CN102719814A - Conductive particle - Google Patents

Abstract

Disclosed is a conductive particle (8b) comprising: a core particle (11); a palladium layer (12) which covers the core particle (11) and which has a phosphorus concentration of between 1 wt% and 10 wt% and a thickness of between 20 nm and 130 nm; and insulating particles (1) which are disposed at the surface of the palladium layer (12) and which have a particle size of between 20 nm and 500 nm.

Description

Conducting particles

The application is to be on August 5th, 2010 applying date of original application, and application number is 201080005346.0, and denomination of invention is divided an application for the one Chinese patent application of " conducting particles ".

Technical field

The present invention relates to conducting particles.

Background technology

Install that liquid crystal drive can be divided into roughly with the mode of IC that COG (Chip-on-Glass) installs on face glass and two kinds of COF (Chip-on-Flex) installations in liquid-crystal display.

During COG installs, use the anisotropic conductive caking agent that contains conducting particles, liquid crystal directly is bonded on the face glass with IC.On the other hand, COF engages with IC liquid crystal drive in installing with the flexibility band with metal wiring, uses the anisotropic conductive caking agent that contains conducting particles that they are bonded on the face glass.Be meant the meaning that keeps insulativity in the compression aspect conducting and in non-pressurised direction in this anisotropy of mentioning.

Yet because along with the height of in recent years liquid-crystal display becomes more meticulous; Therefore carrying out thin spaceization, long-pendingization of leptoprosopy as liquid crystal drive with the convexity of the circuit electrode of IC, producing following problems: the conducting particles of anisotropic conductive caking agent flows out between the circuit electrode of adjacency and produces short circuit.

In addition; If conducting particles flows out between the circuit electrode of adjacency; Then have following problems: the conducting particles number in the anisotropic conductive caking agent of between convexity and face glass, being supplied reduces, and the connection resistance between the circuit electrode of subtend raises, and causes loose contact.

As the method that addresses these problems; Following method is arranged: like 1 illustration of following patent documentation; Through form the caking agent of insulativity in the one side at least of anisotropic conductive caking agent; Prevent that COG from installing or the method for the reduction of the bond quality that COF installs and as 2 illustrations of following patent documentation, with the method on the whole surface of the overlay film coated electroconductive particles of insulativity.

In the following patent documentation 3,4, illustration with the covered method of nuclear particle of high molecular polymer of gold layer lining of the seed of insulativity.In addition, in the following patent documentation 4, also illustration form the method for functional group with the surface of the gold layer of the compound treatment tegmental nuclei particle of arbitrary group and at golden laminar surface with sulfydryl, sulfenyl, disulfide group.Thus, can on the gold layer, form firm functional group.

In the following patent documentation 5, as a kind of trial that improves the electroconductibility of conducting particles, illustration on resin particle, carry out the method for copper/golden plating.

In the following patent documentation 6; Illustration a kind ofly possess non-metal particle, the metal level lining non-metal particle, that contain the above copper of 50 weight %, the nickel dam of coated metal layer; Golden layer conducting particles with the lining nickel dam; And have following record: according to this conducting particles, and compared with the general conducting particles that constitutes of gold by nickel, electroconductibility is good.

In the following patent documentation 7, have following record: a kind of electroconductive particle of the coating metal layer that has the base material particulate and on the aforementioned substrates particulate, be provided with is characterized in that the containing ratio of the gold in the aforementioned metal coating is below the above 99 weight % of 90 weight %.

The prior art document

Patent documentation

Patent documentation 1: japanese kokai publication hei 08-279371 communique

Patent documentation 2: No. 2794009 communique of japanese

Patent documentation 3: No. 2748705 communique of japanese

Patent documentation 4: No. 03/02955 pph of International Publication

Patent documentation 5: TOHKEMY 2006-028438 communique

Patent documentation 6: TOHKEMY 2001-155539 communique

Patent documentation 7: TOHKEMY 2005-036265 communique

Summary of the invention

The problem that invention will solve

But, shown in above-mentioned patent documentation 1, with regard to the method for the caking agent that forms insulativity in the one side of circuit connecting section part, in protruding narrowization of area to less than 3000 μ m ²Situation under, in order to obtain stable connection resistance, need to increase the conducting particles in the circuit connecting section part.When increase conducting particles like this,, still has room for improvement about the insulativity between adjacent electrode.

In addition; Shown in above-mentioned patent documentation 2; With regard to for improve between adjacent electrode insulativity and for the method on the whole surface of the overlay film coated electroconductive particles of insulativity, though exist insulativity between circuit electrode to uprise the such problem of the easy step-down of electroconductibility of conducting particles.

In addition, like above-mentioned patent documentation 3, shown in 4, with regard to regard to the method on the sub-coated electroconductive particles of the seed of insulativity surface, because therefore the problem of seed and the cementability of conducting particles needs to use resinous seed such as vinylformic acid.In this case, make the sub-fusion of resinous seed make conducting particles contact two circuit each other the time, between circuit, obtain conducting through the thermo-compressed circuit.Known: at this moment, if the surface of the resin-coated conducting particles of fused seed son is then same with the method with the whole surface of the overlay film coated electroconductive particles of insulativity, the easy step-down of the electroconductibility of conducting particles.Because this reason,, be suitable for using the particle that hardness is higher and melt temperature is high of inorganic oxide etc. as seed of insulativity.For example, in the above-mentioned patent documentation 4, illustration handle silica sphere, make silicon-dioxide that has NCO from the teeth outwards and the method that has amino conducting particles reaction from the teeth outwards with 3-isocyanic ester propyl-triethoxysilicane.

But, use the modified with functional group particle diameter generally comparatively difficult as the surface of the particle below the 500nm.In addition, when carrying out spinning after with modified with functional group and filtering, inorganic oxide accumulative problems such as silicon-dioxide take place easily.In addition, with regard to 4 illustrative methods of above-mentioned patent documentation, the lining rate of seed of control insulativity is difficulty comparatively.

In addition; Have in use under the situation of compound treatment metallic surface of arbitrary group of sulfydryl, sulfenyl, disulfide group; Even on metal, there is the metal of the so easy oxidation of base metal such as nickel or the copper of very small amount, the reaction of metal and compound also is difficult to carry out.

In addition, the inventor distinguishes through research: under the situation of inorganicss such as lining silicon-dioxide on the conducting particles, the metallic surface of squeezing on the bad conducting particles owing to silicon-dioxide presents electroconductibility.Therefore, because silicon-dioxide destroys conducting metal,, then has the tendency that migrate attribute worsens if therefore the material beyond the precious metal is sneaked into conducting metal.

In addition, shown in above-mentioned patent documentation 6, becoming main flow, in this type conducting particles, having the nickel stripping, cause the problem that migration is such though on nickel dam, carry out the conducting particles of gold-plated type in recent years.In addition, if be below the 40nm with gold-plated thickness setting, then this tendency becomes more obvious.

In addition, shown in above-mentioned patent documentation 7, be the conducting particles of the coating metal layer lining more than the 90 weight % with the content of gold, though good aspect safety, cost is high.Therefore, the conducting particles that possesses the high coating metal layer of gold content hardly conforms with practicality, in recent years, has the tendency of the gold content that reduces the coating metal layer.Relative therewith, the conducting particles that possesses copper coating is excellent on electroconductibility, cost.But, with regard to the conducting particles that possesses copper coating,, therefore consider then existing problems from anti-hygroscopic viewpoint owing to move easily.Therefore, carried out trial for the shortcoming that remedies the two (Jin Hetong), still, all incomplete.For example, with regard to the method shown in the above-mentioned patent documentation 5, can not remedy the shortcoming of the two (Jin Hetong) fully.

The present invention accomplishes in view of above-mentioned problem, and its purpose is, provides a kind of and can not cause migration, cost is cheap and the excellent conducting particles of high, the interelectrode connection reliability of electroconductibility.

Solve the method for problem

In order to reach above-mentioned purpose, first conducting particles involved in the present invention possesses that nuclear particle (resin particle) and tegmental nuclei particle, phosphorus concentration are below the above 10 weight % of 1 weight %, thickness is the following palladium layer of the above 130nm of 20nm.In other words; First conducting particles involved in the present invention is characterised in that, the conductive layer that possesses resin particle and form on the surface of resin particle, and conductive layer is the palladium layer that contains phosphorus; Phosphorus concentration in the palladium layer is that the thickness of palladium layer is below the above 130nm of 20nm below the above 10 weight % of 1 weight %.The invention is characterized in that above-mentioned palladium layer directly is formed at the surface of resin particle.In other words, among the present invention, (for example: nickel) preferably there is not palladium metal in addition on the surface of resin particle.This characteristic of the present invention is indispensable reaching on the following effect of the present invention.

