JP2000119607A - Bonding sheet and method for manufacturing flexible copper-clad laminate using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a bonding sheet excellent in adhesiveness and running property, and to manufacture a flexible copper-clad laminate having excellent characteristics without wrinkles by using such a bonding sheet. Aim. SOLUTION: On one side or both sides of a base film,
An adhesive layer containing an inorganic fine powder is laminated to obtain a bonding sheet. Further, a copper foil is laminated on the surface of the bonding sheet thus obtained, on which the adhesive layer is provided, and continuously heated and pressed to produce a flexible copper-clad laminate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bonding sheet having a two-layer or three-layer structure in which an adhesive layer is provided on one or both sides of a base film, and a method for producing a flexible copper-clad laminate using the same.

[0002]

2. Description of the Related Art In recent years, higher performance and higher functionality of electronic devices have been developed.
The miniaturization is rapidly progressing, and there is an increasing demand for miniaturization and weight reduction of electronic components used in electronic devices. Along with this, the heat resistance, mechanical strength,
Various physical properties such as electrical characteristics are required, and a higher density, higher function, and higher performance are also required for a semiconductor element packaging method and a wiring board for mounting the same.
In particular, semiconductor packages, COL (chip-on-lead)
And LOC (lead on chip) package and MCM
Good bonding sheets that can be suitably used as high-density packaging materials such as (multi-chip modules), printed wiring board materials such as multilayer FPCs (flexible printed circuits), and aerospace materials are required.

[0003] Examples of practical characteristics that a bonding sheet having various uses should have include running properties (slipperiness) and adhesiveness in addition to the above-mentioned various properties. In a bonding sheet having good running properties, the operability and handleability are improved in the winding step of the bonding sheet and the attaching step of the copper foil or the like, and for example, defective parts such as wrinkles on a processed product such as a flexible copper-clad laminate. Can be prevented from occurring. Also, since the adhesiveness of the bonding sheet directly affects the state of lamination with copper foil, etc.,
Of particular importance.

In general, a bonding sheet used for electronic and electric parts has an adhesive layer made of an epoxy resin or an acrylic resin which can be easily processed at a low temperature. However, although these adhesives are easy to process at low temperatures, they are inferior in heat resistance and low in adhesive strength and reliability at high temperatures, so that the properties are reflected in the obtained bonding sheet.

On the other hand, polyimide having high heat resistance and mechanical properties and excellent low dielectric properties is promising as an adhesive for forming an adhesive layer of a bonding sheet. However, polyimide-based adhesives generally have lower adhesiveness than epoxy-based resin and acrylic-based resin adhesives, and are used as insulating materials of organic synthetic polymers such as FPC and TAB (tape).
It has been used as a base film for (bonding), but has hardly been used as an adhesive until now.

There are several examples in which a base film is treated to improve the running property and adhesiveness of a bonding sheet. However, there are many points to be considered, such as that the mechanical properties of the film often change and that sufficient attention is required for processing.

[0007]

SUMMARY OF THE INVENTION Accordingly, the present inventors have solved the above-mentioned problems, and have sufficient mechanical strength.
With the aim of providing a bonding sheet that has excellent properties such as heat resistance, adhesiveness, dimensional stability, low water absorption, and low dielectric properties, and is particularly excellent in workability such as running properties, intensive research has been conducted. As a result, the present invention has been completed.

Further, the present inventors have found that when manufacturing a flexible copper-clad laminate using such a bonding sheet, the conventional thermocompression bonding method uses a small roll to bond in a short period of time. It has been found that the layer has poor bubble removal properties, affects various properties such as heat resistance, solder resistance, moisture absorption, and electrical properties, and leads to deterioration of electronic materials and destruction of materials. Further, the other object of the present invention is to provide a method of manufacturing an excellent flexible copper-clad laminate by making the most of the excellent properties of the novel adhesive layer, and as a result of intensive studies, the present invention is completed. Reached.

[0009]

[Means for Solving the Problems]

The gist of the bonding sheet of the present invention is a bonding sheet comprising an adhesive layer laminated on one or both sides of a base film, wherein the adhesive layer contains an adhesive containing inorganic fine powder or the adhesive. It consists of a reaction cured product of an adhesive.

