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A method of laser welding power semiconductor chips

A power semiconductor and laser welding technology, applied in welding equipment, metal processing equipment, manufacturing tools, etc., can solve problems such as unfavorable process simplification, shorten welding time, improve production efficiency, and avoid virtual welding or chip fall off.

Active Publication Date: 2021-05-04
WUHAN LINGYUN PHOTOELECTRONICS SYST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The Chinese invention patents with publication numbers CN 104103619 B, CN 105458434 B, and CN 105914185 B all disclose the chip welding process, but they all require complex connectors on the pins or frames, which is not conducive to the simplification of the process

Method used

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  • A method of laser welding power semiconductor chips
  • A method of laser welding power semiconductor chips
  • A method of laser welding power semiconductor chips

Examples

Experimental program
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Effect test

Embodiment 1

[0045] The invention provides a method for laser welding power semiconductor chips, wherein the small power device to be welded is packaged in TO-220, and the steps are as follows:

[0046] a. Solder chip 2 and heat dissipation substrate 3

[0047] Such as image 3As shown, the first solder sheet 5 is placed between the heat dissipation substrate 3 and the chip 2, the first solder sheet 5 corresponds to the shape of the chip 2 and the chip 2 is just covered, and the first laser beam 6 is adjusted to be far away from the heat dissipation substrate 3. One side of chip 2 ( image 3 above the heat dissipation substrate 3) focus and the spot diameter on the heat dissipation substrate 3 completely covers the first solder sheet 5, and emits laser light (the first laser beam 6) to heat the heat dissipation substrate 3 for 10-15 milliseconds, so that the first solder sheet 5 Melting and welding the chip 2 and the heat dissipation substrate 3 .

[0048] b. Solder jumper 1 and chip 2 ...

Embodiment 2

[0059] In addition to the following parameters: the diameter of the second solder sheet 7 is 0.8 times the diameter of the connector 10, the spot diameter of the second laser beam 8 is 0.8 times the diameter of the connector 10, the emission time of the first laser beam 6 and the second laser beam 8 It is 12 milliseconds, and the welding method of this embodiment is the same as that of Embodiment 1.

Embodiment 3

[0061] In addition to the following parameters: the diameter of the second solder sheet 7 is 0.9 times the diameter of the connector 10, the spot diameter of the second laser beam 8 is 0.85 times the diameter of the connector 10, the emission time of the first laser beam 6 and the second laser beam 8 10 milliseconds, the welding method of this embodiment is the same as that of Embodiment 1.

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Abstract

The invention discloses a method for laser welding a power semiconductor chip, which is characterized in that the steps are: a. Welding the chip and the heat dissipation substrate, placing the first solder sheet between the heat dissipation substrate and the chip, and adjusting the first laser beam The diameter of the spot on the heat dissipation substrate completely covers the first solder sheet, and the laser is emitted to heat the heat dissipation substrate instantly; b. Weld the jumper and the chip, place the second solder sheet between the jumper and the chip, and adjust the second laser The spot diameter of the beam does not exceed the range of the jumper, and the laser is fired to heat the jumper instantly; c. Weld the jumper and the pin. Step ab of the present invention involves the welding of the front and back sides of the chip. The welding process is all low-temperature welding, which avoids the possibility of high-temperature damage to the chip, and the laser will not directly irradiate the chip, which avoids cracking or changes in electrical properties of the silicon material after local heating. question.

Description

technical field [0001] The invention relates to the technical field of laser welding, in particular to a method for welding power semiconductor wafers such as MOSFETs and IGBTs to pins and heat dissipation substrates. Background technique [0002] With the development of modern technology, semiconductor devices and components have been widely used in engineering and business. There are many packaging and welding methods for semiconductor wafer chips (referred to as chips), which can be summarized into two categories: metal alloy welding method (or called low melting point welding method) and resin pasting method. Among them, the resin pasting method is mostly used between the chip and the package, using doped metal and adhesive to form a good conductor of electricity and heat; the metal alloy welding method mainly refers to the eutectic welding of gold silicon, gold tin, gold germanium, etc., eutectic The welding method has the advantages of high mechanical strength, small ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B23K1/005
CPCB23K1/0016B23K1/0056
Inventor 林卿
Owner WUHAN LINGYUN PHOTOELECTRONICS SYST