TWI617436B - Ultra-thin copper foil with carrier, manufacturing method thereof, copper laminated board and printed wiring board - Google Patents

Abstract

The invention provides an ultra-thin copper foil with a carrier, which can achieve the effects of both laser drilling processability and fine circuit formation in the processing of copper laminates and the manufacture of printed wiring boards. The ultra-thin copper foil with a carrier of the present invention includes a carrier foil, a release layer, and an ultra-thin copper foil in this order. The surface on the release layer side of the ultra-thin copper foil has an average distance between peaks of the surface (Peak Spacing) of 2.5 to 20.0 μm, and a core roughness depth Rk of 1.5 to 3.0 μm. On the side opposite to the peeling layer side of the ultra-thin copper foil, the maximum height difference Wmax of the undulation was 4.0 μm or less.

Description

Ultra-thin copper foil with carrier, manufacturing method thereof, copper laminated board and printed wiring board

The present invention relates to an ultra-thin copper foil with a carrier, a method for manufacturing the same, a copper sheet laminate, and a printed wiring board.

In the past, the subtractive process method was widely used as a manufacturing method of printed wiring boards. The subtractive process method is a method of forming fine circuits using copper foil. For example, as shown in FIGS. 1 and 2, the lower base material 12 a includes an insulating resin substrate 12 including a lower-layer circuit 12 b, and the insulating resin substrate 12 is bonded to the roughened surface of the copper foil 10 via a prepreg 14 ( In step (a)), after the copper foil 10 is ultra-thinned by half-etching (step (b)), the through hole 16 is formed by laser drilling as appropriate (step (c)). Next, electroless copper plating 18 (step (d)) and electroplated copper 20 (step (e)) are performed, and a predetermined pattern is masked by using the dry film 22 for exposure and development (step (f)), and an etching method is used. After unnecessary copper foils and the like under the opening of the dry film 22 are dissolved and removed (step (g)), the dry film 22 is peeled off (step (h)) to form a wiring 24 having a predetermined pattern.

In addition, in recent years, through-hole processing of copper laminates has been Lasers are often used to directly irradiate ultra-thin copper foil and form through holes. For example, Patent Document 1 (JP 2001-326467A) discloses a method for manufacturing a printed wiring board including a recessed portion such as a through hole formed in a copper laminated board, by using corrugated copper as an outer copper foil of the copper laminated board. For foil, a direct laser drilling method can be used to simultaneously remove copper foil and substrate resin using carbon dioxide laser. In addition, Patent Document 2 (JP H11-346060A) discloses that after the surface of an ultra-thin copper foil is subjected to a blackening treatment, the blackened surface is irradiated with a carbon dioxide laser to insulate the ultra-thin copper foil and the insulation thereunder. Layer for drilling.

[Prior technical literature] [Patent Literature]

[Patent Document 1] JP 2001-326467 A

[Patent Document 2] JP H11-346060 A

[Patent Document 3] JP H9-241882 A

However, the method using the corrugated copper foil disclosed in Patent Document 1 has high workability of laser drilling, but may also deteriorate the formation of fine circuits. Therefore, it is desirable to ensure high laser drilling. At the same time of workability, the formation of fine circuits is further improved. On the other hand, as for the blackening treatment disclosed in Patent Document 2, in addition to the time and cost, the yield is also low. Therefore, it is desirable to directly perform the blackening treatment without performing the blackening treatment. The surface of the ultra-thin copper foil is laser-drilled to achieve a good condition.

The inventors of the present invention have found that in this ultra-thin copper foil with a carrier, by providing an average distance (Peak Spacing) between surface peaks of the surface of the release layer side of the ultra-thin copper foil, 2.5 to 20.0 μm, The core roughness depth Rk is 1.5 to 3.0 μm. On the opposite side of the peeling layer side of the ultra-thin copper foil, the maximum height difference Wmax of the distribution is 4.0 μm or less. The processing of the copper laminated board and the manufacture of the printed wiring board can achieve the effects of both laser drillability and fine circuit formation.

Therefore, the object of the present invention is to provide an ultra-thin copper foil with a carrier, which can achieve the effects of both laser drilling processability and fine circuit formation in the processing of copper laminates and the manufacture of printed wiring boards. .

According to one aspect of the present invention, there is provided a carrier-side ultra-thin copper foil including a carrier foil, a release layer, and an ultra-thin copper foil in order: a surface on the release layer side of the ultra-thin copper foil, The average peak distance between the surface peaks (Peak Spacing) is 2.5 to 20.0 μm, and its core roughness depth Rk is 1.5 to 3.0 μm. On the opposite side of the peeling layer side of the ultra-thin copper foil, the The maximum height difference Wmax of the undulation is 4.0 μm or less.

According to another aspect of the present invention, a manufacturing method for manufacturing the ultra-thin copper foil with a carrier in the above aspect is provided, including: A step of preparing a carrier foil having a surface having an average distance between valleys (Valley Spacing) of 2.5 to 20.0 μm and a core roughness depth Rk of 2.0 to 3.8 μm; forming a peel on the aforementioned surface of the aforementioned carrier foil A step of forming a layer; a step of forming an ultra-thin copper foil on the aforementioned surface of the aforementioned carrier foil.

