KR20070120555A - Method for producing flexible copper-clad laminated substrate and multi-layer laminate - Google Patents

Abstract

The purpose is to reduce the curling of a flexible cupper-clad laminated substrate which occurs when a resin solution is applied directly on an ultrathin copper foil with a heat-resistant carrier to form a resin layer on the substrate and then the carrier is peeled off. A method for producing a flexible copper-clad laminated substrate (6) having a resin layer (1) and an ultrathin copper foil (2), the method comprising, in an ultrathin copper foil with a heat-resistant carrier in which the ultrathin copper foil (2) is provided on the carrier (4) thorough a releasable layer (3), applying a resin solution onto the ultrathin copper foil, drying and thermally treating the resin solution to form the resin layer (1) which is composed of one or more layers on the ultrathin copper foil with the heat-resistant carrier, thereby producing a multi-layer laminate, and removing the carrier from the laminate. In the multi-layer laminate provided before the removal of the carrier, a force for causing the laminate to curl inwardly on the carrier-side is applied to the laminate and then the carrier is peeled off from the substrate. Thus, a flexible cupper-clad laminated substrate (6) can be produced which is reduced in the degree of curling.

Description

TECHNICAL FOR PRODUCING FLEXIBLE COPPER-CLAD LAMINATED SUBSTRATE AND MULTI-LAYER LAMINATE}

The present invention relates to a method for producing a flexible copper clad laminate and a multilayer laminate, and more particularly, to a method for producing a flexible copper clad laminate using an ultrathin copper foil with a heat resistant carrier, and an ultrathin copper foil with a heat resistant carrier. The present invention relates to a multilayer laminate obtained by coating a resin solution.

Background Art In recent years, as the electronic information devices have become more functional and lighter and thinner, higher density of substrate wiring is required, and flexible copper-clad laminates capable of coping with narrower wiring patterns have been required. As the circuit formation method of image development, the subtractive method of etching copper foil and forming wiring is mainstream. However, for further fine wiring processing of 30 탆 pitch or less, in the subtractive method, since the wiring shape becomes trapezoidal, the area of the mounting portion is reduced during mounting of the IC chip, resulting in poor mounting. In addition, since a sufficient cross-sectional area of the wiring cannot be obtained, there is a high possibility that problems such as a decrease in electrical conductivity also occur. Therefore, when the pinning proceeds, a semiadditive process is used. In the semiadditive process, the material which formed the ultra-thin copper foil layer which plays the role of the conductive layer at the time of electroplating on insulating films, such as a polyimide film, is needed. As this material, the material which formed the ultra-thin copper layer on the insulating films, such as polyimide, by the sputtering method and the electrolytic plating method under vacuum is proposed.

On the other hand, in recent years, the material using the copper foil with a carrier which consists of a peeling layer and an ultra-thin copper foil layer on the foil- or film-shaped carrier is proposed (refer patent document 3). This copper foil with a carrier is applicable to the casting method which apply | coats and imidates a polyimide varnish, or the lamination method which thermo-compresses the polyimide film with an adhesive layer by high temperature pressurization, and after manufacture of a multilayer laminated body, By peeling off, it can be set as the flexible copper clad laminated substrate which consists of copper foil and polyimide resin of thickness of 10 micrometers or less. However, the flexible copper clad laminate produced by this method has a drawback that curls are generated due to the stress applied at the time of peeling the carrier because the copper foil thickness is 10 µm or less and the rigidity is low. The technique which flattens the board | substrate after carrier foil peeling is calculated | required.

When curl exists in a flexible printed circuit board, there exists a possibility that a problem may arise at the time of a microwiring process or a mounting, The following proposal is made. For example, in following patent document 1 and following patent document 2, the range of the thermal expansion coefficient which can suppress the curl of a flexible printed circuit board, and the range of the thickness of the resin layer from which a thermal expansion coefficient differs are specified. However, these are related to a material formed by laminating or directly coating a resin layer on a copper foil of 18 µm or more, which is also widely used commercially, and the effect of curl suppression was not sufficiently satisfactory for ultra-thin copper foil having a thickness of less than 10 µm. That is, the flexible copper clad laminated substrate manufactured by the ultra-thin copper foil with carrier foil is a material in which the ultra-thin copper foil of less than 10 micrometers, advantageously 1-3 micrometers is formed, and a resin layer is formed on the ultra-thin copper foil in the manufacturing process. When the carrier was removed afterwards, a stress was generated on the ultrathin copper foil side, and curling occurred, and it was difficult to suppress the curl at the thickness of the ultrathin copper foil. In other words, even if the copper expansion plate without a curl is manufactured by controlling the coefficient of thermal expansion or the like before peeling the carrier, curling occurs due to the stress at the time of peeling the carrier.

Moreover, in the flexible copper clad laminated board which can respond to the thin wire pattern etching using an ultra-thin copper foil, there exists a problem in the adhesive strength of an ultra-thin copper foil and a resin layer generally, For example, although patent document 4 proposes more than 0.7 kN / m. Indeed, in applications where fine wiring such as COF applications and high temperature mounting are required, further improvement in adhesive strength is required.

Patent Document 1: Japanese Patent Application Laid-open No. Hei 8-250860

Patent Document 2: Japanese Patent Application Laid-Open No. 2000-188445

Patent Document 3: JP 2003-340963 A

Patent Document 4: Japanese Patent Application Laid-Open No. 2004-42579

The present invention uses ultra-thin copper foil with a heat-resistant carrier, directly coats a resin solution such as polyimide resin on the ultra-thin copper foil to form a resin layer, and then curls the flexible copper-clad laminate generated when the carrier is peeled off. It is an object of the present invention to provide a flexible copper clad laminated substrate which suppresses the occurrence and has a high adhesive strength between the ultrathin copper foil and the resin layer, and also has excellent workability in a fine circuit forming step.

