Semiconductor Pad Protection via Etch-Stop Layer and Aluminum
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Solution Overview
Problem
In semiconductor manufacturing, the exposure of copper lines in the scribe lane region during the packaging process leads to corrosion and potential damage, compromising the yield and reliability of semiconductor devices due to reaction with oxygen in the air.
Innovation Solution
A method involving the use of an etch-stop layer with a different etching rate than the insulation layers, comprising nitride, to prevent exposure of copper lines, along with aluminum pads to prevent corrosion and protect the copper lines from air exposure, ensuring the copper lines remain covered during the etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If passivation layers are removed in the scribe region to expose metal pads, then the pads can be accessed for electrical testing, but the copper inter-connection lines become exposed and susceptible to corrosion
Solution Approach 1:
The patent applies different etching rates to different layers (first insulation layer with higher etching rate, second insulation layer with lower etching rate) to achieve selective exposure. This local differentiation in etching characteristics allows the pad regions to be exposed while the inter-connection line regions remain protected, resolving the contradiction between pad accessibility and line protection
Solution Approach 2:
The patent performs preliminary patterning of the photosensitive layer to define regions where pads will be exposed versus regions where inter-connection lines will be protected. This preliminary action establishes the selective exposure pattern before the actual etching process, ensuring that copper lines are not exposed to corrosion while pads remain accessible
2Productivity
If copper inter-connection lines are exposed to air for a long time, then electrical testing can be performed, but copper corrosion occurs due to reaction with oxygen
Solution Approach 1:
The patent introduces an intermediary protective structure where the second insulation layer acts as a mediator that selectively covers the copper inter-connection lines while allowing pad access. This intermediary layer prevents direct contact between oxygen and copper lines, eliminating the harmful oxidation reaction while maintaining testing capability
Solution Approach 2:
The patent converts the harmful effect of oxygen exposure into a beneficial selective protection scheme. By controlling etching rates and patterning, the process that initially exposes copper lines is transformed to automatically protect them, turning the potential harm of exposure into a benefit of selective visibility where only pads are exposed and lines remain protected
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 solution effectively prevents copper line corrosion, reduces particle contamination, and enhances the yield and reliability of semiconductor devices by maintaining the copper lines' integrity and preventing exposure during the manufacturing process.
Implementation Method 1
An etch-stop layer with a different etching rate than insulation layers is formed to prevent exposure of a copper line
Implementation Method 2
aluminum pads to prevent corrosion and protect the copper lines from air exposure
Data Source
AI summary
A method of manufacturing a semiconductor device includes: forming a first pad including a first metal and an inter-connection line including the first metal in a scribe lane region; forming a second pad including the first metal in a chip region; sequentially forming an etch-stop layer and a first insulation layer on the first pad, the inter-connection line, and the second pad; exposing the first and second pads by patterning the etch-stop layer and the first insulation layer; forming third and fourth pads including a second metal on the first and second pads; sequentially forming second and third insulation layers on the third pad, the fourth pad, and the patterned first insulation layer; and etching the first, second, and third insulation layers using the patterned photosensitive layer on the third insulation layer to expose the third and fourth pads.