A rewiring technique for integrated circuit operation analysis using a silicon oxide film deposited by a focused ion beam

The silicon oxide deposition technique with a Si focused ion beam was applied to rewiring from the first aluminum line below a wide power line in a 256k CMOS SRAM. The widths of the power line and the first aluminum line were 130 and 1.5 μm, respectively. First, the layer on the first aluminum line was etched for an area of 4.5×4.5 μm by a Ga focused ion beam. Second, silicon oxide was deposited into the hole using a 60‐keV Si²⁺ focused ion beam with a mixed gas of tetramethoxysilane and oxygen, then, the deposited silicon oxide film was etched for an area of 2×2 μm down to the first aluminum line by the Ga focused ion beam. Last, tungsten was deposited for rewiring from the first aluminum line using the conventional focused ion beam method. The leak current measured between the deposited tungsten and the power line was 1×10^-8 A at 5 V which is sufficiently small for operation analyses of semiconductor devices.