A light, compact, non-bottom panel type cooler module includes a plurality of radiation fins arranged in a stack, and a plurality of U-shaped heat pipes fastened to the radiation fins to hold the radiation fins in parallel, each U-shaped heat pipe having one or two opposite end pipe sections thereof press-fitted into respective through holes on the radiation fins and a flat bottom surface portion exposed to the outside of the radiation fins for bonding to a semiconductor device for enabling the heat pipes to transport heat from the semiconductor device to the radiation fins for dissipation.