Die Ejector Assembly With Flexible Barrier for Crack-Free Die Separation
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Solution Overview
Problem
Conventional methods for separating singulated dies from dicing tape result in increased defectivity, such as cracks and deformations, especially for thin dies, due to induced pressure points during the separation process, leading to reduced yield and increased manufacturing costs.
Innovation Solution
An apparatus and method using a die ejector assembly with a movable vacuum plate and die ejector, which applies lateral and upward forces to gently separate the dies from the dicing tape, minimizing damage by distributing stress over a larger area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ejector pins with sharp heads are used to push upwardly on the dicing tape, then separation of singulated dies from the tape is achieved, but the pins puncture the tape and contact the die causing cracking or plastic deformation
Solution Approach 1:
The patent employs a flexible membrane that spans across multiple ejector pins. This membrane acts as a protective barrier between the sharp pin heads and the die, distributing the contact force across a larger area and preventing direct puncture of the die. The membrane flexes during the ejection process, allowing upward movement while maintaining contact with the die surface without concentrating stress at discrete points.
Solution Approach 2:
The flexible membrane serves as an intermediary element between the ejector pins and the die. Instead of the pins directly contacting the die, the membrane transmits the ejection force while protecting the die from mechanical damage. This intermediary layer resolves the contradiction by enabling separation functionality while preventing harmful direct contact.
2Ease of operation
If conventional ejection methods are used, then die separation is achieved, but induced pressure points cause marks, scratches, or deformation on thin dies
Solution Approach 1:
The flexible membrane distributes contact pressure across its entire surface area rather than concentrating force at discrete pin locations. This flexible film conforms to the die surface and provides uniform support during ejection, preventing marks and scratches while maintaining operational simplicity.
Solution Approach 2:
The flexible membrane provides cushioning protection before direct contact between ejector pins and die occurs. By placing the membrane in position beforehand, it absorbs and distributes the impact forces, preventing surface damage while maintaining the straightforward ejection process.
3Productivity
If upward ejection force is applied to separate thin dies, then separation is achieved, but the stress induces cracking in fragile thin dies with asymmetric mechanical properties
Solution Approach 1:
The flexible membrane distributes the upward ejection force across the entire die surface rather than concentrating stress at discrete points. This distribution of load prevents localized stress concentrations that would initiate cracks in thin, fragile dies with asymmetric mechanical properties.
Solution Approach 2:
The membrane provides preemptive stress distribution before the ejection force is fully applied. By being in place beforehand, it ensures that the force is evenly distributed from the start of the ejection process, preventing crack initiation in stress-sensitive thin dies.
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
Reduces the number of cracked or deformed dies, enhancing yield and reducing failures during subsequent packaging operations by minimizing stress concentrations on the dies.
Implementation Method 1
a movable vacuum plate configured to engage with a portion of the substrate dicing tape
Data Source
AI summary
Embodiments herein are generally directed to ejection assemblies for singulated dies and thinned wafers and methods related thereto. Die ejection assemblies may be used to minimize cracking or deformation of dies during post-singulation processing. Thus, the die ejection assemblies and methods described herein reduce the number of dies rejected after singulation and the number of failures during a die bonding process. In one general aspect, an apparatus for removing singulated dies from a dicing tape is provided. The apparatus may include a die ejector assembly, which may include a vacuum plate configured to engage with a portion of the dicing tape. A die ejector may be disposed in an ejector opening of the vacuum plate. One or more actuators may be configured to move at least a portion of the die ejector in a lateral direction relative to the upper surface of the vacuum plate.