TSV Interconnection Structure for Wafer-PCB Warpage Reduction
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Solution Overview
Problem
The integration of System on Wafer (SOW) technology faces challenges due to the mechanical strength limitations of wafers and RDL wiring, making it difficult to achieve large-size SOW with stable and reliable operation, as peripheral circuits like power management and mechanical transmission modules require integration on traditional PCBs, which have better mechanical strength and wiring capabilities.
Innovation Solution
An interconnection structure using a TSV process is developed, featuring a rigid structural part to fix warped PCBs, viscous glue for fixation, and elastic connectors to connect wafer pressure welding pads with chiplets, along with a liquid cooling channel for heat dissipation, enabling stable interaction between large-sized wafers and PCBs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If SOW technology is used to integrate functional circuits on a wafer, then computing performance and integration density are improved, but mechanical strength and structural stability deteriorate due to wafer limitations
Solution Approach 1:
The system is divided into two separate substrates: a first substrate (wafer) for integrating functional circuits and a second substrate (PCB) for mechanical support and peripheral circuits. This segmentation allows each substrate to specialize in its strength while maintaining integration benefits.
Solution Approach 2:
The first substrate (SOW) is mounted within a groove on the second substrate (PCB), creating a nested structure where the wafer is housed and supported by the more mechanically robust PCB, combining the high integration density of SOW with the mechanical strength of PCB.
2Stability of the object's composition
If peripheral circuits are integrated on traditional PCB to ensure mechanical strength, then structural stability is improved, but integration density and computing performance deteriorate
Solution Approach 1:
The system separates functional circuit integration (on wafer) from mechanical support and peripheral circuits (on PCB), allowing each substrate to optimize for its designated function without compromise.
Solution Approach 2:
The second substrate (PCB) serves multiple functions: providing mechanical support, hosting peripheral circuits (power management, I/O interfaces, sensors), and structurally stabilizing the first substrate through the groove mounting structure.
3Reliability
If TSV holes are drilled through the wafer for electrical connection, then interconnection bandwidth is improved, but manufacturing complexity and precision requirements worsen
Solution Approach 1:
Elastic connectors serve as intermediaries between the TSV holes on the wafer and the PCB pads, providing mechanical compliance and stress relief that reduces the precision requirements for both TSV alignment and PCB mounting while maintaining reliable electrical connections.
4Ease of operation
If elastic connectors are used to connect wafer TSV holes with PCB pads, then mechanical compliance is improved, but connection reliability worsens due to potential contact instability
Solution Approach 1:
The elastic connectors change their physical parameters (compression distance, contact pressure) dynamically to accommodate thermal expansion and mechanical stress, maintaining stable electrical contact across varying operating conditions while providing necessary mechanical compliance.
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
This solution significantly reduces PCB warpage by at least 90%, facilitates high-density and high-speed signal connection, and improves electrical connections between wafers and PCBs, addressing the limitations of traditional SOW integration and heat dissipation.
Implementation Method 1
a lower surface of the system on wafer is connected with the bottom groove by a viscous glue
Implementation Method 2
a liquid cooling channel for heat dissipation
Implementation Method 3
liquid cooling channel for heat dissipation
Implementation Method 4
elastic connectors to connect wafer pressure welding pads with chiplets
Data Source
AI summary
An interconnection structure of a system on wafer and a PCB based on a TSV process and a method for manufacturing the same. The structure comprises a bottom structural part and a top structural part, the upper surface of the bottom structural part is provided with a plurality of positioning holes; the lower surface of the top structural part is provided with positioning pins; the upper surface of the bottom structural part is provided with a bottom groove, and a system on wafer is arranged in the bottom groove; the lower surface of the system on wafer is connected with the bottom groove; the lower surface of the top structural part is provided with a top groove, and a PCB preformed die is connected in the top groove, and the other end of the PCB preformed die is connected with the system on wafer by an elastic connector.