JP2004186556A - Method for forming thick film wiring - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thick film wiring forming method capable of forming thick film wiring of a fine pattern shape having no dirt on a base body. <P>SOLUTION: The thick film wiring forming method comprises a 1st process for padding pattern grooves 2 of an intaglio 1 on which pattern grooves 2 corresponding to a required thick film wiring pattern are formed with conductive paste P, a 2nd process for drying or hardening the conductive paste P padded in the pattern grooves 2 up to hardness by which the paste P can be peeled off from the intaglio 1, a 3rd process for transferring the conductive paste P dried or hardened up to the hardness permitting peeling from the intaglio 1 to an intermediate body 24 having stickiness on its transfer surface, a 4th process for reducing the stickiness of the transfer surface of the intermediate body 24, and a 5th process for re-transferring the conductive paste P transferred to the intermediate body 24 to the base body 30. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for forming a thick film wiring, and particularly to a method suitable for forming a wiring having a fine line width and a relatively large film thickness (10 μm or more) on a substrate.
[0002]
[Prior art]
[Patent Document 1] Japanese Patent No. 3039285 [Patent Document 2] Japanese Patent Application Laid-Open No. 11-154782 [Patent Document 3] Japanese Patent No. 2935852 Recently, with the miniaturization of electronic devices, electronic devices used in devices have been developed. The miniaturization of parts is also progressing. Under such circumstances, even in the pattern of the electronic component, a thick film wiring for the purpose of miniaturizing the wiring constituting the pattern and reducing the line resistance is required. In order to achieve such an object, in Patent Literature 1, a conductive paste is filled in a flexible resin intaglio, and after the paste is dried, an additional conductive paste is refilled in order to compensate for volume absorption due to drying. Repeating the process of re-drying the conductive paste after refilling a plurality of times, forming an adhesive layer on the substrate, bonding the intaglio to the substrate, transferring the conductive paste to the substrate, and baking to obtain thick film wiring Has been proposed.
[0003]
Further, in Patent Document 2, a photocurable conductive paste containing metal powder is embedded in a transparent intaglio groove, and ultraviolet light is irradiated from the intaglio side in a state where the substrate is in contact with the conductive paste in the groove. A reaction is caused to cure the conductive paste and adhere to the substrate.Then, the intaglio is separated from the substrate, the cured conductive paste is transferred to the substrate side, and then the conductive paste is baked to form the thick film wiring on the substrate. There is also proposed a method of forming the same.
[0004]
In any of the above methods, the conductive paste is supplied to the intaglio, the excess conductive paste is scraped off with a doctor or squeegee, and then the conductive paste is directly transferred to the substrate. When a residue (ground stain) occurs, the background stain is also transferred to the substrate as it is. Therefore, in a high-density wiring that requires a narrow pattern pitch, a short circuit failure between patterns has been caused.
[0005]
[Problems to be solved by the invention]
Patent Document 3 proposes a method of printing a fine pattern in which a resist ink filled and cured in an intaglio is once transferred to an intermediate, and then re-transferred to a printing medium. If this method is applied to the printing of a conductive paste, it is possible to transfer only the necessary pattern portion to the substrate while leaving the background of the intaglio in the intermediate.
In this method, it is necessary to irradiate the paste filled in the intaglio with ultraviolet light or the like to make the surface layer part in an incompletely cured state having an adhesive property and to make the other part in a completely cured state. However, when transferring the paste filled in the intaglio to the intermediate, the contact area between the paste and the intaglio is larger than the contact area with the intermediate, so it is not always possible to transfer the paste to the intermediate reliably. And part of the paste may remain in the intaglio. In particular, when the thickness of the conductive paste is 20 μm or more, ultraviolet rays do not penetrate deeply due to the metal powder contained in the conductive paste, and only the surface layer is incompletely cured while the inside is completely cured. Difficult to do. Therefore, even if the method of Patent Document 3 is applied to the printing of the conductive paste, it is difficult to transfer the thick film-like paste from the intaglio to the intermediate.
