Semiconductor Package Interface Cavities to Prevent Delamination
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Solution Overview
Problem
Semiconductor packages face delamination issues due to poor adherence between the molding compound and the die pad or leads, leading to potential device failure from liquid or moisture exposure.
Innovation Solution
The implementation of an immersion porous copper adhesion promoter (IPC-AP) process, which embeds microstructures in a copper layer and removes them to create cavities, providing a roughened surface for improved adhesion with encapsulant materials like mold compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a smooth surface is used between the molding compound and die pad or leads, then the manufacturing process is simple, but the adhesion between molding compound and die pad or leads is poor leading to delamination
Solution Approach 1:
The patent applies porous copper adhesion promoter (AP) material between the molding compound and die pad or leads. The porous structure provides increased surface area and mechanical interlocking capability, enabling the molding compound to adhere firmly to the substrate. The porous material acts as an adhesion promoter that prevents delamination while maintaining a relatively simple overall device structure.
Solution Approach 2:
The patent uses a composite structure combining copper adhesion promoter material with the molding compound and substrate. This composite approach creates a multi-layer interface that leverages the adhesive properties of the copper AP material to bond the molding compound to the die pad or leads, resolving the adhesion problem without requiring complex surface treatments.
2Reliability
If the molding compound is adhered to die pad and leads, then delamination is prevented, but manufacturing complexity increases due to additional adhesion promotion processes
Solution Approach 1:
The patent changes the material parameter at the interface by introducing porous copper adhesion promoter material with specific porosity and surface area characteristics. This material parameter change enables effective adhesion between the molding compound and substrate. The process integrates this material application into existing manufacturing workflows, achieving reliable bonding without substantially increasing manufacturing complexity.
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 enhances adhesion and mechanical interlock between the encapsulant and the die pad or leads, reducing or preventing delamination and improving the reliability of semiconductor packages.
Implementation Method 1
The cavities may be formed by an immersion porous copper adhesion promoter (IPC-AP) process, in which microstructures are embedded in a deposited copper layer through an electroless copper plating process.
Implementation Method 2
The microstructures may be removed, for example, by a solvent, and the cavities are formed due to the removal of the microstructures.
Data Source
AI summary
In various embodiments, the present disclosure provides semiconductor devices, packages, and methods. In one embodiment, a device includes a die pad, a lead that is spaced apart from the die pad, and an encapsulant on the die pad and the lead. A plurality of cavities extends into at least one of the die pad or the lead to a depth from a surface of the at least one of the die pad or the lead. The depth is within a range from 0.5 μm to 5 μm. The encapsulant extends into the plurality of cavities. The cavities facilitate improved adhesion between the die pad or lead and the encapsulant, as the cavities increase a surface area of contact with the encapsulant, and further increase a mechanical interlock with the encapsulant, as the cavities may have a rounded or semi-spherical shape.