Semiconductor Case Recess for Bonding Material
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Solution Overview
Problem
The reliability of semiconductor devices is compromised due to uneven adhesive application between the printed-circuit board and the case, leading to air interposition and vibration during bonding wire attachment, resulting in bonding failures.
Innovation Solution
A semiconductor device design featuring a circuit board with an insulating layer and a housing that includes a recessed area for bonding material, ensuring reliable bonding by eliminating air gaps and stabilizing the electrode pad during ultrasonic bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesive is applied between the printed-circuit board and the case, then the circuit board is fixed to the case, but the adhesive application may be uneven causing air gaps and bonding failures
Solution Approach 1:
A recess is formed in advance in the case at the position corresponding to the electrode pad. This preliminary structural preparation ensures that when adhesive is applied, it will be contained within the recess, preventing air gaps and ensuring uniform bonding without requiring high precision in adhesive application.
Solution Approach 2:
The recess is specifically formed only at the local area corresponding to the electrode pad, not across the entire bonding surface. This localized modification provides targeted improvement where it is most needed (under the electrode pad) while maintaining simplicity and avoiding unnecessary complexity in other areas.
2Strength
If adhesive is applied to bond the circuit board to the case, then the board is fixed, but air may be interposed under the electrode pad causing vibration during bonding
Solution Approach 1:
The harmful air layer is extracted or removed from the bonding interface by providing a recess that actively captures and contains the adhesive, ensuring complete displacement of air from the critical bonding area under the electrode pad.
Solution Approach 2:
The recess structure is prepared in advance to prevent air interposition before bonding occurs. The pre-formed cavity ensures that adhesive flows into and fills the space, eliminating air gaps proactively rather than attempting to remove them after bonding.
3Reliability
If adhesive is applied unevenly, then bonding may fail, but increasing adhesive amount increases complexity of control
Solution Approach 1:
The recess structure enables self-regulating adhesive application. The recess automatically controls the adhesive amount and distribution through its physical boundaries, eliminating the need for complex external control systems. The adhesive naturally fills the recess, providing self-contained, reliable bonding without requiring precise control mechanisms.
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 solution ensures reliable bonding of the bonding wire to the electrode pad, enhancing the semiconductor device's reliability and preventing electrical failures by burying bonding material in recessed areas, thus stabilizing the electrode pad and preventing protrusion.
Implementation Method 1
the electrode pad also vibrates when a bonding wire is bonded to the electrode pad by ultrasonic vibration
Data Source
AI summary
A semiconductor device includes a circuit board including an insulating layer having opposite front and rear surfaces, an electrode pad disposed on the front surface, a housing having an installation area for the circuit board, and a bonding material embedded in a recess within either a first area located at the rear surface of the insulating layer directly below an area of the circuit board in which the electrode pad is disposed, or at a second area located within the installation area of the housing and corresponding to the first area in a plan view.