Pre-encapsulated etching-then-plating lead frame structure with island and method for manufacturing the same

A lead frame structure for semiconductor packaging, comprising:

• an island and a plurality of leads formed based on a metal substrate by an etching process, wherein the etching process comprises the following steps:
• 1) providing the metal substrate;
• 2) forming a first photoresist film on a top surface of the metal substrate;
• 3) forming a top surface etching pattern in the first photoresist film using photolithography;
• 4) forming a second photoresist film on a back surface of the metal substrate;
• 5) forming a back surface etching pattern in the second photoresist film using photolithography;
• 6) etching the top surface and the back surface of the metal substrate simultaneously using the top surface etching pattern and the back surface etching pattern as the respective masks to form etched regions in the metal substrate, an island, and a plurality of leads;
• and
• 7) removing the first photoresist film and the second photoresist film;
• a molding compound being used to encapsulate the etched metal substrate with the island and plurality of leads by a pre-encapsulation process, wherein the pre-encapsulation process is performed by:
• i) placing the etched metal substrate in a mold;
• and
• ii) encapsulating the etched metal substrate using the mold such that the molding compound is filled in the etched regions, areas between the island and the plurality leads, and areas between the plurality of leads, while exposing top surfaces and back surfaces of the island and the plurality leads;
• and
• a first metal layer and a second metal layer formed on the encapsulated metal substrate by a plating process, wherein the first metal layer is formed on the exposed top surfaces of the island and the plurality leads, and the second metal layer is formed on the exposed back surfaces of the island and the plurality leads.