Engraved Patterns on Semiconductor Package Clips and Lead Frames
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Solution Overview
Problem
The existing semiconductor packages face issues with low adhesive forces between components, leading to separation and internal corrosion due to micro-moisture penetration, which compromises electrical quality and reliability.
Innovation Solution
The implementation of finely engraved patterns on the metal surfaces of components such as clips, lead frames, and substrates, featuring V or U shapes, diamond-shaped lattice patterns, and other designs, which increase the surface roughness and prevent moisture ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal components (clip, lead frame, substrate) are used in semiconductor packages, then electrical conductivity and structural strength are improved, but adhesive force with sealing material decreases and internal corrosion increases due to low adhesion
Solution Approach 1:
The patent applies different surface treatments to different regions of the metal components. Specifically, the outer peripheral surfaces of the lead frame and substrate are treated to enhance adhesion with sealing material, while the bonding surfaces for chip attachment maintain their original properties. This localized differentiation resolves the contradiction by improving adhesion where needed without compromising electrical or bonding performance elsewhere.
Solution Approach 2:
The patent implements surface treatments (such as plating with nickel, palladium, or other adhesive-enhancing coatings) on metal components before assembly into the semiconductor package. This preliminary action of pre-treating the surfaces ensures that when the sealing material is later applied, strong adhesion is achieved, preventing both separation and moisture penetration that would cause corrosion.
2Strength
If smooth metal surfaces are used for components, then manufacturing simplicity is maintained, but adhesive force with sealing material and solder is insufficient causing separation
Solution Approach 1:
The patent changes the surface parameters of metal components by applying thin coating layers (such as nickel plating of 0.1-1.0 μm or palladium plating of 0.05-0.5 μm) or surface roughening treatments. These parameter changes in surface composition and texture significantly improve adhesive force while the thin nature of the treatments keeps manufacturing complexity and cost relatively low.
Solution Approach 2:
The patent creates composite surface structures by combining base metal materials (copper, aluminum, or their alloys) with adhesive-enhancing coating materials (nickel, palladium, tin, or surface roughening layers). This composite approach allows the bulk material to maintain its electrical and mechanical properties while the surface layer provides enhanced adhesion for sealing material and solder attachment.
3Reliability
If metal components are sealed with epoxy molding compound, then structural protection is provided, but micro-moisture penetration occurs along metal surfaces causing internal corrosion
Solution Approach 1:
The patent applies surface treatments to metal components before sealing to create hydrophobic or adhesive-enhancing surfaces that prevent moisture from establishing capillary pathways. This preliminary surface modification creates a barrier that blocks moisture penetration even when the sealing material has micro-defects, thereby preventing internal corrosion.
Solution Approach 2:
The patent acknowledges that metal surfaces naturally create pathways for moisture penetration, but converts this harmful effect into a benefit by applying surface treatments that make the metal surfaces themselves become part of the moisture barrier system. The treated surfaces create tortuous paths and reduce surface energy, transforming the metal-from-harmful-conduit into a protective element of the sealing system.
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 engraved patterns enhance adhesive forces between the sealing material and components, preventing micro-moisture penetration and thus improving the electrical quality and reliability of semiconductor packages by increasing the contact area and altering the path for moisture penetration.
Implementation Method 1
having finely engraved patterns formed on metal surface thereof
Implementation Method 2
preventing micro-moisture penetration from the outside of the semiconductor package
Data Source
AI summary
Provided is a semiconductor package. More particularly, the present invention relates to a clip, a lead frame, and a substrate used in a semiconductor package having engraved patterns formed on surfaces thereof so as to increase an adhesive force and a corrosion resistant performance, thereby improving reliability of the semiconductor package, and the semiconductor package including the same.