 16, a conductive post 17, and an interlayer insulating film 18.

  The wiring 16 is formed in a predetermined pattern using a conductive material such as Ag. The line × space of the wiring 16 is miniaturized to, for example, about 30 μm × 30 μm by adopting a droplet discharge method described later. An interlayer insulating film 18 is formed so as to cover the wiring 16. The interlayer insulating film 18 is made of an electrically insulating material obtained by mixing an ultraviolet curable resin such as acrylic and a thermosetting resin such as epoxy. A conductive post (conductive member) 17 is erected so as to penetrate the interlayer insulating film 18. The conductive post 17 is formed in a cylindrical shape or the like by the same conductive material such as Ag as the wiring 16 and is connected to the wiring 16. For example, the thickness of the wiring 16 is about 2 μm, and the height of the conductive post 17 is about 8 μm.

  The wiring layer 12 is constituted by the wiring 16, the conductive post 17 and the interlayer insulating film 18 described above. It is also possible to configure the wiring layer 12 by mounting an electronic component (not shown) on the wiring 16 and forming the interlayer insulating film 18 so as to cover the wiring 16 and the electronic component. A plurality of wiring layers 12 are stacked to form a multilayer wiring structure 10. The wiring 16 of each wiring layer 12 is conductively connected through a conductive post 17. In FIG. 3B, the four wiring layers 12 (12a, 12b, 12c, 12d) are laminated, but the number of laminated layers may be other than this.

  And the wiring of the 1st wiring layer 12a of a lower end is exposed outside, and the 1st connection terminal 16b is comprised in the back surface of the multilayer wiring structure 10. FIG. In addition, a second connection terminal (second connection layer) 16t is formed on the surface of the multilayer wiring structure 10 in a state of being connected to the conduction post of the upper fourth wiring layer 12d. As described above, the multilayer double-sided wiring board 20 of the present embodiment includes the connection terminals 16b and 16t on both sides. The first connection terminal 16b and the second connection terminal 16t exposed to the outside are preferably made of Au material. This is because if the connection terminals 16b and 16t are made of Ag material in the same manner as the wiring 16 in the intermediate second wiring layer 12b and the third wiring layer 12c, migration occurs due to adhesion of moisture. Note that the first connection terminal 16b may be formed by configuring the wiring in the first wiring layer 12a at the lower end with an Ag material or the like and applying Au plating or the like to the surface thereof.

[Method of manufacturing a wiring board]
Next, the manufacturing method of the wiring board according to the first embodiment will be described with reference to FIGS. 1 to 3 are process diagrams of a method of manufacturing a wiring board according to the first embodiment. The method for manufacturing the multilayer double-sided wiring board 20 according to the present embodiment includes a first connection terminal 16b on the temporary substrate 13 side on the surface of the temporary substrate (temporary substrate) 13, and a second connection terminal 16t on the opposite side of the temporary substrate 13. And a step of removing the temporary substrate 13 to expose the first connection terminals 16b on the back surface of the multilayer wiring structure 10.

First, as shown in FIG. 1A, a temporary substrate (temporary substrate) 13 is prepared. The material of the temporary substrate 13 will be described later. Next, a resist (mask material) 14 is applied to the surface of the temporary substrate 13, and the opening 16p is patterned at the position where the first connection terminal is formed by photolithography.
Next, as shown in FIG. 1B, first connection terminals 16 b are formed on the surface of the temporary substrate 13. Specifically, the first connection terminal 16b having a predetermined pattern is formed in the opening 16p of the resist 14 by performing electrolytic plating using the temporary substrate 13 made of a conductive material as an electrode.
Next, as shown in FIG. 1C, the resist is removed from the surface of the temporary substrate 13. As a method for forming the first connection terminal 16b, a droplet discharge method may be employed instead of the electrolytic plating method described above.

