Semiconductor Decoupling Capacitor Structural Collapse Prevention
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Solution Overview
Problem
The existing semiconductor fabrication methods risk inducing a collapsed structure with smaller arrays of decoupling capacitors, which can lead to performance issues in DRAM circuit design due to the standalone nature of these capacitors during the current fabrication process.
Innovation Solution
A method involving the formation of a dielectric stack with a first and second mask layer, where the second mask layer is patterned to create an opening between its central and peripheral portions, allowing for the etching of through holes and the formation of conductive layers, metal layers, and isolation layers to create a smaller capacitor design that avoids structural collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If smaller array of decoupling capacitors is used, then chip area is reduced and performance is improved, but structural collapse risk increases due to standalone fabrication
Solution Approach 1:
The patent merges multiple fabrication operations into a single integrated process. The method combines formation of through-holes, deposition of conductive layers, and creation of decoupling capacitors into one unified fabrication sequence, eliminating the need for separate standalone capacitor fabrication that causes structural collapse. This integration allows smaller capacitor arrays to be formed with improved structural support from the surrounding memory cell array.
Solution Approach 2:
The patent performs preliminary actions by forming the through-holes and conductive layers simultaneously with the memory cell array fabrication, before the capacitors would otherwise be formed as standalone structures. The conductive layers are deposited and patterned in advance, providing structural framework that prevents collapse during subsequent processing steps.
2Ease of manufacture
If traditional standalone capacitor fabrication is used, then manufacturing process is simpler, but capacitor size cannot be reduced further without causing collapse
Solution Approach 1:
The patent segments the capacitor structure into multiple components formed through distinct but integrated steps: through-holes through the dielectric stack, conductive layers for electrodes, and the dielectric material itself. This segmentation allows each component to be optimized independently while being formed in an integrated process, enabling smaller overall capacitor size without requiring complex standalone fabrication.
Solution Approach 2:
The patent transitions from planar capacitor formation to three-dimensional structures by forming through-holes vertically through the dielectric stack and filling them with conductive layers. This vertical dimensionality allows capacitors to be formed with smaller footprints while maintaining adequate structural support, overcoming the limitation of traditional planar fabrication.
3Area of stationary object
If integrated fabrication method is used, then capacitor size is reduced and performance improved, but manufacturing process complexity increases
Solution Approach 1:
The patent creates a universal fabrication process that serves multiple functions: forming memory cell arrays, creating through-holes, depositing conductive layers, and forming decoupling capacitors all in one integrated sequence. This multi-functionality reduces the need for separate dedicated capacitor fabrication equipment and processes, making the increased complexity manageable through process consolidation rather than multiplication.
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 creation of smaller capacitors that reduce the risk of structural collapse and enhance the performance of semiconductor structures by allowing for precise control over capacitor size and design.
Implementation Method 1
The dielectric stack is etched below the first through holes the second through hole
Implementation Method 2
A conductive layer is formed in the second through hole and on a top surface of the dielectric stack
Implementation Method 3
forming the metal layer on a bottom surface of the second through hole, such that the metal layer is in contact with the bottom metal
Implementation Method 4
removing an oxide layer of the dielectric layer of the dielectric stack before forming the conductive layer
Data Source
AI summary
A method of forming a semiconductor structure includes the following steps. A dielectric stack is formed on a bottom metal. A first mask layer is formed on the dielectric stack. The first mask layer has a plurality of first through holes, and a portion of the first through holes is in a central portion of the first mask layer. A second mask layer is formed on the first mask layer and in the first through holes. The second mask layer is patterned to form an opening between a central portion of the second mask layer covers the portion of the first through holes and is surrounded by the peripheral portion. The dielectric stack is etched below the first through holes the second through hole. A conductive layer is formed in the second through hole and on a top surface of the dielectric stack.