Electrochemical Technology CorporationDryScrub


History of DryScrub, DRYSCRUB, ETC

DryScrub, Electrochemical Technology Corporation (ETC) was founded in October 1986. Electrochemical Technology Corporation was the company name used from 1986 till the end of 2002. DryScrub is the product name. The popular recognition of the DryScrub System prompted us to use DryScrub as the company name and preserved the long Electrochemical Technology Corporation name as ETC. From 2003 on, DryScrub ETC is adapted as the company name.

To achieve today's desired process results, gas flows must be set high enough to ensure that a balance is achieved between film thickness, uniformity, and film stress, as a direct result, in excess of 80% of the total reactant gases flow through the process area 'unused'. This 'unused' gas is then available to form by-products and/or films in the downstream lines and equipment. These by-products can result in clogging of the lines or failure of the vacuum pumps with the consequent increase in maintenance requirements and lost production.

Dr. Ray Chiu, from his experiences with Plasma Etching and PECVD Process development had the idea that, under the correct conditions, a plasma process chamber could react the process gasses almost through to depletion and if this chamber was placed just after the process chamber, it would prevent most of the by-products being formed in downstream lines and equipment, and the passage of some toxic gas into the environment. Early experiments proved successful and the end result was the DryScrub system.

The first test of the prototype DryScrub system for a feasibility study was carried out at Genus Inc., a successful CVD equipment manufacturer, who were having problems in developing a new tungsten silicide CVD process. The issue with W-silicide was that the silane in the exhaust caused serious fire and maintenance hazards. The DryScrub prototype was nicknamed 'The Silane Eater' after it was found to efficiently convert the flammable silane into an amorphous silicon film deposited on the electrode, while the hydrogen gas passed through the exhaust system.

The success of this study in 1987 proved the new application of the plasma surface reaction technology and led directly to a patent application, which was granted (US Patent 4735633, April 5, 1988).

A pre-production model of the DryScrub System 1D was sent to Intel Development Fab 1 (Aloha, Oregon) for evaluation in reducing production problems caused by failures in the exhaust system and vacuum pumps for their LPCVD nitride process, very critical for the production of the (then) new Intel 386 microprocessor. The DryScrub system 1D model proved that its technology was sound and that it was a worthwhile investment for improving production. Dr. Leo Yau, the Intel Fellow, recognized the value of the system and approved and promoted it for installation within Intel.

As a result of the evaluation, Intel ordered two systems that were installed on production equipment. Because of the improvements the system offered, Intel worked with DryScrub, ETC to develop the 2D model. The 1D model and the 2D model used the same type of spiral electrode but the 2D offered easier maintenance of the DryScrub vacuum chamber. The first production batch of five 2D Chambers were purchased and installed in Intel fabs in Oregon. A further modification was made to reposition the RF feedthrough on the door instead of through the rear of the chamber and full production was then started with systems being sold to fabs Worldwide.

In 1998, as a general push was made to develop equipment for 300mm wafers, a larger version of the 2D model, the 2DX2, was developed. It was basically a 2D Chamber and electrode 'stretched' to twice their normal length. This was needed to double the waste collection capacity to meet the need of higher gas and exhaust waste throughput. On testing the new system, it was proved that the actual operation of the unit was the same as that predicted in the model, proving the reliability and understanding of the technology.

In the fall of 1999, whilst working with Tokyo Electron Limited (TEL), there was a strong requirement for a smaller system to be made to allow for easier mounting within equipment. As a result of this, a size specification was developed which led to the design of the Model 2DH DryScrub System. The 2DH model has a chamber diameter of 295mm that allows more versatile installation where space may be limited. The chamber volume was reduced to a half that of the 2D System but because of the novel design of the electrode, the collection capacity of the electrode was only reduced by 25%, also the new design increased the performance capabilities over that of the 2D system. New patent applications have been filed for this innovative design.

The 2DH model was a very successful product and immediately gain the recognitions by the industry. Several DRAM companies such as Samsung, Elpida and Micron all took the many advantages of the 2DH model, such as reduced process system maintenance, reduced vacuum components failures, and reduced wafer particle counts by installing many DryScrub systems. Many new applications are now also used the 2DH model as a standard components in the exhaust line to reduce particle counts, protect vacuum components, and for PFC abatement.

In 2003, when Cornell University was building its new Duffield Hall facility for the Cornell NanoScale Science & Technology Facility (CNF), the no foot print, high efficiency, ultra-low maintenance requirement which also enhanced the process stability and reproducibility advantages were recognized. The DryScrub 2DH systems were used as the true Point of Use (POU) scrubber throughout the facility. The 2DH DryScrub System is the prefer choice for universities for their gas abatement systems.

DryScrub, ETC is dedicated to the development and application of their plasma technology to the semiconductor processing and allied industries. As a result of this, DryScrub, ETC LEADS the field in the plasma treatment of exhaust gasses.

DryScrub, ETC is a technology driven company and has continued to serve its Customers, assisting them with in developing both existing and new applications for the DryScrub System. The DryScrub has implications for Process, Maintenance, Safety and the Environment with the associated benefits of reduced wafer production costs.

As production requirements change, so the DryScrub technology will be adapted and improved, enabling DryScrub, ETC to continue meeting it's Customers demands and expectations.



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