  Next, as shown in FIG. 2A, a conductive post 17 is formed. The conductive post 17 is formed by a droplet discharge method using a droplet discharge device. Therefore, first, a dispersion is prepared in which conductive fine particles, which are the material for forming the conductive posts 17, are dispersed in a dispersion medium. Silver is preferably used as the conductive fine particles. In addition, fine particles of conductive polymer or superconductor can be used in addition to metal fine particles containing any of gold, copper, palladium, and nickel. As the dispersion medium, water, alcohols, hydrocarbon compounds, and ether compounds are preferable in terms of the dispersibility of the fine particles, the stability of the dispersion, and the ease of application to the droplet discharge method. Preferred examples of the dispersion medium include water and hydrocarbon compounds. These dispersion media may be used alone or in combination of two or more.

  Next, droplets of the dispersion liquid are ejected from a droplet ejection head and dropped onto a place where a conductive post is to be formed. Note that in order to form the conductive post at a considerable height, it is necessary to eject and deposit a large number of droplets, but even if a large number of droplets are ejected at once, the droplets spread and get wet. Therefore, the droplets are deposited by repeatedly discharging and temporarily drying the droplets. This temporary drying is performed so that at least the surface of the discharged droplets is dried. As a specific method, it is desirable to employ dry air blowing, infrared irradiation, or the like. And finally, the conduction post 17 is formed by performing the main baking. This main baking is performed, for example, by placing the temporary substrate 13 on a hot plate at 200 ° C. and heating the deposited droplets for about 1 hour.

  Next, as shown in FIG. 2B, an interlayer insulating film 18 is formed so as to cover the first connection terminals 16b. The interlayer insulating film 18 is also formed by a droplet discharge method using a droplet discharge device. Specifically, first, a resin material that is a material for forming the interlayer insulating film 18 is discharged from a droplet discharge head. At that time, the resin material is discharged so as to cover the side surface of the conductive post 17 and the surface of the first connection terminal while exposing the upper end surface of the conductive post 17. Then, the interlayer insulating film 18 is formed by curing the discharged resin material by irradiating UV. Thus, the first wiring layer 12a is formed.

  Next, as shown in FIG. 2C, the wiring 16 of the second wiring layer 12b is formed on the surface of the first wiring layer 12a. The wiring 16 is also formed by a droplet discharge method using a droplet discharge device. Here, conductive fine particles, which are wiring forming materials, are dispersed in a dispersion medium and discharged from a droplet discharge head. Specifically, it is possible to discharge the same dispersion liquid used for forming a conductive post. . And the wiring 16 is formed by performing this baking similarly to the case where a conduction post is formed. Further, if conductive posts and interlayer insulating films are formed in the same manner as the first wiring layer 12a, the second wiring layer 12b is laminated. Similarly, the third wiring layer 12c and the fourth wiring layer 12d are sequentially stacked. Thereby, the multilayer wiring structure 10 is formed on the surface of the temporary substrate 13.

In this embodiment, the conductive post 17 is formed first and the interlayer insulating film 18 is formed around the conductive post 17. However, the interlayer insulating film 18 having an opening at the position where the conductive post 17 is formed is formed first, and the opening is formed. The conductive post 17 may be formed so as to fill the gap. Also in this case, it is desirable to form the interlayer insulating film and the conductive post by a droplet discharge method. In this embodiment, the wiring, the conductive posts, and the interlayer insulating film are finally fired in this order. However, they may be laminated and formed in a temporarily dried state, and finally the whole may be fired.
In this embodiment, the wiring, the conductive posts, and the interlayer insulating film are formed using the droplet discharge method. However, all or a part of these may be formed by a method other than the droplet discharge method.

  Next, as shown in FIG. 3A, second connection terminals 16 t are formed on the surface of the multilayer wiring structure 10. Specifically, as in FIG. 1A, a resist is applied to the surface of the fourth wiring layer, and the opening is patterned at the formation position of the second connection terminal by photolithography. Next, as in FIG. 1B, electrolytic plating or electroless plating is performed to form second connection terminals having a predetermined pattern in the openings of the resist. Finally, if the resist is removed, as shown in FIG. 3A, the second connection terminal 16t is formed on the surface of the fourth wiring layer 12d.

