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UPGRADES

AUTOMATIC ENDPOINT DETECTORS

AUTOMATIC ENDPOINT DETECTORS

Endpoint Detectors (EPD) are an important tool for achieving optimal process results. The use of an EPD ensures processes are carefully controlled and consistent, to ensure reliable repeatable results are achieved wafer-to-wafer and batch-to-batch. Several techniques exist and it is vitally important to understand the strengths of each and how they fit with your process requirements to achieve what you need.

We offer EPD upgrades under these two categories:

  • Optical Emission Spectroscopy (OES)
  • Laser Interferometry
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Horiba LEM Endpoint

Optical Emission Spectroscopy (OES)


Options Ocean Insight USB 4000 Verity SD 1024GH Verity SD 1024G
Wavelength range 200 - 850 nm 200 - 800 nm 200 - 800 nm
Spectrometer Real time Real time Real time
Endpoint Yes Advanced algorithms Advanced algorithms
Chamber condition analysis Yes Yes Yes
Etch process monitor Yes Yes Yes
Reprocess No Yes Yes
Resolution Good for general single layer process Superior for complex multilayer Excellent for complex multilayer
Suitable for PECVD, RIE, ICP-RIE, CVD and ALD Systems RIE and ICP-RIE Systems RIE and ICP-RIE Systems
Example Applications PECVD chamber clean, SiO2/SiNx etch, PR strip, general purpose etching SiO2/SiNx etch, GaAs/ AlGaAs/ GaSb/ AlGaSb, InP/ InGaAs/ InGaAsP/ InAlGaAs, Metals, Plasma analysis, Deep Si, GaAs VCSEL SiO2/SiNx etch, GaAs/ AlGaAs/ GaSb/ AlGaSb, InP/ InGaAs/ InGaAsP/ InAlGaAs, Metals, Plasma analysis

Optical emission spectroscopy (OES) monitors the light emitted by the plasma. Measuring the intensity of light emitted at a specific wavelength in a spectrum allows a relative measurement of the concentration of a given species.

Etch by-products and gas species have characteristic emission wavelengths, so process endpoints can be detected by looking for changes in these emissions as the etch reaches a new layer. OES end pointing typically requires an etched area of several cm2 to provide a detectable concentration of etched species in the plasma, depending also on etch rate and plasma emission intensity.

A popular application of OES is in the plasma cleaning of PECVD chambers, but the same principle is also used for etch chambers. In PECVD for example, measurement of the fluorine emission intensity is used to determine the endpoint of chamber plasma cleaning. During cleaning the fluorine concentration will be low as it is being consumed by the etching process, but it will rise sharply when the chamber walls become clean, providing an endpoint.

Benefits of OES Endpoint Detector

  • Allows a precise stop on a particular layer, improving throughput and yield
  • Improve process reproducibility
  • Reduced cost of ownership
  • Reduced particulate generation by preventing over-cleaning, leading to improved process yield
  • Extended life of chamber components due to less over-cleaning
  • Enables monitoring of chamber condition and process ‘health’ in real time

OES Endpoint Detector Upgrade Suitability

Upgrade Available on
Ocean Optics USB4000 Spectrometer PlasmaPro 100, Polaris, PlasmaLab 100, PlasmaLab 133, PlasmaPro 80, FlexAL, PlasmaPro 800
Verity SD1024G Spectograph PlasmaPro 100, PlasmaLab 100, PlasmaLab 133
Verity SD1024GH Spectograph (High Performance) PlasmaPro 100, Estrelas, PlasmaLab 100, PlasmaLab 133
Verity PM140 Detector 704 nm PlasmaPro 80, PlasmaPro 800

OES Upgrade Process

Most endpoint detection upgrade installations are typically completed within two days, including travel and introductory training on operating an endpoint detector.


For pricing, a free consultation, and more information on optical end point detectors, please contact your local customer service sales team.

Laser Interferometry

Options Laser Endpoint Horiba 670nm Laser Endpoint Horiba 905nm Laser Endpoint Intellemetrics LEP500 670nm Laser Endpoint Intellemetrics LEP500 980nm
Movement XY and tilt adjustment XY and tilt adjustment
Sample image magnification x50 x50
Laser wavelength 670/ 905 nm 670/ 980 nm
Laser spot size 30 to 60μm  Working Distance dependant. 8 to 40μm at FWHM
Layer structure modelling No Yes
Suitable for RIE and ICP-RIE Systems RIE and ICP-RIE Systems
Example Applications SiO2/ SiNx, Metals, GaAs/ AlGaAs/ GaSb/ AlGaSb, PR strip, Failure Analysis Metals, GaAs VCSEL, GaAs/ AlGaAs/ GaSb/ AlGaSb, InP/ InGaAs/ InGaAsP/ InAlGaAs, PR strip
Optional Motorised "XY" table for laser interferometer is available as optional extra with these two upgrades. The Motorised ""XY"" stage option allows the laser endpoint beam to be positioned accurately via a user joystick control. -

A laser interferometer measures the change in reflectance of the wafer surface during etching or deposition, by focussing a laser spot onto the wafer and measuring the intensity of the reflected laser light. The laser interferometer camera also provides a TV image of the wafer surface to allow precise positioning of the laser spot onto the correct region. 

The etch rate can be calculated by monitoring ripples in the laser signal due to interference effects within the thin film, allowing the etch to be stopped at a certain depth within the layer. Interfaces between layers can also be detected, as this typically results in an abrupt change in reflectance. 

Laser interferometry typically requires user intervention to position the spot before each run (unless a specific region of the wafer is dedicated for laser endpointing).

Benefits of Laser Endpoint Detector Upgrade

  • Enables etch depth monitoring and endpointing
  • Allows ‘etch-to-depth’ within a layer
  • Precise etch depth control within multi-layer structures
  • Allows endpointing on small samples or those that do not provide a strong OES endpoint
wafer for laser endpointing

Laser Endpoint Detector Upgrade Suitability

Upgrade Available on
Horiba 670nm PlasmaPro 100, PlasmaPro 80
Intellemetrics 670nm PlasmaPro 100
Intellemetrics 980nm PlasmaPro 100

Laser Endpoint Detector Upgrade Process

Most endpoint detection upgrade installations are typically completed within two days, including travel and introductory training on operating an endpoint detector.


For pricing, a free consultation, and more information on laser end point detectors, please contact your local customer service sales team.

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