JP2001284780A - Mounting component and mounting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mounting method in which a chip component is mounted surely on a board by using a conductive adhesive whose bonding strength is insufficient. SOLUTION: Electrodes 2 of the component 1 are bonded to lands 4 of the board 3 via the conductive adhesive C whose bonding strength is comparatively weak. The body part 1a of the component 1 is bonded to the non-land part of the board 3 via an insulating adhesive N whose bonding strength is comparatively strong. The hardening temperature of the insulating adhesive N is selected to be lower than that of the conductive adhesive C. The hardening shrinkage percentage of the insulating adhesive is selected to be higher than that of the conductive adhesive. Instead of a thermosetting adhesive, a photocuring adhesive is used as the insulating adhesive N whose bonding strength is comparatively strong.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting component and a mounting method for mounting a chip component on a substrate without using solder, and more particularly to a component mounting structure and a component mounting method using a conductive adhesive.

[0002]

2. Description of the Related Art In recent years, due to environmental problems, it has been desired to mount chip components on a substrate without using solder.
Conductive adhesives and insulating adhesives are known as mounting materials in place of solder.

[0003]

However, the conductive adhesive has the advantage that it can be interposed between the electrode on the chip component side and the land on the substrate side, but has insufficient bonding strength, and therefore has a poor connection strength. There are disadvantages that the resistance value varies and changes with time. Here, in order to lower the connection resistance value, a method of heating and curing the thermosetting conductive adhesive between the electrode and the land while applying pressure is conceivable. There is a problem that the process becomes complicated.

[0004] In order to solve this problem of the conductive adhesive, for example, Japanese Patent Application Laid-Open No. 9-36526 discloses a method in which an electrode on a chip component and a land on a substrate are insulated while being in contact with each other. A method has been proposed in which the bonding between the body of the chip component and the substrate surface is similarly performed with an insulating adhesive, while the bonding is performed using an insulating adhesive. However, according to this method, the contact between the electrode on the chip component side and the land on the substrate side is bonded by an insulating adhesive while being in contact therewith. Therefore, in the case of a component having four or more electrodes (for example, QFP), There is a problem that it is difficult to bring all the electrodes into uniform contact during mounting.

In view of the above problems, an object of the present invention is to provide a mounting component and a mounting method capable of reliably mounting a chip component on a substrate using a conductive adhesive having insufficient bonding strength. I do.

[0006]

According to the present invention, in order to achieve the above object, a mounted component has a conductive adhesive having a relatively low bonding strength and an insulating adhesive having a relatively high bonding strength. The electrode of the component and the land of the substrate are connected via the conductive adhesive having relatively low strength, and the body portion of the component and the non-land portion of the substrate are connected via the insulating adhesive having relatively high bonding strength. It is intended to be combined. Also,
An insulating adhesive whose curing temperature is lower than that of the conductive adhesive is selected, and an insulating adhesive whose curing shrinkage is higher than that of the conductive adhesive is selected.

That is, according to the present invention, there is provided a conductive adhesive having a relatively low bonding strength and an insulating adhesive having a relatively high bonding strength, and the conductive adhesive having a relatively low bonding strength is provided through the conductive adhesive. While connecting the electrode of the component and the land of the board,
There is provided a mounted component in which a body portion of the component and a non-land portion of the substrate are connected via the insulating adhesive having a relatively high bonding strength.

[0008] In order to achieve the above object, the present invention provides:
In addition to connecting the electrode of the component and the land of the board via a conductive adhesive with a relatively low bonding strength, the body of the component and the board via a light-curing insulating adhesive with a relatively high bonding strength The non-land portions are connected. Further, an insulating adhesive having a higher curing shrinkage than that of the conductive adhesive is selected.

That is, according to the present invention, the electrode of the component and the land of the substrate are connected via the conductive adhesive having a relatively low bonding strength, and the photo-curing insulating adhesive having the relatively high bonding strength is used. Thus, there is provided a mounted component in which a body portion of the component and a non-land portion of the substrate are joined.