MEANS TO SOLVE THE PROBLEM As a result of earnest research in view of the said subject, in the manufacturing method of the flexible copper clad laminated board using the ultra-thin copper foil with a heat resistant carrier, the carrier is controlled by controlling the curl of a laminated body before peeling a support body (carrier). It was found that a material was obtained in which the curl of the flexible copper clad laminated substrate after foil peeling was suppressed, thereby completing the present invention.

That is, this invention coats a resin solution on the ultra-thin copper foil of the ultra-thin copper foil with a heat resistant carrier in which the ultra-thin copper foil with the ultra-thin copper foil is formed on a carrier, and dried and heat-processed to the ultra-thin copper foil with a heat resistant carrier. In the method of manufacturing a flexible copper clad laminated substrate comprising a resin layer and an ultrathin copper foil, after which the carrier is peeled off to form a multilayer laminate having at least one resin layer formed thereon, the carrier side of the multilayer laminate before peeling. A method of manufacturing a flexible copper clad laminate, characterized in that a flexible copper clad laminated substrate is produced, which generates a force to curl and suppresses the amount of curl measured by a 50 × 50 mm sample within ± 3 mm by peeling the carrier.

Moreover, this invention coats a resin solution on the ultra-thin copper foil of the ultra-thin copper foil with a heat resistant carrier in which the ultra-thin copper foil with the ultra-thin copper foil is formed on a carrier, and dried and heat-processed to the ultra-thin copper foil with a heat resistant carrier. be a multi-layer laminate to form a resin layer, the resin layer, in order from the near ultra-thin copper foil with a thermal expansion coefficient ^{20 × 10 -6 (l / K} ) or more high heat-expandable resin, the thermal expansion coefficient ^{20 × 10 -6 (l / K} ) A low-expansion resin layer of less than 20 and a high thermal expansion resin layer having a thermal expansion coefficient of 20 × 10 ⁻⁶ (l / K) or more are laminated sequentially, and the thermal expansion coefficient of the entire resin layer is 15 × 10 ^{−6 to} 25 × 10 ^−6. (l / K), and the ratio (t _a / t _c ) of the thickness t _a of the high thermal expansion resin layer on the ultrathin copper foil side to the thickness t _c of the high thermal expansion resin layer of the outermost layer is 0.25-0.95, and the resin layer The total thickness of is 10-50 micrometers, It is a multilayer laminated body characterized by the above-mentioned.

The ultra-thin copper foil with a heat resistant carrier used by the manufacturing method of this invention uses what the ultra-thin copper foil is formed through the peeling layer on the film-form or thin carrier (support). If a preferable carrier is illustrated, copper, stainless steel, aluminum, alloy foil or heat-resistant resin film which has them as a main component etc. are mentioned. Among these, copper foil or the alloy foil mainly containing copper is preferable because it is excellent in handling property and inexpensive.

Since ultra-thin copper foil with a heat resistant carrier is directly coated with a resin solution on the ultra-thin copper foil, it is necessary to be difficult to deform to some extent, and for that purpose, it is necessary to have a constant thickness. The thickness range of a carrier becomes like this. Preferably it is the range of 5-100 micrometers, More preferably, it is the range of 12-50 micrometers. If the thickness of the carrier is too thin, the carrier property in the manufacture of the flexible copper clad laminated substrate is not stable, and even if too thick, the applicability of the reuse of the carrier is difficult, resulting in waste.

Since the peeling layer in the ultra-thin copper foil with a heat resistant carrier is formed for the purpose of easy peeling (or the purpose of providing weak adhesiveness) of an ultra-thin copper foil and a carrier, it is preferable that the thickness is thin, 0.5 It is preferable that it is micrometer or less, and it is more preferable to exist in the range of 50-100 nm. The release layer is not particularly limited as long as it can stably facilitate the peeling of the heat-resistant carrier foil and the ultra-thin copper foil of the support, but includes at least one selected from a compound containing copper, chromium, nickel, cobalt or elements thereof. It is preferable. Moreover, the organic compound type material as described in patent document 3 can also be used, and a weak adhesive agent can also be used as needed.

The peeling layer may remain on the support side after the carrier peeling or may be transferred to the ultrathin copper foil side of the flexible copper clad laminate. However, when it is a case where a peeling layer is transcribe | transferred to ultra-thin copper foil and it inhibits the property of a conductor, it is preferable to remove by a well-known method.

The ultra-thin copper foil in the ultra-thin copper foil with a heat resistant carrier is formed from copper or the alloy mainly having copper. In order to form a fine pattern at the time of circuit formation after manufacture of a flexible copper clad laminated board, the thickness of an ultra-thin copper foil has the preferable range of 0.1-10 micrometers, The range of 0.1-6 micrometers is more preferable, The range is most preferred. The preferable range of surface roughness (Rz) in an ultra-thin copper foil is 1.0 micrometer or less from a viewpoint of etching property, More preferably, it is the range of 0.01-0.1 micrometer. Regarding the surface roughness, it is preferable that the surface on the side on which the resin solution is coated is in the above range, but since both surfaces are in the above range, a flexible copper clad laminate having excellent pattern shape and linearity after circuit formation can be obtained. Can be. In addition, said Rz represents the ten-point average roughness (JIS B0601-1994) in surface roughness.

