JP2007227956A - Method for forming electronic circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain space savings with regard to a method for forming an electronic circuit, while assuring high flexibility. <P>SOLUTION: In the method for forming the electronic circuit in which, on a printed-wiring board 26, only a board 26 is removed from an electronic module in which an electronic component 22 is mounted, and the electronic module which consists of the electronic component 22 and wiring 24 is deformed to be sealed and fixed without the board 26, after adhering the wiring 24 on the board 26 with a tape 200 which loses adhesion properties with heat, the removal of the board 26 from the electronic module is attained by a heat treatment at the time of mounting the electronic component 22. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for forming an electronic circuit, and more particularly, to a method for forming an electronic circuit as an electronic module including electronic components and wiring.

Conventionally, an electronic circuit in which an electronic component is mounted on a flexible printed wiring board is known (for example, see Patent Document 1). This electronic circuit is formed by mounting an electronic component on a substrate attached to and supported by a reinforcing plate, and then removing the reinforcing plate. In such a configuration, since the substrate is supported by the reinforcing plate, the handling of the flexible substrate can be facilitated in the mounting process of the electronic component and the transporting process before and after the electronic component. This makes it possible to stabilize the mounting of the electronic component on the substrate.
Japanese Patent Laid-Open No. 2001-210998

  However, in recent years, the number of components (elements) mounted on an electronic circuit has increased with the improvement in performance of electronic devices, and there has been a situation in which the area occupied by the electronic circuit increases. Even in such a situation, space saving is required at the installation location of the electronic device. However, in the above-described conventional electronic circuit, there is a substrate on which an electronic component is mounted, so that the substrate is flexible. Even if a flexible substrate is used, there is a limit in reducing the size and space of electronic circuits.

  The present invention has been made in view of the above-described points, and an object of the present invention is to provide a method for forming an electronic circuit capable of ensuring high flexibility and saving space.

  The purpose of the electronic circuit is to remove only the substrate from the electronic module on which the electronic component is mounted on the printed wiring board, and to deform and seal and fix the electronic module composed of the electronic component and the wiring in the absence of the substrate. A method of forming an electronic circuit in which a substrate and a wiring are pasted with a tape that loses adhesive strength due to heat, and then the substrate is removed from the electronic module by heat treatment when mounting the electronic component. Is achieved.

  In the invention of this aspect, the wiring is affixed to the substrate with a tape that loses the adhesive force due to heat. And when heat processing are performed at the time of mounting of an electronic component, the board | substrate is removed from an electronic module because the adhesive force of a tape is lost with the heat. When the substrate is removed from the electronic module, the electronic module becomes only a circuit composed of electronic components and wirings connecting the electronic components, and space saving for the substrate is achieved. In the present invention, the electronic module from which the substrate has been removed is freely deformed and sealed and fixed. In this case, since the electronic module can be deformed without being restrained by the substrate, high flexibility is ensured.

  In the electronic circuit forming method described above, after the substrate is removed from the electronic module in which the substrate is present by the heat treatment, before the electronic module including the electronic component and the wiring without the substrate is deformed, the substrate is The removed electronic module is coated with an adhesive and wrapped in a heat-shrinkable film, and the heat-shrinkable film is shrunk by applying heat while curing the adhesive, and then the heat-shrinkable film is peeled off to bond the adhesive. If the agent is completely cured, the wiring shrinks due to the heat shrinkage of the heat shrinkable film after the substrate is removed from the electronic module by the heat treatment, so that it is possible to reliably prevent a short circuit from occurring in the wiring.

  Further, in the electronic circuit forming method described above, after the substrate is removed from the electronic module in which the substrate is present by the heat treatment, before the electronic module including the electronic component and the wiring without the substrate is deformed, the substrate is If the masking sol is applied to the removed electronic module and then cured, the unnecessary portion of the masking sol is cut off. After the substrate is removed from the electronic module by heat treatment, the electronic module Since it is coded by the masking sol and unnecessary portions thereof are cut, the electronic module can be reduced in size and can be easily handled.

  According to the present invention, it is possible to ensure high flexibility of an electronic circuit by realizing deformation of the electronic module without being constrained by the substrate, and to save space of the electronic circuit by removing the substrate. Can do.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

  1 and 2 are views for explaining a method of forming an electronic circuit 20 according to the first embodiment of the present invention. 1 is a top view of the electronic circuit 20, and FIG. 2 is a side view of the electronic circuit 20. 1 and 2, the method of forming the electronic circuit 20 is shown in time series in the order of (A), (B),.