Among above-mentioned first the present invention, owing to the palladium layer is ductile, therefore when connecting pair of electrodes, even conducting particles compression back palladium layer also is being difficult to break with the anisotropic conductive caking agent that possesses above-mentioned conducting particles.Therefore, the electroconductibility and the interelectrode connection reliability of the conducting particles after the compression can be improved, and the migration of the disruptive palladium of palladium layer can be prevented to result from.In addition, palladium, compare cheaply with precious metals such as gold, platinum, and practical.Therefore, above-mentioned first conducting particles involved in the present invention that possesses the palladium layer compared with the conducting particles that only uses gold or platinum, and cost is low.

Among above-mentioned first the present invention,, therefore can access sufficient electroconductibility because the thickness of palladium layer is more than the 20nm.

Among above-mentioned first the present invention,, therefore can access the hardness height owing to contain the phosphorus below the above 10 weight % of 1 weight % in the palladium layer, be absorbed in relatively to electrode surface and conducting film with abundant intensity.

Second conducting particles involved in the present invention possesses nuclear particle; Tegmental nuclei particle, phosphorus concentration are below the above 10 weight % of 1 weight %, thickness is the following palladium layer of the above 130nm of 20nm and at the surface configuration of palladium layer, the insulativity particle that particle diameter is 20 ~ 500nm.

The anisotropic conductive caking agent (anisotropic conductive film) that will obtain when will in caking agent, disperseing a plurality of above-mentioned conducting particless is configured between the pair of electrodes and when pair of electrodes connected (thermo-compressed); On vertically (pair of electrodes relatively to direction), conducting particles is all compressed by pair of electrodes.Consequently, the insulativity particle is absorbed in the nuclear particle side from the palladium laminar surface, and the palladium layer that thereupon exposes can contact with pair of electrodes.That is, the palladium layer through conducting particles makes conducting between pair of electrodes.On the other hand, laterally (with pair of electrodes relatively to the vertical direction of direction) on, the insulativity particle that each conducting particles possesses is between the conducting particles of adjacency, the insulativity particle contacts with each other.Therefore, in the horizontal, above-mentioned pair of electrodes and and the electrode of their adjacency between keep insulativity.

Among above-mentioned second the present invention, therefore same because the palladium layer is ductile with above-mentioned first the present invention, the electroconductibility and the interelectrode connection reliability of the conducting particles after the compression can be improved, and the migration of palladium can be prevented.In addition, palladium is compared cheaply with precious metals such as gold, platinum, and practical.Therefore, possess above-mentioned second conducting particles involved in the present invention of palladium layer, compare with the conducting particles that only uses gold or platinum, cost is low.

Among above-mentioned second the present invention and since possess as conductive layer, thickness is the palladium layer more than the 20nm, therefore can access sufficient electroconductibility.

Among above-mentioned first and second the present invention, preferred palladium layer is the palladium layer of reduction plating type.Thus, the palladium layer improves for the lining rate of nuclear particle, thereby improves the electroconductibility of conducting particles easily.

In addition,, therefore can on resin particle, form the palladium layer of fine and close homogeneous, few conducting particles that exposes on resin particle surface can be provided because the palladium layer is the palladium layer of reduction plating type.In addition, can at random set the thickness of palladium layer according to the amount of plating bath.That is can with the gauge control of palladium layer the thickness that suits the requirements.

In the invention described above, the composition in the conductive layer (the elementary composition and phosphorus concentration of conductive layer) preferably carries out qualitative and quantitative through energy dispersion type X ray optical spectroscopy (Energy Dispersive X-ray Spectroscopy:EDX).

Among above-mentioned first and second the present invention, preferred insulativity particle is a silicon-dioxide.The insulativity of the insulativity particle that is made up of silicon-dioxide is excellent, controls particle diameter easily, and cheap.In addition, when silicon-dioxide being dispersed in obtain the water-dispersion colloidal silica in the water, because its surface has hydroxyl, therefore the associativity with the palladium layer is excellent.In addition, the hydroxyl of silica sphere is also excellent with the associativity of the functional group that forms on the surface of palladium layer.Therefore, the insulativity particle that is made up of silicon-dioxide can be adsorbed on the surface of palladium layer or gold layer securely.

The invention effect

According to the present invention, a kind of cheap and excellent conducting particles of high, the interelectrode connection reliability of electroconductibility of migration, cost that can not cause can be provided.

Description of drawings

Fig. 1 is the general profile chart of the related conducting particles of first embodiment of the present invention;

Fig. 2 is the general profile chart of the related conducting particles of second embodiment of the present invention;

Fig. 3 (a) is the general profile chart that possesses the anisotropic conductive caking agent of the related conducting particles of second embodiment of the present invention, and Fig. 3 (b) and Fig. 3 (c) are the general profile chart that is used to explain the making method of the syndeton body that has used the anisotropic conductive caking agent.

Embodiment

Below, specify the best mode that is used to carry out an invention.But the present invention is not limited to following embodiment.

[first embodiment]

(conducting particles)

As shown in Figure 1, the related conducting particles 8a of first embodiment of the present invention possesses that nuclear particle 11 and tegmental nuclei particle are 11 all, thickness is below the above 130nm of 20nm, phosphorus concentration is the following palladium layers 12 of the above 10 weight % of 1 weight %.Below, the related conducting particles 8a of first embodiment remembers work " coatingparticles 2a " according to circumstances.

< nuclear particle 11 >

The particle diameter of the nuclear particle 11 that uses among the present invention preferably less than after state first electrode 5 of Fig. 3 and the minimum interval between second electrode 7.In addition, under height (interval of the electrode) situation devious of electrode, the particle diameter of nuclear particle 11 is preferably greater than the deviation (largest interval of electrode) of height.From these reasons, the particle diameter of nuclear particle 11 is preferably 1 ~ 10 μ m, is more preferably 1 ~ 5 μ m, is preferably 2.0 ~ 3.5 μ m especially.

Though the nuclear particle in the conducting particles in the past is the particle that only is made up of metal or the particle that is made up of organism or inorganics any, the nuclear particle 11 in this embodiment is the resin particles that are made up of resin.

As organic nuclear particle 11; Not special restriction, the resin particle that preferably constitutes by polyolefin resines such as vinyl resins such as polymethylmethacrylate, polymethyl acrylate, Vilaterm, Vestolen PP 7052, polyisobutene, polyhutadiene, PS, divinyl benzene polymers, Vinylstyrene-styrol copolymer, benzoguanamine formaldehyde resin etc.

< palladium layer 12 >

Because palladium layer 12 is ductile, therefore behind compression conductive particle 8a, be difficult to cause that metal breaks, also be difficult to cause and follow the metal disruptive to move.In addition, palladium layer 12 is compared with copper with base metal, and acid resistance and alkali resistance are excellent.In addition, because palladium layer 12 is for containing the alloy of phosphorus, so acid resistance and alkali resistance excellence more.Therefore, can with after the functional groups such as sulfydryl, sulfenyl or disulfide group that state stably combine.In addition, with regard to regard to the associativity of these functional groups, palladium and gold and platinum have same tendency, but with equal volume relatively during these precious metals, palladium is the most cheap, and practical.In addition, palladium layer 12 excellent electric conductivity.From these reasons, palladium layer 12 is suitable for the metal level as tegmental nuclei particle 11.

From connecting the viewpoint of resistance, the phosphorus concentration in the palladium layer 12 is below the above 10 weight % of 1 weight %, is preferably below the above 8 weight % of 1 weight %, is more preferably below the above 6 weight % of 1 weight %.In addition, compare the palladium layer hardness that contains phosphorus high (with reference to non-patent literature 1 " sufacing, P 651, Vol 55, No 10,2004 ") with not phosphorous pure palladium layer.If the hardness of the palladium laminar surface that contacts with electrode is high, then conducting particles is absorbed in electrode surface easily, poke oxidation electrode, guarantee conduction property easily.On the other hand, surpass under the situation of 10 weight % at the containing ratio of phosphorus, the conducting resistance of palladium layer is excessive.In addition, surpass under the situation of 10 weight % at the containing ratio of phosphorus, when for example plating formed palladium layer 12, the palladium plating was difficult to carry out, and the time that plating process needs is long.

Palladium layer 12 is preferably the palladium layer of reduction plating type.Thus, palladium layer 12 improves for the lining rate of nuclear particle 11, and the electroconductibility of conducting particles 8a more improves.Be used to make the phosphorus eutectoid, make the reductive agent of palldium alloyization preferably comprise the reductive agent that Hypophosporous Acid, 50 and salt thereof, phosphorous acid and salt thereof etc. contain phosphorus at least.As reductive agent, as long as comprise the aforesaid reductive agent that contains phosphorus, then also can contain other reductive agent, not special the qualification.Known: even under the situation of the reductive agent that contains other owing to contain the reductive agent of phosphorus, phosphorus also can eutectoid to palladium film in.

