Semiconductors: Metrology | FIB | Nanomaterials
Chemical mechanical planarization (CMP) is a process widely used within the microelectronics industry to create atomically flat surfaces. The process uses a slurry of abrasive particles containing a corrosive chemical to selectively remove irregular topography. CMP is used with different materials at different levels within the chip. It is the preferred planarization step used for Cu, Cu barrier (Ta/TaN), W, inter-layer dielectrics (ILD), shallow-trench isolation (STI), polysilicon, and pre-metal dielectric (PMD) layers.
The design of nanostructured materials like CMP slurries on an industrial scale requires the control of disperse systems of nanoparticles as well as of single isolated "bad" particles . It is well known that slurry abnormalities resulting from large abrasive particles and abrasive particle agglomerations can cause defects on wafer surfaces during CMP so quality control is of extreme importance. Particle-particle interactions generate secondary nanometer structures, clusters or agglomerates, which can dominate the relevant properties of the bulk material. Characterization of these slurries is a significant challenge. The dilution of the slurries for use with TEM or AFM has typically been shown to distort the interparticle forces and generate artifacts. However, the use of Smart Grids offers an opportunity to capture the particles and aggregates from the slurry directly through the use of tailored surface chemistry. Smart Grids can have application for both manufacturers and consumers of CMP slurries to enhance quality control. Please contact Dune Sciences to discuss your characterization needs specific to your formulation of CMP slurry.