JP5247929B1 - Copper foil with carrier, method for producing copper foil with carrier, printed wiring board and printed circuit board - Google Patents

Abstract

The adhesion between the carrier and the ultrathin copper layer is high before the lamination process to the insulating substrate, the adhesion is lowered after the lamination process, and can be easily peeled off at the interface between the carrier and the ultrathin copper layer. Provision of a copper foil with a carrier in which the generation of pinholes on the surface of the thin copper layer is suppressed.
In a copper foil with a carrier, an intermediate layer is formed by laminating nickel and molybdenum, cobalt, or a molybdenum-cobalt alloy in this order on a copper foil carrier, and the adhesion amount of nickel is 1000. ˜40000 μg / dm ² , molybdenum adhesion amount is 50 to 1000 μg / dm ² , or cobalt adhesion amount is 50 to 1000 μg / dm ² , and in this order from the cross section of copper foil carrier / intermediate layer / ultra thin copper layer In the range including all of these, the maximum value of nickel concentration is 50 to 95% by mass, and molybdenum or cobalt is present at the maximum value of 1 to 50% by mass on the ultrathin copper side from nickel.
[Selection] Figure 1

Description

  The present invention relates to a copper foil with a carrier, a method for producing a copper foil with a carrier, a printed wiring board, and a printed circuit board. More specifically, the present invention relates to a copper foil with a carrier used as a material for a printed wiring board for fine patterns, a method for producing the copper foil with a carrier, a printed wiring board, and a printed circuit 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. There is a demand for high frequency response, and in particular, when an IC chip is mounted on a printed wiring board, a fine pitch of L / S = 20/20 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 (lamination 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 for the release layer in order to stabilize the peelability in a high temperature use environment such as a hot press. ing.

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 copper foil with a carrier in which the generation of pinholes on the surface of the ultrathin copper layer is suppressed.

  In order to achieve the above object, the present inventor conducted extensive research and used copper foil as a carrier, formed an intermediate layer between the ultrathin copper layer and the carrier, and formed this intermediate layer on the copper foil carrier. It is extremely effective to be composed of nickel and molybdenum or cobalt or molybdenum-cobalt alloy in order, control the amount of nickel, molybdenum and cobalt deposited, and control the concentration of nickel, molybdenum and cobalt near the intermediate layer. I found out that

The present invention has been completed on the basis of the above knowledge, and in one aspect, includes a copper foil carrier, an intermediate layer laminated on the copper foil carrier, and an ultrathin copper layer laminated on the intermediate layer. A copper foil with a carrier, wherein the intermediate layer is formed by laminating nickel and molybdenum or cobalt or a molybdenum-cobalt alloy in this order on the copper foil carrier. the adhesion amount ^{1000~40000μg / dm 2, 50~1000μg / dm} 2 adhesion amount of molybdenum may include molybdenum, if it contains cobalt is deposited amount 50~1000μg / dm ² of cobalt, the copper foil From the cross section of the carrier / intermediate layer / ultra-thin copper layer, when a 50 to 1000 nm long STEM line analysis was performed in a range including all of them in this order, the nickel concentration The maximum value of is 50 to 95 wt%, and the ultra-thin copper side of the nickel, copper foil with carrier in which molybdenum or cobalt is present from 1 to 50% by weight at the maximum value.

In one embodiment of the copper foil with a carrier according to the present invention, when the insulating substrate is thermocompression bonded to the ultrathin copper layer under the conditions of pressure: 20 kgf / cm ² and 220 ° C. × 2 hours in the atmosphere, 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. In addition, molybdenum or cobalt is present at a maximum value of 1 to 50% by mass on the ultrathin copper side from nickel.

In another embodiment of the copper foil with a carrier according to the present invention, 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. In addition, from the cross section of the copper foil carrier / intermediate layer / ultra-thin copper layer, nickel, molybdenum and / or cobalt, and copper coexist when a 50 to 1000 nm long STEM line analysis is performed in a range including all of them. The copper concentration minimum value of the place to do becomes 10-65 mass%.

  In still another embodiment of the copper foil with a carrier according to the present invention, the concentration of cobalt in the molybdenum-cobalt alloy of the intermediate layer is 20 to 80% by mass.

  In still another embodiment of the copper foil with a carrier according to the present invention, the copper foil carrier is formed of an electrolytic copper foil or a rolled copper foil.

  In still another embodiment of the copper foil with a carrier according to the present invention, the surface of the ultrathin copper layer has a roughening treatment layer.

