Milling of flex foil with two conductive layers from both sides

A flex foil comprising:

• a substrate;
• a first conductive layer arranged on one surface of the substrate;
• a second conductive layer arranged on an opposite surface of the substrate;
• a first insulating layer arranged adjacent to the first conductive layer;
• and
• a second insulating layer arranged adjacent to the second conductive layer,
• wherein one side of the flex foil is dry milled using a first cliché pattern including raised portions and non-raised portions to selectively remove at least one of the first conductive layer and the first insulating layer, and
• wherein an opposite side of the flex foil is dry milled using a second cliché pattern including upper raised portions, lower raised portions and non-raised portions to selectively remove only the second insulating layer,
• wherein the upper raised portions of the second cliché pattern remove the second insulating layer on the opposite side of the flex foil at locations where the at least one of the first insulating layer and the first conductive layer are removed, and
• wherein the lower raised portions of the second cliché pattern remove the second insulating layer on the opposite side of the flex foil at locations where the at least one of the first insulating layer and the first conductive layer are not removed.

A flex foil, comprising:

• a substrate;
• a first conductive layer arranged on one surface of the substrate;
• a second conductive layer arranged on an opposite surface of the substrate;
• a first insulating layer arranged adjacent to the first conductive layer;
• and
• a second insulating layer arranged adjacent to the second conductive layer,
• wherein a first portion of the first insulating layer and the first conductive layer are milled to the one surface of the substrate at a first location,
• wherein a first portion of the second insulating layer is milled on the opposite surface of the substrate at the first location,
• a second portion of the first insulating layer and the first conductive layer are not milled on the one surface of the substrate at a second location, and
• a second portion of the second insulating layer is milled on the opposite surface of the substrate at the second location.