JP5195001B2 - Circuit board manufacturing method, circuit board, active matrix circuit board, and image display device - Google Patents

Description

  The present invention relates to a method for manufacturing a circuit board having an interlayer insulating film, a circuit board, an active matrix circuit board, and an image display device.

  Conventionally, multilayer wiring has been widely used in printed circuit boards and ceramic substrates in which ceramic green sheets are laminated. In multilayer wiring, a technique for connecting a lower wiring and an upper wiring separated by an interlayer insulating film through a contact hole (also referred to as a via hole) is required. Due to the trend toward higher integration and higher speed of LSIs, printed wiring boards and ceramic substrates are required to be mounted at high density, and in recent years, connection technology for upper and lower wiring using fine contact holes is important.

  Examples of methods for forming such contact holes include a photolithography method, a mechanical drill method, and a carbon dioxide laser or YAG laser irradiation method.

  The photolithography method is used in the LSI manufacturing process and has an advantage that the apparatus can be used as it is. Specifically, when a mask aligner is used as an exposure apparatus, a diameter of about 1 to 10 μm is used, and when a stepper is used, a very fine hole having a size of submicron or less is easily formed. be able to. However, the hole diameter used in the current printed circuit boards and ceramic substrates is about 50 to 300 μm, and although it can be formed by a photolithography method, in this case, in addition to the exposure apparatus, a resist coating apparatus, A developing machine, an etching device, a resist stripping device, and the like are required, and these devices are very expensive and cause an increase in cost. In addition, the photolithography method has disadvantages that it causes a cost increase due to a large number of steps and takes a long manufacturing time. From such a point, a method of forming with a mechanical drill that can reduce the cost, and a method of forming by irradiation with a carbon dioxide laser or a YAG laser are used.

The hole diameter formed by mechanical drilling or carbon dioxide laser or YAG laser irradiation is several tens to several hundreds [μm]. In order to satisfy the above, further miniaturization is required. Further, since the number of contact holes on the substrate is remarkably increased due to an increase in mounting density, it is also important to improve the throughput. For this reason, the screen printing method has attracted attention as a method capable of forming fine holes at once.

In the screen printing method, a part of the mesh is blocked by the emulsion, an opening (paste discharge area) of a desired shape is formed on the screen plate, the paste is placed on this screen plate, and printed with a squeegee, the paste discharge area In this technique, the paste is discharged and printed on a substrate or the like. In particular, in the off-contact method suitable for miniaturization, a gap (clearance) is provided between the screen plate and the substrate, and printing is performed while pressing with a squeegee. For this reason, immediately under the squeegee, a large shear stress is applied to the paste, and the paste becomes low in viscosity so that it can pass through the paste discharge region, and printing is performed on the substrate and the like. Further, since the printed paste is free from shear stress due to separation of the plate, the viscosity of the paste is restored, so that the shape can be maintained and a fine pattern can be formed. The screen printing method can form patterns provided on the screen plate in a lump, and is therefore a formation method with significantly higher throughput than a method of mechanically forming by a drill.

  However, when forming fine holes, the screen printing method has the following problems. That is, the viscosity of the paste is reduced by separating the plate and is printed on the substrate through the opening of the screen plate, and then the printed shape is maintained by recovering the viscosity, but the viscosity recovery time is limited. For this reason, generally, the pattern formed is larger than the paste discharge area. This is called sagging. When a contact hole is formed by the screen printing method, a paste sagging occurs from all around the contact hole, the paste spreads inside the formed contact hole, and the contact hole is blocked by the sagging. . For this reason, it has been practically limited to form contact holes with a diameter of about 200 to 300 μm in contact holes formed by screen printing.

  In fine pitch printing, it is necessary to use a high-definition mesh. Industrially, screen printing meshes are 400 to 500, and knitted stainless steel wires with a wire diameter of about 14 to 20 μm are used. The In high-density mounting, the required diameter of the contact hole is 10 to 50 μm. Therefore, when forming by the screen printing method, the size of the blocking region formed by the emulsion for forming the contact hole is 10 It becomes an isolated pattern of ˜50 μm. For this reason, the emulsion serving as the blocking region is held at about one place in the mesh, and even if fine contact holes can be formed by screen printing, the emulsion falls off the mesh during printing. It is not easy to say that it is a stable process with high yield. For this reason, the screen printing method is mainly used only in the formation of fine wiring and the contact hole filling process, and is not currently used when forming fine contact holes.

  Patent Documents 1, 2, and 3 disclose techniques for forming such contact holes by a screen printing method.

  In Patent Document 1, an interlayer insulating film is formed in a discontinuous band shape, a protrusion is formed on one edge side of the interlayer insulating film formed in a band shape, and the two protrusions are arranged to face each other. Thus, an apparently rectangular contact hole is formed. Note that a gap is provided at the tip of the protrusion that forms the contact hole. The screen printing method is more suitable for printing a fine line pattern than printing a fine hole pattern. At present, wiring with a line pattern of 10 to 30 μm is obtained, so this technique is used. As a result, fine holes can be formed.

  Further, Patent Document 2 discloses a method in which two meshes are overlapped and the size of the shielding area of the mesh arranged on the substrate is made smaller than that of the mesh arranged on the opposite side. Thereby, a contact hole having a stepped side surface is formed by printing. Since the contact holes to be formed are stepped, the sagging of the paste is reduced, making it difficult for the contact holes to be filled with the paste, and fine contact holes can be formed.

Moreover, in patent document 3, the printing process for forming a contact hole is divided into two times. In the first process, a part of the side wall of the contact hole is printed, and in the second process, the contact hole is formed. A method of forming the balance is disclosed. In particular, the first step is printed with a line pattern, and the second step is printed with a stepping stone-like dot pattern, whereby a contact hole of about 20 to 45 μm can be formed by printing. The present invention utilizes the fact that, in the screen printing method, the line pattern and the dot pattern are formed more finely than the hole pattern is formed. According to the present invention, the normal screen printing method is used. Then, it became possible to print a fine hole pattern that could not be formed. Further, the emulsion pattern in the screen plate described in Patent Document 3 has a line-shaped opening in the case of printing a line pattern, and has a dot-shaped opening in the case of printing a dot pattern. The emulsion pattern on the screen plate does not become an isolated pattern, and when screen printing is performed, the emulsion does not fall off from the screen plate, the yield is high, and the process is stable.
Japanese Patent Laid-Open No. 09-231903 Japanese Patent Laid-Open No. 10-39788 JP 2007-95783 A

  However, in the method described in Patent Document 1, since there is a gap at the tip of the protruding portion, when the upper wiring is formed on the interlayer insulating film, the upper electrode and the lower electrode can be short-circuited through the gap. There is sex. In order to prevent this, the design of the upper electrode is greatly limited. In addition, the space between the opposing lines is used as a contact hole, and sagging of paste from the line is inevitable, and it is difficult to form a minute contact hole.

  Further, in the method described in Patent Document 2, since the meshes are stacked, the thickness is increased, the amount of paste discharged increases, and it is difficult to suppress sagging itself. In other words, this method can be applied to the case where the thickness is the same, and can improve the yield of those having a diameter of 200 to 300 μm, which is the limit of contact holes in screen printing. However, it is not possible to form a fine contact hole.

  In addition, the method described in Patent Document 3 requires printing twice to form a contact hole, and avoids problems such as an increase in cost and a decrease in throughput when compared with a general screen printing method. could not.

  In particular, in flat panel displays such as liquid crystal display elements, EL elements, and electrophoretic display elements, active matrix drive circuits are used due to demands for high definition and high speed response. Is also an important issue.

  In view of the above problems, the present invention provides a circuit board manufacturing method, a circuit board, and an active matrix circuit board that can be formed at a low cost and a high throughput by simultaneously forming an interlayer insulating film and a contact hole at a low cost in a short time. An image display device is provided.

  The present invention is a circuit board comprising a multilayer wiring, wherein a contact hole for connecting a lower electrode and an upper electrode through an interlayer insulating film is two-dimensionally arranged in a matrix, A screen plate having paste discharge areas of a predetermined shape arranged two-dimensionally, and insulating paste discharged from three or more paste discharge areas adjacent to each other in the screen plate are joined two-dimensionally by sagging By doing so, it includes a printing step of performing printing so that the contact hole is formed, and a curing step of curing the printed insulating paste.