According to still another aspect of the present invention, there is provided a copper sheet laminate including the ultra-thin copper foil with a carrier as described above.

According to still another aspect of the present invention, there is provided a printed wiring board manufacturing method using the above-mentioned ultra-thin copper foil with a carrier to produce a printed wiring board.

12a‧‧‧ground substrate

12b‧‧‧Lower circuit

12‧‧‧ insulating resin substrate

14‧‧‧ Prepreg

10‧‧‧ Copper foil

16‧‧‧through hole

18‧‧‧Electroless copper plating

20‧‧‧ Electroplated copper

22‧‧‧ dry film

24‧‧‧ Wiring

32‧‧‧ Core Department

34‧‧‧ high protruding peak

36‧‧‧ deep protruding valley

30‧‧‧ Rough curve

32a‧‧‧Upgrade

32b‧‧‧ lower level

[Fig. 1] A flowchart showing the steps of the subtraction process. The first half is a diagram showing steps (steps (a) to (d)).

[Fig. 2] A flowchart showing the steps of the subtraction process. The first half is a diagram showing steps (steps (e) to (h)).

[Fig. 3] An explanatory sectional view defining a core roughness depth Rk.

[Embodiment] definition

The specific parameters of the invention are defined as follows.

The “Peak spacing” on the surface of this specification is: from the information about the unevenness of the sample surface measured by a stereo surface structure analysis microscope, removing the undulating components, and filtering the waveform data about the peaks And the average distance between the peaks in the extracted data.

The "Valley spacing" in this specification is: from the information about the unevenness of the sample surface measured by a stereo surface structure analysis microscope, after removing the undulating components, the waveform data about the valley is filtered out and extracted In the data, the average distance between its valleys.

The “core roughness depth Rk” in this specification is a parameter determined in accordance with JIS B 0671-2: 2002. As shown in FIG. 3, the core portion of the roughness curve 30 (roughness core profile) The difference between the upper level 32a and the lower level 32b of 32); The "core portion of the rough curve" 30 is a curve in which the high protruding peak portion 34 and the deep protruding valley portion 36 are removed from the rough curve. The rough curve 30 shown in FIG. 3 is a portion taken from a portion corresponding to the evaluation length ln, and the right side is an equivalent curve 38 for reference.

The "maximum height difference Wmax" of this specification is: from the information on the unevenness of the sample surface measured by a stereo surface structure analysis microscope, the height of the waveform data when the waveform data about the fluctuation is extracted by using a filter The maximum difference (the sum of the maximum peak height and maximum valley depth of the waveform).

The "ten-point average roughness Rzjis" in this specification is a parameter determined based on JIS B 0601: 2001. The rough height curve of the reference length is calculated from the highest peak to the fifth highest height. And the average value of the valley depth from the deepest peak to the fifth-deepest depth, the sum of the average value of the height of the mountain and the average depth of the valley.

Either the peak spacing of the surface (Peak spacing), the valley spacing (Valley spacing), the core roughness depth (core roughness depth) Rk, the maximum height difference Wmax, and the ten-point average roughness Rzjis, any of A commercially available three-dimensional surface structure analysis microscope (for example: zygo New View 5032 (manufactured by Zygo)) and a commercially available analysis software (for example: Metro Pro Ver. 8.0.2) can be set under the condition of a low-frequency filter 11 μm And measured. In this case, it is preferable that the non-measurement surface of the foil and the sample stage are tightly fixed, and within a range of 1 cm of the sample piece, 6 points are selected for measurement with a field of view of 108 μm × 144 μm, and the 6 points are selected from the measurement points. The average value of the obtained measured values is adopted as a representative value.

In this specification, the "electrode surface" of the carrier foil is the surface on the side connected to the cathode when the carrier foil is produced.

In this specification, the "precipitation surface" of the carrier foil is the surface on the precipitation side of the electrolytic copper when the carrier foil is produced, that is, the surface on the side not connected to the cathode.

Ultra-thin copper foil with carrier and manufacturing method thereof

The ultra-thin copper foil with a carrier of the present invention includes a carrier foil, a release layer, and an ultra-thin copper foil in this order. Moreover, on the surface of the release layer side of the ultra-thin copper foil, the The average peak distance between the surface peaks (Peak Spacing) is 2.5 to 20.0 μm, and its core roughness depth Rk is 1.5 to 3.0 μm. In addition, the maximum height difference Wmax of the undulation on the side opposite to the release layer side of the ultra-thin copper foil is 4.0 μm or less. Thereby, the processing of the copper laminated board and the manufacture of the printed wiring board can simultaneously achieve the effects of both laser drillability and fine circuit formation. Furthermore, in order to ensure the workability of laser drilling, the present invention does not require a blackening treatment which has been conventionally used.