Through using the reduction plating, control the plated thickness of palladium layer 12 easily.For example,, therefore can not use useless palladium and reagent because the palladium ion concentration that can from the plating bath that uses, contain is calculated the plated thickness after separating out in advance, thus cost degradation.

The thickness of palladium layer 12 is below the above 130nm of 20nm, is preferably below the above 100nm of 20nm, is more preferably below the above 80nm of 20nm.If the thickness of palladium layer less than 20nm, then can not obtain sufficient electroconductibility.On the other hand, if the thickness of palladium layer 12 surpasses 130nm, the tendency that then has nuclear particle 11 whole elasticity to reduce.If the whole elasticity of coatingparticles 2a reduces, then when conducting particles 8a by pair of electrodes clamp, and when being pushed down in the vertical, the elasticity owing to coatingparticles 2a is difficult to obtain palladium layer 12 and overlays the effect at electrode surface fully.Therefore, the contact area of palladium layer 12 and two electrodes diminishes, the tendency that has effect of the present invention that interelectrode connection reliability is improved to diminish.In addition, palladium layer 12 is thick more, and cost is high more; Not only not preferred economically; And when crimping is installed, sometimes at the conductive layer of the conducting particles 8a that is clamped by pair of electrodes and pushed down in the vertical, be to produce on the palladium layer 12 to break the tendency that has interelectrode connection resistance to rise.

(analysis of coating)

For the composition analysis of the palladium layer 12 on tegmental nuclei particle 11 surface, can use the atom extinction photometer.For example, following method is arranged: use the analysis of atom extinction photometer to dissolve the liquid of palladium layer 12 gained, measure concentration of metal ions and also calculate with acid etc.In addition, also can use the ICP apparatus for analyzing luminosity to analyze palladium layer 12.If use the ICP apparatus for analyzing luminosity, then also can carry out qualitative analysis the time phosphorus quantitatively.In addition, the phosphorus concentration in the palladium layer 12 also can use EDX to carry out quantitatively.In addition, owing to obtained information through the mensuration of the EDX under the low range from a plurality of particles, the EDX under the therefore preferred high magnification measures.

[second embodiment]

Next, the related conducting particles of second embodiment of the present invention, and the method for manufacture of conducting particles are described.In addition, below, the difference of above-mentioned first embodiment and second embodiment only is described, relevant the two identical item is omitted explanation.

(conducting particles)

As shown in Figure 2, the related conducting particles 8b of second embodiment not only possesses nuclear particle 11 and palladium layer 12, also possesses a plurality of insulativity particles 1 in the surface configuration of palladium layer 12, and at that point, the conducting particles 8a related with first embodiment is different.

< insulativity particle 1 >

Insulativity particle 1 is preferably inorganic oxide.Suppose that insulativity particle 1 is the situation of organic cpds, insulativity particle 1 distortion in the production process of anisotropic conductive caking agent has the easy tendency that changes of characteristic of the anisotropic conductive caking agent of gained.

As the inorganic oxide that constitutes insulativity particle 1, preferably contain the oxide compound of at least a element of the group that is selected from silicon, aluminium, zirconium, titanium, niobium, zinc, tin, cerium and magnesium composition.These oxide compounds can use separately or mix more than 2 kinds and use.In addition, as inorganic oxide, in containing the oxide compound of above-mentioned element, excellent, the water-dispersion colloidal silica (SiO that controlled particle diameter of insulativity most preferably ₂).

As the commercially available article of the insulativity particle that constitutes by such inorganic oxide (below be called " inorganic oxide particle "), for example can enumerate: SNOWTEX, SNOWTEX UP (daily output chemical industry (strain) is made), QUARTRON PL series (Japan's chemical industry (strain) manufacturing) etc.

The particle diameter of inorganic oxide particle is preferably little than resin particle.Particularly, the median size of inorganic oxide particle is 20 ~ 500nm, is preferably 30 ~ 400nm, is more preferably 40 ~ 350nm.In addition, the particle diameter of inorganic oxide particle uses the specific surface area scaling method or the X ray small angle scattering method that adopt the BET method to measure.If the inorganic oxide particle that particle diameter less than 20nm, then is adsorbed on the coatingparticles 2a does not play a role as insulating film, an interelectrode part has the tendency that is short-circuited.On the other hand, if particle diameter surpasses 500nm, then because when crimping was installed, the conductive layer (palladium layer 12) of electrode and conducting particles 8b contacted difficulty, therefore interelectrode connection resistance uprises, and the tendency that can not obtain good electrical conductivity is arranged.

(method of manufacture of conducting particles)

The method of manufacture of the conducting particles 8a that first embodiment of the present invention is related possesses the operation (S1) that forms palladium layer 12 on the surface of nuclear particle 11.The method of manufacture of the conducting particles 8b that second embodiment of the present invention is related; Behind operation S1; Possess: use the surface of the compound treatment palladium layer 12 of arbitrary group, form the operation (S2) of functional group on the surface of palladium layer 12 with sulfydryl, sulfenyl or disulfide group; Handle the operation (S3) on the surface of the palladium layer that is formed with functional group with polymer electrolyte; With through chemisorption, be formed with functional group and handle with polymer electrolyte after the operation (S4) of surperficial fixed insulation property particle 1 of palladium layer 12.In addition, below, insulativity particle 1 is described for the situation that is formed with the inorganic oxide particle of hydroxyl on the surface.

<S1>

At first, form palladium layer 12, obtain coatingparticles 2a (the conducting particles 8a that first embodiment is related) on the surface of nuclear particle 11.As its concrete method, for example can enumerate the plating that adopts palladium.In this plating process, after the surperficial degreasings to nuclear particle 11 such as alkali,, carry out the surface adjustment of nuclear particle 11 with the acid neutralization.Can give palladium catalyst, carry out reduced form through the above-mentioned catalyzer that contains phosphorus and not have electrolysis palladium plating thereafter.Do not have the composition of electrolysis palladium plating solution as reduced form, preferably be added with the palladium plating solution of water-soluble palladium salt, (2) reductive agent, (3) complexing agent and (4) pH regulator agent of (1) palladous sulfate and so on.As the phosphorus concentration in the palladium layer 12 being adjusted into the method below the 10 weight % more than the 1 weight %, for example can use adjustment to constitute the method for the composition shown in (1) to (4) of the palladium plating solution shown in above-mentioned.Especially, can enumerate the selected method that contains the pH of the method for the reductive agent of phosphorus, the method for adjusting this reduction dosage, the reaction of control plating, adjust the method for the phosphorus concentration in the control palladium plating solution of method etc. of plating temperature etc.In addition, the kind of adjustment complexing agent, the method for concentration also can be adjusted phosphorus concentration.Wherein, because reaction control is excellent, therefore can use the method for the pH of control plating reaction suitably.Method shown in above-mentioned can be used separately, if but phosphorus concentration is then adjusted in combination respectively easily, also control the stability of plating bath easily.

<S2>

Under the situation that forms the related conducting particles 8b of second embodiment, further, usefulness has the surface for the compound treatment palladium layer 12 of arbitrary group of sulfydryl, sulfenyl or the disulfide group of palladium formation co-ordination bond.Thus, form functional group on the surface of palladium layer 12.

As the compound that in the surface treatment of palladium layer 12, uses, particularly, can enumerate Thiovanic acid, 2 mercapto ethanol, Methyl Thioglycolate, dimercaptosuccinic acid, thioglycerol, thioserine etc.Functional group as the surface at the palladium layer of crossing with these compound treatment 12 forms can enumerate hydroxyl, carboxyl, alkoxyl group or alkoxy carbonyl.

Easy and thiol group (sulfydryl) reaction of palladium, relative therewith, the base metal of nickel and so on is difficult to react with thiol group.Therefore, the palladium particle of this embodiment (by the nuclear particle 11 of palladium layer 12 lining) is compared easy and thiol group reaction with the nickel/gold particle (by the nuclear particle of nickel dam with the lining of gold layer) of existing type.In addition, for nickel/gold particle,, then has the tendency that the ratio of the nickel of particle surface uprises if the thickness of gold layer is below the 30nm.

As concrete grammar, for example can enumerate compounds such as the Thiovanic acid about 10 ~ 100mmol/l being dispersed in the organic solvents such as methyl alcohol, ethanol and in the liquid that obtains, disperse the method for palladium particle with the surface of above-mentioned compound treatment palladium layer 12.

<S3、S4>

Then, after handling the surface of the palladium layer 12 that is formed with functional group, at the surface chemistry absorption insulativity particle 1 of palladium layer 12 with polymer electrolyte.

