JP2001170798A - Flux for soldering, solder paste, electronic part device, electronic circuit module, electronic circuit device and soldering method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flux and solder paste for soldering capable of sufficiently dealing with the higher density of packaging, the miniaturizing of parts, narrower pitch of the arrangement spacings of the parts, etc., with sufficient strength of joining and a soldering method. SOLUTION: The flux 3 contains an adhesive resin and a hardener. This flux or the solder paste containing the same is applied on a part mounting substrate 1 and the electronic parts 4 are mounted thereon and are soldered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a soldering flux, a solder paste, an electronic component device, an electronic circuit module, an electronic circuit device, and a soldering method.

[0002]

2. Description of the Related Art For example, in soldering a component to a component mounting board, a flux is used as is well known. The main function of the flux is to remove the oxide film on the surface of the metal conductor provided on the component mounting board and the metal for soldering the component, thereby improving the wettability of the solder. As the flux, those containing rosin as a main component are best known. Rosin contains abietic acid,
A carboxylic acid such as levobimaric acid is contained, and the function of the carboxyl group removes an oxide film on the surface of the metal to be soldered.

[0003] In addition to the above-mentioned rosin, the flux generally contains a solvent,
Various additives such as a plasticizer or a thixotropic agent are blended.
For example, Japanese Patent Application Laid-Open No. 11-121915 discloses that
A type of flux that is adjusted by adding alcohol is disclosed.

Further, as another flux, an RMA (halogen-free) flux defined by a mill standard is also known. In the case of this flux, after reflow
The step of cleaning flux and the like is omitted.

[0005] After the above-mentioned flux is soldered,
Independent of the bonding of the soldered components, the solder joint is achieved by the fusion joining of the solder metal. Therefore, the joint strength between the metals to be soldered depends on the solder joint area.

However, in various electronic devices, as high-density mounting has progressed, components have been reduced in size and the pitch between components has been narrowed, and accordingly, the solder joint area has been rapidly narrowed. Even at this stage, it is already difficult to secure sufficient soldering strength. Furthermore, the trend toward higher mounting density, miniaturization of components, and narrower pitch of component placement tend to progress further, and conventional means of securing solder joint strength only by the solder joint area responds to this technical trend. Is increasingly difficult to do.

In general, as means for securing the solder joint strength, a means for forming a solder fillet portion and increasing the solder joint area between a terminal of a component and a conductor (land or solder bump) on a component mounting board is employed. ing. However, in high-density mounting, the joint area of the fillet portion is reduced, so that it is difficult to employ a means for increasing the joint strength by the fillet portion.

Further, for example, in various electronic circuit modules, a component mounting board of a double-sided mounting type is used, and components are soldered on one side of the component mounting board using high-temperature solder (furnace passing) and then on the other side. Mount the parts and ventilate again.
Therefore, when soldering components on the other side of the component mounting board, it is necessary to use low-temperature solder having a lower melting point than the high-temperature solder on the one side. Conventionally, the melting point of the solder has generally been adjusted by the Pb content.

However, from the viewpoint of global environmental protection, Pb
Is required (Pb-free solder)
The development of such solder compositions has been actively pursued. However, a Pb-free solder composition having a high-temperature melting point comparable to that of a conventional high-temperature solder has not been put to practical use at present. The reason is that the melting point of the Pb-free solder itself is around 220 ° C., which is about 40 ° C. higher than that of the eutectic solder, so that no alternative composition other than Pb can be found. For this reason, in a double-sided component mounting board, the difference in melting point of the solder used on both sides cannot be sufficiently obtained, and when mounting the component on the component mounting board, the component floats or falls off. Will occur.

Furthermore, in an electronic circuit module using a semiconductor chip, after the semiconductor chip is soldered to the chip mounting substrate, a sealing agent is poured into the bonding interface, and the semiconductor chip and the chip mounting substrate are sealed with the sealing agent. An operation of bonding and fixing is added.

However, if a residue of the flux remains when the sealing agent is injected, the sealing agent does not sufficiently reach the interface between the semiconductor chip and the substrate due to the flux, and the adhesive force cannot be exhibited. Therefore, a step of cleaning the flux before injecting the sealing agent is added. The washing of the flux is usually performed in several steps using a volatile organic solvent. However, the use of volatile organic solvents has been regulated for the purpose of environmental protection, etc.
This is a heavy burden process in terms of both cost and environmental protection.

Further, when the electronic circuit module obtained as described above is mounted on a mother substrate to form an electronic circuit device, a combination using a ceramic for a chip mounting substrate and an organic resin substrate for a mother substrate. In
In a thermal shock test or the like after mounting, due to the difference in the coefficient of thermal expansion between the ceramic substrate and the organic resin substrate, shrinkage stress is concentrated at the solder joint, cracks are likely to occur, and the joint life is short. Therefore, to improve the solder joint strength,
Although it is desired to inject a sealant, it is not actually performed to subject the entire mother substrate to a flux cleaning step and a sealant injection step, since this considerably increases the cost.

[0013]

SUMMARY OF THE INVENTION An object of the present invention is to provide a soldering device capable of coping with high-density mounting, downsizing of components, and narrowing of arrangement intervals of components with sufficient bonding strength. And a solder paste and a soldering method.

Another object of the present invention is to provide a component mounting board of a double-sided mounting type that can reliably prevent a component from floating or falling off even if the difference in the melting points of the solders used on both sides is not sufficiently obtained. An object of the present invention is to provide a soldering flux, a solder paste, and a soldering method.

Still another object of the present invention is to provide an electronic component device, an electronic circuit module, and an electronic circuit device which do not require a flux cleaning step and are inexpensive to manufacture.

Still another object of the present invention is to provide a highly reliable electronic component device, an electronic circuit module, and an electronic circuit device in which the life of the solder joint is significantly prolonged as compared with the conventional art.

