JP2015010274A - Copper foil with carrier, production method of copper foil with carrier, printed wiring board, printed circuit board, copper-clad laminate sheet and production method of printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copper foil with a carrier in which before a lamination step to an insulation substrate, the adhesion force between a carrier and an extra thin copper layer is high, and while after the lamination step to the insulation substrate, the adhesiveness between the carrier and the extra thin copper layer is lowered, the carrier and the extra thin copper layer can be easily peeled and generation of a pinhole on an extra thin copper layer side surface is favorably suppressed.SOLUTION: There is provided a copper foil with a carrier which comprises a carrier, an intermediate layer laminated on the carrier and an extra thin copper layer laminated on the intermediate layer, where the intermediate layer is constituted of a molybdenum-nickel alloy or a molybdenum-cobalt alloy or a molybdenum-iron alloy, and when a cross-section of the copper foil carrier/interlayer/ultrathin copper layer is examined by STEM line analysis over a length of 50 to 1000 nm which includes all of the layers in this order, the maximum of the molybdenum concentration is 1 to 70 mass%.

Description

  The present invention relates to a carrier-attached copper foil, a method for producing the same, a printed wiring board, a printed circuit board, a copper-clad laminate, and a method for producing a printed wiring board.

  Printed wiring boards have made great progress over the last half century and are now used in almost all electronic devices. In recent years, with the increasing demand for miniaturization and high performance of electronic devices, higher density mounting of components and higher frequency of signals have progressed, and conductor patterns have become finer (fine pitch) and printed circuit boards. For example, when an IC chip is mounted on a printed wiring board, a fine pitch of L / S = 20 μm / 20 μm or less is required.

  A printed wiring board is first manufactured as a copper clad laminate in which an insulating substrate mainly composed of a copper foil and a glass epoxy substrate, a BT resin, a polyimide film, or the like is bonded. Bonding is performed by laminating an insulating substrate and a copper foil and applying heat and pressure (laminating method), or by applying a varnish that is a precursor of an insulating substrate material to a surface having a coating layer of copper foil, A heating / curing method (casting method) is used.

  Along with the fine pitch, the thickness of the copper foil used for the copper clad laminate is also 9 μm, and further, 5 μm or less. However, when the foil thickness is 9 μm or less, the handleability when forming a copper clad laminate by the above-described lamination method or casting method is extremely deteriorated. Therefore, a copper foil with a carrier has appeared, in which a thick metal foil is used as a carrier, and an ultrathin copper layer is formed on the metal foil via a release layer. A general method of using a copper foil with a carrier is to peel the carrier through a release layer after the surface of the ultrathin copper layer is bonded to an insulating substrate and thermocompression bonded.

  As a technique related to a copper foil with a carrier, for example, in Patent Document 1, a diffusion prevention layer, a release layer, and an electrolytic copper plating are formed in this order on the surface of a carrier, and a Cr or Cr hydrated oxide layer is formed as a release layer A method for maintaining good peelability after hot pressing by using a simple substance or an alloy of Ni, Co, Fe, Cr, Mo, Ta, Cu, Al, P as a diffusion preventing layer is disclosed.

  Further, it is known that the release layer is formed of Cr, Ni, Co, Fe, Mo, Ti, W, P, alloys thereof, or hydrates thereof. Furthermore, Patent Documents 2 and 3 describe that it is effective to provide Ni, Fe or an alloy layer thereof as a base of the release layer in order to stabilize the peelability in a high temperature use environment such as a hot press. Has been.

JP 2006-022406 A JP 2010-006071 A JP 2007-007937 A

  In copper foil with a carrier, it is necessary to avoid the peeling of the ultrathin copper layer from the carrier before the lamination process on the insulating substrate, while the ultrathin copper layer from the carrier is removed after the lamination process to the insulating substrate. Must be peelable. In addition, in the copper foil with a carrier, the presence of pinholes on the surface of the ultrathin copper layer is not preferable because it leads to poor performance of the printed wiring board.

  With respect to these points, the prior art has not been sufficiently studied, and there is still room for improvement. Therefore, an object of the present invention is to provide a copper foil with a carrier that can be peeled off after a lamination process on an insulating substrate, while the ultrathin copper layer does not peel off from the carrier before the lamination process on the insulating substrate. . Another object of the present invention is to provide a carrier-attached copper foil in which the generation of pinholes on the ultrathin copper layer side surface is suppressed.

  In order to achieve the above-mentioned object, the present inventor has conducted extensive research and uses copper foil as a carrier, and forms an intermediate layer between the ultrathin copper layer and the carrier, and this intermediate layer is formed of a molybdenum-nickel alloy. Or composed of molybdenum-cobalt alloy or molybdenum-iron alloy, controlling the adhesion amount of nickel, molybdenum and cobalt, and controlling the maximum molybdenum concentration in the copper foil with carrier are extremely effective. I found out.

The present invention has been completed based on the above knowledge, and in one aspect, a carrier-attached copper foil comprising a carrier, an intermediate layer laminated on the carrier, and an ultrathin copper layer laminated on the intermediate layer The intermediate layer is made of a molybdenum-nickel alloy, a molybdenum-cobalt alloy, or a molybdenum-iron alloy, and the intermediate layer has a molybdenum adhesion amount of 50 to 10,000 μg / dm ² . When nickel is included, the adhesion amount of nickel is 50 to 40,000 μg / dm ² , when the intermediate layer includes cobalt, the adhesion amount of cobalt is 50 to 10,000 μg / dm ² , and when the intermediate layer includes iron, the adhesion amount of iron is 50 to 10000 μg / dm ² , 50 to 1000 nm long STEM in the range including all of them in this order from the cross section of the carrier / intermediate layer / ultra thin copper layer When the line analysis is performed, the carrier-attached copper foil has a maximum molybdenum concentration of 1 to 70% by mass.

  In another aspect of the present invention, an intermediate layer is formed by forming a layer containing any one or more of a molybdenum-cobalt alloy, a molybdenum-nickel alloy, and a molybdenum-iron alloy on a carrier by dry plating or electroplating. And a process for forming an ultrathin copper layer by electrolytic plating on the intermediate layer.

  In still another aspect, the present invention is a printed wiring board manufactured using the carrier-attached copper foil of the present invention.

  In still another aspect, the present invention is a printed circuit board manufactured using the carrier-attached copper foil of the present invention.

  In yet another aspect, the present invention is a copper clad laminate produced using the carrier-attached copper foil of the present invention.

  In yet another aspect of the present invention, the step of preparing the copper foil with carrier and the insulating substrate of the present invention, the step of laminating the copper foil with carrier and the insulating substrate, the copper foil with carrier and the insulating substrate, After the lamination, a copper-clad laminate is formed through a step of peeling the carrier of the copper foil with carrier, and then the circuit is formed by any of the semi-additive method, the subtractive method, the partial additive method, or the modified semi-additive method. It is a manufacturing method of a printed wiring board including the process of forming.

  The copper foil with a carrier according to the present invention has high adhesion between the carrier and the ultrathin copper layer before the lamination process to the insulating substrate, while the carrier and the ultrathin copper layer after the lamination process to the insulation substrate. Adhesiveness is lowered, it can be easily peeled off at the carrier / ultra-thin copper layer interface, and the occurrence of pinholes on the surface of the ultra-thin copper layer can be satisfactorily suppressed.

AC is a schematic diagram of the wiring board cross section in the process to circuit plating and the resist removal based on the specific example of the manufacturing method of the printed wiring board using the copper foil with a carrier of this invention. DF is a schematic diagram of a cross section of a wiring board in a process from lamination of a resin and copper foil with a second layer carrier to laser drilling according to a specific example of a method for producing a printed wiring board using a copper foil with a carrier of the present invention. It is. GI is a schematic diagram of the wiring board cross section in the process from the via fill formation to the first layer carrier peeling according to a specific example of the method for manufacturing a printed wiring board using the carrier-attached copper foil of the present invention. J to K are schematic views of a cross section of a wiring board in steps from flash etching to bump / copper pillar formation according to a specific example of a method of manufacturing a printed wiring board using the carrier-attached copper foil of the present invention. It is a STEM line analysis result after the board | substrate bonding of Example 5. FIG. It is a STEM line analysis result after the board | substrate bonding of the comparative example 3. FIG.

<1. Career>
A copper foil is used as a carrier that can be used in the present invention. The carrier is typically provided in the form of rolled copper foil or electrolytic copper foil. In general, the electrolytic copper foil is produced by electrolytic deposition of copper from a copper sulfate plating bath onto a drum of titanium or stainless steel, and the rolled copper foil is produced by repeating plastic working and heat treatment with a rolling roll. In addition to high-purity copper such as tough pitch copper and oxygen-free copper, the copper foil material is, for example, Sn-containing copper, Ag-containing copper, copper alloy added with Cr, Zr, Mg, etc., and Corson-based added with Ni, Si, etc. Copper alloys such as copper alloys can also be used. In addition, when the term “copper foil” is used alone in this specification, a copper alloy foil is also included.

  The thickness of the carrier that can be used in the present invention is not particularly limited, but may be appropriately adjusted to a thickness suitable for serving as a carrier, for example, 12 μm or more. However, if it is too thick, the production cost becomes high, so generally it is preferably 35 μm or less. Accordingly, the thickness of the carrier is typically 12-70 μm, more typically 18-35 μm.

<2. Intermediate layer>
An intermediate layer is provided on the copper foil carrier. The intermediate layer is made of a molybdenum-nickel alloy, a molybdenum-cobalt alloy, or a molybdenum-iron alloy. When the intermediate layer contains molybdenum, when the ultrathin copper layer is peeled off, the intermediate layer is favorably peeled off at the interface with the ultrathin copper layer.
When using electrolytic copper foil as a carrier, it is preferable to provide an intermediate layer on the shiny surface from the viewpoint of reducing pinholes.

  The molybdenum-nickel alloy, molybdenum-cobalt alloy, or molybdenum-iron alloy layer that constitutes the intermediate layer is thinly present at the interface of the ultrathin copper layer. While the layer does not peel off, it is preferable for obtaining the characteristic that the ultrathin copper layer can be peeled off from the carrier after the lamination process on the insulating substrate.

In the intermediate layer, the adhesion amount of molybdenum in the intermediate layer is 50 to 10,000 μg / dm ^{2. When} the intermediate layer contains nickel, the adhesion amount of nickel is 50 to 40,000 μg / dm ² , and when the intermediate layer contains cobalt, the adhesion of cobalt. The amount is 50 to 10000 μg / dm ² , and when the intermediate layer contains iron, the amount of iron attached is 50 to 10,000 μg / dm ² . Although the amount of pinholes tends to increase as the amount of molybdenum increases, the number of pinholes is also suppressed within this range. Terms of peeling ultrathin copper layer without unevenness uniformly, and, from the viewpoint of suppressing a pinhole, molybdenum deposition amount is preferably set to 80~5000μg / dm ^2, be 100-1000 / dm ² More preferred. Nickel coating weight is preferably set to 100~20000μg / dm ^2, and more preferably a 1000~15000μg / dm ^2. Cobalt deposition amount is preferably set to 80~5000μg / dm ^2, and more preferably set to 100-1000 / dm ^2. Iron deposition amount is preferably set to 80~5000μg / dm ^2, and more preferably set to 100-1000 / dm ^2.

  Nickel or a nickel alloy may be provided between the carrier and the intermediate layer. The nickel provided at this position is expected to have a barrier effect that prevents the copper component from diffusing from the carrier into the ultrathin copper layer.

  The intermediate layer molybdenum-nickel alloy, or molybdenum-cobalt alloy, or molybdenum-iron alloy is formed by wet plating such as electroplating, electroless plating and immersion plating, or dry plating such as sputtering, CVD and PDV. can do. Electroplating is preferable from the viewpoint of cost.

<3. Strike plating>
An ultrathin copper layer is provided on the intermediate layer. Before that, strike plating with a copper-phosphorus alloy may be performed in order to reduce pinholes in the ultrathin copper layer. Examples of the strike plating include a copper pyrophosphate plating solution.

<4. Ultrathin copper layer>
An ultrathin copper layer is provided on the intermediate layer. The ultra-thin copper layer can be formed by electroplating using an electrolytic bath such as copper sulfate, copper pyrophosphate, copper sulfamate, copper cyanide, etc., and is used in general electrolytic copper foil with high current density. Since a copper foil can be formed, a copper sulfate bath is preferable. The thickness of the ultrathin copper layer is not particularly limited, but is generally thinner than the carrier, for example, 12 μm or less. It is typically 0.5-12 μm, more typically 2-5 μm.

<5. Roughening>
A roughening treatment layer may be provided on the surface of the ultrathin copper layer by performing a roughening treatment, for example, in order to improve adhesion to the insulating substrate. The roughening treatment can be performed, for example, by forming roughened particles with copper or a copper alloy. The roughening process may be fine. The roughening treatment layer is a layer made of any single element selected from the group consisting of copper, nickel, cobalt, phosphorus, tungsten, arsenic, molybdenum, chromium and zinc, or an alloy containing one or more of them. Also good. Moreover, after forming the roughened particles with copper or a copper alloy, a roughening treatment can be performed in which secondary particles or tertiary particles are further formed of nickel, cobalt, copper, zinc alone or an alloy. Thereafter, a heat-resistant layer or a rust-preventing layer may be formed of nickel, cobalt, copper, zinc alone or an alloy, and the surface thereof may be further subjected to a treatment such as a chromate treatment or a silane coupling treatment. Alternatively, a heat-resistant layer or a rust-preventing layer may be formed from nickel, cobalt, copper, zinc alone or an alloy without roughening, and the surface may be subjected to a treatment such as chromate treatment or silane coupling treatment. Good. That is, one or more layers selected from the group consisting of a heat resistant layer, a rust preventive layer, a chromate treated layer and a silane coupling treated layer may be formed on the surface of the roughened treated layer. One or more layers selected from the group consisting of a heat-resistant layer, a rust prevention layer, a chromate treatment layer, and a silane coupling treatment layer may be formed on the surface. In addition, the above-mentioned heat-resistant layer, rust prevention layer, chromate treatment layer, and silane coupling treatment layer may each be formed of a plurality of layers such as two or more layers or three layers or more.

As the heat-resistant layer and the rust-proof layer, known heat-resistant layers and rust-proof layers can be used. For example, the heat-resistant layer and / or the anticorrosive layer is a group of nickel, zinc, tin, cobalt, molybdenum, copper, tungsten, phosphorus, arsenic, chromium, vanadium, titanium, aluminum, gold, silver, platinum group elements, iron, tantalum A layer containing one or more elements selected from nickel, zinc, tin, cobalt, molybdenum, copper, tungsten, phosphorus, arsenic, chromium, vanadium, titanium, aluminum, gold, silver, platinum group elements Further, it may be a metal layer or an alloy layer made of one or more elements selected from the group consisting of iron, tantalum and the like. The heat-resistant layer and / or rust preventive layer is a group of nickel, zinc, tin, cobalt, molybdenum, copper, tungsten, phosphorus, arsenic, chromium, vanadium, titanium, aluminum, gold, silver, platinum group elements, iron, and tantalum. An oxide, nitride, or silicide containing one or more elements selected from the above may be included. Further, the heat-resistant layer and / or the rust preventive layer may be a layer containing a nickel-zinc alloy. Further, the heat-resistant layer and / or the rust preventive layer may be a nickel-zinc alloy layer. The nickel-zinc alloy layer may contain 50 wt% to 99 wt% nickel and 50 wt% to 1 wt% zinc, excluding inevitable impurities. The total adhesion amount of zinc and nickel in the nickel-zinc alloy layer may be 5 to 1000 mg / m ² , preferably 10 to 500 mg / m ² , preferably 20 to 100 mg / m ² . Further, the ratio of the nickel adhesion amount and the zinc adhesion amount of the layer containing the nickel-zinc alloy or the nickel-zinc alloy layer (= nickel adhesion amount / zinc adhesion amount) is 1.5 to 10. It is preferable. Further, the nickel - in adhesion amount of nickel in the zinc alloy layer is preferably from ^{0.5mg / m 2 ~500mg / m 2} , 1mg / m 2 ~50mg / m 2 - zinc alloy layer or the nickel containing More preferably. When the heat-resistant layer and / or rust prevention layer is a layer containing a nickel-zinc alloy, the interface between the copper foil and the resin substrate is eroded by the desmear liquid when the inner wall such as a through hole or via hole comes into contact with the desmear liquid. It is difficult to improve the adhesion between the copper foil and the resin substrate.

For example heat-resistant layer and / or anticorrosive layer has coating weight of 1 mg / m ² -100 mg / m ^2, preferably from 5 mg / m ² and to 50 mg / m ² of nickel or nickel alloy layer, the adhesion amount is 1 mg / m ² to 80 mg / m ^2, preferably it may be obtained by sequentially laminating a tin layer of ^{5mg / m 2 ~40mg / m 2} , wherein the nickel alloy layer of nickel - molybdenum, nickel - zinc, nickel - molybdenum - cobalt You may be comprised by any one of these. The heat-resistant layer and / or anticorrosive layer, it is ^{preferably, 10mg / m 2 ~70mg / m} 2 total deposition amount of nickel or nickel alloy and tin is 2mg / m ² ~150mg / m 2 It is more preferable. Further, the heat-resistant layer and / or the rust preventive layer is preferably [nickel or nickel adhesion amount in nickel or nickel alloy] / [tin adhesion amount] = 0.25 to 10, preferably 0.33 to 3. More preferred. When the heat-resistant layer and / or rust-preventing layer is used, the carrier-clad copper foil is processed into a printed wiring board, and the subsequent circuit peeling strength, the chemical resistance deterioration rate of the peeling strength, and the like are improved.

  In addition, you may use a well-known silane coupling agent for the silane coupling agent used for a silane coupling process, for example, using an amino-type silane coupling agent or an epoxy-type silane coupling agent, a mercapto-type silane coupling agent. Good. Silane coupling agents include vinyltrimethoxysilane, vinylphenyltrimethoxylane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, 4-glycidylbutyltrimethoxysilane, and γ-aminopropyl. Triethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-3- (4- (3-aminopropoxy) ptoxy) propyl-3-aminopropyltrimethoxysilane, imidazolesilane, triazinesilane, γ-mercaptopropyltrimethoxysilane or the like may be used.

  The silane coupling treatment layer may be formed using a silane coupling agent such as an epoxy silane, an amino silane, a methacryloxy silane, or a mercapto silane. In addition, you may use 2 or more types of such silane coupling agents in mixture. Especially, it is preferable to form using an amino-type silane coupling agent or an epoxy-type silane coupling agent.

  The amino silane coupling agent referred to here is N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, 3- (N-styrylmethyl-2-aminoethylamino) propyltrimethoxysilane, 3- Aminopropyltriethoxysilane, bis (2-hydroxyethyl) -3-aminopropyltriethoxysilane, aminopropyltrimethoxysilane, N-methylaminopropyltrimethoxysilane, N-phenylaminopropyltrimethoxysilane, N- (3 -Acryloxy-2-hydroxypropyl) -3-aminopropyltriethoxysilane, 4-aminobutyltriethoxysilane, (aminoethylaminomethyl) phenethyltrimethoxysilane, N- (2-aminoethyl-3-aminopropyl) Trimethoxysilane, N (2-Aminoethyl-3-aminopropyl) tris (2-ethylhexoxy) silane, 6- (aminohexylaminopropyl) trimethoxysilane, aminophenyltrimethoxysilane, 3- (1-aminopropoxy) -3,3- Dimethyl-1-propenyltrimethoxysilane, 3-aminopropyltris (methoxyethoxyethoxy) silane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, ω-aminoundecyltrimethoxysilane, 3- (2 -N-benzylaminoethylaminopropyl) trimethoxysilane, bis (2-hydroxyethyl) -3-aminopropyltriethoxysilane, (N, N-diethyl-3-aminopropyl) trimethoxysilane, (N, N- Dimethyl-3-aminopropyl) Limethoxysilane, N-methylaminopropyltrimethoxysilane, N-phenylaminopropyltrimethoxysilane, 3- (N-styrylmethyl-2-aminoethylamino) propyltrimethoxysilane, γ-aminopropyltriethoxysilane, N -Β (aminoethyl) γ-aminopropyltrimethoxysilane, N-3- (4- (3-aminopropoxy) ptoxy) propyl-3-aminopropyltrimethoxysilane Good.

The silane coupling treatment layer is 0.05 mg / m ^{2 to} 200 mg / m ² , preferably 0.15 mg / m ^{2 to} 20 mg / m ² , preferably 0.3 mg / m ^{2 to} 2.0 mg in terms of silicon atoms. / M ² is desirable. In the case of the above-mentioned range, the adhesiveness between the base resin and the surface-treated copper foil can be further improved.

<6. Copper foil with carrier>
The copper foil with a carrier of the present invention has a maximum molybdenum concentration of 1 when a 50 to 1000 nm long STEM line analysis is performed in a range including all of them in this order from the cross section of carrier / intermediate layer / ultra thin copper layer. -70 mass%. The maximum value of the molybdenum concentration is preferably 3 to 70% by mass, more preferably 3 to 55% by mass, more preferably 5 to 50% by mass, and even more preferably 10 to 45% by mass.

