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Revolutionizing Thin Film Deposition: How KDF’s ERPP Technology Achieves ±1% Uniformity

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Revolutionizing Thin Film Deposition: How KDF’s ERPP Technology Achieves ±1% Uniformity

Summary:

In the race to meet the ever-tightening demands of microelectronics and optical device manufacturing, precision and repeatability are no longer luxuries—they’re requirements. Enter KDF Technologies’ Enhanced Rotating Planetary Pallet (ERPP), a breakthrough in sputtering system design that delivers metallic film uniformity better than ±1% and repeatability exceeding ±0.5%. By combining advanced planetary motion with linear scanning, the ERPP architecture redefines what’s possible in thin film deposition. Whether you’re engineering multilayer conductive barriers for integrated circuits or optimizing titanium tungsten coatings for acoustic filters, this next-generation platform ensures unmatched consistency, surface quality, and process control. Discover how ERPP is setting a new standard for deposition excellence.

 

 

Metallic coatings deposited using the KDF Enhanced Rotating Planetary Pallet (ERPP) exhibit exceptionally high film uniformity and tight process repeatability. This performance is driven by the synergistic effect of the concomitance of the planetary revolution and the system’s standard linear scanning mode. KDF Technologies has developed both reactive and non-reactive sputtering processes for metallic, semi-metallic, semiconductor, and dielectric materials. These processes consistently achieve film uniformity better than ±1% across the pallet, with repeatability exceeding ±0.5% from pallet to pallet. With this capability, we ensure high-performance processing of multilayer conductive barriers and contact materials essential for integrated circuits, in addition to delivering premium titanium tungsten films for adhesion and diffusion applications in both microelectronics and decorative technologies. Furthermore, the flexible programmability of the rotating motion will be examined in the context of its impact on improving deposition uniformity and tailoring surface morphology. With the ongoing evolution of thin-film device applications, deposition tools must meet progressively tighter specifications, delivering superior film uniformity and process repeatability to support next-generation performance.

Figure 1: The KDF 943i Sputtering System incorporates the ERPP technique alongside standard linear scanning, enhancing deposition uniformity and process flexibility.
Figure 2: KDF’s ERPP (Enhanced Rotating Planetary Pallet).

To address these demands, the KDF 900 series sputtering tools employ a combination of linear scanning and sophisticated rotating motion, as illustrated schematically in Figure 1. The novel scanning planetary substrate motion, enabled by the Enhanced Rotating Planetary Pallet (ERPP) ensures that all areas of the substrate are exposed to the sputtered material from various angles. It averages out angular distribution of sputtered atoms while the linear motion compensates for the non-uniform erosion of the target and non-uniform plasma density. Both combined maximize exposure to sputtered flux from all directions and averages out any spatial non-uniformities in the sputtering plume. We demonstrated pallet uniformity and run-to-run repeatability on the order of ±1% across a variety of metallic deposition processes, including tungsten (W) and titanium tungsten (TiW). These system advances now enable the precise and repeatable processing of complex multilayer metallic coatings, supporting critical applications such as optical devices and semiconductor components with exceptional uniformity.

Process with Standard Deposition
On standard KDF sputtering tools, metallic films such as tungsten (W) and titanium tungsten (TiW) are typically deposited onto a 12” × 12” pallet deposition zone, which scans across a 15” × 5” rectangular magnetron cathode. Deposition is performed via DC magnetron sputtering—either reactively using oxygen or nitrogen with elemental targets, or non-reactively from compound targets. The cathode is specifically engineered to optimize uniformity for metallic films, achieving an average thickness variation of approximately ±2% across four 4” wafers mounted on a planetary rotating pallet. Figure 2 presents a 6” wafer configuration of KDF’s Enhanced Rotating Planetary Pallet (ERPP) system.

Figure 3: A decrease in sheet resistance with increasing set point values suggests potential microstructural improvements, such as enhanced film density or grain structure.

