Cured Resin Film Cross-Linking for Fine Fan-Out Wiring
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Solution Overview
Problem
In the fan-out package technology, forming fine wiring on a cured resin film is challenging due to metal seed layer penetration, leading to short-circuits and difficulties in removing the metal seed layer between closely spaced wirings, especially with inter-wiring distances of 3 μm or less.
Innovation Solution
A method involving the application of a resin composition onto a substrate, followed by drying and heating to form a cured resin film with a specific cross-linking density of 0.1×10−3 to 110×10−3 mol/cm3, allowing for the formation of metal seed layers and subsequent electrolytic plating to create wiring patterns with widths and inter-wiring distances of 3 μm or less, while enabling complete removal of the metal seed layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a metal seed layer is formed by sputtering on a cured resin film to create fine wiring patterns, then wiring density and transmission speed are improved, but metal penetrates deeply inside the cured resin film causing short-circuits between wirings
Solution Approach 1:
The patent changes the physical and chemical parameters of the cured resin film, specifically setting the cross-linking density to 0.01-10 mmol/L and controlling the glass transition temperature to 150-250°C. These parameter adjustments optimize the resin's resistance to metal penetration while maintaining fine wiring formation capability, preventing short-circuits between closely spaced wirings
Solution Approach 2:
The patent uses a composite resin composition containing specific components: a polyimide resin as the base, a cycloaliphatic epoxy resin for cross-linking, and a photopolymerization initiator. This composite material structure provides both the mechanical properties needed for fine wiring support and the chemical resistance to prevent metal penetration
2Productivity
If the inter-wiring distance is decreased to achieve higher density, then packaging density is improved, but it becomes difficult to remove the metal seed layer between the wirings
Solution Approach 1:
The patent optimizes the cross-linking density parameter to a specific range (0.01-10 mmol/L) that balances metal penetration resistance with etchant accessibility. This controlled cross-linking allows the metal seed layer to be firmly attached during sputtering but still removable by etchants even when wirings are closely spaced at 3 μm or less
Solution Approach 2:
The patent performs preliminary control of the resin film's cross-linking structure before metal seed layer formation. By pre-setting the appropriate cross-linking density and glass transition temperature, the resin film is prepared in advance to allow complete metal seed layer removal after wiring formation, even with minimal inter-wiring distances
3Reliability
If the cross-linking density of the cured resin film is increased to prevent metal penetration, then short-circuit prevention is improved, but warpage of the substrate increases
Solution Approach 1:
The patent identifies and controls multiple interrelated parameters: cross-linking density (0.01-10 mmol/L), glass transition temperature (150-250°C), and resin composition ratios. By optimizing these parameters together rather than independently, the patent achieves sufficient cross-linking to prevent metal penetration while maintaining substrate flatness and minimizing warpage
Solution Approach 2:
The patent employs a composite resin system where the polyimide resin provides structural stability and low warpage characteristics, while the cycloaliphatic epoxy resin contributes to cross-linking density control. This composite approach allows independent optimization of warpage resistance and penetration resistance
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 method effectively prevents short-circuits and ensures complete removal of the metal seed layer, maintaining excellent adhesiveness and reducing warpage, thus enabling the production of semiconductor devices with fine wiring patterns.
Implementation Method 1
a step of applying a resin composition onto a substrate and drying the resin composition to form a resin film
Implementation Method 2
a step of heating the resin film to obtain a cured resin film
Implementation Method 3
a step of forming a metal seed layer by sputtering on a surface of the cured resin film
Implementation Method 4
a step of forming a metal layer having a wiring pattern with a wiring width of 3 μm or less and an inter-wiring distance of 3 μm or less by electrolytic plating
Data Source
AI summary
A semiconductor device production method including: applying a resin composition onto a substrate and drying the resin composition to form a resin film; heating the resin film to obtain a cured resin film; forming a metal seed layer by sputtering on a surface of the cured resin film; forming a resist pattern having an opening portion for forming a wiring pattern on a surface of the metal seed layer; forming a metal layer having a wiring pattern with a wiring width of 3 μm or less and an inter-wiring distance of 3μm or less by electrolytic plating in a region on the surface of the metal seed layer exposed from the resist pattern; removing the resist pattern; and removing the metal seed layer exposed by the removal of the resist pattern, wherein a cross-linking density of the cured resin film is 0.1×10−3 to 110×10−3 mol/cm3.