Etch Stop Layer Protects Redistribution Layer During Carrier Substrate Removal
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Solution Overview
Problem
The challenge in semiconductor package fabrication is to prevent damage to the redistribution layer during the debonding process of the carrier substrate, particularly due to the thickness reduction trend in electronic devices requiring thinner packages while maintaining high performance and functionality.
Innovation Solution
A method is introduced that forms a metal etch stop layer between the carrier substrate and the redistribution layer, which allows for selective removal of the carrier substrate and release layer without damaging the redistribution layer, ensuring the integrity of the semiconductor package.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the carrier substrate is removed during the debonding process, then the semiconductor package can be completed, but the redistribution layer may be damaged
Solution Approach 1:
An etch stop layer is introduced as an intermediary between the carrier substrate and the redistribution layer. This layer facilitates the debonding process by providing a controlled interface for removal while protecting the redistribution layer from damage. The etch stop layer acts as a mediator that enables safe separation of the carrier substrate without directly exposing the vulnerable redistribution layer to mechanical stress or etching damage.
Solution Approach 2:
The etch stop layer is formed in advance before the redistribution layer is fully integrated, creating a protective barrier that will later prevent damage during the debonding process. This preliminary action ensures that when the carrier substrate needs to be removed, the redistribution layer is already protected by the etch stop layer, eliminating the need for delicate manual handling or complex protective measures during debonding.
2Length of moving object
If the package thickness is reduced to meet consumer demand, then electronic devices become thinner, but the structural integrity and protection of internal layers become more difficult to maintain
Solution Approach 1:
The etch stop layer provides localized protection at the critical interface between the carrier substrate and the redistribution layer. Rather than requiring uniform thickening of the entire package, this layer applies targeted structural reinforcement exactly where the redistribution layer is most vulnerable during the debonding process, enabling thin package design while maintaining local structural integrity.
Data Source
AI summary
A method for fabricating a semiconductor package includes forming a release layer on a first carrier substrate. An etch stop layer is formed on the release layer. A first redistribution layer is formed on the etch stop layer and includes a plurality of first wires and a first insulation layer surrounding the plurality of first wires. A first semiconductor chip is formed on the first redistribution layer. A solder ball is formed between the first redistribution layer and the first semiconductor chip. A second carrier substrate is formed on the first semiconductor chip. The first carrier substrate, the release layer, and the etch stop layer are removed. The second carrier substrate is removed.