[0017]

In order to solve the above-mentioned problems, a soldering flux according to the present invention contains an adhesive resin and a curing agent.

Since the flux according to the present invention contains an adhesive resin and a curing agent, the adhesive resin can function as an adhesive for fixing the component mounting board to the component after soldering. For this reason, it is possible to prevent the components from peeling or falling off due to impact or thermal stress, and to improve the reliability of the solder joint. This point is significantly different from the conventional rosin flux having no bonding function after soldering.

Moreover, by using the flux according to the present invention, a sufficient fixing strength can be ensured even without a fillet portion. For this reason, it is not necessary to provide a region for generating a fillet portion in the component connection conductor (land) formed on the component mounting board, so that the mounting density can be improved.

In the flux according to the present invention, as the adhesive resin, a resin having a high adhesive strength can be selected from a large number of resin materials according to the temperature, and this can be used as the adhesive resin. Therefore, after the components were soldered on the first side of the component mounting board of the double-sided mounting type using the flux according to the present invention, the reflow furnace was passed through the reflow furnace using normal eutectic solder on the second side of the component mounting board. Even 1
The components mounted on the surface do not cause problems such as shifting, Manhattan phenomenon (component standing phenomenon) or dropping. Of course, the flux according to the present invention can be used in both the first and second soldering processes.

The flux according to the present invention can be in the form of a liquid or a paste. Such a flux can be easily applied to a component mounting substrate or the like by means such as printing, dispenser application, spraying, and brushing.

In the flux according to the present invention, a preferable adhesive resin is a thermosetting resin. Specific examples of the thermosetting resin include at least one selected from an epoxy resin, a phenol resin, a polyimide resin, a silicone resin, a modified resin, and an acrylic resin. The types and amounts of the exemplified resin materials can be selected according to the bonding temperature range, the target film hardness, and the like.

The curing agent may be any as long as it cures the adhesive resin. Preferably, it contains a carboxylic acid. The curing agent containing a carboxylic acid has not only a hardening action on the thermosetting resin but also a flux action for removing an oxide film on the surface of the metal to be soldered.

The flux according to the present invention may contain a solvent, a plasticizer, a thixotropic agent and the like. The solvent is added to adjust the curing temperature and the curing speed of the adhesive resin and to adjust the viscosity according to the application form. Plasticizers and thixotropic agents are also added to adjust the viscosity depending on the form of application. The amounts of the solvent, plasticizer, thixotropic agent and the like are selected according to the purpose of use.

The flux according to the present invention comprises an adhesive resin,
It may be in the form of microcapsules enclosing an organic acid, carboxylic acid, solvent or curing agent that provides a reducing action.

Further, the flux according to the present invention can be mixed with a solder powder and used for forming a solder paste. Solder powder is Sn, Cu, Ag, S
b, Pb, In, Zn and Bi. To obtain a Pb-free solder paste, the solder powder is composed of a solder powder other than Pb.

The present invention further discloses an electronic component device, an electronic circuit module and an electronic circuit device using the above-mentioned flux. First, an electronic component device according to the present invention includes at least one electronic component, a component mounting board, and a soldering flux. The electronic component is soldered on a component mounting board. The soldering flux contains an adhesive resin and a curing agent, is interposed between the electronic component and the component mounting board, and adheres the two.

The soldering flux interposed between the electronic component and the component mounting board contains an adhesive resin and a curing agent, and functions as an adhesive. This soldering flux does not need to be washed and can be used as it is as an adhesive soldering flux. Therefore, it is possible to obtain an electronic component device that does not require a flux cleaning step and has a low manufacturing cost. In addition, since the soldering flux contains an adhesive resin and a hardening agent and functions as an adhesive, a highly reliable electronic component device with a significantly longer solder joining life than before has been developed. Obtainable.

Next, an electronic circuit module according to the present invention includes a semiconductor chip, a chip mounting board, and a soldering flux. The semiconductor chip includes at least one semiconductor element and is soldered on a chip mounting substrate. The soldering flux contains an adhesive resin and a curing agent, is interposed between the semiconductor chip and the chip mounting board, and adheres the two.

The soldering flux interposed between the semiconductor chip and the chip mounting board contains an adhesive resin and a curing agent, and functions as an adhesive.
This soldering flux does not need to be washed and can be used as it is as an adhesive soldering flux. Therefore, it is possible to obtain an electronic circuit module which does not require a flux cleaning step and has a low manufacturing cost. In addition, since the soldering flux contains an adhesive resin and a hardening agent and functions as an adhesive, a highly reliable electronic circuit module with a significantly longer solder joining life than before has been developed. Obtainable.

Further, an electronic circuit device according to the present invention includes an electronic circuit module, a mother board, and a soldering flux. The electronic circuit device is soldered on the mother board. The soldering flux contains an adhesive resin and a curing agent, is interposed between the semiconductor chip and the mother substrate, and adheres the two. This soldering flux does not need to be washed and can be used as it is as an adhesive soldering flux. Therefore, since a flux cleaning step is not required, an electronic circuit device having a low manufacturing cost can be obtained. In addition, since the soldering flux contains an adhesive resin and a hardening agent and functions as an adhesive, a highly reliable electronic circuit device with a significantly longer solder joining life than before has been developed. Obtainable.

The present invention further discloses a soldering method using the above-mentioned flux and solder paste.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <Flux and electronic component device> Example 1 Bisphenol A was used as a thermosetting resin, and carboxylic anhydride was used as a curing agent. The mixing ratio of the thermosetting resin and the curing agent was 1: 1 by weight. Further, a small amount of a solvent and a thixotropic agent were blended in order to secure the viscosity.

