Package Substrate Through-Hole Alignment for Segmentation
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Solution Overview
Problem
The existing processing methods for package substrates face challenges in accurately dividing them along scheduled division lines from the sealant side, as alignment marks are typically provided on the bump side, making it difficult to achieve high precision without visible alignment marks on the sealant side.
Innovation Solution
The method involves forming through-holes, through grooves, or division grooves with specific positional relations to the scheduled division lines outside the device regions, allowing for precise alignment and segmentation of the package substrates using these reference features, even without alignment marks on the sealant side, and subsequent formation of conductive shield layers for electromagnetic interference suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the package substrate is held on the bump side for division from the sealant side, then the package substrate can be held stably, but alignment marks cannot be detected and alignment precision deteriorates
Solution Approach 1:
The patent introduces through-holes as intermediary reference features that penetrate the package substrate. These through-holes serve as mediators between the holding requirement and alignment requirement, allowing the substrate to be held on the bump side while providing detectable alignment references on the sealant side through the visible through-holes.
Solution Approach 2:
The patent segments the package substrate into multiple regions by forming through-holes at specific positions. These through-holes create a segmented reference pattern that allows alignment to be performed on the sealant side while maintaining the integrity of the device regions, effectively dividing the alignment function from the device functionality.
2Measurement precision
If alignment marks are provided on the bump side, then alignment can be performed with high precision, but the package substrate cannot be held on the sealant side for division from that side
Solution Approach 1:
The patent transitions the alignment reference from a two-dimensional surface mark to a three-dimensional through-hole structure. By creating holes that penetrate through the substrate thickness, the alignment reference becomes visible from both sides, enabling alignment operations to be performed on the sealant side while maintaining precision.
Solution Approach 2:
Instead of providing alignment marks on the bump side and holding from the bump side, the patent inverts the approach by creating through-holes that enable alignment reference on the sealant side, allowing the substrate to be held on the sealant side for division operations.
3Measurement precision
If through-holes are formed in device regions, then alignment references are available, but the device regions are damaged and device functionality is compromised
Solution Approach 1:
The patent applies local quality by forming through-holes only in non-device regions while preserving device regions intact. Different areas of the package substrate have different properties: device regions maintain their original structure for functionality, while non-device regions contain through-holes for alignment purposes.
Solution Approach 2:
The patent segments the substrate into device regions and non-device regions, with through-holes formed only in the non-device regions. This spatial segmentation allows alignment references to be provided without interfering with or damaging the device regions, maintaining both alignment precision and device functionality.
Data Source
AI summary
A processing method for a package substrate in which a plurality of device chips on a wiring base material are sealed with a sealant includes a through-hole forming step of forming a through-hole in the package substrate so as to have a predetermined positional relation to a scheduled division line and a segmentation step of performing alignment with reference to the through-hole and segmenting the package substrate along the scheduled division line from the sealant side to segment the package substrate into individual packages.