JP4130271B2 - Mounting structure and manufacturing method thereof - Google Patents

Description

【００３２】
（注１）接着剤層構成；電子部品と基板とを電気的に接続する導電性接着剤層の構成
・熱硬化；熱硬化性導電性接着剤
・熱可塑；熱可塑性導電性接着剤
（注２）接着剤材料；導電性接着剤の組成
・アミノ；導電性接着剤のバインダ樹脂としてアミノ基を含有したエポキシ樹脂を使用
・イミノジ酢酸；導電性接着剤のバインダ樹脂としてイミノジ酢酸基を含有したエポキシ樹脂を使用
（注３）接着剤層サイズ；導電性接着剤層のサイズ
・熱硬化＞熱可塑；熱可塑性の導電性接着剤層の径が熱硬化性の導電性接着剤層の径以上（熱硬化性の導電性接着剤層；直径＝１．５ｍｍ、熱可塑性の導電性接着剤層；直径＝１．０ｍｍ）
（Ｃ）試料である実装構造体の評価試験方法
〔試験１〕実装後における電子部品の取り外し性評価試験
基板を固定し、接続部を２００℃の温度で局所的に加熱しつつ、真空吸着ノズルを利用して電子部品を上方に引き上げ、部品が基板から分離するまでに要する時間を測定した
〔試験２〕基板のリサイクル性評価試験
試験１が終了後の基板をイソプロピルアルコール溶液中に６０分浸漬し、導電性接着剤の残渣の有無を目視で評価した
〔試験３〕実使用時における信頼性評価試験
基板を固定しておき、圧縮試験機を利用して電子部品をその側方から加圧し、電子部品が基板から外れる際に作用している力を測定した
【００３３】
【表２】

【００３４】
そして、表２で示した試験結果によると、以下のような事実が確認される。すなわち、本形態に係る実装構造体（参考例１〜８）では、電子部品１と基板２との電気的接続を熱硬化性の導電性接着剤層３と熱可塑性の導電性接着剤層４とで確保しているので、従来の形態に係る実装構造体（比較例１，比較例２）よりも実装後における電子部品１の取り外し性が改善されている。また、熱可塑性の導電性接着剤層４を基板２側に配置してなる実装構造体（参考例２）では、基板２のリサイクル性が向上している。
【００３５】
さらに、導電性接着剤層３，４の少なくとも一方が樹脂と化学反応し易い官能基であるアミノ基を含有している実装構造体（参考例３〜参考例５）や、金属を吸着し易い官能基であるイミノジ酢酸基を含有している実装構造体（参考例６〜参考例８）、あるいは、導電性接着剤層３，４のディメンジョン（接着剤層サイズ）が改良された実装構造体（実施例１）であれば、実使用時における信頼性が向上していることも分かる。
【００３６】
なお、ここでは、樹脂と化学反応し易い官能基がアミノ基であり、金属を吸着し易い官能基がイミノジ酢酸基であるとしているが、樹脂と化学反応し易い官能基が、カルボキシル基、ビニル基、エポキシ基、アミノ基、メタクリル基、メルカプト基のうちから選択された少なくとも１種であってよく、また、金属を吸着し易い官能基が、モノカルボキシル基、ジカルボキシル基、アミノカルボキシル基、イミノジプロピオン酸基、エチレンジアミンジ酢酸基のうちから選択された少なくとも１種であってもよいことは勿論である。
【００３７】
さらにまた、以上の説明では、実装構造体を構成する電子部品１がセラミックコンデンサであり、基板２がガラスエポキシ基板であるとしているが、このような構成に限られることはなく、他の構成とされた実装構造体、例えば、半導体チップとキャリア基板との実装構造体やリード部品、ベアチップ部品、パッケージ部品などのような表面実装型の電子部品からなる実装構造体に対しても本発明の適用が可能であることは明らかである。
【００３８】
【発明の効果】
以上説明したように、本発明に係る実装構造体によれば、電子部品の電極と基板の電極とを電気的に接続する２層の導電性接着剤層のうちの一方を熱硬化性の導電性接着剤層とし、その他方を熱可塑性の導電性接着剤層としているので、熱硬化性及び熱可塑性それぞれの導電性接着剤層同士が互いの短所を補完しあって両者の長所が互いに強調されることとなる結果、リペアが可能であるとともに、十分に高い実装信頼性をも確保できるという効果が得られる。そして、本発明に係る製造方法によれば、リペアが可能であり、かつ、高い実装信頼性を確保することが可能な実装構造体を容易に作製し得ることとなる。
【００３９】
さらに、本発明によれば、以下のように、耐衝撃性が向上するという効果も得られる。すなわち、従来の実装構造体では、比較的硬い（弾性率の高い）熱硬化性接着剤のみを用いていたため、落下などの衝撃が加わった場合の接着界面にストレスが集中し、界面剥離によって不良が発生することがあったが、本発明に係る実装構造体はヤング率の低い塑性層を有しており、衝撃が加わった場合のストレスが塑性層によって吸収されるため、不良が発生しないことになる。
【図面の簡単な説明】
【図１】 参考の形態に係る実装構造体を示す断面図である。
【図２】 実施の形態に係る実装構造体を示す断面図である。
【図３】 参考例に係る実装構造体を示す断面図である。
【図４】 参考例に係る実装構造体を示す断面図である。
【図５】 実施例に係る実装構造体を示す断面図である。
【図６】 従来の形態に係る第１の実装構造体を示す断面図である。
【図７】 従来の形態に係る第２の実装構造体を示す断面図である。
【図８】 比較例に係る実装構造体を示す断面図である。
【図９】 比較例に係る実装構造体を示す断面図である。
【符号の説明】
１ 電子部品
２ 基板
３ 熱硬化性の導電性接着剤層
４ 熱可塑性の導電性接着剤層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mounting structure and a manufacturing method thereof, and more particularly, to a mounting structure in which an electronic component and a substrate are integrated using a conductive adhesive, and a manufacturing method thereof.
