JP7017369B2 - Surface-treated copper foil, copper-clad laminate and printed wiring board - Google Patents

Description

The present disclosure relates to surface-treated copper foil, copper-clad laminates and printed wiring boards.

In recent years, with the increasing needs for miniaturization and high performance of electronic devices, fine pitching (miniaturization) of circuit patterns (also referred to as "conductor patterns") for printed wiring boards mounted on electronic devices is required. ing.
As a method for manufacturing a printed wiring board, various methods such as a subtractive method and a semi-additive method are known. Among them, in the subtractive method, an insulating base material is adhered to a copper foil to form a copper-clad laminate, and then a resist is applied and exposed on the surface of the copper foil to form a predetermined resist pattern, and a resist pattern is formed. A circuit pattern is formed by removing the unused portion (unnecessary portion) by etching.

In response to the above-mentioned request for fine pitch, for example, in Patent Document 1, the surface of a copper foil is roughened by copper-cobalt-nickel alloy plating, and then a cobalt-nickel alloy plating layer is formed, and further. It is described that by forming a zinc-nickel alloy plating layer, a surface-treated copper foil capable of fine pitching a circuit pattern can be obtained.

Japanese Patent No. 2849059

However, in the conventional surface-treated copper foil, the etching rate of the surface-treated layer (plating layer) is slower than the etching rate of the copper foil, so that the surface spreads from the copper foil surface (top) toward the insulating base material (bottom). There is a problem that the etching factor of the circuit pattern is lowered due to the etching. If the etching factor of the circuit pattern is low, it is necessary to widen the space between adjacent circuits, which makes it difficult to make the circuit pattern fine pitch.

The present disclosure has been made to solve the above-mentioned problems, and provides a surface-treated copper foil and a copper-clad laminate capable of forming a circuit pattern having a high etching factor suitable for fine pitching. The purpose is to do.
It is also an object of the present disclosure to provide a printed wiring board having a circuit pattern with a high etching factor.

As a result of diligent research to solve the above problems, the present inventors have formed surface-treated layers on both sides of the copper foil, and controlled the amount of Ni that is difficult to dissolve in the etching solution in the surface-treated layer. By doing so, it has been found that the etching factor of the circuit pattern can be increased, and the present disclosure has been made.

That is, the present disclosure includes a copper foil, a first surface-treated layer formed on one surface of the copper foil, and a second surface-treated layer formed on the other surface of the copper foil. A surface-treated copper foil used for adhering a first surface-treated layer to an insulating base material and etching from the second surface-treated layer side to form a circuit pattern, wherein Ni adhesion of the second surface-treated layer is performed. The present invention relates to a surface-treated copper foil in which the ratio of the Ni adhesion amount of the first surface-treated layer to the amount is 0.01 to 2, and the Zn adhesion amount of the first surface-treated layer is 400 to 500 μg / dm ² .
The present disclosure also relates to a copper-clad laminate comprising the surface-treated copper foil and an insulating base material adhered to a first surface-treated layer of the surface-treated copper foil.
Further, the present disclosure relates to a printed wiring board having a circuit pattern formed by etching the surface-treated copper foil of the copper-clad laminate.

According to the present disclosure, it is possible to provide a surface-treated copper foil and a copper-clad laminate capable of forming a circuit pattern having a high etching factor suitable for fine pitching.
Further, according to the present disclosure, it is possible to provide a printed wiring board having a circuit pattern having a high etching factor.

It is sectional drawing of the copper-clad laminated board using the surface-treated copper foil of this disclosure. It is sectional drawing for demonstrating the manufacturing method of the printed wiring board by the subtractive method.

Hereinafter, embodiments of the present disclosure will be specifically described with reference to the drawings. The present disclosure is not limited to the following embodiments, and changes, improvements, etc. may be made to the following embodiments as appropriate based on the ordinary knowledge of those skilled in the art, without departing from the spirit of the present disclosure. It should be understood that any of these are also within the scope of this disclosure.

