Plasma Measurement

高性能プラズマ計測システム
Avantes社の高性能・万能型ファイバー入射型分光器は新開発の迷光が極端に少ない光学ベンチ(AvaBench-ULS)を採用し、用途に応じたスリット・グレーティングを選択することにより、高速で非常に高い波長分解能を実現しています。

プラズマのより高性能な計測の為に開発された
高性能プラズマ計測システムは、Avantes社のベストセラー製品である高性能・万能型分光器を複数チャンネル使用した、マルチチャンネル分光器システムです。
専用に開発された分析用ソフトウエアと独自の光ファイバー、オプション等と使用することによりプラズマの幾つもの放射ピークを紫外域～近赤外域まで的確に捉えることが可能で、これまでに無い、高波長分解能での計測が実現します。

◆低コスト、 高波長分解能プラズマ計測システム
波長域 200 ～ 1030nm の高性能 4ch 分光器を使用したシステムで 0.18 ～ 0.22 の高波長分解能での計測を実現しました。
独自開発の AvaSoft 分光器ソフトウェアにより、あたかも１台の分光器で計測しているが如く、4ch がスムーズに動作 ・ 計測でき、 デスクトッ
プ上で操作できます。 一体型なので無駄が無く、 コスト的にも費用効果が高い、 高波長分解能小型プラズマ計測システムです。
グレーティング

スリット

波長分解能

4ch デスクトップ型

・ UC (200-458nm)
・ VC (455-683nm)
・ NC (680-974nm)
・ NC (870-1030nm)

10μm
10μm
10μm
10μm

0.18nm0.19nm0.20nm0.22nmAvaSpec-ULS2048-USB2
４台内蔵

オプション
・ DCL-UV/VIS detector collection Lens
・ OSF-600 order sorting filter ( 必要な波長に）

AvaSoft-Full

ＡｖaSpec 用万能ソフトで ch 毎の計測 ・ データ
集積 ・ 処理 ・ 変換 ・ 表示などの機能の基本ソフト

SPECline-A

分析 ・ 解析用ソフト

ファイバー入射型
分光器

ソフトウェアファイバー

FC4-UVIR400-2

多分岐ファイバー４ｘ400μm fiber◆超高波長分解能プラズマ計測システム
さらに高感度 ・ 高波長分解能でプラズマ計測する為のシステムで、 波長域 200 ～ 1070nm の高性
能 8ch 分光器を使用して 0.10nm の高波長分解能での計測を実現しました。
独自開発の AvaSoft 分光器ソフトウェアにより、あたかも１台の分光器で計測しているが如く、8ch がスムーズに動作 ・ 計測でき、 紫外域から近赤外域までカバーできます。 最大 10ｃｈまで拡張でき、 ラックマウントに収納した使い易い形です。 一体型なので無駄が無い高波長分解能小型プラズマ計測システムです。

グレーティング
8ch ラックマウント型
ファイバー入射型
分光器
AvaSpec-ULS2048-USB2
8 台内蔵

スリット

波長分解能

・ UE (200-320nm)
10μm(318-420nm)
10μm(417-505nm)
10μm
・ VE (500-565nm)
10μm
・ VD (565-670nm)
10μm
・ VD (688-750nm)
10μm
・ NC (745-930nm)
10μm
・ NC (920-1070nm) 10μm

0.10nm0.10nm0.10nm0.10nm0.12nm0.14nm0.20nm0.22nmオプション
・ DCL-UV/VIS detector collection Lens
・ OSF-600 order sorting filter ( 必要な波長に）

AvaSoft-Full

ＡｖaSpec 用万能ソフトで ch 毎の計測 ・ データ
集積 ・ 処理 ・ 変換 ・ 表示などの機能の基本ソフト

SPECline-A

分析 ・ 解析用ソフト

ソフトウェア

ファイバー

用途：

半導体

FC8-UVIR400-2

太陽電池

多分岐ファイバー 8ｘ400μm fiber

核融合炉

剃刀の刃

https://www.phototechnica.co.jp

ガラスコーティング〒336-0017 埼玉県さいたま市南区南浦和 1-2-17

TEL:048-871-0067 FAX:048-871-0068
e-mail:voc@phototechnica.co.jp

Spectroscopy Applications for Plasma Monitoring
Spectrometers

Exploring the use of optical emission spectroscopy(OES) as a form of plasma monitoring during themanufacturing of electronics
Plasma is an ionized gas under pressure and subjected tointense heating or electromagnetic fields to the point thatelectrons and positive ions are unbound. Plasma is one of thefour fundamental states of matter, but it does not exist on
Earth naturally and must be generated by applying heat andpressure. What makes plasma unique from other states ofmatter is its behavior. The speed of atoms in a plasma arehigher than in a gas. This movement of charged particles creates an electric current within a magnetic field, and while theoverall charge of a plasma is usually neutral, it is also highly
conductive.

