Manual UV Curing System U-300

Reliable and precise UV-curing station used to reduce the adhesion force of UV tape/film on wafers or frames up to  Ø400mm. 

  • Uses 72 high powered LEDs operating in the UVA band (365nm wavelength)
  • Energy dosage range of 145 - 1520 mJ/cm2, homogeneity of dosage is +/- 10%
  • Built-in interface for a Nitrogen purge directly above the curing area (optional)
  • Motorized conveyor moves the wafer across the LED array for a uniform exposure
  • No warm-up time needed and no ozone or dangerous mercury gas generated

Dose: 145 - 1520 mJ/cm²
Wafer Size: up to Ø300mm (without frame) / up to Ø400mm (with frame)
Frame: up to Ø400mm DTF 2-12 and DTF 2-12-1
Substrate thickness: max 5mm, larger thicknesses possible
Minimum substrate diameter: Ø8" standard, smaller substrates also possible
Throughput: up to 200 UPH
Width: 994mm
Depth: 515mm
Height: 173mm
Weight: 25 kg
Conveyor speed: 4.7 mm/s - 42.5 mm/s
Number of LED: 72 (9 strips of each 8 LED)
Peak Wavelength: 365nm +/- 3nm
Radiant flux per LED: 750mW
Homogeneity of dose: +/- 10%
Nitrogen pressure: 3 bar
Nitrogen connector: outer diameter Ø 6mm
Main Power: 100-240 VAC, 50/60 Hz
Certification: CE Certified, IEC 204-1 safety standards

 

The U-300 UV-LED exposer is a very efficient solution for exposing UV film. Usually, this step takes place after the separation of the wafer to reduce the adhesion force when picking the die. The use of this curing device ranges from creating development samples in R&D departments, start-ups, or universities to series production in large companies for a throughput of up to 200 wafers per hour. This device can be used to expose commercially available UV films of the leading manufacturers, with an average wavelength of 365nm exclusively in the UVA range.

By using LEDs instead of traditional means, there are numerous advantages that are gained including longer lifetime, lower maintenance costs, no warm-up time, and no ozone gas or dangerous mercury gas generation. In contrast to common mercury vapor lamp systems, this device does not require a long warm-up time and is ready for use immediately upon being turned on. Also, with the use of our potentiometer, the conveyor speed and thus the exposure time can be precisely adjusted according to the specification of the UV film. With the U-300 and its 72 high powered LEDs, an adjustable dose between 145 and 1520 mJ/cm2 per working cycle can be achieved. Higher doses can be achieved by exposing the substrate a second time immediately after the first pass.

Very short set-up times, low operating costs, small footprint, and the high quality end results have made the U-series from Powatec a product that has been in great demand internationally in cleanroom applications for 15 years.

Process Overview


Manually place the mounted wafer and frame onto the conveyor with the wafer side facing up, this will allow the adhesive tape to be fully exposed by the UV-LED array. The UV light dose required for your specific tape can be easily adjusted on the potentiometer by setting it to the corresponding conveyor speed; lower conveyor speeds result in higher doses and vice versa. Once the substrate has fully traversed the LED array, it can then be manually removed for further processing (e.g., die picking). A pre-installed limit switch detects when the frame or substrate is near the end of the conveyor and automatically turn it off. The blue glass shield offers enough protection against UV light for one to safely operate the U-300 with the cover open. Nevertheless, if specific customer safety requirements dictate the cover must be closed during UV cycling, this device is equipped with a cover switch that can be activated to only operate when the cover is closed, and to switch off the LEDs if the cover is opened.

Nitrogen Option


The U-300 can be equipped with a nitrogen purge option located above the LED array, which will improve the chemical reaction of the process by reducing the concentration of oxygen in UV exposure area. A nitrogen purge is a common application in the industry when curing UV tape, especially when operating with mercury gas lamp systems to neutralize ozone. Although the LEDs used in the U-300 do not emit ozone during the curing process, the nitrogen purge option is still recommended especially when working with small dies (5mm x 5mm or smaller) to ensure a higher quality result. The reason is that in the area of contact between the UV tape and the wafer (along the border of the wafer/dicing lanes), the adhesion layer of the UV tape tends to be less reactive when exposed to air (oxygen) and adhesive residuals can remain on the die. These adhesive residuals on small dies or very sensitive wafers can result in an unsuccessful picking operation.

The nitrogen purge option comes integrated into a specialized UV protection shield and additional components in the U-300 housing ensure an even distribution of nitrogen over the surface area of the LED array.

Calibration Option


The UV Integrator is a calibration tool used to measure the intensity of the LEDs over time. This tool provides a relative comparison of intensity over time to ensure the correction of the conveyor speed setting table, so it is worth noting this measurement method does not allow absolute measurements. The disc-shaped measuring device is optimized for the application of the U-300 by placing it on the conveyor like a wafer. During the exposure process, the intensity is integrated and displayed in radiant flux of mJ/cm2.

Options


Nitrogen Purge

Used to improve the chemical reaction of the process by reducing the concentration of oxygen in UV exposure area. Recommended for applications with dies smaller than 5mm x 5mm.

UV Integrator

This calibration tool provides a relative comparison of intensity over time to ensure the correction of the conveyor speed setting table.

Safety Bridges for Small Substrates (<6")

Required to ensure that substrates less than 6" in diameter do not touch the sensitive LEDs during the curing process.

Distance Plates

Required to allow substrates thicker than 5mm or grip rings traverse the LED array.

U-300 with LCD Touch Screen

  • 3.8" LCD touch Screen
  • PIN protection
  • 10 favorite UV curing programs storable
  • cycle counter and total operating time
  • idle time setting

FAQs


How is the dosage (mJ/cm2) controlled?
By varying the conveying speed over the LED array. The LEDs keep a constant radiant flux.

I must apply at least twice the dose compared to the data sheet of the UV tape manufacturer. Why?
This is not unusual. The U-300 is calibrated with our UV Integrator at POWATEC which is also periodically calibrated. It is important to understand that different UV-Integrators on the market have a significant variance (up to lower digit factors). This means that absolute comparison with the necessary dose declared on the UV tape datasheet by the manufacturer does not necessarily need to match with the table. Many factors can lead to deviations such as:

  • Mercury gas lamp spectrum vs. LED spectrum
  • Reflections by the wafer/substrate
  • Temperature
  • Deviation in homogeneity
  • UV calibration source of the UV tape supplier vs. UV-Integrator tools

Instead, POWATEC recommends to empirically evaluate the results with different conveying speeds for each combination of tape and wafer/substrate. Together with the optionally available UV-Integrator by POWATEC, it is then possible to ensure continuous constant process conditions and repetitive results. It is not recommended to rely on an absolute value.

What is the maximum thickness of the wafer/substrate?
5mm, in the standard configuration. Larger thicknesses can be processed with additional distance plates.

Can I process UV tape on grip rings instead of frames?
YES, with optionally available distance plates between the blue protection glass cover

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