JPH11100444A - Electroconductive sheet in thickness direction and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject sheet capable of collectively and simultaneously connecting plural electrode terminals of semiconductor element or the like in high reliability by arranging terminals comprising conductors on the surface of an insulating sheet comprising a specific polyimide resin. SOLUTION: This sheet is obtained by arranging terminals comprising conductors on the either one surface of an insulating sheet comprising a polyimide resin in which the molar ratio of components constituting the resin is represented by the equation 0.9>=(d+e)/(a+b+c+d+e)<=1.1 wherein (a) mole of silicondiamine of the formula [R1 to R4 are each H or a <=6C monofunctional aliphatic or aromatic hydrocarbon; (k) is an integer of 4-10], (b) mole of a specific diamine and (c) mole of other diamine are used as amine components and (d) mole of a specific tetracarboxylic acid dianhydride and (e) mole of the other acid dianhydride are used as acid components, and the insulating sheet is softened in heat contact bonding to a body to be connected and the conductor is sank, and the conduction of the body to be connected to the opposite face of the insulating sheet is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thickness direction conductive sheet capable of simultaneously and highly reliably electrically and mechanically connecting a plurality of electrode terminals of a semiconductor element and an electric / electronic component at the same time, and a sheet thereof. It relates to a manufacturing method.

[0002]

2. Description of the Related Art With the recent demand for higher functionality and lighter, thinner and smaller electronic equipment, high-density integration and high-density mounting of electronic components have been progressing. Semiconductor packages used in these electronic devices have been reduced in size and number of pins, and mounting substrates for mounting electronic components including the semiconductor packages have also been reduced in size. Further, in order to enhance the storability in electronic devices, a rigid-flex board, in which a rigid board and a flexible board are laminated and integrated and can be bent, has been used as a mounting board.

[0003] With the miniaturization of semiconductor packages,
Since the miniaturization of a package using a conventional lead frame has reached its limit, it has recently been proposed to mount a chip on a circuit board and use a BGA (Ball G
Rid Array) and CSP (Chip Scale)
A new package method of area mounting type such as “Package” has been proposed. In these semiconductor packages, a method of electrically connecting electrodes of a semiconductor chip to terminals of a substrate made of various materials such as plastics and ceramics, which is called a semiconductor package substrate having a function of a lead frame of a conventional semiconductor package. As a wire bonding method or TAB
(Tape Automated Bonding) method and FC (Flip Chip) method are known. Recently, BGA and CSP structures using FC connection method which is advantageous for miniaturization of semiconductor packages have been actively proposed. I have. In this FC connection method, generally, a connection bump is formed in advance on a semiconductor chip electrode, and the bump and the terminal on the substrate are aligned and connected by thermocompression bonding. The formation process is complicated and bump manufacturing costs are high, and it is necessary to fill the gap between the chip and the substrate with a resin called underfill to seal the connection part in order to obtain the moisture resistance reliability of the bump connection part. In addition, there is a problem that a process of filling and curing the underfill resin is required, so that the manufacturing process is complicated and the manufacturing cost is increased. Accordingly, a method of using an anisotropic conductive sheet as a connection material instead of a bump for electrical connection between a semiconductor chip and a substrate has been focused on and studied.

[0004] On the other hand, circuit boards are becoming finer and multi-layered due to the necessity of miniaturization. In particular, finer inter-layer connection circuits in multi-layering are important factors for miniaturization of mounting boards. It has become to. Conventionally known multilayer boards that perform interlayer connection with through vias have limitations on the drill diameter and the wiring design of each layer due to the through vias, which limits the miniaturization of the board. Therefore, recently, a build-up method in which an insulating resin layer is formed on a core substrate, and a circuit and a via are repeatedly formed on the insulating resin layer to obtain a multilayer board by laminating the insulating resin layer has attracted attention and various proposals have been made. With this build-up method, fine holes can be formed by laser method or photolithography method and conductors formed by plating, and fine and independent interlayer connection circuits can be obtained. It is advantageous. However, in this method, since a series of steps of forming one layer is repeated to perform multi-layering, the manufacturing cost increases due to the problem that the number of processing steps increases in proportion to the number of layers and the yield decreases. is there. Therefore, as a method of manufacturing a high-density wiring multilayer board with a reduced manufacturing cost, a method of using an anisotropic conductive sheet as an interlayer connection material and obtaining a multilayer board by laminating this with a double-sided board has been proposed and studied.

In the case of a rigid-flex board, which has recently been widely used as a mounting board, the conventional method of connecting a rigid board and a flexible board by through vias is the same as in the case of interlayer connection of a multilayer board. In this case, the use of an anisotropic conductive sheet as an interlayer connection material has been attempted to achieve high-density wiring and to reduce the size of the substrate.

The use of an anisotropic conductive sheet as an electrical connection material in the thickness direction as described above has been attracting more and more attention as an effective means for reducing the size of semiconductor packages and mounting substrates. Anisotropic conductive sheets have been proposed.

Conventionally, conductive fine particles are dispersed in a thermoplastic or thermosetting resin, and the resin flows during thermocompression bonding, so that the conductive fine particles sandwiched between the connection terminals make the electrical conduction in the thickness direction possible. Anisotropic conductive sheets for obtaining connection are well known, and include a liquid crystal display panel and a TCP (Tape Ca).
RRer Package). The anisotropic conductive sheet having the above structure is characterized in that it can be manufactured by a relatively simple process of dispersing conductive fine particles in a resin. Recently, a small through hole was drilled in a resin film using a drill or laser, and then the inside of the through hole was filled with a conductor by plating or conductive paste printing, and an adhesive layer was formed on the surface of the resin film. There has been proposed an anisotropic conductive sheet having such a structure, in which an adhesive layer flows at the time of thermocompression bonding, a conductor is exposed, and an electrical connection in a thickness direction is obtained by a conductor sandwiched between connection terminals. The anisotropic conductive sheet having the above structure is characterized in that the conductor can be arranged at an arbitrary position in the sheet surface.

