Semiconductor Alignment Mark Protected by Surrounding Posts
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Solution Overview
Problem
The alignment marks on semiconductor substrates are prone to falling due to external factors such as impacts during handling or transportation, which hinders precise alignment during the dicing process.
Innovation Solution
A semiconductor substrate design featuring a columnar alignment mark surrounded by protection posts with a larger contact area and diameter, where the protection posts are arranged with smaller pitches at the edge and inner sides to securely hold the alignment mark in place, preventing it from falling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a columnar member for alignment is disposed on the semiconductor substrate, then alignment precision is improved, but the columnar member falls due to external factors such as impacts during handling or transportation
Solution Approach 1:
The protection structure is segmented into multiple columnar members (at least three) arranged around the alignment columnar member, with each having a larger contact area with the underlayer. This segmentation distributes the protective function across multiple elements, preventing the alignment mark from falling while maintaining alignment precision.
Solution Approach 2:
The columnar members for protection are formed beforehand with a larger contact area to the underlayer compared to the alignment columnar member. This prior cushioning through enhanced adhesion area prevents the alignment mark from falling due to external impacts during subsequent handling and transportation processes.
2Reliability
If the contact area of protection columnar members is increased to prevent alignment mark falling, then reliability is improved, but device complexity increases
Solution Approach 1:
The columnar members for protection are designed with local quality enhancement - specifically, a larger contact area with the underlayer compared to the alignment columnar member. This localized difference in contact area provides enhanced protection precisely where needed without requiring complex overall structural changes.
Solution Approach 2:
The contact area parameter of the protection columnar members is changed to be larger than that of the alignment columnar member. This parameter change (increased contact area) directly improves reliability by enhancing adhesion and preventing falling, while maintaining a relatively simple overall structure.
Data Source
AI summary
To provide a semiconductor substrate whose columnar member for alignment is difficult to fall off and a manufacturing method thereof. An alignment mark 24 (columnar member for alignment) and protection posts 26 surrounding the alignment mark 24 to protect the alignment mark are disposed in an alignment mark forming region 14 of a semiconductor wafer 101 (semiconductor substrate). Each of the protection posts has a diameter (maximum diameter) of, for example, 0.6 μm. The protection posts 26 are arranged such that the diameter of each of the columnar protection posts 26 is greater than a diameter (for example, 0.2 μm) of the alignment mark 24. That is, the protection posts 26 are arranged such that the contact area between each of the protection posts 26 and an underlayer thereof (dummy wire layer 22) is greater than the contact area between the alignment mark 24 and an underlayer thereof (dummy wire layer 22).