  Thus, the copper foil with a carrier of the present invention has a maximum molybdenum concentration when a 50 to 1000 nm long STEM line analysis is performed in a range including all of them in this order from the cross section of the carrier / intermediate layer / ultra thin copper layer. The value is controlled to 1 to 70% by mass. For this reason, peelability is good and generation | occurrence | production of the pinhole in the ultra-thin copper layer side surface is suppressed favorably. Also, in the copper foil with a carrier after thermocompression bonding, a certain amount of molybdenum is present on the outermost surface of the intermediate layer when the copper foil carrier is peeled from the ultrathin copper layer. For this reason, generation | occurrence | production of the pinhole in an ultra-thin copper layer side surface is suppressed favorably. Further, when the concentration of molybdenum is in the above preferable range, the number of blisters generated when heated may be reduced.

Moreover, the copper foil with a carrier of the present invention has a copper foil carrier / intermediate when an insulating substrate is thermocompression bonded to an ultrathin copper layer under the conditions of pressure: 20 kgf / cm ² and 220 ° C. × 2 hours. When a 50 to 1000 nm long STEM line analysis is performed in a range including all of them in this order from the cross section of the layer / ultra thin copper layer, the maximum value of the molybdenum concentration is preferably 1 to 60% by mass. The maximum value of the molybdenum concentration is more preferably 3 to 55% by mass, still more preferably 5 to 50% by mass, and still more preferably 10 to 45% by mass.

  When the copper foil with a carrier of the present invention is subjected to a 50 to 1000 nm long STEM line analysis in a range including all of them in this order from the cross section of the copper foil carrier / intermediate layer / ultra thin copper layer, the maximum value of the nickel concentration Is 50 to 95% by mass, and the molybdenum concentration is preferably 5 to 60% by mass at the maximum. According to such a configuration, nickel or a nickel alloy serves as an anti-diffusion layer between the ultrathin copper layer and the carrier, and the peel strength after pressing the insulating substrate is stabilized at a more appropriate value. The maximum value of the nickel concentration is more preferably 55 to 90% by mass, still more preferably 60 to 85% by mass, and even more preferably 65 to 80% by mass. The maximum value of the molybdenum concentration is more preferably 8 to 55% by mass, still more preferably 10 to 50% by mass, and even more preferably 15 to 45% by mass.

The copper foil with a carrier of the present invention has a copper foil carrier / intermediate layer / layer when an insulating substrate is thermocompression bonded to the ultrathin copper layer under the conditions of pressure: 20 kgf / cm ² and 220 ° C. × 2 hours. From the cross section of the ultra-thin copper layer, when 50 to 1000 nm long STEM line analysis is performed in a range including all of them in this order, in a portion where molybdenum, nickel and / or cobalt and / or iron, and copper coexist The minimum copper concentration is preferably 10 to 65% by mass. According to such a configuration, when an appropriate concentration of copper is present in the intermediate layer, the peel strength does not become extremely high or low, and can be peeled with an appropriate strength. The minimum copper concentration is more preferably 15 to 60% by mass, still more preferably 18 to 55% by mass, and even more preferably 20 to 50% by mass.

  When the current density in the plating treatment of molybdenum, cobalt, and iron is lowered and the carrier transport speed is lowered, the density of the layer containing molybdenum, cobalt, and iron is increased. When the density of the layer containing molybdenum, cobalt, and iron is increased, nickel in the layer containing copper and nickel as carriers becomes difficult to diffuse, and the concentration of molybdenum, cobalt, and iron can be controlled. The higher the nickel current density is set to increase the electrodeposition rate per unit time, and the higher the carrier transport speed, the lower the density of the layer containing nickel. When the density of the layer containing nickel decreases, the copper of the carrier copper foil easily diffuses into the nickel layer, and the concentration of copper in nickel can be controlled. The higher the current density in the plating process of molybdenum, cobalt, and iron, the higher the electrodeposition rate per unit time, and the faster the carrier transport speed, the lower the density of the layer containing molybdenum, cobalt, and iron. To do. When the density of the layer containing molybdenum, cobalt, and iron decreases, the copper of the carrier copper foil easily diffuses into the layer containing molybdenum, cobalt, and iron, and controls the concentration of copper in the layer containing molybdenum, cobalt, and iron. be able to. Further, by controlling the concentration of copper, the concentrations of molybdenum, cobalt, and iron can also be controlled. Further, the molybdenum concentration in the intermediate layer can be controlled by increasing the concentration of molybdenum in the plating solution of molybdenum, cobalt, and iron and increasing the current density.

The copper foil with a carrier of the present invention preferably has 0 / dm ² of bulges between the carrier and the ultrathin copper layer when heated in the atmosphere at 220 ° C. for 4 hours. Moreover, it is preferable that the number of blisters between the carrier and the ultrathin copper is 10 pieces / dm ² or less when heated in the atmosphere at 400 ° C. for 10 minutes. When the carrier-attached copper foil is heated, bubbles (bulges) may be generated by a gas such as water vapor generated between the carrier and the ultrathin copper layer. When such blisters occur, the ultrathin copper layer used for circuit formation sinks, causing a problem of adversely affecting circuit formability. On the other hand, if the occurrence of swelling after a predetermined heat treatment is suppressed as described above, such a problem is less likely to occur.

  The method of using the copper foil with carrier itself is well known to those skilled in the art. For example, the surface of the ultra-thin copper layer is made of paper base phenol resin, paper base epoxy resin, synthetic fiber cloth base epoxy resin, glass cloth / paper composite. Base epoxy resin, glass cloth / glass nonwoven fabric composite base epoxy resin and glass cloth base epoxy resin, polyester film, polyimide film, etc. The printed wiring board can be finally manufactured by etching the ultrathin copper layer adhered to the substrate into a desired conductor pattern. Furthermore, a printed circuit board is completed by mounting electronic components on the printed wiring board.

Moreover, the copper foil with a carrier provided with the copper foil carrier and the ultrathin copper layer laminated on the intermediate layer on the copper foil carrier is roughened on the ultrathin copper layer. A layer may be provided, and one or more layers selected from the group consisting of a heat-resistant layer, a rust preventive layer, a chromate treatment layer, and a silane coupling treatment layer may be provided on the roughening treatment layer.
Further, a roughening treatment layer may be provided on the ultrathin copper layer, a heat resistant layer and a rust prevention layer may be provided on the roughening treatment layer, and a chromate treatment is performed on the heat resistance layer and the rust prevention layer. A layer may be provided, and a silane coupling treatment layer may be provided on the chromate treatment layer.
The carrier-attached copper foil includes a resin layer on the ultrathin copper layer, the roughened layer, the heat-resistant layer, the rust-proof layer, the chromate-treated layer, or the silane coupling-treated layer. May be. The resin layer may be an insulating resin layer.

  The resin layer may be an adhesive, or an insulating resin layer in a semi-cured state (B stage state) for bonding. The semi-cured state (B stage state) is a state in which there is no sticky feeling even if the surface is touched with a finger, the insulating resin layer can be stacked and stored, and a curing reaction occurs when subjected to heat treatment. Including that.

  The resin layer may contain a thermosetting resin or may be a thermoplastic resin. The resin layer may include a thermoplastic resin. The type is not particularly limited. For example, epoxy resin, polyimide resin, polyfunctional cyanate ester compound, maleimide compound, maleimide resin, polyvinyl acetal resin, urethane resin, polyethersulfone, polyethersulfone Resin, aromatic polyamide resin, polyamideimide resin, rubber-modified epoxy resin, phenoxy resin, carboxyl group-modified acrylonitrile-butadiene resin, polyphenylene oxide, bismaleimide triazine resin, thermosetting polyphenylene oxide resin, cyanate ester resin, polyvalent carboxyl A resin containing an acid anhydride or the like can be mentioned as a preferable one. The resin layer may be a resin layer containing a block copolymerized polyimide resin layer or a resin layer containing a block copolymerized polyimide resin and a polymaleimide compound. The epoxy resin has two or more epoxy groups in the molecule and can be used without any problem as long as it can be used for electric / electronic materials. The epoxy resin is preferably an epoxy resin epoxidized using a compound having two or more glycidyl groups in the molecule. Bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AD type epoxy resin, novolac type epoxy resin, cresol novolac type epoxy resin, alicyclic epoxy resin, brominated epoxy resin, glycidylamine Type epoxy resin, triglycidyl isocyanurate, glycidylamine compound such as N, N-diglycidylaniline, glycidyl ester compound such as tetrahydrophthalic acid diglycidyl ester, phosphorus-containing epoxy resin, biphenyl type epoxy resin, biphenyl novolac type epoxy resin, One or two or more selected from the group of trishydroxyphenylmethane type epoxy resin and tetraphenylethane type epoxy resin can be used, or the above-mentioned Hydrogenated member or halogen embodying the carboxy resin can be used.

  The polyhydric carboxylic acid anhydride is preferably a component that contributes as a curing agent for the epoxy resin. The anhydride of the polyvalent carboxylic acid is phthalic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, tetrahydroxyphthalic anhydride, hexahydroxyphthalic anhydride, methylhexahydroxyphthalic anhydride, nadine. Acid and methyl nadic acid are preferred.

  The resin composition for forming the resin layer may contain an anhydride of polyvalent carboxylic acid, a phenoxy resin, and an epoxy resin. The acid anhydride is preferably contained in an amount of 0.01 mol to 0.5 mol with respect to 1 mol of a hydroxyl group contained in the phenoxy resin. As the phenoxy resin, one synthesized by a reaction between bisphenol and a divalent epoxy resin can be used. The content of the phenoxy resin may be 3 to 30 parts by weight when the total amount of the resin composition is 100 parts by weight. The epoxy resin may be an epoxy resin epoxidized with a compound having two or more glycidyl groups in the molecule. The resin composition can be obtained by reacting a polycarboxylic acid anhydride with a phenoxy resin, ring-opening addition of the polyvalent carboxylic acid to the hydroxyl group of the phenoxy resin, and then adding an epoxy resin. it can.

  As the bisphenol, bisphenol A, bisphenol F, bisphenol S, tetrabromobisphenol A, 4,4′-dihydroxybiphenyl, HCA (9,10-Dihydro-9-Oxa-10-Phosphophenanthrene-10-Oxide), hydroquinone, naphthoquinone, etc. Bisphenol obtained as an adduct with quinones can be used.

The thermoplastic resin may be a thermoplastic resin having a functional group other than an alcoholic hydroxyl group polymerizable with an epoxy resin.
The composition of the resin layer contains 50 to 90% by weight of an epoxy resin, 5 to 20% by weight of a polyvinyl acetal resin, and 0.1 to 20% by weight of a urethane resin with respect to the total amount of the resin components. 40% by weight may be a rubber-modified epoxy resin.
The polyvinyl acetal resin may have a functional group polymerizable with an epoxy resin or a maleimide compound other than an acid group and a hydroxyl group. Functionality polymerizable with 40-80 parts by weight of epoxy resin composition, 10-50 parts by weight of maleimide compound, epoxy resin other than hydroxyl group and hydroxyl group or maleimide compound with respect to 100 parts by weight of the total resin composition used in the resin layer It may be from 5 to 30 parts by weight of a polyvinyl acetal resin having a group. Further, the polyvinyl acetal resin may have a carboxyl group, an amino group or an unsaturated double bond introduced into the molecule.

  The resin layer is 20 to 80 parts by weight of an epoxy resin (including a curing agent), 20 to 80 parts by weight of an aromatic polyamide resin polymer soluble in a solvent, and a curing that is added in an appropriate amount as necessary. It may be formed using a resin composition made of an accelerator. In addition, the resin layer is 5 to 80 parts by weight of an epoxy resin (including a curing agent), 20 to 95 parts by weight of an aromatic polyamide resin polymer soluble in a solvent, and curing that is added in an appropriate amount as necessary. It may be formed using a resin composition made of an accelerator. The aromatic polyamide resin polymer used for the composition of the resin composition used for forming the resin layer may be obtained by reacting an aromatic polyamide with a rubber resin. The resin layer may contain a dielectric filler. The resin layer may contain a skeleton material.

  Here, examples of the aromatic polyamide resin polymer include those obtained by reacting an aromatic polyamide resin and a rubber resin. Here, the aromatic polyamide resin is synthesized by condensation polymerization of an aromatic diamine and a dicarboxylic acid. In this case, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylsulfone, m-xylenediamine, 3,3'-oxydianiline, or the like is used as the aromatic diamine. As the dicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, fumaric acid or the like is used.

  The rubbery resin to be reacted with the aromatic polyamide resin is described as a concept including natural rubber and synthetic rubber, and the latter synthetic rubber includes styrene-butadiene rubber, butadiene rubber, butyl rubber, ethylene-propylene. There is rubber. Furthermore, when ensuring the heat resistance of the dielectric layer to be formed, it is also useful to select and use a synthetic rubber having heat resistance such as nitrile rubber, chloroprene rubber, silicon rubber, urethane rubber or the like. Since these rubber resins react with an aromatic polyamide resin to produce a copolymer, it is desirable to have various functional groups at both ends. In particular, it is useful to use CTBN (carboxy group-terminated butadiene nitrile).

  The aromatic polyamide resin and rubber resin that constitute the aromatic polyamide resin polymer are preferably used in a blend of 25 wt% to 75 wt% of the aromatic polyamide resin and the remaining rubber resin. When the aromatic polyamide resin is less than 25 wt%, the abundance ratio of the rubber component is too high and the heat resistance is inferior. On the other hand, when it exceeds 75 wt%, the abundance ratio of the aromatic polyamide resin is too large to be cured. Later hardness becomes too high and becomes brittle. This aromatic polyamide resin polymer is used for the purpose of not being damaged by under-etching by an etchant when etching a copper foil after being processed into a copper-clad laminate.

  The aromatic polyamide resin polymer is required to have a property of being soluble in a solvent. This aromatic polyamide resin polymer is used in a blending ratio of 20 to 80 parts by weight. When the amount of the aromatic polyamide resin polymer is less than 20 parts by weight, it becomes too brittle under general press conditions for producing a copper clad laminate, and becomes microcracked easily on the substrate surface. On the other hand, there is no particular problem even if the aromatic polyamide resin polymer is added in an amount exceeding 80 parts by weight, but the strength after curing is not further improved even if the aromatic polyamide resin polymer is added in an amount exceeding 80 parts by weight. It is. Therefore, if economics are considered, it can be said that 80 weight part is an upper limit.

  “A curing accelerator to be added in an appropriate amount as needed” includes tertiary amines, imidazoles, urea-based curing accelerators, and the like. In the present invention, the mixing ratio of the curing accelerator is not particularly limited. This is because the curing accelerator may be arbitrarily selected by the manufacturer in consideration of production conditions in the process of producing the copper-clad laminate.

The resin composition for forming the resin layer is prepared by dissolving three types of epoxy resins, a bisphenol A type epoxy resin, a cresol novolac type epoxy resin, and a brominated bisphenol A type epoxy resin, in a solvent, and a curing agent and finely pulverizing them. It may be a resin composition to which a reaction catalyst such as silica or antimony trioxide is added. The curing agent at this time is the same as described above. This resin composition also shows good adhesion between the copper foil and the base resin.
The resin composition for forming the resin layer is polyphenylene ether resin, 2,2-bis (4-cyanatophenyl) propane, phosphorus-containing phenol compound, manganese naphthenate, 2,2-bis (4-glycidylphenyl) It may be a polyphenylene ether-cyanate resin composition in which propane is dissolved in a solvent. This resin composition also shows good adhesion between the copper foil and the base resin.
The resin composition for forming the resin layer may be a siloxane-modified polyamideimide resin composition or a siloxane-modified polyamideimide resin composition in which a cresol novolac type epoxy resin is dissolved in a solvent. This resin composition also shows good adhesion between the copper foil and the base resin.

(In the case of a resin layer containing a dielectric (dielectric filler))
When a dielectric (dielectric filler) is included in any of the above resin layers or resin compositions, it can be used for the purpose of forming a capacitor layer and increase the capacitance of the capacitor circuit. The dielectric (dielectric filler) includes a composite oxide having a perovskite structure such as BaTiO3, SrTiO3, Pb (Zr-Ti) O3 (common name PZT), PbLaTiO3 / PbLaZrO (common name PLZT), SrBi2Ta2O9 (common name SBT). Dielectric powder is used.

  The dielectric (dielectric filler) may be powdery. When the dielectric (dielectric filler) is powdery, the powder characteristics of the dielectric (dielectric filler) are as follows. First, the particle size is 0.01 μm to 3.0 μm, preferably 0.02 μm to 2.0 μm. Must be in range. The particle size referred to here is indirect in which the average particle size is estimated from the measured values of the laser diffraction scattering type particle size distribution measurement method and the BET method because the particles form a certain secondary aggregation state. It cannot be used because the accuracy is inferior in measurement, and it refers to the average particle diameter obtained by directly observing a dielectric (dielectric filler) with a scanning electron microscope (SEM) and image analysis of the SEM image. It is. In this specification, the particle size at this time is indicated as DIA. The image analysis of the dielectric (dielectric filler) powder observed using a scanning electron microscope (SEM) in this specification is performed using IP-1000PC manufactured by Asahi Engineering Co., Ltd. Circular particle analysis was performed with a threshold value of 10 and an overlapping degree of 20, and the average particle diameter DIA was obtained.

  Furthermore, the volume cumulative particle diameter D50 by the laser diffraction scattering particle size distribution measurement method is 0.2 μm to 2.0 μm, and the volume cumulative particle diameter D50 and the average particle diameter DIA obtained by image analysis are used to obtain D50 / It is required to be a dielectric powder having a substantially spherical perovskite structure with a cohesion value represented by DIA of 4.5 or less.

  The volume cumulative particle size D50 by the laser diffraction scattering type particle size distribution measurement method is a particle size at 50% weight cumulative obtained by using the laser diffraction scattering type particle size distribution measurement method, and the value of this volume cumulative particle size D50. The smaller the is, the larger the proportion of fine powder particles in the particle size distribution of the dielectric (dielectric filler) powder. In the present invention, this value is required to be 0.2 μm to 2.0 μm. That is, when the value of the volume cumulative particle diameter D50 is less than 0.2 μm, the progress of aggregation is remarkably satisfied with the degree of aggregation described below regardless of the production method of dielectric (dielectric filler) powder. It is not what you do. On the other hand, when the value of the volume cumulative particle diameter D50 exceeds 2.0 μm, it cannot be used as a dielectric (dielectric filler) for forming a built-in capacitor layer of a printed wiring board, which is an object of the present invention. It becomes. That is, the dielectric layer of the double-sided copper-clad laminate used to form the built-in capacitor layer is usually 10 μm to 25 μm thick, and 2.0 μm to uniformly disperse the dielectric filler therein. Is the upper limit.

  In the present invention, the volume cumulative particle size D50 is measured by mixing and dispersing dielectric (dielectric filler) powder in methyl ethyl ketone, and using this solution as a laser diffraction scattering type particle size distribution measuring device, Micro Trac HRA 9320-X100 (manufactured by Nikkiso Co., Ltd.). ) And then measured.

  Here, the concept of cohesion is used, which is adopted for the following reason. That is, the value of the volume cumulative particle size D50 obtained by using the laser diffraction / scattering particle size distribution measurement method is considered not to be a direct observation of each individual particle size. This is because the powder particles constituting most of the dielectric powder are not so-called monodispersed powders in which individual particles are completely separated, but are in a state where a plurality of powder particles are aggregated and aggregated. This is because the laser diffraction / scattering particle size distribution measurement method regards the aggregated particles as one particle (aggregated particle) and calculates the volume cumulative particle size.

  On the other hand, since the average particle diameter DIA obtained by image processing the observation image of the dielectric powder observed using the scanning electron microscope is obtained directly from the SEM observation image, the primary particles are surely obtained. On the other hand, the presence of the agglomerated state of the particles is not reflected at all.

  Considering the above, the present inventors calculated the value calculated by D50 / DIA using the volume cumulative particle diameter D50 of the laser diffraction scattering particle size distribution measurement method and the average particle diameter DIA obtained by image analysis. Is regarded as the degree of cohesion. That is, assuming that the values of D50 and DIA can be measured with the same accuracy in the same lot of copper powder, considering the above-mentioned theory, the value of D50 that reflects the presence of an agglomerated state is DIA. It is considered that the value is larger than the value of.

  At this time, the value of D50 approaches the value of DIA as much as possible if the state of aggregation of the dielectric (dielectric filler) powder is completely eliminated. The value of D50 / DIA as the degree of aggregation is It approaches 1 It can be said that it is a monodispersed powder in which the agglomeration state of the powder is completely lost when the aggregation degree becomes 1. However, in reality, the degree of aggregation may be less than 1. Theoretically, in the case of a true sphere, it does not become a value less than 1, but in reality, it seems that a cohesion value of less than 1 is obtained because the powder is not a true sphere. is there.

  In this invention, it is preferable that the aggregation degree of this dielectric material (dielectric filler) powder is 4.5 or less. If this degree of aggregation exceeds 4.5, the level of aggregation between the powder particles of the dielectric filler becomes too high, and uniform mixing with the above-described resin composition becomes difficult.

  As a method for producing a dielectric (dielectric filler) powder, a fixed aggregation state is inevitably formed even if any production method such as an alkoxide method, a hydrothermal synthesis method, or an oxalate method is employed. Dielectric filler powder that does not satisfy the degree of aggregation can be generated. In particular, in the case of the hydrothermal synthesis method which is a wet method, the formation of an aggregated state tends to occur. Therefore, the aggregated state of the dielectric filler powder can be set within the above-described aggregation degree range by performing a pulverization process for separating the agglomerated powder into one granular particle. is there.

