Internal Substrate Contact for 3D Integration Cross-Talk
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Solution Overview
Problem
In three-dimensional integration semiconductor substrates, through-silicon vias induce charge carriers that can generate high voltage, leading to cross-talk and electrostatic damage, as the substrate ground potential is not effectively applied to absorb these carriers.
Innovation Solution
A semiconductor device with internal substrate contacts, featuring contact holes and trenches that allow for direct contact metalizations on the semiconductor material, surrounded by a dielectric layer, and through-substrate vias, which are designed to absorb induced charge carriers and prevent electrostatic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If through-silicon vias are used to connect conductors on different substrates, then three-dimensional integration is achieved, but charge carriers are inductively coupled to the substrate causing high voltage that leads to cross-talk and electrostatic damage
Solution Approach 1:
A dielectric layer is introduced as an intermediary between the through-silicon via and the semiconductor substrate. This dielectric layer electrically isolates the via from the substrate, preventing inductive coupling of charge carriers to the substrate while maintaining the three-dimensional integration functionality
Solution Approach 2:
The substrate contact structure is segmented into multiple components: the through-silicon via, the dielectric layer, and the contact opening through the dielectric. This segmentation allows the via to be electrically isolated from the substrate bulk while still providing controlled electrical connections where needed
2Reliability
If the substrate is provided with an electrical contact at the rear surface, then the substrate can be maintained at a defined electric potential, but the ground potential cannot be applied to the semiconductor material surrounding the through-silicon via to absorb charge carriers
Solution Approach 1:
The dielectric layer is selectively positioned around the through-silicon via in the semiconductor substrate, creating local electrical isolation precisely where charge carrier induction occurs. This local modification allows the rest of the substrate to maintain its ground potential for absorbing charge carriers while the via region is protected from inductive coupling
3Ease of operation
If contact holes are made deep to reach internal substrate areas, then internal substrate contact is achieved, but the contact holes require precise depth control to avoid damaging underlying structures
Solution Approach 1:
The dielectric layer is deposited over the semiconductor substrate before etching the contact holes. This preliminary action creates a protective layer that prevents etching damage to underlying substrate structures. The contact holes are then etched through the dielectric layer to the desired depth, with the dielectric layer acting as a stop layer to prevent over-etching
Solution Approach 2:
The dielectric layer serves as a cushioning layer that protects the semiconductor substrate from damage during contact hole formation. By placing this protective layer beforehand, the etching process can proceed without risking damage to the substrate or underlying structures, providing a safety margin in depth control
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 internal substrate contacts effectively absorb charge carriers, preventing cross-talk and electrostatic damage, especially in high signal frequency applications, while maintaining the semiconductor material's conductivity and structural integrity.
Implementation Method 1
Electric signals that are transmitted on a through-silicon via are inductively coupled through the dielectric layer to the semiconductor substrate. A small number of induced charge carriers suffice to generate a high voltage
Data Source
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AI summary
The semiconductor device comprises a substrate (1) of semiconductor material, a contact hole (2) reaching from a surface (10) into the substrate, and a contact metalization (12) arranged in the contact hole, so that the contact metalization forms an internal substrate contact (4) on the semiconductor material at least in a bottom area (40) of the contact hole.