Originally, if the ultra-thin copper foil was not blackened, it would be difficult to achieve the effects of both laser drilling processability and fine circuit formation, but the present invention can achieve such effects at the same time unexpectedly. Originally, in order to obtain excellent fine circuit formation, the surface on the opposite side of the release layer is required to be a smooth ultra-thin copper foil. Therefore, in order to obtain such an ultra-thin copper foil, the surface on the side of the release layer must be a smooth ultra-thin copper foil. This smooth surface makes the laser easily reflected, so the laser will not be easily superimposed. Absorption by thin copper foil leads to a decrease in the workability of laser drilling. In fact, as mentioned above, the method using the corrugated copper foil disclosed in Patent Document 1 has high workability of laser drilling, but may also deteriorate the formation of fine circuits. In order to solve this problem, the ultra-thin copper foil with a carrier of the present invention can improve the formability of fine circuits while ensuring high laser drillability. The following method can achieve the effect of having both laser drilling workability and fine circuit formation property. That is, the average distance between the peaks of the surface of the surface of the peeling layer side of the ultra-thin copper foil is increased by setting the difference Rk of the core portion of the surface of the surface of the peeling layer side of the ultrathin copper foil to 1.5 μm or more Spacing) is 2.5 ~ 20.0μm, can realize high direct laser drilling workability. In particular, as shown in FIG. 3, the core roughness depth Rk of the core portion 32 is different from the ten-point average roughness Rzjis; the core roughness depth Rk is: the high protruding peak portion 34 and The deep protruding valley portion 36 is a curve obtained by removing the rough curve 30. Based on the difference between the upper level 32a and the lower level 32b of this curve, Rk can be said to be a parameter obtained by defining a minute space on the surface of the foil. Therefore, it means that the higher the value of Rk, the larger the space will be. The reflection of the laser makes it easy to store heat in the high space (that is, the space of heat storage becomes larger because of the reflection of the laser). In addition, since the average distance between peaks on the surface (Peak Spacing) is 2.5 to 20.0 μm, the rough peaks become denser, and the irradiated laser becomes easier to be absorbed, that is, it is easily converted into heat. Therefore, as a multiplication effect between controlling Rk and controlling Peak Spacing, the direct laser drilling processability can be improved. Thereafter, the maximum step height difference Wmax of the undulation of the core portion of the surface on the release layer side of the ultra-thin copper foil is set to be 3.0 μm or less, and on the surface opposite to the release layer side of the ultra-thin copper foil When it is 4.0 μm or less, it is possible to achieve an effect of improving the formability of a fine circuit without reducing the high laser drilling processability. In other words, the inventors of the present invention have found that the main reason for reducing the formability of fine circuits is because of the undulations on the side opposite to the peeling layer side of the ultra-thin copper foil, and the maximum height difference of the undulations is controlled ( Wmax) is 4.0 μm or less, which contributes to improvement of fine circuit formation. In particular, since the upper limit value of the maximum undulation Wmax of 4.0 μm is not an extremely low value, extreme smoothness is not required on the side opposite to the peeling layer side of the copper foil. (Subject to roughening), which is particularly suitable for this surface profile. In addition, methods other than the subtraction process method (for example, MSAP (Modified Semi-Additive Method)) are also applicable. In any case, in the ultra-thin copper foil with a carrier of the present invention, by controlling the Peak spacing, Rk, and Wmax in the ultra-thin copper foil (especially the ultra-thin copper foil used in the subtractive process method), the In addition to direct electron beam drilling processability, it is possible to realize the formation of a fine circuit suitable for forming a circuit having a line / space = 30 μm or less / 30 μm or less.

Therefore, the ultra-thin copper foil has a surface on the side of the release layer whose average peak distance between the peaks (Peak Spacing) is 2.5 to 20.0 μm, and whose core roughness depth Rk is 1.5 to 3.0 μm, and The surface on the opposite side to the peeling layer having a maximum height difference Wmax of 4.0 μm or less. By making these parameters within the above range, the processing of the copper laminated board and the manufacture of the printed wiring board can simultaneously achieve the effects of both laser drillability and fine circuit formation. The surface on the release layer side of the ultra-thin copper foil has an average distance between peaks (Peak Spacing) of 2.5 to 20.0 μm, and preferably 6.5 to 15.0 μm. The surface on the side of the release layer of the ultra-thin copper foil has a core roughness depth Rk of 1.5 to 3.0 μm, preferably 2.0 to 3.0 μm. In addition, on the side opposite to the release layer side of the ultra-thin copper foil, the maximum height difference Wmax of the undulation is 4.0 μm or less, preferably 3.0 μm or less, and more preferably 2.5 μm or less. In particular, in order to form a fine circuit with a line / space = 25 μm or less / 25 μm or less, it is preferable that the Wmax on the surface of the ultra-thin copper foil is 3.0 μm or less. The lower the Wmax, the better. Although the lower limit is not particularly limited, Wmax is typically 0.1 μm or more, and more typically 0.2 μm or more.

