Molded Via Structures for Reliable PCB Interconnects

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Solution Overview

Problem

Existing methods for forming conductive structures on printed circuits often result in unreliable electrical connections and poorly defined shapes and locations of metal traces, leading to suboptimal integration with other device structures.

Innovation Solution

The formation of vias in printed circuits during plastic molding allows for the connection of surface metal traces to underlying metal traces, using mold pins or drilling, and filling these vias with conductive materials like solder or adhesive to create reliable conductive pathways for structures such as antennas, shielding, and electrodes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional methods are used to form conductive structures on printed circuits, then the manufacturing process is simple, but the electrical connections are unreliable and the shapes and locations of metal traces are poorly defined

Engineering Contradiction:

Improvedefinition of shapes and locations of metal tracesVSAvoidcomplexity of molding and via formation process

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by forming vias during the plastic molding process itself, rather than as a separate subsequent step. The mold pins are positioned to create via holes at precise locations before the plastic is injected, ensuring accurate definition of via shapes and locations while integrating the operation into the existing molding workflow

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses an intermediary approach by employing mold pins as temporary structures that define via locations during molding. These pins serve as mediators between the molding process and the final via structures, enabling precise via formation through the plastic material while the pins themselves are removed after molding

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If care is not taken in forming conductive structures, then the manufacturing process is fast, but the electrical connections will not be reliable

Engineering Contradiction:

Improvereliability of electrical connectionsVSAvoidspeed of conductive structure formation

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent merges the via formation operation with the plastic molding process into a single integrated operation. By combining these two steps that were traditionally performed separately, the method achieves reliable electrical connections through precise via placement while maintaining high productivity by eliminating the need for a separate via formation step

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The molding process itself serves to create the vias through the plastic material. The mold pins automatically define via locations and shapes during the normal molding operation, making the via formation a self-service function of the molding process rather than requiring additional dedicated equipment or operations

Inventive Principle:

Principle #25Self-service

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 ensures reliable electrical connections and defined conductive structures, enhancing the integration and functionality of electronic devices by providing robust and well-defined conductive pathways within molded plastic enclosures.

Implementation Method 1

covering the metal traces on the printed circuit with mold pins in a molding tool during plastic molding operations

Methodology Applied

Scientific EffectPhysical containment: Physical Containment

Implementation Method 2

Vias may also be filled with conductive material such as solder or conductive adhesive

Methodology Applied

Scientific EffectSoldering: Soldering

Implementation Method 3

Vias may also be filled with conductive material such as solder or conductive adhesive

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 4

Plated metal traces or other metal traces may extend along the interior surfaces of via holes

Methodology Applied

Scientific EffectMetal deposition: Deposition (physical)

Data Source

PatentUS9582085B2Electronic devices with molded insulator and via structures

Publication Date: 2017.02.28 APPLE INC

AI summary

An electronic device may have printed circuits to which electrical components are mounted. Plastic may be molded over a printed circuit. Vias may be formed in the printed circuit that connect metal traces on the surface of the molded plastic to metal traces on the printed circuit. The vias may be formed by drilling or by covering the metal traces on the printed circuit with mold pins in a molding tool during plastic molding operations. Plated metal traces or other metal traces may extend onto the interior surface of via holes. Vias may also be filled with conductive material such as solder or conductive adhesive. Metal members that are soldered or otherwise connected to printed circuit traces may be used in coupling surface metal traces to printed circuit traces. Antenna structure, shielding structures, and electrodes for a stylus may be formed using the metal traces on the molded plastic.