JPH0413789A - Conductive adhesive film and production thereof - Google Patents

Abstract

PURPOSE:To form the subject conductive adhesive film useful for connection of a high definition LCD panel by arranging plural prism conductors in a zigzag way at equal distances in the direction of a ribbon and sandwiching a hot melt adhesive between the above-mentioned conductors and then film forming. CONSTITUTION:A conductive layer is formed on a release film 4 through a release layer 5 and laser beam scribing crossing the longitudinal direction of the film at angle is carried out to leave plural prism conductors 2 arranged in a zigzag way at equal distances in the above-mentioned direction. The above- mentioned surface is then coated with a hot melt adhesive 3 to sandwich the hot melt adhesive 3 between the prism conductors 2. Film formation is carried out, thus giving the objective conductive adhesive film 1 in a ribbon shape.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is an adhesive type for electrically connecting a liquid crystal display device (hereinafter referred to as an LCD panel) to a flexible flat cable (hereinafter referred to as FFC), a chip-on film, etc. The present invention relates to a conductive film, and particularly to an adhesive conductive film useful for connecting high-definition LCD panels with an electrode pitch of about 7 cm (0.1), and a method for manufacturing the same.

[Conventional technology]

Conventionally, in the monochrome mode transmissive LCD panel used in word processors, personal computers, etc., the LCD panel and the IC-mounted printed circuit board (hereinafter referred to as PC board) are arranged 10 to 25 meters apart via a backlight module. Therefore, both terminal electrodes are connected by FFC and an adhesive conductive film.

In addition, since the chip-on-film uses tape, automation, and bonding to connect the IC thousand knob electrodes, T
Although it is called AB, the connection between the LCD panel and chip-on-film (hereinafter referred to as TAB) is also made directly using an adhesive conductive film.

For example, LCD panels used in word processors, personal computers, etc. have a diagonal screen size of approximately 10 inches (152.4
3.2m), and the number of pixels is 400 in the current monochrome mode.
X640. Pixel pinch (#terminal electrode pinch) 0.30~
0.35m is used, but in multi-color mode or full-color mode LCD baffles, the pixel resolution has become even higher, and the number of horizontal pixels is 1000 to 150.
0, pixel pinch (#terminal electrode pitch) 0.10 to 0.1
5m is required.

[Problem to be solved by the invention]

However, the conventional adhesive conductive film for connecting this LCD panel and FFC or TAB uses a film formed by dispersing conductive particles in a hot-melt adhesive. The type conductive film is styrene-butadiene-
A hot melt adhesive consisting of a thermoplastic resin such as a styrene copolymer, a tackifier, a latent curing agent, an anti-aging agent, etc.
Approximately spherical metal particles, gold-plated resin particles, etc. with a diameter of 10 to 30 μm are dispersed onto a release film to a thickness of 20 to 3 μm.
A film was formed to a thickness of 0 μm to form a ribbon with a width of 2 to 3 N, the release film was peeled off, and the film was heated at 130-190°C for 10-30'.
Although it is used by heat sealing under the conditions of c, the conductive path is narrowed because the conductive particles and the electrode are in point contact, and the electrical contact [81J] is poor, and the dispersion state of the R conductive particles is arbitrary. Therefore, if the connected electrodes have a low pitch, agglomerates of several particles may cause leakage defects between adjacent electrodes, and there may be no particles between opposing electrodes, resulting in open defects. There are drawbacks such as large diameter particles between other electrodes interfering with the connection between the electrodes and causing open defects.
In addition, this conventional adhesive conductive film has a pinch of 0.2 for the connected electrode.
m is the limit, and there is a problem in connection for use with color LCD panels, etc., which require a high definition pixel pitch (it pitch of 0.1 to 0.15 m5).

The present invention aims to accurately eliminate these conventional drawbacks, and greatly improves the reliability of electrical contact without causing leakage defects or open defects between adjacent electrodes.In addition, the pixels can be made extremely high-definition, and color LCD The object of the present invention is to provide an adhesive conductive film that enables connection to a panel, etc., and an effective manufacturing method thereof.

