Floating Mold Tooling for Semiconductor Packaging Alignment
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Solution Overview
Problem
Conventional semiconductor packaging using surface-mount technologies faces challenges in increasing the number of leads while maintaining proper alignment and reducing resin bleeding due to limitations in lead spacing and pitch, often resulting in misalignment of mold halves that lead to resin bleeding.
Innovation Solution
The introduction of mold tooling that allows for horizontal movement of mold halves, enabling proper seating and alignment, which includes a clamping plate, cavity bars, and an attachment mechanism that permits horizontal sliding of the cavity bars to align teeth and spaces, thereby preventing resin bleeding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the spacing between leads is decreased to increase the number of leads, then the lead count increases, but the likelihood of leads being shorted together increases
Solution Approach 1:
The patent introduces a second plane for lead arrangement, transitioning from a single-plane two-dimensional layout to a multi-plane three-dimensional configuration. Leads are distributed across multiple planes (first plane, second plane, third plane) with different vertical positions, allowing increased lead density without compromising spacing safety. This dimensional transition enables more leads to be packed into the same horizontal footprint while maintaining adequate clearance between adjacent leads.
2Device complexity
If conventional mold tooling is used with fixed mold halves, then the structure is simple, but misalignment occurs leading to resin bleeding
Solution Approach 1:
The patent transforms the mold tooling from a static fixed-structure to a dynamic adjustable-system. The mold halves are equipped with positioning mechanisms that allow horizontal movement and adjustment during the molding process. This enables the mold halves to be precisely aligned with the lead frame before resin injection, eliminating misalignment issues while maintaining operational simplicity through automated positioning.
3Quantity of substance
If leads are bent to different planes to increase lead count, then the lead capacity increases, but proper alignment during molding becomes difficult
Solution Approach 1:
The patent implements preliminary positioning of leads on multiple planes before the molding process begins. The lead frame is pre-configured with leads arranged on different planes (first plane for some leads, second plane for others, third plane for additional leads), and the mold tooling is pre-adjusted to match this configuration. This preliminary arrangement ensures that when the mold halves are positioned, the leads are already in their correct spatial locations, making the molding process straightforward and eliminating alignment difficulties.
Data Source
AI summary
Tooling for molding a packaged semiconductor device includes a clamping plate, a cavity bar, and an attachment mechanism. The cavity bar has a mold half that has a mold cavity for molding the packaged semiconductor device. The mold half has teeth and a space between pairs of adjacent teeth. The teeth and the spaces support bending of leads of a lead frame of the packaged semiconductor device. The attachment mechanism affixes the cavity bar to the clamping plate and permits the cavity bar to slide relative to the clamping plate. This sliding of the cavity bar enables proper alignment with a mating cavity bar to reduce the likelihood of resin bleed.