Asymmetric Wafer Scribe Layout for Higher Memory Die Density
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Solution Overview
Problem
The existing fabrication processes for memory devices result in significant material loss due to uniform scribes, leading to inefficiencies in resource utilization and increased costs, as the scribes do not optimize the number of circuits printed on a wafer.
Innovation Solution
Implementing scribes of varying widths and alternating patterns to separate memory dies, with active and dicing scribes having different widths in both directions, allowing for more efficient use of wafer material and reducing material loss during the fabrication process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If uniform scribes are used to separate memory dies, then die separation is achieved, but significant material loss occurs reducing fabrication efficiency
Solution Approach 1:
The patent applies asymmetry by implementing non-uniform scribe widths across the wafer. Different scribe regions have different widths: first scribes have a first width, while second scribes have a second width that is narrower than the first. This asymmetric design allows optimization of material usage while maintaining adequate separation where needed, directly resolving the contradiction between die separation and material loss.
Solution Approach 2:
The patent implements local quality by varying scribe characteristics based on location. Active scribes that require die separation maintain larger widths, while dicing scribes in regions where separation is less critical use narrower widths. This localized optimization reduces overall material loss while preserving necessary separation functions in critical areas.
2Loss of substance
If narrower scribes are used to reduce material loss, then material efficiency improves, but die separation and integration capabilities may be compromised
Solution Approach 1:
The asymmetric scribe width design ensures that critical separation functions are maintained in active scribes with larger widths, while non-critical areas use narrower scribes for material efficiency. This resolves the contradiction by providing adequate separation capability where needed without unnecessarily wasting material in areas where separation is less important.
Solution Approach 2:
Different scribe regions are assigned different quality levels based on their functional requirements. Active scribes maintain larger widths to ensure reliable die separation, while dicing scribes use narrower widths for material efficiency. This localized differentiation maintains separation reliability in critical areas while improving overall material efficiency.
3Productivity
If more circuits are printed per wafer to increase productivity, then fabrication efficiency improves, but scribe material loss increases
Solution Approach 1:
The asymmetric scribe width configuration allows tighter packing of circuits on the wafer by using narrower scribes in appropriate regions. This increases the number of circuits that can be printed per wafer while minimizing the total scribe material, directly addressing the contradiction between productivity and material loss.
Solution Approach 2:
By optimizing scribe widths locally based on circuit density requirements, the patent enables higher overall circuit density on the wafer. Narrower scribes in low-priority areas allow more circuits to be packed, while maintaining adequate separation in critical regions, thus increasing productivity without excessive material loss.
Data Source
AI summary
Methods, systems, and devices for techniques for forming a device with scribe asymmetry are described. Circuits (e.g., arrays of memory cells) may be printed on a wafer and separated by scribes of various widths to increase an array efficiency of a fabrication process. For example, a scribe that extends in a first direction may have a width in a second direction. A first subset of scribes may have a first width, where one or more structures may be placed in the first subset of scribes to facilitate die testing and integration. A second subset of scribes may have a second width. In some examples, the structures may not be placed in the second subset of scribes and, accordingly, the second width may be less than the first width.