If, then having the surface potential (ξDian Wei) of palladium layer 12 of the functional group of hydroxyl, carboxyl, alkoxyl group or alkoxy carbonyl and so at neutral range, pH is generally negative.On the other hand, for the surface of the insulativity particle 1 on the surface that is adsorbed on palladium layer 12 in the subsequent handling, owing to contain inorganic oxide with hydroxyl, so the surface potential of insulativity particle 1 is usually also for negative.In this case, surface potential being arranged is that the insulativity particle of bearing 1 is difficult to be adsorbed on every side the tendency of surface potential for negative palladium layer 12.Therefore, through the surface of handling palladium layer 12, make surface being insulated property particle 1 lining easily of palladium layer 12 with polymer electrolyte.

As the method on the surface of the palladium layer 12 after insulativity particle 1 being adsorbed on handle, preferably in the method for range upon range of polymer electrolyte of the surface interaction of palladium layer 12 and inorganic oxide with polymer electrolyte.More specifically, through carrying out following operation (1), (2) in order, can make its surperficial part by the range upon range of insulativity that polymer electrolyte and inorganic oxide particle arranged by the coatingparticles 2a of overlay film lining, be conducting particles 8b.

Operation (1): the coatingparticles 2a that will have functional group on the surface of palladium layer 12 is dispersed in the polymer electrolyte solution, make polymer electrolyte be adsorbed on the surface of palladium layer 12 after, the operation of rinsing coatingparticles 2a.

Operation (2): the coatingparticles 2a after the rinsing is dispersed in the dispersion soln of inorganic oxide particle, make inorganic oxide particle be adsorbed on the surface (palladium layer 12) of coatingparticles 2a after, the operation of rinsing coatingparticles 2a.

That is, in operation (1), form polyelectrolyte film on the surface of coatingparticles 2a; In operation (2), across polyelectrolyte film, through chemisorption, at the surperficial fixed inorganic oxide fine particle of coatingparticles 2a.Through using this polyelectrolyte film, the surface of the enough inorganic oxide particle zero defects of ability and the coatingparticles 2a that is covered equably.Use through such operation (1), the conducting particles that (2) obtain and prepare the anisotropic conductive caking agent; If use this anisotropic conductive caking agent to come the junction circuit electrode; Even then circuit electrode is spaced apart thin space and also can guarantees insulativity, it is low and good between the electrode that is electrically connected, to connect resistance.

Method with above-mentioned operation (1), (2) is called interaction cascading method (Layer-by-Layer assembly).The interaction cascading method is the method that forms organic film that equaled to deliver in 1992 by G.Decher (with reference to ThinSolid Films, 210/211, p831 (1992)).

In this interaction cascading method; Through mutual dipping base material in the aqueous solution of positively charged polymer dielectric (polycation) and electronegative polymer dielectric (polyanion); Utilize the polycation of electrostatic attraction absorption and the group of polyanion in the substrate laminated, obtain composite package (interaction cascading film).

In the interaction cascading method; Because through electrostatic attraction, the material that has opposite charges on substrate in the electric charge of formed material and the solution attracts each other and carries out film and grow, so; Along with the carrying out of absorption charge neutralization takes place, then further absorption will no longer take place.Therefore, if reach a certain saturation point, the thickness of film just can further not increase.

Lvov etc. have reported following method: the interaction cascading method is applied to particulate; Use each particle dispersion liquid of silicon-dioxide, titanium oxide, cerium dioxide; And through the range upon range of polymer electrolyte (with reference to Langmuir Vol.13, (1997) p 6195 ~ 6203) that has the electric charge opposite of interaction cascading method with the surface charge of particulate.

If use this method; The particulate of the silicon-dioxide through the negative surface charge of range upon range of band alternatively and as with the diallyl dimethyl ammoniumchloride (PDDA) of the polycation of its opposite charges or polymine (PEI) etc. then, the particulate laminate film of can form interaction cascading silicon dioxide microparticle and polymer electrolyte.

In the method for manufacture of the conducting particles 8b that second embodiment is related; Preferably behind the dispersion liquid that impregnated in polymer electrolyte solution or inorganic oxide particle and before impregnated in the particle dispersion liquid or polymer electrolyte solution of oppositely charged; Through only using solvent rinsing coatingparticles 2a, wash the dispersion liquid of remaining polymer electrolyte solution or inorganic oxide particle off from coatingparticles 2a.

Because the polymer electrolyte and the inorganic oxide particle that on coatingparticles 2a, adsorb are the surface of electrostatic adhesion at coatingparticles 2a, therefore can be in this rinsing process from the sur-face peeling of coatingparticles 2a.But; If remaining polymer electrolyte or inorganic oxide particle that coatingparticles 2a does not adsorb are put in the solution of the band electric charge opposite with these; Then positively charged ion, negatively charged ion mix in the solution, cause the gathering and the deposition of polymer electrolyte and inorganic oxide particle sometimes.Through rinsing, can prevent such unfavorable condition.

As the solvent that is used for rinsing, water, alcohol, ketone etc. are arranged, but start from the viewpoint of the dispersion liquid of removing superfluous polymer electrolyte solution or inorganic oxide particle easily, use than resistance value usually to be the ion exchanged water more than the 18M Ω cm (so-called ultrapure water).

Polymer electrolyte solution is the solution that in the mixed solvent of water or water and water miscible organic solvent, is dissolved with polymer electrolyte.As the water miscible organic solvent that can use, for example can enumerate methyl alcohol, ethanol, propyl alcohol, acetone, N, acetonitrile etc.

As polymer electrolyte, can use in the aqueous solution ionized and have a polymer of charged functional group at main chain or side chain.In this case, can use polycation.

As polycation; Generally can use the material with functional group that can be positively charged of polyamine class etc. and so on, for example polymine (PEI), polyallylamine hydrochloride (PAH), diallyl dimethyl ammoniumchloride (PDDA), polyvinyl pyridine (PVP), polylysine, SEPIGEL 305 and contain their multipolymer more than at least a kind etc.

In the polymer electrolyte, the electric density height and the bonding force of polymine are strong.For fear of electromigration and corrosion; In these polymer electrolytes, the material of preferred alkali-free metal (Li, Na, K, Rb, Cs) ion and alkaline-earth metal (Ca, Sr, Ba, Ra) ion, halide ions (fluorion, cl ions, bromide anion, iodide ion).

These polymer electrolytes are the compound of the mixed solution of water miscible compound or water soluble and organic solvent; Molecular weight as polymer electrolyte; According to the kind of used polymer electrolyte and can not confirm entirely, generally be preferably about 500～200000.In addition, the concentration of the polymer electrolyte in the solution generally is preferably about 0.01～10 weight %.In addition, the not special restriction of the pH of polymer electrolyte solution.

Kind, molecular weight or the concentration of the polyelectrolyte film through adjustment lining coatingparticles 2a can be controlled the lining rate of inorganic oxide particle.

Particularly, use the occasion of the high polyelectrolyte film of electric density such as polymine, the tendency that has the lining rate of inorganic oxide particle to uprise; Use the occasion of the low polyelectrolyte film of electric density such as diallyl dimethyl ammoniumchloride, the tendency of the lining rate step-down of inorganic oxide particle is arranged.

In addition, the occasion that the molecular weight of polymer electrolyte is big, the tendency that has the lining rate of inorganic oxide particle to uprise, and can make inorganic oxide particle be adsorbed in palladium layer 12 securely.From the occasion that the such viewpoint of bonding force is considered, the molecular weight of preferred polymer electrolyte is more than 10000.On the other hand, the occasion that the molecular weight of polymer electrolyte is little has the tendency of the lining rate step-down of inorganic oxide particle.

In addition, use the occasion of polymer electrolyte, the tendency that has the lining rate of inorganic oxide particle to uprise with high density; With the occasion of lower concentration use polymer electrolyte, the tendency of the lining rate step-down of inorganic oxide particle is arranged.The high occasion of lining rate of inorganic oxide particle has the tendency of insulativity height, poorly conductive, and the low occasion of lining rate of inorganic oxide particle has the tendency of electroconductibility height, poor insulativity.

The inorganic oxide particle one deck that can only be covered.If multilayer laminated, then be difficult to control lamination amount.In addition, the lining rate on palladium layer 12 surface of inorganic oxide particle is preferably 20～100% scope, is more preferably 30～60% scope.

Alkalimetal ion in the dispersion soln of inorganic oxide particle and alkaline-earth metal ionic concentration are preferably below the 100ppm.Thus, improve the interelectrode insulating reliability of adjacency easily.In addition, as inorganic oxide particle, be suitable through the hydrolysis reaction of metal alkoxide, the inorganic oxide particle of so-called sol-gel manufactured.

Particularly as inorganic oxide particle, preferably water is disperseed colloidal silica (SiO ₂).Because the water-dispersion colloidal silica has hydroxyl on the surface, therefore the associativity with coatingparticles 2a is excellent, and makes particle diameter consistent easily, and cheap, from above-mentioned viewpoint, inorganic oxide particle is suitable.