The flux 3 prepared with the above composition is applied to the component mounting board 1 on which the solder bumps 21 and 22 have been applied in advance.
(See FIG. 1 (a)) and applied (see FIG. 1 (b)). Next, as shown in FIG. 1C, a chip-shaped electronic component 4 having a length of 1 mm and a width of 0.5 mm was mounted. The electronic component 4 has end electrodes 41 and 42 at opposite ends of the base 40.
And the end electrodes 41 and 42 are solder bumps 21 and 22
It was arranged on the component mounting board 1 so as to be positioned above. The component mounting board 1 on which the electronic component 4 was mounted was passed through a reflow furnace, and end electrodes 41 and 42 provided at both ends of the base 40 of the electronic component 4 were soldered to the solder bumps 21 and 22. Thereby, the electronic component device according to the present invention is obtained. The flux 3 includes the electronic component 4 and the component mounting board 1
And functions as an adhesive soldering flux. As for the obtained electronic component device, as shown in FIG. 2, the electronic component 4 was pushed in the lateral direction F1, and the component lateral pressing strength was measured.

Comparative Example 1 For comparison, a conventional rosin-based flux was used, and FIG.
The components are mounted according to and soldering is performed.
According to the test method shown in FIG. 2, the lateral pressing strength of the component was measured.

FIG. 3 shows the results of the lateral pressing strength test.
As shown in FIG. 3, the average lateral pressing strength of Comparative Example 1 using the conventional rosin flux was about 800 g,
In Example 1 using the flux according to the present invention, an average lateral pressing strength of about 1600 g could be obtained.

The flux filled in the space generated between the electronic component 4 and the component mounting board 1 is composed of an adhesive resin,
It contains a curing agent and functions as an adhesive. This flux (flux for soldering) 3 does not need to be washed and can be used as it is as a flux for adhesive soldering. Therefore, it is possible to obtain an inexpensive electronic component device that does not require a flux cleaning step. Moreover, since the soldering flux composed of the flux 3 contains an adhesive resin and a curing agent and functions as an adhesive soldering flux, the solder joining life is significantly prolonged as compared with the conventional soldering flux. As a result, a highly reliable electronic component device can be obtained.

Example 2 A solder paste was prepared by mixing the flux prepared in Example 1 and a solder powder. The mixing amount of the flux with respect to the solder powder was 10 wt%. Using this solder paste, a chip component was soldered on a component mounting board. 4A to 4C show details of the component mounting board,
It is a fragmentary sectional view showing the soldering process of a chip part to a parts mounting board. The component mounting board 1 includes a Cu film 51.
(52), Ni film 61 (62) and Au film 71 (72)
Are sequentially laminated to form two lands.

On the land of the component mounting board 1 described above,
The solder paste 81 (82) according to the present invention was applied (see FIG. 4A). When applying the solder paste 81 (82), printing was performed using a metal mask having a thickness of 100 μm. The opening size of the metal mask is 0.5mm x
0.3 mm, which is the same as the land size on which the electronic component 4 is mounted.

Then, the electronic component 4 having a length of 1 mm and a width of 0.5 mm is mounted on the solder paste 81 (82) (see FIG. 4B), and is passed through a reflow furnace.
The electronic component 4 was soldered onto the component mounting board 1 (FIG. 4).
(C)). Thereby, the electronic component device according to the present invention is obtained.

Thereafter, the lateral pressing strength was measured according to the method shown in FIG. In FIG. 4C, reference numeral 3 is
The flux according to the present invention included in the solder paste 81 (82) is shown as a fillet outside the end electrodes 41 and 42.

Comparative Example 2 For comparison, a chip component was soldered to a component mounting board using a conventional solder paste containing a rosin-based flux. The blending amount of the rosin flux with respect to the solder powder was 10 wt%.

FIGS. 5A to 5C are partial cross-sectional views showing details of the component mounting board and a step of soldering chip components to the component mounting board. As illustrated, the component mounting board 1 has two lands in which a Cu film 51 (52), a Ni film 61 (62), and an Au film 71 (72) are sequentially stacked. A solder paste 91 (92) containing a rosin-based flux was applied onto the lands of the component mounting board 1 (see FIG. 5A).

Then, on the solder paste 91 (92) containing the rosin-based flux, a length of 1 mm and a width of 0.1 mm are applied.
The electronic component 4 of 5 mm was mounted (see FIG. 5B) and passed through a reflow furnace to solder the electronic component 4 onto the component mounting board 1 (see FIG. 5C). After this,
According to the method shown in FIG. 2, the lateral pressing strength of the component was measured.

FIG. 6 is a diagram showing the results of the lateral pressing strength test of the components of Example 2 and Comparative Example 2. As shown in the figure, the average value of the lateral pressing strength of Comparative Example 2 was about 600 g,
In Example 2, an average strength of about 1500 g could be obtained.

Example 3 The flux prepared in Example 1 and the solder powder were mixed to prepare a solder paste. The mixing amount of the flux with respect to the solder powder was increased to 20 to 45 wt%.

Using this solder paste, the electronic component 4 was mounted on the component mounting board 1 and soldered according to FIG. Specifically, referring to FIG. 7, the component mounting board 1 includes a Cu film 51 (52), a Ni film 61 (62),
It has two lands formed by sequentially stacking u films 71 and 72 (see FIG. 7A).

On the land of the component mounting board 1 described above,
The solder paste 81 (82) according to the present invention was applied (see FIG. 7A). When applying the solder paste 81 (82), printing was performed using a metal mask having a thickness of 100 μm. The opening size of the metal mask is 0.5mm x
0.3 mm, which is the same as the land size on which the electronic component 4 is mounted.

Then, the electronic component 4 having a length of 1 mm and a width of 0.5 mm is mounted on the solder paste 81 (82) (see FIG. 7B), and is passed through a reflow furnace.
The electronic component 4 was soldered onto the component mounting board 1 (FIG. 7).
(C)). Thereby, the electronic component device according to the present invention is obtained.

