DSC500 Projection Scanner

For Panels, Substrates, displays and sensors

The DSC500 is designed to provide low cost of ownership and high process flexibility for panels up to 510 mm x 515 mm. It is tailored for today’s challenging large-area exposure applications such as displays, interconnects and flexible circuits, advanced substrates, panel-level fan-out and 450 mm wafers.

The DSC500 projection scanner combines a full-field mask, broadband projection optics with filters, a uniform scan beam, optical run-out compensation, and four selectable numerical apertures. The optical design provides a large depth of focus for fine resolution down to 3 μm L/S in thin resists, excellent trench shapes in medium thick resists and high aspect ratio vias in both thick resists and substrates with varied topography.

The DSC500 delivers CD uniformity of ±1 μm for 3 μm features. Alignment accuracy of <±1 μm is achieved by the on-axis vision system, with the additional benefit of allowing for alignment targets to be located anywhere on the substrate. The optical run-out compensation provides enhanced overlay for fan-out substrates with die-shift. Semi-automated configuration is available for R&D and pilot line production. For high-volume production, the tools offers full automation including SECS/GEM factory control.

Highlights

Large-area full-field projection imaging

No stichting - higher yields and no mask contamination

High throughput and low CoO

<3µm resolution, ≤± 1.0 µm alignment (3 sigma)

Four selectable numerical apertures, large DoF for thick resists

± 70 ppm optical magnification / die-shift compensation option

SUSS MicroTec Projection Scanner DSC500

The DSC500 performs fast, smooth and continuous serpentine scanning over the full substrate. The uniform beam, with its well-controlled projection area, helps to ensure that the features all the way out at the edges of the substrate get the same uniform dose as the inner areas. In addition, the beam overlaps itself by 50% on each scan pass to further average the dose across the entire substrate.

Prior to each scan exposure, the system measures the UV intensity and controls the stage velocity to provide the intended UV dose programmed into the recipe. The scanned light uniformity across the entire wafer is 97% (≤ 3% non-uniformity).

Features & Benefits

  • Uses easy to design full-field masks (non-inverted)
  • Best pattern and position replication
  • Superior technique for large-die and heterogeneous integration
  • No step-field size limitations – no stitching
  • Fast exposure times with good uniformity
 

The DSC500 projection scanner is equipped with a Wynne-Dyson projection lens for outstanding imaging performance. This is the same type of lens that is used by several well-known 1X UV stepper manufacturers. The DSC500 produces resolutions with <3 µm L/S.

Non-inverted imaging

Mask pattern and wafer pattern are in same orientation – easing mask design efforts. Nitrogen purging and a sacrificial window at the exit of the lens protect the valuable lens elements.

Features & Benefits

  • Enables fine resolution features with accurate CD uniformity across the entire substrate.

The beam delivery optics, including the SUSS modified Wynne-Dyson lens, are critical elements in providing the scanner’s high performance projection imaging.

The projection scanner is outfitted with a single powerful 2000W mercury arc lamp for its UV light source. The combination of the lamp and condenser optics generates > 6000 mW/cm2 initial intensity. The lamp house is also equipped with automated recipe selected diffusers to adjust intensity levels.

From the lamp house, the transmitted UV light is reflected off a cold mirror while the IR light passes through the mirror to a heat dump. The reflected UV light passes through the condenser light pipe where it is homogenized and the scan beam is shaped via an aperture. Also integrated into the condenser light pipe are auto changing wheels for four wavelength filters and four numerical apertures.

At the end of the condenser, a turning mirror reflects the homogenized UV light through the photomask and into the entrance of the Wynne-Dyson projection lens. The mask pattern is projected through the elements of the lens and exits at the bottom of the lens in the same orientation as the mask above. The non-inverted mask pattern is projected onto the substrate below as the co-mounted mask and wafer follow a serpentine scan pattern until the entire wafer has received its full-programmed dose.

Features & Benefits

  • Full-field imaging without mask contamination or stitching

The DSC500 has effective optics contamination protections built in by design. This means less optics contamination for higher yields.

Mask Contamination Protections

Mask and wafer are separated by 200 mm of vertical separation. Optional mask pellicle handling is available.

Resist Outgassing Protections

Between the sacrificial window on the lens and the wafer are approximately 8 mm of vertical separation. Constant stage motion shifting back and forth (L to R) creates airflow which helps dissipate outgassing contaminants.

The DSC500 uses a single air gauge sensor to complete 3-point level measurements across the substrate. The sensor is routinely and automatically calibrated to the same reference source to maintain high precision measurements.

