iPhone 6 - 6 Plus Touch Screen U2402 IC
The replacement of this component will solve any occasional malfunctioning of the touch screen. The most effective method to identify any problems related to this ic, is by pressing an icon, wait for it to start 'vibrating' select it without removing your finger and rotate it on the screen, if the app 'is lost' it is recommended to replace the U2402.
Even the so called "zebra effect" is caused by the malfunctioning of this component.

MOTHERBOARD IPHONE 6