[0002]
[Prior art]
In recent years, there is a growing trend to raise the awareness of environmental harmony and to eliminate the use of lead-containing solder used when mounting electronic components. To meet these demands, lead-free solder with low lead content is required. Development of a mounting structure configured by using a lead, that is, a mounting structure in which an electrode of an electronic component and an electrode of a substrate are electrically connected with lead-free solder is actively performed. Although some of these mounting structures have already been put into practical use, there are problems such as eliminating the influence on weak heat-resistant components due to an increase in mounting temperature and realizing lead-free component electrodes. There are many things left behind.
[0003]
On the other hand, there are not many reports of mounting structures configured using conductive adhesives instead of lead-containing solder, but if the configuration uses conductive adhesives, there are advantages other than environmentally friendly measures. It is believed to be secured. First, since the processing temperature of the conductive adhesive is about 150 ° C. and lower than that of solder, it is easy to realize low cost and high performance of the mounting structure. Second, Since the specific gravity of the conductive adhesive is about half that of the solder, the weight of the mounting structure can be further reduced, and thirdly, since metal such as solder is not used, metal fatigue is caused. There are advantages such as no occurrence and excellent mounting reliability.
[0004]
[Problems to be solved by the invention]
By the way, as such a conductive adhesive, a thermosetting or thermoplastic one is generally used, and as a mounting structure, as shown in FIG. 6, electrodes (not shown) of the electronic component 1 and the substrate 2 are used. Are electrically connected via a thermosetting conductive adhesive layer 3 or, as shown in FIG. 7, the electrodes of the electronic component 1 and the substrate 2 are heated. One that is electrically connected via the plastic conductive adhesive layer 4 is conceivable. However, in the case of the thermosetting conductive adhesive layer 3, there is a problem that it is difficult to replace, that is, repair, the electronic component 1 after being mounted on the substrate 2. That is, the thermosetting conductive adhesive contains a monomer thermosetting resin as a binder, and the heated monomer forms a network polymer to be cured. Even if the adhesive is softened, the adhesive is not softened, and the mounted electronic component 1 cannot be removed from the substrate 2.