In such a bonding sheet,
When the inorganic fine powder is SiO_Two, TiO _Two, CaHPO_Four,
And Ca_TwoP_TwoO₇Less selected from the group consisting of
Each having a particle size of 1 μm or more and 100 μm or less
It is to be.

In the bonding sheet, the adhesive layer is formed by adding an inorganic fine powder to a polyamic acid solution having a glass transition temperature of 350 ° C. or less or a polyimide using the same as a precursor.

[0013] In the bonding sheet, the adhesive layer may be represented by the general formula (1):

[0014]

Embedded image

(Wherein m and n are equal to the mole fraction of each repeating unit, m is 0.00 to 0.95, and n is 1.0 to
0.05, the sum of m and n is 1.00, and A and B are tetravalent organic groups, and X and Y are divalent organic groups. Or a polyamic acid solution having the above-mentioned formula (1) or a polyimide using the same as a precursor, to which inorganic fine powder is added.

A and B in the above general formula (1) each represent

[0017]

Embedded image

X and Y are each at least one member selected from the group of tetravalent organic groups shown below.

[0019]

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It may be at least one selected from the group of divalent organic groups shown below.

The gist of the method for producing a flexible copper-clad laminate according to the present invention is as follows. A copper foil is stacked on the surface of any one of the above-mentioned bonding sheets on which the adhesive layer is provided, and is continuously heated and pressed. It is in.

In the method of manufacturing a flexible copper-clad laminate, the continuous heating and press bonding is performed by a double belt press equipped with a preheating furnace and a cooling furnace.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The term "bonding sheet" of the present invention mainly refers to electronic equipment, especially semiconductor packages, C packages.
It refers to a multilayer sheet having a base film and an adhesive layer, which can be suitably used for bonding OL, LOC, MCM, FPC, aerospace equipment parts and the like. The bonding sheet of the present invention is particularly preferably heat-resistant, but is not limited thereto. Here, the “heat-resistant bonding sheet” refers to a bonding sheet in which various properties such as mechanical strength and low dielectric properties hardly decrease under environmental conditions of about 200 ° C. or more and 1000 hours.

The term "heat-fusible" used in the present invention refers to a property of softening the adhesive at a temperature not lower than the glass transition temperature or the melting point of the adhesive and bonding it to a metal such as copper.

The glass transition temperature was measured at a heating rate of 5 ° C./min using a viscoelasticity measuring apparatus DMS2000 manufactured by Seiko Electronic Industry Co., Ltd. The temperature at the intersection of the tangent line around the first inflection point of the storage modulus heating curve is defined as the glass transition temperature.

The bonding sheet of the present invention is obtained by laminating an adhesive layer containing inorganic fine powder on one side or both sides of such a base film.

The base film used in the present invention is F
Any film may be used as long as it can be used as a base film such as a PC. In particular, a polyimide film having excellent heat resistance is preferably used. Specifically, the polyimide film used as the base film may be, for example, a polyimide film such as “Apical (registered trademark; manufactured by Kanegafuchi Chemical Industry Co., Ltd.), but is not limited thereto.
It is obtained by a method of thermally or chemically dehydrating and cyclizing a polyamic acid solution of a precursor. In the present invention, a polymer film having any other structure can be used.

The inorganic fine powder contained in the adhesive layer forms fine projections on the surface of the adhesive layer and contributes to the improvement of the adhesiveness and running property of the bonding sheet. This inorganic fine powder is chemically and physically stable throughout the manufacturing process of the bonding sheet, and is selected with a chemical species, particle size, and addition amount that do not adversely affect various properties required for the manufactured bonding sheet. It should be.

The type of the inorganic fine powder is not particularly limited, but may be any of silica, clay, titania, and orthophosphate compounds of group IIa alkaline earth metals (Be, Mg, Ca, Sr, and Ra). Alternatively, it is preferable to use a combination thereof, especially SiO ₂ , Ti
It is preferable that at least one kind or a combination of two or more kinds selected from the group consisting of O ₂ , CaHPO ₄ , and Ca ₂ P ₂ O ₇ is used.

