infineon AN2006-02 Apply Thermal Grease in IGBT Modules User Manual
- June 3, 2024
- infineon
Table of Contents
infineon AN2006-02 Apply Thermal Grease in IGBT Modules
About this document
Scope and purpose
This application note provides a guideline on how to apply thermal grease or
paste on IGBT power modules using a stencil.
Intended audience
This document is intended for all technical experts using Infineon power
modules in various applications.
Introduction
While operating semiconductor modules, power losses need to be transferred to a heat sink, so that the maximum junction temperature of the components is not exceeded. A thermal compound is normally used to reinforce thermal contact between the module and the heat sink, thus compensating a potential unevenness or surface roughness of the heat sink or the baseplate. The screen-printing process for applying thermal compounds is described in the subsequent chapters.
Screen-printing template
In contrast to conventional paste-application methods, the screen-printing
procedure applies the thermal compound only to areas where it is required. For
this process, a surface scan of the baseplate is used to determine the
quantity of thermal compound required. Figure 1 shows the baseplate surface
structure of a mounted EconoPACK™ 3 module.
Surface of a mounted EconoPACK™ 3 baseplate
The blue or violet lines represent the metallic contact with the heat sink,
and the red lines indicate areas that do not show thermal contact with the
heat sink. The cavities in the baseplate have to be filled with thermal
compounds. To determine the required paste, divide the surface scan into a
grid. For each grid point, a sufficient amount of paste has to be determined.
Figure 2 shows the screen-printing template of an EconoPACK™ 3 with three DCBs
from this procedure.
Screen-printing template for an EconoPACK™ 3 baseplate
Note:
Corresponding drawings for different module types are available in CAD format
and can be ordered through your sales partner.
Application of thermal compound
An example of the process of screen printing for applying thermal compound to an EconoPACK™ 3 module is shown below.
The following items are required to perform this process:
- Isopropyl or ethylene alcohol
- Putty knife
Steps
-
Clean the dirt and residue from the heat sink and template by using isopropyl or ethylene alcohol according to Figure 3.
Cleaning the screen-printing template -
To align the template and module, insert the module into the corresponding holding fixture and hold it in position. Next, align the baseplate, on which the thermal compound is to be applied, upwards, and place the corresponding template on it. The holding fixture is shown in Figure 4.
Application of thermal compound
Alignment of the module -
Apply the paste into the holes of the template with a putty knife. Figure 5 shows an example of this procedure.
Paste spreading -
Remove the template carefully from the baseplate according to the following Figure 6.
Removing the screen-printing template -
The resulting print image of the thermal compound on the module baseplate is shown in Figure 7.
Advantages of the screen-printing process
Compared to conventional methods of paste application, the screen-printing process ensures that:
- the thermal compound is only applied to areas where it is required
- the application is reproducible
- better thermal coupling is achieved
Figure 8 and Figure 9 show images of paste application done by screen printing
and by roller, respectively.
Applied with a template
Applied with a roller
In the above figure, the areas marked with a red circle show excess thermal paste and a rough structure. The images demonstrate clearly that the screen- printing application ensures an optimum distribution and structure of the thermal paste.
Attention:
For penetration levels lower than 370 as per DIN ISO 2137, it is recommended
to check the print image of a module or heat sink in cold and warm conditions.
Revision history
| Document version | Date of release | Description of changes |
|---|---|---|
| V0.2 | 2005-12 | Initial version |
| V1.10 | 2021-12 | Current state of the technology + update of format and some |
figures
Edition 2021-12-10
Published by
Infineon Technologies AG
81726 Munich, Germany
© 2021 Infineon Technologies AG All Rights Reserved.
Do you have a question about any aspect of this document?
Email: erratum@infineon.com
Document reference
IFX-jbh1635260531612.
IMPORTANT NOTICE
The information contained in this application note is given as a hint for the
implementation of the product only and shall in no event be regarded as a
description or warranty of a certain functionality, condition or quality of
the product. Before implementation of the product, the recipient of this
application note must verify any function and other technical information
given herein in the real application. Infineon Technologies hereby disclaims
any and all warranties and liabilities of any kind (including without
limitation warranties of non-infringement of intellectual property rights of
any third party) with respect to any and all information given in this
application note.
The data contained in this document is exclusively intended for technically trained staff. It is the responsibility of customer’s technical departments to evaluate the suitability of the product for the intended application and the completeness of the product information given in this document with respect to such application.
WARNINGS
Due to technical requirements products may contain dangerous substances. For
information on the types in question please contact your nearest Infineon
Technologies office.
Except as otherwise explicitly approved by Infineon Technologies in a written
document signed by authorized representatives of Infineon Technologies,
Infineon Technologies’ products may not be used in any applications where a
failure of the product or any consequences of the use thereof can reasonably
be expected to result in personal injury.
Read User Manual Online (PDF format)
Read User Manual Online (PDF format) >>