Carrier-Foil Copper Foil for Semiconductor Wire Bonding
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Solution Overview
Problem
The existing wire bonding process for semiconductor packages using silver-palladium electrodes is complex and costly, with high manufacturing expenses due to the use of silver paste and expensive equipment.
Innovation Solution
A carrier foil-attached ultra-thin copper foil with a Cu-Al bonding strength improvement layer, a release layer, and a diffusion prevention layer, which simplifies the bonding process and reduces costs by enhancing bonding strength and chemical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If silver-palladium electrodes are used for wire bonding, then bonding strength and conductivity are improved, but manufacturing cost and process complexity increase
Solution Approach 1:
The patent replaces expensive silver-palladium electrodes with a cost-effective copper foil structure that achieves comparable bonding performance. The copper-based carrier foil with controlled surface properties provides sufficient bonding strength without requiring precious metals, significantly reducing material costs while simplifying the manufacturing process
Solution Approach 2:
The patent modifies the surface properties of the copper foil through controlled oxidation and surface treatment to achieve optimal bonding characteristics. By adjusting surface roughness, oxidation state, and chemical composition, the copper foil attains bonding strength comparable to silver-palladium while maintaining cost advantages
2Reliability
If silver paste is used for forming bonding pads, then electrical conductivity is improved, but manufacturing cost increases
Solution Approach 1:
The patent changes the material parameter from silver paste to copper-based materials with controlled surface oxidation. The copper carrier foil's surface is treated to provide adequate electrical conductivity and bonding properties, eliminating the need for expensive silver paste while maintaining functional performance
Solution Approach 2:
The patent employs a composite structure consisting of copper carrier foil with surface oxidation layers and additional copper plating. This composite approach provides both electrical conductivity and mechanical bonding strength without requiring silver-containing materials
3Reliability
If ultrasonic wedge bonding is used for wire bonding, then bonding reliability is improved, but equipment cost and process complexity increase
Solution Approach 1:
The patent replaces complex ultrasonic wedge bonding equipment and procedures with a simpler bonding approach that utilizes the inherent properties of the copper carrier foil. The foiled structure enables direct bonding without requiring expensive ultrasonic equipment or complex wedge bonding processes
Solution Approach 2:
The copper carrier foil's surface properties are designed to enable self-bonding characteristics that reduce or eliminate the need for complex external bonding equipment. The surface oxidation and roughness control allow the material to bond effectively through simpler processes
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
The solution improves bonding strength and reduces manufacturing complexity and costs, while maintaining excellent bonding properties with semiconductor chips and substrates.
Implementation Method 1
the release layer includes a first metal (A3) having a peeling property
Implementation Method 2
the Al layer may be formed through electroplating or sputtering
Implementation Method 3
the Al layer may be formed through electroplating or sputtering
Data Source
AI summary
The carrier-foil-attached ultra-thin copper foil according to one embodiment of the present invention comprises a carrier foil, a release layer, a first ultra-thin copper foil, a Cu—Al bonding strength improvement layer, an Al layer, and a second ultra-thin copper foil, wherein the release layer may comprise a first metal (A3) having peeling properties, and a second metal (B3) and third metal (C3) facilitating the plating of the first metal (A3).