DSC300 Gen3 Projection Scanner

The High-Throughput Alternative to 1X Steppers

SUSS MicroTec introduces its next generation projection scanner – the DSC300 Gen3. This proprietary scanning lithography platform touts triple digit throughput with fine (< 2 μm) resolution capabilities at the lowest cost of ownership among 1X projection lithography systems.

The flexible DSC300 Gen3 Bridge-Tool for 200 mm and 300 mm wafers was re-engineered for higher performance and minimized overhead time. The DSC300 Gen3 Scanner delivers a 300 mm wafer throughput of up to 100 wph at 400 mJ/cm² and >80 wph at 1000 mJ/cm² dose. Its enhanced 1X Wynne-Dyson optics and four recipe-selectable numerical apertures (NA’s) enable the achievement of fine 2 μm features in thin resist, as well as >100 µm DoF in thick resist. The full-field imaging technology of the DSC300 Gen3 supports industry roadmaps for large die patterning and mixed die packaging for heterogeneous integration. In addition, fan-out wafer-level packaging applications can benefit from its optical die-shift compensation option. This latest die-shift and run-in/run-out mitigation feature corrects for up to ± 200 ppm (30 µm on a 300 mm diameter wafer).

With the projection scanner DSC300 Gen3, SUSS MicroTec offers a complementary technology to its mask aligner portfolio and a lowest cost of ownership alternative for traditional projection stepper lithography.

Highlights

High throughput of up to 100 wph
(400 mJ/cm² dose)

Lowest CoO among 1X projection lithography tools

Same 2 µm resolution as 1X UV stepper lithography tools

≤ 1.0 µm overlay (mean + 3 sigma)

Full-field large-die patterning without stitching

± 200 ppm optical die-shift compensation for FOWLP

The Alternative to 1X Steppers

Traditional 1X stepper lithography tools waste an excessive amount of time to ramp up stage speed, decelerate stage speed, then stop and settle. Multiply that wasted time for 50~70 shots and the resulting throughput is rather low.

Comparatively, the DSC300 Gen3 is exceptionally fast with its proprietary smooth, continuous serpentine scanning technique – no stops to waste time. The highly uniform beam with its well controlled projection area insures that the features all the way out at the edges of the wafer get the same uniform dose as the inner wafer. In addition, the beam overlaps itself by 50% on each scan pass to further average the dose across the entire wafer.

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

 

High Throughput

The DSC300 Gen3 Projection Scanner elevates 1X projection lithography throughput to new heights – achieving triple digit levels for low doses (up to 100 wph for 300 mm wafers). An additional advantage to the DSC300 Gen3 is that the high throughput is stable for a specific UV dose no matter the pattern die size or wafer layout. Further, wafer edge exposure (WEE) and wafer edge protection (WEP) are handled by the full-field mask pattern and take no additional time.

  • Drastically higher throughput compared to 1X steppers
  • Throughput is not die-size, field-size or pattern dependent
 

The DSC300 Gen3 Projection Scanner is equipped with a Wynne-Dyson projection technology lens for outstanding imaging performance. This is the same type of lens that is used by several well known 1X UV Stepper manufacturers, which is why the DSC300 Gen3 has the same imaging capabilities as these stepper litho tools (2 µm L/S in 2 µm resist).

However, the SUSS Wynne Dyson Lens is a modified and enhaced version of this well proven optics technology.

Non-inverted imaging

Mask pattern and wafer pattern are in same orientation – easing mask design efforts

DSC 300 Gen3 Enhancements

Increased the selectable "fine resolution NA" to 0.15 from 0.14. Improved prism design, coatings and closed-loop active prism cooling system for greater stability. Of course, the valuable lens elements are protected by nitrogen purging and a sacrificial window at the exit of the lens.

Features  & Benefits

Enables same imaging performance as 1X steppers, but with the much higher throughput of the projection scanner.

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

The projection scanner is equipped with a single powerful 2000W mercury arc lamp for its UV light source, which reduces consumable cost over 1X steppers that use two UV lamps. The combination of the lamp and condenser optics generate > 8000 mW/cm² initial intensity. The lamp house is also equipped with automatic 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 homogonized and the scan beam is shaped via an aperture. Also integrated into the condenser light pipe are autochanging wheels for four wavelength filters and four numerical apertures.

At the end of the condenser, a turning mirror reflects the homogonized 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 the bottom of the lens in the same orientation as the mask, above. The non-inverted mask pattern is projected onto the subtrate below as the co-mounted mask and wafer follow a serpentine scan pattern until the entire wafer has received its full programmed dose.

The projection scanner 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. In addition, vertical to horizontal HEPA airflow across workspace (front to back) sweeps particles and contaminants away from the lens.

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. In addition, vertical to horizontal HEPA airflow across workspace (front to back) sweeps particles and contaminants away from the lens.

The projection scanner is now equipped with three air gauge sensors to complete 3-point level measurements in the same time it takes for one.

