An image of manual dispense being performed on an Apogee® Spin Coater
Jenny Adams Spin

The Art of Manual Dispense

While automated solutions offer convenience and consistency, manual dispense for spin coating remains an invaluable technique, providing precise control and unmatched flexibility. In this article, we’ll discuss the benefits of manual dispensing for spin-coating semiconductor substrates, offering insights, tips, and best practices for this approach.

Spin Coating Basics

Spin coating is a widely used technique in semiconductor fabrication. The process involves dispensing a liquid material onto a substrate, typically a flat surface such as a silicon wafer. The substrate is then rotated, causing centrifugal force to spread the liquid evenly across its surface. As the rotation continues, the solvent evaporates, leaving behind a thin, uniform film of the desired material. The speed of rotation, viscosity of the solution, and duration of spinning all play crucial roles in determining the thickness and quality of the resulting film. 

The Advantages of Manual Dispense

Automated dispense is crucial in spin coating for its efficiency, precision, and scalability. By automating the dispense process, manufacturers can achieve consistent and uniform coatings across large batches of substrates, reducing variability and improving product quality. While automated dispense systems offer efficiency and consistency, manual dispense allows operators to exert granular control over the deposition process, making it invaluable for research and development purposes, small-scale production runs, or when dealing with delicate substrates that require special attention. Manual dispense grants operators a significant degree of flexibility and real-time control. This flexibility enables on-the-fly adjustments to parameters such as solution viscosity, and dispensing rate, facilitating precise fine-tuning to achieve optimal coating results. Additionally, manual dispense is a cost-effective solution, particularly for organizations operating under budget constraints or working with specialized substrates. This versatility makes it an ideal choice for experimental setups, custom applications, or research involving novel materials. With manual dispense, operators can tailor the process to specific requirements, ensuring consistent and high-quality results.

Best Practices for Optimal Results

Material Preparation
Before initiating the manual dispense process, it’s essential to prepare the solution meticulously. Ensure proper solvent mixing, filtration to remove impurities, and degassing to eliminate air bubbles, which can adversely affect film uniformity.

Substrate Cleaning and Preparation
Thorough cleaning and preparation of the substrate surface are paramount to achieve uniform coating. Utilize appropriate cleaning techniques such as solvent rinsing, plasma treatment, or UV ozone exposure to remove contaminants and enhance adhesion.

Dispensing Technique
When manually dispensing the solution onto the spinning substrate, maintain a consistent and controlled flow rate to achieve uniform coverage. The Cee® integrated dispense hub ensures consistent dispensing at the wafer center.

Dispense Volume
It’s important to note, that dispensing too much or too little material may lead to less than desirable results. Too little may result in uncoated areas, while dispensing too much material may result in waste and backside contamination of the substrate. In general, a good starting dispense volume is approximately one milliliter per diameter inch of the wafer. For more details on process troubleshooting, refer to our article on Spin Coat Theory.

Spin Coating Parameters
Fine-tune spin coating parameters such as rotation speed, acceleration, and duration according to the specific requirements of the material being deposited and the desired film thickness. Experimentation may be necessary to determine the optimal settings for each application.

Practice Precision
Precision is key when performing manual dispense for spin coating. Take your time to master the technique and strive for consistency in every step of the process.

Regular Maintenance
Ensure that the spin coater and dispensing equipment are well-maintained to prevent malfunctions or irregularities that could compromise coating quality. It is extremely important to ensure a smooth, clean, and unobstructed dispense tip. Regular calibration and cleaning are essential for reliable performance.

Document and Analyze
Keep detailed records of process parameters, coating results, and any observed deviations. Analysis of this data can provide valuable insights for process optimization and troubleshooting.

Conclusion

Manual dispense for spin-coating semiconductor substrates offers a blend of precision, control, and versatility that makes it a useful tool in semiconductor manufacturing. By understanding the fundamentals, adhering to best practices, and leveraging the advantages of manual dispense, operators will achieve consistent and high-quality thin film coatings, driving innovation and advancement in the field of semiconductor technology.

Did you know?

Discover the best of both worlds with Cee®! While our Apogee® line offers automated dispense options, operators retain manual dispense capabilities for ultimate control and versatility. Want to elevate your spin coating experience? Talk with our sales team today!

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An Apogee® Spin Developer undergoing NRTL inspection.
Jenny Adams Spin

NRTL! What is it good for?

NRTL certification is becoming crucial for semiconductor equipment manufacturers as it ensures compliance with safety standards set by regulatory bodies like OSHA and ANSI. It also facilitates market access, instills customer confidence, provides liability protection, and encourages continuous improvement in safety and quality practices. For custom equipment, additional evaluations may be required. In years to come, NRTL certification will become essential for ensuring safety and reliability in the semiconductor industry.

What is NRTL?

In the realm of semiconductor equipment manufacturing, precision, reliability, and safety are paramount. The semiconductor industry operates in an environment where even the slightest deviation from standards can have far-reaching consequences. One critical aspect of ensuring safety in this industry is obtaining NRTL certification. In this blog post, we’ll delve into what NRTL is, its significance, and why it’s crucial for semiconductor equipment manufacturers.

