What is Soft Lithography?

university wafer substrates

Soft Lithography Used To Study Bacterial Navigation

An associate research scientist requested a quote for the following:

Can you choose a wafers for our research? We use the wafers to make molds for PDMS microfluidic devices by soft lithography, and the devices are used for studying bacterial navigation.

Reference #58162 for specs and pricing.

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What Substrate Is Used For Soft Lithography To Make A PDMS Stamp?

A microfluidic researcher requested a quote for the following:

I am looking for diced 1cm by 1cm silicon substrates etched with microchannels. I am not sure what you have that would meet this specification. I am looking to do soft lithography to make a PDMS stamp that contains microchannels with cross sectional dimensions of ~5um by 10um but would potentially require various dimensions as well.

I will need some various microchannels that are ~800um^2 area on 1cm^2 diced Si substrates.

  1. Microchannels that are 5um wide with 5um spacings and 10um deep (80 channels) x2
  2. Microchannels that are 5um wide with 5um spacings and 5um deep (80 channels) x2
  3. Microchannels that are 5um wide with 10um spacings and 5um deep (50 channels) x2
  4. Microchannels that are 5um wide with 5um spacings and 3um deep (80 channels) x2
  5. Microchannels that are 5um wide with 10um spacings and 3um deep (50 channels) x2
  6. Microchannels that are 5um wide with 3um spacing and 5um deep (100 channels) x2
  7. Microchannels that are 5um wide with 3um spacings and 10um deep (100 channels) x2
  8. Microchannels that are 5um wide with 1um spacings and 10um deep (150 channels) x2
  9. Microchannels that are 5um wide with 1um spacings and 5um deep (150 channels) x2
  10. Microchannels that are 5um wide with 5um spacings and 1um deep (80 channels) x2
  11. Microchannels that are 5um wide with 10um spacings and 1um deep (50 channels) x2

This would make a total of 22 substrates. Is is possible to get these resolutions? As is outlined above, all of my Si channels will be 5um wide, but the spacings vary so that my PDMS mold will will contain various channel widths (10um to 1um). The depths also vary between 10um and 1um.

Let me know if you have these capabilities and pricing as soon as possible as I would like these within the next coupe of weeks if possible. If you have any dimensions already fabricated, I would also potentially be interested in those as well.

Reference #243280  for specs and pricing.

Square Silicon Wafers for Soft Lithography

An electrical engineer requested a quote for the following:

Do you provide 4 inch X 4 inch square silicon wafers? If so, what is the price? I will need about 10 pieces for soft lithography.

I do not have high requirements on the wafers. I think wafers like Silicon ID 2880 is OK for me, but by 4 inch X 4 inch square shape. Let me know if you have any more questions. Thanks!

UniversityWafer, Inc. Quoted:

100mm x 100mm P/B <100> 0.006-0.012 ohm-cm 525um SSP Test Grade

Reference #246314 for more specs and pricing.

Silicon Used As Raman Reference Measurment and SEM Substrate

A chemical engineer requested the following quote:

UniversityWafer, Inc. Supplied The Following:

Silicon Item #447 and 452. or reference #245500 for specs and pricing.

What Subtrates are Commonly Used For Soft Lithography?

Soft lithography can be performed on a variety of substrates, depending on the application and desired properties. Some common substrates used in soft lithography include:

  1. Glass: Glass is a widely used substrate due to its optical transparency, chemical resistance, and excellent surface flatness. It is commonly used in microfluidic devices, optical devices, and biosensing applications.

  2. Silicon: Silicon is another popular substrate, particularly for microfabrication and nanotechnology applications, owing to its well-established processing techniques and compatibility with traditional photolithography. Silicon is often used in the fabrication of microelectromechanical systems (MEMS) and semiconductor devices.

  3. Polymers: Various polymers, such as poly(methyl methacrylate) (PMMA), polystyrene (PS), and polyethylene terephthalate (PET), are used as substrates due to their low cost, ease of processing, and flexible nature. Polymers are often employed in flexible electronics, microfluidic devices, and biomedical applications.

  4. Metals: Metal substrates, such as gold, silver, and aluminum, can be used in soft lithography for applications requiring high electrical conductivity or specific optical properties. These substrates are often used for creating patterned metal films in plasmonic devices, electronic components, and sensors.

  5. Hydrogels: Hydrogels are used as substrates in soft lithography for applications in tissue engineering, drug delivery, and biofabrication. Their biocompatibility, tunable mechanical properties, and ability to swell with water make them suitable for mimicking biological tissues and creating 3D cell culture environments.

The choice of substrate depends on factors like the desired application, required material properties, and compatibility with the elastomeric material used in soft lithography, such as polydimethylsiloxane (PDMS).

