Sealing Options Provide Multiple Choices
Catalyst Microtech, dedicated to providing our customers with sealing options, covers a wide range of applications and provides our customers with choices in their assembly process.
Listed below are the sealing methods currently available at Catalyst Microtech:
- Solder Seal - Standard method (Belt furnace)
- Solder Seal - Advanced technology (Vacuum solder reflow)
- Projection welding
- Glob Top
- Plastic Injection Mold
- Prefabricated lids
Solder Seal Processing Requirements
The solder seal process has certain requirements in order to create proper sealing characteristics.
- A low oxygen atmosphere is essential to promote acceptable solder flow. High oxygen levels cause a premature oxidation of the metallized surfaces which inhibits the solder flow.
- A proper temperature profile must match the type of solder used.
Solder Seal - Standard Method (Belt Furnace)
Catalyst Microtech uses a Sikama 8500 - 8 zone furnace (5 heated zones) to perform solder seal operations. This furnace is capable of obtaining <25 ppm oxygen levels. 
Each heated zone has individual set point controls and gas flow controls that maintain platen temperature to within +/- 2°C to ensure consistent and precise temperatures for reliable, repeatable profiles. The gas is introduced through tiny perforations in the conduction heating platens and enters the reflow chamber at the same temperature as the platens.
Solder Seal - Advanced Technology (Vacuum solder reflow)
Solder seal processing through a belt furnace results in 10-15% voiding in the solder. In some applications this may not be acceptable, so a new sealing method has been established that reduces the voiding to less than 2%. This new method of solder sealing, performed in a high vacuum environment, uses a temperature profile to achieve solder reflow
.
Catalyst Microtech delivers on the promise to provide our customers choices with the option of vacuum sealing in our Centrotherm vacuum sealing furnace. With a fully programmable temperature ramp and vacuum cycles, the VLO-300 repeatedly performs void free solder sealing. Additional options include the capability to purge inert or forming gases into the chamber during the sealing profile to enhance seal characteristics.
Projection Welding
Projection welding has been around since the first transistors were packaged and continues to provide a very reliable method of creating a hermetic seal. This method is capable of welding microelectronic and optoelectronic packages: DIP packages, TO's, optical, semiconductor, crystal and custom packages.
Catalyst Microtech uses a Polaris 7100 rotary projection welder to provide this sealing option to our customers.
The environmental chamber is purged with nitrogen and is constantly monitored for moisture levels. The attached bake oven is controlled to provide a moisture prebake before allowing parts to enter the sealing chamber. 
We have invested in the tools required to develop sealing profiles by adding an optional current monitoring system to our sealer. Through the use of the current monitor, we can fine tune and troubleshoot sealing profiles for high yields and repeatable operations.
Glob Top
Many applications don't require a hermetic seal so a plastic encapsulant can be the most economical method to seal and protect the components. Glob Top is a dispensed encapsulation material designed for semiconductor use. Encapsulation materials are designed with different properties and are selected according to your application. This process sometimes involves the dispensing of a damming material which contains the encapsulant and also defines the edges of the package.
The Glob Top process is also used in area array packaging. In this process an array of packages are encapsulated then each device is separated from the substrate using a dicing saw.
Plastic Injection Mold
Catalyst Microtech is dedicated to giving our customers choices in their packaging solutions. We can provide plastic molded packages through the use of our two TOWA CC-S automold machines. These machines are a high volume solution to your plastic packaging requirements. Call Catalyst Microtech to learn more about our plastic mold capabilities.
Prefabricated Lids
In many applications a prefabricated lid can be the most cost effective method to seal and protect your package. These lids are glued in place using a B-staged epoxy and are compatible with a high volume manufacturing process. The lids cost in the range of 0.08 to 0.25 each depending on dimensions. Another added benefit of a prefabricated lid is the ability to rework / repair the devices in the future. This can be a big advantage when working with multi-chip products that require rework / repair ability in the future.