[0008]

However, the anisotropic conductive sheet obtained as described above has the following problems. First, in the case of a structure in which conductive fine particles are dispersed in a thermoplastic or thermosetting resin, the terminals are narrow because electrical connection is obtained by the conductive fine particles that are stochastically present between the electrodes and the terminals. As the pitch becomes smaller, it is necessary to disperse the conductive fine particles more and more finely, thereby increasing the density of the fine particles and narrowing the distance between the fine particles, thereby deteriorating the electrical insulation property and the connection area between the fine particles and the terminals. There is a problem that the connection resistance increases due to the decrease. In addition, since the anisotropic conductive sheet having the above-described structure does not allow a connection point to be arbitrarily selected in the sheet plane, when used for interlayer connection of a multilayer board,
Circuits other than the terminals to be connected in advance must be covered with an insulating resin, and only the portion to be conducted must be subjected to pressure.In practice, an anisotropic conductive sheet having the above structure is arranged on the entire surface of the multilayer board. It is difficult to achieve conduction.

Next, a minute through hole is made in the resin film by a drill or a laser, and then the inside of the through hole is filled with a conductor by a method such as plating or conductive paste printing.
Furthermore, in the case of a structure in which an adhesive layer is formed on the surface of a resin film, as the terminals become narrower, fine drilling with high positional accuracy is required, and laser drilling becomes the mainstream. Lasers have problems such as low processing speed, low productivity, and high running cost. In addition, the formation of a conductor in a minute hole is generally performed by plating. However, as the hole diameter becomes smaller, uniform plating is more difficult, the height of the conductor tends to vary, and electrical connection cannot be performed at the time of terminal connection. Quality degradation.
Further, the number of processing steps is large and the cost is high.

Accordingly, the present invention has been made as a result of intensive studies in view of the above-mentioned problems of the conventional anisotropic conductive sheet, and has been developed for the connection between a semiconductor chip and a substrate and the interlayer connection of a multilayer board. Uses electrical and mechanical connection in the thickness direction to ensure reliable electrical connection even when the terminal pitch is reduced and also has electrical insulation between adjacent terminals, ensuring high reliability after processing It is an object of the present invention to provide a thickness direction conductive sheet which can be held at a low processing cost.

[0011]

In order to achieve the above object, in the thickness direction conductive sheet of the present invention, a mole of silicon diamine represented by the formula (1), 2,2-bis @ 4-
(4-aminophenoxy) phenyl} propane, 2,2
-Bis {4- (4-aminophenoxy) phenyl} hexafluoropropane, bis {4- (4-aminophenoxy) phenyl} ether, 1,3-bis (3-aminophenoxy) benzene, 1,4-bis ( 3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy)
Benzene, 3,4′-diaminodiphenyl ether,
2,5-diamino-p-xylene, 1,3-bis (3-
(Aminopropyl) -1,1,3,3-tetramethyldisiloxane, one or more diamines b mol and other diamines c mol are selected as amine components.
4,4′-oxydiphthalic dianhydride, 3,3 ′, 4
4'-biphenyltetracarboxylic dianhydride, 3,
One or more kinds of tetracarboxylic dianhydride cmol selected from the group of 3 ′, 4,4′-benzophenonetetracarboxylic dianhydride are used as an acid component, and 0.1 ≦
a / (a + b + c) ≦ 0.5, 0.05 ≦ b / (a + b
+ C) ≦ 0.5, 0.9 ≦ c / (a + b + c) ≦ 1.1
Terminals made of conductors are arranged on the surface of an insulating sheet substantially made of a polyimide resin reacted at a ratio of, and the insulating sheet is softened at the time of heating and compression bonding with a connected body. Is sunk into the inside of the insulating sheet until it reaches the opposite surface, whereby electrical conduction with the opposite surface of the insulating sheet is obtained and at the same time mechanical bonding with the connected object is performed.

[0012]

Embedded image (Wherein R ₁ , R ₂ , R ₃ , and R ₄ are a hydrogen atom or a monovalent aliphatic or aromatic hydrocarbon group having 6 or less carbon atoms, and R ₅ and R ₆ are a divalent group having 1 to 6 carbon atoms. An aliphatic or aromatic hydrocarbon group of k
(Integer between 4 and 10)

[0013]

FIG. 1 is an example of a sectional view of a thickness direction conductive sheet of the present invention. FIG. 1 shows a cross-sectional structure of a thickness direction conductive sheet before performing heat compression bonding with a connected body. In FIG. 1, terminals made of a conductor are arranged on one surface of an insulating sheet. When the resin constituting the insulating sheet is softened at the time of thermocompression bonding with the connected body, the terminals formed of conductors arranged on the surface sink into the insulating sheet and extend to the opposite surface of the insulating sheet. By reaching, it is possible to make the front and back conductive.
At the time of thermocompression bonding with the connected body, the terminals arranged on the surface of the insulating sheet and the electric terminals of the connected body are aligned and crimped. By the thermocompression bonding, the terminals are electrically connected, and at the same time, the connection between the surface of the connected body without the electric terminals and the insulating sheet is performed.

The objects to be connected by the conductive sheet in the thickness direction of the present invention include a semiconductor element and a lead frame, a semiconductor element and a substrate, a semiconductor package and a mounting substrate, and chip parts used for surface mounting. Mounting board,
It can be widely used for devices that make electrical connections in the thickness direction, such as mounting substrates and mounting substrates, mounting substrates and flexible substrates, but because of the fine connection, electrical connection between the semiconductor element and the substrate It is particularly useful when used.

