Phase Change Material Short Specification, Revision 1.2 Short Specification Phase Change Paste Pre-applied thermal interface material Revision 1.2 Phase Change Material Short Specification, Revision 1.2 Introduction There are a lot of advantages in using phase change thermal interface material for enhancing the thermal conduction between module and heat sink. There is no risk of smearing during transportation or assembly as the material is solid at room temperature. The applied screen-printing process is very accurate. Therefore the thickness of the material is well defined and the heat transfer capability can be optimized to a maximum. As the phase change material is solid at room temperature, the workers do not have to handle it with special care at the assembly. When the material is heated during the soldering process, it is becoming soft but don’t flow. Surface has to be protected only if something can touch the surface of the module during or directly after the soldering process (e.g. a carpet of the soldering oven). Figure 3 shows an example for such a spacer. After the soldering, the heat sink can be mounted. There is no difference to the standard mounting process, described in the housing specification. If the heat sink is mounted, the module should be heated up (e.g. during the burn-in test of the system). If the surface temperature of the module exceeds 45°C, the phase change material melts fills the gaps and provides an optimal thermal connection between module and heat sink. Features • • • • • • • • Faster and easier assembly of the module Optimized thickness of the thermal conducting material Better Rth and reduced risk of DCB crack Easier production process, no need of screen printing facilities Highest process reliability because of automated screen printing No risk of smearing of the thermal paste, material is solid at room temperature Standard solder profile applicable (e.g. J-STD-001, J-STD-003) Compatible with Press-fit pins Phase Change Material Short Specification, Revision 1.2 Physical Properties Parameter Thermal Conductivity Phase Change Temperature Value 3.4 +45 Unit W/m*K °C Mechanical Dimensions Parameter Thickness flow 0 Thickness flow 1 Thickness flow 1B Diameter of Pattern (D1, see Figure 1) Distance between Pattern (D2, see Figure 2) Value Min. 30 40 70 Unit Typ. 55 60 90 3.46 0.5 Max. 80 80 110 μm μm mm mm Reliabilty Tests Test High Temperature Storage High Humidity and High Temperature Temperature Cycling Figure1: Pattern dimensions Conditions 2 x 500h @ 85°C 2 x 500h @ 85% RH and 85°C 100 x (30m @ 125°C / 30m @ -40°C) Figure 2: Measurement points for material thickness Figure 3: Example for a surface protection spacer Phase Change Material Short Specification, Revision 1.2 DISCLAIMER: The information given in this document does not represent assured characteristics. For tested values please contact Vincotech. Vincotech reserves the right to make changes without further notice. Vincotech does not assume any liability arising out of the application or use of any product or circuit described herein; neither does it convey any license under its patent rights, nor the rights of others. LIFE SUPPORT POLICY Vincotech products are not authorised for use as critical components in life support devices or systems without the express written approval of Vincotech. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, or (c) whose failure to perform when properly used in accordance with instructions for use provided in labelling can be reasonably expected to result in significant injury to the user. 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness.