Lead welding technique for packaging semiconductor power device

Abstract

The invention discloses a lead welding technique for packaging a semiconductor power device and belongs to the technical field of semiconductor power device packaging and manufacturing. According to the technique, lead connection is achieved through a brazing technique, and the brazing process is achieved through lasers, wherein lead connection refers to the completion of the welding process of a lead and a chip and the welding process of the lead and two welding points of a frame. In the welding process, the lead, the frame and a chip welding pad are preheated through direct laser spot radiation, the diameter of laser spots is 1 mm, and laser radiation time is 10 ms; and a brazing wire is heated through direct laser spot radiation, the diameter of the laser spots is 1 mm, and laser radiation time is 10 ms. By the adoption of the technique, the wet aluminum pad and the frame can be melted directly to achieve stable and reliable connection of the lead, the chip and the frame, the aluminum pad and the frame cannot be melted due to the fact that the temperature does not reach the melting point, and the aluminum pad and the frame are just preheated, so that the surfaces are stretched fully to assist in combination of the aluminum pad and liquid brazing filler metal and combination of the frame and the liquid brazing filler metal, and therefore mechanical damage, thermal damage and the stress problem existing in a traditional routing technique are avoided.

Description

technical field [0001] The invention relates to the technical field of semiconductor power device packaging and manufacturing, in particular to a wire welding process for semiconductor power device packaging. Background technique [0002] In nature, the electrical conductivity and thermal conductivity of copper are second only to silver, and the affinity between copper and humans is second only to titanium. Therefore, copper has been widely used in the fields of electricity transmission, heat exchange and daily necessities. Applications. [0003] In the packaging and manufacturing process of semiconductor power devices, considering the characteristics of high current, high calorific value and ultra-high power of power devices, it is decided to use copper instead of or partially replace aluminum wires to complete the connection between chips and pins, and the most critical link , that is to realize the stable connection between the copper wire (copper wire or strip-shaped co...

AI Technical Summary

Problems solved by technology

[0011] 1. Due to technical defects, thick copper wires cannot be bonded, making copper, which has better electrical and thermal conductivity than aluminum, unable to be used in high-power semiconductor devices

[0012] 2. The bonding process requires a large force to act on the surface of the chip, which can easily lead to microcracks inside the device chip, greatly reducing the reliability of the device, especially in automobiles, electric locomotives, and high-voltage transmission and transformation circuits.

[0013] 3. Thick aluminum wire bonding machine is too cost-effective

If this point is ignored, many problems will be caused, such as warping caused by thermal stress, continuous diffusion caused by higher than the diffusion temperature, making the diffusion depth exceed the product setting value, etc.

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