In the present invention, a resin solution is directly coated on the ultrathin copper foil of the ultrathin copper foil with the heat resistant carrier, whereby a flexible copper clad laminate having excellent adhesion between the ultrathin copper foil and the resin layer can be obtained. Here, it is preferable that the resin solution melt | dissolved the polyimide resin or the polyimide precursor resin in the solvent from a viewpoint of ensuring the heat resistance of an insulating layer. The polyimide resin used in the present invention refers to one having an imide bond in the resin skeleton, and refers to polyimide, polyamideimide, polyimide ester, polybenzimidazole and the like.

In this invention, it is preferable that the resin layer directly coated on the ultra-thin copper foil is a layer of the said polyimide resin or polyimide precursor resin, and even if it is a single layer structure by single resin, it is good also as a multilayer structure by 2 or more types of resin. In the case where a plurality of resin layers formed on the ultrathin copper foil are used, at least one layer of high thermal expansion resin layer having a thermal expansion coefficient (linear expansion coefficient) of 20 × 10 ⁻⁶ (l / K) or more and a thermal expansion coefficient of 20 × 10 ⁻⁶ It is preferable to set it as the multilayer structure of two or more layers with the at least 1 layer of low-expansion resin layer less than (l / K). In this case, the coefficient of thermal expansion of the entire resin layer is in the range of 15 × 10 ^{-6 to} 25 × 10 ^-6 (l / K), preferably in the range of 15 × 10 ^-6 to 23 × 10 ^-6 (l / K). More preferably, it is preferable to set it as the multilayer polyimide resin layer in the range of 15x10 <^-6> -20x10 <^-6> (l / K).

In the present invention, the high thermal expansion resin layer and the low thermal expansion resin layer have a resin layer having a coefficient of linear expansion higher than that on the basis of a simple average value of the coefficient of thermal expansion of each component resin layer of the insulator forming the multilayer structure. Is referred to as a high thermal expansion resin layer, and a resin layer having a lower coefficient of linear expansion is called a low thermal expansion resin layer. Here, the coefficient of linear expansion of the high thermal expansion resin layer is 20 × 10 ⁻⁶ (l / K) or more, preferably 30 × 10 ^{−6 to} 100 × 10 ⁻⁶ (l / K). The coefficient of linear expansion of the low thermal expansion resin layer is preferably less than 20 × 10 ⁻⁶ (l / K), preferably 0 × 10 ⁻⁶ to ¹⁹ × 10 ⁻⁶ (l / K). In addition, it is preferable that there is a difference between the high thermal expansion resin layer and the low thermal expansion resin layer in the thermal expansion coefficient of 5 × 10 ⁻⁶ (l / K) or more, preferably 10 × 10 ⁻⁶ (l / K) or more. .

The polyimide resin can be produced by selecting a diamine and an acid dianhydride which are known raw materials and reacting in a solvent. 4,4'-diaminodiphenyl ether (DAPE), 1,3-bis (4-aminophenoxy) benzene (1,3-BAB), 2,2'-bis [4- ( At least one diamine component selected from 4-aminophenoxy) phenyl] propane (BAPP), 4,4'-diamino-2,2'-dimethylbiphenyl (DADMB), and pyromellitic anhydride (PMDA) , 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3', 4,4'-benzophenonetetracarboxylic dianhydride (BTDA), 3,3 ', It is preferable to use the polyimide precursor resin solution obtained by making at least 1 type of acid anhydride component chosen from 4,4'- diphenyl sulfone tetracarboxylic dianhydride (DSDA) into each main component, and reacting these. About the layer which contact | connects an ultra-thin copper foil, it is preferable that it is a high thermally expansible resin layer from a viewpoint of making the adhesive strength of an ultra-thin copper foil and a resin layer excellent. In addition, a main component means the most component, Preferably it is a component contained 50 mol% or more.

On the other hand, in the low thermally expandable resin layer, at least one selected from 4,4'-diamino-2,2'-dimethylbiphenyl (DADMB) and 4,4'-diamino-2'-methoxybenzanilide (MABA) As one type of diamine component and an acid anhydride component, pyromellitic anhydride (PMDA), 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3', 4,4 ' At least one acid anhydride component selected from -benzophenonetetracarboxylic dianhydride (BTDA), 3,3 ', 4,4'-diphenylsulfontetracarboxylic dianhydride (DSDA) as each main component It is preferable to use the polyimide precursor resin solution obtained by making these react. In addition, about the diamine component and the acid anhydride component of a high thermally expansible resin layer and a low thermally expansible resin layer, respectively, only 1 type may be used, and 2 or more types may be used together. In addition, a main component means the most component, Preferably it is a component contained 50 mol% or more.

Examples of the solvent used in the reaction include N, N-dimethylacetamide (DMAc), n-methylpyrrolidinone, 2-butanone, diglyme, xylene, and the like. It can also be used in combination of 2 or more types.

Coating of the resin solution onto the ultrathin copper foil can be performed by applying a known method, and a roll coater, a die coater, and a bar coater are often used industrially. It is necessary to make coating thickness uniform, and it is preferable to make thickness variation of the resin layer after heat processing into the range of ± 1.5 micrometers. After the resin solution is coated on the ultrathin copper foil, it is dried and heat treated to remove the solvent of the resin solution. The heat treatment may be a treatment performed at a temperature of 130 ° C. or higher, and the drying may be further performed here. Advantageously, heat treatment results in reactions such as imidization and property modification of the resin. For example, when polyimide precursor resin is used for the resin solution, heat treatment is performed for imidization. The curl of the multilayer laminate obtained by changing the temperature conditions of the heat treatment for imidization may be changed. Here, when making a resin layer into a multilayer, after coating and drying are repeated, you may heat-process collectively.

