High-speed Pattern Research Articles

Nanometer Lithography for Quantum Scale Devices

ABSTRACTElectron-beam lithography that has the capability of writing high-resolution nanometer features in semiconductors will be required to fabricate next-generation quantum scale devices, such as nanometer gate mini-FET's, lateral quantum-well arrays, or metal grid radiators,which have feature sizes from 100 nm (1000 A) to 15 nm (150 A). A Philips EM 420T scanning transmission, electron microscope (STEM) has been modified to write nanometersize features in gallium arsenide. For this STEM we have developed a high-speed beam blanker and pattern generator (PG) that is resist speed limited. The maximum writing field size is 100 by 100 micrometers; within this field size, the smallest addressable step is approximately 1.8 nm (18 A). A HP-9845 is used to supply data for the PG and for computer-aided design of the devices to be written. Pattern transfer from the resist to GaAs is completed by using the liftoff method. As a result of this capability, we have patterned more than one million dots in a prototype 80 by 80 micrometer solid state radiator. The dots have diameters down to 15 nm (150 A), which requires an e-beam writing time of less than 30 minutes.

A lower cost system for VLSI design, layout, DRC, and pattern generation

This paper describes a lower cost, but very powerful, intera interactive graphics system for VLSI design and layout. The system is the first complete single user graphics system suitable for VLSI design and layout; it incorporates a hierarchiacal structure to facilitate high speed design, DRC, and Pattern Generation. This paper is a case study.

Basic Technology for VLSI (Part II)

This paper describes some of the recent work in the field of basic technology at VLSI Cooperative Laboratories. In microfabrication technology, a pair of high-speed electron-beam pattern delineators, electron-beam mask inspection, a pair of electron-beam projection systems, an X-ray lithography system, and electron-beam and X-ray resists are described. Thermally induced microdefects in silicon crystal are analyzed. A plasma etching system, basic testing and evacuation, and basic devices are also discussed.

Basic technology for VLSI (part II)

This paper describes some of the recent work in the field of basic technology at VLSI Cooperative Laboratories. In microfabrication technology, a pair of high-speed electron-beam pattern delineators, electron-beam mask inspection, a pair of electron-beam projection systems, an X-ray lithography system, and electron-beam and X-ray resists are described. Thermally induced microdefects in silicon crystal are analyzed. A plasma etching system, basic testing and evaluation, and basic devices are also discussed.

Control of Large Power Systems Based on Situation Recognition and High Speed Simulation

The operation of large power systems places an increasing importance on the security of the system which must be evaluated in steady state, transient, and long term dynamic situations. A method based on situation and high speed simulation for on-line security computations is proposed and analyzed. The method combines the advantages of high speed hybrid computer simulation and pattern recognition methods, and, at the same time, has the flexibility of a pure digital simulation.

Use of a Microprocessor in Digital Testing

The use of a microprocessor as a controller in digital testing is usually restricted by the relatively low operating speed of the microprocessor. Two different approaches to building a microprocessor-based digital test system are discussed and compared in this paper. It is found that if a high-speed test pattern repetition rate is not a necessary requirement, the semidynamic approach which tests and analyzes the UUT on a real-time basis will result in a faster and simpler configuration.

試行による人工の手の高速運動パターンの形成

試行による人工の手の高速運動パターンの形成

Device Photolithography: The Primary Pattern Generator Introduction

The need for a new, high-speed pattern generator capable of producing the more complex and precise circuit patterns required in the 1970s has already been discussed.1 This paper describes the design and operation of the Primary Pattern Generator (PPG) in some detail. For the convenience of the reader, the paper has been separated into four parts. Part I covers the optical design of the machine, including the considerations which led to the choice of an argon laser light source, a recording emulsion, and an optimum combination of spot size and brightness. The original choice of a mechanically scanned system was made on the premise that, with such an approach, the required accuracy could be built in and retained over many years of operation, and Part II discusses the principal considerations behind this premise. In that paper are discussed the dimensional stability of the structural materials and their use in an extremely stiff structure, the features provided to align the parts of the system to the required tolerances, and the design of drive systems, essentially free from both vibration and wear. The control of the machine to produce the pattern encoded on the input tape is discussed in Part III; Part IV deals with the methods used to align the assembled machine and details the pattern accuracy and reproducibility which was achieved.

An aerial analogue computer. An “instantaneous” radiation pattern tracer and “degign apparatus” for directional arrays

A “first model” of an experimental high-speed analogue computer and pattern tracer for the radiation patterns of two-dimensional arrays (the pattern is traced in less than 1/50 sec) is described and the application of such instruments to the design of arrays with specified required patterns discussed.The design of arrays with a minimum number of separate aerials, which meet given pattern specifications (within specified tolerance limits) is usually a very tedious and cumbersome trial-and-error procedure. In such a situation any suitable computing apparatus is of help by simplifying and reducing the duration of each separate trial. A high-speed computer-tracer has the additional advantage that it enables the designer not only to compute quickly a sequence of trial patterns, but to try to obtain a satisfactory approximation to the required pattern by direct visual curve fitting on the screen of the c.r.o. When a satisfactory pattern has been obtained, the corresponding array (i.e. the positions of the individual aerials and their current amplitudes and phases) is directly and completely determined by the positions of the manual controls of the analogue.The model described is limited to 2-aerial and 3-aerial arrays and the maximum distances of the aerials from a reference point are at present of the order of 1½λ, but these limitations are not inherent in the chosen method of analogue representation, and probably arrays consisting of more than five aerials with maximum distances of more than 3λ could be successfully investigated and designed by means of a computer of the type under discussion.The paper deals with some general array design problems, with the analogue relation used as the basis of the computer and with the detail design of the computer. Special points which are emphasized and discussed in detail are as follows:—1. The “design apparatus” aspect of high-speed computers with instantaneous indication of the result is discussed and their operation is interpreted as the application of an ideally “perfect” graphical curve selection or approximation method.2. The two-fold non-uniqueness of solutions obtained by the analogue computer is emphasized and it is shown that it is due to two reasons:—(a) the same pattern can be obtained by arrays with completely different individual aerial currents, (b) the same ideally required pattern curve can be approximated by different physically possible pattern curves.3. An RC variable phase-shifting circuit with dissipation compensation is described.4. A simple single-valve pulse generator of the “voltage-gate” type is described which serves, when driven by a saw-tooth wave voltage, as a pulse position modulator and phase modulator. It is thought that this pulse generator is of general interest, apart from its application described here.