[0006]
As a method for solving this problem, for example, it is possible to provide an adhesive layer on the surface of the intermediate and transfer the conductive paste to the intermediate based on the difference in the adhesive strength between the intaglio and the intermediate. However, when re-transferring from the intermediate to the substrate, it must be transferred to a substrate having a higher adhesive layer, which increases the stress applied to the conductive paste and the substrate, and causes problems such as damage to wiring patterns and damage to the substrate. May occur.
[0007]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for forming a thick film wiring capable of forming a beautiful pattern of a thick film wiring with no background contamination on a substrate.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 is a method for forming a thick film wiring on a substrate, comprising a pattern of an intaglio having a pattern groove corresponding to a desired pattern of the thick film wiring formed on the surface. A first step of embedding a conductive paste in the groove, a second step of drying or hardening the conductive paste embedded in the pattern groove to a peelable hardness from the intaglio, and a step of drying or hardening to the peelable hardness A third step of transferring the conductive paste from the intaglio to the transfer surface of the intermediate having adhesiveness, a fourth step of reducing the adhesiveness of the transfer surface of the intermediate, and the conductive paste transferred to the intermediate And a fifth step of re-transferring the substrate to a substrate.
[0009]
First, a conductive paste is embedded in an intaglio pattern groove having a pattern groove formed on the surface. This embedding step can be easily performed by, for example, supplying a conductive paste to the surface of the intaglio and scraping off excess conductive paste with a squeegee or the like.
Next, the conductive paste embedded in the pattern groove is subjected to a hardening treatment such as ultraviolet light or heat or a drying treatment to dry or harden the conductive paste to a hardness that can be peeled from the intaglio. At this time, a complicated process of setting only a part of the surface layer of the conductive paste to an incompletely cured state is unnecessary.
Next, the conductive paste dried or hardened to a predetermined hardness is transferred from the intaglio to the intermediate. Since the transfer surface of the intermediate has tackiness, the conductive paste is easily transferred from the intaglio to the intermediate due to the tackiness. At this time, since the conductive paste has already been dried or hardened to a peelable hardness, there is no problem that a part of the paste remains in the intaglio.
After transferring the conductive paste to the intermediate, the adhesiveness of the transfer surface of the intermediate is reduced. As the intermediate, for example, a sheet whose adhesive force changes depending on temperature, a UV release sheet which loses its adhesive force when irradiated with ultraviolet rays, or the like can be used.
After reducing the tackiness of the intermediate, the conductive paste transferred to the intermediate is retransferred to the substrate. At this time, since the intermediate has little adhesiveness, the conductive paste is easily peeled off from the intermediate and transferred to the substrate by the action of the adhesive itself or the adhesive force of the surface of the substrate.
After transferring the conductive paste to the substrate, for example, the substrate is put into a firing furnace and fired integrally, whereby a thick film wiring can be easily formed.
By changing the adhesiveness of the intermediate as described above, the conductive paste in the intaglio can be reliably transferred to the substrate via the intermediate. Even if the conductive paste has a thickness of 20 μm or more, the transfer can be performed. Defects can be eliminated. In addition, problems such as residual conductive paste in the intaglio and transfer of background stains to the substrate can be solved. Further, the stress applied to the conductive paste and the base is small, and damage to the wiring pattern and the base can be reduced.
[0010]
As described in claim 2, the transfer surface of the intermediate has a property that the adhesive force changes depending on the temperature, and the third step is performed at a high adhesive force temperature, and the fourth step is performed at a low adhesive force temperature. May be.
In the case where the adhesive force of the transfer surface of the intermediate has a temperature dependency, the transfer from the intaglio to the intermediate and the retransfer from the intermediate to the substrate can be easily performed by controlling the temperature.
