Semiconductor Package Lead Frame Layout for Reduced Singulation Spacing
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Solution Overview
Problem
The existing semiconductor package assembly manufacturing techniques require significant spacing between packages on a lead frame due to thick mold cavity walls needed for high-pressure encapsulation, limiting the number of packages that can be processed per lead frame and increasing costs and processing time.
Innovation Solution
A method involving a metallic lead frame with die paddle and terminal columns, where semiconductor die components are attached and encapsulated with a dielectric material, followed by trimming and singulation to reduce spacing between packages, allowing for higher density packaging and increased throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thick mold cavity walls are used to hold dielectric material processing pressure, then encapsulation strength is improved, but the spacing between semiconductor packages increases
Solution Approach 1:
The patent divides the encapsulation process into two distinct stages: first encapsulating multiple semiconductor packages together in a group, then performing singulation to separate them. This segmentation allows the use of thinner cavity walls during group encapsulation since the packages are supported by the mold structure, and the final separation is achieved through controlled breaking or cutting, thus reducing the spacing between packages while maintaining encapsulation strength.
Solution Approach 2:
The patent performs preliminary encapsulation of multiple packages in a group before singulation. By encapsulating packages in groups with thinner cavity walls first, and then separating them afterward, the process achieves reduced spacing without compromising the protective encapsulation. The preliminary group encapsulation provides the necessary structural support during the encapsulation process.
2Ease of manufacture
If significant spacing is left between semiconductor packages, then encapsulation processability is improved, but the number of packages per lead frame decreases
Solution Approach 1:
The patent merges multiple semiconductor packages into groups for simultaneous encapsulation. By combining several packages and encapsulating them together in a single process step using thinner cavity walls, the method increases the number of packages that can be processed per lead frame while maintaining ease of manufacture. The merging approach allows efficient use of the lead frame surface area.
Solution Approach 2:
The patent performs preliminary grouping and encapsulation of multiple packages before singulation. This preliminary action allows the use of thinner cavity walls during the encapsulation process, enabling closer package spacing and higher package density on the lead frame, thereby increasing productivity without sacrificing manufacturing ease.
3Length of moving object
If thinner mold cavity walls are used, then spacing between packages is reduced, but encapsulation processability deteriorates
Solution Approach 1:
The patent segments the encapsulation process into group encapsulation followed by singulation. During the group encapsulation phase, thinner cavity walls can be used because the packages are supported by the mold structure and encapsulated together. The singulation step afterward separates the packages without requiring thick walls, thus achieving reduced spacing while maintaining encapsulation processability through process segmentation.
Solution Approach 2:
The patent performs preliminary group encapsulation with thinner cavity walls before singulation. This preliminary action with reduced wall thickness enables closer package spacing, and the subsequent singulation step completes the process without requiring thick walls, thereby achieving reduced spacing while maintaining ease of manufacture through the preliminary grouping approach.
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 spacing between semiconductor packages, enabling more packages to be manufactured per lead frame surface, reducing costs and processing time, and increasing indexing speed with a higher package density.
Implementation Method 1
The most common encapsulation technique is injection molding of a thermoplastic polymer. This process requires high pressures and temperature
Data Source
AI summary
The present disclosure relates to manufacturing techniques for manufacturing multiple semiconductor package assemblies on a lead frame, as well as a semiconductor package assembly manufactured using this method. The method reduces the distances or intermediate spacings between singulated semiconductor packages on a lead frame to a width equal to the width of a cutting tool which width is significantly smaller than the distance required in any known modelling encapsulation technique. Therefore, the method according to the disclosure allows to position more semiconductor packages on a lead frame on one process step. Accordingly, as the number of semiconductor packages per lead frame surface is increased, more semiconductor packages can be manufactured and singulated in one process step, which reduces costs and processing time.