JPH11145603A - Thermosetting adhesive for temporary fixing of electronic components and method of fixing electronic components using the same - Google Patents

Abstract

(57) [Abstract] (Modified) [Problem] Despite curing at a temperature lower than the melting point of solder, it does not inhibit sinking of electronic components and self-alignment due to melting of solder, and a large resin mold Provided is a thermosetting adhesive for temporarily fixing electronic components, which provides sufficient adhesive strength even when components are soldered to a substrate and fixed with an adhesive. A thermosetting adhesive for temporarily fixing electronic components, wherein the curing time at 170 ° C. is 80 to 200 seconds, the curing time at 150 ° C. is 400 to 800 seconds, 60 ± 30 seconds. The temperature is raised from room temperature to 150 ± 20 ° C. and kept at 150 ± 20 ° C. for 70 ± 30 seconds.
Temperature rises from 150 ± 20 ° C to 230 ± 20 ° C in ± 10 seconds, and 230 ± 20 ° C to 170 ± 10 ° C in 40 ± 20 seconds
20% to 50% horizontal spread when cooled to
And the sag rate is 60 to 90%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thermosetting adhesive for temporarily fixing electronic parts and a method for bonding electronic parts.

[0002]

2. Description of the Related Art A conventional thermosetting adhesive for temporarily fixing electronic components (hereinafter, also referred to as an adhesive) has a small spread ratio upon heating and has a melting point (183 ° C.) of cream solder (hereinafter, also referred to as solder). However, the electronic component is already firmly fixed by the adhesive when the solder is melted, because it is hardened and solidified at a low temperature. Therefore, sinking and self-alignment of the electronic component due to the melting of the solder are hindered, and poor grounding of the electrodes of the electronic component (hereinafter, also simply referred to as grounding) and the printed circuit board of the electronic component (hereinafter, also simply referred to as substrate). Positional deviation was easy to occur. As a method for solving the above-mentioned problem, an adhesive for temporarily fixing an electronic component which cures at a temperature higher than the melting point of solder has been proposed (see Japanese Patent Application Laid-Open No. H8-130363).
This adhesive does not inhibit the sinking and self-alignment of the electronic component due to the melting of the solder, but since the curing temperature of the adhesive is high, for example, a large resin mold component S
When soldering OP (Small Outline Package), QFT (Quad Flat Package), or the like to a substrate and fixing the same with an adhesive, the temperature directly below the large resin mold component as described above is generally 20 degrees below the substrate surface temperature. Since the temperature was lower by ３０30 ° C., the adhesive applied to that portion was liable to be cured poorly, and the adhesive strength between the substrate and the electronic component by the adhesive became very weak. Those with weak adhesive force between such electronic components and the board,
When this is turned over and the electronic component is to be bonded to the back surface of the substrate in the same manner, the electronic component becomes SOP or Q.
In the case of FT or the like, problems such as dropping off from the substrate are likely to occur.

[0003]

SUMMARY OF THE INVENTION The present invention is directed to a thermosetting adhesive for temporarily fixing electronic components which cures at a temperature lower than the melting point of solder, but the sinking of electronic components due to the melting of solder. And self-alignment,
Thermosetting adhesive for temporarily fixing electronic components that provides sufficient adhesive strength even when a large resin mold component is soldered to a substrate and fixed with an adhesive, and an electronic component fixing method using the same Is to provide

[0004]

