JP3767333B2 - Anisotropic conductive sheet - Google Patents

Description

【００７５】
〔導電性構造物の作製〕
幅が０.１５ｍｍの銅よりなるリード電極で、リード電極間距離が０．１ｍｍの電極ピッチが０．２５ｍｍピッチである２４０のリード電極が並んだ、回路基板のリード電極域に、上記の組成物を幅１．０ｍｍでリード電極と直交方向に、層厚約０.３ｍｍでスクリーン印刷し、厚み方向に平行磁場を作用させながら１５０℃で１時間加熱して硬化させ、これにより回路基板と一体化した導電性構造物（図７）を作製した。作業はクリーンルーム、クリーンブース等の異物の少ないクリーンな環境ではなく、通常の室内で作業を行った。
【００７６】
〔導電性構造物の評価〕
以上において得られた、実施例１〜３、比較例１〜２の組成物を用いて作製された組成物について評価を行った。
評価方法は、導電性構造物上に共通電極となる金メッキを表面に施した平面基板を儲け、平面基板の上よりロードセルに接続された押圧板により加圧し、個々のリード電極―共通電極間の電気抵抗値を測定した。
更に２５℃３０％ＲＨの条件下で平面基板の上から１Ｈｚの周期で繰り返し加圧を行い１万回加圧後の抵抗値を調べるとともに、異方導電シートと接触した平面基板表面の観察を行った。
【００７７】
評価結果を表２に示す。
【００７８】
【表２】

【００７９】
【発明の効果】
本発明の組成物によれば、熱安定性の高い、帯電防止の性質を持つアルキルスルホン酸金属塩を含むことより静電気の発生が抑制され、製造工程における未硬化状態の組成物層の表面への静電気による異物の付着が抑制される。また高温で硬化された後の導電性構造物の絶縁部分、異方導電性シートの絶縁部分に静電気が生じて帯電することを防止または抑制することができるので、得られた異方導電性シートを用いた検査装置は、異物の付着、張り付きの防止、蓄積された静電気の放電による検査装置、導電構造物、導電性シートの障害の発生を低減でき、高温での繰り返し使用においても帯電防止性能が低下しないので、導電性シートを用いた検査装置の作業性の向上、耐久性の向上が達成され、信頼性が向上する。
【図面の簡単な説明】
【図１】本発明の異方導電性シートの一例における構成を示す説明用断面図である。
【図２】本発明の異方導電性シートを製造するために用いられる金型の一例における構成を示す説明用断面図である。
【図３】図２に示す金型内に、シート成形材料層が形成された状態を示す説明用断面図である。
【図４】シート成形材料層中の導電性粒子が当該シート成形材料層における導電部となる部分に集合した状態を示す説明用断面図である。
【図５】本発明の異方導電性シートが、検査対象である回路装置と検査用回路基板との間に介在された状態を示す説明用断面図である。
【図６】支持体を具えた本発明に係る異方導電性シートの一例における構成を示す説明用断面図である。
【図７】本発明の導電性構造物の一例における構成を示す説明用図面である。
【図８】本発明の導電性構造物の一例における構成を示す説明用断面図である。
【符号の説明】
１ 被検査回路装置 ２ 被検査電極
５ 検査用回路基板 ６ 検査用電極
１０ 異方導電性シート １０Ａ シート成形材料層
１１ 導電部 １１Ａ 導電部となるべき部分
１２ 絶縁部 １５ 支持体
５０ 上型 ５１ 強磁性体基板
５２ 強磁性体層 ５３ 非磁性体層
５４ スペーサー ５５ 下型
５６ 強磁性体基板 ５７ 強磁性体層
５８ 非磁性体層
６０ 回路基板 ６１ リード電極
６２ 導電性構造物[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an anisotropic conductive sheet. More specifically, the present invention relates to an anisotropic conductive sheet having excellent antistatic performance for static electricity.
[0002]
[Prior art]
With recent downsizing and thinning of electronic devices, the necessity for connection between minute circuits, connection between minute parts and minute circuits, etc. has increased dramatically. As the connection method, a solder bonding technique or an anisotropic conductive adhesive is used. In addition, a conductive paste is applied on the circuit board or chip, and the magnetic particles are oriented to move the conductive particles onto the electrodes of the circuit board or chip, and then cured to surround the non-conductive portion on the electrode. There is also a method in which a hardened layer having an electrically conductive portion insulated with is integrally provided and this is connected to an electronic component or a circuit board. (Japanese Patent Laid-Open No. 5-155982)
[0003]
An anisotropic conductive elastomer sheet produced by a method of curing a conductive paste or the like exhibits conductivity only in the thickness direction, or an additive that exhibits conductivity only in the thickness direction when pressed in the thickness direction. It has a pressure-conducting conductive part and can achieve a compact electrical connection without using means such as soldering or mechanical fitting, and absorbs mechanical shocks and strains. Since it has features such as being capable of soft connection, it is possible to use circuit features such as printed circuit boards in the fields of electronic computers, electronic digital watches, electronic cameras, computers, etc. Widely used as a connector for achieving electrical connection with leadless chip carriers, liquid crystal panels, and the like.
[0004]
In electrical inspection of circuit devices such as printed circuit boards and semiconductor integrated circuits, electrodes to be inspected formed on at least one surface of the circuit device to be inspected, and for inspection formed on the surface of the circuit substrate for inspection In order to achieve electrical connection with the electrodes, an anisotropic conductive elastomer sheet is interposed between the inspected electrode region of the circuit device and the inspecting electrode region of the inspecting circuit board.
