JPS61187394A - Joint material for connection of electronic component - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (Technical Field of the Invention) The present invention relates to a bonding material for connecting an electronic component to an electronic component mounting part by adhesively bonding both terminals of the electronic component to a part thereof in a conductive connection. be.

[Technical background of the invention]

Electronic components such as LSI chips and liquid crystal display panels are attached to electronic components such as wiring boards, and both terminals are electrically connected to the component by adhesive bonding. There is.

This method consists of an electronic component with a plurality of terminals formed on the joint surface with an electronic component mounting section, and an electronic component mounting section with a plurality of electronic component connection terminals formed thereon that correspond to each terminal of the electronic component. , this electronic component is attached by adhesively bonding the electronic component with a bonding material that is bonded with the terminals of both parts electrically connected, and an anisotropic conductive adhesive is generally used as the bonding material. There is.

To connect electronic components using this anisotropic conductive adhesive, apply the anisotropic conductive adhesive to the area where the electronic components such as wiring boards are attached, stack the electronic components on top of it, and apply pressure. This is done by curing the adhesive under the conditions.

The anisotropically conductive adhesive is an insulating adhesive mixed with conductive particles in a proportion such that the conductive particles do not come into contact with each other. The adhesive layer exhibits electrical conductivity in the thickness direction but insulating properties in the plane direction (lateral direction), so when attaching electronic components, an anisotropically conductive adhesive is interposed between the two parts. When you press the electronic component and the electronic component mounting part relatively,
Each terminal of the electronic component and each terminal of the electronic component mounting section are electrically connected (conductively connected via conductive particles).

[Problems with background technology]

However, the method of adhesively bonding electronic components using the above-mentioned anisotropic conductive adhesive is such that the electronic components can be bonded by simply pressing the electronic components and the electronic component mounting section relatively to each other and curing the adhesive. However, with this method, each terminal of the electronic component and each terminal of the electronic component mounting section are not necessarily connected for conduction. Therefore, there was a problem of poor reliability.

This is because the distribution of conductive particles in the anisotropic conductive adhesive varies irregularly, whereas LSI
Since the terminal areas of electronic components such as chips and liquid crystal display panels are very narrow, there are areas in the anisotropically conductive adhesive where the spacing between the conductive particles is wider than the terminal area, and the terminals are placed at these areas. Coincidentally, in this part, conductive particles are not interposed between the terminals of the electronic component and the electronic component mounting part, so that the terminals of this part are not electrically connected.

Note that if the mixing ratio of conductive particles in the anisotropic conductive adhesive is increased, the spacing between the conductive particles will also become smaller, so all terminals can be connected almost reliably. However, if the mixing ratio of conductive particles in the conductive adhesive is increased, the conductive particles will come into contact with each other in areas where the conductive particles are closely spaced, causing short-circuits between adjacent terminals. Become.

[Purpose of the invention]

This invention was made in view of the above-mentioned circumstances, and its purpose is to efficiently attach electronic components in a short period of time, similar to when using an anisotropic conductive adhesive. Provided is a bonding material for connecting electronic components that can be bonded to the electronic component, and also allows each terminal of the electronic component to be reliably connected to each terminal of the electronic component without causing a conductive defective part. It's about doing.

(Summary of the Invention) That is, the present invention forms an insulating adhesive layer on the surface of a sheet-like base material so that it can be peeled off from the base material, and in this insulating adhesive layer, a large number of openings are formed. The bonding material of the present invention has an insulating mesh screen formed at equal intervals and conductive particles inserted into each opening of the mesh screen. It is used in

In other words, the bonding material of the present invention is interposed between the electronic component and the electronic component mounting section by peeling off the base material, and this bonding material includes conductive particles in the insulating adhesive layer. Since it is embedded, this bonding material is interposed between the electronic component and the electronic component mounting section, and the electronic component and the electronic component mounting section are pressed relative to each other, and the insulating adhesive of the bonding material is applied. Electronic components can be joined by simply curing 1. Therefore, electronic parts can be joined efficiently in a short time, similar to the method of adhesively joining electronic parts with an anisotropic conductive adhesive. Rather than mixing conductive particles into an insulating adhesive in advance, conductive particles are embedded together with an insulating mesh screen into an insulating adhesive layer formed on the base material surface, and the mesh screen conducts electricity. Since the spacing of the conductive particles is regulated to be equal, there is no possibility of poor conductivity due to variations in the distribution of the conductive particles, unlike when using anisotropic conductive adhesives. It is possible to reliably conductively connect each terminal of the electronic component mounting section to each terminal of the electronic component mounting section without causing any conductive defects.