Means for Solving the Problems The present inventors have made intensive studies to solve the above problems, and as a result, have completed the present invention. That is, according to the present invention, the thermosetting electronic component temporary fixing method used in the electronic component fixing method for fixing the electronic component to the printed circuit board via the cream solder and the electronic component temporary fixing thermosetting adhesive. An adhesive, wherein (i) the curing time at 170 ° C. is 80 to 200 seconds, and (ii) the curing time at 150 ° C. is 400 to 8 seconds.
(Iii) It is heated from room temperature to 150 ± 20 ° C. in 60 ± 30 seconds, kept at 150 ± 20 ° C. for 70 ± 30 seconds, and 230 ± 150 ° C. in 30 ± 10 seconds. When the temperature is raised to ± 20 ° C and the horizontal spread rate is 20 to 50% and the sag rate is 60 to 90% when cooled from 230 ± 20 ° C to 170 ± 10 ° C in 40 ± 20 seconds, The present invention provides a thermosetting adhesive for temporarily fixing an electronic component. Further, according to the present invention, in the method for fixing an electronic component to a printed board, (i) applying cream solder and the thermosetting adhesive for temporarily fixing the electronic component to the printed board, And (iii) mounting the electronic component such that the electrode portion of the electronic component is located on the cream solder application portion and the non-electrode portion of the electronic component is located on the adhesive application portion.
The temperature of the cream solder and the adhesive applied on the substrate in the heating furnace is raised from room temperature to 150 ± 20 ° C. in 60 ± 30 seconds, kept at 150 ± 20 ° C. for 70 ± 30 seconds, and 150 ± 30 seconds in 30 ± 10 seconds. A step of raising the temperature from ± 20 ° C. to 230 ± 20 ° C. to melt the cream solder and gradually cure the adhesive;
Cooling from ± 20 ° C. to 170 ± 10 ° C. and solidifying.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The thermosetting adhesive for temporarily fixing electronic parts according to the present invention cures at a temperature lower than the melting temperature of solder of 183.degree. C., and the curing time at 170.degree.
To 200 seconds, preferably 120 to 180 seconds, and 1
The curing time at 50 ° C. is 400 to 800 seconds, preferably 500 to 700 seconds. If the curing time at 170 ° C. is faster than 80 seconds, and if the curing time at 150 ° C. is faster than 400 seconds, there is a problem that the spread of the adhesive becomes insufficient and the adhesive tends to be defective.
If the curing time at 70 ° C. is slower than 200 seconds,
If the curing time at 50 ° C. is longer than 800 seconds, the adhesive is not sufficiently cured, and particularly in the case of a large resin molded part, there is a problem that the adhesive easily falls off the substrate.

The adhesive for temporarily fixing electronic parts of the present invention is heated from room temperature to 150 ± 20 ° C. in 60 ± 30 seconds, and kept at 150 ± 20 ° C. for 70 ± 30 seconds.
The temperature is raised from 150 ± 20 ° C to 230 ± 20 ° C in ± 10 seconds, and from 230 ± 20 ° C to 170 ± 10 in 40 ± 20 seconds.
It is preferable that the horizontal spread rate (hereinafter, also simply referred to as spread rate) when cooled to ℃ is 20 to 50%, and the vertical sag rate (hereinafter, also simply referred to as sag rate) is 60 to 90%. , More preferably, the spread rate is 20 to 40.
% And the sag rate are 70 to 85%. If the spread ratio is less than 20%, there is a problem that sinking of the electronic component due to the melting of the solder and self-alignment are likely to be insufficient, and misalignment and poor grounding are likely to occur.
If it is larger, there is a problem that the adhesive tends to spread to the electrodes of the substrate, and soldering failure is likely to occur, particularly when a small chip component is soldered to the substrate and fixed with an adhesive. Further, when the sag rate is less than 60%, there is a problem that the sinking of the electronic component due to the melting of the solder is apt to be insufficient, and a poor grounding is liable to occur. When the chip component is soldered and fixed with an adhesive, there is a problem that the adhesive easily spreads to the electrodes of the substrate, and soldering failure is likely to occur.

[0007] The adhesive of the present invention has the above-mentioned properties, and as long as it has such properties, it can be used as an adhesive suitable for the purpose of the present invention. As an example of a preferred component composition of the adhesive of the present invention, for example, the adhesive of the present invention comprises (1) a bisphenol A type epoxy resin and / or a bisphenyl F type epoxy resin, (2) a reaction diluent, (3) an acid hydrazide-based curing agent, (4) an alkyl urea-based curing accelerator and / or a urea adduct-based curing accelerator, (5) an organic rheology additive, and (6) an inorganic filler. It is. The bisphenol A type epoxy resin has an epoxy equivalent of 170 to 230 and 2
Preferred is a liquid at 5 ° C. The bisphenol F type epoxy resin has an epoxy equivalent of 150 to 185.
And a liquid at 25 ° C. is preferred. When a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin is used, the weight mixing ratio is 40: 6.
0 to 60:40 is preferred. If the weight mixing ratio of the two is out of the above range, crystallization may occur, which is not preferable.

