Method for forming a dual layer, low resistance metallization during the formation of a semiconductor device
First Claim
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1. A method used during the formation of a semiconductor device, comprising:
- providing a dielectric layer comprising at least one trench therein;
forming a first liner to line the trench;
forming a refractory metal blanket layer on the first liner;
performing an etch back of the refractory metal blanket layer such that the etched refractory metal layer fills between 5% and 50% of the volume of the trench;
forming a second liner which contacts the etched refractory metal layer;
forming a copper metal blanket layer on the second liner; and
polishing the copper metal blanket layer to result in a polished copper layer which fills the trench and is planarized with an upper surface of the dielectric layer.
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Abstract
A method for providing a highly reliable, low resistance interconnect comprises forming a trench in a dielectric layer, forming a first liner in the trench then forming a resilient layer such as a tungsten layer within the trench. The resilient layer is etched back to remove the layer from a horizontal portion of the dielectric outside the trench and to recess the layer within the trench. Next, a second liner and a copper layer are formed in the trench over the resilient layer. The copper layer and exposed portions of the two liners are polished or etched back to result in the interconnect. Variations to this embodiment are also described.
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Citations
19 Claims
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1. A method used during the formation of a semiconductor device, comprising:
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providing a dielectric layer comprising at least one trench therein;
forming a first liner to line the trench;
forming a refractory metal blanket layer on the first liner;
performing an etch back of the refractory metal blanket layer such that the etched refractory metal layer fills between 5% and 50% of the volume of the trench;
forming a second liner which contacts the etched refractory metal layer;
forming a copper metal blanket layer on the second liner; and
polishing the copper metal blanket layer to result in a polished copper layer which fills the trench and is planarized with an upper surface of the dielectric layer. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method used to form a conductive interconnect during the formation of a semiconductor device, comprising:
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forming a silicon dioxide layer comprising a major surface and an elongated trench;
forming a first conformal liner on the major surface and within the trench;
forming a refractory metal layer within the trench, over the major surface of the silicon dioxide layer, and on the first conformal liner;
performing an etch back on the refractory metal layer to recess the refractory metal layer within the trench and removing the refractory metal layer from over the major surface of the silicon dioxide layer;
subsequent to performing the etch back of the refractory metal layer, forming a second conformal liner on the refractory metal layer;
forming a conformal copper layer on the second conformal liner and within the trench; and
removing the copper layer from over the major surface of the silicon dioxide layer and leaving the copper layer within the trench to form an upper surface of the copper layer which is generally continuous with the major surface of the silicon dioxide layer. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. A semiconductor device comprising:
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a dielectric layer having a major surface and a trench therein;
a refractory metal layer within the trench which fills between 5% and 50% of the volume of the trench; and
a copper layer within the trench over the refractory metal layer, the copper layer comprising an upper surface which is generally continuous with the major surface of the dielectric layer. - View Dependent Claims (17)
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18. A semiconductor interconnect comprising, in a vertical cross-section:
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a first liner material defining a first elongated interconnect receptacle;
a refractory metal filling a portion of the first elongated interconnect receptacle defined by the first liner;
a second liner material covering the refractory metal and contacting the first liner, wherein the second liner material forms a second elongated interconnect receptacle; and
copper filling the second elongated interconnect receptacle, wherein a cross sectional area of the refractory metal filling the first elongated interconnect receptacle is equal to or less than a cross sectional area of the copper filling the second elongated interconnect receptacle. - View Dependent Claims (19)
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Specification