NRTL, which stands for Nationally Recognized Testing Laboratory, is a designation granted by the Occupational Safety and Health Administration (OSHA) in the United States to organizations meeting specific qualifications for testing and certifying products. These independent organizations have demonstrated proficiency in evaluating products for compliance with established safety standards. Once a product and its manufacturer pass all required tests, the manufacturer receives Authorization to Mark (ATM). This allows them to affix the designated NRTL label to the product. Subsequently, the product is subject to strict control, prohibiting the substitution of unauthorized components or any variance in construction.

Importance of NRTL Certification in Semiconductor Equipment Manufacturing:

Compliance with Safety Standards

NRTL certification ensures that semiconductor equipment meets rigorous safety standards set by regulatory bodies such OSHA, the American National Standards Institute (ANSI), and UL. This includes standards for electrical safety, fire resistance, mechanical integrity, and other critical safety parameters. Compliance with these standards not only ensures the safety of workers but also minimizes the risk of equipment malfunction or accidents in semiconductor manufacturing facilities.

Market Access

Many countries around the world recognize NRTL certification as a benchmark for product safety. This opens doors to global markets, enabling manufacturers to expand their reach and compete more effectively on a global scale.

Customer Confidence

NRTL certification serves as a hallmark of safety for semiconductor equipment. Customers, including semiconductor manufacturers and facilities utilizing semiconductor processes, prioritize products certified by reputable testing laboratories for their safety assurance. It cultivates trust between manufacturers and customers, ensuring the equipment’s safety in operation.

Liability Protection

Obtaining NRTL certification can also offer liability protection for semiconductor equipment manufacturers. In the event of an accident or malfunction, having certified equipment demonstrates that the manufacturer took necessary precautions to ensure safety and compliance with standards. This may help mitigate legal risks and potential liabilities associated with product-related incidents.

Continuous Improvement

NRTL certification is not a one-time achievement; it requires ongoing adherence to standards and periodic audits by the certifying body. This encourages semiconductor equipment manufacturers to maintain a culture of continuous improvement in safety and quality practices. By staying up to date with evolving standards and best practices, manufacturers can enhance the safety, performance, and reliability of their products over time.

Custom Equipment Considerations:

While standardized equipment may undergo a streamlined certification process, custom equipment introduces variability that may necessitate additional evaluations. Manufacturers developing custom solutions should be aware that deviations from standard designs could impact safety and regulatory compliance. In such cases, obtaining Limited Production Certification or undergoing supplementary evaluations becomes imperative to validate the safety of custom equipment. As a best practice, manufacturers should be familiar with, and integrate these standards into their equipment design practices.

Conclusion:

In the dynamic and high-stakes environment of semiconductor equipment manufacturing, NRTL certification will become crucial for prioritizing safety and adherence to industry standards. Through collaboration with accredited testing laboratories and obtaining NRTL certification, semiconductor equipment manufacturers showcase their dedication to safety standards. In an industry where safety is paramount, NRTL certification serves as a key assurance for manufacturers, customers, and stakeholders alike.

Did You Know?

Beginning in February 2024, all standard Cee® Apogee® Spin Coater and Developer models will display the Intertek cETLus mark, showcasing our compliance with applicable US and Canadian safety standards. This showcases our proactive stance as Cee® moves towards NRTL listing for all standard products, underlining our unwavering dedication to safety across our entire range. We eagerly anticipate this next phase of excellence as we aim to consistently exceed expectations in providing top-tier semiconductor equipment to our esteemed customers.

An image of the Cee® 1300CSX Slide Debonder
Jenny Adams Bonding_Debonding

Beyond the Bond: Semiconductor Debonding Practices

Debonding is a vital step in advanced semiconductor manufacturing and 3D Packaging that involves separation of the device wafer from its carrier. This article includes an overview of a variety of debonding methods, including Laser, Thermal, Chemical, and Mechanical Debonding along with crucial factors for success.

The Vital Role of Debonding in Semiconductor Manufacturing

Before advanced manufacturing processes can take place, semiconductor wafers are temporarily bonded to carrier substrates. This temporary bond provides mechanical stability during processes like thinning, layer deposition, and device integration. Temporary bonding safeguards the delicate semiconductor components from damage, ensuring their integrity throughout the manufacturing process.

Debonding involves carefully detaching the device wafer from its temporary carrier substrate once the desired processes have been completed. This delicate procedure requires precision and finesse, and significantly impacts the quality, performance, and viability of the final device. Through precise debonding practices, manufacturers can fine-tune wafer properties, such as thickness, stress distribution, and material composition thereby optimizing electronic functionality.

Crucial Factors for Successful Debonding

For successful debonding, several factors must be considered:

Adhesive Material Selection: Choosing the appropriate adhesive material is essential. The adhesive’s properties, such as its strength, compatibility with the debonding method, and thermal and material tolerance impact the success of the debonding process.

Process Control and Parameters: Maintaining precise control over process parameters like temperature, pressure, and force is critical. Deviations from optimal conditions can lead to inconsistent or undesirable debonding outcomes.

Surface Preparation: Properly preparing the substrate surface is vital for achieving optimal adhesion and subsequent successful debonding. Adequate cleaning, surface treatment, and roughness can impact the bonding strength and efficiency of the debonding process.

