Folded Flexible Circuit 3D Packaging for Simpler Die Stacking
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Solution Overview
Problem
Existing 3D package configurations face challenges such as complexity, time-wasting processes, low yield rates, and high costs due to thin film deposition, photolithography, and etching, which are not efficiently addressed by conventional techniques.
Innovation Solution
A novel 3D package configuration utilizing a folded flexible circuit board structure vertically stacked on a package substrate, comprising semiconductor dies bonded to die bonding zones on flexible circuit boards, allowing for alternative stacking and electrical connections through conductive holes, using materials like copper and insulating substrates like Polyimide (PI) for efficient manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional 3D package configurations use thin film deposition, photolithography, and etching processes, then interconnection and integration are achieved, but the manufacturing process becomes complicated and time-consuming
Solution Approach 1:
The patent extracts and removes the complex thin film deposition, photolithography, and etching processes from the 3D package manufacturing flow. Instead, it uses direct bonding of semiconductor wafers to flexible circuit boards with pre-formed conductive patterns, eliminating multiple complex processing steps while maintaining electrical interconnection reliability
Solution Approach 2:
The patent replaces the mechanical and chemical processes (thin film deposition, photolithography, etching) with a simpler mechanical bonding approach. Semiconductor wafers are directly bonded to flexible circuit boards using conventional bonding techniques, substituting complex multi-step processes with a more straightforward mechanical assembly method
2Reliability
If conventional 3D package configurations use multiple semiconductor processing steps, then electrical interconnection is achieved, but yield rate decreases and cost increases
Solution Approach 1:
The patent performs preliminary actions by pre-forming conductive patterns on flexible circuit boards before semiconductor wafer bonding. The flexible circuit boards are prepared in advance with complete electrical interconnection paths, allowing semiconductor wafers to be directly bonded without requiring subsequent complex processing steps, thereby improving yield rate and reducing costs
Data Source
AI summary
A novel 3D package configuration is provided by stacking a folded flexible circuit board structure on a package substrate and electrically connected therewith based on the foldable characteristics of the flexible circuit board, and the high temperature resistance of the flexible circuit board which is suitable for insulating layer process, metal layer process, photolithography process, etching and development process, to make conventional semiconductor dies of various functions be bonded on one die and/or two side of a flexible circuit board and electrically connected therewith in advance.