The ten-point average roughness Rzjis of the surface on the release layer side of the ultra-thin copper foil is preferably 2.0 to 4.0 μm, and more preferably 2.5 to 4.0 μm. Within this range, it can contribute to the balance between laser drilling processability and fine circuit formation. On the other hand, on the side opposite to the release layer of the ultra-thin copper foil, the ten-point average roughness Rzjis is preferably 4.0 μm or less, more preferably 3.0 μm or less, and even more preferably 2.5 μm or less. Within this range, it can contribute to the improvement of fine circuit formation. The ten-point average roughness Rzjis is typically 0.5 μm or more, and more typically 1.0 μm or more, from the viewpoint of adhesion with the resin layer.

The surface opposite to the release layer side of the ultra-thin copper foil is preferably a roughened surface. That is, it is preferable to apply a roughening treatment to one side of the ultra-thin copper foil. Thereby, when manufacturing a copper laminated board and a printed wiring board, the adhesiveness with a resin layer can be improved. In this roughening treatment, it is preferable to use at least two kinds of conventional methods including a firing coating process for depositing and depositing fine copper particles on an ultra-thin copper foil and a coating process for preventing the fine copper particles from falling off. Coating Engineering Method. The surface opposite to the peeling layer side of the ultra-thin copper foil is a roughened surface, and it is preferable to satisfy the above-mentioned ten-point average roughness Rzjis.

In addition to the above-mentioned unique surface profile, the ultra-thin copper foil is not particularly limited to a conventional structure using an ultra-thin copper foil with a carrier. For example, ultra-thin copper foil can be formed by using a wet film formation method such as electroless copper plating method and electrolytic copper plating method, a dry film formation method such as sputtering and chemical vapor deposition, or a combination of these methods. The thickness of the ultra-thin copper foil is preferably 0.5 to 5.0 μm. For example: In order to form a fine circuit with a line / space = 25 μm or less / 25 μm or less, it is preferable that the Wmax on the surface of the ultra-thin copper foil is 3.0 μm or less.

The release layer is a layer having the following functions: weakening the peeling strength of the carrier foil, ensuring stability of the strength, and suppressing interdiffusion between the carrier foil and the copper foil which is easily caused during high-temperature imprint molding. The release layer is generally formed on one side of the carrier foil, but may be formed on both sides. The release layer may be either an organic release layer or an inorganic release layer. Examples of the organic component used in the organic release layer include an organic compound containing nitrogen, an organic compound containing sulfur, and a carboxylic acid. As the nitrogen-containing organic compound, for example, a triazole compound, an imidazole compound, and the like, among them, it is preferable from the standpoint of the release stability of the triazole compound. Examples of triazole compounds are: 1,2,3-benzotriazole, carboxybenzotriazole, N ', N'-bis (benzotriazolylmethyl) urea, 1H-1,2, 4-triazole, and 3-amino-1H-1,2,4-triazole. Examples of organic compounds containing sulfur include mercaptobenzene, thiocyanuric acid, 2-benzimidazolethiol, and the like. Examples of carboxylic acids are: monocarboxylic acids, dicarboxylic acids, and the like. On the other hand, examples of the inorganic component used in the inorganic release layer include Ni, Mo, Co, Cr, Fe, Ti, W, P, Zn, and a chromate-treated film. The release layer can be formed by contacting at least one surface of the carrier foil with a solution containing a release layer component and fixing the release layer component to the surface of the carrier foil. When the carrier foil is brought into contact with a solution containing a release layer component, the contact includes immersion in a solution containing a release layer component, spraying of a solution containing a release layer component, and flowing down of a solution containing a release layer component. In addition, a vapor-phase coating such as a vapor deposition method or a sputtering method may be used to form the release layer component. In addition, fixing the release layer component to the surface of the carrier foil is: adsorption of a solution containing the release layer component And dry, electrodeposition of the release layer components in the solution containing the release layer components. The thickness of the release layer is typically 1 nm to 1 μm, and preferably 5 nm to 500 nm.

The carrier foil is a foil that supports ultra-thin copper foil and improves handling properties. Examples of the carrier foil include aluminum foil, copper foil, stainless steel (SUS) foil, and resin film coated with metal on the surface. Copper foil is preferred. The copper foil may be a rolled copper foil or an electrolytic copper foil. The thickness of the carrier foil is typically 250 μm or less, and preferably 12 μm to 200 μm.

