UV Cutting Layer for Uniform Porous Low-k Interconnects
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Solution Overview
Problem
The non-uniform physical properties of porous low-k layers in interconnect structures due to varying numbers of UV-curing cycles, as lower layers receive more UV-irradiation than upper layers, leading to increased modulus, hardness, dielectric constant, and stress variations.
Innovation Solution
Incorporating a UV cutting layer, such as a UV reflection or UV reflection-absorption layer, between porous low-k layers to absorb or reflect UV light, preventing further curing of lower layers during UV-curing steps and ensuring uniform physical properties across layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If multiple UV-curing cycles are conducted to cure multiple porous low-k layers, then the physical properties (modulus, hardness, adhesivity) of the porous low-k layers are improved, but the physical properties become non-uniform across different layers due to varying numbers of UV-irradiation cycles
Solution Approach 1:
A UV cutting layer is introduced as an intermediary between adjacent porous low-k layers. This layer selectively blocks UV light from reaching lower layers during UV-curing processes, ensuring that each porous low-k layer receives a controlled and uniform number of UV-curing cycles. The UV cutting layer thus mediates the UV irradiation distribution to achieve uniform physical properties across all layers.
Solution Approach 2:
The interconnect structure is segmented into distinct layers with a UV cutting layer positioned between porous low-k layers. This segmentation allows independent control of UV irradiation for each porous low-k layer, preventing cumulative UV exposure effects and ensuring uniform curing characteristics across multiple layers.
2Speed
If porous low-k material is used to reduce parasitic capacitance and improve operation speed, then the RC delay effect and cross-talking effect are reduced, but the material requires multiple UV-curing cycles that cause non-uniform physical properties
Solution Approach 1:
The UV cutting layer serves as a mediator that enables the use of porous low-k material for high-speed operation while preventing the manufacturing defect of non-uniform physical properties. By blocking UV light selectively, it ensures uniform curing of porous low-k layers, maintaining their low dielectric constant properties necessary for high-speed operation.
Solution Approach 2:
The UV cutting layer is positioned locally between specific porous low-k layers to provide selective UV protection. This local application of the UV cutting function allows each porous low-k layer to maintain its specific physical properties uniformly, while still enabling the overall structure to achieve high operation speed through the use of low-k materials.
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
The UV cutting layer prevents over-curing of lower porous low-k layers, thereby improving the uniformity of their physical properties, such as modulus, hardness, and dielectric constant, across multiple UV-curing cycles.
Implementation Method 1
a first UV cutting layer at least between the first and the second porous low-k layers, wherein the first UV cutting layer is a UV reflection layer or a UV reflection-absorption layer
Implementation Method 2
a first UV cutting layer at least between the first and the second porous low-k layers, wherein the first UV cutting layer is a UV reflection layer or a UV reflection-absorption layer
Implementation Method 3
which can be treated with UV-curing to improve the physical properties thereof, including modulus, hardness and adhesivity, etc
Data Source
AI summary
An interconnect structure is described, disposed on a substrate with a conductive part thereon and including a first porous low-k layer on the substrate, a damascene structure in the first porous low-k layer electrically connecting with the conductive part, a second porous low-k layer over the first porous low-k layer and the damascene structure, and a UV cutting layer at least between the first and the second porous low-k layers, wherein the UV cutting layer is a UV reflection layer or a UV reflection-absorption layer.