UV-LED photolithography exposure system

idonus proposes an innovative UV illumination system based on the use of high power LEDs and highgrade microlens arrays. This product finds applications in photoresist exposure and is suitable for a wide variety of substrates. The illumination quality ensures a high homogeneity of the critical dimensions and of the side wall angles over the full surface. Indeed our design provides perfectly stable illumination conditions, i.e. highly homogeneous intensity and low divergence angles over the whole surface, thanks to a fully telecentric optics.

LED BENEFITS

Recent progresses in LED technology have rendered UV-LEDs advantageous compared with traditional mercury-based lighting:

  • Long lifespan of LEDs, meaning no more consumable required
  • No daily calibration required, instantly stable illumination
  • Limited heating, implying reduced air cooling costs
  • Low power consumption
  • Light ON only during exposure (no shutter required)
  • No maintenance costs

Custom-made illumination system can be realized according to your needs. A system can be designed to replace mercury lamps for refurbishing of old equipment.

TYPICAL PERFORMANCES

Resolution 0.5 μm
Optical power 20 to 200 mW/cm2
Exposure area 50x50 to 300x300 mm2
Optical irradiance inhomogeneity ±3%
Maximum collimation angle ±1.5° to 3°
Wavelength 365 / 385 / 405 nm
Spectrum half width 12 nm
Peak power consumption 50 to 1500 W

Optical system

Light intensity picture (80x80mm2)

Front lens of the 300x300 UV
exposure system

EXAMPLE SYSTEM SPECIFICATIONS

At idonus, our engineering team will also develop products according to your needs. In-house machining and assembling facilities shorten the time from concept to finished product.

Different possible configurations of exposure systems are shown in the next table. Different wavelengths can be mixed to get a similar illumination as mercury lamps. A system can be designed according to your needs.

System type UV-EXP100S-
100mW
UV-EXP150S-
50mW
UV-EXP200S-
30mW
UV-EXP300S-
40mW
Optical power [mW/cm2] 100 50 30 40
Exposition area [mm2] 100x100 150x150 200x200 300x300
Optical irradiance
inhomogeneity [%]
±3 ±3 ±3 ±3
Max collimation angle [°] ±2.8° ±2° ±1.5° ±2.4°
Wavelength [nm]
(single or mixed)
365 (and/or
405/435)
365 (and/or
405/435)
365 (and/or
405/435)
365 (and/or
405/435)
Spectrum half width [nm] 12 12 12 12
System size [cm] 50x30x30 50x35x35 70x40x40 90x50x50
Peak power consumption [W] 450 450 450 1400

Normalized reversed enclosed intensity

idonus UV-LED exposure system for photolithography

stand alone uv ledidonus proposes an innovative UV illumination system based on the use of high-power LEDs and high-grade microlens arrays. This product finds application in photoresist exposure and is suitable for a wide variety of substrates. Our complete line of UV illumination products addresses photolithography needs for masks and wafers up to 300 mm wide. Customized solutions can be designed to suit your specific requirements (e.g., retrofit on mask aligners, OEM for your future products).

LED BENEFITS

Until recently, mercury arc lamps were the only sources capable of providing high intensity light suitable for UV photolithography exposure. Thanks to the advances in LED technology, UV-LEDs have become a very attractive alternative to the energy-consuming mercury lamps.

Along with the ecological and security aspects, the technical advantages of UV-LEDs as compared with traditional mercury lamps are numerous and significant for photolithography. A foremost advantage of UV-LEDs is that they opeate with consistent emission for very long lifetimes. As a result, daily calibration and maintenance are not required. Furthermore, by being more energy efficient, LEDs have reduced heating, which greatly simplifies system cooling.

Benefits of UV-LED technology

  • long lifespan of LEDs, meaning no more consumable required
  • no daily calibration required, instantly stable illumination
  • instant-on, light is ON only during exposure, no mechanical shutter needed
  • low power consumption
  • limited heating, implying very low air cooling costs
  • no maintenance costs

optical systemUV-LED EXPOSURE SYSTEM

idonus has introduced a complete line of UV-LED exposure products. Our systems integrate the most effective UV-LEDs available on the market together with high-grade microlens arrays. They are fully assembled and controlled in-house. Our design features a fully telecentric optics that provides reproducible and uniform illumination conditions over the whole exposure area - i.e., highly homogeneous and stable intensity with very small divergence angles. This cutting edge optics ensures perfectly uniform exposure of the entire substrate, producing cured photoresists with straight sidewalls and enabling precise microstructuring of patterns with micrometer critical dimensions.

