Suspension board with circuit and producing method thereof

A producing method of a suspension board with circuit comprising an insertion portion to be inserted into an E-block, 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 of the photosensitive layer in the insertion portion is larger than a thickness 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.

A producing method of a suspension board with circuit comprising an insertion portion to be inserted into an E-block, 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:
• a first-photosensitive-layer forming step of forming a first photosensitive layer on the insulating base layer and the conductive pattern;
• a third exposure step of disposing a third photomask so as to expose, to light, a portion of the first photosensitive layer where the insulating cover layer including the insertion portion is to be formed, and shield, from light, a portion of the first photosensitive layer where the insulating cover layer is not to be formed, and performing exposure;
• a second-photosensitive-layer forming step of forming a second photosensitive layer on the first photosensitive layer after the third exposure step;
• a fourth exposure step of disposing a fourth photomask so as to expose, to light, a portion of the second photosensitive layer corresponding to the insertion portion, and shield, from light, the other portion of the second photosensitive layer, and performing exposure;
• a development step of developing the first photosensitive layer exposed to light by the third exposure step and the second photosensitive layer exposed to light by the fourth exposure step to pattern the first photosensitive layer and the second photosensitive layer such that a total thickness of the first photosensitive layer and the second photosensitive layer in the insertion portion is larger than a total thickness of the first photosensitive layer and the second photosensitive layer in a portion other than the insertion portion;
• and
• a curing step of curing each of the first photosensitive layer and the second photosensitive layer after the development step.