Known hydroxyl general and hydroxyl, carboxyl, alkoxyl group, alkoxy carbonyl form firm key.As the particular type of the key of hydroxyl and these functional groups, can enumerate and result from the covalent linkage or the hydrogen bond of dehydrating condensation.Therefore, the inorganic oxide particle that has a hydroxyl on the surface can be adsorbed on the palladium layer 12 (coatingparticles 2a surface) of functional groups such as being formed with hydroxyl, carboxyl, alkoxyl group, alkoxy carbonyl securely.

In addition, though the hydroxyl on the surface of inorganic oxide particle can enough silane coupling agents etc. be modified as amino, carboxyl, epoxy group(ing), the particle diameter of inorganic oxide be situation below the 500nm next be difficult.Therefore, it is desirable to not carry out functional group modification and with inorganic oxide particle lining coatingparticles 2a.

The conducting particles 8b that utilizes above method to accomplish through heat drying, further heavy insulation property particle l and coatingparticles 2a's combines.As the reason that bonding force increases, for example can enumerate: the dehydrating condensation of the amino that the Chemical bond of functional group such as the carboxyl on palladium layer 12 surface and the hydroxyl on insulativity particle l surface or the carboxyl on palladium layer 12 surface and insulativity particle l are surperficial is promoted.In addition, if heat in a vacuum, then preferred from preventing viewpoint that metal gets rusty.In addition, even the outmost surface of coatingparticles is the situation of gold layer, also the situation with palladium layer 12 is the same, and through heat drying, further heavy insulation property particle and coatingparticles combines.

The temperature of heat drying is preferably 60～200 ℃, is preferably 10～180 minutes heat-up time.Temperature is lower than 60 ℃ situation or is less than heat-up time under 10 minutes the situation, and insulativity particle l peels off from coatingparticles 2a easily, and temperature surpasses 200 ℃ situation or surpasses heat-up time under 180 minutes the situation, and coatingparticles 2a easy deformation is therefore not preferred.

(observation of particle) can be used scanning electron microscope (SEM, Scanning Electron Microscope) for the plated film (palladium layer) of coated with resin particulate, the observation of disposed insulation property particle etc. on plated film.Can confirm allocation position and number of coated surface, insulating fine particles etc. through image.

(anisotropic conductive caking agent)

Through will shown in Fig. 3 (a), being dispersed in the caking agent 3, can access anisotropic conductive caking agent 40 by the conducting particles 8b that above method is made.Use the making method of the syndeton body 42 of this anisotropic conductive caking agent 40 to be shown in Fig. 3 (b), (c).In addition, among Fig. 3 (a), 3 (b), 3 (c), conducting particles 8b note is made conducting particles 8.In addition, owing to carried out simpleization of figure, omit the palladium layer 12 that conducting particles 8 possesses.

Shown in Fig. 3 (b), prepare first substrate 4 and second substrate 6, anisotropic conductive caking agent 40 is configured between two substrates.At this moment, make second electrode 7 that first electrode 5 that first substrate 4 possesses and second substrate 6 possess relatively to.Then, first electrode 5 and second electrode 7 relatively to direction, pressurized, heated first substrate 4 and second substrate 6 and two substrates are range upon range of obtain the syndeton body 42 shown in Fig. 3 (c).

If so make syndeton body 42, then in the vertical, insulativity particle 1 is absorbed in coatingparticles 2, through surface (palladium layer) conducting first electrode 5 and second electrode 7 of coatingparticles 2; In the horizontal, insulativity particle 1 keeps insulativity thus between between coatingparticles.

In recent years; The anisotropic conductive caking agent that COG is used requires the insulating reliability under the thin space of 10 μ m levels; If use the related anisotropic conductive caking agent 40 of this embodiment, then can improve the insulating reliability under the thin space of 10 μ m levels.

As the caking agent 3 that in anisotropic conductive caking agent 40, uses, use the mixture of heat reactivity resin and solidifying agent, particularly, the mixture of preferred epoxy and latent curing agent.

As epoxy resin; Can use separately or following compound is used in two or more mixing: derived from the bisphenol-type epoxy resin of epoxy chloropropane and dihydroxyphenyl propane, F, AD etc.; Epoxy-Novolak resin derived from epoxy chloropropane and phenol phenolic varnish or cresols phenolic varnish; Having the naphthalene that contains the naphthalene nucleus skeleton is epoxy resin, and 1 intramolecularly such as glycidyl amine, glycidyl ether, biphenyl, ester ring type has the various epoxy compoundss of plural glycidyl etc.

As these epoxy resin, preferably use foreign ion (Na ⁺, C1 ^-Deng), water-disintegrable chlorine etc. has been reduced to the high purity goods below the 300ppm.Thus, prevent electromigration easily.

As latent curing agent, can enumerate: the salt of imidazoles system, hydrazides system, boron trifluoride-amine complex, sulfonium salt, amine imide, polyamine, Dyhard RU 100 etc.In addition, can use the mixture or the ultraviolet homenergic ray-curable resin of free radical reaction property resin and organo-peroxide in the caking agent.

In order to reduce the stress after bonding, or in order to improve cementability, can be in caking agent 3 mixed butadiene rubber, acrylic rubber, SBR styrene butadiene rubbers, Zylox etc.

In addition, as caking agent 3, can use pasty state or membranaceous caking agent.Membranaceous for caking agent is processed, it is effective cooperating thermoplastic resins such as phenoxy resin, vibrin, polyamide resin.The stress of these film-forming properties polymers during also to the curing of reaction resin relaxes and has effect.The situation that particularly has functional groups such as hydroxyl in order to improve cementability, is more preferably the film-forming properties polymer.

The formation of film can be carried out with being described below: through containing the high molecular adhesive composite of epoxy resin, acrylic rubber, latent curing agent and film-forming properties dissolving or dispersion and aqueousization in organic solvent; On the separability base material, be coated with, below the active temperature of solidifying agent, remove and desolvate.From the deliquescent viewpoint that improves material, as the organic solvent that uses this moment, optimization aromatic hydrocarbon system and the mixed solvent that contains oxygen system.

The thickness of anisotropic conductive caking agent 40, can consider conducting particles 8 particle diameter and anisotropic conductive caking agent 40 characteristic and relatively confirm, be preferably 1～100 μ m.If, then can not obtain sufficient cementability less than 1 μ m, if surpass 100 μ m, then, need a large amount of conducting particless in order to obtain electroconductibility, therefore unrealistic.From these reasons, thickness is more preferably 3～50 μ m.

As first substrate 4 or second substrate 6, can enumerate glass substrate, polyimide etc. and be with the bare chip of shape substrate, driver ICs etc., inflexible base plate for packaging etc.

More than, carried out detailed explanation for the preferred implementation of the method for manufacture of conducting particles involved in the present invention and conducting particles, but the present invention is not limited to above-mentioned embodiment.For example, the related conducting particles 8a of first embodiment can possess other the conductive layer (for example gold layer) on surface of palladium layer 12 and lining palladium layer 12 on the surface of resin particle 11, coated with resin particulate 11.In addition, the related conducting particles 8b of second embodiment can possess the surface of resin particle 11, coated with resin particulate 11 palladium layer 12, lining palladium layer 12 the surface other conductive layer (for example gold layer) and at a plurality of insulativity particles 1 of the surface configuration of conductive layer.

Embodiment

Below, through embodiment the present invention is described.

(coatingparticles 1)

After implementing alkali degreasing, using in the acid with median size is crosslinked polystyrene particle (resin particle) 3g of 3.5 μ m.To being adjusted into pH is that 6.0 cationic macromolecular liquid 100ml adds the aforementioned resin particulate, 60 ℃ stir 1 hour down after, using the aperture is that the membranous filter (Millipore manufactured) of 3 μ m filters, and washes.To Atotech Neoganth 834 (ア ト テ ッ Network ネ ネ オ ガ Application ト 834) (Atotec Japan (strain) manufacturing that contains as palladium catalyst; Trade(brand)name) the palladium catalyst liquid 100mL of 8 weight % adds the resin particle after washing; After stirring 30 minutes under 35 ℃; Using the aperture is membranous filter (Millipore manufactured) filtration of 3 μ m, washes.Repeat to add resin particle to palladium catalyst liquid, give the palladium catalyst of resin particle surface q.s.Here, " palladium catalyst " is the catalyzer that is used for forming on the resin particle surface palladium layer, is not the palladium layer itself among the present invention.

Then, be the resin particle after the sodium hypophosphite liquid of 6.0 3g/L adds washing to being adjusted into pH, obtain the surface by sensitization resin particle (resin core particle).Then, with the surface by sensitization resin particle be immersed in the zero(ppm) water ultrasonic dispersing.