  Next, the temporary substrate 13 is removed. The temporary substrate 13 is removed by wet etching. The wet etching is performed by immersing the entire temporary substrate 13 on which the multilayer wiring structure 10 is formed in an etchant solution. In the present embodiment, it is necessary to etch only the temporary substrate 13 while leaving the second connection terminal 16t and the first connection terminal 16b. Therefore, etching is performed using an etchant having a higher etching rate for the temporary substrate 13 than the etching rate for the connection terminals 16b and 16t.

As a constituent material of the connection terminals 16b and 16t, Au having a low resistance value and stable is desirable. Therefore, Cu is selected as the constituent material (first material) of the temporary substrate 13, and a solvent containing ferric chloride (FeCl ₃ ) is selected as the etchant. Ferric chloride etches Cu but not Au. That is, in etching using ferric chloride as an etchant, the etching rate for Cu is higher than the etching rate for Au. Thereby, it is possible to etch only the temporary substrate 13 while leaving the connection terminals 16b and 16t.

Note that Cu may be selected as the constituent material of the temporary substrate 13 and a solvent containing CuCl ₂ may be selected as the etchant. Alternatively, Al may be selected as the constituent material of the temporary substrate 13 and a solvent containing sodium hydroxide (NaOH) may be selected as the etchant. Furthermore, stainless steel may be selected as the constituent material of the temporary substrate 13, and a solvent containing ferric chloride (FeCl ₃ ) may be selected as the etchant. In any case, a noble metal such as Au, Ag, Pt, or Pd can be selected as a constituent material of the connection terminals 16b and 16t.
In addition, it is also possible to remove only the temporary substrate 13 while leaving the first connection terminals 16b by polishing the temporary substrate 13 from the back surface.

  As a result, as shown in FIG. 3B, the multilayer double-sided wiring board 20 having the connection terminals 16b and 16t on both sides is formed.

As described in detail above, the method for manufacturing a wiring board according to the first embodiment forms a multilayer wiring structure having a first connection terminal on the temporary board side and a second connection terminal on the opposite side of the temporary board. And a step of removing the temporary substrate and exposing the first connection terminals formed on the back surface of the multilayer wiring structure. According to this configuration, since the first connection terminal is exposed by removing the temporary substrate, the via hole drilling process (laser via process) by the laser is not required. Therefore, a multilayer double-sided wiring board can be formed at low cost.
In addition, since the multilayer wiring structure is formed using a droplet discharge method, photolithography can be reduced and the manufacturing process can be simplified. In addition, since the material use efficiency is increased, a multilayer double-sided wiring board can be formed at low cost. Furthermore, the wiring and the conductive posts can be formed with high accuracy at predetermined positions.

Also, since the multilayer wiring structure and connection terminals are formed on the surface of the rigid temporary substrate, the patterning accuracy of the wiring and connection terminals is improved compared to the case where the multilayer wiring structure and connection terminals are formed on the surface of the resin layer, etc. It becomes possible to make it. Therefore, the pitch of the wiring and the connection terminal can be reduced.
The first connection terminal is formed by patterning a resist on the surface of the temporary substrate made of a conductive material and performing an electrolytic plating method. According to this configuration, since the resist is patterned on the surface of the hard temporary substrate, the patterning accuracy can be improved as compared with the case where the resist is patterned on the surface of the resin layer or the like. In addition, since the wiring is formed by a plating method, the pitch of the wiring can be reduced as compared with the conventional subtractive method (etching method). Furthermore, since the temporary substrate is made of a conductive material and the wiring is formed by the electrolytic plating method, the wiring can be easily formed in a shorter time than the electroless plating method.

