Lead Frame Slot for Integrated Circuit Mold Void Prevention
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Solution Overview
Problem
Integrated circuits face reliability and performance issues due to mold voids and defects, such as weld lines, which can occur during the fabrication of semiconductor die with abutting components, particularly in high-stress applications like magnetic field sensing, where accuracy is critical.
Innovation Solution
Incorporating a lead frame with a die attach paddle featuring a slot that prevents mold voids by allowing the mold material to fill the channel between semiconductor die, ensuring the second surface of the paddle is flush with the mold material, thereby eliminating voids and reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If semiconductor die are abuttingly arranged to form a channel, then device integration is improved, but mold voids and defects occur in the channel
Solution Approach 1:
The die attach paddle is segmented by introducing a slot that divides it into distinct regions. This segmentation allows the mold material to flow through the slot and fill the channel between abutting semiconductor die, preventing mold voids while maintaining the integrated channel structure for device functionality.
Solution Approach 2:
The slot acts as an intermediary feature that facilitates mold material flow into the channel region. By providing this intermediate pathway, the slot enables complete filling of the channel space between die without creating voids, thus mediating between the need for integrated device structure and defect-free molding.
2Reliability
If a slot is added to the die attach paddle, then mold void prevention is improved, but device complexity increases
Solution Approach 1:
The slot is introduced locally at specific positions on the die attach paddle surface, rather than modifying the entire structure. This localized modification provides the necessary function of preventing mold voids while minimizing the increase in overall device complexity by concentrating the structural change only where needed.
3Manufacturing precision
If the channel is completely filled with mold material, then manufacturing precision is improved, but the molding process becomes more difficult
Solution Approach 1:
The slot is pre-formed on the die attach paddle before the molding process. This preliminary action creates a built-in flow pathway that guides the mold material into the channel during molding, making the complete filling process easier and more reliable without requiring complex molding techniques or additional process steps.
Data Source
AI summary
An integrated circuit includes a lead frame having a die attach paddle with a slot extending through the die attach paddle from a first surface to a second surface. A plurality of semiconductor die are positioned such that a channel is formed between the first, second, and third semiconductor die and the slot of the die attach paddle. A mold material encloses the plurality of semiconductor die and at least a portion of the lead frame and is disposed in the channel such that the second surface of the die attach paddle is substantially flush with the mold material. A method of forming an integrated circuit is also provided.