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US 5,851,899 AGranted
Gapfill and planarization process for shallow trench isolation
AssigneeSiemens Aktiengesellschaft
InventorPeter Weigand
Life of this patent
Estimating the term…
Abstract
Described is a method for filling shallow trench isolation (STI) trenches in a semiconductor substrate of an integrated circuit with an insulating material and planarizing the resulting structure to the level of adjacent portions of the integrated circuit. The method comprises forming trenches in the non-active regions of a semiconductor substrate, depositing a layer of oxide in the trenches and over the surface of the semiconductor substrate, and removing the oxide from the active areas of the integrated circuit structure, leaving oxide-filled shallow trench isolation structures having a substantially planar topography with respect to the rest of the integrated circuit structure.
Claims23
A method for fabricating devices including the step of forming isolation between device structures fabricated on a substrate comprising:
- defining active and non-active regions on a surface of the substrate;
- forming isolation trenches of varying widths the active regions comprising active regions of varying width in the non-active regions;
- forming a layer of HDP-CVD insulating material of silicon oxide, wherein the HDP-CVD silicon oxide layer is non-planar and protrudes angularly above isolation trench edges forming sloping edges that slope away from the trench on the substrate by high density plasma-enhanced chemical vapor deposition (HDP-CVD), the HDP-CVD layer substantially filling the trenches and covering the active regions;
- removing at least a portion of the insulating material covering the active regions;
- and
- planarizing the surface of said substrate to expose the active regions, the removal of at least a portion of insulating material from the active regions providing a planar topography;
- wherein removing of at least a portion of the insulating material from the active regions includes:
- depositing a mask layer over the insulating material;
- patterning the mask layer to expose at least a portion of the insulating material over the active regions;
- and
- removing the exposed portion of the insulating material over the active regions, leaving unexposed portions of the insulating materials;
- and wherein the mask layer is deposited using an inverse active area mask that is biased so that the mask layer after patterning covers the non-active regions and at least a portion of the active regions.
9 more elements
A method for fabricating devices including the step of forming isolation between structures fabricated on a substrate comprising:
- defining active and non-active regions on a surface of the substrate, wherein the non-active regions comprise narrow and wide non-active regions and active regions comprise narrow and wide active regions;
- forming isolation trenches in the non-active regions;
- forming a layer of HDP-CVD insulating material of silicon oxide that is non-planar and protrudes angularly above isolation trench edges forming sloping edges that slope away from the trench on the substrate by high density plasma-enhanced chemical vapor deposition (HDP-CVD), the HPD-CVD layer substantially filling the trenches and covering the active regions;
- removing at least a portion of the insulating material covering the wide active regions;
- and
- planarizing the surface of said substrate to expose the active regions, the removal of at least a portion of insulating material from the wide active regions enabling a planar topography to be provided by the planarizing step;
- wherein removing at least a portion of the insulating material from the wide active regions includes:
- depositing a mask layer over the insulating material;
- patterning the mask layer to expose at least a portion of the insulating material over the wide active regions;
- and
- removing the exposed portion of the insulating material over the wide active regions, leaving unexposed portions of the insulating materials;
- and wherein the mask layer is deposited using an inverse active area mask that is biased so that the mask layer after patterning covers the non-active regions and at least a portion of the wide active regions.
9 more elements
A method for fabricating devices including the step of forming isolation between structures fabricated on a substrate comprising:
- defining active and non-active regions on a surface of the substrate, wherein the non-active regions comprise narrow and wide non-active regions and active regions comprise narrow and wide active regions;
- forming isolation trenches in the non-active regions;
- forming a layer of HDP-CVD insulating material of silicon oxide that is non-planar and protrudes angularly above isolation trench edges forming sloping edges that slope away from the trench on the substrate by high density plasma-enhanced chemical vapor deposition (HDP-CVD), the HPD-CVD layer substantially filling the trenches and covering the active regions;
- removing at least a portion of the insulating material covering the wide active regions;
- wherein the removing of at least a portion of the insulating material from the active regions includes:
- depositing a mask layer over the insulating material;
- patterning the mask layer to expose at least a portion of the insulating material over the active regions;
- and
- removing the exposed portion of the insulating material over the active regions, leaving unexposed portions of the insulating materials;
- and
- planarizing the surface of said substrate to expose the active regions, the removal of at least a portion of insulating material from the wide active regions enabling a planar topography to be provided by the planarizing step;
- wherein the mask layer is deposited using an inverse active area mask that is biased so that the mask layer after patterning covers the non-active regions and at least a portion of the active regions.
9 more elements
A method of planarizing shallow isolation trenches in a substrate comprising:
- depositing a silicon oxide layer formed in an inductively coupled high density plasma chamber by chemical vapor deposition so as to fill said trenches and cover the surface of the substrate, thereby forming a non-planar layer over the surface that angles away from the edges of the trenches;
- depositing a photoresist layer on the oxide layer and patterning the photoresist layer with an inverse active area mask while biasing the layer so that the photoresist overlies at least a portion of the angled oxide layer;
- removing the silicon oxide in the exposed regions;
- removing the photoresist;
- and
- planarizing the surface of the substrate.
3 more elements
Dependencies are inferred from the claim text.