Lead Frame Pad Layout for IC Packaging Parasitic Reduction
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Solution Overview
Problem
As integrated circuit sizes decrease and complexity increases, the length of bond wires and number of downbonds in packaging lead frames increase, leading to significant electrical noise due to parasitic inductance and capacitance.
Innovation Solution
The solution involves arranging electrically conductive I/O and ground circuit pads around an integrated circuit die on a central ground paddle, with bond wires connecting die terminals to these pads to reduce wire length and number of downbonds, thereby minimizing parasitic effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of die terminals and I/O pads is increased to handle greater circuit complexity, then the functionality and capacity of the integrated circuit is improved, but the length of bond wires and number of downbonds increases leading to higher parasitic inductance and capacitance
Solution Approach 1:
The patent segments the bonding process by introducing intermediate bonding points on the lead frame surface. Instead of direct long-distance bonding from die terminals to final I/O pads, the bond paths are divided into multiple shorter segments connected through intermediate pads, reducing the parasitic effects of each individual bond wire while maintaining overall connectivity for complex circuits.
Solution Approach 2:
The patent introduces intermediate I/O pads and ground pads on the lead frame surface as intermediary elements. These intermediate pads serve as mediators that break up long bond wire runs into shorter segments, reducing parasitic inductance and capacitance while still providing the necessary electrical connectivity for high-functionality circuits.
2Productivity
If die size is reduced to achieve higher density packaging, then the packaging capacity is improved, but the relative length of bond wires increases leading to greater parasitic effects
Solution Approach 1:
The patent utilizes the two-dimensional surface of the lead frame more effectively by positioning intermediate I/O pads and ground pads across the surface area. This dimensional utilization allows shorter bond wire paths even when die size is reduced, as the intermediate pads are strategically placed to minimize bond wire length while accommodating higher packaging density.
Solution Approach 2:
The patent applies local quality by creating regions of dense I/O pads and ground pads near the die attachment area. This localized concentration of intermediate bonding points ensures that even small, high-density dies have access to nearby intermediate pads, minimizing bond wire length and parasitic effects while maintaining overall packaging density.
3Reliability
If the number of ground pads and I/O pads is increased to provide more connection points, then the electrical connectivity is improved, but the complexity of the lead frame structure increases
Solution Approach 1:
The patent merges multiple functions into the intermediate pads on the lead frame surface. These pads simultaneously serve as I/O connection points, ground reference points, and intermediate bonding locations. This functional merging increases electrical connectivity and reliability while avoiding the need for separate dedicated structures for each function, thus managing lead frame complexity.
Data Source
AI summary
The disclosure provides integrated circuit packages including a lead frame having multiple I/O pads positioned proximate to the lead frame perimeter around a central ground paddle, an integrated circuit die having electrically conductive die terminals positioned on the central ground paddle, and multiple ground circuit pads positioned on and in electrical connection with the central ground paddle. Electrically conductive I/O circuit pads are arranged about the die between the ground circuit pads and the I/O pads, each I/O circuit pad electrically connected to one of the I/O pads. Electrically conductive bond wires connect one or more of the die terminals to one or more I/O circuit pads or one or more ground circuit pads. In certain embodiments, the disclosure further provides an integrated circuit positioned to engage the integrated circuit die in electrical connection with the die terminals. The disclosure also relates to methods of packaging an integrated circuit to reduce packaging parasitics.