you need to add the font in all format eot, ttf, woff, svg
try using a service like icomoon
EDIT:
i use this CSS to declare custom fonts and it works in all browsers
@font-face{
font-family: "Font Name";
src:url("fonts/font-name.eot?#iefix");
src:url("fonts/font-name.eot?#iefix") format("eot"),
url("fonts/font-name.woff") format("woff"),
url("fonts/font-name.ttf") format("truetype"),
url("fonts/font-name.svg") format("svg");
}