Semiconductor Leadframe Step Surface Adhesion
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Solution Overview
Problem
Semiconductor devices with stepped leadframes and resin encapsulation face issues with insufficient adhesion between the resin and the leadframe, leading to delamination and potential moisture ingress, which can cause device failure.
Innovation Solution
The semiconductor device incorporates a leadframe with stepped parts featuring an uneven surface area, where the lower surface of the leadframe is depressed to form a step surface covered with resin, increasing the contact area and adhesion between the leadframe and resin, and includes an uneven surface part with fine depressions to enhance anchoring and prevent delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the lower surface of the leadframe is made flat, then the manufacturing process is simple, but the adhesion between resin and leadframe is insufficient leading to delamination
Solution Approach 1:
The invention transitions from a flat two-dimensional surface to a three-dimensional stepped structure with multiple levels. The leadframe lower surface is formed with stepped parts having different height levels, creating vertical dimensionality that increases the resin contact area and improves adhesion through mechanical interlocking, while resolving the contradiction between simple manufacturing and strong adhesion.
Solution Approach 2:
The leadframe lower surface is segmented into multiple stepped levels rather than being a single flat surface. This segmentation creates multiple terraces that increase the total surface area available for resin adhesion, allowing the resin to anchor at different heights and preventing delamination while maintaining manufacturing feasibility.
2Strength
If the contact area between resin and leadframe is increased, then adhesion is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The invention applies local quality by creating stepped parts with different surface characteristics at specific locations on the leadframe. The stepped structure concentrates the adhesion enhancement at particular areas rather than requiring uniform high precision across the entire surface, allowing resin to anchor effectively at the stepped regions while reducing overall manufacturing precision requirements.
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 design significantly increases the adhesion between the leadframe and resin, preventing delamination and moisture ingress, thereby enhancing the reliability and durability of the semiconductor device.
Implementation Method 1
an encapsulation resin encapsulating the leadframe and the semiconductor chip
Implementation Method 2
A part of the second surface is depressed toward the first surface to form a step surface. The step surface includes an uneven surface part where depressions are formed, and is covered with the encapsulation resin
Data Source
AI summary
A semiconductor device includes a leadframe, a semiconductor chip, and an encapsulation resin encapsulating the leadframe and the semiconductor chip. The leadframe includes a first surface and a second surface facing away from the first surface. The semiconductor chip is mounted on the first surface of the leadframe. A part of the second surface of the leadframe is depressed toward the first surface to form a step surface. The step surface includes an uneven surface part where depressions are formed, and is covered with the encapsulation resin.