Patent ID: 8872036

Claim:
A producing method of a suspension board with circuit, wherein the suspension board with circuit comprises an insertion portion configured to be inserted into an E-block, and wherein the insertion portion is defined along an entire widthwise direction of the suspension board with circuit, the producing method comprising the steps of: preparing a metal supporting board and an insulating base layer formed on the metal supporting board; forming a conductive pattern on the insulating base layer; and forming an insulating cover layer on the insulating base layer so as to cover the conductive pattern, wherein the step of forming the insulating cover layer includes: forming a photosensitive layer on the insulating base layer and the conductive pattern; a first exposure step of disposing a first photomask so as to expose, to light, a portion of the photosensitive layer corresponding to the insertion portion, and shield, from light, the other portion of the photosensitive layer, and performing exposure; a second exposure step of disposing a second photomask so as to expose, to light, a portion of the photosensitive layer where the insulating cover layer including the insertion portion is to be formed, and shield, from light, the portion of the photosensitive layer where the insulating cover layer is not to be formed, and performing exposure; a development step of developing the photosensitive layer exposed to light by the first exposure step and the second exposure step to pattern the photosensitive layer such that a thickness T 1 of the photosensitive layer in the insertion portion is larger than a thickness T 2 of the photosensitive layer in a portion other than the insertion portion; and a curing step of curing the photosensitive layer after the development step, and wherein a thickness of the metal supporting board is 10 to 60 μm, wherein a thickness of the insulating base layer is 1 to 30 μm, wherein a thickness of the conductive pattern is 5 to 20 μm, wherein the thickness T 1 of the insertion portion is 6 to 8.5 μm, and wherein the thickness T 2 of the portion other than the insertion portion is 4.5 to 7 μm.