[Second Embodiment]
Next, a method for manufacturing a wiring board according to the second embodiment will be described with reference to FIGS.
FIG. 4 is a process diagram of a method of manufacturing a wiring board according to the second embodiment. The method for manufacturing a wiring board according to the second embodiment is based on the point that the temporary substrate 30 in which the separation layer 34 made of the first material is formed on the surface of the reuse substrate (base) 32 made of the second material is used. This is different from the first embodiment using a temporary substrate made of only one material. Note that detailed description of portions having the same configuration as in the first embodiment is omitted.

First, as shown in FIG. 4A, a temporary substrate 30 in which a separation layer 34 is formed on the surface of a reuse substrate 32 is formed. The reuse substrate 32 is made of a glass material or the like, and a plurality of through holes 33 are formed from the back surface to the interface with the separation layer 34. The separation layer 34 is made of a metal material or the like and is formed to a thickness of about 0.5 μm by a sputtering method or the like.
Next, as shown in FIG. 4B, the multilayer wiring structure 10 is formed on the surface of the separation layer 34 in the temporary substrate 30, and the second connection terminals 16 t are formed on the surface of the multilayer wiring structure 10. The specific formation method is the same as in the first embodiment.

  Next, the temporary substrate 30 is removed. This step is performed by etching the separation layer 34 formed on the surface of the temporary substrate 30 to separate the reuse substrate 32 from the multilayer wiring structure 10. The separation layer 34 is etched by wet etching. In this wet etching, as in the first embodiment, only the separation layer 34 is etched while leaving the second connection terminal 16t and the first connection terminal 16b. In addition, in the second embodiment, only the separation layer 34 is etched without damaging the reuse substrate 32 made of a glass material or the like. Therefore, etching is performed using an etchant having an etching rate for the separation layer 34 higher than that for the connection terminals 16 b and 16 t and the reuse substrate 32. However, if glass, quartz, silicon, or the like is selected as the constituent material (second material) of the reuse substrate 32, the constituent materials of the connection terminals 16b and 16t, the constituent material of the separation layer 34 (first material), and the configuration of the etchant. As a material, it is possible to select the same material as in the first embodiment.

Wet etching can be easily performed by spraying an etchant with a spray or the like. This is because, in the first embodiment, dipping is employed to etch the entire temporary substrate, but in the second embodiment, it is sufficient to etch only the separation layer 34.
The separation layer 34 is etched from the side surface of the temporary substrate 30 by the sprayed etchant. In addition, in the second embodiment, since a plurality of through holes 33 are formed from the back surface of the reuse substrate 32 to the interface with the separation layer 34, the etchant enters through the through holes 33 and the separation layer 34 The interface is etched. Thereby, the separation layer 34 can be etched efficiently.
When the separation layer 34 is completely etched, the multilayer wiring structure 10 is separated from the reuse substrate 32 as shown in FIG. Thereby, the multilayer double-sided wiring board 20 provided with the connection terminals 16b and 16t on both sides is formed as in the first embodiment.

  As described in detail above, in the method for manufacturing a wiring board according to the second embodiment, a temporary substrate in which a separation layer made of the first material is formed on the surface of the reuse substrate made of the second material is used for separation. Only the layer was etched. According to this configuration, it becomes possible to reduce the consumption of the first material removed by etching, to shorten the removal time of the temporary substrate, and to reuse the reused substrate. Is possible. Therefore, a multilayer double-sided wiring board can be formed at low cost.

[Third Embodiment]
Next, a method for manufacturing a wiring board according to the third embodiment will be described with reference to FIG.
FIG. 5 is a process diagram of a method of manufacturing a wiring board according to the third embodiment. The method for manufacturing a wiring board according to the third embodiment is that a plurality of multilayer double-sided wiring boards 20a and 20b are formed at the same time by separating a plurality of multilayer wiring structures 10a and 10b on the surface of the temporary board 13. This is different from the first embodiment in which only one multilayer double-sided wiring board is formed. Note that detailed description of portions having the same configuration as in the first embodiment is omitted.

First, as shown in FIG. 5A, a temporary substrate 13 having a size capable of simultaneously molding a plurality of wiring substrates is prepared.
Next, the multilayer wiring structures 10a and 10b are spaced from each other on the surface of the temporary substrate 13, and the second connection terminals 16t are formed on the surfaces of the multilayer wiring structures 10a and 10b. The specific formation method is the same as in the first embodiment.