Examples of the reaction diluent include n-butyl glycidyl ether, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, styrene oxide, phenyl glycidyl ether, cresyl glycidyl ether, p. sec-butylphenyl glycidyl ether,
Glycidyl methacrylate, vinylcyclohexene monoepoxide, α-pinene oxide, tertiary carboxylic acid glycidyl ester, monoepoxide such as diglycidyl ether, (poly) ethylene glycol diglycidyl ether, (poly) propylene glycol diglycidyl ether, butanediol diglycidyl Examples thereof include ethers, vinylcyclohexene dioxide, neoepenyl glycol diglycidyl ether, and diepoxides such as diglycidylaniline. The preferable amount of the reactive diluent is 1 to 50 parts by weight, more preferably 5 to 20 parts by weight, based on 100 parts by weight of the epoxy resin.

Examples of the acid hydrazide-based curing agent include those which are solid at 25 ° C., for example, adipic dihydrazide, sebacic dihydrazide, succinic dihydrazide, dodecane diacid dihydrazide, eicosane diacid dihydrazide, hexadecane diacid dihydrazide, isophthalic acid. Dihydrazide and the like can be mentioned. The preferred compounding amount of the acid hydrazide-based curing agent is 1.
0 to 0.7, more preferably 1.0 to 0.8. When dicyandiamide is used as a curing agent, there is a problem that moisture resistance is deteriorated, and when an imidazole-based compound is used, storage stability is deteriorated. Examples of the alkylurea-based curing accelerator include those which are solid at 25 ° C., for example, phenyldimethylurea such as 3- (3,4-dichlorophenyl) -1,1-dimethylurea, toluenebisdimethylurea, and methylenebisdimethylurea. And the like. Examples of the urea adduct-based curing accelerator include those in a solid state at 25 ° C., for example, “Fujicure FXB-1050” (manufactured by Fuji Kasei Kogyo Co., Ltd.). The preferred compounding amount of the alkyl urea-based curing accelerator and / or urea adduct-based curing accelerator is based on 100 parts by weight of the epoxy resin.
0.1 to 5.0 parts by weight, more preferably 0.5 to 3.0 parts by weight.
Parts by weight.

Examples of the organic rheology additive include various conventionally known ones having a melting point of 150 ° C. or lower, such as a modified castor oil rheology additive and an organic amide rheology additive. If the melting point is higher than 150 ° C., there is a problem that the spread of the adhesive becomes insufficient and a ground failure is likely to occur. The preferred melting point of the organic rheological additive is 150 to 60 ° C, more preferably 1 to 60 ° C.
00-70 ° C. The preferred amount of the organic rheological additive is 1 to 100 parts by weight of the epoxy resin.
To 20 parts by weight, more preferably 3 to 10 parts by weight.
As the inorganic filler, various types of conventionally known inorganic fillers can be used, and particularly, flaky ones can be preferably used. Examples of such an inorganic filler include talc, calcined talc, and mica, and preferably calcined talc. The preferred compounding amount of the inorganic filler is 5 to 150 parts by weight, more preferably 10 to 100 parts by weight, based on 100 parts by weight of the epoxy resin.

To the adhesive of the present invention, if necessary, an appropriate amount of a conventional auxiliary component such as an inorganic rheological additive, a surfactant, a silane coupling agent, and a coloring agent can be added.

The adhesive of the present invention is used as an adhesive for temporarily fixing an electronic part when an electronic part is fixed to a printed circuit board via solder and an adhesive. In this case, the basic operation for fixing the electronic component to the substrate can be performed according to a conventionally known method.

A preferred method for fixing an electronic component on a substrate using the adhesive of the present invention and a conventional cream solder will be described. First, solder is applied to a predetermined position on a substrate. In this case, the solder is applied on the electrodes on the substrate. The application of the solder can be performed by various conventionally known methods, for example, screen printing.
Next, an adhesive is applied to a predetermined location on the substrate. In this case, the adhesive is usually applied between the electrode portions on the substrate. The application of the adhesive is performed by a conventionally known method, for example, through a nozzle of a dispenser. Next, after the application of the solder and the adhesive to the substrate is completed, predetermined electronic components are mounted. This mounting can be performed by a conventionally known method. That is, the electrode portion (lead wire) of the electronic component is located on the solder application portion, and the non-electrode portion of the electronic component is located on the adhesive application portion. In the mounting process of the electronic component, the electronic component is temporarily fixed on the substrate, although the electronic component has a weak adhesive force due to the adhesive force of the adhesive.

