Board-Level Substrate Support Layout for Solder Warpage Control
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Solution Overview
Problem
The increasing size of chip packages due to higher chip channels and computing power leads to warping and deformation issues in package substrates and printed circuit boards, causing soldering problems like solder bridging and open soldering, which complicates batch soldering yields.
Innovation Solution
A board-level structure with upper and lower-layer substrates and support members, featuring gap regions with varying vertical distances and support members distributed at intervals to maintain specific intervals, minimizing solder bridging defects by supporting the substrates during temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the chip package size is increased to provide higher computing power and more chip channels, then the processing capability is improved, but the warping and deformation of package substrate and printed circuit board become more severe
Solution Approach 1:
The gap region is divided into multiple sub-regions (first gap sub-region, second gap sub-region, third gap sub-region) with different vertical distance characteristics. This segmentation allows differential support strategies to be applied to different areas, addressing the deformation problem while maintaining the large package size needed for high computing power
Solution Approach 2:
Different regions of the gap are assigned different support characteristics based on their vertical distance properties. The first gap sub-region (with smaller vertical distance) receives support members at different positions than the second and third gap sub-regions. This local differentiation ensures that each region gets the appropriate level of support needed, preventing soldering defects caused by substrate warping while maintaining overall package integrity
2Reliability
If the package substrate and printed circuit board are soldered together, then electrical interconnection is achieved, but soldering defects such as solder bridging and open soldering occur due to large deformation
Solution Approach 1:
Support members are pre-positioned in the gap region before the soldering process. These support members maintain the proper vertical distance between the package substrate and printed circuit board during heating and soldering, preventing solder bridging and open soldering defects that would otherwise occur due to thermal deformation. This preliminary support action ensures soldering quality is maintained even with large package sizes
Solution Approach 2:
Support members act as intermediary elements between the package substrate and printed circuit board. They maintain the necessary gap distance during the soldering process, mediating the thermal expansion and contraction forces that would otherwise cause soldering defects. The support members enable reliable electrical interconnection by ensuring proper alignment and spacing throughout the soldering operation
3Manufacturing precision
If support members are added to maintain interval between substrates, then soldering quality is improved, but device complexity increases
Solution Approach 1:
Support members are strategically placed only in specific sub-regions of the gap where vertical distance requirements are most critical. The first gap sub-region receives support members at different positions than the second and third gap sub-regions. This localized approach improves soldering quality where needed without adding unnecessary complexity to the entire structure
Solution Approach 2:
Rather than providing uniform support across the entire gap region, support members are placed in a partial manner - specifically in the first gap sub-region and selectively in the second and third gap sub-regions. This partial action provides sufficient support to prevent soldering defects while minimizing the number of support members needed, thus reducing overall structural complexity
Data Source
AI summary
The technology of this application relates to a board-level structure that includes an upper-layer substrate, a lower-layer substrate, and a plurality of support members that are supported between the upper-layer substrate and the lower-layer substrate. In an example embodiment, a gap exists between the upper-layer substrate and the lower-layer substrate, the gap includes at least one first gap region and at least one second gap region, the first gap region and the second gap region are spaced, a spaced region between the first gap region and the second gap region does not include the first gap region or the second gap region, and a maximum vertical distance between the upper-layer substrate and the lower-layer substrate in the first gap region is less than a minimum vertical distance between the upper-layer substrate and the lower-layer substrate in the second gap region.