[0005]
Conventionally, such anisotropic conductive elastomer sheets are known in various structures. For example, JP-A-51-93393 discloses that metal particles are uniformly dispersed in an elastomer. An anisotropic conductive elastomer sheet is disclosed, and Japanese Patent Application Laid-Open No. 53-147772 and the like disclose a number of conductive paths extending in the thickness direction by unevenly distributing conductive magnetic particles in the elastomer. An anisotropic conductive elastomer sheet in which a forming portion and an insulating portion that insulates the insulating portion from each other are formed is disclosed. Further, Japanese Patent Application Laid-Open No. 61-250906 discloses that the surface of the conductive path forming portion is insulated. An anisotropic conductive elastomer sheet in which a step is formed between the two is disclosed.
[0006]
[Problems to be solved by the invention]
However, the anisotropic conductive sheet has conductivity in the thickness direction, but has insulating properties in the plane direction, so depending on the method of use and usage environment, the anisotropic conductive sheet Static electricity is generated on the surface and charged, causing various problems.
For example, when an anisotropic conductive sheet is used for electrical inspection of a circuit device, if the static electricity is generated on the surface of the anisotropic conductive sheet and charged, the anisotropic conductive sheet is subject to inspection by the attractive force due to the static electricity. Since a certain circuit device sticks, it becomes difficult to perform the inspection work smoothly. Also, if high voltage static electricity is accumulated on the surface of the anisotropic conductive sheet, it is inconvenient in terms of ensuring the safety of the worker. Especially when extremely high voltage static electricity is accumulated, the static electricity By discharging, a failure may occur in the inspection device, the anisotropic conductive sheet, or the circuit device to be inspected.
For this reason, in the electrical inspection of circuit devices, the inspection work is interrupted regularly or when static electricity is observed on the surface of the anisotropic conductive sheet, and a static elimination brush, etc. There is a problem that it is necessary to carry out static elimination work on the anisotropic conductive sheet using the, so that the inspection efficiency is lowered. In addition, a burn-in test for testing an object to be inspected under a high temperature condition is performed as an electrical inspection, and high heat resistance is required for the anisotropic conductive sheet.
[0007]
In addition, a conductive paste is applied on the circuit board or chip, and the magnetic particles are oriented to move the conductive particles onto the circuit board or chip electrode, and then cured to remove the surroundings on the electrode. In the method of integrally providing a hardened layer with a conductive part insulated by a conductive part and connecting it to an electronic component or circuit board, if static electricity is generated and charged, foreign matter adheres to the hardened layer due to the static electricity. As a result, there is a problem that the connection with the electronic component or the circuit board is disturbed.
[0008]
The present invention has been made based on the above circumstances, and an object thereof is to provide an anisotropic conductive sheet excellent in heat resistance, which can prevent or suppress electrostatic charge on the surface. There is.
[0009]
[Means for Solving the Problems]
The anisotropic conductive sheet of the present invention isLiquid silicone rubber,Conductive particlesConsisting of metal salts of alkylsulfonic acidManufactured by curing the compositionIt is characterized by that.
[0011]
[Action]
According to the above configuration, since the composition contains an alkylsulfonic acid metal salt having antistatic properties and high heat stability, the surface of the uncured composition layer in the production process was cured at a high temperature. It is possible to prevent or suppress the occurrence of static electricity and charging in the insulating portion of the subsequent conductive structure and the insulating portion of the anisotropic conductive sheet. In addition, due to the excellent thermal stability of the alkyl sulfonic acid metal salt, the anisotropic conductive sheet has little decrease in antistatic ability even in repeated inspection under high temperature conditions such as burn-in inspection. Therefore, the workability of the inspection apparatus using the anisotropic conductive sheet is improved, the occurrence of connection failure is reduced, and the reliability is improved.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the anisotropic conductive elastomer sheet of the present invention will be described with reference to the drawings as appropriate.
[0013]
Of the present inventionThe composition used for the production of the anisotropic conductive sheet is:Below (A) ~(C)Contains ingredientsThe component (C) is 0.1 to 20 parts by weight with respect to 100 parts by weight of the component (A).It is a composition.
(A)Liquid silicone rubber(B)Conductive particles(C) Metal salt of alkyl sulfonic acid
[0019]
Of component (A)Liquid silicone rubber has a viscosity of 10^-110 in sec⁵ Poise or less is preferable, and any of a condensation type, an addition type, a vinyl group or a hydroxyl group-containing one may be used. Specific examples include dimethyl silicone raw rubber, methyl vinyl silicone raw rubber, methyl phenyl vinyl silicone raw rubber, and the like.
[0020]
Liquid silicone rubber containing vinyl groups (vinyl group-containing polydimethylsiloxane) is usually subjected to hydrolysis and condensation reaction of dimethyldichlorosilane or dimethyldialkoxysilane in the presence of dimethylvinylchlorosilane or dimethylvinylalkoxysilane, For example, it can be obtained by subsequent fractionation by repeated dissolution-precipitation.
In addition, the liquid silicone rubber containing vinyl groups at both ends is obtained by anionic polymerization of a cyclic siloxane such as octamethylcyclotetrasiloxane in the presence of a catalyst, using, for example, dimethyldivinylsiloxane as a polymerization terminator, and other reaction conditions. It can be obtained by appropriately selecting (for example, the amount of cyclic siloxane and the amount of polymerization terminator). Here, as the catalyst for anionic polymerization, alkali such as tetramethylammonium hydroxide and n-butylphosphonium hydroxide or silanolate solution thereof can be used, and the reaction temperature is, for example, 80 to 130 ° C.
