Semiconductor Device Back-Surface Cathode Connection
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Solution Overview
Problem
The manufacturing process of semiconductor devices with surface Zener diodes is complicated due to the need for insulating films to prevent contact failures, which also affects the compactness and luminance efficiency of high-brightness LED packages, as the use of Ag paste and insulating films can lead to increased main surface height and shadow issues.
Innovation Solution
A semiconductor device design where the protective diode's cathode electrode is electrically coupled to the back surface of the semiconductor chip without a PN junction, eliminating the need for Ag paste and insulating films, thus simplifying the manufacturing process and reducing the main surface height, while maintaining the required electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If surface Zener diodes are used to simplify packaging, then packaging ease is improved, but an insulating film must be formed to prevent contact failure making the manufacturing process more complicated
Solution Approach 1:
The patent transitions from surface-mounted electrodes to back-surface electrode connection, changing the spatial dimension of electrical coupling. The cathode electrode is electrically coupled to the back surface of the semiconductor chip without PN junction inside the chip, eliminating the need for insulating films on the surface and simplifying the manufacturing process while maintaining packaging ease
2Reliability
If Ag paste is used to electrically couple the electrode to the back surface, then electrical connection is achieved, but the main surface height increases reducing compactness
Solution Approach 1:
The patent extracts the Ag paste from the electrical coupling process by implementing direct back-surface electrode connection. The cathode electrode is electrically coupled to the back surface without requiring Ag paste, eliminating the height increase that would result from paste application and maintaining compact device dimensions while ensuring reliable electrical connection
3Reliability
If insulating films are formed on the back surface, then contact failure is prevented, but the manufacturing process becomes more complicated
Solution Approach 1:
The patent inverts the conventional approach by connecting the cathode electrode to the back surface without PN junction inside the chip, rather than forming insulating films on the back surface to prevent contact failure. This inversion eliminates the need for additional insulating film formation steps while maintaining contact reliability through the direct back-surface connection architecture
Data Source
AI summary
A semiconductor device simplifies the manufacturing process. The device includes a protective chip which has a surface Zener diode to protect a light emitting chip with an LED formed therein from surge voltage. The protective chip is mounted over a wiring electrically coupled through a metal wire to an anode electrode coupled to a p-type semiconductor region whose conductivity type is the same as that of the semiconductor substrate of the chip. The anode electrode of the protective chip is electrically coupled to the back surface of the chip without PN junction, so even if the back surface is in contact with the wiring, no problem occurs with the electrical characteristics of the Zener diode. This eliminates the need to form an insulating film on the back surface of the chip to prevent contact between the back surface and the wiring, thus simplifying the manufacturing process.