An alumina wafer carrier is a high-purity ceramic fixture—made from 99.7–99.9% alumina—designed to hold and support silicon, sapphire, and compound semiconductor wafers during processes such as diffusion, oxidation, wet cleaning, RIE and CMP. Its stable, inert structure protects wafers from deformation, particle contamination and metallic impurities while maintaining flatness through high-temperature and chemical environments.
Alumina Wafer Carrier Benefits
- Designed for high-temperature wafer processing
Alumina wafer carriers tolerate furnace and diffusion steps up to roughly 1700–1750 °C, allowing repeated thermal cycling without the softening or deformation seen in many polymer-based carriers.
- Flatness and stability for polishing and lapping
Polished alumina polishing plates and carrier plates are specified with flatness down to the micrometer and even sub-micrometer level across large diameters, supporting uniform material removal in CMP and lapping.
- Low contamination for higher wafer yield
Industry studies show that particulate contamination can contribute to more than 60% of wafer yield loss, so robust, low-particle carriers are critical. High-purity alumina carriers reduce organic outgassing compared with polymer boxes and contribute less micro-debris than many metal fixtures.
- Chemically resistant in aggressive chemistries
Alumina carrier plates withstand common wet-cleaning chemistries and CMP slurries used in wafer cleaning and polishing processes, where they are exposed to oxidizers and abrasive suspensions over long periods.
- Flexible geometries for different tools
Commercial alumina polishing plates and carrier plates are available as discs, rings and complex grooved forms up to several hundred millimeters in diameter, making it practical to match the fixture design to the diffusion furnace, CMP tool or cleaning bench.
Alumina Ceramic Wafer Carrier Properties
| Property |
96% Alumina |
99% Alumina |
99.5% Alumina |
99.7% Alumina |
99.8–99.9% Alumina |
| Density (g/cm³) |
3.70–3.75 |
3.83–3.88 |
3.88–3.90 |
3.90–3.93 |
3.90–3.95 |
| Hardness (GPa, typical) |
Approx. 14–15 |
Approx. 16–17 |
Approx. 15–18 |
Approx. 15–18 |
Approx. 15–18 |
| Flexural Strength (MPa, typical) |
Approx. 260–300 |
Approx. 300–350 |
Approx. 350–380 |
Confirm by grade |
Confirm by supplier data |
| Typical Maximum Use Temperature (no load) |
1500–1600°C |
1650–1700°C |
Up to 1750°C |
1750–1760°C |
Confirm by supplier data |
| Volume Resistivity |
High; electrically insulating |
High; electrically insulating |
High; electrically insulating |
High; electrically insulating |
High; electrically insulating |
Alumina Wafer Carrier Specifications
|
Item No. |
Outer Dia（mm） |
Height（mm） |
Purity（%） |
|
AT-BDT-B001 |
240 |
15 |
99.5 |
|
AT-BDT-B002 |
240 |
25 |
99.6 |
|
AT-BDT-B003 |
245 |
25 |
99.6 |
|
AT-BDT-B004 |
263 |
25 |
99.6 |
|
AT-BDT-B005 |
300 |
20 |
99.6 |
|
AT-BDT-B006 |
310 |
20 |
99.6 |
|
AT-BDT-B007 |
350 |
15 |
99.5 |
|
AT-BDT-B008 |
355 |
16 |
99.6 |
|
AT-BDT-B009 |
360 |
16 |
99.6 |
|
AT-BDT-B010 |
400 |
15 |
99 |
Alumina Ceramic Wafer Carrier Packaging
- Carriers are first wrapped in clean, lint-free protective material to limit particle generation during transport, consistent with practices used for ceramic and polished wafer plates.
Where Alumina Wafer Carriers Are Used
Alumina wafer carriers are used when wafer support, dimensional stability, wear resistance and equipment compatibility are critical. ADCERAX custom-machines carrier disks, slot boats, edge rings, support fixtures and loader-arm components around the wafer size, contact strategy, process conditions and tool interface.
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Wafer Handling and Automation
Carrier disks, edge rings and ceramic loader-arm components support and locate wafers during transfer, loading, unloading and robotic handling. Contact surfaces, pockets, alignment features and clearances can be designed to help reduce backside particles, contact marks, wafer movement and edge-damage risks.
Custom options include wafer pockets, locating pins, slots, mounting holes, vacuum features and equipment-interface details.
