Redistribution Layer Attachment for Microfeature Workpieces
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Solution Overview
Problem
Conventional redistribution layer (RDL) formation techniques for microfeature workpieces are costly and inefficient, especially for dies with image sensors, as they require special tooling and techniques to align features on the back side of the die without interfering with the sensors, limiting compatibility with various die types.
Innovation Solution
A separate microfeature workpiece with a redistribution layer is formed and attached to a microfeature workpiece with operable devices, allowing for flexible process selection and avoiding the need for special tooling, by forming the RDL on a substrate without integrated microfeature devices, which can be processed independently and then attached, enabling cost-effective and efficient signal rerouting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional RDL formation techniques are used directly on the die, then alignment with bond pads can be achieved, but the process becomes costly and complex due to special tooling requirements for back-side alignment
Solution Approach 1:
The invention divides the RDL formation process into two independent stages: (1) forming the RDL on a separate carrier substrate, and (2) attaching the carrier with the formed RDL to the die. This segmentation allows each stage to be optimized independently, eliminating the need for complex back-side alignment tooling while maintaining precise alignment through the attachment process.
Solution Approach 2:
The invention introduces a carrier substrate as an intermediary element between the die and the final RDL structure. The carrier serves as a platform for forming the RDL using standard front-side lithography processes, then the entire carrier-RDL assembly is attached to the die, simplifying the overall process while achieving the required alignment.
2Manufacturing precision
If special tooling and techniques are used for back-side RDL formation, then alignment can be achieved, but manufacturing cost increases
Solution Approach 1:
By segmenting the RDL formation from the die and performing it on a separate carrier substrate, the invention enables the use of standard, cost-effective front-side lithography tooling instead of expensive special-purpose back-side alignment equipment.
Solution Approach 2:
The invention creates a copy of the bond pad pattern on the carrier substrate through standard lithography processes, allowing the RDL to be formed using conventional, cost-effective manufacturing techniques rather than requiring specialized back-side processing equipment.
3Ease of manufacture
If RDL formation is performed on the front side of the die, then standard lithography processes can be used, but image sensor operation is interfered with
Solution Approach 1:
The invention separates the RDL formation process from the die by performing it on a carrier substrate, allowing standard front-side lithography to be used on the carrier without interfering with the image sensors on the die. The RDL is then attached to the die in a subsequent step.
Solution Approach 2:
The carrier substrate acts as an intermediary that carries the RDL formation process away from the die, enabling standard lithography processes to be used without exposing the image sensors to process interference while still achieving the required electrical connections.
4Device complexity
If RDL is formed directly on the die, then integration is simplified, but the risk of damaging the die during processing increases
Solution Approach 1:
By forming the RDL on a separate carrier substrate rather than directly on the die, the invention protects the die from exposure to high-temperature and chemically aggressive processing steps. The die is only involved in the final attachment step, significantly reducing its exposure to potential damage.
Solution Approach 2:
The carrier substrate serves as a protective buffer that absorbs the mechanical and thermal stresses of RDL formation processes, shielding the die from potential damage before the RDL is finally attached to the die in a controlled manner.
Data Source
AI summary
Redistribution layers for microfeature workpieces, and associated systems and methods are disclosed. One method for processing a microfeature workpiece system includes positioning a pre-formed redistribution layer as a unit proximate to and spaced apart from a microfeature workpiece having an operable microfeature device. The method can further include attaching the redistribution layer to the microfeature workpiece and electrically coupling the redistribution layer to the operable microfeature device.