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GAHA Inspection Solution - LED Manufacturing Application
Measurement Examples
Confocal Laser Scanning Microscopy (CLSM) Principle
Optical sectioning 3D imaging
- depth discrimination
Improved SNR (signal to noise ratio)
- out-of-focus blur rejection
Improved lateral resolution
- up to 1.4 fold
Light from an out-of-focus point is focused on a plane other than the pinhole aperture.

Thus only small portion of this light is detected. This makes the information from out-of-focus points rejected. By doing this, very clear image of thick specimen is achieved. For conventional optical microscopy, clear image of thick object can only be achieved by physically sectioning the object.

For confocal microscopy, this can be done without the physical sectioning.

Due to this optical sectioning ability, confocal can measure clear image of thick specimen and eventually three-dimensional structure of specimen.
Confocal Laser Scanning Microscopy (CLSM) 2D Scan Principle
Point-by-point imaging : 2D image acquisition
Most of confocal microscopy achieves information for only one point of the specimen at a time.

To achieve two-dimensional image of specimen, either the specimen or the focused spot should be moved. In most cases, the spot is moved due to the image acquisition speed.
Confocal Laser Scanning Microscopy (CLSM) 3D Scan Principle
Plane-by-plane imaging : 3D image acquisition
To acquire 3D information of the specimen, either the confocal optics or the specimen should be moved along the axial direction.

The movement of the specimen is not practical in many cases due to some reasons: the movement of the specimen can changes the morphology of the specimen especially in biological applications, and the inertia of the specimen is too large to move the specimen especially in industrial applications. Thus the objective lens is scanned along the axial directions. For fine positioning, the PZT actuator and the stepping motor are usually used. The stepping motor is usually used for coarse positioning due to its relatively long range and high positioning resolution.
Confocal Laser Scanning Microscopy (CLSM) 3D Profiler
Ideally, signal is detected only when the focus is on the surface
Confocal Laser Scanning Microscopy (CLSM) Image Comparison
Normal Microscope Image
2 dimensional Images of confocal microscope are more distinct than normal microscope's images
Confocal Microscope Image
  • Non-contact 3D profile measurement: Laser
    Confocal Scanning Microscope
  • Changeable S/W and GUI as customer’s request
  • The best Nano level 3D Measuring Module
Measurement Examples
  • Micro level 3D Chromatic Confocal Sensor
  • Shape/Surface(2D, 3D), Measuring Depth and Vibration of transparent specimen
  • vPoint Sensor & Line Sensor
  • Application Area : Thickness & Roughness, Level Control, On-line Inspection
Model CL1 CL2 CL3 OP020 OP300VM OP6000
Nominal Measuring range (㎛) 100 300 1100 20 300 6000
Working distance (㎜) 3.3 11 12.7 0.37 5 27.3
Axial resolution (㎛) 0.005 0.012 0.025 0.002 0.010 0.200
Axial accuracy (㎛) 0.02 0.06 0.2 0.010 0.090 03600
Max object slope [deg] +/-43 +/-28 +/-27 +/-48 +/-25 +/-22
  • In line full auto-inspection equipment measuring the height variation of LED Epoxy and Metal Base using 3D inspection module
LED Epoxy Step Measurement
Auto Report
  • In-line Full Automation Inspector of PSS(Patterned Sapphire Substrate) pattern on LED Sapphire Wafers
Need of Auto Analysis Program
Auto Analysis of Sapphire Wafer Bump – Report
Flow Chart with Auto Handler
Specification
Title Specification
Tact Time 112sec/13point
Measuring Method Confocal Method
Repeatability 20 nm (3σ,100XObjective Lens)
Lens Spec.
(100XObjective Lens)
Mag. Max 5,600 Times (24”Monitor, 5times optical zoom)
Optical Zoom 1X ~ 10X
F.O.V. 125 μm X 125 μm
W.D. 0.3 mm
Head Unit Vertical Scan Speed 150 Hz
Vertical Scan Range 100 μm
Vertical Resolution 10 nm
Vertical Repeatability 5 nm
F.O.V Lens Confocal
Scan Actuator PZT (piezo electric actuator)
Feed Back LVDT sensor feedback control
Illumination Laser (wavelength 405 nm)
Controller Maker : PI Piezo controller
X,Y,Z
Stage
Velocity 10 mm/s
Resolution (X,Y) 0.1 μm / (Z) 0.5 μm
Repeatability (X,Y) ±0.1 μm / (Z) ±0.3 μm
Driving Actuator 5 phase stepping motor
Guide LM guide
Controller Suruga Seiki stepping motor
Title Specification
System Work Table Granite based table
Air Suspension Active Isolator with Passive Isolator
Wafer Handling Method Scara Robot with dual Arm
Pre-Aligner 2”, 4” and 6” wafer
OCR 0.023mm/pixel, FOV 15x10.5mm
SECS/GEM Include SECS -2
Software Recipe Yes
Auto Inspect Yes
Result Data Auto Save Yes
Manual Inspect Yes
Profile Analysis Yes
Data Filtering Yes
3D View Yes
Zoom In/Out Yes
  • 3D Measurement of Molding shape of LED Package Chip
  • Micro Measure Module in use(Chromatic Confocal )
Principle of Optical Sensor
Applications of Optical Sensor
Surface of the object
Applications
  • Quality Inspection
  • Microtopography
  • Thickness measurement
  • Roughness measurement
  • Vibrometry
Applications of Optical Sensor
Epoxy Height : the Height from the leadframe to the center of mold cup
  • - Distinguish OK and NG chip
Measuring Example
Epoxy Volume Measurement
  • Auto LED NG Chip Detection, Sorting, Marking
  • Speed(Inspection Time): Chip size: 600um x 600um, 50 secs / wafer (2 inch)