The appearance after soldering is as shown in FIG. FIG. 8 is a sectional view taken along line 8-8 in FIG. In the third embodiment, a solder paste whose flux content is intentionally increased is used. However, the solder amount is substantially small, and the electronic component 4 is, as shown in FIG.
Soldered in normal condition without tilting. In FIG. 7C and FIG. 10, reference numeral 3 indicates the flux according to the present invention included in the solder paste 81 (82), which becomes a fillet outside the end electrodes 41 and 42.

Further, by using the solder paste containing the flux according to the present invention, the periphery of the electronic component 4 after soldering was covered with the flux, and the improvement of the lateral pressing strength of the component was also recognized. Thus, by intentionally improving the flux content in the solder paste, the thickness of the solder can be controlled by the solder paste.
In particular, in the region where the flux content is 35 wt% or more,
Diagonal soldering was avoided, and a bonding strength equal to or higher than that of the conventional product was obtained.

Comparative Example 3 For comparison, the electronic component 4 was mounted on the component mounting board 1 and soldered according to FIG. 9 using a conventional rosin-based flux-containing solder paste. More specifically, referring to FIG. 9, the component mounting board 1 includes a Cu film 51 (5
2), two lands formed by sequentially laminating a Ni film 61 (62) and an Au film 71 (72) (FIG. 9).
(A)).

On the land of the component mounting board 1 described above,
Rosin flux-containing solder paste 91 (92)
Was applied (see FIG. 9A). Solder paste 91
In the application of (92), printing was performed using a metal mask having a thickness of 100 μm. The opening size of the metal mask was 0.5 mm × 0.3 mm, and was the same as the land size on which the electronic component 4 was mounted.

Then, the electronic component 4 having a length of 1 mm and a width of 0.5 mm is mounted on the solder paste 91 (92) (see FIG. 9B) and passed through a reflow furnace.
The electronic component 4 was soldered onto the component mounting board 1 (FIG. 9).
(C)).

The appearance after reflow soldering is as shown in FIG. FIG. 10 is a partial cross-sectional view along the line 10-10 in FIG. 9C. As shown in FIG. 10, when the conventional rosin flux-containing solder was soldered, the amount of solder was too large, and the electronic component 4 was obliquely soldered. In FIG. 9C and FIG. 10, reference numeral 93 indicates a rosin-based flux contained in the solder paste 91 (92).

Example 4 The composition of the flux was examined. Liquid epoxy resin was used as the adhesive resin, and abietic acid (carboxylic acid) was used as the curing agent. Abietic acid was added to the liquid epoxy resin at a weight ratio shown in Table 1. This flux was applied on a substrate and passed through a reflow oven at 230 ° C. to verify the cured resin film.

As shown in Table 1, the liquid epoxy resin 1w
When the mixing ratio of abietic acid is 1 wt% with respect to t%, a hard cured film is obtained, and the best result is obtained. Other compounding ratios are not suitable because they do not cure, become gel-like, or become elastic cured films. With respect to the reflow temperature, if the mixing ratio of the epoxy resin, or the molecular weight and the number of functional groups of the epoxy resin are changed and the type of the curing agent (carboxylic acid) is examined, the desired cured film (adhesive ) Can be obtained.

Example 5 A solder paste was prepared by mixing the flux prepared in Example 4 with solder powder. As solder powder,
Sn (96.5) Ag (3.5) was used. The content of the flux was 25 wt%. This is Example 5.

FIG. 11 shows the reflow temperature and the component lateral pressing strength when the chip component is soldered using the solder paste of Example 5 and when the chip component is soldered using the conventional rosin-based solder paste. FIG. In the drawing, a curve L1 shows the characteristics when the solder paste of Example 5 is used, and a curve L2 shows the characteristics when the conventional rosin-based solder paste is used.

As shown in FIG. 11, the solder paste containing the flux exhibits higher bonding strength than the conventional rosin-based solder paste in the reflow temperature range of 220 to 260 ° C. In particular, high bonding strength could be secured at a reflow temperature of 230 ° C. or higher.

Example 6 Using the solder paste shown in Example 5, a chip component was soldered to a component mounting board to obtain an electronic component device according to the present invention. Thereafter, when the bonding property between the component mounting board and the terminal electrode of the chip component was observed, the solder paste containing the flux had the same bonding property as the rosin-based solder paste. By the way, when the conventional conductive adhesive and anisotropic conductive paste were evaluated in the same manner as the above-mentioned flux, joining of the component mounting board and the terminal of the component was not obtained.

In the above embodiment, the electronic component 4 is mounted on one surface of the component mounting board 1, but the electronic component 4 can be mounted on both surfaces of the component mounting board 1. in this case,
After performing a soldering process using the solder paste according to the present invention on one surface of the component mounting board 1, the component mounting board 1
On the other side, the electronic component 4 can be soldered using a solder different from the solder paste according to the present invention, for example, a conventional rosin-based solder paste. Alternatively, the electronic component 4 can be soldered on both sides of the component mounting board 1 using the solder paste according to the present invention. In any case, the electronic component 4 does not cause a problem such as shifting, a Manhattan phenomenon (component standing phenomenon), or falling off.

<Electronic Circuit Module> The electronic circuit module according to the present invention differs from the above-described electronic component device in that the electronic component is replaced by a semiconductor chip and the component mounting board is replaced by a chip mounting board. Apart from, there is essentially no difference. In other words, the basic configuration of the electronic circuit module according to the present invention is substantially disclosed in the electronic component device. The semiconductor chip used is not particularly limited. The semiconductor chip generally includes a semiconductor element (not shown) or a passive circuit element. An electronic circuit module called a chip size package (CSP) can of course be used.

