Stackable Semiconductor Package Supporting Element
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Solution Overview
Problem
Existing stackable semiconductor packages face issues with the overhang portion of the second substrate shaking, swaying, or cracking during wire bonding, limiting the layout space and thickness reduction due to excessive stress and restricted overhang length.
Innovation Solution
Incorporation of a supporting element, such as a dummy bump, between the first and second substrates to stabilize the second substrate during wire bonding, allowing for increased layout space and reduced thickness by preventing shaking and cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the overhang portion of the second substrate is extended beyond the chip edge to increase layout space, then the area for placing second bonding pads is increased, but the overhang portion shakes or sways during wire bonding when the overhanging length exceeds three times the substrate thickness
Solution Approach 1:
A supporting element (dummy bump or pillar) is introduced as an intermediary between the first substrate and the second substrate to provide mechanical support to the overhang portion. This mediator prevents shaking and swaying during wire bonding while allowing the overhang to extend beyond the chip edge, thus resolving the contradiction between increasing layout space and maintaining stability.
2Length of moving object
If the second substrate is made thinner to reduce the whole package thickness, then the overall package size is reduced, but the substrate becomes more prone to cracking under stress during wire bonding
Solution Approach 1:
The supporting element acts as a mediator that distributes and bears the stress during wire bonding, allowing the second substrate to be made thinner without compromising its stress resistance. The supporting element absorbs the mechanical load, preventing cracking in the thin substrate while enabling reduced package thickness.
3Stability of the object's composition
If the overhanging length is limited to prevent shaking and cracking, then substrate stability is maintained, but the layout space for second bonding pads is restricted
Solution Approach 1:
The supporting element serves as a mediator that enables the overhang portion to extend further from the chip edge without experiencing harmful shaking or cracking. By providing mechanical support at the support position, the intermediary allows greater overhanging length and consequently larger layout space for bonding pads while maintaining stability through the supported structure.
Data Source
AI summary
The present invention relates to a stackable semiconductor package, comprising a first substrate, a chip, a second substrate, a plurality of second wires, a plurality of supporting elements and a molding compound. The chip is disposed on and electrically connected to the first substrate. The second substrate is disposed above the chip, and the area of the second substrate is larger than that of the chip. The second substrate is electrically connected to the first substrate by the second wires. The supporting elements are disposed between the first substrate and the second substrate, and are used for supporting the second substrate. The molding compound encapsulates the first surface of the first substrate, the chip, the second wires, the supporting elements and part of the second substrate, and exposes a surface of the second substrate. The overhang portion of the second substrate will not shake or sway during wire bonding process.