Semiconductor Fuse with Bent Lead-out Wiring for Voltage Stability
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Solution Overview
Problem
The crack assist type process for cutting off electric fuses requires a higher application voltage, which is susceptible to variation due to current deviations and process variations, resulting in a narrow allowable range for preventing cut-off defects, particularly when the application voltage is decreased, due to heat radiation from large area wiring acting as a heat sink.
Innovation Solution
A semiconductor device configuration with first and second large area wirings and lead-out wirings having a bent pattern, extending the current path from the large area wiring to the fuse unit, preventing heat radiation and allowing for a wider range of application voltage variation without increasing the device area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the crack assist type process is used to cut off the electric fuse, then the probability of reconnection is reduced and cut-off state is maintained, but the application voltage must be increased which narrows the allowable voltage range due to heat radiation from large area wiring
Solution Approach 1:
The patent divides the fuse structure into multiple segments including a via portion and wire portions across different layers. The cut-off is specifically targeted at the via portion where material flow-out occurs, separating the cut-off function from the entire fuse path. This segmentation allows the crack assist process to work effectively at specific locations without requiring excessive voltage that would be affected by heat radiation from large area wirings.
Solution Approach 2:
The patent applies different structural characteristics to different parts of the fuse. The via portion has a specific structure that promotes material flow-out during crack assist cutting, while the wire portions in different layers have optimized dimensions and arrangements. This local differentiation enables reliable cut-off at the via portion without requiring high voltage that would be sensitive to heat radiation effects.
2Reliability
If the application voltage is increased for crack assist cutting, then the fuse can be cut off reliably, but the system becomes more sensitive to voltage variation from current deviation and process variation
Solution Approach 1:
The patent structures the fuse with pre-defined material flow paths and concentrated regions before the cutting process. The via portion is designed with specific dimensions and material distribution that prepare it for controlled material flow-out during crack assist cutting. This preliminary structuring enables reliable cut-off at lower voltages, reducing sensitivity to voltage variations from current and process deviations.
Solution Approach 2:
The patent optimizes the physical parameters of the via portion including its dimensions, material composition, and structural configuration. By changing these parameters, the via portion becomes more susceptible to crack assist cutting at lower voltages, thereby reducing the operating voltage requirement and its sensitivity to manufacturing variations.
3Power
If large area wiring is used to apply voltage to the fuse, then sufficient current can be supplied, but the wiring acts as a heat sink that radiates heat and reduces the allowable voltage range
Solution Approach 1:
The patent extracts the critical cutting function from the entire fuse path and concentrates it at the via portion. By designing the via portion with specific structural characteristics that promote material flow-out, the cut-off process is localized to this region. This extraction allows the large area wiring to supply sufficient current without its heat radiation significantly affecting the cut-off process, since the critical event occurs at the via portion rather than along the entire wire path.
Solution Approach 2:
The patent utilizes a multi-layer structure with vias connecting different layers to create a three-dimensional fuse configuration. The via portion acts as a localized cutting point in the vertical dimension, separating the cut-off function from the planar wire portions. This dimensional change allows the large area wiring to maintain low resistance for power supply while the via portion provides a localized, temperature-insensitive cutting point.
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 configuration effectively widens the allowable range of application voltage variation while maintaining a stable cut-off state without increasing the device area, enhancing robustness against current deviations and process variations.
Implementation Method 1
extending the current path from the large area wiring to the fuse unit, preventing heat radiation
Data Source
AI summary
A semiconductor device includes an electric fuse and first and second large area wirings for applying a voltage to the electric fuse. The electric fuse includes a fuse unit which includes an upper-layer fuse wiring, a lower-layer fuse wiring, and a via connecting the upper-layer fuse wiring and the lower-layer fuse wiring, an upper-layer lead-out wiring which connects the upper-layer fuse wiring and the first large area wiring and has a bent pattern, and a lower-layer lead-out wiring which connects the lower-layer fuse wiring and the second large area wiring and has a bent pattern.