The particle size of the inorganic fine powder is 1 μm.
It is preferably from m to 100 μm. Particle size is 1
When the thickness is less than μm, it is difficult to form a projection effective for improving the running property and adhesiveness of the bonding sheet.
If m or more, the base film or the copper foil is physically damaged. Any commercially available product can be used as long as it is an inorganic fine powder having a particle size in this range. Alternatively, an inorganic fine powder pulverized to an appropriate particle size can be used.

The proportion of the inorganic fine powder to be added varies depending on the kind.
It is preferable to add it in the range of 0.5% by weight. When the addition ratio is less than 0.1% by weight, the number of protrusions formed on the surface of the adhesive layer is small, and the effect of improving running properties and adhesiveness is reduced. If it exceeds 0.5% by weight, it is difficult to uniformly disperse the inorganic fine powder in the adhesive, and the uniformity of the adhesive layer may be impaired.

The addition of the inorganic fine powder can be performed by a method for ensuring uniformity of dispersion in the production process of the adhesive. That is, the inorganic fine powder may be added at any stage of the initial stage of polymerization of the adhesive, at the end of the polymerization, or at an intermediate stage of the polymerization. When adding an inorganic fine powder, the powder can be added directly to the adhesive as it is, but it can also be dispersed in an organic solvent or the like in advance, or dispersed in a dilute adhesive solution, and then added. it can.

The adhesive to which the inorganic fine powder is added is not particularly limited, and any known adhesive such as an epoxy resin or an acrylic resin can be used. In order to obtain a bonding sheet having particularly high heat resistance, a polyimide-based adhesive can be preferably used. Polyimide is obtained by heating polycondensation of a polyamic acid in a solid or solution state. However, in general, polyimide is almost insoluble in the closed state,
It is necessary to select a type of polyimide adhesive having sufficient fluidity because it does not melt and does not show fluidity.

A preferred adhesive is a polyamic acid solution having a glass transition temperature of 350 ° C. or lower, or a polyimide using the same as a precursor.

An example of producing an adhesive obtained by adding an inorganic fine powder to a polyimide-based adhesive will be described below.

General formula (1)

[0037]

Embedded image

(Wherein m and n are equal to each repeating unit mole fraction, m is 0.00 to 0.95, and n is 1.0 to
0.05, the sum of m and n is 1.00, and A and B are tetravalent organic groups, and X and Y are divalent organic groups. Or a polyimide having the same as a precursor can be used as an adhesive.

A and B in the general formula (1) are

[0040]

Embedded image

X and Y are each at least one selected from the group of tetravalent organic groups shown below.

[0042]

Embedded image

It may be at least one selected from the group of divalent organic groups shown below.

A specific example of a copolymer based on a preferable combination of a diamine and an acid anhydride is 2,2-bis (4-hydroxyphenyl) propanebenzodiate-3,
3 ', 4,4'-tetracarboxylic dianhydride (hereinafter referred to as E
A copolymer obtained from SDA) and bis (2- (4-aminophenoxy) ethoxy) ethane (hereinafter referred to as DA3EG), and 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride A copolymer obtained from (BTDA), 3,3 ′, 4,4′-ethylene glycol benzoate tetracarboxylic dianhydride (hereinafter referred to as TMEG), DA3EG and BAPP,
And copolymers obtained from ESDA, BTDA and DA3EG, but are not limited thereto.

The polyamic acid copolymer is obtained by reacting an acid dianhydride with a diamine in an organic solvent. At this time, first, an acid dianhydride is dissolved or diffused in an organic solvent in an atmosphere of an inert gas such as argon or nitrogen, and one or more diamines are added to the solution in a solid state or It may be added in a state of being dissolved in an organic solvent solution. Further, a mixture of one kind of acid dianhydride of the same or another kind with the acid dianhydride added first is added in a solid state or in a state of an organic solvent solution to obtain a polyamic acid solution which is a precursor of polyimide. be able to.

Various other methods for preparing a polyamic acid copolymer solution are known to those skilled in the art. Contrary to the above addition procedure, a diamine organic solvent solution may be prepared first, and a solid acid dianhydride or acid dianhydride organic solvent solution may be added to this solution. The reaction temperature at this time is -1
0 ° C to 0 ° C is preferred. The reaction time is 30 minutes to 3 hours. By this reaction, an adhesive of a polyamic acid solution which is a precursor of the thermoplastic polyimide is prepared.

