Semi-flex printed circuit board with cover-opening opening

A semi-flex printed circuit board with cover-opening opening, comprising:

• a core substrate with an inner side surrounding a cover-opening opening, the cover-opening opening penetrating through an upper surface and a lower surface of the core substrate;
• two metal dam structures arranged on the lower surface of the core substrate at two opposite sides of the cover-opening opening respectively and surrounding the cover-opening opening together with the core substrate;
• a bonding sheet attached to the lower surface of the core substrate with the two metal dam structures provided thereon, a part of the bonding sheet being exposed to the cover-opening opening and surrounding the cover-opening opening together with the core substrate;
• and
• a core board arranged on a side surface of the bonding sheet away from the core substrate,
• wherein two sides of a bottom of the core substrate surrounding the cover-opening opening are provided with two laser cutting sidewalls respectively, and sidewalls of the two metal dam structures surrounding the cover-opening opening are connected with the two laser cutting sidewalls respectively and each defined as metal dam sidewall, and wherein in relation to each of the metal dam sidewalls and the laser cutting sidewall connected thereto, an included angle between the metal dam sidewall and the laser cutting sidewall is 120 degrees to 150 degrees,
• wherein a side surface of the bonding sheet facing to the core substrate is attached to the two metal dam structures on the core substrate with a portion of the bonding sheet further filled in a gap at inner sides of the two metal dam structures so as to be attached to the lower surface of the core substrate, and the side surface of the bonding sheet away from the core substrate is attached to the core board so as to attach the core substrate with the core board.