Welding Pad Repair Coating for Defective SMT Pads
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Solution Overview
Problem
Defective welding pads in the SMT process lead to low product yield and high costs due to issues such as oxidation, damage, and soldering deviations, resulting in scrapped products.
Innovation Solution
A welding-pad repair device and method that includes preprocessing, coating, and encapsulation mechanisms to repair defective pads by de-soldering, removing insulating layers, cleaning, and forming new welding pads with predetermined patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional SMT welding is performed, then assembly efficiency is maintained, but defective pads occur due to oxidation, damage, and soldering deviations
Solution Approach 1:
The patent applies preliminary action by performing preprocessing operations (de-soldering, insulating layer removal, cleaning) on the welding pad area before re-coating the conductive material. This preparatory sequence ensures the surface is properly prepared to receive the new conductive layer, preventing defects caused by improper surface conditions and improving both reliability and yield.
Solution Approach 2:
The patent changes the physical and chemical parameters of the welding pad area through controlled processes: removing the insulating layer to expose traces, cleaning the area to eliminate contaminants, and re-coating with conductive material at controlled thicknesses. These parameter changes transform the defective pad into a functional welding surface, resolving the contradiction between maintaining quality and improving yield.
2Reliability
If defective pads are repaired with multiple preprocessing steps, then welding pad reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple repair functions (de-soldering, insulating layer removal, cleaning, coating, and curing) into a single integrated repair device. The device combines a de-soldering component, insulating layer removal component, cleaning component, coating component, and curing component in one system, reducing the need for multiple separate devices and simplifying the overall repair process while maintaining high reliability.
Solution Approach 2:
The repair device is designed with multi-functionality, where a single device performs all necessary repair operations on the welding pad. The device can switch between different functions (de-soldering, removing insulating layer, cleaning, coating, curing) based on the repair needs, making it a universal solution that handles the complete repair process without requiring multiple specialized devices.
3Area of stationary object
If the insulating layer is removed to expose traces, then contact area is increased, but the risk of contamination increases
Solution Approach 1:
The patent applies preliminary action by performing cleaning operations immediately after insulating layer removal and before re-coating with conductive material. The cleaning component removes any contaminants that may have been exposed during insulating layer removal, ensuring the surface is clean before the new conductive layer is applied. This sequential approach maximizes contact area while eliminating contamination risks.
4Reliability
If conductive material is re-coated to form new pad, then welding pad reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent incorporates feedback mechanisms in the coating process, where the coating component applies conductive material and the curing component then cures it to form the new welding pad. The process includes controlling the coating thickness and pattern through precise delivery mechanisms, and the curing step ensures the material sets to the exact desired configuration. This controlled sequence with built-in verification ensures manufacturing precision while maintaining reliability.
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
Effectively repairs defective welding pads, improving circuit board yield and reducing scrap by increasing contact area and ensuring reliable connections.
Implementation Method 1
a de-soldering component configured for performing de-soldering processing on welding pads at an initial region
Implementation Method 2
the curing component is configured for curing the coated conductive material to form the initial welding pad
Data Source
AI summary
The present disclosure provides a welding-pad repair device and a welding-pad repair method. The device includes: a de-soldering component, an insulating layer removal component and a cleaning component; a welding-pad coating mechanism for forming an initial welding pad, where the welding-pad coating mechanism includes a coating component and a curing component; and a welding-pad encapsulation mechanism for performing an encapsulation operation on a welding pad and a circuit exposed at a periphery of the initial welding pad to form a new welding pad having a predetermined exposure pattern. Embodiments of the present disclosure provide a welding-pad repair device and a welding-pad repair method capable of effectively repairing defective pads before and after dies are bonded, thereby solving problems of low product yield and high cost caused by defective welding pads.