[Embodiments of the invention]

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

Figures 1 and 2 show cross sections of the bonding material. In the figures, 1 is a sheet-like base material made of flexible synthetic resin, and the surface of this base material 1 is coated with a release agent 2. It is coated. 3
is an insulating adhesive layer formed by applying an insulating adhesive to a uniform thickness on the surface of the base material 1. Formed to be removable.

4.4. ... is a large number of conductive particles embedded in the insulating adhesive layer 3, and 5 is the conductive particle 4,4°...
This is also an insulating mesh screen embedded in the insulating adhesive layer 3. This mesh screen 5 is
A large number of openings 5a having a predetermined size.

5a, . . . are formed at regular intervals at predetermined intervals, and conductive particles 4.4. ... are inserted into each opening 5a, 5a, ... of the mesh screen 5, and are buried in the insulating adhesive layer 3 at equal intervals with the intervals regulated by the mesh screen 5. . Note that this conductive particle 4.4. Examples include nickel particles plated with gold, solder particles, copper particles plated with gold or silver, and graphite particles. Also,
Reference numeral 6 denotes a release paper that is releasably adhered to the surface of the insulating adhesive layer 3, and a release agent 7 is also applied to the surface of the release paper 6 to which the insulating adhesive layer is adhered.

FIG. 3 shows the method for manufacturing the bonding material in the order of steps, and the bonding material is manufactured as follows.

First, as shown in FIG. 3(a), an insulating adhesive is applied to a uniform thickness on the surface of the base material 1 coated with the release agent 2 for the insulating adhesive layer 3. Form layer 3. Note that this insulating adhesive layer 3 has the conductive particles 4
,4. For example, if the maximum diameter particle is 40μ, the coating is applied to a thickness of about 40 to 60μ, depending on the diameter of the largest particle.

Next, a mesh screen 5 is placed on this insulating adhesive layer 3 as shown in FIG. 3(b).

This mesh screen 5 is made of a resin fiber network such as Tetoron, and is insulating and elastic.・
The terminal with the narrower width of both terminals (narrow width terminal), which is larger than the particle size of the largest particle among the electronic components and which are adhesively bonded with a bonding material and where the electronic components are mounted. A large number of openings 5a, 5a, . They are said to be formed at equal intervals smaller than the width. Note that the thickness of this mesh screen 5 is determined by the thickness of the conductive particles 4, 4. The thickness is approximately the same as the diameter of the largest particle among...

After this, as shown in FIG. 3(C), conductive particles 4, 4 are applied over the entire surface of the mesh screen 5.
．． ... to a substantially uniform thickness, and then pressurized from above with a pressure jig such as a roller 8 as shown in FIG. 3(d) to form each opening 5a, 5a of the mesh screen 5.
, . . . conductive particles 4, 4. ... is pushed into the insulating adhesive layer 3. In this case, conductive particles 4.4. If all the particle sizes of ... are the maximum particle size, one conductive particle 4゜4, ... enters each opening 5a, 5a, ... of the mesh screen 5, so that insulating adhesive is formed. One conductive particle 4,4.・
... are pushed in, but the conductive particles 4, 4 . Since making the particle diameters of .
．． ...is also used. Therefore, conductive particles 4, 4 . . . , the conductive particles 4 with the largest diameter are distributed through the openings 5a of the mesh screen 5.
A plurality of small-diameter conductive particles 4 enter the openings 5a of the mesh screen 5 and are pushed into the insulating adhesive layer 3. However, the conductive particles 4 pushed into the insulating adhesive layer 3
,4. ... are substantially equal intervals.

In this way, conductive particles 4°4, .
After pushing ..., the conductive particles scattered 4゜4, ...
The conductive particles 4, 4, .・
Conductive particles excluding 4, 4. ... is removed as shown in FIG. 3(e). Note that the removed conductive particles 4.4. ...will be collected and reused.

Next, as shown in FIG. 3(f), a release agent 7 for the insulating adhesive layer 3 is placed on the lower surface of the mesh screen 5.
The release paper 6 coated with Particles 4.4. ... is embedded in the insulating adhesive layer 3.