FIG. 1 is a cross-sectional view of a copper-clad laminate using the surface-treated copper foil of the present disclosure.
The surface-treated copper foil 1 comprises a copper foil 2, a first surface-treated layer 3 formed on one surface of the copper foil 2, and a second surface-treated layer 4 formed on the other surface of the copper foil 2. Have. Further, the copper-clad laminate 10 has a surface-treated copper foil 1 and an insulating base material 11 adhered to the first surface-treated layer 3 of the surface-treated copper foil 1.

The first surface treatment layer 3 and the second surface treatment layer 4 contain at least Ni as an adhering element.
In the surface-treated copper foil 1, the ratio of the Ni adhesion amount of the first surface-treated layer 3 to the Ni adhesion amount of the second surface-treated layer 4 is 0.01 to 2, preferably 0.8 to 1.5. Since Ni is a component that is difficult to dissolve in the etching solution, by setting the ratio of the amount of Ni adhered to the above range, the first surface treatment layer that becomes the bottom side of the circuit pattern when etching the copper-clad laminate 10. It is possible to promote the dissolution of 3 and delay the dissolution of the second surface treatment layer 4, which is the top side of the circuit pattern. Therefore, it is possible to obtain a circuit pattern in which the difference between the top width and the bottom width is small and the etching factor is high.

The amount of Ni attached to the first surface treatment layer 3 is not particularly limited as long as the ratio of the amount of attached Ni is within the above range, but is preferably 20 to 200 μg / dm ² , and more preferably 20 to 100 μg / dm ² . .. By setting the amount of Ni adhered to the first surface treatment layer 3 within the above range, the etching factor of the circuit pattern can be stably increased.

The first surface treatment layer 3 can contain elements such as Zn, Co, and Cr in addition to Ni as an adhering element.
The amount of Zn adhered to the first surface treatment layer 3 is not particularly limited because it depends on the type of the first surface treatment layer 3, but when Zn is contained in the first surface treatment layer 3, it is preferably 20 to 1000 μg / dm. ² , more preferably 400 to 500 μg / dm ² . By setting the amount of Zn adhered to the first surface treatment layer 3 within the above range, the etching factor of the circuit pattern can be stably increased.

The amount of Co adhered to the first surface treatment layer 3 is not particularly limited because it depends on the type of the first surface treatment layer 3, but is preferably 1500 μg / dm ² or less, more preferably 0.1 to 500 μg / dm ² , and further. It is preferably 0.5 to 100 μg / dm ² . By setting the amount of Co adhered to the first surface treatment layer 3 within the above range, the etching factor of the circuit pattern can be stably increased. Further, since Co is a magnetic metal, the amount of Co adhered to the first surface treatment layer 3 is suppressed to 100 μg / dm ² or less, preferably 0.5 to 100 μg / dm ² , so that the printed wiring has excellent high frequency characteristics. A surface-treated copper foil 1 capable of producing a plate can be obtained.

The amount of Cr adhered to the first surface treatment layer 3 is not particularly limited because it depends on the type of the first surface treatment layer 3, but is 500 μg / dm ² or less, more preferably 0.5 to 300 μg / dm ² , and even more preferably. It is 1 to 100 μg / dm ² . By setting the amount of Cr adhered to the first surface treatment layer 3 within the above range, the etching factor of the circuit pattern can be stably increased.

The Rzjis of the first surface treatment layer 3 is not particularly limited, but is preferably 0.3 to 1.5 μm , and more preferably 0.5 to 0.8 μm . By setting the Rzjis of the first surface treatment layer 3 within the above range, the adhesiveness with the insulating base material 11 can be improved.
Here, "Rzjis" in the present specification means a ten-point average roughness defined in JIS B0601: 2001.

