A process for manufacturing phase change memory cells includes the step of forming a heater element in a semiconductor wafer and a storage region of a phase change material on and in contact with the heater element. In order to form the heater element and the phase change storage region a heater structure is first formed and a phase change layer is deposited on and in contact with the heater structure. Then, the phase change layer and the heater structure are defined by subsequent self-aligned etch steps.