  If the purpose is simply pulverization, high energy ball mill, high-speed conductor impingement airflow pulverizer, impact pulverizer, gauge mill, medium agitation mill, high water pressure Various things such as a pulverizer can be used. However, in order to ensure the mixing and dispersibility of the dielectric (dielectric filler) powder and the resin composition, it should be considered to reduce the viscosity as a dielectric (dielectric filler) -containing resin solution described below. . In order to reduce the viscosity of the dielectric (dielectric filler) -containing resin solution, the specific surface area of the dielectric particles (dielectric filler) is required to be small and smooth. Therefore, even if granulation is possible, it should not be a granulation technique that damages the surface of the granule during granulation and increases its specific surface area.

  Based on this recognition, the inventors of the present invention diligently researched and found that the two methods are effective. What is common to these two methods is that the powder particles of the dielectric (dielectric filler) are agglomerated while minimizing the contact of the powder with the inner wall of the device, the stirring blade, the grinding media, etc. This is a method capable of sufficiently pulverizing particles by causing the particles to collide with each other. That is, contact with parts such as the inner wall of the apparatus, stirring blades, and grinding media damages the surface of the powder, increases the surface roughness, and deteriorates the sphericity, thereby preventing this. . Then, by causing sufficient collision between the powder particles, it is possible to disaggregate the powder particles in an agglomerated state, and at the same time, it is possible to employ a method capable of smoothing the surface of the powder particles by the collision between the powder particles.

  One of them is a pulverization treatment of dielectric (dielectric filler) powder in an agglomerated state using a jet mill. “Jet mill” as used here refers to the use of a high-speed air current to place dielectric (dielectric filler) powder in this air current, and the particles collide with each other in this high-speed air current to break up the particles. Is done.

  In addition, a slurry in which a dielectric (dielectric filler) powder in an agglomerated state is dispersed in a solvent that does not destroy the stoichiometry is pulverized using a fluid mill using centrifugal force. By using the “fluid mill using centrifugal force”, the slurry is allowed to flow at a high speed so as to draw a circumferential trajectory. And then pulverize. By doing in this way, the dielectric (dielectric filler) powder which finished the granulation work is obtained by washing, filtering, and drying the slurry after the granulation work. By the method described above, the degree of aggregation can be adjusted and the powder surface of the dielectric filler powder can be smoothed.

  The resin composition described above and a dielectric (dielectric filler) are mixed to form a dielectric (dielectric filler) -containing resin for forming a built-in capacitor layer of a printed wiring board. In addition, resin which can be used for the said resin layer can be mentioned as resin used for the resin composition for mixing with a dielectric material (dielectric filler). At this time, the blending ratio of the resin composition and the dielectric (dielectric filler) is preferably such that the content of the dielectric (dielectric filler) is 75 wt% to 85 wt%, and the remaining resin composition.

When the content of the dielectric (dielectric filler) is less than 75 wt%, the relative permittivity of 20 currently required in the market cannot be satisfied, and the content of the dielectric (dielectric filler) exceeds 85 wt%. And the resin composition content is less than 15 wt%, the adhesiveness between the dielectric (dielectric filler) -containing resin and the copper foil laminated thereon is impaired, and the required characteristics for manufacturing a printed wiring board are satisfied. This makes it difficult to produce a copper-clad laminate.
The resin layer containing the dielectric (dielectric filler) may be formed using a resin composition containing a dielectric (dielectric filler), an epoxy resin, an active ester resin, a polyvinyl acetal resin, and a curing accelerator. Good.
Further, the resin layer containing the dielectric (dielectric filler) is 25 parts by weight of epoxy resin when the weight of the resin composition containing epoxy resin, active ester resin, polyvinyl acetal resin, and curing accelerator is 100 parts by weight. It may be formed using a resin composition containing ˜60 parts by weight and a dielectric (dielectric filler).
The resin layer containing the dielectric material (dielectric filler) is 28 weight parts of the active ester resin when the weight of the resin composition containing the epoxy resin, the active ester resin, the polyvinyl acetal resin, and the curing accelerator is 100 parts by weight. It may be formed using a resin composition containing a part to 60 parts by weight and a dielectric (dielectric filler).
Further, the resin layer containing the dielectric (dielectric filler) has an epoxy resin and an active ester resin when the weight of the resin composition containing an epoxy resin, an active ester resin, a polyvinyl acetal resin, and a curing accelerator is 100 parts by weight. May be formed using a resin composition containing 78 parts by weight to 95 parts by weight and a dielectric (dielectric filler).
In addition, the resin layer containing the dielectric (dielectric filler) has 1 weight of polyvinyl acetal resin when the weight of the resin composition containing epoxy resin, active ester resin, polyvinyl acetal resin, and curing accelerator is 100 parts by weight. It may be formed using a resin composition containing 20 parts by weight to 20 parts by weight and a dielectric (dielectric filler).
Further, the resin layer containing the dielectric (dielectric filler) has a curing accelerator of 0.00 when the weight of the resin composition containing epoxy resin, active ester resin, polyvinyl acetal resin, and curing accelerator is 100 parts by weight. It may be formed using a resin composition containing 01 to 2 parts by weight and a dielectric (dielectric filler).
Moreover, the resin layer containing the dielectric (dielectric filler) has an epoxy resin, an active ester resin, and a polyvinyl acetal constituting the resin composition when the weight of the resin composition constituting the resin layer is 100 parts by weight. It may be formed using a resin composition in which the total amount of each component of the resin and the curing accelerator is 70 parts by weight or more and a dielectric (dielectric filler).
The resin layer containing the dielectric contains a dielectric (dielectric filler) in a range of 65 wt% to 85 wt% when the weight of the resin containing the dielectric (dielectric filler) is 100 wt%. It is preferable that
The epoxy resin, active ester resin, polyvinyl acetal resin and curing accelerator include known epoxy resins, active ester resins, polyvinyl acetal resins and curing accelerators, or the epoxy resins, active ester resins and polyvinyl acetals described in the present specification. Resins and cure accelerators can be used.
The resin layer containing the dielectric (dielectric filler) preferably has a resin flow of less than 1% when measured according to MIL-P-13949G in the MIL standard.
In addition, as a hardening accelerator and an epoxy resin, a well-known thing or the hardening accelerator and epoxy resin as described in this-application specification can be used. Moreover, as a hardening accelerator, a well-known imidazole compound or the imidazole compound as described in this-application specification can be used.

  As this dielectric (dielectric filler), it is preferable to use barium titanate among complex oxides having a perovskite structure in consideration of manufacturing accuracy as a powder at the present stage. As the dielectric (dielectric filler) at this time, either calcined barium titanate or uncalcined barium titanate can be used. In order to obtain a high dielectric constant, it is preferable to use calcined barium titanate, but it may be selectively used according to the design quality of the printed wiring board product.

Furthermore, it is most preferable that the dielectric filler of barium titanate has a cubic crystal structure. The crystal structure of barium titanate includes cubic and tetragonal crystals, but the cubic barium titanate dielectric (dielectric filler) has a tetragonal structure only. The value of the dielectric constant of the finally obtained dielectric layer is stabilized as compared with the case where a barium acid dielectric (dielectric filler) is used. Therefore, it can be said that it is necessary to use barium titanate powder having both a cubic crystal structure and a tetragonal crystal structure.
According to the above-described embodiment, the resin layer containing the dielectric for forming the capacitor circuit layer having a low dielectric loss tangent is improved by improving the adhesion between the inner layer circuit surface of the inner layer core material and the resin layer containing the dielectric. The copper foil with a carrier which has can be provided.

  The resin layer is a cured resin layer (the “cured resin layer” means a cured resin layer) and a half in order from the copper foil side (that is, the ultrathin copper layer side of the copper foil with carrier). The resin layer which formed the cured resin layer sequentially may be sufficient. The cured resin layer may be composed of a resin component of any one of a polyimide resin, a polyamideimide resin, and a composite resin having a thermal expansion coefficient of 0 ppm / ° C. to 25 ppm / ° C.

  Moreover, you may provide the semi-hardened resin layer whose thermal expansion coefficient after hardening is 0 ppm / degrees C-50 ppm / degrees C on the said cured resin layer. In addition, the thermal expansion coefficient of the entire resin layer after the cured resin layer and the semi-cured resin layer are cured may be 40 ppm / ° C. or less. The cured resin layer may have a glass transition temperature of 300 ° C. or higher. The semi-cured resin layer may be formed using a maleimide resin, and the maleimide resin may be an aromatic maleimide resin having two or more maleimide groups in the molecule. The maleimide resin may be a polymerized adduct obtained by polymerizing an aromatic maleimide resin having two or more maleimide groups in the molecule and an aromatic polyamine. The semi-cured resin layer may contain 20 to 70 parts by weight of a maleimide resin when the semi-cured resin layer is 100 parts by weight. The resin composition for forming the semi-cured resin layer preferably contains a maleimide resin, an epoxy resin, and a linear polymer having a crosslinkable functional group as an essential component. The maleimide resin may be a polymerization adduct obtained by polymerizing an aromatic maleimide resin and an aromatic polyamine. Moreover, you may add the cyanoester resin and epoxy resin which have reactivity with a maleimide-type resin as needed to a semi-hardened resin layer. As the epoxy resin, a known epoxy resin or an epoxy resin described in the present specification can be used.

  Moreover, it is preferable that the linear polymer which has the said crosslinkable functional group is equipped with the functional group which contributes to hardening reaction of epoxy resins, such as a hydroxyl group and a carboxyl group. And it is preferable that the linear polymer which has this crosslinkable functional group is soluble in the organic solvent of the temperature of 50 to 200 degreeC of boiling points. Specific examples of the linear polymer having a functional group mentioned here include polyvinyl acetal resin, phenoxy resin, polyethersulfone resin, polyamideimide resin, and the like. The linear polymer having a crosslinkable functional group is preferably used in a blending ratio of 3 to 30 parts by weight when the resin composition is 100 parts by weight. When the epoxy resin is less than 3 parts by weight, the resin flow may increase. As a result, a large amount of resin powder may be observed from the end of the produced copper-clad laminate, and the moisture absorption resistance of the resin layer in a semi-cured state may not be improved. On the other hand, even if it exceeds 30 parts by weight, the resin flow may be small, and defects such as voids may easily occur in the insulating layer of the produced copper-clad laminate.

  As the maleimide resin here, 4,4′-diphenylmethane bismaleimide, polyphenylmethane maleimide, m-phenylene bismaleimide, bisphenol A diphenyl ether bismaleimide, 3,3′-dimethyl-5,5′-diethyl-4 , 4′-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, 4,4′-diphenyl ether bismaleimide, 4,4′-diphenylsulfone bismaleimide, 1,3-bis (3-maleimidophenoxy) Benzene, 1,3-bis (4-maleimidophenoxy) benzene and the like can be used. When the content of the maleimide resin is less than 20 parts by weight, the effect of reducing the thermal expansion coefficient of the semi-cured resin layer after curing may not be obtained. On the other hand, if the content of the maleimide resin exceeds 70 parts by weight, the semi-cured resin layer may become a brittle resin layer when cured, and the resin layer may be easily cracked. The reliability as a layer may be reduced.

  When forming a polymerization adduct obtained by polymerizing an aromatic maleimide resin having two or more maleimide groups in the molecule and an aromatic polyamine, examples of the aromatic polyamine include m-phenylenediamine and p-phenylenediamine. 4,4′-diaminodicyclohexylmethane, 1,4-diaminocyclohexane, 2,6-diaminopyridine, 4,4′-diaminodiphenylmethane, 2,2-bis (4-aminophenyl) propane, 4,4′- Diaminodiphenyl ether, 4,4′-diamino-3-methyldiphenyl ether, 4,4′-diaminodiphenyl sulfide, 4,4′-diaminobenzophenone, 4,4′-diaminodiphenyl sulfone, bis (4-aminophenyl) phenylamine , M-xylenediamine, p-xylenediamine 1,3-bis [4-aminophenoxy] benzene, 3-methyl-4,4′-diaminodiphenylmethane, 3,3′-diethyl-4,4′-diaminodiphenylmethane, 3,3′-dichloro-4,4 '-Diaminodiphenylmethane, 2,2', 5,5'-tetrachloro-4,4'-diaminodiphenylmethane, 2,2-bis (3-methyl-4-aminophenyl) propane, 2,2-bis (3 -Ethyl-4-aminophenyl) propane, 2,2-bis (2,3-dichloro-4-aminophenyl) propane, bis (2,3-dimethyl-4-aminophenyl) phenylethane, ethylenediamine and hexamethylenediamine Etc. are preferably added to the resin composition to form a resin layer.

  When an epoxy resin curing agent is required, amines such as dicyandiamide, imidazoles and aromatic amines, phenols such as bisphenol A and brominated bisphenol A, novolacs such as phenol novolac resin and cresol novolac resin Acid anhydrides such as phthalic anhydride are used. Since the addition amount of the epoxy resin curing agent with respect to the epoxy resin at this time is naturally derived from the respective equivalents, no special addition amount limitation is performed.

Moreover, when providing the copper foil with a carrier which has a resin layer suitable for a three-dimensional molded printed wiring board manufacture use, it is preferable that the said cured resin layer is a polymeric polymer layer which has hardened | cured flexibility. The polymer layer is preferably made of a resin having a glass transition temperature of 150 ° C. or higher so that it can withstand the solder mounting process. The polymer polymer layer is preferably made of one or a mixture of two or more of a polyamide resin, a polyether sulfone resin, an aramid resin, a phenoxy resin, a polyimide resin, a polyvinyl acetal resin, and a polyamideimide resin. The thickness of the polymer layer is preferably 3 μm to 10 μm.
Moreover, it is preferable that the said high polymer layer contains any 1 type, or 2 or more types of an epoxy resin, a maleimide resin, a phenol resin, and a urethane resin. The semi-cured resin layer is preferably composed of an epoxy resin composition having a thickness of 10 μm to 50 μm.

Moreover, it is preferable that the said epoxy resin composition contains each component of the following A component-E component.
Component A: An epoxy resin comprising one or more selected from the group consisting of a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, and a bisphenol AD type epoxy resin that have an epoxy equivalent of 200 or less and are liquid at room temperature.
B component: High heat resistant epoxy resin.
Component C: Phosphorus-containing flame-retardant resin, which is any one of phosphorus-containing epoxy resin and phosphazene-based resin, or a resin obtained by mixing these.
Component D: A rubber-modified polyamide-imide resin modified with a liquid rubber component having a property that is soluble in a solvent having a boiling point in the range of 50 ° C. to 200 ° C.
E component: Resin curing agent.

  The component A is an epoxy resin composed of one or more selected from the group consisting of a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, and a bisphenol AD type epoxy resin that have an epoxy equivalent of 200 or less and are liquid at room temperature. Here, the bisphenol-based epoxy resin is selectively used because it has good compatibility with the D component (rubber-modified polyamideimide resin) described later, and it is easy to impart appropriate flexibility to the resin film in a semi-cured state. It is. If the epoxy equivalent exceeds 200, the resin becomes semi-solid at room temperature, and the flexibility in the semi-cured state decreases, which is not preferable. Furthermore, if it is the above-mentioned bisphenol-type epoxy resin, 1 type may be used independently or 2 or more types may be used in mixture. In addition, when two or more kinds are mixed and used, there is no particular limitation with respect to the mixing ratio.

  This epoxy resin is preferably used in a blending ratio of 3 to 30 parts by weight, with 100 parts by weight of the epoxy resin composition constituting the semi-cured resin layer. When the epoxy resin is less than 3 parts by weight, the thermosetting property is not sufficiently exhibited, and the function as a binder with the inner layer flexible printed wiring board and the adhesiveness with the copper foil as the resin-coated copper foil are sufficient. Can't be done. On the other hand, when the amount exceeds 30 parts by weight, the viscosity of the resin varnish increases from the balance with other resin components, and when the resin-coated copper foil is produced, the resin film with a uniform thickness is formed on the copper foil surface. Formation becomes difficult. Moreover, considering the amount of D component (rubber-modified polyamideimide resin) to be described later, sufficient toughness as a cured resin layer cannot be obtained.

  The B component is a “high heat resistant epoxy resin” having a high so-called glass transition point Tg. The “high heat-resistant epoxy resin” referred to here is preferably a polyfunctional epoxy resin such as a novolac-type epoxy resin, a cresol novolac-type epoxy resin, a phenol novolac-type epoxy resin, or a naphthalene-type epoxy resin. And it is preferable to use this B component in the range of 3-30 weight part, when the epoxy resin composition which comprises a semi-hardened resin layer is 100 weight part. When the component B is less than 3 parts by weight, it is not preferable because the Tg of the resin composition tends to be insufficient. On the other hand, if the component B exceeds 30 parts by weight, the cured resin becomes brittle and flexibility is impaired, which is not preferable for flexible printed wiring board applications. More preferably, by using the B component in the range of 10 to 20 parts by weight, it is possible to stably achieve both high Tg of the resin composition and good flexibility of the cured resin.

  The component C is a so-called halogen-free flame-retardant resin, and a phosphorus-containing flame-retardant resin that is any one of a phosphorus-containing epoxy resin and a phosphazene-based resin or a mixture of these is used. First, the phosphorus-containing epoxy resin is a general term for epoxy resins containing phosphorus in an epoxy skeleton. And when the phosphorus atom content of the epoxy resin composition constituting the semi-cured resin layer is 100% by weight of the epoxy resin composition, the phosphorus atom derived from component C is 0.5% by weight to 3.0%. Any phosphorus-containing epoxy resin that can be in the range of% by weight can be used. However, among the phosphorus-containing epoxy resins described above, a phosphorus-containing epoxy resin which is a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative having two or more epoxy groups in the molecule is used. When used, it is preferable because it is excellent in the stability of the resin quality in the semi-cured state and at the same time has a high flame retardant effect. For reference, the structural formula of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is shown below.

  Furthermore, as a specific example of a phosphorus-containing epoxy resin that is a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative, a compound having the structural formula shown in Chemical Formula 2 is shown. The use of a compound having the structural formula shown in Chemical Formula 2 is preferable because the resin quality is more stable in a semi-cured state, and at the same time, the flame retardant effect is enhanced.

  Further, as the phosphorus-containing epoxy resin of component C, a compound having the structural formula shown in Chemical Formula 3 shown below is also preferable. Like the phosphorus-containing epoxy resin shown in Chemical Formula 2, the resin quality is excellent in the semi-cured state, and high flame retardancy can be imparted at the same time.

  Further, as the C-component phosphorus-containing epoxy resin, a compound having the structural formula shown in Chemical Formula 4 shown below is also preferable. Like the phosphorus-containing epoxy resin shown in Chemical Formula 2 and Chemical Formula 3, it is preferable because it is excellent in the stability of the resin quality in a semi-cured state and at the same time imparting high flame resistance.

  The epoxy resin obtained as a derivative from 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is converted to 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide. After making naphthoquinone or hydroquinone react to form a compound shown in the following chemical formula 5 (HCA-NQ) or chemical formula 6 (HCA-HQ), an epoxy resin is reacted with the OH group portion to make a phosphorus-containing flame retardant resin. Are listed.

  Here, the resin composition in the case of using a phosphorus-containing epoxy resin as the phosphorus-containing flame retardant resin is not limited to two or more types of phosphorus-containing epoxy resins, even if one kind of phosphorus-containing epoxy resin is used alone. You may mix and use. However, in consideration of the total amount of the phosphorus-containing flame retardant resin as the C component, when the weight of the epoxy resin composition constituting the semi-cured resin layer is 100% by weight, the phosphorus atom derived from the C component is 0.5% by weight. It is preferable to determine the addition amount so as to be in the range of% to 3.0% by weight. The phosphorus-containing epoxy resin has different amounts of phosphorus atoms contained in the epoxy skeleton depending on the type. Therefore, as described above, the phosphorus atom content can be designed with priority over the added amount of the C component.

  Next, a case where a phosphazene resin is used as the phosphorus-containing flame retardant resin will be described. The phosphazene resin is a resin containing phosphazene having a double bond having phosphorus and nitrogen as constituent elements. The phosphazene resin can dramatically improve the flame retardancy due to the synergistic effect of nitrogen and phosphorus in the molecule. In addition, unlike 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivatives, it exists stably in the resin, and the effect of preventing the occurrence of migration is obtained.

  Moreover, the resin composition in the case of using a phosphazene resin as the phosphorus-containing flame retardant resin may be used alone or in combination of two or more phosphazene resins. Absent. However, in consideration of the total amount of the phosphorus-containing flame retardant resin as the C component, when the weight of the phosphazene resin composition constituting the semi-cured resin layer is 100% by weight, the phosphorus atom derived from the C component is 0.5%. It is preferable to determine the addition amount so as to be in the range of wt% to 3.0 wt%. The same applies to the case where a phosphorus-containing epoxy resin and a phosphazene resin are mixed and used as the C component.

  As the phosphorus-containing flame retardant resin as the C component, any one of a phosphorus-containing epoxy resin and a phosphazene resin or a mixture thereof may be used. When the phosphorus-containing epoxy resin is used alone as the phosphorus-containing flame retardant resin, the phosphorus-containing epoxy resin is 5 parts by weight to 50 parts when the epoxy resin composition constituting the semi-cured resin layer is 100 parts by weight. It is preferably used in the range of parts by weight. When the C component comprising the phosphorus-containing epoxy resin is less than 5 parts by weight, considering the blending ratio of other resin components, phosphorus atoms derived from the C component are insufficient, and it becomes difficult to obtain flame retardancy. . On the other hand, even if the C component made of phosphorus-containing epoxy resin exceeds 50 parts by weight, the effect of improving flame retardancy is saturated, and at the same time, the cured resin layer becomes brittle.