The type of the first surface treatment layer 3 is not particularly limited as long as the ratio of the Ni adhesion amount is within the above range, and various surface treatment layers known in the art can be used. Examples of the surface treatment layer include a roughening treatment layer, a heat resistant layer, a rust preventive layer, a chromate treatment layer, a silane coupling treatment layer and the like. These layers can be used alone or in combination of two or more. Among them, the first surface-treated layer 3 preferably has a roughened-treated layer from the viewpoint of adhesiveness to the insulating base material 11.
Here, the "roughened layer" in the present specification is a layer formed by the roughening treatment, and includes a layer of roughened particles. Further, in the roughening treatment, normal copper plating or the like may be performed as a pretreatment, or normal copper plating or the like may be performed as a finishing treatment to prevent the roughened particles from falling off. The "roughened layer" in the book includes layers formed by these pretreatments and finishing treatments.

The roughened particles are not particularly limited, but are formed from any simple substance selected from the group consisting of copper, nickel, cobalt, phosphorus, tungsten, arsenic, molybdenum, chromium and zinc, or an alloy containing any one or more thereof. can do. Further, after forming the roughened particles, it is also possible to perform a roughening treatment in which secondary particles and tertiary particles are further provided with a simple substance or an alloy of nickel, cobalt, copper, zinc or the like.

The heat-resistant layer and the rust-preventive layer are not particularly limited, and can be formed from a material known in the art. Since the heat-resistant layer may also function as a rust-preventive layer, one layer having both the functions of the heat-resistant layer and the rust-preventive layer may be formed as the heat-resistant layer and the rust-preventive layer.
The heat-resistant layer and / or rust-preventive layer includes nickel, zinc, tin, cobalt, molybdenum, copper, tungsten, phosphorus, arsenic, chromium, vanadium, titanium, aluminum, gold, silver, platinum group elements, iron, and tantalum. It can be a layer containing one or more elements selected from the above (which may be in any form such as metal, alloy, oxide, nitride, sulfide, etc.). Examples of the heat-resistant layer and / or the rust-preventive layer include a layer containing a nickel-zinc alloy.

The chromate-treated layer is not particularly limited and can be formed from a material known in the art.
Here, the term "chromate-treated layer" as used herein means a layer formed of a liquid containing chromic anhydride, chromic acid, chromic acid, chromate or dichromate. The chromate-treated layer can be any element (metal, alloy, oxide, nitride, sulfide, etc.) such as cobalt, iron, nickel, molybdenum, zinc, tantalum, copper, aluminum, phosphorus, tungsten, tin, arsenic, and titanium. It can be a layer containing). Examples of the chromate-treated layer include a chromate-treated layer treated with an aqueous solution of chromic acid anhydride or potassium dichromate, and a chromate-treated layer treated with a treatment liquid containing chromic acid anhydride or potassium dichromate and zinc.

The silane coupling treatment layer is not particularly limited and can be formed from a material known in the art.
Here, the term "silane coupling-treated layer" as used herein means a layer formed of a silane coupling agent.
The silane coupling agent is not particularly limited, and those known in the art can be used. Examples of the silane coupling agent include an amino-based silane coupling agent, an epoxy-based silane coupling agent, and a mercapto-based silane coupling agent. These can be used alone or in combination of two or more.

The type of the second surface treatment layer 4 is not particularly limited as long as the ratio of the Ni adhesion amount is within the above range, and various surface treatment layers known in the art are used as in the first surface treatment layer 3. be able to. Further, the type of the second surface treatment layer 4 may be the same as or different from that of the first surface treatment layer 3.

The amount of Ni attached to the second surface treatment layer 4 is not particularly limited as long as the ratio of the amount of attached Ni is within the above range, but is preferably 0.1 to 500 μg / dm ² , more preferably 0.5 to 200 μg /. It is dm ² , more preferably 1 to 100 μg / dm ² . By setting the amount of Ni adhered to the second surface treatment layer 4 within the above range, the etching factor of the circuit pattern can be stably increased.

