Difference between revisions of "Stylus profilometry"
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[[{{PAGENAME}}|{{PAGENAME}} (contact profilometry)]] brings a stylus tip into direct contact with a sample in order to trace the topography of the surface. This technique is often used to measure step heights and feature sizes for samples which have etched patterns on them. | [[{{PAGENAME}}|{{PAGENAME}} (contact profilometry)]] brings a stylus tip into direct contact with a sample in order to trace the topography of the surface. This technique is often used to measure step heights and feature sizes for samples which have etched patterns on them. | ||
| + | |||
| + | ==Equipment== | ||
| + | |||
| + | ===Dektak XT=== | ||
| + | {{main|Dektak XT}} | ||
| + | Latest model Dektak profiler located in the main cleanroom. This tool has a fully automated stage and is capable of 3D mapping and scanning the full diameter of a 150 mm wafer. | ||
| + | ===Dektak 6M=== | ||
| + | {{main|Dektak 6M}} | ||
| + | Older model Dektak profiler located in the ROBIN lab (Wet Chemistry). | ||
| + | |||
| + | <!--===Complete tool list=== | ||
| + | <categorytree mode=pages>{{#var:acronym|{{PAGENAME}}}} equipment</categorytree> | ||
| + | ==See also== | ||
| + | Other related wiki pages | ||
| + | --> | ||
==Method of operation== | ==Method of operation== | ||
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Optional description of materials that can be processed by technology. I think the best example of where this comes in handy would be with LPCVD describing the difference between HTO and LTO. | Optional description of materials that can be processed by technology. I think the best example of where this comes in handy would be with LPCVD describing the difference between HTO and LTO. | ||
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Revision as of 10:56, 10 March 2020
| Stylus profilometry | |
|---|---|
 Stylus image and trace example[1] | |
| Technology Details | |
| Other Names | Contact profilometry |
| Technology | Metrology |
| Equipment | Dektak XT, Dektak 6M |
Stylus profilometry (contact profilometry) brings a stylus tip into direct contact with a sample in order to trace the topography of the surface. This technique is often used to measure step heights and feature sizes for samples which have etched patterns on them.
Contents
Equipment
Dektak XT
Main article: Dektak XT
Latest model Dektak profiler located in the main cleanroom. This tool has a fully automated stage and is capable of 3D mapping and scanning the full diameter of a 150 mm wafer.
Dektak 6M
Main article: Dektak 6M
Older model Dektak profiler located in the ROBIN lab (Wet Chemistry).
Method of operation
- The profilometer brings a small stylus tip into contact with the sample surface. For the stylus profilometers at LNF, we have 25 μm diameter diamond tip styli.
- The tool maintains a constant stylus tip contact force as the stage moves the sample underneath the stylus.
- Deflection of the stylus tip is measured by a sensor head (LVDT - linear variable differential transformer)
- Sample surface heights are then plotted versus lateral position to be analyzed.
Applications
Stylus profilometry is often used for measuring step heights and feature sizes for samples that have been patterned and etched. The physical dimensions of the stylus cause limitations in what can be measured with this method.
- The stylus must be able to physically climb up a step feature's height. Our stylus profilometers are only able to measure step heights up to 150 μm.
- The aspect ratio (feature depth divided by width) can not be greater than ~1. The maximum aspect ratio that can be measured is dependent on the width of trench features. The plot below shows this dependence. At 25um trench width, the aspect ratio of the feature must be less than 0.5.
- For step heights taller than 150 μm or for high aspect ratio features, one of the optical 3D profilers (Zygo or LEXT) need to be used.
Maximum Aspect Ratio vs. Trench Width for 25 μm diameter stylus tip
References
Further reading
https://www.bruker.com/products/surface-analysis/stylus-profilometry.html
