Wafer Dicing Alignment Using Exposed Macro and Micro Marks
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Solution Overview
Problem
The molding compound used in semiconductor manufacturing obscures scribe lines on wafers, making it difficult for dicing tools to effectively separate individual dies, as these lines are crucial for precise alignment and cutting.
Innovation Solution
Exposing specific areas of the wafer by forming molding compound in a way that allows macro and micro alignment marks to be visible, enabling precise alignment and dicing by distinguishing between different shapes and sizes of marks for macro and micro alignments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If molding compound is applied to protect the wafer and devices, then protection and coverage are improved, but scribe lines become obscured and dicing precision deteriorates
Solution Approach 1:
The molding compound is applied selectively to cover only the die areas while leaving the scribe lines exposed. This local differentiation allows the wafer to be protected where needed (over the devices) while maintaining visibility and accessibility of the scribe lines for precise dicing operations.
Solution Approach 2:
The wafer surface is divided into distinct functional zones: die areas that require protection are covered with molding compound, while scribe line areas that require precision cutting remain exposed. This segmentation enables simultaneous protection and precision cutting capability.
2Object-affected harmful factors
If molding compound covers the entire wafer surface, then comprehensive protection is achieved, but alignment marks become invisible and alignment precision deteriorates
Solution Approach 1:
The molding compound application is localized to specific die areas, intentionally excluding the regions containing alignment marks. This ensures that alignment marks remain visible and accessible for precise alignment operations while the majority of the wafer surface receives protective coverage.
Solution Approach 2:
The wafer surface is segmented into protected die regions and exposed marker regions. This segmentation strategy allows the molding compound to provide comprehensive protection where needed while maintaining visibility of alignment marks for precise measurement and alignment.
3Productivity
If dicing is performed through molding compound, then complete die separation is achieved, but cutting accuracy and tool effectiveness deteriorate
Solution Approach 1:
By leaving scribe lines exposed without molding compound coverage, the dicing tool can accurately locate and follow the precise cutting paths. The exposed scribe lines provide visual guidance for cutting accuracy while the molding compound-covered die areas ensure complete separation when the cut is made.
Solution Approach 2:
The wafer structure is segmented such that scribe lines form exposed pathways through the molding compound layer. This creates clear, visible cutting paths that maintain cutting accuracy while the molding compound provides structural support and enables complete die separation.
Data Source
AI summary
A plurality of macro and micro alignment marks may be formed on a wafer. The macro alignment marks may be formed in pairs at opposite edges of the wafer. The micro alignment marks may be formed to align to streets on the wafer along a first and second direction. A molding compound may be formed on the wafer. The macro alignment marks may be exposed from the molding compound. A pair of the micro alignment marks may be exposed from the molding compound at opposite ends of the streets along the first and the second direction. The wafer may be aligned to a dicing tool using pairs of the macro alignment marks. The dicing tool may be aligned to the streets using pairs of the micro alignment marks. The wafer may be diced using successive pairs of micro alignment marks along the first and second direction.