  In still another embodiment of the copper foil with a carrier according to the present invention, the roughening treatment layer is any one selected from the group consisting of copper, nickel, cobalt and zinc, or any one or more. It is a layer made of an alloy containing.

  In still another embodiment of the copper foil with a carrier according to the present invention, one or more types selected from the group consisting of a rust prevention layer, a chromate treatment layer and a silane coupling treatment layer on the surface of the roughening treatment layer. It has a layer of.

  In still another embodiment of the copper foil with a carrier according to the present invention, one or more selected from the group consisting of a rust prevention layer, a chromate treatment layer and a silane coupling treatment layer on the surface of the ultrathin copper layer. It has a layer of.

In another aspect of the present invention, a nickel layer is formed on a copper foil carrier by dry plating or wet plating, and a molybdenum layer, a cobalt layer, or a molybdenum-cobalt alloy layer is formed on the nickel layer. It is a manufacturing method of the copper foil with a carrier of this invention including the process of forming an intermediate | middle layer, and the process of forming an ultra-thin copper layer on the said intermediate | middle layer by electroplating.

  In one Embodiment of the manufacturing method of the copper foil with a carrier which concerns on this invention, the process of forming a roughening process layer on the said ultra-thin copper layer is further included.

  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.

  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 well suppressed.

6 is a cross-sectional concentration profile after pressure bonding of a substrate according to Example 5. It is a density | concentration profile of the cross section after the board | substrate crimping | compression-bonding which concerns on 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 configured by laminating nickel and molybdenum or cobalt or a molybdenum-cobalt alloy in this order on a copper foil carrier. Since the adhesive force between nickel and copper is higher than the adhesive force between molybdenum or cobalt and copper, when the ultrathin copper layer is peeled off, it peels at the interface between the ultrathin copper layer and molybdenum or cobalt. Further, the nickel of the intermediate layer is expected to have a barrier effect that prevents the copper component from diffusing from the carrier into 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.

  Of the intermediate layer, molybdenum or cobalt or molybdenum-cobalt alloy is thinly present at the interface of the ultrathin copper layer. It is preferable for obtaining the property that the ultrathin copper layer can be peeled off from the carrier after the laminating step. When molybdenum or cobalt or molybdenum-cobalt alloy is present at the boundary between the carrier and the ultrathin copper layer without providing a nickel layer, the peelability is hardly improved, and there is no molybdenum or cobalt or molybdenum-cobalt alloy and the nickel layer. When the ultrathin copper layer is directly laminated, the peel strength is too strong or too weak depending on the amount of nickel in the nickel layer, and an appropriate peel strength cannot be obtained.

  In addition, if molybdenum or cobalt or molybdenum-cobalt alloy is present at the boundary between the carrier and the nickel layer, the intermediate layer is also peeled off at the time of peeling of the ultrathin copper layer, that is, peeling occurs between the carrier and the intermediate layer. This is not preferable. Such a situation is not only when molybdenum, cobalt, or molybdenum-cobalt alloy is provided at the interface with the carrier, but also when molybdenum, cobalt, or molybdenum-cobalt alloy is provided at the interface with the ultrathin copper layer. Or it may occur when the amount of cobalt is too large. This is because copper and nickel are likely to be in solid solution, so if they are in contact with each other, the adhesive force increases due to mutual diffusion and it is difficult to peel off, while molybdenum or cobalt and copper are less likely to dissolve and mutual diffusion. This is considered to be because the adhesive strength is weak at the interface between molybdenum, cobalt, or a molybdenum-cobalt alloy and copper, and is easily peeled off. Further, when the amount of nickel in the intermediate layer is insufficient, there is only a small amount of molybdenum or cobalt between the carrier and the ultrathin copper layer, so that they are in close contact and difficult to peel off.

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

In the intermediate layer, 1000~40000μg / dm ² adhesion amount of nickel, 50~1000μg / dm ² adhesion amount of molybdenum may include molybdenum, the amount of deposition of cobalt may include cobalt is in 50~1000μg / dm ² is there. Although the amount of pinholes tends to increase as the amount of nickel 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, nickel coating weight is preferably set to 5000~20000μg / dm ^2, be 7500~15000μg / dm ² More preferred. If containing molybdenum, molybdenum deposition amount is preferably set to 80~600μg / dm ^2, and more preferably a 100-400 / dm ^2. If it contains cobalt, the cobalt coating weight is preferably set to 80~600μg / dm ^2, and more preferably a 100-400 / dm ^2. In the case where a layer containing molybdenum and cobalt is provided in the intermediate layer, the total adhesion amount of molybdenum and cobalt is preferably 50 to 1200 μg / dm ² . The coating weight of the total of molybdenum and cobalt is preferably set to 100-1000 / dm ^2, and more preferably a 150~700μg / dm ^2.

