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  • By: Graphene Flagship
  • Graphene Flagship
  • Publishing date: 25 April 2023
  • By: Graphene Flagship
  • Graphene Flagship
  • Publishing date: 25 April 2023

2D-EPL MPW run in production

A step-by-step look at the 2D-EPL’s first multi-project wafer run

The 2D Experimental Pilot Line (2D-EPL) is a Graphene Flagship project created to address the challenges of establishing reliable fabrication processes for high-volume production of graphene and related materials (GRM) based electronics, photonics and sensors. Part of this process is the development of multi-project wafer (MPW) runs in which customer designs are included as dies on joint wafers. This article will take us through the manufacturing steps involved in the 2D-EPL’s first MPW run. Future runs will operate in a similar fashion, though they will be tailored to different applications and build on the experience of past runs.

STEP 1: BACK GATE AND CONTACTS

The fabrication process includes several metallisation steps to deposit the back gate as well as the bottom and the top contacts. Each metallisation step is formed by four sub-steps (coating, UV contact lithography, development, metal evaporation, and lift-off).

Step 1

UV contact lithography
UV contact lithography
UV contact lithography
Wafer coating & development
Wafer coating & development
Wafer coating & development

STEP 2: DIELECTRIC DEPOSITION

The gate dielectric (Al2O3-layer) is deposited using atomic layer deposition (ALD).

Step 2

ALD tool
The gate dielectric (Al2O3-layer) is deposited using atomic layer deposition (ALD).
The gate dielectric (Al2O3-layer) is deposited using atomic layer deposition (ALD).

STEP 3: GRAPHENE TRANSFER AND PATTERNING OF GRAPHENE

The graphene is grown by Graphenea (Spain), who then transfer it onto the wafer. After the transfer, the wafers are sent back to AMO where it is patterned in the desired shape using reactive ion etching and plasma etching.

Step 3

Plasma etching
Plasma etching
Plasma etching

STEP 4: CONTACTS AND ENCAPSULATION

After graphene is patterned, the wafers undergo a final metallisation step when the top contacts are fabricated, followed by encapsulation with Al2O3.

Step 4

wafers undergo a final metallisation step when the top contacts are fabricated

STEP 5: OPENING OF ENCAPSULATION

For encapsulation, the wafer goes through another round of coating, lithography, development, evaporation and lift-off to open the contact pads and the graphene area of the sensors.

Step 5

the wafer goes through another round of coating
another round of coating, lithography, development, evaporation and lift-off
lift-off
lifting the wafer off

STEP 6: TESTING

Finally, the wafers are extensively tested using optical microscopy, Raman spectroscopy, as well as electrical measurements on test devices.

Step 6

wafers are extensively tested
electrical measurements
electrical measurements close-up
AFM test
AMO 2D-EPL wafer production team

AMO team celebrates a job well done!

Banner ad, apply to the 3rd 2D-EPL MPW run

Apply today to take part in the 2D-EPL's third MPW run, to be delivered by AMO for electronics or sensor applications.

Author bio


Graphene Flagship
Graphene Flagship

The Graphene Flagship is a Future and Emerging Technology Flagship by the European Commission. With a budget of €1 billion, the Graphene Flagship represents a new form of joint, coordinated research on an unprecedented scale, forming Europe's biggest ever research initiative.