Methods of Micro Ball Bumping for Wafer Level and 3-Dimensional Applications Using Solder Sphere Transfer and Solder JettingAuthors: Thomas Oppert, Andrew Strandjord, Thorsten Teutsch, Ghassem Azdasht, and Elke Zakel
Company: Pac Tech
Date Published: 2/14/2012 Conference: Pan Pacific Symposium
To explore this potential, cost-efficient solder bumping technologies for the processing of flip chips on wafer level as well as for 3-dimensional devices have been developed and qualified. The research has shown that the underfill process is one of the most crucial factors when it comes to Flip Chip miniaturization for high reliability applications. Therefore, high performance underfill material was qualified initially .
Wafer level solder application has been done using wafer level solder sphere transfer process against what solder sphere jetting technology was used for other applications than wafer level. Wafer level solder sphere transfer technology uses a patterned vacuum tooling fixture to simultaneously pick up preformed spheres and transfer them all over the wafer at once. The latter is a technique that drops a preformed solder sphere onto the bond pad while simultaneously reflowing the ball in-place using a laser. This tool has been used for many years in the industry, it is commonly known in the industry as a solder ball bumping tool. For the described work the process was scaled down for processing solder spheres with a diameter down to 30 µm.
Besides presenting the above described methods in detail various applications as well as reliability data of assembled flip chips with micro solder bumps according to MIL-STD883G will be shown.
Solder Sphere Transfer, Solder Bumping, Solder Jetting, Flip Chip
Members download articles for free:
Not a member yet?
What else do you get when you join SMTA? Read about all of the benefits that go along with membership.
Notice: Sharing of articles is restricted to just your immediate work group. Downloaded papers should not be stored on an external network or shared on the internet.