Light Emitting Device Package Wire Bonding Reliability
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Solution Overview
Problem
The reliability of wire bonding in light emitting device packages is compromised due to the weakness of secondary bonded portions, which can be broken by external impacts, necessitating an improvement in the bonding process.
Innovation Solution
The use of bonding balls in the wire bonding process enhances the reliability by maintaining electrical connection between the wire and the lead frame, with the first bonding ball positioned on the second lead frame and a second bonding ball positioned above to secure the wire, preventing separation and external impact damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire bonding is performed using conventional methods, then electrical connection is established, but the secondary bonded portion of the lead frame is weak and can be broken by external impact
Solution Approach 1:
The patent applies preliminary action by forming a bonding ball at the end of the wire before the actual bonding process. This bonding ball serves as a pre-prepared strengthening element that will be positioned at the secondary bonded portion of the lead frame, providing enhanced mechanical strength before external impacts can occur.
Solution Approach 2:
The bonding ball acts as an intermediary element between the wire and the lead frame. Instead of directly bonding the wire to the weak secondary bonded portion, the bonding ball serves as a mediator that absorbs mechanical stress and protects the bonded joint from external impacts while maintaining electrical conductivity.
2Ease of operation
If the wire bonded portion of the lead frame is used, then electrical connection is achieved, but external impact can break the wired bonded portion
Solution Approach 1:
The bonding ball provides beforehand cushioning by being positioned at the vulnerable secondary bonded portion. This spherical element absorbs and distributes mechanical stress from external impacts, protecting the wire-to-lead-frame bond from breaking while allowing the bonding process to remain simple and efficient.
3Productivity
If conventional wire bonding is used, then connection is established, but separation of wire from lead frame can occur
Solution Approach 1:
The patent applies parameter changes by modifying the physical form of the wire end from a simple cylindrical shape to a spherical bonding ball. This change in geometry provides a larger bonding surface area and better stress distribution, significantly improving bonding strength and preventing wire separation while maintaining compatibility with existing wire bonding processes.
Data Source
Figure 1
Figure 2~3A
Figure 3B
AI summary
A light emitting device package (100) is disclosed. The light emitting device package (100) includes a light emitting device (130) disposed on a first lead frame (121), the light emitting device (130) having an electrode pad (150) on an upper surface thereof, a first wire (170) to electrically interconnect a second lead frame (122) spaced apart from the first lead frame (121) and the electrode pad (150), and a first bonding ball (190) disposed on the second lead frame (122), the first bonding ball (190) spaced apart from a first contact point (180), which is in contact with the first wire (170) and the second lead frame (122), wherein the first bonding ball (190) is disposed between the first wire (170) and the second lead frame (122) to electrically interconnect the first wire (170) and the second lead frame (122). In the light emitting device package (100), the wire (170) is fixed using the bonding ball (190) upon wire bonding, thereby preventing the wire (170) from separating from the lead frame (122) at the bonded portion therebetween. Also, the wire (170) is electrically connected to the lead frame (122) via the bonding ball (190), thereby improving reliability of wire bonding.