Not Responding Screen

I have an iPhone 6s+, and i got a issue. Whenever i wanna open the phone using password, the keyboard is not typing, and after a while, it can type again. and that not only unlocking password. whenever i open an app, it will suddenly cannot pressable (like when i want to open someone chat, the screen is not responding). But home button and multitasking bar still working. Is it software problem or hardware problem? can anyone help me with this? Thank you 🙂