Circuit board

A circuit board, comprising:

• a main board, comprising:
• a first external structure;
• a second external structure;
• and
• an internal structure disposed between the first external structure and the second external structure, wherein the internal structure, the first external structure, and the second external structure are stacked along a first direction,
• wherein the internal structure includes:
• a first internal circuit layer;
• a second internal circuit layer;
• and
• an insulating layer disposed between the first internal circuit layer and the second internal circuit layer, wherein the insulating layer, the first internal circuit layer, and the second internal circuit layer are stacked along the first direction;
• a first bonding layer disposed between the internal structure and the first external structure, wherein the first bonding layer connects to the internal structure and the first external structure;
• a second bonding layer disposed between the internal structure and the second external structure, wherein the second bonding layer connects to the internal structure and the second external structure;
• a thermistor layer embedded in the first bonding layer and disposed on the insulating layer and the first internal circuit layer, wherein the thermistor layer directly contacts the insulating layer;
• a plurality of N-type semiconductor units and a plurality of P-type semiconductor units, wherein the N-type semiconductor units and the P-type semiconductor units are embedded in the second bonding layer and electrically connect to the second internal circuit layer and the second external structure, wherein the N-type semiconductor units and the P-type semiconductor units alternately arrange along a second direction perpendicular to the first direction, and an orthogonal projection of the N-type semiconductor units and the P-type semiconductor units on the insulating layer overlaps an orthogonal projection of the thermistor layer on the insulating layer;
• a first thermal conductive layer disposed on the thermistor layer;
• and
• a second thermal conductive layer disposed on the second external structure,
• wherein the second thermal conductive layer directly contacts the second external structure and the second bonding layer.