Such a vinyl group-containing polydimethylsiloxane preferably has a molecular weight Mw (referred to as a standard polystyrene equivalent weight average molecular weight; the same shall apply hereinafter) having a molecular weight of 10,000 to 40,000. Further, from the viewpoint of heat resistance of the obtained conductive path element, the molecular weight distribution index (the value of the ratio Mw / Mn between the standard polystyrene equivalent weight average molecular weight Mw and the standard polystyrene equivalent number average molecular weight Mn. The same shall apply hereinafter) is 2. The following are preferred.
[0021]
On the other hand, a liquid silicone rubber containing hydroxyl groups (hydroxyl group-containing polydimethylsiloxane) usually undergoes hydrolysis and condensation reaction of dimethyldichlorosilane or dimethyldialkoxysilane in the presence of dimethylhydrochlorosilane or dimethylhydroalkoxysilane. For example, and fractionation by repeated dissolution-precipitation.
In addition, cyclic siloxane is anionically polymerized in the presence of a catalyst, and dimethylhydrochlorosilane, methyldihydrochlorosilane, dimethylhydroalkoxysilane or the like is used as a polymerization terminator, and other reaction conditions (for example, the amount of cyclic siloxane and polymerization termination). It can also be obtained by appropriately selecting the amount of the agent. Here, as the catalyst for anionic polymerization, alkali such as tetramethylammonium hydroxide and n-butylphosphonium hydroxide or silanolate solution thereof can be used, and the reaction temperature is, for example, 80 to 130 ° C.
Such a hydroxyl group-containing polydimethylsiloxane preferably has a molecular weight Mw of 10,000 to 40,000. Moreover, since the outstanding heat resistance is acquired, a molecular weight distribution index | exponent of 2 or less is preferable.
[0022]
In the present inventionLiquid silicone rubberIn, any one of the above-mentioned vinyl group-containing polydimethylsiloxane and hydroxyl group-containing polydimethylsiloxane can be used, or both can be used in combination.
[0023]
(2) Conductive particles
(B) As long as it is what is conventionally used in the electrically conductive paste and the electrically conductive sheet as the electrically conductive particle which has the electroconductivity of the component, the kind in particular will not be limited, but by making a magnetic field act From the viewpoint of easily aligning the anisotropic conductive sheet main body in the thickness direction, it is preferable to use conductive particles exhibiting magnetism. Specific examples of such conductive particles include metal particles exhibiting magnetism such as nickel, iron and cobalt, particles of these alloys, particles containing these metals, or these particles as core particles. The core particles are formed by plating the surface of the core particles with a metal having good conductivity such as gold, silver, palladium, rhodium, or non-magnetic metal particles or inorganic particles such as glass beads or polymer particles. Examples include those obtained by plating the surface of particles with a conductive magnetic material such as nickel or cobalt, or those in which core particles are coated with both a conductive magnetic material and a metal having good conductivity. Among these, it is preferable to use nickel particles as core particles and the surfaces thereof plated with a metal having good conductivity such as gold. The means for coating the surface of the core particles with the conductive metal is not particularly limited, and can be performed by, for example, chemical plating or electrolytic plating.
[0024]
When using conductive particles whose core particles are coated with a conductive metal, from the viewpoint of obtaining good conductivity, the conductive metal coverage on the particle surface (relative to the surface area of the core particles). The ratio of the conductive metal coating area) is preferably 40% or more, more preferably 45% or more, and particularly preferably 47 to 95%.
Further, the coating amount of the conductive metal is preferably 0.5 to 50% by mass of the core particles, more preferably 1 to 30% by mass, further preferably 3 to 25% by mass, and particularly preferably 4 to 20%. % By mass. When the conductive metal to be coated is gold, the coating amount is preferably 2 to 30% by mass of the core particle, more preferably 3 to 30% by mass, and further preferably 3.5 to 25%. % By mass, particularly preferably 4 to 20% by mass. When the conductive metal to be coated is silver, the coating amount is preferably 3 to 50% by mass of the core particles, more preferably 4 to 40% by mass, and further preferably 5 to 30%. % By mass, particularly preferably 6 to 20% by mass.
[0025]
Moreover, it is preferable that the particle diameter of electroconductive particle is 1-1000 micrometers, More preferably, it is 2-500 micrometers, More preferably, it is 5-300 micrometers, Most preferably, it is 10-200 micrometers.
Moreover, it is preferable that the particle diameter distribution (Dw / Dn) of electroconductive particle is 1-10, More preferably, it is 1.01-7, More preferably, it is 1.05-5, Most preferably, it is 1.1- 4.
By using conductive particles satisfying such conditions, the conductive structure and conductive sheet obtained can obtain sufficient electrical contact between the conductive particles.
The shape of the conductive particles is not particularly limited, but spherical particles, star-shaped particles, or secondary particles in which these particles are aggregated in that they can be easily dispersed in a polymer. It is preferable that it is a lump shape.
[0026]
The water content of the conductive particles is preferably 5% or less, more preferably 3% or less, still more preferably 2% or less, and particularly preferably 1% or less. By using conductive particles that satisfy such conditions, bubbles are prevented or suppressed from occurring when the composition is cured.
[0027]
Moreover, as the conductive particles, particles whose surfaces are treated with a coupling agent such as a silane coupling agent can be appropriately used. By treating the surface of the conductive particles with a coupling agent, the adhesion between the conductive particles and the elastic polymer is increased. As a result, the obtained conductive sheet has high durability in repeated use. It will be a thing.