The second surface treatment layer 4 can contain elements such as Zn and Cr as adhesion elements in addition to Ni.
The amount of Zn adhered to the second surface treatment layer 4 is not particularly limited because it depends on the type of the second surface treatment layer 4, but when Zn is contained in the second surface treatment layer 4, it is preferably 10 to 1000 μg / dm. ² , more preferably 50 to 500 μg / dm ² , still more preferably 100 to 300 μg / dm ² . By setting the amount of Zn adhered to the second surface treatment layer 4 within the above range, the etching factor of the circuit pattern can be stably increased.

The amount of Cr adhered to the second surface treatment layer 4 is not particularly limited because it depends on the type of the second surface treatment layer 4, but when Cr is contained in the second surface treatment layer 4, it preferably exceeds 0 μg / dm ² . It is 500 μg / dm ² or less, more preferably 0.1 to 100 μg / dm ² , and even more preferably 1 to 50 μg / dm ² . By setting the amount of Cr adhered to the second surface treatment layer 4 within the above range, the etching factor of the circuit pattern can be stably increased.

The copper foil 2 is not particularly limited, and may be either an electrolytic copper foil or a rolled copper foil. Copper foil is generally manufactured by electrolytically depositing copper on a titanium or stainless steel drum from a copper sulfate plating bath, but the flat S-plane (shine surface) formed on the drum side is the opposite of the S-plane. It has an M surface (matte surface) formed on the side. Since the M surface of the electrolytic copper foil has irregularities, the first surface treatment layer 3 is formed on the M surface of the electrolytic copper foil and the second surface treatment layer 4 is formed on the S surface of the electrolytic copper foil. The adhesiveness between the surface treatment layer 3 and the insulating base material 11 can be enhanced.

The material of the copper foil 2 is not particularly limited, but when the copper foil 2 is a rolled copper foil, tough pitch copper (JIS H3100 alloy number C1100) and oxygen-free copper (JIS H3100) usually used as a circuit pattern of a printed wiring board are used. High-purity copper such as alloy number C1020 or JIS H3510 alloy number C1011) can be used. Further, for example, a copper alloy such as Sn-containing copper, Ag-containing copper, a copper alloy to which Cr, Zr or Mg is added, and a Corson-based copper alloy to which Ni and Si are added can also be used. In addition, in this specification, "copper foil 2" is a concept including a copper alloy foil.

The thickness of the copper foil 2 is not particularly limited, but may be, for example, 1 to 1000 μm, 1 to 500 μm, 1 to 300 μm, 3 to 100 μm, 5 to 70 μm, 6 to 35 μm, or 9 to 18 μm. can.

The surface-treated copper foil 1 of the present disclosure having the above-mentioned structure can be manufactured according to a method known in the art. Here, the ratio of the Ni adhesion amount and the Ni adhesion amount of the first surface treatment layer 3 and the second surface treatment layer 4 can be controlled by changing, for example, the type and thickness of the surface treatment layer to be formed. Further, the Rzjis of the first surface treatment layer 3 can be controlled by adjusting the formation conditions of the first surface treatment layer 3 and the like.

The copper-clad laminate 10 can be manufactured by adhering the insulating base material 11 to the first surface-treated layer 3 of the surface-treated copper foil 1.
The insulating base material 11 is not particularly limited, and those known in the art can be used. Examples of the insulating base material 11 include a paper base material phenol resin, a paper base material epoxy resin, a synthetic fiber cloth base material epoxy resin, a glass cloth / paper composite base material epoxy resin, a glass cloth / glass non-woven material composite base material epoxy resin, and the like. Examples thereof include a glass cloth base material epoxy resin, a polyester film, a polyimide film, a liquid crystal polymer, and a fluororesin.

The method for adhering the surface-treated copper foil 1 and the insulating base material 11 is not particularly limited, and can be performed according to a method known in the art. For example, the surface-treated copper foil 1 and the insulating base material 11 may be laminated and thermocompression bonded.