Examples of the organic solvent used in the synthesis reaction of the polyamic acid include sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, formamide solvents such as N, N dimethylformamide and N, N diethylformamide, and N, N dimethyl solvent. Acetamide solvents such as acetamide and N, N diethylacetamide can be mentioned. These can be used alone or as a mixture of two or more solvents. Further, a mixed solvent composed of these polar solvents and a non-solvent of polyamic acid can also be used. Examples of the non-solvent for the polyamic acid include acetone, methanol, ethanol, isopropanol, benzene, and methyl cellosolve.

The adhesive for a bonding sheet according to the present invention can be prepared by adding an inorganic fine powder to the obtained polyamic acid solution or by adding an inorganic fine powder before or during the above polymerization.

After the adhesive thus obtained is cast or applied on one or both sides of the base film,
After heating and drying, the heat-resistant bonding sheet of the present invention is obtained. Epoxy-based, acrylic-based, and polyimide-based adhesives, regardless of the type of adhesive used, can be used by laminating a film-like adhesive layer obtained from an adhesive solution on a base film for a bonding sheet. is there.

The method for applying the adhesive containing the inorganic fine powder to the base film is not particularly limited, and any known method can be used. For example, the polyamic acid solution can be cast or applied onto the base film using a rotary coater, knife coater, doctor blade, flow coater. Alternatively, an adhesive film already formed into a film is overlaid on the base film and thermocompression-bonded.

A bonding sheet 10 having a two-layer structure by applying an adhesive 14 to one surface of a base film 12 is shown in FIG.
As shown in FIG.
FIG. 1 (b) shows a bonding sheet 20 having a three-layer structure formed by applying an adhesive.

The bonding sheet thus obtained can be used for various applications. The bonding sheet can be made into a laminate, for example, by laminating a metal foil on one or both sides thereof. The type of metal is not particularly limited, and any metal foil may be laminated. Particularly widely used is to form a flexible copper-clad laminate by laminating copper foils. The method for producing the flexible copper-clad laminate is not particularly limited.
That is, a method of laminating a copper foil on an adhesive layer on one or both sides of a bonding sheet and sandwiching it between two small-diameter cylinders and pressing in a short time; bonding the bonding sheet and the copper foil using a vacuum forming press machine Any method such as a method of thermocompression bonding in a vacuum state, a method of continuous thermocompression bonding, and other methods can be used.

Particularly preferred is a continuous thermocompression bonding method. Here, the continuous thermocompression bonding method refers to any of a method of continuously heating and pressing at a specific point, and a method of continuously heating and pressing. According to the continuous thermocompression bonding method, regardless of the type of the adhesive, the bonding sheet provided with the adhesive layer containing the inorganic fine powder and the copper foil are bonded together without air or wrinkles. This method is also used when stacking metal foils other than copper foil.

Although not limited, specifically, for example, a thermocompression bonding apparatus 30 as shown in FIG. 2 can be used.
In the thermocompression bonding device 30, the bonding sheet 36 and the copper foil 34 are fed out onto an endless belt 38 and overlapped. First, the multilayer body of the bonding sheet 36 and the copper foil 34 is heated by the preheating unit 44. The temperature of the preheating section differs depending on the constituent material of the bonding sheet. Usually, the temperature of the preheating section is set so that the multilayer body has a temperature slightly higher than the glass transition temperature of the adhesive layer. The laminated body to which heat is applied is thermocompression-bonded by a pair of pressure rolls 32, and the obtained flexible copper-clad laminate 4 is obtained.
0 is wound into a product 42. At this time, a plurality of pressure rolls may be provided to perform thermocompression bonding continuously. Furthermore, a pair or a plurality of pressure rolls can be put in a chamber set to a specific temperature, and the temperature of the multilayer body can be efficiently maintained.