<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 on the chromium layer of the intermediate layer in order to reduce pinholes in the ultrathin copper layer. A copper pyrophosphate plating solution or the like can be used as the strike plating treatment solution. Thus, the carrier-attached copper foil subjected to the strike plating with the copper-phosphorus alloy has phosphorus on both the intermediate layer surface and the ultrathin copper layer surface. For this reason, when it peels between an intermediate | middle layer / ultra-thin copper layer, phosphorus is detected from the surface of an intermediate | middle layer and an ultra-thin copper layer. Moreover, since the plating layer formed by strike plating becomes thin, cross-sectional observation is performed with FIB, TEM, etc., and when the thickness of the copper phosphorous plating layer on the intermediate layer is 0.1 μm or less, it is strike plating Can be determined.

<4. Ultra-thin 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 the 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 single layer selected from the group consisting of copper, nickel, phosphorus, tungsten, arsenic, molybdenum, chromium, cobalt and zinc, or a layer made of 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 copper, nickel, cobalt, zinc alone or an alloy, and the surface 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 of copper, nickel, cobalt, 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-preventing layer, a chromate treatment layer, and a silane coupling treatment layer may be formed on the surface of the roughening treatment 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 2 layers or more and 3 layers or more.

<6. Copper foil with carrier>
Thus, the copper foil with a carrier provided with the copper foil carrier, the intermediate | middle layer formed on the copper foil carrier, and the ultra-thin copper layer laminated | stacked on the intermediate | middle layer is manufactured. 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. A carrier is peeled off after being bonded to an insulating substrate such as a base epoxy resin, a glass cloth / glass nonwoven fabric composite base epoxy resin and a glass cloth base epoxy resin, a polyester film, a polyimide film, etc. In the case of the carrier-attached copper foil according to the present invention, the peeled portion is mainly the interface between the intermediate layer and the ultrathin copper layer. Subsequently, the ultrathin copper layer adhered to the insulating substrate is etched into the intended conductor pattern, and finally a printed wiring board or printed circuit board can be manufactured. As a printed wiring board manufactured using the copper foil with a carrier of the present invention, those in known forms can be widely used. For example, a conductor pattern is printed on an insulating substrate in order to electrically connect each component. A substrate in which the wiring formed by the above is provided on an insulating substrate or the like based on circuit design. Moreover, as a printed circuit board manufactured using the copper foil with a carrier of this invention, the thing of a well-known form can be used widely, for example, it is comprised with the said printed wiring, the various components mounted in a board | substrate, etc. A substrate in which a circuit is provided on an insulating substrate or the like can be given.

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 molybdenum or cobalt is present at a maximum value of 1 to 50% by mass on the ultrathin copper side from nickel.
As described above, the copper foil with carrier of the present invention is obtained by performing elemental analysis on the cross section of the copper foil carrier / intermediate layer / ultra thin copper layer. Carrier copper / nickel layer / molybdenum or cobalt or molybdenum-cobalt alloy layer / ultra thin copper layer It has a structure. At this time, since nickel and copper are easy to dissolve, when they are in contact with each other, the adhesive force is increased due to mutual diffusion and it is difficult to peel off. On the other hand, molybdenum or cobalt and copper are difficult to dissolve and mutual diffusion is difficult. Since it does not easily occur, the adhesive force is weak at the interface between the molybdenum or cobalt or molybdenum-cobalt alloy layer and copper. By changing the concentration of nickel and molybdenum or cobalt, the peel strength can be controlled by controlling the copper concentration in the intermediate layer. In addition, if the molybdenum or cobalt or molybdenum-cobalt alloy layer is present at the boundary between the carrier and the nickel layer, the intermediate layer is also peeled off at the time of peeling of the ultrathin copper layer, that is, peeling is performed between the carrier and the intermediate layer. Since it will occur, it is not preferable. Such a situation is not only when a molybdenum or cobalt or molybdenum-cobalt alloy layer is provided at the interface with the carrier, but also when a molybdenum or cobalt or molybdenum-cobalt alloy layer is provided at the interface with the ultrathin copper layer. This can occur if the amount of molybdenum or cobalt is too high. This is thought to be because molybdenum or cobalt and copper are difficult to dissolve and interdiffusion hardly occurs, and the adhesive force is weak at the interface between the molybdenum or cobalt or molybdenum-cobalt alloy layer and copper, and is easily peeled off. It is done. Further, when the amount of nickel in the intermediate layer is insufficient, there is only a small amount of molybdenum or cobalt between the carrier and the ultrathin copper layer, so that they are in close contact and difficult to peel off.

