JP2002285136A - Electroconductive connecting film and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electroconductive connecting film capable of omitting an injecting step of a sealing resin without leaking from an adjacent electrode and easily carrying out electric connection with high reliability in a short time in connecting a semiconductor package to a substrate, and a method for producing the electroconductive connecting film. SOLUTION: This electroconductive connecting film is characterized by arranging electroconductive parts composed of a solder alloy paste comprising metal fine particles dispersed therein on a film having through-holes by screen printing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive connecting film used for electrical connection between fine electrodes and a method for manufacturing the conductive connecting film.

[0002]

2. Description of the Related Art Conventionally, in the field of electronic products such as a liquid crystal display, a personal computer, and a portable communication device, as a method of electrically connecting small parts such as a semiconductor package to a substrate, fine electrodes are opposed to each other and solder bumps are used. A connection method is generally used. When connecting such a fine counter electrode, the connection between the semiconductor package and the substrate is supported only by solder bumps, the mechanical strength is weak, and if stress occurs due to the difference in thermal strain between the semiconductor package and the substrate. Defective connection is likely to occur.

[0003] As a method of solving such a problem,
There is a method of improving the mechanical strength by sealing the periphery of the connection portion with a resin such as epoxy. Normal,
This sealing is performed by injecting a liquid sealing resin after connecting the electrodes, but since the gap between the connection portions is narrow and the viscosity of the sealing resin is high, it can be injected uniformly in a short time. It was difficult.

[0004] As a method of solving such a problem,
JP-A-63-231889, JP-A-4-2597
No. 66, JP-A-3-291807, JP-A-5
JP-A-75250 discloses an anisotropic conductive adhesive in which conductive fine particles are mixed with a binder resin to form a film or paste. However, anisotropic conductive adhesives usually have conductive fine particles randomly dispersed in the insulating adhesive, so that the conductive fine particles continue in the binder, or the conductive fine particles that are not on the opposing electrode flow during heating and pressing. There was a possibility that they would be connected and a leak would occur at an adjacent electrode. Further, even when the conductive fine particles are pressed on the electrodes or the bumps by heating and pressing, a thin layer of an insulating material is easily left between the electrodes and the conductive fine particles, so that there is a problem that the connection reliability is reduced.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above,
In the process of connecting a semiconductor package and a substrate, a step of injecting a sealing resin is omitted, there is no leakage of an adjacent electrode, and a conductive connection film capable of easily performing electrical connection with high connection reliability in a short time and its manufacture The aim is to provide a method.

[0006]

The conductive connection film of the present invention has a conductive portion made of a paste in which fine metal particles are dispersed.

As a material of the film used in the present invention, a film made of a thermoplastic, thermosetting, photocurable or photopostcurable resin is used.

[0008] Examples of the thermoplastic resin include polyolefin-based, polyamide-based, polyester-based, and polyvinyl acetal-based resins. As a polyolefin,
Although not particularly limited, for example, a single or a blend of polyethylene, polypropylene, ethylene-vinyl acetate copolymer and the like can be mentioned. If necessary, rosin, terpene resin, petroleum resin, etc. may be added as a modifier.
In addition, those obtained by copolymerizing or graft-polymerizing a carboxyl group such as acrylic acid or methacrylic acid to polyethylene or polypropylene can be used. Further, there may be mentioned those obtained by copolymerizing an ethylene-vinyl acetate copolymer with a polar group such as a hydroxyl group or a carboxyl group. The polyamide is not particularly limited, and examples thereof include nylon 11, 12 and the like. As the polyester system, although not particularly limited,
For example, a linear copolymerized polyester can be used. The polyvinyl acetal is not particularly limited, but for example, a polyvinyl acetal resin is used.

As the thermosetting resin, a mixture of a thermosetting resin and a flexible resin is used, and is not particularly limited. For example, a mixture of an epoxy resin with various polymerized nylons or a phenol resin, Examples thereof include those obtained by mixing polyvinyl acetal, nitrile rubber, and the like with a phenol resin.