Carrier Design: The design of the temporary carrier substrate affects the ease of debonding. An optimized carrier design can minimize stress concentrations and ensure uniform force distribution during the debonding process. Matching the carrier’s coefficient of thermal expansion to that of the device wafer helps prevent issues like wafer warpage and breakage post-debonding.

Compatibility with Substrate Material: Consider the compatibility of the debonding method with the properties of the substrate material, such as its thermal sensitivity, brittleness, and anisotropic behavior. Certain debonding methods may be better suited for specific materials.

Quality Control and Inspection: Regular monitoring and inspections throughout the debonding process help identify potential issues early on. This practice minimizes waste and ensures consistent, high-quality results.

Post-Debonding Processes: Account for any subsequent processes the substrate will undergo after debonding, such as cleaning, further material deposition, or device integration. Compatibility with these steps is crucial for the overall success of the manufacturing process.

Techniques for Debonding Semiconductor Substrates

Laser Debonding

Laser debonding employs high-energy lasers to selectively heat the adhesive interface, facilitating the separation of the wafer and carrier. This method offers precise control, minimizing wafer stress and ensuring a smooth detachment process. While laser debonding is adaptable, it doesn’t suit every scenario.  Consider substantial equipment costs, challenges with materials that share similar thermal coefficients, and the potential for contamination from vaporized materials.

Thermal Debonding

Thermal debonding relies on controlled heating to weaken the adhesive bond between the wafer and the carrier. This technique is well-regarded for its broad compatibility with various materials and efficiency in high-volume production scenarios. The controlled application of heat helps mitigate the risk of thermal damage to the wafer, preserving its structural integrity. Precise platen leveling is vital to prevent wafer stress, while accurate temperature control is crucial to avoid thermal damage. It’s noteworthy that the adhesives employed in thermal debonding are constrained to lower process temperatures when compared to alternative methods.

Mechanical or ‘Peel’ Debonding

Mechanical debonding relies on mechanical forces to separate the wafer from the carrier. This straightforward technique minimizes the risk of wafer damage when executed precisely. Also known as ‘peel’ debonding, the method employs mechanical forces to separate device wafers from carriers. It offers advantages such as simplicity, low risk of wafer damage, room temperature operation, and suitability for specific applications. However, anisotropic properties of the wafer (if applicable) should be considered, and careful application of force is extremely important.

Chemical Debonding

Chemical debonding employs specialized solvents to dissolve the adhesive layer, simplifying the substrate detachment process. Its ability to adapt to different materials makes it a versatile choice for various applications. Drawbacks include the necessity for chemical handling precautions, potential environmental repercussions, operator safety concerns, the need for specialized solvents, and the required use of perforated wafers. This debonding method is notably the most time-consuming.

Conclusion

Debonding device wafers holds immense significance in the multifaceted world of semiconductor manufacturing. Through laser, thermal, chemical, and mechanical debonding techniques, manufacturers achieve exceptional wafer quality and superior electronic performance. Furthermore, recognizing the critical factors for successful debonding ensures consistent and efficient outcomes. As the semiconductor landscape continues to evolve, debonding techniques will continue to drive progress, ushering in a new era of groundbreaking electronic advancements.

An image of Indium and Phosphorus transposed over debonded semiconductor thin-films.
Jenny Adams Bonding_Debonding

Bonding and Debonding Indium Phosphide Wafers

Indium phosphide (InP) wafers present challenges in bonding/debonding due to thermal mismatch, surface damage risks, and material compatibility issues. Cee® provides precision wafer handling tools with customized process controls designed to tackle the challenges presented by InP wafers. Experience reliable wafer handling and fully utilize the exceptional properties of InP for advanced electronics/photonics.

Introduction

Indium Phosphide (InP) wafers are prized for their exceptional electronic and optical properties, making them a cornerstone of cutting-edge semiconductor and photonic technologies.

Working with InP wafers presents unique challenges during bonding and debonding processes stemming from the material’s delicate nature and susceptibility to thermal stress. In this post, we’ll discuss the complexities of bonding and debonding InP wafers and how our state-of-the-art equipment mitigates these obstacles.

Obstacles in InP Wafer Bonding and Debonding

The bonding and debonding of InP wafers presents several key difficulties:

  • Thermal Mismatch – InP has a high coefficient of thermal expansion that differs significantly from common substrate materials like silicon or sapphire. Directly bonding InP to these materials with mismatched coefficients can lead to tremendous thermal stress. This stress can cause the wafer to warp, delaminate, or cleave during processing. It can also propagate through to fabricated devices, causing early failure. Careful and uniform thermal management is essential.
  • Material Compatibility – Not all adhesives are suitable for direct bonding to InP. Some may chemically interact with InP, etching the surface or leaving residues that contaminate devices. Strict selection of inert, non-reactive bonding materials is essential to avoid damage.
  • Surface Damage – The brittle nature of InP leads to significant debonding process risks that can damage the wafer. Examples of defects include microcracks, particulates, or other defects. Even minor damage can significantly hamper the performance and yield of devices fabricated on the wafer.
  • Bond Strength and Uniformity – Localized weak points can result from poor bond uniformity and strength which causes unwanted stress across the wafer. This often results in microcracks during wafer thinning leading to distortion, delamination, and premature device failure.  Carefully optimized bonding processes are needed to ensure uniformly robust bonds.
  • Debonding Stressors –  Careful control of debond process parameters such as temperature uniformity, force application, and handling is critical due to the fragile nature of thinned InP.
  • Adhesive Removal – Following debond both the carrier and device wafer must be cleaned, removing any residual adhesives from the delicate substrate. This is challenging, as any remaining adhesive or chemical damage during removal will degrade performance.