Process with System Enhancement
In advanced microelectronic applications, tungsten (W) films are commonly employed as critical layers within frequency-selective components such as surface acoustic wave (SAW) and bulk acoustic wave (BAW) filters. For Solidly Mounted Resonator (SMR) configurations in BAW filters, multilayer silicon-based stacks with exceptional film uniformity and run-to-run thickness repeatability—on the order of ±1%—are required. Since the resonant frequency is inversely proportional to the thickness of the constituent layers, including tungsten, precise thickness control is essential for accurate frequency tuning. KDF 900 series sputtering systems, equipped with three- or four-target configurations, precisely controlled scan speeds, and multistep recipe capabilities, are well-suited for such demanding deposition tasks, offering fine resolution in film thickness across complex multilayer stacks.

To achieve stringent film uniformity targets without incorporating uniformity apertures, a new pallet design was introduced: the Enhanced Rotating Planetary Pallet (ERPP). The ERPP maintains the linear translation characteristic of standard KDF systems.

Figure 4: Pallet uniformity improved with increasing set point values, indicating enhanced deposition consistency across the wafers surface.

On top of the pallet sits a rotating platform, referred to as the ‘sun,’ which can rotate continuously over a broad range of speeds. Mounted to this platform are four wafer holders—each accommodating a 4-inch-diameter wafer—referred to as ‘planets.’ Each planet rotates at a fixed gear ratio relative to the sun, generating a full planetary motion of the wafers within the deposition plane. This motion is superimposed onto the standard linear translation of the pallet underneath the target. By integrating both rotational and translational movement, the planetary architecture averages out the spatial variations in deposition rate across the cathode, effectively enhancing uniformity across all wafers. It reduces the edge to center thickness variation. We are anticipating the step coverage on 3D features to be improved as well as we are varying the incident angle of the deposition while rotating. Figure 2 illustrates the schematic configuration of the Enhanced Rotating Planetary Pallet.

Figure 5: Surface roughness decreased with increasing set point values, indicating enhanced surface quality while maintaining consistent thickness.

 

Uniformity

Results
Tungsten (W) and titanium tungsten (TiW) films were deposited non-reactively using elemental W and TiW targets. Figures 3 through 5 summarize the results obtained using the Enhanced Rotating Planetary Pallet (ERPP) technique. Figure 3 illustrates a reduction in sheet resistance with increasing setpoint values under constant linear scanning conditions. Wafer rotation during sputtering was found to significantly enhance thin-film uniformity. This rotational motion helps average out the spatial non-uniformities inherent in the sputtering process, thereby improving thickness uniformity and stabilizing critical film properties such as sheet resistance.

Figure 4 presents the uniformity results for tungsten and titanium tungsten films deposited with the ERPP-enabled KDF 900 system. The planetary scanning motion consistently achieved within-wafer uniformities better than ±1% and pallet-wide uniformities better than ±2%. These results confirm the system’s capacity for high-precision film deposition. Table 1 summarizes the performance of planetary scanning for TiW depositions using standard 15-inch cathode.

In addition, Figure 5 demonstrates significant improvements in surface roughness. While wafer rotation contributes to enhanced thickness uniformity, its influence on surface roughness is multifaceted. Depending on process parameters—such as rotation speed, deposition pressure, and target power—surface roughness may either increase or decrease. Therefore, careful optimization of sputtering conditions is essential to achieve the desired film characteristics for each specific application.

Discussion
We have presented a detailed evaluation of metallic film deposition using a novel planetary scanning substrate carrier. This technique has significantly improved film uniformity and run-to-run repeatability. Specifically, it has enabled us to reduce metallic film uniformities from typical values of ±2% to less than ±1% across the pallet for non-reactive deposition processes.

The planetary deposition technique has potential applications for various other films, and we are currently investigating its advantages for optical films and features with high aspect ratios. Additionally, the ERPP may be integrated with a Plasma Emission Monitoring system and DC Pulsing.

 

 

 

Built for Production. Trusted for Repeatability. Backed by Kurt J. Lesker Company

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If you’re a production engineer, you know what matters: repeatable results, rugged equipment, and tools that scale with your line—without surprises.

