Semiconductor Encapsulation Epoxy for Selective LDS Metal Plating
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Solution Overview
Problem
Conventional epoxy resin compositions for semiconductor encapsulation face challenges in achieving superior curability and enabling selective metal plating on the surface or inside the cured product, particularly when using laser direct structuring (LDS) additives.
Innovation Solution
The use of a curing accelerator with a urea structure in an LDS additive-containing epoxy resin composition prevents cure inhibition and allows for the formation of a plated layer only in parts irradiated with a laser, thereby enhancing curability and enabling selective plating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a Lewis acidic LDS additive is added to an epoxy resin composition containing a basic curing accelerator, then laser direct structuring capability is provided, but curability is significantly impaired due to catalytic activity inhibition
Solution Approach 1:
The patent uses a silane coupling agent as an intermediary substance that coats the surface of the Lewis acidic LDS additive particles. This coating layer prevents direct contact between the additive and the basic curing accelerator, thereby eliminating the catalytic activity inhibition while preserving the laser direct structuring capability of the additive.
Solution Approach 2:
The LDS additive particles are pre-coated with silane coupling agent before being added to the epoxy resin composition. This preliminary coating action ensures that when the curing accelerator is subsequently added, it cannot directly interact with the Lewis acidic additive, thus preventing curability impairment from the outset.
2Reliability
If the surface of LDS additive is coated with silane coupling agent to prevent cure inhibition, then curability is improved, but laser activation is inhibited
Solution Approach 1:
The patent carefully controls the coating parameters including the type of silane coupling agent, coating thickness, and curing conditions. By optimizing these parameters, the coating provides sufficient protection against catalytic inhibition while remaining thin enough to allow laser penetration and activation of the LDS additive core.
Solution Approach 2:
The silane coupling agent coating provides localized protection only at the particle surface where contact with curing accelerator occurs, while the internal core of the LDS additive retains its full laser activation capability. This creates a differentiated structure with different functional properties at different locations of the same particle.
3Reliability
If sputtering method is used to deposit metal layer for electromagnetic shielding, then shielding property is achieved, but continuous production is impossible due to high-vacuum requirement
Solution Approach 1:
The patent replaces the mechanical vacuum-based sputtering deposition system with a chemical electroless plating system. This substitution eliminates the need for high-vacuum conditions while achieving the same metal layer deposition function, thereby enabling continuous production in atmospheric conditions.
Solution Approach 2:
The electroless plating process is self-catalyzed by the laser-activated LDS additive on the encapsulation material surface. The additive itself serves as the catalyst for metal deposition, eliminating the need for external vacuum equipment and complex process control systems required by sputtering.
4Manufacturing precision
If electrolytic copper plating is used for rewiring layer formation, then high-density wiring is achieved, but significantly cumbersome steps are required including resist application, pattern formation, washing, sputtering, resist removal and electrolytic plating
Solution Approach 1:
The patent extracts and eliminates the resist application, pattern formation, and resist removal steps from the conventional electrolytic plating process. By using laser direct structuring to pre-activate only the desired pattern areas on the encapsulation material, metal plating is selectively deposited only where needed, eliminating the need for resist processing steps.
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 proposed epoxy resin composition exhibits superior curability and allows for easy and selective formation of metal layers on the surface or inside the cured product, making it suitable for small and thin communication devices, antenna-equipped semiconductor devices, and those requiring wiring layers, while also enabling continuous production and improved productivity.
Implementation Method 1
by adding an LDS additive to a resin, and then using a laser to activate the surface of or the inner region of a cured product of the resin, a plated layer(s) can be formed only in parts that have been irradiated with the laser
Implementation Method 2
a method for forming rewiring, electrolytic copper plating or the like is now dominant
Data Source
AI summary
Provided are an epoxy resin composition for semiconductor encapsulation; and a semiconductor device having a cured product of such composition. The composition has a superior curability, and a metal layer (plated layer) can be selectively and easily formed on the surface of or inside the cured product of this composition via an electroless plating treatment. The composition of the present invention contains:(A) an epoxy resin;(B) a phenolic curing agent;(C) a curing accelerator having a urea structure;(D) a laser direct structuring additive; and(E) an inorganic filler.