Meeting the Challenge Head On

At Cee®, we understand the complexities and challenges of using InP in bonding and debonding. Our advanced equipment has been meticulously designed and engineered to process fragile thinned wafers with precision and care. How do we accomplish this?

Tailored Process Control – Recipe-driven processes offer exceptional control during bonding, debonding, and cleaning. 

Material Compatibility – Our equipment is compatible with a wide range of bonding materials that are carefully selected for their compatibility with InP, ensuring reliable bonds without compromising device performance. 

Uniform Bonding – We specialize in achieving uniform and strong bonds across entire wafers. Our equipment’s precision engineering guarantees consistent quality, preventing stress-related issues.

Gentle Debonding – When it’s time to debond, our equipment ensures a controlled and gentle process, minimizing the risk of surface damage.

Handling – Specially engineered vacuum and handling solutions safeguard sensitive substrates through all steps of the bond, debond, and clean processes.

Cleaning – Baths are risky for fragile substrates such as InP. Gentle spray cleaning is efficient and safe, reducing time and the risk of breakage during the removal of residual adhesive material.

Application Support – With 35+ years of experience, our team has a high-degree of familiarity with process optimizations and support for a broad range of substrate materials and temporary adhesives. 

Customized Solutions – We understand that every application is unique. Our equipment can be tailored to meet your specific bonding and debonding requirements, ensuring optimal results for your InP wafers.

InP Wafer Bond/Debond Process Data

Following spin coat and bake processing on the Apogee® suite of tools, device substrate pairs 1-5 were bonded in the order shown using the bonding process below. All substrate pairs were successfully bonded with less than 5% bonded pair Total Thickness Variation (TTV) using the recipe shown below.

Apogee Bonder Recipe 
Temperature: 130° C       Force: 2000 N       Time: 180 sec
Evacuate Chamber To: 0.5 kPA       Pre-bond Delay: 15 sec

Device (100mm Indium Phosphide)Carrier (150mm Sapphire)
Sample 1112
Sample 2213
Sample 3391
Sample 4366
Sample 5402

The wafers were sent out to be thinned to 100µm. All 5 wafers were subsequently debonded without incident. Below are the 1300CSX recipe parameters.

Wafer Size: 100mm on 150mm            Upper and Lower Platen Temp: 190°C        

Lift Pin Descent: 60sec                      Lower Platen Stabilization: 15sec     Force: 4lbs     

Maximum Velocity: 2mm/s              Press Up Stabilization: 30sec

Average Process Time per Wafer: 6min 8sec 

Following debond, the device wafers were released onto custom handling devices. Both the device and carrier wafers were then cleaned on the Apogee® Spin Developer without issue.

*Process optimization is expected to reduce process time by as much as 20%.

Unlocking the Potential of InP

As InP continues to drive innovation in electronics and photonics, addressing the challenges of bonding and debonding is paramount. With our specialized equipment, you can overcome these challenges with ease, confident that your delicate InP wafers will be handled with the precision and care they deserve.

At Cee®, we’re dedicated to empowering your research and manufacturing processes. Our equipment not only streamlines the intricate world of InP bonding and debonding but also unlocks the full potential of this remarkable material for your applications.

Want to learn more? Contact our sales team today!

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Wafer Bonding Theory

Wafer bonding is crucial for compact and powerful devices. It involves coating a full thickness wafer with adhesive, bonding it to a support carrier wafer, and thinning it for downstream processes. Key factors impacting bonding quality include flatness (TTV), alignment, voids, temperature control, CTE match, and bonding force. Addressing these factors ensures uniform bonding, precise processing, and high device yield, leading to reliable and high-quality semiconductor devices.

Wafer Bonding Overview

Over the past years, temporary substrate bonding gained popularity alongside the demand for smaller, more powerful devices. Thin substrates (<100µm) pose challenges in handling, but a temporary wafer bonder solves this, reducing breakage risks.

In the bonding process, a full thickness wafer with devices is coated with a temporary adhesive to withstand downstream stresses. It’s bonded to a support carrier wafer. After thinning and backside processing (e.g., TSV, metal-plating), the stack undergoes debonding, cleaning, dicing, and packaging.

Cee Apogee Wafer Bond Debond Mount Demount Process Flow

Bonding Process Description

*This process description pertains to the Cee® Apogee® Bonder. While the processes of other manufacturers may vary slightly, the basic principles remain consistent throughout the industry. 

After referring to the adhesive material manufacturer’s specifications, the bonder platens are heated to the temperature required for the bonding adhesive. This temperature is chosen based on the point that the material liquifies in order to maximize adhesion. 

The device wafer is loaded onto the lower platen and centered using the built-in alignment fixtures. The carrier wafer is then placed and aligned on top of the device wafer. The mechanical alignment fixtures keep the carrier and device wafers separated at loading.

