Wafer Dicing Alignment and Focus Control Using Surface Height Sensing
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Solution Overview
Problem
Existing dicing devices using laser irradiators cannot adjust the focus of the laser beam on the wafer, limiting their ability to precisely position and process semiconductor chips.
Innovation Solution
A dicing device equipped with a table unit for moving and rotating the wafer, a laser irradiator for emitting a laser beam, an imager for capturing alignment marks, and a height meter for measuring the wafer's surface height, allowing for both horizontal adjustment of the wafer and precise adjustment of the laser beam focus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If only an imaging unit is used to adjust the wafer position, then the horizontal position adjustment is achieved, but the laser beam focus cannot be adjusted
Solution Approach 1:
The imaging unit is enhanced to perform both horizontal position measurement and focus adjustment functions. By detecting the height position of the wafer surface in addition to horizontal coordinates, the single imaging unit serves multiple purposes: positioning the wafer horizontally and adjusting the laser beam focus vertically, eliminating the need for separate measurement devices.
Solution Approach 2:
The measurement capability is extended from two-dimensional horizontal positioning to three-dimensional measurement by incorporating height position detection. The imaging unit now captures not only X-Y coordinates but also Z-axis height information, enabling focus adjustment in the vertical dimension while maintaining horizontal positioning accuracy.
2Productivity
If a laser processing apparatus is used, then dicing capability is provided, but the ability to adjust laser focus on the wafer is lacking
Solution Approach 1:
The imaging unit provides real-time feedback on the wafer surface height position to the control system. Based on this feedback information, the system automatically adjusts the laser beam focus to match the actual wafer surface topography, ensuring precise laser processing while maintaining high productivity in wafer dicing operations.
Solution Approach 2:
Before laser dicing processing, the imaging unit pre-measures the wafer surface height position and the system pre-adjusts the laser focus accordingly. This preliminary measurement and adjustment ensures that when the high-speed dicing process begins, the laser is already optimally focused on the wafer surface, maintaining both precision and productivity.
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
Enables accurate adjustment of the wafer's horizontal position and the laser beam's focus, improving the precision and efficiency of semiconductor chip dicing and processing.
Implementation Method 1
a laser irradiator to emit a laser beam to the wafer moved or rotated while being held by the table unit in order to dice the wafer into the plurality of semiconductor chips
Implementation Method 2
a height meter to measure a height position of the wafer
Data Source
AI summary
A dicing device includes a table unit to move a wafer and rotate the wafer, a laser irradiator to emit a laser beam to the wafer, an imager to image a plurality of alignment marks of a plurality of semiconductor chips on the wafer, and a height meter to measure a height position of a surface of the wafer.