The surface on the release layer side of the carrier foil has a valley spacing of 2.5 to 20.0 μm, and a core roughness depth Rk of 2.0 to 3.8 μm. In the manufacturing process of ultra-thin copper foil with a carrier, in order to form an ultra-thin copper foil on the side of the release layer side of the carrier foil, by providing the above-mentioned low Valley spacing and Rk on the surface of the carrier foil in advance, it can be used in ultra-thin The surface on the release layer side of the copper foil and the surface on the opposite side to the release layer provide the aforementioned desired surface profile. That is, the ultra-thin copper foil with a carrier of the present invention is prepared with a surface having an average distance between valleys (Valley Spacing) of 2.5 to 20.0 μm and a core roughness depth (Rk of 2.0 to 3.8 μm). A carrier foil is produced by forming a release layer on the surface of the carrier foil and forming an ultra-thin copper foil on the release layer. The ten-point average roughness Rzjis of the surface on the release layer side of the carrier foil is preferably 2.0 to 5.0 μm. The surface of the carrier foil on the side of the release layer preferably has a valley spacing of 4.5 to 10.0 μm. The realization of Valley spacing, Rk, and Rzjis within the above range on the surface of the carrier foil is: the electrolyte (such as sulfuric acid acid sulfuric acid Copper solution) After applying activated carbon treatment to remove the residual additive solution in the electrolytic solution, the additive solution such as gelatin or gelatin is added to the electrolytic solution treated with activated carbon, and electrolysis under conventional conditions is preferably performed. An electrolytic copper foil having a thickness of about 15 to 35 μm is manufactured (for example, refer to the manufacturing method described in Patent Document 3 (JP H9-241882 A)). The ultra-thin copper foil is formed by separating the release layer on the carrier foil deposition surface provided with such a desired surface profile, and the above-mentioned surface profile can be provided on the side of the release layer side of the ultra-thin copper foil.

If necessary, another functional layer may be provided between the release layer and the carrier foil and / or ultra-thin copper foil. Examples of such other functional layers include auxiliary metal layers. The auxiliary metal layer is preferably composed of nickel and / or cobalt. By forming the auxiliary metal layer on the surface side of the carrier foil and / or on the surface side of the ultra-thin copper foil, it is possible to suppress the mutual diffusion easily caused between the carrier foil and the copper foil during high-temperature or long-time hot-space stamping, It can also ensure the stability of the peeling strength of the carrier foil. The thickness of the auxiliary metal layer is preferably 0.001 to 3 μm.

If necessary, anti-rust treatment can be applied to ultra-thin copper foil. The rust prevention treatment is preferably a coating treatment containing zinc. The coating treatment using zinc may be any of a zinc coating treatment and a zinc alloy coating treatment, and the zinc alloy coating treatment is particularly preferably a zinc-nickel alloy treatment. The zinc-nickel alloy treatment may be at least a plating treatment containing Ni and Zn, and may also contain other elements such as Sn, Cr, and Co. Ni / Zn adhesion to zinc-nickel alloy coatings is better when the mass ratio is 1.2 ~ 10, more preferably 2 ~ 7, and even more preferably 2.7 ~ 4. In addition, the rust prevention treatment preferably further includes a chromate treatment, which is After the zinc-plated coating treatment, it is preferable to perform the coating on the surface of the zinc-containing coating. This can further improve rust prevention. Particularly preferred rust prevention treatment is a combination of chromate treatment after zinc-nickel alloy plating treatment.

If necessary, a silane coupling agent treatment may be applied to the surface of the ultra-thin copper foil to form a silane coupling agent layer. This can improve moisture resistance, chemical resistance, and adhesion to resins and the like. The silane coupling agent layer can be formed by appropriately diluting the silane coupling agent, coating it, and drying it. Examples of the silane coupling agent include epoxy-functional silane coupling agents such as tetra-glycidyl ether trimethyl, γ-glycidoxy, γ-aminopropyltrimethoxy, and N-β (aminoethyl ester). ) γ-aminopropyltrimethoxy, N-3- (4- (3-aminopropoxy) butoxy) propyl-3-aminopropyltrimethyl, N-phenyl-γ-aminopropyltrimethyl Amino-functional silane coupling agents such as oxygen, thiol-functional silane coupling agents such as γ-mercaptopropyltrimethoxysilane, or olefins such as vinyltrimethoxysilane and vinylphenyltrimethoxysilane Functional silane coupling agent, acrylic functional silane coupling agent such as γ-methacryloxysilane, or imidazole functional silane coupling agent such as imidazole silane, or triazine functionality such as triazine silane Silane coupling agents, etc.

Copper laminated board

It is preferable that the ultra-thin copper foil with a carrier of this invention is a copper laminated board for making printed wiring boards. That is, according to a preferred aspect of the present invention, a copper sheet laminated board obtained by using ultra-thin copper foil with a carrier is provided. By using the ultra-thin copper foil with a carrier of the present invention, it is possible to achieve both the effects of laser drillability and fine circuit formation in the processing of a copper laminate. The copper sheet The laminated board includes the ultra-thin copper foil with a carrier of the present invention, and a resin layer provided in close contact with the surface treatment layer. The ultra-thin copper foil with a carrier can be provided on one or both sides of the resin layer. The resin layer is a resin, and preferably contains an insulating resin. The resin layer is preferably a prepreg and / or a resin sheet. The prepreg is a general term for composite materials in which synthetic resin plates, glass plates, glass woven fabrics, glass non-woven fabrics, and paper are immersed in synthetic resin. Preferred examples of the insulating resin include epoxy resin, cyanate resin, bismaleimide triazine resin (BT resin), polyphenylene ether resin, and phenol resin. Examples of the insulating resin constituting the resin sheet include insulating resins such as epoxy resin, polyimide resin, and polyester resin. In addition, from the viewpoint of improving the insulation of the resin layer and the like, it may contain filler particles composed of various inorganic particles such as silicon dioxide and alumina. Although the thickness of the resin layer is not particularly limited, it is preferably 1 to 1000 μm, more preferably 2 to 400 μm, and even more preferably 3 to 200 μm. The resin layer may be composed of a plurality of layers. A resin layer such as a prepreg and / or a resin sheet may be provided on an ultra-thin copper foil with a carrier through an undercoat resin layer previously coated on the surface of the copper foil.