Using the aperture is the above-mentioned liquid of membranous filter (Millipore manufactured) filtration of 3 μ m; Under 50 ℃ condition; With the surface by sensitization resin particle be immersed in APP (the former pharmaceutical industries of stone (strain) made as no electrolysis palladium plating solution; Trade(brand)name) in, carries out the no electrolysis Pd plating of 20nm on the resin particle surface.For for the APP of no electrolysis palladium plating solution, as principal constituent, the material that known Hypophosporous Acid, 50 and salt, phosphoric acid and the salt thereof etc. that contain as reductive agent contain phosphorus.

Then, using the aperture is membranous filter (Millipore manufactured) filtration of 3 μ m, carries out 3 washings.After 7 hours,, be produced on the coatingparticles 1 that has the thick palladium layer of 20nm on the resin particle 40 ℃ of following vacuum-dryings through pulverizing disaggregation.

(coatingparticles 2)

Replace using above-mentioned no electrolysis palladium plating solution APP not have electrolysis Pd plating; And under 50 ℃ condition, with the surface by sensitization resin particle be immersed among the MELPLATE Pal6700 as no electrolysis palladium plating solution (Meltex Co., Ltd. makes, the goods name); At pH is not have electrolysis palladium plating 8 times; In addition, use the method same, be produced on the coatingparticles 2 that has the thick palladium layer of 40nm on the resin core particle with coatingparticles 1.For for the MELPLATE Pal 6700 of no electrolysis palladium plating solution, as principal constituent, the material that known Hypophosporous Acid, 50 and salt, phosphoric acid and the salt thereof etc. that contain as reductive agent contain phosphorus.

(coatingparticles 3)

(Meltex Co., Ltd. makes at above-mentioned no electrolysis palladium plating solution MELPLATE Pal 6700; The goods name) appends sodium hypophosphite in and use; In addition, use the method same, be produced on the coatingparticles 3 that has the thick palladium layer of 80nm on the resin core particle with coatingparticles 2.

(coatingparticles 4)

Use with coatingparticles 1 same method and give palladium catalyst, with sensitization resin particle be dispersed in 70 ℃ the plating bath of having dissolved Trisodium Citrate 50g/L (in the bath).Then, use the volume pump while and add plating bath a and plating bath b respectively with 10ml/min abreast, resin particle is not had electrolysis palladium plating.As plating bath a, use and mix palladium 20g/L, Trisodium Citrate 50g/L, quadrol 20g/L, and be adjusted into the liquid of pH=6.0.In addition, among the plating bath a, palladium is with the state dissolving of ion or complex compound, and the amount of above-mentioned palladium " 20g/L " is meant the weight scaled value as palladium metal.As plating bath b, use and mix sodium hypophosphite 1.2mol/L, and be adjusted into the liquid of pH=6.0 with sodium hydroxide.Through using atom extinction photometer analytical sampling particle, be adjusted at the thickness of the no electrolysis palladium layer of resin particle surface formation., the thickness of no electrolysis palladium layer stops the interpolation of non-electrolysis plating liquid when reaching 130nm.After adding end, bubble stops to produce by the time, filters and washes.When reaction stopped, pH was 6.0.Be produced on the coatingparticles 4 that has the thick no electrolysis palladium layer of 130nm on the resin core particle through above method.The coatingparticles 4 of gained is gray.

(coatingparticles 5)

Use with coatingparticles 1 same method and give palladium catalyst, with sensitization resin particle be dispersed in 70 ℃ the plating bath of having dissolved Trisodium Citrate 50g/L.Then, use the volume pump while and add plating bath c and plating bath d respectively with 4ml/min abreast, resin particle is not had electrolysis palladium plating.As plating bath c, use and mix palladium 20g/L, Trisodium Citrate 80g/L, quadrol 20g/L, and be adjusted into the liquid of pH=5.0.As plating bath d, use and mix sodium hypophosphite 2.4mol/L, and be adjusted into the liquid of H=5.0 with sodium hydroxide.Through using atom extinction photometer analytical sampling particle, be adjusted at the thickness of the no electrolysis palladium layer of resin particle surface formation., the thickness of no electrolysis palladium layer stops the interpolation of non-electrolysis plating liquid when reaching 80nm.After adding end, bubble stops to produce by the time, filters and washes.When reaction stopped, pH was 4.8.Be produced on the coatingparticles 5 that has the thick no electrolysis palladium layer of 80nm on the resin core particle through above method.The coatingparticles 5 of gained is gray.

(coatingparticles 6)

Use with coatingparticles 1 same method and give palladium catalyst, with sensitization resin particle be dispersed in 70 ℃ the plating bath of having dissolved sodium tartrate 20g/L.Then, use the volume pump while and add plating bath e and plating bath f respectively with 15ml/min abreast, resin particle is added no electrolytic nickel plating.As plating bath e, use the liquid of mixed Ni 224g/L, sodium tartrate 20g/L.As plating bath f, use the liquid that mixes sodium hypophosphite 226g/L, sodium hydroxide 85g/L.Through using atom extinction photometer analytical sampling particle, the thickness of adjustment nickel., the nickel thickness stops the interpolation of non-electrolysis plating liquid when reaching 40nm.After adding end, bubble stops to produce by the time, filters and washes.When reaction stopped, pH was 6.2, and particulate is gray.Then, under 50 ℃ condition, the resin particle behind the no electrolytic nickel plating is immersed among the APP (the former pharmaceutical industries of stone (strain) the manufacturers name of an article) as no electrolysis palladium plating solution, does not have electrolysis palladium plating.

Using the aperture is membranous filter (Millipore manufactured) the filtration aforesaid liquid of 3 μ m, carries out 3 washings.Then, under 40 ℃, carry out 7 hours vacuum-drying, through pulverizing disaggregation, the coatingparticles 6 of the no electrolysis palladium layer of the 40nm of no electrolysis nickel dam that obtain having resin particle thus, the 40nm of coated with resin microparticle surfaces is thick and the no electrolytic nickel laminar surface of lining.

(coatingparticles 7)

Replace no electrolysis palladium plating; With the resin particle that uses the nickel plating that forms with the same method of the situation of coatingparticles 6 be immersed in as the golden plating bath of no electrolysis under 80 ℃ condition to HGS-500 (Hitachi Chemical Co., Ltd.'s manufacturing; The goods name) builds in the liquid of bath; Carry out immersion gold plating, filter and wash.Then, aforementioned particles is immersed in as under 60 ℃ condition, HGS-2000 (Hitachi Chemical Co., Ltd. makes, the goods name) being built in the liquid of bath of no electrolysis gold plating bath, filters and wash.Except that these item, handle through using with coatingparticles 6 same methods, make the coatingparticles 7 of the thick Au layer of the 40nm on thick nickel dam of 40nm with resin particle, coated with resin particulate and lining nickel dam surface.

(insulation-coated processing)

Next, use the coatingparticles 1 ~ 7 of above-mentioned gained to make conducting particles 1 ~ 7.In the insulation-coated processing of the surface adsorption of coatingparticles, use the disclosed method of TOHKEMY 2008-120990 communique to implement as the silicon dioxide microparticle of insulativity particle.In addition; In an embodiment; For the ease of explanation; Do " conducting particles " to the coatingparticles note that possesses the insulativity particle on the surface, do not possess the coatingparticles of insulativity particle on the surface with difference, above-mentioned coatingparticles 1 ~ 5 with after the conducting particles 1 ~ 5 stated all be equivalent to conducting particles involved in the present invention.

(conducting particles 1)

Thiovanic acid 8mmol is dissolved among the methyl alcohol 200mL, makes reaction solution.

Then, to the coatingparticles 1 of above-mentioned reaction solution interpolation lg, use 31 phonomoter and diameter to stir 2 hours down as the stirring rake of 45mm in room temperature (25 ℃).After washed with methanol, using the aperture is membranous filter (Millipore manufactured) the filtration coatingparticles l of 3 μ m, obtains having on the surface coatingparticles l of carboxyl thus.

Then, use ultrapure water diluent molecules amount is 70000 30% polyethyleneimine: amine aqueous solution (making with the pure pharmaceutical worker's industry of light (strain)), obtains 0.3 weight % polyethyleneimine: amine aqueous solution.Aforementioned coatingparticles l with carboxyl to 0.3 weight % polyethyleneimine: amine aqueous solution interpolation 1g at room temperature stirred 15 minutes.

Then, using the aperture is membranous filter (Millipore manufactured) the filtration coatingparticles 1 of 3 μ m, joins among the ultrapure water 200g, at room temperature stirs 5 minutes.The use aperture is that the membranous filter (Millipore manufactured) of 3 μ m further filters coatingparticles l, and the ultrapure water with 200g on the aforementioned films filter carries out 2 cleanings, removes the polymine that is not adsorbed on the coatingparticles l thus.

Then; (mass concentration is 20%, and Japan's chemical industry (strain) is made, goods name: QUARTRON PL-3 as the dispersion liquid of the colloidal silica of insulativity particle with ultrapure water dilution; Median size is 35nm), obtain the silicon-dioxide dispersion soln of 0.1 weight %.Join in the silicon-dioxide dispersion soln of 0.1 weight % with the coatingparticles l after the polymine processing aforementioned, at room temperature stirred 15 minutes.