According to the present invention, the electrode of the component is connected to the land of the substrate via the conductive adhesive having a relatively low bonding strength, and the photo-curable insulating adhesive having the relatively high bonding strength is bonded. And mounting the conductive adhesive on the land of the substrate and applying the insulating adhesive to the non-land portion from above. A step (1) of applying so as to protrude from the body, and after the step (1), a step of positioning and placing the electrode and the body of the component on the conductive adhesive and the insulating adhesive, respectively ( 2)
After the step (2), a step (3) of irradiating the insulating adhesive protruding from the body part with light from above to cure the same, and after the step (3), the insulating adhesive is transported in a tunnel furnace. Curing the conductive adhesive (4) is provided.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing a first embodiment of a mounting component and a mounting process according to the present invention, and FIG.
It is explanatory drawing which shows the temperature change in a tunnel furnace and the hardening time of conductive adhesive C of this example, and insulating adhesive N.

In the chip part 1 shown in FIG. 1, for example, two electrodes 2 such as a resistor and a capacitor are formed at both ends of a body part 1a. When the chip part 1 is mounted on a substrate 3, A land 4 is formed on the substrate 3 in advance so as to face the electrode 2. And in the present invention,
The electrode 2 and the land 4 are joined together with a thermosetting conductive adhesive C interposed between the electrode 2 and the land 4, and the same thermosetting type adhesive is provided between the body portion 1 a and the non-land portion on the substrate 3. Bonding is performed via the insulating adhesive N.

Here, in general, the properties of the insulating adhesive N are as follows: the bonding strength is higher (N>C); the curing temperature is lower (N <C); High cure shrinkage (N> C). The conductive adhesive C
Is composed of, for example, about 85% by weight of a silver filler and the remaining weight% of an epoxy resin or an acrylic resin. The curing temperature is 150 ° for the conductive adhesive C.
C and the insulating adhesive N of about 120 ° C. are selected. The curing shrinkage ratio of the conductive adhesive C is about 8%,
A material having an insulating adhesive N larger than that is selected.

In the mounting process of the present invention, (1) FIG.
As shown in (a) and (b), a conductive adhesive C and an insulating adhesive N are applied to the lands 4 on the substrate 3 and the non-land portions, respectively. (2) Then, FIG. As shown in c), the electrode 2 of the component 1 and the body portion 1a are respectively positioned and mounted on the applied conductive adhesive C and insulating adhesive N by the mounter. (3) Then, in this state, By passing the substrate 3 through a tunnel furnace, the conductive adhesive C and the insulating adhesive N are cured as shown in FIG. 1D, and the conductive adhesive C is applied between the electrode 2 and the land 4 respectively. And an insulating adhesive N between the body portion 1a and the non-land portion.
Via

FIG. 2 shows a change in temperature of the conductive adhesive C and the insulating adhesive N when passing through a tunnel furnace. When the furnace enters the tunnel furnace, it is gradually heated.
With the lapse of time, the temperature T of the conductive adhesive C and the insulating adhesive N gradually increases, but since the curing temperature of the insulating adhesive N is lower than the conductive adhesive C, the insulating adhesive N becomes conductive adhesive. The curing starts before the agent C. Further, since the curing shrinkage of the insulating adhesive N is higher than that of the conductive adhesive C, FIG.
The conductive adhesive C having a low curing shrinkage is compressed by the electrode 2 and the land 4 as shown by the arrow in FIG. For this reason,
The connection resistance of the conductive adhesive C is lower than that in a non-compressed state in which the conductive adhesive C is simply applied. Further, when the outside is approached to the exit of the tunnel furnace, the temperatures of the conductive adhesive C and the insulating adhesive N gradually decrease to room temperature. Since it is stronger than the agent C, the electrode 2 and the land 4 can be securely connected even if the bonding strength of the conductive adhesive C is weak.

Next, the second part of the mounting component and mounting method of the present invention will be described.
An embodiment will be described. A photo-curing type is used as the insulating adhesive N. Further, a material having a bonding strength of the insulating adhesive N higher than that of the conductive adhesive C and a curing shrinkage of the insulating adhesive N higher than that of the conductive adhesive C is selected. Then, as shown in FIG. 3, when applying the insulating adhesive N,
The coating is performed so as to protrude from the body portion 1a when viewed from above, that is, when ultraviolet rays are irradiated from above.