  In the present embodiment, the electronic circuit 20 includes a plurality of electronic components 22 that are elements such as capacitors, resistors, and ICs, and wirings 24 as conductors that connect the electronic components. The electronic circuit 20 finally has a configuration that does not include a substrate itself on which the electronic component 22 is mounted, and is configured only by the electronic component 22 and the wiring 24. Hereinafter, a method for forming the electronic circuit 20 having no substrate will be described.

  First, the wiring 24 is formed by printing a conductive circuit pattern on the substrate 26 with copper foil or the like. The substrate 26 is made of a water-soluble material such as modified polyvinyl alcohol (for example, Nippon Synthetic Chemical Industry Co., Ltd., trade name: Ecomaty AX) or water-soluble paper (for example, Mishima Paper Co., Ltd., trade name: MDP). And has the property of being soluble in water. At a desired position on the substrate (printed wiring substrate) 26 on which the wiring 24 is formed, for example, a paste containing a solder grain or an adhesive is applied through a mask, and a plurality of electronic components 22 are placed. These electronic components 22 are mounted and fixed on the printed wiring board 26 by being heat-treated in a mounted state. In mounting the electronic component 22, when the strength of the water-soluble substrate 26 is insufficient, the substrate 26 is mounted within the range in which the mounting of the electronic component 22 on the substrate 26 and the solder reflow are not hindered. It is good also as carrying out in the state arrange | positioned on the resin board 28 grade | etc., As shown in FIG.

  When the electronic module having the electronic component 22 mounted on the substrate 26 is configured, the resin plate 28 is then removed as necessary, and the electronic module is immersed in water. Since the board | substrate 26 is a water-soluble member, when the board | substrate 26 is immersed in water, the board | substrate 26 will melt | dissolve in water and the board | substrate 26 will be removed from the electronic module in which the electronic component was mounted. When the substrate 26 is dissolved in water, the electronic component 22 and the wiring 24 made of copper foil may not be held by the substrate 26. Therefore, as will be described in detail later, An insulating material is applied to the electronic module including the component 22 and the wiring 24, and the electronic component 22 and the wiring 24 are coated with an insulating film.

  The insulating material applied to the electronic module described above is a deformable and flexible synthetic resin solution such as a methacrylic / acrylic copolymer resin (for example, Rohm & Haas, trade name; Paraloid B72). Or an ultraviolet curable resin such as urethane acrylate (for example, Three Bond, trade name: 3061H). Further, since the wiring 24 is made of copper foil as described above, it is easily formed. For this reason, when the electronic component 22 and the wiring 24 of the electronic module not having the substrate 26 are coated with an insulating material, the deformation (shape change) of the electronic module can be performed without causing the wiring 24 to be cut. The relative positions of the electronic component 22 and the wiring 24 can be changed.

  Then, after the electronic module on which the insulating coating has been performed is changed in shape according to the shape of the place where the electronic circuit 20 is to be installed or after the shape is shrunk, the epoxy adhesive is cured in that state. The shape is fixed. According to this configuration, by removing the substrate 26, the electronic circuit 20 configured only by the plurality of insulating-coated electronic components 22 and the wiring 24 connecting them is installed in a flexible manner corresponding to the installation location. In addition, it is possible to save the space of the electronic circuit 20 itself.

  By the way, there may occur a situation in which the shape of the electronic component 22 and the wiring 24 made of copper foil is not fixed until the electronic module is deformed and cured after the substrate 26 is removed from the electronic module. Handling such as a short circuit may be difficult. Therefore, in this embodiment, when the substrate 26 is removed from the electronic module or after that, the electronic module is easily handled by applying an insulating material or making the electronic module compact.

  Hereinafter, in the present embodiment, first to sixth methods for facilitating handling of an electronic module including the electronic component 22 and the wiring 24 from which the substrate 26 has been removed will be described with reference to FIGS. 3 to 8. To do. In FIG. 3 to FIG. 8, the method order is shown in time series in the order of (A), (B),.

