Method for fabricating shallow trench isolation structure
AssigneeUnited Microelectronics Corp.
InventorsGwo-Shii Yang, Tri-Rung Yew, Coming Chen, Water Lur
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Abstract
A method for fabricating, a shallow trench isolation structure. A pad oxide layer and a silicon nitride layer are formed in sequence on a substrate. A trench is formed in the substrate and a liner oxide layer is formed on a sidewall of the trench. A doped silicon dioxide layer is formed on the silicon nitride layer and fills the trench. An annealing process is performed to density the doped silicon dioxide layer. A portion of the doped silicon dioxide layer is removed to expose the silicon nitride layer by a planarization process.
Claims22
A method for fabricating a shallow trench isolation structure, comprising the steps of:
- forming a trench in a substrate;
- forming a liner oxide layer on a surface of the substrate exposed within the trench;
- forming a doped silicon dioxide layer with a dopant concentration, so as to have a thermal expansion coefficient and a Young's modulus comparable to the substrate, over the substrate and filling the trench to be adjacent to the liner oxide layer in such a way that a stress incurred in a subsequent annealing process is reduced;
- performing the annealing process to densify the doped silicon dioxide layer;
- and
- performing a planarizing process to remove a portion of the doped silicon dioxide layer.
A method for fabricating a shallow trench isolation substrate, comprising the steps of:
- providing a substrate having a trench;
- forming a doped silicon dioxide layer over the substrate and filling the trench, wherein a material doped into the silicon dioxide layer is selected from a group consisting of germanium, nitrogen and refractory metals, and a dopant concentration level is controlled to have a thermal expansion coefficient and a Young's modulus comparable to the substrate;
- adjusting the doped material to have a mole percentage in the doped silicon dioxide layer such that a glass transition temperature of the doped silicon dioxide layer is reduced to allow a lower temperature for an annealing process;
- performing the for annealing process on the doped silicon dioxide layer;
- and
- performing a planarization process on the doped silicon dioxide layer.
A method for fabricating a shallow trench isolation structure, comprising the steps of:
- forming a trench in a substrate;
- filling a doped dielectric layer to the trench to form the shallow trench isolation structure, wherein the doped dielectric layer has a dopant concentration level that is controlled to have a thermal expansion coefficient and a Young's modulus comparable to the substrate;
- performing the annealing process to densify the doped dielectric layer;
- and
- performing a planarizing process to remove a portion of the doped dielectric layer.
The method of claim 32, wherein the doped dielectric layer comprises doped silicon oxide.
Dependencies are inferred from the claim text.