Multi-Layer PCB Alignment via Laser Direct Imaging Compensation
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Solution Overview
Problem
Current manufacturing methods for printed circuit boards face challenges in accurately aligning patterns across multiple layers, particularly with embedded dies, due to limitations in die placement accuracy and alignment systems, leading to inefficiencies in productivity and cost-effectiveness.
Innovation Solution
A method and apparatus for patterning a workpiece using a laser direct imaging system that calculates and compensates for deviations in boundary conditions across layers, allowing for improved alignment accuracy by distributing alignment errors and adjusting pattern data to fit individual dies, enabling more precise and efficient pattern alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional alignment systems are used for multi-layer patterning, then the manufacturing process is simpler, but the alignment accuracy across layers deteriorates
Solution Approach 1:
The system performs preliminary measurement of the first layer pattern before writing the second layer pattern. Alignment transformation parameters are calculated based on these measurements, and the second layer pattern data is pre-transformed using these parameters. This preliminary action ensures high alignment accuracy by accounting for actual layer deviations before the second layer is written.
Solution Approach 2:
The invention replaces complex mechanical alignment systems with a computational approach. Instead of using sophisticated mechanical positioning devices, the system uses measurement data from the first layer, calculates transformation parameters computationally, and applies these parameters to transform the second layer pattern data. This substitution of mechanical systems with computational methods achieves high alignment accuracy while maintaining system simplicity.
2Manufacturing precision
If strict alignment requirements are imposed on all layers, then the alignment accuracy improves, but the productivity decreases due to repeated measurements and adjustments
Solution Approach 1:
The system performs alignment measurements and calculates transformation parameters for the second layer before the actual writing process begins. The pattern data is pre-transformed using these parameters, so that when the second layer is written, it is already optimized for alignment. This preliminary preparation eliminates the need for repeated measurements and adjustments during production, thereby maintaining high alignment precision while improving productivity.
Solution Approach 2:
The alignment system uses measurement data from the first layer itself to generate the transformation parameters needed for the second layer. The system is self-sufficient in determining alignment parameters without requiring external reference standards or additional measurement steps. This self-service approach streamlines the alignment process, reducing cycle time while maintaining accuracy.
3Manufacturing precision
If individual die alignment is performed for each die on the workpiece, then the alignment accuracy to each die improves, but the device complexity and processing time increase
Solution Approach 1:
The system divides the workpiece into individual die regions and performs alignment measurements and transformations for each die separately. The measurement data and transformation parameters are calculated on a per-die basis, allowing the second layer pattern to be precisely aligned to each individual die position. This segmentation approach enables high alignment accuracy to individual dies while using straightforward measurement and calculation methods.
Solution Approach 2:
The alignment transformation parameters are optimized locally for each die region rather than applying a single global transformation to the entire workpiece. The system measures and calculates alignment parameters specific to each die's position and orientation, then applies these local transformations to the corresponding regions of the second layer pattern data. This local quality approach ensures optimal alignment accuracy for each individual die while maintaining system simplicity.
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 enhances alignment accuracy and productivity by allowing for precise pattern alignment across multiple layers, improving the efficiency of the manufacturing process and reducing costs associated with misalignment and rework.
Implementation Method 1
exposing a photoresist or other photosensitive material
Implementation Method 2
a laser scanning the surface with a laser beam that is modulated according to image pattern data
Implementation Method 3
annealing by optical heating
Implementation Method 4
ablating, creating any other change to the surface by an optical beam
Data Source
AI summary
A method of patterning a plurality of layers of a work piece in a series of writing cycles in one or a plurality of write machines, the workpiece being deviced to have a number of N layers and layers of the workpiece having one or a plurality of boundary condition(s) for pattern position, the method comprising the steps of: determining the boundary conditions of layers 1 to N, calculating deviations due to the boundary conditions and calculating a compensation for the deviation of the first transformation added with the assigned part of the deviation due to the boundary conditions.