In the present invention, in this way, a multilayer laminate having a uniform resin layer formed on the ultrathin copper foil of the ultrathin copper foil with a heat resistant carrier, and then peeling the carrier, the flexible copper clad laminated substrate for the purpose of being composed of the resin layer and the ultrathin copper foil. When the carrier is peeled off, a stress is applied to the flexible copper clad laminate that is peeled off from the carrier. If the material was designed and manufactured without considering the stress applied in this peeling step, curling occurred due to the stress applied during peeling. In other words, even if the product after the resin layer formation is flat, a phenomenon occurs in which curl to the side opposite to the carrier side occurs when the carrier is peeled off.

Therefore, in the present invention, a flexible copper clad laminated substrate made of a flat resin layer and an ultrathin copper foil after peeling is generated by generating a force for curling the carrier side to the inner side with respect to the multilayer laminate before peeling, and then peeling the carrier. Can be prepared. The force which curls a carrier side inward can be quantified using the multilayer laminated body before a peeling process. Specifically, it is possible to prepare and measure the sample (50x50mm square) of the multilayer structure before the peeling process in which the resin layer was formed in the ultra-thin copper foil with heat resistant carrier foil. It is preferable to control the curl amount C of the multilayer laminate before the peeling step in the range of -1 mm ≤ C ≤-10 mm, and more preferably in the range of -2 mm ≤ C ≤-8 mm. If the control range C of the amount of curl before this peeling step is larger than -1 mm, the suppression of curl of the flexible copper clad laminate after peeling becomes insufficient, and if smaller than -10 mm, the curl formed in advance remains. In other words, by forming some curl on the opposite side to it in advance so that the minimum curl which arises at the time of carrier peeling may be eliminated, it can be set as the product which the curl after carrier peeling falls in the range of +/- 3mm.

As a means of imparting a force for curling the support (carrier) side inward before the peeling step, there are several considerations, one of which is before the peeling step by changing the heat treatment conditions to the resin solution coated on the ultrathin copper foil and heat treated. A force for curling the carrier side inward can be generated for the multilayer laminate. More specifically, in the case where a polyimide precursor is used in the resin solution, the curling amount can be controlled to some extent by changing the curing temperature among the curing conditions, but the curling conditions are not generated using a copper foil of 10 to 30 µm. Rather, it becomes possible to generate | occur | produce the force which curls a carrier side inward by making hardening start temperature 5-20 degreeC high. In addition, in this specification, the case where curl generate | occur | produces inward on the resin layer side is shown as positive (+), and the case where the force which curls inward | carrier side is generated is shown by minus (-). That is, "-1mm <= C <=-10mm" mentioned above means the state which controlled the stress to the extent that curl generate | occur | produces in the range of 10mm-1mm in concave carrier side.

Moreover, by forming the following resin layer, the multilayer laminated body before a peeling process can also be curled with a support body (carrier) side inside. That is, a high thermal expansion resin layer having a thermal expansion coefficient of 20 × 10 ⁻⁶ (l / K) or more, a low expansion resin layer having a thermal expansion coefficient of less than 20 × 10 ⁻⁶ (l / K), and a thermal expansion coefficient 20 × 10 ^-6 (l / K) or more and a high heat-expandable resin layer is the number of sequentially formed layers, the range of the resin layer has a thermal expansion coefficient of the entire ^{15 × 10 -6 ~25 × 10 -6} , preferably 15 × ^10-6 range of ^{~23 × 10 -6 (l / K} ), and more preferably to a range of ^{15 × 10 -6 ~20 × 10 -6} (l / K). The ratio (t _a / t _c ) of the thickness t _a of the high thermal expansion resin layer on the ultrathin copper foil side to the thickness t _c of the high thermal expansion resin layer of the outermost layer is 0.25 to 0.95, and the total thickness of the resin layer is It is set to 10-50 micrometers.

When the thickness ratio t _a / t _c is lower than 0.25, the flexible copper clad laminate after peeling the carrier curls to the ultrathin copper foil side, and conversely, when the thickness ratio t _a / t _c is higher than 0.95, the carrier After peeling, it curls to the resin layer side and the flatness of a board | substrate deteriorates. Further, the viewpoint of adjusting the range of the thickness t _b when inserting the low thermal expansion properties of the resin layer (1b) on the consideration, the overall coefficient of thermal expansion of the resin layer is ^{15 × 10 -6 ~25 × 10 -6} (l / K) Is preferably such that the ratio [(t _a + t _c ) / t _b ] determined from the thickness of the resin layer is 0.1 ≦ [(t _a + t _c ) / t _b ] ≦ 0.5. On the other hand, when the total thickness of the resin layer is smaller than 10 µm, there is a possibility that the electrical insulation cannot be secured, and the handling property is lowered, which may make handling in the manufacturing process difficult. On the contrary, when larger than 50 micrometers, circuit wiring may break at the time of bending in applications, such as COF, and it may become impractical.

