Through Substrate Inductor for Compact RF Integration
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Solution Overview
Problem
Conventional semiconductor device structures require large surface areas and have poor electrical quality, making aggressive integration challenging, and the separate formation of inductors increases production costs.
Innovation Solution
The use of through substrate coils and openings forming a kerf region, with a through substrate via and conductor coil in a semiconductor substrate, reduces surface area and improves electrical quality by using shared process steps and materials, thereby lowering production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional structures are used for inductor formation, then the inductor can be formed using standard processes, but the surface area required is large and electrical quality is poor
Solution Approach 1:
The inductor is formed as a through-substrate feature extending vertically through the semiconductor substrate, transitioning from a planar two-dimensional structure to a three-dimensional structure that utilizes the vertical dimension. This allows the inductor to achieve higher inductivity and better electrical quality within a reduced surface footprint by distributing the conductive path through multiple layers and depths of the substrate.
Solution Approach 2:
The formation of the through-substrate inductor is merged with the existing through-substrate via process sequence. The same etching, lining, and filling operations used to create through-substrate vias are applied to create the inductor structure, eliminating the need for separate inductor formation processes and reducing overall manufacturing complexity while achieving superior electrical performance in a compact area.
2Manufacturing precision
If separate formation processes are used for inductors, then inductor structures can be created, but production costs increase
Solution Approach 1:
The through-substrate inductor structure serves multiple functions: it provides the inductive element for RF circuits, acts as an integrated component within the substrate, and utilizes the same manufacturing infrastructure (etching, lining, filling processes) already established for through-substrate vias. This multi-functionality allows a single process sequence to achieve both via formation and inductor creation, eliminating redundant steps and reducing production costs.
Solution Approach 2:
The inductor formation process is merged into the through-substrate via process flow. The etching of through-substrate openings, deposition of liner materials, and filling with conductive material are combined operations that simultaneously create both through-substrate vias and through-substrate inductors, thereby reducing the total number of process steps and lowering manufacturing costs while maintaining high production precision.
3Manufacturing precision
If through substrate coils are formed, then inductivity increases and surface area decreases, but process complexity increases
Solution Approach 1:
The formation of through-substrate coils is merged with the standard through-substrate via process sequence. The same etching, lining, and filling operations used for vias are applied to create the coil structure, eliminating the need for separate coil formation processes. This integration reduces overall process complexity while achieving high inductivity in a compact area.
Solution Approach 2:
The coil structure is segmented into discrete turns or loops formed within the through-substrate opening, allowing the inductor to achieve high inductivity through multiple windings confined within a small vertical and lateral footprint. This segmentation enables the coil to pack more turns within the substrate thickness, increasing inductivity without proportionally increasing surface area or process complexity.
Data Source
AI summary
Through substrate features in semiconductor substrates are described. In one embodiment, the semiconductor device includes a through substrate via disposed in a first region of a semiconductor substrate. A through substrate conductor coil is disposed in a second region of the semiconductor substrate.