Conductive Contact Barrier Layers for Easier Contact Filling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor devices face challenges in forming conductive contacts due to vase-like or oval-shaped contact openings, which can lead to incomplete filling and degrade device performance or yield.
Innovation Solution
A unique fabrication process involving multiple etching-deposition cycles with different barrier layers, where each cycle etches the contact opening and deposits a barrier layer, followed by resputtering to remove the bottom segment, resulting in a staircase-like profile that is easier to fill, and allows for different material compositions to serve various roles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional vase-like or oval-shaped contact openings are formed, then the fabrication process is simple, but the filling is difficult and device performance degrades
Solution Approach 1:
The contact opening formation process is segmented into multiple etching-deposition cycles, where each cycle creates a portion of the final staircase profile. This segmentation transforms a single complex filling operation into multiple simpler steps, each dealing with a more manageable opening geometry.
Solution Approach 2:
The contact opening profile is transformed from a two-dimensional vase-like shape to a three-dimensional staircase structure with multiple terraces. This dimensional change in the profile geometry fundamentally improves fillability by eliminating the narrow neck region that causes filling difficulties.
2Reliability
If multiple barrier layers with different depths are formed, then leakage is prevented and silicide formation is promoted, but the fabrication process becomes more complex
Solution Approach 1:
Different barrier layers are deposited at different depths and locations within the contact opening, with each layer having specific material composition and thickness tailored to its local function. The first barrier layer prevents leakage at certain interfaces, while the second layer promotes silicide formation at others, optimizing performance locally throughout the structure.
Solution Approach 2:
The barrier structure uses composite materials with different properties distributed at different depths. By combining multiple barrier materials with distinct functional characteristics in a layered composite structure, the system achieves both leakage prevention and silicide promotion simultaneously, resolving the apparent contradiction between reliability enhancement and structural complexity.
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 improves the filling of contact openings, enhances device performance by preventing leakage and promoting silicide formation, and simplifies the fabrication process by using the same tool for deposition and resputtering, leading to more reliable and efficient semiconductor devices.
Implementation Method 1
a deposition process to deposit a barrier layer in the contact opening
Implementation Method 2
a resputtering process that removes a bottom segment of the deposited barrier layer
Data Source
AI summary
A semiconductor device includes a transistor having a source/drain and a gate. The semiconductor device also includes a conductive contact for the transistor. The conductive contact provides electrical connectivity to the source/drain or the gate of the transistor. The conductive contact includes a plurality of barrier layers. The barrier layers have different depths from one another.