[0005]
On the other hand, in the case of the thermoplastic conductive adhesive layer 4, the conductive adhesive is composed of a composition in which a polymer thermoplastic resin is dispersed in a solvent, and the solvent evaporates with heating. Therefore, it can be softened by reheating or contact with a solvent, and the electronic component 1 after mounting can be easily removed from the substrate 2. However, when a thermoplastic conductive adhesive is used, and particularly when a mounting structure in which the flip chip type electronic component 1 is mounted on the substrate 2 is formed, the electronic component 1 and the substrate 2 face each other. The conductive adhesive is placed in the narrow space that occurs, and the solvent is difficult to evaporate as a result of curing the conductive adhesive in a sealed environment. Only a weak connection state can be obtained, and high mounting reliability cannot be ensured.
[0006]
The present invention has been made in view of these disadvantages, and an object of the present invention is to provide a mounting structure that can be repaired and that can secure sufficiently high mounting reliability, and a manufacturing method thereof.
[0007]
[Means for Solving the Problems]
In the mounting structure according to claim 1 of the present invention, the electrode of the electronic component and the electrode of the substrate are electrically connected via two conductive adhesive layers, and the electrode side of the electronic component Is a mounting structure in which a thermosetting conductive adhesive layer is disposed, and a thermoplastic conductive adhesive layer is disposed on the electrode side of the substrate. The adhesive layer covers the thermoplastic conductive adhesive layer and reaches the electrode of the substrate. Further, the thermosetting conductive adhesive layer and the thermoplastic conductive adhesive layer Is characterized by direct contact .
[0010]
A mounting structure according to a second aspect of the present invention is the mounting structure according to the first aspect , wherein at least one of the thermosetting conductive adhesive layer and the thermoplastic conductive adhesive layer includes a resin and It contains a functional group that easily undergoes a chemical reaction.
[0011]
The mounting structure according to a third aspect of the present invention is the mounting structure according to the second aspect , and the functional group that easily reacts with the resin includes a carboxyl group, a vinyl group, an epoxy group, an amino group, a methacryl group, and a mercapto group. It is characterized by being at least one selected from among them.
[0012]
A mounting structure according to a fourth aspect of the present invention is the mounting structure according to the first aspect , wherein at least one of the thermosetting conductive adhesive layer and the thermoplastic conductive adhesive layer is made of metal. It contains a functional group that easily adsorbs and a filler metal .
[0013]
The mounting structure according to a fifth aspect of the present invention is the mounting structure according to the fourth aspect , and the functional group that easily adsorbs a metal includes a monocarboxyl group, a dicarboxyl group, an aminocarboxyl group, an iminodiacetic acid group, and an iminodipropion. It is at least one selected from an acid group and an ethylenediaminediacetic acid group.
[0014]
In the method for manufacturing a mounting structure according to claim 6 of the present invention, a thermoplastic conductive adhesive layer is printed on a substrate electrode and cured, and the thermosetting conductive layer is formed on the thermoplastic conductive adhesive layer. This is a method for manufacturing a mounting structure in which an electrode of an electronic component is mounted on a thermosetting conductive adhesive layer after the conductive adhesive layer is printed, and then the thermosetting conductive adhesive layer is cured. The thermosetting conductive adhesive layer covering the thermoplastic conductive adhesive layer and reaching the electrode of the substrate, and further, the thermosetting conductive adhesive layer and the thermoplastic conductive layer. The adhesive adhesive layer is in direct contact .
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0017]
Figure 1 is a sectional view showing a configuration of a mounting structure according to the reference embodiment, FIG. 2 is a sectional view showing a configuration of a mounting structure according to the embodiment. The components constituting the mounting structure according to the present embodiment are not fundamentally different from those of the conventional structure. Therefore, in FIGS. 1 and 2, components and portions that are the same as those in FIGS. 6 and 7 are used. Are given the same reference numerals.
