Demonstration of parallel scanning probe microscope for high throughput metrology and inspection

Abstract

With the device dimensions moving towards the 1X node and below, the semiconductor industry is rapidly approaching the point where existing metrology, inspection and review tools face huge challenges in terms of resolution, the ability to resolve 3D and the throughput. Due to the advantages of sub-nanometer resolution and the ability of true 3D scanning, scanning probe microscope (SPM) and specifically atomic force microscope (AFM) are considered as alternative technologies for CD-metrology, defect inspection and review of 1X node and below. In order to meet the increasing demand for resolution and throughput of CD-metrology, defect inspection and review, TNO has previously introduced the parallel SPM concept, consisting of parallel operation of many miniaturized SPMs on a 300 and 450 mm wafer. In this paper we will present the proof of principle of the parallelization for metrology and inspection. To give an indication of the system's specifications, the throughput of scanning is 4500 sites per hour, each within an area of 1 µm 2 and 1024 ×1024 pixels.

A miniaturized, high frequency mechanical scanner for high speed atomic force microscope using suspension on dynamically determined points

“…Recently, we have introduced an architecture for a parallel high throughput AFM, 3,5 which consists of parallel operation of many miniaturized AFM on a large area sample such as semiconductor wafers or optical lithography masks. In order to eliminate the crosstalk, we have opted for a combined tip and sample scanning architecture, where the xy-scanner only moves the sample horizontally and the z-scanner moves the tip in order to follow the topography.…”

“…The scan head can be placed on a table and is mechanically decoupled from the arm that is used to automatically place the head at the desired location. 5 The sample is placed above the scan head onto a scanning stage which performs scanning in the horizontal plane.…”

“…The increase of the imaging speed in atomic force microscopy (AFM) is of interest in several practical applications, including wafer inspection in semiconductor applications [1][2][3][4][5] and visualizing dynamic behavior of proteins in a physiological environment. 6,7 The imaging speed of AFM is determined by the slowest component in the system (cantilever time response, 8,9 bandwidth of cantilever read-out, 10,11 controller bandwidth, 12 and mechanical scanner bandwidth [13][14][15] ).…”

Automated Cantilever Exchange and Optical Alignment for High-Throughput Parallel Atomic Force Microscopy

“…The motion of the cantilever is measured using optical beam deflection (OBD), 1 which is converted to a topography measurement of the surface. 2,3 Due to its atomic resolution and the ability to measure mechanical, 4 physical 5 and chemical 6 parameters, AFM has attracted great interest in several industrial applications, such as semiconductor metrology, 7,8 biological and medical applications, 5 material science 9 and data storage. 10 Industrial applications with high-volume manufacturing characteristics require high-throughput, fully automated instruments.…”

“…The instrument for this procedure is specifically designed for use in the recently developed parallel AFM. 2,7,16 The automatic cantilever exchange and alignment instrument is capable of exchanging 22 cantilevers in parallel in only 6 seconds and includes OBD alignment for a high signal-to-noise ratio (SNR). No intermediate holder is used, maximizing the performance of the z-scanner and rendering the method compatible with any type of AFM cantilever.…”