While the two wafers are held, the bonding chamber closes and vacuum is applied, evacuating air from the bonding chamber.  Programmable piston force “squeezes” the wafers together for a specified period of time, planarizing the bonding adhesive and ensuring full wafer coverage. 

Once complete, the chamber opens and the bonded wafer pair is removed and placed on a cooling plate. This allows the wafer stack to cool, setting the adhesive for maximum bond strength.  The bonded wafer pair is then ready for the next downstream process step.

Bonding Factors

In the realm of wafer bonding, various critical factors profoundly impact quality. During the early days of Moore’s law, these parameters held less significance. However, with shrinking feature sizes and sub-100 micron thicknesses, and the growing number of devices per wafer, addressing these challenges has become crucial. Any alteration in these five parameters can significantly influence repeatability and throughput.

Flatness (TTV)

A high total thickness variation (TTV) can result in poor bonding uniformity, causing voids or incomplete bonding between the wafers. These voids can create weak spots in the bond interface, affecting the overall structural integrity and performance of the bonded device. Later, when the device is ground thin, non-uniformity, or in severe cases, grinding through the wafer can impact depth and conductivity leading to device yield loss and affecting the depth of focus for photolithography.

Alignment of Device Wafer to Carrier

The alignment of the device wafer to the carrier is of utmost importance in semiconductor manufacturing. It ensures uniform bonding, precise processing, and high device yield for downstream processes such as patterning, handling fixtures, and feature placement. Accurate alignment enhances overlay accuracy, eliminates edge issues, and optimizes throughput efficiency.

Voids

Voids in wafer bonding present significant challenges. They cause total thickness variation issues (see Flatness (TTV) above), impacting the uniformity of the bonded layers and potentially leading to breakage or de-lamination. Additionally, voids can trap and expand air during high-temperature processes or debonding, increasing the risk of structural damage or device failure. To ensure the integrity and reliability of the bonded wafers, avoiding voids is crucial, and precise control of the bonding process is essential to mitigate these problems effectively.

Temperature

Precise temperature control is crucial for successful wafer bonding. It ensures uniform adhesive reflow, preventing TTV and material distortions. With accurate control, adhesion issues are minimized, guaranteeing reliability and repeatability. By using dual platens for heating and carefully monitoring material bonding temperature, optimal results are achieved without compromising material integrity.

Coefficient of Thermal Expansion (CTE) Match

A good CTE match reduces stress and strain during temperature variations, preventing delamination and cracking in the bonded layers. This alignment guarantees the stability and reliability of the bonded structure, vital for the performance and longevity of the semiconductor devices. Without a proper CTE match, the wafer bonding may result in defects and compromised device functionality, making it a critical consideration to achieve high-quality and durable wafer bonds.

Bonding Force

Bonding force determines the strength and integrity of the bond between two wafers or substrates. Optimal bonding force ensures that the wafers are firmly and uniformly pressed together, leading to a robust and reliable bond interface. Low bonding force can result in weak bonding and delamination, while excessive force can damage the wafers or lead to undesirable stress in the bonded layers. Achieving the right bonding force is essential for high-quality semiconductor devices, as it directly impacts their performance, yield, and overall reliability.

The Cee® Apogee® Bonder

Tailored for semiconductor production, the Apogee® Bonder is ideal for permanent and temporary adhesive bonding and accommodates a wide range of debonding materials such as peel, thermal slide, laser lift-off, and chemical release. It prioritizes high yield and throughput without the expense and complexity of full automation. With precise bonding for wafer sizes from 50mm to 300mm and a weekly volume of 400-1,000 wafers, it ensures critical process control for downstream thinned wafer processing, achieving an impressive ≥98% yield.

The bonder’s onboard control panel offers a user-friendly browser interface for real-time status updates. It enables schedule creation, remote process parameter updates, tool usage monitoring, and access to complete process history, logs, and analytics—tracking piston pressure, force, temperature, vacuum, and cycle time. With offline backup, data analysis, and push notifications to web-enabled devices, you’ll always stay informed 

An image of the Cost Effective Equipment Apogee Bonder for temporary bonding of semiconductor substrates

about the tool’s functionality and status, ensuring ultimate awareness of your process’ status anytime, anywhere.

The mechanical alignment fixtures are highly compatible with wafer notches and support the use of nonstandard wafers and carriers (alignment accuracy ≤ 0.5mm). Prior to bonding, the carrier and device wafer are separated, allowing for pre-bond evacuation and eliminating voids in the bond line. The dual ultra-flat (0.0005″ flatness specification), self-leveling heated platens with independent temperature controls ensure temperature uniformity of < 1% and bonding TTV as low as 5%. With a maximum bonding temperature of 300ºC and adjustable piston force (3.5 N – 12k N), accurate and precise bonds are guaranteed every time, with 10-N force resolution starting at 500 N.

Want to learn more? Contact our sales team today for more information!

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cee Case Studies

Case Study: Mini-Spin Coater

Mini-Spin Coater

A photovoltaic research institute required a compact spin coater to integrate with a robotic work cell. Cee® created a custom coater with a 120mm Teflon™ bowl, a mechanized lid, and auto-dispense functionality. This solution met the institute’s high-speed control needs, chemical compatibility, and space constraints. In production, the coater exceeded expectations, delivering safety and seamless communication with robotic handlers.

