Interferometric microscope

Gluing process

Spot without tools

 

Product description

This microscope assembled by PEM is listed by the group.

Basic elements

The device is built around a basic right metallurgical microscope ( samples are observed in reflected light ).

The base must have at least  :

•  a uniform illumination in white light ;

•  a camera output ;

•  allowing a motor movements in x , y, around z .

To use the scanning interferometry in white light , it is necessary to supplement this equipment as follows  :

•  one or more objectives interferometric (schema) ;

•  a translation system ( engine ) specific and fast of the target or sample along the direction z ;

•  a camera with a high frame rate (> 20 images/s) ;

•  a computer and software acquisition and data processing .

Objectives

To allow characterization of the topography , it is essential to use interferometric objectives . As required, the magnification of these objectives can be adapted in the following ranges:

- Fig. 7b x2.5 et x5,

- Fig. 7a : x10, x20, x50 et x100.

The engine

To obtain high resolution and high speed acquisition , the displacement z is provided by a piezoelectric motor that can move a resolution on the order of nm at a frequency of several hundred hertz. The disadvantage of these systems is their limited dynamic range to several hundred microns .

 

Softwares

The acquisition and data processing are performed in Java (acquisition and processing ) and C + + ( acquisition). These software are developed respectively by the National Institute of Health ( ImageJ ) and the laboratory Vale of the University of California, San Francisco (Micro -Manager ) as well as the entire scientific community that uses them : as it is freeware , the codes are available and it is possible to modify and add plugins for specific uses. This is precisely what we did . A detailed description of the software can be found on the relevant websites :

•  ImageJ http://rsbweb.nih.gov/ij/;

•  Micro-Manager http://www.micro-manager.org/ .

 

 

Diagram showing two types of objectives interferometric : (a) Mirau ; (b) Michelson.

 

Device performances

Characteristics of the

measures

The table II shows the performance achieved in terms of lateral resolution and size of the field investigation along the optical device in place .

Table: Characteristics of images by the optical device .

 

Execution speed

Acquisition speed

The speed data acquisition ( = series of images ) is about 25 to 50 frames per second at VGA format( 640x480 pixels ) . It is mainly limited by the frequency of the piezoelectric motor .

Processing speed

It is between 30 and 100 frames per second ( with a standard low-end PC ) according to the algorithm used which depends on the type of surface to be analyzed

Overall, the speed is at least about 15 seconds or images per seconde is a scanning speed of 1 micron / s in high resolution mode ( step 65 nm ) or 3 microns / s in low resolution ( step 200 nm ). It can reach up to 30 images per second that is to say 2 microns / s in high resolution and 6 microns / s in low resolution

PEM, specialist of gluing before coating, for the achievement of coated tracks on full or precut strips, proposes the sale of its processes , as " turnkey ".

Two distinct technologies are possible :

• Cutting of the adhesive to the desired size after laying on the substrate. In this case , the cutting is done by laser systems .
• Laying of the adhesive to size after cutting in a specific mechanical equipment .

Characteristics of process :

• The details of installation are + - 0.2 mm in both cases.
• Production rates vary by product and number of tracks to achieve, from15 m / min to 40 m / min
• The adhesives used are " standard ", unskilled.

PEM has developed a chemical masking system for producing coatings of small spots . This process may be assigned by PEM , as " turnkey

The principle of the method is as follows :

• Insertion into a classic line of surface treatment, after the stages of implementation of the sub - coating layer , a coating step , followed by a stage of partial removal of the ink previously filed .
• Then after the final stages of coatings ( typically gold plating ) , the process requires the addition of a final stage of ablation and total ink used as masks .

Process Features :

• Speed : Speed calibration based on capacity requirements and the ratio of investment / productivity .
• Geometric accuracy of spot : +-0.15 mm
• Geometric shape of the spot free
  • Spot single or double face possible
  • Slices of hidden parts
• Minimum surface coated : 0.5 mm²