In the present invention, the support is peeled off from the multilayer laminate to obtain a flexible copper clad laminated substrate made of an ultrathin copper foil and a resin layer, wherein the ultrathin copper foil and the resin layer are laminated and separated from the carrier in an integrated state. The separated laminated body is a flexible copper clad laminated substrate whose copper foil is an ultrathin copper foil. When the multilayer laminate is separated into a flexible copper clad laminated substrate composed of a carrier, ultrathin copper foil and a resin layer, the preferred peeling angle θ of the carrier with respect to the flexible copper clad laminated substrate is 90 ° or more and a range of 180 ° ± 50 ° Preferably, more preferably, in the peeling portion of the carrier and the flexible copper clad laminated substrate, the flexible copper sheet peeled off when the flexible copper clad laminated substrate to be peeled off is advanced in a range of ± 20 ° with respect to the method of advancing the multilayer laminate. It is preferable to peel the peeling angle θ, which is an angle formed between the laminated substrate and the carrier, in the range of 140 ° ≦ θ ≦ 180 °. Here, the "advanced angle of the flexible copper clad laminated board separated from the multilayered laminate" in the case of "moving the flexible copper clad laminated board to be peeled off in the range of ± 20 ° with respect to the method of advancing the multilayer laminate in the peeling site". Is a value indicated when the advancing direction before separation is 0 °, and becomes 0 ° when the flexible copper-clad laminate is linearly advanced before and after peeling. By setting the peeling angle to an appropriate range as described above, it is advantageous for suppressing curl after peeling.

The flexible copper clad laminated substrate obtained by the present invention may be a single-sided flexible copper clad laminated substrate having ultra-thin copper foil on one side of the resin layer, or may be a double-sided flexible copper clad laminated substrate having ultra-thin copper foil on both sides of the resin layer.

In order to make a double-sided flexible copper clad laminated substrate, after manufacturing a single-sided flexible copper clad laminated substrate, it can manufacture by preparing a new copper foil and the ultra-thin copper foil with a heat resistant carrier, and heat-pressing. By using the ultra-thin copper foil with a heat resistant carrier, the flexible copper clad laminated substrate which has an ultra-thin copper foil can be manufactured.

In the present invention, the curling force of the flexible copper clad laminate is controlled within a predetermined range by generating a force for curling the carrier side inward with respect to the multilayer laminate before carrier peeling, and then peeling the carrier. It can measure by the measuring method as described in an Example. In other words, a sample having a size of 50 x 50 mm (square) is obtained from a flexible copper clad laminate produced by appropriate means, and the curl amount is suppressed to within ± 3 mm in the present invention. If the amount of curl is not within this range, problems such as poor workability may occur during circuit processing of the flexible printed circuit board.

In the flexible copper-clad laminate produced by the present invention, the adhesive strength between the ultra-thin copper foil and the resin layer is preferably 0.8 kN / m or more, and the ultra-thin copper foil and the resin layer after heat treatment at 150 ° C. for 168 hours in air. It is preferable that the adhesive strength of is 80% or more of the initial adhesive strength before heat treatment. In addition, a better flexible copper clad laminate can be produced by setting the peel strength between the ultrathin copper foil and the carrier after the resin layer is 3 to 100 N / m.

Effect of the Invention

According to the present invention, in the method for producing a flexible copper clad laminate using an ultrathin copper foil with a heat resistant carrier, the occurrence of curl generated when the carrier is peeled off can be suppressed. A flexible copper clad laminated substrate having excellent properties can be obtained. Moreover, the flexible copper clad laminated board manufactured is obtained by coating a resin solution on an ultrathin copper foil, and is excellent also in the adhesiveness and heat resistance reliability of an ultrathin copper foil and a resin layer. Moreover, in the manufacturing method of the flexible copper clad laminated board of this invention, since the copper foil thickness can be arbitrarily set to 0.1-10 micrometers, the flexible copper clad laminated board useful also in a subtractive method or a semiadditive process can be manufactured.

1 is a cross-sectional view of a multilayer laminate before peeling.

2 is a cross-sectional view of the flexible copper clad laminate after peeling.

<Description of the code>

1: Resin layer 1a: 1st layer resin layer

1b: 2nd layer resin layer 1c: 3rd layer resin layer

2: ultrathin copper foil 3: release layer

4: carrier 5: multilayer laminate

6: Flexible Copper Clad Substrate

The present invention will be explained with reference to the drawings. 1 is a cross-sectional view showing the layer structure of the multilayer laminate 5. The ultra-thin copper foil with a heat resistant carrier consists of the carrier 4, the peeling layer 3, and the ultra-thin copper foil 2. The resin layers 1a, 1b, and 1c are laminated on this. As shown in FIG. 1, this multilayer laminated body 5 curls as the carrier 4 side is inward.

2 is a cross-sectional view showing the layer structure of the flexible copper clad laminated substrate 6 obtained by peeling the carrier 4 from the multilayer laminate. The flexible copper clad laminated substrate 6 is composed of an ultrathin copper foil 2 and a resin layer 1 composed of resin layers 1a, 1b and 1c. This flexible copper clad laminated substrate 6 is not curled as shown in FIG.

Example

EMBODIMENT OF THE INVENTION Hereinafter, although this invention is demonstrated concretely based on an Example and a comparative example, of course, this invention is not limited to this.

Synthesis Example 1

29.13 g (0.071 mol) of BAPP was dissolved in 294 g of DMAc. Next, 3.225 g (0.011 mol) of BPDA and 13.55 g (0.062 mol) PMDA were added. Thereafter, stirring was continued for about 3 hours to conduct a polymerization reaction to obtain a 35-poise (25 ° C) polyimide precursor resin liquid a. Moreover, when this obtained polyimide precursor resin liquid a is coated on copper foil, it is dried at 130 degreeC for 5 minutes, after that, it heats up to 360 degreeC over 15 minutes, complete | finishes imidization, and is obtained when a polyimide film was produced. The coefficient of thermal expansion of the film was measured and found to be 55 × 10 ⁻⁶ / K.