Further, a thermocompression bonding apparatus 50 of a double belt press (hereinafter referred to as "DBP") type as shown in FIG.
(Double belt press device) can also be used. In the thermocompression bonding apparatus 50, the bonding sheet 56 and the copper foil 54 are fed out, and are stacked and carried between the two endless belts 58 and 58 '. The multilayer body of the bonding sheet 56 and the copper foil 54 is
Heat is applied in the preheating section 64 while being sandwiched between the endless belts 58 and 58 '. The temperature of the preheating section differs depending on the constituent material of the bonding sheet. Usually, the temperature of the preheating section is set so that the multilayer body has a temperature slightly higher than the glass transition temperature of the adhesive layer. The heated multilayer body is thermocompression-bonded by a pair of pressure rolls 52 while being efficiently kept warm by the two endless belts 58 and 58 '. The obtained laminate is forcibly cooled by the cooling unit 66 and the flexible copper-clad laminate 60
Is obtained. At this time, a plurality of pressure rolls may be provided to perform thermocompression bonding continuously. Further, a pair of or a plurality of pressure rolls may be placed in a chamber set at a specific temperature to efficiently maintain the temperature of the multilayer body. The cooling section can be omitted.

By processing the bonding sheet and the copper foil of the present invention, a flexible copper-clad laminate can be manufactured in this way. Furthermore, in order to maintain the appearance of the copper foil, a flexible copper-clad laminate can be produced by using a material known to those skilled in the art such as a release film, an aluminum foil for release, and release paper. The specific mode is almost the same as when no release film is used. Copper foil 54 of FIG.
Is further laminated on the outside of the sheet, respectively, and the bonding sheet 56, the copper foil 54, and the multilayer body of the release film 55 are sandwiched between the two endless belts 58 and 58 'of the thermocompression bonding apparatus 50, Preheating section 64,
The flexible copper-clad laminate 60 is obtained by passing through a pair or a plurality of pressure rolls 52 and a cooling unit 66. At this time, the release film 55 is attached to the flexible copper-clad laminate 6.
It is wound separately from 0.

By processing with a DBP device, a sufficient residence time for heat fusion can be passed. Also,
The effect of the moisture contained in the bonding sheet can be eliminated by the preheating section, and foaming and the like can be suppressed. In addition, it is possible to eliminate the possibility of appearance defects such as wrinkles caused by differences in the coefficient of linear expansion of each material after thermal lamination.

Hereinafter, the adhesive for a heat-resistant bonding sheet and the heat-resistant bonding sheet according to the present invention will be described in more detail with reference to Examples. However, the present invention is not limited to the knowledge of a person skilled in the art without departing from the spirit thereof. Based on the above, various modifications, changes and modifications can be made. Therefore, the present invention is not limited by these examples.

[0059]

(Example 1) An adhesive for a heat-resistant bonding sheet of the present invention was obtained. First, the whole system was cooled with ice water, and 33.2 g of 3,3 ′, 4,4 ′ benzophenonetetracarboxylic dianhydride (hereinafter referred to as BTDA) was placed in a 2000 ml three-neck separable flask purged with nitrogen.
87 g of dimethylformamide (hereinafter, referred to as DMF) was taken and sufficiently dissolved by stirring with a stirrer. Subsequently, 43.1 g of 2,2'bis [4- (4-aminophenoxy) phenyl] propane (hereinafter referred to as "BAPP") was charged with 20 g of DMF and reacted. After stirring for 15 minutes, 76.0 g of 3,3 ', 4,4'-ethylene glycol dibenzoate tetracarboxylic dianhydride (hereinafter, TMEG) was added to 1
Charged with 50 g of DMF. After stirring for 15 minutes, 80.0 g of BAPP was charged using 150 g of DMF and reacted. After stirring for 30 minutes, an additional 3.1
g of TMEG in 44.5 g of DMF was gradually added while paying attention to the viscosity of the solution in the flask, and then left for 1 hour with stirring. Thereafter, 106 g of DMF was charged and stirred to obtain a polyamic acid solution. To this solution, 0.3 g of CaHPO ₄ , which corresponds to about 0.13% by weight of the total solid content, was added, and the mixture was stirred well until it became uniform to obtain an adhesive to which inorganic fine powder was added.

Next, the polyamic acid solution was applied to a base film (Apical (registered trademark; manufactured by Kaneka Chemical Industry Co., Ltd.)
Product name: applied on both sides of Apical 12.5 using a bar coater, heated in a drying furnace at 100 ° C. for 6 minutes, and then fixed to the metal support together with the base film at 150 ° C. , 200 ° C, 300 ° C for 6 minutes each,
A bonding sheet was obtained.

