viveknayyar007 :
I am afraid the hardware upgrades are not possible when it comes to laptop computers.
This is not wholly true. In fact, it's mostly inaccurate.
EmaHero,
The upgrade in particular you're inquiring about is not achievable, largely due to the fact that the Yoga 13 does not have the connector for the LED cable that a backlit keyboard uses. Even if the keyboards were interchangeable, you would not be able to take advantage of the backlit feature since your computer lacks the connection required.
All the best!