Segmented Wire Bonding for Compact Semiconductor Pads
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Solution Overview
Problem
Conventional wire bonding methods for semiconductor devices require larger pad portions for secure bonding, which hinders the size reduction of semiconductor devices due to increased size requirements.
Innovation Solution
A wire bonding structure with a first bonding portion bonded to a semiconductor element and a second bonding portion bonded to a lead, where the first bonding portion includes a front bond, a rear bond, and an intermediate portion, with the second bonding portion being smaller in length, and a bonding tool with a wedge having a gap between its pressing surfaces to facilitate size reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wedge is made large to ensure secure bonding of the wire to the electrode pad, then the bonding reliability is improved, but the pad portion size must be increased which hinders the size reduction of the semiconductor device
Solution Approach 1:
The bonding portion is segmented into a front bond portion and a rear bond portion, with the front bond portion having a larger bonding area than the rear bond portion. This segmentation allows the wire to be securely bonded to the electrode pad through the larger front bond portion, while the smaller rear bond portion suffices for bonding to the lead pad, thereby reducing the required pad portion size without compromising bonding reliability
Solution Approach 2:
Different portions of the wire bonding structure are given different bonding areas according to their functional requirements. The front bond portion is designed with a larger bonding area to ensure secure connection to the electrode pad, while the rear bond portion has a smaller bonding area suitable for connection to the lead pad. This local differentiation of bonding quality allows size reduction of the pad portion while maintaining necessary bonding reliability
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 approach allows for a smaller size semiconductor device by reducing the length of the second bonding portion, enabling a more compact design while maintaining sufficient bonding area, and simplifies the bonding process with adjustable intermediate portion deformation and precise cutting.
Implementation Method 1
The wedge 91 applies ultrasonic vibration under pressure to the wire 96 sandwiched between the end of the wedge 91 and a bonding target, whereby the wire 96 and the bonding target are bonded together
Data Source
AI summary
A wire bonding structure is provided which includes a wire having a first bonding portion and a second bonding portion. The first bonding portion is bonded to an electrode pad of a semiconductor element, whereas the second bonding portion is bonded to a pad portion of a lead. The first bonding portion includes a front bond portion, a rear bond portion, and an intermediate portion sandwiched between these two bond portions. The front bond portion and the rear bond portion are bonded to the electrode pad more strongly than the intermediate portion is. In the longitudinal direction of the wire, the second bonding portion is smaller than the first bonding portion in bonding length.