Choose the substrate around the instrument
Optical glass, fused silica or another specified substrate is selected from wavelength, thermal behaviour, thickness, flatness and mounting needs. The material name alone does not define transmission or system stability.
Pattern transfer can use several routes
Diamond ruling, mask exposure and direct laser writing are different ways to create the same functional geometry. The released drawing controls the pattern; the selected route controls practical line edge, bias, registration and repeatability.
- Keep the artwork revision, substrate datum and film side connected through coating, exposure, development and etch.
- If the pattern is illuminated, define whether the required feature is a clear opening, opaque line or reflective mark.
Separate line width, pitch and placement
Line width controls visibility and occlusion. Pitch controls scale or frequency. Pattern placement controls the relationship to the holder, optical axis or coordinate origin. Passing one does not prove the others.
Inspect the active field and the edge condition
Mark the clear aperture, active pattern area, mounting zone and edge exclusion on the drawing. A particle or missing film crossing a functional line can matter more than a larger mark outside the field.
| Quantity | It establishes | It does not establish |
|---|---|---|
| Line width or CD | Feature size at the stated method | Intersection position or installed accuracy |
| Pitch or interval | Relationship between repeated features | Absolute location to the holder |
| Pattern placement | Feature coordinate to a datum | Local line width or visual contrast |
| Optical density or reflectance | Contrast at stated wavelength and geometry | Surface defect or focal-plane error |
Keep optical acceptance separate from installed verification
A component record can report dimensions, pattern position, defects, surface condition and contrast. The assembled instrument adds focus, holder seating, axis alignment, magnification, illumination and observer or detector response.
Define the released drawing package
A DWG should carry 1:1 model-space geometry, units, layer meanings, film-side orientation, focal-plane or mounting datum, revision and active-area limits. A PDF can support visual review but does not replace editable CAD geometry.
Protect the pattern after inspection
Store and handle the patterned surface according to its coating and assembly. Cleaning compatibility, edge handling and packaging should be agreed for the actual film and holder; there is no universal solvent or service-life rule for every reticle.
Tie the measurement record to its reference
A useful dimensional record identifies the drawing revision, measured feature, datum, measurement method and uncertainty. Inspect pitch over several intervals as well as the active span: a correct single interval can coexist with accumulated scale error. Component calibration may be supplied when agreed; installed instrument calibration remains a separate result.
- Document whether a position is measured from a film fiducial, glass edge or mounting datum.
- State the working wavelength and illumination geometry for transmission, optical density or reflectance results.
- Check the functional pattern after coating, etching and any agreed assembly stage rather than using artwork alone as evidence.