The conductor terminals of the conductive sheet in the thickness direction of the present invention may be arranged unevenly on only one surface of the insulating sheet as shown in FIG. 1, or may be arranged on both sides of the insulating sheet as shown in FIG. May be arranged so as to face the surface. In the case of the structure shown in FIG. 2, since the conductor terminals sink from both sides of the insulating sheet at the time of thermocompression bonding, if the height of the conductor terminals is half the thickness of the insulating sheet, the conduction between the front and back sides is reduced. Can be obtained. In such a configuration, it is necessary to precisely match the positions of the conductor terminals arranged on the front and back, but the height of the conductor terminals may be lower than when arranged on one side, so that the formation of the conductor terminals is easy. become. FIG. 3 shows an example in which the conductor terminals of the present invention are arranged on both sides of an insulating sheet so as not to face each other. In the case of the structure shown in FIG. 3, the distance between the conductor terminals for connection can be made wider than when all the connection terminals are arranged on one side of the insulating sheet, so that a narrower pitch of the connected terminals can be accommodated. it can.

Various characteristics are required for the insulating sheet in the thickness direction conductive sheet of the present invention. Not only high electrical insulation but also mechanical properties such as self-holding property and flexibility for holding handling of the sheet after processing the conductor terminal are required. Also, at the time of thermocompression bonding, the material constituting the connected body does not deteriorate, and the workability at low temperature and short time enables mass production in a short time. In this case, the conductor terminals move inside the sheet to the opposite side. It is necessary to have thermoplasticity as much as possible and a thermal elastic modulus so as not to move the conductor terminals in the plane direction of the sheet. After heat-press bonding, adhesion to the connected object, heat resistance that does not cause decomposition gas generation due to heat during further circuit joining, reliability such as low water absorption to prevent migration of conductive metal after processing, etc. Is required. In the present invention, it has been found that all of these properties can be satisfied by mainly including a polyimide resin having a structure defined in the claims as an essential component.

The polyimide resin forming the insulating sheet is characterized by containing a silicone component. This is because the polyimide structure realizes mechanical properties such as high heat resistance and flexibility, and the silicone structure in the molecule also realizes excellent properties such as workability at low temperature and short time, low water absorption and adhesion. There is a feature.

The silicone diamine represented by the formula (1) used in the present invention is α, ω-bis (3-aminopropyl) polydimethylsiloxane, etc., where k = 4-1.
5 is preferred, and a value of k in the range of 5 to 10 is particularly preferred in terms of glass transition temperature, adhesiveness, and heat resistance. When k is 3 or less, a high temperature or a long time is required for the bonding step. Conversely, when k is 16 or more, the compatibility of the silicone portion is reduced, and the properties of the entire sheet are reduced.

In the present invention, 2,2-bis (4- (4-aminophenoxy) phenyl) propane, 2,2-bis
{4- (4-aminophenoxy) phenyl} hexafluoropropane, bis {4- (4-aminophenoxy) phenyl} ether, 1,3-bis (3-aminophenoxy) benzene, 1,4-bis (3- Aminophenoxy)
Benzene, 1,4-bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 3,4′-diaminodiphenyl ether, 2,5-
One or more diamines selected from diamino-p-xylene and 1,3-bis (3-aminopropyl) -1,1,3,3-tetramethyldisiloxane are also used. In the present invention, a diamine having another structure can be used in combination as long as the intended properties are not impaired. The content ratio of these diamines is 0.1 ≦ a /
(A + b + c) ≦ 0.5 and 0.5 ≦ b / (a + b +
c) Must be ≦ 0.9. a / (a + b + c)
If is less than 0.1, workability at low temperature and short time is not exhibited, and if it is more than 0.5, heat resistance and mechanical properties of the insulating sheet when heated are deteriorated. On the other hand, b / (a +
When (b + c) is less than 0.5, the sheet formability in a solution state is reduced.

The tetracarboxylic dianhydride used in the present invention comprises 4,4'-oxydiphthalic dianhydride, 3,3 Either ', 4,4'-biphenyltetracarboxylic dianhydride or 3,3', 4,4'-benzophenonetetracarboxylic dianhydride as an essential component, alone or in combination of two or more. Must be used. Among them, 4,4′-oxydiphthalic dianhydride alone, or 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride 50 to 9 respectively
It is desirable to use a combination of 0 mol% and 50 to 10 mol%. Further, an acid dianhydride having another structure can be used in combination with less than 20 mol% of the whole as long as the intended properties are not impaired.

The constituent molar ratio of these diamine and acid is 0.1.
9 ≦ (d + e) / (a + b + c + d + e) ≦ 1.1. More preferably, 0.975 ≦ d (d
+ E) / (a + b + c + d + e) ≦ 1.025. (D + e) / (a + b + c + d +
When e) is less than 0.9, the adhesive strength becomes weak because the molecular weight is low and brittle. On the other hand, when the ratio exceeds 1.1, unreacted carboxylic acid is undesirably decarbonated during heating, causing gas generation and foaming.

The reaction between the tetracarboxylic dianhydride and the diamine is carried out by a known method in an aprotic polar solvent. Aprotic polar solvents include N, N-dimethylformamide (DMF), N, N-dimethylacetamide (D
MAC), N-methyl-2-pyrrolidone (NMP), γ
-Butyrolactone, tetrahydrofuran (THF), diglyme, cyclohexanone, 1,4-dioxane (1,4-DO) and the like. As the aprotic polar solvent, only one kind may be used, or two or more kinds may be used as a mixture. At this time, a non-polar solvent compatible with the aprotic polar solvent may be mixed and used. Aromatic hydrocarbons such as toluene, xylene, and solvent naphtha are often used. The proportion of the non-polar solvent in the mixed solvent is preferably 40% by weight or less. This is because if the amount of the nonpolar solvent is 40% by weight or more, the dissolving power of the solvent may be reduced and polyamic acid may be precipitated. The reaction between the tetracarboxylic dianhydride and the diamine is carried out by dissolving the well-dried diamine component in the above-mentioned reaction solvent that has been dehydrated and purified, and adding thereto the ring-closing rate of 98%, more preferably 99% or more. The reaction is allowed to proceed by adding the anhydride.

