Patent ID: 7757750

Claim:
A cooling system for removing heat from a heat generating component, comprising: a base comprising a bottom wall and a side wall surrounding the bottom wall, the bottom wall and the side wall cooperatively defining a space receiving working fluid therein; and a heat sink mounted on the base, the heat sink defining an evaporating passage and a condensing passage therein, the two passages being in fluid communication with the space of the base, cooperatively the space and the passages defining a loop for circulating the working fluid therein, the working fluid receiving heat and becoming vapor in the space, the vapor flowing first to the evaporating passage and then condensing into liquid when flowing from the evaporating passage to the condensing passage, the liquid then flowing from the condensing passage back to the space; wherein a wick structure is received in the space of the base; wherein the base defines an opening therein, and a heat spreader arranged on the base has a contacting portion extending through the opening for thermally attaching to the heat generating component; and wherein the bottom wall of the base comprises a central portion on which the spreader is mounted, and a peripheral portion, the peripheral portion being higher than the central portion and thus making a step-shape.