The copper-clad laminate 10 manufactured as described above can be used for manufacturing a printed wiring board. The method for manufacturing the printed wiring board is not particularly limited, and a known method such as a subtractive method or a semi-additive method can be used. Among them, the copper-clad laminate 10 is most suitable for use in the subtractive method.

FIG. 2 is a cross-sectional view for explaining a method of manufacturing a printed wiring board by a subtractive method.
In FIG. 2, first, a predetermined resist pattern 20 is formed by applying and exposing a resist on the surface of the surface-treated copper foil 1 of the copper-clad laminated plate 10 (step (a)). Next, the surface-treated copper foil 1 in the portion (unnecessary portion) where the resist pattern 20 is not formed is removed by etching (step (b)). Finally, the resist pattern 20 on the surface-treated copper foil 1 is removed (step (c)).
The various conditions in this subtractive method are not particularly limited, and can be performed according to the conditions known in the art.

Hereinafter, the present disclosure will be described in more detail by way of examples, but the present disclosure is not limited to these examples.

(Example 1)
A rolled copper foil (HA-V2 foil manufactured by JX Nippon Mining & Metals Co., Ltd.) having a thickness of 12 μm is prepared, and a roughening treatment layer, a heat resistant layer and a chromate treatment layer are sequentially formed on one surface as a first surface treatment layer, and the other. A surface-treated copper foil was obtained by sequentially forming a heat-resistant layer and a chromate-treated layer as a second surface-treated layer on the surface. The conditions for forming each layer are as follows.

<Roughening treatment layer of the first surface treatment layer>
A roughened layer was formed by electroplating.
Plating solution composition: 10 to 20 g / L Cu, 50 to 100 g / L sulfuric acid Plating solution temperature: 25 to 50 ° C.
Electroplating conditions: Current is applied in two stages 1st stage: Current density 45.0 A / dm ² , Time 1.4 seconds, Coulomb amount 60.8 As / dm ²
Second stage: current density 4.1 A / dm ² , time 2.8 seconds, coulomb amount 11.8 As / dm ²

<Heat-resistant layer of the first surface treatment layer>
A heat resistant layer was formed by electroplating.
Plating solution composition: 1 to 30 g / L Ni, 1 to 30 g / L Zn
Plating solution pH: 2-5
Plating liquid temperature: 30 to 50 ° C
Electroplating conditions: current density 2.1 A / dm ² , time 0.7 seconds, coulomb amount 1.4 As / dm ²

<Chromate treatment layer of the first surface treatment layer>
A chromate-treated layer was formed by electroplating.
Plating solution composition: 1 to 10 g / L K ₂ Cr ₂ O ₇ , 0.01 to 10 g / L Zn
Plating solution pH: 2-5
Plating liquid temperature: 30 to 50 ° C
Electroplating conditions: current density 2.1 A / dm ² , time 1.4 seconds, coulomb amount 2.9 As / dm ²

<Heat-resistant layer of the second surface treatment layer>
A heat resistant layer was formed by electroplating.
Plating solution composition: 1 to 30 g / L Ni, 1 to 30 g / L Zn
Plating solution pH: 2-5
Plating liquid temperature: 30 to 50 ° C
Electroplating conditions: current density 2.1 A / dm ² , time 0.7 seconds, coulomb amount 1.4 As / dm ²

<Chromate treatment layer of the second surface treatment layer>
A chromate-treated layer was formed by immersion chromate treatment.
Chromate solution composition: 1 to 10 g / L K ₂ Cr ₂ O ₇ , 0.01 to 10 g / L Zn
Chromate solution pH: 2-5
Chromate liquid temperature: 30-50 ° C

(Example 2)
A surface-treated copper foil was obtained in the same manner as in Example 1 except that the conditions for forming the roughening-treated layer of the first surface-treated layer were changed as follows.
<Roughening treatment layer of the first surface treatment layer>
A roughened layer was formed by electroplating.
Plating solution composition: 10 to 20 g / L Cu, 50 to 100 g / L sulfuric acid Plating solution temperature: 25 to 50 ° C.
Electroplating conditions: Current is applied in two stages First stage: Current density 42.7 A / dm ² , Time 1.4 seconds, Coulomb amount 57.6 As / dm ²
Second stage: current density 3.8 A / dm ² , time 2.8 seconds, coulomb amount 11.1 As / dm ²

