Semiconductor Packaging with Copper Pad Conversion for Low Resistance
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Solution Overview
Problem
Traditional wire bonding processes in semiconductor packaging face limitations in enhancing product performance and require complex, high-cost bonding pad modifications or Redistribution Layer (RDL) processes, especially with the introduction of blind hole interconnection technology which demands better resistance to acids and bases.
Innovation Solution
A semiconductor packaging method involving the creation of a wire end structure on an aluminum bonding pad using a lead bonding process, followed by encapsulation and thinning to expose the wire bonding pad contact ball, allowing for eutectic fusion and subsequent electroplating or metallization to enhance electrical connections without the need for costly RDL processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire bonding process is used, then traditional packaging can be achieved, but internal resistance is high and heat dissipation ability is insufficient
Solution Approach 1:
The patent replaces the traditional wire bonding mechanical connection with a direct copper-to-copper metallurgical bonding system. The aluminum bonding pad is transformed into a copper bonding pad through electroplating, enabling direct copper wire bonding that provides both electrical connection and heat dissipation function, eliminating the need for separate wire bonding and heat dissipation structures.
Solution Approach 2:
The copper bonding pad structure serves multiple functions simultaneously: it provides electrical connection for signal transmission, acts as a heat dissipation pathway, and enables direct wire bonding attachment. This multi-functional design eliminates the need for separate components and processes.
2Reliability
If blind hole interconnection technology is used, then internal resistance and heat dissipation are improved, but bonding pad modification or RDL operations are required
Solution Approach 1:
The copper bonding pad is formed on the chip surface before wire bonding, allowing direct copper-to-copper bonding without requiring subsequent bonding pad modification or RDL operations. The electroplating process is performed in advance to prepare the bonding surface.
Solution Approach 2:
The invention extracts and eliminates the complex bonding pad modification and RDL operations from the manufacturing process by directly forming a copper bonding pad that is ready for wire bonding, simplifying the overall manufacturing流程.
3Ease of operation
If aluminum bonding pad is used, then traditional wire bonding can be performed, but resistance to acids and bases is poor
Solution Approach 1:
The material composition of the bonding pad is changed from aluminum to copper through electroplating. Copper provides superior chemical resistance to acids and bases while maintaining compatibility with wire bonding processes, thus changing the material parameter to achieve both chemical resistance and bonding compatibility.
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 effectively reduces internal resistance and enhances heat dissipation while avoiding the complexities and costs associated with traditional bonding pad modifications, offering a flexible and cost-effective solution for semiconductor packaging.
Implementation Method 1
Eutectic bonding is realized through aluminum metal and gold wire (according to the principle of eutectic bonding, eutectic bonding is also called low-melting-point alloy welding)
Implementation Method 2
thinning the packaging layer until the wire bonding pad contact ball is exposed
Implementation Method 3
allowing for eutectic fusion and subsequent electroplating or metallization to enhance electrical connections
Data Source
AI summary
The present invention relates to a semiconductor packaging method, comprising mounting a chip on a lead frame, and producing a wire end structure on an AL bonding pad on the upper surface of the chip using a lead bonding process; realizing modification of the AL bonding pad toward gold balls or copper balls to carry out subsequent packaging processes. The method can avoid the limitation of the wire bonding process on enhancing relevant performances of the product, and can avoid the complex and high-cost bonding pad modification or RDL process. The present invention further provides a packaging structure and packaging product obtained using the above method.