Printed wiring board

The ultra-thin copper foil with a carrier of the present invention is preferably used for producing a printed wiring board. That is, according to a preferred aspect of the present invention, a printed wiring board obtained by using an ultra-thin copper foil with a carrier is provided. By using the ultra-thin copper foil with a carrier of the present invention, in the production of a printed wiring board, it is possible to achieve the effects of both laser drilling processability and fine circuit formation. The printed wiring board according to this aspect has a layered structure in which a resin layer and a copper layer are sequentially laminated. Copper layer is from The layer from the ultra-thin copper foil with the carrier ultra-thin copper foil of this invention. In addition, the resin layer is related to the above-mentioned copper laminate. In any case, in addition to using the ultra-thin copper foil with a carrier of the present invention, the printed wiring board may have a conventional layered structure. As a specific example of the printed wiring board, the ultra-thin copper foil of the present invention is adhered on one or both sides of the prepreg and cured, and the printed wiring is formed on one or both sides of the circuit after being laminated. Boards, multilayer printed wiring boards, and the like. In addition, as another specific example, a flexible printed circuit wiring board, a COF, a TAB tape, etc. may be formed by forming an ultra-thin copper foil of the present invention on a resin film to form a circuit. As another specific example, a resin-coated copper foil (RCC) coated with the resin layer is formed on the ultra-thin copper foil of the present invention, and the resin layer is used as an insulating adhesive material layer and laminated on the printed substrate. Then, the ultra-thin copper foil is used as all or a part of the wiring layer, and a laminated wiring board is formed by a method such as a modified semi-additive (MSAP) method and a subtractive process method, and a semi-additive method is used after removing the ultra-thin copper foil. Laminated wiring boards that form circuits, laminates with resin copper foil that are exchanged on semiconductor integrated circuits, and circuits that are directly laminated on a wafer, etc. As a more specific development example, an antenna element for forming a laminated circuit by forming the copper foil with resin on a substrate as described above, and an electronic material for panel display in which a laminated pattern is formed on glass and a resin film by an adhesive layer. And electronic materials for glass windows, electromagnetic wave protective films, etc., which are coated with a conductive adhesive on the ultra-thin copper foil of the present invention. In particular, the ultra-thin copper foil with a carrier of the present invention is applicable to a subtractive process method. For example, when a circuit is formed by a subtractive process method, the configuration shown in FIG. 1 and FIG. 2 may be adopted.

[Example]

Hereinafter, the present invention will be further described using examples.

example 1

After the release layer and the ultra-thin copper foil layer are sequentially formed on the precipitation surface side of the carrier foil, a rust prevention treatment and a silane coupling agent treatment are performed to produce an ultra-thin copper foil with a carrier. Therefore, various evaluations were performed about the obtained ultra-thin copper foil with a carrier. The details are shown in the following order.

(1) Preparation of carrier foil

The cathode uses a titanium rotary electrode with an arithmetic mean roughness Ra (JIS B 0601: 2001) based on 0.20 μm. The anode uses DSA (Dimensional Stability Anode) as a copper electrolyte. The sulfuric acid and sulfuric acid with the following composition are used. After the copper solution was treated with activated carbon, water-soluble gelatin was added to the electrolytic solution after the activated carbon treatment to a concentration of 5 mg / L, and the electrolyte was electrolyzed at a solution temperature of 50 ° C and a current density of 60 A / dm ^{2 to} obtain an electrolytic copper having a thickness of 18 μm The foil was used as the carrier foil.

<Composition of acidic copper sulfate solution>

Copper concentration: 85g / L

Sulfuric acid concentration: 270g / L

Chlorine concentration: 30mg / L

(2) Formation of peeling layer

The precipitated surface of the pickled carrier foil was placed in a CBTA (carboxybenzobenzotriazole) concentration of 1 g / L, a sulfuric acid concentration of 150 g / L, and a copper concentration of 10 g / L in an aqueous solution of CBTA. The immersion in seconds caused the components of CBTA to be adsorbed on the precipitation surface of the carrier foil. Thereby, the CBTA layer is formed as an organic peeling layer on the deposition surface of the carrier foil.

