NOVELTY - The unit (145) has two antennas (114) including incoming portions (140) and respective sub-antennas (150, 160) divided from the respective incoming portions, where the incoming portions constitute a coaxial line (142). A space between the incoming portions is filled with an insulator (144) e.g. resin. A set of flow paths for a refrigerant is formed in the insulator. The insulator is in contact with one of the incoming portions and a surface of the incoming portions constitutes a portion of one of the flow paths, where the insulator is spaced apart from the incoming portions.    USE - Antenna unit for use in a substrate processing apparatus (claimed) i.e. inductively coupled plasma (ICP) type substrate processing apparatus used for a reactive ion etching (RIE) apparatus and a plasma enhanced chemical vapor deposition (PECVD) apparatus, for generating a plasma for fabricating a semiconductor device, a display device and a solar cell using a depositing process and an etching process. Can also be used for a capacitively coupled plasma (CCP) type substrate processing apparatus used for a high density plasma (HDP) etching apparatus and a HDP deposition apparatus.    ADVANTAGE - The antennas are connected to an RF power supply in parallel, and the incoming portions of the antennas are formed as a coaxial line at a center part of a lid, so that the RF power is uniformly applied to the antennas, thus improving uniformity of plasma density. The flow paths are formed to contact with the incoming portions to cool down the incoming portions effectively, and the surface of the incoming portions can constitute the portion of one of the flow paths, thus improving cooling efficiency. The apparatus prevents local non-uniformity of the plasma density due to a strong RF magnetic field adjacent to the RF power supply.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a substrate processing apparatus comprising a chamber.    DESCRIPTION OF DRAWING(S) - The drawing shows a perspective view of an antenna unit for a substrate processing apparatus.    Antennas (114)    Incoming portions (140)    Coaxial line (142)    Insulator (144)    Antenna unit (145)    Sub-antennas (150, 160)