Package Carrier Assembly Warpage Control
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Solution Overview
Problem
Semiconductor package strips experience warpage due to thermal expansion mismatches during manufacturing processes, leading to jamming issues and downstream processing problems.
Innovation Solution
A package carrier assembly is used to apply pressure and heat to the package strips during the post mold cure stage, with springs and heat-resistant compressible materials to conform the strips to a shelf, ensuring proper curing and minimizing warpage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If package strips are subjected to temperature variations during processing, then manufacturing processes can be completed, but warpage occurs due to CTE mismatches
Solution Approach 1:
The patent applies pressure to the package strip at the post-mold cure stage, which is a preliminary action taken after molding but before downstream processing. This pressure application prevents warpage from developing during subsequent temperature variations in wire bonding and other processes, rather than correcting warpage after it occurs.
Solution Approach 2:
The patent changes the physical state parameters of the encapsulant by controlling temperature and pressure during the post-mold cure stage. By heating to cure the encapsulant while applying pressure, the material transitions from a soft, moldable state to a cured, dimensionally stable state, preventing warpage during subsequent processing.
2Manufacturing precision
If pressure is applied to conform the strip to the shelf, then warpage is reduced, but additional equipment and process steps are required
Solution Approach 1:
The patent integrates the warpage control function into the existing post-mold cure magazine, which is already part of the manufacturing line. The magazine is modified to include pressure application capability, making it a multi-functional device that both cures the encapsulant and controls warpage, rather than adding a separate warpage control machine.
3Productivity
If warpage control is integrated into the post mold cure process, then workflow interference is minimized, but the curing process becomes more complex
Solution Approach 1:
The patent merges the warpage control function with the post-mold cure process. By applying pressure during the same time period and within the same equipment (the magazine) used for curing, the patent eliminates the need for separate warpage control steps, thereby maintaining workflow efficiency while achieving warpage control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces or eliminates warpage in package strips, minimizing interference with existing workflows and ensuring proper solder ball attachment and processing.
Implementation Method 1
applying pressure to the package strip assembly in selected regions
Implementation Method 2
applying heat of sufficient temperature and for sufficient duration to cure the encapsulant
Implementation Method 3
cure the encapsulant surrounding a plurality of integrated circuits on a strip
Data Source
AI summary
A method for curing an encapsulant that surrounds a plurality of integrated circuits on a strip that forms a strip assembly is provided. The strip assembly is composed of units for packaging and the units each have edges defining a perimeter of the unit. The strip assembly is placed on a shelf. Pressure from deformable material or springs is applied to the strip assembly in regions of the strip. The regions are located at one of a group of locations consisting of along unit edges and centered between unit edges. Heat of sufficient temperature is applied for a sufficient duration to cure the encapsulant. The step of applying pressure continues during the application of heat for curing.