Flexible Interposer Semiconductor Package Curved Substrate Stress
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Solution Overview
Problem
Conventional semiconductor packages fail to maintain reliable electrical connections when the substrate is curved, leading to faulty connections due to cracking at the joints between the IC chip and solder balls or semiconductor chip and interposer.
Innovation Solution
A semiconductor package design featuring a bendable and flexible support block at the peripheral edge of the semiconductor part, with an interposer having a flexible resin film wiring pattern electrically connected to the semiconductor part, allowing the interposer to curve and absorb stress, thereby mitigating stress on the semiconductor part and improving connection reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the substrate is made curved to enable lighter, thinner and smaller electronic devices with curved surface design, then the design flexibility and space utilization are improved, but the electrical connections become unreliable due to cracking at the joints between the IC chip and solder balls or semiconductor chip and interposer
Solution Approach 1:
The support block is divided into a first block and a second block that can move relative to each other, allowing the structure to segment and adapt to curved surfaces while maintaining connection integrity. This segmentation enables the support block to follow the curvature of the substrate without causing cracks in the electrical connections.
Solution Approach 2:
The support block is designed with dynamic movement capability between the first and second blocks, allowing it to adjust its configuration in response to substrate curvature. This dynamic structure maintains electrical connection reliability by adapting to the curved surface rather than resisting it with a fixed rigid structure.
2Strength
If a rigid support structure is used to maintain structural integrity, then the mechanical strength is improved, but the structure cannot follow the curvature of the substrate leading to cracking and faulty connections
Solution Approach 1:
The support block is segmented into movable first and second blocks that can shift relative to each other, providing both structural integrity through the overall support structure and curvature following capability through the relative movement of segments.
Solution Approach 2:
The support block transitions from a static rigid structure to a dynamic structure where the first and second blocks can move relative to each other, enabling the structure to maintain strength while adapting to curved substrate surfaces.
3Stability of the object's composition
If the interposer is rigidly fixed to the semiconductor chip, then the connection stability is improved, but the structure cannot absorb stress during curving leading to cracking
Solution Approach 1:
The support block's ability to move between first and second positions allows the interposer assembly to dynamically absorb stress during curving while maintaining connection stability, preventing cracks from forming in the rigidly fixed interposer.
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
The design enables the semiconductor package to maintain reliable connections even when the substrate is curved, eliminating faulty connections by allowing the interposer to flex and absorb stress, thus improving connection reliability.
Implementation Method 1
an interposer bridging the support blocks with the support blocks being situated between the interposer and the semiconductor part, and having a wiring pattern in a flexible resin film
Implementation Method 2
a bendable and flexible support block disposed at least at two locations on a peripheral edge of the semiconductor part on the other face
Data Source
AI summary
Even when a substrate on which a semiconductor package has been mounted is made curved, stress upon electrical connections is mitigated, thereby eliminating faulty connections and improving connection reliability. A semiconductor chip has electrodes on a second face thereof. Support blocks, capable of bending and flexing, are placed at two locations on a peripheral edge of a first face of the semiconductor chip. An interposer is placed so as to span the support blocks with the support blocks interposed between itself and the semiconductor chip, and has a wiring pattern in a flexible resin film. Two end portions of the interposer are folded back onto the side of the second face of the semiconductor chip, and the wiring pattern thereof is electrically connected to the electrodes of the semiconductor chip.