Wiring Board Warping Control via Temporary Bonding

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Solution Overview

Problem

Existing wiring board manufacturing methods face challenges with warping due to thermal expansion coefficient differences between materials, which restrict design flexibility and increase production complexity and costs, while prior solutions complicate the process and reduce reliability.

Innovation Solution

A method involving a symmetrical double-sided wiring board structure with structural aids and a planar temporary bonding means, allowing for embedding electrical components in slots with matching thermal expansion coefficients, enabling simple fabrication and robustness without design restrictions, using materials like molding resin sheets and polymer composites.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If additional layers are added to manipulate thermal expansion characteristics, then warping is reduced, but device complexity increases

Engineering Contradiction:
Improvewarping reductionVSAvoidstructure complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

A temporary bonding means is introduced as an intermediary layer between the wiring board structure and the external environment during manufacturing. This temporary layer compensates for thermal expansion differences without requiring permanent structural modifications, thus reducing warping while maintaining structural simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The thermal expansion characteristics are managed by changing the parameters of the temporary bonding means (such as its thickness, material properties, or bonding strength) rather than modifying the fundamental wiring board structure. This allows warping control through parameter adjustment without increasing device complexity.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If thermal treatment is applied to reduce warping, then stability improves, but manufacturing time increases

Engineering Contradiction:
Improvewarping controlVSAvoidmanufacturing time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The temporary bonding means is applied in advance during the manufacturing process to prevent warping from occurring in the first place, rather than requiring subsequent thermal treatment to correct warping. This preliminary action eliminates the need for time-consuming thermal processing steps.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The warping control function is extracted from the thermal treatment process and transferred to the temporary bonding means. This separates the warping prevention function from time-consuming thermal processing, allowing manufacturing to proceed more efficiently.

Inventive Principle:
Principle #2Taking out (Extraction)

3Productivity

If components are densely mounted to reduce size, then productivity increases, but manufacturing precision requirements increase

Engineering Contradiction:
Improvepackaging densityVSAvoidalignment precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The temporary bonding means provides preliminary support and positioning for densely mounted components, preventing misalignment before it occurs. This preliminary anti-action maintains manufacturing precision even at high packaging densities by compensating for thermal and mechanical stresses.

Inventive Principle:
Principle #9Preliminary anti-action

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 approach minimizes warping, enhances mechanical and electrical robustness, maintains design flexibility, and simplifies the manufacturing process, while maintaining cost-effectiveness and reliability, allowing for efficient production with existing equipment modifications.

Implementation Method 1

The warping may be caused e.g. during thermal treatment of the wiring board by differences between thermal expansion coefficients of layers of different materials in the wiring board structure

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP2274962B1Wiring board and method for manufacturing the same
Publication Date: 2018.07.11 GE EMBEDDED ELECTRONICS OY
  • EP2274962B1 patent drawingFigure 1~3
  • EP2274962B1 patent drawingFigure 4~6
  • EP2274962B1 patent drawingFigure 7~9

AI summary

A method for manufacturing a wiring board, comprising the steps of mounting at least one structural aid (10) on each side of a planar temporary bonding means (2), arranging a slot (3) from the at least one structural aid (10) on each side of the planar temporary bonding means (2), embedding the electrical component (4) in the slot (3), such that the terminals (6) of the electrical component (4) face away from the planar temporary bonding means (2), mounting at least one electrical component (4) on a component foil (5), such that the terminals (6) of the electrical component (4) face the component foil (5), mounting the component foil (5) at least partially on the at least one structural aid (10), on each side of the planar temporary bonding means (2).