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 ultrathin copper layer, when a 50 to 1000 nm long STEM line analysis is performed in a range including all of these in this order, the maximum value of the nickel concentration is 50 to 95% by mass, and the ultrathin copper side from nickel In addition, 1 to 50% by mass of molybdenum or cobalt may be present at the maximum value.
Thus, even in the copper foil with a carrier after thermocompression bonding, when elemental analysis is performed on the cross section of the copper foil carrier / intermediate layer / ultra thin copper layer, the copper foil carrier / nickel layer / molybdenum or cobalt or molybdenum-cobalt alloy layer / electrode It has a thin copper layer structure. At this time, the presence of molybdenum or cobalt or a molybdenum-cobalt alloy layer at the interface between the nickel layer and the ultrathin copper layer suppresses element diffusion between the nickel layer and the ultrathin copper layer during thermocompression bonding of the insulated substrate, and A rapid increase in peel strength due to pressure bonding can be prevented, and a stable peel strength can be maintained.

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 ultrathin copper layer, when a 50 to 1000 nm long STEM line analysis is performed in a range including all of these, the minimum copper concentration at a location where nickel, molybdenum and / or cobalt and copper coexist is 10 to 10. It may be 65% by mass.
According to such a configuration, when the copper foil with a carrier of the present invention is subjected to elemental analysis of the cross section of the copper foil carrier / intermediate layer / ultra thin copper layer after thermocompression bonding, copper exists in the intermediate layer in a certain amount or more. doing. For this reason, there exists an effect that the fall of the extreme peeling strength after thermocompression-bonding can be prevented.

In the copper foil with a carrier of the present invention, the concentration of cobalt in the molybdenum-cobalt alloy of the intermediate layer may be 20 to 80% by mass.
According to such a configuration, the presence of the cobalt of the intermediate layer in a certain amount or more has the effect of preventing excessive copper diffusion into the intermediate layer and preventing an extreme increase in peel strength. is there.

  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)
・ Ni plating Nickel sulfate: 250-500 g / L
Nickel chloride: 35 to 45 g / L
Nickel acetate: 10-20g / L
Trisodium citrate: 15-30 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

・ Cobalt plating Cobalt sulfate: 200-300 g / L
Boric acid: 20-50 g / L
pH: 2-5
Liquid temperature: 10-70 degreeC
Current density: 0.5 to 20 A / dm ²
・ Molybdenum-cobalt alloy plating Cobalt sulfate: 10-200 g / L
Sodium molybdate: 5 to 200 g / L
Sodium citrate: 2-240 g / L
pH: 2-5
Liquid temperature: 10-70 degreeC
Current density: 0.5 to 10 A / dm ²

(Sputtering conditions)
Since the molybdenum layer cannot be formed by electroplating, it was produced with a roll-to-roll type sputtering apparatus. In that case, the thin oxide film on the copper foil surface may be removed by an ion gun (LIS), and then the coating layer may be formed. The thicknesses of the Ni layer and the Mo layer were changed by adjusting the sputtering power.
・ Equipment: Roll-to-roll type sputtering equipment (Shinko Seiki Co., Ltd.)
・ Achieving vacuum: 1.0 × 10 ⁻⁵ Pa
・ Sputtering pressure: 0.25 Pa
・ Conveying speed: 15m / min
・ Ion gun power: 225W
・ Sputtering power: 200 to 3000 W
·target:
For Ni layer = Ni (purity 3N)
For Mo layer = Mo (purity 3N)
Film formation rate: About 0.2 μm of film was formed for each target for a fixed time, the thickness was measured with a three-dimensional measuring device, and the sputtering rate per unit time was calculated.

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 Copper concentration: 30-120 g / L
H ₂ SO ₄ concentration: 20 to 120 g / L
Electrolyte temperature: 20-80 ° C
Current density: 10 to 100 A / dm ²

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.
・ Roughening treatment Cu: 10 to 20 g / L
Co: 1-10 g / L
Ni: 1-10g / L
pH: 1-4
Temperature: 40-50 ° C
Current density Dk: 20 to 30 A / dm ²
Time: 1 to 5 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 Zn: 0-20g / 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
・ 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 Table 1.