Next, the temporary substrate 13 is removed. The specific removal method is the same as in the first embodiment.
As a result, as shown in FIG. 5B, a plurality of multilayer double-sided wiring boards 20a and 20b having connection terminals 16b and 16t on both sides are formed.

As described in detail above, according to the method for manufacturing a wiring board according to the third embodiment, a plurality of wiring boards can be formed simultaneously.
In place of the method of manufacturing the wiring board according to the third embodiment, a multilayer wiring structure is provided on the entire surface of the temporary board described above, and after removing the temporary board, dicing or the like is performed, so that a plurality of wiring boards are formed. It may be formed separately.

[Electro-optical device]
Next, an electro-optical device provided with the wiring board according to the embodiment will be described with reference to FIG. FIG. 6 is a side sectional view of a liquid crystal display device as an example of an electro-optical device.

  The electro-optical device 100 is a liquid crystal display device and includes an electro-optical panel (liquid crystal panel) 110. The electro-optical panel 110 is mounted with a flexible wiring board (FPC) 20 formed by using the wiring board manufacturing method according to the embodiment. Since this FPC 20 has flexibility, it can be used by being bent in an arbitrary direction, and the electro-optical device 100 can be made compact.

  The electro-optical panel 110 is configured by bonding a pair of substrates 111 and 112 made of glass, plastic, or the like with a sealing material 113, and a liquid crystal (electro-optical material) 114 is enclosed between the substrates 111 and 112. . On the inner surface of the substrate 111, a plurality of pixel electrodes 111a made of a light-transmitting conductive material such as ITO (indium tin oxide) are arrayed, and an alignment film 111b is formed thereon. A counter electrode 112a made of the same light-transmitting conductive material is formed on the inner surface of the substrate 112, and an alignment film 112b is formed thereon. Further, polarizing plates 115 and 116 are disposed on the outer surfaces of the substrates 111 and 112.

  In the FPC 20, interlayer insulating films 318 and wirings 316 are alternately stacked. The upper and lower wirings 316 are connected by conductive posts 317 that penetrate the interlayer insulating film 318. A mounting land 313 is formed on the surface of the FPC 20, and Au plating 314 is applied to the surface to constitute a second connection terminal 316t. Further, Au plating 314 is applied to the back surface of the FPC 20 to form a first connection terminal 316b. That is, the FPC 20 is constituted by a multilayer double-sided wiring board having connection terminals 316b and 316t on both sides. Then, chip parts 304 and 306 such as a liquid crystal driving IC including a drive signal generation circuit of the electro-optical device 100 are mounted on the surfaces of the connection terminals 316b and 316t by solder reflow or the like.

On the other hand, the wiring 316 on the back surface of the FPC 20 is conductively connected to the wiring 111 c of the electro-optical panel 110 through an anisotropic conductive film 117. The wiring 111c is obtained by drawing out the pixel electrode 111a and the counter electrode 112a to an overhanging portion of the substrate 111 (a portion overhanging the outer shape of the substrate 112).
The drive signals output from the chip components 304 and 306 are transmitted to the electro-optical panel 110 via the wiring 316 and the conductive posts 317 and the anisotropic conductive film 117 of the FPC 20. Further, the drive signal is transmitted to the pixel electrode 111a and the counter electrode 112a via the wiring 111c of the electro-optical panel 110. As a result, the electro-optical panel 110 can be driven.

  The FPC 20 described above is formed at a low cost without performing via hole drilling processing (laser via processing) using a laser by using the method for manufacturing a wiring board according to the above embodiment. Therefore, by providing this FPC 20, the low-cost electro-optical device 100 can be provided.

