Semiconductor Pillar Planarization After Oxide Corner Rounding
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Solution Overview
Problem
The semiconductor industry faces challenges in achieving precise control of element configuration due to undesired oxidation of silicon pillars, leading to rounding of edges and uneven surfaces, which results in reduced contact area and electrical disconnection or high electric resistance between silicon pillars and landing pads.
Innovation Solution
A method is employed to form a planar surface on silicon pillars by forming a conformal oxide layer, followed by a planarization process to remove convex surfaces, and subsequent deposition of dielectric layers to ensure a uniform and planar top surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conformal oxide layer is formed over silicon pillars, then the oxide layer provides protective coverage, but the top corners of the pillars become convex due to oxidation
Solution Approach 1:
The patent applies planarization processing before forming subsequent dielectric layers to remove the convex surfaces created by oxidation. This preliminary action prevents the convex shape from affecting later fabrication steps and ensures proper planarity for subsequent layer deposition.
2Manufacturing precision
If oxidation occurs during conformal oxide layer formation, then the oxide layer is formed uniformly, but the top surface of pillars becomes non-planar
Solution Approach 1:
The planarization step is performed as a preliminary action before forming subsequent dielectric layers, removing the non-planar surfaces created during oxidation while preserving the uniformly formed oxide layer for continued use in later processing steps.
3Ease of manufacture
If convex surfaces are left on silicon pillars, then the fabrication process is simpler, but contact area with landing pads is reduced
Solution Approach 1:
The planarization processing is applied selectively to remove only the convex portions of the pillar surfaces while preserving the underlying oxide layer and maintaining overall structural integrity. This partial action achieves the necessary planarity for proper contact without requiring complete removal of oxidized material.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach prevents electrical disconnection and high electric resistance issues, enhancing device performance and product yield by maintaining a stable contact area between silicon pillars and landing pads.
Implementation Method 1
the formation of the first oxide layer includes oxidizing top corners of the plurality of pillars, thereby causing the top surface of each of the plurality of pillars to become a convex surface
Implementation Method 2
A planarization is performed on the plurality of pillars to partially or entirely remove the convex surface
Data Source
AI summary
The present application provides a semiconductor structure and a manufacturing method of the semiconductor structure. A substrate is provided, wherein the substrate includes a plurality of pillars, and a top surface of each of the plurality of pillars is a substantially planar surface. A first oxide layer is formed over the substrate conformal to the pillars, wherein the formation of the first oxide layer includes oxidizing top corners of the pillars, thereby causing the top surface of each of the plurality of pillars to become a convex surface. A first dielectric layer is formed among the pillars, wherein the first oxide layer above the plurality of pillars is partially exposed through the first dielectric layer. A planarization is performed on the pillars to partially or entirely remove the convex surface.