ROC and its material partner co-developed a 12-inch, 10 mm specialty glass wafer for lithography equipment. ROC’s precision grinding and polishing process achieved surface figure (PV) ≤ 1.0 μm, parallelism ≤ 1.8 μm, surface roughness Ra ≤ 0.18 nm and concentricity tolerance ±0.030 mm.
Specialty glass wafers used in photolithography equipment must meet demanding requirements for material purity, optical homogeneity, thermal stability and dimensional accuracy. According to the client, the critical material for this application had previously been sourced from a single supplier, creating risks related to material availability, lead times and supply continuity.
Three years ago, ROC began a joint development program with a material manufacturer for 12-inch specialty glass wafers used in photolithography equipment. The material manufacturer was responsible for glass melting, formulation and material-property development, while ROC processed the material into high-precision polished glass wafers and conducted systematic testing and process qualification.
Following development and qualification, the client established an additional qualified supply source for 10 mm-thick specialty glass wafers.
The client had previously relied on a single supplier for this specialty glass. Although initial demand was limited, single-source dependence created a material-supply risk and left domestic customers without a qualified alternative.
The product needed to meet several demanding specifications simultaneously at a 12-inch diameter:
Meeting these specifications simultaneously on a 12-inch, 10 mm-thick wafer required dedicated precision grinding and polishing processes, suitable equipment and rigorous process control.
ROC worked closely with the material manufacturer throughout development. The material manufacturer was responsible for glass melting and formulation development, while ROC processed different material batches into polished glass wafers, conducted full-process grinding and polishing trials, and provided feedback on machinability, surface-figure retention and surface quality.
The results enabled both parties to iteratively optimize the glass formulation and its processing performance.
The program also addressed the client’s dependence on a single material source. As customer demand increased, the jointly developed product progressed to end-customer qualification.
To address the 12-inch diameter, 10 mm thickness and demanding precision requirements, ROC developed a dedicated multi-stage polishing process and optimized the associated polishing consumables for the material and target specifications.
The process focused on four critical challenges:
Achieved results:
| Parameter | Required specification | Achieved by ROC |
| Product diameter | 12 inches | 12 inches |
| Product thickness | 10 mm | 10 mm |
| Surface figure (PV) | ≤ 1.8 μm | ≤ 1.0 μm |
| Parallelism | ≤ 2 μm | ≤ 1.8 μm |
| Surface roughness | Ra ≤ 0.2 nm | Ra ≤ 0.18 nm |
| Concentricity tolerance | ≤ ±0.036 mm | ≤ ±0.030 mm |
The specialty glass wafer jointly developed by ROC and the material manufacturer qualified as an alternative to the incumbent material for the evaluated application, strengthening supply-chain resilience.
The qualified alternative reduced dependence on a single material source and lowered the associated risk of supply disruption.
For a 12-inch, 10 mm-thick wafer, ROC achieved the following specifications in combination:
These results demonstrate ROC’s capabilities in precision grinding and polishing for technically demanding specialty glass wafers.
The product underwent qualification by multiple industry customers, with no issues reported during the qualification period. It is now supplied to several customers, providing initial evidence of repeatability and production consistency.
ROC tested different material batches and shared data on machinability, surface figure and polishing performance, helping the material manufacturer refine the glass formulation.
The two parties followed an iterative process of material preparation, sample processing, measurement, feedback and optimization.
The 12-inch, 10 mm-thick wafer achieved PV ≤ 1.0 μm, parallelism ≤ 1.8 μm, Ra ≤ 0.18 nm and concentricity within ±0.030 mm.
The collaboration established an additional qualified supply route and reduced dependence on a single material source.
Yes. ROC can support material evaluation, sample processing, measurement feedback and process qualification for other specialty glass projects.
