Multi-Chip Memory Bonding With Protected Alignment Marks
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Solution Overview
Problem
Current memory device technologies face challenges in efficiently manufacturing and integrating magnetic memory devices with precise alignment and high accuracy, particularly in the bonding process of chips, which affects the reliability and yield of the manufacturing process.
Innovation Solution
The proposed solution involves a method for manufacturing magnetic memory devices where two chips are bonded together, utilizing anodic oxidation to form alumina holes with regular and irregular alignment areas, allowing for precise alignment marks and improved alignment accuracy during the lithography process, and using these marks to ensure accurate placement of components like switching elements and reading elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional chip bonding methods are used, then manufacturing process is simpler, but alignment accuracy deteriorates
Solution Approach 1:
Alignment marks are formed on the chips before the bonding process. These pre-formed marks serve as reference points that guide the bonding alignment, ensuring high precision without requiring complex real-time adjustment mechanisms during the bonding operation itself.
Solution Approach 2:
The alignment marks act as intermediary reference elements between the two chips being bonded. By providing visible, pre-defined positional references on both chip surfaces, the marks mediate the alignment process, allowing operators or automated systems to achieve precise positioning without complex measurement equipment.
2Manufacturing precision
If alignment marks are not protected, then manufacturing process is simpler, but alignment mark accuracy deteriorates due to deformation
Solution Approach 1:
The alignment marks are formed and positioned on the chips before the bonding and subsequent processing steps. This preliminary formation ensures that the marks are established at their correct positions before any deformation-prone operations occur, protecting their accuracy throughout the manufacturing process.
Solution Approach 2:
The alignment marks are designed and positioned to withstand subsequent processing steps. By anticipating potential deformation from bonding heat or mechanical stress, the mark design and placement are optimized to maintain accuracy despite these unavoidable process conditions.
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 manufacturing process reliability and yield by maintaining alignment mark accuracy and preventing deformation during anodic oxidation, resulting in improved alignment and reduced substrate handling issues, even with large-diameter wafers.
Implementation Method 1
utilizing anodic oxidation to form alumina holes with regular and irregular alignment areas
Data Source
AI summary
According to one embodiment, a memory device includes: a first chip including a first insulating layer and a first pad; a plurality of memory units provided in a first area of the first insulating layer and arranged at first intervals in a first direction parallel to a surface of the first chip; a plurality of mark portions provided in a second area of the first insulating layer and arranged at second intervals in the first direction; a second chip including a second pad connected to the first pad and overlapping the first chip in a second direction perpendicular to the surface of the first chip; and a circuit provided in the second chip.