  When a phosphazene resin is used alone as the phosphorus-containing flame retardant resin, the phosphazene resin is 2 to 18 parts by weight with respect to 100 parts by weight of the epoxy resin composition constituting the semi-cured resin layer. It is preferably used in the range of parts. When the C component composed of the phosphazene resin is less than 2 parts by weight, the phosphorus atom derived from the C component is insufficient and it becomes difficult to obtain flame retardancy in consideration of the blending ratio of the other resin components. On the other hand, when the C component made of phosphazene resin exceeds 18 parts by weight, the glass transition point Tg, solder heat resistance, and peel strength of the resin composition tend to be insufficient, which is not preferable.

  “High Tg” and “flexibility” of the cured resin described above are generally inversely proportional characteristics. At this time, there are phosphorus-containing flame retardant resins that contribute to the improvement of the flexibility of the cured resin and those that contribute to an increase in Tg. Therefore, rather than using one type of phosphorus-containing flame-retardant epoxy resin, “phosphorus-containing flame-retardant epoxy resin that contributes to higher Tg” and “phosphorus-containing flame-retardant epoxy resin that contributes to improved flexibility” By mixing and using in a well-balanced manner, it is possible to obtain a resin composition suitable for flexible printed wiring board applications.

  Component D is a rubber-modified polyamideimide resin that is soluble in a solvent having a boiling point in the range of 50 ° C. to 200 ° C. and modified with a liquid rubber component. This rubber-modified polyamideimide resin is obtained by reacting a polyamideimide resin and a rubber resin. The rubber-modified polyamide-imide resin and the rubber-like resin used here are reacted for the purpose of improving the flexibility of the polyamide-imide resin itself. That is, the polyamideimide resin and the rubber resin are reacted to replace a part of the acid component (cyclohexanedicarboxylic acid or the like) of the polyamideimide resin with the rubber component. The rubber component includes natural rubber and synthetic rubber. Examples of the latter synthetic rubber include styrene-butadiene rubber, butadiene rubber, butyl rubber, and ethylene-propylene rubber. Furthermore, from the viewpoint of ensuring heat resistance, it is also useful to selectively use a synthetic rubber having heat resistance such as nitrile rubber, chloroprene rubber, silicon rubber, urethane rubber and the like. Since these rubber resins react with the polyamide-imide resin to produce a copolymer, it is desirable to have various functional groups at both ends. In particular, it is useful to use CTBN (carboxy group-terminated butadiene nitrile) having a carboxyl group. In addition, the said rubber component may copolymerize only 1 type or may copolymerize 2 or more types. Further, when a rubber component is used, it is preferable to use a rubber component having a number average molecular weight of 1000 or more from the viewpoint of stabilization of the flexibility.

  Solvents used for dissolving the polyamideimide resin and the rubbery resin when polymerizing the rubber-modified polyamideimide resin include dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, dimethylsulfoxide, nitromethane, nitroethane, tetrahydrofuran , Cyclohexanone, methyl ethyl ketone, acetonitrile, γ-butyrolactone, and the like are preferably used alone or in combination. And in order to raise | generate a polymerization reaction, it is preferable to employ | adopt the polymerization temperature of the range of 80 to 200 degreeC. When a solvent having a boiling point of more than 200 ° C. is used for these polymerizations, it is preferable that the solvent be replaced with a solvent having a boiling point in the range of 50 ° C. to 200 ° C., depending on the application.

  Here, examples of the solvent having a boiling point in the range of 50 ° C. to 200 ° C. include one single solvent or two or more mixed solvents selected from the group of methyl ethyl ketone, dimethylacetamide, dimethylformamide and the like. When the boiling point is lower than 50 ° C., the solvent is greatly diffused by heating, and it is difficult to obtain a good semi-cured state when the resin varnish is changed to a semi-cured resin. On the other hand, when the boiling point exceeds 200 ° C., bubbling is likely to occur when the resin varnish is used as a semi-cured resin, so that it is difficult to obtain a good semi-cured resin film.

  Among the rubber-modified polyamideimide resins used in the epoxy resin composition, when the weight of the rubber-modified polyamideimide resin is 100% by weight, the copolymerization amount of the rubber component is preferably 0.8% by weight or more. When the copolymerization amount is less than 0.8% by weight, the rubber-modified polyamideimide resin lacks flexibility when the resin layer formed using the epoxy resin composition according to the present invention is cured. In addition, the adhesiveness with the copper foil is also lowered, which is not preferable. More preferably, the copolymerization amount of the rubber component is 3% by weight or more, more preferably 5% by weight or more. Empirically, there is no particular problem even if the amount of the rubber component added is increased beyond 40% by weight. However, since the effect of improving the flexibility of the cured resin layer is saturated, resources are wasted, which is not preferable.

  The rubber-modified polyamideimide resin described above is required to be soluble in a solvent. This is because preparation as a resin varnish is difficult unless it is soluble in a solvent. This rubber-modified polyamideimide resin is preferably used in a blending ratio of 10 to 40 parts by weight, when the weight of the resin composition is 100 parts by weight. When the rubber-modified polyamideimide resin is less than 10 parts by weight, the flexibility of the cured resin layer cannot be improved and becomes brittle, and microcracks are easily generated in the resin layer. On the other hand, adding rubber-modified polyamideimide resin in excess of 40 parts by weight has no particular problem, but the flexibility of the cured resin layer is not improved further, and the cured resin can have a higher Tg. Absent. Therefore, considering the economy, it can be said that 40 parts by weight is the upper limit.

  The E component resin curing agent will be described. As the resin curing agent referred to here, it is preferable to use one or more of biphenyl type phenol resin and phenol aralkyl type phenol resin. The addition amount of the resin curing agent is naturally derived from the reaction equivalent to the resin to be cured, and does not require any particular quantitative limitation. However, in the case of the epoxy resin composition used in the present invention, the E component is preferably used in the range of 20 to 35 parts by weight when the epoxy resin composition is 100 parts by weight. When the E component is less than 20 parts by weight, considering the resin composition, a sufficient cured state cannot be obtained, and flexibility as a cured resin cannot be obtained. On the other hand, when the E component exceeds 35 parts by weight, the moisture absorption resistance of the cured resin layer tends to deteriorate, which is not preferable.

A solvent is added to the resin composition shown above and used as a resin varnish, and a thermosetting resin layer is formed as an adhesive layer of a printed wiring board. The resin varnish is prepared by adding a solvent to the above resin composition so that the resin solid content is in the range of 30 wt% to 70 wt%, and the resin flow when measured in accordance with MIL-P-13949G in the MIL standard. A semi-cured resin film in the range of 5% to 35% can be formed. As the solvent, the boiling point is in the range of 50 ° C. to 200 ° C., and it is preferable to use one kind of single solvent or two or more kinds of mixed solvents selected from the group of methyl ethyl ketone, dimethylacetamide, dimethylformamide and the like. This is to obtain a good semi-cured resin film as described above. And the range of the resin solid content shown here is a range in which the film thickness can be controlled to the most accurate one when applied to the surface of the copper foil. When the resin solid content is less than 30 wt%, the viscosity is too low, and it flows immediately after application to the copper foil surface, making it difficult to ensure film thickness uniformity. On the other hand, when the resin solid content exceeds 70 wt%, the viscosity increases and it becomes difficult to form a thin film on the surface of the copper foil. In addition, when the resin flow is less than 5%, it is not preferable because air entrapment or the like occurs in the uneven portions of the inner layer circuit on the surface of the inner layer core material. On the other hand, when the resin flow exceeds 35%, the resin flow becomes too large, and the thickness of the insulating layer formed using the resin layer of the carrier-attached copper foil having the resin layer becomes nonuniform.
When the said cured resin layer and a semi-hardened resin layer are provided in copper foil with a carrier, the copper foil with a carrier which has a resin layer suitable for a solid molded printed wiring board manufacture use can be provided.

Moreover, it is preferable that the said resin layer is equipped with the protective film which can be peeled off to the single side | surface of the said semi-hardened insulating layer. A known insulating film or resin film can be used for the protective film. For example, a polyethylene terephthalate film, a polyethylene naphthalate film, a metal foil, or the like can be used for the protective film.
The resin layer may contain a curing agent and / or a curing accelerator.
The resin layer may be a resin layer formed of a resin composition having a resin flow of 5% or less when measured according to MIL-P-13949G in the MIL standard.
The resin layer is 5 parts by weight to 50 parts by weight of an epoxy resin (including a curing agent), 50 parts by weight to 95 parts by weight of a polyether sulfone soluble in a solvent, and curing that is added in an appropriate amount as necessary. What was comprised using the resin composition which consists of an accelerator may be used.

In addition, the resin layer contains the following components A to D in a range of the following content (provided that the resin composition is 100 parts by weight excluding the epoxy resin curing agent). It may be formed of a composition.
Component A: Polyamideimide resin having a tensile strength of 200 MPa or more at 25 ° C. 10 to 20 parts by weight Component B: Polyamideimide resin having a tensile strength of 100 MPa or less at 25 ° C. 20 to 40 parts by weight Component C: Epoxy resin component D: Epoxy resin curing agent The resin layer may be a semi-cured resin layer.

  The component A is a polyamideimide resin having a tensile strength of 200 MPa or more at 25 ° C. Here, “polyamideimide resin having a tensile strength of 200 MPa or more” means, for example, trimellitic acid anhydride, benzophenone tetracarboxylic acid anhydride and vitorylene diisocyanate as N-methyl-2-pyrrolidone or / and N, N— A resin obtained by heating in a solvent such as dimethylacetamide. Here, although the upper limit is not described, the upper limit of the tensile strength of the polyamide-imide resin is about 500 MPa in consideration of the tensile strength of the polyimide amide resin. In addition, the tensile strength of the polyamide-imide resin according to Component A and Component B in the present invention was determined from the polyamide-imide resin solution using a film-shaped No. 2 test piece as defined in JIS K7113 (total length 115 mm, distance between chucks 80 ± 5 mm, parallel part length) The thickness is 33 ± 2 mm, the parallel part width is 6 ± 0.4 mm, and the film thickness is 1 to 3 mm.

The component B is a polyamideimide resin having a tensile strength at 25 ° C. of 100 MPa or less. Here, “polyamideimide resin having a tensile strength of 100 MPa or less” means, for example, trimellitic anhydride, diphenylmethane diisocyanate and carboxyl group-terminated acrylonitrile-butadiene rubber with N-methyl-2-pyrrolidone and / or N, N-dimethyl. It is obtained by heating in a solvent such as acetamide.
The content of component C (epoxy resin) may be 40 to 70 parts by weight when the resin composition is 100 parts by weight. In addition, the above-mentioned epoxy resin can be used as an epoxy resin. The content of component D (epoxy resin curing agent) is preferably such that the resin composition contains an imidazole compound that can cure the epoxy resin. The semi-cured resin layer is preferably a semi-cured resin layer having a volatile content of less than 1 wt% formed from the resin composition. When the above content is satisfied, even if the carrier-attached copper foil having a resin layer is stored or transported in a roll shape, the transfer of the organic solvent from the resin layer of the carrier-attached copper foil having the resin layer to the carrier-attached copper foil can be performed. In addition, it is possible to obtain a copper foil with a carrier provided with a resin layer having excellent heat resistance and adhesive properties with the copper foil with a carrier.

  Here, as the imidazole compound, known compounds can be used. For example, 2-undecylimidazole, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, 1- Cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl- 5-hydroxymethylimidazole etc. are mentioned, These can be used individually or in mixture.

The amount of the curing agent to be added is inevitably determined according to the amount of epoxy resin, the curing rate required in the process, and the like. The amount of the imidazole compound added as a curing agent is described as 100 parts by weight of the resin composition. In the range of 0.01 to 2 parts by weight in the resin composition. And the compounding quantity of an imidazole compound has more preferable 0.02 weight part-1.5 weight part, More preferably, it is 0.03 weight part-1.0 weight part. When the compounding amount of the imidazole compound is less than 0.01 parts by weight, curing may be insufficient in consideration of the content of the epoxy resin, and the resin layers of the copper foil with a carrier having a resin layer may be combined. Adhesive strength at the time of bonding decreases. On the other hand, when the compounding amount of the imidazole compound exceeds 2 parts by weight, the curing reaction of the epoxy resin is accelerated, the resin layer after curing becomes brittle, the strength of the cured resin film, the resin layers of the copper foil with resin, Adhesiveness at the time of pasting may deteriorate.
In addition, the epoxy resin of component C, the epoxy resin curing agent of component D, the known epoxy resin of component C, the epoxy resin curing agent of component D or the epoxy resin of component C described in this specification, the epoxy resin of component D A curing agent can be used.

The resin layer is a resin composition having moisture absorption resistance in a semi-cured state, and the resin composition includes the following components A to E, and contains phosphorus atoms when the resin composition weight is 100% by weight. You may form using the resin composition contained in 0.5 weight%-3.0 weight%.
Component A: One or more selected from the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol AD type epoxy resin having an epoxy equivalent of 200 or less and liquid at 25 ° C.
Component B: A linear polymer having a crosslinkable functional group.
Component C: Crosslinking agent.
D component: Imidazole-based epoxy resin curing agent.
E component: Phosphorus-containing epoxy resin.
The linear polymer having a functional group as the component B is preferably a polymer component soluble in an organic solvent having a boiling point of 50 ° C. to 200 ° C. Specifically, polyvinyl acetal resin, phenoxy resin, polyethersulfone resin, polyamideimide resin, and the like. The linear polymer having a crosslinkable functional group is preferably used in a blending ratio of 3 to 30 parts by weight when the resin composition is 100 parts by weight. When the epoxy resin is less than 3 parts by weight, the resin flow may increase. As a result, a large amount of resin powder may be observed from the end of the produced copper-clad laminate, and the moisture absorption resistance of the resin layer in a semi-cured state may not be improved. On the other hand, even if it exceeds 30 parts by weight, the resin flow may be small, and defects such as voids may easily occur in the insulating layer of the produced copper-clad laminate.

Specific examples of the organic solvent having a boiling point of 50 ° C. to 200 ° C. mentioned here include groups such as methanol, ethanol, methyl ethyl ketone, toluene, propylene glycol monomethyl ether, dimethylformamide, dimethylacetamide, cyclohexanone, ethyl cellosolve, and the like. 1 type of single solvent chosen from these, or 2 or more types of mixed solvents. When the boiling point is less than 50 ° C., the solvent is greatly diffused by heating, and it may be difficult to obtain a good semi-cured state from the resin varnish to the semi-cured resin. On the other hand, when the boiling point exceeds 200 ° C., the solvent may easily remain in a semi-cured state. In addition, the normally required volatilization rate may not be satisfied, and industrial productivity may not be satisfied.
The component C is a crosslinking agent for causing a crosslinking reaction between the component B and the epoxy resin. As this crosslinking agent, it is preferable to use a urethane-based resin. This cross-linking agent is added according to the mixing amount of the B component, and it is considered that there is no need to specify the mixing ratio strictly strictly. However, when the resin composition is 100 parts by weight, it is preferably used at a blending ratio of 10 parts by weight or less. If the C component which is a urethane-based resin is present exceeding 10 parts by weight, the moisture absorption resistance of the resin layer in the semi-cured state is deteriorated, and the cured resin layer becomes brittle.

  Component D is an imidazole epoxy resin curing agent. In the resin composition according to the present invention, it is preferable to selectively use an imidazole epoxy resin curing agent from the viewpoint of improving the moisture absorption resistance of the semi-cured resin layer. Among these, it is preferable to use an imidazole-based epoxy resin curing agent having the structural formula shown in Chemical Formula 7 below. By using the imidazole-type epoxy resin curing agent having the structural formula shown in Chemical Formula 7, the moisture absorption resistance of the semi-cured resin layer can be remarkably improved, and the long-term storage stability is excellent. In addition, it is preferable to employ | adopt the optimal amount obtained experimentally as the addition amount of the epoxy resin hardening | curing agent with respect to an epoxy resin rather than calculating from a reaction equivalent. This is because the imidazole-based epoxy resin curing agent performs a catalytic function in curing the epoxy resin and contributes as a reaction initiator that causes a self-polymerization reaction of the epoxy resin in the initial stage of the curing reaction.

The phosphorus-containing epoxy resin as the E component is an epoxy resin obtained as a derivative from 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide having two or more epoxy groups in the molecule. It is preferable.
The structural formula of 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is as follows.

  The epoxy resin obtained as a derivative from 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is converted to 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide. After reacting naphthoquinone or hydroquinone to obtain a compound represented by the following chemical formula 9 (HCA-NQ) or chemical formula 10 (HCA-HQ), an epoxy resin is reacted with the OH group portion to obtain a phosphorus-containing epoxy resin. Is.

  The phosphorus-containing epoxy resin, which is the E component obtained using the above-mentioned compound as a raw material, is used by mixing one or two compounds having the structural formula shown in any one of the following chemical formulas 11 to 13 Is preferred. This is because the resin quality in a semi-cured state is excellent in stability, and at the same time, the flame retardant effect is high.

  When the resin composition has a resin composition weight of 100 parts by weight, the A component is 3 parts by weight to 20 parts by weight, the B component is 3 parts by weight to 30 parts by weight, and the resin composition weight is 100% by weight. The resin composition is preferably a resin composition in which parts by weight of the E component are determined so that the phosphorus atom is in the range of 0.5 wt% to 3.0 wt%.

You may form the said resin layer using the resin composition containing each component of the following A component-F component.
Component A: One or more selected from the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol AD type epoxy resin having an epoxy equivalent of 200 or less and liquid at 25 ° C.
Component B: A linear polymer having a crosslinkable functional group.
Component C: Crosslinking agent (provided that the component A can be omitted when the component A functions as a crosslinking agent for the component B). Component D: 4,4′-diaminodiphenylsulfone or 2,2-bis (4- (4-aminophenoxy) phenyl) propane.
E component: Flame retardant epoxy resin.
F component: Polyfunctional epoxy resin.
G component: A curing accelerator.
The linear polymer having a crosslinkable functional group as the component B is preferably a polyvinyl acetal resin or a polyamideimide resin.
It is preferable that the crosslinking agent as the component C is a urethane resin.
The flame retardant epoxy resin as the component E is a brominated epoxy resin having the structural formula shown in Chemical formula 14 obtained as a derivative from tetrabromobisphenol A having two or more epoxy groups in the molecule, and chemical formula 15 shown below. It is preferable to use one or two brominated epoxy resins having the structural formula shown in FIG.

The flame retardant epoxy resin which is the E component uses a phosphorus-containing epoxy resin which is a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative having two or more epoxy groups in the molecule. It is preferable.
The flame retardant epoxy resin that is the component E is preferably used by mixing one or two phosphorus-containing epoxy resins having the structural formula shown in any one of the following chemical formulas 16 to 18.

It is preferable to use an ortho cresol novolac type epoxy resin as the polyfunctional epoxy resin of the F component.
When the weight of the resin composition for forming the resin layer is 100 parts by weight, the A component is 3 to 20 parts by weight, the B component is 3 to 30 parts by weight, and the C component is 3 parts by weight. 10 parts by weight (0 to 10 parts by weight when the A component functions as a crosslinking agent for the B component), 5 to 20 parts by weight of the D component, and 3 to 20 parts by weight of the F component When the weight of the resin composition is 100% by weight, it is preferable to determine the weight part of the E component so that the bromine atom derived from the E component is contained in the range of 12% by weight to 18% by weight.
When the weight of the resin composition for forming the resin layer is 100 parts by weight, the A component is 3 to 20 parts by weight, the B component is 3 to 30 parts by weight, and the C component is 3 parts by weight. 10 parts by weight (0 to 10 parts by weight when the A component functions as a crosslinking agent for the B component), 5 to 20 parts by weight of the D component, and 3 to 20 parts by weight of the F component When the weight of the resin composition is 100% by weight, it is preferable that the part by weight of the E component is determined so that the phosphorus atom derived from the E component is contained in the range of 0.5% by weight to 3.0% by weight. .
The resin composition for forming the resin layer preferably contains a curing accelerator as the G component.
The said resin layer prepares the resin varnish used for formation of a resin layer with the procedure of the following processes a and process b, applies the said resin varnish to the surface of copper foil with a carrier, and is dried, and average thickness of 5 micrometers-100 micrometers It is preferable to form a semi-cured resin film.
Step a: A component to F component among the A component, B component, C component (may be omitted when the A component functions as a crosslinking agent for the B component), D component, E component, F component, G component When the weight of the resin composition containing as an essential component is 100% by weight, the bromine atom derived from the E component is in the range of 12% to 18% by weight or the phosphorus atom is 0.5% to 3.0% by weight. Each component is mixed so that it may be contained in a range to obtain a resin composition.
Process b: The said resin composition is melt | dissolved using an organic solvent, and it is set as the resin varnish whose resin solid content is 25 to 50 weight%.

The resin layer is preferably formed using a resin composition containing the following components A to E.
Component A: An epoxy resin comprising one or more selected from the group consisting of a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, and a bisphenol AD type epoxy resin that have an epoxy equivalent of 200 or less and are liquid at room temperature.
B component: High heat resistant epoxy resin.
Component C: Flame retardant epoxy resin containing phosphorus.
Component D: A rubber-modified polyamide-imide resin modified with a liquid rubber component having a property that is soluble in a solvent having a boiling point in the range of 50 ° C. to 200 ° C.
Component E: A resin curing agent comprising one or more of a biphenyl type phenol resin and a phenol aralkyl type phenol resin.
The resin layer is preferably formed using a resin composition containing a phosphorus-containing flame retardant having no reactivity with an epoxy resin as the F component in addition to the components A to E.

