One embodiment relates to an apparatus for vacuum-compatible substrate thermal management. The apparatus includes a load-lock chamber coupled to a vacuum chamber, a light-emitting diode array, and a substrate stage. The load-lock chamber is configured to hold a substrate prior to the substrate being transferred into the vacuum chamber, and a substrate stage is configured to hold the substrate in the vacuum chamber. The light-emitting diode array is configured to warm the substrate while the substrate is in the load-lock chamber. Other features, aspects and embodiments are also disclosed.