Plasma etching (Shutterstock)

Even though plasmas are rare at normal Earth conditions, plasma is considered to be the predominant state of matter
throughout the universe. For instance, the sun and stars are examples of fully ionized plasma, while neon lighting is only
partially ionized.
Plasmas are used for a large number of applications in spectroscopy. Most commonly might be thin film depositionand photo-resist etching for semiconductors and solar collectors, but plasmas also have applications in biomedical andaerospace, along with other industries. Plasma diagnostics demand high-resolution spectra and high-speed data capturethat Avantes is known for. Our instruments can be found in plasma research and industrial environments all over theglobe.

Applications

When a matter turns into plasma, it can be monitored using optical emission spectroscopy (OES). As each atom’s emission
spectrum is unique, it is possible to measure the spectra and identify the atoms present in the plasma. Plasma monitoringis used in a variety of industries to identify and detect the additions in and during a plasma process, or to control the process or sequence in general.
In the semiconductor industry, plasma monitoring is used to measure the process during etching of a photo resist, alight-sensitive material which is used to form a patterned coating on a surface. Plasma monitoring facilitates the process
through, for example, end point detection.
Optical emission spectroscopy (OES) can be used to monitor the contamination of the repositioning of hydrocarbons fromchamber wall elements. OES may also be used in the monitoring of co-deposition of deuterium and tritium. OES is often
used in the biochemical industry to monitor surface modifications using plasma etching to improve biocompatibilityof materials.
Thin layers of carbon impurities are found on optical components in both fusion reactors and lithography devices, thereby
reducing the reflectivity of the mirrors. Plasma etching has been proposed as a method to remove these impurities, without damaging the optics. Optical emission spectroscopy is a suitable tool for in situ monitoring of the etch process.

Optical emission spectroscopy in the fabriction of integrated circuits

Plasma processing is one of the most widely used techniques in modern electronics manufacturing, particularly when it
comes to the fabrication of integrated circuits (ICs) and other types of microelectronics. Many large-scale ICs can containas many as 400 different individual layers, and to build such complex structures each layer typically requires both an
epitaxial growth and a plasma etching step. For proper functionality of the IC, it is critical during the etching process thatthe material from the newly applied layer being etched is removed completely without damaging the subsequent layer
below. To make the process even more difficult, plasma etching must be performed under vacuum to prevent deposits ofunwanted contaminants. Luckily, during the ionization process, vast amounts of energy are transferred to the ionizedmaterial, which results in the release of massive amounts of light.

Exploiting changes in energy stateThis emission of photons results from the atoms being first excited to a higher electronic state, and then spontaneouslydropping back down to the ground state. During the process, since the total energy is conserved, the emitted photons
must have an energy equal to the difference between the excitation state and the ground state. The amount of energy
transferred in this process is a unique property of the particular species of atom undergoing the transition. Since the frequency of the light, and therefore its wavelength, are directly proportional to the energy of the photon, by collecting the4 | info@avantes.com | www.avantes.com

emitted light and measuring its spectrum, it is possible to determine which elements are present.
This technique, known as optical emission spectroscopy (OES), gives process engineers the ability to monitor the plasma
etching process and detect the endpoint when a layer is completely removed. By providing this real-time monitoring
capability, IC manufacturers can fully automate the etching process, without fear that they will over or under etch thelayer. Figure 1, courtesy of Professor Richard van de Sanden’s Plasma and Materials Process (PMP) group at the Eindhoven
University of Technology, shows an example of this process where the 431nm CH line was monitored during the etchingprocess by collecting the emission and coupling it into one of our spectrometers via a fiber-optic cable. Additionally, OES
has the intrinsic benefit of automatically notifying the user when they have reached the previous growth layer by theappearance of spectral lines corresponding to the layer below.

Figure 1. Etching depth and 431 nm spectral peak intensity for monitoring CH content (Eindhoven University of Technology

Working in vacuum environments

When possible, it is preferable to monitor the process through an observation window in the vacuum chamber utilizing acollection lens (sometimes referred to as a collimating lens) placed near the window to couple the light into a fiber opticcable. Unfortunately for many large scale industrial epitaxial growth reactors and plasma etchers, it is not always possible
to do so, in these cases, it is necessary to utilize vacuum seal fiber optic feedthroughs to bring the fiber closer to the wafer.
While more complex, vacuum feedthrough fiber-optic assemblies are mature technologies that are commercially available.

Resolution is key

As with most atomic spectroscopy techniques, OES generally requires very fine spectral resolution to differentiate between similar atomic species. For this reason, compact spectrometers are an ideal choice for this application. For example,
the AvaSpec-ULS4096-EVO, as shown in Figure 2, can provide 0.05 nm resolution within the range from 200-400 nm using
a 3600-grove density grating. Additionally, this spectrometer has a CMOS detector array which is ideal for high light levelapplications such as this one because of its superior linearity and dynamic range when compared to more commonlyused CCD detectors. When combined with proprietary high-speed electronic triggering, data transfer rates, and analog
and digital I/O capabilities the AvaSpec series provides seamless integration into high-speed wafer etching systems.

