JP2553491B2 - How to join electronic components - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to an electronic component joining method for adhesively joining an electronic component to an electronic component mounting portion by electrically connecting both terminals thereof.

[Technical background of the invention]

As a method of connecting electronic components such as an LSI chip and a liquid crystal display panel to an electronic component mounting portion such as a wiring board, there is a method of electrically connecting both terminals of the electronic component to the electronic component mounting portion by adhesive bonding. .

In this method, an electronic component having a plurality of terminals formed on a joint surface with the electronic component mounting portion and an electronic component mounting portion having a plurality of electronic component connecting terminals corresponding to the terminals of the electronic component are provided. An electronically conductive adhesive is generally used as the bonding material, which is bonded by a bonding material that bonds the terminals of both the electronic component and the electronic component mounting portion in a conductively connected state.

To connect electronic components using this anisotropic conductive adhesive, the anisotropic conductive adhesive is applied to an electronic component mounting portion such as a wiring board, and the electronic components are stacked and pressed to It is performed by curing the adhesive in the state.

The anisotropic conductive adhesive is a mixture of electrically conductive particles in an insulating adhesive in such a ratio that the conductive particles do not contact each other, and is made of this anisotropic conductive adhesive. Since the adhesive layer has conductivity in the thickness direction but has insulation in the surface direction (lateral direction), an anisotropic conductive adhesive is interposed on the joint surface between the electronic component and the electronic component mounting portion. When the electronic component and the electronic component mounting portion are pressed relative to each other, the terminals of the electronic component and the terminals of the electronic component mounting portion are electrically connected (electrically connected via conductive particles).

[Problems of background technology]

However, in the method of adhesively joining the electronic components with the anisotropic conductive adhesive, the electronic components can be joined only by relatively pressing the electronic component and the electronic component mounting portion to cure the adhesive. Although the electronic parts can be connected in a short time, this method does not always ensure that all the terminal parts of the electronic parts and the terminals of the electronic part mounting part are conductively connected. There was a problem that was bad.

This is because the distribution of the conductive particles of the anisotropic conductive adhesive varies irregularly.
Since the terminal width of electronic parts such as chips and liquid crystal display panels is very narrow, there is a portion where the gap between the conductive particles is larger than the terminal width in the anisotropic conductive adhesive, and the terminal is If this happens, the conductive particles are not interposed between the terminals of the electronic component and the electronic component mounting portion in this portion, and the terminals in this portion are not electrically connected.
If the mixing ratio of the conductive particles in the anisotropic conductive adhesive is increased, the distance between the conductive particles also becomes smaller, so that all the particles can be almost surely conductively connected. If the mixing ratio of the conductive particles in the conductive adhesive is increased, the conductive particles will contact each other in the part where the conductive particles are closely spaced and short-circuit adjacent terminals. Become.

[Object of the Invention]

The present invention has been made in view of the above circumstances, and an object thereof is to efficiently mount an electronic component in an electronic component mounting portion in a short time as in the case of using an anisotropic conductive adhesive. Can be joined to
It is an object of the present invention to provide a method for joining electronic components, in which each terminal of the electronic component can be surely connected to each terminal of the electronic component mounting portion without causing a defective conduction portion.

[Outline of Invention]

That is, according to the present invention, an insulating adhesive layer is formed on a base material having a release agent, conductive particles are added to the insulating adhesive layer, and terminals of both an electronic component to be joined and an electronic component mounting portion are formed. One of the terminals having a narrower width is embedded at equal intervals to prepare a bonding material, the base material is peeled from the bonding material, and the bonding material is arranged in the electronic component or the electronic component mounting portion. Overlapping on a plurality of terminals, the electronic component mounting portion or each terminal of the electronic component is superposed on the bonding material in correspondence with the terminal of the partner to be connected, and the electronic component and the electronic component mounting portion are opposed to each other. It is designed to be pressed and joined.

