Capacitor Electrode Stabilization via Sacrificial Etch Mask
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Solution Overview
Problem
The increasing density of integrated circuits poses a challenge in maintaining high storage capacitance due to the difficulty in etching deep capacitor electrode openings, which can lead to toppling of capacitor electrodes during fabrication and reduced capacitance.
Innovation Solution
The method involves forming a plurality of capacitors using a substrate with a capacitor array area and a surrounding circuitry area, employing insulative retaining materials and a hard-mask to stabilize capacitor electrodes during etching, and using selective isotropic etching to access underlying materials without creating a separating trench, allowing for increased capacitance and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If capacitor electrode openings are etched deeper to increase capacitance, then storage capacitance is improved, but the capacitor electrodes become toppling during fabrication
Solution Approach 1:
A sacrificial material layer is introduced as an intermediary between the capacitor electrode openings and the electrode material. This sacrificial layer acts as a temporary support structure during electrode formation, preventing toppling of deep electrodes, and is subsequently removed to expose the final electrode structure with increased capacitance.
Solution Approach 2:
The sacrificial material layer is deposited and patterned before the capacitor electrode material is formed. This preliminary action creates a protective framework that stabilizes the electrode structure during the critical formation process, allowing deep openings to be filled without electrode collapse.
2Quantity of substance
If the vertical dimension of capacitors is increased to maintain capacitance, then storage capacitance is improved, but the horizontal dimension must be reduced due to density requirements
Solution Approach 1:
The invention transitions from horizontal capacitor expansion to vertical capacitor growth by etching deeper openings and forming taller electrodes. The sacrificial material layer enables this vertical dimensionality change by providing temporary support during the vertical electrode formation process, allowing capacitance maintenance without increasing horizontal footprint.
3Stability of the object's composition
If sacrificial material layer is used to prevent electrode toppling, then electrode stability is improved, but the fabrication process complexity increases
Solution Approach 1:
The sacrificial material layer is designed to be temporarily introduced and then completely removed after serving its stabilizing function. This discarding approach simplifies the overall process by using a straightforward deposit-remove sequence rather than requiring complex in-situ support structures that would need to be integrated and retained in the final device.
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 enables the formation of stable capacitor electrodes with increased capacitance by preventing toppling and ensuring efficient etching, thereby addressing the challenge of maintaining high storage capacitance in densely packed integrated circuits.
Implementation Method 1
The capacitor electrode openings may be formed by etching
Data Source
AI summary
A method of forming a plurality of capacitors includes providing a plurality of capacitor electrodes, an elevationally inner insulative retaining material received laterally about the capacitor electrodes, an elevationally outer insulative retaining material received laterally about the capacitor electrodes, a first material received laterally about the capacitor electrodes elevationally inward of the inner insulative retaining material, and a second material received laterally about the capacitor electrodes elevationally between the inner and outer insulative retaining materials. Openings are anisotropically etched to extend through the outer insulative retaining material and the second material. After the anisotropic etching, remaining of the second material is isotropically etched through the openings from being received laterally about the capacitor electrodes between the inner and outer insulative retaining materials. The isotropic etching of the second material is conducted selectively relative to the capacitor electrodes and the inner and outer insulative retaining materials. The capacitor electrodes are ultimately incorporated into a plurality of capacitors.