[0018]
The mounting structure according to the present embodiment is obtained by integrating an electronic component and a substrate using a conductive adhesive instead of lead-containing solder, and as shown in FIG. (Not shown) and the electrode (not shown) of the substrate 2 are electrically connected to each other through two conductive adhesive layers 3 and 4. One of the two conductive adhesive layers 3 and 4 is a thermosetting conductive adhesive layer 3, and the other is a thermoplastic conductive adhesive layer 4. In FIG. 1, the conductive adhesive layer 3 disposed on the electrode side of the electronic component 1 is thermosetting, whereas the conductive adhesive layer 4 disposed on the electrode side of the substrate 2 is heated. It is supposed to be plastic.
[0019]
In FIG. 1, the thermosetting conductive adhesive layer 3 is disposed on the electronic component 1 side and the thermoplastic conductive adhesive layer 4 is disposed on the substrate 2 side. However, the thermoplastic conductive adhesive layer 4 is disposed on the electronic component 1 side, while the thermosetting conductive adhesive layer 3 is disposed on the substrate 2 side. It may be a configuration. This also applies to each of the mounting structures having other configurations described below. In this case, the thermosetting conductive adhesive and the thermoplastic conductive adhesive themselves are basically not different from the conductive adhesive according to the conventional form, and thus detailed description thereof is omitted here.
[0020]
That is, in the mounting structure having the configuration shown in FIG. 1, the thermosetting conductive adhesive layer 3 is disposed on the electrode side of the electronic component 1, and the thermoplastic conductive material is disposed on the electrode side of the substrate 2. Since the adhesive layer 4 is disposed, when the entire mounting structure is heated to a predetermined temperature or more or brought into contact with an appropriate solvent, the thermoplastic conductive adhesive disposed on the electrode side of the substrate 2 The agent layer 4 becomes soft. Therefore, the mounted electronic component 1 can be easily detached from the substrate 2. Alternatively, when the thermoplastic conductive adhesive layer 4 is softened, the thermosetting conductive adhesive layer 3 and the thermoplastic conductive adhesive layer 4 can be separated at the interface with each other. It is also possible to remove the electronic component 1 in which the conductive conductive adhesive layer 3 is disposed from the substrate 2 in which the thermoplastic conductive adhesive layer 4 is disposed.
[0021]
Therefore, in the mounting structure according to the present embodiment , the electronic component 1 after being mounted on the substrate 2 can be easily replaced, that is, repaired as necessary. In the case of such a configuration, the thermoplastic conductive adhesive layer 4 remains disposed on the substrate 2 after the electronic component 1 is removed. It is possible to re-mount a new electronic component 1 after re-curing the layer 4. Alternatively, since the thermoplastic conductive adhesive layer 4 can be easily removed by immersing the substrate 2 after removing the electronic component 1 in an appropriate solvent, the substrate 2 itself can be easily reused. Benefits are also secured.
[0022]
Furthermore, in the mounting structure according to the present embodiment , the electrodes of the electronic component 1 and the substrate 2 are connected to the two conductive adhesive layers 3, 4, that is, the thermosetting conductive adhesive layer 3 and the heat. Since it is connected with the plastic conductive adhesive layer 4, compared to the case where the electronic component 1 and the substrate 2 are connected with only the thermoplastic conductive adhesive layer 4 as in the prior art, The adhesive strength is greatly increased. That is, at the time of manufacturing the mounting structure having the configuration shown in FIG. 1, the thermoplastic conductive adhesive layer 4 is printed on the electrode of the substrate 2 and then cured, and the substrate 2 at this time is executed. Since the top is not yet closed by the flip-chip type electronic component 1 and remains completely open, the solvent contained as a binder in the thermoplastic conductive adhesive is likely to evaporate, As a result of improving the bulk strength, an adhesive strength sufficient to withstand practical use is ensured.