That is, in the present invention, the bonding material is interposed between the electronic component and the electronic component mounting portion by peeling off the base material, and the bonding material includes conductive particles in the insulating adhesive layer. Since the adhesive is embedded, the bonding material is interposed between the electronic component and the electronic component mounting portion to relatively press the electronic component and the electronic component mounting portion to form the insulating adhesive of the bonding material. Electronic components can be joined simply by curing, and therefore electronic components can be joined efficiently in a short time as in the method of adhesively joining electronic components with an anisotropic conductive adhesive. The material is not a mixture of conductive particles in the insulating adhesive in advance like an anisotropic conductive adhesive, but the conductive particles are bonded to the insulating adhesive layer formed on the base material surface. Both electronic components and electronic component mounting parts Since the width of the terminal is narrower than the width of the narrower terminal and the terminals are embedded at equal intervals, conduction is caused by uneven distribution of conductive particles as when using an anisotropic conductive adhesive. No defective portion is generated, and therefore, each terminal of the electronic component can be surely connected to each terminal of the electronic component mounting portion without causing a defective conduction portion, and the conductive particles are connected to each terminal. Since there is always one corresponding to, it is not necessary to perform alignment when superposing on a plurality of terminals arranged in the electronic component or the electronic component mounting portion.

Example of Invention

An embodiment of the present invention will be described below with reference to the drawings.

1 and 2 show cross sections of the bonding material,
In the figure, 1 is a sheet-like base material made of a flexible synthetic resin, and a release agent 2 is applied to the surface of the base material 1.
Reference numeral 3 denotes an insulating adhesive layer formed by applying an insulating adhesive to the surface of the base material 1 to a uniform thickness. The insulating adhesive layer 3 is a release agent 2 surface of the base material 1. It is formed so that it can be peeled off. The conductive particles 4, 4, ... Are a large number of conductive particles embedded in the insulating adhesive layer 3, and the conductive particles 4, 4 ,. It is buried inside. The conductive particles 4, 4, ... Are, for example, nickel particles plated with gold, solder particles, copper particles plated with gold or silver, or graphite particles. Reference numeral 5 denotes a release paper which is releasably attached to the surface of the insulating adhesive layer 3, and the release agent 6 is also applied to the surface of the release paper to which the insulating adhesive layer is attached.

FIG. 3 shows a method of manufacturing the bonding agent in the order of steps. This bonding material is manufactured as follows.

First, as shown in FIG. 3 (a), an insulating adhesive is applied to the surface of the base material 1 on which the release agent 2 has been applied to the insulating adhesive layer 3 in a uniform thickness to form the insulating adhesive. Form layer 3. The insulating adhesive layer 3 is formed of the conductive particles.
Depending on the particle size of the largest particle among 4, 4, ..., For example, when the particle size of the largest particle is 40 μ, it is applied to a thickness of about 40 to 60 μ.

Next, a mesh screen 7 is placed on the insulating adhesive layer 3 as shown in FIG. 3 (b). The mesh screen 7 is made of resin fiber such as tetron or a thin plate of stainless steel or the like having fine openings formed by etching or the like. The mesh screen 7 is one of the conductive particles 4, 4 ,. The width of the terminal (narrow width terminal) which is larger than the maximum particle diameter and has a narrower width of both terminals of the electronic component and the electronic component mounting portion that are adhesively bonded by the bonding material, and the electronic component. Of the electronic component mounting portion and the electronic component mounting portion, which have a smaller terminal spacing (narrow terminal spacing), have a large number of openings 7a, 7a, ... It is supposed to have been formed. The thickness of the mesh screen 7 is
Of the conductive particles 4, 4, ..., The particle size is approximately the same as or slightly thicker than the maximum particle size.

