Circuit board and manufacturing method thereof

A method of manufacturing a circuit board, comprising:

• providing a first sacrificial layer and a conductive layer, wherein the first sacrificial layer is located on the conductive layer;
• patterning the first sacrificial layer to form a plurality of first trenches;
• forming a plurality of conductive portions in the first trenches;
• after the conductive portions are formed, patterning the conductive layer to form a plurality of pads;
• after the pads are formed, laminating a build-up structure on the pads and patterning the build-up structure to form a plurality of second trenches;
• forming a plurality of wiring structures in the second trenches;
• after the wiring structures are formed, removing the first sacrificial layer to expose a sidewall of each of the conductive portions;
• after the first sacrificial layer is removed, forming a plurality of outer portions surrounding the conductive portions, respectively, to form a plurality of flexible parts;
• forming a second sacrificial layer to surround the flexible parts;
• forming a plurality of first magnetic attraction parts corresponding to the flexible parts, respectively, and a third magnetic attraction part located on the second sacrificial layer;
• forming a first memory metal layer on the second sacrificial layer to surround the first magnetic attraction parts and the third magnetic attraction part;
• after the first memory metal layer is formed, removing the second sacrificial layer to form a gap;
• providing an initial connecting layer and a second initial memory metal layer, wherein the initial connecting layer is located on the second initial memory metal layer;
• patterning the initial connecting layer and the second initial memory metal layer to form a connecting layer and a second memory metal layer, wherein the connecting layer has a plurality of grooves and the second memory metal layer has a plurality of openings;
• forming a plurality of second magnetic attraction parts and a fourth magnetic attraction part in the openings;
• after the second magnetic attraction parts and the fourth magnetic attraction part are formed, adhering an electronic component to the connecting layer;
• and
• after the electronic component is adhered to the connecting layer, disposing the second memory metal layer on the first memory metal layer to make the first magnetic attraction parts and the second magnetic attraction parts become attracted to each other and be in contact with each other, and the third magnetic attraction part and the fourth magnetic attraction part become attracted to each other and be in contact with each other.