[0023]
Furthermore, in the mounting structure of FIG. 1, the two conductive adhesive layers 3 and 4 that connect the electrodes of the electronic component 1 and the substrate 2 are in a state of facing each other. It is also possible to adopt the configuration of the embodiment as shown in FIG. That is, the mounting structure according to the configuration of this embodiment is such that the electrode of the electronic component 1 and the electrode of the substrate 2 are electrically connected via the conductive adhesive layers 3 and 4 and are thermally cured. The conductive conductive adhesive layer 3 is disposed on the electronic component 1 side and the thermoplastic conductive adhesive layer 4 is disposed on the substrate 2 side, as in FIG. The conductive adhesive layer 3 is not only facing the thermoplastic conductive adhesive layer 4 but also arranged so as to reach the electrodes of the substrate 2 while covering the conductive adhesive layer 4. Different.
[0024]
And when the structure of such embodiment is employ | adopted, the thermosetting conductive adhesive layer which was excellent in the strength in the thermoplastic conductive adhesive layer 4 which tends to be inferior in strength. Therefore, a mounting structure with increased adhesive strength can be obtained as compared with the configuration of FIG. Even in this case, the bonding area between the electrode of the substrate 2 and the thermosetting conductive adhesive layer 3 does not increase so much, and the bonding state of the substrate 2 with the electrode is a thermoplastic conductive adhesive. Since there is no change in securing with the layer 4, the above-described ease of repair does not occur.
[0025]
By the way, in the mounting structure described above, at least one of the thermosetting conductive adhesive layer 3 and the thermoplastic conductive adhesive layer 4 is a functional group that easily reacts with the resin, for example, It preferably contains a functional group that is at least one selected from a carboxyl group, a vinyl group, an epoxy group, an amino group, a methacryl group, and a mercapto group. That is, since these functional groups have high chemical reactivity with the resin, if either one or both of the conductive adhesive layers 3 and 4 contain these functional groups, both Based on this covalent bond, an even stronger connection state is secured.
[0026]
Further, at least one of the conductive adhesive layers 3 and 4 is a functional group that easily adsorbs a metal, for example, a monocarboxyl group, a dicarboxyl group, an aminocarboxyl group, an iminodiacetic acid group, an iminodipropionic acid group, ethylenediaminediacetic acid. You may contain the functional group which is at least 1 sort (s) selected from group. In this case, the conductive adhesive layers 3 and 4 are firmly bonded to each other through the filler metal contained therein, and as a result, an excellent connection state is secured. It will be.
[0027]
Subsequently, a method for manufacturing a mounting structure according to this embodiment will be described. That is, when the mounting structure shown in FIG. 1 is manufactured, the thermoplastic conductive adhesive layer 4 is printed on the electrode of the substrate 2 and cured, and the cured thermoplastic conductive adhesive layer 4 is cured. After the thermosetting conductive adhesive layer 3 is printed thereon, the electrode of the electronic component 1 is mounted on the thermosetting conductive adhesive layer 3 and then the thermosetting conductive adhesive layer 3 is formed. Curing is performed. When the mounting structure shown in FIG. 2 is manufactured, the thermoplastic conductive adhesive layer 4 is printed on the electrode of the substrate 2 and cured, and then the cured thermoplastic conductive adhesive is used. A thermosetting conductive adhesive layer 3 is printed on the layer 4 so that the conductive adhesive layer 3 covers the thermoplastic conductive adhesive layer 4 and reaches the electrode of the substrate 2. Print. Then, when the electrode of the electronic component 1 is mounted on the printed thermosetting conductive adhesive layer 3 and the thermosetting conductive adhesive layer 3 is cured, the mounting structure is completed. .
[0028]
And if it is these manufacturing methods, the flip-chip-type electronic component 1 has not been arrange | positioned yet, but a thermoplastic conductive adhesive layer on the electrode of the board | substrate 2 which has been opened completely. 4 is cured after printing, and as a result, the solvent contained as a binder in the thermoplastic conductive adhesive is likely to evaporate. As a result, the bulk strength of the thermoplastic conductive adhesive layer 4 is improved and it is practically used. Adhesive strength that can be obtained is ensured. By the way, in the mounting structure according to this embodiment , the thermoplastic conductive adhesive layer 4 is disposed on the electronic component 1 side, and the thermosetting conductive adhesive layer 3 is disposed on the substrate 2 side. However, in the case of manufacturing such a mounting structure, a thermoplastic conductive adhesive layer 4 is printed on the electrode of the electronic component 1 and cured, while a heat is applied to the electrode of the substrate 2. A thermoplastic conductive adhesive layer 4 printed on the curable conductive adhesive layer 3 and cured through the thermosetting conductive adhesive layer 3 is applied to the electrode of the substrate 2. After mounting, the thermosetting conductive adhesive layer 3 is cured.
