Self-Aligned Air Gaps in Microelectronics Packages
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Solution Overview
Problem
High-speed signaling in microelectronics is prone to degradation due to cross talk and signal interference between neighboring signal traces, which existing technologies fail to adequately address without compromising alignment and increasing costs.
Innovation Solution
The introduction of self-aligned air gaps between signal traces using a wet or dry etching process, where a positive type photo-imageable dielectric is used to encapsulate the traces, eliminating the need for costly alignment tools and reducing run rates by simplifying the process flow and enhancing control over air gap patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional alignment tools and methods are used to create air gaps between signal traces, then air gap formation is achieved, but alignment errors occur and manufacturing costs increase
Solution Approach 1:
The patent implements self-aligned air gap formation where the air gaps automatically align with signal traces through a single lithography step. The process uses a positive photo-imageable dielectric that is exposed and developed to create air gaps that are inherently aligned with the traces, eliminating the need for separate alignment tools and procedures. This self-service mechanism resolves the contradiction by achieving precise alignment without complex alignment equipment.
Solution Approach 2:
The patent applies preliminary action by forming the air gaps during the same lithography step that defines the signal trace positions. The positive photo-imageable dielectric is patterned in advance to create the air gap regions before metal deposition, ensuring that the air gaps are pre-positioned and aligned with the traces. This preliminary patterning eliminates subsequent alignment operations and their associated errors.
2Reliability
If larger air gaps are created between signal traces to reduce crosstalk, then signal integrity improves, but manufacturing complexity and costs increase
Solution Approach 1:
The patent changes the key parameter of the photo-imageable dielectric from negative to positive type, which fundamentally alters how the air gaps are formed. This parameter change enables the air gaps to be defined by the exposed regions rather than unexposed regions, allowing for larger, more controlled air gap dimensions that reduce crosstalk. The positive photo-imageable material responds to exposure by becoming soluble, enabling precise control over air gap size and shape through standard lithography parameters.
3Manufacturing precision
If multiple lithography steps are used to pattern air gaps with precise alignment, then air gap pattern control improves, but manufacturing costs and run rates decrease
Solution Approach 1:
The patent merges the air gap patterning function with the signal trace definition step into a single lithography operation. The positive photo-imageable dielectric serves dual purposes: defining the signal trace locations and creating the air gap regions simultaneously. This consolidation of functions into one lithography step eliminates multiple alignment and processing cycles, thereby improving manufacturing run rate while maintaining precise air gap patterning through the inherent alignment of the self-aligned process.
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 reduces crosstalk and improves signal integrity by creating larger air gaps without alignment errors, leading to better performance and lower manufacturing costs, while eliminating reliability risks associated with alignment errors.
Implementation Method 1
exposing the photo-imageable material to light; removing exposed portions of the photo-imageable material
Implementation Method 2
a wet or dry etching process
Data Source
AI summary
Disclosed herein are microelectronics package architectures having self-aligned air gaps and methods of manufacturing the same. The microelectronics packages may include first and second substrates, first and second traces, and a photosensitive material. The first trace may be attached to the first substrate and comprise a first sidewall. The second trace may be attached to the first substrate and comprise a second sidewall. The second traced may be spaced a distance from the first trace with the second sidewall facing the first sidewall. First and second portions of the photosensitive material may be attached to the first and second sidewalls, respectively. The second substrate may be attached to the first and second traces. The first and second substrates and the first and second traces may form the air gap in between the first and second traces.