Symmetrical Solder Pad Layout for Stable PCB Module Assembly

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Solution Overview

Problem

Existing electrical modules with embedded semiconductor components experience tilting during soldering, leading to inconsistent air gaps, flux residue issues, and reduced thermal and electrical connections, which complicates washing and underfill processes.

Innovation Solution

The electrical module design features axially symmetrical solder pads arranged on opposite side edges or centered with identical dimensions to minimize tilting, ensuring consistent gap heights for effective washing and underfill processes, and facilitates easy thermal connection to a heat sink.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If prepackage modules are arranged on a carrier board via soldering process, then electrical connections are established, but tilting of the prepackage modules occurs during soldering

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidmodule positioning stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies asymmetry by intentionally designing the solder pad arrangement to be asymmetric relative to the module's geometric center. Specifically, the solder pads are positioned closer to one edge of the module than the other, creating an asymmetric weight distribution during soldering that counteracts the natural tilting tendency. This asymmetric placement compensates for the tilting effect by shifting the center of gravity, thereby maintaining stable module positioning on the carrier board during the soldering process.

Inventive Principle:

Principle #4Asymmetry

2Stability of the object's composition

If tilting is prevented by symmetric solder pad arrangement, then module stability improves, but air gap consistency becomes more difficult to control

Engineering Contradiction:

Improvemodule positioning stabilityVSAvoidair gap height consistency

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent applies local quality by creating different air gap heights at different locations of the module. Specifically, the air gap is designed to be smaller in regions where tilting would occur and larger in other regions. This non-uniform air gap distribution compensates for the tilting effect, ensuring that the module maintains stable contact with the carrier board at critical soldering points while allowing sufficient gap elsewhere for proper underfill and washing processes.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If air gap height is increased to accommodate tilting, then washing and underfill processes become easier, but thermal connection to heat sink deteriorates

Engineering Contradiction:

Improvewashing and underfill process easeVSAvoidthermal connection quality

Core Design Contradiction:

Ease of manufactureVSTemperature

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

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 design stabilizes the electrical module on the circuit board, optimizing washing and underfill processes, enhancing thermal conductivity, and maintaining consistent electrical connections without shadowing effects.

Implementation Method 1

at least three electrical solder pads (6-8) formed on the upper side (21), which are configured to make electrical contact with the electrical component (24) and configured to come into contact with an associated electrical solder pad (41-43) of a circuit board (1) via a solder layer (16-18)

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

the ceramic circuit carrier, together with the semiconductor component and a sheath, for example, made of encapsulating material, forms an electrical module that may be connected to the carrier board or circuit board via contacts formed on its surface

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS12538425B2Electrical module and printed circuit board assembly comprising an electrical module

Publication Date: 2026.01.27 ROLLS ROYCE DEUT LTD & CO KG

AI summary

An electrical module and a circuit board arrangement including an electrical module are disclosed. The electrical module includes an upper side and an underside, the upper side having four rectangularly arranged side edges, an electrical component embedded in the electrical module, and at least three electrical solder pads formed on the upper side configured to make electrical contact with the electrical component and configured to come into contact with an associated electrical solder pad of a circuit board via a solder layer. The solder pads of the electrical module are arranged in a symmetrical arrangement on the upper side of the electrical module, and/or the solder pads are arranged axially symmetrically on the upper side of the electrical module, and/or the solder pads extend along two opposite side edges on the upper side of the electrical module.