Thin Electronic Module Rigid Spacer Flip Chip Mounting
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Solution Overview
Problem
Existing electronic modules for thin microcircuit cards face challenges in efficiently making electrical connections between numerous contact pads due to deformation during assembly and miniaturization, particularly when interconnecting memory components with microcontrollers, as traditional flip chip and wire bonding techniques become impractical with high numbers of connections.
Innovation Solution
The introduction of a rigid intermediate interconnection plate with a silicon substrate and interconnection wiring network, using wire bonding and flip chip techniques, facilitates connections between the flexible support and electronic components, reducing the number of connections needed and allowing for efficient assembly of components with multiple pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional wire bonding technique is used for connecting numerous contact pads, then electrical connections can be made, but the number of connections exceeds ten making the technique impractical and increasing manufacturing complexity
Solution Approach 1:
The patent introduces an intermediate rigid support structure (wafer) between the flexible circuit and the integrated circuit chip. This wafer serves as a mediator that provides a stable platform for wire bonding, allowing numerous electrical connections to be made reliably without the deformations that occur when bonding directly to the flexible circuit. The wafer absorbs the mechanical stress and provides a rigid surface for the wire bonding process, enabling connections to exceed ten pads without increasing manufacturing complexity.
2Productivity
If flip chip technique is used for mounting integrated circuits, then assembly speed improves, but deformations during chip postponement make the technique unusable with high numbers of connection pads
Solution Approach 1:
The rigid wafer acts as an intermediary platform that enables flip chip mounting by providing a stable, deformation-resistant surface during the chip positioning and bonding process. The wafer's rigidity prevents the deformations that would otherwise occur during chip postponement, allowing high-precision alignment of numerous connection pads even when mounting multiple integrated circuits with high numbers of pads.
3Length of stationary object
If module thickness is reduced to fit thin microcircuit cards, then card thinness is achieved, but space constraints limit the available volume for electrical connections and component mounting
Solution Approach 1:
The patent utilizes the third dimension (thickness) effectively by introducing a rigid wafer that extends vertically from the flexible circuit. This allows electrical connections to be made in multiple layers and dimensions, with wires routing through and around the wafer structure. The intermediate wafer creates additional spatial dimensions for wire routing and component placement, enabling numerous connections to be made within the constrained thickness of thin microcircuit cards.
Data Source
Figure 1
Figure 2
AI summary
This thin electronic module (3) includes a rigid interconnecting spacer (7) positioned between its flexible substrate (6) and one or more electronic components (9) with numerous connection pins. The presence of this rigid interconnecting spacer (7) allows for a "flip chip" mounting of the module's electronic components (9) without significantly increasing the module's thickness, offering excellent efficiency far superior to that obtained by mounting the electronic components directly onto the spacer (6). Consequently, it contributes to a significant reduction in the manufacturing cost of electronic modules containing one or more integrated circuits with numerous connection pins.