United Microelectronics Corp.

Jiun Y Wu

Water Lur

Anna Su

Shih-Chanh Chang

Der Yuan Wu

A new method of metallization using a new design of metal contact shape, contact/via profile, and metal lines having considerably reduced current density and improved electromigration of metal lines is achieved. Metal contacts are formed in a rectangular shape instead of a square shape with the wider side perpendicular to the current direction. Contact openings are made having concavo-concave profiles which can provide a wider conducting cross-sectional area than can conventional openings with a vertical profile near the contact bottom. Gaps are formed within wide and high current metal lines so that current density can be effectively lowered by utilizing the whole metal line uniformly.

Metallization to improve electromigration resistance

A new method of forming a metal diffusion barrier layer is described. Semiconductor device structures are formed in and on a semiconductor substrate. At least one dielectric layer covers the semiconductor structures and at least one contact hole has been opened through the dielectric layer(s) to the semiconductor substrate. A metal diffusion barrier layer is now formed using the following steps: In the first step, a thin layer of titanium is deposited conformally over the surface of the dielectric layer(s) and within the contact opening(s) and annealed in a nitrogen atmosphere at a temperature of between about 580.degree. to 630.degree. C. for between about 20 to 120 seconds. The second step is to form stable and adhesive titanium compounds on the pre-metal dielectric layer as well as to form a low resistance silicide on the contact silicon by annealing at between about 800.degree. to 900.degree. C. for between about 5 to 60 seconds. The final step is to release the system stress by tempering the layer at a temperature of between about 600.degree. to 750.degree. C. This completes the barrier layer which has good adhesion to the dielectric layer(s) and, therefore, promotes improved pad bonding yield.

Method of making a reliable barrier layer

Metallization to improve electromigration resistance by etching

Method of forming wiring with gaps in bend to improve electromigration

Method of forming metallization to improve electromigration resistance

A method of forming field oxides with curvilinear boundaries between active regions on a substrate in an integrated circuit (IC) so that the stresses induced in the active regions due to the formation of field oxide can be reduced. Problems like junction leakage are reduced due to the rounded boundaries of the field oxides.

Field oxide with curvilinear boundaries and method of producing the same

Method of forming contact openings having concavo-concave shape

A new method of local oxidation by means of forming a plurality of silicon trenches is described. Portions of the insulating layer over the surface of a silicon substrate not covered by a mask pattern are etched through exposing the portion of the silicon substrate that will form the device isolation region. A first trench is etched into the exposed portion of the substrate. A layer of silicon nitride is deposited over the insulating layer and within the trench. A layer of an aluminum-silicon alloy is deposited overlying the silicon nitride layer. The aluminum-silicon layer is etched away whereby silicon nodules are formed on the surface of the silicon nitride layer. The nodules are oxidized to form silicon dioxide nodules. Using the silicon dioxide nodules as a mask, the silicon nitride layer is etched through to the insulating layer where it exists and to the silicon substrate surface where it is exposed and a set of narrow trenches is etched into the exposed portions of the substrate. The silicon substrate within the set of trenches is oxidized wherein the silicon is transformed to silicon dioxide and the silicon dioxide expands to fill the set of trenches. The silicon nitride layer and the silicon dioxide nodules within the opening are pushed up to align with the silicon nitride layer and the silicon dioxide nodules on either side of the opening. The remaining insulating layer and silicon nitride layer are removed wherein the silicon dioxide nodules are also removed completing the device isolation of the IC.

Growing community of inventors

Dou-Lio, Taiwan

Jiun Y Wu