FOPLP Redistribution Layer Protection During Conductive Pad Cleaning
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Solution Overview
Problem
The conventional fan-out panel level package (FOPLP) technology faces issues with over-etching of the dielectric layer during cleaning and etching processes, leading to damage of the redistribution layer and affecting the package device's characteristics.
Innovation Solution
A manufacturing method for a package device that includes forming a protecting layer to fully cover the release layer before forming the redistribution layer, which protects the redistribution layer from damage during cleaning and etching processes, ensuring effective cleaning of the conductive pads and improving solder ball adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the conventional FOPLP method is used without a protecting layer, then the cleaning process can access the conductive pads, but the dielectric layer of the redistribution layer is over-etched and damaged
Solution Approach 1:
A protecting layer is introduced as an intermediary between the cleaning/etching process and the redistribution layer. This protecting layer selectively protects the dielectric layer of the redistribution layer from over-etching while allowing the cleaning process to effectively clean the conductive pads through exposed regions or selective permeability.
Solution Approach 2:
The protecting layer is applied with local quality differentiation - it covers and protects the dielectric layer regions that are vulnerable to over-etching, while leaving the conductive pad regions accessible for effective cleaning. This selective protection approach ensures both the integrity of the redistribution layer and the effectiveness of the cleaning process.
2Reliability
If the dielectric layer is exposed during cleaning process, then cleaning can reach conductive pads, but the dielectric layer is easily over-etched causing damage
Solution Approach 1:
The protecting layer is applied in advance before the cleaning and etching processes to prevent over-etching damage to the dielectric layer. This preliminary protective action ensures that the dielectric layer maintains its structural integrity while still allowing the cleaning process to effectively prepare the conductive pads for solder ball bonding.
3Manufacturing precision
If a protecting layer is added to protect the redistribution layer, then over-etching is prevented, but the cleaning process effectiveness may be reduced
Solution Approach 1:
The protecting layer is designed with local quality variations - it provides full protection over the dielectric layer regions while having controlled accessibility over the conductive pad regions. This allows the cleaning process to be effective on the conductive pads without compromising the protection of the vulnerable dielectric layer.
Solution Approach 2:
The protecting layer serves as a smart intermediary that mediates between the cleaning process and the redistribution layer. It selectively allows cleaning agents to reach the conductive pads while blocking protection to the dielectric layer, thus resolving the contradiction between protection and cleaning effectiveness.
Data Source
AI summary
A manufacturing method of a package device is provided. First, a carrier is provided, and then a conductive element is formed on the carrier. Thereafter, a conductive pad is formed on the conductive element. Next, a redistribution layer is formed on the conductive pad. Then, the carrier and at least a part of the conductive element are removed.