Semiconductor Package Singulation via Segmented Cutting Slots
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Solution Overview
Problem
Conventional semiconductor device packaging processes often result in metal burrs during singulation, which can cause electrical shorts due to the sawing process, and also lead to warpage and complexity in attaching electrical contacts.
Innovation Solution
A method involving a heat sink matrix with protruding elements and a package body that encapsulates semiconductor devices, where first cutting slots are made through the heat sink matrix and partially into the package body, followed by second cutting slots through the substrate and package body to singulate the packages, reducing burrs and allowing for precise electrical contact placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional singulation sawing is used to separate semiconductor packages, then productivity is improved through batch processing, but metal burrs are generated at the edges causing electrical shorts
Solution Approach 1:
The singulation process is divided into two distinct stages: first forming cutting slots through the heat sink matrix, then forming second cutting slots through the substrate. This segmentation allows each cutting operation to be optimized independently, with the first slots creating separation paths that guide the second slots to avoid generating harmful metal burrs that could cause electrical shorts.
Solution Approach 2:
The first cutting slots are formed through the heat sink matrix before the second cutting slots are formed through the substrate. This preliminary action creates pre-defined separation paths that guide the subsequent singulation process, ensuring that the final cut follows a controlled trajectory that minimizes burr generation and prevents electrical shorts.
2Ease of manufacture
If heat sink matrix is cut through completely in a single step, then singulation is achieved, but metal burrs are generated and warpage occurs
Solution Approach 1:
The single-step complete cut through the heat sink matrix is divided into two sequential operations: first forming cutting slots through the heat sink matrix only, then forming second cutting slots through the substrate. This segmentation improves edge quality by eliminating excessive burrs and reduces warpage by distributing the cutting stress across two controlled stages.
Solution Approach 2:
The first cutting slots are formed as a preliminary step before the second cutting slots. This preliminary action creates initial separation paths in the heat sink matrix that guide the subsequent substrate cutting, ensuring precise final edge quality and minimizing warpage by pre-establishing the separation geometry.
3Device complexity
If electrical contacts are attached before singulation, then process steps are reduced, but warpage increases due to thermal stress
Solution Approach 1:
The attachment of electrical contacts is separated into different stages corresponding to the two cutting operations. Electrical contacts can be attached after the first cutting slots are formed but before the second cutting slots are completed, or after final singulation. This segmentation allows substrate warpage to be minimized by performing attachment at an optimal point in the process when thermal stress is reduced, while still maintaining reasonable process efficiency.
Solution Approach 2:
The first cutting slots are formed as a preliminary action that creates partial separation before electrical contact attachment. This preliminary separation reduces the overall substrate size and thermal mass, thereby reducing warpage during subsequent contact attachment and reflow processes, while still allowing for efficient batch processing.
Data Source
AI summary
An embodiment of a method for making semiconductor device packages includes a heat sink matrix and a substrate. A plurality of semiconductor devices is attached to the substrate. Then, a package body is formed between the heat sink matrix and the substrate, wherein the package body encapsulates the semiconductor devices. Then, a plurality of first cutting slots is formed, wherein the first cutting slots extend through the heat sink matrix and partially extend into the package body. Then, a plurality of second cutting slots is formed, wherein the second cutting slots extend through the substrate and through the package body to the first cutting slot, thereby singulating the heat sink matrix and substrate into a plurality of individual semiconductor device packages.