[0011]
As described in claim 3, the transfer surface of the intermediate has a property that the adhesive strength is reduced by the irradiation of ultraviolet rays, and the intermediate may be irradiated with ultraviolet rays in the fourth step.
When the conductive paste is an ultraviolet curable type, the hardness of the conductive paste is further increased by irradiating ultraviolet rays for reducing the adhesive strength of the intermediate. Therefore, the transferability from the intermediate to the substrate is further improved.
When the conductive paste is of a thermosetting type, the hardness of the conductive paste is not affected by the irradiation of ultraviolet rays for reducing the adhesive strength of the intermediate.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a first embodiment of a transfer apparatus for carrying out the method of the present invention.
This transfer device includes a cylindrical drum-shaped intaglio 1. The intaglio 1 is formed of a material having a UV transmittance, such as transparent glass, and has a pattern groove 2 formed on an outer surface thereof corresponding to a desired thick film wiring pattern. The depth of the pattern groove 2 is preferably, for example, 20 μm or more, and the aspect ratio (length / width) is close to 1. The diameter of the intaglio 1 is desirably 300 to 600 mm. The intaglio 1 is driven at a constant speed in the direction of the arrow.
[0013]
A supply device 3 for supplying the conductive paste P to the pattern grooves 2 is provided on the outer peripheral portion of the intaglio 1. The conductive paste P contains a metal powder or the like, and causes a curing reaction when irradiated with ultraviolet rays. The conductive paste P may be of a solvent type as long as it has high drying properties. However, a non-solvent type is preferable because a volume reduction during drying can be prevented. The supply device 3 includes a paste receiver 4 for storing the conductive paste P, an application roll 5 for applying the paste P of the paste receiver 4 to the intaglio 1, and a squeegee 6 for scraping the paste P other than the grooves. The squeegee 6 is preferably made of a hard resin such as polyacetal. The conductive paste P is completely filled in the pattern groove 2 by the squeegee 6.
[0014]
The conductive paste P filled in the pattern groove 2 causes a curing reaction to occur in the conductive paste P by passing through the exposure unit 10 and hardens the entire surface of the conductive paste P to a predetermined hardness. This hardness is for obtaining a cohesive force and a peeling force enough to withstand the transfer of the conductive paste P from the intaglio 1 to the intermediate 24 described later. The exposure unit 10 is provided with a light source 11 for irradiating ultraviolet UV from inside the intaglio 1 and a light source 12 for irradiating ultraviolet UV from outside the intaglio 1. In addition, 13 and 14 are filters that transmit only ultraviolet rays. As the light sources 11 and 12, a high-pressure mercury lamp, a metal halide lamp, or the like is used, and ultraviolet rays are irradiated so that the respective exposure amounts are, for example, about 0.2 to 1.0 J / cm ² . At this time, it is desirable that the ultraviolet intensity is 0.1 to 0.2 W / cm ² , the irradiation time is 1 to 10 seconds, and the rotational speed of the intaglio 1 is about 2 rpm.
By irradiating ultraviolet rays UV from both the front and back sides of the intaglio 1, the exposed portions of the conductive paste P exposed on the surface of the intaglio 1 are directly irradiated with ultraviolet rays, and the conductive paste P in contact with the grooves 2 of the intaglio 1 The portion is irradiated with ultraviolet light through the intaglio 1. As a result, the entire surface of the conductive paste P is cured (dried) to a predetermined hardness.
