A micro-transformer manufacturing method is provided, which can improve throughput, prevent a crack from entering an insulating film between coils, and manufacture the micro-transformer without using a mask material having a high selection ratio. A first inflatable air cell is disposed in the central region and extends generally from at least the ball of the foot to at least the heel of the foot. The feedback reports comprise a first feedback report, a second feedback report and a third feedback report. At least one or more higher strength elongated sides, for example a second elongate side, may be comprised of a closed or box shaped side.