[0029]
Next, Reference Examples 1 to 8, which are mounting structures according to the present embodiment , Example 1 is based on FIGS. 3 to 5, and Comparative Examples 1 and 2, which are mounting structures according to the conventional mode, are shown in FIG. Each will be described with reference to FIG. First, in this case, each of Reference Examples 1 to 8, Example 1 and Comparative Examples 1 and 2 has a basic configuration and a changed part as shown in (A) below, and the following ( Suppose that it is produced by the manufacturing method as shown in B). In FIGS. 3 to 5 and FIGS. 8 and 9 showing the mounting structure as a sample, reference numeral 1 is an electronic component, 2 is a substrate, 3 is a thermosetting conductive adhesive layer, and 4 Is a thermoplastic conductive adhesive layer.
[0030]
(A) Mounting structure as a sample [basic structure]
・ Electronic component: Ceramic capacitor (3026 size), solder plating electrode ・ Substrate: Glass epoxy substrate, gold plating electrode ・ Constitution of conductive adhesive layer: 2 layers ( Reference Examples 1-8, Example 1 )
-Composition of conductive adhesive;
Thermoplastic conductive adhesive; flaky Ag powder (95 wt%) + thermoplastic epoxy resin Thermosetting conductive adhesive; flaky Ag powder (85 wt%) + thermosetting epoxy resin ・ Conductive adhesive Layer size; diameter = 1 mm, height = 0.1 mm
[Changes]
-Composition of conductive adhesive layer: 1 layer (Comparative Examples 1 and 2)
-Composition of conductive adhesive; (1) Contains amino groups, (2) Contains iminodiacetic acid groups-Size of adhesive layer; Diameter of thermosetting conductive adhesive layer is the diameter of thermoplastic conductive adhesive (Thermosetting conductive adhesive layer; diameter = 1.5 mm, thermoplastic conductive adhesive layer; diameter = 1.0 mm)
(B) Manufacturing method of mounting structure which is a sample [when a thermoplastic conductive adhesive layer is disposed on the electronic component side and a thermosetting conductive adhesive layer is disposed on the substrate side (in the case of FIG. 3 )]
(1) After printing a thermoplastic conductive adhesive on the electrode of the electronic component, it is heated at a temperature of 150 ° C. for 30 minutes.
(2) Use a metal mask and screen print a thermosetting conductive adhesive on the electrodes on the substrate.
(3) After mounting the electronic component on the substrate, heat it for 30 minutes at a temperature of 150 ° C. [A thermosetting conductive adhesive layer is placed on the electronic component side, and a thermoplastic conductive adhesive on the substrate side. When placing layers (in the case of FIGS. 4 and 5)]
(1) After using a metal mask and printing a thermoplastic conductive adhesive on the electrode of the substrate 2, heating is performed at a temperature of 150 ° C. for 30 minutes.
(2) Screen printing of a thermosetting conductive adhesive on a thermoplastic conductive adhesive layer cured using a metal mask, followed by heating at 150 ° C. for 30 minutes [thermosetting In the case where only the conductive adhesive layer or the thermoplastic conductive adhesive layer is disposed (in the case of FIG. 8 or FIG. 9))
(1) Screen printing of thermosetting conductive adhesive or thermoplastic conductive adhesive on the electrode of the substrate 2 using a metal mask
(2) After mounting the electronic components, heat them for 30 minutes at a temperature of 150 ° C. As a result, it has a basic configuration and changed parts as shown in (A), and a manufacturing method as shown in (B). Reference Examples 1 to 8, Example 1 and Comparative Examples 1 and 2 which are mounting structures as manufactured samples are obtained, and each of these has specifications as shown in Table 1. Therefore, when an evaluation test as shown in (C) below was performed on each of Reference Examples 1 to 8, Example 1 and Comparative Examples 1 and 2, the test results shown in Table 2 were obtained. It was. The terms in Table 1 mean the contents of (Note 1) to (Note 3).
