Copper Bonding Wire Surface Oxide Ratio for Low-Scrub Bonding
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Solution Overview
Problem
The use of copper bonding wires in mass production is hindered by low bondability, requiring a special bonding condition with a scrub function, which prolongs bonding time and reduces productivity.
Innovation Solution
A copper bonding wire with a specific surface composition, where the ratio of Cu[II] to Cu[I] falls within a range of 0.8 to 12, as measured by X-ray Photoelectron Spectroscopy (XPS), enhancing bondability without the need for extensive scrubbing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a scrub function is used to improve copper wire bondability, then bonding strength is improved, but bonding time is prolonged and productivity is lowered
Solution Approach 1:
The invention changes the chemical composition parameters of the copper wire surface by controlling the ratio of CuO to Cu2O within specific ranges (0.3≤CuO/(CuO+Cu2O)≤0.6 and 0.2≤Cu2O/(CuO+Cu2O)≤0.5). This parameter optimization enables the copper wire to achieve good bondability without requiring intensive scrubbing, thus resolving the contradiction between bondability and productivity
Solution Approach 2:
The invention performs preliminary oxidation treatment during the wire manufacturing process to create the optimal oxide layer composition before bonding. By pre-establishing the appropriate CuO and Cu2O ratio on the wire surface, the need for extensive scrubbing during bonding is eliminated, improving both bondability and productivity
2Reliability
If a scrub function is used to improve copper wire bondability, then bonding strength is improved, but the process complexity increases
Solution Approach 1:
The invention optimizes the chemical composition parameters of the copper wire surface (controlling CuO and Cu2O ratios within specific ranges), which fundamentally changes the bonding characteristics of copper wire. This enables standard bonding processes to achieve good results without complex scrubbing sequences, reducing device and process complexity
3Quantity of substance
If conventional copper wire is used, then cost is reduced, but bondability is low requiring special bonding conditions
Solution Approach 1:
The invention changes the surface composition parameters of conventional copper wire by controlling the oxide layer (specific CuO and Cu2O ratios), which significantly improves bondability. This allows cost-effective copper wire to be bonded using standard processes without special scrubbing conditions, achieving both low cost and ease of operation
Solution Approach 2:
The invention performs preliminary oxidation during wire manufacturing to create the optimal oxide composition on copper wire surface. This pre-treatment enables conventional copper wire to achieve good bondability without requiring special bonding conditions during operation, maintaining cost advantages while improving ease of use
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 copper bonding wire exhibits favorable bondability even with reduced scrubbing, improving productivity and expanding practical use in semiconductor applications.
Implementation Method 1
when a sum of percentages of Cu, Cu2O, CuO and Cu(OH)2 on a surface of the wire as measured by X-ray Photoelectron Spectroscopy (XPS) is defined as 100%, Cu[II]/Cu[I] which is a ratio of a total percentage of CuO and Cu(OH)2 (Cu[II]) corresponding to bivalent Cu to a percentage of Cu2O (Cu[I]) corresponding to monovalent Cu falls within a range from 0.8 to 12
Data Source
AI summary
There is provided a copper bonding wire that exhibits a favorable bondability even when a scrub at the time of bonding is reduced. The copper bonding wire is characterized in that when a sum of percentages of Cu, Cu2O, CuO and Cu(OH)2 on a surface of the wire as measured by X-ray Photoelectron Spectroscopy (XPS) is defined as 100%, Cu[II]/Cu[I] which is a ratio of a total percentage of CuO and Cu(OH)2 (Cu[II]) corresponding to bivalent Cu to a percentage of Cu2O (Cu[I]) corresponding to monovalent Cu falls within a range from 0.8 to 12.