Semiconductor Package Planarization to Limit Warpage and Chipping
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Solution Overview
Problem
Existing package device manufacturing methods face challenges in reducing substrate warpage and preventing chipping or breakage during the removal of mold resin and gap filling members, leading to defective products.
Innovation Solution
A method involving a workpiece preparation with intersecting dividing lines, resin molding, controlled resin thinning, polishing, and dividing to form individual package devices, using a gap filling member with lower thermal expansion than the mold resin, and employing grinding and polishing techniques to avoid exposing fractured layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the mold resin is removed by grinding until the substrate or gap filling member is exposed, then the warpage of the substrate is reduced, but chipping or breakage easily occurs in the gap filling member or substrate
Solution Approach 1:
The patent applies preliminary action by performing a first grinding step to a predetermined depth before the substrate or gap filling member is exposed, then performing a second grinding step with different conditions after exposure. This staged approach prevents chipping and breakage by avoiding direct exposure in a single grinding operation, thus resolving the contradiction between achieving planarity and preventing defects.
Solution Approach 2:
The patent implements periodic action by dividing the grinding process into multiple distinct steps with different grinding conditions. The first grinding step uses initial conditions to remove material up to a predetermined depth, then the second grinding step uses modified conditions (such as different grinding wheel speed, feed rate, or depth of cut) to complete the planarization. This periodic variation in grinding parameters prevents stress concentration and reduces chipping, thereby maintaining both precision and reliability.
2Reliability
If the whole surface of the substrate is coated with mold resin, then the device chips are sealed, but warpage occurs in the whole of the substrate due to shrinkage of the mold resin
Solution Approach 1:
The patent applies local quality by selectively removing mold resin from specific regions (second regions) while maintaining it in other regions (first regions) during the grinding process. This creates a non-uniform distribution of mold resin thickness, which compensates for the shrinkage-induced warpage by providing differential support across the substrate surface, thus resolving the contradiction between sealing quality and substrate flatness.
3Quantity of substance
If the mold resin is ground until the substrate is exposed, then the amount of mold resin is reduced, but chipping or breakage easily occurs in the substrate
Solution Approach 1:
The patent applies preliminary action by performing a first grinding step to a predetermined depth before substrate exposure, establishing a safe margin. Then a second grinding step is performed after exposure with controlled conditions to remove the remaining mold resin. This two-stage approach ensures sufficient mold resin removal while preventing substrate chipping and breakage through progressive material removal.
Solution Approach 2:
The patent implements periodic action by dividing the mold resin removal into distinct grinding phases with varying parameters. The first phase removes the bulk of the mold resin up to a predetermined depth, and the second phase completes the removal after exposure with adjusted grinding conditions. This periodic variation in grinding intensity and parameters maintains substrate integrity while achieving the desired reduction in mold resin quantity.
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 method effectively thins and planarizes the workpiece while preventing chipping or breakage, resulting in high-quality package devices.
Implementation Method 1
polishing the mold resin from the side of the one surface by a polishing pad to expose the second regions of the workpiece
Data Source
AI summary
A package device manufacturing method is provided. In the manufacturing method, device chips are disposed on first regions of a workpiece, and a mold resin is supplied to second regions higher than the first regions and the first regions. Further, the mold resin is processed and thinned to a thickness with which the second regions of the workpiece are not exposed, and the mold resin is polished to expose the second regions of the workpiece and form, in the workpiece, a flat surface including the mold resin and the second regions, the mold resin being disposed on the first regions. Moreover, the workpiece is divided to manufacture the individual package devices.