Next, using the aperture is membranous filter (Millipore manufactured) the filtration coatingparticles l of 3 μ m, joins among the ultrapure water 200g, at room temperature stirs 5 minutes.Further using the aperture is membranous filter (Millipore manufactured) the filtration coatingparticles 1 of 3 μ m, and the ultrapure water with 200g on the aforementioned films filter carries out 2 cleanings, removes the silicon-dioxide that is not adsorbed on the coatingparticles l thus.Then, under 80 ℃, 30 minutes condition, carry out drying, under 120 ℃, carried out heat drying 1 hour, the surface adsorption that is produced on coatingparticles 1 thus has the conducting particles 1 of silicon-dioxide (seed).

(conducting particles 2)

Use coatingparticles 2 to replace coatingparticles 1; (mass concentration is 20%, and Japan's chemical industry (strain) is made, goods name: QUARTRON PL-7 with PL-7; Median size is 75nm) replace PL-3 as colloidal silica dispersion; In addition, use the method same, make conducting particles 2 with conducting particles 1.

(conducting particles 3)

Use coatingparticles 3 to replace coatingparticles 1; (mass concentration is 20%, and Japan's chemical industry (strain) is made, goods name: QUARTRON PL-13 with PL-13; Median size is 130nm) replace PL-3 as colloidal silica dispersion; In addition, use the method same, make conducting particles 3 with conducting particles 1.

(conducting particles 4)

Use coatingparticles 4 to replace coatingparticles 1; (mass concentration is 20%, and Japan's chemical industry (strain) is made, trade(brand)name: QUARTRON PL-20 with PL-20; Median size is 200nm) replace PL-3 as colloidal silica dispersion; In addition, use the method same, make conducting particles 4 with conducting particles 1.

(conducting particles 5)

Use coatingparticles 5 to replace coatingparticles 1; (mass concentration is 20%, and Japan's chemical industry (strain) is made, trade(brand)name: QUARTRON PL-50 with PL-50; Median size is 500nm) replace PL-3 as colloidal silica dispersion; In addition, use the method same, make conducting particles 5 with conducting particles 1.

(conducting particles 6)

Use coatingparticles 6 to replace coatingparticles 3, in addition, use the method same, make conducting particles 6 with conducting particles 3.

(conducting particles 7)

Use coatingparticles 7 to replace coatingparticles 3, in addition, use the method same, make conducting particles 7 with conducting particles 3.

(embodiment 1)

< making of adhesive solution >

With phenoxy resin (Union Carbide manufactured; Trade(brand)name: PKHC) 10g and the acrylic rubber (multipolymer of 40 parts of Bing Xisuandingzhis, 30 parts of ethyl propenoates, 30 parts of vinyl cyanide, 3 parts of SY-Monomer Gs; Molecular weight: 850,000) 7.5g is dissolved in ETHYLE ACETATE 30g, obtains the solution of 30 weight %.

Then, to this solution add the liquid epoxy resin that contains the microcapsule-type latent curing agent (epoxy equivalent (weight) is 185, and the EPOXY of Asahi Chemical Industry (strain) makes, trade(brand)name: 30g NOVACURE HX-3941), stir and process adhesive solution.

The above-mentioned 4g conducting particles of processing 1 is scattered among the ETHYLE ACETATE 10g.

According to conducting particles l is the mode of 37 weight % with respect to caking agent; Above-mentioned particle dispersion is scattered in adhesive solution; With this solution with roll be coated on spacer (siloxane treated polyethylene terephthalate film, thickness is 40 μ m) on, under 90 ℃; Dry 10 minutes, making thickness was the anisotropically conducting adhesive film of 25 μ m.

Then; The anisotropically conducting adhesive film that use makes is made according to following method and is had gold bump (area: 30 μ m * 90 μ m; Spacing is 10 μ m; Highly: 15 μ m, protruding number are 362) chip (1.7mm * 17mm, thickness: 0.5mm) with have the glass substrate (thickness: syndeton body sample 0.7mm) of ITO circuit.

At first, at 80 ℃, 0.98MPa (10kgf/cm ²) under, with the bonding film of anisotropic conductive (2 * 19mm) stick on the glass substrate with ITO circuit after, peel off spacer, the convexity of carrying out chip overlaps with the position of the glass substrate with ITO circuit.Then, under 190 ℃, the condition in 5 seconds, heat, pressurize, formally connect, obtain sample from the chip top.

(embodiment 2)

Use conducting particles 2 to replace conducting particles 1; Number for the per unit area dispersive conducting particles of the bonding film of anisotropic conductive of making among the embodiment 2; The ratio of the conducting particles 2 that adds in the adjustment caking agent is with identical with embodiment 1; In addition, likewise make sample with embodiment 1.

(embodiment 3)

Use conducting particles 3 to replace conducting particles 2, in addition, likewise make sample with embodiment 2.

(embodiment 4)

Use conducting particles 4 to replace conducting particles 2, in addition, likewise make sample with embodiment 2.

(embodiment 5)

Use conducting particles 5 to replace conducting particles 2, in addition, likewise make sample with embodiment 2.

(comparative example 1)

Use conducting particles 6 to replace conducting particles 2, in addition, likewise make sample with embodiment 2.

(comparative example 2)

Use conducting particles 7 to replace conducting particles 2, in addition, likewise make sample with embodiment 2.

(determining film thickness of metal)

Mensuration for each thickness of Pb, Ni, Au; After each particle is dissolved in 50 volume % chloroazotic acid; The use aperture is that resin particle and solid matter are removed in membranous filter (Millipore manufactured) filtration of 3 μ m; After measuring the amount of each metal through atom extinction photometer S4700 (Hitachi Co., Ltd make, goods name), it is carried out the conversion of thickness.

(composition analysis in the plated film)

For the composition analysis in the plated film; After each particle is dissolved in 50 volume % chloroazotic acid; The use aperture is that resin is removed in membranous filter (Millipore manufactured) filtration of 3 μ m; Use ICP (inductively coupled plasma) apparatus for analyzing luminosity P4010 (Hitachi Co., Ltd makes, the goods name).

(the lining rate of seed)

Take the electron micrograph of each conducting particles,, calculate the lining rate of seed (insulativity particle) through analysis image.For electron microscope, use S4700 (Hitachi Co., Ltd makes, the goods name), observing more than 5000 times.

(particle cook test)

With arbitrary sampling lg in conducting particles l～7, be scattered in pure water 50g.Then, sample is put into the pressurized vessel of 60mL, 100 ℃ of held 10 hours.

Then, filter the dispersion solvent of conducting particles, measure each metals ion in the filtrating through the atom extinction photometer with the strainer of 0.2 μ m.Obtain the amount of cooking (ion measurement value) according to following formula.

Several 1

(composition analysis)

Each coatingparticles of implementing before the insulation-coated processing is dispersed on the conduction bands (day new EM manufactured, Cat No7311) that are fixed in sample bench, sample bench is put upside down, rock unnecessary conducting particles is dropped.Then; Use is attached to scanning electron microscope S4700, and (Hitachi Co., Ltd makes; The goods name) EDX analytical equipment: EMAX EX-300 (Horiba Ltd makes, the goods name), analysis, the qualitative conductive layer that is amplified to 30,000 times coatingparticles surface.In addition,, measure 10 each coatingparticles, calculate from its MV for the phosphorus concentration in the palladium.In addition, cut out the thin slice of the conductive layer part of conducting particles with focused ion beam.Use transmission electron microscope HF-2200 (Hitachi Co., Ltd makes, the goods name) in observing thin slice more than 100,000 times, and use the EDX of the NORAN manufactured that is attached to said apparatus to carry out each regional composition analysis of conductive layer.Calculate the concentration of each regional nickel, palladium and phosphorus from the value of gained.

(insulation resistance test and conducting resistance test)

Carry out the insulation resistance test (insulating reliability test) and the conducting resistance test of manufactured samples in EXAMPLE l～5, comparative example l～2.About the bonding film of anisotropic conductive importantly, the insulation resistance between chip electrode is high, and chip electrode/vitreous electricity interpolar conducting resistance (connection resistance) is low.

For 20 samples of the determination of insulation resistance between chip electrode, measure its minimum value.About insulation resistance, the result's before and after the expression biasing test (bias test) (long duration test of under humidity is 60%, 90 ℃, the condition of 20V volts DS, carrying out) minimum value.In addition, 100 hours shown in the table 1, be meant time of biasing test in 300 hours, 500 hours, 1000 hours.

In addition, about chip electrode/vitreous electricity interpolar conducting resistance, measure the MV of 14 samples.For conducting resistance, measured the value after initial value and the moisture absorption oven test (is that 85 ℃, humidity are 80% condition held 1000 hours in temperature).

