Conductive Spacer Structure for Stacked IC Package Height Reduction
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Solution Overview
Problem
Current stacked integrated circuit package systems face challenges in reducing height, increasing manufacturing yield, and lowering costs due to the use of spacers that require additional manufacturing steps, limit height reduction, and result in non-uniform spacing and assembly defects.
Innovation Solution
A conductive spacer structure with conductive elements surrounded by a spacer filler is used to create a uniform space between integrated circuit devices, allowing for improved bondline thickness control, cost reduction, and enabling the use of known-good-devices (KGD) without assembly, while also serving as test points and potentially aiding in heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional spacers (silicon or interposers) are used for electrical connections in stacked integrated circuits, then electrical connectivity is achieved, but manufacturing costs increase and manufacturing yields decrease due to additional steps and structures
Solution Approach 1:
The patent extracts the spacer function from traditional silicon or interposer materials and implements it through a simplified conductive adhesive assembly process. The conductive adhesive serves multiple functions (spacing, electrical connection, and mechanical bonding) simultaneously, eliminating the need for separate spacer structures and reducing manufacturing steps.
Solution Approach 2:
The conductive adhesive structure performs multiple functions: it provides spacing between dice, establishes electrical connections through conductive paths, and serves as the bonding medium for attaching dice to the substrate. This multi-functionality reduces the number of components and manufacturing steps required.
2Length of moving object
If traditional spacers are used to provide spacing for electrical connections, then electrical connectivity is established, but package height cannot be reduced due to the additional space required
Solution Approach 1:
The patent changes the physical parameters of the spacing structure by using a thin layer of conductive adhesive (controlling thickness parameter) rather than thick spacer materials. The thickness of the conductive adhesive layer can be precisely controlled during application, enabling uniform spacing and reduced package height while maintaining electrical connectivity.
3Length of moving object
If spacer films are used to reduce spacing thickness, then package height is reduced, but rigidity and uniform thickness are insufficient causing tilting or non-uniform spacing
Solution Approach 1:
The patent uses a composite material approach by combining the adhesive matrix with conductive particles or fillers. This composite structure provides both the mechanical properties needed for rigidity and spacing uniformity, and the electrical conductivity needed for signal transmission. The adhesive provides structural support while the conductive phase enables electrical connectivity.
4Reliability
If die are tested individually before assembly, then assembly defects are reduced, but manufacturing cost and complexity increase due to additional testing steps
Solution Approach 1:
The patent implements preliminary testing of individual die before they are assembled into the stacked configuration. This allows defects to be identified and eliminated early in the process, ensuring that only functional die are assembled. The conductive adhesive structure facilitates this by providing accessible test points before final packaging.
Data Source
AI summary
A stacked integrated circuit package system is provided including providing a first device and a second device with the first device, the second device, or a combination thereof having an integrated circuit die; forming a conductive spacer structure over the first device with the conductive spacer structure having a spacer filler around a conductive element; mounting the second device over the conductive spacer structure and the first device; and encapsulating the first device, the second device, and the conductive spacer structure.