After this, as shown in FIG. 3 (c), the conductive particles 4, 4,
Is sprayed to a substantially uniform thickness, and is then pressed by a pressure jig such as a roller 8 as shown in FIG. 3 (d), into the openings 7a, 7a, ... Of the mesh screen 7. The conductive particles 4, 4, ... Entered are pushed into the insulating adhesive 3.
In this case, if all the particle diameters of the conductive particles 4, 4, ... Are the maximum particle diameters, one conductive particle 4, 4, ... Will enter each opening 7a, 7a ,. One conductive particle 4, 4, ... Is pressed into the insulating adhesive layer 3 at equal intervals,
Since making the particle diameters of the conductive particles 4, 4, ... Along the yield causes an increase in cost, the conductive particles 4, 4, ... Having a somewhat small diameter are also used in this embodiment. Therefore, when the conductive particles 4, 4, ... Are sprinkled on the mesh screen 7, the conductive particles 4 having the maximum diameter enter the openings 7a of the mesh screen 7 one by one and are pushed into the insulating adhesive layer 3. ,
A plurality of small-diameter conductive particles 4 enter the opening 7a of the mesh screen 7 and are pushed into the insulating adhesive layer 3, but even in that case, the conductive particles 4 pushed into the insulating adhesive layer 3,
The intervals of 4, ... Are substantially equal.

After the conductive particles 4, 4, ... Are pushed into the insulating adhesive layer 3 in this way, the scattered conductive particles 4, 4, ... Conductive particles 4, excluding conductive particles 4,4, ...
4, ... Are removed as shown in FIG. The removed conductive particles 4, 4, ... Are recovered and reused.

Next, as shown in FIG. 3 (f), the mesh screen 7 is removed from the insulating adhesive layer 3 and then, as shown in FIG. 3 (g), the insulating adhesive layer 3 is removed. , A release paper 5 coated with a release agent 6 for the insulating adhesive layer 3 on the lower surface, and pressure is applied from above with a pressure jig such as a roller 9 to insulate the conductive particles 4, 4 ,. Embedded in the adhesive layer 3.

The insulating adhesive may be a room temperature curing type,
A thermoplastic adhesive that is generally called a hot melt type, a thermosetting type, or a UV ink may be used.If a room temperature curing type adhesive or a UV ink is used as an insulating adhesive, it is conductive. The release paper 5 laminated on the surface of the insulating adhesive layer 3 at the time of embedding the particles 4, 4, ... Is left on the insulating adhesive layer 3 as it is and the insulating paper is not naturally cured by the release paper 5. When a thermoplastic adhesive or a thermosetting adhesive called hot melt type is used as the insulating adhesive, the release paper 5 is peeled off and the insulating adhesive layer 3 is protected. May be dried by hot air or infrared rays.

The bonding material is applied to the surface of the base material 1 with an insulating adhesive while the long base material 1 is fed, and the conductive particles 4, 4, ... Are equally spaced in the insulating adhesive layer 3. Are continuously manufactured by a method of embedding, and the tape-shaped bonding material is wound in a roll shape and cut to a required size according to the size of the electronic component before use.

Next, a method of connecting an electronic component such as an LSI chip or a liquid crystal display panel to the electronic component mounting portion of the wiring board by using the bonding material will be described.

In FIG. 4, 10 is a wiring board, and this wiring board
A large number of wirings 11, 11, ... Are formed on 10 faces. The wirings 11, 11, ... Are derived from the LSI chip mounting portion on the surface of the wiring board 10, and the end portions of the wirings 11, 11, ... on the LSI chip mounting portion side are the terminals 21 of the LSI chip 20. , 21, ... Corresponding to the LSI chip connection terminals 11a, 11a ,. Further, some of the wirings 11, 11, ... Of the wirings are guided to the display panel mounting portion on the side edge of the wiring board, and the end portions of the respective wirings 11, 11 ,. Each terminal 3
Display panel connection terminals 11b, 1 corresponding to 1,31, ...
It is said to be 1b, ... The LSI chip connection terminal 11
The widths of the terminals a, 11a, ... And the display panel connecting terminals 11b, 11b, ... Are respectively the widths of the terminals 21, 21, ... Of the LSI chip 20 and the widths of the terminals 31, 31 ,. It has a slightly narrow width.

