Polyimide RDL Dielectric for Filling Molding Pits in PoP Packaging
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Solution Overview
Problem
The semiconductor industry faces challenges in achieving high integration density and efficient packaging of semiconductor dies due to limitations in current packaging techniques, particularly in Package-on-Package (PoP) technology, where molding pits can induce defects and reduce production yield.
Innovation Solution
The use of a polyimide dielectric material with specific solvents, cross-linkers, and photosensitizers in a polymer material for forming redistribution layers (RDLs) in semiconductor packages, which fills molding pits and reduces RDL bridging, thereby enhancing packaging efficiency and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional packaging techniques are used, then manufacturing process is simple, but molding pits induce defects and reduce production yield
Solution Approach 1:
The patent converts the harmful molding pits into beneficial features by filling them with conductive material to form via holes that provide electrical interconnections. This transforms the defects into functional elements of the packaging structure, eliminating yield loss while maintaining process simplicity
Solution Approach 2:
The patent introduces an intermediary material (conductive paste or electroplated material) that fills the molding pits and creates via holes. This intermediary serves as both a defect filler and an electrical connection pathway, resolving the conflict between maintaining simple packaging processes and achieving high reliability
2Manufacturing precision
If RDL features are formed with conventional materials, then manufacturing is easier, but resolution of RDL features is lower
Solution Approach 1:
The patent changes the material parameters of the RDL formation process by using low-viscosity conductive paste and controlling the drying/curing parameters. This enables higher resolution features to be formed while maintaining ease of manufacture through screen printing or dispensing techniques
3Reliability
If high curing temperature is used, then polymer material cures completely, but thermal budget increases and causes yield loss
Solution Approach 1:
The patent utilizes phase transition of the polymer material by selecting materials that cure at low temperatures through controlled chemical reactions. The polymer precursor undergoes a phase transition from liquid to solid at temperatures below 150°C, achieving complete curing without thermal damage to sensitive devices
Solution Approach 2:
The patent changes the chemical composition parameters of the polymer material to enable low-temperature curing. By selecting specific polymer precursors and additives, the curing temperature is reduced from conventional high temperatures to below 150°C, eliminating thermal budget issues while ensuring complete curing and high device reliability
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 approach improves the resolution of RDL features, reduces curing temperature, and lowers thermal budget, resulting in increased production throughput and device reliability by minimizing yield loss from defects such as broken RDL lines.
Implementation Method 1
The polymer material includes a polymer precursor, a photosensitizer, and a solvent; patterning the polymer material; and curing the polymer material
Implementation Method 2
which fills molding pits and reduces RDL bridging
Data Source
AI summary
A method of manufacturing a semiconductor device includes forming a polymer mixture over a substrate, curing the polymer mixture to form a polymer material, and patterning the polymer material. The polymer mixture includes a polymer precursor, a photosensitizer, a cross-linker, and a solvent. The polymer precursor may be a polyamic acid ester. The cross-linker may be tetraethylene glycol dimethacrylate. The photosensitizer includes 4-phenyl-2-(piperazin-1-yl)thiazole. The mixture may further include an additive.