Hi-K Metal Gate (HKMG) with JVX7300HR

Jordan Valley offers a metrology solution using x-ray reflectometry (XRR) for monitoring the metal gate deposition process. The layers thicknesses of the HKMG stack are critical parameters for transistor performance and in-line monitoring is necessary. XRR is an attractive alternative to the more traditional optical metrology used to control HKMG processes. XRR provides both accurate and precise (GR&R capable) thickness measurement of single and multiple layers, whilst providing additional information on layer density and interface roughness. It is a first-principles technique, therefore does not require any calibration, and can be used to measure films that are both optically opaque and transparent. XRR does not require the creation of complicated optical models that are dependent on uncertain material properties, such as optical n & k parameters. This offers a distinct ease-of-use advantage especially when a process is not stable during development. The JVX7300HR tool provides fast and production worthy solutions for HKMG pattern wafer metrology.

The FastXRR approach provides an unrivalled number of parameters in a single measurement (individual thickness, density, and roughness of each metal layer) and a beam footprint suitable for scribe-line measurements on product wafers. The JVX series of tools are production proven with demonstrated fleet matching capabilities.

XRR results of dynamic measurements with sub-Angstrom precision. Tri layer metal gate, scribe-line measurement

49-site wafer thickness maps. Process variation is distinguished

49-site wafer density maps. Process variation is distinguished

X-ray diffraction imaging (XRDI), which is also known as X-ray topography, is a technique that images crystalline defects in single crystal materials, such as dislocation, slip, precipitates and micro-cracks. The diffracted intensity is imaged with micron resolution; defects that introduce strain or tilt into the crystal lattice will diffract more strongly than the surrounding perfect material leading to changes in intensity in the image. In a transmission geometry, XRDI can image buried defects that are not imaged by traditional optical techniques that only image the surface of the wafer. Defects in thin epilayers can also be imaged using a reflection geometry.

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Within the Si industry, a large issue is the breakage of wafers during processing. BedeScan can image wafers even through to metal deposition to monitor edge defects, chipping and other damage which may cause wafer failure during further processing.

It is possible to scan a full wafers or smaller areas to identify regions of interest. If the likely location of defects are known, then smaller regions can be identified and scanned (for example, edge only).

Once the full wafer is surveyed then detailed investigation at ultra-high resolution can be performed, as shown below.

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The technique can be applied to any single crystal substrate, and is often used to identify substrate defect issues.

A typical BedeScan application is the characterization of SiC substrate quality and subsequent GaN growth. Shown below are SiC images in reflection mode, with the same sample after GaN deposition. Notice how the defects replicate from the substrate to the layer.

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The D1 topography attachment allows reflection mode XRDI images to be collected on a D1 system. This is an ideal attachment to the standard D1 tool to enhance the versatility of the system.

NiSi, CoSi, WSi

The thickness measurement of silicided films is a metrology challenge, due to the complexity of the metal and silicon reactions. It can lead either to non-homogeneous layers with incomplete phase transformation, or to complete silicidation that gives rise to significant surface roughness. Nickel Silicide (NiSi) is emerging as the choice material for contacting the transistors for the 65nm technology node and beyond. Jordan Valley's fast XRR technology gives thickness, density and roughness information of silicided films to control this critical front end of line process.

Variation of the density of the top Ni2Si layer after spike annealing at temperatures between 310°C and 450°C (top right). Schematic drawing of the cross-section of the nickel silicide film showing the occurrence of the Ni2Si and NiSi phases at different annealing temperatures (bottom right).

By measuring the silicide's density using the JVX series of systems, the anneal process can be optimized to achieve the desired silicide formation.

NiSi thicknesses can be quite different in n and p channels at the same anneal temperatures.

At low and high end of anneal temperatures, they react similarly. However, at intermediate temperatures, the thicknesses of NiSi in different channels can be quite different.

With the JVX XRR channel, the thickness and density of the Ni and NiSi layers can be measured to control the silicidation process.

SiGe, Si:C, sSOI

The JVX7200 provides is a state-of-the-art capabilities for advanced strain engineering applications for the 32 nm, and beyond, technology nodes.

Jordan Valley's Fast HRXRD technology quantitatively measures the critical parameters of strain, thickness, composition and lattice relaxation of epitaxial layers with unsurpassed precision and speed and is capable of measuring product wafers in-line.

FastHRXRD scan around the 004 Bragg diffraction peak of a nominally 500 Å Si(1-x)Ge(x) layer with x = 20.0% grown on a bulk Si(011) substrate.

Conventional HRXRD scan around the Si(004) peak of a 963 Å Si(1-x)C(x) layer with x = 0.98% grown on a Silicon (001) substrate. Epitaxial Si(1-x)C(x) is being investigated for use in selective source/drain areas, enhancing carrier mobility in 32nm and beyond NMOS transistors.