BGA Support Structure to Prevent Solder Bridging During Reflow
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Solution Overview
Problem
The challenge of short circuits between neighboring interconnection elements in electronic packages, particularly in Ball Grid Array (BGA) devices, due to warpage during soldering processes, which can be exacerbated by the mismatch of thermal expansion coefficients and high compression forces.
Innovation Solution
A support structure with non-collapsible support elements is integrated into the BGA device, made from materials that withstand solder melt temperatures, maintaining a predefined spacing and preventing collapse during soldering, ensuring stable mechanical support and electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If solder connection elements are arranged in a two-dimensional array with small distances between neighboring elements, then the area utilization of the package bottom surface is improved, but the risk of electric bridging and short circuits between neighboring balls increases
Solution Approach 1:
A support structure comprising support elements is introduced as an intermediary component between the substrate and the component carrier. This support structure maintains a predefined spacing between the substrate and component carrier, preventing excessive compression of solder connection elements that would cause them to bridge and create short circuits, while allowing the dense two-dimensional array arrangement to be maintained for optimal area utilization.
2Ease of manufacture
If the package is heated above solder reflow temperature during assembly, then the soldering process is enabled, but unwanted warpage of the package occurs due to thermal expansion mismatch
Solution Approach 1:
The support elements are designed with specific material properties and geometric configurations (such as dome-shaped or cushion-like structures) that allow them to withstand high temperatures during reflow soldering without deforming. These parameter changes in material selection and structural design enable the support structure to maintain its shape and function throughout the thermal processing cycle, preventing package warpage while enabling proper soldering.
3Stability of the object's composition
If support structure is added to prevent solder connection element collapse, then the mechanical stability during soldering is improved, but the device complexity increases
Solution Approach 1:
The support structure is designed to perform multiple functions simultaneously: it provides mechanical support to prevent solder ball compression, maintains the predefined spacing between substrate and component carrier, and can also serve as a template for solder ball placement. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving the desired mechanical stability.
4Strength
If heavy elements such as heat sinks are attached to the package with additional pressure, then the thermal contact is improved, but the compression on solder connection elements increases causing short circuits
Solution Approach 1:
The support structure is installed beforehand to provide preliminary counter-action against compression forces. When heavy elements like heat sinks are attached with additional pressure, the support elements absorb and distribute these compression forces, preventing them from being transmitted to the solder connection elements. This preliminary protective measure ensures that both good thermal contact and solder connection integrity are maintained.
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
Prevents unwanted short circuits and maintains reliable electrical connections by maintaining spacing and structural integrity during soldering processes, even under high compression forces, enhancing process reliability and signal integrity.
Implementation Method 1
The support structure is non-collapsible during expected use and processes, resists warpage, or is rigid with respect to compressive forces
Implementation Method 2
unwanted warpage of the package in particular within a reflow oven, wherein an assembly comprising the package and a component carrier is heated up above a certain solder reflow temperature
Data Source
AI summary
It is described a interconnect array device (e.g., Ball Grid Array (BGA) device) comprising (a) a substrate having a substrate body and a main surface; (b) an array of solder connection elements formed at the main surface; and (c) a support structure formed at the main surface. The support structure is configured for maintaining, during a soldering process, a predefined spacing between the main surface of the substrate and a further main surface of a component carrier onto which the Ball Grid Array is mounted. The support structure comprises at least one support element. Further described is an electronic package with such a Ball Grid Array device and a method for manufacturing an electronic assembly comprising such an electronic package mounted on a component carrier.