Diamond Wafer Cleaving with Offset Laser-Modified Layers
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Solution Overview
Problem
Existing methods for dividing diamond wafers are inefficient due to the high hardness of diamond, leading to rapid tool wear and short tool lifespan, resulting in high costs and improper division of the wafer.
Innovation Solution
A diamond wafer dividing method that forms multiple modified layers within the diamond wafer using a laser beam, allowing for proper division by applying force to the modified regions, which become brittle and facilitate cleavage along the {111} plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a cutting blade is used to mechanically cut the diamond wafer, then the wafer can be divided into small pieces, but the cutting blade is rapidly worn and becomes thin, and the lifetime of the cutting blade becomes extremely short
Solution Approach 1:
The patent replaces the mechanical cutting blade system with a laser beam system. The laser beam irradiates the diamond wafer to form modified layers along planned dividing lines, eliminating mechanical contact and tool wear. This substitution of mechanical processing with optical processing resolves the contradiction between productivity and tool lifetime.
Solution Approach 2:
The patent changes the physical state of the diamond wafer by creating modified layers through laser irradiation. The modified layers have different properties (brittleness) compared to the original diamond structure, enabling division without mechanical cutting. This parameter change allows the wafer to be divided while avoiding tool wear issues.
2Length of stationary object
If multiple modified layers are overlapped in the thickness direction to divide a thick wafer, then the division process can be attempted, but the diamond wafer cannot be necessarily properly divided
Solution Approach 1:
The patent transitions from stacking modified layers in the thickness direction to arranging modified layers in the width direction with overlapping projection areas. This dimensional change in layer arrangement enables proper division of thick wafers by creating intersecting modification patterns that facilitate cleavage along the {111} plane.
Solution Approach 2:
The patent creates modified layers with specific spatial distribution and projection overlap to achieve proper division. The local arrangement of modified layers in the width direction, with overlapping projections, creates specific stress concentrations that guide the division process along the intended dividing lines.
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 method enables efficient and proper division of diamond wafers, reducing tool wear and extending tool lifespan, while ensuring high-quality chip production with reduced costs.
Implementation Method 1
forming a first modified layer at a linear first region along the planned dividing line, inside the diamond wafer by executing irradiation with a laser beam with such a wavelength as to be transmitted through the diamond wafer, in such a manner that the laser beam is focused on the first region
Implementation Method 2
the laser beam is focused on the first region
Data Source
AI summary
There is provided a diamond wafer dividing method used when the diamond wafer having a front surface along the {100} plane is divided at planned dividing lines along the <110> direction. The dividing method includes a first modified layer forming step of forming a first modified layer at a linear first region along the planned dividing line, inside the diamond wafer, a second modified layer forming step of forming a second modified layer at a linear second region shifted from the first region in the width direction and the thickness direction with respect to the front surface, and a dividing step of dividing the diamond wafer along the planned dividing lines by giving a force to the diamond wafer in which the first modified layer and the second modified layer are formed.