Synthesis Example 2

In 3.076 kg of DMAc, 203.22 g (0.957 mol) of DADMB and 31.10 g (0.106 mol) of 1,3-BAB were dissolved. Next, 61.96 g (0.211 mol) of BPDA and 183.73 g (0.842 mol) of PMDA were added. Thereafter, stirring was continued for about 4 hours to carry out a polymerization reaction, to obtain a polyimide precursor resin liquid b of 250 poise (25 ° C). In addition, the thermal expansion coefficient in the case of producing a polyimide film similarly to the synthesis example 1 using this obtained polyimide precursor resin liquid b was ^{15x10 <-6>} / K.

Example 1

Coating the resin liquid a of Synthesis Example 1 on an ultrathin copper foil having a heat resistant carrier foil (YSNAP-3B manufactured by Nippon Denkai, 18 μm carrier copper thickness, 3 μm ultrathin copper foil thickness, peeling layer thickness of about 100 nm). After drying at 130 ° C. for 5 minutes to form a resin layer 1a, the resin liquid b of Synthesis Example 2 was coated, dried at 130 ° C. for 10 minutes to form 1b, and the resin liquid of Synthesis Example 1 was formed on the resin layer. a was coated and dried at 130 ° C. for 5 minutes to form a resin layer 1c. Then, it heated up to 360 degreeC over 15 minutes, and completed imidation, and formed the resin layer 1 which has a multilayer polyimide resin layer (1a: 2micrometer / 1b: 20micrometer / 1c: 3micrometer). Here, in the stage of imidation reaction, the initial imidation conditions are 140 degreeC and 4 minutes, the thermal expansion coefficient of a multilayer polyimide resin layer (resin layer 1) is reduced to 19 ppm / K, and a carrier is carried out before a peeling process. (Carrier copper foil) is a multi-layer laminate (5) curled so as to be the inner side, the carrier at an angle of 180 ° with respect to the flexible copper clad laminated substrate 6 consisting of ultra-thin copper foil (2) and the resin layer (1) in the peeling step The foil was peeled off to obtain a flexible copper clad laminated substrate 6.

With respect to the flexible copper clad laminate 6 obtained by the above method, the curl of the multilayered laminate 5 before carrier peeling, the curl, peel strength, and heat resistance of the flexible copper clad laminate 6 after peeling were measured. Measured. Table 1 shows the measurement results. After peeling, the determination was made that the curl of the flexible copper clad laminated board 6 was within ± 3 mm, the peel strength was 0.8 kN / m or more, and the heat resistance retention rate was 80% or more. It was set as.

[Measurement of curl (curl before peeling) of multilayer laminate]

Prepare the multilayer laminated body 5 before the peeling process a little larger than 50x50mm in which the resin layer was formed in the ultra-thin copper foil with heat resistant carrier foil, and the multilayer laminated body 5 used for a measurement will be 50x50mm in size. The other conductor portion (part outside 50 × 50 mm) was cut after etching with ferric chloride solution. It dried at 100 degreeC for 10 minutes, left still for 24 hours in the atmosphere of the temperature of 25 degreeC, and 50% of humidity, and set it so that the lower side might become convex on a horizontal board, and measured the average value of the height of four corners. The time when the resin layer side became convex was made into-, and the time when the carrier side became convex was made into +.

[Measurement of curl (curl after peeling) of flexible copper clad laminate]

Similar to the measurement of the curl amount of the multilayer laminate 5 before peeling, the other conductor portion is cut after etching with a ferric chloride solution so that the multilayer laminate 5 has a size of 50 mm x 50 mm, and cut at 100 ° C for 10 minutes. Dried. Thereafter, the carrier foil was peeled off with respect to the flexible copper clad laminated substrate 6 composed of the ultra-thin copper foil 2 and the resin layer 1 so that the peel angle was 180 °, thereby obtaining the flexible copper clad laminated substrate 6. The obtained flexible copper clad laminated board 6 after peeling was left to stand for 24 hours in an atmosphere of temperature 25 ° C and a humidity of 50%, and the lower side was convex, and the average value of the four corners was measured. The time when the resin layer side became convex was set to-, and the time when the ultra-thin copper foil side became convex was made into +.

[Measurement of Peel Strength]

The electrolytic copper plating was performed on the ultrathin copper foil on the flexible copper clad laminated substrate 6 after the carrier foil was peeled off so that the total thickness of the copper including the ultrathin copper foil was 8 µm for easy measurement. The copper side was patterned in a straight shape with a width of 1 mm to form a flexible circuit board for testing, and a tensilon tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.) was used, and the resin side was fixed to the stainless steel plate by double-sided tape. And copper was peeled and calculated | required at the speed | rate of 50 mm / min in a 90 degree direction.

[Measurement of heat retention rate]

The same test flexible circuit board as used in the measurement of the peel strength was prepared, and a heat resistance test for 168 hours in air at 150 ° C. was performed to calculate the peel strength retention before and after the heat test.

[Measurement method of thermal expansion coefficient]

It carried out by thermomechanical analysis in the tension mode using the thermomechanical analyzer (made by Seiko Instruments Co., Ltd.), and calculated and calculated | required the average coefficient of thermal expansion in the range of 250 degreeC to 100 degreeC.

Table 1 shows each measurement result.

EXAMPLE 2 AND COMPARATIVE EXAMPLES 1-3

By changing the curing conditions of the coated polyimide precursor resin solution, the flexible copper-clad laminate 6 was prepared in the same manner as in Example 1 except that the thermal expansion coefficient of the resin layer was changed to change the curl of the multilayer laminate before peeling. The preparation was evaluated. Table 1 shows the results of characteristics of initial curing at the time of curing and obtained flexible copper clad laminated substrates.