[0015]
The conductive paste P cured to a predetermined hardness is transferred to the outer peripheral surface of the carrier tape 24 circling in the direction of the arrow between the three rolls 21, 22, 23 in the transfer section 20. The roll 21 is a pressing roll that presses the carrier tape 24 against the intaglio 1, the roll 22 is a transfer roll that presses the carrier tape 24 to a transfer roll 32 described below, and the roll 23 is a guide roll. The carrier tape 24 serves as an intermediate for receiving the conductive paste P from the intaglio 1 and delivering it to the substrate 30. In this embodiment, the tape has an adhesive surface on the outer peripheral surface, and the adhesive force changes with temperature. You are using Specifically, an Intellimer tape (trade name) manufactured by Nitta Corporation, a cool-off type CS5025LC or a warm-off type WS5030LC can be used. The former tape exhibits adhesive strength at 50 ° C. or higher, and loses adhesive strength at 50 ° C. or lower. Therefore, a heating plate 25 for heating the carrier tape 24 to, for example, about 60 ° C. is provided between the guide roll 23 and the pressing roll 21, and the carrier tape 24 is cooled to around room temperature between the pressing roll 21 and the transfer roll 22. A cooling plate 26 is provided. By repeating heating and cooling of the carrier tape 24 in this manner, the carrier tape 24 is used repeatedly. The conductive paste P is reliably transferred from the intaglio 1 to the carrier tape 24 due to the difference in adhesive strength between the intaglio 1 and the carrier tape 24.
Instead of the heating plate 25, a heater may be provided inside the pressing roll 21, so that the carrier tape 24 is pressed against the intaglio 1 and simultaneously the adhesive force of the carrier tape 24 is generated. Instead of the cooling plate 26, a cooling means may be provided inside the transfer roll 22 so that the carrier tape 24 is pressed against the base 30 and the adhesive strength of the carrier tape 24 is reduced at the same time.
[0016]
The carrier tape 24 to which the conductive paste P has been transferred passes through the cooling board 26, so that its adhesive strength is reduced. The carrier tape 24 with the conductive paste P having reduced adhesive strength is sent to the retransfer unit 31. A transfer roll 32 paired with the transfer roll 22 is disposed in the retransfer unit 31, between which the base 30 and the carrier tape 24 are pressed against each other, and the conductive paste P is retransferred to the base 30. Here, a ceramic green sheet lined with a carrier film is used as the base 30, and is continuously supplied from a supply roll 33. In order to enhance the transferability of the conductive paste P from the carrier tape 24 to the base 30, a compressive load of about 200 to 500 kg / cm ² is preferably applied. When the conductive paste P is filled into the pattern groove 2 by the squeegee 6, even if there is a scraping residue (ground stain) on the surface of the intaglio 1, the ground stain is transferred to the carrier tape 24 because the film thickness is very thin. However, it is not transferred to the substrate 30. Therefore, a beautiful conductor pattern free from background contamination can be obtained on the surface of the base 30. In addition, by using rubber rolls having relatively high hardness (for example, JIS-A60 or more) as the transfer rolls 22 and 32, transfer without background contamination can be realized more effectively.
When a warm-off type is used as the carrier tape 24, a heater or the like may be provided inside the transfer rolls 22 and 32 to heat the carrier tape 24 and the base 30 to, for example, 60 to 90 ° C. In this case, at the same time as the adhesive strength of the carrier tape 24 is reduced, the binder component inside the base 30 is softened, so that there is an advantage that the transferability of the conductive paste P is further improved.
[0017]
The carrier tape 24 after the transfer is sent from the transfer roll 22 to the transfer unit 20 again via the guide roll 23. On the other hand, the base 30 to which the conductive paste P has been transferred is collected by the take-up roll 34. Thereafter, the base body 30 to which the conductive paste P has been transferred is peeled off from the carrier film and laminated in a predetermined number, then cut into a predetermined size, sent to a firing furnace and fired simultaneously with the conductive paste P. Here, the metal powder contained in the conductive paste P is melted to form a thick film wiring, and the base 30 is changed to a ceramic multilayer chip component.
In the above embodiment, since the carrier tape 24 is used repeatedly, the carrier tape 24 is placed in the middle of the circulation route of the carrier tape 24 (between the transfer roll 22 and the guide roll 23 or between the guide roll 23 and the pressing roll 21). Cleaning means may be provided for removing background contamination of the conductive paste P attached to the surface.
