Method for manufacturing rigid-flexible circuit board

A method for manufacturing rigid-flexible circuit board comprising:

• providing an adhesive sheet defining at least one first opening, a copper foil, and a flexible board, the flexible board comprising a mounting region and a folding region connected to each other;
• pressing a removable sheet on a pressed surface of the adhesive sheet corresponding to each of the at least one first opening, to cause each removable sheet to cover each of the at least one first opening;
• pressing the copper foil, the adhesive sheet with the removable sheet, and the flexible board in that sequence;
• wherein the removable sheet corresponds to the folding region, and is embedded in the adhesive sheet;
• the copper foil contacts with the pressed surface and the removable sheet;
• an area of the adhesive sheet contacting with the removable sheet concaves to form a step, and the adhesive sheet is softened and flows from the step to a center of the first opening to form an extending portion;
• an interspace is formed between the removable sheet and the flexible board;
• forming an outer conductive layer on the copper foil, thereby the outer conductive layer, the adhesive sheet with the removable sheet, and the flexible board forming a middle structure;
• and
• removing a removing region of the outer conductive layer corresponding to the folding region and the removable sheet from the middle structure, thereby defining at least one second opening to expose the folding region and the step, and obtaining the rigid-flexible circuit board.