Multi-Gauge Spacer Frame for Semiconductor Package Assembly
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Solution Overview
Problem
The existing process for producing double-sided cooled semiconductor packages is complex, costly, and unreliable due to the individual manufacturing and assembly of AlSiC metal spacers, which can lead to positioning accuracy issues and damage during thermal cycles.
Innovation Solution
A multi-gauge spacer frame with interconnected spacers and tie bars is used, where the spacers are thicker than the tie bars, allowing for improved positioning accuracy and assembly by aligning the frame with a lead frame and substrate, and applying a mold compound to encapsulate the semiconductor dies while leaving tie bars uncovered, enabling efficient double-sided cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If AlSiC metal spacers are individually manufactured and assembled separately, then flexibility in manufacturing is improved, but assembly complexity and time increase significantly
Solution Approach 1:
The patent combines multiple separate spacers into a single integrated spacer frame structure. The frame includes a perimeter portion and multiple spacer portions connected together, eliminating the need to handle and assemble individual spacers separately. This merging approach maintains manufacturing flexibility while dramatically reducing assembly complexity and time.
Solution Approach 2:
The spacer frame serves multiple functions simultaneously: it provides thermal dissipation paths, maintains precise spacing between components, and acts as a structural support element. The integrated design allows a single component to perform what previously required multiple separate operations, reducing assembly steps while maintaining manufacturing adaptability.
2Ease of operation
If separate spacers are used in soldering process, then individual positioning is possible, but positioning accuracy decreases due to spacer movement in molten solder
Solution Approach 1:
By connecting multiple spacers into a rigid integrated frame structure, the patent eliminates the movement problem of individual spacers in molten solder. The frame acts as a single stable unit that maintains precise positioning throughout the soldering process, while still allowing for overall placement adjustment on the semiconductor device.
Solution Approach 2:
The spacer frame is pre-assembled with precise dimensional relationships between spacer portions established before the soldering process. This preliminary positioning ensures that when the frame is placed on the semiconductor device, all spacers maintain their correct positions relative to each other and to the device, preventing movement-induced positioning errors during soldering.
3Ease of manufacture
If spacers are stressed by passivation layer edges, then assembly is simplified, but reliability decreases due to die damage during thermal cycles
Solution Approach 1:
The patent designs the spacer frame with a perimeter portion that specifically addresses the stress issue at the edges. The perimeter portion is configured to contact or be contacted by passivation layer edges without transmitting stress to the semiconductor die, creating a localized stress-management feature that protects the die while maintaining assembly simplicity.
Solution Approach 2:
The perimeter portion of the spacer frame acts as an intermediary element between the passivation layer edges and the semiconductor die. It absorbs or redirects the stress from the passivation layer, preventing it from reaching and damaging the die during thermal cycling, thus protecting the die while allowing the assembly structure to remain simple.
4Adaptability or versatility
If multiple separate components are assembled, then component flexibility is improved, but production time and cost increase
Solution Approach 1:
The patent merges multiple spacer components into a single integrated frame that can be produced as one piece or pre-assembled unit. This reduces the number of assembly operations required during semiconductor device manufacturing, directly improving production efficiency while maintaining the ability to adapt to different device configurations through frame design variations.
Solution Approach 2:
The spacer frame is prepared in advance as a complete, pre-assembled structure with all spacer portions and connecting elements in place. This preliminary preparation allows the frame to be installed as a single unit during device assembly, dramatically reducing production time compared to assembling individual spacers, while still allowing for design flexibility to accommodate different semiconductor device requirements.
Data Source
AI summary
A method of frame handling during semiconductor package production includes: providing a lead frame having leads secured to a periphery of the lead frame by first tie bars; providing a multi-gauge spacer frame having spacers secured to a periphery of the spacer frame by second tie bars, the spacers being thicker than the second tie bars; and aligning the multi-gauge spacer frame with the lead frame such that the spacers and the second tie bars of the multi-gauge spacer frame do not contact the leads of the lead frame. A power semiconductor module and a method of assembling a power semiconductor module are also described.