PCB Anti-Warpage Frame Structure for Memory Package Assembly
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Solution Overview
Problem
Semiconductor systems experience warpage due to mismatched coefficients of thermal expansion between semiconductor devices and printed circuit boards during assembly, leading to issues like cracks and reduced reliability.
Innovation Solution
Incorporating a rigid frame structure around semiconductor packages on the PCB to stabilize the system, using materials like copper or aluminum that resist warping during assembly and operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If semiconductor devices are mounted on PCBs during assembly, then circuit density and functionality are improved, but warpage occurs due to mismatched coefficients of thermal expansion
Solution Approach 1:
A frame structure serves as an intermediary element between the semiconductor devices and the PCB. This frame is specifically designed with thermal expansion properties that mediate the mismatch between the semiconductor devices (with lower CTE) and the PCB (with higher CTE), thereby reducing warpage while maintaining the benefits of high circuit density
Solution Approach 2:
The frame structure changes the thermal expansion parameters of the overall system. By introducing a frame with specific coefficient of thermal expansion properties, the system's response to temperature changes during assembly and operation is modified, reducing the differential expansion that causes warpage
2Ease of manufacture
If heating and cooling processes are applied during assembly, then soldering and bonding are improved, but warpage and cracking increase due to thermal stress
Solution Approach 1:
The frame structure provides beforehand cushioning against thermal stress during heating and cooling processes. It absorbs and distributes the thermal stresses generated during soldering and bonding operations, preventing these stresses from concentrating in critical areas and causing cracks, thereby protecting the reliability of the assembled device
3Strength
If rigid materials are used for semiconductor packages, then mechanical strength is improved, but thermal expansion mismatch with PCB worsens
Solution Approach 1:
The frame structure acts as a composite material solution, combining materials with different thermal expansion properties to create an intermediate structure. This composite approach maintains the mechanical strength benefits of rigid materials while compensating for the thermal expansion mismatch between the semiconductor package and the PCB
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
Reduces warpage by up to 20%, minimizes solder and die cracks, enhances reliability, and increases the lifespan of semiconductor systems.
Implementation Method 1
mismatched coefficients of thermal expansion between semiconductor devices and printed circuit boards during assembly
Data Source
AI summary
Semiconductor systems having anti-warpage frames (and associated systems, devices, and methods) are described herein. In one embodiment, a semiconductor system includes (a) a printed circuit board (PCB) having a first side and a second side opposite the first side, and (b) at least one memory device attached to the PCB at the first side of the PCB. The semiconductor system further includes a frame structure attached to the PCB at the first side of the PCB and proximate the at least one memory device. The frame structure can be configured to resist warpage of the PCB, for example, when the semiconductor system is heated to attach the at least one memory device to the PCB.