Flip-Chip Lead Layout for Bonding Stress and State Verification
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Solution Overview
Problem
In conventional semiconductor devices with flip-chip mounted semiconductor elements, the bonding portion between electrodes and leads cannot be directly observed, leading to uncertainty in bonding state verification, and internal stress at the bonding sites near the package corners may cause stress fractures due to inappropriate alignment of terminal sections.
Innovation Solution
The semiconductor device incorporates first conductive sections located between second terminal sections and the semiconductor element, which are insulated from the circuit section, allowing for reduced internal stress at electrode bonding sites and enabling verification of bonding states through resistance measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the semiconductor element is flip-chip mounted on the lead with terminal sections aligned perpendicular to the thickness direction, then the electrode alignment is simplified and manufacturing is easier, but the bonding portion cannot be directly observed and internal stress causes reliability issues
Solution Approach 1:
A resin layer is introduced as an intermediary substance between the lead and the semiconductor element. This resin layer fills the space around the electrodes and bonding portions, providing mechanical support and stress distribution. The resin acts as a mediator that protects the bonding portions from stress concentration while maintaining the flip-chip mounting configuration, thus improving reliability without compromising ease of manufacture.
Solution Approach 2:
The resin layer is applied beforehand to cover and protect the bonding portions before the semiconductor element is fully mounted. This pre-cushioning approach distributes internal stresses away from the vulnerable bonding areas, preventing stress fractures and enhancing bonding reliability while maintaining the simplified terminal section alignment.
2Device complexity
If the terminal sections are aligned in a direction perpendicular to the thickness direction of the lead, then the electrode arrangement is simplified, but the bonding state cannot be verified and stress concentration occurs at corner electrodes
Solution Approach 1:
The resin layer serves as an intermediary that covers the bonding portions and electrodes, creating a protective encapsulation. This allows the simplified perpendicular alignment of terminal sections to be maintained while the resin provides stress distribution and protection, preventing the reliability issues that would otherwise result from the alignment configuration.
Solution Approach 2:
The resin layer forms a flexible protective shell around the bonding portions and electrodes. This thin film structure conforms to the underlying components while providing mechanical protection and stress distribution, allowing the device to maintain the simplified terminal alignment without suffering from stress concentration at corner electrodes.
3Area of stationary object
If the electrode is located outermost in the alignment direction of terminal sections, then the package layout is compact, but the bonding portion experiences maximum internal stress and may fracture
Solution Approach 1:
The resin layer acts as an intermediary protective layer that covers the outermost electrodes and their bonding portions. This intermediary structure distributes the internal stress away from the electrode-bonding interfaces, preventing stress concentration and potential fracture while maintaining the compact package layout achieved by the outermost electrode positioning.
Solution Approach 2:
The resin layer is applied as a pre-cushioning protective layer that envelops the bonding portions of outermost electrodes before stress concentration can occur. This beforehand protection maintains the compact package area while preventing strength degradation through stress distribution.
Data Source
AI summary
A semiconductor device includes a lead, a semiconductor element, a sealing resin, and a first conductive section. The lead includes an obverse surface facing in a thickness direction. The semiconductor element includes a circuit section, an element first surface, and first electrodes on the element first surface. The first electrodes are connected to the obverse surface. The sealing resin covers the lead partially and the semiconductor element. The lead includes first terminal sections and a second terminal section aligned in a first direction crossing the thickness direction. Each first electrode is electrically connected to the circuit section. Each first terminal section is electrically connected to the circuit section via one first electrode. The first conductive section is between the second terminal section and the element first surface and connected to the second terminal section and the element first surface. The first conductive section is insulated from the circuit section.