Rear-Surface Through Electrode Formation in Semiconductor Devices
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Solution Overview
Problem
The manufacturing process of through electrodes in semiconductor devices is costly and prone to damaging semiconductor elements due to prolonged exposure to plasma during deep etching, and requires multiple steps including grinding and insulating film removal, which increases processing time and risk of element breakage.
Innovation Solution
A manufacturing process involving the formation of a ring-shaped trench and insulating film on the rear surface of the semiconductor substrate, followed by through hole creation from the rear surface side, allowing for surface protection and reduced plasma exposure, and subsequent electrode formation without the need for inner wall insulating films, thereby simplifying the process and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If deep etching is performed from the main surface side to form through holes, then through electrodes can be formed, but the etching time increases and semiconductor elements are damaged by prolonged plasma exposure
Solution Approach 1:
The patent applies inversion by forming through holes from the rear surface side of the semiconductor substrate instead of the conventional main surface side. This reverses the etching direction, allowing the semiconductor elements on the main surface to be protected from plasma damage while still achieving through hole formation. The rear surface etching process exposes the main surface gradually, preventing direct plasma exposure of the elements throughout the entire etching duration.
Solution Approach 2:
The patent applies preliminary action by forming a protective film on the main surface before performing rear surface etching. This protective film is prepared in advance to prevent plasma from reaching and damaging the semiconductor elements during the etching process. The protective film formation occurs before the harmful etching action, ensuring element protection throughout the through hole formation process.
2Manufacturing precision
If insulating films are formed on the inner walls of through holes and subsequent grinding and film removal steps are performed, then through electrodes can be formed, but the number of processing steps increases and manufacturing cost increases
Solution Approach 1:
The patent applies extraction by removing the unnecessary step of forming insulating films on the inner walls of through holes. The invention extracts only the essential through hole formation and electrode formation steps, eliminating the complex sequence of insulating film deposition, pattern formation, and removal steps that were previously required. This simplification reduces the total number of processing steps while maintaining through electrode functionality.
Solution Approach 2:
The patent applies segmentation by dividing the through electrode formation process into distinct functional stages: rear surface etching to create through holes, protective film formation on the main surface, and electrode material deposition. This segmented approach allows each step to be optimized independently and eliminates redundant operations, reducing overall process complexity compared to the conventional integrated approach requiring multiple film formation and removal cycles.
3Manufacturing precision
If multiple steps including grinding and insulating film removal are performed, then through electrodes can be formed, but processing time increases and the risk of element breakage increases
Solution Approach 1:
The patent applies continuity of useful action by performing rear surface etching and main surface protective film formation in a continuous sequence without intermediate grinding or film removal steps. The process maintains continuous productive action from through hole creation to electrode formation, eliminating idle time and redundant operations. This continuous approach significantly reduces total processing time compared to the conventional interrupted process requiring multiple grinding and film removal cycles.
4Manufacturing precision
If conventional main surface etching is used to form through holes, then through electrodes can be formed, but manufacturing cost increases due to multiple required steps
Solution Approach 1:
The patent applies inversion by etching from the rear surface instead of the main surface, which fundamentally changes the manufacturing approach. This inverted etching direction eliminates the need for subsequent main surface processing steps such as protective film removal and re-etching, thereby reducing the total number of manufacturing steps and associated costs while maintaining through electrode quality.
Solution Approach 2:
The patent applies preliminary action by forming the protective film on the main surface before rear surface etching begins. This preliminary protective film formation prevents the need for subsequent protective film removal and re-application steps that would increase manufacturing cost. The protective film is prepared in advance to last through the entire etching and electrode formation process, reducing overall manufacturing complexity and cost.
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 reduces manufacturing costs and improves yield by minimizing semiconductor element damage and streamlining the process, allowing for efficient formation of through electrodes without breaking semiconductor elements and reducing the number of processing steps.
Implementation Method 1
a through hole is formed in a semiconductor substrate from a main surface side of the semiconductor substrate by the dry etching using plasma
Implementation Method 2
at least two steps of grinding the semiconductor substrate and removing the insulating film at the bottom of the through hole are required for grinding the rear surface of the semiconductor substrate by CMP (Chemical Mechanical Polishing)
Data Source
AI summary
After forming a ring-shaped trench penetrating through a semiconductor substrate from a rear surface side thereof and forming an insulating film inside the trench and on the rear surface of the semiconductor substrate, a through hole is formed in the insulating film and semiconductor substrate on an inner side of the ring-shaped trench from the rear surface side, thereby exposing a surface protection insulating film formed on a front surface of the semiconductor substrate at a bottom of the through hole. After removing the surface protection insulating film at the bottom of the through hole to form an opening to expose an element surface electrode, a contact electrode connected to the element surface electrode is formed on inner walls of the through hole and opening, and a pad electrode made of the same layer as the contact electrode is formed on the rear surface of the semiconductor substrate.