[Means to solve the problem]

The present invention is a ribbon-shaped adhesive conductive film in which a plurality of columnar conductors arranged perpendicular to the film surface are arranged at equal intervals in a staggered manner in the ribbon direction, and the conductors arranged in the same direction in the ribbon direction are This is an adhesive conductive film characterized in that the columnar conductors are arranged at the center of the pitch between adjacent conductor arrays, and a hot-melt adhesive is filled between the columnar conductors.

Furthermore, in order to obtain an adhesive conductive film according to the present invention, a conductive layer is formed on a release film via a release layer, and then laser beam scribing is performed that intersects the film flow direction at a fixed angle. After leaving a plurality of columnar conductors arranged at equal intervals in a staggered manner in the direction, the surface is coated with a hot-melt adhesive, and the hot-melt adhesive is filled between the columnar conductors. The present invention is characterized in that an adhesive conductive film made of a hot-melt adhesive and a columnar conductor is formed into a ribbon shape.

〔Example〕

Embodiments of the present invention will be described with reference to FIGS. 1 to 3. A ribbon-shaped adhesive conductive film 1 consisting of a hot-melt adhesive 3 and a columnar conductor 2 is bonded to a release film 4 through a release layer 5. A columnar conductor 2 is provided by forming a film on the film and is arranged perpendicular to the film surface.
A plurality of conductors are arranged at equal intervals in a staggered manner in the ribbon direction, and the conductors of adjacent arrays are arranged at the center of the pitch of the conductor arrays adjacent to each other.

In addition, in order to construct this adhesive conductive film l, a conductive layer for forming the columnar conductive body 2 is formed on the release film 4 via the release layer 5, and then an angle equal to the direction of flow of the film is formed. After performing intersecting laser beam scribing without using a laser beam to leave a plurality of prismatic conductors 2 arranged in a staggered manner at equal intervals in the direction, the surface is coated with a hot-melt adhesive 3 to form a film. It is better to

This adhesive conductive film 1 is formed on the property film 4,
The release film 4 is peeled off during use, and the release film 4 is preferably transparent so that it will not be cut during the laser beam scribing process.
A polyethylene terephthalate film coated with a cheap and easily available silicone mold release agent as the mold release layer 5 (
D. The use of PETM type film) is most preferred.

In this case, the release film 4 on which the columnar conductor pattern is formed can be passed through a knife coater to coat the conductor pattern with a hot-melt adhesive liquid. That is, as shown in FIG. 4, a release film 4 having a pattern of columnar conductors 2 formed thereon is applied to a knife coater 10. For example, the release film 4 tightly wound around the applicator roll 12 with the conductor pattern facing upward moves in the roll rotation direction, immerses into contact with the liquid hot-melt adhesive 3 collected by the weir plate 13, and then The adhesive liquid that has adhered excessively is scraped off by the knife [1], and then the adhesive liquid is immediately passed through a drying oven to volatilize the solvent in the adhesive liquid, thereby forming a layer of hot-melt adhesive 3. can. Note that this knife coater 10 can perform relatively thick coating by adjusting the gap between the doctor knife II and the surface of the substrate to be coated, but if the adhesive layer on the conductor surface is too thick, Since conductivity after heat sealing is inhibited, bring a doctor knife 1) into contact with the conductor pattern to scrape off as much of the adhesive liquid as possible to reduce the thickness of the adhesive remaining on the conductor surface by 2 to 3 μmJJ.

It is better to lower it.

In this case, as shown in FIG. 1(A), a conductive layer may be formed by interposing an adhesive coating layer 31 of hot-melt adhesive 3 on the release layer 5 to form a conductive pattern.

Note that the method of coating the conductive pattern surface with the adhesive liquid is not limited to the above knife coater 10, but may also use a Mayer-Har coater, a wire coater, etc., and kiss-touch the substrate to be coated to the applicator roll to adhere it. It is also possible to form a coating film of a predetermined thickness by scraping off the coating liquid with a metering opening/throat or a wire-wound rod. Furthermore, the conductor pattern is formed by forming an insulating layer on the release film 4, making fine holes in a staggered pattern using YAC or laser, and injecting conductive ink into the holes by a coating method to form the conductor pattern. It is also possible to form

Further, for the release film 4, a raw material having a width several times to several tens of times as wide as the ribbon of the final product may be used, and after the conductor pattern formation and coating process have been completed, the release film 4 may be cut into a predetermined ribbon width using a slitter.

