1. Summary
High purity synthetic quartz is the input most likely to sit on a critical path in optical lithography, and the numbers around ZTSQ-02 explain why procurement teams are re-examining their source list: 99.99 % SiO2, stress birefringence from ≤2 nm/cm in grade A to ≤10 nm/cm in grade D, no streak in one direction, a 20 kg minimum order that covers NPI builds, 200 metric tons per month of capacity, and 30–45 day delivery on FOB Shanghai terms with L/C, D/A, D/P and T/T accepted. The material is grown from a purified silicon precursor rather than melted from mineral ore, so it carries no ore-derived metal signature — the property that makes deep-ultraviolet transmission possible. It ships as ingots and blocks for photomask substrates, excimer windows, DUV lens blanks and metrology optics, documented to MSDS, RoHS, REACH, ISO, GS, BV and Intertek, in clean sealed bags, master cartons and wooden crates.
2. What Is a Low-OH Natural Quartz Cylinder?
When a purchasing team writes “high purity synthetic quartz” on a requisition, three different things are usually being asked for at once: a chemical specification, an optical specification and a documentation standard. Separating them is the first step toward a purchase order that does not come back.
The chemical specification is the easy part to state and the hardest to verify. Synthetic quartz is amorphous SiO2 grown from a purified precursor — flame hydrolysis of silicon tetrachloride is the industrial standard — and then vitrified. Because the silicon enters as a gas rather than as crushed rock, the residual metal content is set by the precursor's purity and by the cleanliness of the reactor, not by geology. Purity for the ZTSQ-02 family is stated above 99.99 %, and the meaningful question is not the headline figure but which elements remain and at what concentration. Iron and copper absorb in the deep ultraviolet; sodium and lithium migrate; aluminium scatters. A supplier who reports only “99.99 %” without an element-by-element ICP-MS table is telling you half of what you asked.
The optical specification is where the grade letter lives. Stress birefringence is the residual photoelastic response of the glass: light entering a stressed body splits into two orthogonal components that travel at different speeds, accumulating a path difference proportional to stress and thickness. It is quoted in nanometres per centimetre of path, and ZTSQ-02 is graded A ≤2, B ≤5, C ≤5 and D ≤10 nm/cm. Streak — striae — is layered index variation from the deposition process, controlled to no streak in one direction. Transmission is measured across the working band, and at 193 nm it is the figure that separates a lithography substrate from a lab sample.
The documentation standard is what makes the first two auditable: a lot-level certificate carrying birefringence mapping, transmission data, striae statement and trace metals, alongside MSDS, RoHS, REACH, ISO, GS, BV and Intertek compliance. A 20 kg minimum order, 200 metric tons per month of capacity and 30–45 day delivery on FOB Shanghai terms are then simply the commercial envelope around that quality system.
PQ800E / PQ800EH — Key Technical Parameters
| Property |
Value |
Why it matters |
| SiO2 purity |
99.9999 % (6N) |
Metallic contamination budget for wafer processing |
| Density |
2.2 g/cm³ |
Lot consistency and material identification |
| Thermal conductivity (1,000 °C) |
2.28 W/m·K |
Flatter thermal gradients, lower shock stress |
| Coefficient of thermal expansion |
5.5 × 10-7 /°C |
Thermal shock resistance, dimensional stability |
| Softening point |
1,670 °C |
Tube drawing / forming temperature |
| Annealing point |
1,210 °C |
Stress relief after machining |
| Strain point |
1,110 °C |
Practical ceiling for dimensional stability |
| MOQ / Capacity |
50 kg / 2,000 t per month |
Pilot builds through volume ramp |
| Delivery / Terms |
30–45 days, FOB Shanghai |
L/C, D/A, D/P, T/T |
3. Why It Matters: Four Advantages That Change Tool Uptime
Qualifying a second source for optical quartz is slow because the failure modes are silent. A bad lot does not arrive broken; it arrives transparent, dimensionally correct and marginally out of specification, and the damage surfaces months later in a lithography yield report. Four pressures push buyers to look for a better-structured supply relationship.
1. The specification gap between datasheet and lot. Many suppliers quote a grade letter without a measurement method. Birefringence reported as a single spot value at the centre of a blank tells you nothing about the clear aperture your design actually uses. A supplier who maps the distribution and ships the raw data lets incoming inspection become verification instead of sampling. For teams drafting a quartz substrate incoming inspection procedure, that is the difference between a one-day and a one-month release cycle.
2. Small-quantity qualification is the real bottleneck. A 20 kg minimum order changes the shape of the programme. Engineering can pull material for a trial polish, a birefringence map and a transmission scan before the commercial negotiation is finished, so technical and commercial tracks run in parallel. When the minimum is a tonne, the sample waits for the contract, and the contract waits for the sample.
3. Single-source exposure on natural quartz. Semiconductor-grade natural quartz depends on a handful of ore bodies with the right chemistry, and that chain is not something a fab controls. Synthetic capacity scales with reactors and precursor supply instead, and 200 metric tons per month is enough to support a qualified second source without competing for allocation. For an optical quartz supplier risk assessment, that independence is the finding that matters.
4. Total cost, not price per kilo. Synthetic material costs more per kilogram than natural quartz and less per good die. One absorbed 193 nm lot, one rejected photomask blank, one scrapped projection element — each wipes out the saving from a cheaper substrate many times over. Buyers who benchmark high purity synthetic quartz price per kg against scrap rate and inspection hours almost always move to the tighter grade.
