The present invention relates to a substrate treating apparatus for depositing a phase-change layer of a phase change memory (PRAM), and to a method for treating a substrate, and more particularly, to an apparatus and method for treating a substrate for the manufacture of a phase-change layer having superior deposition characteristics. The method for treating a substrate for the manufacture of a phase-change memory includes: a step of forming a lower electrode on a substrate on which patterns are formed; a surface-treating step of removing impurities generated during the step of forming the lower electrode and remaining on the surface of the substrate; a step of nitriding the substrate from which the impurities have been removed; and a step of sequentially depositing a phase-change layer and an upper electrode on the lower electrode. Further, the apparatus for treating a substrate includes: a load lock chamber into/from which a plurality of substrates are loaded or unloaded, wherein the inside of the load lock chamber is converted from an atmospheric state to a vacuum state; a vacuum transfer chamber including a substrate transfer robot for transferring a substrate, wherein the inside of the vacuum transfer chamber is maintained in the vacuum state and has a polygonal shape, and one surface from among the plurality of surfaces of the vacuum transfer chamber is coupled to the load lock chamber; a nitriding chamber coupled to one surface of the plurality of surfaces of the vacuum transfer chamber so as to nitride the substrate on which the lower electrode is disposed; and a process chamber coupled to one surface from among the plurality of surfaces of the vacuum transfer chamber in order to deposit a phase-change layer on the substrate of the substrate nitrided in the nitriding chamber.