Next, the substrate on which the electronic components are mounted as described above is placed in a heating furnace of a reflow device, where the substrate is heated. The heating of the substrate in this case can be performed by a conventionally known method. By this heating, the solder and the adhesive on the substrate are heated, and the solder melts, while the adhesive starts to harden and gradually hardens.
The heating temperature in this case is the temperature at which the solder melts,
In this case, the substrate is preferably heated from room temperature to 150 ° C. ± 20 ° C. in 60 ± 30 seconds, and heated to 70 ± 30 ° C.
Keep at 150 ± 20 ° C for 150 seconds and 150 ± 30 seconds for 30 ± 10 seconds.
This is performed in a heating step of raising the temperature from ± 20 ° C. to 230 ± 20 ° C. In the heating step, as the solder melts and the liquid adhesive has the above-mentioned curing characteristics, it gradually cures over time, and finally becomes a solid solidified product. Thus, the electronic component is fixed to the substrate. That is, the electrode portion of the electronic component mounted on the substrate sufficiently sinks into the molten solder due to the weight of the electronic component and the surface tension of the molten solder, and at the same time, the electronic component self-aligns and its hardening proceeds. And is finally fixed on the substrate with the strong adhesive force of the adhesive.

Next, the substrate heated as described above is heated from 230 ± 20 ° C. to 170 ± 10 ° C. in 40 ± 20 seconds.
C. and the molten solder is solidified.

After the electronic components have been fixed to the surface of the substrate as described above, the substrate is turned over as necessary, and the electronic components are similarly fixed to the rear surface of the substrate. be able to. The adhesive of the present invention starts its curing at a temperature lower than the melting temperature of the solder and gradually hardens from a liquid state to a solid state when the solder is melted while maintaining its fluidity. When the solder is melted, it does not hinder the lead wires of the electronic parts from sinking into the molten solder, and prevents the electronic parts from gradually sinking on the adhesive applied material by their own weight, thereby performing self-alignment. It does not hinder, and finally cures sufficiently when the solder is melted. Thereby, the electronic component is fixed on the substrate with a strong adhesive force. That is, by using the adhesive of the present invention, the electronic component can be smoothly fixed on the substrate without causing displacement, grounding failure, soldering failure, and the like. Further, when the adhesive of the present invention is used, since the adhesive force between the electronic component and the substrate is strong, when the substrate is turned upside down and the electronic component is fixed on the back surface, the electronic component becomes heavy. Even if there is something, it will not drop out.

[0017]

Next, the present invention will be described in more detail with reference to examples.

Example 1 Composition No. 1 in Table 1 Using the adhesive of No. 1, an electronic component was fixed on a substrate by the following steps. (1) Adhesive coating step After applying cream solder on an electrode (copper foil) on a printed circuit board by an ordinary method, an adhesive is applied between the electrodes by a dispenser by an ordinary method. (2) Electronic Component Mounting Step Next, the electronic component is mounted on the substrate by an ordinary method. That is,
The lead wire of the electronic component is brought into contact with the solder (ground), and the main body of the electronic component is brought into contact with the adhesive applied material. (3) Heating Step The substrate is placed in a heating furnace, and hot air is blown against the substrate surface, the temperature is raised from room temperature to 150 ° C. in 60 seconds, kept at 150 ° C. for 70 seconds, and reduced from 150 ° C. to 230 in 30 seconds. ° C
Temperature to melt the solder. By the heating,
The solder on the substrate is melted, and the lead wires of the electronic component sink into the solder due to the weight of the electronic component and the surface tension of the solder. On the other hand, the adhesive applied material starts to be cured by the heating, gradually cures, and sufficiently cures in the heating step. In this case, the adhesive increases the adhesive strength as the curing progresses, and when sufficiently cured, becomes solid and firmly fixes the electronic component on the substrate. Since the adhesive of the present invention gradually cures while maintaining its fluidity, the lead wire of the electronic component may sink into the molten solder before the adhesive becomes a solid cured product. The sinking of the lead wire of the electronic component into the molten solder is not hindered. Further, sinking of the electronic component into the adhesive applied material due to its own weight is not hindered. (4) Cooling Step After the heating, the substrate is blown by an air fan by a conventional method.
After cooling from 230 ° C. to 170 ° C. in 40 seconds, it is cooled to room temperature, whereby solidification of the molten solder occurs, and the lead wire of the electronic component is fixed to the electrode portion of the substrate. According to the method of fixing the electronic component to the substrate (mounting method),
Since the melting of the solder occurs before the adhesive hardens to a solid state, the adhesive is substantially prevented from sinking the lead wires of the electronic component into the molten solder and sinking due to the weight of the electronic component itself. However, the electronic component can be securely fixed on the substrate.

