An IGBT module low-stress wire bonding structure
By optimizing the structural parameters and materials of the IGBT module bonding wires and combining them with a multilayer DBC backing plate, the failure problem caused by thermal fatigue of the bonding wires was solved, thus improving the reliability and lifespan of the module.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA ZHENHUA GRP YONGGUANG ELECTRONICS CO LTD STATE OWNED NO 873 FACTORY
- Filing Date
- 2026-04-24
- Publication Date
- 2026-07-31
AI Technical Summary
During the packaging process of IGBT modules, the failure rate due to thermal fatigue of bonding wires accounts for a high proportion, and existing technologies lack research on key structural parameters to improve lifespan.
Optimize the structural parameters of the bonding wire, including vertex spacing, joint length, height, wire diameter and angle, and use aluminum or copper bonding wire, combined with a multilayer DBC backing plate, to optimize thermal stress concentration and plastic strain accumulation.
It significantly improves the power cycle reliability life of IGBT modules, reduces the number of bond wire failures, and increases lifespan by approximately 20%.
Smart Images
Figure CN122497404A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor power device packaging technology. Background Technology
[0002] The reliability and lifespan of IGBT modules are receiving increasing attention. Among failures caused by packaging, bonding wire failure accounts for nearly 50%. Under thermal fatigue conditions, thermal mismatch occurs between the bonding wire and each layer of the package due to the difference in the coefficients of thermal expansion of the materials. This causes the root of the bonding wire to be subjected to alternating stress. When the stress exceeds the yield strength of the material, it will cause the accumulation of plastic deformation, which will then lead to crack initiation and gradual propagation, resulting in bonding wire failure.
[0003] Therefore, optimizing the morphology of the bonding wire tip and the lead shape parameters can improve bonding reliability, but the impact of key structural parameters on actual lifetime is still poorly studied. Summary of the Invention
[0004] To address the aforementioned technical problems, this invention provides a low-stress bonding wire structure for an IGBT module, comprising bonding wires bonded to the IGBT chip. The vertex spacing of the bonding wires is 1.4 mm to 1.8 mm, the connector length is 0.4 mm to 0.6 mm, the height is 1.0 mm to 1.4 mm, the wire diameter is 0.35 mm to 0.40 mm, and the angle is 12° to 18°. The vertex spacing is the horizontal distance between the highest point of the bonding wire and the bonding point on the IGBT chip; the connector length is the length of the bonding wire bonded on the IGBT chip; the height is the vertical distance between the highest point of the bonding wire and the surface of the IGBT chip; the wire diameter is the diameter of the bonding wire after bonding; and the angle is the angle formed between the bonding wire after bonding and the surface of the IGBT chip.
[0005] The vertex spacing is 1.6 mm.
[0006] The connector is 0.5 mm long.
[0007] The height is 1.2 mm.
[0008] The wire diameter is 0.38 mm.
[0009] The angle is 15°.
[0010] The bonding wire is made of aluminum or copper.
[0011] It also includes a DBC substrate, on which the IGBT chip is mounted. The DBC substrate is a stacked DBC substrate.
[0012] Compared with the prior art, this invention effectively improves the power cycle reliability life of IGBT modules by optimizing the thermal stress concentration and plastic strain accumulation at the root of the bonding wire. It is suitable for IGBT full-bridge modules with stacked DBC packages and can be widely used in the manufacturing of IGBT power modules in new energy vehicles, smart grids, rail transit and other fields.
[0013] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description
[0014] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.
[0015] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the internal DBC liner structure of the 1200V / 35A IGBT module in this embodiment; Figure 3 This is a graph showing the power cycle test life verification results of this invention.
[0016] In the diagram: 1-vertex spacing, 2-joint length, 3-height, 4-wire diameter, 5-angle. Detailed Implementation
[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the embodiments of this invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details are presented in the embodiments of this invention to facilitate a better understanding of this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments. The division of the following embodiments is for ease of description and should not constitute any limitation on the specific implementation of this invention. The embodiments can be combined with and referenced by each other without contradiction.