The insulating adhesive may be a room temperature curing type, a thermoplastic adhesive generally called a true melt type, a thermosetting type, or a UV ink. When using a room temperature curing adhesive or UV ink as conductive particles 4, 4. When embedding..., the release paper 6 layered on the surface of the insulating adhesive 113 is left as it is on the insulating adhesive layer 3.
When using a hot-melt type thermoplastic adhesive or thermosetting adhesive as the insulating adhesive, the release paper 6 should be protected from natural hardening. After peeling off, the insulating adhesive layer 3 may be dried using hot air, infrared rays, or the like.

Further, the bonding material has an insulating adhesive layer 3 on a long base material 1.
A mesh screen 5 and conductive particles 4, 4 . are formed in this insulating adhesive layer 3. . . . is manufactured continuously by embedding the tape, and this tape-like bonding material is wound into a roll and cut into necessary dimensions depending on the size of the electronic component.

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 using the bonding material will be described.

In FIG. 4, 10 is a wiring board, and on the surface of this wiring board 10 there are many wirings 11. It, . . . are formed. Each wiring 11.11. ...is wiring board 1
The LSI chip mounting on the 0th surface is derived from the section, and each wiring 11.11. The end of the LSI chip mounting section is connected to each terminal 21, 21, . . . of the LSI chip 20. ...and the corresponding 181 chip connection terminals 1fa, 1
1a.

It is said that... Further, some of the wirings ii, it, .・・・
The ends of the terminals 31, 31, .
. . . and corresponding display panel connection terminals 11b.
, 11b,... Note that the LSI
The widths of the chip connection terminals 11a, 11a, . . . and the display panel connection terminals 11b, 11b, .
The width of ... and each terminal 31.3 of the liquid crystal display panel 30
1. The width is said to be slightly narrower than the width of...

When connecting the LSI chip 20 to the wiring board 10, first peel off the base material 1 from the bonding material, and if there is a release paper 6 on the surface of the insulating adhesive layer 3, also peel off this release paper 6), 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 this, the LSI chip 20 is placed on the bonding material a.
to its respective terminals 21, 21. ... to each terminal 11a, lla on the 10th side of the wiring board.

..., and press the LSI chip 20 and the wiring board 10 relatively to each other, and in this state, cure the insulating adhesive of the bonding material a (for example, if the insulating adhesive is a hot melt type If the adhesive is a so-called thermoplastic adhesive or thermosetting adhesive, heat and press it with a press jig or pressure roller to harden the insulating adhesive.

When the LSI chip 20 and the wiring board 10 are pressed relative to each other in this way, the elastic mesh screen 5 is compressed by this pressing force, and the LSI chip 20 and the wiring board 10 are pressed together.
Both terminals 21 and 116 are connected to the fifth terminal via conductive particles 4 embedded in the insulating adhesive layer 3 of the bonding material a.
A conductive connection is made as shown in FIG. Furthermore, when the insulating adhesive is cured in this state, the LSI chip 20
and wiring board 1 are adhesively bonded to each other by an insulating adhesive layer 3. In addition, in Figures 5 and 6, 40
The LSI chip mounting portion of the wiring board 10 is molded with a molding resin such as epoxy resin, and this molding resin 40 is applied after the LSI chip 20 is bonded. In addition, in FIG. 6, 22 is a base material of an LSI chip (in this case, an N-type base material), 23 is a P-type diffusion layer, and 24 is an N-type diffusion layer, and the chip on which these diffusion layers 23 and 24 are formed. An insulator 112 made of silicon oxide (SiO2) is provided on the main surface.
5 is formed, and a wiring 2 made of aluminum is formed on it.
6 is formed. This wiring 26 is connected to the insulating film 25.
The pad portion 2 is electrically connected to one of the diffusion layers at the opening provided in the wiring 26, and the pad portion 2 formed at the lead-out end of the wiring
6a is used as an external circuit connection terminal 21 as it is.

Note that 27 is an insulating protective film made of silicon oxide,
This protective film 27 is formed except for the terminal 21 portion.

On the other hand, the liquid crystal display panel 30 is bonded to the wiring board 10 in the same manner as described above, with its terminal arrangement portion overlapping the display panel mounting portion of the wiring board 10 via the bonding material.

When the insulating adhesive of the bonding material is a room temperature curing adhesive or U ink, the bonding material a is placed on the wiring board 10 immediately after peeling off the base material 1 and release paper 6 from the bonding material. It is necessary to bond electronic components (LSI chip 20 and liquid crystal display panel 30) immediately after placing them, but the insulating adhesive is a thermoplastic adhesive called a hot-melt adhesive or a thermosetting adhesive. In this case, the base material 1 may be peeled off from the bonding material in advance (the release paper 6 is peeled off after the bonding material is manufactured).