  The component A is an epoxy resin composed of one or more selected from the group consisting of a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, and a bisphenol AD type epoxy resin that have an epoxy equivalent of 200 or less and are liquid at room temperature. Here, the bisphenol-based epoxy resin is selectively used because it has good compatibility with the D component (rubber-modified polyamideimide resin) described later, and it is easy to impart appropriate flexibility to the resin film in a semi-cured state. It is. When the epoxy equivalent exceeds 200, the resin becomes semi-solid at room temperature, and the flexibility in the semi-cured state is decreased, which is not preferable. Furthermore, if it is the above-mentioned bisphenol-type epoxy resin, 1 type may be used independently or 2 or more types may be used in mixture. In addition, when two or more kinds are mixed and used, there is no particular limitation with respect to the mixing ratio.

  This epoxy resin is preferably used in a blending ratio of 3 parts by weight to 20 parts by weight when the resin composition is 100 parts by weight. When the epoxy resin is less than 3 parts by weight, the thermosetting property is not sufficiently exhibited, and the function as a binder with the inner layer flexible printed wiring board and the adhesiveness with the copper foil as the resin-coated copper foil are sufficient. It becomes difficult to do. On the other hand, when the amount exceeds 20 parts by weight, the viscosity of the resin varnish increases from the balance with other resin components, and when the resin-coated copper foil is produced, the resin film with a uniform thickness is formed on the copper foil surface. Formation becomes difficult. In addition, considering the amount of addition with a D component (rubber-modified polyamideimide resin) described later, sufficient toughness as a cured resin layer cannot be obtained.

  The B component is a “high heat resistant epoxy resin” having a high so-called glass transition point. The “high heat-resistant epoxy resin” referred to here is preferably a polyfunctional epoxy resin such as a novolac-type epoxy resin, a cresol novolac-type epoxy resin, a phenol novolac-type epoxy resin, or a naphthalene-type epoxy resin. And it is preferable to use this B component in the range of 3 weight part-30 weight part, when a resin composition is 100 weight part. When the component B is less than 3 parts by weight, the resin composition cannot have a high Tg. On the other hand, when the B component exceeds 30 parts by weight, the cured resin becomes brittle and the flexibility is completely impaired, which is not preferable for flexible printed wiring board applications. More preferably, by using the B component in the range of 10 to 20 parts by weight, it is possible to stably achieve both high Tg of the resin composition and good flexibility of the cured resin.

  The component C is a so-called halogen-free flame-retardant epoxy resin, and a phosphorus-containing flame-retardant epoxy resin is used. The phosphorus-containing flame-retardant epoxy resin is a general term for epoxy resins containing phosphorus in an epoxy skeleton. And when the phosphorus atom content of the resin composition according to the present application is 100% by weight of the resin composition, the phosphorus atom derived from component C can be in the range of 0.5% to 3.0% by weight. Any phosphorus-containing flame-retardant epoxy resin can be used. However, it is possible to use a phosphorus-containing flame-retardant epoxy resin that is a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative having two or more epoxy groups in the molecule in a semi-cured state. It is preferable because of its excellent resin quality stability and high flame retardant effect. For reference, the structural formula of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is shown in Chemical Formula 19.

  And when the phosphorus containing flame-retardant epoxy resin which is a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative is illustrated concretely, use of the compound provided with the structural formula shown in Chemical formula 20 preferable. It is preferable because it is excellent in the stability of the resin quality in a semi-cured state and at the same time has a high flame retardant effect.

  In addition, as the phosphorus-containing flame-retardant epoxy resin of component C, a compound having the structural formula shown in Chemical formula 21 shown below is also preferable. Like the phosphorus-containing flame-retardant epoxy resin shown in Chemical formula 20, it is preferable because it is excellent in the stability of the resin quality in the semi-cured state and at the same time can impart high flame retardancy.

  Furthermore, as the phosphorus-containing flame retardant epoxy resin of component C, a compound having the structural formula shown in Chemical Formula 22 shown below is also preferable. Like the phosphorus-containing flame-retardant epoxy resin shown in Chemical Formula 20 and Chemical Formula 21, it is preferable because it is excellent in the stability of the resin quality in the semi-cured state and at the same time can impart high flame retardancy.

  The epoxy resin obtained as a derivative from 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is converted to 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide. After reacting with naphthoquinone or hydroquinone to obtain a compound represented by the following chemical formula 23 (HCA-NQ) or chemical formula 24 (HCA-HQ), an epoxy resin is reacted with the OH group portion to obtain a phosphorus-containing flame-retardant epoxy. What was made into resin is mentioned.

  Here, the resin composition in the case of using the phosphorus-containing flame-retardant epoxy resin is not limited to two types of phosphorus-containing flame-retardant epoxy resins even if one of the phosphorus-containing flame-retardant epoxy resins as the C component is used alone. May be used in combination. However, in consideration of the total amount of the phosphorus-containing flame-retardant epoxy resin as the C component, when the weight of the resin composition is 100% by weight, the phosphorus atom derived from the C component is 0.5% to 3.0% by weight. It is preferable to add so that it may become this range. The phosphorus-containing flame-retardant epoxy resin has different amounts of phosphorus atoms contained in the epoxy skeleton depending on the type. Therefore, it is possible to define the phosphorus atom content as described above and replace it with the added amount of the C component. However, the component C is usually used in the range of 5 to 50 parts by weight when the resin composition is 100 parts by weight. In the case where the C component is less than 5 parts by weight, it is difficult to make the phosphorus atom derived from the C component 0.5% by weight or more in consideration of the blending ratio of other resin components, and to obtain flame retardancy. I can't. On the other hand, even if the C component exceeds 50 parts by weight, the effect of improving flame retardancy is saturated, and at the same time, the cured resin layer becomes brittle, which is not preferable.

  “High Tg” and “flexibility” of the cured resin described above are generally inversely proportional characteristics. At this time, there are phosphorus-containing flame-retardant epoxy resins that contribute to improving the flexibility of the cured resin and those that contribute to a higher Tg. Therefore, rather than using one type of phosphorus-containing flame-retardant epoxy resin, “phosphorus-containing flame-retardant epoxy resin that contributes to higher Tg” and “phosphorus-containing flame-retardant epoxy resin that contributes to improved flexibility” By mixing and using in a well-balanced manner, it is possible to obtain a resin composition suitable for flexible printed wiring board applications.

  Component D is a rubber-modified polyamideimide resin that is soluble in a solvent having a boiling point in the range of 50 ° C. to 200 ° C. and modified with a liquid rubber component. This rubber-modified polyamideimide resin is obtained by reacting a polyamideimide resin and a rubber resin. The rubber-modified polyamide-imide resin and the rubber-like resin used here are reacted for the purpose of improving the flexibility of the polyamide-imide resin itself. That is, the polyamideimide resin and the rubber resin are reacted to replace a part of the acid component (cyclohexanedicarboxylic acid or the like) of the polyamideimide resin with the rubber component. The rubber component is described as a concept including natural rubber and synthetic rubber, and the latter synthetic rubber includes styrene-butadiene rubber, butadiene rubber, butyl rubber, ethylene-propylene rubber and the like. Furthermore, from the viewpoint of ensuring heat resistance, it is also useful to selectively use a synthetic rubber having heat resistance such as nitrile rubber, chloroprene rubber, silicon rubber, urethane rubber and the like. Since these rubber resins react with the polyamide-imide resin to produce a copolymer, it is desirable to have various functional groups at both ends. In particular, it is useful to use CTBN (carboxy group-terminated butadiene nitrile) having a carboxyl group. In addition, the said rubber component may copolymerize only 1 type or may copolymerize 2 or more types. Further, when a rubber component is used, it is preferable to use a rubber component having a number average molecular weight of 1000 or more from the viewpoint of stabilization of the flexibility.

  Solvents used for dissolving the polyamideimide resin and the rubbery resin when polymerizing the rubber-modified polyamideimide resin include dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, dimethylsulfoxide, nitromethane, nitroethane, tetrahydrofuran , Cyclohexanone, methyl ethyl ketone, acetonitrile, γ-butyrolactone, and the like are preferably used alone or in combination. And in order to raise | generate a polymerization reaction, it is preferable to employ | adopt the polymerization temperature of the range of 80 to 200 degreeC. When a solvent having a boiling point of more than 200 ° C. is used for these polymerizations, it is preferable that the solvent be replaced with a solvent having a boiling point in the range of 50 ° C. to 200 ° C., depending on the application.

  Here, examples of the solvent having a boiling point in the range of 50 ° C. to 200 ° C. include one single solvent or two or more mixed solvents selected from the group of methyl ethyl ketone, dimethylacetamide, dimethylformamide and the like. When the boiling point is lower than 50 ° C., the solvent is greatly diffused by heating, and it is difficult to obtain a good semi-cured state when the resin varnish is changed to a semi-cured resin. On the other hand, when the boiling point exceeds 200 ° C., bubbling is likely to occur when the resin varnish is used as a semi-cured resin, and it is difficult to obtain a good semi-cured resin film.

  Among the rubber-modified polyamideimide resins used in the resin composition according to the present invention, when the weight of the rubber-modified polyamideimide resin is 100% by weight, the copolymerization amount of the rubber component is 0.8% by weight or more. preferable. When the copolymerization amount is less than 0.8% by weight, the rubber-modified polyamide-imide resin lacks flexibility when the resin layer formed using the resin composition according to the present invention is cured, Since the adhesiveness with copper foil also falls, it is not preferable. More preferably, the copolymerization amount of the rubber component is 3% by weight or more, more preferably 5% by weight or more. Empirically, there is no particular problem even if the amount of the rubber component added is increased beyond 40% by weight. However, since the effect of improving the flexibility of the cured resin layer is saturated, resources are wasted, which is not preferable.

  The rubber-modified polyamideimide resin described above is required to be soluble in a solvent. This is because preparation as a resin varnish is difficult unless it is soluble in a solvent. This rubber-modified polyamideimide resin is used in a blending ratio of 10 to 40 parts by weight, when the weight of the resin composition is 100 parts by weight. When the rubber-modified polyamide-imide resin is less than 10 parts by weight, the flexibility of the cured resin layer is difficult to improve, becomes brittle, and tends to cause micro cracks in the resin layer. On the other hand, adding more than 40 parts by weight of the rubber-modified polyamideimide resin will not cause any particular problem, but the flexibility of the cured resin layer will not be further improved, and the cured resin will have a higher Tg. Absent. Therefore, considering the economy, it can be said that 40 parts by weight is the upper limit.

  The E component resin curing agent will be described. The resin hardening | curing agent said here uses 1 type, or 2 or more types of a biphenyl type phenol resin and a phenol aralkyl type phenol resin. Generally, the addition amount of the resin curing agent is naturally derived from the reaction equivalent to the resin to be cured, and does not require any particular quantitative limitation. However, the E component in the case of the resin composition according to the present invention is preferably used in the range of 20 to 35 parts by weight when the resin composition is 100 parts by weight. When the E component is less than 20 parts by weight, considering the resin composition, a sufficient cured state cannot be obtained, and flexibility as a cured resin cannot be obtained. On the other hand, when the E component exceeds 35 parts by weight, the moisture absorption resistance of the cured resin layer tends to deteriorate, which is not preferable.

  The phosphorus-containing flame retardant for the F component will be described. This phosphorus-containing flame retardant is an optional additive component and does not need to contribute to the curing reaction of the resin, and is simply used to greatly improve the flame retardancy. As such a phosphorus-containing flame retardant, it is preferable to use a halogen-free flame retardant of a phosphazene compound. Therefore, this F component is used in the range of 0 to 7 parts by weight. Here, “0 part by weight” is described in order to clarify that the F component may not be used and is an optional additive component. On the other hand, even if the F component exceeds 7 parts by weight, no significant improvement in flame retardancy can be expected.

When the weight of the resin composition is 100 parts by weight, the A component is 3 to 20 parts by weight, the B component is 3 to 30 parts by weight, the C component is 5 to 50 parts by weight, and the D component is 10 parts by weight. Parts by weight to 40 parts by weight, E component from 20 parts by weight to 35 parts by weight, F component from 0 parts by weight to 7 parts by weight, and when the resin composition weight is 100% by weight, the resin composition contains C component The derived phosphorus atom is preferably contained in the range of 0.5 wt% to 3.0 wt%.
The component D is a liquid rubber component having a property soluble in one single solvent or two or more mixed solvents selected from the group of methyl ethyl ketone, dimethylacetamide, and dimethylformamide having a boiling point in the range of 50 ° C to 200 ° C. A rubber-modified polyamide-imide resin modified with
The rubber-modified polyamideimide resin as the component D is preferably obtained by reacting polyamideimide with a rubber resin.
The resin layer is prepared by adding a solvent to the above-described resin composition so that the resin solid content is in the range of 30% by weight to 70% by weight, and measured according to MIL-P-13949G in the MIL standard. Is preferably formed using a resin composition (resin varnish) capable of forming a semi-cured resin layer in the range of 1% to 30%.
For the resin layer, a resin varnish to be used for forming the resin layer is prepared by the following steps a and b, and the resin varnish is applied to the surface of the copper foil and dried to be half the thickness of 10 μm to 50 μm. It is preferably formed as a cured resin layer.
Step a: A component is 3 to 20 parts by weight, B component is 3 to 30 parts by weight, C component is 5 to 50 parts by weight, D component is 10 to 40 parts by weight, and E component is In the range of 20 parts by weight to 35 parts by weight and F component in the range of 0 part by weight to 7 parts by weight, each component is mixed, and the phosphorus atom derived from the C component is contained in the range of 0.5% by weight to 3.0% by weight. The resin composition is made.
Process b: The said resin composition is melt | dissolved using an organic solvent, and it is set as the resin varnish whose resin solid content amount is 30 weight%-70 weight%.

The resin layer is a resin composition used for forming an adhesive layer for multilayering an inner layer flexible printed wiring board, and is formed of a resin composition containing each of the following components A to E: Is preferred.
A component: Solid high heat-resistant epoxy resin having a softening point of 50 ° C. or higher (excluding biphenyl type epoxy resin).
B component: 1 of biphenyl type phenol resin, phenol aralkyl type phenol resin
Epoxy resin curing agent comprising two or more species.
Component C: A rubber-modified polyamideimide resin soluble in a solvent having a boiling point in the range of 50 ° C to 200 ° C.
D component: An organic phosphorus-containing flame retardant.
E component: Biphenyl type epoxy resin.
The resin composition used for forming the resin layer preferably contains a phosphorus-containing flame-retardant epoxy resin as the F component in addition to the components A to E.
The resin composition used to form the resin layer is selected from the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol AD type epoxy resin having an epoxy equivalent of 200 or less and liquid at room temperature as the G component. It is preferable that the epoxy resin which consists of 1 type (s) or 2 or more types is further included.
It is preferable that the resin composition used for forming the resin layer further contains a low-elasticity material made of a thermoplastic resin and / or a synthetic rubber as the H component.
The solid high heat resistant epoxy resin in which the softening point of the component A is 50 ° C. or higher is one or more of cresol novolac type epoxy resin, phenol novolac type epoxy resin, and naphthalene type epoxy resin. Is preferred.
Resin further including a high heat-resistant epoxy resin composed of one or more of a novolak type epoxy resin, a cresol novolak type epoxy resin, a phenol novolak type epoxy resin, and a naphthalene type epoxy resin that is liquid at room temperature as the component A The resin layer is preferably formed using a composition.
When the weight of the resin composition for forming the resin layer is 100 parts by weight, the A component is 3 to 30 parts by weight, the B component is 13 to 35 parts by weight, and the C component is 10 parts by weight. It is preferable that 50 parts by weight, the D component is 3 to 16 parts by weight, and the E component is 5 to 35 parts by weight.

  A resin varnish prepared by adding a solvent to the resin composition so that the resin solid content is in the range of 30 wt% to 70 wt%. When a semi-cured resin layer is formed, the MIL-P-13949G in the MIL standard In conformity, it is preferable to form the resin layer using a resin varnish characterized by having a resin flow in a range of 0% to 10% when measured at a resin thickness of 55 μm.

The resin layer has a thickness of 10 μm to 80 μm by preparing a resin varnish used for forming the resin layer in the following steps a and b, applying the resin varnish to the surface of the copper foil with a carrier, and drying. The semi-cured resin layer is preferably formed.
Step a: When the weight of the resin composition is 100 parts by weight, the A component is 3 to 30 parts by weight, the B component is 13 to 35 parts by weight, the C component is 10 to 50 parts by weight, and the D component Is a resin composition containing each component in the range of 3 to 16 parts by weight and E component in the range of 5 to 35 parts by weight.
Process b: The said resin composition is melt | dissolved using an organic solvent, and it is set as the resin varnish whose resin solid content amount is 30 weight%-70 weight%.

The component A is a solid high heat resistant epoxy resin having a softening point of 50 ° C. or higher. The component A is an epoxy resin having a high so-called glass transition temperature Tg. The reason why a solid high heat resistant epoxy resin having a softening point of 50 ° C. or higher among the epoxy resins is used is that the glass transition temperature Tg is high, and a high heat resistance effect can be obtained by adding a small amount.

The “solid high heat resistant epoxy resin having a softening point of 50 ° C. or higher” mentioned here is one or more of cresol novolac type epoxy resin, phenol novolac type epoxy resin, and naphthalene type epoxy resin. It is preferable.

  In addition to the solid high heat-resistant epoxy resin having a softening point of 50 ° C. or higher, the component A further includes a novolac type epoxy resin, a cresol novolac type epoxy resin, a phenol novolak type epoxy resin, and a naphthalene type. It is good also as what contains the highly heat-resistant epoxy resin which consists of any 1 type or 2 types or more of an epoxy resin. As described above, as the component A, a high heat-resistant epoxy composed of one or more of a novolak type epoxy resin, a cresol novolak type epoxy resin, a phenol novolak type epoxy resin, and a naphthalene type epoxy resin that is liquid at room temperature. If the resin is contained, the effect of further improving the glass transition temperature Tg and improving the B stage cracking can be enhanced.

  The component A is preferably used in the range of 3 to 30 parts by weight when the resin composition is 100 parts by weight. When the component A is less than 3 parts by weight, it is difficult to increase the Tg of the resin composition. On the other hand, when the component A exceeds 30 parts by weight, the cured resin layer becomes brittle and the flexibility is completely impaired, which is not preferable for use as a flexible printed wiring board. More preferably, the component A is used in the range of 10 to 25 parts by weight, so that both high Tg of the resin composition and good flexibility of the resin layer after curing can be stably achieved.

Component B is an epoxy resin curing agent composed of one or more of a biphenyl type phenol resin and a phenol aralkyl type phenol resin. The addition amount of the epoxy resin curing agent is naturally derived from the reaction equivalent to the resin to be cured, and does not require any particular quantitative limitation. However, in the case of the resin composition according to the present invention, the component B is preferably used in the range of 13 parts by weight to 35 parts by weight when the resin composition is 100 parts by weight. When this B component is less than 13 parts by weight, considering the resin composition of the present invention, it becomes impossible to obtain a sufficiently cured state, and it becomes impossible to obtain the flexibility of the cured resin layer. On the other hand, when the component B exceeds 35 parts by weight, the moisture absorption resistance of the cured resin layer tends to deteriorate, which is not preferable.
A specific example of the biphenyl type phenol resin is shown in Chemical Formula 25.

  A specific example of the phenol aralkyl type phenol resin is shown in Chemical Formula 26.

  Component C is a rubber-modified polyamideimide resin that is soluble in a solvent having a boiling point in the range of 50 ° C to 200 ° C. By mix | blending the said C component, while improving a flexible performance, the effect which suppresses a resin flow is acquired. This rubber-modified polyamideimide resin is obtained by reacting a polyamideimide resin and a rubber resin, and is performed for the purpose of improving the flexibility of the polyamideimide resin itself. That is, the polyamideimide resin and the rubber resin are reacted to replace a part of the acid component (cyclohexanedicarboxylic acid or the like) of the polyamideimide resin with the rubber component. The rubber component is described as a concept including natural rubber and synthetic rubber. Examples of the latter synthetic rubber include styrene-butadiene rubber, butadiene rubber, butyl rubber, ethylene-propylene rubber, and acrylonitrile butadiene rubber. Furthermore, from the viewpoint of ensuring heat resistance, it is also useful to selectively use a synthetic rubber having heat resistance such as nitrile rubber, chloroprene rubber, silicon rubber, urethane rubber and the like. Since these rubber-like resins react with the polyamide-imide resin to produce a copolymer, it is desirable to have various functional groups at both ends. In particular, it is useful to use CTBN (carboxy group-terminated butadiene nitrile rubber) having a carboxyl group. In addition, the said rubber component may copolymerize only 1 type or may copolymerize 2 or more types. Further, when a rubber component is used, it is preferable to use a rubber component having a number average molecular weight of 1000 or more from the viewpoint of stabilization of flexibility.

  When polymerizing the rubber-modified polyamideimide resin, the solvents used for dissolving the polyamideimide resin and the rubbery resin include dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, nitromethane, nitroethane, and tetrahydrofuran. , Cyclohexanone, methyl ethyl ketone, acetonitrile, γ-butyrolactone, and the like are preferably used alone or in combination. And in order to raise | generate a polymerization reaction, it is preferable to employ | adopt the polymerization temperature of the range of 80 to 200 degreeC. When a solvent having a boiling point of more than 200 ° C. is used for these polymerizations, it is preferable that the solvent be replaced with a solvent having a boiling point in the range of 50 ° C. to 200 ° C., depending on the application.