  In the printing process, the three or more adjacent paste discharge regions may be paste discharge regions that are closest to each other.

  Further, according to the present invention, the paste discharge areas in the screen plate used in the printing process are two-dimensionally arranged at equal intervals, and the insulating paste discharged from the four nearest paste discharge areas is used. The contact hole is formed.

  The present invention also relates to a method for forming a circuit board comprising a multilayer wiring, wherein contact holes for connecting a lower electrode and an upper electrode via an interlayer insulating film are two-dimensionally arranged in a matrix. In the Brookfield viscometer, an insulating paste having a viscosity measured using a No. 14 rotor of 50 [rpm] and 30 to 100 [Pa · s] is used, and a discharge area of a rectangular or circular paste is determined. Printing that prints the insulating paste on the circuit board by a screen plate that is two-dimensionally arranged in a matrix and that has a spacing of 20 to 50 [μm] between the adjacent ejection regions adjacent to each other And a curing step of curing the printed insulating paste.

  The present invention also provides an insulating material filling step of filling the contact hole with an insulating paste for a part of the contact holes formed by the hardening step, and forming the filling insulating layer by hardening the filled insulating paste. And a second curing step.

  In addition, the present invention includes a connection electrode forming step of filling a contact hole formed of a hardened insulating paste with a conductive material after completion of the curing step in the method for forming an interlayer insulating film.

  In addition, the present invention includes a connection electrode forming step of filling a contact hole formed of a cured insulating paste with a conductive material after completion of the second curing step in the method for forming an interlayer insulating film. .

Further, the present invention is a circuit board comprising a multilayer wiring, wherein the contact holes for connecting the lower electrode and the upper electrode through the interlayer insulating film are two-dimensionally arranged in a matrix form, interlayer insulating film be one that is formed by screen printing using a screen plate having a paste ejection exit area of a predetermined shape are arranged two-dimensionally, the insulating paste discharged from the paste ejection region Of these, the contact holes are formed by two-dimensionally joining the insulating pastes discharged simultaneously from three or more adjacent paste discharge regions.

Further, the present invention includes three or more paste discharge region before Symbol proximity, characterized in that it is a paste discharge region that is closest to each other.

  Further, according to the present invention, in the screen plate, the paste discharge areas are two-dimensionally arranged at equal intervals, and the contact holes are formed by insulating paste discharged from the four nearest paste discharge areas. It is characterized by.

  Further, according to the present invention, an interval between the adjacent discharge regions adjacent to each other in the screen plate is 20 to 50 [μm], and the insulating paste is a No. 14 rotor in a Brookfield viscometer. Viscosity measured by using 50 is [rpm] and is 30 to 100 [Pa · s].

  Further, the present invention is characterized in that a filling insulating layer is formed by filling an insulating material for a predetermined contact hole among the contact holes.

  The present invention is characterized in that the upper electrode and the connection electrode formed by embedding the contact hole are formed at the same time.

  Further, the present invention is characterized in that the connection electrode formed by embedding the upper electrode and the contact hole is formed by a printing method.

  In addition, the present invention is characterized in that the electrical wiring on the circuit board is electrically connected to the two-dimensionally arranged transistors or diodes.

  Further, the present invention is characterized in that an image display element is laminated on an active matrix circuit board.

  According to the present invention, even a contact hole with a fine pattern can be formed at the same time as the interlayer insulating film. Therefore, a method for manufacturing a circuit board that can be formed at low cost and high throughput, a circuit board, and an active matrix circuit A substrate and an image display device can be provided.

  The present invention utilizes the phenomenon of sagging caused by the above-described screen printing method, and forms a dot pattern contact hole from a screen plate having a paste ejection region of a todd pattern that is a reverse pattern to the conventional pattern. It is.

  Hereinafter, the best mode for carrying out the present invention will be described.

[First Embodiment]
A first embodiment according to the present invention will be described.

  FIG. 1 shows a screen plate 11 for forming an interlayer insulating film having contact holes by screen printing in this embodiment.

  This screen plate is made of a 500 mesh stainless steel wire, and a part of the surface of the screen plate is configured such that an emulsion is formed according to the pattern to be formed and the paste is not transmitted. In the present embodiment, 641 × 481 rectangular paste discharge regions 12 (openings not blocked by the emulsion) are two-dimensionally arranged at a pitch of 127 μm. In FIG. 1, only a part of the number of paste discharge regions 12 is shown for convenience. The paste discharge area 12 is 87 × 87 μm.

  As a result, the distance A and the distance B between the areas 12a and 12b and the areas 12a and 12d, which are the adjacent paste discharge areas adjacent to each other, are 40 μm, respectively, and the next adjacent paste discharge area 12 The distance C between the region 12a and the region 12c is 56.6 μm.

  The insulating paste used in the present embodiment is connected to each other due to the influence of sagging when the insulating paste discharged from the closest paste discharge area is screen-printed using the screen plate. The insulating pastes discharged from the adjacent paste discharge regions are in a condition that they do not come into contact with each other even if they are affected by sagging. That is, in the screen printing method, when paste is ejected at intervals of 40 μm, they are interconnected and integrated due to the influence of sagging, and when the paste is ejected at intervals of 56.6 μm, they are affected by sagging. Is a condition that keeps the separated state without contact. In other words, using the sagging generated when the insulating paste is printed in the screen printing method, the dot pattern insulating paste formed when the screen printing is performed by the screen plate on which the dot pattern paste discharge area is formed. When the closest patterns are brought into contact with each other and integrated, a contact hole is formed in a region surrounded by the closest insulating pastes.

  As such an insulating paste, the viscosity measured using a No. 14 rotor in a Brookfield viscometer in an environment of 25 ° C. as described later is 50 [rpm] and 30 to 100 [Pa · s]. One insulating paste is mentioned.

  The shape of the contact hole to be formed is based on the use of the screen plate such as the shape of the paste discharge area in the screen plate, the viscosity of the insulating paste, the number of meshes, the thickness, and the emulsion thickness. Depends on printing conditions such as rubber hardness and attack angle. In the case of a rectangular paste discharge region, the shape is often rhombus. The discharged insulating paste is then cured by drying or the like to form an interlayer insulating film.

  Next, a method for forming a screen plate used in this embodiment will be described.

  First, a stainless steel mesh No. 500 is attached to the screen plate frame with a predetermined tension in a double bias combination through a nylon mesh.

  Next, emulsion coating and baking are repeated on one surface of the stainless mesh to form an emulsion having a predetermined thickness.

  Next, a 87 × 87 μm paste discharge area is adhered to the formed emulsion surface at a 127 μm pitch and a Cr mask having a pattern having the same shape as the paste discharge area arranged in a two-dimensional matrix. Then, exposure is performed by an exposure apparatus.

  Next, by developing the screen plate after exposure, the emulsion in the area exposed by the exposure apparatus is peeled off. Thereafter, the emulsion in the area that has not been exposed is thermally cured, so that the paste discharge area becomes 2 A screen plate is formed that is dimensionally arranged in a matrix. Thereby, it is possible to obtain a screen plate in which the distance between the closest paste discharge regions is 40 μm.

  Next, a method for forming an interlayer insulating film by a screen printing method using the screen plate thus produced will be described with reference to FIG.

  First, as shown in FIG. 2A, the insulating paste 23 was printed on the substrate 21 made of PET (polyethylene terephthalate) using the screen plate 22 produced as described above. An insulating paste is an ink in which an insulating filler having a size of 0.01 to several μm is dispersed in an organic vehicle composed of a polymer resin and an organic solvent. When shearing stress is applied, the viscosity decreases and the shearing stress disappears. It has the property of restoring viscosity. The insulating paste 23 used in the present embodiment is a silica paste, and is made of silica filler having a size of 0.2 to 0.6 μm, a polyester resin, butyl carbitol acetate, and the like. The viscosity measured using a 14 rotor is 50 [rpm] and 62 [Pa · s]. The clearance between the screen plate 22 and the substrate 21 made of PET was 1.5 [mm], and printing was performed using a squeegee with a rubber hardness of 70 at an attack angle of 70 degrees and a printing speed of 60 mm / s. . As shown in FIG. 2 (a), the clearance is zero immediately below the squeegee 24, but as shown in FIG. 2 (b), as the squeegee 24 moves, the separation of the plate advances behind the squeegee 24. The insulating paste is transferred from the paste discharge area of the screen plate 22 to the PET 21 substrate, and a pattern 25 made of the insulating paste is formed. Thereafter, the insulating paste patterns that are closest to each other due to sagging come into contact with each other to be integrated.

