Lead Frame Sliding Mechanism for Semiconductor Molding Clearance
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Solution Overview
Problem
Existing methods for encapsulating lead frames in semiconductor devices face issues where lateral projections may not block the clearance between the lead frame and the molding die effectively, leading to accidental pinching of larger lead frames and improper resin attachment to terminals.
Innovation Solution
A method involving the use of sliding projections on the dies to crush the lead frame and form lateral projections that block the clearance between the injection surfaces, allowing for controlled resin injection and preventing resin attachment to the lead frame terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the recessed portion is narrowed to reduce the clearance size, then the lateral projections can effectively block the clearance, but larger lead frames cannot be accommodated and may be accidentally pinched between the upper and lower dies
Solution Approach 1:
The lead frame is subjected to preliminary sliding action before the molding process. The sliding means moves the lead frame laterally to reduce the clearance between the lead frame and the side surface of the recessed portion in advance, ensuring that lateral projections can effectively block the clearance without requiring the recessed portion to be narrowly designed, thus accommodating variations in lead frame size
2Adaptability or versatility
If the clearance between the lead frame and the molding die is large, then variations in lead frame size can be accommodated, but lateral projections cannot reach the facing side surface and fail to block the clearance
Solution Approach 1:
The sliding means performs a preliminary action to reduce the clearance before the molding process. By moving the lead frame laterally to align it closer to the side surface of the recessed portion, the system ensures that lateral projections can effectively block the clearance even when the initial clearance is large enough to accommodate lead frame size variations
3Device complexity
If the lead frame is held stationary during molding, then the positioning is simple, but the molding resin attaches to the terminals of the lead frame
Solution Approach 1:
The sliding means performs a preliminary lateral movement of the lead frame to reduce the clearance between the lead frame and the molding die before the molding resin is injected. This preliminary action prevents the molding resin from attaching to the terminals of the lead frame during the molding process, while keeping the positioning mechanism relatively simple
Solution Approach 2:
The sliding means creates a preliminary anti-action by moving the lead frame to a position where the clearance is minimized, thereby preventing the harmful effect of resin attachment to terminals before the molding process begins
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 ensures that the lead frame is not accidentally pinched and prevents resin attachment to the terminals, accommodating manufacturing variations in lead frame size while ensuring reliable resin injection and packaging.
Implementation Method 1
at least one projection formed on the upper die crushes down an end portion of the lead frame so as to form lateral projections
Implementation Method 2
means for sliding the lead frame slides the lead frame toward injection surfaces
Data Source
AI summary
A method of manufacturing a semiconductor device, includes the steps of mounting a lead frame in a recessed portion of a lower die, bringing the lower die and an upper die to overlap each other so that a portion for sliding the lead frame slides the lead frame toward injection surfaces, the sliding portion being formed on the recessed portion of the lower die or on the recessed portion of the upper die, clamping the lower die and the upper die together so that at least one projection formed on the upper die crushes down an end portion of the lead frame so as to form lateral projections on the left and right sides of the gate, the lateral projections blocking up the gap between the injection surfaces and the lead frame, and injecting a molding resin through the gate.