Multi-Barrier Conductive Pad Structure to Prevent Metal Extrusion
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Solution Overview
Problem
Existing semiconductor devices face issues with metal extrusion from conductive pads, leading to short circuits and reduced production yield and reliability, particularly with copper and aluminum-containing layers.
Innovation Solution
The implementation of a multi-barrier film structure, comprising a first barrier film and a second barrier film with a lower power deposition process, which has an amorphous structure and higher nitrogen atomic percentage, is used to prevent metal extrusion from the top metal layer and aluminum-containing layer, balancing tensile stress to enhance the quality of conductive pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single barrier film is used in the conductive pad structure, then the manufacturing process is simple, but metal extrusion occurs leading to short circuits and reduced reliability
Solution Approach 1:
The barrier film is segmented into multiple layers (first barrier film and second barrier film) with different materials and functions. The first barrier film (e.g., tungsten) provides initial metal extrusion resistance, while the second barrier film (e.g., tantalum nitride) provides enhanced barrier properties and stress balancing, collectively preventing short circuits without excessive complexity
Solution Approach 2:
The conductive pad structure uses composite materials combining different barrier film materials (e.g., tungsten + tantalum nitride, or titanium nitride + tantalum nitride) to achieve superior metal extrusion resistance and stress management properties that single materials cannot provide alone
2Reliability
If aluminum-containing layer is used for conductivity, then electrical conductivity is improved, but metal extrusion and short circuits increase
Solution Approach 1:
The first barrier film acts as an intermediary layer between the aluminum-containing conductive layer and the underlying metal layer. This intermediate barrier film (e.g., tungsten or titanium nitride) prevents direct contact and extrusion of aluminum into adjacent structures, enabling the use of aluminum for conductivity while preventing short circuits
3Manufacturing precision
If high power deposition process is used for barrier film, then deposition speed is fast, but film structure becomes crystalline reducing barrier effectiveness
Solution Approach 1:
The deposition parameters are changed by using low power conditions for the second barrier film deposition, which transforms the film structure from crystalline to amorphous. This amorphous structure provides superior metal extrusion resistance compared to crystalline structures, achieving better barrier quality despite slower deposition speed
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 solution effectively prevents metal extrusion, such as copper and aluminum, thereby improving the yield and reliability of semiconductor devices by avoiding short circuits and ensuring high-quality conductive pad structures.
Implementation Method 1
The second barrier film is formed using a second deposition process with a second level of power that is lower than the first level of power
Data Source
AI summary
Semiconductor devices are provided. The semiconductor device includes a substrate, an interconnect structure, and a conductive pad structure. The interconnect structure is over the substrate and includes a top metal layer. The conductive pad structure is over the interconnect structure and includes a lower barrier film, an upper barrier film, and an aluminum-containing layer. The lower barrier film is on the top metal layer. The upper barrier film is on the lower barrier film and has an amorphous structure. The aluminum-containing layer is on the upper barrier film. The lower barrier film and the upper barrier film are made of a same material, and a nitrogen atomic percentage of the upper barrier film is higher than a nitrogen atomic percentage of the lower barrier film.