Semiconductor Contact Opening Sidewall Profile for Ion Blocking
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Solution Overview
Problem
Semiconductor devices are vulnerable to damage from mobile ions such as Fe, Cu, Al, and In due to the diffusion of these ions through the sidewalls of contact openings, which are not effectively blocked by conventional protective layers.
Innovation Solution
The semiconductor device features a dielectric layer with a concave-and-convex profile on its sidewalls, created through a specific etching process, which increases the path length for mobile ions and reduces their diffusion, thereby enhancing the device's reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional protective layers (silicon nitride, silicon oxide) are formed on the substrate, then the semiconductor device is protected from mobile ions, but the protective layers are easily damaged during contact opening formation, creating passages that allow mobile ions to pass
Solution Approach 1:
The protective structure is divided into multiple segments: the original protective layer and additional protective layers formed after contact opening formation. This segmentation allows each layer to serve specific functions - the first layer provides initial protection while the second layer reinforces protection in damaged areas, resolving the contradiction between protection and damage resistance
Solution Approach 2:
The patent applies preliminary action by forming the first protective layer before contact opening formation, then performing the damaging etching process, and finally forming additional protective layers to restore and enhance protection. This sequence ensures protection is established before damage occurs and restored after damage, resolving the timing conflict between protection and manufacturing processes
2Ease of manufacture
If the sidewall of the contact opening is made smooth, then the manufacturing process is simple, but mobile ions can easily diffuse along the sidewall and damage the semiconductor device
Solution Approach 1:
The patent applies curvature by forming a concave-convex profile on the contact opening sidewall instead of a smooth surface. The convex portions protrude into the opening while concave portions recess, creating a tortuous path that increases the distance mobile ions must travel and reduces their diffusion efficiency, thereby blocking harmful factors while maintaining manufacturing feasibility through standard etching processes
Solution Approach 2:
The patent changes the geometric parameter of the sidewall from smooth to concave-convex profile. This parameter change transforms the sidewall surface topology, increasing the effective path length for mobile ion diffusion by a factor of 1.5 to 3 times compared to smooth sidewalls, thereby reducing ion diffusion without significantly complicating the manufacturing process
3Device complexity
If a straight sidewall profile is used for contact openings, then the device structure is simple, but mobile ions have a short diffusion path and can easily reach the active area
Solution Approach 1:
The patent introduces curvature into the contact opening sidewall by forming a concave-convex profile where convex portions extend into the opening and concave portions recess. This curved, non-linear profile increases the diffusion path length for mobile ions, forcing them to traverse a longer, more complex route before reaching the active area, thereby improving reliability while maintaining relatively simple device structure
Solution Approach 2:
The patent adds dimensional complexity to the sidewall profile by creating variations in the radial dimension (convex and concave portions) rather than maintaining a simple cylindrical shape. This dimensional modification increases the path length in the radial direction, effectively blocking mobile ion diffusion without requiring changes to the vertical or lateral dimensions of the contact opening
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
The concave-and-convex profile effectively blocks the diffusion of mobile ions, reducing damage to the semiconductor device and improving its reliability by increasing the path length for these ions, thus protecting the active areas.
Implementation Method 1
performing a plasma etching process
Implementation Method 2
a first physical vapor deposition process and a second physical vapor deposition process are alternately performed
Data Source
AI summary
Provided is a semiconductor device and a method of manufacturing the same. The semiconductor device includes a substrate and a dielectric layer. The dielectric layer is located on the substrate. The dielectric layer has a plurality of openings, and side walls of the openings have concave-and-convex profile.