KDF Technologies, part of the Kurt J. Lesker Company, delivers linear in-line sputtering systems that are the gold standard in reliability and performance. Whether you’re coating medical devices, razor blades, or solar display substrates, our systems are built to run—day in, day out—with minimal downtime and maximum consistency.

Why KDF?

✅ Repeatability You Can Rely On
Advanced process control, PEM, and stable reactive gas delivery ensure consistent coatings across batches and substrates.

✅ Rugged, Production-Grade Design
Our systems are engineered for real-world manufacturing—built to last, easy to maintain, and ready for high-volume throughput.

✅ Inline Architecture That Scales
Dual-pallet load-locks, high vacuum pumping, and optional pallet stackers support high-mix, high-volume production with minimal operator intervention.

✅ MRC Legacy, Fully Supported
We are the only provider that fully supports and services legacy MRC sputtering systems—offering upgrades, parts, and process continuity.

✅ Backed by Kurt J. Lesker Company
You benefit from the global support, vacuum expertise, and long-term reliability of one of the most respected names in thin film technology.

Contact Us:
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👉 Check out our Systems

Precision without Poisoning: Plasma Emission Monitoring in Reactive Sputtering with KDF Technologies

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Precision without Poisoning: Plasma Emission Monitoring in Reactive Sputtering with KDF Technologies

In the high-stakes world of thin film deposition, especially for functional oxides, nitrides and other compounds made by reactive sputtering with metals, precision is everything.

For example, slight variations in nitrogen content can impact the color of titanium nitride films dramatically.  Figure 1 shows a variation in color, based on nitrogen content, for titanium nitride thin films deposited by reactive sputtering.  Reactive sputtering, when done precisely, walks the fine line between optimal compound formation and catastrophic instability caused by target poisoning.

Fig 1: Samples of Titanium Nitride thin films that are overdoped or under doped with nitrogen. (Ref: N. Franzer, KJLC)

For scientists and process engineers new to the field of thin film deposition, one critical lesson must be learned: the difference between success and failure in reactive sputtering lies in millisecond-level process control.   This is where Plasma Emission Monitoring excels as a process control tool and why KDF Technologies has emerged as a leader in enabling production-grade precision on its in-line batch thin film sputtering systems.

The Reactive Sputtering Challenge

Reactive sputtering involves doing some inorganic chemistry in the sputter plasma, or at the surface of the substrate.  That is a discussion for another article.  Typically, a metal target is sputtered and the resulting sputtered adatoms collide and react with active gases, such as oxygen or nitrogen, introduced into the system, forming the desired product, such as SiO2 or TiN,  as a thin film.  Unfortunately, during the reactive sputtering process, if not controlled properly, some of the reacted material re-deposits on the surface of the target, masking some portion of the metallic sputter track, preventing it from being sputtered as a metal. If a sufficient amount of reacted material blankets the surface of the target, it becomes ‘poisoned’, where an insulating, non-metallic, layer builds up on the target surface causing the sputter rate to crash. Figure 2 shows the impact of nitrogen reactive gas flow on deposition rate, as the target gets poisoned.

Fig 2: Nitrogen Flow Rate and Deposition Rate, showing the collapse in Deposition Rate with a Nitrogen Overpressure.

 

The goal?  Stay in the sweet spot of the deposition process where sufficient reactive gas is supplied to make the desired film, without an excess of reactive gas causing re-deposition and poisoning at the target surface. Achieving this balance requires real-time feedback and sub-second responsiveness, which traditional gas delivery systems, like mass flow controllers, with their 250 millisecond response times, struggle to deliver.

