MIM Bond Wire Stabilization in Low-Height Memory Packages
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Solution Overview
Problem
The challenge of reducing the size of semiconductor packages without sacrificing capacity, stability, and reliability is exacerbated by the movement and disconnection of bond wires, which are not adequately secured by conventional encapsulation methods, leading to issues like wire sagging and crossing.
Innovation Solution
Incorporating a multifunctional interface material (MIM) structure with an adhesive layer that secures bond wires within the semiconductor package, supported by a polymer layer to prevent excessive movement and enhance stability, while maintaining a reduced overall height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If additional memory dies are added to increase capacity, then the storage capacity increases, but the package height increases and bond wire reliability deteriorates
Solution Approach 1:
The patent transitions from vertical stacking (increasing height) to lateral expansion (increasing footprint area) by arranging memory dies in a planar grid pattern rather than stacking them vertically. This dimensional change allows capacity increase without proportionally increasing package height, thereby maintaining bond wire reliability while achieving higher storage capacity.
2Quantity of substance
If additional memory dies are added to increase capacity, then the storage capacity increases, but bond wire stability deteriorates due to increased risk of crossing and disconnection
Solution Approach 1:
By arranging dies laterally in a grid rather than stacking vertically, the patent reduces the number of bond wires required and minimizes wire crossings, thereby improving bond wire reliability while still increasing capacity through lateral expansion.
3Object-affected harmful factors
If epoxy-resin encapsulation is used to protect bond wires, then the package is protected, but the bond wires become unstable and prone to movement and disconnection
Solution Approach 1:
The patent applies a release agent to the mold cavity walls before encapsulation, creating a non-stick surface that prevents the molding compound from adhering to and stressing the bond wires during the encapsulation process. This preliminary action protects the bond wires from disconnection and sagging while still providing environmental protection through encapsulation.
Solution Approach 2:
The release agent acts as an intermediary between the molding compound and the bond wires, preventing direct contact and adhesion between the compound and wires. This intermediary layer allows the molding compound to provide environmental protection without causing wire instability or disconnection.
4Area of stationary object
If the package size is reduced to meet miniaturization demands, then the device size decreases, but the bond wires become more susceptible to movement and disconnection
Solution Approach 1:
The patent achieves package miniaturization by transitioning from vertical stacking to lateral grid arrangement, which optimizes the use of planar space. This dimensional change allows for reduced package footprint while maintaining adequate bond wire lengths and routing, thereby preserving bond wire stability despite the reduced overall package size.
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 MIM structure securely affixes bond wires, reducing the risk of disconnection and sagging, thereby increasing reliability and allowing for a smaller package size without compromising performance.
Implementation Method 1
an adhesive layer disposed directly over the top surface of the top die
Implementation Method 2
during the encapsulation with mold flow impact, the epoxy-resin does not provide stability for the bond wires
Data Source
AI summary
A semiconductor package includes a multifunctional interface material (MIM) structure provided on a stack of memory dies. The MIM structure includes an adhesive layer disposed directly over a top surface of the top memory die of the stack of memory dies. The MIM structure also includes a polymer layer disposed directly over the adhesive layer. The adhesive layer of the MIM structure receives and secures a portion of the wires of the semiconductor package that contact the top memory die to minimize undesirable movement and disconnection of the wires from the top memory die. The polymer layer of the MIM structure compresses the adhesive layer to aid in securing the wires within the adhesive layer. The polymer layer also protects the adhesive layer within the semiconductor package during operation.