The polyamic acid solution thus obtained is
Subsequently, it can be dehydrated and cyclized by heating in an organic solvent to obtain a polyimide. Since water generated by the imidation reaction interferes with the ring closure reaction, an organic solvent that is incompatible with water is added to the system and azeotroped to form Dean-Stark (Dea-Stark).
Discharge out of the system using a device such as an n-Stark tube. Dichlorobenzene is known as an organic solvent that is not compatible with water, but the above-mentioned aromatic hydrocarbon is preferably used for electronics because a chlorine component may be mixed therein. Further, it does not prevent the use of compounds such as acetic anhydride, β-picoline, and pyridine as a catalyst for the imidization reaction.

In the present invention, the higher the degree of imide ring closure, the better the degree of imidization. If the rate of imidization is low, imidization occurs due to heat during use to generate water, which is not preferable. Therefore, 95% or more, more preferably 98% or more. Is preferably achieved. In the present invention, processing can be performed using the obtained polyimide solution. Further, the polyimide solution may be poured into a poor solvent to reprecipitate the polyimide resin, remove unreacted monomers, purify, and dry to use as a solid polyimide resin. In addition, a coloring agent, an inorganic filler, various coupling agents, and the like may be added to these polyimides as long as their properties are not impaired.

As a method of forming the conductor terminal, a method of casting the above-mentioned polyamic acid solution or polyimide solution on a metal foil and then drying and forming the film to form a metal foil of a constituent is etched. The polyamic acid solution above,
Alternatively, a method of forming a mask on the surface of an insulating sheet made of a polyimide solution by plating, laminating an insulating sheet and a metal foil in advance,
A method of forming the metal foil by etching can be used. When using a polyamic acid solution,
The polyimide sheet can be obtained by heating after the solution casting to cause thermal imidization of the amic acid together with the evaporation of the solvent, so that the step of heat imidization in a solution state is unnecessary. However, since the imidization of amic acid actually occurs at a temperature higher than the boiling point of the solvent used, heating at a high temperature is required. For this reason, there are also disadvantages such as the necessity of a drying apparatus capable of withstanding high temperatures and the possibility that the adhesive property at the time of thermocompression bonding may be reduced due to the high heat history applied to the obtained polyimide resin. Therefore, it is desirable to use a polyimide solution in order to obtain high characteristics. One of the methods of using the polyimide solution is to re-dissolve the re-precipitated solid polyimide resin in a solvent having a low boiling point, and further reduce the drying temperature and the heat history of the polyimide resin. Usually, a rolled copper foil or an electrolytic copper foil is used as the metal foil, but the metal foil is not limited to these. The conductor terminals may be arranged in a lattice at an arbitrary pitch, or may be arranged so as to correspond to the terminals of the connected body,
It can be selected according to the purpose. The height of the conductor terminal is 0.7 to 1.5 times the thickness of the insulating sheet to be used.
Double height is preferred. When the height is lower than 0.7 times the insulating sheet, the conductor terminals do not reach the back surface of the insulating sheet during the heat-press bonding, and the conduction between the front and back cannot be obtained. On the other hand, if it is higher than 1.5 times, the conductor terminal becomes a pillar when heat-pressed, a gap is formed between the connected body and the insulating sheet, and the sheet cannot be bonded, and the electrical reliability is reduced. A second conductor layer may be formed on the surface of the conductor terminal for the purpose of further improving electrical connection. For example, electrolytic plating or electroless plating is used as the method, and a metal such as gold, tin, lead, or indium can be used for the conductor.

In the method of connecting the object to be connected using the thickness direction conductive sheet of the present invention, first, the conductor terminal of the thickness direction conductive sheet of the present invention and the terminal of the object to be connected are aligned and overlapped. Then, the conductor terminals are sunk into the insulating sheet by heat and pressure bonding. Then, at the same time that the conductor terminal penetrates the insulating sheet, the terminal of the connected body and the conductor terminal are joined by thermocompression bonding, and the insulating sheet and the connected body are bonded. The temperature at the time of thermocompression bonding is set so that the conductor sheet formed on the surface of the insulating sheet is sufficiently softened and sinks into the inside of the insulating sheet by the pressure at the time of crimping. This temperature varies depending on the type and abundance of the acid dianhydride and the diamine of the polyimide used for the insulating sheet.
It can be performed at 00 ° C.

[0027]

【Example】

(Example 1) N-methyl-2-pyrrolidone (NMP) 2
68.2 g is vigorously stirred for 10 minutes while flowing nitrogen gas. Next, 78.9318 g (0.0270 mol) of 1,3-bis (3-aminophenoxy) benzene and 2,2
-Bis (4- (4-aminophenoxy) phenyl) propane 15.5994 g (0.0380 mol) and α, ω-
Bis (3-aminopropyl) polydimethylsiloxane 2
Charge 9.2950 g (average molecular weight 837, 0.0350 mol), heat the system to 60 ° C. and stir until uniform. After dissolving uniformly, the system was cooled to 5 ° C in an ice water bath,
4,4'-oxydiphthalic dianhydride 31.0222 g
(0.1000 mol) was added over 10 minutes while keeping the powdery state, and then stirring was continued for 5 hours. During this time the flask is 5
C. After that, remove the nitrogen gas inlet tube and cooler,
A Dean-Stark tube filled with xylene was attached to the flask, and 67.1 g of xylene was added to the polyamic acid solution formed in the system. The system was heated by replacing the ice water bath with an oil bath, and the generated water was removed from the system. After heating for 4 hours, no water was generated from the system. The polyimide resin solution I obtained after cooling was cast on a rolled copper foil having a thickness of 18 μm by a reverse roll coater and then dried.
A 5 μm thick insulating layer sheet was formed to obtain a polyimide sheet with a copper foil. Drying temperature up to 200 ° C and drying time 1
5 minutes. A semiconductor element having electrodes for external connection on the periphery of the circuit surface as an adherend and a substrate having connection terminals at positions corresponding to the electrodes of the semiconductor element were prepared. The flexibility of laminating a dry film resist on the copper foil surface of the polyimide sheet with the copper foil and forming conductor terminals at positions corresponding to the electrodes of the semiconductor element by mask exposure, dry film development, etching and dry film peeling steps. A thick conductive sheet having thickness was obtained. The conductor terminals of the conductive sheet in the thickness direction, the electrodes of the semiconductor element, and the corresponding terminals on the substrate are overlapped with each other at the same electrode terminal position, and then heated to 280 degrees by a heat block from the semiconductor element surface. 10kgf / cm ² while
And sunk inside until the conductor terminal reached the opposite surface of the insulating sheet. At this time, generation of decomposition gas or the like was not observed from the insulating sheet. The conductor terminal that reached the opposite surface of the insulating sheet was joined to the electrode of the semiconductor element and the connection terminal of the substrate, and electrical conduction was obtained.
The surface of the semiconductor element and the surface of the substrate were fixed by softening and bonding the insulating sheet. When the shear strength at the connection surface was measured with a push-pull gauge, it was 28 MPa, which was sufficient. In the fracture surface of the test piece, the adhesive resin layer was cohesively fractured, and no foaming was observed.