Enter Plasa Emission Monitoring: 100 Millisecond Insight

KDF Technologies’ Plasma Emission Monitoring System (PEM) provides a solution to precision control of reactive thin film deposition processes with near 100 millisecond response times to changes in plasma conditions that promote poisoning. This is more than twice as fast as conventional mass flow controllers which work off of total system pressure, for instance.  The monitoring of optical emission spectra of ionized species, rather than total system pressure, provides near instantaneous insight into the chemical composition of the plasma and serves as a window into the composition of the thin film as it is deposited.  If the reactive gas species, for example nitrogen or oxygen, begins pushing the limits of the process and threaten to move the gas mixture out of the ‘sweet spot’ toward poisoning, the PEM system will detect an unfavorable mixture of precursors and automatically, within 100 ms, adjust the reactive gas flow- in real time.

Fig 3: An example of Target Poisoning based on Nitrogen Flow Rate, and the Hysteresis where reactive gas flow rate can be reduced and the target surface cleansed. (Ref: W. Sproul, US patent # 4,428,811  Jan 31, 1984).

 

This is more than monitoring the condition of the plasma, it is about control. The PEM systems provides a closed-loop feedback mechanism, which dynamically stabilizes the deposition process while maintaining conditions which optimize sputtering and deposition rates as well as film stoichiometry.

Batch Production with Precision:  The KDF Advantage

KDF’s in-line sputter systems benefit from 50 years of experience providing batch thin film production for industries including medical, electronics, solar panels, and sensors.  The systems are particularly suited for batch production of high-performance nitrides and oxides through a combination of mature, robust, system design and PEM controls.

Key System Features Include:

  • Optimized Gas Rings: These gas-channeling structures send reactive gases directly into the sputter plasma at the target surface where they will be most effective, in terms of reactivity and stoichiometry control, particularly with challenging gases like diatomic nitrogen.
  • Fast-Response Mass Flow Controller Placement: KDF systems are designed so that there is minimal latency between a control signal and the flow control function, by positioning the mass flow controllers adjacent to gas injection sites, minimizing delays, enabling the rapid modulation of flow required to avoid target poisoning.
  • Pulsed DC, RF and HiPIMS Power Options: PEM control regimes have response times fast enough to provide precise process control for a range of power supply types and deposition techniques, including High Impulse Power Magnetron Sputtering (HiPIMS).
  • Advanced Sputter Source Design: KDF’s novel cathode designs are optimized for reactive sputtering by minimizing the target area subject to poisoning. While maintaining the highest sputter rates, this also reduces arcing, extending target and cathode lifetimes while improving run-to-run process consistency.
  • Integrated Software Suite for Intuitive Operation: KDF’s propriety deposition system control software provide superb visual representations of process status, PEM data, and logs of all system parameters for traceability. The system is also designed to recover from faults, like running out of process gas, without compromising process integrity.

Process Development and Repeatability

One key advantage of any complex deposition system is the ability to quickly develop recipes for the deposition of new materials.  KDF systems, equipped with PEM, can utilize a single emission setpoint as the central parameter for tuning a process to produce specific film compositions, reducing the need to endless process iterations to find the ‘sweet spot’.

With a ‘tuned’ process in hand, it can be run multiple cycles with minimal drift, due to the ability of the PEM system to adjust reactive gas flows to accommodate the variations in plasma composition due to target aging. This is even more critical in multi-layer, thin film stacks, like thin film batteries and solar panels, where deficiencies in one layer degrade the performance of the entire stack.

Why it Matters

The application of thin, functional, films is ubiquitous, with nearly everything in our daily lives somehow enhanced with a coating of thin films. From semiconductors, to optics, to energy generation and storage, the demand for advanced, high-precision, coatings is growing and will likely never by supplanted by other approaches. These advanced films require extreme stoichiometric controls, combined with thickness uniformity, and process reproducibility.  For scientists and engineers working at the cutting edge of technology, these features are non-optional and mission critical.  KDF’s fully integrated solution simplifies process development while offering unmatched speed, precision, stability, uniformity, and repeatability.

