Method of depositing conductors in high aspect ratio apertures using a collimator
OwnerPei-Ing P. Lee, Thomas J. Licata +5inventors
InventorsPei-Ing P. Lee, Thomas J. Licata, Thomas L. McDevitt, Paul C. Parries, Scott L. Pennington, James G. Ryan, David C. Strippe
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Abstract
A process for sputter deposition wherein high aspect ratio apertures are coated with conductive films exhibiting low bulk resistivity, low impurity concentrations, and regular morphologies. A collimator is used having an aspect ratio that approximates the aspect ratio of the apertures.
Claims12
In a process for sputtering a barrier layer metallurgy comprising a refractory metal or refractory metal alloy from a sputter target into contact holes having side and bottom surfaces defined in an insulator arranged on a semiconductor substrate, at least some of the contact holes having an aspect ratio on the order of 2:1, the improvement comprising disposing a collimator between said sputter target and the substrate, said collimator being spaced from the substrate, said collimator having at least some openings with an aspect ratio of at least 1:1, and sputtering said refractory metal or refractory metal alloy at a pressure between approximately 0.7 mTorr and 3 mTorr, said refractory metal or refractory metal alloy being formed on said side and bottom surfaces of said contact holes and having a substantially uniform thickness at said side surfaces of said contact holes.
In a sputtering process for depositing a refractory metal or refractory metal alloy layer from a sputter target onto a substrate having at least some depressions therein with aspect ratios on the order of 2:1, each of said depressions having bottom and side surfaces, the improvement comprising disposing a collimator between the sputter target and the substrate, said collimator being spaced from the substrate, and sputtering said refractory metal or refractory metal alloy layer at a pressure between approximately 0.7 mTorr and 3 mTorr and at a substrate temperature of approximately 150.degree. C., said refractory metal or refractory metal alloy layer being formed on said side and bottom surfaces of said depressions and having a substantially uniform thickness at said side surfaces of said depressions.
A process for forming a Ti/TiN barrier layer within a 2:1 aspect ratio aperture formed within a passivation layer arranged on a substrate, comprising the steps of:
- sputtering a layer of titanium onto the substrate through a collimator having 1:1 aspect ratio openings therein, said collimator being spaced from the substrate, said layer of titanium being sputtered at a pressure between 0.7 mTorr and 3 mTorr;
- sputtering a layer of titanium nitride onto said layer of titanium through said collimator, said second sputtering step being carried out in a working gas consisting essentially of N2 and a pressure between 0.7 mTorr and 3 mTorr,
- said layers of titanium and titanium nitfide being formed on said sides and bottom of said aperture, and having a substantially uniform thickness on said sides of said aperture;
- and
- annealing said layers of titanium and titanium nitride in an N.sub.2 ambient to convert titanium on said sides of said aperture to titanium nitride.
A process for sputtering a layer of titanium nitride onto a substrate having at least one depression having side and bottom surfaces, said at least one depression having an aspect ratio on the order of 2:1, comprising the steps of
- forming said at least one depression on said substrate, and
- sputtering said layer of titanium nitfide onto the substrate through a collimator spaced from the substrate, said sputtering step being carded out at a pressure between approximately 0.7 mTorr and 3 mTorr, and in a working gas consisting essentially of N2,
- said layer of titanium nitride being deposited on said side and bottom surfaces of said at least one depression, said layer of titanium nitride being deposited at a substantially uniform thickness on said side surfaces of said at least one depression.
Dependencies are inferred from the claim text.