[0018]
FIG. 2 shows a second embodiment of the transfer apparatus for carrying out the method of the present invention.
In this embodiment, as an intermediate, a carrier tape 40 whose adhesive strength is reduced by ultraviolet irradiation is used. The same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description will be omitted.
The adhesive surface of the carrier tape 40 continuously supplied from the supply roll 41 is pressed against the intaglio 1 by the pressing roll 21. The conductive paste P filled into the pattern grooves 2 of the intaglio 1 and hardened to a predetermined hardness is reliably transferred from the intaglio 1 to the carrier tape 40 due to the difference in adhesive strength between the intaglio 1 and the carrier tape 40. The carrier tape 40 is irradiated with ultraviolet rays UV by the UV light source 41 disposed between the pressing roll 21 and the transfer roll 22 and on the back side of the carrier tape 40, and the adhesive strength is reduced. As such a carrier tape 40, a UV release tape, for example, VD-15 manufactured by Nitto Denko Corporation can be used. The amount of ultraviolet light is preferably, for example, 0.4 J / cm ² or more (wavelength: 365 nm).
The carrier tape 40 with the conductive paste P having reduced adhesive strength is pressed against the base 30 at the retransfer unit 31, and the conductive paste P is retransferred to the base 30. The carrier tape 40 after the retransfer is collected by the take-up roll 43 via the transfer roll 22.
In this embodiment, not only the conductive paste P but also the intermediate (carrier tape) 40 is treated with ultraviolet light, so that the paste can be hardened (dried) and the adhesive strength can be reduced quickly and reliably. In addition, since the carrier tape 40 is not affected by heat, the tape 40 does not expand and contract, so that a pattern shift can be prevented.
[0019]
FIG. 3 shows a third embodiment of the transfer apparatus for carrying out the method of the present invention.
In this embodiment, a flat intaglio 50 is used, a thermosetting type is used as the conductive paste P, and a heating plate 51 is used to cure the conductive paste P. The same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description will be omitted.
The intaglio 50 is made of a hard flat plate such as transparent glass, and has a pattern groove 2 formed on the surface. The pattern groove 2 preferably has a depth of 20 μm or more and an aspect ratio (length / width) of 1. In the first step, the conductive paste P is supplied onto the intaglio 50, and the excess conductive paste P is scraped off with the squeegee 6, so that the pattern groove 2 is filled with the conductive paste P.
[0020]
The intaglio 50 filled with the conductive paste P is conveyed onto the heating platen 51 in the second step, and the conductive paste P is cured or dried to a predetermined hardness. The intaglio 50 is transported to the third step while maintaining the conduction heat from the heating plate 51, where it is overlapped with the carrier tape 24 as an intermediate at the position of the first roll 52. As in the first embodiment, the carrier tape 24 is a pressure-sensitive adhesive sheet having a temperature dependency. Specifically, the carrier tape 24 has an adhesive property at a high temperature (for example, 50 ° C. or more) and a low temperature (50 ° C. or less). It is preferable to use a sheet having a property of losing tackiness. Therefore, when the carrier tape 24 is brought into contact with the intaglio 50, the heat generates an adhesive force. The carrier tape 24 circulates between the first roll 52 and the second roll 53 in the direction of the arrow, and when the carrier tape 24 separates from the intaglio 50 at the position of the second roll 53, the carrier tape 24 uses the adhesive force of the carrier tape 24. The conductive paste P hardened to a predetermined hardness in the groove 2 of the intaglio 50 is transferred to the carrier tape 24.
The carrier tape 24 to which the conductive paste P has been transferred by the second roll 53 is cooled by a cooling means 54 such as a blower while moving around the second roll 53, and the adhesive strength is reduced. The carrier tape 24 with the conductive paste P having reduced adhesive strength is sent to the retransfer unit 31, and the base 30 and the carrier tape 24 are pressed against each other between the second roll 53 and the transfer roll 32. It is retransferred to the substrate 30.
