Previous IC packages had spacious rooms (from edge to ball) to hold IC packages with shelf, however, nowadays, the distance from edge to ball getting smaller and smaller, issues of IC packages being fallen off of shelf and got stuck inside shelf are being seen more and more.
Weights of IC packages so light that it cannot lift up themselves & recover the original position.
Because of this patented angle inside the shelf, IC packages slides up the angle smoothly and recover the original sitting place.