  This will be described in more detail with reference to FIGS. FIG. 3 is a top view of the surface of the interlayer insulating film formed according to the present embodiment. Insulating paste is ejected from the paste ejection areas 12a, 12b, 12c, and 12d of the screen plate shown in FIG. 1, and the insulating paste patterns 25a, 25b, 25c, and 25d are formed on the substrate 21 as shown by the wavy lines in FIG. In this pattern, the insulating paste patterns 25 that are closest to each other are brought into contact with each other and integrated.

  That is, in this embodiment, the patterns 25 of the closest insulating paste (25a and 25b, 25b and 25d, 25d and 25c, and 25c and 25a) proceed toward the wavy arrows due to sagging and contact each other. However, since the adjacent insulating paste patterns 25 (25a and 25c, 25b and 25d) are not in contact with each other, the four insulating paste patterns 25a, 25b, 25c, and 25d 25 are used. Thus, one contact hole 26a is formed. Therefore, after printing on the substrate 21 by the screen plate 22 having 641 × 481 paste discharge regions 12, an interlayer insulating film having 640 × 480 contact holes 26 is formed. Note that the contact hole 26 formed in the present embodiment is formed in a square, diamond, or star shape.

  Next, as shown in FIG. 2 (c), the substrate 21 made of PET, which had been printed with the insulating paste by screen printing, was placed in a forced convection oven 27 and heated to cure the insulating paste. The curing conditions in the forced convection oven 27 at this time are a temperature of 120 ° C. and 30 minutes.

  A photograph taken by a metallographic microscope in a part of the interlayer insulating film formed by such a process is shown in FIG. As shown in FIG. 4, contact holes (holes) were formed in the interlayer insulating film, and as a result of the measurement, it was confirmed that all 640 × 480 holes were opened.

  Next, the surface shape of the interlayer insulating film thus formed will be described with reference to FIGS. As shown in FIG. 3, contact holes 26 are two-dimensionally arranged in a matrix on a substrate 21 made of PET.

  FIG. 5 shows a cross-sectional configuration of the substrate 21 on which the interlayer insulating film 28 is thus formed. 3A is a sectional view taken along the wavy line A1-A2 in FIG. 3, FIG. 5B is a sectional view taken along the wavy line B1-B2, and FIG. 5B is a sectional view taken along the wavy line C1-C2. c). In FIG. 5A, contact holes 26a, 26b, and 26c are formed. Between the contact holes 26, the discharged insulating paste patterns 25a and 25c are ejected regions and have a raised shape. Yes. That is, although the sagging occurs between the discharged insulating paste patterns 25a and 25c, the insulating paste does not come into contact with each other, so that the contact hole 26a is formed.

  On the other hand, as shown in FIG. 5 (b), contact holes are formed between the discharged insulating paste patterns 25a and 25b because the insulating paste patterns 25a and 25b are joined to each other by sagging. It will never be done. Therefore, although the interlayer insulating film in the region where the insulating paste patterns 25a and 25b are formed is in a raised state, the insulating paste is joined by sagging in the region between the insulating paste patterns 25a and 25b. The interlayer insulating film is formed thin.

  Similarly, as shown in FIG. 5C, since the insulating paste patterns 25a and 25d are joined to each other between the discharged insulating paste patterns 25a and 25d, contact holes are formed. Never formed. Therefore, although the interlayer insulating film in the region where the insulating paste patterns 25a and 25d are formed is in a raised state, the insulating paste is joined by sagging in the region between the insulating paste patterns 25a and 25d. The interlayer insulating film is formed thin. Thus, the dot pattern contact hole 26 shown in FIG. 3 can be obtained from the screen plate 11 having the dot pattern paste discharge area 12 shown in FIG.

  If the size of the contact hole is about 200 to 300 [μm], the contact is not affected by the present embodiment, but by the normal pattern, that is, the pattern surrounded by the paste discharge area by the emulsion of the screen plate. Holes can be formed.

  In the present embodiment, the substrate 21 made of PET is used. In addition, a glass substrate, a quartz substrate, a ceramic substrate, PES (polyethersulfone), PEN (polyethylene naphthalate), PI (polyimide), PC ( It is also possible to use a plastic substrate such as polycarbonate) or a semiconductor substrate such as Si or GaAs.

  In this embodiment, silica paste made of silica filler, polyester resin, butyl carbitol acetate, etc. is used as the insulating paste, but any other material that can handle fine pitch printing can be used. It is. As the filler, it is possible to use an insulating filler such as silica, alumina, titanium oxide, and barium titanate, and a dielectric filler. As the polymer resin, resins such as polyester resin, polyethylene resin, acrylic resin, ethyl cellulose resin, polystyrene resin, polyimide resin, polyamide resin, polyvinyl alcohol resin, and polyvinyl acetal resin can be used. Further, as the organic solvent, a high boiling point solvent such as butyl carbitol acetate, butyl carbitol, ethylene carbitol, ethylene carbitol acetate, alpha terpineol, isophorone, or diclime can be used. Moreover, additives, such as a dispersing agent, an antifoamer, and a thickener, may be added as needed.

  In the present embodiment, the thermosetting paste has been described. However, in the present embodiment, various methods can be adopted as the curing method. Specifically, it may be of a photocuring type, a combination of photocuring and thermosetting, or a type in which the resin itself is burned out by baking after drying.

  In the screen plate in this embodiment, the paste discharge area is formed by emulsion on the stainless steel mesh, but the suspended mesh is formed by forming the paste discharge area with a metal stay such as Ni, Cu, etc., and fixed to the stainless steel mesh. May be used. Further, a mesh knitted with polymer fibers can be used as long as the number of meshes can be used for fine pitch printing, generally 400 mesh or more.

[Second Embodiment]
In the second embodiment, the relationship between the space between the paste discharge regions and the contact hole to be formed is examined. In the screen plate, 321 × 241 square paste discharge areas have a period of 127 [μm], and the interval between adjacent paste discharge areas is 10 [μm], 20 [μm], 30 in a two-dimensional matrix. [Μm], 40 [μm], 50 [μm], 60 [μm], and 80 [μm] were produced. The screen plate has a mesh of 500 mesh and an emulsion thickness of 15 [μm].

  On the screen plate, using the same insulating paste as that used in the first embodiment, using a squeegee with a rubber hardness of 80, a clearance of 1.5 [mm], an attack angle of 70 [degrees], printing The insulating paste was printed on a PET substrate under the condition of a speed of 30 [mm / s], and then cured at 120 [° C.] for 30 [min]. Table 1 shows the result of observing the shape of the contact hole with a metal microscope after the insulating film was cured.

As shown in Table 1, when the paste discharge area is square and the space between adjacent paste discharge areas is 10 [μm], not only the pattern of the insulating paste closest to each other, Next, the insulating paste pattern next to each other was also brought into contact with each other due to sagging, and almost no contact holes were formed. On the other hand, when the space between adjacent paste discharge areas is set to 60 [μm], some of the closest insulating paste patterns do not come into contact with each other due to sagging, and there are areas where contact holes are not partially formed. there were. Further, in the case where the space between adjacent paste discharge areas is 80 [μm], all the insulating paste patterns are not contacted by sagging, and all contact holes are not touched. In other words, an insulating material isolated pattern is formed, and the contact holes are connected to each other. In addition, when the space between adjacent paste discharge areas is 20 [μm], 30 [μm], 40 [μm], and 50 [μm], all the adjacent insulating paste patterns are in contact with each other by sagging. The next adjacent insulating paste patterns were not contacted by sagging, and all 320 × 240 contact holes had openings. From this result, it is desirable that the space between adjacent paste discharge areas of the screen plate is 20 to 50 [μm].

[Third Embodiment]
In the third embodiment, the relationship between the viscosity of the insulating paste and the formed contact hole is examined. A screen plate having a size of 321 × 241 circular paste discharge areas with a period of 127 [μm] and an interval between adjacent paste discharge areas of 40 [μm] in a two-dimensional matrix was prepared. The screen plate has a mesh of 530 mesh and an emulsion thickness of 10 [μm].