(Comparative Example 1)
A rolled copper foil (HA-V2 foil manufactured by JX Nippon Mining & Metals Co., Ltd.) having a thickness of 12 μm is prepared, and a roughening treatment layer, a heat-resistant layer (1), a heat-resistant layer (2) and a chromate treatment are prepared on one surface as a first surface treatment layer. A surface-treated copper foil was obtained by sequentially forming layers and sequentially forming a heat-resistant layer and a chromate-treated layer as a second surface-treated layer on the other surface. The conditions for forming each layer are as follows.

<Roughening treatment layer of the first surface treatment layer>
A roughened layer was formed by electroplating.
Plating solution composition: 10 to 20 g / L Cu, 1 to 10 g / L Co, 1 to 10 g / L Ni
Plating solution pH: 1-4
Plating liquid temperature: 30 to 50 ° C
Electroplating conditions: current density 32.9 A / dm ² , time 1.8 seconds, coulomb amount 58.3 As / dm ²

<Heat-resistant layer (1) of the first surface treatment layer>
The heat-resistant layer (1) was formed by electroplating.
Plating solution composition: 1 to 20 g / L Co, 1 to 20 g / L Ni
Plating solution pH: 1-4
Plating liquid temperature: 30-60 ° C
Electroplating conditions: current density 18.4 A / dm ² , time 0.4 seconds, coulomb amount 7.7 As / dm ²

<Heat-resistant layer (2) of the first surface treatment layer>
The heat-resistant layer (2) was formed by electroplating.
Plating solution composition: 1 to 30 g / L Ni, 1 to 30 g / L Zn
Plating solution pH: 2-5
Plating liquid temperature: 30 to 50 ° C
Electroplating conditions: current density 3.5 A / dm ² , time 0.4 seconds, coulomb amount 1.5 As / dm ²

<Chromate treatment layer of the first surface treatment layer>
A chromate-treated layer was formed by immersion chromate treatment.
Chromate solution composition: 1 to 10 g / L K ₂ Cr ₂ O ₇ , 0.01 to 10 g / L Zn
Chromate solution pH: 2-5
Chromate liquid temperature: 30-50 ° C

<Heat-resistant layer of the second surface treatment layer>
A heat resistant layer was formed by electroplating.
Plating solution composition: 1 to 30 g / L Ni, 1 to 30 g / L Zn
Plating solution pH: 2-5
Plating liquid temperature: 30 to 50 ° C
Electroplating conditions: current density 4.1 A / dm ² , time 0.4 seconds, coulomb amount 1.7 As / dm ²

<Chromate treatment layer of the second surface treatment layer>
A chromate-treated layer was formed by immersion chromate treatment.
Chromate solution composition: 1 to 10 g / L K ₂ Cr ₂ O ₇ , 0.01 to 10 g / L Zn
Chromate solution pH: 2-5
Chromate liquid temperature: 30-50 ° C

(Comparative Example 2)
A surface-treated copper foil was obtained in the same manner as in Comparative Example 1 except that the formation conditions of the roughened-treated layer and the heat-resistant layer (1) of the first surface-treated layer were changed as follows.
<Roughening treatment layer of the first surface treatment layer>
A roughened layer was formed by electroplating.
Plating solution composition: 10 to 20 g / L Cu, 1 to 10 g / L Co, 1 to 10 g / L Ni
Plating solution pH: 1-4
Plating liquid temperature: 30 to 50 ° C
Electroplating conditions: current density 31.5 A / dm ² , time 1.8 seconds, coulomb amount 55.8 As / dm ²