When the LSI chip 20 is connected to the wiring board 10, the base material 1 is first peeled from the bonding material (if the release paper 5 is present on the surface of the insulating adhesive layer 3, the release paper 5 is also removed), The bonding material a from which the base material 1 has been peeled off is placed on the LSI chip mounting portion of the wiring board 10 as shown in FIG.
After that, the LSI chip 20 is overlaid on the bonding material a so that the terminals 21, 21, ... Of the LSI chip 20 correspond to the terminals 11a, 11a ,. Are relatively pressed to cure the insulating adhesive of the bonding material a in this state (for example, when the insulating adhesive is a thermoplastic adhesive called a hot melt type or a thermosetting type adhesive). Is
The insulating adhesive is cured by heating and pressing with a press jig or pressure roller).

When the LSI chip 20 and the wiring board 10 are relatively pressed in this manner, the terminals 21 of both the LSI chip 20 and the wiring board 10,
11a are electrically connected to each other via conductive particles 4 embedded in the insulating adhesive layer 3 of the bonding material a as shown in FIGS. 5 and 6, and the insulating adhesive is applied in this state. When cured, the LSI chip 20 and the wiring board 10 are adhesively bonded to each other by the insulating adhesive layer 3. 5 and 6, reference numeral 40 is a molding resin such as epoxy resin for molding the LSI chip mounting portion of the wiring board 10, and the molding resin 40 is applied after the LSI chip 20 is joined. Further, in FIG. 6, 22 is a base material of the LSI chip (here, N-type base material), 23 is a P-type diffusion layer, and 24 is an N-type diffusion layer. An insulating film 25 made of silicon oxide (SiO ₂ ) is formed on the main surface, and a wiring 26 made of aluminum is formed thereon. The wiring 26 is electrically connected to any of the diffusion layers at the opening provided in the insulating film 25.
The pad portion 26a formed at the lead-out end of 26 is directly used as the external circuit connecting terminal 21. Incidentally, 27 is an insulating protective film made of silicon oxide, and this protective film 27 is formed excluding the terminal 21 portion.

On the other hand, in the liquid crystal display panel 30, the terminal array portion is overlaid on the display panel mounting portion of the wiring board 10 via the joining material and joined to the wiring board 10 in the same manner as described above.

When the insulating adhesive of the bonding material is a room temperature curing adhesive or UV ink, the bonding material a is placed on the surface of the wiring substrate 10 immediately after the base material 1 and the release paper 5 are peeled from the bonding material. Instantly electronic components (LSI chip 20 and liquid crystal display panel 3
It is necessary to carry out the joining of 0), but if the insulating adhesive is a thermoplastic adhesive or a thermosetting adhesive called hot melt type, the base material 1 is peeled off from the joining material in advance. The release paper 5 may be peeled off after the bonding material is manufactured.

Then, the bonding material used in the present invention is, as described above,
Since the electrically conductive particles 4, 4, ... Are embedded in the insulating adhesive layer 3, the bonding material is interposed between the electronic component and the electronic component mounting portion such as a wiring board to form the electronic component. The electronic component can be joined by simply pressing the electronic component mounting portion relatively and curing the insulating adhesive of the joining material. Therefore, a method of adhesively joining the electronic component with the anisotropic conductive adhesive and Similarly, electronic parts can be joined efficiently in a short time, and the joining material used in the present invention is one in which conductive particles are mixed in advance in an insulating adhesive like an anisotropic conductive adhesive. However, the conductive particles 4, 4, ... Are formed in the insulating adhesive layer 3 formed on the surface of the base material 1, and the width of both terminals of the electronic component to be joined and the electronic component mounting portion is narrow. Is the width of the other terminal narrower and embedded at equal intervals? , There is no conduction failure due to uneven distribution of conductive particles as in the case of using anisotropic conductive adhesive.Therefore, each terminal of the electronic component is connected to each terminal of the electronic component mounting part. Conductive connection can be surely made without producing a defective portion, and since one conductive particle is surely associated with each terminal, it is superposed on a plurality of terminals arranged in an electronic component or an electronic component mounting portion. There is no need to perform alignment at the time.

