TiSSiEN：TCAD selected by the world's leading companies
TCAD International, Inc.
What's TCAD
TCAD (Technology Computer Aided Design) is a technology that solves equations representing manufacturing process of LSIs or transistors, or equations representing physical / chemical phenomena relevant to electrical conduction. TCAD simulates and predicts characteristics of a transistor or semiconductor circuit thereby increases the efficiency in designing and development of LSI. In other words, TCAD means a CAD technology that covers physical / chemical phenomena on semiconductors.
TCAD seems to be a difficult technology which is used only for developing leading-edge LSIs. However, in these days, actually measured data have been satisfactorily accumulated. Based on the satisfactorily accumulated data, the accuracy of calculation can be increased. TCAD is an extremely useful technology not only for developing new semiconductor products but also for legacy processes.
STRJ (Semiconductor Technology Roadmap Committee of Japan), which is constituted of semiconductor manufacturers in Japan, stated that, based on a survey, "simulation techniques like TCAD will give a large effect on not only development of new-age technologies but also development of derivative products."
FIG. 1
For developing a device structure capable of absorbing manufacturing variability
Even when dimensional differences are inevitable in manufacturing process, TCAD is useful to create a transistor which suffers little influence on its ON / OFF characteristics.
Technical papers from semiconductor manufacturers and / or academic meetings report many actual cases in which problems were solved by using TCAD technology. TCAD has contributed to development of semiconductor products in various aspects as listed below:
■ developing a semiconductor which suffers little influence on its ON / OFF characteristics even when dimensions may vary in manufacturing process
■ determination whether or not circuit operates erroneously due to electrical charge generated along a track of α-ray entering into a transistor or radiation, and selection of measures to prevent the erroneous operation
■ designing micro lens and its structure that effectively collects electron generated by the light entering into light receiving element such as CCD (Charge Coupled Device) used on a digital camera etc
■ determination how the current-voltage characteristic on a transistor is influenced by a stress given after thermal process depending on the layout of the adjacent transistors.
FIG. 2
A bird's eye view of a structure of four light receiving elements such as CMOS (center);
a sectional view of them (left); and a sectional view of light intensity distribution entered into pixel (right)
TCAD is useful for designing upper portion of pixels and / or the shape of internal lens.
By employing TCAD technology, technical data for developing semiconductor products can be accumulated so as to be retrieved anytime anywhere and precise information can be sheared among related persons and / or sections.
Also, engineers are allowed to experience various phenomena in a shorter time. TCAD technology will support to relay know-how and techniques necessary for creating products to the following engineers.
FIG. 3
shows a state in which electrons generated by radiation which enters vertically into SOI (Silicon On Insulator) transistor (upper thin plate-like portion) are absorbed into electrodes at both sides (up to 1nsec. from immediately after entrance).
From now on, semiconductor devices evolve while being sophisticated and miniaturized. Therefore, TCAD technology indispensable for designing and developing semiconductor devices will be closely linked with the miniaturization technology, and will be systematized so as to contribute to coordinate manufacturing process and design and development stages of semiconductor devices.
In order to achieve this, collaboration is indispensable among excellent engineers who own general knowledge of physics and chemistry and a wide rage technology such as numerical calculation, computing techniques etc. In this meaning, TCAD technology is recognized as a comprehensive technology.