[0031]
[Table 1]

[0032]
(Note 1) Adhesive layer configuration; conductive adhesive layer configuration that electrically connects electronic components and the substrate; thermosetting; thermosetting conductive adhesive and thermoplastic; thermoplastic conductive adhesive (Note 2) Adhesive material; Composition of conductive adhesive ・ Amino; Use epoxy resin containing amino group as binder resin for conductive adhesive ・ Iminodiacetic acid; Contain iminodiacetic acid group as binder resin for conductive adhesive Use epoxy resin (Note 3) Adhesive layer size; conductive adhesive layer size / thermosetting>thermoplastic; thermoplastic conductive adhesive layer diameter larger than thermosetting conductive adhesive layer diameter (Thermosetting conductive adhesive layer; diameter = 1.5 mm, thermoplastic conductive adhesive layer; diameter = 1.0 mm)
(C) Evaluation test method for mounting structure which is a sample [Test 1] Removability evaluation test board for electronic components after mounting, and vacuum suction nozzle while fixing the connection part locally at a temperature of 200 ° C. The time required for the electronic component to be lifted upward using the substrate and the component to be separated from the substrate was measured. [Test 2] Substrate recyclability evaluation test The substrate after completion of Test 1 was immersed in an isopropyl alcohol solution for 60 minutes. Then, the presence or absence of conductive adhesive residue was visually evaluated. [Test 3] The reliability evaluation test board in actual use was fixed, and the electronic component was pressurized from the side using a compression tester. The force acting when the electronic component is detached from the substrate was measured.
[Table 2]

[0034]
And according to the test result shown in Table 2, the following facts are confirmed. That is, in the mounting structure according to this embodiment ( Reference Examples 1 to 8 ), the electrical connection between the electronic component 1 and the substrate 2 is performed using the thermosetting conductive adhesive layer 3 and the thermoplastic conductive adhesive layer 4. Therefore, the detachability of the electronic component 1 after mounting is improved as compared with the mounting structure (Comparative Example 1 and Comparative Example 2) according to the conventional form. Further, in the mounting structure ( Reference Example 2 ) in which the thermoplastic conductive adhesive layer 4 is disposed on the substrate 2 side, the recyclability of the substrate 2 is improved.
[0035]
Furthermore, at least one of the conductive adhesive layers 3 and 4 has a mounting structure ( Reference Example 3 to Reference Example 5 ) containing an amino group that is a functional group that easily reacts with the resin, and easily absorbs metal. Mounting structure containing iminodiacetic acid group which is a functional group ( Reference Example 6 to Reference Example 8 ), or mounting structure with improved dimensions (adhesive layer size) of conductive adhesive layers 3 and 4 If it is ( Example 1 ), it turns out that the reliability at the time of actual use is improving.
[0036]
Here, the functional group that easily reacts with the resin is an amino group, and the functional group that easily adsorbs a metal is the iminodiacetic acid group. However, the functional group that easily reacts with the resin is a carboxyl group or vinyl. Group, epoxy group, amino group, methacryl group, mercapto group, and a functional group that easily adsorbs a metal is a monocarboxyl group, a dicarboxyl group, an aminocarboxyl group, Of course, it may be at least one selected from an iminodipropionic acid group and an ethylenediaminediacetic acid group.
[0037]
Furthermore, in the above description, the electronic component 1 constituting the mounting structure is a ceramic capacitor, and the substrate 2 is a glass epoxy substrate. However, the present invention is not limited to such a configuration. The present invention can also be applied to a mounted structure including a surface mounted electronic component such as a mounted structure of a semiconductor chip and a carrier substrate, a lead component, a bare chip component, a package component, or the like. It is clear that this is possible.
