PRODUCTION OF THREE-DIMENSIONAL CIRCUIT BOARD

摘要

PURPOSE:To form circuits with high-density wirings on the three-dimensional circuit board having large ruggedness differences. CONSTITUTION:The three-dimensional circuit board is produced by including a stage for applying a photoresist 3 on the front surface of the three-dimensional circuit board 1 molded of a resin, superposing a photomask 4 thereon and exposing the photoresist with collimated beams of light, then developing the photoresist. The exposing is executed by using the photomask 4 formed with light transmission parts 4a subjected to the size adjustment meeting the spread of the collimated beams of light according to the spacing between the photomask 4 and the circuit forming surface of the circuit board 1 at this time. The process is so constituted that the exposure can be made by correcting the spread of the collimated beams of light by the spacing between the circuit board 1 and the photomask 4, by which the nonuniformity in the width size of the circuit 6 occurring in the ruggedness on the surface of the circuit board 1 is averted.