Conductive Paste Interconnect for Semiconductor Package
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Solution Overview
Problem
Existing semiconductor packages face limitations in controlling the electrical and thermal connection between the die pad and bond pad, with conventional interconnect methods like wire bonding offering suboptimal resistance and requiring complex clip designs, which can be costly and time-consuming.
Innovation Solution
A method using a cured electrically conductive paste as an interconnect between the die pad and bond pad, allowing adjustable contact areas for enhanced electrical and thermal connections, and a two-step encapsulation process for improved package formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire bonding or clip bond is used for interconnection, then electrical connection is established, but resistance (Rdson) is higher and contact area cannot be adjusted
Solution Approach 1:
The patent changes the physical state and parameters of the interconnect by using conductive paste that can be applied in different volumes and cured to form connections with variable contact areas. This allows optimization of electrical properties (lower Rdson) by adjusting the amount of paste applied, thereby changing the contact parameters between die pad and bond pad.
Solution Approach 2:
The invention uses composite material structure where conductive paste (containing metal particles in a matrix) is applied between die pad and bond pad. This composite approach combines the benefits of adjustable contact area with reliable electrical connection, achieving better electrical properties than traditional wire bonding or clip bond methods.
2Reliability
If clip bond is used, then interconnection is achieved, but design complexity and time to market increase
Solution Approach 1:
The patent extracts the complex clip design element from the interconnection solution and replaces it with a simpler conductive paste application process. By removing the need for precision-engineered metal clips and their associated design, manufacturing, and assembly complexities, the invention achieves reliable interconnection through a more straightforward paste-cure process.
Solution Approach 2:
The invention replaces the mechanical clip bond system (requiring precise mechanical fabrication and assembly) with a material-based solution using conductive paste. This substitution eliminates complex mechanical design while maintaining reliable electrical and thermal connection between components.
3Reliability
If larger contact area is used, then electrical connection improves, but thermal management becomes more challenging
Solution Approach 1:
The patent applies local quality by creating non-uniform contact areas through selective application of conductive paste. Different regions between die pad and bond pad can have different paste volumes and contact characteristics, allowing optimization of electrical connection in critical areas while managing thermal distribution across the entire interface.
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 approach provides better electrical properties, reduced resistance (Rdson), and cost benefits compared to traditional methods, with increased flexibility and faster time-to-market, making it suitable for MOSFET applications.
Implementation Method 1
The cavity is partly filled with an electrically conductive paste, which is subsequently cured to obtain an interconnect
Data Source
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AI summary
There is disclosed a method for producing a semiconductor package. The method comprises providing a lead frame (101) and a bond pad (102) with a space therebetween. The lead frame (101) is provided with a die (103) bonded thereon. The die (103) is provided with a die pad. The die (103), the die pad, a part of the lead frame (101), a part of the bond pad (102) and the space between the lead frame and the bond pad are encapsulated by a first encapsulation (104). Part of the first encapsulation (104) is removed to create a cavity (105) having a bottom surface comprising an exposed surface (106) of the die comprising an exposed surface of the die pad, an exposed surface (107) of the bond pad and a connecting region (108) between the exposed surface of the die paid and the exposed surface of the bond pad. The cavity (105) is partly filled with an electrically conductive paste (109) to cover the bottom surface of the cavity (105). The electrically conductive paste (109) is cured to obtain an interconnect (110) between the die pad and the bond pad. The interconnect (110) is encapsulated by providing a second encapsulation (111) over the interconnect (110).