Introduction

The client, a photovoltaic research institute, required a compact spin coater optimized for 40mm x 40mm square substrates for solar applications. This system was required to integrate into their robotic work cell for automated wafer handling.

Key Requirements:

  • Compact size to fit into existing robotic work cells
  • Automated control interface for robotic synchronization
  • Vacuum chuck capable of operating with their end effector
  • Mechanized cover for robotic access
  • Automated dispense of materials
  • Programmable control of exhaust parameters with nitrogen purge
  • High-speed programmability up to 12,000 RPM
  • Precise speed control and stability during the spin cycle

Approach

The customer had a pre-defined process flow requiring a specialized cluster of tools. Additionally, the chemistry used in these processes raised operator safety and material compatibility concerns.

Readily available, turn-key, automated systems were inadequate to meet the customer’s functionality, integration, and budgetary needs. 

Exceptionally corrosive materials were not compatible with standard spin bowl construction materials such as HDPE or stainless steel. Workcell size constraints were incompatible with the standard 8″ Apogee® spin bowl and a mechanized spin lid was required to facilitate robotic interaction. In close collaboration, with the client and their chosen robotic integrator, a custom spin coater was designed.

Solution

To accommodate the client’s process needs, Cee® delivered a compact mini-spin coater with a 120mm teflon spin bowl, featuring an automated lid with auto dispense and nitrogen blow-off capabilities. The coater included nitrogen purge for operator safety and full recipe control of lid movement, dispense, exhaust, spin speed, auto-chuck homing, and communication protocols. 

The custom spin chuck was designed to accommodate end-effector access allowing ample room for the robot to place and remove substrates.

Sample Process:

  1. Command: Open lid 
  2. Wafer loaded by robot
  3. Command to Datastream™ GUI: Start recipe
  4. Spin coater recipe is executed
  5. Recipe Complete 
  6. Command: Open Lid
  7. Wafer removed by robot

In production, the spin coater performed exceptionally well and met or exceeded expectations by delivering on the following key requirements:

  • robotic handler integration
  • seamless communication
  • chemical compatibility
  • operator safety requirements
  • honors space constraints
  • automates essential process parameters
Cee® custom spin coater
Cee® custom spin coater
Cee® custom spin coater

Technical Details

Substrate Sizes:

40mm x 40mm x 2mm

Materials:

Chlorobenzene
DMF
DMSO
IPA
Acetonitrile
Ethyl acetate
Toluene
CBZ
Chloroform

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Case Study: Megasonic

The Megasonic Method

A semiconductor manufacturer faced challenges cleaning intricate structures on substrates. Conventional methods were inadequate, causing defects and lower device performance. Cee® suggested using megasonic technology, utilizing high-frequency sound waves to remove contaminants effectively. We chose the ProSys Stainless Steel MegPie™ transducer for its precision and adaptability, integrated with DataStream Software for process control. The solution led to reduced cleaning time, improved yield, and less structural damage.

Introduction

A semiconductor manufacturing company was facing significant challenges in cleaning high aspect ratio structures and hard-to-clean materials on their substrates. Traditional cleaning methods, such as chemical cleaning and spin cleaning, were proving insufficient to remove stubborn contaminants and residues from deep trenches, narrow channels, and complex surface geometries. As a result, the company was experiencing reduced yield, increased defects, and decreased overall device performance. They needed an advanced cleaning solution that could effectively and safely clean high aspect ratio features without causing damage to the delicate structures.

Approach

After careful evaluation of the customer’s challenges including substrate sizes, aspect ratio, device sensitivity, materials, throughput, and operator requirements, Cee® recommended megasonic technology for advanced cleaning capabilities.

The megasonic approach utilizes high-frequency acoustic energy (0.8-2 MHz) to create cavitation bubbles in the cleaning solution. These bubbles collapse near the surface of the substrate, generating powerful micro-energy that effectively removes particles and contaminants.

Because the acoustic transducer requires the presence of liquid material on a spinning substrate, the Apogee® 450 Developer was selected as the ideal base model.

For additional information on why the megasonic frequency is favorable over ultrasonic, check out this ProSys Boundary Layer blog post.

Solution

Loading the Cee® Megasonic
The Cee® Megasonic GUI
The Cee® Megasonic Spin Bowl

After an extensive evaluation of different megasonic cleaning systems, Cee® selected the ProSys Stainless Steel MegPie™ as the transducer most appropriate for the client’s use case. 

Transducer Selection: The ProSys Stainless Steel MegPie™ offered chemical compatibility and precision control over frequency and power output. This allowed the client to adjust cleaning parameters for different materials and substrate sizes ensuring optimal cleaning performance. 

Software Interface for Process Monitoring and Feedback: Megasonic controls were incorporated into DataStream Software, enabling complete recipe management to automate the cleaning process. Recipe options allowed for precise control over duty cycle, timing, and process power. Forward and reflective power values were captured in application logs for additional process optimization.

