Inline 100% Surface Inspection of VCR-Sealing Surfaces for UHP Semiconductor appliances
- Andrej Sendrowski
- Mar 19
- 3 min read
Updated: Mar 20
In the era of “ultra-high purity” standards in the semiconductor industry, ensuring leak-tightness of VCR sealing interfaces is of critical importance.
Due to the increasing storage density required for AI applications and modern high-bandwidth memory technologies, ever deeper structures must be created on wafers.
To achieve this, major memory manufacturers are increasingly using more aggressive and corrosive process gases—and doing so more frequently.
Scratches on the sealing surface can serve as entry points for corrosion.
This can not only lead to equipment downtime (worst case), but even very minor damage can result in yield losses due to the resulting corrosion (particles in the process).
This explains why extremely high surface quality is required in the semiconductor industry (SEMI F19 UHP grade and, in some cases, even beyond).
Most VCR sealing surfaces, across different standards, are typically manufactured from
316L / 1.4404 stainless steel and are finished by precision turning and/or electropolishing, featuring toroidal or conical geometries.
A non-destructive, inline-capable inspection of the sealing surface quality is the solution to this problem. However, the boundary conditions for such inspection — such as:
highly reflective and glossy surfaces
complex geometries (conical-concave, conical-convex, toroidal)
very small components (<10 mm diameter)
surface defects <10 µm
—pose more than significant challenges for vision-based systems.
Several 3D imaging technologies currently available on the market cannot be used, such as laser triangulation or pattern projection, as they do not generate usable data on reflective surfaces.
Conventional machine vision techniques, such as dark-field imaging and polarization, are also not feasible due to the component geometry.
To overcome these limitations, we present the solution:
MacroTrax - Dome
The MacroTrax Dome utilizes a hybrid technology combining shape-from-shading and deflectometry to enable surface inspection across the entire relevant component geometry.
This allows for the inspection of surfaces with inclinations of up to 40° relative to the horizontal; under suitable conditions, steeper angles are also possible.
With a diameter of 150 mm and a height of 230 mm, and without the need for additional ambient light shielding, the system is compact and can be easily integrated into and retrofitted onto production and inspection systems.
Three different image sensors are available, currently offering two magnification levels (0.8× and 1.0×).
MacroTrax-535 | MacroTrax-550 | MacroTrax-2025 (in Development) | ||||
Imagesensor | 2432x 2040 @ 3,45µm | 2432 x 2040 @ 5µm | 5104 x 4092 @ 2,5µm | |||
Cycletime | <200ms | <200ms | <350ms | |||
Variant: | 0,8x | 1,0x | 0,8x | 1,0x | 0,8x | 1,0x |
Field of View (mm) | 10,5x8,80 | 8,40x7,04 | 15,20x12,8 | 12,1x10,2 | 15,9x12,8 | 12,8x10,2 |
Depth of Field (mm) | ≈0,6 | ≈0,5 | ≈0,8 | ≈0,7 | ≈0,5 | ≈0,4 |
Resolution ( µm/px ) | 4,3125 | 3,45 | 6,25 | 5,0 | 3,125 | 2,5 |
With this turnkey solution, the inspection of complex components is no longer a challenge. The system generates at least three different images for evaluation, enabling independent inspection of different surface areas.
The three primary image types are:
coaxial
diffuse
hybrid deflectometry
Additional image types can also be generated if required.
The diffuse image, despite its high quality, is often insufficient for detecting scratches. To make these defects visible and analyzable, the hybrid deflectometry image is used.
The raw images of this sample part are available here for review and evaluation.
The system is already successfully in use with renowned german manufacturers of UHP-VCR components.
Defect evaluation and correct categorization are performed without the use of AI, although AI can be optionally employed if requested.
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