Via Filling Method for Microelectronic Devices
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Solution Overview
Problem
The challenge in microelectronics is the difficulty in filling vias with high aspect ratios, leading to voids and defects that affect the electrical reliability of microelectronic devices, particularly in three-dimensional architectures where via diameters are small compared to their height.
Innovation Solution
A method involving partial removal of the first filling material within the via to create a recessed portion with a lower aspect ratio, followed by a second filling with a different material or electrically conductive layers to improve the quality of the via, reducing voids and enhancing electrical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If via diameter is reduced to enable three-dimensional architectures, then device integration density is improved, but filling quality deteriorates due to high aspect ratios causing voids and defects
Solution Approach 1:
The via filling process is segmented into multiple steps: initial filling with first material, partial removal to create recessed portion, and second filling with different material. This segmentation allows each step to optimize for its specific purpose, avoiding the void formation problem of single-step filling in high aspect ratio vias
Solution Approach 2:
Different materials are used in different portions of the via - the first filling material fills the upper portion while the second filling material fills the recessed portion. This local differentiation of material properties addresses the specific filling challenges at different via locations, improving overall filling quality
2Length of moving object
If via aspect ratio is high, then device miniaturization is achieved, but electrical reliability deteriorates due to voids and filling defects
Solution Approach 1:
The first filling material is deposited preliminarily to fill the via, then partially removed to create the recessed portion before the second filling. This preliminary action prepares the via structure for the final filling step, ensuring that the second material can be deposited without forming voids in the critical electrical contact region
Solution Approach 2:
The via contains a composite structure with two different filling materials - the first filling material and the second filling material. This composite approach leverages the advantageous properties of each material in different via regions, improving electrical reliability by ensuring void-free filling in the recessed portion where electrical contacts are critical
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
The present invention relates to a method of making (11) a via (3) through a base layer (1) of a microelectronic device, comprising forming a hole (2) opening onto at least a first face (11) of the base layer (1) and filling the hole (2) with at least a first filling material, characterized in that it comprises at least a partial removal of at least a first filling material to a depth from the first face (11) of the base layer (1), the depth being strictly less than a thickness dimension of the hole (2), so as to produce a hollow portion (5), and in that it comprises a second filling, at least partial, of the hollow portion (5) with at least a second filling material.