Hi,
First enter stop1 mode (all modules automatically disabled and all pins are input) and check your hardware. If you measure about 100nA in this mode, try to switch STOP3 mode and then
- check you pin directions (no floating)
- close SPI
- close SCI
- close ADC
- close internal bandgap ref
- close rti
- close clock monitor
- close watchdog and internal 1Khz
- close timer1 and 2
that works for me.
Good lucks..