  On the above screen plate, the viscosity measured using a No. 14 rotor in a Brookfield viscometer is 50 [rpm], 10 [Pa · s], 30 [Pa · s], 62 [Pa · s], 100 About each insulating paste which is [Pa * s] and 150 [Pa * s], it printed on the board | substrate which consists of PET through the said screen plate, and hardened | cured at 120 degreeC for 30 minutes. Other printing conditions were the same as in the second embodiment, and the shape of the contact hole after curing was observed with a metal microscope. The results are shown in Table 2.

When the viscosity of the insulating paste is 10 [Pa · s], the pattern of the insulating paste formed by printing is not only the pattern of the insulating paste closest to each other, but also the pattern of the insulating paste next closest to each other. As a result, they were in contact with each other, and almost no contact holes were formed. On the other hand, in the case where the viscosity of the insulating paste is 150 [Pa · s], there is a region in which the contact hole is not partially formed because there is a part of the closest insulating paste pattern that does not come into contact even by sagging. . In addition, when the viscosity of the insulating paste is 30 [Pa · s], 62 [Pa · s], and 100 [Pa · s], all of the closest insulating paste patterns are brought into contact with each other and integrated. Then, the adjacent insulating paste patterns were not brought into contact with each other by sagging, and all 320 × 240 contact holes had openings. From this result, it is desirable that the viscosity of the insulating paste used is 30 to 100 [Pa · s] when the viscosity measured using a No. 14 rotor in a Brookfield viscometer is 50 [rpm].

[Fourth Embodiment]
Next, a fourth embodiment will be described. The fourth embodiment is a multilayer wiring board and a method for forming a multilayer wiring board according to the present invention.

  Based on FIG. 6, the structure of the multilayer wiring board in this Embodiment is demonstrated. 6A is a top view of the multilayer wiring board according to the present embodiment, and FIG. 6B is a multilayer wiring board according to the present embodiment cut along a broken line D1-D2 in FIG. 6A. FIG.

  The lower electrodes 32 of the multilayer wiring board in the present embodiment are formed on the substrate 31, extend in the left-right direction on the paper surface in FIG. 6A, and have 640 pieces at a pitch of 127 [μm] in the up-down direction. The lower electrode 32 is formed. An insulating film 34 is formed on the lower electrode 32, and 640 × 480 contact holes are formed in the insulating film 34 so that the surface of the lower electrode 32 is exposed. The shape of the contact hole is a rhombus having a width of about 20 to 40 [μm], and the contact hole is filled with metal to form a via hole 35. The 640 × 480 upper electrodes 36 formed on the insulating film 34 are connected to the lower electrode 32 through contact holes, respectively.

  Based on FIG. 7, the manufacturing method of the multilayer wiring board in this Embodiment is demonstrated.

  First, as shown in FIG. 7 (a), an Ag paste is printed on a substrate 31 made of PET by a screen printing method and cured at 140 [° C.] and 30 [min], thereby forming a lower portion. An electrode 32 was formed. The lower electrodes 32 extend in the left-right direction in the drawing, and are formed in a length of 640 with a pitch of 127 [μm] in the direction perpendicular to the paper surface. The line width of the lower electrode 32 is 60 [μm]. The Ag paste used for printing is an ink in which an Ag filler having a size of 0.1 to 1.0 [μm] is dispersed in an organic vehicle composed of an acrylic resin and butyl carbitol. The viscosity is measured using a Brookfield viscometer. When measured using a No. 14 rotor, 10 [rpm] and 240 [Pa · s].

  The screen plate used for printing the lower electrode 32 is made of stainless steel 500 mesh, and a nylon mesh and a double bias combination are pasted, and the thickness of the emulsion is 10 [μm]. When performing printing, a squeegee with a clearance of 1.5 mm and a rubber hardness of 70 is used, the attack angle is 70 degrees, and the printing speed is 80 mm / s. An alignment mark for alignment is also formed around the lower electrode 32 at the same time.

  Next, as shown in FIG. 7B, 640 × 480 contact holes 33 arranged in a two-dimensional matrix are formed on the lower electrode 32 by the same method as in the first embodiment. In this way, the insulating film 34 is formed by printing the insulating paste by screen printing and curing it at 120 [° C.] and 30 [min]. In addition, in order to form 640 × 480 contact holes 33 on the lower electrode 32, alignment is performed by using an alignment mark formed simultaneously with the formation of the lower electrode 32 and an alignment mark formed in advance on the screen plate. After that, the insulating paste is printed. At this time, alignment marks formed on the screen plate are also transferred onto the substrate 31.

  Next, as shown in FIG. 7C, a via hole 35 was formed by depositing Ni in the formed contact hole 33 by electrolytic plating.

  Next, as shown in FIG. 7 (d), the upper electrode 36 was formed by printing an Ag paste on the via hole 35 by screen printing and curing at 140 [° C.] and 30 [min]. . The formed upper electrode 36 has a rectangular shape of 100 × 100 [μm], and is formed on the surface of the substrate 31 in a two-dimensional manner with a pitch of 127 [μm] and 640 × 480. As described above, in order to surely form all the upper electrodes 36 on the via holes 35, the alignment marks formed simultaneously with the formation of the insulating film 34 and the screen plate for forming the upper electrodes 36 are formed. After alignment with the alignment mark, the upper electrode 36 was formed by screen printing.

  The Ag paste, screen plate, printing conditions, etc. used for printing the upper electrode 36 are the same as the conditions for forming the lower electrode 32. When a voltage of 0.01 [V] was applied between the upper electrode 36 and the lower electrode 32 to check conduction, all the upper electrodes 36 were electrically connected to the lower electrode 32.

  In the present embodiment, after the lower electrode 32 is formed, 640 × 480 fine contact holes 33 arranged in a two-dimensional matrix are formed in the lower electrode 32 by the same method as in the first embodiment. In addition, the contact hole is filled with a conductive material, and then the upper electrode 36 is formed on the via hole 35. Therefore, the fine via hole 35 allows the upper wiring composed of the upper electrode 36 and the lower wiring composed of the lower electrode 32 to be formed. The connected multilayer wiring can be easily manufactured.

  In this embodiment, the contact hole 33 is filled by electrolytic plating of Ni. However, the conductive material is not limited to Ni, and Al, Ag, Au, Cr, Cu, Pt, etc. Metals, alloys, and carbon can be used. In addition, as a method for filling the contact hole 33, a method such as an electroless plating method, a screen printing method, a gravure offset printing method, a dispenser method, an ink jet method, or photolithography can be used.

In the present embodiment, the lower electrode 32 and the upper electrode 36 are formed by screen printing using Ag paste. However, the material and the forming method are not limited to this, and the material is Al. It is possible to use a metal or alloy such as Ag, Au, Cr, Cu, or Pt, or an oxide transparent conductive material such as carbon, ITO, or SnO ₂ . As for the formation method, methods such as an electrolytic plating method, an electroless plating method, a screen printing method, a gravure offset printing method, a dispenser method, an ink jet method, and a photolithography method can be used. In addition, screen printing methods, gravure offset printing methods, dispenser methods, ink jet methods, and other printing methods are simpler than the electroplating method, electroless plating method, and photolithography method, so the cost is lower. Multi-layer wiring can be formed.

  In this embodiment, the case of two-layer wiring has been described. However, by repeating the method in this embodiment, multilayer wiring of three or more layers can be formed.

[Fifth Embodiment]
Next, a fifth embodiment will be described. The fifth embodiment is a multilayer wiring board and a method for forming a multilayer wiring board according to the present invention.

  Based on FIG. 8, the structure of the multilayer wiring board in this Embodiment is demonstrated. FIG. 8A is a top view of the multilayer wiring board in the present embodiment, and FIG. 8B is a multilayer wiring board in the present embodiment cut along the broken line E1-E2 in FIG. 8A. FIG.

  The lower electrodes 42 of the multilayer wiring board in the present embodiment are formed on the board 41, extend in the left-right direction on the paper surface in FIG. 8A, and 640 pieces at a pitch of 127 [μm] in the up-down direction. The lower electrode 42 is formed. An insulating film 44 is formed on the lower electrode 42, and 640 × 480 contact holes are formed in the insulating film 44 so that the surface of the lower electrode 42 is exposed. The shape of the contact hole is a rhombus having a width of about 20 to 40 [μm], and the contact hole is filled with metal at the same time when the upper electrode 45 is formed. Each of the 640 × 480 upper electrodes 45 formed in the circuit is connected to the lower electrode 32 through a contact hole.

