Electron beam lithography (EBL)

EBL is a high-resolution lithographic patterning technique used to transfer intricate patterns into resists for subsequent processing. This is achieved by exposing a suitable resist to a focused beam of accelerated electrons, which polymerise or depolymerise the resist depending on its chemical composition. After exposure, the latent pattern is developed to reveal the desired structure.

UEF’s EBL system, Raith EBPG5000+ES

The device operates at 100 kV and is equipped with a high-resolution alignment microscope that supports a flexible writing method. Leveraging these capabilities, the system can expose a wide range of patterns, from simple gratings to complex geometries, in either single- or repeat-editing modes.

The system also features a substrate stage guided by laser interferometry for precise movements during exposure, enabling excellent stitching control and overlay accuracy. By combining advanced tool capabilities with our expertise, we can realise complex designs and achieve the desired critical dimensions with great accuracy.

Resist types

• Positive resists
• Negative resists

Sample holders for

• Standard wafers: 25 mm, 50 mm, 75 mm, 100 mm, and 150 mm (diameters)
• 5-inch rectangular mask
• Non—standard small piece parts.

Characteristics

• Beam:
  • 100 pA – 100 nA beam current
  • Down to 8 nm beam diameter
  • Mainfield size up to 0.56 × 0.56 mm2 variable
  • Subfield up to 7 × 7 µm2 variable
  • Addressing grid 1.25–16.125 nm variable
  • 50 MHz scan clock / 20-bit Mainfield DAC, 14-bit subfield DAC
• Resolution: < 5 nm
• Exposure area up to wafer/mask size
• Low line roughness and high pattern fidelity
• Stitching control

TAU’s EBL system, ELS BODEN, STS-Elionix

The device operates at 50 kV and can expose patterns over a relatively large area with a resolution of up to 10 nm. The tool can only scan a small area of 1 × 1 mm², because the electron optics cannot maintain beam position tolerance over a larger area. For this reason, the system is equipped with an ultra-precise moving stage that can be monitored with very high absolute accuracy by two laser interferometers.

Resist types

• Positive resists
• Negative resists

Sample holders for

• Wafers 50 mm to 200 mm
• Mask blanks 4” × 4” to 7” × 7”
• Small samples with at least one right angle (size max 50 × 50 mm2)
• More holders can be procured with extra financing (~25 k€/pcs)

Characteristics

• Beam:

• • Up to 100 nA current
  • Down to 2.0 nm beam diameter
  • Field size up to 1.5 × 1.5 mm2
  • 100 MHz scan clock / 20-bit DAC

• 210×210 mm2 exposure area
• Stitching < +/-15 nm
• Overlay < +/- 20 nm
• Mix and match lithography when combined with laser exposure or UV-lithography.

ELS BODEN, STS-Elionix