FIG. 12 is a partial front sectional view of an electronic circuit module according to the present invention. The illustrated electronic circuit module includes a semiconductor chip 100 and a chip mounting substrate 200.
And a soldering flux 400. The illustrated semiconductor chip 100 has an appropriate number of terminal electrodes 110 and 120 formed at appropriate positions such as a lower surface, and the terminal electrodes 110 and 120 are attached to the chip mounting substrate 200 by solders 210 and 220. Upper lands 230, 240
It is joined to.

The chip mounting substrate 200 can be constituted by a ceramic substrate, an organic resin substrate, or a combination thereof. Generally, a single-layer or multiple-layer conductor pattern is provided inside the chip mounting substrate 200, and
Via holes and the like provided in the thickness direction are formed.
The conductor pattern is provided merely for circuit routing, and may be provided for forming a capacitor or an inductor.

The soldering flux 400 contains an adhesive resin and a curing agent, is interposed between the semiconductor chip 100 and the chip mounting board 200, and adheres them. The soldering flux 400 functions as an adhesive.

In the illustrated embodiment, the soldering flux 400 comprises the semiconductor chip 100 and the chip mounting substrate 2.
It is filled so as to substantially fill the gap between the two.

As described above, the soldering flux 400 does not need to be cleaned, and can be used as it is as an adhesive. Therefore, it is possible to obtain an electronic circuit module which does not require a flux cleaning step and has a low manufacturing cost. Moreover, the soldering flux is
Since it contains an adhesive resin and a curing agent and functions as an adhesive, it is possible to obtain a highly reliable electronic circuit module in which the solder joining life is significantly prolonged as compared with the related art.

FIG. 13 is a view for explaining a method of soldering an electronic circuit module such as a CSP (chip size package) shown in FIG. This soldering method is shown in FIG.
Corresponds to a method applied to soldering of an electronic circuit module. As already mentioned,
Flux 400 containing adhesive resin and curing agent
Is applied in advance on the chip mounting substrate 200 on which the solder bumps 210 and 220 have been formed. Solder bump 21
Reference numerals 0 and 220 are formed on lands 230 and 240 provided on the surface of the chip mounting substrate 200. The details of the flux 400 are as described above.

Then, the semiconductor chip 100 is mounted on the chip mounting substrate 200. Semiconductor chip 100
Means that the terminal electrodes 110 and 120 are solder bumps 210 and 2
20 and is arranged on the chip mounting board 200. Thereafter, the chip mounting substrate 200 on which the semiconductor chip 100 is mounted is passed through a reflow furnace, and the terminal electrodes 11 provided on both ends of the base 40 of the semiconductor chip 100 are provided.
0 and 120 are soldered to the solder bumps 210 and 220. Thereby, the electronic circuit module shown in FIG. 12 is obtained.

FIG. 14 is a partial front sectional view showing another example of the electronic circuit module according to the present invention. In the figure, the same components as those shown in FIG. 12 are denoted by the same reference numerals. In the illustrated embodiment, the soldering flux 400 is interposed between the semiconductor chip 100 and the chip mounting substrate 200,
Around 0 and 220, both are bonded.

Also in this case, the soldering flux 40
0 does not need to be washed and can be used as an adhesive as it is. Therefore, it is possible to obtain an electronic circuit module which does not require a flux cleaning step and has a low manufacturing cost. In addition, since the soldering flux contains an adhesive resin and a hardening agent and functions as an adhesive, a highly reliable electronic circuit module with a significantly longer solder joining life than before has been developed. Obtainable.

FIG. 15 is a view for explaining a method of soldering the electronic circuit module shown in FIG. This soldering method corresponds to a method in which the soldering method shown in FIGS. 4 to 8 is applied to soldering of an electronic circuit module.
Flux 410, 4 containing solder powder having the composition already described
20 is applied on lands 230 and 240 provided on the surface of the chip mounting substrate 200 in advance.

Then, the semiconductor chip 100 is mounted on the chip mounting substrate 200. Semiconductor chip 100
Are arranged on the chip mounting substrate 200 such that the terminal electrodes 110 and 120 are positioned on the solder powder-containing fluxes 410 and 420. The chip mounting substrate 200 on which the semiconductor chip 100 is mounted is passed through a reflow furnace, and the terminal electrodes 110, 1
20 is soldered by the solder components contained in the solder powder-containing fluxes 410 and 420.

In the joined state, the adhesive resin and the curing agent contained in the solder powder-containing fluxes 410 and 420 are interposed between the semiconductor chip 100 and the chip mounting board 200, and around the solder bumps 210 and 220, Glue. Thereby, the electronic circuit module shown in FIG. 14 is obtained. In FIG. 15, by increasing the amount of the solder powder-containing fluxes 410 and 420, FIG.
As shown in the figure, the soldering flux 400 is
A structure in which the gap between the semiconductor chip 100 and the chip mounting substrate 200 is filled so as to substantially fill the gap can also be realized.

Next, specific examples and comparative examples will be described.

Example 7 First, a solder paste containing a thermosetting flux having the following composition was prepared.

Flux: Bisphenol A resin / phthalic anhydride mixed at a mass ratio of 1: 1 and a solvent added by 10% by mass Solder powder: Sn-3.5Ag mass%
At a rate of The composition of the solder powder can be selected according to the reflow temperature, and another composition system may be used. Also,
The amount of the flux can also be arbitrarily selected.

The above-mentioned solder paste containing a thermosetting flux was applied on an organic chip mounting substrate by a screen printing method. In screen printing, a metal master screen having a thickness of 100 μm was used.

Next, the semiconductor chip on which the solder bumps were formed was previously mounted on an organic chip mounting substrate and passed through a reflow furnace. Reflow temperature up to 240 ° C
The furnace passing time at 220 ° C. or more was 30 seconds.

Comparative Example 7 For comparison, a conventional product using a sealing agent and a conventional product using no sealing agent were prepared.

