Flexible Die Embedding with Patterned Adhesion
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Solution Overview
Problem
Traditional chip packaging technologies are two-dimensional, limiting miniaturization and requiring precise placement and high-density interconnections, which can lead to chip breakage and alignment challenges during pressure application, especially for thin chips with fine pitches.
Innovation Solution
A method involving attaching non-bumped dies to a flexible substrate with a patterned adhesion promoter, allowing for embedding and testing before embedding, using a flexible and electrically isolating polyimide layer with a fan-out metallization to reduce pressure on chips and enable relaxed pitch connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If traditional two-dimensional chip packaging is used, then routing space is available, but signal path length is minimized and miniaturization is limited
Solution Approach 1:
The patent transitions from two-dimensional planar packaging to three-dimensional embedding, where chips are vertically embedded within the substrate rather than placed on the surface. This dimensional change allows signal paths to be routed through multiple layers and via holes, significantly reducing signal path length while enabling higher density interconnections and improved miniaturization.
2Ease of manufacture
If precise placement and high-density interconnections are used, then routing capability is improved, but chip breakage and alignment challenges increase
Solution Approach 1:
The patent applies adhesion promoters to the substrate before embedding the chips, creating pre-formed adhesive regions that guide chip placement. This preliminary action ensures proper alignment and secure bonding without requiring excessive placement precision or applying high pressure during assembly, thereby reducing chip breakage risk while maintaining routing capability.
3Strength
If pressure is applied during placement, then chip bonding is achieved, but thin chips with fine pitches are more likely to break
Solution Approach 1:
The patent introduces adhesion promoters as intermediary substances between the substrate and chips. These promoters create chemically active bonding surfaces that achieve strong adhesion through chemical bonding rather than mechanical pressure, allowing thin chips with fine pitches to be bonded securely without applying damaging forces during the placement process.
4Manufacturing precision
If alignment precision is increased, then connection accuracy is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies adhesion promoters locally at specific embedding positions on the substrate rather than uniformly across the entire surface. This creates localized adhesive regions that guide chip placement with high precision while keeping the rest of the substrate simple, thereby achieving accurate alignment without increasing overall manufacturing process complexity.
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 creation of ultra-thin, flexible chip packages that are bendable and reduce the risk of chip breakage, allowing for more relaxed alignment constraints and efficient embedding in 3D stacks, while facilitating the testing of chips before embedding.
Implementation Method 1
a) providing a flexible substrate with a patterned adhesion promoter
Data Source
Figure 1(a)~1(d)
Figure 2A~2F
Figure 3
AI summary
Manufacturing a semiconductor device involves forming (701, 801, 802,803,804) a first flexible film (11) on a rigid carrier substrate (1), attaching (703, 704, 705, 805, 806, 807, 808) a die (3) to the flexible film, so as to leave contacts (6) on the die exposed, forming (706, 809) a wiring layer (4) to contact the contacts of the die, and releasing (706, 809) the flexible film where the die is attached, from the carrier. An area of the first flexible film where the die is attached can have a lower adhesion to the rigid carrier substrate than other areas. Then the releasing can involve cutting the first flexible film to release a part of the area of lower adhesion, and leave an area of higher adhesion. A combined thickness of the die, the first flexible film and the wiring layer can be less than 150µm, so the device is bendable. Devices can be stacked.