Heat exchanger

A heat exchanger, comprising:

• a first case, comprising a first plate structure and a first protruding structure, wherein the first plate structure comprises a first inner surface, the first protruding structure protrudes from the first inner surface, and a longitudinal axis of the first protruding structure is extended from a top side to a bottom side of the first case;
• a second case, comprising a second plate structure and a second protruding structure, wherein the second plate structure comprises a second inner surface, the second protruding structure protrudes from the second inner surface, and a longitudinal axis of the second protruding structure is extended from a top side to a bottom side of the second case;
• a substrate, disposed between the first case and the second case and corresponding to the first protruding structure and the second protruding structure;
• an engaging structure, wherein the substrate is engaged with the first inner surface, the first protruding structure, the second inner surface, and the second protruding structure via the engaging structure, and the substrate is in contact with at least three different lateral surfaces of the engaging structure so that the substrate and the first case combine are bonded;
• an evaporator, disposed on the substrate and having a first inlet structure and a first outlet structure;
• a condenser, disposed on the substrate and having a second inlet structure and a second outlet structure, wherein the substrate is disposed between the evaporator and the condenser;
• a first tube, connected to the first inlet structure and the second outlet structure;
• and
• a second tube, connected to the first outlet structure and the second inlet structure.