(Initial) curing temperature (℃) Curl Before Peeling (mm) Curl after Peeling (mm) Coefficient of thermal expansion (ppm / K) Peel Strength (kN / m) Heat retention rate (%) Judgment Example 1 140 -3.8 +0.9 19.0 1.0 80 ○ Example 2 138 -4.5 +0.2 18.8 1.0 80 ○ Comparative Example 1 135 -10.5 -7.7 18.1 1.0 80 × Comparative Example 2 130 -0.4 +6.2 20.8 1.0 80 × Comparative Example 3 150 +2.8 +7.4 22.2 1.0 80 ×

As a result of the evaluation, Examples 1 and 2 were able to make the curl of the flexible copper clad laminated board after carrier peeling into a very small value. On the other hand, in the comparative example 1, the curl which made the carrier inward before peeling was too big, and in the comparative example 2, the curl which made the carrier inward before peeling was too small, and the curl after peeling became large and it was defect. In the comparative example 3, since the curl before carrier peeling was a curl which made the carrier outward, the curl after peeling became larger and it was defect.

Example 3

Resin liquid a of Synthesis example 1 on the ultra-thin copper foil 5 of ultra-thin copper foils with heat-resistant carrier foil (YSNAP-1B by Nippon Denkai: 18 micrometers of carrier copper thickness, 1 micrometer of ultra-thin copper foil thickness, peeling layer thickness about 100 nm). After coating, drying at 130 ° C for 5 minutes to form a resin layer 1a, coating the resin solution b of Synthesis Example 2, drying at 130 ° C for 10 minutes to form a resin layer 1b, and The resin liquid a of the synthesis example 1 was coated on the resin layer 1b, and it dried at 130 degreeC for 5 minutes, and formed the resin layer 1c. And, subjected to imidization reaction by temperature increase over 15 minutes to 360 ℃, the resin layer (1a) of the thickness t (high heat-expandable resin layer) is _a 1.5㎛, the thickness t _b of the resin layer (1b) (low thermal expansion resin layer) the 18.0㎛, and the resin layer (1c) may have a thickness of t _c (high heat-expandable resin layer) comprising the 5.8㎛ to form a resin layer (1), to obtain a multilayer laminate (5). The total thickness of the resin layer 1 is 25.3 μm, and the ratio t _a / t _c of the thickness t _a of the resin layer 1a and the thickness t _c of the resin layer 1c is 0.26, (t _a + t _c ) / t _b was 0.41. Moreover, the thermal expansion coefficient of the whole resin layer 1 was 18.5x10 <^-6> (l / K).

Next, the film curl and the curl after carrier copper foil peeling were measured about the multilayer laminated body 5 obtained above. Table 2 shows the measurement results. In addition, the measurement of the film curl used the method shown below, and evaluated it similarly to Example 1 except the other.

[Measurement method of film curl]

The ultra-thin copper foil with heat-resistant carrier foil was etched in full with ferric chloride solution to produce a polyimide film from the multilayer laminate 5, cut into a size of 50 mm x 50 mm, dried at 100 ° C. for 10 minutes, temperature 25 ° C., After standing for 24 hours in an atmosphere of 50% humidity, the lower side was convex, and the average value of the four corners was measured. Here, the time when the outermost resin layer 1c becomes convex is set to +, and the time when the resin layer 1a which is in contact with the conductor becomes convex is set to-.

EXAMPLE 4 AND COMPARATIVE EXAMPLES 4-8

The resin layer 1a as shown in Table 2 by fixing the thickness of the resin layer 1b to 18.0 micrometers, and changing the application amount of the resin liquid at the time of forming the resin layer 1a and the resin layer 1c, and The multilayer laminated body 5 which changed the resin layer thickness of the resin layer 1c was obtained. In addition, the linear expansion coefficient of the whole resin layer 1 is a ratio of the sum (t _a + t _c ) of the resin layer thicknesses of the resin layers 1a and 1c to the thickness t _b of the resin layer 1b [(t _a + t _c ) / t _b ] and the temperature increase time to 360 degreeC at the time of imidization were adjusted by changing. By increasing the temperature raising time, the coefficient of thermal expansion can be lowered, and conversely, it can be adjusted by increasing the coefficient of thermal expansion. Otherwise, the multilayer laminated body 5 was created by the method similar to Example 3, the film curl, the curl after carrier copper foil peeling, and the coefficient of thermal expansion were measured. Table 2 shows the measurement results.

t _a / t _c (t _a + t _c ) / t _b Film curl (mm) Curl Before Peeling (mm) Coefficient of thermal expansion (ppm / K) Curl after peeling (mm) Peel Strength (kN / m) Heat retention rate (%) Judgment Example 3 0.26 0.41 -2 -3 18.5 +1 1.0 80 ○ Example 4 0.50 0.33 0 -5 20.8 0 1.0 80 ○ Comparative Example 4 0.16 0.37 Barrel shape +9 21.3 +11 1.0 80 × Comparative Example 5 1.44 0.46 Barrel shape -16 23.3 -6 1.0 80 × Comparative Example 6 0.30 0.29 -2 +12 14.5 +15 1.0 80 × Comparative Example 7 0.75 0.63 -2 Barrel shape 31.0 Barrel shape 1.0 80 × Comparative Example 8 0 0.22 0 -6 15.0 -One 0.1 0 ×

As a result of evaluation, since Examples 3 and 4 had few film curls, and also the thermal expansion coefficient became a value close to the thermal expansion coefficient of copper, it was possible to make the curl after carrier foil peeling into a very small value.

