JP5922227B2 - Copper foil with carrier, method for producing copper foil with carrier, and method for producing printed wiring board - Google Patents

Description

  The present invention relates to a copper foil with a carrier, a method for producing a copper foil with a carrier, and a printed wiring 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, and 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. 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 has been found that it is extremely effective to form a nickel layer and a chromate layer in order, to control the adhesion amount of nickel and chromium, and to control the nickel and chromium concentrations in the vicinity of the intermediate layer.

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. It is copper foil with a carrier, Comprising: The said intermediate | middle layer is comprised by laminating | stacking the nickel layer and the chromate layer in this order on the said copper foil carrier, The adhesion amount of the nickel of the said intermediate | middle layer is 100-40000 microgram / dm ² , the amount of chromium deposited is 5 to 100 μg / dm ² , and 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 has a maximum value of Ni concentration of 40 to 95% by mass and a minimum value of Cu concentration of 1 to 50% by mass of a portion where Ni and Cu coexist.

  In one embodiment of the copper foil with a carrier according to the present invention, 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, Cr The maximum concentration is 1 to 10% by mass, and the Cr peak coexists with or is in contact with the Ni peak.

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 under the conditions of pressure: 20 kgf / cm ² and 220 ° C. × 2 hours in the atmosphere. In addition, from the cross section of the copper foil carrier / intermediate layer / ultra-thin copper layer, when performing a 50-1000 nm long STEM line analysis in a range including all of these, the maximum value of Ni concentration is 30-95% by mass, And the minimum value of Cu density | concentration of the location where Ni and Cu coexist will be 5 to 65 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 plating is formed on a copper foil carrier, and then an intermediate layer is formed by forming a chromate layer by electrolytic chromate, and an extremely thin layer is formed by electrolytic plating on the intermediate layer. And a step of forming a copper layer.

  In one embodiment of the method for producing a copper foil with a carrier according to the present invention, strike plating is performed with a copper-phosphorus alloy on the chromate layer of the intermediate layer, and an ultrathin copper layer is formed thereon.

  The manufacturing method of the copper foil with a carrier which concerns on this invention in another one Embodiment includes the process of forming a roughening process layer on the said ultra-thin copper layer further.

  In still another aspect, the present invention is a printed wiring 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 satisfactorily suppressed.

It is a density | concentration profile of the cross section before the board | substrate crimping | compression-bonding which concerns on Example 9. FIG. It is a density | concentration profile of the cross section after the board | substrate crimping | compression-bonding which concerns on Example 9. FIG. 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 titanium or stainless steel drum, 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 a nickel layer and a chromate layer in this order on a copper foil carrier. Since the adhesive strength between nickel and copper is higher than the adhesive strength between chromium and copper, when the ultrathin copper layer is peeled off, it peels at the interface between the ultrathin copper layer and chromium. 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.

  Among the intermediate layers, the chromate layer is thin at the interface of the ultrathin copper layer, while the ultrathin copper layer does not peel from the carrier before the lamination process to the insulating substrate, while the carrier after the lamination process to the insulating substrate From the viewpoint of obtaining the property that the ultrathin copper layer can be peeled off. When the chromate layer is present at the boundary between the carrier and the ultrathin copper layer without providing the nickel layer, the peelability is hardly improved. In addition, when there is no chromate layer and a nickel layer and an ultrathin copper layer are 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.

  If the chromate layer is present at the boundary between the carrier and the nickel layer, the intermediate layer is also peeled off along with the peeling of the ultrathin copper layer, that is, peeling occurs between the carrier and the intermediate layer. Such a situation can occur not only when the chromate layer is provided at the interface with the carrier, but also when the amount of chromium is excessive even if the chromate layer is provided at the interface with the ultrathin copper layer. 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 is difficult to peel off, while chromium and copper are less likely to dissolve and cause mutual diffusion. It is considered that the adhesion between the chromium and copper interface is weak and easy to peel off. Further, when the nickel amount in the intermediate layer is insufficient, since only a very small amount of chromium exists between the carrier and the ultrathin copper layer, they are in close contact with each other and are difficult to peel off.

In the intermediate layer, the adhesion amount of nickel 100~40000μg / dm ^2, the amount of deposition of chromium is 5~100μg / dm ^2. Although the amount of pinholes tends to increase as the adhesion amount of nickel and chromium increases, the number of pinholes is suppressed within this range. Terms of peeling ultrathin copper layer without unevenness uniformly, and, from the viewpoint of suppressing a pinhole, 300~10000μg / dm ² adhesion amount of nickel, be 10-50 / dm ² adhesion amount of chromium preferably, 500~3000μg / dm ² adhesion amount of nickel, the adhesion amount of chromium and more preferably to 12~30μg / 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. In addition, 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 may be a single layer selected from the group consisting of copper, nickel, cobalt and zinc, or a layer made of an alloy containing one or more of them. Further, after roughening treatment or without roughening treatment, secondary particles, tertiary particles and / or rust preventive layers are formed of nickel, cobalt, copper, zinc alone or an alloy, and further on the surface. Treatments such as chromate treatment and silane coupling treatment may be applied. That is, on the surface of the roughening treatment layer, one or more layers selected from the group consisting of a rust prevention layer, a chromate treatment layer and a silane coupling treatment layer may be formed, and on the surface of the ultrathin copper layer, You may form 1 or more types of layers selected from the group which consists of a rust prevention layer, a chromate treatment layer, and a silane coupling treatment layer.