Example 2 265.8 g of N-methyl-2-pyrrolidone (NMP) was vigorously stirred for 10 minutes while flowing nitrogen gas. Next, 78.9318 g (0.0270 mol) of 1,3-bis (3-aminophenoxy) benzene and 15.9994 g (0.0380 mol) of 2,2-bis (4- (4-aminophenoxy) phenyl) propane And 29.2950 g of α, ω-bis (3-aminopropyl) polydimethylsiloxane (average molecular weight 837,
(0.0350 mol), and heat the system to 60 ° C. and stir until uniform. After homogeneous dissolution, the system was
C., and cooled to 20.5954 g (0.0700 mol) of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 3,3', 4,4'-benzophenonetetracarboxylic dianhydride 9 0.6669 g (0.0300 mol) was added in the form of a powder over 10 minutes, and then stirring was continued for 5 hours. During this time, the flask was kept at 5 ° C. Thereafter, the nitrogen gas inlet tube and the condenser were removed, a Dean-Stark tube filled with xylene was attached to the flask, and 66.4 g of xylene was added to the polyamic acid solution generated in the system.
The system was heated by replacing the ice water bath with an oil bath, and the generated water was removed from the system. After heating for 4 hours, no water was generated from the system. The polyimide resin solution B obtained after cooling was cast on a rolled copper foil having a thickness of 18 μm by a reverse roll coater and then dried to form a 15 μm thick insulating layer sheet, thereby obtaining a polyimide sheet with a copper foil. The drying temperature was a maximum of 200 ° C. and the drying time was 15 minutes. A semiconductor element having electrodes for external connection on the periphery of the circuit surface as an adherend and a substrate having connection terminals at positions corresponding to the electrodes of the semiconductor element were prepared. Laminate a dry film resist on the copper foil surface of the polyimide sheet with copper foil, and form a conductor terminal at a position corresponding to the electrode of the semiconductor element by mask exposure, dry film development, etching and dry film peeling steps. A conductive sheet in the thickness direction was obtained. The conductor terminals of the conductive sheet in the thickness direction, the electrodes of the semiconductor element, and the corresponding terminals on the substrate are overlapped with each other at the same electrode terminal position, and then heated to 280 degrees by a heat block from the semiconductor element surface. While the pressure was applied at a pressure of 10 kgf / cm ² , the conductor terminal was sunk inside until it reached the opposite surface of the insulating sheet. At this time, generation of decomposition gas or the like was not observed from the insulating sheet.
The conductor terminal that reached the opposite surface of the insulating sheet was joined to the electrode of the semiconductor element and the connection terminal of the substrate, and electrical conduction was obtained. The surface of the semiconductor element and the surface of the substrate were fixed by softening and bonding the insulating sheet. When the shear strength at the connection surface was measured with a push-pull gauge, it was 22 MPa, which was sufficient. In the fracture surface of the test piece, the adhesive resin layer was cohesively fractured, and no foaming was observed.

Example 3 The polyimide resin solution I obtained by the method of Example 1 was applied to a polyester film (10
0μm thickness) by casting with a bar coater, maximum 2
After drying at 00 ° C. for 15 minutes, the polyester film was peeled off, whereby a 20 μm-thick flexible self-holding insulating sheet C was obtained. 18 μm is applied to this insulating sheet C.
A rolled copper foil having a thickness of m was passed through two hot rolls at 140 ° C. and a linear pressure of 0.5 kgf / cm to be laminated to obtain a polyimide sheet with a copper foil. As an adherend, a semiconductor element having electrodes for external connection in the periphery and a substrate having connection terminals at positions corresponding to the electrodes of the semiconductor element were prepared. Laminate the dry film resist on the copper foil surface of the polyimide sheet with copper foil, mask exposure, dry film development, etching, dry film peeling and electroless gold plating, the conductor terminal at the position corresponding to the electrode of the semiconductor element Was formed to obtain a conductive sheet in the thickness direction. The conductor terminals of the thickness direction conductive sheet, the electrodes of the semiconductor element, and the corresponding connection terminals on the substrate were overlapped with their electrode terminal positions aligned. Then, the conductor terminals which reached the opposite surface of the insulating sheet by applying a pressure of 10 kgf / cm ² from the semiconductor element surface to the opposite side of the insulating sheet while being heated to 250 ° by a heat block were connected to the electrodes of the semiconductor element and the connection terminals of the substrate. And electrical continuity was obtained. At this time, generation of decomposition gas or the like was not observed from the insulating sheet. Further, the surface of the semiconductor element and the surface of the substrate were firmly fixed by the softening and bonding of the insulating sheet. When the shear strength at the connection surface was measured with a push-pull gauge, the shear strength was 24 MPa, which was sufficient. In the fracture surface of the test piece, the adhesive resin layer was cohesively fractured, and no foaming was observed.