[0018] Example 1 like Figure 1The diagram illustrates a low-stress bonding wire structure for an IGBT module, comprising bonding wires bonded to the IGBT chip. The vertex spacing 1 of the bonding wires is 1.4 mm to 1.8 mm, the connector length 2 is 0.4 mm to 0.6 mm, the height 3 is 1.0 mm to 1.4 mm, the wire diameter 4 is 0.35 mm to 0.40 mm, and the angle 5 is 12° to 18°. The vertex spacing 1 is the horizontal distance between the highest point of the bonding wire and the bonding point on the IGBT chip; the connector length 2 is the length of the bonding wire bonded on the IGBT chip; the height 3 is the vertical distance between the highest point of the bonding wire and the surface of the IGBT chip; the wire diameter 4 is the diameter of the bonding wire after bonding; and the angle 5 is the angle formed between the bonding wire after bonding and the surface of the IGBT chip.
[0019] The vertex spacing is 1.6 mm.
[0020] The length 2 of the connector is 0.5 mm.
[0021] The height 3 is 1.2 mm.
[0022] The wire diameter 4 is 0.38 mm.
[0023] The angle 5 is 15°.
[0024] The bonding wire is made of aluminum or copper.
[0025] like Figure 2 As shown, it also includes a DBC substrate, on which the IGBT chip is mounted. The DBC substrate is a stacked DBC substrate.
[0026] Example 2 The power cycling test verifies the following: A power cycling comparison test was conducted on a 1200V / 35A IGBT full-bridge module to verify the effectiveness of the parameters. The parameter group of this invention was selected as the optimization group, and any parameter group was selected as the control group. (1) Test conditions: The test system was built in accordance with the industry standard for reliability testing of power devices. After the device was uniformly coated with thermal grease, it was fixed to the water-cooled heat sink with standard torque to ensure that the heat dissipation conditions of the two groups of samples were consistent. The constant current loading mode was adopted, with a loading current of 24A, a chip junction temperature fluctuation range of 50℃~150℃, ΔT=100℃, a turn-on time of 3s, and a turn-off time of 5s to simulate the high-frequency switching conditions of the actual application of IGBT modules.
[0027] (2) Testing and termination criteria: A small current of 100mA is applied during the device turn-off phase. The on-state voltage drop (Vceon) data is collected in real time through a high-precision electrical parameter detection system. The voltage drop data is converted into a junction temperature curve using the temperature-sensitive coefficient method to achieve dual monitoring of temperature and electrical parameters. The abnormal change in Vceon caused by the complete detachment of the bonding wire is used as the test termination criterion to define the power cycle life of the module.
[0028] (3) Test results: The power cycle life of the control group was 52,000 cycles, and the on-state voltage drop curve showed three obvious step-like jumps, corresponding to the sequential detachment of the three bond lines; the power cycle life of the optimized group increased to 62,000 cycles, which is about 20% higher than that of the control group. Figure 3 As shown.
[0029] Those skilled in the art will understand that the above embodiments can be modified in form and detail in practical applications without departing from the spirit and scope of the invention.
Claims
1. A low-stress bonding wire structure for an IGBT module, characterized in that: This includes bonding wires bonded to the IGBT chip, with a vertex spacing (1) of 1.4 mm to 1.8 mm, a connector length (2) of 0.4 mm to 0.6 mm, a height (3) of 1.0 mm to 1.4 mm, a wire diameter (4) of 0.35 mm to 0.40 mm, and an angle (5) of 12° to 18°; among which, The vertex spacing (1) is the horizontal distance between the highest point of the bonding wire and the bonding point on the IGBT chip, the connector length (2) is the length of the bonding wire bonded on the IGBT chip, the height (3) is the vertical distance between the highest point of the bonding wire and the surface of the IGBT chip, the wire diameter (4) is the diameter of the bonding wire after bonding, and the angle (5) is the angle formed between the bonding wire and the surface of the IGBT chip after bonding.
2. The low-stress bonding wire structure of the IGBT module as described in claim 1, characterized in that: The vertex spacing (1) is 1.6 mm.
3. The low-stress bonding wire structure of the IGBT module as described in claim 1, characterized in that: The length (2) of the connector is 0.5 mm.
4. The low-stress bonding wire structure of the IGBT module as described in claim 1, characterized in that: The height (3) is 1.2 mm.
5. The low-stress bonding wire structure of the IGBT module as described in claim 1, characterized in that: The wire diameter (4) is 0.38 mm.
6. The low-stress bonding wire structure of the IGBT module as described in claim 1, characterized in that: The angle (5) is 15°.
7. The low-stress bonding wire structure of the IGBT module as described in claim 1, characterized in that: The bonding wire is made of aluminum or copper.
8. The low-stress bonding wire structure of the IGBT module as described in claim 1, characterized in that: It also includes a DBC substrate, on which the IGBT chip is mounted. The DBC substrate is a stacked DBC substrate.