  Here, examples of the solvent having a boiling point in the range of 50 ° C. to 200 ° C. include one single solvent or two or more mixed solvents selected from the group of methyl ethyl ketone, dimethylacetamide, dimethylformamide and the like. When the boiling point is lower than 50 ° C., the solvent is greatly diffused by heating, and it is difficult to obtain a good semi-cured state when the resin varnish is changed to a semi-cured resin. On the other hand, when the boiling point exceeds 200 ° C., when the semi-cured resin is used from the state of the resin varnish, it is difficult to obtain a good semi-cured resin layer because the solvent is difficult to dry.

  Among the rubber-modified polyamideimide resins used in the resin composition according to the present invention, when the weight of the rubber-modified polyamideimide resin is 100% by weight, the copolymerization amount of the rubber component may be 0.8% by weight or more. preferable. When the copolymerization amount is less than 0.8% by weight, the rubber-modified polyamide-imide resin lacks flexibility when the resin layer formed using the resin composition according to the present invention is cured, Since the adhesiveness with copper foil also falls, it is not preferable. More preferably, the copolymerization amount of the rubber component is 3% by weight or more, more preferably 5% by weight or more. Empirically, there is no particular problem even if the copolymerization amount exceeds 40% by weight. However, since the effect of improving the flexibility of the cured resin layer is saturated, resources are wasted, which is not preferable.

  The rubber-modified polyamide-imide resin described above is required to be soluble in a solvent. This is because preparation as a resin varnish is difficult unless it is soluble in a solvent. The rubber-modified polyamide-imide resin is used in a blending ratio of 10 to 50 parts by weight when the weight of the resin composition is 100 parts by weight. When the rubber-modified polyamideimide resin is less than 10 parts by weight, the resin flow suppressing effect is hardly exhibited. In addition, the cured resin layer becomes brittle and it is difficult to improve flexibility. As a result, there is an effect that microcracks of the resin layer are likely to occur. On the other hand, when the rubber-modified polyamide-imide resin is added in an amount exceeding 50 parts by weight, the embedding property in the inner layer circuit is lowered, and as a result, voids are easily generated, which is not preferable.

  Component D is an organic phosphorus-containing flame retardant and is used to improve flame retardancy. Examples of organic phosphorus-containing flame retardants include phosphorus-containing flame retardants composed of phosphate esters and / or phosphazene compounds. The component D is preferably used in the range of 3 to 16 parts by weight when the resin composition is 100 parts by weight. When the content of the D component is less than 3 parts by weight, the flame retardancy effect cannot be obtained. On the other hand, even if the content of the D component exceeds 16 parts by weight, improvement in flame retardancy cannot be expected. In addition, more preferable content of D component is 5 weight part-14 weight part.

  In addition, when the resin composition according to the present invention is added so that the total content of phosphorus is in the range of 0.5 wt% to 5 wt% when the weight of the resin composition is 100 wt%, it is flame retardant. Is preferable.

  The E component is a biphenyl type epoxy resin. The biphenyl type epoxy resin contributes to improvement of so-called glass transition temperature Tg and flexibility. Examples of the biphenyl type epoxy resin include a biphenyl aralkyl type epoxy resin. The component E is preferably used in the range of 5 to 35 parts by weight when the resin composition is 100 parts by weight. When the content of the E component is less than 5 parts by weight, the effect of increasing the glass transition temperature Tg and the flexibility cannot be obtained. On the other hand, even if the content of the E component exceeds 35 parts by weight, it is not possible to expect a high Tg and an improvement in flexibility. In addition, more preferable content of E component is 7 weight part-25 weight part.

  In addition to the A component to the E component, if the resin composition includes a phosphorus-containing flame-retardant epoxy resin as the F component, the flame retardancy can be further improved. The phosphorus-containing flame-retardant epoxy resin is a general term for epoxy resins containing phosphorus in an epoxy skeleton, and is a so-called halogen-free flame-retardant epoxy resin. And phosphorus content which can make phosphorus atom derived from F component into the range of 0.1 weight%-5 weight% when the resin composition weight is 100 weight% about the phosphorus atom content of the resin composition concerning this application Any flame retardant epoxy resin can be used. However, using a phosphorus-containing flame retardant epoxy resin having two or more epoxy groups in the molecule, which is a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative, is a semi-cured state. It is preferable because it has excellent resin quality stability at the same time and has a high flame retardant effect. For reference, the structural formula of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is shown in Chemical Formula 27.

  This 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative, a phosphorus-containing flame-retardant epoxy resin having two or more epoxy groups in the molecule, is 9,10-dihydro-9. -Oxa-10-phosphaphenanthrene-10-oxide is reacted with naphthoquinone or hydroquinone to form a compound shown in the following chemical formula 28 or chemical formula 29, and then reacted with an epoxy resin at the OH group portion to make it difficult to contain phosphorus. What was made into the flammable epoxy resin is preferable.

  A specific example of a phosphorus-containing flame-retardant epoxy resin having two or more epoxy groups in the molecule, which is a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative, The use of a compound having the structural formula shown in 30, 31 or 32 is preferred.

  Here, when the phosphorus-containing flame-retardant epoxy resin is used, the resin composition may be one of the phosphorus-containing flame-retardant epoxy resins as the F component, or two or more phosphorus-containing flame-retardant epoxy resins. May be used in combination. However, considering the total amount of the phosphorus-containing flame-retardant epoxy resin as the F component, when the resin composition weight is 100% by weight, the phosphorus atom derived from the F component is in the range of 0.1% to 5% by weight. It is preferable to add so that it becomes. The phosphorus-containing flame-retardant epoxy resin has different amounts of phosphorus atoms contained in the epoxy skeleton depending on the type. Therefore, it is possible to define the content of phosphorus atoms as described above and replace it with the addition amount of the F component. However, the component F is usually used in the range of 5 to 50 parts by weight when the resin composition is 100 parts by weight. In the case where the F component is less than 5 parts by weight, it becomes difficult to make the phosphorus atom derived from the F component 0.1% by weight or more in consideration of the blending ratio of the other resin components. Can not get. On the other hand, even if the F component exceeds 50 parts by weight, the effect of improving flame retardancy is saturated, and at the same time, the cured resin layer becomes brittle.

  “High Tg” and “flexibility” of the cured resin layer described above are generally inversely proportional characteristics. At this time, there are phosphorus-containing flame-retardant epoxy resins that contribute to improving the flexibility of the cured resin layer and those that contribute to high Tg. Therefore, rather than using one type of phosphorus-containing flame-retardant epoxy resin, “phosphorus-containing flame-retardant epoxy resin that contributes to higher Tg” and “phosphorus-containing flame-retardant epoxy resin that contributes to improved flexibility” By mixing and using in a well-balanced manner, it is possible to obtain a resin composition suitable for flexible printed wiring board applications.

  The resin composition according to the present invention is further selected from the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol AD type epoxy resin having an epoxy equivalent of 200 or less and being liquid at room temperature as the G component. Or it is good also as what contains the epoxy resin which consists of 2 or more types. Here, the reason why the bisphenol-based epoxy resin is selectively used is that the compatibility with the component C (rubber-modified polyamideimide resin) is good, and it is easy to impart appropriate flexibility to the semi-cured resin layer. If the epoxy equivalent exceeds 200, the resin becomes semi-solid at room temperature, and the flexibility in the semi-cured state decreases, which is not preferable. Furthermore, if it is the above-mentioned bisphenol-type epoxy resin, 1 type may be used independently or 2 or more types may be used in mixture. In addition, when two or more kinds are mixed and used, there is no particular limitation with respect to the mixing ratio.

  This G component epoxy resin, when the resin composition is 100 parts by weight, exhibits a sufficient thermosetting property when used in a blending ratio of 2 to 15 parts by weight. It is preferable because the occurrence of a so-called warp phenomenon can be reduced, and the flexibility of the resin layer in a semi-cured state can be further improved. When the said epoxy resin exceeds 15 weight part, there exists a tendency for a flame retardance to fall from the balance with another resin component, or for the resin layer after hardening to become hard. Moreover, considering the amount of component C (rubber-modified polyamideimide resin) added, sufficient toughness for the cured resin layer cannot be obtained.

  The resin composition according to the present invention may further include a low-elasticity substance made of a thermoplastic resin and / or a synthetic rubber as the H component. By setting it as the resin composition containing H component, the crack in the semi-hardened state of a resin composition can be prevented, and the flexibility after hardening can be improved. Examples of the low-elasticity material as the H component include acrylonitrile butadiene rubber, acrylic rubber (acrylic ester copolymer), polybutadiene rubber, isoprene, hydrogenated polybutadiene, polyvinyl butyral, polyethersulfone, phenoxy, and polymer epoxy. And aromatic polyamides. One of these may be used alone, or two or more may be used in combination. In particular, acrylonitrile butadiene rubber is preferably used. Among the acrylonitrile butadiene rubbers, a carboxyl-modified product can take a crosslinked structure with an epoxy resin and improve the flexibility of the cured resin layer. As the carboxyl-modified product, it is preferable to use carboxy group-terminated nitrile butadiene rubber (CTBN), carboxy group-terminated butadiene rubber (CTB), or carboxy-modified nitrile butadiene rubber (C-NBR).

  The H component is preferably used at a blending ratio of 25 parts by weight or less when the resin composition is 100 parts by weight. If an H component in an amount exceeding 25 parts by weight is added, problems such as a decrease in glass transition temperature Tg, a decrease in solder heat resistance, a decrease in peel strength, and an increase in thermal expansion coefficient are undesirable.

  The resin composition according to the present invention can improve the flame retardancy and the glass transition temperature Tg by combining the above-described components A to E, and can prevent the heat resistance of the folding resistance. And sufficient flexibility can be obtained, without adding an inorganic filler like the conventional resin composition for adhesive agents. Furthermore, it is possible to prevent cracking in a semi-cured state and powder falling off during punching.

  Resin varnish according to the present invention: The resin varnish according to the present invention is prepared by adding a solvent to the above resin composition so that the resin solid content is in the range of 30 wt% to 70 wt%. The semi-cured resin layer formed with this resin varnish has a resin flow in the range of 0% to 10% when measured with a resin thickness of 55 μm according to MIL-P-13949G in the MIL standard. Features. As the solvent mentioned here, one kind of single solvent selected from the group of methyl ethyl ketone, dimethylacetamide, dimethylformamide, etc., which is a solvent having a boiling point in the range of 50 ° C. to 200 ° C., or a mixed solvent of two or more kinds is used. It is preferable. This is for obtaining a good semi-cured resin layer as described above. And the range of the resin solid content shown here is a range in which the film thickness can be controlled to the most accurate one when applied to the surface of the copper foil. When the resin solid content is less than 30% by weight, the viscosity is too low and it flows immediately after application to the copper foil surface, making it difficult to ensure film thickness uniformity. On the other hand, when the resin solid content exceeds 70% by weight, the viscosity increases and it becomes difficult to form a thin film on the surface of the copper foil.

  When the resin varnish is used to form a semi-cured resin layer, the measured resin flow is preferably in the range of 0% to 10%. When the resin flow is high, the thickness of the insulating layer formed using the resin layer of the resin-coated copper foil becomes nonuniform. However, the resin varnish according to the present invention can suppress the resin flow to a low value of 10% or less. In addition, since the resin varnish which concerns on this invention can implement | achieve the level which resin flow hardly produces, the lower limit of the said resin flow was made into 0%. In addition, the more preferable range of the resin flow of the resin varnish concerning this invention is 0%-5%.

  In this specification, the resin flow is based on MIL-P-13949G in the MIL standard. Four 10 cm square samples are sampled from a resin-coated copper foil with a resin thickness of 55 μm. It is a value calculated based on Equation 1 from the result of measuring the resin outflow weight at the time of laminating under the conditions of a press temperature of 171 ° C., a press pressure of 14 kgf / cm 2, and a press time of 10 minutes in a stacked state (laminate).

The resin layer is soluble in a solvent and contains 2 to 50 parts by weight of a polymer component having one or more of hydroxyl group, carboxyl group and amino group in the molecule as a functional group, and a boiling point of 200 ° C. or more. You may contain 50 weight part or more of the epoxy resin compound which consists of an epoxy resin and an amine epoxy resin hardening | curing agent with a boiling point of 200 degreeC or more. The resin layer may be a fluororesin substrate or a fluororesin film adhesive resin. The polymer component may be a mixture of one or more selected from the group of polyvinyl acetal resins, phenoxy resins, aromatic polyamide resins, polyether sulfone resins, and polyamideimide resins. The epoxy resin having a boiling point of 200 ° C. or higher is a mixture of one or more selected from the group of bisphenol A type epoxy resin, bisphenol F type epoxy resin, rubber-modified bisphenol A type epoxy resin, and biphenyl type epoxy resin. There may be.
The amine-based epoxy resin curing agent is an aromatic polyamine, a polyamide, and one or more selected from the group of amine adducts obtained by polymerizing or condensing these with an epoxy resin or a polyvalent carboxylic acid. May be.

  The fluororesin substrate or fluororesin film refers to PTFE (polytetrafluoroethylene (tetrafluoroethylene)), PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer), FEP (tetrafluoroethylene / hexafluoro). Propylene copolymer (4.6 fluoride)), ETFE (tetrafluoroethylene / ethylene copolymer), PVDF (polyvinylidene fluoride (difluoride)), PCTFE (polychlorotrifluoroethylene (trifluoride)) ), A base material or a film using a fluororesin composed of at least one thermoplastic resin selected from polyallylsulfone, aromatic polysulfide, and aromatic polyether and a fluororesin. . It does not matter whether or not a skeletal material such as glass cloth is included. Moreover, there is no special limitation also about the thickness of this fluororesin base material.

  Further, as the curing agent, for the purpose of merely curing, amines such as dicyandiamide, imidazoles and aromatic amines, phenols such as bisphenol A and brominated bisphenol A, phenol novolac resins and cresol novolacs Any curing agent such as novolaks such as resins and acid anhydrides such as phthalic anhydride can be used. These curing agents are particularly effective for epoxy resins. However, it is most preferable to use an amine epoxy resin curing agent having a boiling point of 200 ° C. or higher from the viewpoint of significantly improving the adhesion between the fluororesin substrate and the metal foil. If the press molding temperature is around 180 ° C. and the boiling point of the curing agent is near the press molding temperature, the epoxy resin curing agent will boil due to the press molding, and bubbles are likely to be generated in the cured insulating resin layer. The most stable adhesion can be obtained when an amine-based epoxy resin curing agent is used to form an adhesive layer between the fluororesin substrate and the metal foil. That is, the “amine epoxy resin curing agent having a boiling point of 200 ° C. or more” is selected from the group of aromatic polyamines, polyamides, and amine adducts obtained by polymerizing or condensing these with epoxy resins or polyvalent carboxylic acids. The case where one kind or two kinds or more are used. More specifically, 4,4′-diaminodiphenylenesulfone, 3,3′-diaminodiphenylenesulfone, 4,4-diaminodiphenylel, 2,2-bis [4- It is preferable to use either (4-aminophenoxy) phenyl] propane or bis [4- (4-aminophenoxy) phenyl] sulfone. Moreover, since the addition amount with respect to the epoxy resin of the said amine epoxy resin hardening | curing agent is derived from each equivalent naturally, it thinks that it is not necessary to specify the compounding ratio strictly strictly. Therefore, in this invention, the addition amount of a hardening | curing agent is not specifically limited.

  It is also preferable to use a curing accelerator that is added in an appropriate amount as required. The curing accelerator referred to here is a tertiary amine, imidazole, urea curing accelerator or the like. In the present invention, the mixing ratio of the curing accelerator is not particularly limited. This is because the amount of the hardening accelerator can be arbitrarily determined by the manufacturer in consideration of heating conditions during press working.

  The resin layer preferably contains a rubbery resin. The rubber resin referred to here is described as a concept including natural rubber and synthetic rubber, and the latter synthetic rubber includes styrene-butadiene rubber, butadiene rubber, butyl rubber, ethylene-propylene rubber and the like. Furthermore, when heat resistance is required, it is also useful to selectively use heat-resistant synthetic rubbers such as nitrile rubber, chloroprene rubber, silicon rubber, urethane rubber. Regarding these rubber resins, it is desirable to have various functional groups at both ends so as to react with the polymer component to form a copolymer.

  Furthermore, it is also preferable to add the above-mentioned high-molecular polymer crosslinking agent as necessary. For example, when a polyvinyl acetal resin is used as the polymer, a urethane resin is used as a cross-linking material.

  The components of the resin composition of the resin layer are 50 parts by weight to 80 parts by weight of the epoxy resin, 1 part by weight to 15 parts by weight of the curing agent, and 0 part of the curing accelerator when the resin composition is 100 parts by weight. .01 parts by weight to 1.0 parts by weight, 2 to 50 parts by weight of the polymer component, 1 to 5 parts by weight of the crosslinking agent, and 1 to 10 parts by weight of the rubbery resin are employed. May be. As long as it is included in this composition range, good adhesion between the fluororesin substrate and the metal foil is maintained, and variation in product adhesion is reduced.

  The resin layer is 5 to 50 parts by weight of an epoxy resin (including a curing agent), 50 to 95 parts by weight of a polyethersulfone resin (having a hydroxyl group or an amino group at the terminal and being soluble in a solvent), and What was formed using the resin mixture which consists of a hardening accelerator added suitably as needed, or what made the said resin mixture semi-hardened may be used.

  The resin layer is a resin layer having a first thermosetting resin layer and a second thermosetting resin layer located on the surface of the first thermosetting resin layer in order from the copper foil side, The curable resin layer is formed of a resin component that does not dissolve in chemicals during desmear processing in the wiring board manufacturing process, and the second thermosetting resin layer dissolves in chemicals during desmear processing in the wiring board manufacturing process. Then, it may be formed using a resin that can be washed and removed. The first thermosetting resin layer may be formed using a resin component obtained by mixing one or more of polyimide resin, polyethersulfone, and polyphenylene oxide. The second thermosetting resin layer may be formed using an epoxy resin component. The thickness t1 (μm) of the first thermosetting resin layer is Rz (μm) of the roughened surface roughness of the copper foil with carrier, and the thickness of the second thermosetting resin layer is t2 (μm). Then, t1 is preferably a thickness that satisfies the condition of Rz <t1 <t2.

  The resin layer may be a prepreg in which a skeleton material is impregnated with a resin. The resin impregnated in the skeleton material is preferably a thermosetting resin. The prepreg may be a known prepreg or a prepreg used for manufacturing a printed wiring board. The prepreg may be a prepreg manufactured by a manufacturing method having the following steps. 1. A liquid resin film forming step of forming a liquid resin layer as a film having a predetermined thickness on a flat work plane using a liquid thermosetting resin. 2. A preliminary drying step in which the liquid resin layer on the work plane is dried as it is to obtain a dry resin layer. 3. A skeleton material pre-adhesion step in which a skeleton material is superimposed on the surface of the dry resin layer on the work plane, preheated and pressed to form a dry resin layer with a skeleton material. 4). A resin impregnation step in which the resin is heated at a temperature at which the resin can be reflowed while the dry resin layer with the skeleton material is placed on the work plane, and the skeleton material is impregnated with the thermosetting resin component. 5. When the resin impregnation is completed, the cooling step is performed so that the temperature setting operation is immediately performed without completely curing the thermosetting resin, and the semi-cured state of the thermosetting resin impregnated in the skeleton material is maintained to be in the prepreg state. .

The skeleton material may include aramid fibers, glass fibers, or wholly aromatic polyester fibers. The skeleton material is preferably an aramid fiber, a glass fiber, or a nonwoven fabric or woven fabric of wholly aromatic polyester fibers. The wholly aromatic polyester fiber is preferably a wholly aromatic polyester fiber having a melting point of 300 ° C. or higher. The wholly aromatic polyester fiber having a melting point of 300 ° C. or higher is a fiber produced using a resin called a so-called liquid crystal polymer, and the liquid crystal polymer contains 2-hydroxyl-6-naphthoic acid and p-hydroxybenzoic acid. The main component is an acid polymer. Since this wholly aromatic polyester fiber has a low dielectric constant and low dielectric loss tangent, it has excellent performance as a constituent material of an electrically insulating layer and can be used in the same manner as glass fiber and aramid fiber. is there.
In addition, in order to improve the wettability with the resin of the surface, it is preferable to perform the silane coupling agent process for the fiber which comprises the said nonwoven fabric and woven fabric. The silane coupling agent at this time may be an amino or epoxy silane coupling agent depending on the purpose of use.

  The prepreg is a prepreg obtained by impregnating a thermosetting resin into a nonwoven fabric using an aramid fiber or glass fiber having a nominal thickness of 70 μm or less, or a skeleton material made of glass cloth having a nominal thickness of 30 μm or less. Also good.

  These resins are, for example, methyl ethyl ketone (MEK), cyclopentanone, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, toluene, methanol, ethanol, propylene glycol monomethyl ether, dimethylformamide, dimethylacetamide, cyclohexanone, ethyl cellosolve, N-methyl. 2-Pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, etc., dissolved in a solvent to give a resin liquid, which is applied to the ultrathin copper layer, the heat-resistant layer, the rust-proof layer, or the chromate On the treatment layer or the silane coupling agent layer, for example, it is applied by a roll coater method or the like, and then heated and dried as necessary to remove the solvent to obtain a B stage state. For example, a hot air drying furnace may be used for drying, and the drying temperature may be 100 to 250 ° C, preferably 130 to 200 ° C. The resin layer composition may be dissolved using a solvent to obtain a resin liquid having a resin solid content of 3 wt% to 60 wt%, preferably 10 wt% to 40 wt%, more preferably 25 wt% to 40 wt%. In addition, it is most preferable at this stage from an environmental standpoint to dissolve using a mixed solvent of methyl ethyl ketone and cyclopentanone.