Example 4 A flexible four-layer board was manufactured using a conductive sheet in the thickness direction. First, the first layer and the second layer
The circuit of the layer is formed on a flexible substrate with a double-sided electrolytic copper foil by drilling through holes, through-hole copper plating, dry film lamination, mask exposure, dry film development, etching, and dry film peeling to form a flexible circuit board 1. Obtained. Next, the circuits of the third and fourth layers were formed in the same manner to obtain the flexible circuit board 2. Connection terminals were provided on the second layer and the third layer at opposing positions. The first and fourth layers were coated with thermosetting polyimide as a solder resist and cured. Next, on both sides of the insulating sheet C obtained by the method of Example 3, 12
A polyimide sheet with a double-sided copper foil was obtained by laminating an electrolytic copper foil having a thickness of μm. Laminating a dry film resist on the copper foil surface of the polyimide sheet with copper foil, and performing the steps of mask exposure, dry film development, etching, dry film peeling and electroless solder plating, the second layers of the flexible circuit boards 1 and 2 and A thickness direction conductive sheet was obtained in which conductor terminals were formed so as to face each other at positions corresponding to the connection terminals of the third layer. The conductor terminals of this conductive sheet in the thickness direction and the connection terminal positions of the flexible circuit boards 1 and 2 are aligned and laminated, and the conductor terminals are pressed at a pressure of 10 kgf / cm ² while being heated to 250 degrees by a hot press device. Submerged inside the insulating sheet. The conductor terminals arranged and formed so as to face both surfaces of the insulating sheet sink into the inside of the insulating sheet from the respective surfaces, and are joined to the facing conductor terminals inside the insulating sheet, and the second layer and the second layer. The three-layer connection terminals were also joined to obtain electrical continuity. Further, the second layer surface and the third layer surface of the flexible circuit board were fixed by the softening and bonding of the insulating sheet. 18 at the interface between the insulating sheet and the flexible circuit board using a tensile tester
0 degree peel strength was measured (tensile speed 50 mm / mi)
n) However, 2.1 kgf / cm was sufficient. In the fracture surface of the test piece, the adhesive resin layer was cohesively fractured, and no foaming was observed.

Comparative Example 1 In Example 1, α, ω−
Instead of bis (3-aminopropyl) polydimethylsiloxane having an average molecular weight of 837, an average molecular weight of 16
A polyimide sheet with a copper foil was obtained by the same operation using 58.4500 g (0.0350 mol) of 70.
However, in the thickness direction conductive sheet obtained after forming the conductor terminal, the insulating sheet portion was uneven and brittle, and the subsequent steps could not be performed.

Comparative Example 2 In Example 1, α, ω−
Bis (3-aminopropyl) polydimethylsiloxane having an average molecular weight of 24 instead of 837
8.6982 g (0.0350 mol) of 8.52
It was used and a polyimide sheet with a copper foil was obtained by the same operation. However, even after the conductor terminals are formed, even if the positions of the electrode terminals are adjusted and the connected body is heated and pressed under the same conditions,
The conductor terminal did not sink inside until it reached the opposite surface of the insulating sheet.

Comparative Example 3 In Example 1, 1, 3
-Bis (3-aminophenoxy) benzene was added at 11.69.
36 g (0.0400 mol) and 2,2-bis (4- (4
22.57-aminophenoxy) phenyl) propane
81 g (0.0550 mol) and 8.3500 g of α, ω-bis (3-aminopropyl) polydimethylsiloxane
(Average molecular weight: 837, 0.0050 mol), and a polyimide sheet with a copper foil was obtained by the same operation. However, as in Comparative Example 2, even after the conductor terminals are formed and the electrode terminals are aligned and heated and pressurized with the connected object under the same conditions, the conductor terminals sink inside until they reach the opposite surface of the insulating sheet. Did not.

Comparative Example 4 In Example 1, 1, 3
-Bis (3-aminophenoxy) benzene to 4.385
1 g (0.0150 mol) and 2,2-bis (4- (4-
Aminophenoxy) phenyl) propane is 10.262
8g (0.0150 mol) and 116.9000 of α, ω-bis (3-aminopropyl) polydimethylsiloxane
g (average molecular weight: 837, 0.0700 mol), and a polyimide sheet with a copper foil was obtained in the same manner. But,
In the thickness direction conductive sheet obtained after forming the conductor terminal, the insulating sheet part is brittle, and at the time of heating and pressing with the connected object,
The fluidity of the insulating sheet was large, and the conductor terminals flowed together with the insulating sheet.

(Comparative Example 5) In Example 1, 29.4220 g of pyromellitic dianhydride (0.
1000 mol), and the same reaction procedure was performed. The obtained polyamic acid solution was subjected to a reverse roll coater for 18 hours.
After casting and drying on a rolled copper foil with a thickness of
A thick insulating layer sheet was formed to obtain a polyimide sheet with a copper foil. The drying temperature was a maximum of 250 ° C. with a drying time of 30 minutes. However, even after the conductor terminals were formed and the respective electrode terminals were aligned and heated and pressed under the same conditions as in Example 1, the conductor terminals did not sink inside until they reached the opposite surface of the insulating sheet. . When the obtained polyamic acid solution was heated under the same conditions as in Example 1, the polyimide resin was precipitated in the solution, and a uniform solution was not obtained.

(Comparative Example 6) In Example 1, 1,3-
In place of bis (3-aminophenoxy) benzene and 2,2-bis (4- (4-aminophenoxy) phenyl) propane, 4,4′-diaminodiphenyl ether is replaced with 1
The same reaction procedure was performed using 3.0156 g (0.0650 mol). The obtained polyamic acid solution was cast on a rolled copper foil having a thickness of 18 μm by a reverse roll coater and then dried to form a 15 μm thick insulating layer sheet, thereby obtaining a polyimide sheet with a copper foil. Drying temperature up to 250
Drying time at 30 ° C. was 30 minutes. However, even after the conductor terminals are formed and the positions of the respective electrode terminals are aligned and the object is heated and pressed under the same conditions as in Example 1, the inside of the conductor terminal reaches the opposite surface of the insulating sheet, as in Comparative Example 5. Did not sink. When the obtained polyamic acid solution was heated under the same conditions as in Example 1, the polyimide resin was precipitated in the solution, and a uniform solution was not obtained.

