Semiconductor Pad Structure for Encapsulation Peeling Resistance
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Solution Overview
Problem
Existing semiconductor devices face issues with peeling and cracking at the interface between the encapsulating body and the protective film due to thermal stress, leading to degraded connection and insulation reliability.
Innovation Solution
The semiconductor device incorporates a protective film with openings exposing the pad surface, where the pad has a protruded portion with a 90-degree angle relative to the peripheral area, preventing peeling progression and maintaining connection reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the encapsulating body directly contacts the protective film, then the sealing and protection function is improved, but peeling and cracking occur due to thermal stress
Solution Approach 1:
The pad structure serves as an intermediary element between the encapsulating body and the protective film. The pad includes a connection area with a first surface and a peripheral area with a second surface that defines a relative angle of 90 degrees or less, creating a stepped configuration that acts as a mechanical buffer to absorb thermal stress and prevent peeling propagation at the interface.
2Area of stationary object
If the pad surface is fully exposed, then the bonding wire connection area is increased, but the pad becomes more vulnerable to peeling progression
Solution Approach 1:
The pad surface is segmented into two distinct functional areas: a connection area (first surface) for bonding wire attachment and a peripheral area (second surface) for peeling resistance. The peripheral area is positioned at the edge of the pad and forms a stepped structure with the connection area, creating a geometric barrier that stops peeling progression while preserving the connection area for electrical bonding.
3Reliability
If the protective film covers the entire pad, then the pad is protected, but the bonding wire cannot be connected to the pad
Solution Approach 1:
The protective film is selectively removed or opened at the pad location to expose the pad surface. This extraction of the protective film coverage at the specific pad area allows the bonding wire to make direct contact with the pad for electrical connection, while the protective film remains intact in other areas to provide continued protection to the semiconductor element.
Data Source
AI summary
In a semiconductor device, a first wiring member is electrically connected to a first main electrode on a first surface of a semiconductor element, and a second wiring member is electrically connected to a second main electrode on a second surface of the semiconductor element. An encapsulating body encapsulates at least a part of each of the first and second wiring members, the semiconductor element and a bonding wire. The semiconductor element has a protective film on the first surface of the semiconductor substrate, and the pad has an exposed surface exposed from an opening of the protective film. The exposed surface includes a connection area to which the bonding wire is connected, and a peripheral area on a periphery of the connection area. The peripheral area has a surface that defines an angle of 90 degrees or less relative to a surface of the connection area.