Metal-Layer Die Marking for Small Semiconductor Substrates
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Solution Overview
Problem
Existing laser etching methods for marking semiconductor components are prone to damage, limited in precision, and unable to accommodate the reduced size and increased information needs of smaller dies, leading to inefficiencies in quality control and identification.
Innovation Solution
A method involving a metal layer on the substrate surface with markings, such as holes or characters, formed within the metal layer, allowing for precise and durable marking that can be viewed from the outer surface using an IR microscope, even on smaller dies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If laser etching is used to mark the die, then the marking process is simple and fast, but the marking is prone to being accidentally removed or made unreadable during grinding steps
Solution Approach 1:
The marking is formed on the cap wafer before the die is mounted and before any grinding steps occur. This preliminary action ensures the marking is established in its final position and protected from subsequent processing steps that could damage it.
Solution Approach 2:
The marking is moved from the die surface to the cap wafer, which is a different spatial dimension in the manufacturing process. The cap wafer serves as a protective carrier that shields the marking from mechanical damage during assembly and testing.
2Productivity
If die size is reduced to accommodate smaller components, then the component density increases, but the available area for marking is reduced
Solution Approach 1:
The marking area is extended to the cap wafer, which has a larger surface area than the die itself. This allows sufficient space for markings even when the die dimensions are reduced, as the marking space is no longer constrained by the die footprint.
3Reliability
If a buffer area is added around the edge of the die to prevent damage, then the die reliability improves, but the available marking area is further reduced
Solution Approach 1:
The marking is relocated to the cap wafer, which extends beyond the die edges and buffer areas. This allows the marking to be positioned in a region that is not constrained by the die's physical boundaries or required buffer zones.
4Measurement precision
If laser etching precision is improved to mark smaller areas, then the marking resolution increases, but the buffer region requirement increases due to inaccuracy
Solution Approach 1:
The marking is formed on the cap wafer before die separation, allowing for more relaxed positioning tolerances. The cap wafer's larger dimensions provide a forgiving workspace that reduces the impact of laser positioning inaccuracies.
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
Enables reliable and space-efficient marking on smaller semiconductor components, reducing the risk of damage and increasing the amount of information that can be marked, while maintaining the functionality of the metal layer as a shielding layer.
Implementation Method 1
the metal layer as a shielding layer
Implementation Method 2
viewed through the cap wafer from an outer surface opposite the inner surface each of the letters and/or numbers are correctly oriented
Data Source
AI summary
A method of marking information on a substrate for use in a semiconductor component is provided. The method comprises providing a substrate for use in a semiconductor component, providing a metal layer on a surface of the substrate, and providing a marking within the metal layer. A method of making a die, a radio-frequency module and a wireless mobile device; as well as a substrate, a die, a radio-frequency module and a wireless mobile device is also provided.