(3) Subsidized metal layer formation

The carrier foil forming the organic release layer was immersed in a solution containing nickel concentration of 20 g / L made of nickel sulfate, and the adhesion amount was equivalent to a thickness of 0.001 μm under the conditions of a liquid temperature of 45 ° C., a pH of 3, and a current density of 5 A / dm ² Of nickel adheres to the organic release layer. Thereby, a nickel layer is formed as an auxiliary metal layer on the organic release layer.

(4) Formation of ultra-thin copper foil

The carrier foil forming the auxiliary metal layer was immersed in a copper solution having the composition shown below, and was electrolyzed at a solution temperature of 50 ° C and a current density of 5 to 30 A / dm ^{2 to} form an ultra-thin copper foil with a thickness of 3 μm on the auxiliary metal layer. .

<Composition of solution>

Copper concentration: 60g / L

Sulfuric acid concentration: 200g / L

(5) Roughening

The surface of the ultra-thin copper foil thus formed is roughened. This roughening treatment is composed of a firing coating process for depositing and depositing fine copper particles on an ultra-thin copper foil, and a covering coating process for preventing the fine copper particles from falling off. The firing coating process uses an acidic copper sulfate solution containing a copper concentration of 10 g / L and a sulfuric acid concentration of 120 g / L to perform a roughening treatment at a liquid temperature of 25 ° C and a current density of 15 A / dm ² . The subsequent coating process uses an acidic copper sulfate solution containing a copper concentration of 70 g / L and a sulfuric acid concentration of 120 g / L to perform electrodeposition under smooth coating conditions at a liquid temperature of 40 ° C and a current density of 15 A / dm ² .

(6) Anti-rust treatment

The surface of the roughened layer of the obtained ultra-thin copper foil with a carrier was subjected to a rust prevention treatment consisting of a zinc-nickel alloy plating treatment and a chromate treatment. First, an electrolytic solution having a zinc concentration of 0.2 g / L, a nickel concentration of 2 g / L, and a potassium pyrrolinate concentration of 300 g / L was used at a liquid temperature of 40 ° C and a current density of 0.5 A / dm ² to roughen the layer. And the surface of the carrier foil is treated with zinc-nickel alloy plating. Next, the surface of the zinc-nickel alloy plating treatment was subjected to a chromate treatment using an aqueous solution having a chromic acid concentration of 3 g / L under conditions of pH 10 and a current density of 0.5 A / dm ² .

(7) Silane coupling agent treatment

An aqueous solution having a γ-glycidyl oxide concentration of 2 g / L was adsorbed on the surface of the ultra-thin copper foil side of the ultra-thin copper foil with a carrier, and the water was evaporated by an electric heater to perform a silane coupling agent treatment. At this time, the silane coupling agent treatment is not performed on the carrier foil side.

(8) Evaluation

The obtained ultra-thin copper foil with a carrier was subjected to various evaluations described below.

<Surface properties parameter>

Zygo New View 5032 (manufactured by Zygo) was used as the measurement device, and Metro Pro Ver 8.0.2 was used as the analysis software. The low-frequency filter was used under the condition of 11 μm. The average distance (Peak spacing), the average distance between valleys (Valley spacing), the ten-point average roughness Rzjis, the core roughness depth Rk, and / or the maximum height difference Wmax of the fluctuations were measured. At this time, the ultra-thin copper foil or carrier foil is tightly fixed to the sample stage, and within a 1 cm angle of the sample piece, 6 points are selected for measurement with a field of view of 108 μm × 144 μm, and the measurement points obtained from the 6 points The average value of the measured values is taken as the representative value. In addition, the surface of the release layer side of the ultra-thin copper foil was measured after producing a copper laminate sheet for laser drilling processability evaluation described later.

<Laser Drilling Processability>

A copper laminated laminate was produced by using an ultra-thin copper foil with a carrier, and the laser drilling processability was evaluated. First, an ultra-thin copper foil with a carrier ultra-thin copper foil was laminated on the surface of the inner substrate via a prepreg (830 N-A, manufactured by Mitsubishi Gas Chemical Co., Ltd., 0.2 mm thick) at 4.0 MPa and 220 ° C After hot pressing at 90 minutes, the carrier foil was peeled off to produce a copper laminate. After that, a carbon dioxide laser was applied to the copper laminated laminate with a pulse width of 12 μsec. Laser drilling was performed under conditions of an energy of 8 mJ and a laser beam diameter of 97 μm. The diameters in the x direction and the y direction of the ten holes formed by laser drilling were measured, and the average of these diameters was calculated as the processed hole diameter. The pore diameter after processing was determined to be A or more, A to 65 μm or less and 70 μm or less to be B, and C or less to 65 μm.