[0038]
【The invention's effect】
As described above, according to the mounting structure according to the present invention, one of the two conductive adhesive layers that electrically connect the electrode of the electronic component and the electrode of the substrate is made to be a thermosetting conductive material. Since the other is a thermoplastic conductive adhesive layer, the thermosetting and thermoplastic conductive adhesive layers complement each other's weaknesses, and the advantages of both are emphasized. As a result, it is possible to repair and to obtain an effect that sufficiently high mounting reliability can be secured. According to the manufacturing method of the present invention, it is possible to easily manufacture a mounting structure that can be repaired and that can ensure high mounting reliability.
[0039]
Furthermore, according to the present invention, the effect of improving the impact resistance can be obtained as follows. In other words, the conventional mounting structure uses only a relatively hard (high elastic modulus) thermosetting adhesive, so stress concentrates on the adhesive interface when an impact such as a drop is applied, resulting in failure due to interface peeling. However, since the mounting structure according to the present invention has a plastic layer with a low Young's modulus and stress is absorbed by the plastic layer when an impact is applied, no defects occur. become.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a mounting structure according to a reference embodiment .
FIG. 2 is a cross-sectional view showing a mounting structure according to the embodiment .
FIG. 3 is a cross-sectional view showing a mounting structure according to a reference example .
FIG. 4 is a cross-sectional view showing a mounting structure according to a reference example .
FIG. 5 is a cross-sectional view showing a mounting structure according to an example.
FIG. 6 is a cross-sectional view showing a first mounting structure according to a conventional embodiment.
FIG. 7 is a cross-sectional view showing a second mounting structure according to a conventional form.
FIG. 8 is a cross-sectional view showing a mounting structure according to a comparative example.
FIG. 9 is a cross-sectional view showing a mounting structure according to a comparative example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Electronic component 2 Board | substrate 3 Thermosetting conductive adhesive layer 4 Thermoplastic conductive adhesive layer

Claims (6)

The electrode of the electronic component and the electrode of the substrate are electrically connected via the two conductive adhesive layers, and a thermosetting conductive adhesive layer is disposed on the electrode side of the electronic component. And a mounting structure in which a thermoplastic conductive adhesive layer is disposed on the electrode side of the substrate,
The thermosetting conductive adhesive layer covers the thermoplastic conductive adhesive layer and reaches the electrode of the substrate. Further, the thermosetting conductive adhesive layer and the thermoplastic The conductive adhesive layer is in direct contact with the mounting structure. The mounting structure according to claim 1 ,
At least one of a thermosetting conductive adhesive layer and a thermoplastic conductive adhesive layer contains a functional group that easily reacts with a resin. The mounting structure according to claim 2 ,
The mounting structure is characterized in that the functional group that easily reacts with the resin is at least one selected from a carboxyl group, a vinyl group, an epoxy group, an amino group, a methacryl group, and a mercapto group. The mounting structure according to claim 1 ,
At least one of a thermosetting conductive adhesive layer and a thermoplastic conductive adhesive layer contains a functional group that easily adsorbs a metal and a filler metal . The mounting structure according to claim 4 ,
The functional group that easily adsorbs a metal is at least one selected from a monocarboxyl group, a dicarboxyl group, an aminocarboxyl group, an iminodiacetic acid group, an iminodipropionic acid group, and an ethylenediaminediacetic acid group. Implementation structure to be Print and cure the thermoplastic conductive adhesive layer on the electrode of the substrate, print the thermosetting conductive adhesive layer on the thermoplastic conductive adhesive layer, then thermoset conductive A mounting structure manufacturing method for curing a thermosetting conductive adhesive layer after mounting an electrode of an electronic component on an adhesive layer ,
The thermosetting conductive adhesive layer covers the thermoplastic conductive adhesive layer and reaches the electrode of the substrate, and further, the thermosetting conductive adhesive layer and the thermoplastic conductive adhesive A method for manufacturing a mounting structure, wherein the agent layer is in direct contact .

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