Examples of the photocurable resin include those composed of a composition comprising a binder resin, a crosslinking agent, a photoinitiator and other components. Examples of the binder resin include a copolymer such as methacrylic acid ester, acrylic acid ester, and styrene, and a copolymer such as methacrylic acid, itaconic acid, and maleic acid. Examples of the crosslinking agent include acrylic acid esters of polyols, epoxy acrylates, and urethane acrylates. Anthraquinone, benzophenone and the like are added as a photoinitiator. Other components include stabilizers such as hydroquinone.

The above-mentioned photo-curable resin includes, for example, a resin comprising a polyester as a main component and a resin containing a polyether component, a cationic photopolymerizable compound, and a cationic photopolymerization initiator. As a resin containing a polyester as a main component and containing a polyether component, an ether bond is introduced into a molecule of a resin containing an ester bond of a polyhydric carboxylic acid and a polyhydric alcohol in an amount of 50 mol% or more. Can be obtained by The photocationically polymerizable compound may be any compound having at least one photocationically polymerizable functional group in the molecule, and is not particularly limited. For example, at least one epoxy group in the molecule, Various compounds having a photocationically polymerizable functional group such as an oxetane group, a hydroxyl group, a vinyl ether group, an episulfide group, and an ethyleneimine group are exemplified, and are preferably used. The cationic photopolymerization initiator may be an ionic photoacid generating type or a nonionic photoacid generating type. The cationic photopolymerization initiator of the ionic photoacid generation type is not particularly limited. Organometallic complexes such as titanocene complexes and arylsilanol-aluminum complexes are listed, and one or more of these are suitably used. Further, the nonionic photoacid generating type of cationic photopolymerization initiator is not particularly limited, for example, nitrobenzyl ester, sulfonic acid derivative, phosphoric acid ester, phenolsulfonic acid ester,
Examples thereof include diazonaphthoquinone and N-hydroxyimidosulfonate, and one or more of these are preferably used.

Among the above-mentioned film materials, a film made of a heat-curable or photo-curable resin is preferable in order to improve the adhesion after curing.

The conductive portion made of the paste in which the metal fine particles are dispersed is formed so that the conductive connection film of the present invention does not cause a connection failure when used for connection between a semiconductor package and an electrode such as a substrate. Must be arranged to conduct on both sides. Preferably, a method in which a conductive portion made of the above paste is arranged on a film in which a through-hole is provided in advance by a mechanical method such as laser or drill or a chemical method such as etching by a method described later.

As the above-mentioned metal fine particles, Au, Ag, C
u, Ni, Al, Sn, In, Zn, Pb, Ti, C
Metal fine particles made of r, Bi, or the like, or metal fine particles made of an alloy of two or more of these are used.
Preferably, a solder alloy is used because a reliable inter-electrode bonding can be performed by heating.

The size of the metal fine particles is 2 to 5
0 μm is preferred.

Examples of the paste obtained by dispersing the metal fine particles include a paste in which the metal fine particles are dispersed in a resin with a surfactant or a polymer dispersant to form a paste. As a resin for dispersing the metal fine particles,
Although not particularly limited, for example, a rosin resin, a rosin-modified resin, an epoxy resin, a phenol resin, an acrylic resin, a melamine resin and the like can be mentioned. The amount of the resin is preferably 2 to 40% by weight of the entire paste.

The paste may contain an organic solvent in order to obtain a desired viscosity. Examples of the solvent include ethanol, toluene, acetone and the like. The preferred viscosity of the paste depends on the method of arranging the conductive parts. For example, when the arrangement is performed by screen printing, 10 to 1000 Pa · s, and when the arrangement is performed by a dispenser, 1 to 100 Pa · s. s.

If necessary, the paste may contain an activator such as aniline hydrochloride or hydrazine hydrochloride, or a thixotropic agent such as wax.

The size of the conductive portion made of the paste in which the metal fine particles are dispersed depends on the density of the connection electrode using the conductive connection film.
0 μm is preferred.

The conductive connecting film of the present invention has a high fluidity, a large contact area with the electrode, and a high connection reliability since the conductive portion is made of a paste in which fine metal particles are dispersed. In addition, heat makes it easy to form a highly reliable interelectrode junction.

