Hitachi S-9260A CD Measurement SEM for Sale

Excellent complete and fully operational condition prior to professional dismantling by Hitachi engineers.

The Hitachi S9260. A CD-SEM system designed for the 100 nm process node.  
OVERVIEW: With the semiconductor device manufacturing industry moving to the 100-nm node era, CD-SEMs (critical-dimension scanning electron microscopes) need to have further improved CD measurement reproducibility as well as observation performance. In addition, the demand is growing for functionalities applicable to new fabrication processes, such as ArF-resist and low-k insulating-layer processes, which have been developed to achieve higher levels of integration into microstructures. The Hitachi Model S-9260 CD-SEM system has been developed to meet the requirements of these new fabrication processes. Having the following features, it can provide a CD measurement environment suitable for fabricating next-generation semiconductor devices:
(1) Excellent observation performance based on the electron optical design common in the S-9000 Series,
(2) Enhanced CD measurement reproducibility, throughput, and other basic performance capabilities,
(3) Improved process-variation monitoring,
(4) Instrument performance maintenance/control support functions, and
(5) New process application functions such as those for beam-tilt observations, surface- charged-specimen measurements, and ArF-resist measurements.  

INTRODUCTION
IN AROUND 1985, mass production of 1-Mbit DRAM (dynamic random access memory) devices based on a 1.3-μm design rule started in the semiconductor device manufacturing industry. Since then, to inspect pattern dimensions, CD-SEMs using electron-beam technologies have been adopted in lieu of optical microscopes. As a CD-SEM can measure the ultrafine patterns formed in semiconductor-fabrication processes, it enables producing high-quality semiconductor devices. At present, semiconductor devices are mass- produced based on a 0.13-μm design rule for higher integration density. In the near future, the design rule in mass production of microchips will be 0.1 μm or less. According to the recent International Technology Roadmap for Semiconductors (ITRS) report, introducing technical trends in semiconductor- fabrication processes, the market needs for CD-SEM systems can be enumerated as below: (1) Observation of high-aspect-ratio patterns and high- accuracy stable measurement in a short time. (2) Application to fabrication processes based on a 0.1- μm design rule or less. (3) Detection of variations in fabrication processes by measuring pattern-configuration variations. (4) Unsupervised automatic operation to increase productivity. Presented here is a new CD-SEM S-9260 1) model that has been developed to meet the market needs mentioned above. The future prospects of CD-SEM systems will also be discussed in this paper.  

