JP2009177108A - Method of forming conductor pattern, and conductor pattern - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of forming a conductor pattern, which can raise the yield and can form a conductor pattern of low specific resistance by a few processes. <P>SOLUTION: In the forming method of a conductor pattern 3, a conductive paste 2 is printed in a predetermined shape on a base 1, and then is pressed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a conductor pattern forming method and a conductor pattern which are used not only for forming a normal circuit pattern of a printed wiring board but also for forming an electromagnetic wave shield pattern.

  Conventionally, a conductor pattern as a circuit pattern of a printed wiring board is formed using a subtractive method, an additive method, a semi-additive method, or the like. The conductor pattern formed in this way has high conductivity, but all of the above methods involve a large number of steps and are troublesome.

  Therefore, in order to reduce the number of steps and save labor, a conductive pattern is formed by printing a conductive paste in a predetermined shape. However, the conductor pattern thus formed has a high specific resistance and may have a low conductivity.

Therefore, in recent years, a method has been developed to form a conductive pattern with low specific resistance by printing a conductive paste containing an electroless plating catalyst and then subjecting it to electroless plating to form a metal layer. (For example, refer to Patent Document 1).
JP 11-170420 A

  However, although the method for forming a conductor pattern as described above, which has been developed in recent years, has a small number of processes, there is a problem in that a plating deposition defect due to bubbles occurs when performing electroless plating treatment, resulting in a low yield.

  The present invention has been made in view of the above points, and provides a conductor pattern forming method and a conductor pattern that can increase the yield and can easily form a conductor pattern having a low specific resistance with a small number of steps. It is intended to provide.

  The method for forming a conductor pattern according to claim 1 of the present invention is characterized in that a conductive paste 2 is printed in a predetermined shape on a substrate 1 and then pressed.

  The invention according to claim 2 is characterized in that, in claim 1, pressing is performed by gas pressure.

  The invention according to claim 3 is the invention according to claim 1, wherein the elastic sheet 6 is overlaid on the surface of the substrate 1 on which the conductive paste 2 is printed, and the space between the printed surface and the elastic sheet 6 is reduced to reduce the elastic sheet 6. The printing surface is pressed by a gas or liquid pressure.

  The conductor pattern according to claim 4 of the present invention is formed by pressing the conductive paste 2 printed in a predetermined shape on the base material 1.

  The invention according to claim 5 is characterized in that, in claim 4, it is formed by being pressed by the pressure of gas.

  The invention according to claim 6 is the elastic sheet according to claim 4, wherein the elastic sheet 6 is superimposed on the surface of the substrate 1 on which the conductive paste 2 is printed, and the space between the printed surface and the elastic sheet 6 is reduced in pressure. 6, the printing surface is formed by being pressed by gas or liquid pressure.

  According to the method for forming a conductor pattern according to claim 1 of the present invention, the yield can be increased and a conductor pattern having a low specific resistance can be easily formed with a small number of steps.

  According to the second aspect of the invention, the yield can be increased and a conductor pattern having a low specific resistance can be easily formed with a small number of steps. And since it is not based on a flat plate press, it can prevent that the line width of a conductor pattern spreads.

  According to the third aspect of the invention, the yield can be increased, and a conductor pattern having a low specific resistance can be easily formed with a small number of steps. And since it is not based on a flat plate press, it can prevent that the line width of a conductor pattern spreads.

  According to the conductor pattern of claim 4 of the present invention, the specific resistance is lower than that of a conventional conductor pattern formed of a conductive paste.

  According to the invention which concerns on Claim 5, compared with the conventional conductor pattern formed with the electrically conductive paste, a specific resistance is low.

  According to the invention which concerns on Claim 6, compared with the conventional conductor pattern formed with the electrically conductive paste, a specific resistance is low.

  Embodiments of the present invention will be described below.

  In the present invention, the substrate 1 is not particularly limited as long as it has an insulating property. For example, in addition to a polyethylene terephthalate film (PET film), an acrylic resin typified by polymethyl methacrylate, polyethylene Polyester resins such as terephthalate, polybutylene terephthalate, polyethylene naphthalate, norbornene resins represented by the trade name “Arton” manufactured by JSR Corporation, and olefin maleimide resins represented by the product number “TI-160” manufactured by Tosoh Corporation A sheet-like or plate-like material such as an organic resin substrate formed of glass, a glass substrate formed of glass, an epoxy resin substrate described in JP-A-08-148829, etc. Can be used.

