Die Top System

Due to the continuous rise in the power density, coupled with higher operating temperatures and the demand for improved reliability, packaging materials are brought to the edge of their limits. The new Heraeus Die Top System enables the use of copper wire in combination with sinter technology. It significantly improves the electrical, thermal and reliability performance of the die connection, and effects the whole module performance. Additionally, it enables easy processing, improves the yields and helps to bring new packaging solutions faster to market.

Die Top System

Power electronic semiconductor devices are facing significant technical challenges. With the ever-growing power density, they need to be able to perform reliably on much higher temperatures than in the past, up to 200°C. In addition, higher active and passive temperature cycle capability is required. Automotive applications lifetimes with their minimum of 15 years are still relatively short compared to wind power applications (25) and traction applications, which have to last 30-40 years and longer.

In order to achieve this extreme reliability and robustness, packaging and joining technology needs to advance massively: With the attachment of copper bonding wire to the die the problem could be solved, as copper ensures a uniform thermal distribution, can endure much higher temperatures than aluminum and is by far more reliable. However, this configuration is typically difficult to process, as the die will break due to the usage of hard copper material.

With the new Heraeus Die Top System these problems can be solved. A thin copper layer in-between chip and copper wire protects the die during the wire bonding process. It enables simple processing without paste printing and complicated die fixation processes, increasing the performance and the yield. The Die Top System is a single component, which consists of a copper foil with:

  • Functional surfaces for bonding on the upper side
  • Pre-applied mAgic sinter paste and Die Fixation System on the under side

It is matched to Heraeus PowerCu Soft and CucorAl bonding wire (copper and Al-coated copper thick wire).

Heraeus has the capability to match all these materials in the Die Top System perfectly to each other. In our application center we test our adaptions directly and optimize all interfaces between the materials in order to achieve a maximum of system performance and reliability.

Save time and money with Heraeus as a qualified partner and accelerate your development process.

The Die Top System significantly improves the electrical, thermal and reliability performance of the die connection, effecting on the whole module performance. It is the only system in the world that combines a copper foil with functional surface and the die fixation system is exclusively offered to Heraeus customers.

Your benefits with the Heraeus Die Top System:

  • More than 50% increase of die current carrying capability compared to Al-wire
  • More than 10 fold increase of reliability compared to solder die attach with Al-wire
  • Less module costs for the performance rate due to higher output power at same size or die shrink at same power
  • Less hot spots by uniform temperature distribution across the die
  • Compatible for high temperature semiconductors, enables junction temperatures of e.g. 200°C
  • Very simple processing: Die Top System is designed as one single component with matched functional surfaces for sintering and bonding and with special Die Fixation System compatible with sintering and bonding
  • Simple pick and place process, it is delivered in a wafer frame as the semiconductor die itself
  • Bigger bondable area compared to other solutions
  • Less waste of silver sinter paste due to the efficient printing process
  • Cost effective due to less complexity
  • Maximum flexibility: It can be customized to any die geometry used; it can be used for moderate as well as for large volumes due to the flexible bonding wire process.

Your advantages in working with Heraeus:

  • Exactly the right solution for your application, adapted to your needs
  • Quicker time to market due to unique expertise of matching materials to systems with maximum performance and reliability
  • Capability to test all adaptations in our in-house application center
  • High innovation capabilities

The Die Top System finds practice in power inverters in:

  • Automotive - Power train H(EV)
  • Wind
  • Traction
  • Power conversion
  • Marine
  • Heavy crane
  • Other, e.g. agriculture, mining

All other applications with the aim to:

  • increase the current carrying capability of the module
  • or to reduce the module costs by shrinking the die size.

The single component Die Top System is matched to a Heraeus PowerCu Soft wire (copper thick wire) or CucorAl wire (Al-coated copper thick wire).

Bond substrate:

Core material: Cu, Cu-Alloys
Functional surfaces (optional): Ag, Au, Pd
Thickness: 30 - 500µm
Thermal conductivity: 180 – 390 W/mK
Tensile strength (Rm): 200 - 650 N/mm2
Hardness (HV): 40 - 240

Pre applied Ag-sinter layer:

Recommended sinter pressure: 10-30 MPa
Recommended sinter temperature: 230 - 280°C
Thermal conductivity: >150 W/mK
Cleaning: Not needed

Process parameters depend on customer design. We can support you to find the optimal process for your application.

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