  Based on FIG. 9, the manufacturing method of the multilayer wiring board in this Embodiment is demonstrated.

  First, as shown in FIG. 9A, an Ag paste is printed on a substrate 41 made of PET by a screen printing method and cured at 140 [° C.] and 30 [minutes], thereby forming a lower portion. An electrode 42 was formed. In the drawing, the lower electrodes 42 extend in the left-right direction, and 640 pieces are formed at a pitch of 127 [μm] in a direction perpendicular to the paper surface. The line width of the lower electrode 42 is 60 [μm]. The Ag paste used for printing is an ink in which an Ag filler having a size of 0.1 to 1.0 [μm] is dispersed in an organic vehicle composed of an acrylic resin and butyl carbitol. The viscosity is measured using a Brookfield viscometer. When measured using a No. 14 rotor, 10 [rpm] and 240 [Pa · s].

  The screen plate used for printing of the lower electrode 42 is made of stainless steel 500 mesh, a nylon mesh and a double bias combination are pasted, and the thickness of the emulsion is 10 [μm]. When performing printing, a squeegee with a clearance of 1.5 mm and a rubber hardness of 70 is used, the attack angle is 70 degrees, and the printing speed is 80 mm / s. An alignment mark for alignment is also formed around the lower electrode 42 at the same time.

  Next, as shown in FIG. 9B, 640 × 480 contact holes 43 arranged in a two-dimensional matrix are formed on the lower electrode 42 by the same method as in the first embodiment. As described above, the insulating paste 44 is printed by screen printing and cured at 120 [° C.] and 30 [minutes] to form the insulating film 44. In order to form 640 × 480 contact holes on the lower electrode 42, alignment is performed by using the alignment mark formed at the same time when the lower electrode 42 is formed and the alignment mark previously formed on the screen plate. After that, the insulating paste is printed. At this time, alignment marks formed on the screen plate are also transferred onto the substrate 41.

  Next, as shown in FIG. 9C, the Ag paste is embedded in the contact hole 43 by printing the Ag paste by screen printing and curing at 140 [° C.] for 30 minutes. The upper electrode 45 was formed at the same time. The formed upper electrode 36 has a rectangular shape of 100 × 100 [μm], and is formed on the surface of the substrate 41 in a two-dimensional manner with a pitch of 127 [μm] and 640 × 480. As described above, in order to reliably connect all the upper electrodes 45 to the lower electrode 42 through the contact holes 43, the alignment marks and the upper electrode 45 formed simultaneously with the formation of the insulating film 44 are formed. After alignment with the alignment mark formed on the screen plate for the purpose, the contact hole 43 was embedded and the upper electrode 45 was formed by screen printing.

  The Ag paste, screen plate, printing conditions, and the like used for printing the upper electrode 45 are the same as the conditions for forming the lower electrode 42. When a voltage of 0.01 [V] was applied between the upper electrode 45 and the lower electrode 42 to check conduction, all the upper electrodes 45 were electrically connected to the lower electrode 42.

  In the present embodiment, after the lower electrode 42 is formed, 640 × 480 fine contact holes 43 arranged in a two-dimensional matrix are formed in the lower electrode 42 by the same method as in the first embodiment. In addition, the upper electrode 45 is formed by filling the contact hole 43 with a conductive material and forming the upper electrode 45 at the same time, so that the upper wiring and the lower electrode 42 composed of the upper electrode 45 are formed by the electrodes formed in the minute contact hole 43. It is possible to easily produce a multilayer wiring to which the lower wiring made of is connected.

  In this embodiment, the upper electrode 45 is formed by a screen printing method using an Ag paste. However, the upper electrode 45 may be formed of a material or a formation method capable of simultaneously filling the contact hole 43 and forming the upper electrode 45. Applicable if available. Specifically, as a material, metals and alloys such as Al, Ag, Au, Cr, Cu, and Pt, conductive paste such as carbon, and conductive ink can be used. In this case, the viscosity is suitable for printing. It can be used by adjusting. As for the forming method, a gravure offset printing method, a dispenser method, an ink jet method, or the like can be used. The screen printing method described in the present embodiment is suitable for forming a thick film as compared with other printing methods. Therefore, when the contact hole 43 is embedded and the upper electrode 45 is simultaneously formed, Is suitable.

  In this embodiment, the case of two-layer wiring has been described. However, by repeating the method in this embodiment, multilayer wiring of three or more layers can be formed.

[Sixth Embodiment]
Next, a sixth embodiment will be described. The sixth embodiment is an active matrix circuit board and a method for forming an active matrix circuit board according to the present invention.

  Based on FIG. 10, the structure of the active matrix circuit board in this Embodiment is demonstrated. FIG. 10 shows a simplified configuration in which the number of TFTs is reduced. FIG. 10A is a top view of the active matrix circuit board according to the present embodiment, and FIG. 10B is an active matrix according to the present embodiment cut along a broken line F1-F2 in FIG. It is sectional drawing of a circuit board.

The active matrix circuit board according to the present embodiment has 640 × 480 TFTs (thin film transistors) arranged in a two-dimensional matrix on a substrate 51 made of polyimide (PI) at a pitch of 127 [μm]. Yes. TFT includes a gate electrode 52 is formed of Al formed on the substrate 51, the drain electrode 54, the source electrode 55 and the electrode, the semiconductor layer 56 formed by the gate insulating film 53, a-Si of SiO ₂ It will be. An insulating film 57 is formed on the TFT, and the drain electrode 54 of the TFT has a size of 100 × 100 [μm] at a pitch of 127 [μm] through a contact hole formed in the insulating film 57. Are connected to the individual electrodes 59 formed in

  In addition, each gate electrode 52 is connected to 480 gate lead-out wirings 61, and each source electrode 55 is connected to 640 source lead-out wirings 62. 62 is connected to an IC driver (not shown).

  When a selection signal is input from the IC driver to the gate electrode 52 via the gate lead-out wiring 61 and a data signal is input to the source electrode 55 via the source lead-out wiring 62, the TFT operates. Specifically, the TFT having the gate electrode 52 to which the selection signal is input performs an ON operation or an OFF operation according to the data signal input to the source electrode 55.

  Next, a method for manufacturing the active matrix substrate in the present embodiment will be described.

  First, as shown in FIG. 11, a gate electrode 52 is formed on a substrate 51 made of PI. Specifically, after an Al film is formed on the substrate 51 by sputtering, a photoresist is applied to the surface of the formed Al film, prebaked, and then exposed and developed by an exposure apparatus. The same resist pattern as the gate electrode 52 to be formed is formed. Thereafter, the Al film in a region where the resist is not formed is removed by etching such as RIE (reactive ion etching) to form the gate electrode 52 made of Al. 11A is a top view of the substrate 51, and FIG. 11B is a cross-sectional view taken along a broken line G1-G2 in FIG. 11A.

Next, as shown in FIG. 12, a gate insulating film 53 made of SiO ₂ is formed so as to cover the gate electrode 52 formed on the substrate 51. Specifically, the gate insulating film 53 made of SiO ₂ is formed by plasma CVD while masking is performed so that the gate insulating film 53 is not formed only on the region of the gate lead-out wiring 61. 12A is a top view of the substrate 51, and FIG. 12B is a cross-sectional view taken along a broken line H1-H2 in FIG. 12A.

  Next, as shown in FIG. 13, the drain electrode 54 and the source electrode 55 are formed. Specifically, after an Al film is formed on the gate insulating film 53 in the substrate 51 by sputtering, a photoresist is applied to the surface of the formed Al film, prebaked, and then exposed by an exposure apparatus. By performing development, the same resist pattern as the drain electrode 54 and the source electrode 55 to be formed is formed. Thereafter, the Al film in the region where the resist is not formed is removed by etching by RIE or the like, thereby forming the drain electrode 54 and the source electrode 55 made of Al. 13A is a top view of the substrate 51, and FIG. 13B is a cross-sectional view taken along a broken line J1-J2 in FIG. 13A.