[First method]
FIG. 3 is a diagram for explaining a first technique for facilitating the handling of the electronic module. In the first method, when the electronic module is immersed in water for dissolving and removing the substrate 26, a water-soluble polymer as an insulating material is applied to the water. As this water-soluble polymer, CMC (carboxymethylcellulose) having a high viscosity or the like is used (for example, Daicel Chemical Industries, Ltd., trade name: CMC Daicel). In such a configuration, when the substrate 26 is dissolved in water, the water-soluble polymer is dissolved and spreads at the same time, and the electronic component 22 and the wiring 24 of the electronic module are coated by the viscosity. Then, after such coating is applied, the shape of the electronic module is changed, and the shape is fixed by curing the adhesive or the like.

  In addition, in the structure which only coats an electronic module with the viscosity of water-soluble polymer, intensity | strength is still insufficient and the handling may become difficult. Therefore, as shown in FIG. 3B, a metal foil 30 such as aluminum that can be easily deformed and can maintain its shape may be attached to the electronic module coated as described above. When such a process is performed, the foil 30 is attached by the viscosity of the water-soluble polymer that coats the electronic module. Then, after the foil 30 is attached to the electronic module, the shape of the electronic module is changed integrally with the foil 30, and the portion where the foil 30 is not attached is first cured with an adhesive or the like, and then the foil is attached. It peels off and the part which foil 30 was affixed is hardened (FIG.3 (C)). In addition, it is good also as functioning as the electronic circuit 20 with the foil 30 affixed on an electronic module from viewpoints, such as shielding property, heat dissipation, and intensity | strength.

  According to this method, the substrate 26 is dissolved and removed from the electronic module at the same time, and at the same time, the electronic module is coated with the water-soluble polymer or the foil 30. The electronic module can be easily handled immediately after that.

[Second method]
FIG. 4 is a diagram for explaining a second method for facilitating the handling of the electronic module. In this second method, before the substrate 26 is dissolved and removed from the electronic module, the electronic module integrated with the substrate 26 is set on the block 40 as shown in FIG. In this block 40, a gap 42 is formed at a position directly below the electronic component 22 and the wiring 24 of the electronic module by a groove or a hole that matches the shape of the electronic component 22 and the wiring 24. Therefore, when the electronic module is set on the block 40 as described above, the electronic component 22 and the wiring 24 face the gap 42 of the block 40 through the substrate 26. In addition, the block 40 may be integrally formed, and may be divided | segmented into plurality so that removal is possible.

  In such a structure, when the electronic module is immersed in water and the substrate 26 is dissolved and removed, the electronic component 22 and the wiring 24 fall because they are not supported by the substrate 26. Since the electronic component 22 and the wiring 24 are initially opposed to the gap 42 of the block 40 through the substrate 26 as described above, if the electronic component 22 and the wiring 24 are dropped due to the cancellation of the support by the substrate 26, the block as shown in FIG. It fits into 40 gaps 42. In such a state, as shown in FIG. 4C, silicone or the like as a flexible insulating material is poured into the gap 42 and cured. When the curing of the silicone is completed, the entire block 40 is removed, and the shape of the electronic module cured by the silicone is deformed and cured with an adhesive or the like (FIG. 4D).

  According to this method, after the substrate 26 is dissolved and removed from the electronic module, the electronic component 22 and the wiring 24 fitted in the mold are coated with silicone. It is possible to reliably prevent the wirings 24 from being short-circuited, and the electronic module can be easily handled immediately after that.

[Third method]
FIG. 5 is a diagram for explaining a third method for facilitating the handling of the electronic module. In the third method, the wiring 24 embedded in the water-soluble substrate 26 has a spring-like or accordion-like elastic structure that can be expanded and contracted. Then, the wiring 24 is embedded in the substrate 26 while being pulled from the normal state, and is maintained in the pulled state while the substrate 26 is present (FIG. 5A). In this state, the electronic component 22 is mounted on the substrate 26 and fixed. If the board | substrate 26 melt | dissolves in water from such a state, the wiring force will shrink | contract as shown in FIG. After the wiring 26 is completely shrunk, an adhesive or the like is sprayed on the electronic module and cured (FIG. 5C).

  According to this method, since the wiring 24 contracts due to the spring action after the substrate 26 is dissolved and removed from the electronic module, unlike the case where the contraction does not occur, it is ensured that the wiring 24 is loosened or short-circuited. The electronic module can be easily handled even if the substrate 26 is removed.

