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Substrate structure with embedded TFC (Thin Film Capacitor),

Overcoming the conventional rules of decoupling capacitors ! Overcoming the conventional rules of decoupling capacitors!

Succeeded in the production of substrates with embedded TFC (Thin Film Capacitor)

Fujitsu Interconnect Technologies Limited (FICT) has succeeded in the production of semiconductor package substrates with embedded Thin Film Capacitor (TFC). This production meets a long standing industry requirement. The embedded TFC in a substrate has larger capacitance and reduces connection inductances more than ever because it can be placed now a lot closer to the LSI as a decoupling capacitor. FICT has adopted a substrate structure technology called GigaModule-EC, which is used in this new generation substrate with TFC.
This structure meets two complex requirements; the microminiaturization of a semiconductor package and a stable power supply between the capacitor and LSIs. (This semiconductor package substrate using the GigaModule-EC structure allows you to develop a wide range of devices, from high-end products to mobile applications, allowing them to be small, energy efficient and high performing.)

Are you having a hard time meeting complex requirements of product development?

Electronic devices have been evolving quickly. While you are required to challenge the limits in developing them where future improvement seems difficult, there are more requirements for better power saving and higher performance of LSIs. A stable power supply is very important for a LSI to operate properly and efficiently. The key to this operation is where you embed a decoupling capacitor in the substrate. With the evolution of the flip-chip bonding, semiconductor packages have been getting smaller and thinner. In these circumstances, the size and the location of the capacitor on a substrate are very important, while securing enough capacitance for the operation is also a big challenge.

  • Power supply noise in high frequency range keeps our LSI from its maximum performance.
  • We want to reduce voltage drops and noise in a LSI due to operating voltage saving.
  • We want to use proper capacitors with enough capacitance to make our LSI operate properly.
  • We need capacitors with large electricity storage capacity. However, there is no space for it in our semiconductor package.


GigaModule-EC will solve all of these problems!


GigaModule-EC is a substrate structure innovation with embedded Thin Film Capacitor (TFC) for a semiconductor package substrate.(*) This technology has been developed by Fujitsu Interconnect Technologies Limited (FICT) along with Fujitsu Limited, Fujitsu Laboratories Limited, and Fujitsu advanced Technologies Limited. GigaModule-EC enables decoupling capacitors to be embedded on a substrate underneath a LSI to support high frequencies and low voltages. This technology can be used for build-up or coreless substrates, which means it can be applied to a wide range of products such as high-end, mobile and wearable devices.

GigaModule-2EC GigaModule-2EC
(Photo provided by Fujitsu Advanced Technology Limited)

* The technology used to build TFC in a substrate has been developed by FICT and Sony Semiconductor Solutions Corporation.

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The 4 challenges in manufacturing an IC package are now solved by GigaModule-EC

1. Reduce power supply noise in the high frequency range

A GigaModule-EC semiconductor package substrate contains embedded Thin Film Capacitors (TFCs) which support a LSI to operate at high frequency with low voltages. This TFC has a low impedance value in the high frequency range and it has large capacitance with low inductance.

Because this TFC in a GigaModule-EC substrate can be embedded as a decoupling capacitor underneath a LSI, the inductance between the capacitor and the LSI can be reduced. If the number of vias used in this GigaModule-EC semiconductor package substrate is increased, the inductance will be reduced even more.

Using this characteristic, the reduction of impedance in this substrate through low to high frequency range has been confirmed at a demonstration experiment. This means it is possible to reduce noise in a semiconductor package substrate at high frequency range which used to be difficult with external capacitors. Thus you can expect the frequency characteristic of a semiconductor to be greatly improved and the efficiency of the LSI maximized.

Analysis specificationThe change of impedance between V/G by embedded TFC (Data provided by Fujitsu Limited)

2. Minimize the voltage drop during operation

Since LSIs are driven with low voltage, controlling the voltage drop during the operation is getting even more challenging. However, this GigaModule-EC substrate can solve this problem. TFC which supports the high frequency range can be embedded underneath the LSIs on a substrate and this capacitor will be charged and discharged between the operations by connecting power supply layers. This enables a reduction of the power voltage instability and allows you to expect a LSI for stable high performance.

3. Have any size of capacitance for capacitor by pattern designing

This embedded TFC is a high capacitance type of 1.0μF/cm2. Because it is embedded as a shape of another layer in a substrate, the capacitance can be set for any size you need by pattern designing. This capacitor can be processed by etching. This means due to fewer restrictions at the designing stage, designs which were once considered impossible are now feasible using embedded TFC technology.

4. Use mounting space on a LSI efficiently

As we can embed the TFC into the substrate, we can dramatically reduce the number of capacitors installed on the surface of the board and consequently increase the available space. Also, because vias can be connected to TFC with a narrow pitch, there will be fewer restrictions for wiring on the substrate.


FICT's GigaModule-EC substrate which has been long-awaited in the industry brings out the maximum performance of a LSI, resulting in the improvement of the product's total performance and the reduction of its development cost.
The GigaModule-EC substrate enables to be adopted in your innovation in various fields by supporting a wide range of frequency from low to high.

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Epoch-making technology invented by the Fujitsu group and customers working together

FICT has been developing printed wiring boards and substrates to meet the requirements which other Fujitsu group companies or our customers wanted for the next generation machines. We have been supporting our customers continuously to become more competitive in their markets. With this experience and expertise, the production of the substrates with embedded TFCs has been finally obtained, though this technology was a challenge in the industry for a long time. GigaModule-EC is one of our accomplishments by following the cooperative philosophy of "working along with our customers to pursue the best solution".

It is indispensable to develop a substrate which can manage both high efficiency and low cost to survive in a radically changing business environment. A substrate is a foundation of your product. Our GigaModule-EC semiconductor package substrate with TFC embedded, and the comprehensive support of the Fujitsu group companies help you to easily incorporate innovation in your product development.

Product outline


GigaModule-2EC structure could be applied to mid-range to high-end equipment such as servers. Up to two sheets of TFC can be embedded in among core layers of the substrate which adopts regular build-up structure. It is ideal that this GigaModule-2EC structure will be used for LSI which requires a very stable power supply. Thus, it is recommended for a circuit which critically relies on a steady power supply, especially for high-speed or simultaneous switching.


  • Number of built-in TFC: 2 sets maximum
  • TFC connection via pitch: Min 300um
  • C4 bump pitch: Min 150um
  • Size: 75×75mm maximum


A cross-section of GigaModule-2EC

TFC specification


  • Capacitance: 1.0μF/cm2
  • Tanδ: 0.1 or less
  • Operating voltage: 4.0V
  • Thickness: 35μm or less (after embedded in a substrate)

A photo (left) and a cross-section (right) of TFC Provided by TDK Corporation