[0037]

According to the thickness direction conductive sheet of the present invention,
Compared to conventional anisotropic conductive sheets, electrical connections and mechanical connections in the thickness direction, such as connections between semiconductor chips and substrates, which are narrower in pitch, and interlayer connections between multilayer boards, are more reliable at lower cost and higher reliability. The electronic device can be downsized.

[Brief description of the drawings]

FIG. 1 is a thickness direction conductive sheet of the present invention in which conductive terminals are arranged on one surface of an insulating sheet.

FIG. 2 is a thickness direction conductive sheet of the present invention in which conductor terminals are arranged so as to face each other on both surfaces of an insulating sheet.

FIG. 3 is a thickness direction conductive sheet of the present invention in which conductor terminals are arranged so as not to face each other on both surfaces of an insulating sheet.

FIG. 4 shows an example of connection between a semiconductor element and a substrate using a sheet for connection in the thickness direction of the present invention.

[Explanation of symbols]

 1: Insulating sheet 2: Conductive terminal 3: Semiconductor element 4: Electrode of semiconductor element 5: Substrate 6: Connection terminal on substrate 7: Heat block

Claims (11)

[Claims] (1) Formula (1) (Wherein R ₁ , R ₂ , R ₃ , and R ₄ are a hydrogen atom or a monovalent aliphatic or aromatic hydrocarbon group having 6 or less carbon atoms, and R ₅ and R ₆ are a divalent group having 1 to 6 carbon atoms. An aliphatic or aromatic hydrocarbon group of k
Amol of silicon diamine represented by an integer of 4 to 10), 2,2-bis {4- (4-aminophenoxy) phenyl} propane, 2,2-bis {4- (4-aminophenoxy) phenyl} Hexafluoropropane, bis {4-
(4-aminophenoxy) phenyl} ether, 1,3
-Bis (3-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 1,4-bis (3
-Aminophenoxy) benzene, 3,4'-diaminodiphenyl ether, 2,5-diamino-p-xylene,
1,3-bis (3-aminopropyl) -1,1,3,3
One or two or more diamines selected from tetramethyldisiloxane and b moles of other diamines as an amine component, and 4,4′-oxydiphthalic dianhydride, 3,3 ′, 4; D mol of one or more tetracarboxylic dianhydrides selected from the group of 4'-biphenyltetracarboxylic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride; E mol of another acid dianhydride is used as an acid component, and 0.1 ≦ a / (a +
b + c) ≦ 0.5, 0.5 ≦ b / (a + b + c) ≦ 0.
9, 0.8 ≦ d / (d + e) ≦ 1,0.9 ≦ (d + e)
Independent terminals made of conductors are arranged on one surface of an insulating sheet substantially made of a polyimide resin reacted at a ratio of /(a+b+c+d+e)≦1.1. When the insulating sheet is softened, the conductor sinks until reaching the opposite surface of the insulating sheet, and conduction between the opposite surface of the insulating sheet and the connected object is obtained through the conductor. A conductive sheet in the thickness direction, wherein the conductive sheet is bonded to a connected object. 2. A mole of silicon diamine represented by the formula (1), 2,2-bis {4- (4-aminophenoxy) phenyl} propane, 2,2-bis {4- (4-aminophenoxy) Phenyl} hexafluoropropane, bis {4-
(4-aminophenoxy) phenyl} ether, 1,3
-Bis (3-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 1,4-bis (3
-Aminophenoxy) benzene, 3,4'-diaminodiphenyl ether, 2,5-diamino-p-xylene,
1,3-bis (3-aminopropyl) -1,1,3,3
One or two or more diamines selected from tetramethyldisiloxane and b moles of other diamines as an amine component, and 4,4′-oxydiphthalic dianhydride, 3,3 ′, 4; D mol of one or more tetracarboxylic dianhydrides selected from the group of 4'-biphenyltetracarboxylic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride; E mol of another acid dianhydride is used as an acid component, and 0.1 ≦ a / (a +
b + c) ≦ 0.5, 0.5 ≦ b / (a + b + c) ≦ 0.
9, 0.8 ≦ d / (d + e) ≦ 1,0.9 ≦ (d + e)
/ (A + b + c + d + e) ≦ Independent terminals made of a conductor are arranged opposite to each other on both surfaces of an insulating sheet substantially made of a polyimide resin reacted at a ratio of 1.1, and At the time of heat compression bonding, the insulating sheet softens, so that the conductor sinks into the insulating sheet until opposing conductors are joined to each other, and is connected to the opposite surface of the insulating sheet through the conductor. A conductive sheet in a thickness direction, wherein conduction with a body is obtained and adhesion with a connected body is performed at the same time. 3. Amol of silicon diamine represented by the formula (1), 2,2-bis {4- (4-aminophenoxy) phenyl} propane, 2,2-bis {4- (4-aminophenoxy) Phenyl} hexafluoropropane, bis {4-
(4-aminophenoxy) phenyl} ether, 1,3
-Bis (3-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 1,4-bis (3
-Aminophenoxy) benzene, 3,4'-diaminodiphenyl ether, 2,5-diamino-p-xylene,
1,3-bis (3-aminopropyl) -1,1,3,3
One or two or more diamines selected from tetramethyldisiloxane and b moles of other diamines as an amine component, and 4,4′-oxydiphthalic dianhydride, 3,3 ′, 4; D mol of one or more tetracarboxylic dianhydrides selected from the group of 4'-biphenyltetracarboxylic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride; E mol of another acid dianhydride is used as an acid component, and 0.1 ≦ a / (a +
b + c) ≦ 0.5, 0.5 ≦ b / (a + b + c) ≦ 0.
9, 0.8 ≦ d / (d + e) ≦ 1,0.9 ≦ (d + e)