The amount of the coupling agent used is appropriately selected within a range that does not affect the conductivity of the conductive particles, but the coupling agent coverage on the surface of the conductive particles (the coupling agent relative to the surface area of the conductive core particles). The ratio of the covering area) is preferably 5% or more, more preferably 7-100%, more preferably 10-100%, particularly preferably 20-100%. .
[0028]
(3) Metal salt of alkyl sulfonic acid
As the metal salt of the alkylsulfonic acid used as the component (C), an alkali metal salt is preferable. Specific examples thereof include sodium 1-decanesulfonate, sodium 1-undecanesulfonate, sodium 1-dodecanesulfonate, sodium 1-tridecanesulfonate, sodium 1-tetradecanesulfonate, sodium 1-pentadecanesulfonate, -Sodium hexadecane sulfonate, sodium 1-heptadecane sulfonate, sodium 1-octadecane sulfonate, sodium 1-nonadecane sulfonate, sodium 1-eicosandecane sulfonate, potassium 1-decane sulfonate, 1-undecane sulfonic acid Potassium, potassium 1-dodecanesulfonate, potassium 1-tridecanesulfonate, potassium 1-tetradecanesulfonate, potassium 1-pentadecanesulfonate, potassium 1-hexadecanesulfonate, 1- Potassium pentadecanesulfonate, potassium 1-octadecanesulfonate, potassium 1-nonadecanesulfonate, potassium 1-eicosandecanesulfonate, lithium 1-decanesulfonate, lithium 1-undecanesulfonate, lithium 1-dodecanesulfonate 1-tridecane sulfonic acid lithium, 1-tetradecane sulfonic acid lithium, 1-pentadecane sulfonic acid lithium, 1-hexadecane sulfonic acid lithium, 1-heptadecane sulfonic acid lithium, 1-octadecane sulfonic acid lithium, 1-nonadecane sulfonic acid Examples thereof include lithium acid, lithium 1-eicosandecasulfonate, and isomers thereof. Of these compounds, sodium salts are particularly preferred because of their excellent heat resistance. These may be used in combination of a plurality of types.
[0029]
Addition amount The addition amount of the metal salt of alkylsulfonic acid is within the range of 0.1 to 20 parts by weight with respect to 100 parts by weight of component (A).Is done.The reason for this is that if the amount of the metal salt of sulfonic acid is less than 0.1% by weight, the antistatic effect of the resulting conductive structure may be lowered, which is not preferable, whereas it exceeds 20% by weight. In some cases, the mechanical strength of the resulting conductive structure is reduced, or the electrical conductivity of the insulating portion between the conductive path is increased, resulting in a decrease in insulation between the conductive path. This is not preferable.
[0031]
As the curing agent for component (D), organic peroxides, fatty acid azo compounds, hydrosilylation catalysts, and the like can be used. Specific examples of the organic peroxide include benzoyl peroxide, bisdicyclobenzoyl peroxide, dicumyl peroxide, and di-tert-butyl peroxide. Specific examples of the fatty acid azo compound include azobisisobutyronitrile. Specific examples of what can be used as a catalyst for the hydrosilylation reaction include chloroplatinic acid and salts thereof, platinum-unsaturated siloxane complex, vinylsiloxane and platinum complex, platinum and 1,3-divinyltetramethyldisiloxane. And the like, a complex of triorganophosphine or phosphite and platinum, an acetyl acetate platinum chelate, a complex of cyclic diene and platinum, and the like.
[0033]
The addition amount of the curing agent is not particularly limited. For example, the addition amount of the curing agent is set to a value within the range of 1 to 30 parts by weight with respect to the compound of component (A). preferable. The reason for this is that if the amount of the curing agent used is less than 1 part by weight, the curability of the compound may be significantly reduced. On the other hand, if the amount of the curing agent used exceeds 30 parts by weight, the reactivity is reduced. This is because it becomes difficult to control and the storage stability in the composition may decrease.
[0034]
(5) Additive
As compounds other than those described above in the composition, solvents, curing accelerators, polymer additives, reactive diluents, polymerization inhibitors, polymerization initiation assistants, leveling agents, wettability improvers, surfactants, plasticizers, Contains one or a combination of two or more UV absorbers, antioxidants, antistatic agents, inorganic fillers, antifungal agents, humidity control agents, dye solubilizers, buffer solutions, chelating agents, flame retardants, etc. Can be made.
[0036]
As a form of the conductive sheet, the conductive particles are unevenly distributed in the elastomer, so that a plurality of conductive path forming portions extending in the thickness direction and insulating portions for insulating them from each other are formed. Examples include anisotropic conductive elastomer sheets, anisotropic conductive elastomer sheets in which a step is formed between the surface of the conductive path forming portion and the insulating portion, and anisotropic conductive elastomer sheets held by a metal frame.The
[0037]
The conductive sheet of the present invention isthe aboveContains (A) to (C) components or (A) to (D) componentsThe component (C) is 0.1 to 20 parts by weight per 100 parts by weight of the component (A).Manufactured by curing the composition.
[0039]
The method of adding the curing agent to the composition is not particularly limited, but it is preferable to preliminarily mix it with a curable compound from the viewpoints of storage stability and prevention of uneven distribution of the catalyst when mixing the components.
It is preferable to use an appropriate amount of the curing agent in consideration of the actual curing speed, balance with the pot life, and the like. Moreover, hydrosilylation reaction control agents, such as an amino group containing siloxane and a hydroxy group containing siloxane, which are usually used for controlling the curing rate and pot life can be used in combination.
