Ion Systems, Inc.

Michael G Yost

Arnold J Steinman

Scott J Gehlke

Donald A Gehlke

A test chamber is disclosed that permits standardized measurement of particles in the chamber environment. A device or structure that is suspected of the emitting particles and which is desired to be tested is located within the chamber. The chamber environment is then controlled by the introduction of filtered air thereby permitting both static measurements of particle emissions from the device or structure and flow through measurements of particle emissions from the device or structure.

Test chamber for particle emitters

Ion content of the atmosphere at a particular location is controlled by generating ions during repetitive period that are initiated by timing signals which reoccur at a predetermined rate. An ion sensor produces feedback signals indicative of the ion content of the air and a feedback circuit varies the duration of the recurring periods of ion generation, if necessary, to maintain the ion content within a predetermined range. Positive and negative ions may be generated during alternate ones of the repetitive periods in which case the feedback circuit inversely varies the periods of positive and negative ion generation to maintain the relative proportions of the two types of ion within a predetermined range. The method and apparatus may be used to suppress accumulation of electrostatic charge by objects, such as in a clean room where electronic components are manufactured, or for other purposes requiring control of the ion content of air.

Method and apparatus for regulating air ionization

Ion content of the air in a clean room or the like is controlled by generating positive and negative ions during alternating time periods using positive and negative high voltage generators connected to ionizing electrodes. Ion generation periods are followed by off intervals during which the ions disperse away from the electrodes before ions of opposite polarity are generated. In one aspect of the invention, each period of actuation of a high voltage generator of one polarity is followed by a momentary actuation of the high voltage generator of opposite polarity. This produces ions that are attracted to the electrode of the one polarity and then neutralize residual charge on the capacitors of the generator of the one polarity thereby assuring an abrupt termination of ion generation which can otherwise extend into the subsequent off period. In another aspect of the invention, each ion generation period is interrupted for an interval which varies in accordance with a feedback signal from an ion sensor in order to maintain air ion content within a desired range. The feedback signal is integrated to suppress the effects of brief localized fluctuations of air ion content on the signal thereby avoiding unnecessary over production of ions.

Potentially damaging electrostatic charges on semiconductor wafers or other objects are suppressed during the manufacturing process by generating ions in a flow of nitrogen or other non-reactive gas and by delivering the ionized flow to the product region through an enclosed flow path. The ions are produced by directing X-rays or other ionizing radiation into a shielded chamber portion of the flow path where flow is relatively slow and a large volume of gas is exposed to the X-rays. The ionized flow is then transmitted to the product region through a relatively narrow tubulation in which flow velocity is higher. Inter-relating of the flow rate and the length and diameter of the delivery tube minimizes ion loss from contact with the tube wall and from charge exchange with each other. The process and apparatus do not generate ozone or metallic particles, which can damage the products, as may occur with prior systems which use high voltage electrodes to ionize the air. The method and apparatus may also be used for other purposes such as air purification.

Method and apparatus for ionizing gas with point of use ion flow delivery

Apparatus for ionizing air molecules to suppress electrostatic charges in a room or for other purposes includes internal feedback which maintains a desired rate of ion production in the presence of electrode deterioration or other effects which could otherwise alter ion output. Production of air ions of a given polarity results in a ground return flow of electrical charges of opposite polarity from the high voltage generator at a rate corresponding to the rate of air ion output. The ground return current is monitored to produce an electrical feedback signal. A control circuit causes the high voltage generator to apply higher voltage to the electrode when the feedback signal decreases and to apply lower voltage to the electrode when the feedback signal increases. Such self-regulation of each individual electrode in systems having an array of electrodes that are otherwise jointly controlled acts to maintain a desired ratio of positive and negative ions in a room as well as a desired total ion concentration.

Self-regulating air ionizing apparatus

Positive and negative ion contents of the air within a region are controlled to suppress build-up of electrostatic charges on objects or for other purposes with one or more air ionizing units each having a positive high voltage generator coupled to a first ionizing electrode and a negative high voltage generator coupled to a second spaced apart ionizing electrode. The positive and negative high voltage generators are operated alternately with off times being provided between each period of ion generation of either polarity and the preceding period of generation of ions of the opposite polarity. The off times enable ions of each polarity to disperse outwardly for a controlled distance before substantial intermixing and mutual neutralization takes place. In the preferred form of the invention, the durations of the positive and negative ion generation periods, the off times between such periods and the rates at which each type of ion generation occurs during such periods are each separately controlled to accommodate to different ion requirements of different rooms or to changed conditions in a particular room.

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Berkeley, CA, United States of America

Michael G Yost