<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. Ultra-thin bonded to an insulating substrate, bonded to an insulating substrate such as a base epoxy resin, glass cloth / glass nonwoven fabric composite epoxy resin and glass cloth base epoxy resin, polyester film, polyimide film, etc. The copper layer can be etched into the intended conductor pattern to finally produce a printed wiring board. 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.

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 these from the cross section of the copper foil carrier / intermediate layer / ultra thin copper layer, the maximum value of the Ni concentration is 40 to The minimum value of the Cu concentration at the location where Ni and Cu coexist is 95% by mass and 1-50% by mass.
Thus, 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, copper is present in a certain amount or more inside the nickel of the intermediate layer. As the copper concentration in the intermediate layer increases, the adhesion between the intermediate layer and the ultrathin copper layer increases. Therefore, the peel strength can be controlled by controlling the copper concentration in nickel.

When the copper foil with a carrier of the present invention is subjected to 50 to 1000 nm long STEM line analysis in a range including all of these from the cross section of the copper foil carrier / intermediate layer / ultra thin copper layer, the maximum value of the Cr concentration is 1 to 1. At 10% by mass, the Cr peak coexists with or is in contact with the Ni peak. Here, “peak” refers to the entire surface of a mountain waveform obtained by STEM line analysis, “coexistence” has a portion where they overlap, and “contact” refers to the hem and hem of the mountain. Indicates contact.
Thus, when the copper foil with carrier of the present invention is subjected to elemental analysis of copper foil carrier / intermediate layer / ultra thin copper layer, a certain amount of chromium is present near the ultra thin copper layer of the intermediate layer, and nickel Is higher in concentration than the outermost surface in contact with the ultrathin copper layer. For this reason, generation | occurrence | production of the pinhole in an ultra-thin copper layer side surface is suppressed favorably. In addition, in the copper foil with carrier after thermocompression bonding, when elemental analysis of the copper foil carrier / intermediate layer / ultra thin copper layer is performed, a certain amount of chromium is present near the ultra thin copper layer of the intermediate layer, and nickel However, the concentration is higher inside than the outermost surface. For this reason, generation | occurrence | production of the pinhole in an ultra-thin copper layer side surface is suppressed favorably.

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 the 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 from the cross section of the layer / ultra-thin copper layer, the maximum value of Ni concentration is 30 to 95% by mass, and Ni and Cu coexist It is preferable that the Cu concentration minimum value at the location to be 5 to 65% by mass.
As described above, in the copper foil with carrier after thermocompression bonding, when a cross section of the copper foil carrier / intermediate layer / ultra thin copper layer is subjected to elemental analysis, a certain amount or more of copper is present in the intermediate layer. For this reason, there exists an effect that the fall of the extreme peeling strength after thermocompression-bonding can be prevented. In addition, the presence of a certain amount or more of Ni in the intermediate layer has the effect of preventing excessive diffusion of copper into the intermediate layer and preventing an extreme increase in peel strength.
Note that the elemental analysis value of the metal mesh used for supporting the sample during STEM measurement varies greatly depending on the metal type. Therefore, a metal that does not affect the elemental analysis of the copper foil with a carrier of the present invention, for example, a mesh made of Mo is used for supporting the sample.

  The higher the current density at the time of nickel plating is set to increase the electrodeposition rate per unit time, and the higher the transport speed of the carrier copper foil, the lower the density of the nickel layer. When the density of the nickel layer is reduced, the copper of the carrier copper foil is easily diffused into the nickel layer, and the concentration of copper in the nickel can be controlled. Further, the chromate layer has a higher current density when the chromate treatment is performed, and when the transport speed of the carrier copper foil is decreased, the chromium concentration increases, and the chromium concentration can be controlled.

  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 Tables 1 and 2 is performed under 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: Went. Washing and pickling were performed between the processing steps on the carrier surface side and the ultrathin copper layer side.

・ Ni plating Nickel sulfate: 250-300 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

-Cr plating solution composition: chromic anhydride 200-400 g / L, sulfuric acid 1.5-4 g / L
pH: 1-4
Liquid temperature: 45-60 degreeC
Current density: 10 to 40 A / dm ²

Electrolytic chromate liquid composition (1): potassium dichromate 1-10 g / L, zinc 0-5 g / L
Liquid composition (2): Chromic anhydride 1-10 g / L
pH: 3-4
Liquid temperature: 50-60 degreeC
Current density: 0.1-2.6 A / dm ²
Coulomb amount: 0.5-30 As / dm ²

・ Immersion chromate treatment liquid composition (1): potassium dichromate 1-10 g / L, zinc 0-5 g / L
Liquid composition (2): Chromic anhydride 1-10 g / L
pH: 3-4
Liquid temperature: 50-60 degreeC
Immersion time: 1 to 20 seconds

Subsequently, on the roll-to-roll type continuous plating line, an ultrathin copper layer having a thickness of 3 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 2 and 5, 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 Cu: 10 to 20 g / L
Co: 1-10 g / L
Ni: 1 to 10 g / L
pH: 1-4
Temperature: 40-50 ° C
Current density Dk: 20 to 30 A / dm ²
Time: 1-5 seconds Cu adhesion amount: 15-40 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 Tables 1 and 2.