[0040]
According to this exampleConductive particlesFrom the viewpoint of easily orienting the particles in the thickness direction of the conductive sheet main body by a method of applying a magnetic force, it is preferable to use conductive magnetic particles.
[0046]
Such conductive particles are preferably contained in the conductive path forming portion at a volume fraction of 20 to 60%, preferably 25 to 40%. When this ratio is less than 20%, a conductive path forming portion having a sufficiently small electric resistance value may not be obtained. On the other hand, when this ratio exceeds 60%, the obtained conductive path forming part tends to be fragile, and the elasticity required for the conductive path forming part may not be obtained.
[0047]
FIG. 1 is a cross-sectional view illustrating the configuration of an example of the anisotropic conductive sheet of the present invention. This anisotropic conductive sheet 10 is contained in an elastic substrate.Conductive particlesIs contained in an oriented state so as to be aligned in the thickness direction of the anisotropic conductive sheet 10,Conductive particlesA conductive path is formed by the chain. In the example shown,Conductive particlesA plurality of columnar conductive portions 11 that are densely packed and extend in the thickness direction, and insulate these conductive portions 11 from each other.Conductive particlesThe conductive portion 11 is arranged along the surface direction according to a pattern corresponding to the pattern of the electrode to be inspected, for example, the electrode to be inspected of the circuit device to be inspected. The insulating portion 12 is formed so as to surround each of the conductive portions 11. In this example, the conductive portion 11 is formed so as to protrude from the surface of the insulating portion 12.
[0048]
In the above, the thickness of the insulating part 12 of the anisotropic conductive sheet 10 is preferably 0.1 to 2 mm, particularly preferably 0.2 to 1 mm.
Moreover, it is preferable that the protrusion height from the surface of the insulation part 12 in the electroconductive part 11 is 0.5 to 100% of the thickness of the insulation part 12, More preferably, it is 1 to 80%, Most preferably, it is 5 to 50. %. Specifically, the protrusion height is preferably 0.01 to 0.3 mm, more preferably 0.02 to 0.2 mm, and particularly preferably 0.03 to 0.1 mm.
Moreover, it is preferable that the diameter of the electroconductive part 11 is 0.05-1 mm, especially 0.1-0.5 mm.
[0049]
The conductive part 11 preferably contains conductive particles in a volume fraction of 5 to 60%, preferably 8 to 50%, particularly preferably 10 to 40%. When this ratio is less than 5%, the conductive part 11 having a sufficiently small electric resistance value may not be obtained. On the other hand, when this ratio exceeds 60%, the obtained conductive part 11 tends to be fragile, and the elasticity necessary for the conductive part may not be obtained. Moreover, the electrical resistance in the thickness direction of the conductive portion 11 is 100 mΩ or less in a state where the conductive portion 11 is pressurized with a load of 10 to 20 gf in the thickness direction..The electrical conductivity of the insulating part 12 is 10^-14S / cm-10^-7S / cm.Electrical conductivity is 10^-14If it is S / cm or more, the conductive structure is preferable because it exhibits antistatic performance of static electricity. On the other hand, the electrical conductivity is 10^-7If it is S / cm or less, the insulation between the conductive paths is not lowered, which is preferable.
[0050]
Such an anisotropic conductive sheet 10 can be manufactured as follows, for example.
FIG. 2 is a cross-sectional view illustrating the configuration of an example of a mold used for manufacturing the anisotropic conductive sheet 10 of the present invention. The mold is configured such that an upper mold 50 and a lower mold 55 that is paired with the upper mold 50 are arranged so as to face each other with a frame-shaped spacer 54 interposed between the lower surface of the upper mold 50 and the upper surface of the lower mold 55. A cavity is formed between them.
In the upper mold 50, a ferromagnetic layer 52 is formed on the lower surface of the ferromagnetic substrate 51 according to a pattern opposite to the arrangement pattern of the conductive portions 11 of the target anisotropic conductive sheet 10. A non-magnetic layer 53 having a thickness larger than that of the ferromagnetic layer 52 is formed at a place other than the layer 52.
On the other hand, in the lower mold 55, a ferromagnetic layer 57 is formed on the upper surface of the ferromagnetic substrate 56 according to the same pattern as the arrangement pattern of the conductive portions 11 of the target anisotropic conductive sheet 10. A nonmagnetic layer 58 having a thickness larger than the thickness of the ferromagnetic layer 57 is formed at a place other than the body layer 57.
[0051]
Ferromagnetic metals such as iron, iron-nickel alloy, iron-cobalt alloy, nickel, and cobalt can be used as materials constituting the ferromagnetic substrates 51 and 56 in each of the upper mold 50 and the lower mold 55. The ferromagnetic substrates 51 and 56 preferably have a thickness of 0.1 to 50 mm, have a smooth surface, are chemically degreased, and are mechanically polished. preferable.
[0052]
In addition, as a material constituting the ferromagnetic layers 52 and 57 in each of the upper mold 50 and the lower mold 55, a ferromagnetic metal such as iron, iron-nickel alloy, iron-cobalt alloy, nickel, or cobalt is used. it can. The ferromagnetic substrates 52 and 57 preferably have a thickness of 10 μm or more. When this thickness is less than 10 μm, it becomes difficult to cause a magnetic field having a sufficient strength distribution to act on the composition layer formed in the mold, and as a result, the conductive part in the composition layer Since it becomes difficult to gather the conductive particles at a high density in the portion where the film is to be formed, a sheet having good anisotropic conductivity may not be obtained.
