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Wafer Profilometry Solutions

Surface Profilometer Dyvoce Series The Dyvoce series of surface profilometers is a non-contact profilometry system that uses a laser displacement meter tailored to the workpiece to be measured. The Dyvoce series is equipped with functions designed for ease of use and a simple user interface. The high reliability and motion control technology of this high-precision stage manufacturer enable a wide range of measurements.
Surface profile/thickness measurement system for C to C automatic conveyors【DYVOCE Series】
Manual single wafer type surface profile measuring machine【DYVOCE Series】
DYVOCE Series Technical Information
What wafer warpage measurement can tell us
Ingot shape measurement

Rough crystallinity can be estimated from ingot curvature information.
Dyvoce can also measure the shape of ingots such as SiC.

DYVOCE
Source: Mynavi News, "Development of high-purity powder raw material for sublimation method that enables high-speed growth of SiC single crystals - AIST, etc." https://news.livedoor.com/article/detail/8316076/
Source: AIST, "Large-scale joint research on SiC wafer manufacturing technology development for next-generation power electronics started".
https://www.aist.go.jp/aist_j/news/pr20210309.html
Measurement of wafer shape

By looking at the warpage of wafers, it is possible to improve yield and diagnose the processing process in each process. Wafer warpage is either created during slicing or from the stress difference between the front and back sides of the wafer in subsequent processes. This is due to unevenness in the machining transformation layer created during polishing processes, for example, or film stress on the deposition surface during deposition processes; Dyvoce measurement data can be used to analyze this stress.

Inline Offline Diagnostics

Depending on wafer warpage, there may be cases where the inline process cannot be used. For example, a suction error in the robot hand or the suction plate of the equipment. Dyvoce can mount the work table of a single-wafer machine to imitate the robot hand or the suction plate of each process device, so it is possible to evaluate an inline machine with an offline machine.

Cautions for Wafer Warpage Measurement

As the name implies, a wafer is a thin object, so the shape and amount of warpage of a wafer will vary depending on how the wafer is set against the equipment. This is especially true for wafers with low rigidity, such as large-diameter wafers and thin wafers. This is the reason why it is currently difficult to correlate warp shape and warp amount between different equipment. Therefore, Dyvoce can measure the warpage shape and amount of warpage of a wafer close to the true value by placing the wafer horizontally on three support points in the equipment and correcting for self-weight deflection based on the results of two measurements, one with the surface facing up and the other with the back side facing up. Also, by using model data, self-weight deflection can be corrected even if only one side of the surface is measured.

Shape influenced by support points
Shape corrected for deflection
Stress Analysis Software Film Stress Analysis Software

Using SORI profile measurement data before and after deposition, the software specifies analysis lines in the wafer diameter direction and calculates the film stress distribution according to the radius of curvature and set parameters for each data. It also calculates profile data for each cross-section and outputs a report.

Film Stress Analysis Software
Bare Wafer Stress Analysis Software

Analyzes the stress in a bare wafer based on the shape data of the wafer.

Bare Wafer Stress Analysis Software
What Wafer Thickness Measurement Can Tell Us
Wafer Thickness Measurement

By looking at the thickness of a wafer, it is possible to improve yield in each process and diagnose the processing process. Lack of control of this thickness can lead to focus errors in the exposure process where the wafer is suctioned, etc.

Thickness variation
Film Deposition Thickness Measurement

The GBIR of each deposited film can be measured.

Cautions for Wafer Thickness Measurement

There are various methods of wafer thickness measurement. Each has its own advantages and disadvantages, so care should be taken.

Thickness measurement by site evaluation

Unevenness of thickness at each site when cutting a wafer can be measured.

Site thickness measurement
Glossary of SEMI and SEMI Standard related terms
Bow 3P
Index of the height of the center of a wafer from a three-point reference plane.
Bow BF
Index of wafer center height, height from the least-squares plane.
Warp BF
Difference between the highest and lowest points of a plane passing through the center of the wafer thickness in the FQA and the plane from the least-squares plane.
SORI
Sum of the maximum values of each of the upper and lower normal directions from the least-squares plane. Indicates the warpage of the entire wafer.
FQA (Fixed Quality Area)
An area where flatness and other qualities are guaranteed.
EEA (Edge Exclusion Area)
An area around the periphery of the wafer where flatness and other quality characteristics are not guaranteed. Usually set at 2 mm or 3 mm.
Refractive Index
A quantitative expression of the phenomenon in which the direction in which light travels changes when it passes through the boundary surfaces of different materials. Used as a coefficient when calculating wafer thickness using near-infrared sensors.
Young's modulus
Longitudinal modulus of elasticity. It is a coefficient of proportionality that expresses the proportional relationship between stress and strain in the elastic range, and is called the modulus of longitudinal elasticity.
Poisson's ratio
Poisson's ratio is the ratio of the amount of vertical strain to the amount of horizontal strain.
LTV (local thickness variation)
The difference in absolute values between the maximum and minimum distances from the reference plane to the wafer surface in the interior of each site on the ideal plane. Indicates site-by-site variation.
Gravity Correction
A method used to cancel wafer distortion caused by gravity when measuring wafer SORI. There are three methods: (1) Representative Wafer Inversion Method (2) Sample Wafer Meshod (3) Theoretical Modeling Method.
Representative Wafer Inversion Method
Uses wafers with the same diameter, thickness, fiducial, composition, and crystallographic orientation as gravity correction.
Sample Wafer Meshod
Measures warpage information from the front and back surfaces of a wafer, extracts deflection caused by its own weight, and performs weight deflection compensation.
Theoretical Modeling Method
Gravity correction is performed using the self-weight deflection calculated from a virtual model wafer.
Bessel Point
The point where the deflection of a workpiece is minimized when it is placed on horizontally aligned support points.
Power semiconductors
A semiconductor suitable for using large currents and power.
Diode
A diode with electrodes made by making Pn bonds (SiC, for example, is a specialty of Japan).
Ion Implantation
Using patterned photoresist as a mask, conductive impurities are implanted near the wafer surface Depth and amount of impurities are controlled by varying the implantation energy and the implantation amount per area.
SEMI Standards
A standard set by SEMI that has become the standard for the semiconductor industry worldwide.
3D Mounting
A technology for mounting multiple semiconductor chips, such as memory and microcontrollers, stacked three-dimensionally in a package.
Dicing
A dicing process. Dicing is the process of patterning a circuit on a wafer and cutting it into chips of different sizes.
MEMS
A device that integrates micron-level drive components, etc.
Machine Safety
Machine design to prevent accidents from manufacturing to disposal, even assuming human error and machine breakdown.
Risk Assessment
Machine design and safety measures based on the elimination of unacceptable risks.
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