Wire Coating Nozzle for Uniform Silane Coverage in Semiconductor Packaging
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Solution Overview
Problem
Conventional methods for manufacturing semiconductor devices fail to accurately form a primary layer on the outer periphery of wires, including the back surface, leading to weakened bonding strength and potential peeling of the sealant under thermal stress.
Innovation Solution
A method involving a nozzle with a transport wind generating function that spirally swirls the coating liquid downward, ensuring the silane coupling agent-based coating liquid is applied uniformly to the entire circumference of the wires, including the back surface, followed by a drying process to form a primary layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a spinner or sprayer is used to apply coating liquid after the semiconductor element is attached to the case, then the coating process can be performed, but a liquid pool is generated on the inner wall of the case causing insufficient reaction in the film thickness region
Solution Approach 1:
The patent applies coating liquid to the semiconductor element before attaching it to the case, rather than after attachment. This preliminary action prevents the coating liquid from pooling on the case inner wall and ensures uniform distribution on the element surface, resolving both the coating uniformity and reaction completeness issues
2Manufacturing precision
If a pre-coating process is used before the semiconductor element is attached to the case, then coating uniformity is improved, but adhesion between the case and substrate and wire bonding strength are affected
Solution Approach 1:
The patent applies coating liquid selectively to specific regions of the semiconductor element (the regions that will contact the sealant) rather than uniformly to the entire element. This local application ensures adequate coating uniformity where needed while preventing excess coating that would interfere with subsequent bonding processes
3Ease of manufacture
If droplets of coating liquid are applied from above by the atomizer, then the coating process is simple, but the back surface of the wire is not coated causing weakened bonding strength
Solution Approach 1:
Instead of applying coating liquid only from above (vertical direction), the patent rotates the semiconductor element to expose different surfaces including the back surface of the wire to the coating application. This multi-directional approach ensures complete coverage of all surfaces that require coating while maintaining the simplicity of the atomizer method
4Area of stationary object
If coating liquid is applied by scattering in a mist form, then coverage area is increased, but uniform application is difficult and coating may occur in prohibited regions
Solution Approach 1:
The patent employs a coating application method with controlled liquid delivery that monitors and adjusts the coating process to achieve uniform application. By controlling the liquid flow and application parameters, the system ensures coating is applied only to intended regions while maintaining adequate coverage area and uniformity
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 method effectively forms a primary layer on the outer periphery of wires, enhancing bonding strength between the wires and the sealant, thereby preventing peeling during device use and improving thermal resistance.
Implementation Method 1
the nozzle having a transport wind generating function of generating a liquid transport wind that spirally swirls downward, and the coating liquid is supplied to the coating target structure along a flow of the liquid transport wind
Implementation Method 2
The coating liquid contains a silane coupling agent... forms a primary layer on the outer periphery of the wire... enhancing bonding strength between the wires and the sealant
Data Source
AI summary
A coating process of a coating liquid using a nozzle is performed on a coating target structure including a semiconductor element and a wire bonded to the semiconductor element by a wire bonding process. The nozzle has a transport wind generating function of generating a liquid transport wind in a spiral manner. Thus, the coating liquid discharged from the coating liquid supply port of the nozzle is supplied to the coating target structure along the directivity of the liquid transport wind. Then, a drying process is performed on the coating target structure to form a primary layer containing a silane coupling agent as a constituent material on an outer periphery of the wire.