LED Package Standby Bonding Pads for Wire-Bonding Yield
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Solution Overview
Problem
The existing LED package structures face inefficiencies in wire-bonding due to incorrect connections between wires and pads, leading to increased wire-bonding time and decreased yield, as manufacturers often need to clean solder splashes before reattempting connections.
Innovation Solution
The proposed LED package structure incorporates at least two positive and negative pads for each LED bare chip, allowing for standby connections without cleaning, thereby reducing wire-bonding time and enhancing yield by enabling wire connections to alternate pads if the initial connection fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If only one positive pad and one negative pad are provided for each LED bare chip, then the device structure is simple, but wire-bonding yield decreases and wire-bonding time increases when connection fails
Solution Approach 1:
The patent applies local quality by providing multiple pads (at least two positive pads and at least two negative pads) for each LED bare chip electrode, where each pad serves as a potential bonding target. This local redundancy ensures that if one pad connection fails, alternative pads are available, thereby increasing wire-bonding yield without requiring complete structural redesign
Solution Approach 2:
The patent implements beforehand cushioning by pre-providing standby pads that can serve as backup connection points. These standby pads are prepared in advance during substrate fabrication, so when wire-bonding fails on the first attempt, the manufacturer can immediately re-bond to a standby pad without needing to clean solder splashes or perform additional preparation steps
2Reliability
If wire connection fails and cleaning is required before reconnection, then connection reliability can be improved, but wire-bonding time increases and efficiency decreases
Solution Approach 1:
The patent applies preliminary action by pre-preparing multiple pads on the substrate before the wire-bonding process. The standby pads are fabricated and positioned in advance, so when a wire-bonding attempt fails, the manufacturer can immediately proceed to re-bonding on a standby pad without requiring cleaning or other preparatory actions, thus maintaining high wire-bonding efficiency
Solution Approach 2:
The patent uses copying by creating multiple identical pad structures (positive pads and negative pads) on the substrate. Each LED bare chip has at least two positive pads and two negative pads as copies, providing redundant bonding targets that can be used if the original bonding attempt fails, eliminating the need for cleaning operations
3Ease of operation
If multiple pads are provided for each LED bare chip, then wire-bonding yield increases and reconnection is easier, but the device structure becomes more complex
Solution Approach 1:
The patent applies universality by designing the substrate with a standardized pad structure where multiple pads serve the same function (electrical connection to LED electrodes). The multiple positive pads and multiple negative pads are universally interchangeable, allowing the wire-bonding process to proceed to any available pad of the correct polarity, thereby simplifying reconnection operations despite the increased number of pads
Data Source
AI summary
An LED package structure with standby bonding pads for increasing wire-bonding yield includes a substrate unit, a light-emitting unit, a conductive wire unit and a package unit. The substrate unit has a substrate body and a plurality of positive pads and negative pads. The light-emitting unit has a plurality of LED bare chips. The positive electrode of each LED bare chip corresponds to at least two of the positive pads, and the negative electrode of each LED bare chip corresponds to at least two of the negative pads. Each wire is electrically connected between the positive electrode of the LED bare chip and one of the at least two positive pads or between the negative electrode of the LED bare chip and one of the at least two negative pads. The package unit has a light-permitting package resin body on the substrate body to cover the LED bare chips.