Segmented SCR for high voltage ESD protection

Typical SCR with stripe layout style is modified into segmented one in order to tune the SCR's holding voltage for the ESD protection in different operation voltage domain. SCRs with different segmented style and ratio were made, and according to TLP test results, the most proper one for high voltage ESD protection is selected among them. By delicate layout design and choosing the right segmentation pattern and ratio, the holding voltage of the SCR is obviously lifted to a high level of over 30 V, a high enough value to obtain latch-up immunity.