Self-Aligned Nitride Contact for High-Voltage Bonding Pads
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing technologies for making a physical connection between a passivation nitride layer and a high voltage metal bonding pad in integrated circuit chips either require specialized Nickel-Palladium finishing or a dedicated processing mask, which are not always available and add extra cost to the fabrication process.
Innovation Solution
A back end of line (BEOL) process that uses a conformal nitride layer in contact with the bonding pad, self-aligned with a photosensitive insulator layer, eliminating the need for additional masks or specialized finishing processes by leveraging the masking used in defining the insulator layer to expose the bonding pad surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Nickel-Palladium finishing is used to make physical connection between passivation nitride layer and high voltage metal bonding pad, then reliability of connection is improved, but manufacturing complexity and cost increase due to specialized process requirements
Solution Approach 1:
The photosensitive insulator layer serves dual purposes: as part of the standard BEOL structure and as a self-aligned mask for etching the nitride layer. The masking function is inherent to the layer itself, eliminating the need for separate dedicated masks or specialized Nickel-Palladium finishing processes.
Solution Approach 2:
The photosensitive insulator layer performs multiple functions: it provides electrical insulation and simultaneously serves as a patterning mask for the nitride layer opening. This multi-functionality eliminates the need for separate dedicated masking steps required in conventional approaches.
2Ease of manufacture
If a dedicated processing mask is used to make connection between passivation nitride layer and metal bonding pad, then connection is achieved, but fabrication cost increases due to additional mask requirements
Solution Approach 1:
The photosensitive insulator layer is used for both its primary insulation function and as a patterning mask. This eliminates the need for additional dedicated mask materials and reduces overall mask consumption in the fabrication process.
Solution Approach 2:
The masking function is merged into the existing photosensitive insulator layer rather than requiring a separate dedicated mask layer. This combines multiple functions into a single structural element, reducing material consumption and process steps.
3Reliability
If Nickel-Palladium finishing is used for passivation layer finishing, then physical connection reliability is improved, but process availability decreases as not all technology platforms support it
Solution Approach 1:
The photosensitive insulator layer inherently provides the masking function needed for nitride layer patterning. This self-service approach eliminates dependence on specialized Nickel-Palladium finishing processes, making the solution compatible with all standard technology platforms that support basic photolithography.
Solution Approach 2:
The solution replaces expensive, specialized Nickel-Palladium finishing with standard, widely-available photolithography and etching processes. This uses common, accessible materials and methods that are universally supported across different manufacturing platforms.
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 enhances the reliability of the connection without increasing fabrication costs, as it allows for a self-aligned nitride layer contact with the bonding pad without requiring dedicated masks or specialized Nickel-Palladium finishing.
Implementation Method 1
a conformal nitride layer extending over the passivation structure and in contact with the upper surface of the last metal structure
Implementation Method 2
using the insulator material layer with the second opening as a mask to etch through the nitride layer and expose the upper surface of the last metal structure
Data Source
AI summary
A back end of line (BEOL) structure for an integrated circuit chip includes a last metal structure providing a bonding pad. A passivation structure over the bonding pad includes a first opening extending exposing an upper surface of the bonding pad. A conformal nitride layer extends over the passivation structure and is placed in contact with the upper surface of the bonding pad. An insulator material layer covers the conformal nitride layer and includes a second opening that extends through both the insulator material layer and the conformal nitride layer. A foot portion of the conformal nitride layer on the upper surface of the bonding pad is self-aligned with the second opening.