Ceramic Copper Circuit Board Surface Control for Reliable Solder Bonding
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Solution Overview
Problem
Insufficient bonding reliability of semiconductor elements on ceramic copper circuit boards due to high nitrogen content at the copper plate surface, which impedes the reaction between the solder layer and the copper plate, leading to poor wettability and bonding integrity.
Innovation Solution
Control the nitrogen amount at the copper member surface to be within a range of not less than 0 at % and not more than 50 at % by employing a cleaning process and controlling the oxygen amount to be within a range of not less than 3 at % and not more than 50 at %, thereby improving the wettability between the copper member and the bonding layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a copper plate is used as the conductor part, then thermal conductivity is improved, but nitrogen adhesion occurs at the surface leading to insufficient bonding reliability
Solution Approach 1:
The patent controls the nitrogen amount at the copper plate surface to be 50 at % or less by adjusting surface treatment parameters and bonding conditions, thereby resolving the contradiction between maintaining copper's thermal conductivity and preventing nitrogen adhesion that compromises bonding reliability
Solution Approach 2:
The patent performs preliminary surface treatment of the copper plate to control nitrogen adhesion before bonding the semiconductor element, ensuring the nitrogen amount is kept at 50 at % or less to prevent bonding failures while preserving thermal conductivity
2Stability of the object's composition
If the nitrogen amount at the copper plate surface is high, then the copper plate maintains its inherent properties, but wettability between the solder layer and copper plate deteriorates
Solution Approach 1:
The patent optimizes the nitrogen amount parameter at the copper plate surface to be 50 at % or less, balancing the maintenance of copper plate composition stability with the improvement of wettability for reliable solder bonding
3Ease of manufacture
If no surface treatment is applied to the copper plate, then manufacturing process is simplified, but bonding reliability becomes insufficient
Solution Approach 1:
The patent implements a controlled preliminary surface treatment to regulate nitrogen adhesion at 50 at % or less, achieving bonding reliability without overly complicating the manufacturing process
Solution Approach 2:
The patent adjusts surface treatment parameters to achieve the optimal nitrogen amount range, balancing manufacturing simplicity with bonding reliability requirements
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
Enhances the bonding reliability of semiconductor elements by preventing nitrogen adhesion and ensuring effective bonding with the solder layer, even at high junction temperatures, reducing delamination and cracks, and maintaining thermal conductivity.
Implementation Method 1
Control the nitrogen amount at the copper member surface to be within a range of not less than 0 at % and not more than 50 at % by employing a cleaning process
Implementation Method 2
A solder layer or a silver paste is used to mount the semiconductor element. The solder layer or the silver paste secures the bond between the ceramic copper circuit board and the semiconductor element
Data Source
AI summary
According to an embodiment, a ceramic copper circuit board in which the reliability of bonding with a bonding layer is improved is provided, and an insulating circuit board includes an insulating substrate and a conductor part bonded to at least one surface of the insulating substrate. In XPS analysis of a nitrogen amount at the conductor part surface, an average value of the nitrogen amount at any three locations is within a range of not less than 0 at % and not more than 50 at %. In XPS analysis of the oxygen amount at the conductor part surface, the average value of the three locations is favorably within the range of not less than 3 at % and not more than 30 at %. The ratio of the nitrogen amount to the oxygen amount is favorably not less than 0 and not more than 5.