[Fourth Method]
FIG. 6 is a diagram for explaining a fourth method for facilitating the handling of the electronic module. In the fourth method, after the electronic component 22 is mounted on the printed wiring board 26, the dry gel 50 is applied to the electronic module before the substrate 26 is dissolved and removed from the electronic module with water. This dry gel 50 has the property of swelling when water is present in the surroundings and contracting when water is exhausted. Then, after the dry gel 50 is applied to the electronic module, the electronic module is immersed in water to dissolve the substrate 26.

  In such a configuration, when the substrate 26 is dissolved in water, the dried gel 50 swells simultaneously as shown in FIG. 6A, and the electronic component 22 and the wiring 24 of the electronic module are coated by the viscosity. After the electronic module is coated in this manner, the swollen gel 50 is dried to be dehydrated and contracted. At this time, the wiring 24 connecting the electronic components 22 contracts as the gel 50 contracts. After the wiring 24 is shrunk, an adhesive or the like is sprayed on the electronic module and cured (FIG. 6B).

  According to such a method, since the substrate 26 is dissolved and removed from the electronic module at the same time, the electronic module is coated by the swelling of the dry gel 50, and then the wiring 24 is contracted by the contraction of the gel 50. It is possible to reliably prevent the wiring 24 from being loosened or short-circuited, and the electronic module can be easily handled even if the substrate 26 is removed.

[Fifth Method]
FIG. 7 is a diagram for explaining a fifth method for facilitating handling of the electronic module. In this fifth method, after removing the substrate 26 from the electronic module, an adhesive 60 is applied to the electronic module, and the electronic module is cured in a state of being wrapped with a heat shrink film 62 (FIG. 7A). )). The heat shrink film 62 is made of polyethylene or the like (for example, Sekisui Film Co., Ltd., trade name: Polish LB). Then, before the adhesive 60 is completely cured, the heat shrink film 62 is shrunk by applying heat. At this time, the wiring 24 connecting the electronic components 22 contracts as the heat shrink film 62 contracts (FIG. 7B). After the wiring 24 is shrunk, the heat shrink film 62 is peeled off, and the adhesive 60 is completely cured to fix the shape of the electronic module. If the heat shrink film 62 is shrunk in a state where the adhesive 60 is not dry, there is a possibility that a short circuit between the wirings 24 may occur. Therefore, in order to avoid such a situation, the adhesive 60 is somewhat dry. It is appropriate to carry out in a semi-dry state.

  According to this method, after the substrate 26 is dissolved and removed from the electronic module, the wiring 24 contracts due to the thermal contraction of the heat shrink film 62 covering the electronic module to which the adhesive 60 is applied. It is possible to reliably prevent the occurrence of slack and short circuit, and the electronic module can be easily handled even if the substrate 26 is removed.

[Sixth Method]
FIG. 8 is a diagram for explaining a sixth technique for facilitating the handling of the electronic module. In the sixth method, after removing the substrate 26 from the electronic module, a masking sol 70 as an insulator is applied to the electronic module (FIG. 8A). This masking sol has low viscosity, high fluidity, and liquid properties (for example, GSI Creos, Inc., trade name: Mr. Masking Sol). When the masking sol 70 is cured, an unnecessary portion of the sol 70, that is, a space where the electronic component 22 and the wiring 24 are not present, is cut as shown in FIG. In accordance with the shape of the place where the electronic circuit 20 is installed, the size of the electronic circuit 20 is reduced and the shape is changed.

  According to such a method, after the substrate 26 is dissolved and removed from the electronic module, the electronic module is coated with the masking sol 70 and unnecessary portions thereof are cut, so that the electronic module is reduced in size. Can be handled easily.

[Seventh method]
FIG. 9 is a diagram for explaining a seventh technique for facilitating handling of the electronic module. In the seventh method, after the electronic component 22 is mounted on the printed wiring board 26, the mounting surface of the electronic module is mounted on the mounting surface of the electronic module with the insulating material 80 such as the synthetic resin solution or the ultraviolet curable resin. An insulating coating is applied (FIG. 9A). In this state, the electronic module is immersed in water to dissolve the substrate 26. Then, the insulating coating 80 is applied to the portion that has not been provided with the insulating coating due to the presence of the substrate 26 (FIG. 9B). After the insulation coding is applied to the entire electronic module in this way, the electronic module is deformed according to the shape of the place where the electronic circuit 20 is installed, and is cured and fixed with an adhesive or the like (FIG. 9 ( C)).