Features & Benefits

  • Improved CD uniformity

 

The projection scanner calculates any needed wafer levelling adjustments from the measurement data provided by the air gauge sensors (see height measurement system). If the system determines that a levelling and/or focusing z-axis adjustment is required, then the height and tip/tilt of the z-axis stage are changed by three motors. The vertical movement of the z-stage is actively monitored and compensated for if it gets of center.

Features & Benefits

Improved focus and levelling results in improved imaging and CD uniformity.

Details: Handling

Manual substrate loading and unloading is standard for the DSC500 projection scanner. However, automatic handling is available as an option. The system handles substrate sizes up to 510 x 515mm. Each substrate is manually registered to two fixed datum points on the substrate chuck for consistent placement.

Automated Substrate Handling Option

The option includes cassette-to-cassette automatic loading and unloading via robotic handling, end-effectors and a pre-alignment station.

Automated Warped Substrate Handling

Handling for substrates with a warpage up to 2 mm bow is a standard feature. An option is available to handle substrates with up to 5 mm bow. These solutions primarily consist of the proper choice of substrate chuck and robot end-effector designs.

Features & Benefits

  • Fast, safe and reliable handling of substrates
  • Flexible for size, type and thickness

Manual mask loading and unloading is standard for the DSC500. However, automatic handling is available as an option. The size of the mask is typically 50 mm larger in each axis than the desired exposure area. The mask itself is manually registered to two fixed datum points on the mask chuck for consistent placement.

Automatic Mask Handling Option

Option includes cassette-to-cassette automatic loading and unloading via the substrate handling robot and auto end-effector exchange if necessary.

The DSC500 includes 4-selectable NA’s (numerical apertures: 0.14, 0.12, 0.10 & 0.07). The wide range of selectable NA’s enables the best balancing of resolution vs. DoF:

    • Fine resolution (i.e. 3µm) in thin resist
    • Precision structuring in medium resists
    • High aspect ratio patterning in thick resist (100-300mm)

The DSC500 comes equipped with a state-of-the-art on-axis optical alignment system capable of 2-target and 4-target global alignment. Target locations can be anywhere on the substrate.

System includes one on-axis and (through-the-lens vision) camera and a SUSS MicroTec enhanced Cognex VisionPro® pattern recognition. It ensures precise substrate alignment for high yields.

The DSC500 includes a fully interlocked safety enclosure with a clean-room compatible environment control unit (ECU). The ECU controls the temperature inside the chamber to ± 0.2° C.

Features & Benefits

  • High level of protection for the operator
  • High level of protection for the process - from the operator and environment

The projection scanner is designed for integration into a fab automation system compatible to the SECS-II/GEM interface standards. Level and details of the communication will be specified on basis of the SUSS MicroTec core software solution.

The DSC500 is available with optional, patent-pending optical compensation technology that is highly beneficial for immediate non-thermal run-in and run-out control.

Run-in and Run-out Control:

Controlling run-in and run-out errors due to mask-wafer mismatch is required in many advanced packaging applications. How it is controlled can have a significant impact on overlay and yield. Many well-known 1X projection steppers use thermal manipulation to try to control the amount of errors.

SUSS Optical Control

The DSC500’s novel optical compensation technology is immediate and accurate wafer-to-wafer magnification control. It eliminates the residual thermal lag time errors being experienced on many current lithography tools using temperature controlled chucks and reticle cooling. It therefore helps to improve overlay performance.

Features & Benefits

  • Improved run-in/run-out control compared to thermal methods
  • Overlay and yield benefits

The DSC500 is available with optional, patent-pending optical compensation technology that is highly beneficial for fan-out wafers with die-shift.

The DSC500 compensates for equivalent of both step-errors and in-shot errors. Traditional steppers only compensate for step-errors. By nearly eliminating the stepper tool’s residual in-shot systematic errors, a completely new level of fan-out wafer die-shift error reduction is achievable with the SUSS projection scanner.

SUSS magnification correction and beam steering technology is based on two highly synchronized closed-loop systems:

  1. Optical magnification zoom optics
  2. Active beam-steering

Together, these two systems apply up to ± 70 ppm of magnification correction to match the mask pattern size to the wafer pattern size. Then, as the full-field scan exposure is performed, the dual independent gimbal beam-steering system shifts the projected pattern to the shifted die position.

Features & Benefits

  • Improved fan-out wafer die-shift error mitigation
  • Overlay and yield benefits
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