In addition, the air gauge sensor design was re-engineered for state-of the-art accuracy and higher sensor longevity. Each sensor is routinely and automatically calibrated to the same reference source to maintain high precision measurements.

Features & Benefits

  • Higher throughput and lower cost of ownership

The projection scanner calculates any needed wafer levelling adjustments from the measurement data provided by three 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 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. The handling system enables safe and reliable handling of photo masks.

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 standard DSC300 Gen3 is a bridge-tool for 200 mm and 300 mm wafers. The primary tool configuration is for automatic handling of 300 mm wafers (200 mm optional). Manual load/unload option available, along with other wafer and substrate sizes.

Automated Wafer Handling (200 mm and 300 mm)

System includes a well appointed EFEM for 300 mm FOUPs with dual load ports, dual arm robot, end-effectors and pre-aligner (notch finder). For 200 mm wafer handling, either 200 mm FOUP inserts or 200 mm open cassette adapter boxes are available. Both SEMI wafers and bonded wafer pairs can be loaded.

Warped Wafer Handling

Standard and custom warped wafer solutions are available on the DSC300 Gen3 for up to 2 mm bow - standard and up to 5 mm bow - optional. These solutions primarily consist of the proper choice of wafer chuck and robot end-effector designs.

Optional Handling

Please consult factory regarding solutions for thin wafers, TAIKO wafers, smaller wafers (6”, 4”, 2”), and substrates (non-round, up to 310 x 310 mm).

Features  & Benefits

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

The DSC300 Gen3 comes equipped with a state-of-the-art, sub-micron optical alignment system capable of 2-Target and 4-Target global alignment. Target locations can be anywhere on the wafer when using 1-vision camera, but in fixed pitch locations when using the dual off-axis cameras.

300 mm Wafer Tools and 200 mm/300 mm Bridge Tools

The system includes one on-axis (through-the-lens) vision camera and two off-axis, fixed-pitch, vision cameras for simultaneous 2-Target image capturing. This ensures for fastest throughput and SUSS MicroTec enhanced Cognex VisionPro® Pattern Recognition.

Dedicated tools for ≤ 200 mm Wafers

The system includes one on-axis (through-the-lens) vision camera; one off-axis vision camera and a SUSS MicroTec enhanced Cognex VisionPro® Pattern Recognition.

Features & Benefits

Combination on-axis and off-axis alignment system with sub-micron alignment capabilities.

The projection scanner includes a fully interlocked safety enclosure with a clean-room compatible environment control unit (ECU) and novel new closed-loop, vertical to horizontal HEPA airflow system. 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 DSC300 Gen3 is available with several optional IR alignment packages for top-side and bottom-side alignment applications. These options are in addition to the optical alignment system. For IR alignment, limitations apply so a factory IR vsion test on the specific wafer material stack-up is recommended.

IR Top-Side Alignment (IR TSA) Option

The IR TSA option is used to view top-side alignment targets through opaque resist and dielectric materials. Includes one (1) top-side mounted IR Vision Camera (900-1300 nm wavelength).

IR Back-Side (Reflection) Option

Includes one top-side mounted SWIR Camera (900-1300 nm).

IR Back-Side (Transmission) Upgrade

The Transmission IR upgrade is recommended for highly dope wafers or where reflection IR did not provide adequate results. Requires purchase of option-A reflection IR (900-1300 nm). Includes one modified wafer chuck with two embedded IR diodes for back-side illumination.

Features & Benefits

Effective alignment target viewing and capturing either through opaque top-side materials or through silicon for bottom-side alignment.

Now, the DSC300 Gen 3 is available with Dual Variable NA's to boost imaging optimization to the highest level possible. This optional feature adds four selectable projection lens numerical apertures (NAp: 0.15, 0.14, 0.10 & 0.07) to the system's existing four selectable condenser numerical apertures (NAc: 0.15, 0.14, 0.10 & 0.07). The ability to mix and match the two types of NA’s enables the greatest fine tuning of their ratio to optimize sigma for the specific resist and process.

Selectable NA Combinations Enable Balancing of Fine Resolution and High DoF

  • Fine resolution (i.e. 2 µm) in thin resists
  • Precision structuring in medium resists
  • High aspect ratio patterning in thick resist (100~300 µm)

Features & Benefits

  • Greatest control over imaging performance and DoF among 1X projection lithography tools

The DSC300 Gen3 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 and how well 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 DSC300 Gen3’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; and therefore helps to improve overlay performance.

Features & Benefits

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

The DSC300 Gen3 is available with optional, patent-pending optical compensation technology that is highly beneficial for fan-out wafers with large die-shift.

SUSS Optical Compensation Option

The DSC300 Gen3 compensates for equivalent of both “Step-Errors” and “In-Shot Errors”. Traditional 1X 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 DSC300 Gen3 projection scanner.

SUSS mag 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 ± 200 ppm of magnification correction to match the mask pattern size to the wafer pattern size.

Features & Benefits

  • Improved fan-out wafer large die-shift error mitigation over 1X steppers
  • Overlay and yield benefits
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