This month we feature part 3 of "The challenges of Thick Silicon Epitaxy and solutions” series.

Part 3: "Epi shift and washout solutions”

There are of course a number of possible solutions to solve both “Epi shift” and target washout, but in my opinion the most production worthy is ASML’s 3D align in Back to Back Alignment (BTBA) mode. BTBA mode uses PM targets on the backside of the wafer in conjunction with the 3D alignment system to decouple process from alignment.

 

This approach has been described in a number of publications for various applications including this CMP and thick film Epitaxy - “small times” magazine article.

With this solution, both the “Epi shift” and target washout problems are resolved. Moreover, from a process engineering perspective, BTBA could be used to determine the elusive epitaxy shift factor and mean “Epi shift”. Can you solve the puzzle?

For the answer to the puzzle, or more discussion about the challenges of thick epitaxy, please This e-mail address is being protected from spambots. You need JavaScript enabled to view it. at simaxlithography.com