In line with Your Process

In reactive sputtering, the race is not won by speed alone – but with precision at speed.  KDF’s in-line, batch thin film coating systems, with integrated Plasma Emission Monitoring, provide a robust, industry proven, platform with real-time process intelligence.   The system is designed to keep reactive deposition processes in the metallic regime while achieving the highest possible deposition rates, and complete control over film stoichiometry.  KDF’s advanced systems keep you in line with your process.

Advancements in Reactive Sputtering with KDF’s Sputter Sources and PEM

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KDF continues to innovate in the field of reactive sputtering with its specially designed and patented sputter sources and the integration of Plasma Emission Monitoring (PEM).

  • Sputter Sources: KDF’s sputter sources, such as the LMM sputter source, are designed for a reactive sputtering process. They reduce the build-up of reacted species on the target surface, decreasing the chances of potential differences building up, causing dreaded arcing and process instability.
  • In-situ Monitoring with PEM: KDF integrates PEM into the system with precisely placed optical sensors and easy-to-use software controls. PEM tracks the relative emission intensity of the ionized species in the sputtering plasma and controls the reactive gas to maintain an emission intensity setpoint. This setpoint correlates to the deposition rate and reactive gas concentration in the films, making it a great solution for rapidly developing a reactive sputtering process and repeatably depositing films of similar quality.

KDF is proud to implement PEM to further improve the capability and reliability of our production batch coaters. It is an excellent solution to control and develop a reactive sputtering process. Being fully integrated allows for straightforward recipe development, process monitoring, and parameter recording. We continue to be in line with your process!

Plasma Emission Monitoring (PEM) analyzes the light emission generated by ionized species during a physical vapor deposition (PVD) process. Observing this emission provides real-time insights into the plasma chemical makeup. When reactive gas, such as oxygen or nitrogen, is introduced to a deposition process, the intensity of light emitted by the different species of the sputtering plasma changes.  The PEM can then be used as a closed-loop control method to adjust the reactive gas flow to maintain the emission intensity of the species you choose throughout the entire deposition process. This makes a PEM a critical tool for a production batch coating reactive PVD systems for several reasons.

  • This allows for straightforward process development, as one parameter can be adjusted to easily explore different compositions of the deposited film.
  • The transition zone can be determined in a reactive sputtering process, and the operation in that zone can be maintained to achieve the highest deposition rate possible for the compound film.
  • By analyzing the plasma spectra, the PEM can indicate if there is any unwanted gas contamination.
  • The emission intensity of certain species is correlated with the deposition rate. This allows predictability in film thickness before the sample is removed from the PVD system.
  • After using the PEM to rapidly develop the process, it can be used to repeatably perform the same process to deposit films of similar characteristics.

At KDF, we took our effectively designed production batch-coating reactive sputtering systems and seamlessly integrated PEM. We have precisely placed the optical sensors to optimally view the sputtering plasma from any target in the system. Most importantly, the PEM is highly integrated into the KDF software, making it simple to use and easy to monitor. The KDF recipe builder allows the user to effectively modify the amount of reaction for a deposition process to create a film of a single composition or even deposit films of graded composition. During the deposition process the KDF software will graphically display the PEM information for the user. In the background the KDF software will monitor the control quality of the PEM, and it will quickly abort if there are any issues with trying to maintain a particular emission setpoint. Once the issues are resolved (say the reactive gas bottle was emptied and is now replaced) the KDF software can pick up the process from exactly when it aborted. Furthermore, the KDF software records all the important parameters and PEM information in a deposition process so a user can track operation over time.

Overall, KDF is proud to implement PEM to further improve the capability and reliability of our production batch coaters. It is an excellent solution to control and develop a reactive sputtering process. Being fully integrated allows for straightforward recipe development, process monitoring, and parameter recording. We continue to be in line with your process!