  The conductive paste 2 was prepared by blending metal powder, metal oxide powder such as antimony-tin oxide and indium-tin oxide, graphite, carbon black, thermoplastic resin, additive, solvent and the like. Things can be used. As the metal powder, it is possible to use silver powder, copper powder, nickel powder, aluminum powder, iron powder, magnesium powder and alloy powders thereof or those selected from those powders coated with one or more layers of different metals. It is preferable that this compounding quantity is 0-99 mass% with respect to the electroconductive paste 2 whole quantity. Moreover, it is preferable that the compounding quantity of carbon black and a graphite is 0-99 mass%. At least one of metal powder, carbon black, and graphite is used. Examples of the thermoplastic resin include vinyl resins, polyester resins, acrylic resins, derivatives of these resins containing -COC-skeleton, -COO-skeleton, etc., and cellulose derivatives such as carboxymethylcellulose, acetylcellulose, and cellulose acetate butyrate. It is preferable that this compounding quantity is 0.1-20 mass%. Moreover, as an additive, anti-foaming agents and leveling agents such as “BYK333 (silicone oil)” manufactured by Big Chemie Japan Co., Ltd. can be used, and the blending amount is preferably 0 to 10% by mass. Examples of the solvent include methanol, ethanol, isopropyl alcohol (IPA), methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), toluene, ethyl acetate, cyclohexanone, xylene, diethylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether, 1- (2-methoxy-2-methylethoxy) -2-propanol, propylene glycol monomethyl ether acetate and water can be used alone or as a mixed solvent mixed in an arbitrary ratio. It is preferable that a compounding quantity is 0.1-50 mass%.

  In forming the conductor pattern 3, first, the conductive paste 2 is printed in a predetermined shape on the surface of the substrate 1 as shown in FIG. Here, the shape to be printed on the substrate 1 is not particularly limited, and examples thereof include a lattice shape or a mesh shape (mesh shape) as shown in FIG. Thus, the base material 1 on which the lattice-like or mesh-like conductor pattern 3 is formed can be used as an electromagnetic wave shielding material for a plasma display or the like. That is, the grid-like or mesh-like conductor pattern 3 in this case is formed as an electromagnetic wave shield pattern. The printing method is not particularly limited, and for example, screen printing, gravure printing, offset printing, and the like can be used.

Thereafter, the conductive paste 2 printed on the surface of the substrate 1 is dried by heating under conditions of 50 to 150 ° C. and 0.1 to 180 minutes, and this is heated and pressurized as shown in FIG. By pressing using 4, a conductor pattern 3 as shown in FIG. 1C can be formed. The contact pattern 3 formed in this way is compressed by a press to increase the contact area between conductive fine particles such as metal powder, so that it is compared with the conventional conductor pattern 3 formed from the conductive paste 2. Thus, the specific resistance is lowered and the conductivity is increased. Here, the pressing is preferably performed under conditions of 50 to 150 ° C., 0.01 to 200 kgf / cm ² (0.98 kPa to 19.6 MPa), and 0.1 to 180 minutes. In addition, after the heating and pressurization, rapid cooling with water cooling or the like while maintaining the pressure, for example, cooling from 110 ° C. to 40 ° C. in 30 minutes is also effective in maintaining the compressed state of the conductive paste 2. In the case of pressing, a release sheet 5 may be interposed between the substrate 1 on which the conductive paste 2 is printed and the heating and pressing apparatus 4 as shown in FIG. As the release sheet 5, a polyester film, a polyester film coated with a release agent such as a silicone resin and provided with a release agent layer, a known polarizing plate, or the like can be used.

FIG. 3 shows another example of the embodiment of the present invention. In this example, after the conductive paste 2 is first printed in a predetermined shape on the surface of the substrate 1 as in FIG. This is heated and dried. And when this base material 1 is put in the autoclave 7 as shown in FIG. 3 and pressed by the pressure of a gas such as air or water vapor, the same conductor pattern 3 as in FIG. 1C can be formed. The conductor pattern 3 formed in this way is compressed by pressing with gas pressure, so that the contact area between conductive fine particles such as metal powder increases, so that the conventional conductor formed with the conductive paste 2 Compared with the pattern 3, the specific resistance is low and the conductivity is high. Moreover, in the flat plate press using the heating and pressing apparatus 4 shown in FIG. 1B, the conductor pattern 3 is compressed in a direction perpendicular to the surface of the substrate 1, so that the line width may be increased. 3 is a press by gas pressure, and the conductor pattern 3 is not compressed only in a certain direction, so that it is possible to prevent the line width from expanding. Here, as the autoclave 7, a normal pressure vessel equipped with a pressure gauge, a thermometer, or the like can be used. Moreover, it is preferable to perform the press by the pressure of gas on the conditions of 50-150 degreeC, 0.01-200 kgf / cm < ² > (0.98kPa-19.6MPa), 0.1-180 minutes. In addition, after the heating and pressurization, rapid cooling with water cooling or the like while maintaining the pressure, for example, cooling from 110 ° C. to 40 ° C. in 30 minutes is also effective in maintaining the compressed state of the conductive paste 2.

