Substrate Via with Conductive Structure for Mechanical Stability
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Solution Overview
Problem
Existing electronic devices with through-wafer vias lack mechanical stability and efficient area utilization due to the limitations of trench and via formation processes, which affect the precision and reliability of electrical connections in stacked configurations.
Innovation Solution
The formation of conductive structures within recessed regions of substrates, including through-substrate vias, with features like S-shaped patterns and space-compensating elements, allows for improved mechanical stability and efficient routing of electronic signals both vertically and laterally, enabling direct chip attach and solder attach processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If through-wafer vias are formed with simple wire structure, then manufacturing process is simple, but mechanical stability is poor
Solution Approach 1:
The via structure is segmented into multiple functional components: a conductive fill material forming the electrical pathway, a dielectric material filling the surrounding trench for mechanical support, and a structured configuration with the via extending through the substrate. This segmentation allows each component to perform its specific function while collectively providing both electrical connectivity and mechanical stability.
Solution Approach 2:
The via structure employs composite materials including conductive fill material (such as copper or aluminum), dielectric material (such as silicon dioxide or silicon nitride), and potentially metallic liners. This composite approach combines the electrical conductivity needed for signal transmission with the mechanical strength provided by the dielectric and substrate materials, resolving the contradiction between simple wire structure and mechanical stability.
2Reliability
If via width is increased to match bond pad area, then electrical connection area is sufficient, but area utilization efficiency decreases
Solution Approach 1:
The via structure implements local quality by concentrating the conductive fill material precisely where electrical connection is needed (in the via core), while the surrounding dielectric material provides mechanical support without compromising electrical performance. This allows the via to achieve sufficient electrical connection reliability with optimized dimensions, improving area utilization efficiency compared to uniformly enlarged via structures.
Solution Approach 2:
The via structure extends in the vertical dimension through the substrate thickness, allowing electrical connection to be achieved through the depth of the device rather than relying solely on lateral area expansion. This vertical dimensionality enables sufficient connection reliability with smaller planar footprints, improving area utilization efficiency.
3Ease of manufacture
If substrate is thinned by backgrinding, then via formation through substrate is enabled, but mechanical strength and handling stability decrease
Solution Approach 1:
The substrate is thinned by backgrinding before via formation, which is a preliminary action that enables subsequent via drilling and filling operations. By performing the thinning operation first, the device structure is prepared to accommodate through-substrate vias, and the substrate retains sufficient strength at this stage to withstand the mechanical stresses of subsequent processing steps.
Solution Approach 2:
The backgrinding process is controlled to remove material uniformly and stop at a predetermined thickness that provides adequate mechanical support. This beforehand cushioning approach ensures the substrate maintains sufficient strength to handle subsequent via formation operations while being thin enough to allow complete via penetration and reduce overall device height.
4Stability of the object's composition
If features are added within vias for improved stability, then mechanical stability increases, but manufacturing complexity increases
Solution Approach 1:
The via structure merges multiple functions into a single integrated feature: the conductive fill material simultaneously provides electrical connectivity and acts as a structural reinforcement element within the via. The dielectric material filling the trench combines mechanical support with electrical isolation. This merging of functions achieves improved mechanical stability without requiring separate additional structural features, thereby controlling manufacturing complexity.
Data Source
AI summary
An electronic device can include a substrate including a first region having a first thickness, and a second region having a second thickness different from the first thickness. The electronic device can include a via within the first region. The electronic device can include a conductive structure adjacent to the first region and connected to the via, wherein a combined thickness of the first thickness and a thickness of the conductive structure is thicker than the second thickness. In another embodiment, an interposer may have a similar structure, with laterally offset conductive structures that allow for lateral routing of electronic signals. A process of forming an electronic device can include forming a via and removing a portion of the substrate. The process can include forming a conductive structure connected to the via, wherein the conductive structure is adjacent to a region where the portion of the substrate has been removed.