  Next, as shown in FIG. 14, a semiconductor layer 56 made of a-Si (amorphous silicon) is formed. Specifically, after forming an a-Si film on the surface of the substrate 51 on which the gate insulating film 53 is formed by plasma CVD, a photoresist is applied on the formed a-Si film, After pre-baking, a resist pattern identical to the pattern of the semiconductor layer 56 to be formed is formed by exposure and development with an exposure apparatus. Thereafter, the a-Si film in a region where the resist is not formed is removed by etching such as RIE (reactive ion etching), so that the semiconductor layer 56 made of a-Si is in contact with the drain electrode 54 and the source electrode 55. Form. As a result, 640 × 480 semiconductor layers 56 made of a-Si are formed in a two-dimensional matrix at a pitch of 127 [μm]. 14A is a top view of the substrate 51, and FIG. 14B is a cross-sectional view taken along a broken line K1-K2 in FIG. 14A.

  Next, as shown in FIG. 15, an insulating film 57 is formed on the formed TFT. Specifically, using the screen plate described in the first embodiment, it is composed of a silica filler having a size of 0.2 to 0.6 μm, a polyester resin, butyl carbitol acetate, etc., and a Brookfield viscometer. In No. 14, an insulating paste having a viscosity of 50 [rpm] and 62 [Pa · s] measured using a No. 14 rotor was used. Specifically, the clearance from the screen plate was 1.5 [mm], and printing was performed using a squeegee with a rubber hardness of 70 at an attack angle of 70 [degrees] and a printing speed of 60 [mm / s]. The contact holes 58 formed by forming the insulating film 57 were printed after alignment so that each contact hole 58 was formed on the drain electrode 54. As a result, 640 × 480 contact holes 58 are formed on the drain electrodes 54 of the 640 × 480 TFTs.

  The insulating film 57 was formed by heating the substrate 51 after the printing of the insulating paste in a forced convection oven and curing the insulating paste. 15A is a top view of the substrate 51, and FIG. 15B is a cross-sectional view taken along a broken line L1-L2 in FIG. 15A.

  Next, as shown in FIG. 10, individual electrodes 59 are formed. Specifically, the contact hole 58 is filled with the Ag paste by screen printing using Ag paste, the individual electrodes are printed, and then heated at 140 [° C.] for 30 [minutes]. In addition to forming electrodes in the holes, individual electrodes 59 were formed.

  As a result, the active matrix circuit board shown in FIG. 10 was produced. The formed individual electrodes 59 have a rectangular shape of 100 × 100 [μm], and 640 × 480 are formed in a two-dimensional matrix with a pitch of 127 [μm]. The formed individual electrode 59 is connected to the drain electrodes 54 of 640 × 480 TFTs via the electrodes formed in the contact holes.

  The Ag paste used for printing the individual electrode 59 is an ink in which an Ag filler having a size of 0.1 to 1.0 [μm] is dispersed in an organic vehicle made of acrylic resin and butyl carbitol. Is 10 [rpm] and 240 [Pa · s] when measured using a No. 14 rotor in a Brookfield viscometer.

  The screen plate used for printing the individual electrodes 59 is made of stainless steel 500 mesh, and a nylon mesh and a double bias combination are pasted, and the thickness of the emulsion is 10 [μm]. When performing printing, a squeegee with a clearance of 1.5 mm and a rubber hardness of 70 is used, the attack angle is 70 degrees, and the printing speed is 80 mm / s.

  The active matrix circuit board in this embodiment forms electrodes in contact holes by the same method as in the fifth embodiment. For this reason, it becomes possible to make it finer than the contact hole formed by the conventional screen printing method. As a result, it is possible to achieve miniaturization and higher integration than an active matrix circuit board manufactured by a conventional printing method. Further, since the contact hole is formed by screen printing, it can be manufactured at a lower cost and in a shorter time than when an active matrix circuit board is manufactured by a photolithography method. In particular, in the present embodiment, since the printing of the individual electrodes and the filling of the contact holes are performed simultaneously, the active matrix substrate can be manufactured at a lower cost.

  In the present embodiment, as in the fifth embodiment, contact hole filling and individual electrode printing are performed simultaneously. However, as shown in the fourth embodiment, contact holes are formed. After forming a via hole by embedding a conductive material in the contact hole by a method such as an electrolytic plating method, an electroless plating method, a screen printing method, a gravure offset printing method, a dispenser method, an ink jet method, or photolithography, Individual electrodes may be formed.

In this embodiment mode, a-Si is used as the semiconductor material for the semiconductor layer 56. In addition, oxide semiconductors such as poly-Si, IGZO, ZnO, and Cu ₂ O, pentacene, polythiophene, and triarylamine are used. An organic semiconductor such as a high molecular compound can be used. In this embodiment, the TFT is described as the switching element, but a transistor such as SIT or a diode may be used. In this embodiment mode, the TFT electrode is formed by a photolithography method. However, other printing methods such as a screen printing method, a gravure offset printing method, an ink jet method, and a dispenser method are used. Thus, it is possible to manufacture an active matrix circuit board at a lower cost. In such a printing method, it is possible to use metals, alloys such as Ag, Au, Cr, Cu, and Pt, conductive pastes such as carbon, and conductive ink as materials. In each printing method, It is possible to use the conductive paste and the conductive ink by adjusting the viscosity to a suitable level.

In this embodiment, SiO ₂ is used as the gate insulating film 53 of the TFT. However, other than this, an inorganic insulating film such as SiON or Si ₃ N ₄ or a polymer such as parylene, polyimide, or polyvinylphenol. It is also possible to use a resin.

  In particular, when the electrode material and the gate insulating film are formed of a polymer material, the entire process of the active matrix circuit board can be formed by a printing method, and the active matrix circuit board can be manufactured at a very low cost. Become.

[Seventh Embodiment]
Next, a seventh embodiment will be described. The present embodiment is an image display device according to the present invention.

  Specifically, a liquid crystal display element is formed as an image display element using the active matrix circuit board manufactured in the sixth embodiment.

  The image display apparatus according to the present embodiment will be described with reference to FIG.

  A UV curable epoxy resin is applied on the drive circuit of the active matrix circuit board manufactured in the sixth embodiment by a blade method, and then cured by UV irradiation to form the upper protective film 61. The upper protective film 63 functions not only as a barrier layer of the active matrix circuit board but also as a planarization layer of the active matrix circuit board.

  Next, an alignment film 64 made of soluble polyimide is formed on the formed upper protective film 63. Specifically, soluble polyimide was applied on the upper protective film 63 and heated at 110 [° C.] to evaporate the solvent and form the alignment film 64.

  Next, an ITO film is formed on the counter substrate 65 made of polycarbonate by sputtering, a photoresist is applied onto the ITO film, prebaked, and then exposed and developed by an exposure apparatus to form a resist pattern. Thereafter, the transparent common electrode 66 made of ITO is formed by removing the ITO film on which the resist pattern is not formed by etching by RIE or the like. Thereafter, an alignment film 67 made of soluble polyimide was formed on the transparent common electrode 66 by the same method as described above.

  Thereafter, seal bonding was performed in a state where a gap was provided so that the alignment film 67 on the counter substrate 65 and the alignment film 64 on the active matrix circuit substrate faced each other. Thereafter, a TN liquid crystal serving as the display layer 68 is sealed in a gap formed by the two substrates, thereby forming a reflective liquid crystal display device.

  This liquid crystal display device is driven by a drive circuit in an active matrix circuit board, and has almost the same image quality as a reflective liquid crystal display device formed by a photolithography method.

  The image display device in this embodiment mode can be manufactured at a very low cost compared to a case where a fine contact hole is formed by a screen printing method, compared with a case where the image display device is manufactured by a photolithography method.

  In the present embodiment, the liquid crystal display element is used as the image display device. However, in addition to this, an electroluminescence element, an electrophoretic element, a toner display, an electrowetting element, an electrochromic element, and the like. Can be used.

[Eighth Embodiment]
Next, an eighth embodiment will be described. This embodiment is a multilayer wiring board and a method for forming a multilayer wiring board according to the present invention, and has a structure in which a part of a contact hole is filled with an insulating material.

  Based on FIG. 17, the structure of the multilayer wiring board in this Embodiment is demonstrated. FIG. 17A is a top view of the multilayer wiring board according to the present embodiment, and FIG. 17B is a multilayer wiring board according to the present embodiment cut along the broken line M1-M2 in FIG. FIG.