Figure 2. AvaSpec-ULS4096CL-EVO (Avantes)

info@avantes.com | www.avantes.com | 5

Spectral range v. resolution
Spectrometers

While some OES systems may be designed as “fit-for-purpose” instruments which only require a limited spectral range toidentify a select number of atomic species, the vast majority of OES applications involve the identification of a wide rangeof elements. As a result, these systems need rather large spectral ranges, leading to a fundamental limitation of fixed grating spectrometers, the inverse relationship between spectral range and resolution.
Avantes’ instruments for OES benefit from an optical design which offers a superior response, allowing for 0.5 nm resolution over the full range from 200-1100 nm. Additionally, these spectrometers are designed to be multiplexed, or concatenated together, enabling multichannel operation. This allows each spectrometer in the system to be optimized for spectral
resolution over a small range, typically of 200 nm – 300 nm. In these multiplexed systems, the collected OES signal can be
split evenly amongst the instruments using a multichannel fiber optic bundle. This provides a more stable, faster, and lessexpensive alternative to large scanning spectrometer alternatives. Depending on the integrator’s preference, these multichannel spectrometer systems are available as both individual OEM board components, or custom turn-key rackmountsystems as shown in Figure 3.

More applications for OES

While endpoint detection of semiconductor plasma etchingis the most popular application of OES used to date, there aremany scientific and research applications for this technology
as well. A full analysis of each of these options is beyond thescope of this application note, but it is worth briefly
mentioning a few of them here.
OES has been widely deployed in metal foundries formonitoring steel, copper, and aluminum purity byFigure 3. AvaSpec multi-channel fiber-optic spectrometers (Avantes)
measuring the emission from these metals in the mutantform. OES can also be used in quality control laboratories as a low-cost alternative to mass spectrometry (MS), especiallywhen combined with inductively coupled plasma (ICP). IPC-OES is commonly used in the automotive, aviation, and recycling industries for rapid analysis to verify elemental content where ICP-MS would be overkill. OES is also used effectively
in the monitoring of laser ablation spectrum during metallic additive manufacturing processes.

Why choose Avantes for your plasma application?
• Avantes supports synchronous measurement across multiple spectrometer channels to acquire the spectrum of a plasma at the same moment every time. AvaSoft software stitches these spectra together.
• Avantes offers high-resolution measurements (0.1 nm FWHM or higher) to resolve and identify atomic lines and molecular spectra within plasma.
• Avantes provides the option to acquire spectra at high speeds (ms time scale) and communicate events via digital andanalog ports.
Plasmas are known for their many emission peaks, located closely together. To separate these peaks, Avantes has developed multi-channel spectrometers, featuring much higher resolution than any stand-alone device. Avantes has made twomulti-channel spectroscopy bundles especially developed for plasma monitoring. To find out about the possibilities ofthese bundles, please visit our website or contact us directly.

About Avantes

Avantes is the leading innovator in the development of fiber-optic spectroscopy instruments and systems with 25 yearsof experience developing customer-defined configurations. With a long history of consulting with clients across diverse
industries and applications, Avantes is an experienced partner, equipped to guide customers who want a solution tailoredto their application and research needs. Avantes offers customers the peace of mind that the solutions they purchase will
meet, and exceed, their expectations.
info@avantes.com
www.avantes.com

info@avantes.com | www.avantes.com

www.phototechnica.co.jp〒336-0017 埼玉県さいたま市南区南浦和 1-2-17

TEL:048-871-0067

FAX:048-871-0068

e-mail:voc@phototechnica.co.jp

Introduction of Avantes Plasma application

1

MultiChannelHigh Resolution spectrometer2

8CH (resolution 0.1nm) , 4CH (resolution 0.2nm)

3CMOS detector have very fast timing about minimum integration time is 9us.
Data processing of USB 3 in 2048CL is about 350us.

4

Avantes spectrometer have lots of kind gratings. U is UV range. V is visual range. I is Infrared range.
A is 300 /mm, B is 600 /mm, C is 1200/mm, D is 1800 /mm, E is 2400 /mm, F is 3600 /mm

5The unit of resolution is nano meter in FWHM (Full Width Half Maximum ).
The resolution is determined by slit size (um) and grating lines.
For example at the grating line 3600 and slit size 10um, the resolution is 0.06-0.08nm.

6Trigger In (外部トリガーケーブル機能

Trigger in is laser control (trigger) spectrometer.

7

Avantesプラズマ測定例

Wall Flux Measurements

8

'Spectrum measurement of the JET wall'

9

Spectroscopy Applications for Plasma Monitoring

Exploring the use of optical emission spectroscopy (OES) as aform of plasma monitoring during the manufacturing ofelectronics

Plasma etching (Shutterstock)10

Etching depth and 431 nm spectral peakintensity for monitoring CH content

11Thanks for your attention!

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