In the curing step, (1) FIG.
(A) As shown in (b), a conductive adhesive C and an insulating adhesive N are applied on the lands 4 on the substrate 3 and on the non-land portions, respectively. As shown in FIG. 1 (c), the applied conductive adhesive C and insulating adhesive N
The electrode 2 of the component 1 and the body part 1a are respectively positioned on and mounted on a mounter. (2-2) Then, the ultraviolet ray is irradiated onto the photo-curing insulating adhesive N from above before being transported into the tunnel furnace. To cure the photo-curing insulating adhesive N first, and to form an insulating adhesive N between the body portion 1a and the non-land portion.
(3) Then, by passing the substrate 3 in this state through a tunnel furnace, the conductive adhesive C is cured as shown in FIG. Are connected via a conductive adhesive C.

Even if light is applied only to the portion of the insulating adhesive N which protrudes from the body portion 1a, the irradiated portion first undergoes photopolymerization and starts to cure, and then the portion which is not irradiated is also irradiated with the light. Photopolymerization and curing in response do not result in insufficient bonding strength. Even if the photocuring is insufficient, the insulating adhesive N is completely cured when the conductive adhesive C is thermally cured.

[0019]

As described above, according to the present invention, in addition to bonding the electrode of the component and the land of the substrate via the conductive adhesive having a relatively low bonding strength, the insulating material having a relatively high bonding strength is used. The body part of the component and the non-land portion of the board are connected via a conductive adhesive, so that even if a conductive adhesive with insufficient bonding strength is used, the chip component can be securely mounted on the board. it can. According to the present invention, in addition to bonding the electrode of the component and the land of the substrate via a conductive adhesive having a relatively low bonding strength, a light-curing insulating adhesive having a relatively high bonding strength is used. Since the body portion of the component and the non-land portion of the substrate are joined together, the chip component can be reliably mounted on the substrate even if a conductive adhesive having insufficient bonding strength is used.

[Brief description of the drawings]

FIG. 1A is a configuration diagram showing one step in a first embodiment of a component mounting structure and a component mounting step according to the present invention. (B) It is a block diagram which shows the other process in 1st Embodiment of the component mounting structure and component mounting process which concern on this invention. (C) It is a block diagram which shows another process in 1st Embodiment of the component mounting structure and component mounting process which concern on this invention. (D) It is a block diagram which shows another process in 1st Embodiment of the component mounting structure and component mounting process which concern on this invention.

FIG. 2 is an explanatory diagram showing a temperature change and a curing time of a conductive adhesive C and an insulating adhesive N in FIG. 1 in a tunnel furnace.

FIG. 3 is a configuration diagram illustrating a component mounting structure according to a second embodiment of the component mounting structure and the component mounting process according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Component 1a Body part 2 Electrode 3 Substrate 4 Land C Conductive adhesive N Insulating adhesive

Continued on the front page (72) Inventor Riki Mitani 1006 Kazuma Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. F term (reference) 5E319 AA03 AA07 AB05 CD15 5E336 AA04 BB01 CC31 DD22 DD39 EE07 EE08 EE17 GG16

Claims (5)

[Claims] 1. An electrode for a component and a substrate via a conductive adhesive having a relatively low bonding strength and an insulating adhesive having a relatively high bonding strength. And a body part of the component and a non-land portion of the substrate are connected via the insulating adhesive having a relatively high bonding strength. 2. The mounting component according to claim 1, wherein the curing temperature of the insulating adhesive is lower than that of the conductive adhesive. 3. An electrode of a component and a land of a substrate are connected via a conductive adhesive having a relatively low bonding strength, and a body portion of the component is connected via a photocurable insulating adhesive having a relatively high bonding strength. A mounting component that combines the board and the non-land part of the board. 4. The insulating adhesive according to claim 1, wherein the curing shrinkage of the insulating adhesive is higher than that of the conductive adhesive.
The mounting component according to any one of the above. 5. An electrode of a component and a land of a substrate are connected via a conductive adhesive having a relatively low bonding strength, and a body portion of the component is connected via a photo-curing insulating adhesive having a relatively high bonding strength. And a method of mounting a component that couples a non-land portion of a substrate, wherein the conductive adhesive is applied to a land of the substrate, and the insulating adhesive is applied to the non-land portion from a body portion when viewed from above. A step (1) of applying so as to protrude, and after the step (1), a step (2) of positioning and placing an electrode and a body part of the component on a conductive adhesive and an insulating adhesive, respectively. After the step (2), a step (3) of irradiating the insulating adhesive protruding from the body portion with light from above to cure the adhesive, and after the step (3), transporting the inside of the tunnel furnace to the conductive adhesive. The adhesive cures -Up (4) and the mounting method of the component having.