Examples of the columnar conductor 2 used in the present invention include a metal layer and a conductive resin layer. This metal layer includes Cu, yellow w41 bronze, phosphor bronze, beryllium copper nickel silver, AI,
Ni, Ti, Pb, Zn, Ta, ^g+ A
Examples include foils such as u, pt, steel, stainless steel (SO5), rattan coated films, sputtering films, etc. However, according to the present invention, since the thickness of the adhesive conductive film (10 to 50 μm) is required, foil is not used. It is preferable to use Sn!, and the surface oxide film is in a highly conductive region. 4(SnO2;2.
8X10-'Ω・cm), SUS foil (Cr02; 0
．． It is preferable to use 72 x 10-4Ω. If it is not possible to directly fix this metal foil onto the separator, a coating layer 3 of hot-melt adhesive may be applied to the release film 4. It is preferable to provide a metal foil and laminate and fix the metal foil. This hot-melt adhesive layer melts after heat-sealing and spreads around the metal foil surface processed into a columnar shape and does not interfere with conduction, but if it is too thick, it is difficult to be removed from the metal foil surface and hinders conduction. It is considered that the thickness is within 3 μm.

Further, as the conductive resin layer, conductive ink made of conductive powder, thermoplastic or thermosetting resin, solvent, etc.
This conductive powder, which can be provided by coating directly on the separator, can be carbon black, graphite powder,
Examples include Ag powder, Au powder, Cu powder, Ni powder, etc.
Examples of thermoplastic or thermosetting resins include saturated copolymerized polyester resins, polycarbonate resins, cellulose resins, polyurethane resins, acrylic resins, phenolic resins, and epoxy resins. As the solvent for dissolving these, it is preferable to use a low boiling point solvent such as toluene, methyl ethyl ketone 1 ethyl acetate, etc., which is compatible with the resin and easily disperses after coating. Coating means include gravure coating, triple reverse roll coating, doctor knife coating, etc., and the film thickness after film formation is preferably 10 to 50 μm.

The conductor pattern is formed by scribing the conductor layer with a laser beam to form a prismatic conductor on the release film. ), YAG laser (solid-state laser, thermal processing), excimer laser (rare gas laser, photochemical processing), etc. Among them, YAG laser is easy to process metals, and transparent materials can be processed in the visible light range. Since it can not be processed by a YAG laser because it also transmits a nearby YAG laser, it is preferable to use a YAG laser in the case of the present invention, in which the opaque conductor is scribed but the transparent asset film is left intact.

This YAG laser is YJIJ. (Yttrium Aluminum Garnet) A crystal in which some of the y3- ions in the crystal are replaced with Nd" ions is excited by lamp irradiation,
It is a four-level optically excited laser that stimulates the emission of photons with a wavelength of 1.06 μm, and this laser light is transmitted through an optical system (lens,
Thermal processing can be performed using a high-density energy beam focused by a mirror, etc.). The focused spot radius ρ of this laser beam is proportional to 2 as expressed by ρ=f・λ/π・w (f: focal length of lens, λ: wavelength, W: incident beam diameter), and the CO2 laser (λ=10.
6 μm) is 100-500 μm, YAG laser (
λ = 1.06 μm), the focused spot diameter is 10 to 50 μm
The former range is used for macro processing, and the L range is used for micro processing. In addition, micro-processing applications using YAG laser include laser scribing of silicon unino, laser trimming of thick film resistors, laser marking of electronic parts, etc.
In scribing, two slots with a processing width of 15 μm or more are
It is possible to drill to a depth of 50 μm or less, and the scribe line speed can be set up to 150 m/sec.

Also. , YAG laser scriber, Nd:YAG laser oscillator, ultrasonic Q switch, automatic XY table,
It consists of a processing optical system and an observation optical system, and the processing table can set the processing pinch and processing speed.