[0021]
In the third embodiment, a heating plate 51 such as a hot plate is used as a means for curing or drying the conductive paste P to a predetermined hardness, but the intaglio 50 is put into a heating atmosphere such as an oven to cure the conductive paste P. Alternatively, it may be dried.
In the third embodiment, the adhesive force of the carrier tape 24 is generated by the retained heat of the intaglio 50 given from the heating plate 51, but separately from the second step, the adhesive force of the carrier tape 24 is also generated in the third step. A heating means for generating a force may be provided.
The cooling means 54 for reducing the adhesive strength of the carrier tape 24 is not limited to a blower, and other means may be used.
The retransfer unit 31 is not limited to the one provided around the second roll 53, and may be provided around the first roll 52.
[0022]
FIG. 4 shows a fourth embodiment of the transfer apparatus for carrying out the method of the present invention.
In this embodiment, a plate-shaped intaglio 50 similar to that of the third embodiment is used, and an ultraviolet curing type is used as the conductive paste P. In order to cure the conductive paste P, ultraviolet rays UV are applied from above and below the intaglio 50. An exposure unit 10 including light sources 11 and 12 for irradiation and filters 13 and 14 is provided.
The intaglio 50 in which the conductive paste P has been hardened or dried to a predetermined hardness is conveyed to the third step, where it is overlapped with the carrier tape 24 as an intermediate at the position of the first roll 52. As in the first embodiment, the carrier tape 24 is a pressure-sensitive adhesive sheet having a temperature dependency. Here, the carrier tape has an adhesive property at a high temperature (for example, 50 ° C. or higher) and has an adhesive property at a low temperature (50 ° C. or lower). Use a sheet that loses its properties. The first roll 52 is provided with a heater 52a inside. When the carrier tape 24 is pressed against the intaglio 50 by the first roll 52, the heat generates an adhesive force on the carrier tape 24. The carrier tape 24 circulates between the first roll 52 and the second roll 53 in the direction of the arrow, and when the carrier tape 24 separates from the intaglio 50 at the position of the second roll 53, the carrier tape 24 uses the adhesive force of the carrier tape 24. The conductive paste P hardened to a predetermined hardness in the groove 2 of the intaglio 50 is transferred to the carrier tape 24.
The carrier tape 24 to which the conductive paste P has been transferred by the second roll 53 is cooled by the cooling means 54 while moving around the second roll 53 as in the third embodiment, and the adhesive strength is reduced. The carrier tape 24 with the conductive paste P having reduced adhesive strength is sent to the retransfer unit 31, and the base 30 and the carrier tape 24 are pressed against each other between the second roll 53 and the transfer roll 32. It is retransferred to the substrate 30.
[0023]
In the fourth embodiment, the adhesive force of the carrier tape 24 is generated by the heater 52 a provided inside the first roll 52, but the adhesive force of the carrier tape 24 is generated separately from the first roll 52. Heating means may be provided.
The cooling means 54 for reducing the adhesive strength of the carrier tape 24 is not limited to a blower, and other means may be used.
[0024]
In the first to fourth embodiments, the intaglios 1 and 50 are formed of a hard material such as transparent glass. However, as shown in FIG. 5, the pattern grooves 2 are formed on the surface of a transparent resin film such as PET or PC by laser processing. May be used, and these intaglios 1 and 50 may be bonded to the outer surfaces of transparent supports 60 and 61 made of a hard material such as transparent glass.
FIG. 5A shows a drum-shaped intaglio 1, and FIG. 5B shows a plate-shaped intaglio 50.
Also in this case, since both the intaglio and the support have ultraviolet transmittance, the entire surface of the conductive paste P filled in the pattern grooves can be cured by irradiating ultraviolet rays from inside the support and from outside the intaglio. . In addition, since the intaglio is formed by laser processing a flexible resin film, the processing is easy. Further, since the intaglio is prevented from being deformed by the support, when the conductive paste P is transferred from the intaglio to the carrier tape or when the conductive paste P is transferred from the intaglio to the substrate, the intaglio is not deformed, and the pattern distortion is prevented. And intaglio printing can be prevented from deteriorating.