A copper foil is placed on the adhesive layer surface of the obtained bonding sheet, and a release film (heat-resistant film) is placed thereon.
And a double-sided copper-clad laminate was obtained using the DBP-type apparatus 50 shown in FIG. At this time, the preheating unit 64
° C, the cooling unit 66 was set at 50 ° C, and the pressure roll was set at 260 ° C, 10 kg / cm ² . The feed speed was 1 m / min.

The obtained copper-clad laminate was subjected to JIS C
The peel strength (kg / cm) was measured according to -6481. As a result, the value was 1.5 kg / cm. Further, the dynamic friction coefficient of the bonding sheet was determined according to ASTM D-1894.
Measured in the machine direction of the film according to -63. As a result, the dynamic friction coefficient was 0.55. Wrinkles and the like were not actually generated when the bonding sheet traveled, and it was confirmed that the slipperiness was good.

Comparative Example 1 For comparison, an adhesive different from that of the example was obtained. First, the entire system was cooled with ice water and placed in a 2000 ml three-neck separable flask purged with nitrogen.
3.2 g of 3,3 ', 4,4'benzophenonetetracarboxylic dianhydride (hereinafter referred to as BTDA), 287
g of dimethylformamide (hereinafter, referred to as DMF) was taken and sufficiently dissolved by stirring with a stirrer. Subsequently, 43.1 g of 2,2'bis [4-
(4-aminophenoxy) phenyl] propane (hereinafter, referred to as “
It is called BAPP. ) Was added and reacted using 20 g of DMF. After 15 minutes of stirring, 76.0 g of 3,3 '
Of 4,4,4'-ethylene glycol dibenzoate tetracarboxylic dianhydride (hereinafter referred to as TMEG)
Of DMF. After stirring for 15 minutes, 8
0.0 g of BAPP was charged using 150 g of DMF and reacted. After stirring for 30 minutes, 2.0 g of TMEG
Was dissolved in 41.3 g of DMF and gradually added while paying attention to the viscosity of the solution in the flask, and then left for 1 hour with stirring. Thereafter, 106 g of DMF was charged and stirred to obtain a polyamic acid solution. The inorganic fine powder used in Example 1 was not added.

Next, this polyamic acid solution was used in Example 1
In the same manner as in the above, it was applied on both sides of a base film (Apical 12.5) and dried by heating in a drying furnace to obtain a bonding sheet.

Further, in the same manner as in Example 1, a copper foil was laminated on the adhesive layer surface of the obtained bonding sheet, and a release film (heat-resistant film) was provided thereon.
Using a BP apparatus, heating and pressing were performed under the same conditions as in Example 1 to obtain a double-sided copper-clad laminate.

The dynamic friction coefficient of the bonding sheet measured by ASTM D-1894-63 was greater than 0.90, the slipperiness of the actual bonding sheet was poor, and a wrinkle-free flexible copper-clad laminate could not be obtained. . Peel strength of flexible copper-clad laminate (kg
/ Cm) was 1.0 kg / cm.

Comparative Example 2 An adhesive was obtained in the same manner as in Comparative Example 1, and the same inorganic fine powder as in Example 1 was added. This adhesive was applied to a base film to obtain a bonding sheet.

A flexible copper-clad laminate was prepared from the obtained bonding sheet using an apparatus in which the preheating section was omitted from the DBP apparatus shown in FIG. Wrinkling and bubble-like defects could not be eliminated. The peel strength (kg / cm) of the obtained double-sided copper-clad laminate was 1.1 kg / cm on both sides.

From the above Examples and Comparative Examples, the slipperiness of a bonding sheet in which a specific inorganic fine powder is added and dispersed is remarkably improved as compared with the non-added bonding sheet, and it is possible to reduce troubles generated during processing. I knew I could do it. In addition, by using a DBP device having a preheating furnace and a cooling furnace to heat and pressurize, there is no void in the adhesive layer,
A heat-resistant flexible copper-clad laminate having high peel strength has been obtained continuously.

