A resonance photoionization sputtered neutral mass spectrometry instrument for submicron microarea analysis of ULSI devices

The lateral profile of boron in an actual microdevice was obtained by 3D analysis—using the newly developed resonance photoionization sputtered neutral mass spectrometry (SNMS) instrument—with a detection limit of 1018atoms/cm3. The primary ion beam optical system of the instrument uses a Ga liquid metal ion source. The Ga beam diameter was about 30nm and the ion beam current was about 60pA. The analysis time to get the profile was about 40min. Boron was excited by using one ultraviolet photon (249.7nm) and by one visible photon (563nm), and then it was ionized by an infrared photon (1064nm): the so-called three-color resonance ionization. Lateral diffusion profile of boron in the device after chemical vapor deposition (CVD) including heating the wafer was also obtained. These results mean that this SNMS instrument will enable us to easily determine semiconductor processing conditions.