As described above, the bonding material of this embodiment has conductive particles 4, 4, and 4 in the insulating adhesive layer 3. ... is embedded, so when installing electronic components such as electronic components and wiring boards, this bonding material is interposed between electronic components and electronic components such as wiring boards, and when installing electronic components, the components are pressed relative to each other. Electronic components can be joined simply by curing the insulating adhesive used as the joining material. Therefore, electronic components can be joined efficiently in a short time, similar to the method of adhesively joining electronic components with anisotropic conductive adhesive. Moreover, this bonding material is not an insulating adhesive mixed with conductive particles in advance like an anisotropic conductive adhesive, but an insulating adhesive formed on one surface of the base material. In layer 3 a number of openings 5a.

5a, . . . formed at equal intervals, and each opening 5a of this mesh screen 5.
, 5a, . . . by embedding the conductive particles 4, 4° . . .
Conductive particles 4, 4. Since the intervals between the Each terminal of the component can be reliably electrically connected to each terminal of the electronic component mounting section without causing any electrical continuity defects.

In the above embodiment, the mesh screen 5 is elastic, but the thickness of the mesh screen 5 is determined by the conductive particles 4, 4. It is not necessarily necessary to make the mesh screen 5 elastic as long as the particle size is made to be a certain degree thinner than the particle size of the conductive particles 4, 4. ... is the opening 5 of the mesh screen 5, as shown in FIG.
A, 5a, . . . may be inserted in multiple stages. Also,
In the above embodiment, the bonding material is used to adhesively bond the entire surface of the electronic component, but the bonding material may be shaped to adhesively bond only the terminal array portion of the electronic component.

〔Effect of the invention〕

According to the bonding agent of the present invention, electronic components can be bonded efficiently in a short time similar to the method of bonding electronic components using an anisotropic conductive adhesive. Unlike conductive adhesives, conductive particles are not mixed into an insulating adhesive beforehand, but a mesh screen and conductive particles are embedded in an insulating adhesive layer formed on the base material surface. Since the distance between the magnetic particles is regulated at equal intervals using a mesh screen, each terminal of the electronic component can be reliably connected to each terminal of the electronic component mounting section without causing any conductive defects. .

[Brief explanation of the drawing]

Figures 1 to 6 show an embodiment of this invention.
Fig. 1 is a sectional view of the bonding material, Fig. 2 is an enlarged view of a portion of Fig. 1, Fig. 3 is a sectional view showing the manufacturing process of the bonding material in order of process, and Fig. 4 is a diagram showing how to attach electronic components to a wiring board. FIG. 5 is a cross-sectional view taken along the terminal arrangement line with the LSI chip bonded to the wiring board, and FIG. 6 is A of FIG. 5. - It is an enlarged sectional view along the A line. FIG. 7 is an enlarged sectional view of a portion of a bonding material showing another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Base material, 2... Release agent, 3... Insulating adhesive layer, 4... Conductive particles, 5... Mesh screen, 5a... Opening, 6... Release paper, 7... Release agent,
a... Bonding material from which the base material has been peeled off, 10... Wiring board,
11...Wiring, 11a...LSI connection terminal, Il
b... Display panel connection terminal, 20... LSI chip, 21... Terminal, 30... Liquid crystal display panel, 31
...Terminal, 40...Mold resin. Applicant's agent Patent attorney Takehiko Suzue Figure 1 (↑ Shinkai, Neo TM page B) Figure 2 (No. 111!l Issone Sen Kodai IXI) Figure 3 (Sai?l!rIF11) Il" i engineering fiT21) 4
4 l ] Figure 4

Claims (1)

[Claims] An electronic component having a plurality of terminals formed on a joint surface with an electronic component mounting portion is electrically connected to the electronic component mounting portion having a plurality of electronic component connection terminals formed thereon corresponding to each terminal of the electronic component. A bonding material for connecting and adhesively bonding, in which an insulating adhesive layer is formed on the surface of a sheet-like base material so that it can be peeled off from the base material, and in this insulating adhesive layer, A bonding material for connecting electronic components, which is formed by embedding an insulating mesh screen in which a large number of openings are formed at equal intervals, and conductive particles inserted into each opening of the mesh screen.