  According to such a method, the mounting surface is coated with the insulating material once the substrate 26 is set on the electronic module, and then the surface that faces the substrate 26 in a state where the substrate 26 is dissolved in water. Since it is coated with an insulating material, it is possible to reliably prevent the wirings 24 from being short-circuited thereafter, and the electronic module can be easily handled immediately after that.

  FIG. 10 is a diagram for explaining the places where the electronic circuit 20 of this embodiment can be installed. Moreover, FIG. 11 shows the figure for demonstrating the installation location of the electronic circuit in which a board | substrate exists contrasted with the electronic circuit 20 of a present Example. In the configuration in which the electronic components and wiring are fixed on the substrate 102 that is hard to some extent as in the comparative electronic circuit 100 shown in FIG. 11, since the substrate 102 exists, as shown in FIGS. It is difficult to install the contrasting electronic circuit 100 at a stepped portion, and as shown in FIG. 3C, the two-dimensional exclusive area must be increased to some extent when all electronic components are mounted. is required.

  On the other hand, in the electronic circuit 20 of this embodiment, the electronic component 22 and the wiring 24 are placed on the substrate 26 at the initial stage of manufacture, but finally the electronic component 22 without the substrate 26 is present. And the wiring 24, and can be freely deformed. For this reason, according to the present embodiment, as shown in FIG. 10, the electronic circuit 20 can be flexibly installed on a curved surface or a stepped portion without being constrained by the substrate 26 according to the shape of the portion. In addition, the electronic circuit 20 can be compactly embedded in a limited space without requiring a large area.

  In addition, in an electronic circuit without a substrate, there is a risk that heat dissipation, insulation, and shape stability of an electronic component or the like may be impaired. In this case, a heat dissipation gel (for example, around the electronic circuit 20) , Geltech Co., Ltd., trade name: DP100 and DP200), etc., and covering with a member with excellent heat dissipation, insulation, and shape stability to improve heat dissipation during operation of the electronic circuit, shape stability after installation It is also possible to improve the above-mentioned problems by improving the performance and insulation.

  In the first embodiment, a synthetic resin solution such as a methacrylic / acrylic copolymer resin, an ultraviolet curable resin such as urethane acrylate, a water-soluble polymer such as CMC, and a dry gel 50 are within the scope of the claims. The foil 30 corresponds to the “metal foil” described in the claims.

  By the way, in the said 1st Example, although the board | substrate 26 is comprised with a water-soluble material and it is supposed that the electronic circuit 20 without a board | substrate will be formed by melt | dissolving the board | substrate 26 in water, this invention is based on this. For example, the substrate may be made of foamed polystyrene, and an electronic circuit without the substrate may be formed by applying a solvent such as thinner to the substrate.

  Next, a second embodiment of the present invention will be described with reference to FIG.

  In the first embodiment described above, the board 26 on which the electronic component 22 is mounted is made of a water-soluble material, and the board 26 is dissolved in water, whereby an electronic module comprising the electronic part 22 and the wiring 24 having no board is electronically The circuit 20 is formed. On the other hand, in this embodiment, the electronic component 20 without the substrate is formed by eliminating the adhesive force between the substrate 26 and the electronic component 22 without melting the substrate 26.

  FIG. 12 is a diagram for explaining the method of forming the electronic circuit of this embodiment. In FIG. 12, the same components as those shown in FIGS. 1 and 2 are given the same reference numerals, and the description thereof is omitted or simplified. That is, in this embodiment, the wiring 24 is attached to the general substrate 26 with the peelable adhesive tape 200. That is, the wiring 24 is provided on the substrate 26 via the peelable adhesive tape 200. The peelable adhesive tape 200 is a tape that normally has high adhesive strength, but loses adhesive strength when heated and peels off (for example, Nitto Denko Corporation, trade name: Riva Alpha). Then, the electronic component 22 is mounted at a desired position in a state where the wiring 24 is applied to the substrate 26, and a heat treatment by solder reflow is performed.

