Side-Extended Chip Contacts for Visible Solder Joint Inspection
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Solution Overview
Problem
Conventional surface mount chips lack the ability for visual inspection of solder joint quality, which is crucial in applications like automotive and medical fields where electrical connection reliability is paramount, and existing methods restrict miniaturization due to bulky connection metallizations.
Innovation Solution
The method involves forming metal contacts on the side of a semiconductor substrate, depositing protective resins, and creating trenches to expose these contacts laterally, allowing for visual inspection of solder joints without the need for bulky frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If connection metallizations are arranged on the lower face side of the chip, then the chip structure is compact, but visual inspection of solder joint quality becomes impossible
Solution Approach 1:
The connection metallizations are extended laterally beyond the flanks of the chip housing, moving from a purely lower-face arrangement to a three-dimensional configuration that protrudes sideways. This dimensional change allows solder joints to be accessed and inspected from the side without compromising the compact lower-face mounting structure.
Solution Approach 2:
The chip structure is segmented into distinct functional zones: the lower face for mounting, the flanks for inspection access, and the upper face for circuit functionality. The connection metallizations are specifically positioned at the flank region, creating a separated inspection zone that does not interfere with other chip functions.
2Difficulty of detecting and measuring
If bulky connection metallizations are used for visual inspection, then solder joint quality can be inspected, but chip miniaturization is restricted
Solution Approach 1:
Only specific regions of the chip (the flanks) are designed with extended connection metallizations for inspection purposes, while the rest of the chip maintains its compact structure. This localized approach to inspection access avoids the need for bulky metallizations across the entire chip, enabling miniaturization while preserving inspection capability.
Solution Approach 2:
The connection metallizations are designed with specific optical properties (reflectivity, color) that enhance their visibility for inspection. The metallization layers are configured to provide sufficient contrast and reflectivity for camera-based inspection systems, eliminating the need for increased size.
3Difficulty of detecting and measuring
If metal contacts extend laterally beyond chip flanks, then visual inspection is enabled, but manufacturing complexity increases
Solution Approach 1:
The connection metallizations are formed to extend laterally during the initial chip fabrication process, before the chip housing is completely encapsulated. This preliminary formation of the inspection-accessible metallizations simplifies subsequent manufacturing steps compared to attempting to add extension features after chip completion.
Solution Approach 2:
The connection metallizations serve multiple functions: providing electrical connection, enabling mechanical attachment, and facilitating visual inspection. This multi-functionality is achieved through a single integrated structure rather than separate components, reducing overall manufacturing complexity despite the extended lateral geometry.
Data Source
AI summary
The present disclosure relates to at least one embodiment of an electronic chip that includes an integrated circuit formed in and on a semiconductor substrate. The flanks of the substrate being coated with a second protective resin. The electronic chip further includes at least one metal contact arranged on a first face of the semiconductor substrate and extending laterally beyond the flanks of the second protective resin. Said at least one metal contact may have a flat connection face extending continuously in part under the semiconductor substrate and extending laterally beyond the flanks of the second protective resin.