<Circuitability>

The evaluation of the circuit formability was performed in the following manner. First, electroplating was continued until the circuit height of the surface of the said copper laminated board became 15 micrometers. A dry film is attached to the surface of the plated layer formed in this manner, and exposure and development are performed to form an etching photoresist. Through the treatment of the copper chloride etching solution, copper between the photoresists is dissolved and removed, and a wiring pattern having a circuit height of 15 μm and a line / space = 25 μm / 25 μm is formed. Observe the upper part of the circuit by SEM, measure the value of 50 points from the top of the circuit with the length of the hemming at 4 μm, and calculate the average value as the hemming length. A hemming length of less than 4.5 μm was determined as A, a length of 4.5 μm or more and less than 5.0 μm was determined as B, and a length of 5.0 μm or more was determined as C.

Example 2

The production and evaluation of the ultra-thin copper foil with a carrier were performed in the same manner as in Example 1 except that the ultra-thin copper foil was formed in the following procedure.

(Formation of ultra-thin copper foil)

The carrier foil forming the auxiliary metal layer was immersed in a brightening solution of the composition shown below, and was electrolyzed at a solution temperature of 45 to 50 ° C and a current density of 33 A / dm ^{2 to} form an ultra-thin copper foil with a thickness of 3 μm on the auxiliary metal layer. .

<Composition of plating solution>

Copper concentration: 65g / L

Sulfuric acid concentration: 200g / L

Diallyl dimethyl ammonium chloride concentration: 40mg / L

Bis (3-sulfopropyl) disulfide concentration: 30mg / L

Chlorine concentration: 30mg / L

Example 3

The production and evaluation of an ultra-thin copper foil with a carrier were performed in the same manner as in Example 2 except that a carrier foil having a thickness of 35 μm was produced.

Example 4 (comparative)

Except that a carrier foil was formed in the following procedure, production and evaluation of an ultra-thin copper foil with a carrier were performed in the same manner as in Example 1.

(Production of carrier foil)

As a copper electrolyte, a sulfuric acidic copper sulfate solution with the composition shown below was used. The cathode used a titanium rotary electrode with a surface roughness Ra of 0.20 μm. The anode used DSA (Dimensional Stability Anode). The solution temperature was 50 ° C and the current density was 50. 60A / dm ^{2 was} electrolyzed to obtain an electrolytic copper foil having a thickness of 35 μm as a carrier foil.

<Composition of acidic copper sulfate solution>

Copper concentration: 80g / L

Sulfuric acid concentration: 250g / L

Gelatin concentration: 2mg / L

Chlorine concentration: 1.5mg / L

Example 5 (comparative)

Except that a carrier foil having a thickness of 35 μm was produced, as in Example 1, an ultra-thin copper foil with a carrier was produced and evaluated.

result

The evaluation results obtained in Examples 1 to 5 are shown in Table 1.

Claims (11)

An ultra-thin copper foil with a carrier comprising a carrier foil, a release layer, and an ultra-thin copper foil in sequence, wherein the average distance between the peaks of the surfaces of the surface on the release-layer side of the ultra-thin copper foil (Peak Spacing) ) Is 2.5 to 20.0 μm, and its core roughness depth Rk is 1.5 to 3.0 μm; on the side opposite to the release layer side of the ultra-thin copper foil, the maximum height difference Wmax is 4.0 μm the following. The ultra-thin copper foil with a carrier according to claim 1, wherein the ten-point average roughness Rzjis of the surface on the release layer side of the ultra-thin copper foil is 2.0 to 4.0 μm. The ultra-thin copper foil with a carrier according to claim 1, wherein the surface on the release layer side of the ultra-thin copper foil has an average distance between peaks on the surface (Peak Spacing) of 6.5 to 15.0 μm, and its core is rough The core roughness depth Rk is 2.0 to 3.0 μm. The ultra-thin copper foil with a carrier according to claim 1, wherein the maximum height difference Wmax of the undulation on the side opposite to the release layer side of the ultra-thin copper foil is 3.0 μm or less. The ultra-thin copper foil with a carrier according to claim 1, wherein the surface opposite to the release layer side of the ultra-thin copper foil is a roughened surface. The ultra-thin copper foil with a carrier according to claim 1, wherein the ultra-thin copper foil has a thickness of 0.5 to 5.0 μm. A manufacturing method for manufacturing the ultra-thin copper foil with a carrier according to any one of claims 1 to 6, comprising: A step of preparing a carrier foil having a surface having an average distance between valleys (Valley Spacing) of 2.5 to 20.0 μm and a core roughness depth Rk of 2.0 to 3.8 μm; forming a peel on the aforementioned surface of the aforementioned carrier foil A step of forming a layer; a step of forming an ultra-thin copper foil on the aforementioned release layer. The manufacturing method according to claim 7, wherein the ten-point average roughness Rzjis of the surface of the carrier foil is 2.0 to 5.0 μm. The manufacturing method according to claim 7, wherein the average distance (Valley Spacing) between the valleys on the surface of the carrier foil is 4.5 to 10.0 μm. The copper sheet laminated board provided with the ultra-thin copper foil with a carrier as described in any one of Claims 1-6. A method for manufacturing a printed wiring board, comprising: manufacturing a printed wiring board by using the ultra-thin copper foil with a carrier according to any one of claims 1 to 6.