Tapered Through Hole Structure for Semiconductor Reliability
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Solution Overview
Problem
The existing arrangement of through electrodes in semiconductor apparatuses, as disclosed in Japanese Patent Laid-Open No. 2013-140916, suffers from deteriorating conductive layer coverage as the distance increases from the tapered upper portion to the cylindrical bottom portion of the through hole, leading to reliability issues such as insulation failure and disconnection.
Innovation Solution
A semiconductor apparatus with a through hole featuring a tapered shape that changes at a specific position, where the first opening portion has a smaller taper angle than the second opening portion, and the through hole is formed using a combination of etching processes with varying anisotropy to ensure consistent coverage of the insulating layer and conductive member up to the bottom portion, preventing the formation of vertical streaks and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a wineglass-shaped two-stage through hole with tapered upper portion and cylindrical lower portion is formed, then the coverage of conductive layer on the tapered upper portion is improved, but the coverage of conductive layer on the cylindrical bottom portion deteriorates
Solution Approach 1:
The through hole is divided into two distinct regions with different taper angles: a first opening portion with a first taper angle and a second opening portion with a second taper angle. This local differentiation allows the upper portion to have better conductive layer coverage while the lower portion maintains adequate coverage, resolving the contradiction between improving coverage on the tapered upper portion and maintaining reliability at the bottom portion.
Solution Approach 2:
The patent changes the geometric parameters of the through hole by introducing two different taper angles instead of a single uniform taper angle. The first taper angle for the first opening portion is optimized for conductive layer coverage, while the second taper angle for the second opening portion is optimized to prevent coverage deterioration at the bottom, thus resolving the technical contradiction through parameter optimization.
2Manufacturing precision
If the distance from the tapered upper portion to the cylindrical bottom portion is decreased, then the coverage of conductive layer on the bottom portion improves, but the structural complexity of the through hole increases
Solution Approach 1:
Instead of uniformly decreasing the distance throughout the through hole, the patent applies local quality by creating a transition region with a specific second taper angle. This allows the distance to be optimized locally at the bottom portion to improve conductive layer coverage while maintaining a reasonable overall structure, avoiding excessive structural complexity.
Solution Approach 2:
The through hole is segmented into two distinct portions with different geometric characteristics. The first opening portion has one taper angle configuration and the second opening portion has another, allowing independent optimization of each segment. This segmentation enables the bottom portion to have adequate coverage without requiring the entire structure to be overly complex.
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 improves the coverage and reliability of the through electrode by maintaining effective insulation and connectivity, suppressing insulation failures and disconnection, and simplifying the manufacturing process by allowing the use of a thin conductive member and reducing the need for a plating layer.
Implementation Method 1
forming a concave portion forming a side surface of the first opening portion in the first substrate by etching the first substrate through an opening of the mask pattern, and forming the second opening portion by performing etching with higher anisotropy than in the forming the concave portion
Data Source
AI summary
A semiconductor apparatus comprising a first substrate that has a first surface and a second surface and is provided with a through hole extending through from the first surface to the second surface and an insulating layer and a conductive member that are provided in the through hole is provided. The through hole includes a first opening formed in the first substrate and a second opening provided between the first opening and the second surface. The first opening and the second opening each have a tapered shape whose opening width decreases from the first surface to the second surface, and a first taper angle formed by a side surface of the first opening and a plane parallel to the second surface is smaller than a second taper angle formed by a side surface of the second opening and a plane parallel to the second surface.