The customer's challenge

Lithography for advanced packaging is different from lithography for front-end wafer processing. The requirements involved are special and varying. The resist films range from thin to thick. Kulicke & Soffa developed the Liteq 500, a wafer stepper that is flexible and can effectively deal with all these variations and specific needs.

Sioux's contribution

Sioux designed, implemented, and tested the complete software stack for the Liteq 500, including:

  •  the user interface
  • the control software for all devices, including the stage, the CCD camera, the illuminator, the beam stabilizer, the aerial image sensor, and the reticle robot
  • the business logic for processing cells on a wafer, exchanging and aligning wafers, handling reticles, and executing metrology measurements with the projection lens and the CCD camera
  • the mathematical algorithms for the metrology
  • formal verification of the control software using ASD
  • the firmware for Metrology Unit and the Illuminator Control Unit


The first stepper is operational, commercial machines are now being sold.


Windows 8, Microsoft .NET 4.5, WCF, C#, 64 bit, ASD, ESP, STM32 and C++.


Kulicke & Soffa Liteq is the first company to develop a dedicated Lithography solution for the Advanced Packaging market. K&S Liteq provides an innovative and cost-effective wafer stepper addressing current and future requirements.