Conductive Through-Plating for Chip-Scale Packages
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Solution Overview
Problem
Existing through-plating technologies for chip-scale packages face issues such as high parasitic capacitances and mechanical stresses in etched trenches, and compatibility problems with highly doped silicon substrates, which affect conductivity and infrared transparency.
Innovation Solution
A method for producing conductive through-platings involving a grid structure with openings, etching, and metallization, where a metal component is positioned within trenches to create a seal, allowing for high conductivity and robustness while maintaining a planar substrate surface, enabling flexible use with various components and reducing the need for high conductivity substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If etched trenches packed with metals are used for through-plating, then conductivity is achieved, but high parasitic capacitances and considerable mechanical tensions are created
Solution Approach 1:
The through-plating is segmented into multiple metal layers separated by dielectric material. Instead of a single continuous metal trench, the conductive path is divided into discrete metal segments (first metal layer, second metal layer) that are electrically isolated from each other laterally by dielectric material, reducing parasitic capacitance while maintaining vertical conductivity
Solution Approach 2:
Dielectric material is introduced as an intermediary substance between the metal layers and surrounding substrate. This dielectric layer acts as a mediator that provides electrical insulation, reducing parasitic capacitance between adjacent metal structures, while also providing mechanical support and stress distribution
2Reliability
If free-standing silicon pillars with large cross-sectional area are used, then sufficient conductivity is achieved, but the substrate must be highly doped which is incompatible with component function and infrared transparency
Solution Approach 1:
The through-plating structure uses composite materials combining metal (for conductivity) and dielectric material (for insulation and mechanical support). This composite approach allows achieving sufficient conductivity through the metal pathways without requiring the entire substrate to be highly doped, thus preserving infrared transparency and component compatibility
Solution Approach 2:
High conductivity is achieved locally through metal pathways rather than requiring the entire substrate to have high conductivity. The metal layers provide concentrated conductive paths where needed, while the surrounding substrate can maintain its original properties including infrared transparency and low doping levels
3Area of stationary object
If through-plating with small cross-sectional area is used, then high conductivity at reduced area is achieved, but manufacturing complexity increases
Solution Approach 1:
The conductive pathway transitions from a lateral horizontal trench structure to a vertical stacked structure. By moving to the vertical dimension with multiple metal layers separated by dielectric material, the effective conductive cross-section is reduced while maintaining conductivity through the vertical path, and the manufacturing process is simplified by using standard sequential deposition and etching techniques
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 enables high conductivity at a small cross-sectional area, cost-effectiveness, and compatibility with different sensors and semiconductor components, while minimizing mechanical stresses and parasitic capacitances, allowing for efficient stacking and integration in chip-scale packages.
Implementation Method 1
in a second step which follows the first step, an etching step is carried out, during which at least one trench is produced both in the substrate and also at least partially underneath the group of openings
Implementation Method 2
in a fifth step which follows the second step, a metallization step is carried out, during which the metal component is at least partially positioned in the trench
Data Source
AI summary
A conductive through-plating for a substrate includes a metal component, a first conductive structure situated on or in the environment of a surface of the substrate, and a second conductive structure situated on or in the environment of a further surface of the substrate. A method for producing the through-plating includes, in a first step, at least partially applying above the surface a grid structure that includes a group of openings; in a second step following the first step, carrying out an etching producing a trench in the substrate and at least partially also underneath the group of openings; and, in a fifth step following the second step, carrying out a metallization situating a metal component at least partially in the trench such that the metal component is part of a seal sealing the trench in the area of the surface.