Through Electrode Geometry for Insulation Film Formation
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Solution Overview
Problem
Existing semiconductor device technologies face challenges in achieving miniaturization and increased functionality due to limitations in forming reliable through electrodes and insulation films within narrow pitch layouts, with current techniques either making it difficult to form insulation films or resulting in poor connection reliability.
Innovation Solution
A semiconductor device design featuring a through electrode with a circular opening on one surface and a rectangular opening on the other, where the rectangular opening is smaller, allowing for a larger contact area with the electrode pad and enabling reliable insulation film formation on the inside wall surface, thereby enhancing connection reliability and allowing for miniaturization without increasing the joint area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a through hole is formed by laser beam or dry etching with tapered side wall to facilitate insulation film formation, then insulation film formation is improved, but the opening area is large which makes it unfit for narrow pitch miniaturization
Solution Approach 1:
The patent changes the geometric parameters of the through hole by forming a perpendicular side wall instead of a tapered wall, and by controlling the opening area to be smaller than the bottom area. This parameter change allows the opening area to be reduced for miniaturization while still enabling insulation film formation through the perpendicular geometry
Solution Approach 2:
The patent inverts the conventional approach by making the opening area smaller than the bottom area, rather than making the opening larger to facilitate film formation. This inversion resolves the contradiction by showing that perpendicular side walls enable film formation even with smaller openings
2Ease of manufacture
If the side wall of through hole is formed perpendicularly by Bosch process, then insulation film formation is improved, but overetching becomes necessary which causes notch formation making film formation difficult
Solution Approach 1:
The patent applies beforehand cushioning by designing the through hole with a bottom area larger than the opening area, which creates a geometric buffer that prevents notches from forming during overetching. The larger bottom area acts as a cushion that absorbs the overetching variation without creating harmful notches at the insulation film interface
Solution Approach 2:
The patent changes the geometric parameters by establishing that the bottom area is larger than the opening area, creating a positive geometric feature that compensates for overetching. This parameter change transforms the overetching from a harmful effect into a non-critical variation
3Reliability
If overetching is performed to prevent electrode pad deformation, then connection reliability is improved, but notch formation at insulation film interface occurs making film formation difficult
Solution Approach 1:
The patent uses beforehand cushioning by designing the through hole geometry with a larger bottom area that serves as a buffer zone. This cushioning effect prevents the overetching from creating notches at the insulation film interface, thereby maintaining both connection reliability and film formation capability
4Ease of manufacture
If intermediate part of through hole is widened by wet etching, then through hole formation is improved, but the enlarged intermediate part makes narrow pitch layout unattainable
Solution Approach 1:
The patent changes the geometric parameters by eliminating the widened intermediate part entirely and forming a through hole with perpendicular side walls and uniform cross-section. This parameter change reduces the area occupation while maintaining through hole formation capability, enabling narrow pitch layouts
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 design increases the reliability of the through electrode connection and allows for the reliable formation of insulation films within the through hole, addressing the limitations of existing techniques by eliminating shadowing effects and accommodating variations in etching rates and substrate thickness.
Implementation Method 1
a through hole is formed by a laser beam
Implementation Method 2
a through hole is formed by a laser beam, and an intermediate part of the through hole is widened by wet etching
Implementation Method 3
an intermediate part of the through hole is widened by wet etching
Data Source
AI summary
A semiconductor device has a through electrode formed in a through hole which penetrates a Si substrate from one surface to the other surface of the Si substrate, wherein a rectangular electrode pad is provided on the other surface with an insulation film laid between the electrode pad and the other surface, an opening of the through hole on the one surface side is circular, an opening of the through hole on the other surface side is rectangular, and the area of the opening on the other surface side is made smaller than the area of the opening on the one surface side.