Photolithography

This is a UV 405nm curing station primarily for the Nanoscribe 3D printed parts.

ABM's High Resolution Mask Aligner is a very versatile instrument with interchangeable light sources which allow Near-UV (405-365 nm) as well as Mid- and Deep-UV (254 nm, 220 nm) exposures in proximity (non-contact) or contact (soft & hard) modes. The exposure can cover an area 200 mm in diameter. The bottom-mount mask system accommodates masks from 4 to 9 inches square and substrates from small chips to wafers up to 200 mm. The alignment tooling system also features an air-bearing substrate-to-mask planarization system for wedge-error compensation.

This projection printer uses a DUV (248nm) lens column (0.63 N.A.) to provide a 4:1 reduction with an exposure field size up to 22mm square. Minimum feature size is <0.20µm. The number and placement of the dies is programmable. Wafer sizes of 3" up to 200mm can be accommodated, and pieces with significant effort. Registered alignment is typically <0.045µm, even when using backside alignment. 6" x 0.250"-thick quartz masks are used.

This Edge Bead Removal System uses a Brewer Science Cee Flange Spinner Model 200 platform along with a Nordson 752 Series Diaphragm Dispense Valve and their patented BackPack valve actuator controlled by their ValveMate 8000 Controller. The nozzle is mounted on a 4-axis cantilevered T-Slot arm with position micrometer on the X-axis for adjusting the bead size. It utilizes Microposit EBR 10A as a solvent.

The Gamma automated photoresist and wet processing system is designed to meet needs for clean, reliable and high throughput photolithography processing. The configuration is tailored to perform a variety of DUV photoresist and antireflection coatings, wafer baking, developing and spray coating for conformal resist wet processing tasks. The SUSS MicroTec Gamma system is equipped with two wafer cassette stations for 100mm through 200mm wafers. Different wafer sizes can be processed simultaneously without any mechanical changeover.

This projection printer uses a g-line (436nm) lens column ( 0.30 N.A.) to provide a 5:1 reduction with a variable field size up to 15mm square. Minimum feature size is <0.9µm. The number and placement of the dies is programmable. Wafer size of 3" up to 150mm can be accommodated, as well as smaller pieces. A customized hand-held chuck system allows rapid change of substrate size. Registered alignment is typically <0.25µm. 5" x 0.090"-thick masks are used.

The AutoStep 200 is a 5X reduction wafer exposure tool designed for up to 200mm wafers. All operations are automated, including wafer loading (100mm wafers) and aligning, and reticle loading and aligning (5"). Manual operation is also possible. Wafer leveling is used to provide optimum focus range. The focus system uses broadband light and is repeatable to <0.2µm. Overlay is specified as <0.125µm using local alignment. All tool calibrations are performed automatically, and the focus system is compensated for lens heating and barometric shifts. With N.A.

The CNF has a Hamatech-Steag HMP900 Mask processing system available for automatic mask developing and chrome etching. There are 4, 5, 6, and 7 inch mask chucks available. Standard mask development processes and chrome etching should be done on this tool.

The CNF has two Hamatech-Steag wafer processors for developing of wafers. Spray and puddle processes are available with wafer chucks for 3 inch, 100 mm, 150 mm, and 200 mm wafers. Chucks are also available for 4", 5", 6", and 7" Photomasks. Standard developers are available on each tool.

The CNF has two Hamatech-Steag wafer processors for developing of wafers. Spray and puddle processes are available with wafer chucks for 3 inch, 100 mm, 150 mm, and 200 mm wafers. Chucks are also available for 4", 5", 6", and 7" Photomasks. Standard developers are available on each tool.

The Heidelberg Instruments DWL 2000 is an economical, high resolution direct write pattern generator for direct writing on photosensitive Cr mask plates. The tool can handle mask sizes from 3 to 9 inches. The unit has an interchangeable write head that can accommodate different feature sizes for writing. The smallest feature size is 0.7 microns and 0.6 microns with the 4mm and 2mm write heads, respectively.

The DWL 66fs is a high-resolution imaging system for exposing Cr mask plates or wafers. The DWL 66fs will accommodate media up to 6 x 6 inches. Design data can be created with any program using DXF, HPGL, Gerber, GDSII, or CIF format and is converted into a LIC format on a “CONVERT“ workstation. Design data transfer to the system is then realized via an FTP connection.

