Dual-Cut Dicing of Integrated Device Dies to Prevent Metal Stringers
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Solution Overview
Problem
The existing methods for singulating integrated device dies often result in damage and reduced yield due to sawing through substrates, which can cause metal stringers to form, potentially shorting or damaging the device circuitry, and existing solutions fail to effectively prevent corrosion and mechanical issues during the dicing process.
Innovation Solution
A method involving a dual-cut dicing process where a first partial saw cut is made from one side of the substrate and a second complete saw cut from the opposite side, with metal structures in the saw streets acting as sacrificial anodes to prevent corrosion, and optimizing the metal strip width and thickness to minimize stringer formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a substrate is sawn through using a diamond-bladed saw to separate integrated device dies, then the substrate can be divided into individual dies, but the sawing process may damage the substrate and associated integrated device dies, reducing overall yield
Solution Approach 1:
A metal layer is deposited on the substrate surface before the singulation process. This metal layer acts as a sacrificial element that will be removed during sawing, protecting the underlying substrate and device structures from direct mechanical contact and damage by the saw blade.
Solution Approach 2:
The metal layer serves as an intermediary between the saw blade and the substrate. During the singulation process, the saw blade cuts through the metal layer rather than directly contacting the substrate, thereby preventing substrate damage while still achieving die separation.
2Reliability
If metal structures are present in saw streets during dicing, then corrosion can be prevented through sacrificial anode action, but metal stringers may form and potentially short or damage device circuitry
Solution Approach 1:
The width and thickness parameters of the metal layer are optimized to specific ranges. By controlling these dimensional parameters, the metal layer provides adequate sacrificial protection against corrosion while minimizing the formation of excessive metal stringers during the singulation process.
Solution Approach 2:
The metal layer is selectively positioned in the saw street regions where corrosion is most likely to occur. This localized placement provides corrosion protection precisely where needed while minimizing the overall amount of metal present, thereby reducing stringer formation risks.
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
This approach reduces or eliminates metal stringers along the die edges, ensuring smooth and damage-free separation of integrated device dies with reduced risk of short circuits and improved yield by minimizing the length of stringers to less than 100 microns, thereby enhancing the overall singulation process.
Implementation Method 1
metal structures in the saw streets acting as sacrificial anodes to prevent corrosion
Implementation Method 2
sawing through a remaining thickness of the substrate from an opposite side of the substrate along the saw street to physically separate the first integrated device cell and the second integrated device cell
Data Source
AI summary
Integrated device dies and methods for forming one or more of the integrated device dies are disclosed. The integrated device dies can be formed using two step sawing process; a first sawing step partially sawing a substrate comprising metal and a second sawing step sawing through a remaining thickness of the substrate.