The thickness of the conductive connection film of the present invention is not particularly limited, but is, for example, 1 to 500 μm. The linear expansion coefficient at room temperature after curing (non-adhesive state) of the conductive connection film of the present invention is preferably 10 to 200 ppm. When the linear expansion coefficient is less than 10 ppm, the difference in linear expansion from the conductive part is large, so that when a thermal cycle or the like is applied, the electrical connection may become unstable.
Conversely, even at 200 ppm or more, when a thermal cycle or the like is applied, the gap between the electrodes is too large, and the conductive portion may be separated from the electrodes, resulting in poor connection. The coefficient of linear expansion is preferably 20 to 1
It is 50 ppm, more preferably 30 to 100 ppm. The coefficient of linear expansion depends on the resin composition of the film used.

When the conductive connection film of the present invention is uncured (has adhesiveness), a release film such as a polyethylene film or a polyester film is used to improve protection, support and handling of the conductive portion. One side or both sides may be protected.

In the conductive connection film of the present invention, it is preferable that the film is cured when the electrodes are connected. For example, the position of the electrode of the semiconductor package to be connected and the conductive portion of the conductive connection film of the present invention are aligned, and temporary crimping is performed on a circuit board such as a motherboard. Thereby, conduction between the semiconductor package and the motherboard is established. Thereafter, the film is subjected to heat curing, light curing, electron beam curing, and light post-curing, whereby the semiconductor package and the circuit board can be reliably bonded. Furthermore, in order to make the conduction between the semiconductor package electrode and the circuit board stable,
Preferably, the conductive portion is melted by a reflow process, and the conductive portion and both electrodes are joined.

[0024] A method for producing a conductive connection film, characterized in that conductive parts are arranged by screen-printing a paste containing fine metal particles on the periphery or inside of the through-hole of the film having the through-hole. Is also one of the present invention.

Further, a conductive connection is characterized in that a paste formed by dispersing metal fine particles is discharged to the periphery or inside of the through-hole of the film having the through-hole by using a dispenser, and the conductive portion is arranged. A method for producing a film is also one aspect of the present invention.

The film having a through hole used in the present invention may be the same as the material of the above-mentioned film. The size of the through hole is the same as the size of the conductive portion. Examples of the method for providing the through-hole include a mechanical method such as laser and drill, and a chemical method such as etching.

As the paste obtained by dispersing the metal fine particles used in the present invention, the same paste as the paste described above for the conductive connection film of the present invention can be used.

As a method of arranging the conductive parts by screen printing, a screen produced by a usual method is attached to a screen printing machine, and the paste is printed on a film having through holes. Specifically, the following method is mentioned. A photosensitive film having a photosensitive film formed on a film base is prepared, the photosensitive film is placed on a table with the photosensitive film face up, and a screen framed from above is mounted. Next, an adhesive is applied from the inside of the frame while pressing with a squeegee. After the adhesive has dried, the film base is peeled off. After that, a positive film is adhered to the photosensitive film surface formed on the screen,
UV exposure is performed. The pattern to be screen-printed is printed in black or the like on the positive film. After the exposure, the screen is immersed in a developing solution such as water, and the developing solution is sprayed with a spray gun to open the image area. The screen thus obtained is mounted on a screen printing machine. A film with through holes under the screen is placed in registration with the pattern on the screen. By placing the paste in which the metal fine particles are dispersed in the frame of the screen and pressing and sliding the inner surface of the screen with a squeegee, the paste is transferred onto the film, and the conductive portion can be arranged.

As a method of disposing a paste obtained by dispersing metal fine particles by using the above dispenser and disposing the conductive portion, a commonly used dispenser can be used. For example, the following method can be used. Can be
A paste obtained by dispersing metal fine particles is placed in a syringe. A needle is attached to the tip of the syringe, and the paste is discharged by operating a plunger by air pressure. A film having a through hole is placed on an XY stage. There is a syringe directly above the XY stage, and the XY stage is moved so that the hole of the film is located just below the needle. After the movement, a predetermined amount of the paste is discharged from the needle, and the hole in the film is filled with the paste. This is repeated for each hole.

