Capacitor Opening Profile in Semiconductor Structures
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Solution Overview
Problem
The existing manufacturing methods for semiconductor structures face challenges in creating stable capacitors within memory devices due to limitations in the formation of dielectric layer stacks and etching processes, which affect the structural integrity and efficiency of capacitor formation.
Innovation Solution
A method involving the formation of a dielectric layer stack with specific oxide and nitride layers, where dopants like boron and phosphorus are used in the first oxide layer, and a sacrificial layer is etched to create openings that allow for the widening of the capacitor bottom, enhancing structural stability by adjusting dopant concentration and etching processes to form a stable capacitor structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional etching processes are used to form openings in dielectric layer stacks, then the manufacturing process is simple, but the structural stability and efficiency of capacitor formation are insufficient
Solution Approach 1:
The patent segments the etching process into multiple distinct stages: a first etching process to form initial openings through the dielectric layer stack, and a second etching process to widen the bottom portions of these openings. This segmentation allows each etching step to be optimized independently, with the first process creating precise initial openings and the second process enhancing structural stability by widening the base, thereby resolving the contradiction between structural stability and process complexity.
Solution Approach 2:
The patent applies preliminary action by first forming the dielectric layer stack with specific oxide and nitride layers before performing any etching operations. The openings are initially formed with controlled dimensions, and then the bottom portions are widened in a subsequent step. This preliminary structuring ensures that the capacitor formation process proceeds with enhanced structural stability from the outset.
2Reliability
If the opening width is increased to improve capacitor stability, then the structural stability improves, but the manufacturing precision required increases
Solution Approach 1:
The patent divides the opening formation into two segmented processes: the first etching process creates openings with controlled initial dimensions through the entire dielectric layer stack, while the second etching process selectively widens only the bottom portions of these openings. This segmentation allows precise control over different dimensional aspects - the overall opening size and the base width - thereby improving capacitor stability without requiring excessive manufacturing precision in a single step.
Solution Approach 2:
The patent applies local quality by widening only the bottom portions of the openings while maintaining the upper opening dimensions. This localized modification enhances the structural stability of the capacitor by providing a wider base for support, while the upper portions retain their original precision-critical dimensions. This selective widening resolves the contradiction by improving stability where needed without compromising overall manufacturing precision.
3Productivity
If dopant concentration is adjusted to enhance oxide layer properties, then the capacitor formation efficiency improves, but the manufacturing process complexity increases
Solution Approach 1:
The patent applies local quality by doping only specific oxide layers (the first and second oxide layers) with specific dopants (boron and phosphorus) at controlled concentrations, while leaving other layers (nitride layers) undoped. This selective doping enhances the electrical and structural properties of the dielectric layer stack where needed for capacitor formation, improving efficiency without requiring complex doping of the entire structure.
Solution Approach 2:
The patent utilizes parameter changes by adjusting the concentration of dopants (boron and phosphorus) in the oxide layers to optimize the dielectric properties and facilitate capacitor formation. By controlling dopant concentration as a variable parameter, the patent enhances capacitor formation efficiency while managing process complexity through systematic parameter optimization rather than fundamental process changes.
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 results in a more stable and efficient capacitor structure with wider bottoms, facilitating better support and easier material filling, thereby improving the overall semiconductor structure's reliability and performance.
Implementation Method 1
a first etchant used in the first etching process etches the sacrificial layer faster than etches the first oxide layer
Implementation Method 2
a second etchant used in the second etching process etches the first oxide layer faster than etches the sacrificial layer
Implementation Method 3
the first oxide layer is doped with a dopant, and the dopant comprises boron, phosphorus, or combinations thereof
Data Source
AI summary
A manufacturing method of a semiconductor structure includes forming a dielectric layer stack including a first oxide layer and a second oxide layer over the first oxide layer. An opening is formed in the dielectric layer stack, and includes a first portion exposing sidewalls of the first oxide layer and a second portion exposing sidewalls of the second oxide layer. A sacrificial layer is formed over the dielectric layer stack and along the sidewalls of the first oxide layer and the second oxide layer in the opening. A first etching is performed to remove the sacrificial layer along the sidewalls of the first oxide layer. A second etching is performed to widen the first portion of the opening. The sacrificial layer along the sidewalls of the second oxide layer and over the dielectric layer stack is removed. A capacitor is formed in the opening after removing the sacrificial layer.