<Measurement of adhesion amount>
The nickel adhesion amount and the chromium adhesion amount were measured by ICP emission analysis after dissolving the sample with nitric acid having a concentration of 20% by mass. The chromium adhesion amount was obtained by dissolving the sample with hydrochloric acid having a concentration of 7% by mass, and atomic absorption. Measured by quantitative analysis by the method.

<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
A Mo mesh was used for supporting the sample, and the elemental concentration line analysis was performed for 50 to 1000 nm long 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. As for the mesh for supporting the sample, the elemental analysis value of the sample varies greatly depending on the metal type. However, when the Mo mesh is used, such a change in the analysis value is favorably suppressed.
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.

<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 11, pinholes were well suppressed, and even better peel strength was exhibited.
In Comparative Examples 1 and 2, since nickel and chromium were not present in the release layer, the carrier could not be released from the ultrathin copper layer even before pressing.
In Comparative Examples 3 and 9, since the amount of chromium deposited was small (the chromium concentration was low), the carrier could not be peeled after the substrates were bonded together.
In Comparative Examples 4, 5, 6 and 8, since the amount of nickel deposited was small (nickel concentration was low), the carrier could not be peeled from the ultrathin copper foil even before pressing.
In Comparative Example 7, since the amount of nickel deposited was too large (the nickel concentration was too high), pinholes in the ultrathin copper foil increased and the peel strength was too low.
In Comparative Example 10, since the amount of chromium attached to the chromate was too large, pinholes in the ultrathin copper foil increased, and the peel strength was too low.
In Comparative Example 11, chromium plating was used instead of chromate, and the nickel concentration was low, so that the carrier could not be peeled after the substrates were bonded together.
In Comparative Example 12, chrome plating was used instead of chromate, and the chromium concentration was high, so that many pinholes were generated.
FIG. 1 shows a concentration profile of a cross section before pressure bonding to a substrate according to Example 9. FIG. 2 shows a cross-sectional concentration profile after pressure bonding of the substrate according to the ninth embodiment. FIG. 3 shows a concentration profile of a cross section after the substrate is crimped according to the fifth embodiment. FIG. 4 shows a concentration profile of a cross section after the substrate is crimped according to Comparative Example 3.

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 a nickel layer and a chromate layer in this order on the copper foil carrier,
The amount of adhered 100~40000μg / dm ² of the intermediate layer of nickel, the adhesion amount of chromium is 5~100μg / dm ^2,
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 these, the maximum value of Ni concentration is 40 to 95% by mass, and The copper foil with a carrier whose minimum value of Cu density | concentration of the location where Ni and Cu coexist is 1-50 mass%.   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, the maximum value of Cr concentration is 1 to 10% by mass, and the peak of Cr The copper foil with a carrier according to claim 1, wherein coexists with or is in contact with a peak of Ni. When the insulating substrate is thermocompression bonded to the ultra-thin 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 these, the maximum value of Ni concentration is 30 to 95% by mass, and The copper foil with a carrier according to claim 1 or 2, wherein a Cu concentration minimum value at a location where Ni and Cu coexist is 5 to 65 mass%.   The copper foil with a carrier according to any one of claims 1 to 3, 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 1-4 which have a roughening process layer in the said ultra-thin copper layer surface.   The copper foil with a carrier according to claim 5, 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 any one or more kinds.   The copper foil with a carrier of Claim 5 or 6 which has 1 or more types of layers selected from the group which consists of a rust preventive layer, a chromate process layer, and a silane coupling process layer on the surface of the said roughening process layer.   The copper with a carrier according to any one of claims 1 to 7, 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. The copper foil with a carrier as described in any one of Claims 1-8 which has a copper- phosphorus alloy between the said intermediate | middle layer and the said ultra-thin copper layer. After forming nickel plating on the copper foil carrier, including a step of forming an intermediate layer by forming a chromate layer by electrolytic chromate, and a step of forming an ultrathin copper layer by electrolytic plating on the intermediate layer The manufacturing method of the copper foil with a carrier as described in any one of Claims 1-9 . The manufacturing method of the copper foil with a carrier of Claim 10 which strike-plats with a copper-phosphorus alloy on the chromate layer of the said intermediate | middle layer, and forms an ultra-thin copper layer on it. The manufacturing method of the copper foil with a carrier of Claim 10 or 11 including the process of forming a roughening process layer further on the said ultra-thin copper layer. The copper foil with a carrier manufactured by the manufacturing method of the copper foil with a carrier according to any one of claims 1 to 9 , or the copper foil with a carrier according to any one of claims 10 to 12. method for manufacturing a printed wiring board for producing a print wiring board Te.

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