  The lower electrodes 72 of the multilayer wiring board in the present embodiment are formed on the board 71, extend in the left-right direction on the paper surface in FIG. 17A, and 640 pieces in a vertical direction of 127 [μm] pitch. The lower electrode 72 is formed. An insulating film 74 is formed on the lower electrode 72, and 640 × 480 contact holes are formed in the insulating film 74 so that the surface of the lower electrode 72 is exposed. The shape of the contact hole is a rhombus having a width of about 20 to 40 [μm]. For some contact holes, an insulating material mainly composed of polyvinylphenol resin is filled to form a filled insulating layer 75, and for other contact holes, Ni is deposited by electrolytic plating and filled. By doing so, a via hole 76 is formed. Of the 640 × 480 upper electrodes 77 formed on the insulating film 74, the one having the via hole 76 formed in the contact hole is connected to the lower electrode 72.

  Such a configuration is effective when connecting an arbitrary upper electrode 77 and lower electrode 72.

  Based on FIG. 18 and FIG. 19, the manufacturing method of the multilayer wiring board in this Embodiment is demonstrated.

  First, as shown in FIG. 18 (a), an Ag paste is printed on a substrate 71 made of PET by a screen printing method, and cured at 140 [° C.] and 30 [min], thereby forming a lower portion. An electrode 72 was formed. The lower electrodes 72 extend in the left-right direction in the drawing, and are formed in a length of 640 with a pitch of 127 [μm] perpendicular to the paper surface. The line width of the lower electrode 72 is 60 [μm]. The Ag paste used for printing is an ink in which an Ag filler having a size of 0.1 to 1.0 [μm] is dispersed in an organic vehicle composed of an acrylic resin and butyl carbitol. The viscosity is measured using a Brookfield viscometer. When measured using a No. 14 rotor, 10 [rpm] and 240 [Pa · s].

  The screen plate used for printing the lower electrode 72 is made of stainless steel 500 mesh, a nylon mesh and a double bias combination are pasted, and the thickness of the emulsion is 10 [μm]. When performing printing, a squeegee with a clearance of 1.5 mm and a rubber hardness of 70 is used, the attack angle is 70 degrees, and the printing speed is 80 mm / s. An alignment mark for alignment is also formed around the lower electrode 72 at the same time.

  Next, as shown in FIG. 18B, 640 × 480 contact holes 73 arranged in a two-dimensional matrix are formed on the lower electrode 32 by the same method as in the first embodiment. Thus, the insulating film 74 is formed by printing the insulating paste by screen printing and curing it at 120 [° C.] and 30 [min]. In addition, in order to form 640 × 480 contact holes 73 on the lower electrode 72, alignment is performed by using an alignment mark formed simultaneously with the formation of the lower electrode 72 and an alignment mark formed in advance on the screen plate. After performing, the insulating paste is printed. At this time, the alignment mark formed on the screen plate is also transferred onto the substrate 71.

  Next, as shown in FIG. 18C, for the contact hole 73 that does not require electrical connection between the lower electrode 72 and the upper electrode described later, a polyvinylphenol resin is embedded by a dispenser method at 120 [° C.] A filling insulating layer 75 was formed by heating for 30 minutes.

  Next, as shown in FIG. 19A, by depositing Ni into the contact hole 73 in which the filling insulating layer 75 is not formed among the formed contact holes 73 by electrolytic plating, via holes 76 are formed. Form.

  Next, as shown in FIG. 19B, the upper electrode 77 was formed by printing an Ag paste on the via hole 76 by screen printing and curing at 140 [° C.] for 30 minutes. . The formed upper electrode 77 has a line shape with a width of 60 [μm], and is connected to the lower electrode 72 in the contact hole 73 in which the via hole 76 is formed.

  In order to surely form the upper electrode 77 on the predetermined via hole 76, the alignment mark formed simultaneously with the formation of the insulating film 74 and the alignment formed on the screen plate for forming the upper electrode 77 are used. After alignment with the mark, the upper electrode 77 was formed by screen printing.

  The Ag paste, screen plate, printing conditions, etc. used for printing the upper electrode 77 are the same as the conditions for forming the lower electrode 72. When a voltage of 0.01 [V] was applied between the upper electrode 77 and the lower electrode 72 to check the conduction, all the upper electrodes 77 were electrically connected to the lower electrode 72.

  In this embodiment, when the upper electrode 77 is formed in a line shape and is connected to an arbitrary lower electrode 72 via the contact hole 73, the contact hole 73 that normally does not need to be electrically connected is avoided. Although it is necessary to perform wiring of the upper electrode 77, in this embodiment, the filling insulating layer 75 is formed in the contact hole 73 that does not need to be electrically connected, and the filling insulating layer 75 is formed. Even if the upper electrode 77 is formed over the contact hole 73, it is not electrically connected to the lower electrode 72. Therefore, the wiring width of the upper electrode 77 can be increased, and the yield and the operational stability can be improved. You can plan.

  In this embodiment, the case of two-layer wiring has been described. However, by repeating the method in this embodiment, multilayer wiring of three or more layers can be formed.

[Ninth Embodiment]
Next, a ninth embodiment will be described. This embodiment is a multilayer wiring board and a method for forming a multilayer wiring board according to the present invention, and has a structure in which a part of a contact hole is filled with an insulating material.

  Based on FIG. 20, the structure of the multilayer wiring board in this Embodiment is demonstrated. 20A is a top view of the multilayer wiring board in the present embodiment, and FIG. 20B is a multilayer wiring board in the present embodiment cut along the broken line N1-N2 in FIG. 20A. FIG.

  The lower electrode 82 of the multilayer wiring board in the present embodiment is formed on the substrate 81, extends in the left-right direction on the paper surface in FIG. 20A, and has 640 pieces at a pitch of 127 [μm] in the up-down direction. The lower electrode 82 is formed. An insulating film 84 is formed on the lower electrode 82, and 640 × 480 contact holes are formed in the insulating film 84 so that the surface of the lower electrode 82 is exposed. The shape of the contact hole is a rhombus having a width of about 20 to 40 [μm]. Some contact holes are filled with an insulating material mainly composed of polyvinylphenol resin to form a filling insulating layer 85, and other contact holes are filled with a metal material at the same time as the upper electrode is formed. The As a result, of the 640 × 480 upper electrodes 86 formed on the insulating film 84, those in which the filling insulating layer 85 is not formed in the contact holes are connected to the lower electrode 82.

  Such a configuration is effective in connecting an arbitrary upper electrode 86 and lower electrode 82.

  Based on FIG. 21, the manufacturing method of the multilayer wiring board in this Embodiment is demonstrated.

  First, as shown in FIG. 21 (a), an Ag paste is printed on a substrate 81 made of PET by a screen printing method, and cured at 140 [° C.] and 30 [min], thereby forming a lower portion. An electrode 82 was formed. The lower electrodes 82 extend in the left-right direction in the drawing, and are formed at 640 pieces with a pitch of 127 [μm] in the direction perpendicular to the paper surface. The line width of the lower electrode 82 is 60 [μm]. The Ag paste used for printing is an ink in which an Ag filler having a size of 0.1 to 1.0 [μm] is dispersed in an organic vehicle composed of an acrylic resin and butyl carbitol. The viscosity is measured using a Brookfield viscometer. When measured using a No. 14 rotor, 10 [rpm] and 240 [Pa · s].

  The screen plate used for printing of the lower electrode 82 is made of stainless steel 500 mesh, a nylon mesh and a double bias combination, and the emulsion thickness is 10 [μm]. When performing printing, a squeegee with a clearance of 1.5 mm and a rubber hardness of 70 is used, the attack angle is 70 degrees, and the printing speed is 80 mm / s. An alignment mark for alignment is also formed around the lower electrode 82 at the same time.

  Next, as shown in FIG. 21B, 640 × 480 contact holes 83 arranged in a two-dimensional matrix are formed on the lower electrode 82 by the same method as in the first embodiment. As described above, the insulating paste 84 is printed by screen printing and cured at 120 [° C.] and 30 [min] to form the insulating film 84. In order to form 640 × 480 contact holes on the lower electrode 82, alignment is performed by using the alignment mark formed at the same time when the lower electrode 82 is formed and the alignment mark formed in advance on the screen plate. After that, the insulating paste is printed. At this time, alignment marks formed on the screen plate are also transferred onto the substrate 81.

  Next, as shown in FIG. 21 (c), for the contact hole 83 that does not require electrical connection between the lower electrode 82 and the upper electrode, which will be described later, a polyvinylphenol resin is embedded by a dispenser method at 120 [° C.] The filling insulating layer 85 was formed by heating for 30 minutes.

