Method of improving electromigration resistance of capped Cu
First Claim
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1. A method of manufacturing a semiconductor device, the method comprising:
- treating a surface of copper (Cu) or Cu alloy layer with a plasma containing nitrogen (N2) and ammonia (NH3) in a chamber to reduce copper oxide on the surface at;
an NH3 flow rate of about 210 to about 310 sccm; and
a N2 flow rate of about 8,000 to about 9,200 sccm; and
forming a capping layer on the treated surface of the Cu or Cu alloy layer.
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Abstract
The electromigration resistance of capped Cu or Cu alloy interconnects is significantly improved by treating the exposed planarized surface of the Cu or Cu alloy with a plasma containing NH3 and N2 under mild steady state conditions, thereby avoiding sensitizing the Cu or Cu alloy surface before capping layer deposition with an attendant improvement in electromigration resistance and wafer-to-wafer uniformity. Embodiments include treating the Cu or Cu alloy surface with a plasma at a relatively high N2 flow rate of about 8,000 to about 9,200 sccm and a relatively low NH3 flow rate of about 210 to about 310 sccm.
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Citations
11 Claims
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1. A method of manufacturing a semiconductor device, the method comprising:
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treating a surface of copper (Cu) or Cu alloy layer with a plasma containing nitrogen (N2) and ammonia (NH3) in a chamber to reduce copper oxide on the surface at;
an NH3 flow rate of about 210 to about 310 sccm; and
a N2 flow rate of about 8,000 to about 9,200 sccm; and
forming a capping layer on the treated surface of the Cu or Cu alloy layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
an RF power of about 50 to about 200 watts;
a temperature of about 300°
C. to about 400°
C.; and
a pressure of about 3 Torr. to about 5.0 Torr.
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4. The method according to claim 3, comprising treating the surface of the Cu or Cu alloy layer with the plasma for about 5 to about 25 seconds before introducing silane.
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5. The method according to claim 2, comprising introducing a wafer containing the Cu or Cu alloy layer into the chamber, wherein the Cu or Cu alloy layer fills an opening in a dielectric layer.
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6. The method according to claim 5, comprising:
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introducing N2 into the chamber;
introducing NH3 into the chamber;
elevating the pressure; and
initiating a plasma after about 10 to about 15 seconds.
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7. The method according to claim 2, wherein the Cu or Cu alloy layer constitutes a dual damascene structure comprising a Cu or Cu alloy line in contact with an underlying Cu or Cu alloy via formed in a dielectric layer.
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8. The method according to claim 7, wherein the dielectric layer comprises a dielectric material having a dielectric constant (k) less than about 3.9.
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9. A method of manufacturing a semiconductor device, the method comprising:
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introducing a wafer containing inlaid copper (Cu) or a Cu alloy into a chamber;
treating an exposed surface of the Cu or Cu alloy with a plasma containing ammonia (NH3) and nitrogen (N2) at;
an NH3 flow rate of about 210 to about 310 sccm;
a N2 flow rate of about 8,000 to about 9,200 sccm;
an RF power of about 50 to about 200 watts;
a temperature of about 300°
C. to about 400°
C.; and
a pressure of about 3 to about 5 Torr;
introducing silane (SiH4) into the chamber after treating the surface of the Cu or Cu alloy with the plasma; and
depositing a silicon nitride capping layer on the plasma treated Cu or Cu alloy surface. - View Dependent Claims (10, 11)
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Specification