[0025]
The present invention is not limited to the above embodiments, and new embodiments can be configured by appropriately combining the first to fourth embodiments.
For example, in a transfer device using a flat intaglio as shown in FIGS. 3 and 4, a sheet whose adhesive force is reduced by ultraviolet rays shown in FIG. 2 may be used as a carrier tape.
Although the ultraviolet curing type has been described as an example of the radiation-curable conductive paste P, a conductive paste having a property of being cured by visible light may be used.
Although the heating panels 25 and 51 are used as the heating means, a hot wire heater such as an infrared heater may be used.
When the intaglio 1 has a flat plate shape as in the third embodiment, the intaglio 1 can be formed only of a transparent resin material such as a PET film.
Further, as a method of improving the transferability of the conductive paste from the intaglio to the intermediate (carrier tape), the surface of the intaglio may be previously coated with a release agent such as a fluororesin. Further, in order to improve retransferability from the intermediate to the substrate, a pressure-sensitive adhesive or an adhesive may be previously applied to the surface of the substrate.
[0026]
【The invention's effect】
As is apparent from the above description, according to the invention of claim 1, when the conductive paste is transferred from the intaglio to the intermediate and then re-transferred to the substrate, the adhesive in the intaglio is utilized by utilizing the adhesiveness of the intermediate. Can be reliably transferred to the intermediate body, and transfer failure can be resolved even with a thick-film conductive paste. When retransferring from the intermediate to the substrate, the conductive paste can be reliably retransferred to the substrate because the adhesiveness of the intermediate is reduced.
By changing the adhesiveness of the intermediate as described above, the conductive paste in the intaglio can be reliably transferred to the substrate via the intermediate, and the background stain is not transferred to the substrate. The stress applied to the conductive paste and the base is small, and the wiring pattern and the base are less damaged. As a result, it is possible to form a thick film wiring having a beautiful pattern shape with no background contamination on the base.
[Brief description of the drawings]
FIG. 1 is a structural diagram of a first embodiment of a transfer device used in the method of the present invention.
FIG. 2 is a structural view of a second embodiment of the transfer device used in the method of the present invention.
FIG. 3 is a structural view of a third embodiment of a transfer device used in the method of the present invention.
FIG. 4 is a structural view of a fourth embodiment of a transfer device used in the method of the present invention.
FIG. 5 is a side view of another example of the intaglio.
[Explanation of symbols]
P Conductive paste 1 Intaglio 2 Pattern groove 6 Squeegee 8 Intermediate (carrier tape)
10 Exposure unit 20 Transfer unit 30 Base (ceramic green sheet)
31 Retransfer unit

Claims (3)

A method for forming a thick film wiring on a substrate, comprising:
A first step of embedding a conductive paste in an intaglio pattern groove in which a pattern groove corresponding to a desired thick film wiring pattern is formed on the surface;
A second step of drying or curing the conductive paste embedded in the pattern groove to a hardness that can be peeled from the intaglio,
A third step of transferring the conductive paste dried or hardened to the peelable hardness from the intaglio to the transfer surface of the intermediate having adhesiveness,
A fourth step of reducing the adhesiveness of the transfer surface of the intermediate,
And a fifth step of retransferring the conductive paste transferred to the intermediate to a substrate. The transfer surface of the intermediate has a property that the adhesive force changes depending on the temperature, and the third step is performed at a high adhesive force temperature, and the fourth step is performed at a low adhesive force temperature. The method for forming a thick film wiring according to claim 1. 2. The method according to claim 1, wherein the transfer surface of the intermediate has a property that the adhesive strength is reduced by the irradiation of ultraviolet rays, and the intermediate is irradiated with ultraviolet rays in the fourth step. Method.

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