<Test> The electronic circuit module according to Example 7 and two types of conventional electronic circuit modules were subjected to a thermal shock test. The thermal shock test was carried out at (-155 ° C.) for 0.5 hour, and then at (+ 125 ° C.) for 0.5 hour. Thereafter, the direct current resistance (RDC) at the solder connection part was measured.

FIG. 16 is a graph showing the results of RDC measurement. In FIG. 16, the horizontal axis represents the thermal shock cycle (cycle), and the vertical axis represents RDC (Ω). Characteristic L
11 is the characteristic of the conventional product without using the sealant, characteristic L12 is the characteristic of the conventional product using the sealant, and characteristic L13 is the characteristic of Example 7 according to the present invention.

In FIG. 16, in the conventional product without using the sealing agent, as shown by the characteristic L11, the RDC sharply increased after 1500 cycles, and the RD
C has deteriorated. On the other hand, in the seventh embodiment according to the present invention, as shown by the characteristic L13, no deterioration of the RDC was observed even after the lapse of 2000 cycles. this is,
This is equivalent to the characteristic L12 of the conventional product using the sealing agent.

<Electronic Circuit Device> The electronic circuit device according to the present invention is different from the above-described electronic component device in that the electronic component is replaced by an electronic circuit module and the component mounting board is replaced by a mother board. Apart from that, there is essentially no difference. In other words, the basic configuration of the electronic circuit device according to the present invention is substantially disclosed in the electronic component device.

FIG. 17 is a front partial sectional view of an electronic circuit device according to the present invention. The illustrated electronic circuit device includes an electronic circuit module 300, a mother board 500, and a soldering flux 600.

As the electronic circuit module 300, a conventional type electronic circuit module can be used, but preferably the one having the structure shown in FIGS. In the electronic circuit module 300, an appropriate number of terminal electrodes 250, 260 are formed at appropriate positions such as the lower surface, and these terminal electrodes 250, 260 are connected to the solder bumps 510, 520.
The lands 530, 54 on the mother substrate 500
0.

The mother substrate 200 can be constituted by a ceramic substrate, an organic resin substrate, or a combination thereof. Inside the mother substrate 500, a conductor pattern of a single layer or a plurality of layers, a via hole provided in a thickness direction, or the like may be formed. The conductor pattern is provided merely for circuit routing, and may be provided for forming a capacitor or an inductor.

The soldering flux 600 contains an adhesive resin and a curing agent, and contains the electronic circuit module 300.
And the mother substrate 500, and are bonded to each other. The soldering flux 600 functions as an adhesive. In the illustrated embodiment, the soldering flux 600 includes the electronic circuit module 300 and the mother board 5.
It is filled so as to substantially fill the gap between the two.

The soldering flux 600 does not need to be cleaned, and can be used as it is as an adhesive. Accordingly, it is possible to obtain an electronic circuit device which does not require a flux cleaning step and has a low manufacturing cost. In addition, since the soldering flux contains an adhesive resin and a hardening agent and functions as an adhesive, a highly reliable electronic circuit device with a significantly longer solder joining life than before has been developed. Obtainable.

FIG. 18 is a view for explaining a method of soldering the electronic circuit device shown in FIG. This soldering method corresponds to a method in which the soldering method shown in FIG. 1 is applied to soldering of an electronic circuit device. As described above, the flux 60 containing the adhesive resin and the curing agent is used.
0 is applied on the mother substrate 500 on which the solder bumps 510 and 520 have been formed in advance. The flux 600 does not contain solder powder.

The solder bumps 510 and 520 are formed on lands 530 and 540 provided on the surface of the mother board 500. Then, the electronic circuit module 300 is mounted on the mother board 500. The electronic circuit module 300 is configured such that the terminal electrodes 250 and 260 are located on the solder bumps 510 and 520,
Place on top of 00. The mother board 500 on which the electronic circuit module 300 is mounted is passed through a reflow furnace, and the terminal electrodes 250 and 260 of the electronic circuit module 300 are soldered to the solder bumps 510 and 520. Thereby, the electronic circuit device shown in FIG. 17 is obtained.

FIG. 19 is a partial front sectional view showing another example of the electronic circuit device according to the present invention. In the figure, the same components as those shown in FIG. 17 are denoted by the same reference numerals. In the illustrated embodiment, the soldering flux 600 is interposed between the electronic circuit module 300 and the mother board 500, and the solder bumps 510, 5
Around 20, the two are glued.

In this case, too, the soldering flux 60 is used.
0 does not need to be washed and can be used as an adhesive as it is. Accordingly, it is possible to obtain an electronic circuit device which does not require a flux cleaning step and has a low manufacturing cost. Moreover, since the soldering flux 600 contains an adhesive resin and a curing agent in addition to the solder powder and functions as an adhesive, the solder joining life is significantly extended compared to conventional soldering fluxes. A reliable electronic circuit device can be obtained.

FIG. 20 is a view for explaining a method of soldering the electronic circuit device shown in FIG. This soldering method corresponds to a method in which the soldering method shown in FIGS. 4 to 8 is applied to soldering of an electronic circuit device. Solder powder-containing fluxes 610, 62 prepared with the composition already described.
0 is applied on lands 530 and 540 provided on the surface of the mother substrate 500 in advance. Then, the electronic circuit module 300 is mounted on the mother board 500. The electronic circuit module 300 includes terminal electrodes 250, 2
60 is arranged on the mother substrate 500 such that the 60 is located on the solder powder-containing fluxes 610 and 620.

