Metallization Scheme as Etching Mask for Wafer Dicing
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Solution Overview
Problem
Conventional wafer dicing methods, such as mechanical sawing and laser dicing, face issues like reduced silicon area, chipping, and quality reliability problems, while plasma dicing lacks integration for bulk and unmetallized dies, and existing etching masks are not suitable for plasma diced wafers.
Innovation Solution
A method involving a metallization scheme as an etching mask, where a gas composition is applied to a wafer with formed metallization areas in die regions, etching away the kerf regions, and reacting with the metallization to create a passivation layer, thereby facilitating precise and reliable die separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mechanical sawing is used for wafer dicing, then die separation is achieved, but silicon area is reduced and chipping damage occurs
Solution Approach 1:
The patent replaces the mechanical sawing system with a plasma-based chemical etching system. Instead of using physical blades to cut the wafer, the invention uses plasma to selectively remove material at the kerf regions, thereby eliminating mechanical contact that causes chipping and reducing the required kerf width to maximize silicon area for active devices.
Solution Approach 2:
The invention changes the fundamental parameter of the dicing process from mechanical force to plasma chemistry. By controlling plasma parameters such as gas composition, power, and pressure, the process achieves precise die separation with minimal material removal and no mechanical stress on the wafer structures.
2Reliability
If conventional etching masks are used in plasma dicing, then etching protection is provided, but integration with bulk and unmetallized dies is not achieved
Solution Approach 1:
The patent makes the metallization layer serve multiple functions: it acts as the etching mask during plasma dicing, provides electrical connectivity for metallized dies, and can be removed or retained based on the specific application requirements. This multi-functionality enables the same process to handle both metallized and unmetallized dies, as well as integrate with bulk semiconductor materials, thereby achieving universal adaptability.
Solution Approach 2:
The invention utilizes the existing metallization structures already present on the semiconductor die to serve as the etching mask, eliminating the need for separate mask deposition and patterning steps. The metallization layer itself performs the masking function it was originally designed for electrical purposes, thereby serving the etching process without requiring additional dedicated masking materials or steps.
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 enhances the precision and reliability of wafer dicing by using the metallization area as a self-aligning mask, reducing damage and increasing the silicon area available for active devices, and allowing for effective integration of plasma diced dies without backside metallization.
Implementation Method 1
applying a gas composition to the wafer, the gas composition etching away the plurality of kerf regions
Implementation Method 2
reacting with the metallization to create a passivation layer
Data Source
AI summary
The various aspects comprise methods and devices for processing a wafer.An aspect of this disclosure includes a wafer. The wafer comprises a plurality of die regions; a plurality of kerf regions between the plurality of die regions; and a metallization area on the plurality of die regions.