Fully Integrated for Process Flexibility: The megasonic transducer was affixed to a programmable positional arm allowing for adjustments to both radial position and z-axis. The radial positioning allowed the apparatus to serve for both conventional spin-cleaning/developing procedures and the acoustic cavitation of substrates. The recipe-controlled z-axis allowed for fine-tuning of reflective power and varying substrate thicknesses.

The megasonic process module was then packaged into an X-Pro II Workstation for consolidation of connection points, fume management, chemical storage, and ease of installation.

Result

The client achieved measureable improvements including significantly reduced clean time, accelerated throughput, improved yield, and a reduction in damage to structures.

Technical Details

Substrate Sizes

60mm х 48mm

30mm x 24mm

100 x 0.145-0.2mm Germanium CMP polished wafers

200 x 0.7-0.9mm Germanium CMP polished wafers

PhotoMask

4″ square

5″ square

Materials

Isopropanol Alcohol (IPA)

H2O2:NH3

DI Water

N2

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cee Accessories, Develop, Spin

Automated Dispense Systems

This article explores automated dispense options for spin coating applications in the semiconductor industry including cartridge dispense, pressure can dispense, and disposable syringe dispense. The article also touches on dispense controls, edge bead removal, and backside rinse, while highlighting the benefits of the Cee® line-up of Apogee® Spin Coaters. 

Automated Dispense Systems

Spin coating is a crucial technique in semiconductor manufacturing and thin film deposition, creating uniform films by applying a liquid solution onto a spinning substrate. To achieve the best results, efficient and precise dispensing of the solution is crucial. In this article, we’ll explore three distinct dispense options for spin coating applications: cartridge dispense, pressure can dispense, and disposable syringe dispense. Each option offers specific advantages, catering to dispensing needs in various applications.

Cartridge Dispense

Cartridge dispense utilizes a reservoir with low-pressure N2 or air pressure, ensuring a smooth liquid flow. The dispense valve allows for precise adjustment and repeatability of flow control, while an integrated suck-back valve efficiently pulls back the fluid after dispensing to prevent dripping. This method is ideal for accurate liquid dispensing in a wide range of applications and is particularly useful for materials with viscosity (cps) between 1 and 3,000. Cartridge dispense is commonly employed in both research & development and production applications, and it is suitable for dispense volumes ranging from 0.1ml to 50ml. Clean cartridges can be reused to promote cost-effective and sustainable practices.

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A rendering of Cee® Apogee™ Automated Cartridge Dispense

Pressure Can Dispense

Operating with a sizable 1-gallon (4-liter) reservoir using low-pressure N2 or air pressure, pressure can dispense offers easy adjustment and repeatability in flow control through its dispense valve. With its integrated suck-back valve, it becomes an excellent choice for applications involving repetitive dispensing of the same material, ensuring accurate and reliable liquid dispensing without unwanted drips. This method is suitable for materials with viscosity (cps) between 1 and 3,000 (or 1 to 10,000 if gravity-fed). Pressure can dispense is commonly used in both research & development and production applications and is suitable for dispense volumes ranging from 0.1ml to 100ml (or 1 to 100ml if gravity-fed).  A simple flush and clean process allows the pressure can dispenser to be repurposed for dispensing new materials, maximizing its versatility and efficiency.

Pressure Cans for the Cee® Apogee™ Spin Coater
Pressure Cans for the Cee® Apogee™ Spin Coater

Disposable Syringe Dispense

The disposable syringe dispense method is most commonly used for research & development applications. It utilizes disposable syringes as both the reservoir and pump for spin coating applications. This eliminates the need for cleaning or decontamination between samples or batches, saving valuable time. Pinch valve suck-back ensures a drip-free dispense. Available in 30ml and 55ml sizes, disposable syringe dispense offers a convenient and efficient way to achieve accurate liquid dispensing in spin coating applications. This method is suitable for materials with viscosity (cps) between 1 and 12,000 and is suitable for dispense volumes ranging from 0.1ml to 50ml.

Loading the disposable syringe for dispense
Loading the disposable syringe for dispense

Dispense Comparison

Hand DispenseDSD-1 SyringeCartridgePressure CanGravity-fed Pressure CanExternal Pump
Viscosity (cps)Any1-12,0001-3,000*1-3,000*1-10,0001-50,000
Dispense Vol. (ml)0.1-300.1-500.1-500.1-1001-1001-50
R&D✅✅✅✅✅❌
Production❌❌✅✅✅✅
Clean & ChangeDisposeDisposeFlush and CleanFlush and CleanFlush and CleanFlush and Clean

*Up to 5,000cps with upgraded dispense valve.

The Cee® Advantage

The Cee® line-up of Apogee® Spin Coaters provides a cutting-edge solution. With a closed bowl design and lid interlock feature, operators are safeguarded from unintentional dispense when the spinner lid is open. Moreover, Cee® excels in chemical compatibility, utilizing materials like stainless steel or chemically inert polymers for its wetted parts.

All Apogee® Spin Coaters feature an integrated 5-port dispense hub, for enhanced functionality. Dispense systems include convenient disposable nozzle tips in various sizes to cater to specific dispensing requirements. In addition to automated dispensing capability, users can manually dispense using a syringe or pipette, providing versatility and ease of use for precise liquid dispensing in spin coating applications.

