Semiconductor Package Encapsulant Thickness Control
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Solution Overview
Problem
The miniaturization of semiconductor device packages makes individual testing challenging due to instability and rigidity issues, and current molding techniques result in large tolerances in encapsulant thickness, risking package cracks during testing.
Innovation Solution
A method involving a two-stage singulation process using sawing and encapsulant removal to maintain mechanical stability during testing and solder reflow, allowing for controlled encapsulant thickness and efficient package separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If compression molding equipment is used to mold thin mold-caps, then package thickness can be reduced, but tolerances in encapsulant thickness become large which risks package cracks during testing
Solution Approach 1:
The singulation process is divided into two distinct stages: first sawing through the carrier blank to separate individual carriers, then removing encapsulant from the upper surface to achieve final thickness. This segmentation allows each stage to be optimized independently - the sawing stage creates initial separation while the encapsulant removal stage achieves precise final dimensions without risking package integrity.
Solution Approach 2:
The sawing operation is performed first to separate carriers while the encapsulant remains intact and protective. This preliminary action allows the encapsulant to continue providing mechanical support during testing and solder reflow before final thickness reduction, preventing package cracks that would occur if thin encapsulant were created immediately.
2Measurement precision
If individual product testing is performed, then testing accuracy can be maintained, but handling each product one at a time reduces manufacturing efficiency
Solution Approach 1:
Multiple semiconductor devices are mounted on a single carrier blank and processed together through molding, sawing, and testing operations. The encapsulant bonds multiple devices to the carrier, allowing them to be handled as a group rather than individually, thereby maintaining testing accuracy while significantly improving manufacturing efficiency through batch processing.
Solution Approach 2:
The carrier blank acts as an intermediary structure that holds multiple semiconductor devices in a stable array during processing. The encapsulant further mediates by bonding devices to the carrier, enabling group handling and testing while maintaining the positional stability and rigidity needed for accurate individual device testing.
3Length of moving object
If the encapsulant is made thin to reduce package size, then package miniaturization is achieved, but mechanical stability during testing deteriorates
Solution Approach 1:
The sawing operation is performed preliminarily while the encapsulant remains thick and provides mechanical stability. Only after carriers are separated and devices are tested does the encapsulant removal process reduce the thickness to final dimensions. This ensures mechanical stability is maintained during critical testing phases while still achieving miniaturization in the final product.
Solution Approach 2:
The encapsulant thickness reduction is segmented into two phases: first, the encapsulant remains thick during sawing and testing to provide stability; second, encapsulant is removed from the upper surface after testing to achieve final thin dimensions. This temporal segmentation of thickness reduction ensures mechanical stability during testing while achieving miniaturization in the finished package.
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
This method reduces the risk of package damage during testing and allows for precise control of encapsulant thickness, enhancing the stability and efficiency of semiconductor device manufacturing.
Implementation Method 1
sawing into the underside of the carrier blank to saw through the carrier blank and saw partially through the encapsulant
Implementation Method 2
sawing into the underside of the carrier blank to saw through the carrier blank and saw partially through the encapsulant
Implementation Method 3
sawing into the underside of the carrier blank to saw through the carrier blank and saw partially through the encapsulant
Implementation Method 4
sawing into the underside of the carrier blank to saw through the carrier blank and saw partially through the encapsulant
Implementation Method 5
depositing an encapsulant on the die receiving surface, wherein an upper surface of the encapsulant is located above said first height, whereby the encapsulant covers the plurality of semiconductor dies
Implementation Method 6
removing encapsulant from upper surface of the encapsulant at least until said saw depth is reached
Data Source
Figure 1~4
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AI summary
A method of making a plurality of packaged semiconductor devices. The method includes providing a carrier blank having a die receiving surface and an underside. The method also includes mounting a plurality of semiconductor dies on the die receiving surface, wherein the dies extend to a first height above the die receiving surface. The method further includes depositing an encapsulant on the die receiving surface, wherein an upper surface of the encapsulant is located above said first height. The method also includes singulating to form the plurality of packaged semiconductor devices by sawing into the underside, through the carrier blank and partially through the encapsulant to a depth intermediate the first height and the upper surface, wherein said sawing separates the carrier blank into a plurality of carriers, and removing encapsulant from the upper surface of the encapsulant at least until said saw depth is reached.