Segmented Pad Electrode Design for Semiconductor Testing
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Solution Overview
Problem
The existing BGA type semiconductor devices face issues with pad electrode damage during testing and instability due to pressure from measuring needles, leading to moisture infiltration and corrosion, as well as warping or cracking caused by heat treatment, especially when organic insulation films shrink.
Innovation Solution
The semiconductor device design includes a second pad electrode for testing, which absorbs the pressure from the measuring needle, preventing damage to the primary pad electrode, and a protection film structure that covers the primary pad electrode but not the secondary one, stabilizing it during heat treatment and via hole formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a measuring needle contacts the pad electrode through an opening in the protection film for testing, then the electronic circuit can be tested, but the pad electrode is damaged and becomes unstable
Solution Approach 1:
The pad electrode is segmented into two distinct parts: a first pad electrode for external connections and a second pad electrode for testing. This segmentation allows the testing function to be separated from the signal transmission function, so that testing operations do not damage the primary pad electrode structure.
Solution Approach 2:
The second pad electrode serves as an intermediary element that absorbs the mechanical stress and damage from measuring needle contact during testing. This intermediary structure protects the first pad electrode from direct damage while still enabling test signal transmission.
2Reliability
If an opening is provided in the protection film for measuring needle contact, then testing can be performed, but the pad electrode warps or cracks during heat treatment
Solution Approach 1:
The protection film is segmented to cover the first pad electrode completely while leaving the second pad electrode exposed. This selective coverage maintains the structural integrity and stability of the first pad electrode during heat treatment, preventing warping and cracking.
Solution Approach 2:
Different regions of the device have different protection levels: the first pad electrode is fully covered by the protection film for stability during heat treatment, while the second pad electrode is intentionally left exposed to allow measuring needle contact for testing.
3Device complexity
If the first pad electrode is used for both testing and signal transmission, then device complexity is reduced, but the pad electrode is damaged by pressure from measuring needles
Solution Approach 1:
The pad electrode structure is segmented into two separate electrodes with distinct functions. The first pad electrode handles signal transmission and is protected from damage, while the second pad electrode handles testing operations and absorbs the mechanical stress from measuring needle contact.
Solution Approach 2:
The second pad electrode provides a universal testing interface that can be used for all test operations without affecting the primary signal transmission function of the first pad electrode. This multi-functional design maintains overall device simplicity while improving durability.
Data Source
AI summary
The invention prevents a pad electrode for external connection of a semiconductor device from being damaged. An electronic circuit, a first pad electrode connected to the electronic circuit, and a second pad electrode connected to the first pad electrode are formed on a semiconductor substrate. A first protection film is formed, covering the first pad electrode and having an opening on the second pad electrode only. A wiring layer is further formed, being connected to the back surface of the first pad electrode through a via hole penetrating the semiconductor substrate and extending from the via hole onto the back surface of the semiconductor substrate.