A 3D package for semiconductor thermal management can include a 3D submount forming a mechanical block including at least one embedded channel formed within the mechanical block and configured to accept cooling liquid therethrough, a first tubular connection for providing cooling liquid to the at least one embedded channel, and a second tubular connection for removing cooling liquid from the at least one embedded channel. Integrated slots can be provided for accepting and mounting semiconductor components. Mounting holes can be formed in the mechanical block for securing optical elements. At least one semiconductor laser array die can be secured to the mechanical block at the integrated slots, wherein the at least one semiconductor laser array die is kept cool by the cooling liquid flowing through the at least one embedded channel.