Redistribution Line Cap and Sidewall Barrier for Semiconductor Reliability
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Solution Overview
Problem
In semiconductor devices with redistribution lines, copper precipitates dendritically between adjacent lines, leading to withstand voltage deterioration and short circuits due to high electric fields and the presence of moisture and halogen ions in the organic protective film, which reduces the reliability of the device.
Innovation Solution
A semiconductor device design featuring a redistribution line with a cap metallic film and a sidewall barrier film, both made of insulating materials, that cover the upper and side surfaces of the redistribution line, preventing copper ion migration and moisture intrusion, and improving the diffusion barrier function to enhance reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the redistribution line is covered only with an organic protective film, then the manufacturing process is simple, but copper ions migrate through the film due to high electric fields and moisture, causing short circuits and reliability deterioration
Solution Approach 1:
The protective film is segmented into multiple functional layers: a lower protective film (inorganic insulating film) that provides copper ion migration barrier and an upper protective film (organic insulating film) that provides additional protection and planarization. This segmentation allows each layer to specialize in specific protection functions, preventing copper ion migration while maintaining manufacturing feasibility
Solution Approach 2:
The patent uses a composite protective film structure combining inorganic and organic materials. The inorganic lower protective film (e.g., silicon oxide, silicon nitride) provides excellent copper ion barrier properties, while the organic upper protective film provides additional protection and process compatibility. This composite structure leverages the complementary strengths of different materials to solve the reliability problem
2Productivity
If the minimum interval between adjacent redistribution lines is reduced to increase line density, then productivity improves, but the high electric field between closely spaced lines accelerates copper ion migration and causes short circuits
Solution Approach 1:
The protective film structure is established beforehand to prevent copper ion migration before it can occur. The inorganic lower protective film is formed to cover the redistribution line surface, creating a barrier that prevents copper ions from migrating into the organic protective film and causing short circuits, even when lines are closely spaced
Solution Approach 2:
The inorganic lower protective film acts as an intermediary barrier between the copper-containing redistribution line and the organic protective film. It mediates the interaction by blocking copper ion migration paths, thereby preventing the harmful effect of high electric fields from causing short circuits between closely spaced lines
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
The solution effectively prevents copper ion migration and moisture intrusion, thereby improving the reliability of the semiconductor device by reducing the occurrence of short circuits and withstand voltage deterioration between adjacent redistribution lines.
Implementation Method 1
the cap metallic film and the sidewall barrier film have parts overlapping with each other... effectively prevents copper ion migration
Implementation Method 2
preventing copper ion migration and moisture intrusion
Data Source
AI summary
The present invention makes it possible to improve the reliability of a semiconductor device. The semiconductor device has, over a semiconductor substrate, a pad electrode formed at the uppermost layer of a plurality of wiring layers, a surface protective film having an opening over the pad electrode, a redistribution line being formed over the surface protective film and having an upper surface and a side surface, a sidewall barrier film comprising an insulating film covering the side surface and exposing the upper surface of the redistribution line, and a cap metallic film covering the upper surface of the redistribution line. Then the upper surface and side surface of the redistribution line are covered with the cap metallic film or the sidewall barrier film and the cap metallic film and the sidewall barrier film have an overlapping section.