FIG. 4 shows still another example of the embodiment of the present invention. In this example, after the conductive paste 2 is first printed in a predetermined shape on the surface of the substrate 1 as in FIG. 1 (a). This is heated and dried. Then, as shown in FIG. 4, an elastic sheet 6 such as a silicon rubber sheet is placed on the surface of the substrate 1 on which the conductive paste 2 is printed, and this is placed in a gas such as air or a liquid such as water. However, in order to prevent gas or liquid from entering between the printing surface and the elastic sheet 6, the gap between the base material 1 and the elastic sheet 6 is preliminarily packed except for an opening (not shown) required at the time of decompression described later. It is sealed with etc. Next, a pressure of gas or liquid is applied to the printing surface via the elastic sheet 6 by reducing the pressure between the printing surface and the elastic sheet 6 by connecting a decompression means such as a vacuum pump to the opening. When pressed by 4), the same conductor pattern 3 as in FIG. 1C can be formed. Since the conductive pattern 3 formed in this way is compressed by pressing with a gas or liquid pressure, the contact area between the conductive fine particles such as metal powder increases, so that the conventional conductive pattern 3 formed with the conductive paste 2 is used. Compared with the conductor pattern 3, the specific resistance is lowered and the conductivity is increased. Moreover, in the flat plate press using the heating and pressing apparatus 4 shown in FIG. 1B, the conductor pattern 3 is compressed in a direction perpendicular to the surface of the substrate 1, so that the line width may be increased. 4 is a press by the pressure of gas or liquid, and since the conductor pattern 3 is not compressed only in a certain direction, it is possible to prevent the line width from expanding. Here, it is preferable that the pressure reduction degree (vacuum degree) between the said printing surface and the elastic sheet 6 is 0-1.013 * 10 < ⁵ > Pa, and the press by the pressure of gas or a liquid is 40-200 degreeC, 0.01 It is preferable to carry out under the conditions of ~ 200 kgf / cm ² (0.98 kPa to 19.6 MPa) and 0.1 to 180 minutes.

  Thus, in the present invention, since it is not necessary to perform electroless plating or the like, the yield can be increased as compared with the conventional method of forming the conductor pattern 3. In the present invention, since the conductor pattern 3 is formed only through the printing process and the pressing process, the number of processes can be reduced and labor can be saved as compared with the conventional method of forming the conductor pattern 3. In addition, the conductor pattern 3 having a low specific resistance can be easily formed by pressing in such a small number of steps.

  In addition, although illustration is abbreviate | omitted, you may make it coat | cover the surface in which the conductor pattern 3 of the base material 1 was formed with a cover sheet. As this cover sheet, what was formed with ethylene vinyl acetate copolymer (EVA), amorphous PET (PET-G), PET with a transparent adhesive layer, etc. can be used.

  Hereinafter, the present invention will be specifically described by way of examples.

  A PET film was used as the substrate 1.

  As the conductive paste 2, the following three types # 1 to # 3 were used.

  That is, as the conductive paste 2 of # 1, 5% by mass of “cellulose acetate butyrate CAB-551-0.2” manufactured by EASTMAN, 3% by mass of “carbon black # 2350” manufactured by Mitsubishi Chemical, manufactured by Mitsui Metal Mine Co., Ltd. What was prepared by blending 80% by mass of “silver powder 3050HD”, 10% by mass of methyl isobutyl ketone and 2% by mass of diethylene glycol monoethyl ether acetate was used.

  In addition, as the conductive paste 2 of # 2, 5% by mass of “cellulose acetate butyrate CAB-551-0.2” manufactured by EASTMAN, 3% by mass of “carbon black # 2350” manufactured by Mitsubishi Chemical, “manufactured by DOWA Hightech” Silver powder AG-SMDK-101 "was prepared by blending 80% by mass, methyl isobutyl ketone 10% by mass, and diethylene glycol monoethyl ether acetate 2% by mass.

  Moreover, as the conductive paste 2 of # 3, “AF5200E” manufactured by Taiyo Ink Manufacturing was used.