 

 

 

PERFORMANCES
Our UV-LED exposure system is available in several standard configurations that can be customized with a multitude of variations (e.g., single or  mixed wavelengths). As a manufacturer of special machines, idonus can also develop fully customized equipments according to client’s specifications (e.g., different exposure area, adapted equipment housing). The main characteristics of our products are given in Table 1. A typical measurement performed during the calibration process is shown in Fig. 3: In the usable exposure area, irradiance inhomogeneity is lower than ±3%. The maximum collimation angle  which is illustrated in Fig. 2 is another important parameter that we systematically characterize. Data shown in Fig. 4 are typical results extracted from measurements performed on our model UV-EXP150S-75. To evaluate , irradiance is measured as a function of the collimation angle: corresponds to the FWHM (full width at half maximum). This threshold is commonly used to consider light energy effectively contributing to photoresist irradiation. Given the performance of our exposure system, about 95% of the energy is enclosed within the collimation angle.

 

uvlight result web graph 1
Fig. 3: Irradiance inhomogeneity  Measurements show inhomogeneity lower than ±3%. Typical values extracted from our model UV-EXP100S-75 (square illumination area of 100×100 mm2).

 

Characteristics \ System type UV-EXP100S-75 UV-EXP150S-75 UV-EXP200S-45 UV-EXP300S-60
Optical power (@385nm) 75mW/cm2 75mW/cm2 45mW/cm2 60mW/cm2
Useful exposure area 100x100mm2 150x150mm2 200x200mm2 300x300mm2
Irradiance inhomogeneity ±3% ±3% ±3% ±3%
Maximum collimation angle (±α, FWHM) ±1.8° ±1.8° ±1.4° ±2.6°
External dimensions 58x23x23 cm3 58x30x30 cm3 75x40x40 cm3 90x50x50 cm3
Working distance (WD) 300mm other WD can be designed to address your specific needs
System size [cm] 50x30x30 50x35x35 70x40x40 90x50x50
Peak power consumption [W] 150 W 150 W 150 W 450 W
Wavelength (single or mixed) 365 nm and / or 385 nm / 395 nm / 405 nm
all models can be configured with UV-LEDs with multiple wavelength peaks
Table 1: Standard UV-LED exposure systems  Typical specifications of our standard products that are optimized for different exposure areas.

 

photo 1

 

photo 2

Detail view of model UV-EXP-300S-60. Anti-reflective coating gives this distintive color to the front lens. High-homogeneity 300×300 mm2 useable area exposed with model UV-EXP-300S-60.

VPE - Release service

HF vapor phase release service for MEMS

We offer a release service for MEMS wafers as well as single chips.
All the manipulations are carried out in a clean room. As every application is different we are pleased to discuss the release of your MEMS with you.

VPE - TCRC

Reaction chamber temperature control

The etch rate of silicon dioxide varies slightly with the temperature of the liquid HF in the reaction chamber. The temperature of the HF depends on the ambient temperature of the clean room. Additionally, the HF heats during long etching processes, which results in an increasing etch rate from wafer to wafer until the system has stabilized. To stabilize the etch rate we have developed a reaction chamber with temperature controlled HF in the container. The temperature of the HF can be adjusted with an additional controller. A Peltier element heats or cools the acid depending on the desired process parameters.





VPE - Publications

Publications

COMBINED AL-PROTECTION AND HF-VAPOR RELEASE PROCESS FOR ULTRATHIN SINGLE CRYSTAL SILICON CANTILEVERS
S. Mouaziz; Microsystems Laboratory, Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne, Switzerland

ETCH STOP MATERIALS FOR RELEASE BY VAPOR HF ETCHING
Thor Bakke; Fraunhofer IPMS, Dresden, Germany
16th MME Workshop 2005, Goeteborg, Sweden

QUASI-DRY RELEASE FOR MICRO ELECTRO-MECHANICAL SYSTEMS
M. Zickar; SAMLAB, Institute of Microtechnology (IMT), University of Neuchatel, Switzerland

A CLEAN WAFER-SCALE CHIP-RELEASE PROCESS WITHOUT DICING BASED ON VAPOR PHASE ETCHING
T. Overstolz; SAMLAB, Institute of Microtechnology (IMT), University of Neuchatel, Switzerland