Lead wire frame and production method thereof

Abstract

The invention relates to the field of electronic packaging manufacturing, in particular to a lead wire frame for packaging a chip. Particularly, the lead wire frame is mainly applied to an SOT (Small-outline Transistor) series. A production method of the lead wire frame comprises the steps of A) stamping, B) electroplating and C) forming, wherein in Step A), a copper alloy sheet is taken for stamping through a male die and a female die of a cutting die to form a semi-finished lead wire frame; the tensile strength Rm of the copper alloy sheet is greater than or equal to 600MPa; the elongation after rupture A11.3 is greater than or equal to 8%; the vickers hardness HV is greater than or equal to 180; the electrical conductivity is greater than or equal to 46% IACS (International Annealed Copper Standard); and the thermal conductivity is greater than or equal to 190w / m*k; in Step B), the semi-finished lead wire frame is subjected to the following treatment sequentially: namely preelectrosilvering, electrosilvering and silver drawing; and in Step C), the electroplated semi-finished lead wire frame is subjected to cutting forming. The lead wire frame has a better mechanical property and a better thermoelectrical property.

Description

technical field [0001] The invention relates to the field of electronic packaging and manufacturing, in particular to a lead frame used for packaging chips, especially mainly applied to SOT (Small Outline Transistor) series lead frames. Background technique [0002] With the development of terminal electronic products in the direction of light weight and multi-functionality, it is required to have high electrical and thermal conductivity for the lead frame that carries the chip and transmits the heat and electrical signals generated by the chip. The material used for the original lead frame, especially the micro SOT series lead frame is FeNi42 alloy. The conductivity coefficient of FeNi42 alloy is 2.7%IACS, and the thermal conductivity is 10W / M.K, which can no longer meet the electrical conductivity of terminal electronic products. and thermal conductivity requirements. Another Cu-Fe-P series alloy product (C19400, C19210) has a tensile strength of 420-500MPa, which cannot ...

AI Technical Summary

Problems solved by technology

The material used for the original lead frame, especially the micro SOT series lead frame is FeNi42 alloy. The conductivity coefficient of FeNi42 alloy is 2.7%IACS, and the thermal conductivity is 10W / M.K, which can no longer meet the electrical conductivity of terminal electronic products. and thermal conductivity requirements

Another Cu-Fe-P series alloy product (C19400, C19210) has a tensile strength of 420-500MPa, which cannot meet the technical requirements of high-grade lead frames, or when some alloy materials are stamped into lead frames, due to the mechanical properties of the material (tensile strength and elongation and hardness) are low, there is a risk of fracture and deformation during the stamping process