Waterproof electronic device and manufacturing method thereof

A method for manufacturing a waterproof electronic device, comprising:

• mounting an electronic component including a semiconductor element on a lead frame and bonding electrodes of the semiconductor element and leads of the lead frame;
• providing a heat dissipating member on the lead frame in a thermally conductive manner;
• forming an electronic component module by covering the electronic component and the heat dissipating member with an insulating material in such a manner that a part of the leads of the lead frame extends to outside;
• and
• forming a waterproof film on an outer surface of the heat dissipating member of the electronic component module and at least parts of the insulating material around the heat dissipating member, wherein
• the electronic component module includes an insulating member and an intermediate heat transfer member that are arranged between the lead frame and the heat dissipating member;
• and
• forming the electronic component module includes a step for putting metal powders in a mold and injecting a molten metal material having a lower melting point and lower thermal conductivity than that of the metal powders into a gap between the insulating member and the mold to form the intermediate heat transfer member and the heat dissipating member.