Laser Marking Orientation Flat Lines on Semiconductor Wafers
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Solution Overview
Problem
The challenge in the minimal fab concept for semiconductor manufacturing is the difficulty in forming orientation flat lines and beveling small-diameter wafers without issues during assembly and testing, as the existing methods struggle to effectively create and maintain these features on wafers with diameters of about one-half inch.
Innovation Solution
A method involving the use of a laser beam to form straight groove-like orientation flat lines on a large-diameter wafer before cutting it into smaller wafers, allowing for precise alignment and beveling, which includes lapping the wafer to a thickness of about 350 μm for easier cutting, and subsequent steps like outside diameter finishing, beveling, etching, mirror beveling, polishing, and precision cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If small-diameter wafers are cut out from a large-diameter wafer, then capital investment is reduced and versatility is improved, but orientation flat lines cannot be properly formed and beveling cannot be performed
Solution Approach 1:
The patent applies preliminary action by forming orientation flat lines on the large-diameter semiconductor wafer before cutting it into small-diameter wafers. This ensures that the orientation marks are already present and properly formed on each small wafer after cutting, eliminating the need for separate orientation flat formation steps on each small wafer and solving the problem of inability to form proper orientation flats on small-diameter wafers.
2Ease of manufacture
If small-diameter wafers are used in minimal fab concept, then capital investment is suppressed, but orientation flat or notch cannot be beveled well
Solution Approach 1:
The patent performs beveling of the outer periphery of small-diameter wafers before they undergo etching, mirror beveling, and polishing steps. By conducting the initial beveling operation on the small-diameter wafers after cutting but before subsequent processing, the patent ensures proper bevel formation that would be difficult to achieve on such small wafers, thereby resolving the beveling quality issue while maintaining the capital investment benefits of the minimal fab concept.
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
Facilitates the formation of orientation flat lines on small-diameter wafers, enabling beveling work without problems and improving the handling and processing of these wafers during assembly and testing, while reducing capital investment costs by using smaller, more versatile processing equipment.
Implementation Method 1
a marking step of forming straight groove-like orientation flat lines by a laser beam
Implementation Method 2
a cutting step of cutting out the small-diameter wafers separately from the large-diameter semiconductor wafer by a laser beam
Data Source
AI summary
A method of manufacturing semiconductor wafers which facilitates formation of orientation flat lines and allows beveling work without problems. The method of manufacturing semiconductor wafers includes steps wherein a plurality of small-diameter wafers is cut out from a large-diameter semiconductor wafer, the method including: a marking step of forming straight groove-like orientation flat lines by a laser beam so as to cross the respective small-diameter wafers in each row in the large-diameter semiconductor wafer, wherein cutout positions of the small-diameter wafers are aligned in rows in a specific direction, collectively for each of the rows; and a cutting step of cutting out the small-diameter wafers separately from the large-diameter semiconductor wafer, by a laser beam, after the marking step, in such a way that the orientation flat lines are located at required positions in the small-diameter wafers to be obtained.