Image of a Cee® Apogee™ Spin Coater's 5-hole dispense HUB
Image of a Cee® Apogee™ Spin Coater's 5-hole dispense HUB
Image of a Cee® Apogee™ Spin Coater's installed dispense tips
Image of a Cee® Apogee™ Spin Coater's installed dispense tips
An image of the Cee® spin coater dispense tip offerings

Dispense Controls

The dispense control box is a versatile tool, adjusting reservoir pressure for both cartridges and pressure cans. The integrated dispense valve allows minute adjustments to flow rate and suck-back, enabling precise and customizable dispensing for optimal results.

DataStream™ software seamlessly interfaces with common external dispense pumps using a trigger signal, ensuring efficient and synchronized dispense operations. Whether you have your own dispense system or not, DataStream™ software provides enhanced controls for achieving optimal results and process flexibility.

Dispense Options - Customized Solutions

Cee® offers a comprehensive range of options to cater to all your dispense needs including:

  • Teflon-lined pressure cans for metal-free requirements
  • Gravity-fed pressure cans for high-viscosity liquids
  • In-line filtration
  • Empty sensors
  • Pressure can sizes 1, 2, 3, 5, 10-gallon sizes
  • Cartridges from 175ml – 945ml

Edge Bead Removal and Backside Rinse - Improving Coating Process

Apogee® Spin Coaters and Developers can be optionally equipped with Edge Bead Removal (EBR) and Backside Rinse (BSR) capability to further enhance the coating process. EBR involves dispensing a solvent after the coating process to eliminate any buildup along the edges of the wafer using a movable stainless steel nozzle. Similarly, the Backside Rinse function employs solvent dispense to remove any contamination on the backside of the wafer. Both processes are adjustable for all standard wafer sizes and use a pressure-can solvent reservoir, for optimal wafer coating results.

For more information on Cee® Apogee® Automated Dispense, contact our Sales Team today!

An image of the word Nitrogen representing an article about Nitrogen (N2) Purge for Semiconductor Processing
cee Accessories, Bake, N2 Purge, Spin

Nitrogen Purge

Nitrogen purge is widely employed in the manufacturing of semiconductors. It is utilized to establish a low-oxygen setting for processing substrates. This method helps remove impurities, minimize oxidation, maintain uniform film deposition, and can be beneficial for meeting safety standards. 

Nitrogen Purge

Nitrogen purge is a common technique used in various industries, including semiconductor manufacturing, to create a low-oxygen environment during processing. Nitrogen gas is ideal for this purpose because it is chemically inert and does not react with other materials, but other inert gases can also be used. In semiconductor processing, nitrogen purge is used to eliminate contaminants, reduce oxidation, ensure consistent film deposition, and can be favorable for meeting safety requirements. 

The application of nitrogen purge in semiconductor spin coating can be traced back to the 1980s. During this time, semiconductor manufacturers were transitioning from manual coating methods to automated spin coating techniques. However, the new process introduced challenges, such as the formation of bubbles, which affected the quality and consistency of the coated films. 

N2 Purge In Spin Coating

The benefits of nitrogen purge in spin coating are numerous. Primarily, it reduces the oxidation of materials, such as polyimides, by spinning in an inert environment. Nitrogen purge also helps to reduce the formation of bubbles, resulting in a more uniform and consistent film deposition. In addition, it aids adhesion between substrate and coating, which helps to eliminate contaminants such as moisture, dust, and other airborne particles that can affect the quality of the final product. 

A diagram illustrating a Cee® Apogee™ Spin Coater Lid with optional Nitrogen (N2) purge configuration

The spin coater nitrogen purge lid functions by creating a closed environment around the substrate during the coating process. The polycarbonate lid is transparent, allowing for visual monitoring of the coating process. Nitrogen gas is introduced into the chamber, displacing the ambient air to prevent oxidation and contamination of the substrate, and ensuring that it retains its desired properties throughout all processing steps. 

N2 Purge for Baking Substrates

The benefits of nitrogen purge in substrate baking offer many of the same advantages as in the case of spin-coating. Additionally, baking in an inert environment can offer safety advantages. For example, if the wafer or the materials being processed are sensitive to air, oxygen, or other reactive gases, baking in an inert environment can help to prevent chemical reactions that could lead to safety hazards, such as fires, explosions, or the release of toxic gases. Overall, the use of an inert environment during the baking process can help to minimize the risk of safety hazards and ensure that the semiconductor manufacturing process is performed in a controlled and safe manner.  

Diagram illustrating the Cee® Apogee™ Bake Plate Hood with Nitrogen (N2) Purge

It is important to note that in semiconductor manufacturing, other safety measures, such as proper handling, storage, and disposal of hazardous materials, are also necessary to ensure a safe working environment.   

Final Thoughts

In conclusion, nitrogen purge is an essential technique used in semiconductor processing to improve the quality and consistency of coated films. The nitrogen purge lid plays a critical role in creating a low-oxygen environment that reduces the formation of bubbles, eliminates contaminants, and contributes to a safe operating environment. With the increasing demand for high-performance semiconductor devices, nitrogen purge is expected to continue playing a vital role in semiconductor manufacturing.

If you have additional questions, or to inquire about adding nitrogen purge to your equipment, contact our sales team today!