Hybrid Printing Process Essay, Research Paper
The printing for hybrid circuits is a fundamental process in which the conductors, resistors and overglaze are put onto a ceramic tile called a substrate. While conductors, resistors and overglaze are not printed at the same time, the process is the same. Thus it is very important that anyone who is in the microelectronics field should know the basic process. While the process may change, depending on technology used, the same basic principles will remain.
The printing process requires a few resources. First, the process requires a clean room. Second it requires a hybrid printer. Third, it requires a prepared screen of emulsion with the circuit image on it. Finally, when printing is done you will need a dryer and a furnace.
For materials, the printing process requires a paste. Depending on whether you are printing a conductor, resistor or the overglaze layers; dictates which paste to use.
Once the screen is mounted properly in the printer, the printing process may begin. The spacing between the screen and the substrate is an important element and should be set to the printer s specifications. The reason for the emphasis on spacing is because if the screen is not properly spaced the paste will not peel nicely from the screen.
Once the spacing is checked, the pressure form the squeegee is checked. If the pressure from the squeegee is to great the screen will be damaged and unusable. Once this is set to the screens specifications the printing process may begin.
Squeegee is buttered with a thin coating of paste. Paste is also deposited in a pile before the image of the circuit.
Squeegee travels in a single direction across the screen forcing the paste through the screen onto the ceramic tile or substrate. The screen is also being pushed against the substrate to create a peeling action.
The squeegee lifts relieves pressure off the screen.
Once the printer is done the substrates are allowed to settle for around ten minutes. The reason for the settling is because the paste is thixotropic and it needs time to settle into a uniform shape.
Next the substrates are sent to the dryer and then finally to the furnace where excess materials and impurities are burnt off.
As you can see the printing process has a three major steps. Step one, setup. Step two; actually print the paste through the screen onto the substrate. Step three; fire the result substrate through the dyer and furnace.
Diagrams modified from class notes, from Micro Electronics.