Leadframe Die Pad Marking for Multi-Chip Mounting Verification
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Solution Overview
Problem
Existing semiconductor devices face challenges in accurately confirming the mounting positions of multiple types of semiconductor chips on a leadframe, particularly when different chip sizes and geometries are involved, which complicates the screening of defective products.
Innovation Solution
A method involving a leadframe with distinct marks (recesses or projections) on the die pad to indicate specific mounting regions for each semiconductor chip, allowing for easy identification and inspection of their positions using image processing or sensors, ensuring accurate mounting and visual verification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single leadframe is used for mounting multiple types of semiconductor chips with different sizes and geometries, then the versatility and productivity are improved, but the difficulty of detecting and measuring mounting positions increases
Solution Approach 1:
The die pad is segmented into multiple mounting regions, each designated for specific chip types. Different mark patterns are assigned to different regions, allowing the inspection system to identify and verify each chip type independently based on its corresponding mark pattern.
Solution Approach 2:
Different mark patterns (varying in size, shape, or position) are applied to different local regions of the die pad according to the specific chip types mounted in those regions. This local differentiation enables the inspection system to easily distinguish and verify mounting positions for various chip types.
2Ease of operation
If distinct mark patterns are provided for different semiconductor chip mounting regions, then the ease of operation for inspection is improved, but the device complexity increases
Solution Approach 1:
Asymmetric or distinct mark patterns are provided for different mounting regions instead of uniform marks. These asymmetric patterns enable the inspection system to quickly identify and differentiate between various chip mounting positions, improving inspection efficiency.
Solution Approach 2:
The mark patterns differ in visual characteristics (such as size, shape, or position) that can be easily detected by inspection systems, enabling straightforward identification of different chip mounting regions without requiring complex inspection procedures.
3Manufacturing precision
If the die pad maintains structural integrity and flatness, then the manufacturing precision is improved, but the ease of manufacture of distinct mark patterns may be compromised
Solution Approach 1:
The distinct mark patterns are formed on the die pad during the leadframe manufacturing process before chip mounting. This preliminary formation of marks ensures that the die pad maintains its structural integrity and flatness while the mark patterns are already in place for subsequent inspection.
Solution Approach 2:
The formation of distinct mark patterns is merged with the die pad manufacturing process itself. By integrating mark formation into the leadframe fabrication, the die pad structure is strengthened rather than weakened, and the marks are precisely positioned without compromising manufacturing precision.
Data Source
AI summary
A method of manufacturing a semiconductor device includes mounting at least one of a first semiconductor chip and a second semiconductor chip over a die pad of a leadframe, and inspecting a mounting position of at least one of the first semiconductor chip and the second semiconductor chip, wherein the leadframe includes first mark formed to the die pad, for indicating a first mounting region for the first semiconductor chip, and second mark formed to the die pad, for indicating a second mounting region for the second semiconductor chip, the first mark is different from the second mark, in at least either one of size and geometry, wherein, in the inspecting a mounting position of at least one of the first semiconductor chip and the second semiconductor chip, a mounting position of the first semiconductor chip is inspected when the first semiconductor chip is mounted.