Table 1 shows the curing time, spread rate (%), sag rate (%), solderability and part holding properties of the composition. These characteristics were measured and evaluated as follows. (Curing time (= gelling time)) In accordance with JIS C 2104, take 0.4 ml of the adhesive sample in a recess on a hot plate at 150 ± 1.5 ° C. and 170 ± 1.5 ° C., and stir with a stirring rod. The mixture was stirred at a rate of 60 ± 5 times / min, and the time required for the sample to lose tackiness and not to draw a string was defined as a curing time (= gelling time). (Spread rate (%)) Adhesive sample (sample temperature 28 ° C)
A dispenser with a nozzle tip inner diameter of 1.0 mm ("KP-4
80 "(manufactured by JUKI) with a diameter of 1.6 mm (n
= 10) and 1.0 mm (n = 10) so that a solder resist and a pre-flux are applied thereon to a length of 100 mm × width 114 mm × thickness 1.6 m.
m on a glass epoxy substrate, and this is coated in a UV reflow oven (“TMF-101”, manufactured by Sanyo Electric Co., Ltd.).
The temperature was raised from room temperature to 150 ° C. in 0 seconds, and 150 ° C. for 70 seconds.
The temperature was raised from 150 ° C to 230 ° C in 30 seconds, cooled from 230 ° C to 170 ° C in 40 seconds, and then cooled to room temperature to reduce the diameter of the coating material formed on the substrate to 0.1 ° C.
Measured with an optical microscope with a scale that can measure 5 mm,
The spread rate (%) of the adhesive was calculated as follows, and the average value was calculated. Spreading rate (%) = (BA) / A × 100 A: Diameter of adhesive applied immediately after application B: Diameter of cured adhesive after curing (Sag rate (%)) Adhesive sample (sample temperature) 28 ° C.) with a dispenser (“KP-48
0 "(manufactured by JUKI) and the coated material diameter is 1.6 mm (n =
10) A solder resist and a pre-flux are coated on the solder resist so as to have a circular shape of 10).
A 14 mm x 1.6 mm thick glass epoxy substrate was coated, and this was applied to a UV reflow heating furnace ("TMF-10").
1 ", manufactured by Sanyo Electric Co., Ltd.), the temperature was raised from room temperature to 150 ° C. in 60 seconds, kept at 150 ° C. for 70 seconds, and reduced to 1 in 30 seconds.
The temperature was raised from 50 ° C to 230 ° C, cooled from 230 ° C to 170 ° C in 40 seconds, then cooled to room temperature, and the height of the coating material formed on the substrate was measured with a micrometer capable of measuring 0.01 mm. It measured, the sag rate (%) of the adhesive was calculated as follows, and the average value was calculated. Sag rate (%) = (C−D) / C × 100 C: height of adhesive applied immediately after application D: height of cured adhesive after curing (solderability) Solder resist and Pre-flux coated 100mm long x 114mm wide x
A predetermined amount of cream solder having a melting point of 183 ° C. is applied on an electrode of a glass epoxy substrate having a thickness of 1.6 mm, and then the adhesive sample is dispensed with a dispenser (“KP-480”, JUKI Co., Ltd.) and applied to four places (= 8 points) so that the diameter of the applied material is 0.7 mm (two points with 0.9 mm pitch), the lead pitch is 15 mm square, the lead pitch is 0.5 mm, and the number of pins Is mounted such that the electrode portion of the 100-pin QFT is located on the cream solder application portion and the non-electrode portion is located on the adhesive application portion, and this is mounted in a reflow heating furnace with UV (“TMF-101”, Sanyo Temperature from room temperature to 150 ° C in 60 seconds,
Incubate at 150 ° C for 30 seconds, and from 150 ° C to 230 in 30 seconds.
The temperature was raised to 230 ° C., cooled from 230 ° C. to 170 ° C. in 40 seconds, then cooled to room temperature, and the solderability was evaluated according to the following criteria. ○: Sinking of QFT and self-alignment are sufficient,
There is no poor grounding or misalignment. ×: The sinking of QFT and the self-alignment are insufficient, and there are poor grounding and misalignment. (Part holding property) The solderability was reversed so that the QFT was below the substrate, reprocessed under the same heating and cooling conditions as in the solderability evaluation test, and the component characteristics were evaluated according to the following criteria. ：: There is no change in the QFT holding state before and after reheating. ×: QFT was dropped, poor ground contact, or misalignment occurred. The contents of the components shown in Table 1 are as follows.

