A method for forming a hollow microneedle structure includes processing the front side of a wafer to form at least one microneedle projecting from a substrate and a through-bore passing through the microneedle and through a thickness of the substrate. An entire length of the through-bore is formed by a dry etching process performed from the front side of the wafer. Most preferably, upright surfaces of the microneedle structure and the through bore of the structure are formed by dry etching performed via a single mask with differing depths obtained by harnessing aspect ratio limitations of the dry etching process.