Motorola Corporation

David A Shumate

Thomas R Baker

Bernard W Boland

Dan L Burt

Robert W Gray

Kevin A Lorenzen

An improved process is described for depositing TiW/TiWN/TiW/Au metallization which provides superior adhesion properties, excellent barrier properties and which is suitable for use with metal line widths of the order of one micron or smaller. It is important in order to obtain these properties to ensure that the layer immediately underlying the gold layer by substantially pure TiW deposited in a nitrogen free sputtering atmosphere. To this end, the gas supply manifolds and deposition chamber are purged and the chamber evacuated following deposition of the TiW layer and prior to deposition of the TiWN layer underlying the gold layer. A final TiW layer is also conveniently placed on top of the gold layer to act as an etching mask.

Metallization process

A sputter chamber with a rotatably mounted cathode nested in spacers, formed of the material sold under the trademark Teflon, and a quartz plate defining wafer receiving openings therethrough and affixed to the flat upper surface of the cathode in overlying relationship with the cathode and any exposed spacers to prevent sputtering of the spacers. If the material sold under the Trademark Teflon is sputtered fluorine containing ions are produced in the chamber plasma, which chemically etch masking materials such as titanium tungsten.

Sputter chamber with extended protection plate and method of use

A substantially planar dielectric wafer is formed by utilizing a polysilicon filler to remove surface irregularities (15, 15'). The polysilicon filler is formed by filling surface irregularities (15, 15') with polysilicon (19) and polishing the polysilicon (19) to form a substantially planar surface. A polishing stop (18) terminates the polishing and prevents damage to the wafer's isolated tubs (13). The polishing stop (18) can also be used as a mask during field oxide growth. The polysilicon filler also protects underlying areas (12) from subsequent etch operations. During subsequent field oxide growth, polysilicon layer (19) is converted to silicon dioxide which enhances dielectric isolation of each tub (13).

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Phoenix, AZ, United States of America

David A Shumate