Stripe Supports Stabilize DRAM Lower Electrodes
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Solution Overview
Problem
Current semiconductor device fabrication techniques face challenges in maintaining sufficient capacitance while miniaturizing, as high-k dielectric layers require specialized equipment and processes, and maximizing lower electrode area is hindered by structural instability and delamination issues, especially at design rules below 0.14 μm.
Innovation Solution
The semiconductor device employs stripe-shaped supports at different levels to stabilize and surround lower electrodes, with each support engaging multiple electrodes, minimizing stress and preventing collapse, and a method involving multiple mold layers and etching processes to form these supports and electrodes efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the height of lower electrodes is increased to maximize effective area, then capacitance is improved, but the lower electrodes become unstable and prone to collapse
Solution Approach 1:
The support structure is divided into multiple segments at different heights (first support at first height, second support at second height greater than first height). This segmented approach provides distributed support along the height of the lower electrode, preventing collapse while allowing the electrode to maintain its increased height for maximum capacitance.
Solution Approach 2:
The support structure extends in the vertical dimension (height direction) with supports positioned at different heights rather than only at the base level. This multi-level support arrangement in the vertical dimension provides stability without limiting the horizontal footprint or the overall height of the lower electrode.
2Reliability
If the height of lower electrodes is increased to maximize effective area, then capacitance is improved, but manufacturing complexity increases
Solution Approach 1:
The mold layer serves multiple functions: it defines the pattern for the lower electrodes, provides structural support during fabrication, and acts as a template for the support structures. This multi-functionality reduces the need for separate dedicated structures or processes, simplifying overall fabrication despite the increased electrode height.
Solution Approach 2:
The support structures are formed using the mold layer as a template before the lower electrodes are fully constructed. This preliminary formation of supports at different heights establishes the stability framework in advance, allowing subsequent electrode material deposition to proceed without requiring complex real-time stabilization measures.
Data Source
AI summary
A semiconductor device and a method of fabricating a semiconductor device provide high quality cylindrical capacitors. The semiconductor device includes a substrate defining a cell region and a peripheral circuit region, a plurality of capacitors in the cell region, and supports for supporting lower electrodes of the capacitors. The lower electrodes are disposed in a plurality of rows each extending in a first direction. A dielectric layer is disposed on the lower electrodes, and an upper electrode is disposed on the dielectric layer. The supports are in the form of stripes extending longitudinally in the first direction and spaced from each other along a second direction. Each of the supports engages the lower electrodes of a respective plurality of adjacent rows of the lower electrodes. Each one of the supports is also disposed at a different level in the device from the support that is adjacent thereto in the second direction.