Packaging structure of multi-chip wide bandgap power module based on conductive metal clip interconnection

Abstract

The invention discloses a multi-chip wide bandgap power module packaging structure based on the interconnection of conductive metal clips, including power substrates, conductive metal clips, power terminals, drive terminals and electronic power semiconductor chips, suitable for multiple wide High-current level power modules with band-gap semiconductor power chips connected in parallel. A number of series or parallel power electronic power semiconductor chips are arranged on the conductive metal substrate on the upper surface of the power substrate; in the power circuit, a conductive metal clip is used to replace the traditional aluminum bonding wire to complete the electrical connection of the power circuit in the power module; the conductive metal The layout design of the clip greatly improves the distribution uniformity of the parasitic inductance of the parallel branch in the power module, achieving the effect of parallel chip current sharing; the same spacing between adjacent chips ensures that the heat dissipation conditions are almost the same, achieving the effect of chip temperature uniformity; The shape design of the conductive metal clip connector reduces the thermal-mechanical stress generated by the work and improves the reliability of the power module; the heat transfer capability of the conductive metal clip enables the power module to achieve a double-sided heat dissipation structure.

Description

technical field [0001] The invention belongs to the technical field of semiconductor packaging, and in particular relates to a multi-chip wide bandgap power module packaging structure based on conductive metal clip interconnection. Background technique [0002] The power module is a module formed by packaging and integrating a series of power electronic power chips according to certain functions. Compared with the power electronic converter composed of discrete power electronic power devices, the power module has high reliability and high integration It has high advantages in electrical performance, thermal performance, safety protection, cost and so on. [0003] In recent years, with the continuous development of power electronic devices, the continuous improvement of application environment requirements in important fields such as oil drilling, electric vehicles, shipboard systems, and aerospace, and the introduction of energy-saving slogans, power modules are moving to sm...

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Problems solved by technology

[0005] 2. Traditional power modules mostly use aluminum bonding wires as the interconnection method in electrical connection, which is characterized by one-sided heat transfer. This heat dissipation method is called single-sided heat dissipation, and the heat dissipation efficiency is low. High resistance, which is very unfavorable for the use of power modules in harsh environments; aluminum bonding wires are prone to aging or even falling off at the bonding points under high temperature applications, resulting in failure of power modules, which is not conducive to the application of power modules in extreme environments; The flow area of ​​the aluminum bonding wire is small, and the current passing through one bonding wire is limited. In the power module that needs to pass a large current, more than 20 bonding wires need to be used, which makes the power module The process is complicated, and the volume of the power module is also increased due to insufficient space utilization;

[0006] 3. It is difficult for traditional power modules to achieve chip current sharing and temperature sharing, which is crucial in high operating frequency and harsh environments

The uneven dynamic current of the chip is mainly due to the uneven distribution of the parasitic inductance of the parallel branch of the chip. The uneven distribution of the parasitic inductance will cause the power chip to be subjected to unequal current and voltage stress during the switching transient, and the breakdown of the power chip is very likely to occur. Ineffectiveness, which has a more obvious impact on wide-bandgap semiconductor power devices; at the same time, uneven dynamic current can cause uneven chip loss, which in turn makes chip temperature uneven, resulting in aging and failure of the bonding layer of different chips The rate is different, and by affecting the threshold voltage of the chip, it will aggravate the dynamic current unevenness of the parallel chip, and further accelerate the failure of the power module as a whole

[0007] Some companies use copper sheets instead of traditional bonded aluminum wires to complete the interconnection of power semiconductors, but the shape of the connection parts has not been specially designed, resulting in greater stress on the copper sheets and solder layers under working conditions, reducing power The service life of the module; in addition, this method is currently only used for the connection of single-power chips, which cannot meet the requirements of high-power and high-current applications.

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