Patent ID: 7194799

Claim:
A process for fabricating a high density multi-layer microcoil comprising steps of: providing a substrate; using photolithography process to form a dry film photoresist structure with a coil tunnel having coil elements perpendicular to said substrate and two outlets at ends of said tunnel; and injecting a conductive material with low melting point into said tunnel and forming a coil winding, wherein said steps of forming said photoresist structure depend on number of windings in each coil element; for a coil element with N windings, said windings are numbered as 1 to N from inner to outer; each coil is winding is composed of a top parallel portion, a bottom parallel portion and two vertical portions and formed as a planar coil element perpendicular to said substrate; said photoresist structure is made by 4N+1 times of deposition, comprising steps of: depositing first to 2Nth photoresist materials, using photolithography to form said lower half portions of said 1 to N windings of said coil elements; said lower haft portions comprises bottom parallel portions and lower halves of vertical portions; depositing 2N+1 to 4Nth photoresist materials, using photolithography process to form said upper half portions of said N to 1 windings of said coil elements; said upper haft portions comprises upper halves of vertical portions and top parallel portions; and depositing last (4N+1) photoresist material, using photolithography to form a top of said photoresist structure.