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ASML PAS 5500/350C DUV Stepper

ASML PAS 5500/350c

 Precautions and Warnings

Table of content: CMI

  1. Introduction
  2. Getting Started
  3. User Manuals
  4. Links
  5. Pictures Gallery

I. Introduction CMI

The ASML PAS 5500/350C stepper is a photolithography equipment, using DUV photons (248nm) to expose DUV-sensitive photoresists through a mask, generally referred as the "reticle". In opposition to a mask-aligner, the reticle is not placed in contact or proximity of the wafer, but a projection lens (or more precisely a stack of several lenses) is inserted between the reticle and the wafer in order to reduce (standard reduction factors are 4x or 5x) the image of the reticle onto the wafer. One shot through the reticle will expose only one small part of the wafer, called the "field"; Consequently, to pattern a complete wafer, the stage will accurately step to different positions on the wafer, defined by the user, and expose the wafer in several shots.

The ASML PAS 5500/350C was first introduced in the year 2000 and was produced until 2010. It is a high throuput equipment (> 100 wafers/hour), and was used (and still is!) in major semiconductor fabs (Intel, Samsung, TSMC, etc...) producing integrated circuit (IC) chips. As time passed, more cutting-edge technologies have been introduced (scanners, immersion lithography, EUV lithography) to further push the resolution towards the nm range. DUV steppers are slowly being replaced in fabs, and are being refurbished by the original manufacturers for companies of the "More than Moore" market as well as microfabrication centers!

The ASML PAS 500/350C installed in CMi can handle 100mm (default), 150mm and 200mm (on request) SEMI standard wafers. It has options to handle transparent wafers, and can perform both topside (< 30nm accuracy) and backside alignment. The equipment resolution, defined as the finest line & space pattern that can be resolved and printed in a thin DUV photoresist is ~150nm for, but isolated resist line patterns can be printed with lower dimensions (~100nm) by overexposing.

II. Getting Started CMI


Reticles recommended for the system are the industry standard 6"x6"x0.25" quartz (ultra-low thermal-expansion) Cr blanks, although 0.15" and 0.12" thick plates can also be used. Reticles can include an additional pellicule to protect the chromium side from dust and particles contamination. The reticles (without pellicle) can be manufactured in CMi using the standard mask fabrication flow with the VPG200 and Hamatech equipment, or outsourced to your preferred mask shop such as Compugraphics, Photronics, ...

To get you started with the design of your reticle, please use the following documents:

Please note that the maximum square field size on the wafer is 2.2 * 2.2 cm2. The dimension on the reticle will be four times (4x) bigger and will fill the complete usable area of the reticle. In the case where your chips/devices are much smaller, you may be able to place several exposure fields (corresponding to different process steps) on a single reticle, as long as a >3mm Chromium band separates the fields.

In addition to your device image fields, the reticle should include ASML reticle prealignment marks (P) and reticle to wafer alignment marks (MA). It is also recommended to include a human-readable code and a barcode to identify the reticle.

The CMi Staff can assist you for the preparation of the reticle layout and the generation of the barcode.

Zero-level exposure:

To be able to reach optimal overlay accuracy (< 30nm) with the ASML stepper, it is necessary to write the zero/first level exposure (that include the ASML wafer alignment marks) on the stepper. Mix & Match with other lithography equipment (direct laser writing, Ebeam,...) is possible but the overlay accuracy specifications will not be guaranteed. Due to this, we recommend to expose the zero-layer (marks only) or first-layer (marks and 1st device layer) using the stepper.

CMi provides two reticles that contains all the alignment marks that are used with other CMi lithography equipment, as well as other designs. This includes:

This means it is not necessary for you to include any of these marks in your device fields on the reticle. Exposure jobs on the stepper can use the CMi reticles to expose the marks that are needed for your process at the coordinates of your choice.

Job edition and tool operation:

In the current phase of the ASML PAS 5500/350C installation, the tool is operated in service mode by the CMi staff. The jobs for all your alignment and exposure steps will be created and ran by the staff under your supervision. Please contact the CMi staff directly to coordinate and prepare your jobs! This section will be updated in due time.

DUV photoresists:

DUV photoresists and bottom anti-reflection coating (BARC) layers are spin-coated and developed on the Süss ACS 200 coater and developer cluster.

Currently available resists are:

More information can be found here: Photoresist Selection

III. User Manuals CMI

IV. Links CMI

V. Pictures Gallery CMI

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   JSR M108Y on BARC / "chuckspot" exposure job, 200nm resist lines and intrafield CDU measurements
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