Semiconductor Wire Asymmetric Bending for Encapsulation Pitch
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Solution Overview
Problem
Conventional semiconductor devices face challenges in maintaining the interval between fine metal wires during encapsulation, leading to potential contact and exposure on the package surface due to resin encapsulant deformation, which limits pitch reduction and increases manufacturing costs.
Innovation Solution
The semiconductor device employs fine metal wires with distinct bend shapes, where one wire has a slope extending upwardly and the other downwardly, with strategically located bending points to maintain sufficient interval and prevent contact, allowing for pitch reduction and flexible encapsulation conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fine metal wires with conventional trapezoidal bend shapes are used to connect electrodes to inner leads, then the pitch between adjacent wires can be maintained sufficiently large, but the wires may come into contact with one another during resin encapsulation due to deformation
Solution Approach 1:
The patent applies asymmetry by designing the fine metal wires with different bend shapes - specifically, alternating between upward-sloping and downward-sloping configurations. This asymmetric design ensures that during resin encapsulation, the wires deform in opposite directions, preventing them from coming into contact with each other while maintaining sufficient pitch between adjacent wires.
Solution Approach 2:
The patent inverts the conventional approach by using wires with opposite slope directions instead of uniform trapezoidal shapes. By alternating the slope directions (upward for one wire, downward for the next), the wires are positioned to move away from each other during encapsulation rather than toward each other, effectively preventing contact.
2Productivity
If the pitch between fine metal wires is reduced to achieve higher density, then more electrodes can be connected in a smaller area, but the wires are more likely to come into contact during encapsulation
Solution Approach 1:
The asymmetric bend shape design with alternating upward and downward slopes creates a mechanical interlocking effect that maintains wire separation even at reduced pitch. The opposite slope directions ensure that when wires deform during encapsulation, they move in opposite directions, preventing contact despite the smaller spacing between adjacent wires.
Solution Approach 2:
The patent applies preliminary anti-action by pre-configuring the wires with opposite slope directions before encapsulation. This preliminary configuration creates a counterbalancing effect that anticipates and prevents the harmful deformation that would otherwise cause wire contact during the encapsulation process.
3Ease of manufacture
If conventional fine metal wire structures are used, then manufacturing is simpler, but the range of encapsulation conditions is limited and wires may be exposed on the package surface
Solution Approach 1:
The asymmetric wire design with alternating slopes provides built-in protection against wire exposure during encapsulation. The opposite slope directions create a self-regulating configuration that adapts to various encapsulation conditions, allowing the wires to maintain proper positioning and prevent exposure on the package surface across a broader range of manufacturing parameters.
Data Source
AI summary
A semiconductor device includes a plurality of electrodes formed on a semiconductor chip, and a plurality of wires each connecting each of the electrodes to an inner lead, and each having a plurality of bending points. A first wire of the plurality of the wires has a slope extending upwardly from a first bending point toward a second bending point, where the first bending point is being located at an upper end of a rising portion. The second bending point of the first wire is the highest bending point in the first wire. A second wire of the plurality of the wires has a slope extending downwardly from a first bending point toward a second bending point, where the first bending point is located at an upper end of a rising portion. The second bending point of the second wire is the lowest bending point in the second wire.