FEATURES OF MODEL S-9260 CD-SEM
Excellent Observation Performance
The electron optical system of the Model S-9260 CD-SEM has a 3-nm image resolution, which is applicable to lines/spaces and hole patterns of less than 0.1 μm.   
CD measurement reproducibility
The CD measurement reproducibility has been enhanced by reducing specimen contamination; a vacuum specimen chamber ensures higher cleanliness and the pattern detectability in the image recognition has been improved. In CD measurements that are repeated ten times, a 2-nm reproducibility value can be achieved (3-sigma standard deviation).
Enhanced throughput
A new type of transfer robot mechanism is used to shorten the wafer-handling time in atmospheric air. Furthermore, a high-speed image processor and an image-processing algorithm have been developed to achieve a 65-wph (wafers per hour) throughput (in 5- point measurements on Hitachi standard wafer specimens).
Process-variation Monitoring
Early detection of process variations is essential for production yield control, thus CD-SEM systems should also contain this function. The Model S-9260 has formula-editor and beam-tilt observation functions that enable detecting process variations early and controlling them easily.
Formula-editor function
The formula-editor function allows users to measure plural dimensional values of an object pattern under test and to monitor variations in configuration of the object pattern arithmetically by using the measured dimensional values.Arbitrary calculations can be defined for values such as the line-pattern bottom width, top-bottom width ratio, left and right inclination dimensions, and the inclination angle. Using calculation values that are optimal for an object pattern enables effectively detecting variations in the pattern configuration. In pattern recognition, the ratio of top to bottom (T/B) is more responsive than the width of bottom, and hence the former is more useful for detecting process variations.  
Beam-tilt observation function Wafer-charge-correcting function
The beam-tilt-observation function is designed to deflect the primary electron beam to a microstructure pattern so the user can inspect the configurations of the side walls and the regions near the hole bottoms on the pattern, which would otherwise be difficult to observe. In the Model S-9260, the primary electron beam can be tilted in eight directions. The process variation data attained with the functions mentioned above is applicable to APC (advanced process control) for semiconductor- fabrication facilities such as pattern-exposure equipment. Thus, process variations can be reduced more efficiently.  
Instrument-performance Maintenance/Control- support Function
The Model S-9260 is provided with an optical- performance-monitor function that enables the user to check the current condition of the optical mechanisms. With this function, the user can judge the axial adjustment timing. The Model S-9260 also has an automatic alignment function for enabling electrical axial adjustment, which will improve self- diagnostic testability and maintainability.  
Optical-performance-monitor function
The optical-performance-monitor function is incorporated in the Model S-9260 for overall monitoring in axial-adjustment and astigmatism- correction errors. The dimensional value calibration specimen “microscale” unique to Hitachi is available as the standard reference. The microscale is a reference device on which a line-space pattern is formed with an accurate pitch (240 nm) by laser interference fringe exposure and silicon monocrystal isotropic etching. The X- and Y-direction images of the microscale are Fourier-transformed to evaluate the image quality. The calculated value is indicated as a ratio to pre-recorded standard image data. The time-course variation can also be controlled by using a time-series graph.
Automatic alignment of electron optics
Conventionally, users need to manually adjust axially the electron optics at regular intervals or whenever the image quality degrades. The Model S- 9260 is equipped with an automatic alignment function based on image processing, so it can perform operator- independent accurate axial adjustment in a short time.  
Wafer-charge-correcting function
Various wiring materials, including low-k materials, and several fabrication processes have been used in recent years, so as a result wafer surfaces have become more likely to be charged. In some cases, charging at 200 to 300 V can cause problems, such as unsuccessful automatic focusing and CD measurement errors, due to unintentional changes in the objective lens’ optical magnification. To prevent these problems, the Model S-9620 is provided with a wafer-charge-correcting function 2) . Using an electrostatic probe mounted on the wafer- transfer path, the amount of surface charge is measured during the wafer-transfer operation, and the voltage corresponding to the surface charge is superimposed on a retarding voltage. This way the wafer-surface charge can be corrected without causing an adverse effect on the throughput.  
ArF resist application package
An ArF resist intended for lithography with ArF light at a 193-nm wavelength that is produced by using acrylic resin as a base material is excellent in resolution but problematic in SEM/etching resistance. During an observation the ArF resist noted above is likely to shrink due to electron-beam exposure. Since the degree of shrinkage of the ArF resist depends on the energy and dose of the electron-beam exposure, they should be minimized to suppress the shrinkage.  

Other Features
In addition to the foregoing, the Model S-9260 has a variety of new functions.
A multi-focus function, for example, facilitates observing specimens that have a large step difference. Here, in-focus areas only are taken from multiple images that have different focal point positions, and the image is synthesized selectively . Thus, the multi-focus function enables high-magnification observations of the entire visual field of a specimen that has a step difference exceeding 10 μm.  

CONCLUSIONS
In semiconductor-device fabrication based on a 0.1- μm design rule or less, CD-SEM systems need to measure finer patterns highly accurately at a high speed and the systems need to be applicable to new kinds of materials and processes. The Model S-9260 CD-SEM system described above is an advanced instrument that has features that meet the requirements for fabricating next-generation semiconductor devices based on a 0.1-μm design rule or less.  
Measurement repeatability: (static) 2 nm (3 sigma)
• Acceleration voltage 300 – 1,600 kV
• Resolution 3 nm  
• Throughput 65 wafers/h
• MAM time Less than 5 s
• Open type 3 cassette port