Interposer PCB Assembly for Power Module Co-Planarity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increasing demand for smaller footprint power modules with higher signal output pins and current carrying capacity poses challenges in achieving desired power density, cost-effectiveness, and co-planarity, particularly with the use of surface mount technology parts on printed circuit boards, where interconnect pins prevent low-cost land grid array pads and require tighter pin spacing.
Innovation Solution
The implementation of an interposer printed circuit board assembly with discrete pins and solder bumps that provide thermal and electrical conductivity, allowing for power signal transmission and control signal transmission, and featuring a pad structure with outer and inner solder bumps that adjust height during reflow soldering to match the pin height, enabling tighter spacing and reduced assembly costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If surface mount technology parts are used on the bottom side of the PCB to achieve higher power density, then the number of signal output pins increases, but the footprint area decreases making it difficult to maintain co-planarity and accommodate interconnect pins
Solution Approach 1:
The patent introduces an interposer PCB as an intermediate layer between the power module and the main PCB, adding a dimensional layer to the assembly. This interposer PCB with elevated solder bumps creates a three-dimensional interconnection structure that allows bottom-side mounting of power components while maintaining co-planarity of the final assembly, thus resolving the contradiction between high power density and manufacturing precision.
2Ease of operation
If interconnect pins are used to provide standoff for bottom side surface mount parts, then clearance is provided, but low cost land grid array pads cannot be used and assembly cost increases
Solution Approach 1:
The interposer PCB acts as an intermediary structure that provides the necessary standoff clearance for bottom-side mounted surface mount parts. Instead of using expensive discrete interconnect pins, the interposer PCB with its elevated solder bumps creates the required clearance while enabling the use of cost-effective land grid array pads, thus resolving the contradiction between ease of operation and ease of manufacture.
3Productivity
If all output pins are fitted on the bottom side of the PCB, then power density increases, but pin pitch must be reduced making assembly more difficult
Solution Approach 1:
By transitioning from a two-dimensional pin arrangement to a three-dimensional structure with an interposer PCB and elevated solder bumps, the patent enables higher power density on the bottom side without requiring reduced pin pitch. The vertical dimension provided by the interposer allows closer spacing while maintaining assembly feasibility, resolving the contradiction between productivity and device complexity.
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 enhances power density, reduces assembly costs, and achieves the necessary co-planarity for surface mount technology, allowing for the use of thinner stencils and improved thermal and electrical conduction, while eliminating the need for pre-co-planar solder bumps, thus addressing the challenges of smaller footprint and higher current requirements.
Implementation Method 1
The third height may be equal to the second height after a reflow soldering process alters the outer solder bump
Implementation Method 2
The pin may be a discrete pin with greater thermal and electrical conductivity than a signal path through the interposer circuit board
Implementation Method 3
The pin may be a discrete pin with greater thermal and electrical conductivity than a signal path through the interposer circuit board
Data Source
AI summary
Interposer printed circuit boards for power modules and associated methods are disclosed. In at least one illustrative embodiment, a printed circuit board assembly may comprise a printed circuit board having a surface, an electrical component mounted on the surface, a pin mounted on the surface, and an interposer printed circuit board mounted on the surface. The electrical component may have a first height orthogonal to the surface. The pin may have a second height orthogonal to the surface, where the second height is greater than the first height. The interposer printed circuit board may comprise a pad and an outer solder bump positioned on the pad. The outer solder bump may be positioned at a third height orthogonal to the surface, where the third height is greater than the first height.