Claims (10)

A resin solution is coated on the ultrathin copper foil of the ultrathin copper foil with the heat resistant carrier having the ultrathin copper foil formed on the carrier via a peeling layer, and dried and heat treated to provide one or more layers of resin layers on the ultrathin copper foil with the heat resistant carrier. A method of manufacturing a flexible copper clad laminated substrate comprising a resin layer and an ultrathin copper foil, after which the carrier is peeled off to form a multilayer laminate formed thereon, wherein the carrier side is curled inward with respect to the multilayer laminate before peeling. A method for producing a flexible copper clad laminate, characterized in that a flexible copper clad laminated substrate is produced which generates a force and subsequently suppresses the amount of curl measured by a 50 × 50 mm sample to within ± 3 mm by peeling the carrier. The resin layer formed on the ultra-thin copper foil according to claim 1, wherein the resin layer formed on the ultrathin copper foil has at least one high thermal expansion resin layer having a thermal expansion coefficient of 20 × 10 ⁻⁶ (l / K) or higher and a thermal expansion coefficient of 20 × 10 ⁻⁶ (l / It is a polyimide resin layer which has at least 1 layer of low-expansion resin layer which is less than K), and the thermal expansion coefficient of the whole resin layer exists in the range of 15 * 10 <^-6> -25 * 10 <^-6> (l / K). Method for manufacturing a flexible copper clad laminated substrate. The ultra-expandable resin layer having a thermal expansion coefficient of 20 × 10 ⁻⁶ (l / K) or more on the ultrathin copper foil, a low expansion resin layer having a thermal expansion coefficient of less than 20 × 10 ⁻⁶ (l / K), And a thermally expandable resin layer having a thermal expansion coefficient of 20 × 10 ⁻⁶ (l / K) or more, which is sequentially laminated to form a resin layer, wherein the thickness t _a of the high thermal expansion resin layer on the ultrathin copper foil side and the high thermal expansion resin layer of the outermost layer are formed. the ratio of the thickness _{t c (t a / t c} ) is 0.25 to 0.95, also, can manufacturing method of the flexible copper-clad laminate board, it characterized in that the total thickness of the resin layer is 10~50㎛. The high thermally expandable resin layer on the ultra-thin copper foil side is one kind selected from 2,2'-bis [4- (4-aminophenoxy) phenyl] propane or 4,4'-diaminodiphenyl ether. Selected from the above diamine component, pyromellitic anhydride, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, and 3,3', 4,4'-benzophenonetetracarboxylic dianhydride It is a polyimide resin obtained by making 1 or more types of acid anhydride components into each main component, and reacting these, and a low thermally expansible resin layer is 4,4'- diamino-2,2'- dimethyl biphenyl or 2-methoxy- At least one diamine component selected from 4,4'-diaminobenzanilide, and at least one acid anhydride component selected from pyromellitic anhydride or 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride It is a polyimide resin obtained by making each main component and reacting these, The agent of the flexible copper clad laminated board characterized by the above-mentioned. Method. The ultra-thin copper foil of the ultra-thin copper foil with a heat resistant carrier is 0.1-10 micrometers, carrier is a metal or resin, The thickness is 5-100 micrometers, The flexible copper field of Claim 1 or 2 characterized by the above-mentioned. Method of manufacturing a laminated substrate. A multilayer of a resin solution formed on an ultrathin copper foil with a heat resistant carrier by coating a resin solution on an ultrathin copper foil of an ultrathin copper foil with a heat resistant carrier having an ultrathin copper foil formed thereon through a peeling layer on a carrier. It is a laminated body and a resin layer is a high thermal expansion resin layer of 20 * 10 <^-6> (l / K) or more of thermal expansion coefficient 20 or less, and a low expansion resin layer of less than 20 * 10 <^-6> (l / K) of thermal expansion coefficient in order from an ultrathin copper foil. , And a high thermal expansion resin layer having a thermal expansion coefficient of 20 × 10 ⁻⁶ (l / K) or higher, sequentially laminated, and having a thermal expansion coefficient of 15 × 10 ^{−6 to} 25 × 10 ⁻⁶ (l / K), Moreover, the ratio (t _a / t _c ) of the thickness t _a of the high thermal expansion resin layer on the ultrathin copper foil side to the thickness t _c of the high thermal expansion resin layer of the outermost layer is 0.25-0.95, and the total thickness of the resin layer is 10-95. It is 50 micrometers, The multilayer laminated body characterized by the above-mentioned. The high thermally expandable resin layer on the ultrathin copper foil side is one kind selected from 2,2'-bis [4- (4-aminophenoxy) phenyl] propane or 4,4'-diaminodiphenyl ether. Selected from the above diamine component, pyromellitic anhydride, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, and 3,3', 4,4'-benzophenonetetracarboxylic dianhydride It is a polyimide resin obtained by making 1 or more types of acid anhydride components into each main component, and reacting these, and a low thermally expansible resin layer is 4,4'- diamino-2,2'- dimethyl biphenyl or 2-methoxy- At least one diamine component selected from 4,4'-diaminobenzanilide, and at least one acid anhydride component selected from pyromellitic anhydride or 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride It is a polyimide resin obtained by making each main component and reacting these, The multilayer laminated body characterized by the above-mentioned. The multilayer laminated body of Claim 6 or 7 whose adhesive strength of an ultra-thin copper foil and a resin layer is 0.8 kN / m or more. The adhesive strength of the ultra-thin copper foil and resin layer after heat-processing in air at 150 degreeC for 168 hours is 80% or more of the initial adhesive strength before heat processing in any one of Claims 6-8. It has a multilayer laminated body characterized by the above-mentioned. The ultra-thin copper foil of the ultra-thin copper foil with a heat resistant carrier is 0.1-10 micrometers, a carrier is a metal or resin, and the thickness is 5-100 micrometers in any one of Claims 6-9. Multilayered laminate made of.

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