Semiconductor Bottom Surface Wiring Thickness Control
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Solution Overview
Problem
Conventional semiconductor devices with through-hole electrodes face issues of separation due to thermal stress and metal diffusion, where the film thickness of the through-hole electrode and bottom surface wiring are interdependent, making it difficult to simultaneously prevent separation of both components.
Innovation Solution
A semiconductor device and manufacturing method where the bottom surface wiring has a greater film thickness than the through-hole electrode, particularly at the connection part with the external terminal, allowing independent control of film thickness to prevent separation caused by thermal stress and metal diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single conductive film is formed to create both the through-hole electrode and bottom surface wiring, then the manufacturing process is simplified, but the film thickness of both components is interdependent, making it difficult to prevent separation of either component
Solution Approach 1:
The single conductive film formation process is segmented into multiple independent formation stages. First, a conductive film is formed to create the through-hole electrode. Then, portions are selectively removed using etching or lift-off methods. Finally, the bottom surface wiring is formed by depositing additional conductive material. This segmentation maintains manufacturing feasibility while enabling independent film thickness control for each component, thereby preventing separation issues.
Solution Approach 2:
The through-hole electrode is formed in advance as a preliminary action before the bottom surface wiring is created. This sequence allows the through-hole electrode to be formed with its optimal thickness for thermal stress resistance, and then the bottom surface wiring can be subsequently formed with sufficient thickness for metal diffusion prevention, without the constraints of simultaneous formation.
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 ensures the through-hole electrode and bottom surface wiring are not separated due to thermal stress or metal diffusion, enhancing the reliability and durability of the semiconductor device by controlling their film thicknesses independently.
Implementation Method 1
a conductive film made of, for example, Cu is formed to cover the inner wall of the through hole and the bottom surface of the semiconductor substrate 100 using an electroplating method
Implementation Method 2
the conductive film constituting the through-hole electrode is deformed due to thermal stress generated by heat treatment during forming of the film and during forming of an external terminal after forming the film
Implementation Method 3
Cu of the bottom surface wiring 140 may melt into Sn of the external terminal 150 during a reflow process carried out when the semiconductor device is mounted on a mounting substrate
Data Source
AI summary
Disclosed herein is a semiconductor device including a semiconductor substrate, a wiring layer formed above the semiconductor substrate, a through-hole electrode extending from the bottom surface of the semiconductor substrate to the wiring layer, a bottom surface wiring provided at the bottom surface of the semiconductor substrate such that the bottom surface wiring is connected to the through-hole electrode, and an external terminal connected to the bottom surface wiring. The bottom surface wiring has a greater film thickness than a film thickness of the through-hole electrode at least a portion of the bottom surface wiring including a connection part between the bottom surface wiring and the external terminal.