A new focused-ion-beam (FIB) micro(μ)-sampling technique has recently been developed to facilitate transmission electron microscope (TEM) specimen preparation, while allowing chips or wafer samples to remain intact. A deep trench is FIB-milled to dig out a small, wedge-shaped portion of the sample (or a microwedge) from the samples area of interest, leaving a small, brige-shaped portion (or a microbridge) to support the microwedge. A metal needle is then manipulated into position for lifting the microwedge, i.e., the μ-sample. FIB-assisted deposition (AD) is used to bond the needle to the μ-sample. FIB-milling of the microbridge then separates the μ-sample from the chip or wafer. The separated μ-sample is mounted onto a TEM grid and secured using FIB-AD. The μ-sample is then FIB-thinned further, to a strip of about 0.1 μm thick. All of the above steps are accomplished under vacuum in the FIB system. This design permits a reliable and user-friendly environment for TEM specimen preparation, while keeping chips or wafer samples intact. It also permits operators to repeat TEM inspection and FIB-milling so that precise areas of interest may be made available for TEM inspection. Both cross-sectional and plan view TEM μ-sampling are feasible.
A coaxial microwave ion source which provides high-current ion beams is presented. The microwave discharge takes place in a magnetic mirror field. The intensity of this field is higher than that of the electron cyclotron resonance at 2.45 GHz over the entire discharge region. The antenna of the discharge chamber is water cooled to protect the ceramic which is used as the vacuum seal as well as the conduit for microwaves into the discharge chamber. The ion beam is extracted through a three-stage multiaperture lens with 124 holes 3 mm in diameter. An electron suppressed Faraday cup is used to collect 200-mA argon and 400-mA hydrogen ion beams.
A long-life, high-current, microwave ion source for an electromagnetic mass separator is described. Ionization takes place due to the 2.45-GHz microwave discharge at a magnetic field intensity which is higher than the electron cyclotron resonance magnetic field. The discharge chamber is a ridged circular waveguide. The discharge region is restricted to a rectangular volume between the ridged electrodes by filling the remaining portions with dielectric. This source operates under low pressure (10(-2)-10(-3) Torr) and with high power efficiency. The incident microwave power is only several hundred watts at maximum output. When PH(3) gas is introduced, the total extracted current is about 40 mA with a 2x40-mm extraction slit. A P(+) ion implantation current of more than 10 mA is obtained by combining the source with a 40-cm radius, 60 degrees deflection magnetic mass separator.
Low voltage (30 kV) field emission scanning transmission electron microscopy (FE-STEM) has been employed in the characterization of state-of-the-art semiconductor static random access memory (SRAM) using specimens prepared at several different thicknesses (70-180 nm). A focused ion beam (FIB) system, a FIB-SEM compatible specimen holder and an in-lens FE-SEM have been employed for alternating between FIB milling and SEM/ STEM imaging. As a result, ion implanted atom damage during manufacturing, grains in aluminium interconnects, poly silicon gates, thin metal barriers and a thin gate oxide layer were observed by low voltage FE-STEM. STEM, in-lens FESEM, FIB
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