The Jelight 144AX is a DUV exposure system used at CNF for Dicing Tape release and curing photoresist before hardbake. The gridlamp has ~30mW/cm2 output at 254nm. For resist curing, this energy will cause photoresist to crosslink at the surface, thus preventing resist flow at elevated temperatures required for hardbaking.

The NX-2500 is a multi-level nanoimprintor with imprint capabilities in thermoplastic, photo-curable and embossing. It offers excellent uniformity regardless of backside roughness of substrate and template and can correct waving and bowing of surfaces. This machine also eliminates relative lateral shifting between substrate and mold which affects mold lifetime. A very small thermal mass ensure rapid and cooling, resulting in fast process cycles.

The Nanoscribe GT2 Laser Lithography System is a two-photon polymerization (2PP) volumetric printer. It can create three-dimensional nanostructures using a NIR femtosecond laser via direct-write onto a photosensitive resin that is subjected to a non-linear two-photon absorption process. This process involves cross-linking the resin via UV absorption.

Several hot plates are available for photoresist baking.  EMS vacuum hotplates are used for typical processing, while CEE 1300X Proximity hotplates are available for DUV and critical processes.  Typical temperatures range from 90C to 205C.  Proximity gaps are programmable but are typically 160um.

The CNF has three manual resist spinners in the Photolithography preparation room. The spinners are segregated according to material compatibility.  Chucks are available for wafer sizes from 2" to 200mm, and for various size pieces.

The GYRSET System comprises a bell-shaped cover placed over the chuck and the substrate. During a spin cycle, the cover closes, creating a solvent-saturated atmosphere. All the parts involved in the GYRSET System rotate synchronously as does the confined air inside the cover. Turbulence, which can cause excessive thickness in the corners of the substrate, is thus eliminated. The photoresist coating is spread evenly over the entire surface.

The GYRSET System comprises a bell-shaped cover placed over the chuck and the substrate. During a spin cycle, the cover closes, creating a solvent-saturated atmosphere. All the parts involved in the GYRSET System rotate synchronously as does the confined air inside the cover. Turbulence, which can cause excessive thickness in the corners of the substrate, is thus eliminated. The photoresist coating is spread evenly over the entire surface.

The photolithography area has a two tank hot solvent bath for stripping photoresist. A dump rinser and double-stack spin rinse dryer make for easy stripping of wafers or photomasks.

7 hotplates are available for baking SU-8-coated substrates in the SU-8 lithography area (clean room 106).

Laminates pre-cast (dried) photosensitive polymer sheets (SUEX or ADEX) to wafers, acrylic and other substrates.

This contact aligner uses 365-436 nm light to expose wafers up to 150 mm diameter. The system features a video camera for alignment to patterns on the front or back side of the wafer. The versatile mask holder allows both round and square plates as masks, and the sample plate accommodates small and odd-shaped substrates.

The MJB4 contact aligner can be used for Topside Alignment and Backside Infrared Alignment on substrate sizes ranging 5mm square to 100mm in diameter. It is capable of printing 0.7um lines and spaces with a 365-436nm light source. This contact aligner has 5 exposure modes; Soft Contact, Hard Contact, Vacuum Contact, Soft Vacuum Contact and Gap Exposure. Alignment travel range for X and Y is +/- 5mm and 5 degrees for theta.

The YES 58-TA oven uses NH3 (ammonia) gas to reverse the tone of positive photoresist. This can be used to create an undercut profile in the photoresist for lift-off processing. In the reversal process, the chamber is purged of oxygen using vacuum and heat. It is then filled with 500 Torr of NH3 (ammonia) vapor. The NH3 reacts with the acid in the exposed resist rendering it insoluble in developer. The proceeding flood exposure causes acid to form in the previously unexposed areas allowing them to be removed in development, leaving behind the negative image of the first exposure.

The 450PB is a high temperature vacuum oven using a programmable temperature controller and programmed vacuum and nitrogen flow cycles for curing of polyimide films. The unit features filtered heated nitrogen purging from the entire surface of the roof through the floor of the chamber. This flow acts to clean the wafers during the process.

Many thanks to Yield Engineering Systems (YES) for improved controller parameters leading to better temperature control.

The YES LP-III vacuum oven is used for HMDS vapor priming. Using hexamethyldisilazane (HMDS), the unit functions as a standard vacuum vapor priming oven. Clean wafers are dehydrated through a series of heated (150C) evacuations and dry N2 (nitrogen) refills. HMDS vapor then flows into the evacuated chamber forming a monolayer on the wafer surfaces. Vapor priming is used to improve the adhesion of the photoresist to the wafer.