A circuit board including a substrate, a first circuit layer, a first insulating layer, a second circuit layer, and a solder resist layer is provided. The first circuit layer is disposed on the substrate. The first insulating layer is disposed on the substrate and covers a portion of the first circuit layer. The second circuit layer is disposed on the first insulating layer and penetrates a portion of the first insulating layer to electrically connect the first circuit layer. The solder resist layer is disposed on the substrate and covers a portion of the second circuit layer.

To provide a surface-treated copper foil that is capable of favorably decreasing the transmission loss even used in a high frequency circuit board and has an improved peel strength on adhering to an insulating substrate, such as a resin. A surface-treated copper foil containing a copper foil, and a surface treatment layer containing a roughening treatment layer on at least one surface of the copper foil, wherein on observation of the copper foil from the side of the surface having the roughening treatment layer, the roughening treatment layer has an average length of roughening particles of 0.030 m or more and 0.8 m or less, the roughening treatment layer has an average number of gap portions between the adjacent roughening particles of 20/100 m or more and 1,700/100 m or less, and the roughening treatment layer has a total frequency of an overlap frequency and a contact frequency of roughening particles of 120/100 m or less.

The invention is directed to a method of bonding a hermetically sealed electronics package to an electrode or a flexible circuit and the resulting electronics package, that is suitable for implantation in living tissue, such as for a retinal or cortical electrode array to enable restoration of sight to certain non-sighted individuals. The hermetically sealed electronics package is directly bonded to the flex circuit or electrode by electroplating a biocompatible material, such as platinum or gold, effectively forming a studbump connection, which bonds the flex circuit to the electronics package. The resulting electronic device is biocompatible and is suitable for long-term implantation in living tissue.

The invention provides a process for forming a multi-layer film including the steps of: (1) forming an under layer film onto a substrate by coating an under layer film material containing a resin represented by the following general formula (1) in which a compound having a bisnaphthol group has been made a novolac resin, and curing the same by heat treatment at a temperature in a range of 300 C. or higher and 700 C. or lower for 10 seconds to 600 seconds, (2) forming a silicon film onto the under layer film, (3) forming a hydrocarbon film onto the silicon film by coating a hydrocarbon film material, and (4) forming a silicon-oxidized film onto the hydrocarbon film by coating a silicon-oxidized film material. There can be provided a process for forming a multi-layer film which can reduce reflectance, and useful for a patterning process with high dimensional accuracy of dry etching. ##STR00001##

The invention is directed to a method of bonding a hermetically sealed electronics package to an electrode or a flexible circuit and the resulting electronics package, that is suitable for implantation in living tissue, such as for a retinal or cortical electrode array to enable restoration of sight to certain non-sighted individuals. The hermetically sealed electronics package is directly bonded to the flex circuit or electrode by electroplating a biocompatible material, such as platinum or gold, effectively forming a studbump connection, which bonds the flex circuit to the electronics package. The resulting electronic device is biocompatible and is suitable for long-term implantation in living tissue.