Note that YAG lasers for processing are roughly divided into continuous excitation type and pulse excitation type depending on the excitation method, but the continuous excitation type uses a Kr arc lamp as the light source and an ultrasonic light modulation element in the resonator. High-peak Q-switch pulses can be controlled at high speed, while the pulse excitation type performs Q-switching using the Pockels effect in normal pulse oscillation conditions to generate giant pulses with extremely high peak values. Obtainable.

Using the YAG laser scriber, as shown in FIG.
The scribing process is performed with a constant pinch of 0 degrees, preferably 45 degrees, and the angle is 45''.
This is preferable because the top surface of the prismatic conductor becomes square and calculation of the scribing pitch is easy. That is, assuming that the pitch of the electrodes to be connected is 0.1 m, if the pitch of the conductors in the same row in the ribbon direction is 0.1 fi or less, connection will definitely be possible, and the conductor width a in the ribbon direction (of the top surface of the prism) If the diagonal line) is equal to or less than the electrode width, lateral conduction between adjacent electrodes does not occur and connection is possible. Note that the terminal electrodes of CD panels are usually designed with a ratio of electrode width/electrode gap of 1/1, but if the conductor width a (diagonal M of the top surface of the prism) is small, the groove width of the narrow electrode gap can be reduced. Therefore, as shown in FIG. 3, it is desirable to set the groove width as the scribe width to be slightly larger than the conductor width a.

The hot-melt adhesive side 3 includes styrene-brassene-styrene (S-B-3) block copolymer, styrene-isoprene-styrene (S-IS) block copolymer, styrene-ethylene/butylene-styrene ( S-EB
-3) block copolymer 1w1 sum copolymer polyester,
Ethylene-vinyl acetate copolymer (EVA), ethylene-
Ethyl acrylate copolymer (EEA), ethylene-
Isobutyl acrylate copolymer, nylon 1). Thermoplastic resins such as nylon 12 and ionomer resins, rosin and rosin derivatives, terpene resins and modified terpene resins 9 petroleum resins, coumarone/indene resins, phenol resins, alkyd resins and other tackifiers, and epoxy resins. , isocyanate-based latent curing agents, antioxidants, stabilizers, etc., and then toluene, ethyl acetate,
A solution dissolved in a low boiling point solvent such as methyl ethyl ketone may be used.

Example-1 A 50 μm thick silicone release agent coated polyester film [Ceravir (manufactured by Toyo Metallizing ■, trade name)] and a 30 μm thick Sn foil (Nakajima Metal Foil Powder Industry ■ product) were made into a 150 w x 500 m long film. It was prepared as follows.

A hot-melt adhesive liquid was prepared by dissolving 100 parts by weight of Byron #300 (manufactured by Toyobo ■, trade name), a saturated copolymerized polyester with a glass transition point of 6°C and a ring and ball softening point of 123°C, in 200 parts by weight of toluene. Then, use a direct gravure coater to coat the release layer of Ceravir with a dry thickness of 1.
After coating with a thickness of ~2 μm, the above Sn foil was layered on top and a heater roll laminator was used to coat the film with a thickness of 15 μm.
Lamination was carried out under the conditions of 0° C., 13 kgf/cj, and 1.5 m/min.

Next, we installed a continuously pumped YAG laser oscillator with an oscillation wavelength of 1.06 μm and a maximum oscillation output of 200 mm, an ultrasonic Q-switch unit in 5L1) 6D (trade name, manufactured by NEC ■), and 5L2
31H (manufactured by NEC ■, product name), repetition frequency 1kHz, peak output 200kW, pulse width 100
Using an n5ec YAG laser scriber, cut a groove width of 40 μm across the Sn foil surface of the Sn foil laminate film at right angles to the film running direction without making an angle of 45°.
Scribing was performed at a pitch of 70 μm in the 45° direction. By this scribing process, -side 30IJ
A state was obtained in which rectangular parallelepiped conductors with a height of 30 μm were arranged at regular intervals in a staggered manner, and the transparent Cerabil and hot-melt adhesive layers were not processed due to YAG laser processing. In this case, the conductor pitch with respect to the film running direction is the conductor width a (30 μm/sin 45
'-) 42.4μm, groove width b (40μm/si
n 45°=) 56.6 μm, pitch a + b (
70μm/sin 45°=)99μm, for example, the electrode width ([56,6μm-42,4μm]/2=)8
0.1N pinch electrode with a gap of 43 μm or more,
It becomes possible to connect reliably without leaking.