[Electronics]
FIG. 7 is a perspective view of a mobile phone as an example of an electronic apparatus. A cellular phone 1300 shown in the figure includes the above-described electro-optical device as a small-sized display unit 1301 and includes a plurality of operation buttons 1302, a mouthpiece 1303, and a mouthpiece 1304.
The above-described electro-optical device is not limited to the above mobile phone, but an electronic book, a personal computer, a digital still camera, a liquid crystal television, a viewfinder type or a monitor direct-view type video tape recorder, a car navigation device, a pager, an electronic notebook, a calculator, It can be suitably used as an image display means for a word processor, a workstation, a videophone, a POS terminal, a device equipped with a touch panel, and the like. In any case, a low-cost electronic device can be provided.

  The technical scope of the present invention is not limited to the above-described embodiments, and includes those in which various modifications are made to the above-described embodiments without departing from the spirit of the present invention. That is, the specific materials and configurations described in the embodiments are merely examples, and can be changed as appropriate.

It is process drawing of the manufacturing method of the wiring board which concerns on 1st Embodiment. It is process drawing of the manufacturing method of the wiring board which concerns on 1st Embodiment. It is process drawing of the manufacturing method of the wiring board which concerns on 1st Embodiment. It is process drawing of the manufacturing method of the wiring board which concerns on 2nd Embodiment. It is process drawing of the manufacturing method of the wiring board which concerns on 3rd Embodiment. It is side surface sectional drawing of the liquid crystal display device as an example of an electro-optical apparatus. It is a perspective view of a mobile phone as an example of an electronic device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Multilayer wiring structure 13 ... Temporary board | substrate 16t ... 2nd connection terminal 16b ... 1st connection terminal 20 ... Multilayer double-sided wiring board

Claims (13)

  A first connection terminal, a conductive member, an insulating layer, and a second connection layer are formed on the surface of the temporary substrate containing the first material by using a droplet discharge method, and the temporary substrate is removed. A method of manufacturing a wiring board.   The method for manufacturing a wiring board according to claim 1, further comprising a step of forming a wiring, a second conductive member, and a second insulating layer between the insulating layer and the second connection layer. . Forming a multilayer wiring structure having a second connection terminal on the opposite side of the temporary substrate on the surface of the temporary substrate including the first material;
Removing the temporary substrate and forming a first connection terminal on the temporary substrate side of the multilayer wiring structure;
A method of manufacturing a wiring board, comprising: Forming a multilayer wiring structure having a first connection terminal on the temporary substrate side and a second connection terminal on the opposite side of the temporary substrate on the surface of the temporary substrate including the first material;
Removing the temporary base to expose the first connection terminal;
A method of manufacturing a wiring board, comprising:   5. The wiring board manufacturing method according to claim 3, wherein the first connection terminal is formed by patterning a mask material on a surface of the temporary base made of a conductive material and performing an electrolytic plating method. Method.   6. The method for manufacturing a wiring board according to claim 3, wherein the first connection terminal and the second connection terminal are made of a material whose main component is gold.   7. The method for manufacturing a wiring board according to claim 3, wherein the multilayer wiring structure is formed by using a droplet discharge method.   8. The method of manufacturing a wiring board according to claim 3, wherein the temporary substrate is formed by forming a separation layer made of the first material on a surface of the substrate made of the second material. . In the step of forming the multilayer wiring structure, a plurality of the multilayer wiring structures are spaced from each other on the surface of the temporary substrate,
The method of manufacturing a wiring board according to claim 3, wherein the temporary substrate is removed to obtain a plurality of wiring boards.   4. The step of removing the temporary substrate is performed by etching the temporary substrate using an etchant having an etching rate with respect to the first material larger than an etching rate with respect to a constituent material of the connection terminal. The manufacturing method of the wiring board in any one of Claim 9 thru | or 9.   11. The method of manufacturing a wiring board according to claim 10, wherein the first material contains copper as a main component, the connection terminal contains gold as a main component, and the etchant contains ferric chloride as a main component.   A wiring substrate manufactured using the method for manufacturing a wiring substrate according to claim 3.   An electro-optical device comprising the wiring board according to claim 12.

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