Sematech, Inc.

Ronald A Carpio

Rahul Jairath

Jayashree Kalpathy-Cramer

Buffered slurries are used in a semiconductor process for chemical mechanical polishing of metal layers, such as aluminum or titanium. The slurries may comprise an oxidant capable of causing a passive oxide film to form on a metal based layer. The oxidant may comprise a diluent and may be optionally formulated with a separate oxidizing agent, such as ammonium peroxydisulfate. The slurries may include a buffer that maintains a slurry pH where the passive metal oxide film is stable. This pH may be between about 4 and about 9.

Slurry formulation for chemical mechanical polishing of metals

Chemical mechanical polishing slurry characteristics, such as oxidant concentration and abrasive particle dispersion, are determined using electrochemical measurement techniques, such as chronoamperometry, amperometry, chronopotentiometry, ionic conductivity, or linear sweep potentiometry. Slurry characteristics may be tested and monitored independent of a CMP polishing tool. Slurry characteristics may also be automatically controlled in an on-line chemical mechanical polishing process using electrochemical measurements.

CMP slurry measurement and control technique

There is described a slurry for use in chemical mechanical polishing of copper layers in integrated circuit fabrication. The slurry includes a chromate oxidant, such as sodium chromate tetrahydrate (Na.sub.2 CrO.sub.4.4H.sub.2 O). The chromate oxidant provides a slightly basic slurry solution that enhances removal characteristics for copper layers. In one embodiment, the slurry has a pH between about 6 and about 9.

Copper chemical mechanical polishing slurry utilizing a chromate oxidant

A feedback control system for providing automated control of multi-component chemical concentrations in a hydrogen peroxide/ammonia (SC-1) aqueous bath or in a hydrogen peroxide/hydrochloric (SC-2) aqueous bath used for semiconductor processing. A sample from the liquid bath is routed to two sensors. Three separate schemes for determining concentrations of the two chemicals in the bath are provided by the selection of one of three separate pairs of sensors. A processor is used to monitor and control the chemical makeup of the bath.

Concentration measurement and control of hydrogen peroxide and acid/base

A feedback control system for providing automated and in-situ control of multi-component chemical concentrations in a liquid bath used for semiconductor processing. A sample from the liquid bath is injected into a carrier stream and routed to a conductivity detector and to an amperometric detector. Hydrogen peroxide concentration levels, as well as acidic or basic component concentration levels, are monitored and the measured readings are sent to a processor. If the concentration levels are not within tolerance for a given process, the processor meters in an appropriate amount of a needed chemical or diluting agent in order to bring the bath to an appropriate chemical concentration level. Additional detectors are employed in order to provide other types of analyses of the chemicals or contaminants present in the liquid bath and the amperometric detection need not be necessarily limited to H.sub.2 O.sub.2.

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Austin, TX, United States of America

Ronald A Carpio