Capacitor Support Pads for Semiconductor Electrode Stability
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Solution Overview
Problem
Conventional methods for increasing cell capacitance in semiconductor devices, such as forming three-dimensional lower electrodes, are limited by electrode collapse and non-uniform material deposition due to stress from lattice-shaped supporting pads, leading to defects like bridges and leakages.
Innovation Solution
The use of capacitor support pads formed in stripes between lower electrodes, which reduce stress and allow for symmetric and uniform deposition of materials, and the implementation of a guard ring and external support pads to minimize the need for chemical mechanical polishing (CMP) processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If lattice-shaped supporting pads are used to support lower electrodes, then electrode stability is improved, but material deposition uniformity deteriorates due to narrow intervals between electrodes
Solution Approach 1:
The supporting pads are segmented into stripe-shaped structures arranged in parallel, rather than using a continuous lattice pattern. This segmentation creates larger intervals between adjacent electrodes while maintaining support functionality, allowing uniform material deposition across the electrode surfaces.
Solution Approach 2:
The supporting pads transition from a two-dimensional lattice pattern to extended stripe structures that span across multiple electrodes. This dimensional change allows the pads to support electrodes along their length while maintaining adequate spacing between adjacent electrode structures for uniform deposition.
2Reliability
If lower electrode height is increased to ensure sufficient capacitance, then cell capacitance is improved, but electrode structural stability deteriorates causing collapse or breakage
Solution Approach 1:
Stripe-shaped supporting pads are formed before the lower electrodes are fully structured, providing preliminary mechanical support during subsequent processing steps. This preliminary support prevents electrode collapse or breakage that would otherwise occur when increasing electrode height for sufficient capacitance.
Solution Approach 2:
The stripe-shaped supporting pads act as intermediary structures between the substrate and the tall lower electrodes. These pads provide mechanical support and stress distribution, enabling the lower electrodes to maintain increased height for sufficient capacitance without collapsing or breaking during processing.
3Shape
If conventional CMP process is used to remove oxide film level differences, then surface flatness is improved, but excessive material removal occurs leading to non-uniform oxide film thickness
Solution Approach 1:
Instead of using excessive CMP to remove all level differences, the patent applies partial CMP only where necessary to achieve adequate surface flatness. The stripe-shaped supporting pads are designed to provide sufficient support without requiring complete removal of oxide film level differences, thus avoiding excessive material removal and maintaining oxide film thickness uniformity.
Data Source
AI summary
A semiconductor device may include a semiconductor substrate and a plurality of first capacitor electrodes arranged in a plurality of parallel lines on the semiconductor substrate with each of the first capacitor electrodes extending away from the semiconductor substrate. A plurality of capacitor support pads may be provided with each capacitor support pad being connected to first capacitor electrodes of at least two adjacent parallel lines of the first capacitor electrodes and with adjacent capacitor support pads being spaced apart. A dielectric layer may be provided on each of the first capacitor electrodes, and a second capacitor electrode may be provided on the dielectric layer so that the dielectric layer is between the second capacitor electrode and each of the first capacitor electrodes. Related methods are also discussed.