<Heat-resistant layer (1) of the first surface treatment layer>
The heat-resistant layer (1) was formed by electroplating.
Plating solution composition: 1 to 20 g / L Co, 1 to 20 g / L Ni
Plating solution pH: 1-4
Plating liquid temperature: 30-60 ° C
Electroplating conditions: current density 19.1 A / dm ² , time 0.4 seconds, coulomb amount 7.9 As / dm ²

(Comparative Example 3)
Comparative Example 1 except that the conditions for forming the roughening-treated layer, the heat-resistant layer (1) and the chromate-treated layer of the first surface-treated layer, and the heat-resistant layer and the chromate-treated layer of the second surface-treated layer were changed as follows. A surface-treated copper foil was obtained in the same manner as above.
<Roughening treatment layer of the first surface treatment layer>
A roughened layer was formed by electroplating.
Plating solution composition: 10 to 20 g / L Cu, 1 to 10 g / L Co, 1 to 10 g / L Ni
Plating solution pH: 1-4
Plating liquid temperature: 30 to 50 ° C
Electroplating conditions: current density 36.5 A / dm ² , time 0.9 seconds, coulomb amount 32.3 As / dm ²

<Heat-resistant layer (1) of the first surface treatment layer>
The heat-resistant layer (1) was formed by electroplating.
Plating solution composition: 1 to 20 g / L Co, 1 to 20 g / L Ni
Plating solution pH: 1-4
Plating liquid temperature: 30-60 ° C
Electroplating conditions: current density 22.2 A / dm ² , time 0.4 seconds, coulomb amount 9.2 As / dm ²

<Chromate treatment layer of the first surface treatment layer>
A chromate-treated layer was formed by electroplating.
Plating solution composition: 1 to 10 g / L K ₂ Cr ₂ O ₇ , 0.01 to 10 g / L Zn
Plating solution pH: 2-5
Plating liquid temperature: 30 to 50 ° C
Electroplating conditions: current density 1.1 A / dm ² , time 0.8 seconds, coulomb amount 0.9 As / dm ²

<Heat-resistant layer of the second surface treatment layer>
A heat resistant layer was formed by electroplating.
Plating solution composition: 1 to 30 g / L Ni, 1 to 30 g / L Zn
Plating solution pH: 2-5
Plating liquid temperature: 30 to 50 ° C
Electroplating conditions: current density 2.6 A / dm ² , time 0.4 seconds, coulomb amount 1.1 As / dm ²

<Chromate treatment layer of the second surface treatment layer>
A chromate-treated layer was formed by electroplating.
Plating solution composition: 1 to 10 g / L K ₂ Cr ₂ O ₇ , 0.01 to 10 g / L Zn
Plating solution pH: 2-5
Plating liquid temperature: 30 to 50 ° C
Electroplating conditions: current density 1.2 A / dm ² , time 0.4 seconds, coulomb amount 0.5 As / dm ²

The surface-treated copper foils obtained in the above Examples and Comparative Examples were evaluated as follows.
<Measurement of adhesion amount of each element in the first surface treatment layer and the second surface treatment layer>
The amount of Ni, Zn and Co adhered is quantitatively analyzed by the atomic absorption spectroscopy using an atomic absorption spectrophotometer (model: AA240FS) manufactured by VARIAN by dissolving each surface treatment layer in nitric acid having a concentration of 20% by mass. Measured by The amount of Cr adhered was measured by dissolving each surface-treated layer in hydrochloric acid having a concentration of 7% by mass and performing quantitative analysis by the atomic absorption method in the same manner as described above.

<Measurement of Rzjis of the first surface-treated layer of surface-treated copper foil>
Rzjis (10-point average roughness) was measured according to JIS B0601: 2001 using a contact roughness meter Surfcorder SE-3C manufactured by Kosaka Laboratory Co., Ltd. In this measurement, the measurement reference length is 0.8 mm, the evaluation length is 4 mm, the cutoff value is 0.25 mm, the feed speed is 0.1 mm / sec, and the measurement position is changed in the width direction of the surface-treated copper foil. The evaluation was performed 10 times, and the average value of the measured values of 10 times was used as the evaluation result.