Soft Lithography Applications

Soft lithography is used in a wide range of applications. It is useful for manufacturing microfluidic devices like those found in cell biology. These devices can be used for measuring the concentration of a substance in a sample or for controlling cell-based assays.

These devices are also commonly used in drug discovery to screen new compounds. Several companies are developing systems that use soft lithography to manufacture these devices, including Fluidigm and Surface Logix.

Unlike conventional photolithography, which requires expensive chrome masks, soft lithography uses elastomeric stamps and molds that can be made many times. The elastomeric elements are fabricated by casting and curing prepolymers of polydimethylsiloxane (PDMS), which has a variety of properties that make it suitable for use as a stamping or molding material. These include low interfacial free energy, chemical inertness, gas permeability, thermal stability, and ultraviolet and visible light transparency.
To cast the PDMS, a silicon base and a curing agent are mixed and poured over a master mold. Once the PDMS has been set, the mold is then removed.

Although the term “soft” is sometimes used to describe any elastomeric element that can be fabricated by soft lithography, this description is most appropriate for those molded and embossed on a mold, as shown in Figure 4. The most common elastomer used is polydimethylsiloxane.

It has many advantages over other elastomers, including superior thermal stability, high mechanical stiffness, and excellent sealing to a wide range of surfaces. It can also be easily modified to add or remove features, and it is generally biocompatible.

Another advantage is that PDMS can be injected into capillaries and removed after the structure has solidified to form a microstructure. This process is known as micro-molding in capillaries or MIMIC.
In addition, PDMS is a chemically inert, transparent, permeable, and mechanically flexible material. It is a common material for making microfluidics, as it can be shaped by laser and seal to various surfaces without leaking. It can be molded in many different shapes and is generally inexpensive.


University Researchers Favorite Silicon Wafer Used For Soft Lithography

A Ph.D. Assistant Professor of Mechanical Engineering requested the following quote:

Hi, I’d like to request a quote for the following item. ID 447, Diam. 76.2mm, Type P, Dopant B, Orien <100>, Thickness 0-100 um, Polish SSP, Grade Test. Q.ty: 200. I believe I have used these in the past for soft lithography with SU-8 photoresist and Sylgard 184 (PDMS). Could you please confirm if these are adequate for this process?

Buy Item 447 online or reference #252195 for specs and pricing. Silicon wafer item #447 work great and are often used by researchers for soft lithography masters for microfluidic devices.

3 Inch Silicon Wafers Used in Clean Room for Soft-Lithography Processes

A postdoctoral fellow requested a quote for the following substrate:

Hello, I am looking to purchase 3" silicon wafers to be used in the clean room for soft-lithography processes.silicon wafer used for soft lithography It would be polished on one side and etched on the other side. I think its thickness would be about 0.5 mm. As for the quantity, I will need it regularly but for the first order I would like to purchase 20-30 pieces. Would you please send me the quote for this product?

I am actually not sure about the specifications. I have already used them a lot in different labs but have never ordered them by myself, so am not sure what specs I need to choose (if any specific one). I need it to fabricate my structures (made of photoresists like SU-8) on its surface through photolithography process to further use it as a mold to produce my microfluidic PDMS chips. I have attached a few pics to help you see what type of silicon wafers I need and for which sort of applications.

Reference #257374 for specs and pricing.

Silicon Wafers Used To Fabricate Soft Lithography Templates

A university master's student requested help with the following:

My project requires the use of silicon wafers for a soft lithography product construction, and while I am in the small scale testing faze, I hope to quickly progress to larger scale designs. At this time I am wondering about the plausibility of ordering a custom SI wafer that is approximately 5 cm in width, and anywhere from 50-250 cm in length.

The quantity would depend greatly on the longevity of the soft lithography templates, but with that said I suspect we would likely order between 5 and 10 to start, and possibly more in the future should the project generate a new common practice for our lab.

As far as other specs go, the only ones I believe would be specifically necessary would be test grade (possibly prime down the line or should the templates last longer), and phosphorus dopant. Other specs like thickness, resistivity are less relevant because we are not using them with anything electrical.

Reference #259168 for specs and pricing.

Fused Silica Used For Polymer Replication Purposes Like Soft-Lithography

A senior researcher from a large corporation requested the following quote:

Use of the silicon/ fused silica/ITO wafers in our laboratory is for the fabrication of microfluidic substrates, to produce the channel features by micro machining processes in the clean room and then use machined substrate the for polymer replication purposes like soft-lithography or hot embossing.

Click the links below to purchase online.

Si Item #1080

ITO Item #2277

Fused Silica Item #3479

Or, reference #ONLQ38615 for specs and pricing.