Epoxy resin (ZX-1059): trade name "ZX-1059", an equal weight mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin manufactured by Tobu Kasei Co., epoxy equivalent 165, viscosity 2000 cps
(25 ° C.) Reactive diluent (NEOTOT E): trade name “NEOTOT E”, tertiary carboxylic acid glycidyl ester manufactured by Tobu Kasei Co., epoxy equivalent 240-265, viscosity 5-20 cps
(25 ° C.) Curing agent (ADH): trade name “ADH”, adipate dihydrazide manufactured by Otsuka Chemical Co., Ltd. Curing accelerator (FXB-1050): trade name “Fujicure FXB-1050”, manufactured by Fuji Chemical Co., Ltd., urea adduct system Curing accelerator, average particle size 5 μm Curing accelerator (Omicure 52): trade name “Omicure 5”
2 ", methylene diphenylbisdimethylurea manufactured by Omicron Chemical Co., Ltd., average particle size: 10 μm or less Organic rheology additive (THIXCIN-R): trade name“ THIXCIN-R ”, hydrogenated castor oil manufactured by RHEOX, white fine powder, melting point 86 Organic rheological additive (Tallen XA-79): trade name "Tallen XA-79", a fatty acid amide wax-based rheological additive manufactured by Kyoeisha Chemical Co., white powder, melting point 1
60 ° C. Inorganic filler (Enstack 24): trade name “Enstack 24”, talc manufactured by Asada Flour Milling Co., Ltd. (talc fired at 1100 ° C. and made enstatite), average particle size 3.0
μm

[0021]

[Table 1]

[0022]

By using the adhesive of the present invention, electronic components can be smoothly fixed to a printed circuit board without problems such as poor grounding, misalignment, and poor soldering.

Claims (3)

[Claims] 1. A thermosetting adhesive for temporarily fixing an electronic component, which is used in a method for fixing an electronic component to a printed circuit board via cream solder and a thermosetting adhesive for temporarily fixing an electronic component. (I) the curing time at 170 ° C. is 80 to 200 seconds; (ii) 15
That the curing time at 0 ° C. is 400 to 800 seconds;
(iii) It is heated from room temperature to 150 ± 20 ° C. in 60 ± 30 seconds.
The temperature is kept at 150 ± 20 ° C for 70 ± 30 seconds, and the temperature is raised from 150 ± 20 ° C to 230 ± 20 ° C in 30 ± 10 seconds, and 230 ± 20 ° C to 170 ± 10 ° C in 40 ± 20 seconds. A thermosetting adhesive for temporary fixing of electronic components, characterized in that the rate of spread in the horizontal direction when cooled down to 20 to 50% and the sag rate thereof is 60 to 90%. 2. The thermosetting adhesive for temporarily fixing an electronic component includes a bisphenol A type epoxy resin and / or a bisphenol F type epoxy resin, a reactive diluent, an acid hydrazide type curing agent, and an alkyl urea type curing agent. The thermosetting adhesive according to claim 1, which is a liquid epoxy resin composition comprising an accelerator and / or a urea adduct-based curing accelerator, an organic-based rheological additive, and an inorganic filler. 3. A method for fixing an electronic component to a printed circuit board, wherein (i) applying cream solder and the thermosetting adhesive for temporarily fixing the electronic component according to claim 1 or 2 to the printed circuit board; (Ii) mounting the electronic component such that the electrode portion of the electronic component is located on the cream solder application portion and the non-electrode portion of the electronic component is located on the adhesive application portion;
ii) The temperature of the cream solder and the adhesive applied on the substrate in the heating furnace is raised from room temperature to 150 ± 20 ° C. in 60 ± 30 seconds, kept at 150 ± 20 ° C. for 70 ± 30 seconds, and 30 ± 10 seconds. A step of raising the temperature from 150 ± 20 ° C. to 230 ± 20 ° C. to melt the cream solder and gradually cure the adhesive;
Cooling from ± 20 ° C. to 170 ± 10 ° C. and solidifying.