  Next, as shown in FIG. 21 (d), an Ag paste is printed by a screen printing method and cured at 140 [° C.] for 30 [minutes], whereby the contact without the filling insulating layer 85 is formed. An Ag paste is embedded in the hole 83 and an upper electrode 86 is formed. The formed upper electrode 86 has a line shape with a width of 60 [μm], and is connected to the lower electrode 82 in the contact hole 83 in which the filling insulating layer 85 is not formed.

  In order to ensure electrical connection between the upper electrode 86 and the predetermined lower electrode 82, an alignment mark formed simultaneously with the formation of the insulating film 84 and a screen plate for forming the upper electrode 86 are used. After alignment with the formed alignment mark, the contact hole 83 in which the filling insulating layer 85 is not formed and the upper electrode 86 are formed by screen printing.

  The Ag paste, screen plate, printing conditions, and the like used for printing the upper electrode 86 are the same as the conditions for forming the lower electrode 82. When a voltage of 0.01 [V] was applied between the upper electrode 86 and the lower electrode 82 to examine conduction, all the upper electrodes 86 were electrically connected to the lower electrode 82.

  In the present embodiment, when the upper electrode 86 is formed in a line and is connected to an arbitrary lower electrode 82 via the contact hole 83, the contact hole 83 that normally does not need to be electrically connected is avoided. Although the upper electrode 86 needs to be wired, in this embodiment, the filling insulating layer 85 is formed in the contact hole 83 that does not need to be electrically connected. The filling insulating layer 85 is formed. Even if the upper electrode 86 is formed on the contact hole 73, it is not electrically connected to the lower electrode 82. Therefore, the wiring width of the upper electrode 86 can be increased, and the yield and the operational stability can be improved. Can be planned.

  In this embodiment, the upper electrode 86 is formed by a screen printing method using an Ag paste. However, the upper electrode 86 is made of a material or a formation method capable of simultaneously filling the contact hole 83 and forming the upper electrode 86. Applicable if available. Specifically, as a material, metals and alloys such as Al, Ag, Au, Cr, Cu, and Pt, conductive paste such as carbon, and conductive ink can be used. In this case, the viscosity is suitable for printing. It can be used by adjusting. As for the forming method, a gravure offset printing method, a dispenser method, an ink jet method, or the like can be used. Note that the screen printing method described in the present embodiment is suitable for forming a thick film as compared with other printing methods. Therefore, when simultaneously filling the contact hole 83 and forming the upper electrode 86, Is suitable.

  In this embodiment, the case of two-layer wiring has been described. However, by repeating the method in this embodiment, multilayer wiring of three or more layers can be formed. Further, since there is no need to form a via hole, it can be manufactured at a lower cost.

  As mentioned above, although the form which concerns on implementation of this invention was demonstrated, the said content does not limit the content of invention.

Top view of the screen plate in the first embodiment Process drawing by screen printing method in the first embodiment The top view of the board | substrate with which the through hole was formed in 1st Embodiment Metal micrograph of substrate on which through hole is formed in the first embodiment The figure which shows the surface shape of the interlayer insulation film in 1st Embodiment Schematic diagram of circuit board in the fourth embodiment Manufacturing process diagram of circuit board in fourth embodiment Schematic diagram of a circuit board in the fifth embodiment Manufacturing process diagram of circuit board in fifth embodiment Schematic diagram of active matrix circuit board according to sixth embodiment Process diagram of active matrix circuit board in sixth embodiment (1) Process diagram of active matrix circuit board in sixth embodiment (2) Process diagram of active matrix circuit board in sixth embodiment (3) Process diagram of active matrix circuit board in sixth embodiment (4) Process diagram of active matrix circuit board in sixth embodiment (5) Sectional drawing of the image display apparatus in 7th Embodiment Schematic diagram of a circuit board in the eighth embodiment Manufacturing Process Diagram of Circuit Board in Eighth Embodiment (1) Manufacturing Process Diagram of Circuit Board in Eighth Embodiment (2) Schematic diagram of a circuit board in the ninth embodiment Manufacturing process diagram of circuit board in ninth embodiment

Explanation of symbols

11 Screen plate 12 Paste discharge area 12a, 12b, 12c, 12d Paste discharge area 21 Substrate 25a, 25b, 25c, 25d Pattern of discharged insulating paste 26 Contact hole 26a, 26b, 26c Contact hole 31 Substrate 32 Lower electrode 33 Contact hole 34 Insulating film (interlayer insulating film)
35 Via hole 36 Upper electrode

Claims (16)

In a method for forming a circuit board comprising a multilayer wiring, wherein the contact holes for connecting the lower electrode and the upper electrode via the interlayer insulating film are two-dimensionally arranged in a matrix,
A screen plate having paste discharge areas of a predetermined shape arranged two-dimensionally, and insulating paste discharged from three or more paste discharge areas adjacent to each other in the screen plate are joined two-dimensionally by sagging A printing step for performing printing so that the contact hole is formed,
A curing step of curing the printed insulating paste;
A method for forming a circuit board, comprising:   2. The circuit board forming method according to claim 1, wherein, in the printing step, the three or more adjacent paste discharge regions are paste discharge regions closest to one another. 3.   Paste discharge areas in the screen plate used in the printing process are two-dimensionally arranged at equal intervals, and the contact holes are formed by insulating paste discharged from the four nearest paste discharge areas. The method for forming a circuit board according to claim 1, wherein the circuit board is formed. In a method for forming a circuit board comprising a multilayer wiring, wherein the contact holes for connecting the lower electrode and the upper electrode via the interlayer insulating film are two-dimensionally arranged in a matrix,
In the Brookfield viscometer, an insulating paste with a viscosity measured using a No. 14 rotor of 50 [rpm] and 30 to 100 [Pa · s] is used, and the discharge area of the rectangular or circular paste is a matrix. A printing step of printing the insulating paste on the circuit board by a screen plate that is two-dimensionally arranged and has an interval between the adjacent discharge regions adjacent to each other of 20 to 50 [μm]. ,
A curing step of curing the printed insulating paste;
A method for forming a circuit board, comprising: For some contact holes formed by the curing step, an insulating material filling step for filling the contact holes with an insulating paste;
A second curing step of curing the filled insulating paste to form a filled insulating layer;
The method for forming a circuit board according to claim 1, comprising: After the curing step in the method for forming an interlayer insulating film according to claim 1 to 4, a connection electrode forming step of filling a contact hole formed of a cured insulating paste with a conductive material;
A method for manufacturing a circuit board, comprising: After the second curing step in the method for forming an interlayer insulating film according to claim 5, a connection electrode forming step of filling a conductive material into a contact hole formed by a cured insulating paste;
A method for manufacturing a circuit board, comprising: In a circuit board composed of multilayer wiring, in which contact holes for connecting the lower electrode and the upper electrode through an interlayer insulating film are two-dimensionally arranged in a matrix,
The interlayer insulating film, there is formed by screen printing using a screen plate having a paste ejection exit area of a predetermined shape are arranged two-dimensionally,
Among the insulating pastes discharged from the paste discharge region, the contact holes are formed by two-dimensionally joining the insulating pastes discharged simultaneously from three or more adjacent paste discharge regions. A circuit board characterized by. Three or more paste discharge region before Symbol proximity, the circuit board according to claim 8, characterized in that a paste ejection region that is closest to each other.   The paste ejection areas are two-dimensionally arranged at equal intervals in the screen plate, and the contact holes are formed by insulating paste ejected from four closest paste ejection areas. The circuit board according to 8 or 9. An interval between the adjacent discharge areas adjacent to each other in the screen plate is 20 to 50 [μm],
The insulating paste has a viscosity of 50 [rpm] measured using a No. 14 rotor in a Brookfield viscometer, and is 30 to 100 [Pa · s]. Circuit board as described in.   12. The circuit board according to claim 8, wherein a predetermined insulating hole is a filling insulating layer formed by filling an insulating material.   13. The circuit board according to claim 8, wherein the upper electrode and the connection electrode formed by filling the contact hole are formed at the same time.   13. The circuit board according to claim 8, wherein the connection electrode formed by embedding the upper electrode and the contact hole is formed by a printing method.   15. The active matrix circuit board according to claim 8, wherein the electrical wiring in the circuit board according to claim 8 is electrically connected to a two-dimensionally arranged transistor or diode.   An image display device, wherein an image display element is laminated on the active matrix circuit board according to claim 15.