Circuit Board Pad Design for LED Chip Rework
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Solution Overview
Problem
The rework process for LED chip packages on circuit boards often results in damaged copper lines and pads, leading to reduced reliability and yield due to high temperature exposure and the need for disassembly, which complicates the replacement of faulty LED chips.
Innovation Solution
Designing circuit board pads with widths greater than twice the size of the original chip, allowing for direct configuration of substitution chips without disassembling the original chip, thereby simplifying the rework process and maintaining pad integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If the LED chip is stripped from the circuit board during rework, then the faulty chip can be replaced, but the copper lines and pads on the circuit board are probably stripped together, damaging the board and reducing reliability
Solution Approach 1:
The invention segments the pad structure into multiple independent pad regions (first pad, second pad, third pad) with sufficient spacing between them. Each pad is designed with width greater than twice the chip width, creating independent mounting zones. This segmentation allows the chip to be removed without dragging adjacent pads, as each pad maintains structural independence and sufficient clearance from others.
2Ease of repair
If high temperature is applied during the stripping process, then the LED chip can be removed, but the circuit board may expand or shrink unexpectedly, damaging the board
Solution Approach 1:
The invention performs preliminary design action by pre-configuring the pad dimensions and spacing before any rework occurs. The pads are designed with width greater than twice the chip width and appropriate spacing, creating a thermal buffer zone that prevents thermal damage propagation during high-temperature removal processes. This preliminary structural preparation ensures the board can withstand thermal stress without deformation.
3Ease of repair
If the LED chip is stripped using conventional methods, then replacement is possible, but the pads on the circuit board are probably damaged, reducing yield when new chips are packaged
Solution Approach 1:
The invention applies local quality by designing each pad with localized enhanced dimensions (width greater than twice the chip width) and optimized spacing. This creates locally reinforced zones that are specifically prepared to withstand the mechanical stress of chip removal and replacement. The local quality enhancement at pad regions ensures these critical areas remain undamaged during rework, maintaining high manufacturing yield.
Data Source
AI summary
A chip package circuit board module includes a circuit board and an original chip. The circuit board includes a first pad and a second pad disposed besides the first pad and separated from the first pad. The original chip is connected to the first pad and the second pad. A width of the original chip is W1, a total width of the first pad is P1, and a total width of the second pad is P2. The total width P1 of the first pad is larger than twice of the width W1 of the original chip, and the total width P2 of the second pad is larger than twice of the width W1 of the original chip.