Semiconductor device and die bonding structure thereof

A semiconductor device comprising:

• a semiconductor die;
• a barrier layer formed on a surface of the semiconductor die;
• a first metal layer formed on the barrier layer;
• a central metal layer formed on the first metal layer;
• and
• a second metal layer formed on the central metal layer,
• wherein the first and second metal layers have a first melting temperature, and the central metal layer has a second melting temperature lower than the first melting temperature,
• wherein thicknesses of the central metal layer, the first metal layer and the second metal layer range in a descending order:
• central metal layer >first metal layer >second metal layer.

A die bonding structure comprising:

• a semiconductor die;
• a lead frame electrically connected to the semiconductor die;
• and
• a tin silver (SnAg) alloy electrically connected to the semiconductor die and the lead frame,
• wherein a die bonding temperature of the tin silver alloy is in a range of 220° C. to 450° C., and a remelting temperature of the tin silver alloy is in a range of 280° C. to 500° C.