  First, using the screen printing, as shown in FIG. 5, the conductive paste 2 of # 1 was printed on the surface of the substrate 1 in a rectangular shape (5 mm × 30 mm × 0.1 mm) in plan view.

Thereafter, the # 1 conductive paste 2 printed on the surface of the substrate 1 was dried by heating at 120 ° C. for 30 minutes (Comparative Example 1). The specific resistance at this time was 2.90 × 10 ⁻⁴ Ωcm.

Next, by pressing the base material 1 of Comparative Example 1 at 115 ° C. and 2.54 kgf / cm ² (249 kPa) for 50 minutes using the heating and pressing apparatus 4 as shown in FIG. Formed (Example 1). The specific resistance at this time was 3.23 × 10 ⁻⁵ Ωcm.

Moreover, the base material 1 of the comparative example 1 is put in the autoclave 7 as shown in FIG. 3, and is pressed by air pressure under the conditions of 115 ° C., 6.12 kgf / cm ² (600 kPa), 60 minutes, Conductive pattern 3 was formed (Example 2). The specific resistance at this time was 5.32 × 10 ⁻⁵ Ωcm.

Moreover, the silicon rubber sheet was piled up as the elastic sheet 6 on the printing surface of the base material 1 of Comparative Example 1 as shown in FIG. 4, and this was placed in the atmosphere. And between the said printing surface and the elastic sheet 6 is pressure-reduced so that a pressure reduction degree (vacuum degree) may be 1.013 * 10 < ³ > Pa, 115 degreeC and 2.04 kgf / cm < ² > (200 kPa), 60 minutes conditions The conductor pattern 3 was formed by pressing with the pressure of air (Example 3). The specific resistance at this time was 6.32 × 10 ⁻⁵ Ωcm.

Moreover, the silicon rubber sheet was piled up as the elastic sheet 6 on the printing surface of the base material 1 of Comparative Example 1 as shown in FIG. 4, and this was placed in water. And between the said printing surface and the elastic sheet 6 is pressure-reduced so that a pressure reduction degree (vacuum degree) may be 1.013 * 10 < ³ > Pa, 95 degreeC and 2.04 kgf / cm < ² > (200 kPa), 60 minutes conditions A conductor pattern 3 was formed by pressing with water pressure (Example 4). The specific resistance at this time was 8.99 × 10 ⁻⁵ Ωcm.

  As described above, it is confirmed that the conductive pattern 3 of Examples 1 to 4 after pressing has a lower specific resistance and higher conductivity than the conductive pattern 3 of Comparative Example 1 before pressing.

  Next, the electromagnetic shielding material was manufactured using the base material 1 and the conductive paste 2 of # 2 similar to the above. That is, first, screen printing was used to print # 2 conductive paste 2 on the surface of the substrate 1 in a grid or mesh pattern as shown in FIG. At this time, two types were printed using a screen plate having a line (L) / pitch (P) of 17 μm / 300 μm and 20 μm / 250 μm.

  Thereafter, the # 2 conductive paste 2 printed on the surface of the substrate 1 was heated and dried at 120 ° C. for 30 minutes. This was used as the electromagnetic shielding material of Comparative Examples 2 and 3.

Next, the conductor pattern 3 was formed by pressing the electromagnetic wave shielding material of Comparative Examples 2 and 3 using the heating and pressing device 4 at 115 ° C. and 2.54 kgf / cm ² (249 kPa) for 50 minutes. This was used as the electromagnetic shielding material of Examples 5 and 6.

Moreover, the electromagnetic wave shielding material of the comparative example 2 was put in the autoclave 7, and the conductor pattern 3 was formed by pressing by 115 degreeC, 6.12 kgf / cm < ² > (600 kPa), and the pressure of air for 60 minutes. did. This was used as the electromagnetic shielding material of Example 7.

Further, a silicon rubber sheet was stacked as the elastic sheet 6 on the printed surface of the electromagnetic shielding material of Comparative Example 2, and this was placed in the atmosphere. And between the said printing surface and the elastic sheet 6 is pressure-reduced so that a pressure reduction degree (vacuum degree) may be 1.013 * 10 < ³ > Pa, 115 degreeC and 2.04 kgf / cm < ² > (200 kPa), 60 minutes conditions The conductor pattern 3 was formed by pressing with the pressure of air. This was used as the electromagnetic shielding material of Example 8.

Moreover, the silicon rubber sheet was piled up as the elastic sheet 6 on the printing surface of the electromagnetic wave shielding material of Comparative Example 2, and this was placed in water. And between the said printing surface and the elastic sheet 6 is pressure-reduced so that a pressure reduction degree (vacuum degree) may be 1.013 * 10 < ³ > Pa, 95 degreeC and 2.04 kgf / cm < ² > (200 kPa) on the conditions for 60 minutes. The conductor pattern 3 was formed by pressing with water pressure. This was used as the electromagnetic shielding material of Example 9.

