XPU Socket Compression Layout for Warpage-Free PCB Pin Loading
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Solution Overview
Problem
The uneven distribution of compressive load on pins in printed circuit boards (PCBs) due to lateral placement of tensile elements creates force moments, leading to warpage and underloading at the center, which affects the reliability of communication between the PCB and installed devices.
Innovation Solution
A peripheral arrangement of pins around an aperture in the PCB, with a processor package pressed against these pins by a compressive force couple, and a separate force couple compressing a heat sink against the processor die, independent of the first force couple, to ensure even load distribution and avoid warpage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If tensile elements are placed laterally spaced away from the contact area to avoid passing through operative parts, then the device complexity is reduced and ease of manufacture is improved, but uneven load distribution occurs creating force moments that lead to warpage and underloading at the center
Solution Approach 1:
The compression force is segmented into two independent force couples: the first force couple compresses the processor package against the socket, and the second force couple compresses the heat sink against the processor die. This segmentation allows each force couple to be optimized independently, with the second force couple applied through aligned apertures to ensure even load distribution at the center while the first force couple handles the peripheral pin loading.
Solution Approach 2:
Aligned apertures through the socket, lid, and bolster plate serve as intermediaries to transmit the second force couple directly to the processor die. This intermediary structure enables the heat sink compression force to be applied concentrically through the center of the device, creating even load distribution without requiring tensile elements to pass through operative parts.
2Reliability
If a peripheral arrangement of pins around an aperture is used, then the pins are evenly loaded and warpage is reduced, but the device complexity increases due to the aperture and peripheral pin configuration
Solution Approach 1:
The aperture serves multiple functions: it defines the peripheral pin arrangement for even load distribution, provides a pathway for the second force couple to compress the heat sink against the die, and allows alignment of the lid and bolster plate. This multi-functionality reduces the need for separate structures, thereby managing device complexity while achieving reliable even loading.
Solution Approach 2:
The pin arrangement is asymmetrically configured in a peripheral pattern around the aperture rather than a uniform grid, which strategically positions pins to capture compressive forces from both force couples and ensures even load distribution across all pins while maintaining structural integrity.
3Device complexity
If a single force couple is used to compress both the processor package and heat sink, then the device complexity is reduced, but the load distribution becomes uneven causing warpage and underloading
Solution Approach 1:
The compression system is segmented into two independent force couples with distinct functions: the first force couple (lid and bolster plate) compresses the processor package against the socket pins, while the second force couple (heat sink and base plate through aligned apertures) compresses the processor die. This segmentation enables independent optimization of each compression zone, ensuring even load distribution at the center through the second force couple while maintaining overall structural simplicity.
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 arrangement ensures even loading of pins, reducing warpage and improving communication reliability between the PCB and the processor package by distributing loads evenly across the pins, thereby enhancing the contact area and stability.
Implementation Method 1
The processor package is pressed against the array of pins by a compressive force couple
Implementation Method 2
a separate force couple compressing a heat sink against a portion of the processor package that is independent of the first force couple
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
An assembly includes a printed circuit board 130 ("PCB"). An aperture extends through the PCB. The assembly also includes a socket 120 that includes the array of pins 124 and a socket board 122 from which the array of pins extends, and a processor package 110. The array of pins extends around a perimeter of the aperture, and the processor package extends over the aperture. The processor package is pressed against the array of pins by a compressive force couple F2, F3.