[0053]
In addition, as the material constituting the nonmagnetic layers 53 and 58 in each of the upper mold 50 and the lower mold 55, a nonmagnetic metal such as copper, a heat-resistant polymer substance, or the like can be used. It is preferable to use a polymer material cured by radiation in that the nonmagnetic layers 53 and 58 can be easily formed by the above method. Examples of the material include acrylic dry film resists and epoxy-based materials. A photoresist such as a liquid resist or a polyimide liquid resist can be used.
The thicknesses of the nonmagnetic layers 53 and 58 are set according to the thickness of the ferromagnetic layers 52 and 57 and the protruding height of the conductive portion 11 of the target anisotropic conductive sheet 10.
[0054]
And the anisotropic conductive sheet 10 is manufactured as follows using said metal mold | die.
First, a flowable composition is prepared by mixing a specific curable compound and magnetic conductive particles, and this composition is injected into the mold cavity as shown in FIG. Thus, the composition layer 10A is formed.
Next, by arranging, for example, a pair of electromagnets on the upper surface of the ferromagnetic substrate 51 in the upper mold 50 and the lower surface of the ferromagnetic substrate 56 in the lower mold 55 and operating the electromagnets, a parallel magnetic field having an intensity distribution, That is, a parallel magnetic field having a large strength is applied in the thickness direction of the composition layer 10A between the ferromagnetic part 52 of the upper die 50 and the corresponding ferromagnetic part 57 of the lower die 55. As a result, in the composition layer 10A, as shown in FIG. 4, the conductive particles dispersed in the composition layer 10A include the ferromagnetic portion 52 of the upper mold 50 and the lower mold 55 corresponding thereto. They are gathered in a portion 11A to be a conductive portion located between the ferromagnetic portion 57 and oriented in the thickness direction.
[0055]
In this state, the elastic polymer disposed between the ferromagnetic portion 52 of the upper die 50 and the corresponding ferromagnetic portion 57 of the lower die 55 is obtained by curing the composition layer 10A. An anisotropic conductive sheet 10 having a conductive portion 11 in which conductive particles are closely packed and an insulating portion 12 made of an elastic polymer with no or almost no conductive particles is produced.
[0056]
In the above, the curing treatment of the composition layer 10A can be performed with the parallel magnetic field applied, but can also be performed after the parallel magnetic field is stopped. The intensity of the parallel magnetic field that acts on the composition 10A is preferably 200 to 10,000 gauss on average.
As a means for applying a parallel magnetic field to the composition layer 10A, a permanent magnet can be used instead of an electromagnet. The permanent magnet is preferably made of alnico (Fe—Al—Ni—Co alloy), ferrite, or the like in that a parallel magnetic field strength in the above range can be obtained.
The curing treatment of the composition layer 10A is appropriately selected depending on the material to be used, but is usually performed by heat treatment. The specific heating temperature and heating time are appropriately selected in consideration of the type of addition-type liquid silicone rubber constituting the composition layer 10A, the time required to move the conductive particles, and the like.
[0057]
The anisotropic conductive sheet of the present invention can be suitably used for electrical inspection of circuit devices such as semiconductor integrated circuits. Hereinafter, a case where an electrical inspection of a circuit device is performed using the anisotropic conductive sheet of the present invention will be described.
In the electrical inspection of a circuit device, as shown in FIG. 5, an inspection circuit board 5 having inspection electrodes 6 arranged in a pattern opposite to the inspection target electrodes 2 of the circuit device 1 to be inspected is prepared. Is done. Then, the anisotropic conductive sheet 10 is disposed on the surface of the inspection circuit board 5 so that the conductive portion 11 is positioned on the inspection electrode 6, and the anisotropic conductive sheet 10 is covered on the anisotropic conductive sheet 10. The inspection circuit device 1 is arranged so that the electrode 2 to be inspected is positioned on the conductive portion 11 of the anisotropic conductive sheet 10.
[0058]
Next, for example, by moving the inspection circuit board 5 in a direction approaching the circuit device 1 to be inspected, the anisotropic conductive sheet 10 is pressed by the circuit device 1 to be inspected and the circuit board 5 for inspection. As a result, an electrical connection between the inspection electrode 2 of the circuit device 1 to be inspected and the inspection electrode 6 of the inspection circuit board 5 is achieved.
Thereafter, in order to develop a potential defect in the circuit device 1 to be inspected, the environmental temperature is raised to a predetermined temperature, for example, 150 ° C., and in this state, a required electrical inspection is performed on the circuit device 1 to be inspected.
Then, after the electrical inspection of the circuit device 1 to be inspected is completed, the circuit device 1 to be inspected is replaced with another circuit device to be inspected, and the electrical operation is performed by repeating the above operation for the circuit device to be inspected. Is done.
[0059]
Thus, since the anisotropic conductive sheet 10 of the present invention contains an alkylsulfonic acid metal salt having antistatic properties, the surface of the anisotropic conductive sheet is used when used for electrical inspection of circuit devices. Static electricity is hardly generated due to static electricity, and the attractive force caused by the static electricity reduces the sticking of the circuit device to be inspected on the anisotropic conductive sheet, thereby enabling the inspection work to be performed smoothly. In addition, high-voltage static electricity is not accumulated on the surface of the anisotropic conductive sheet, and the occurrence of a failure in the inspection apparatus, anisotropic conductive sheet or circuit device to be inspected due to the discharge of static electricity is suppressed. The
[0060]
The anisotropic conductive sheet of the present invention is not limited to the above embodiment, and various modifications can be made.
