Through-Silicon Via Insulation Segmentation
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Solution Overview
Problem
Conventional via-last methods for fabricating semiconductor devices with through-silicon vias (TSVs) often result in electrical short-circuiting between the TSVs and the silicon substrate, reducing the quality of the semiconductor device, and require reliance on external companies for forming insulating rings in via-first methods.
Innovation Solution
The method involves forming annular grooves and insulating layers around the TSVs, which are filled with insulating material to electrically separate the TSVs from the silicon substrate, preventing short-circuiting and allowing for in-house fabrication of semiconductor devices with TSVs using a via-last approach.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional via-last method is used to form through-silicon vias, then the fabrication process can be simplified, but electrical short-circuiting occurs between the TSVs and the silicon substrate
Solution Approach 1:
The patent divides the insulating structure into two segments: a bottom insulating film formed on the silicon substrate before TSV formation, and an annular insulating layer formed around the TSV after formation. This segmentation allows each insulating component to be optimized independently, ensuring complete electrical isolation while maintaining fabrication simplicity through the via-last approach
Solution Approach 2:
The bottom insulating film is formed in advance on the silicon substrate before the TSVs are created. This preliminary action ensures that the substrate surface is already insulated when TSVs are formed, preventing direct electrical contact between the TSV metal and substrate, thus eliminating short-circuiting risks from the outset
2Reliability
If a via-first method is used to form insulating rings, then insulation between TSVs and substrate is improved, but reliance on external companies is required
Solution Approach 1:
Instead of forming insulating rings around TSVs first (via-first method) and then forming the TSVs, this patent inverts the sequence by forming the TSVs first (via-last method) and then forming the annular insulating layer around them. This inversion enables complete in-house fabrication while achieving the same insulation effect, as all steps can be performed using standard semiconductor manufacturing equipment within one facility
3Productivity
If no annular insulating layer is formed around TSVs, then the fabrication process is simpler, but short-circuiting occurs between TSVs and substrate
Solution Approach 1:
The patent merges the formation of the bottom insulating film and the annular insulating layer into a unified insulating system. The bottom insulating film provides base insulation on the substrate, while the annular insulating layer provides additional radial insulation around the TSVs. Together, these two insulating components create a comprehensive electrical isolation barrier that prevents short-circuiting while maintaining fabrication efficiency
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 stabilizes insulation between TSVs and the silicon substrate, prevents short-circuiting, simplifies the fabrication process, and allows for independent formation of TSVs and insulating layers within one company, improving the quality and safety of semiconductor devices.
Implementation Method 1
forming an annular insulating layer in the annular groove and a bottom insulating film beneath the bottom surface of the semiconductor substrate by depositing an insulating material in the annular groove and on the bottom surface of the semiconductor substrate
Implementation Method 2
forming a through-silicon via electrically connected to the pad by depositing a conductive material in the electrode-forming hole
Data Source
AI summary
Methods of fabricating a semiconductor device including a through-silicon via that is electrically insulated from the semiconductor substrate. An exemplary method includes preparing a semiconductor wafer including a semiconductor substrate, a semiconductor element, an interlayer insulating, pads that are electrically connected to the semiconductor element, and a protective film; forming upper terminals electrically connected to the pads; forming annular grooves below the pads and extending to the interlayer insulating film; forming an annular insulating layer in the annular grooves and forming a bottom insulating film on the bottom surface of the semiconductor substrate; forming electrode-forming extending to the pads; filling the electrode-forming holes with a conductive material to form through-silicon vias electrically connected to the pads; and forming lower terminals on the bottom insulating film electrically connected to the through-silicon vias.