Aluminum-Copper Alloy Bottom Electrode for MIM Capacitor Bridging
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Solution Overview
Problem
In semiconductor device fabrication, stress migration and bridging issues between patterned conductive layers are exacerbated by insufficient control over electrode profiles and residual etching materials, leading to defects and performance degradation.
Innovation Solution
A method involving the formation of a bottom electrode layer with aluminum and copper, followed by an insulating layer and a top electrode layer, with an alloy process under controlled gas or vacuum conditions to improve stress migration efficiency and prevent bridging, while using barrier layers and thermal treatments to manage electrode profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the gap between two capacitors is decreased, then the device density is improved, but a bridging problem may occur due to etching residues remaining between capacitors
Solution Approach 1:
An additional etching process is performed before the main capacitor formation etching to remove potential etching residues in advance. This preliminary cleaning action prevents bridging problems that would otherwise occur when capacitors are placed close together, enabling higher device density without sacrificing reliability.
2Ease of manufacture
If the control of electrode profiles is improper, then the manufacturing process is simplified, but a short circuit problem may be generated
Solution Approach 1:
The etching process parameters are optimized and controlled to achieve proper electrode profiles. By carefully adjusting etching conditions, the patent ensures that electrode sides are properly formed without short circuits, maintaining reliability while managing process complexity through parameter optimization rather than additional process steps.
3Ease of manufacture
If the stress migration efficiency of metal electrode is insufficient, then the material selection is simplified, but the distribution of resistance shift becomes too broad to adversely affect charge storage characteristic
Solution Approach 1:
The patent uses composite metal electrode structures with specific material compositions designed to enhance stress migration efficiency. By selecting and combining specific materials with appropriate properties, the electrode achieves improved stress migration while maintaining controlled resistance shift distribution, thereby preserving charge storage characteristics without overly complicating the manufacturing process.
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 method enhances stress migration efficiency, suppresses hillocks, and prevents bridging issues between patterned conductive layers, ensuring improved charge storage characteristics and reduced resistance shift.
Implementation Method 1
an alloy process is performed to the bottom electrode material layer
Implementation Method 2
performing a thermal treatment process to form a surface treatment layer on the surface of the bottom electrode material layer
Implementation Method 3
The gas ambient includes hydrogen, nitrogen or combination thereof
Data Source
AI summary
A method of fabricating a semiconductor device includes forming a bottom electrode material layer containing aluminum and copper over the substrate. An insulating material layer and a top electrode material layer are sequentially formed on the surface of the bottom electrode material layer. A photoresist pattern is formed on the top electrode material layer, and then the top electrode material layer is patterned to form a top electrode by using the photoresist pattern as mask. The photoresist pattern is removed by plasma ash and then an alloy process is performed to the bottom electrode material layer. Thereafter, the insulating material layer, and the bottom electrode material layer are patterned to form a patterned insulating layer and a patterned bottom electrode layer.