Roughened copper foil, copper-clad laminate and printed wiring board
Provided is a roughened copper foil capable of achieving both excellent transmission characteristics and suppression of powdering. This roughened copper foil includes a roughened surface on at least one side. The roughened surface has a roughness slope tan θ of 0.58 or less as calculated based on a mean height Rc (μm) and a mean width RSm (μm) of profile elements by formula Rc/(0.5×RSm), and a sharpness index Rc×Sku of 2.35 or less that is a product of the mean height Rc (μm) and a kurtosis Sku. Rc and RSm are values measured in accordance with JIS B0601-2013 under a condition of not performing a cutoff by a cutoff value λs and a cutoff value λc, and Sku is a value measured in accordance with ISO 25178 under a condition of not performing a cutoff using an S filter and an L filter.
1. A roughened copper foil comprising a roughened surface on at least one side,
wherein the roughened surface has a roughness slope tan θ of 0.58 or less as calculated based on a mean height Rc (μm) and a mean width RSm (μm) of profile elements by formula Rc/(0.5×RSm), and
wherein the roughened surface has a sharpness index Rc×Sku of 2.35 or less that is a product of the mean height Rc (μm) and a kurtosis Sku,
wherein Rc and RSm are values measured in accordance with JIS B0601-2013 under a condition of not performing a cutoff by a cutoff value λs and a cutoff value λc, and Sku is a value measured in accordance with ISO 25178 under a condition of not performing a cutoff using an S filter and an L filter.
2. The roughened copper foil according to claim 1 , wherein the roughened surface has a developed interfacial area ratio Sdr of 15.0% or more and 30.0% or less, wherein Sdr is a value measured in accordance with ISO 25178 under a condition of not performing a cutoff using the S filter and the L filter.
3. The roughened copper foil according to claim 1 , wherein the roughened surface has the mean height Rc of 0.40 μm or more and 0.60 μm or less.
4. The roughened copper foil according to claim 1 , wherein the roughened surface has an arithmetic mean height Sa of 0.15 μm or more and 0.33 μm or less, wherein Sa is a value measured in accordance with ISO 25178 under a condition of not performing a cutoff using the S filter and the L filter.
5. The roughened copper foil according to claim 1 , wherein the roughened surface has a root mean square height Sq of 0.23 μm or more and 0.40 μm or less, wherein Sq is a value measured in accordance with ISO 25178 under a condition of not performing a cutoff using the S filter and the L filter.
6. The roughened copper foil according to claim 1 , wherein the roughened surface has the mean width RSm of the profile elements of 2.80 μm or more and 6.00 μm or less.
7. The roughened copper foil according to claim 1 , further comprising a rust proofing layer and/or a silane coupling agent layer on the roughened surface.
8. The roughened copper foil according to claim 1 , wherein the roughened copper foil is an electrodeposited copper foil, and the roughened surface is present on an electrode side of the electrodeposited copper foil.
9. A copper-clad laminate comprising the roughened copper foil according to claim 1 .
10. A printed wiring board comprising the roughened copper foil according to claim 1 .