Next, the mother board 500 on which the electronic circuit module 300 is mounted is passed through a reflow furnace, and the terminal electrodes 250 and 260 provided on the electronic circuit module 300 are provided.
Is soldered with the solder components contained in the solder powder-containing fluxes 610 and 620. The adhesive resin and the curing agent contained in the solder powder-containing fluxes 610 and 620 are interposed between the electronic circuit module 300 and the mother board 500, and adhere the two around the solder bumps 510 and 520. Thus, the electronic circuit device shown in FIG. 19 is obtained. In FIG. 20, by increasing the amount of the flux 610, 620 containing the solder powder, FIG.
As shown in FIG. 7, the soldering flux 600
However, it is also possible to realize a structure in which a gap between the electronic circuit module 300 and the mother board 500 is substantially filled.

Next, a specific example will be described.

Example 8 First, a solder paste containing a thermosetting flux having the following composition was prepared.

Flux: Bisphenol A resin / phthalic anhydride mixed at a mass ratio of 1: 1 and a solvent added by 10% by mass. Solder powder: Sn-3.5Ag. mass%
At a rate of The composition of the solder powder can be selected according to the reflow temperature, and another composition system may be used. Also,
The amount of the flux can also be arbitrarily selected.

As the mother substrate, an organic mother substrate was used. As the electronic circuit module, an organic chip mounting substrate was used, on which a semiconductor chip was mounted. Au plating was applied to the surface of the terminal electrode provided on the lower surface of the organic chip mounting substrate so that it could be soldered to the organic mother substrate.

The above-mentioned solder paste containing a thermosetting flux was applied on an organic chip mounting substrate by a screen printing method. In screen printing, a metal master screen having a thickness of 100 μm was used.

Next, the electronic circuit module was mounted on an organic mother substrate and passed through a reflow furnace. The reflow temperature was set to a maximum temperature of 240 ° C., and the furnace passing time of 220 ° C. or more was set to 30 seconds.

Example 9 An electronic circuit device was manufactured in the same manner as in Example 8, except that the chip mounting substrate of the electronic circuit module was a ceramic substrate.

Comparative Example 8 A chip mounting substrate of an electronic circuit module was made of an organic material, and this electronic circuit module was soldered to an organic mother substrate using a conventional flux. On the surface of the terminal electrode provided on the lower surface of the organic chip mounting board, so that it can be soldered to the organic mother board,
Au plating was performed.

Comparative Example 9 A chip mounting board of an electronic circuit module was made of a ceramic material, and this electronic circuit module was soldered to an organic mother board using a conventional flux. Au plating was applied to the surface of the terminal electrode provided on the lower surface of the ceramic chip mounting substrate so that it could be soldered to the organic mother substrate.

<Test> The electronic circuit modules according to Examples 8 and 9 and the conventional electronic circuit modules according to Comparative Examples 8 and 9 were subjected to a thermal shock test. The thermal shock test was (
° C) for 0.5 hours, then (+ 125 ° C) to 0.5
This was held for one hour, and this was taken as one cycle, and was performed up to 2000 cycles. Thereafter, the direct current resistance (RDC) at the solder connection part was measured.

FIG. 21 is a graph showing the results of RDC measurement. In FIG. 21, the horizontal axis represents the thermal shock cycle (cycle), and the vertical axis represents RDC (Ω). Characteristic L
Reference numeral 21 denotes the characteristic of Comparative Example 9, and characteristic L22 denotes the characteristic of Examples 8, 9 and Comparative Example 8.

In FIG. 21, in Comparative Example 9 in which the chip mounting substrate of the electronic circuit module is made of a ceramic material and the mother substrate is made of an organic material, as shown by the characteristic L21, when the number of cycles exceeds 1,000, the RDC is reduced. It increases rapidly and RDC deteriorates. On the other hand, in the eighth and ninth embodiments according to the present invention, as shown by the characteristic L22, 200
No RDC degradation was observed even after 0 cycles. In particular, the characteristic L22 of Example 9 and the characteristic L of Comparative Example 9
As is clear from the comparison with No. 21, when the chip mounting substrate of the electronic circuit module is a ceramic substrate and the mother substrate is an organic resin substrate, the RDC has been remarkably deteriorated in the past (see characteristic L21). According to the present invention,
Even in such a combination of substrates, an excellent effect that deterioration of RDC can be prevented (see characteristic L22) can be obtained.

Although illustration is omitted, when the solder paste according to the present invention is used, the flux according to the present invention is used as a sealant, and the electronic component and the component mounting substrate, the semiconductor chip and the chip mounting substrate, and the electronic circuit module and the mother board are used. The substrate can also be joined by a sealing agent made of flux. Further, in the component mounting board using the flux according to the present invention, a general sealing agent can be formed on the upper layer of the flux.

[0110]

As described above, according to the present invention, the following effects can be obtained. (A) To provide a soldering flux, a solder paste, and a soldering method capable of coping with high bonding density, miniaturization of components, and narrowing of arrangement intervals of components with sufficient bonding strength. be able to. (B) It is possible to provide a soldering flux, a solder paste, and a soldering method that can reliably prevent a problem such as floating or falling off of a component on a component mounting board of a double-sided mounting type. (C) It is possible to provide an electronic component device, an electronic circuit module, and an electronic circuit device which do not require a flux cleaning step and are inexpensive to manufacture. (D) It is possible to provide a highly reliable electronic component device, an electronic circuit module, and an electronic circuit device in which the life of the solder joint is significantly prolonged as compared with the related art.

[Brief description of the drawings]

FIG. 1 is a partial sectional view illustrating a method for soldering a chip component using a flux according to the present invention.

FIG. 2 is a partial cross-sectional view showing a method of testing the lateral pressing strength of a chip component soldered to a component mounting board.

FIG. 3 is a diagram showing a result of a lateral pressing strength test of the part shown in FIG. 2;

FIG. 4 is a partial cross-sectional view showing details of a component mounting board and a step of soldering a chip component to the component mounting board when a solder paste containing a flux according to the present invention is used.

FIG. 5 shows details of a component mounting board when a conventional solder paste containing a rosin-based flux is used;
It is a fragmentary sectional view showing the soldering process of a chip part to a parts mounting board.

