Laser Diode Electrode Pattern for Wire Bonding Accuracy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-output-power recording laser diodes with long and narrow electrode patterns face challenges in wire bonding due to center line inclination during assembly, leading to non-uniform current density and unstable operation, as Au balls bulge out and are often formed near the edge, causing uneven current distribution.
Innovation Solution
An electrode pattern with specific dimensions, including a shorter sideline, longer sideline, wire-bonding reference pattern, and wire-bonding recognition pattern, where L ≥ 14.3(W−3d/4) and Lb ≤ 14.3(W−3d/4), allowing for accurate wire bonding at arbitrary positions, thereby preventing Au ball bulging and ensuring uniform current distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the electrode is made long and narrow to increase output power, then the optical output increases, but the Au ball bulging becomes more significant and current density uniformity deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-defining a specific electrode pattern geometry with calculated dimensions (L ≥ 14.3(W−3d/4) and Lb ≤ 14.3(W−3d/4)) that anticipates and compensates for the 2° center line inclination occurring during assembly. This pre-designed pattern ensures that even when the Au ball forms at the recognized position rather than the geometric center, the current density remains uniform across the laser diode active region.
2Length of stationary object
If the Au ball is formed near the electrode end portion to reduce bulging length, then the bulging length decreases, but the current density uniformity deteriorates
Solution Approach 1:
The patent applies local quality by creating a non-uniform electrode pattern where the width W and length L are specifically designed to compensate for the Au ball's position away from the geometric center. The pattern has different dimensional characteristics at different locations, with the recognition pattern positioned to account for the expected 2° inclination, ensuring that the current density remains uniform despite the Au ball being formed at a shifted position.
3Adaptability or versatility
If the center line of the laser diode is inclined from the eyelet center line during assembly, then assembly tolerance is accommodated, but the Au ball forms at a shifted position causing current density non-uniformity
Solution Approach 1:
The patent applies preliminary anti-action by designing the electrode pattern with pre-calculated dimensions that counteract the expected 2° center line inclination. The recognition pattern is positioned and sized such that when the Au ball forms at the shifted position due to inclination, the resulting current density distribution remains uniform. This pre-compensation eliminates the harmful effect of the inclination without requiring higher assembly precision.
Data Source
AI summary
An electrode pattern for wire-bonding includes: a wire-bonding reference pattern indicating a reference position for determination of a wire-bonding position; and a wire-bonding recognition pattern. The distance between the reference position and a wire-bonding metal portion bonded to the electrode pattern and the distance between the wire-bonding recognition pattern and the wire-bonding metal portion satisfy predetermined relationships.