  The copper foil with a carrier provided with the resin layer (copper foil with a carrier with resin) is superposed on the base material, and the whole is thermocompression bonded to thermally cure the resin layer, and then the carrier is peeled off. Thus, the ultrathin copper layer is exposed (which is naturally the surface on the intermediate layer side of the ultrathin copper layer), and a predetermined wiring pattern is formed thereon.

  If this resin-attached copper foil with a carrier is used, the number of prepreg materials used when manufacturing a multilayer printed wiring board can be reduced. In addition, the copper-clad laminate can be manufactured even if the resin layer is made thick enough to ensure interlayer insulation or no prepreg material is used. At this time, the surface smoothness can be further improved by undercoating the surface of the substrate with an insulating resin.

  In addition, when the prepreg material is not used, the material cost of the prepreg material is saved and the laminating process is simplified, which is economically advantageous. Moreover, the multilayer printed wiring board manufactured by the thickness of the prepreg material is used. The thickness is reduced, and there is an advantage that an extremely thin multilayer printed wiring board in which the thickness of one layer is 100 μm or less can be manufactured.

  The thickness of the resin layer is preferably 0.1 to 120 μm.

  When the thickness of the resin layer is less than 0.1 μm, the adhesive strength is reduced, and when the copper foil with a carrier with the resin is laminated on the base material provided with the inner layer material without interposing the prepreg material, the circuit of the inner layer material It may be difficult to ensure interlayer insulation between the two. The total resin layer thickness with the cured resin layer and the semi-cured resin layer is preferably 0.1 μm to 120 μm, and practically preferable is 35 μm to 120 μm. And in that case, as for each thickness, it is desirable that a cured resin layer is 5-20 micrometers, and a semi-hardened resin layer is 15-115 micrometers. If the total resin layer thickness exceeds 120 μm, it may be difficult to produce a thin multilayer printed wiring board. If the total resin layer thickness is less than 35 μm, it is easy to form a thin multilayer printed wiring board, but an insulating layer between inner layer circuits This is because the resin layer may become too thin and the insulation between the circuits of the inner layer tends to become unstable. Moreover, when the cured resin layer thickness is less than 5 μm, it may be necessary to consider the surface roughness of the roughened copper foil surface. Conversely, if the cured resin layer thickness exceeds 20 μm, the effect of the cured resin layer may not be particularly improved, and the total insulating layer thickness becomes thick. The cured resin layer may have a thickness of 3 μm to 30 μm. The semi-cured resin layer may have a thickness of 7 μm to 55 μm. The total thickness of the cured resin layer and the semi-cured resin layer may be 10 μm to 60 μm.

Moreover, when the copper foil with a carrier having a resin layer is used for producing an extremely thin multilayer printed wiring board, the thickness of the resin layer is 0.1 μm to 5 μm, more preferably 0.5 μm to 5 μm, More preferably, the thickness is 1 μm to 5 μm in order to reduce the thickness of the multilayer printed wiring board. When the thickness of the resin layer is 0.1 μm to 5 μm, a heat resistant layer and / or a rust preventive layer is formed on the ultrathin copper layer in order to improve the adhesion between the resin layer and the carrier-attached copper foil. After providing the chromate treatment layer and / or the silane coupling treatment layer, it is preferable to form a resin layer on the heat-resistant layer, rust prevention layer, chromate treatment layer or silane coupling treatment layer.
When the resin layer includes a dielectric, the thickness of the resin layer is preferably 0.1 to 50 μm, preferably 0.5 μm to 25 μm, and more preferably 1.0 μm to 15 μm. preferable. In addition, the thickness of the above-mentioned resin layer says the average value of the thickness measured by cross-sectional observation in arbitrary 10 points | pieces.

  On the other hand, if the thickness of the resin layer is thicker than 120 μm, it becomes difficult to form a resin layer having a desired thickness in a single coating process, which is economically disadvantageous because of extra material costs and man-hours. Furthermore, since the formed resin layer is inferior in flexibility, cracks are likely to occur during handling, and excessive resin flow occurs during thermocompression bonding with the inner layer material, making smooth lamination difficult. There is.

  Furthermore, as another product form of this copper foil with a carrier with a resin, on the ultra-thin copper layer, or on the heat-resistant layer, rust-preventing layer, chromate-treated layer, or silane coupling-treated layer After coating with a resin layer and making it into a semi-cured state, the carrier can then be peeled off and manufactured in the form of a copper foil with resin without the carrier.

  Below, some examples of the manufacturing process of the printed wiring board using the copper foil with a carrier which concerns on this invention are shown.

  In one embodiment of a method for producing a printed wiring board according to the present invention, a step of preparing a copper foil with a carrier and an insulating substrate according to the present invention, a step of laminating the copper foil with a carrier and an insulating substrate, and with the carrier After laminating the copper foil and the insulating substrate so that the ultrathin copper layer side faces the insulating substrate, a copper-clad laminate is formed through a step of peeling the carrier of the copper foil with carrier, and then a semi-additive method, a modified semi-conductor A step of forming a circuit by any one of an additive method, a partial additive method, and a subtractive method. It is also possible for the insulating substrate to contain an inner layer circuit.

  In the present invention, the semi-additive method refers to a method in which a thin electroless plating is performed on an insulating substrate or a copper foil seed layer, a pattern is formed, and then a conductive pattern is formed using electroplating and etching.

Therefore, in one embodiment of a method for producing a printed wiring board according to the present invention using a semi-additive method, a step of preparing a copper foil with a carrier and an insulating substrate according to the present invention,
Laminating the copper foil with carrier and an insulating substrate;
A step of peeling the carrier of the copper foil with carrier after laminating the copper foil with carrier and the insulating substrate;
Removing all of the ultrathin copper layer exposed by peeling the carrier by a method such as etching or plasma using a corrosive solution such as acid
Providing a through hole or / and a blind via in the resin exposed by removing the ultrathin copper layer by etching;
Performing a desmear process on the region including the through hole or / and the blind via,
Providing an electroless plating layer for the region including the resin and the through hole or / and the blind via;
Providing a plating resist on the electroless plating layer;
Exposing the plating resist, and then removing the plating resist in a region where a circuit is formed;
Providing an electrolytic plating layer in a region where the circuit from which the plating resist has been removed is formed;
Removing the plating resist;
Removing the electroless plating layer in a region other than the region where the circuit is formed by flash etching or the like;
including.

In another embodiment of the method for producing a printed wiring board according to the present invention using a semi-additive method, a step of preparing a copper foil with a carrier and an insulating substrate according to the present invention,
Laminating the copper foil with carrier and an insulating substrate;
A step of peeling the carrier of the copper foil with carrier after laminating the copper foil with carrier and the insulating substrate;
Removing all of the ultrathin copper layer exposed by peeling the carrier by a method such as etching or plasma using a corrosive solution such as acid
Providing an electroless plating layer on the surface of the resin exposed by removing the ultrathin copper layer by etching;
Providing a plating resist on the electroless plating layer;
Exposing the plating resist, and then removing the plating resist in a region where a circuit is formed;
Providing an electrolytic plating layer in a region where the circuit from which the plating resist has been removed is formed;
Removing the plating resist;
Removing the electroless plating layer and the ultrathin copper layer in a region other than the region where the circuit is formed by flash etching or the like;
including.

  In the present invention, the modified semi-additive method is a method in which a metal foil is laminated on an insulating layer, a non-circuit forming portion is protected by a plating resist, and the copper is thickened in the circuit forming portion by electrolytic plating, and then the resist is removed. Then, a method of forming a circuit on the insulating layer by removing the metal foil other than the circuit forming portion by (flash) etching is indicated.

Therefore, in one embodiment of the method for producing a printed wiring board according to the present invention using the modified semi-additive method, the step of preparing the copper foil with carrier and the insulating substrate according to the present invention,
Laminating the copper foil with carrier and an insulating substrate;
A step of peeling the carrier of the copper foil with carrier after laminating the copper foil with carrier and the insulating substrate;
Providing a through hole or / and a blind via on the insulating substrate and the ultrathin copper layer exposed by peeling the carrier;
Performing a desmear process on the region including the through hole or / and the blind via,
Providing an electroless plating layer for the region including the through hole or / and the blind via;
Providing a plating resist on the surface of the ultrathin copper layer exposed by peeling the carrier,
Forming a circuit by electrolytic plating after providing the plating resist;
Removing the plating resist;
Removing the ultra-thin copper layer exposed by removing the plating resist by flash etching;
including.

In another embodiment of the method for producing a printed wiring board according to the present invention using the modified semi-additive method, the step of preparing the copper foil with carrier and the insulating substrate according to the present invention,
Laminating the copper foil with carrier and an insulating substrate;
A step of peeling the carrier of the copper foil with carrier after laminating the copper foil with carrier and the insulating substrate;
Providing a plating resist on the exposed ultrathin copper layer by peeling off the carrier;
Exposing the plating resist, and then removing the plating resist in a region where a circuit is formed;
Providing an electrolytic plating layer in a region where the circuit from which the plating resist has been removed is formed;
Removing the plating resist;
Removing the electroless plating layer and the ultrathin copper layer in a region other than the region where the circuit is formed by flash etching or the like;
including.

  In the present invention, the partial additive method means that a catalyst circuit is formed on a substrate provided with a conductor layer, and if necessary, a substrate provided with holes for through holes or via holes, and etched to form a conductor circuit. Then, after providing a solder resist or a plating resist as necessary, it refers to a method of manufacturing a printed wiring board by thickening through holes, via holes, etc. on the conductor circuit by electroless plating.

Therefore, in one embodiment of the method for producing a printed wiring board according to the present invention using a partly additive method, a step of preparing the copper foil with carrier and the insulating substrate according to the present invention,
Laminating the copper foil with carrier and an insulating substrate;
A step of peeling the carrier of the copper foil with carrier after laminating the copper foil with carrier and the insulating substrate;
Providing a through hole or / and a blind via on the insulating substrate and the ultrathin copper layer exposed by peeling the carrier;
Performing a desmear process on the region including the through hole or / and the blind via,
Applying catalyst nuclei to the region containing the through-holes and / or blind vias;
Providing an etching resist on the surface of the ultrathin copper layer exposed by peeling the carrier,
Exposing the etching resist to form a circuit pattern;
Removing the ultrathin copper layer and the catalyst nucleus by a method such as etching or plasma using a corrosive solution such as an acid to form a circuit;
Removing the etching resist;
A step of providing a solder resist or a plating resist on the surface of the insulating substrate exposed by removing the ultrathin copper layer and the catalyst core by a method such as etching or plasma using a corrosive solution such as an acid;
Providing an electroless plating layer in a region where the solder resist or plating resist is not provided,
including.

  In the present invention, the subtractive method refers to a method of forming a conductor pattern by selectively removing unnecessary portions of a copper foil on a copper clad laminate by etching or the like.

Therefore, in one embodiment of the method for producing a printed wiring board according to the present invention using a subtractive method, a step of preparing the carrier-attached copper foil and the insulating substrate according to the present invention,
Laminating the copper foil with carrier and an insulating substrate;
A step of peeling the carrier of the copper foil with carrier after laminating the copper foil with carrier and the insulating substrate;
Providing a through hole or / and a blind via on the insulating substrate and the ultrathin copper layer exposed by peeling the carrier;
Performing a desmear process on the region including the through hole or / and the blind via,
Providing an electroless plating layer for the region including the through hole or / and the blind via;
Providing an electroplating layer on the surface of the electroless plating layer;
A step of providing an etching resist on the surface of the electrolytic plating layer or / and the ultrathin copper layer;
Exposing the etching resist to form a circuit pattern;
Removing the ultrathin copper layer and the electroless plating layer and the electrolytic plating layer by a method such as etching or plasma using a corrosive solution such as an acid to form a circuit;
Removing the etching resist;
including.

In another embodiment of the method for producing a printed wiring board according to the present invention using a subtractive method, a step of preparing the carrier-attached copper foil and the insulating substrate according to the present invention,
Laminating the copper foil with carrier and an insulating substrate;
A step of peeling the carrier of the copper foil with carrier after laminating the copper foil with carrier and the insulating substrate;
Providing a through hole or / and a blind via on the insulating substrate and the ultrathin copper layer exposed by peeling the carrier;
Performing a desmear process on the region including the through hole or / and the blind via,
Providing an electroless plating layer for the region including the through hole or / and the blind via;
Forming a mask on the surface of the electroless plating layer;
Providing an electroplating layer on the surface of the electroless plating layer on which no mask is formed;
A step of providing an etching resist on the surface of the electrolytic plating layer or / and the ultrathin copper layer;
Exposing the etching resist to form a circuit pattern;
Removing the ultra-thin copper layer and the electroless plating layer by a method such as etching or plasma using a corrosive solution such as an acid to form a circuit;
Removing the etching resist;
including.

  The process of providing a through hole or / and a blind via and the subsequent desmear process may not be performed.

Here, the specific example of the manufacturing method of the printed wiring board using the copper foil with a carrier of this invention is demonstrated in detail using drawing. Here, the carrier-attached copper foil having an ultrathin copper layer on which a roughened layer is formed will be described as an example. However, the present invention is not limited thereto, and the carrier has an ultrathin copper layer on which a roughened layer is not formed. The following method for producing a printed wiring board can be similarly performed using an attached copper foil.
First, as shown to FIG. 1-A, the copper foil with a carrier (1st layer) which has the ultra-thin copper layer in which the roughening process layer was formed on the surface is prepared.
Next, as shown in FIG. 1-B, a resist is applied onto the roughened layer of the ultrathin copper layer, exposed and developed, and etched into a predetermined shape.
Next, as shown in FIG. 1-C, after the plating for the circuit is formed, the resist is removed to form a circuit plating having a predetermined shape.
Next, as shown in FIG. 2-D, an embedding resin is provided on the ultrathin copper layer so as to cover the circuit plating (so that the circuit plating is buried), and then the resin layer is laminated, followed by another carrier. A copper foil (second layer) is bonded from the ultrathin copper layer side.
Next, as shown to FIG. 2-E, a carrier is peeled from the copper foil with a carrier of the 2nd layer.
Next, as shown in FIG. 2-F, laser drilling is performed at a predetermined position of the resin layer to expose the circuit plating and form a blind via.
Next, as shown in FIG. 3G, copper is embedded in the blind via to form a via fill.
Next, as shown in FIG. 3H, circuit plating is formed on the via fill as shown in FIGS. 1-B and 1-C.
Next, as shown to FIG. 3-I, a carrier is peeled from the copper foil with a carrier of the 1st layer.
Next, as shown in FIG. 4J, the ultrathin copper layers on both surfaces are removed by flash etching, and the surface of the circuit plating in the resin layer is exposed.
Next, as shown in FIG. 4K, bumps are formed on the circuit plating in the resin layer, and copper pillars are formed on the solder. Thus, the printed wiring board using the copper foil with a carrier of this invention is produced.

  As the another copper foil with a carrier (second layer), the copper foil with a carrier of the present invention may be used, a conventional copper foil with a carrier may be used, and a normal copper foil may be further used. Further, one or more circuits may be formed on the second layer circuit shown in FIG. 3H, and these circuits may be formed by a semi-additive method, a subtractive method, a partial additive method, or a modified semi-conductor method. You may carry out by any method of an additive method.

The copper foil with a carrier according to the present invention is preferably controlled so that the color difference on the surface of the ultrathin copper layer satisfies at least one of the following (1) to (4). In the present invention, the “color difference on the surface of the ultrathin copper layer” means the color difference on the surface of the ultrathin copper layer, or the color difference on the surface of the surface treatment layer when various surface treatments such as roughening treatment are applied. . That is, in the copper foil with a carrier according to the present invention, the color difference of the surface of the ultrathin copper layer, the roughening treatment layer, the heat resistance layer, the rust prevention layer, the chromate treatment layer, or the silane coupling layer is as follows (1) to (4): It is preferable to be controlled to satisfy any one or more.
(1) The color difference ΔL based on JISZ8730 of the surface of the ultrathin copper layer, the roughened layer, the heat-resistant layer, the rust-proof layer, the chromate-treated layer or the silane coupling-treated layer is −40 or less.
(2) The color difference ΔE * ab based on JISZ8730 on the surface of the ultrathin copper layer, the roughened layer, the heat resistant layer, the rust preventive layer, the chromate layer or the silane coupling layer is 45 or more.
(3) The color difference Δa based on JISZ8730 of the surface of the ultrathin copper layer, the roughened layer, the heat-resistant layer, the rust-proof layer, the chromate-treated layer or the silane coupling-treated layer is 20 or less.
(4) The color difference Δb based on JISZ8730 of the surface of the ultrathin copper layer, the roughened layer, the heat resistant layer, the rust preventive layer, the chromate layer or the silane coupling layer is 20 or less.

Here, the above-described color differences ΔL, Δa, and Δb are measured by a color difference meter, black / white / red / green / yellow / blue are added, and the L * a * b color system based on JIS Z8730 is used. It is a comprehensive index shown, and is expressed as ΔL: black and white, Δa: reddish green, Δb: yellow blue. ΔE * ab is expressed by the following formula using these color differences.

The above-described color difference can be adjusted by increasing the current density when forming the ultrathin copper layer, decreasing the copper concentration in the plating solution, and increasing the linear flow rate of the plating solution.
Moreover, the above-mentioned color difference can also be adjusted by performing a roughening process on the surface of an ultra-thin copper layer and providing a roughening process layer. In the case of providing the roughened layer, the current density is higher than that of the prior art (for example, 40 to 60 A) using an electrolysis solution containing one or more elements selected from the group consisting of copper and nickel, cobalt, tungsten, and molybdenum. / Dm2), and can be adjusted by shortening the processing time (for example, 0.1 to 1.3 seconds). When a roughening layer is not provided on the surface of the ultrathin copper layer, use a plating bath in which the concentration of Ni is twice or more that of other elements, and use an ultrathin copper layer, heat resistant layer, rust preventive layer or chromate. Ni alloy plating (for example, Ni-W alloy plating, Ni-Co-P alloy plating, Ni-Zn alloy plating) is applied to the surface of the treatment layer or the silane coupling treatment layer at a lower current density (0.1 to 1.. 3A / dm ² ), and the processing time can be set long (20 to 40 seconds).

  When the color difference ΔL based on JISZ8730 on the surface of the ultrathin copper layer is −40 or less, for example, when forming a circuit on the surface of the ultrathin copper layer of the copper foil with carrier, the contrast between the ultrathin copper layer and the circuit is clear. As a result, the visibility is improved and the circuit can be aligned with high accuracy. The color difference ΔL based on JISZ8730 on the surface of the ultrathin copper layer is preferably −45 or less, more preferably −50 or less.

  When the color difference ΔE * ab based on JISZ8730 on the surface of the ultrathin copper layer is 45 or more, for example, when forming a circuit on the surface of the ultrathin copper layer of the copper foil with carrier, the contrast between the ultrathin copper layer and the circuit is As a result, the visibility is improved and the circuit can be accurately aligned. The color difference ΔE * ab based on JISZ8730 on the surface of the ultrathin copper layer is preferably 50 or more, more preferably 55 or more, and even more preferably 60 or more.

  When the color difference Δa based on JISZ8730 on the surface of the ultrathin copper layer is 20 or less, for example, when forming a circuit on the surface of the ultrathin copper layer of the copper foil with carrier, the contrast between the ultrathin copper layer and the circuit becomes clear. As a result, the visibility becomes better and the circuit alignment can be performed with high accuracy. The color difference Δa based on JISZ8730 on the surface of the ultrathin copper layer is preferably 15 or less, more preferably 10 or less, and even more preferably 8 or less.

  When the color difference Δb based on JISZ8730 on the surface of the ultrathin copper layer is 20 or less, for example, when forming a circuit on the surface of the ultrathin copper layer of the copper foil with carrier, the contrast between the ultrathin copper layer and the circuit becomes clear. As a result, the visibility becomes better and the circuit alignment can be performed with high accuracy. The color difference Δb based on JISZ8730 on the surface of the ultrathin copper layer is preferably 15 or less, more preferably 10 or less, and even more preferably 8 or less.

  When the color difference on the surface of the ultra-thin copper layer, roughened layer, heat-resistant layer, rust-proof layer, chromate-treated layer or silane coupling layer is controlled as described above, the contrast with the circuit plating becomes clear. , Visibility becomes good. Therefore, in the manufacturing process of the printed wiring board as described above, for example, as shown in FIG. 1-C, the circuit plating can be accurately formed at a predetermined position. In addition, according to the method for manufacturing a printed wiring board as described above, circuit plating is embedded in a resin layer, and thus, for example, removal of an ultrathin copper layer by flash etching as shown in FIG. At this time, the circuit plating is protected by the resin layer and the shape thereof is maintained, thereby facilitating the formation of a fine circuit. Further, since the circuit plating is protected by the resin layer, the migration resistance is improved, and the continuity of the circuit wiring is satisfactorily suppressed. For this reason, formation of a fine circuit becomes easy. Also, as shown in FIGS. 4-J and 4-K, when the ultra-thin copper layer is removed by flash etching, the exposed surface of the circuit plating has a shape recessed from the resin layer, so that bumps are formed on the circuit plating. In addition, copper pillars can be easily formed thereon, and the production efficiency is improved.