  In the above configuration, when the heat treatment is performed when the electronic component 22 is mounted, the peelable adhesive tape 200 loses the adhesive force due to the heat, and thus the adhesive force between the wiring 24 and the substrate 26 is lost. In this case, the wiring 24 on which the electronic component 22 is mounted and the substrate 26 can be separated from each other, and the wiring 24 can be removed from the substrate 26, that is, the substrate 26 can be removed from the electronic module. When the substrate 26 is removed from the electronic module in this way and the electronic module has only the configuration of the electronic component 22 and the wiring 24, for example, in order to facilitate the handling of the electronic module, for example, the fourth and fourth described above are used. The insulating material is applied by the fifth or sixth method. Then, after the electronic module is changed to a desired shape or contracted, the electronic module is sealed and fixed by curing an adhesive or the like in that state.

  Thus, in the configuration of the present embodiment, the substrate 26 is removed from the electronic module by separating the electronic component 22 side from the substrate 26 with the peelable adhesive tape, that is, the electronic circuit 20 without the substrate functions. As in the configuration of the first embodiment described above, the electronic circuit 20 including only the plurality of insulating-coated electronic components 22 and the wiring 24 connecting them can be flexibly installed at the installation location. The electronic circuit 20 itself can be saved in space. Therefore, also in this embodiment, it is possible to obtain the same effect as in the case of the first embodiment described above.

  By the way, in the said 2nd Example, although what peeled with heat is used as the peeling type adhesive tape 200 which attaches the wiring 24 to the board | substrate 26, it peels by irradiating an ultraviolet-ray (UV) etc. to others. A thing may be used. As a peeling type adhesive tape which peels by irradiation of an ultraviolet-ray, there exists a brand name; Selfa etc. of Sekisui Chemical Co., Ltd. In such a configuration, if the electronic component 22 is mounted on the substrate on which the wiring 24 is provided via the peelable adhesive tape and then the electronic module is irradiated with ultraviolet rays, the substrate 26 and the electronic component 22 side Therefore, the electronic circuit 20 having no substrate can be formed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a state view of an electronic circuit for explaining an electronic circuit forming method according to a first embodiment of the present invention. It is a side view of the electronic circuit for demonstrating the formation method of the electronic circuit of a present Example. It is a figure for demonstrating the 1st method which makes handling of an electronic module easy. It is a figure for demonstrating the 2nd method which makes handling of an electronic module easy. It is a figure for demonstrating the 3rd method which makes handling of an electronic module easy. It is a figure for demonstrating the 4th method which makes handling of an electronic module easy. It is a figure for demonstrating the 5th method which makes handling of an electronic module easy. It is a figure for demonstrating the 6th method which makes handling of an electronic module easy. It is a figure for demonstrating the 7th method which makes handling of an electronic module easy. It is a figure for demonstrating the location which can install the electronic circuit in which the board | substrate of a present Example does not exist. It is a figure for demonstrating the installable location of the electronic circuit in which a board | substrate exists. It is a figure for demonstrating the formation method of the electronic circuit which is 2nd Example of this invention.

Explanation of symbols

20 Electronic Circuit 22 Electronic Component 24 Wiring 26 Substrate 200 Peelable Adhesive Tape

Claims (3)

A method of forming an electronic circuit in which only a substrate is removed from an electronic module on which an electronic component is mounted on a printed wiring board, and the electronic module composed of the electronic component and the wiring is deformed and sealed and fixed without the substrate ,
A method of forming an electronic circuit, wherein the substrate and the wiring are pasted together with a tape that loses adhesive strength by heat, and the removal of the substrate from the electronic module is realized by a heat treatment during mounting of the electronic component.   After the substrate is removed from the electronic module in which the substrate is present by the heat treatment, before the electronic module including the electronic component and the wiring in which the substrate is not present is deformed, the adhesive is applied to the electronic module from which the substrate has been removed. The heat shrink film is shrunk by applying heat while the adhesive is cured in a state of being wrapped in a heat shrink film, and then the heat shrink film is peeled off to completely cure the adhesive. The method for forming an electronic circuit according to claim 1.   After removing the substrate from the electronic module in which the substrate is present by the heat treatment, before deforming the electronic module including the electronic component and the wiring in which the substrate is not present, a masking sol is applied to the electronic module from which the substrate has been removed. The method for forming an electronic circuit according to claim 1, wherein the unnecessary part of the masking sol is cut after curing the mixing sol.

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