To keep up with Moore’s law, the semiconductor industry continues to push the envelope in developing new device architectures containing novel materials. This in turn pushes the need for new solid-state analytical capabilities, whether for materials characterization or inline metrology. Aside from basic R&D, these capabilities are established at critical points of the semiconductor device manufacturing line, to measure, for example, the thickness and composition of a thin film, dopant profiles of transistor’s source/drain regions, the nature of defects on a wafer’s surface, etc. This approach is used to reduce “time to data”.
Imec supports and drives the development and implementation of tomorrows materials characterization techniques. This is accomplished through a careful balance between service work and fundamental research in the areas of:
Raman Spectroscopy and the related technique of Photo Luminescence (PL)
Analytical techniques for understanding the local chemistry, composition, and in some cases the strain, within solid materials under ambient conditions. Although analysis is typically applied over micron scale dimensions, array profiling allow for confined volume analysis, with significant enhancement effects noted when plasmonic effects come into effect.
Rutherford Backscattering (RBS) and related techniques of Elastic Recoil Detection (ERD) and Proton Induced X-ray Emission (PIXE)
Analytical techniques for defining the elemental composition within solid materials under UHV conditions, but without the requirement for reference samples. Although analysis is restricted to relative large areas (mm is common), RBS is experiencing a renaissance due to improvements in resolution (energy → depth) and array profiling capabilities being implemented within MCA.
Scanning Probe Microscopy (SPM) inclusive of Atomic Force Microscopy (AFM), various electrical and physical variants thereof, as well as Scanning Tunneling Microscopy (STM)
Analytical techniques for measuring the surface topography and/or electrical properties (conductivity, resistance, work-function, etc.) and/or mechanical properties (friction, modulus, etc.) of solid surfaces. These techniques are capable of nm scale spatial resolution over areas up to micron scale dimensions whether under atmosphere or high vacuum. One example of an MCA concept to product cycle concerns the SSRM-FFT box for reducing parasitic resistance.
Secondary Ion Mass Spectrometry (SIMS)
An analytical technique used to understand the elemental composition and distribution from solid surfaces to unparalleled detection limits (ppb levels) under UHV conditions. Deeper layers can be accessed through sputtering. Although analysis is generally applied to areas of the order of 100 x 100 microns, array profiling (1.5D SIMS and SF-SIMS protocols developed within MCA) allow for confined volume analysis. Molecular distributions can also be examined.
Transmission Electron Microscopy (TEM)
Analytical techniques for defining dimensions of solid structures to unparalleled spatial resolution (sub atomic dimensions) under UHV conditions. Combining with EDX and EELS allows for nm scale elemental mapping. Tomography allows for nm scale 3D visualization of contrast (Z) and elemental distributions (EDX). NBD allows for nm scale strain analysis. Missing wedge effect removal protocols are under evaluation within MCA.
X-ray Photoelectron Spectroscopy (XPS)
An analytical technique for measuring the composition (atomic) and speciation of elements present in the outer 10 nm of solid surfaces under UHV conditions. Deeper layers can be accessed through sputtering. All elements from Li-U are detectable if above 0.1 atomic %. Although restricted to relative large area analysis (micron scale), array profiling and the use of higher energy sources are areas of interest within MCA.
On the cover of PSS
The MCA team encompasses every level of expertise as needed to support end to end solutions for the imec fab and CMOS industry in general. Some examples include (and there are many more)
- The deployment of novel SPM capabilities to support MX2 R&D
- The implementation of the SF-SIMS approach for array profiling
- The transfer of M4PP and the ETM suite to the fab environment
- The development of high resolution RBS and RBS array profiling capabilities
- The examination of enhancement effects noted in Raman when applied to confined volume analysis