In the above embodiment, the bonding material is used to bond the entire surface of the electronic component, but the bonding material may be configured to bond only the terminal array portion of the electronic component.

〔The invention's effect〕

According to the present invention, the electronic components can be efficiently joined in a short time as in the method of adhesively joining the electronic components with the anisotropic conductive adhesive, and the joining material used in the present invention is anisotropic. Unlike conductive adhesive, conductive particles are not mixed in advance in the insulating adhesive, but conductive particles in the insulating adhesive layer formed on the base material surface Since the width of both terminals of the component mounting portion is narrower than the width of the narrower terminal and is embedded at equal intervals, each terminal of the electronic component is connected to each terminal of the electronic component mounting portion. Conductive connection can be surely made without generating a defective conduction part, and one conductive particle corresponds to each terminal inevitably. Therefore, the conductive particles are superposed on a plurality of terminals arranged in an electronic component or an electronic component mounting portion. It is necessary to perform alignment when performing Also eliminated.

[Brief description of drawings]

The drawings show one embodiment of the present invention. FIG. 1 is a sectional view of a bonding material, FIG. 2 is an enlarged view of a part of FIG. 1, and FIG.
The figure is a cross-sectional view showing the manufacturing process of the bonding material in the order of steps, FIG. 4 is a perspective view of the wiring board and the electronic component showing the method of connecting the electronic component to the electronic component mounting portion of the wiring substrate, and FIG. 5 is the wiring substrate. FIG. 6 is a sectional view taken along the terminal arrangement line in a state where the LSI chips are joined, and FIG. 6 is an enlarged sectional view taken along the line AA in FIG. 1 ... Substrate, 2 ... Release agent, 3 ... Insulating adhesive layer, 4
…… Conductive particles, 5 …… Release paper, 6 …… Release agent, 7 ……
Mesh screen, 7a ... Opening, a ... Bonding material removed, 10 ... Wiring board, 11 ... Wiring, 11a ... LSI connection terminal, 11b ... Display panel connection terminal, 20 ... LSI chip, 21 …… terminal, 30 …… liquid crystal display panel, 31 …… terminal, 40 …… mold resin.

Front page continued (72) Inventor Hisashi Masaki 3-2-1 Sakaemachi, Hamura-cho, Nishitama-gun, Tokyo Casio Computer Co., Ltd., Hamura Technical Center (72) Inventor Yoshio Akita 3-Sakae-cho, Hamura-cho, Nishitama-gun, Tokyo No. 2-1 Casio Computer Co., Ltd. in Hamura Technology Center (72) Inventor Yoshinori Atsumi 3-2-1 Sakaemachi, Hamura-cho, Nishitama-gun, Tokyo Casio Computer Co., Ltd. in Hamura Technology Center (72) Inventor Tamaki Toshiharu 3-2-1, Sakaemachi, Hamura-cho, Nishitama-gun, Tokyo Casio Computer Co., Ltd., within Hamura Technology Center (56) References JP-A-51-21192 (JP, A), JP-A-55-142535 (JP, U)

Claims (1)

(57) [Claims] 1. An insulating adhesive layer is formed on a base material having a release agent, and conductive particles are added to the insulating adhesive layer for the terminals of both the electronic component to be joined and the electronic component mounting portion. A plurality of terminals arranged in the electronic component or the electronic component mounting portion are prepared by embedding a bonding material that is narrower than one of the terminals whose width is narrower and embedded at equal intervals. Of the electronic component mounting portion or each terminal of the electronic component is overlapped on the bonding material corresponding to the other terminal to be connected, and the electronic component and the electronic component mounting portion are relatively disposed. A method for joining electronic components, which comprises pressing and joining the components.