<Measurement of adhesion amount>
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 and cobalt deposited was dissolved in hydrochloric acid with a concentration of 7% by mass and quantitative analysis was performed by atomic absorption spectrometry. Measured by doing.

<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.

(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, since nickel, cobalt, and molybdenum were not present, peeling was not possible before and after pressing.
In Comparative Example 3, since molybdenum and cobalt were not present, peeling was not possible after pressing.
In Comparative Example 4, molybdenum and cobalt were not present, and the amount of nickel deposited was small, so that peeling was not possible before and after pressing.
In Comparative Examples 5 and 7, since the amount of cobalt deposited was too large, pinholes occurred frequently and the peel strength was too low.
In Comparative Example 6, since the amount of molybdenum deposited was too large, pinholes occurred frequently and the peel strength was too low.
In Comparative Example 8, the concentration of molybdenum and cobalt measured by the STEM line analysis of the cross section was low, so that peeling became impossible after pressing.
In FIG. 1, the density | concentration profile of the cross section after the board | substrate crimping | compression-bonding which concerns on Example 5 is shown. In FIG. 2, the density | concentration profile of the cross section after the board | substrate crimping | compression-bonding which concerns on the comparative example 3 is shown.

Claims (13)

A copper foil with a carrier comprising a copper foil carrier, an intermediate layer laminated on the copper foil carrier, and an ultrathin copper layer laminated on the intermediate layer,
The intermediate layer is configured by laminating nickel and molybdenum or cobalt or a molybdenum-cobalt alloy in this order on the copper foil carrier.
Wherein in the intermediate layer, 1000~40000μg / dm ² adhesion amount of nickel, 50~1000μg / dm ² adhesion amount of molybdenum case containing molybdenum, 50~1000μg / dm ² adhesion amount of cobalt may include cobalt And
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. And the copper foil with a carrier in which 1-50 mass% of molybdenum or cobalt exists in the ultrathin copper side from nickel by the maximum value. 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 nickel concentration is 50 to 95% by mass. The copper foil with a carrier according to claim 1, wherein molybdenum or cobalt is present at a maximum value of 1 to 50% by mass on the ultrathin copper side from nickel. 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,
Locations where nickel, molybdenum and / or cobalt, and copper coexist when a 50 to 1000 nm long STEM line analysis is performed in a range including all of these from the cross section of the copper foil carrier / intermediate layer / ultra thin copper layer The copper foil with a carrier according to claim 1 or 2, wherein the minimum copper concentration is 10 to 65 mass%.   The copper foil with a carrier according to claim 1, wherein a concentration of cobalt in the molybdenum-cobalt alloy in the intermediate layer is 20 to 80% by mass.   The copper foil with a carrier according to any one of claims 1 to 4, wherein the copper foil carrier is formed of an electrolytic copper foil or a rolled copper foil.   The copper foil with a carrier in any one of Claims 1-5 which have a roughening process layer on the said ultra-thin copper layer surface.   The copper foil with a carrier according to claim 6, wherein the roughening layer is a layer made of any single substance selected from the group consisting of copper, nickel, cobalt, and zinc, or an alloy containing at least one of them.   The copper foil with a carrier of Claim 6 or 7 which has 1 or more types of layers selected from the group which consists of a rust prevention layer, a chromate processing layer, and a silane coupling processing layer on the surface of the said roughening process layer.   The copper with a carrier according to any one of claims 1 to 8, which has one or more layers selected from the group consisting of a rust preventive layer, a chromate treatment layer and a silane coupling treatment layer on the surface of the ultrathin copper layer. Foil. Forming a nickel layer on the copper foil carrier by dry plating or wet plating, and forming an intermediate layer by forming a molybdenum layer, a cobalt layer, or a molybdenum-cobalt alloy layer on the nickel layer; and The manufacturing method of copper foil with a carrier in any one of Claims 1-9 including the process of forming an ultra-thin copper layer by electroplating on an intermediate | middle layer.
  The manufacturing method of the copper foil with a carrier of Claim 10 including the process of forming a roughening process layer on the said ultra-thin copper layer.   The printed wiring board manufactured using the copper foil with a carrier in any one of Claims 1-9.   The printed circuit board manufactured using the copper foil with a carrier in any one of Claims 1-9.

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