<Evaluation of etching factor>
A copper-clad laminate was produced by laminating a polyimide substrate on the first surface-treated layer of the surface-treated copper foil, heating it at 300 ° C. for 1 hour, and crimping it. Next, a photosensitive resist was applied onto the second surface-treated layer of the surface-treated copper foil, exposed and developed to form a resist pattern having a width of L / S = 29 μm / 21 μm. Then, the exposed portion (unnecessary portion) of the surface-treated copper foil was removed by etching to obtain a printed wiring board having a copper circuit pattern having a width of L / S = 25 μm / 25 μm. The widths of L and S of the circuit pattern are the widths of the bottom surface of the circuit, that is, the surface in contact with the polyimide substrate. Etching was performed using spray etching under the following conditions.
Etching solution: Copper chloride aqueous solution Liquid temperature: 50 ° C
Spray pressure: 0.2MPa
Next, the formed circuit pattern was observed by SEM, and the etching factor (EF) was determined based on the following formula.
EF = circuit height / {(circuit bottom width-circuit top width) / 2}
The etching factor means that the larger the value, the larger the inclination angle of the side surface of the circuit.
The above evaluation results are shown in Table 1. In Table 1, the unit of Rzjis is μm.
The value of EF is the average value of the results of five experiments for each Example and Comparative Example.

As shown in Table 1, the surface-treated copper foils of Examples 1 and 2 in which the ratio of the Ni adhesion amount is in the range of 0.01 to 2 are Comparative Examples 1 to 2 in which the ratio of the Ni adhesion amount is out of the range. The etching factor (EF) was higher than that of 3.
As can be seen from the above results, according to the present disclosure, it is possible to provide a surface-treated copper foil and a copper-clad laminate capable of forming a circuit pattern having a high etching factor suitable for fine pitching.
Further, according to the present disclosure, it is possible to provide a printed wiring board having a circuit pattern having a high etching factor.

1 Surface-treated copper foil 2 Copper foil 3 First surface-treated layer 4 Second surface-treated layer 10 Copper-clad laminate 11 Insulation base material 20 Resist pattern

Claims (9)

It has a copper foil, a first surface-treated layer formed on one surface of the copper foil, and a second surface-treated layer formed on the other surface of the copper foil, and the first surface-treated layer is formed. A surface-treated copper foil used for adhering to an insulating base material and etching from the second surface-treated layer side to form a circuit pattern.
The ratio of the Ni adhesion amount of the first surface treatment layer to the Ni adhesion amount of the second surface treatment layer is 0.01 to 2 .
A surface-treated copper foil having a Zn adhesion amount of 400 to 500 μg / dm ² in the first surface-treated layer . The surface-treated copper foil according to claim 1, wherein the ratio of the Ni adhesion amount is 0.8 to 1.5. The surface-treated copper foil according to claim 1 or 2, wherein the amount of Ni adhered to the first surface-treated layer is 20 to 200 μg / dm ² . The surface-treated copper foil according to claim 3, wherein the amount of Ni adhered to the first surface-treated layer is 20 to 100 μg / dm ² . The surface-treated copper foil according to any one of claims 1 to 4 , wherein the Rzjis of the first surface-treated layer is 0.3 to 1.5 μm. The surface-treated copper foil according to claim 5 , wherein the Rzjis of the first surface-treated layer is 0.5 to 0.8 μm. The surface-treated copper foil according to any one of claims 1 to 6 , wherein the copper foil is a rolled copper foil. A copper-clad laminate comprising the surface-treated copper foil according to any one of claims 1 to 7 and an insulating base material adhered to a first surface-treated layer of the surface-treated copper foil. A printed wiring board comprising a circuit pattern formed by etching the surface-treated copper foil of the copper-clad laminate according to claim 8 .

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