(result)

The mensuration result of the above embodiments 1 ~ 5 and comparative example 1,2 is shown in table 1.

Table 1

As shown in table 1, for the conducting particles of the embodiment that does not use nickel fully 1 ~ 5, as cook the stripping that has metal shown in the test-results hardly.

Relative therewith, used the comparative example 1,2 of nickel for bottom, it is arbitrary compares with embodiment 1 ~ 5, all has the tendency of nickel stripping.Therefore, in the COG of thin space substrate, do not use nickel safer.

In addition, there is stripping hardly in the palladium as precious metal.Can know that insulating reliability test-results major part exists with ... the stripping quantity of nickel, the embodiment that the stripping of nickel is few demonstrates good result, and the insulating reliability of the comparative example that the stripping of nickel is many is low.

Though palladium is less expensive and practical in precious metal, owing to the conducting particles of using as anisotropic conductive film is compared with the nickel of a large amount of uses, it remains at high price, therefore hopes to reduce as far as possible the usage quantity of palladium.On the other hand, when being connected,, need be trapped in the electrode for the palladium layer that makes the conducting particles surface is not broken with electrode.In addition, with regard to the palladium layer, require can not produce the enough intensity of the degree of breaking or peeling off owing to the external force in the conducting particles production process.Palladium is compared with nickel, is ductile, but difference of hardness.

Among the present invention, in reductive agent, use Hypophosporous Acid, 50, the so phosphate-based no electrolysis palladium plating solution of phosphorous acid,, the conducting particles of hardness height, excellent corrosion resistance can be provided through making phosphorus eutectoid to palladium layer.

(Hitachi Co., Ltd makes through ICP (inductively coupled plasma) apparatus for analyzing luminosity P4010; Trade(brand)name) composition in each plated film of embodiment 1 ~ 5 is carried out qualitative analysis; The result is that palladium and phosphorus are principal constituent, and other elements are not detected in detecting limit of error.

(embodiment 6)

Use coatingparticles 2 to replace using conducting particles 1; Adjust the amount of coatingparticles 2 according to the half the mode of the number that becomes the per unit area dispersive conducting particles of the anisotropic conductive adhesive film of making among the embodiment 1; In addition and embodiment 1 likewise make sample.

(comparative example 3)

Use coatingparticles 7 to replace using conducting particles 1; Adjust the amount of coatingparticles 7 according to the half the mode of the number that becomes the per unit area dispersive conducting particles of the bonding film of anisotropic conductive of making among the embodiment 1; In addition and embodiment 1 likewise make sample.

Use the method same with embodiment 1 ~ 5, carry out in embodiment 6 and the comparative example 3 particle cook test and conducting resistance is tested.

The test-results of embodiment 6 and comparative example 3 is shown in table 2.

Table 2

(not carrying out the evaluation of the particle of insulation-coated processing)

As shown in table 2, the connection resistance of embodiment 6 is good, but the connection resistance of comparative example 3 uprises as time passes.This be because: because the metallic flexible of comparative example 3 (gentle ら な い) therefore is difficult to be absorbed in electrode, the skew that can't follow the trail of the electrode position that causes as time passes.

Use opticmicroscope from glass surface side observation sample, it is many that the result observes in the comparative example 3 aggregation of particles.The coatingparticles 7 of comparative example 3 is carried out EDX analyze, the result thinks: because the phosphorus concentration in the nickel is low to moderate 2 weight %, so in the comparative example 3, produces and result from the gathering of coatingparticles 7 of magnetic.

As shown in table 2, for the embodiment 6 that only possesses the palladium layer as metal level, cook the palladium of a stripping trace in the test, and a large amount of strippings of nickel in the comparative example 3.Result from the poor short circuit of migration because the nickel of stripping causes, or on the palladium surface, form sull, conducting resistance is descended.As stated, should avoid the use of might produce stripping metal (for example: nickel etc.).

As the method that on resin particle, forms the no electrolysis palladium plating of palladium layer; Though use in the present embodiment will be endowed catalyzer, sensitization resin particle be immersed in the method in the no electrolysis palladium plating solution that has carried out building bath; With will be endowed catalyzer, sensitization resin particle be immersed in the zero(ppm) water of heating; Make it to disperse through stirring, add the method for no electrolysis palladium plating solution simultaneously one by one, but the method for palladium plating is not limited to these methods.In addition, the method for adding no electrolysis palladium plating solution one by one for above-mentioned can drip the non-electrolysis plating liquid of having built bath, also can the composition of no electrolysis palladium plating solution be divided into more than at least 2 kinds, and these compositions are added simultaneously and abreast.As the method for the composition of cutting apart no electrolysis palladium plating solution, the method that palladium ion and palladium complex composition and reductive agent composition are added as dividing other liquid is for example arranged.

Industrial applicibility

As above illustrated,, a kind of cheap and excellent conducting particles of high, the interelectrode connection reliability of electroconductibility of migration, cost that can not cause can be provided according to the invention described above.

Nomenclature

1 ... The insulativity particle, 2,2a ... Coatingparticles, 3 ... Caking agent, 4 ... First substrate; 5 ... First electrode, 6 ... Second substrate, 7 ... Second electrode, 8,8a, 8b ... Conducting particles; 11 ... Nuclear particle, 12 ... The palladium layer, 40 ... The anisotropic conductive caking agent, 42 ... The syndeton body.

Claims (19)

1. anisotropic conductive caking agent, it contains caking agent and conducting particles, the conductive layer that said conducting particles possesses resin particle and forms on the surface of said resin particle,

Said conductive layer is the palladium layer that contains phosphorus,

Phosphorus concentration in the said palladium layer is below the above 10 weight % of 1 weight %,

The thickness of said palladium layer is below the above 130nm of 20nm.

2. it is the insulativity particle of 20 ~ 500nm that anisotropic conductive caking agent as claimed in claim 1, said conducting particles possess in the surface configuration of said palladium layer and particle diameter.

3. according to claim 1 or claim 2 anisotropic conductive caking agent, said palladium layer is the palladium layer of reduction plating type.

4. like each described anisotropic conductive caking agent in the claim 1 ~ 3, the composition in the said conductive layer carries out qualitative and quantitative through energy dispersion type X ray optical spectroscopy.

5. like each described anisotropic conductive caking agent in the claim 1 ~ 4, the particle diameter of said resin particle is 1 ~ 10 μ m.

6. anisotropic conductive caking agent as claimed in claim 5, the particle diameter of said resin particle are 1 ~ 5 μ m.

7. anisotropic conductive caking agent as claimed in claim 6, the particle diameter of said resin particle are 2.0 ~ 3.5 μ m.

8. like each described anisotropic conductive caking agent in the claim 1 ~ 7, said resin particle is the resin particle that is made up of vinyl resin, polyolefin resin, PS, divinyl benzene polymers, Vinylstyrene-styrol copolymer or benzoguanamine formaldehyde resin.

9. like each described anisotropic conductive caking agent in the claim 1 ~ 8, the phosphorus concentration in the said palladium layer is below the above 8 weight % of 1 weight %.

10. anisotropic conductive caking agent as claimed in claim 9, the phosphorus concentration in the said palladium layer are below the above 6 weight % of 1 weight %.

11. like each described anisotropic conductive caking agent in the claim 1 ~ 10, the thickness of said palladium layer is below the above 100nm of 20nm.

12. anisotropic conductive caking agent as claimed in claim 11, the thickness of said palladium layer are below the above 80nm of 20nm.

13. like each described anisotropic conductive caking agent in the claim 2 ~ 12, said insulativity particle is an inorganic oxide.

14. anisotropic conductive caking agent as claimed in claim 13, said inorganic oxide are the oxide compounds that contains at least a element of the group that is selected from silicon, aluminium, zirconium, titanium, niobium, zinc, tin, cerium and magnesium composition.

15. like claim 13 or 14 described anisotropic conductive caking agents, the median size of said inorganic oxide is 30 ~ 400nm.

16. anisotropic conductive caking agent as claimed in claim 15, the median size of said inorganic oxide are 40 ~ 350nm.

17. like each described anisotropic conductive caking agent in the claim 1 ~ 16, said caking agent contains epoxy resin and latent curing agent.

18. anisotropic conductive caking agent as claimed in claim 17, said epoxy resin are that to be selected from bisphenol-type epoxy resin, epoxy-Novolak resin, naphthalene be that epoxy resin and 1 intramolecularly have at least a in the epoxy compounds of plural glycidyl.

19. like claim 17 or 18 described anisotropic conductive caking agents, said latent curing agent is that to be selected from imidazoles be that solidifying agent, hydrazides are at least a in salt and the Dyhard RU 100 of solidifying agent, boron trifluoride-amine complex, sulfonium salt, amine imide, polyamine.

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