CASE STUDY · Wafer-Level Glass Processing

Glass Wafer Processing Case Study

For glass discs and wafer substrates, we control material, diameter, thickness, edges, two-sided condition, cleaning and packaging together.

Project Overview

The complete route from material confirmation to finished-part delivery

Glass wafers usually serve sensing, microelectronics, optics and packaging projects. Beyond diameter and thickness, attention should go to flatness, thickness variation, edge profile, two-sided appearance, orientation marking and clean packaging, with acceptance defined together with downstream coating, bonding or lithography processes.

Typical materials: Fused quartz, BOROFLOAT® 33, alkali-free glass and others
Main operations: Disc forming, lapping and polishing, edge processing, cleaning
Control focus: Diameter, thickness, TTV, edges and two-sided appearance
Applications: MEMS, sensors, microelectronics and optical packaging

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ENGINEERING GUIDE

Derive glass wafer specifications from the downstream process

A glass wafer is not finished by simply cutting a flat plate into a circle. Downstream lithography, bonding, coating and equipment handling each map to TTV, Bow/Warp, edge, locating features, surface and particle requirements, all of which must be confirmed together before material is purchased.

Applications

Where it can be used

MEMS pressure, inertial, acoustic and environmental sensors
Glass-silicon anodic bonding, wafer-level packaging and transparent lids
Microfluidic chips, channel lids and inspection windows
Micro-optical arrays, wafer-level lenses, filtering and optoelectronic devices
Temporary carriers, thin-plate supports, micro-hole and hole-array substrates

Material Selection Logic

Why glass

Glass combines transparency, electrical insulation, chemical stability and adjustable thermal expansion. Different material systems match silicon bonding, low-alkali thin films, UV optics, high-temperature or low-CTE processes respectively.

Material Selection

Common materials and their applications

Material	Applications	Selection focus
PYREX® Micro-Electro	MEMS, anodic bonding and glass-silicon packaging	CTE 3.43 × 10⁻⁶/°C（0–300°C）
BOROFLOAT® 33	General wafers, sensing, microfluidics and optical packaging	CTE 3.25 × 10⁻⁶ K⁻¹, with a wide range of available specifications
EAGLE XG®	Low-alkali, thin-film, display and thin wafers	Low total alkali, high strain point and good pristine surface quality
Fused quartz / JGS1	UV, laser, high-temperature, low-CTE and high-purity applications	Confirm the spectrum, hydroxyl, impurities and internal quality

Typical Parameters

Common enquiry parameters

Item	Common starting points or wording	Engineering notes
Diameter	Commonly 100, 150, 200, 300 mm	Compatible with equipment, chucks, cassettes and layout
Thickness	Commonly 0.20, 0.30, 0.40, 0.50, 0.70, 0.85, 1.10 mm	Stock and tolerances differ by material
TTV	Standard discussion from ≤10-25 μm; precision bonding can be evaluated to ≤1-5 μm	PYREX® wafers can be evaluated to ≤1 μm
Bow/Warp	Defined individually by equipment and process	State the measurement face, support and edge exclusion
Surface roughness	Coating/lithography/bonding faces are defined by Ra or process compatibility	The published Ra of the EAGLE XG® pristine surface is ≤10 Å
Edge	Chamfered, rounded or specified profile	State front/back, edge exclusion and maximum chipping
Hole arrays	Hole diameter, pitch, taper, inlet/outlet chipping and position tolerance	Laser processes must be validated against material thickness and samples

Structure and Function

What it usually needs to look like

Available as standard round wafers, discs with Flat/Notch, rectangular carriers, wafers with hole arrays or windows, double-sided polished wafers, single-side functional wafers and bonding lid wafers.

As substrates for thin films, lithography, bonding and packaging
As transparent lids, carriers and insulating layers
Carrying micro-holes, channels or micro-optical structures
Provide a stable geometric reference for equipment handling and processing

Performance Requirements

Performance items recommended for confirmation

Material CTE, strain point, dielectric and spectral matching
Low TTV, controlled Bow/Warp and stable thickness
Low roughness, low particles and controlled surface defects
Edge profile, locating features and equipment compatibility
Lot material documents, inspection records and clean packaging

Preparing Your Enquiry

Please provide in the drawing or enquiry

Material grade, wafer diameter, thickness, TTV, Bow/Warp, Flat/Notch, edge profile, A/B faces, surface grade, hole array drawing, edge exclusion, downstream lithography/bonding/coating conditions, cleanliness requirements, quantity and packaging.

The parameters above are for preliminary material and process selection and do not constitute a uniform guarantee for all dimensions, thicknesses and materials. Final specifications, measurement methods and delivery standards are governed by the drawing, samples and order documents confirmed by both parties.

Wafer specification confirmation

Confirm material, diameter, thickness, flat or notch, effective area and downstream processes.

Glass wafer processing and material preparation

Disc and edge forming

Establish the circular outline and edge structure, reducing edge chipping and later handling risk.

Lapping and double-sided processing

Lapping or double-sided polishing is carried out according to thickness, parallelism and surface requirements.

Clean inspection and packaging

Check dimensions, edges, two-sided appearance and cleanliness, and package according to handling and downstream process requirements.

Start material selection and processing requirements from the same drawing

Send the drawing and key acceptance items and we will assess the project together with the material and process route.

Email Your Drawings Contact the Engineering Team