Refractory metal capped low resistivity metal conductor lines and vias
First Claim
1. A method of creating a liner in high aspect ratio, submicron holes and lines comprising the step of sputtering a refractory metal or an alloy or compound thereof through a collimator into a high aspect ratio, submicron hole or line at a pressure where scattering deposition dominates to create a liner effective to inhibit diffusion.
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Abstract
Capping a low resistivity metal conductor line or via with a refractory metal allows for effectively using chemical-mechanical polishing techniques because the-hard, reduced wear, properties of the refractory metal do not scratch, corrode, or smear during chemical-mechanical polishing. Superior conductive lines and vias are created using a combination of both physical vapor deposition (e.g., evaporation or collimated sputtering) of a low resistivity metal or alloy followed by chemical vapor deposition (CVD) of a refractory metal and subsequent planarization. Altering a ratio of SiH4 to WF6 during application of the refractory metal cap by CVD allows for controlled incorporation of silicon into the tungsten capping layer. Collimated sputtering allows for creating a refractory metal liner in an opening in a dielectric which is suitable as a diffusion barrier to copper based metalizations as well as CVD tungsten. Ideally, for faster diffusing metals like copper, liners are created by a two step collimated sputtering process wherein a first layer is deposited under relatively low vacuum pressure where directional deposition dominates (e.g., below lmtorr) and a second layer is deposited under relatively high vacuum pressure where scattering deposition dominates (e.g., above 1 mTorr). For refractory metals like CVD tungsten, the liner can be created in one step using collimated sputtering at higher vacuum pressures.
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Citations
18 Claims
- 1. A method of creating a liner in high aspect ratio, submicron holes and lines comprising the step of sputtering a refractory metal or an alloy or compound thereof through a collimator into a high aspect ratio, submicron hole or line at a pressure where scattering deposition dominates to create a liner effective to inhibit diffusion.
- 10. A method of creating a liner in high aspect ratio, submicron holes and lines comprising the step of sputtering a metal or an alloy or compound thereof into a high aspect ratio, submicron hole or line pressure where directional deposition dominates, without collimation, to create a liner effective to inhibit diffusion.
Specification