Nikon Microscope ME600 with DIC (Differential Interference Contrast)

The microscope is primarily intended for inspection of wafers or chips after development and/or evaporation. It is equipped with an incident (epi) illuminating unit (light is coming from above the specimen) with a Differential Interference Contrast option. It is also equipped with Dark Field option.

Beam-path for Bright-Field illumination in epi mode

Caution! Careful handling of the stage

New computer and framegrabbing software, simple instructions. 2019-05-17.

There is no real calibration for the new framegrabbing software, but if you put the framegrabbing software to full screen two objectives have a measured magnification with 10 % accuracy, see table below. Courtesy Holger Motzkau.

There are five objectives from the Nikon CF Plan BD DIC series with data as follows:

Magnification Numerical Aperture Working Distance [mm] Magnification at full screen
5 × 0.13 10.0 260 ×
10 × 0.3 6.5
20 × 0.46 3.1 1000 ×
50 × 0.8 0.54
100 × 0.9 0.39


Here is the microscope with most of its knobs and switches labeled.

If we start at the lower right corner there are:

If we then go from left to right in the image we have: In summary; the above image shows the microscope set up for bright-field (BF) imaging, the DIC and DF options are disabled. The important settings are:

 


Here is the microscope set up for Dark-Field imaging.
Note the BF/DF switch out, in DF position. The ND-filter is following the BF/DF switch out. Everything else as in the previous picture.

 


DIC imaging setup
Adjust for optimal coloring with knob on Wollastone prism and edge-wheel on DIC polarizer.

The height variations on the sample surface is coded as varying color in the image.

Very roughly described: the DIC polarizer is rotated for the amount of color in the image. Usually the maximum color is when setting the wheel at the dot marker.
The knob for the Wollastone prism is rotated to select what color scale is useful. It ranges from dark bluish to deep reds. Please note that color disappears at the extreme end positions of the knob.

 


A closer view of settings in DIC mode, all labels on microscope are readable

 


The controls for the stage, two ganged knobs for left/right and up/down movement of the stage are visible in the center. Behind them are the focusing controls. Caution! Please be careful when you move the stage to its outer limits. Do not force it against its end-limits. This can cause deformation of the mechanical coupling resulting in play in the stage.

 


Here are all the focusing controls shown and labeled.
From left to right:

 


The focusing controls from another angle.
Also the lamp intensity control is shown. The white button next to it is the "Photo"-switch, it bypasses the intensity control and sets such an intensity that the color balance of the halogen lamp is suitable for true-color photography. This is not very important for DIC-imaging.

 


A DIC image of some patterns made with e-beam lithography.
Imaged with 100X/0.9 objective. Pattern is made on a SiN membrane, 100 nm thick. E-beam resist is ZEP, 120 nm thick, pattern was exposed and developed. The pattern was then filled with 110 nm of Ni by electro-deposition.
Sample courtesy of Anders Holmberg, Biomedical & X-ray Physics, KTH

 


Same sample with different settings of Wollastone prism and DIC polarizer.

 


Same sample imaged with the 50x/0.8 objective.
Also new settings for the Wollastone prism and the DIC polarizer.

 


The whole microscope with CCD-camera

 


The CCD-camera

Anders Liljeborg
NanoFabLab