Method of forming metal layers formed as a composite of sub-layers using Ti texture control layer

Claim 1

A method of fabricating an integrated circuit which includes a composite metal layer, characterized in that said metal layer is formed by the steps of: depositing a texture control Ti layer at a first temperature so that said Ti layer has essentially a (200) basal plane orientation and subsequently deposited Al-based layers have essentially a <111> orientation, depositing an Al-based first sublayer at a second temperature on said Ti layer, while increasing the temperature from a third temperature to a peak temperature greater than said second temperature, depositing an Al-based second sublayer on said first sublayer so that a Ti-aluminide layer forms at least at the interface between said Ti layer and said first sublayer, and so that, at the end of its deposition, the grain size of said second sublayer is greater than that of said first sublayer, and at said peak temperature depositing an Al-based third sublayer on said second sublayer so that the microstructure of said sublayers adjusts itself to produce at most three grains.

Claim 2

A method of fabricating an integrated circuit which includes a composite metal layer, characterized in that said metal layer is formed by the steps of: depositing a texture control Ti layer at a first temperature so that said Ti layer has essentially a (200) basal plane orientation and subsequently deposited Al-based layers have essentially a <111> orientation, depositing an Al-based first sublayer at a second temperature on said Ti layer, while increasing the temperature from a third temperature to a peak temperature greater than said second temperature, depositing an Al-based second sublayer on said first sublayer so that a Ti-aluminide layer forms at least at the interface between said Ti layer and said first sublayer, and so that, at the end of its deposition, the grain size of said second sublayer is greater than that of said first sublayer, and at said peak temperature depositing an Al-based third sublayer on said second sublayer so that the microstructure of said sublayers adjusts itself to produce at most three grains.

Claim 11

The method as in any one of claims 1 to 9 further characterized in that said sublayers are deposited by sputtering.

Claim 12

The method as in any one of claims 1 to 9 wherein material islands are formed at the interface between said first and second sublayers.

Claim 16

A method of fabricating an integrated circuit comprising the steps of providing a silicon body which includes active device regions, forming an Al-alloy first layer at a first level in said circuit and in contact with at least one of said device regions, forming an Al-alloy second layer at a second level in said circuit, forming insulative layers separating said first and second layers from one another and separating said first layer from said device regions, forming an interconnect comprising a plug portion connecting at least one of said first and second layers or connecting said first layer and a device region, or both, characterized in that said plug portion is formed by the steps of: sputtering a first Ti layer and a TiN layer thereon, sputtering a texture control Ti layer on said TiN layer so that said control layer has a close-packed structure and essentially a (002) basal plane orientation and so that subsequently deposited Al-alloy sublayers have essentially a <111> orientation, sputtering an Al-alloy first sublayer on said control layer at a first temperature in the range of about 50°-100° C. so that said first sublayer has an average grain size of ≲2500 Å, sputtering an Al-alloy second sublayer on said first sublayer while the temperature is being increased from said first temperature to about 400°-500° C. so that a Ti-aluminide layer forms at least at the interface between said second Ti layer and said first Al-alloy sublayer and so that, at the end of the deposition of said second sublayer, said Al-alloy layers have an average grain size of about 2500-8000 Å; and sputtering an Al-alloy third sublayer on said second sublayer at a temperature of about 460°-500° C. so that the microstructure of said sublayers adjust themselves to at most three grains of size in the range of about 2500-10,000 Å.

Claim 17

A method of fabricating an integrated circuit comprising the steps of providing a silicon body which includes active device regions, forming an Al-alloy first layer at a first level in said circuit and in contact with at least one of said device regions, forming an Al-alloy second layer at a second level in said circuit, forming insulative layers separating said first and second layers from one another and separating said first layer from said device regions, forming an interconnect comprising a plug portion connecting at least one of said first and second layers or connecting said first layer and a device region, or both, characterized in that said plug portion is formed by the steps of: sputtering a first Ti layer and a TiN layer thereon, sputtering a texture control Ti layer on said TiN layer so that said control layer has a close-packed structure and essentially a (002) basal plane orientation and so that subsequently deposited Al-alloy sublayers have essentially a <111> orientation, sputtering an Al-alloy first sublayer on said control layer at a first temperature in the range of about 50°-100° C. so that said first sublayer has an average grain size of ≲2500 Å, sputtering an Al-alloy second sublayer on said first sublayer while the temperature is being increased from said first temperature to about 400°-500° C. so that a Ti-aluminide layer forms at least at the interface between said second Ti layer and said first Al-alloy sublayer and so that, at the end of the deposition of said second sublayer, said Al-alloy layers have an average grain size of about 2500-8000 Å; and sputtering an Al-alloy third sublayer on said second sublayer at a temperature of about 460°-500° C. so that the microstructure of said sublayers adjust themselves to at most three grains of size in the range of about 2500-10,000 Å.

Claim 22

The method of claim wherein said microstructure adjusts itself to produce two grains.