(1) As shown in FIG. 6, the anisotropic conductive sheet 10 with a support whose peripheral portion is supported by a frame-like support 15 can be configured.
Such an anisotropic conductive sheet 10 is a mold for manufacturing an anisotropic conductive sheet, and has a support arrangement space area in which a support 15 can be arranged in a cavity. In this state, the support 15 is arranged in the space area for arranging the support, and in this state, the composition is injected and cured as described above.
[0061]
(2) It is not essential in the present invention that the conductive portion 11 is formed so as to protrude from the surface of the insulating portion 12, and the surface of the anisotropic conductive sheet 10 may be a flat surface.
(3) A so-called dispersed or non-distributed anisotropic conductive sheet, which is contained in the base material in a state where the conductive particles are uniformly distributed in the plane direction, can be formed. A so-called uniform type conductive sheet that is contained in the base material in a state of being uniformly dispersed in the surface direction and the thickness direction can also be constituted.
[0062]
(4) The anisotropic conductive sheet of the present invention may be integrally provided on the surface of the inspection circuit board 5 as shown in FIG. 5, for example.
Such an anisotropic conductive sheet 10 is a mold for manufacturing the anisotropic conductive sheet, and has a board placement space area in which a circuit board for inspection can be placed in a cavity. In this state, the circuit board for inspection is placed in the space area for board placement, and in this state, the composition is injected and cured as described above.
[0063]
【Example】
Examples of the present invention will be specifically described below, but the present invention is not limited to these examples.
In the following examples and comparative examples, “part” means “part by weight”.
[0064]
(Preparation of composition)
<Example 1> A and B liquids of addition type liquid silicone rubber “KE1950-40” manufactured by Shin-Etsu Chemical Co., Ltd. were mixed in an equal ratio (weight conversion), and then prepared rubber composition 100. In this part, 130 parts of conductive particles having an average particle diameter of 40 μm, sodium alkanesulfonate (C_nH_{2n + 1}SO_ThreeAfter adding and mixing 2.5 parts of Na (n = 12 to 20)), the composition is defoamed by reducing the pressure.(I)Was prepared.
[0065]
In the above, the addition-type liquid silicone rubber “KE1950-40” has a viscosity at 23 ° C. of the liquid A and liquid B (measured by a B-type viscometer) of 4800 P and the compression set at 150 ° C. of the cured product ( JIS K 6249) is 20%, durometer A hardness at 23 ° C. (JIS K 6249) is 42, and tear strength (JIS K 6249 crescent type) is 35.6 kgf / cm.
In addition, as the conductive particles, nickel particles (“SF300” manufactured by Shellit) are used as core particles, and the core particles are subjected to electroless gold plating (average coating amount: 6% by weight of the weight of the core particles) Used).
[0066]
<Example 2> A composition similar to Example 1 except that sodium alkanesulfonate was added in an amount of 7.5 parts.( ii )Manufactured.
[0067]
<Example 3> A composition as in Example 1 except that the amount of sodium alkanesulfonate added was 15 parts.( iii )Manufactured.
[0068]
<Comparative Example 1> A composition similar to Example 1 except that sodium alkanesulfonate was not added.( iv )Manufactured.
[0069]
<Comparative Example 3> A composition similar to Example 1 except that the amount of sodium alkanesulfonate added was 25 parts.(V)Manufactured.
[0070]
[Mold for manufacturing anisotropic conductive sheet]
Except for having a support arrangement space region in the cavity, a die for manufacturing an anisotropic conductive sheet was produced under the following conditions basically according to the configuration shown in FIG.
Ferromagnetic substrate: material: iron, thickness: 8mm,
Ferromagnetic material layer: material: nickel, thickness: 0.1 mm, diameter: 0.25 mm, pitch (center-to-center distance): 0.5 mm,
Magnetic layer material: resist, thickness: 0.15 mm,
Spacer thickness: 0.3 mm
[0071]
[Manufacture of anisotropic conductive sheet]
A frame-plate-shaped anisotropic conductive sheet support made of stainless steel having a thickness of 0.2 mm was placed in the space for supporting body placement in the cavity of the mold. Next, each prepared composition was injected into the cavity of the mold, and a defoaming process was performed under reduced pressure, thereby forming a composition layer in the mold.
Then, the composition layer was cured at 120 ° C. for 1 hour while applying a parallel magnetic field of 6000 gauss in the thickness direction by an electromagnet to the composition layer, and further released from the mold. Later, post-cure is performed at 200 ° C. for 4 hours, thereby providing anisotropic support with support having a plurality of conductive portions extending in the thickness direction and insulating portions that insulate these conductive portions from each other. A sheet was produced.
The obtained anisotropic conductive sheet is formed by arranging conductive portions having an outer diameter of 0.25 mm in 16 rows and 16 columns at a pitch of 0.5 mm, and the insulating portion has a thickness of 0.3 mm. The thickness of the conductive part is 0.4 mm, and the conductive part is formed so as to protrude from both surfaces of the insulating part (each protruding height is 0.05 mm). Moreover, the ratio of the electroconductive particle in an electroconductive part was 28% in the volume fraction.
[0072]
[Evaluation of anisotropic conductive sheet]
Using the compositions prepared in Examples 1 to 3 and Comparative Examples 1 and 2, anisotropic conductive sheets were prepared and evaluated by the anisotropic conductive sheet manufacturing method.