A test multi-coater with knife coater specifications (Uenoyama Kiko) was applied to the patterned surface of this staggered patterned film.
A hot-melt adhesive liquid was coated using a doctor knife (manufactured by Mikuni, Ltd.) with almost zero clearance between the doctor knife and the patterned surface, and a solvent was dispersed at 120° C. for 30 seconds.

The film thus prepared was slifted into a ribbon shape with a width of 3 mm using an ink ribbon slitter, and was placed between an ITO electrode glass substrate and a gold-plated electrode epoxy resin substrate with a terminal electrode pitch Q of 1 m and an electrode width of 0.05 tm. After inserting the electrode into the tube and heat-sealing it under the conditions of 150°C and 20 kgf/c for 410 seconds, a leak check was performed between the continuity check and adjacent electrodes, and there were 0 defective points out of 1,000.6 [Effects of the Invention] This book The present invention is a ribbon-shaped adhesive type S electrical film, in which a plurality of columnar electrical conductors arranged perpendicular to the film surface are arranged at equal intervals in a staggered manner in the ribbon direction, and the electrical conductors arranged in the same manner in the ribbon direction are By placing the columnar conductors at the center of the pinch between adjacent conductor arrays and filling the spaces between the columnar conductors with hot-melt adhesive, surface contact is achieved with the electrode to be connected, resulting in a highly reliable electrical connection. In addition, since the height of the conductor is uniform and the individual conductors are reliably separated, leak defects between adjacent electrodes or local open defects will not occur.In addition, since the conductors are processed using a YAG laser, Precise microfabrication on the order of tens of micrometers and continuous processing are possible, making it possible to easily connect 0.1 pitch electrodes, i.e. connect color LCD panels, to long ribbon-shaped adhesive conductive films. It has the advantage of being easy to manufacture and can be produced at low cost.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing the case where the conductor of the embodiment of the present invention is composed of a conductive resin layer, and FIG. 1(A) is a vertical cross-sectional view showing the case where the conductor is composed of a metal layer. Figure 2 is a plan view of a part of it, Figure 3 is an explanatory plan view of the conductor pattern,
FIG. 4 is a longitudinal cross-sectional view showing an example of coating with a hot-melt adhesive. 1... Adhesive conductive film, 2... Columnar conductor, 3...
Heat-melt adhesive sublayer, 4: Release film, 5: Release layer, 10: Knife coater, 1): Doctor knife, 12: Applicator roll, 13:
Weir board. Patent, applicant Shin-Etsu Polymer Co., Ltd. Agent
Patent Attorney Pharmacist Minoru Agent Patent Attorney
1) Takatsugu Department Agent Patent Attorney Masayuki Takagi 1 Figure 1 (A) Figure 2

Claims (2)

[Claims] (1) In a ribbon-shaped adhesive conductive film, a plurality of columnar conductors arranged perpendicular to the film surface are arranged at equal intervals in a staggered manner in the ribbon direction, and the conductors arranged in the same direction in the ribbon direction are mutually connected to each other. 1. An adhesive conductive film characterized in that the columnar conductors are arranged at the center of the pitch between adjacent conductor arrays, and a hot-melt adhesive is filled between the columnar conductors. (2) A conductive layer is formed on the release film via the release layer, and then laser beam scribing is performed that intersects the film flow direction at a fixed angle. After leaving the arrayed columnar conductors, the surface is coated with a hot-melt adhesive, and the hot-melt adhesive is filled between the columnar conductors to form a film, thereby combining the hot-melt adhesive and the columnar conductors. 1. A method for producing an adhesive conductive film, characterized in that the adhesive conductive film is formed into a ribbon shape.