Enhancing Reactive Sputtering with KDF’s Unique Features

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KDF, with its extensive experience in designing reactive sputtering batch coating production systems, offers several optional features that set it apart from others. These features include:

  • Optimally Designed Gas Rings: KDF’s gas rings are designed to inject the reactive gas into the sputter plasma at the target. This is particularly useful when the reactive gas is nitrogen, an intermediately chemically active gas. The gas ring effectively distributes the reactive gas, utilizing the energy of the sputter plasma to make the reaction more favorable.
  • Pressure Control Package: All KDF systems are equipped with downstream pressure control and highly accurate Mass Flow Controllers (MFCs). This technique maintains a constant rate of reactive gas injection throughout the process, making it the most preferable pressure control technique during reactive sputtering.
  • Prompt Gas Injection: The reactive gas Mass Flow Controllers are located as close as possible to the gas injection port on the chamber. This allows for prompt changes in flow rates with little delay.
  • Power Supplies: KDF utilizes pulsed DC supplies with a wide range of pulse frequency and reverse time for conductive target reactive sputtering. This outpaces the arcing and creates a more stable high deposition rate process. KDF also specializes in reactive RF sputtering with in-house made and system-tuned matching networks.

 

KDF Reactive Sputtering System

KDF has extensive experience designing reactive sputtering batch coating production systems. What sets KDF apart are the several optional features that can be added to our reactive sputtering systems.

  • Gas Rings
    • KDF has optimally designed gas rings to inject the reactive gas into the sputter plasma at the target. This is extremely useful, especially when the reactive gas is nitrogen. Since diatomic nitrogen is considered an intermediately chemically active gas, it is best to cycle it through a plasma to crack it into monoatomic form. Essentially, the gas ring effectively distributes the reactive gas to utilize the energy of the sputter plasma to make the reaction more favorable.
  • Pressure Control Package
    • KDF systems are all equipped with downstream pressure control and highly accurate Mass Flow Controllers (MFCs). Downstream pressure control is where the high vacuum gate valve will automatically adjust its position to maintain deposition pressure, and the MFCs can be held at a constant flow rate. This is the most preferable pressure control technique during reactive sputtering, as a constant rate of reactive gas is injected throughout the process.
  • Gas Injection
    • The reactive gas Mass Flow Controllers are properly located to be as close as possible to the gas injection port on the chamber. This allows for the flow rates to be promptly changed with little delay.
  • Power Supplies
    • If using a conductive target to reactively sputter, KDF utilizes pulsed DC supplies with a wide range of pulse frequency and reverse time. This gives more capability to outpace the arcing and creates a more stable high deposition rate process. KDF also specializes in reactive RF sputtering with matching networks made in-house and tuned to each system.
      • High rate processes for deposition of dielectric films have been developed using Pulsed DC reactive sputtering on scanning batch tools. A typical high rate process for the deposition of silicon dioxide films from a conductively doped silicon target would allow the formation of nearly one micron of SiO2 in fifteen minutes, as compared with nearly five hours when RF magnetron sputtered from a quartz target.
        (Ref: Photonics Spectra, pp. 30-31, November 2002)
  • Sputter Sources
    • KDF has specially designed and patented sputter sources that are a great match for a reactive sputtering process. The LMM sputter source, for example, has nearly full-face erosion of the sputter target greatly reducing the build-up of reacted species on the target surface. Also, the inset sputter sources only have target material where the sputter plasma creates an erosion groove for high target utilization and limited area to build up reactive species on the target surface. By reducing the varied amount of reaction on a target surface decreases the chances of potential differences building up causing dreaded arcing and process instability.
  • In-situ Monitoring
    • KDF effectively integrates Plasma Emission Monitoring (PEM) into the system with precisely placed optical sensors and easy-to-use software controls. The PEM tracks the relative emission intensity of the ionized species in the sputtering plasma and controls the reactive gas to maintain an emission intensity setpoint. This emission setpoint correlates to the deposition rate and reactive gas concentration in the films. It is a great solution for rapidly developing a reactive sputtering process and repeatably depositing films of similar quality.

We offer the most advanced and reliable physical vapor deposition batch in-line sputtering tools at the industry’s lowest cost of ownership. KDF systems can be customized to meet the customer’s needs and cover a wide variety of process requirements for the mainstream silicon, emerging materials and flat panel display markets.

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