TSV Copper Plug Insulation Barrier for Metal Diffusion
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Solution Overview
Problem
In semiconductor devices, the diffusion of metal materials like copper into the substrate during manufacturing processes, such as etch processes, leads to deterioration and increased signal delays due to parasitic capacitance in three-dimensional integration structures.
Innovation Solution
A semiconductor device and manufacturing method involving a substrate with a plug and multiple insulation layers to prevent metal diffusion, where a sacrificial layer is used to form an opening and a plug is filled, with the insulation layers coating the substrate and plug surfaces to prevent metal diffusion during subsequent processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive metal layer such as copper is formed in the opening to create a TSV structure, then the electrical conductivity and integration density are improved, but the metal diffuses into the substrate during etch processes causing device deterioration
Solution Approach 1:
An insulation layer is introduced as an intermediary barrier between the copper plug and the silicon substrate. This insulation layer prevents direct contact and diffusion of copper atoms into the substrate during subsequent etch processes, while still allowing the TSV structure to provide low-resistance electrical connection.
Solution Approach 2:
The insulation layer is formed on the substrate surface before the copper plug is deposited. This preliminary protective action ensures that when the substrate is later exposed during etch processes to remove sacrificial materials, the copper plug is already protected from diffusing into the substrate.
2Manufacturing precision
If the substrate is repeatedly exposed during etch processes to remove sacrificial materials, then the manufacturing precision is improved, but the exposed metal layer diffuses into the substrate causing contamination
Solution Approach 1:
The insulation layer serves as a protective intermediary that allows the substrate to be exposed during etch processes for removing sacrificial materials while preventing copper diffusion. The etch process can access the sacrificial material through the opening without the copper plug being exposed to the substrate.
Solution Approach 2:
The insulation layer is preliminarily formed to cover the substrate surface before copper deposition. This preliminary protection remains in place during subsequent exposure steps, preventing contamination while allowing necessary manufacturing processes to proceed.
3Reliability
If copper is used as the conductive material due to its low resistance, then the electrical performance is improved, but the high diffusivity of copper causes deterioration of the semiconductor device
Solution Approach 1:
The insulation layer acts as a diffusion barrier that mediates between the copper plug and silicon substrate. It allows copper to be used for its excellent electrical conductivity while preventing the harmful diffusion of copper atoms into the silicon lattice during thermal processing and etch steps.
Solution Approach 2:
The insulation layer is selectively applied to the regions where copper-plugged vias are formed, providing localized protection exactly where the high-diffusivity copper material is present. This allows copper to be used in TSV structures while maintaining substrate integrity.
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 solution effectively prevents metal diffusion, enhancing the electrical reliability of semiconductor devices by ensuring that the metal does not contaminate the silicon substrate, thereby improving signal integrity and device performance.
Implementation Method 1
a second insulation layer is formed on outer surfaces of the plug in the substrate and the second connection portion
Data Source
AI summary
A method of manufacturing semiconductor device includes preparing a substrate having a first surface and a second surface opposite to the first surface. A first insulation layer is formed on the second surface. A sacrificial layer is formed on the first insulation layer. An opening is formed to penetrate through the substrate and extend from the first surface to a portion of the sacrificial layer. A second insulation layer is formed on an inner wall of the opening. A plug is formed to fill the opening. The sacrificial layer is removed to expose a lower portion of the plug through the second surface.