Abstract: A wafer holding apparatus includes an electrostatic chuck configured to clamp an object, a baseplate made of aluminum and configured to support the electrostatic chuck, a water pathway portion disposed in contact with or inside the baseplate and made of a metal having higher corrosion resistance than aluminum, and a water pathway disposed inside the water pathway portion and having an entire wall surface thereof constituted by the water pathway portion, wherein the baseplate and the water pathway portion are directly bonded to each other.

Abstract: A trap apparatus includes: a first cylindrical member including a space; a second cylindrical member removably disposed in the space and including side opening which allows a gas stream to flow in therethrough, and a downstream side opening which allows the gas stream flowing in from the upstream side opening to flow out therethrough; a downstream side trap member which is disposed inside the second cylindrical member to block the downstream side opening; and an upstream side trap member which is disposed between the downstream side trap member and the upstream side opening of the second cylindrical member and includes a concave portion recessed in a direction approaching the downstream side trap member.