The evaluation method is to fix a conductive sheet on a printed circuit board having a 16 × 16 0.25 mm diameter electrode corresponding to each conductive part so that the corresponding conductive part and electrode are aligned, and further to the common A flat substrate with gold plating on the surface serving as an electrode was provided, and pressure was applied from above the flat substrate by a pressing plate connected to the load cell, and the electric resistance value between the electrode and the common electrode (electric resistance value of the conductive portion) was measured.
Furthermore, under the condition of 25 ° C. and 30% RH, pressure is repeatedly applied from the top of the flat substrate at a period of 1 Hz to examine the resistance value after pressing 10,000 times and to observe the surface of the flat substrate in contact with the anisotropic conductive sheet. went.
[0073]
The evaluation results are shown in Table 1.
[0074]
[Table 1]

[0075]
[Production of conductive structure]
A lead electrode made of copper having a width of 0.15 mm, 240 lead electrodes having a distance between the lead electrodes of 0.1 mm and an electrode pitch of 0.25 mm arranged in the lead electrode region of the circuit board, the above composition The object was screen printed with a width of 1.0 mm in a direction perpendicular to the lead electrode and with a layer thickness of about 0.3 mm, and cured by heating at 150 ° C. for 1 hour while applying a parallel magnetic field in the thickness direction. An integrated conductive structure (FIG. 7) was produced. The work was done in a normal room, not in a clean environment with few foreign objects such as a clean room or clean booth.
[0076]
[Evaluation of conductive structures]
The compositions produced using the compositions of Examples 1 to 3 and Comparative Examples 1 and 2 obtained above were evaluated.
In the evaluation method, a flat substrate with a gold-plated surface serving as a common electrode on a conductive structure is spread and pressed by a pressure plate connected to the load cell from above the flat substrate, and between each lead electrode and the common electrode. The electrical resistance value was measured.
Furthermore, under the condition of 25 ° C. and 30% RH, pressure is repeatedly applied from the top of the flat substrate at a period of 1 Hz to examine the resistance value after pressing 10,000 times and to observe the surface of the flat substrate in contact with the anisotropic conductive sheet. went.
[0077]
The evaluation results are shown in Table 2.
[0078]
[Table 2]

[0079]
【The invention's effect】
According to the composition of the present invention, generation of static electricity is suppressed by including an alkylsulfonic acid metal salt having high thermal stability and antistatic properties, and to the surface of the uncured composition layer in the production process. The adhesion of foreign matter due to static electricity is suppressed. In addition, the anisotropically conductive sheet obtained can be prevented or suppressed from being charged due to static electricity generated in the insulating part of the conductive structure after being cured at a high temperature and the insulating part of the anisotropically conductive sheet. The inspection device using the anti-adhesion, sticking prevention, can reduce the occurrence of failure of the inspection device, conductive structure, conductive sheet due to accumulated static electricity discharge, anti-static performance even in repeated use at high temperature Therefore, the workability and durability of the inspection apparatus using the conductive sheet are improved, and the reliability is improved.
[Brief description of the drawings]
FIG. 1 is an explanatory cross-sectional view showing a configuration of an example of an anisotropic conductive sheet of the present invention.
FIG. 2 is an explanatory cross-sectional view showing a configuration of an example of a mold used for manufacturing the anisotropic conductive sheet of the present invention.
3 is an explanatory cross-sectional view showing a state in which a sheet molding material layer is formed in the mold shown in FIG. 2. FIG.
FIG. 4 is an explanatory cross-sectional view showing a state in which conductive particles in a sheet molding material layer are gathered in a portion to be a conductive portion in the sheet molding material layer.
FIG. 5 is an explanatory sectional view showing a state in which the anisotropic conductive sheet of the present invention is interposed between a circuit device to be inspected and a circuit board for inspection.
FIG. 6 is an explanatory cross-sectional view showing a configuration in an example of an anisotropic conductive sheet according to the present invention including a support.
FIG. 7 is an explanatory drawing showing a configuration in an example of a conductive structure of the present invention.
FIG. 8 is an explanatory cross-sectional view showing a configuration in an example of a conductive structure of the present invention.
[Explanation of symbols]
1 Circuit device to be inspected 2 Electrode to be inspected
5 Circuit board for inspection 6 Electrode for inspection
10 Anisotropic conductive sheet 10A Sheet molding material layer
11 Conductive part 11A The part which should become a conductive part
12 Insulation 15 Support
50 Upper mold 51 Ferromagnetic substrate
52 Ferromagnetic layer 53 Nonmagnetic layer
54 Spacer 55 Lower mold
56 Ferromagnetic substrate 57 Ferromagnetic layer
58 Non-magnetic layer
60 Circuit board 61 Lead electrode
62 Conductive structures

Claims (1)

It contains the following components (A) to (C), and is for burn-in inspection produced by curing a composition in which the component (C) is 0.1 to 20 parts by weight with respect to 100 parts by weight of the component (A) . An anisotropic conductive sheet,
(A) Liquid silicone rubber (B) Conductive particles (C) Metal salt of alkyl sulfonic acid The anisotropic conductive sheet is along the surface direction according to the pattern corresponding to the pattern of the electrode to be inspected of the circuit device to be inspected. And a plurality of columnar conductive parts that are arranged in a state in which the conductive particles are aligned in the thickness direction, and the insulating parts that insulate these conductive parts from each other and have no or almost no conductive particles And
The conductive part has an electric resistance value of 100 mΩ or less in a state where the conductive part is pressurized with a load of 10 to 20 gf in the thickness direction.
The anisotropic conductive sheet, wherein the electrical conductivity of the insulating part is 10 ⁻¹⁴ S / cm to 10 ⁻⁷ S / cm.

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