Thin Printed Circuit Board Carrier for Adhesive-Free Packaging
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Solution Overview
Problem
The challenge of handling and processing thin printed circuit boards with a thickness of 80 μm or less is exacerbated by their brittleness and the lack of suitable facilities for conventional semiconductor packaging, leading to issues such as damage and warpage during manufacturing.
Innovation Solution
A printed circuit board design incorporating a carrier with complementary surface roughness on a metal foil portion and solder resist, allowing for adhesive-free attachment and stable packaging of semiconductor chips, even with thin boards, using a method that includes forming a printed circuit board layer, applying solder resist, attaching a carrier with a roughness surface, mounting a semiconductor chip, and separating the board without adhesives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the board is made thin to reduce overall package thickness, then the thickness is reduced, but the board becomes easily broken during processing due to high brittleness
Solution Approach 1:
A carrier is attached to the thin printed circuit board before any processing steps are performed. This preliminary attachment provides mechanical support and protection to the fragile thin board throughout the entire manufacturing process, preventing breakage while allowing the board to maintain its reduced thickness of 80 μm or less.
Solution Approach 2:
The carrier serves as an intermediary object that mediates between the thin printed circuit board and the manufacturing process. By attaching the board to the carrier, the carrier absorbs mechanical stresses and handling forces, protecting the thin board from breakage during lamination, drilling, and other processing steps.
2Length of stationary object
If a thin board with thickness of 80 μm or less is used, then the overall package thickness is reduced, but conventional semiconductor packaging facilities are unsuitable for handling such thin boards
Solution Approach 1:
The thin printed circuit board is attached to a carrier before entering the semiconductor packaging process. This preliminary preparation enables conventional packaging facilities to handle the thin board as if it were a thicker, more rigid substrate, making the manufacturing process compatible with existing equipment while maintaining the benefits of thin board design.
3Stability of the object's composition
If adhesive is used to attach the board to the carrier, then the board can be fixed, but additional manufacturing steps and materials are required
Solution Approach 1:
The carrier and thin printed circuit board are designed to attach to each other through their own inherent properties - specifically, through surface roughness characteristics that create mechanical interlocking. This self-attachment mechanism eliminates the need for separate adhesive materials and additional bonding process steps, reducing manufacturing complexity while ensuring stable fixation.
Solution Approach 2:
The surface roughness parameters of the carrier and board are specifically designed and controlled to enable direct attachment. By optimizing the roughness parameters, the surfaces create sufficient mechanical interlocking and friction to hold the thin board securely without requiring adhesives, simplifying the manufacturing process.
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 enables the stable packaging of semiconductor chips using thin printed circuit boards, preventing damage and warpage during transfer and separation from the carrier, while maintaining adhesion and stability.
Implementation Method 1
A surface of the metal foil portion and a surface of the solder resist that are in contact with each other may have surface roughness complementary with each other
Data Source
AI summary
A printed circuit board includes: a plurality of insulating layers; a plurality of wiring pattern layers disposed on at least one surface of the plurality of insulating layers; a via connecting wiring pattern layers, among the plurality of wiring pattern layers, disposed on upper and lower surfaces of one of the plurality of insulating layers to each other; a connection pad disposed on a surface of an outermost layer among the plurality of insulating layers; and a solder resist having a hole exposing at least a portion of the connection pad. An external surface of the solder resist has surface roughness.