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Diffusion, Oxidation and LPCVD Furnaces
Alumina wafer boats and slot carriers can support multiple wafers through grade-dependent, high-temperature furnace processes. Compared with polymer carriers, alumina provides better dimensional stability in thermal environments where softening, outgassing or deformation may be a concern.
Slot count, pitch, loading direction, carrier mass and support geometry can be adjusted to match the furnace layout and wafer-spacing requirements. Final material grade and temperature suitability are confirmed from the process profile and drawing.
-
Inspection, Metrology and Vacuum Support
Flat carrier disks, support rings and custom fixtures provide defined contact points and positioning references for wafer inspection, measurement and vacuum-handling equipment. Critical datums, mounting interfaces, pockets and surface requirements can be machined to suit the inspection method.
Ground or polished functional surfaces are available where controlled contact, positioning consistency or finished-part flatness is required. Specifications must be confirmed for each design.
-
CMP, Lapping and Wafer Cleaning
Alumina carrier plates, polishing disks and support fixtures can be reviewed for CMP, precision lapping and wet-cleaning applications. Their hard, wear-resistant surfaces make alumina a useful candidate where the carrier is exposed to repeated contact, abrasive slurry or cleaning cycles.
Pocket geometry, drainage features, contact areas, surface finish and chemical exposure should be defined before material and manufacturing requirements are confirmed.
-
Photovoltaic, LED and Compound-Semiconductor Processing
Custom alumina carriers can also support wafers or fragile substrates in photovoltaic diffusion, LED processing and selected compound-semiconductor equipment. Disk, boat and fixture geometries can be adapted for different wafer formats, loading systems and thermal-process layouts.
For non-standard wafers or fragile substrates, ADCERAX can review custom support areas, edge clearances, chip recesses and handling features from a drawing, photograph or sample.
Alumina Wafer Carrier Handling, Integration and Maintenance Guidelines
The following are general handling considerations. Final operating, cleaning and inspection procedures must be confirmed against the carrier drawing, equipment manual and process requirements.
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Before Installation
1. Confirm the wafer size, carrier form, pocket or slot layout, contact areas and equipment interface against the approved drawing.
2. Check critical dimensions, mounting features and loading clearances before introducing the carrier into the tool.
3. Inspect the carrier for visible chips, cracks, damaged pockets or surface defects that may affect wafer contact or positioning.
4. For a new or replacement design, complete a trial installation and process validation with suitable test wafers before production use.
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Tool Integration and Operation
1. Load and unload wafers according to the equipment procedure, avoiding impact, forced insertion and unnecessary sliding across contact surfaces.
2. Follow the tool manufacturer’s requirements for loading direction, alignment, temperature profile, atmosphere, vacuum and process cycle.
3. Confirm that heating and cooling rates are suitable for the selected alumina grade and carrier geometry.
4. Do not assume that a replacement carrier is a direct drop-in part until the dimensions, contact points and equipment interface have been validated.
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Cleaning Process Review
1. Define the cleaning chemistry, concentration, temperature, exposure time, rinse method and drying procedure for the specific process.
2. Confirm compatibility between the alumina grade, surface finish and cleaning method before routine use.
3. If ultrasonic cleaning is required, specify the solution, frequency, power and duration to avoid damaging thin sections, slots or polished surfaces.
4. Rinse and dry the carrier according to the customer’s documented cleanliness and particle-control requirements.
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Storage and Handling
1. Store carriers in a clean, dry and protected location when they are not in use.
2. Separate individual carriers with suitable protective material or dedicated racks to prevent ceramic-to-ceramic impact.
3. Avoid direct contact with hard metal tools, sharp edges or contaminated work surfaces.
4. Define any special handling, labeling and packaging requirements during the engineering review.
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Inspection and Replacement Criteria
1. Establish inspection intervals based on process cycles, wafer-contact conditions and the customer’s quality requirements.
2. Check slots, pockets, support points, edges, mounting features and polished surfaces for wear, chips, cracks or residue.
3. Remove and quarantine a carrier if damage could affect wafer positioning, contact conditions or equipment clearance.
4. Confirm acceptance and replacement criteria from the approved drawing and inspection plan rather than relying only on visual judgment.
For an engineering review, provide the wafer size, carrier drawing or photographs, contact areas, equipment interface, operating temperature, atmosphere or vacuum, cleaning process and required quantity.
