How Optical Dimension Measurement Equipment Precisely Controls Flatness and Height Difference

Ceramic materials – with insulation, high-temperature resistance, and thermal conductivity – are essential for semiconductor packaging, power devices, and wafer carriers. Circular ceramic spacers, package substrates, and wafer trays are frequently inspected on production lines. These parts are thin, have wide diameter ranges, and are prone to warpage, local depressions, and uneven step heights after sintering. They also require 2D dimensional checks of inner/outer diameters, positioning slots, and through-holes. Traditional equipment cannot measure planar contours and 3D height parameters simultaneously.

Sinowon, with over a decade of experience in optical dimension measurement, offers a fully automatic Vision Measuring Machine (OMM) equipped with a line laser scanning module. Specifically programmed for semiconductor ceramic workpieces, it completes 2D contour dimensions, full-field flatness, multi-point height, step height, and thickness inspection in a single run – providing a stable, efficient, and non-destructive solution for high-volume production.

I. Core Inspection Requirements for Semiconductor Ceramics

1. 2D Planar Optical Dimension Measurement
Circular spacers and package substrates require outer diameter, inner hole diameter, concentricity, slot length/width, through-hole diameter, hole pitch, edge chamfer, parallelism, and other planar dimensions. The matte and highly reflective nature of ceramics often causes edge blurring and offset in ordinary vision systems, compromising accuracy.

2. 3D Topography Inspection (Industry Difficulty)

• Flatness: ceramic sintering and cooling can cause overall warpage or local depressions. Single-point measurement cannot reflect full-surface flatness; poor flatness leads to assembly gaps or package leaks – fatal defects.
• Step height / full-field thickness: multi-layer composite substrates have layer stack height differences; wafer spacer thickness uniformity directly affects wafer adsorption stability, with height tolerances often within ±1 μm.
• Local protrusion/depression height differences: micro bumps or pits from firing can cause chip damage if height differences exceed tolerances – difficult to cover fully with traditional height gauges.

II. Sinowon OMM Measurement Capabilities for Ceramics

1. Vision Module – Stable Planar Dimension Acquisition
Equipped with a 5-megapixel telecentric lens and 4-channel adjustable ring light + coaxial illumination, the system uses optimized algorithms for reflective ceramics to reduce noise and capture fine edges clearly. After importing CAD drawings, the software automatically recognizes circles, slots, and through-holes, planning measurement paths without manual point-by-point operation. Measurable parameters include diameters, concentricity, slot dimensions, hole pitch, chamfer, parallelism, perpendicularity, profile tolerance, and gaps – accuracy reaching ±0.8 μm, fully matching ceramic micron tolerances. For circular ceramic spacers, the system automatically locates the center and completes outer diameter, through-hole, and concentricity in one click.

2. Line Laser 3D Scanning – Full-Field Flatness, Height, Thickness
Unlike single-point height gauges, line laser scanning uses continuous linear scanning with wide lateral coverage. The servo stage moves the workpiece at uniform speed, capturing millions of 3D coordinate points across the entire surface. The software generates a 3D color topography map to intuitively distinguish warpage, depressions, and protrusions:

• Full-field flatness: least-squares plane fitting from full scan data, outputting overall flatness value and marking out-of-tolerance areas with coordinates.
• Multi-point height/thickness: user-defined hundreds of points, batch output of thickness and height values, automatic calculation of max/min differences.
• Step height: automatic recognition of layer steps on composite substrates with precise layer-to-layer measurement.
• Warpage analysis: for large wafer trays, automatic calculation of height differences at four edges and center, quantifying overall warpage.

III. Three Core Advantages over Traditional Methods

Advantage 1 – Non-destructive, eliminating chipping and scratches
Ceramic is brittle; contact gauges apply pressure causing edge chipping and surface scratches. Semiconductor ceramic parts are expensive, and batch scrap costs remain high. This system uses only optical non-contact measurement – no hard probe touches the surface. Both sintered semi-finished and finished products can be inspected, significantly reducing scrap and saving material costs.

Advantage 2 – 2D+3D integration reduces equipment and floor space
Traditional lines require separate vision measuring machines, laser height gauges, and dial indicators – three machines, three operators, higher costs. Sinowon`s hybrid OMM integrates both in one unit, completing planar and 3D inspection simultaneously. One operator, 50% less floor space, and reduced procurement, maintenance, and labor costs.

Advantage 3 – Fully automatic batch inspection with data archiving, ready for digital factories
Semiconductor production runs are large, requiring complete traceability. The system features a servo gantry with quick-change fixtures. Circular spacers can be placed on adjustable supports for rapid positioning. One-click batch program completes full 2D+3D inspection in ~30 seconds per part. Reports (PDF) are automatically generated with dimensions, flatness maps, and height data – MES integration enables real-time cloud upload and permanent batch traceability, meeting stringent quality audit requirements.

IV. Typical Applications and Case Examples

The line laser OMM is already in use at multiple ceramic component manufacturers, inspecting: power device ceramic package substrates, SiC wafer carrier spacers, IGBT thermal rings, chip package isolation spacers, and wafer positioning discs. After adoption, inspection efficiency increased by 280%, flatness miss-rate dropped to zero, and scratch/scrap losses decreased by 92%, with significant improvement in digital quality control.

V. Selection Guide

For ceramic spacers and medium-sized substrates, choose Sinowon`s gantry OMM with a large transparent worktable and dedicated circular support tooling. For micro lead frames and small terminals, select the benchtop hybrid model. Both support custom semiconductor inspection templates – start programs immediately with minimal operator training.

For customized ceramic inspection solutions, visit www.sinowon.com.