Semiconductor Interconnect Structure With AlN Etch Stop Barrier
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Solution Overview
Problem
The reduction in size of active and passive devices in semiconductor substrates has complicated the formation and structure of interconnects, leading to challenges in preventing oxidation, corrosion, and the formation of hydride and hydroxyl impurities within these interconnects, which affects their efficiency and reliability.
Innovation Solution
The use of an etch stop layer, such as metal-doped aluminum nitride, is implemented between dielectric layers to prevent oxidation and corrosion of conductive lines and to inhibit the formation of impurities, while also ensuring adequate adhesion and etch selectivity, allowing for the formation of reliable interconnects through specific etching and deposition processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional photolithographic, etching, and deposition techniques are used to form interconnects, then interconnect formation is achieved, but oxidation, corrosion, and formation of hydride and hydroxyl impurities occur within the interconnects
Solution Approach 1:
A silicon nitride layer is introduced as an intermediary barrier between the copper interconnect and the surrounding environment. This intermediate layer prevents direct contact between copper and oxidizing/corrosive substances, thereby eliminating oxidation and corrosion while also preventing formation of hydride and hydroxyl impurities.
Solution Approach 2:
The silicon nitride layer creates an inert protective environment around the copper interconnect, isolating it from reactive substances. This inert barrier prevents harmful chemical reactions (oxidation, corrosion) and impurity formation by blocking exposure to moisture, oxygen, and other reactive species during and after fabrication processes.
2Productivity
If device size is reduced to improve integration density, then more devices fit on substrate, but interconnect formation becomes more complicated and difficult to control
Solution Approach 1:
The interconnect structure is segmented into distinct functional layers: copper interconnect layer and silicon nitride protective layer. This segmentation allows each layer to be optimized independently - copper for electrical conductivity and silicon nitride for protection - simplifying the overall formation process despite reduced dimensions.
Solution Approach 2:
The interconnect structure uses composite material design combining copper (conductive) with silicon nitride (protective). This composite approach provides both electrical functionality and environmental protection in a single integrated structure, reducing process complexity while maintaining high integration density.
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 effectively prevents oxidation and corrosion of interconnects and the formation of hydride and hydroxyl impurities, enhancing the reliability and efficiency of semiconductor interconnects by maintaining the etch stop layer's protective properties during the interconnect formation process.
Implementation Method 1
an etch stop layer, such as metal-doped aluminum nitride, is implemented between dielectric layers to prevent oxidation and corrosion of conductive lines
Implementation Method 2
inhibit the formation of impurities, while also ensuring adequate adhesion and etch selectivity
Data Source
AI summary
A device includes a substrate, a first dielectric layer over the substrate, a first conductive feature in the first dielectric layer, and an etch stop layer over the first dielectric layer. The etch stop layer includes metal-doped aluminum nitride. The device further includes a second dielectric layer over the etch stop layer, and a second conductive feature in the second dielectric layer. The second conductive feature extends into the etch stop layer and contacts the first conductive feature.