6 is a diagram showing the results of a component lateral pressing strength test for the soldering method according to the present invention shown in FIG. 4 and the conventional soldering method shown in FIG.

FIG. 7 is a partial cross-sectional view showing a soldering method using a solder paste containing a flux according to the present invention.

8 is a view showing an appearance when the chip component is soldered on the component mounting board by the soldering method according to the present invention shown in FIG. 7, and a portion along the line 8-8 in FIG. 7; It is sectional drawing.

FIG. 9 is a partial cross-sectional view showing a conventional soldering method using a rosin-based flux-containing solder paste.

10 is a view showing the appearance when the chip component is soldered on the component mounting board by the conventional soldering method shown in FIG. 9, and is a partial cross-sectional view along the line 10-10 in FIG. 9; It is.

FIG. 11 is a graph showing the relationship between the reflow temperature and the component lateral pressing strength when a chip component is soldered using the solder paste according to the present invention and when a chip component is soldered using a conventional rosin-based flux-containing solder paste. It is a figure showing a relation.

FIG. 12 is a front partial sectional view of an electronic circuit module according to the present invention.

13 is a diagram illustrating a method of soldering the electronic circuit module shown in FIG.

FIG. 14 is a front partial sectional view showing another example of the electronic circuit module according to the present invention.

15 is a diagram illustrating a method of soldering the electronic circuit module shown in FIG.

FIG. 16 is a graph showing RDC measurement results.

FIG. 17 is a front partial sectional view of an electronic circuit device according to the present invention.

18 is a diagram illustrating a method of soldering the electronic circuit device shown in FIG.

FIG. 19 is a front partial sectional view showing another example of the electronic circuit device according to the present invention.

20 is a diagram illustrating a method of soldering the electronic circuit device shown in FIG.

FIG. 21 is a graph showing an RDC measurement result.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Component mounting board 21 and 22 Solder bump 3 Flux 4 Chip component 81 and 82 Solder paste

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H05K 3/34 512 H05K 3/34 512C // B23K 1/00 330 B23K 1/00 330E F-term (reference) 5E319 AA03 AA07 AB05 BB05 BB07 BB11 5F044 LL01 LL04 LL11 RR17 RR18 RR19

Claims (24)

[Claims] 1. A soldering flux containing an adhesive resin and a curing agent. 2. The flux according to claim 1, wherein the flux is a liquid or a paste. 3. The flux according to claim 1, wherein the adhesive resin contains a thermosetting resin. 4. The flux according to claim 3, wherein the thermosetting resin is an epoxy resin, a phenol resin,
A flux containing at least one selected from a polyimide resin, a silicone resin, a modified resin, and an acrylic resin. 5. The flux according to claim 4, wherein the curing agent contains a carboxylic acid. 6. A solder paste containing a solder powder and a flux, wherein the flux is as defined in any one of claims 1 to 5, wherein the solder powder is mixed with the flux. Have solder paste. 7. The solder paste according to claim 6, wherein the solder powder is Sn, Cu, Ag, Sb, Pb, Ib.
A solder paste containing at least one selected from n, Zn, and Bi. 8. An electronic component device comprising at least one electronic component, a component mounting board, and a soldering flux, wherein the electronic component is soldered on the component mounting board, An electronic component device, wherein the attaching flux contains an adhesive resin and a curing agent, is interposed between the electronic component and the component mounting board, and adheres both. 9. The electronic component device according to claim 8, wherein the soldering flux contains a thermosetting resin. 10. The electronic component device according to claim 9, wherein the thermosetting resin is an epoxy resin, a phenol resin,
An electronic component device including at least one selected from a polyimide resin, a silicon resin, a modified resin, and an acrylic resin. 11. The electronic component device according to claim 8, wherein the curing agent contains a carboxylic acid. 12. A semiconductor chip, a chip mounting board,
An electronic circuit module including a soldering flux, wherein the semiconductor chip includes at least one semiconductor element, and is soldered on a chip mounting board, wherein the soldering flux includes an adhesive resin and And a curing agent, interposed between the semiconductor chip and the chip mounting substrate and bonding the two. 13. The electronic circuit module according to claim 12, wherein the soldering flux contains a thermosetting resin. 14. The electronic circuit module according to claim 13, wherein the thermosetting resin is an epoxy resin, a phenol resin,
An electronic circuit module including at least one selected from a polyimide resin, a silicon resin, a modified resin, and an acrylic resin. 15. The electronic circuit module according to claim 12, wherein the curing agent contains a carboxylic acid. 16. An electronic circuit device including an electronic circuit module, a motherboard, and a soldering flux, wherein the electronic circuit module is soldered on the motherboard, and the soldering flux is provided. Is an electronic circuit device that contains an adhesive resin and a curing agent, is interposed between the semiconductor chip and the chip mounting substrate, and adheres both. 17. The electronic circuit device according to claim 16, wherein the electronic circuit module is the electronic circuit device according to any one of claims 12 to 15. 18. The electronic circuit device according to claim 16, wherein the adhesive resin includes a thermosetting resin. 19. The electronic circuit device according to claim 18, wherein the thermosetting resin is an epoxy resin, a phenol resin,
An electronic circuit device including at least one selected from a polyimide resin, a silicon resin, a modified resin, and an acrylic resin. 20. The electronic circuit device according to claim 16, wherein the curing agent contains a carboxylic acid. 21. A method of soldering using the flux according to claim 1. 22. A method of soldering using the solder paste according to claim 6. 23. The method according to claim 20, wherein an electronic component, an electronic circuit module, or a semiconductor chip is soldered on the substrate. 24. The method according to claim 23, wherein a soldering process using the solder paste is performed on one surface of the substrate, and then the solder paste is formed on the other surface of the substrate. Is a soldering method including a step of soldering electronic components using different solders.