The arrangement of the conductive portion is the inside and the periphery of the hole formed in the film. The conductive portion does not need to completely fill the inside of the hole, and may be in a semi-filled state.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

(Example 1) Preparation of Conductive Connection Film 64 holes were formed on a polyester film of 100 μm in thickness and 10 × 10 mm in a 0.5 mm pitch with a CO ₂ laser so that the surface diameter became 150 μm. A through-hole was provided so as to be as follows. Next, using a dispenser, a solder alloy paste was discharged into the through-holes of the film to produce a conductive connection film. The used solder alloy paste had a viscosity of 150 Pa · s and an average particle diameter of 10 μm.

Preparation of Connection Structure The obtained conductive connection film was temporarily press-bonded to a circuit board with the electrode portion of the semiconductor package and the conductive portion of the film aligned. Next, it was placed in a reflow furnace, the conductive part was melted, and the electrode part was joined to produce a connection structure. The obtained connection structure shows a stable conduction state in all the electrodes, and is -40 to 40.
The heat cycle test at 125 ° C. was performed 500 times, and no increase in the resistance value of the connection portion and no abnormality in the operation were observed at both low and high temperatures. In addition, the connection did not disconnect even after performing the drop test 40 times from a height of 3 feet.

(Example 2) Preparation of conductive connection film A thermosetting epoxy film having a thickness of 100 μm and a size of 10 × 10 mm was formed into a square at a pitch of 0.5 mm.
Through holes were formed in four holes with a CO ₂ laser so that the surface diameter became 150 μm. Next, a screen printing machine was used to print a film having a diameter of 200 μm and a thickness of 100 μ at the positions of the 64 holes on the obtained film to prepare a conductive connection film. The solder alloy paste used had a viscosity of 300 Pa · s and an average particle diameter of 10 μm.

Preparation of Connection Structure The obtained conductive connection film was temporarily press-bonded to a circuit board with the electrode portion of the semiconductor package aligned with the conductive portion of the film. Next, the semiconductor device was placed in a reflow furnace, the conductive portions were melted, the electrodes were joined, and at the same time, the epoxy-based film was thermally cured to strengthen the adhesion between the semiconductor package and the circuit board, thereby producing a connection structure. The obtained connection structure showed a stable conduction state in all the electrodes, and was subjected to a thermal cycle test at −40 to 125 ° C. 500 times. No abnormal operation was observed. The drop test from a height of 3 feet was performed 40 times, but there was no noise and there was no instantaneous disconnection.

(Comparative Example 1) An anisotropic conductive film was prepared by randomly dispersing gold-coated microspheres in an epoxy-based film, and was sandwiched between a semiconductor package and a circuit board and pressed to obtain a connection structure. . When the conduction state of each electrode was examined, conduction failure was found in 10 to 20% of the electrodes. Further, a heat cycle test at -40 to 125 ° C.
Although the test was performed 00 times, the resistance value increased at many connection portions at a high temperature.

[0037]

According to the conductive connection film of the present invention, in the step of connecting the semiconductor package and the substrate, the step of injecting the sealing resin is omitted, and there is no leakage of the adjacent electrodes and the electrical connection with high connection reliability can be achieved. It can be easily performed in a short time. Further, according to the manufacturing method of the present invention, the above-described conductive connection film can be easily manufactured at a high yield.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J004 AA04 AA10 AA12 AA13 AB03 CA04 CA06 CC02 FA05 4J040 BA201 DF001 EB001 EB131 EC001 HA066 HA076 JA09 KA03 KA32 LA09 NA20 5G307 HA02 HB03 HC01

Claims (4)

[Claims] 1. A conductive connection film having a conductive portion made of a paste in which metal fine particles are dispersed. 2. The conductive connection film according to claim 1, wherein a film made of a heat-curable or photo-curable resin has a conductive part made of a paste in which fine metal particles are dispersed. 3. A conductive connecting film, characterized in that a conductive part is arranged by screen-printing a paste obtained by dispersing metal fine particles on the periphery or inside of the through-hole of the film having the through-hole. Production method. 4. A conductive connection, wherein a paste formed by dispersing metal fine particles is discharged to the periphery or inside of the through-hole of a film having a through-hole by using a dispenser, and a conductive portion is arranged. Film production method.