Termination Products

 

 

 

Polymer Innovations Inc. (PII) produces a line of various products designed for formulating termination pastes. The formulation of the organic portion of an end termination paste can be quite challenging; The final paste must meet many properties such as good green strength and adhesion to avoid pin or abrasion damage during processing of the components. Probably the most daunting challenge is achieving good end termination cosmetics since there are many opposite characteristics which are required. The termination is typically applied to the chip by dipping. The termination must readily wet the chip but not wet the chip to the point of sagging end bands. The termination must flow and level on the chip but not to the point of sagging end bands or exposing the corners of the chip below. The termination must be stable and strong during the drying operation yet readily be removed during firing. The requirement of the organics burning out easily is further complicated by the inert atmospheres required for firing of copper terminations. The organic components of the PII Cu termination kit have been selected to burnout cleanly even in the inert atmosphere used for firing copper. The components of the product line are listed below:

 

 

 

VT06

 

VT06 is a solvent based, clean burn vehicle for use in termination pastes. This vehicle is the main paste component and it consists of both high and low molecular weight resins dissolved in a slow drying mixture of terpineol isomers. VT06 was designed with an emphasis on the higher molecular weight resin which yields higher viscosity for optimal termination pastes. Both resins were selected for their ability to burnout cleanly, even in nitrogen, and to yield a strong and hard 'green' coating. Organic solids are about 40% and formula weight percent is approximately 15%, and thinner is TT01.

 

Note: Viscosity is extremely high at 25°C. Product may require warming to 30-50°C to handle.

 

 

 

TX003

 

TX003 is a totally organic based thixotropic paste designed to modify rheology without changing sintering characteristics. The lack of any inorganic components means this additive leaves NO residue after firing. TX003 should be incorporated through 3 roll milling into the paste, and it is best to let the paste sit for approximately 16 hours to let the viscosity stabilize before measurement. A typical usage level for TX003 is approximately .5 to 2.5% volume weight of the paste, varying by application and desired paste characteristics.

 

 

 

TX001

 

TX001 is a thixotropic paste which serves two functions; its main purpose is to increase the low shear viscosity and thixotropic nature of the paste. TX001 also contains an inorganic additive designed to promote a more controlled sintering of the metal powders added to pastes. This controlled sintering helps prevent firing blisters, increases fired density and can help with final fired coverage of chip corners and edges. In termination pastes TX001 addition does not hamper the initial wetting of the paste during the dipping operation, but it does allow the paste viscosity to go up when the paste comes to rest keeping termination end bands straight and prevents excess sagging during drying.

 

 

 

SC001

 

SC001 is a paste additive which contains a high performance zirconia based additive to modify sintering characteristics of metals. SC001 typically delays the onset of sintering metals and then allows fast densification at a higher temperature. SC001 causes metals to sinter in a more controlled manner similar to ceramics, which typically results in a dense sintered body. A good starting level would be about 2-15% SC001 per total paste formulation weight. Compatible thinner for this product is TT01.

 

 

 

DS007

 

DS007 is an all organic dispersant which works great in pastes and burns out cleanly in any atmosphere. Typical usage level for DS007 is approximately .5 to 2.5% volume weight of the paste, varying by application and desired paste characteristics.

 

 

 

TT01

 

This is a mixed isomer terpineol solvent used in VT06 and used to dilute it further as required. Typical formula weight usage level is approximately 10%, but varies with application.

 

 

 

For More Information on PII's Termination Paste Product Line, click HERE.