  A known resin or prepreg can be used as the embedding resin (resin). For example, a prepreg that is a glass cloth impregnated with BT (bismaleimide triazine) resin or BT resin, an ABF film or ABF manufactured by Ajinomoto Fine Techno Co., Ltd. can be used. The embedding resin may include a thermosetting resin or a thermoplastic resin. The embedding resin may include a thermoplastic resin. The type of the embedded resin is not particularly limited. For example, epoxy resin, polyimide resin, polyfunctional cyanate ester compound, maleimide compound, polyvinyl acetal resin, urethane resin, block copolymer polyimide resin, block copolymer Resin including polyimide resin, paper base phenolic resin, paper base epoxy resin, synthetic fiber cloth base epoxy resin, glass cloth / paper composite base epoxy resin, glass cloth / glass non-woven composite base epoxy resin and glass A cloth base epoxy resin, a polyester film, a polyimide film, a liquid crystal polymer film, a fluororesin film, etc. can be mentioned as a suitable thing.

  EXAMPLES The present invention will be described in more detail below with reference to examples of the present invention, but the present invention is not limited to these examples.

1. Production of Copper Foil with Carrier As a copper foil carrier, a long electrolytic copper foil having a thickness of 35 μm (JTC made by JX Nippon Mining & Metals) and a rolled copper foil having a thickness of 33 μm (C1100 made by JX Nippon Mining & Metals) Prepared. With respect to the shiny surface of this copper foil, the intermediate layer formation treatment described in Table 1 was performed in the following conditions in order on the carrier surface and the ultrathin copper layer side in a roll-to-roll type continuous line under the following conditions. . Washing and pickling were performed between the processing steps on the carrier surface side and the ultrathin copper layer side.

(Plating conditions)
・ Molybdenum-cobalt alloy plating Cobalt sulfate: 10-200 g / L
Sodium molybdate: 5 to 200 g / L
Trisodium citrate: 2 to 240 g / L
pH: 2-5
Liquid temperature: 10-70 degreeC

・ Molybdenum-nickel alloy plating Nickel sulfate: 10-200 g / L
Trisodium molybdate: 5 to 60 g / L
Sodium citrate: 2 to 120 g / L
pH: 4-7
Liquid temperature: 20-60 degreeC

・ Molybdenum-iron alloy plating Iron sulfate: 10-200 g / L
Sodium molybdate: 5 to 100 g / L
Trisodium citrate: 2 to 200 g / L
Boric acid: 1-50 g / L
pH: 2-6
Liquid temperature: 10-70 degreeC

・ Ni plating Nickel sulfate: 250-500 g / L
Nickel chloride: 35 to 45 g / L
Nickel acetate: 10-20g / L
Trisodium citrate: 5-30 g / L
Brightener: Saccharin, butynediol, etc. Sodium dodecyl sulfate: 30-100 ppm
pH: 4-6
Bath temperature: 50-70 ° C
Current density: 3-15 A / dm ²

Subsequently, on a continuous roll-to-roll type plating line, an ultrathin copper layer having a thickness of 2 to 5 μm was formed on the intermediate layer by electroplating under the following conditions to produce a copper foil with a carrier. .
-Ultrathin copper layer (other than Example 3)
Copper concentration: 90-120 g / L
H ₂ SO ₄ concentration: 20 to 120 g / L
Electrolyte temperature: 20-80 ° C
Current density: 10 to 70 A / dm ²
Plating solution flow velocity: 1.0 m / s
-Ultrathin copper layer (Example 3)
Copper concentration: 60-90 g / L
H ₂ SO ₄ concentration: 20 to 120 g / L
Electrolyte temperature: 20-80 ° C
Current density: 80 A / dm ²
Plating liquid line flow rate: 4.0 m / s

  In Examples 1, 5, and 7, the surface of the ultrathin copper layer was subjected to the following roughening treatment, rust prevention treatment, chromate treatment, and silane coupling treatment in this order. In Example 4, the surface of the ultrathin copper layer was subjected to the following antirust treatment, chromate treatment, and silane coupling treatment in this order.

・ Roughening Cu: 10 to 20 g / L
Cu: 10 to 20 g / L
Co: 5 to 15 g / L
Ni: 5 to 15 g / L
pH: 1-4
Temperature: 40-50 ° C
Current density Dk: Example 1: 40 A / dm ² Example 5: 50 A / dm ² Example 7: 47 A / dm ²
Time: Example 1: 0.5 seconds, Example 5: 0.8 seconds, Example 7: 0.8 seconds Cu adhesion amount: 15 to 40 mg / dm ²
Co adhesion amount: 100 to 3000 μg / dm ²
Ni adhesion amount: 100 to 1000 μg / dm ²

・ Rust prevention treatment (Examples 1, 5, and 7)
Zn: 0 to 20 g / L
Ni: 0 to 5 g / L
pH: 3.5
Temperature: 40 ° C
Current density Dk: 0 to 1.7 A / dm ²
Time: 1 second Zn deposition amount: 5-250 μg / dm ²
Ni adhesion amount: 5 to 300 μg / dm ²
・ Rust prevention treatment (Example 4)
Zn: 10 g / L
Ni: 35 g / L
pH: 3.5
Temperature: 40 ° C
Current density Dk: 0.5 A / dm ²
Time: 46 seconds Zn deposition amount: 150-1500 μg / dm ²
Ni adhesion amount: 300-2600 μg / dm ²

・ Chromate treatment K ₂ Cr ₂ O ₇
(Na ₂ Cr ₂ O ₇ or CrO ₃ ): 2 to 10 g / L
NaOH or KOH: 10-50 g / L
ZnO or ZnSO ₄ 7H ₂ O: 0.05 to 10 g / L
pH: 7-13
Bath temperature: 20-80 ° C
Current density 0.05-5A / dm ²
Time: 5 to 30 seconds Cr adhesion amount: 10 to 150 μg / dm ²

・ Silane coupling treatment Vinyltriethoxysilane aqueous solution (vinyltriethoxysilane concentration: 0.1 to 1.4 wt%)
pH: 4-5
Time: 5-30 seconds

2. Various evaluations of copper foil with carrier Various evaluations were carried out by the following methods for the copper foil with carrier obtained as described above. The results are shown in Tables 1 and 2.

<Measurement of metal adhesion amount of intermediate layer>
The amount of nickel deposited was measured by ICP emission analysis after dissolving the sample in nitric acid with a concentration of 20% by mass. The amount of molybdenum, cobalt and iron deposited was determined by atomic absorption spectrometry after dissolving the sample in hydrochloric acid with a concentration of 7% by mass. It was measured by performing an analysis. In addition, the measurement of the adhesion amount of the said nickel, molybdenum, cobalt, and iron was performed as follows. First, after peeling off the ultrathin copper layer from the copper foil with carrier, only the vicinity of the surface on the intermediate layer side of the ultrathin copper layer is dissolved (if the thickness of the ultrathin copper layer is 1.4 μm or more, If the thickness of the ultrathin copper layer is less than 1.4 μm, only 0.5 μm thickness is dissolved from the surface of the thin copper layer on the intermediate layer side. Only 20% is dissolved.), The adhesion amount of the surface of the ultrathin copper layer on the intermediate layer side is measured. Further, after peeling off the ultrathin copper layer, only the vicinity of the surface on the intermediate layer side of the carrier is dissolved (only the thickness of 0.5 μm from the surface is dissolved), and the amount of adhesion on the surface of the carrier on the intermediate layer side is measured. And the value which totaled the adhesion amount of the surface by the side of the intermediate | middle layer of an ultra-thin copper layer and the adhesion amount of the surface by the side of the intermediate | middle layer of a carrier was made into the metal adhesion amount of an intermediate | middle layer.

<XPS analysis>
<Evaluation by STEM>
The measurement conditions when the element distribution in the cross section of the copper foil with a carrier is observed by STEM are shown below.
・ Device: STEM (Hitachi, Ltd., model HD-2000 STEM)
・ Acceleration voltage: 200kV
・ Magnification: 100,000 to 1,000,000 times ・ Viewing field: 1500 nm × 1500 nm to 160 nm × 160 nm
Elemental concentration line analysis was performed for 50 to 1000 nm in length through the carrier / intermediate layer / ultra thin copper layer. Carbon was excluded from the detected elements, and the concentration (% by mass) of each element was analyzed.
STEM evaluation is also applied to the case after bonding the ultrathin copper layer side of the copper foil with a carrier on the insulating substrate and performing pressure bonding in the atmosphere at 20 kgf / cm ² and 220 ° C. × 2 hours. went.

<Pinhole>
The number of pinholes was visually measured using a consumer photographic backlight as a light source. The number of pinholes is determined by bonding the ultrathin copper layer side of the copper foil with carrier on the insulating substrate and performing pressure bonding under the conditions of 20 kgf / cm ² and 220 ° C. × 2 hours in the atmosphere. It peeled and measured by making a backlight permeate | transmit from the insulating substrate side.

<Peel strength>
After bonding the ultra-thin copper layer side of the copper foil with carrier on the insulating substrate and performing pressure bonding under the conditions of 20 kgf / cm ² and 220 ° C. × 2 hours in the atmosphere, the peel strength is measured with a load cell. The foil carrier side was pulled and measured according to the 90 ° peeling method (JIS C 6471 8.1). Further, the peel strength of the carrier-attached copper foil before being bonded onto the insulating substrate was also measured.

<Float 220 ° C>
The copper foil with a carrier was heated in an atmospheric heating furnace at 220 ° C. for 4 hours. After heating, the number of blisters per dm ² was counted with an optical microscope.

<Fukure 400 ° C>
The copper foil with carrier was heated in an atmospheric heating furnace at 400 ° C. for 10 minutes. After heating, the number of blisters per dm ² was counted with an optical microscope.

<Measurement of surface color difference>
Using a color difference meter MiniScan XE Plus manufactured by HunterLab, the surface of the ultra-thin copper layer of the copper foil with carrier according to the example according to JISZ8730 (rust prevention treatment, chromate treatment, silane coupling) When processing was performed, color differences ΔL, Δa, Δb, ΔE * ab from white (after the last processing) were measured. In the above color difference meter, the measured value of the white plate is ΔE * ab = 0, and the measured value when measured in the dark with a black bag covered is ΔE * ab = 90, and the color difference is calibrated. Among these, ΔE * ab was measured using the L * a * b color system, ΔL: black and white, Δa: reddish green, Δb: yellow blue based on the following formula. Where the color difference ΔE * ab is defined as zero for white and 90 for black;
Note that the color differences ΔL, Δa, Δb, ΔE * ab based on JIS Z8730 in a micro area such as a copper circuit surface are, for example, a micro surface spectral color difference meter (model: VSS400, etc.) manufactured by Nippon Denshoku Industries Co., Ltd. Measurement can be performed using a known measuring device such as a company-made micro-surface spectrocolorimeter (model: SC-50μ or the like).

<Evaluation of visibility>
After applying a plating resist on the ultrathin copper layer of the copper foil with a carrier according to the example, electrolytic plating was performed to form a 20 μm × 20 μm square copper plating portion. Then, after removing the plating resist, an attempt was made to detect the copper plating portion with a CCD camera. If it can be detected 10 times out of 10, it will be “◎◎”, if it can be detected more than 9 times in 10 times, “◎”, if it can be detected 7-8 times, “○”, it can be detected 6 times. In this case, “Δ” is indicated, and “x” is indicated when it is detected five times or less.

(Evaluation results)
In each of Examples 1 to 7, pinholes were well suppressed, and even better peel strength was exhibited.
In Comparative Examples 1 and 2, the intermediate layer was not formed, and the carrier could not be peeled from the ultrathin copper layer before and after thermocompression bonding.
In Comparative Example 3, since no molybdenum was present in the intermediate layer, the carrier could not be peeled off from the ultrathin copper layer after thermocompression bonding, and blistering occurred frequently.
In Comparative Example 4, since the amount of nickel deposited on the intermediate layer was small and molybdenum was not present in the intermediate layer, the carrier could not be peeled from the ultrathin copper layer before and after thermocompression bonding.
In Comparative Example 5, since the amount of molybdenum attached to the intermediate layer was large, pinholes in the ultrathin copper layer increased, and the peel strength was too low.
In Comparative Example 6, since the adhesion amount of molybdenum in the intermediate layer was small, the carrier could not be peeled off from the ultrathin copper layer after thermocompression bonding, and blistering occurred frequently.
In Comparative Example 7, since the amount of cobalt deposited on the intermediate layer was small, the carrier could not be peeled from the ultrathin copper layer after thermocompression bonding.
In Comparative Example 8, since the amount of nickel deposited in the intermediate layer was large, pinholes in the ultrathin copper layer increased, blistering occurred frequently, and the peel strength was too low.
In FIG. 5, the STEM line analysis result after the board | substrate bonding of Example 5 is shown. In FIG. 6, the STEM line analysis result after the board | substrate bonding of the comparative example 3 is shown.
In addition, about the Example and comparative example which were able to peel an ultra-thin copper layer from a carrier, all peeled between the intermediate | middle layer and the ultra-thin copper layer.

Claims (33)

A carrier-attached copper foil comprising a carrier, an intermediate layer laminated on the carrier, and an ultrathin copper layer laminated on the intermediate layer,
The intermediate layer is made of molybdenum-nickel alloy, molybdenum-cobalt alloy, or molybdenum-iron alloy,
When the intermediate layer contains molybdenum in an amount of 50 to 10,000 μg / dm ² , nickel is included in the intermediate layer in an amount of 50 to 40,000 μg / dm ² , and when the intermediate layer contains cobalt, the amount of cobalt is 50 10000 μg / dm ² , when the intermediate layer contains iron, the amount of iron adhered is 50 to 10000 μg / dm ² ,
From the cross section of the carrier / intermediate layer / ultra-thin copper layer, when carrying out 50-1000 nm long STEM line analysis in the range including all of them in this order, the maximum value of the molybdenum concentration is 1-70% by mass. Copper foil.   The maximum value of the molybdenum concentration is 3 to 70% by mass when 50 to 1000 nm long STEM line analysis is performed in a range including all of them in this order from the cross section of the carrier / intermediate layer / ultra thin copper layer. The copper foil with a carrier according to 1.   When a 50 to 1000 nm long STEM line analysis is performed in a range including all of them in this order from the cross section of the carrier / intermediate layer / ultra thin copper layer, the maximum value of the molybdenum concentration is 5 to 60% by mass. 2. Copper foil with carrier according to 2. The intermediate layer is formed by laminating nickel or a nickel alloy and a molybdenum-nickel alloy, a molybdenum-cobalt alloy, or a molybdenum-iron alloy in this order on the carrier,
From the cross section of the copper foil carrier / intermediate layer / ultra thin copper layer, when a 50 to 1000 nm long STEM line analysis is performed in a range including all of them in this order, the maximum value of the nickel concentration is 50 to 95% by mass. The copper foil with a carrier as described in any one of Claims 1-3. When the insulating substrate is thermocompression bonded to the ultrathin copper layer in the atmosphere under the conditions of pressure: 20 kgf / cm ² and 220 ° C. × 2 hours,
From the cross section of the copper foil carrier / intermediate layer / ultra thin copper layer, when a 50 to 1000 nm long STEM line analysis is performed in a range including all of them in this order, the maximum value of the molybdenum concentration is 1 to 60% by mass. The copper foil with a carrier as described in any one of Claims 1-4. When the insulating substrate is thermocompression bonded to the ultrathin copper layer in the atmosphere under the conditions of pressure: 20 kgf / cm ² and 220 ° C. × 2 hours,
From the cross section of the copper foil carrier / intermediate layer / ultra-thin copper layer, when a 50-1000 nm long STEM line analysis was performed in a range including all of them in this order, molybdenum and nickel and / or cobalt and / or iron The copper foil with a carrier according to any one of claims 1 to 5, wherein a minimum copper concentration in a portion where copper coexists is 10 to 65 mass%. The copper with a carrier according to any one of claims 1 to 6, wherein the number of blisters between the carrier and the ultrathin copper layer is 0 / dm ² when heated in the atmosphere at 220 ° C for 4 hours. Foil. With the carrier according to any one of claims 1 to 7, wherein the number of blisters between the carrier and the ultrathin copper is 10 pieces / dm ² or less when heated in the atmosphere at 400 ° C for 10 minutes. Copper foil.   The copper foil with a carrier according to any one of claims 1 to 8, wherein the carrier is formed of an electrolytic copper foil or a rolled copper foil.   The copper foil with a carrier as described in any one of Claims 1-9 which has a roughening process layer in the said ultra-thin copper layer surface.   The roughening treatment layer is a layer made of any single element selected from the group consisting of copper, nickel, cobalt, phosphorus, tungsten, arsenic, molybdenum, chromium, and zinc, or an alloy containing at least one kind. Item 11. A copper foil with a carrier according to Item 10.   The copper with a carrier according to claim 10 or 11, comprising at least one layer selected from the group consisting of a heat-resistant layer, a rust-preventing layer, a chromate-treated layer, and a silane coupling-treated layer on the surface of the roughened layer. Foil.   In the surface of the said ultra-thin copper layer, it has 1 or more types of layers selected from the group which consists of a heat-resistant layer, a rust prevention layer, a chromate treatment layer, and a silane coupling treatment layer. The copper foil with a carrier of description.   The copper foil with a carrier as described in any one of Claims 1-9 provided with a resin layer on the said ultra-thin copper layer.   The copper foil with a carrier as described in any one of Claims 10-12 provided with a resin layer on the said roughening process layer.   The copper foil with a carrier of Claim 12 or 13 provided with a resin layer on 1 or more types of layers selected from the group which consists of the said heat-resistant layer, an antirust layer, a chromate treatment layer, and a silane coupling treatment layer.   The copper foil with a carrier according to any one of claims 14 to 16, wherein the resin layer is an adhesive resin.   The copper foil with a carrier according to any one of claims 14 to 17, wherein the resin layer is a semi-cured resin.   The copper foil with a carrier according to any one of claims 14 to 18, wherein the resin layer includes a dielectric.   The copper foil with a carrier according to any one of claims 1 to 19, wherein a color difference ΔL based on JISZ8730 on the surface of the ultrathin copper layer is -40 or less.   The copper foil with a carrier according to any one of claims 1 to 20, wherein a color difference ΔE * ab based on JISZ8730 on the surface of the ultrathin copper layer is 45 or more.   The copper foil with a carrier according to any one of claims 1 to 21, wherein a color difference Δa based on JISZ8730 on the surface of the ultrathin copper layer is 20 or less.   The copper foil with a carrier according to any one of claims 1 to 22, wherein a color difference Δb based on JISZ8730 on the surface of the ultrathin copper layer is 20 or less.   Forming an intermediate layer on the carrier by forming a layer containing at least one of molybdenum-cobalt alloy, molybdenum-nickel alloy, and molybdenum-iron alloy by dry plating or electroplating; and the intermediate layer The manufacturing method of the copper foil with a carrier as described in any one of Claims 1-23 including the process of forming an ultra-thin copper layer on top by electrolytic plating.   A nickel plating layer or an alloy plating layer containing nickel is formed on the carrier by dry plating or electroplating, and then a layer containing any one or more of molybdenum-cobalt alloy, molybdenum-nickel alloy, and molybdenum-iron alloy is formed. The manufacturing method of the copper foil with a carrier of Claim 24 including the process of forming an intermediate | middle layer by forming, and the process of forming an ultra-thin copper layer by electrolytic plating on the said intermediate | middle layer.   The printed wiring board manufactured using the copper foil with a carrier as described in any one of Claims 1-23.   The printed circuit board manufactured using the copper foil with a carrier as described in any one of Claims 1-23.   The copper clad laminated board manufactured using the copper foil with a carrier as described in any one of Claims 1-23. A step of preparing the carrier-attached copper foil according to any one of claims 1 to 23 and an insulating substrate,
Laminating the copper foil with carrier and an insulating substrate;
After laminating the carrier-attached copper foil and the insulating substrate, a copper-clad laminate is formed through a step of peeling the carrier of the carrier-attached copper foil,
Then, the manufacturing method of a printed wiring board including the process of forming a circuit by any method of a semi-additive method, a subtractive method, a partly additive method, or a modified semi-additive method. The process of forming a circuit in the ultra-thin copper layer side surface of the copper foil with a carrier according to any one of claims 1 to 23,
Forming a resin layer on the ultrathin copper layer side surface of the carrier-attached copper foil so that the circuit is buried;
Forming a circuit on the resin layer;
Forming the circuit on the resin layer, and then peeling the carrier; and
After the carrier is peeled off, the printed wiring board includes a step of exposing the circuit embedded in the resin layer formed on the surface of the ultrathin copper layer by removing the ultrathin copper layer Method.   The step of forming a circuit on the resin layer includes attaching another carrier-attached copper foil on the resin layer from the ultrathin copper layer side, and using the carrier-attached copper foil attached to the resin layer to form the circuit. The method for producing a printed wiring board according to claim 30, which is a step of forming.   The method for producing a printed wiring board according to claim 29, wherein another copper foil with a carrier to be bonded onto the resin layer is the copper foil with a carrier according to any one of claims 1 to 23.   The process according to any one of claims 30 to 32, wherein the step of forming a circuit on the resin layer is performed by any one of a semi-additive method, a subtractive method, a partly additive method, and a modified semi-additive method. A method for manufacturing a wiring board.