Independent terminals made of a conductor are arranged on both surfaces of an insulating sheet substantially made of a polyimide resin reacted at a ratio of /(a+b+c+d+e)≦1.1 so as not to face each other. When the insulating sheet is softened at the time of heat compression, the above-mentioned conductor sinks until it reaches the opposite surface of the insulating sheet, and conduction between the opposite surface of the insulating sheet and the connected object passes through the above-mentioned conductor. A thickness direction conductive sheet characterized in that it is simultaneously obtained and adhered to a connected body. 4. The thickness direction conductive sheet according to claim 1, wherein the thickness of the conductive terminal is in a range of 0.7 to 1.5 times the thickness of the insulating sheet. 5. The thickness direction conductive sheet according to claim 2, wherein the total thickness of the conductor terminals facing each other is in a range of 0.7 to 1.5 times the thickness of the insulating sheet. . 6. Silicon diamine a represented by the formula (1)
Mol, 2,2-bis {4- (4-aminophenoxy) phenyl} propane, 2,2-bis {4- (4-aminophenoxy) phenyl} hexafluoropropane, bis {4
-(4-aminophenoxy) phenyl} ether, 1,
3-bis (3-aminophenoxy) benzene, 1,4-
Bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 1,4-bis (3
-Aminophenoxy) benzene, 3,4'-diaminodiphenyl ether, 2,5-diamino-p-xylene,
1,3-bis (3-aminopropyl) -1,1,3,3
One or two or more diamines selected from tetramethyldisiloxane and b moles of other diamines as an amine component, and 4,4′-oxydiphthalic dianhydride, 3,3 ′, 4; D mol of one or more tetracarboxylic dianhydrides selected from the group of 4'-biphenyltetracarboxylic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride; E mol of another acid dianhydride is used as an acid component, and 0.1 ≦ a / (a +
b + c) ≦ 0.5, 0.5 ≦ b / (a + b + c) ≦ 0.
9, 0.8 ≦ d / (d + e) ≦ 1,0.9 ≦ (d + e)
A step of applying a solution of a polyimide resin reacted in a ratio of /(a+b+c+d+e)≦1.1 as a main solute in an organic solvent onto a conductive foil, and heating to evaporate the solvent in the solution. 5. The method according to claim 1, further comprising the steps of: forming an insulating sheet on the conductive foil, and selectively etching only the conductive foil to form independent conductive terminals in a desired arrangement. Method for producing a conductive sheet in the thickness direction. 7. Silicon diamine a represented by the formula (1)
Mol, 2,2-bis {4- (4-aminophenoxy) phenyl} propane, 2,2-bis {4- (4-aminophenoxy) phenyl} hexafluoropropane, bis {4
-(4-aminophenoxy) phenyl} ether, 1,
3-bis (3-aminophenoxy) benzene, 1,4-
Bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 1,4-bis (3
-Aminophenoxy) benzene, 3,4'-diaminodiphenyl ether, 2,5-diamino-p-xylene,
1,3-bis (3-aminopropyl) -1,1,3,3
One or two or more diamines selected from tetramethyldisiloxane and b moles of other diamines as an amine component, and 4,4′-oxydiphthalic dianhydride, 3,3 ′, 4; D mol of one or more tetracarboxylic dianhydrides selected from the group of 4'-biphenyltetracarboxylic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride; E mol of another acid dianhydride is used as an acid component, and 0.1 ≦ a / (a +
b + c) ≦ 0.5, 0.5 ≦ b / (a + b + c) ≦ 0.
9, 0.8 ≦ d / (d + e) ≦ 1,0.9 ≦ (d + e)
Forming a thin film conductor layer on at least one insulating layer surface of an insulating sheet substantially made of a polyimide resin reacted at a ratio of /(a+b+c+d+e)≦1.1; A step of plating to form conductor terminals in a desired arrangement, and a step of etching and removing a thin-film conductor layer whose surface is not plated to make the conductor terminals electrically independent. 5. The method for producing a conductive sheet in the thickness direction according to any one of 1 to 4. 8. Silicon diamine a represented by the formula (1)
Mol, 2,2-bis {4- (4-aminophenoxy) phenyl} propane, 2,2-bis {4- (4-aminophenoxy) phenyl} hexafluoropropane, bis {4
-(4-aminophenoxy) phenyl} ether, 1,
3-bis (3-aminophenoxy) benzene, 1,4-
Bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 1,4-bis (3
-Aminophenoxy) benzene, 3,4'-diaminodiphenyl ether, 2,5-diamino-p-xylene,
1,3-bis (3-aminopropyl) -1,1,3,3
One or two or more diamines selected from tetramethyldisiloxane and b moles of other diamines as an amine component, and 4,4′-oxydiphthalic dianhydride, 3,3 ′, 4; D mol of one or more tetracarboxylic dianhydrides selected from the group of 4'-biphenyltetracarboxylic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride; E mol of another acid dianhydride is used as an acid component, and 0.1 ≦ a / (a +
b + c) ≦ 0.5, 0.5 ≦ b / (a + b + c) ≦ 0.
9, 0.8 ≦ d / (d + e) ≦ 1,0.9 ≦ (d + e)
A step of forming a conductor layer by thermocompression bonding a conductor foil on at least one insulating layer surface of an insulating sheet substantially made of a polyimide resin reacted at a ratio of /(a+b+c+d+e)≦1.1, only the conductor layer 5. The method of manufacturing a conductive sheet in the thickness direction according to claim 1, further comprising a step of selectively etching the conductive terminals to form independent conductive terminals in a desired arrangement. 9. The method according to claim 6, wherein the sheet-like conductor is a rolled copper foil or an electrolytic copper foil. 10. A method for producing a thickness direction conductive sheet, comprising a step of forming a second conductor layer on a conductor surface of the thickness direction conductive sheet obtained by the production method according to claim 6, 7, or 8. 11. A method of manufacturing a thickness direction conductive sheet, comprising the step of heating and pressing a thickness direction conductive sheet obtained by the manufacturing method according to claim 6, and embedding conductor terminals in an insulating layer. Method.