[0070]

The bonding sheet of the present invention is excellent in heat resistance, adhesiveness and running properties, and is suitable for multilayer FPC, rigid-flex board material, COL and LOC packages,
It is suitable for use in new high-density packaging materials such as MCM, and can be used for a wide variety of other uses.

Further, the flexible copper-clad laminate obtained according to the present invention is excellent in the bubble removal property of the adhesive layer during processing,
Excellent in various properties such as heat resistance, solder resistance, moisture absorption, electrical properties, adhesiveness, etc.It is suitable for new high-density mounting materials such as multilayer FPC, rigid-flex board material, COL and LOC package, MCM, etc. Other uses are not particularly limited.

[0072]

[Brief description of the drawings]

FIG. 1 is an enlarged schematic sectional view showing a heat-resistant bonding sheet having a two-layer structure (a) and a three-layer structure (b) according to the present invention.

FIG. 2 is a schematic view showing an example of a thermocompression bonding apparatus used for manufacturing a flexible copper-clad laminate of the present invention.

FIG. 3 is a schematic view showing an example of a DBP device used for manufacturing a flexible copper-clad laminate of the present invention.

[Explanation of symbols]

 10, 20; heat-resistant bonding sheets 12, 22; base films 14, 24; adhesive layers 30, 50; thermocompression bonding devices 32, 52; pressure rolls 34, 54; copper foil 55; release films 36, 56; Bonding sheets 38, 58, 58 '; Endless belts 40, 60; Flexible copper-clad laminates 42, 62; Winding products 44, 64; Preheating unit 66; Cooling unit

Continued on the front page (72) Inventor Naoki Hase 1-25-1 Hietsuji, Otsu City F-term (reference) 4F100 AA00B AA00C AA04B AA04C AA17B AA17C AA20B AA20C AA21B AA21C AB17D AB33D AK01A AK49 AK49B AK49BA03 BA00 BA10B BA10C BA10D CA23B CA23C DE01B DE01C EJ172 EJ182 EJ422 GB41 JA05B JA05C JB12B JB12C JJ03 JK06 JK14 JL11 JL11B JL11C YY00B YY00C 4J004 AA11 AB05 CA06 CB03 FA05 GA03 GA03 GA03 GA03 GA03 GA03 GA03 GA03 GA03 GA03 MB05 NA19 NA20 PA30 PA33 PB05 PB08

Claims (7)

[Claims] 1. A bonding sheet comprising an adhesive layer laminated on one or both sides of a base film, wherein the adhesive layer is made of an adhesive containing inorganic fine powder or a cured product of the adhesive. Characteristic bonding sheet. 2. The method according to claim 1, wherein the inorganic fine powder is made of SiO ₂ , TiO _2
2 , at least one selected from the group consisting of CaHPO ₄ and Ca ₂ P ₂ O ₇ , having a particle size of 1 μm
The bonding sheet according to claim 1, wherein the thickness is at least 100 μm. 3. The adhesive layer according to claim 1, wherein an inorganic fine powder is added to a polyamic acid solution having a glass transition temperature of 350 ° C. or lower or a polyimide having the glass transition temperature as a precursor. 4. The bonding sheet according to 1. 4. The adhesive layer according to claim 1, wherein the adhesive layer has a general formula (1). Wherein m and n are equal to each repeating unit mole fraction;
m is 0.00 to 0.95, n is 1.0 to 0.05, the sum of m and n is 1.00, A and B are tetravalent organic groups, and X and Y are 2 And an inorganic fine powder is added to a heat-fusable polyamic acid solution represented by the following formula (1) or a polyimide obtained by using the solution as a precursor. The bonding sheet according to any one of the above. 5. A and B in the general formula (1) each represent And at least one selected from the group of tetravalent organic groups shown below, wherein X and Y are each 5. The bonding sheet according to claim 4, wherein the bonding sheet is at least one selected from the group of divalent organic groups: 6. A flexible copper-clad laminate characterized in that a copper foil is laminated on the surface of the bonding sheet according to any one of claims 1 to 5 on which the adhesive layer is provided, and is continuously heated and pressed. Manufacturing method. 7. The method for producing a flexible copper-clad laminate according to claim 6, wherein the continuous thermal compression bonding is performed by a double belt press equipped with a preheating furnace and a cooling furnace. [0000]