  Next, the electromagnetic shielding material was manufactured using the base material 1 and the conductive paste 2 of # 3 similar to the above. That is, first, screen printing was used to print the # 3 conductive paste 2 on the surface of the substrate 1 in a grid or mesh pattern as shown in FIG. At this time, printing was performed using a screen plate having a line (L) / pitch (P) of 17 μm / 300 μm.

  Thereafter, the # 3 conductive paste 2 printed on the surface of the substrate 1 was heated and dried at 120 ° C. for 30 minutes. This was used as the electromagnetic shielding material of Comparative Example 4.

Next, conductor pattern 3 was formed by pressing the electromagnetic shielding material of Comparative Example 4 at 115 ° C. and 2.54 kgf / cm ² (249 kPa) for 50 minutes using heating and pressing device 4. This was used as the electromagnetic shielding material of Example 10.

  And the surface resistance of each electromagnetic wave shielding material was measured. Further, the shielding performance was measured for each electromagnetic wave shielding material by changing the frequency. These results are shown in the following [Table 1] and FIGS. In addition, the following [Table 1] also shows measured values of the vertical line width / horizontal line width of the conductor pattern 3 before and after pressing.

  As seen in [Table 1] above, the electromagnetic shielding materials of Examples 5 to 10 after pressing have lower surface resistance and higher conductivity than the electromagnetic shielding materials of Comparative Examples 2 and 3 before pressing. Is confirmed. Moreover, as seen in the above [Table 1] and FIGS. 6 to 11, the electromagnetic shielding materials of Examples 5 to 10 after pressing have a shielding effect compared to the electromagnetic shielding materials of Comparative Examples 2 and 3 before pressing. In particular, it is confirmed that the difference between the two increases as the frequency increases.

An example of the process of forming a conductor pattern is shown, (a)-(c) is sectional drawing. It is a top view which expands and shows a part of base material in which the conductor pattern was formed. It is sectional drawing which shows another example of the process of forming a conductor pattern. It is sectional drawing which shows another example of the process of forming a conductor pattern. It is a top view which shows the base material in which the conductor pattern of Example 1 and Comparative Example 1 was formed. It is a graph which shows the relationship between a frequency and a shielding effect about the electromagnetic wave shielding material of Example 5 and Comparative Example 2 whose line / pitch is 17 μm / 300 μm. It is a graph which shows the relationship between a frequency and a shielding effect about the electromagnetic wave shielding material of Example 6 and Comparative Example 3 whose line / pitch is 20 μm / 250 μm. It is a graph which shows the relationship between a frequency and a shielding effect about the electromagnetic wave shielding material of Example 7 and Comparative Example 2 whose line / pitch is 17 μm / 300 μm. It is a graph which shows the relationship between a frequency and a shielding effect about the electromagnetic wave shielding material of Example 8 and Comparative Example 2 whose line / pitch is 17 μm / 300 μm. It is a graph which shows the relationship between a frequency and a shielding effect about the electromagnetic wave shielding material of Example 9 and Comparative Example 2 whose line / pitch is 17 μm / 300 μm. It is a graph which shows the relationship between a frequency and a shielding effect about the electromagnetic wave shielding material of Example 10 and Comparative Example 4 whose line / pitch is 17 μm / 300 μm.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base material 2 Conductive paste 3 Conductor pattern 6 Elastic sheet

Claims (6)

  A method for forming a conductor pattern, comprising: printing a conductive paste on a substrate in a predetermined shape, and then pressing the paste.   2. The method for forming a conductor pattern according to claim 1, wherein pressing is performed by gas pressure.   It is characterized in that an elastic sheet is superimposed on the surface of the base material on which the conductive paste is printed, and the printing surface is pressed by gas or liquid pressure through the elastic sheet by reducing the pressure between the printing surface and the elastic sheet. The method for forming a conductor pattern according to claim 1.   A conductive pattern formed by pressing a conductive paste printed in a predetermined shape on a base material.   The conductor pattern according to claim 4, wherein the conductor pattern is formed by being pressed by a gas pressure.   An elastic sheet is superimposed on the surface of the base material on which the conductive paste is printed, and the printed surface is pressed by gas or liquid pressure through the elastic sheet by reducing the pressure between the printed surface and the elastic sheet. The conductor pattern according to claim 4, wherein the conductor pattern is formed.

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