In one embodiment of the invention, there is provided a tool for annealing a magnetic stack. The tool includes a housing defining a heating chamber; a holding mechanism to hold at least one wafer in a single line within the heating chamber, a heating mechanism to heat the at least one wafer; and a magnetic field generator to generate a magnetic field whole field lines pass through the single line of wafers during a magnetic annealing process; wherein the holding mechanism comprises a wafer support of holding the single line of wafers between the heating mechanism and the magnetic field generator.