Add the practical items: 30–45 day delivery from FOB Shanghai, four payment instruments (L/C, D/A, D/P, T/T) covering trial order through annual agreement, and a packaging sequence — clean plastic sealing bag, master carton, wooden crate — that survives international freight without turning a polished surface into a handled one. These are not differentiators on their own; they are what makes the technical differentiator usable.
4. How It Works in Real Production: From Cylinder to Qualified Component
Moving to ZTSQ-02 is a six-phase programme, and the order matters more than the schedule. What follows is the sequence our engineering team runs with new optical customers.
Phase 1 — Write the requirement as a measurement
Convert the optical design into four testable statements: birefringence grade and the aperture over which it must hold; striae orientation; transmission over a named wavelength band; and trace-metal limits by element. Add the mechanical items — thickness, flatness, surface quality, edge condition. A requirement phrased as “high purity” will be met by any supplier; a requirement phrased as “≤2 nm/cm maximum over a 150 mm aperture, 193 nm transmission measured per lot” cannot be.
Phase 2 — Take a 20 kg sample and test it yourself
The 20 kg minimum exists for this phase. Cut and polish a witness part, then run polarimeter mapping across the full aperture; spectrophotometer transmission at 193 and 248 nm against your own baseline; shadowgraph inspection in the orientation of use; and ICP-MS for iron, copper, sodium, potassium and aluminium. Compare the results to the lot certificate. You are testing the documentation culture as much as the glass.
Phase 3 — Prove the process, not just the blank
Grinding and polishing can add stress. Run the full sequence — coarse grind, stress relief, fine grind, lap, polish — on sample blanks and re-measure birefringence at the end. If the delivered value drifts above grade, the fix is a process step, not a new supplier, and it is much cheaper to find that out in phase three than in production.
Phase 4 — Freeze the purchase specification
Write down grade letter, aperture definition, transmission band, striae statement, trace-metal limits, blank dimensions, annealing and stress-relief requirements, cleaning protocol, packaging (clean sealed bag, master carton, wooden crate) and the certificate contents. This document is what makes a second source repeatable rather than lucky.
Phase 5 — Build the replenishment model
With 200 metric tons per month of capacity and 30–45 day delivery, the model is a rolling forecast plus a buffer sized to the polishing and inspection cycle. Urgent lots move by air in the standard pack; planned volume goes by sea. FOB Shanghai keeps freight control with the buyer, and L/C, D/A, D/P or T/T can each be matched to the order size.
Phase 6 — Extend across the optical bill of materials
Once qualified for photomask blanks, the same platform covers excimer laser windows at 193 and 248 nm, DUV projection lens blanks, wafer inspection and metrology flats, and reference substrates where low birefringence is the specification. Each extension reuses phase two and three data, which is where the programme pays for itself: one material qualification covering several optical part numbers.
Send the drawing, working wavelength, aperture and grade requirement and we will return a blank size, a material recommendation and a quotation — typically without a clarification round, because the specification already contains everything the quotation needs. From sample request to qualified part, the realistic envelope is one sample cycle plus one process validation cycle, and the 30–45 day delivery window runs inside both.
5. FAQ
Q1. What defines high purity synthetic quartz in a purchase order?
Three things: SiO2 content above 99.99 % with trace metals reported element by element by ICP-MS; a stress birefringence grade with a stated measurement method and aperture; and a lot-level certificate covering transmission and striae. A purity figure alone does not define the material for optical use, and a grade letter without a stated method does not define birefringence.
Q2. Why is the 20 kg minimum order important for qualification?
It lets engineering pull material for a trial polish, birefringence mapping and transmission testing before commercial terms are settled. Technical and commercial tracks then run in parallel instead of sequentially. With a one-tonne minimum, the sample waits for the contract and the qualification timeline stretches by months. Twenty kilograms is enough for a witness part and a full measurement set.
Q3. Which birefringence grade should we specify?
Grade A at ≤2 nm/cm for 193 nm photomask substrates and projection lens elements where polarisation is controlled. Grade B or C at ≤5 nm/cm suits 248 nm excimer windows and many illumination-path parts. Grade D at ≤10 nm/cm is adequate for reference flats and non-imaging optics. The grade letter, not the purity figure, prices the part.
Q4. What lead time and payment terms apply?
Delivery is 30–45 days on FOB Shanghai terms, against 200 metric tons per month of capacity. L/C, D/A, D/P and T/T are all accepted, so a trial sample order and an annual agreement can use different instruments. Standard packaging is a clean sealing bag, master carton and wooden crate, which survives air freight and sea freight without extra handling of polished surfaces.
Q5. How do we verify a lot without a full optical lab?
Ask for the raw measurement data, not the pass stamp: birefringence distribution across the aperture, transmission values with the instrument referenced, striae orientation, and the ICP-MS element table. Then verify on a witness part with your own polarimeter and spectrophotometer. Two independent measurements on the same lot is a workable audit trail.
Q6. Can synthetic quartz replace natural quartz in furnace parts?
Usually not on cost, and often not on geometry. Natural quartz wins for large furnace tubes and boats where ppm-level metals are tolerable and volume matters. Synthetic quartz is specified where absorption, birefringence and homogeneity decide performance: photomask blanks, DUV optics, excimer windows and metrology flats. The two are complementary, not interchangeable.
6. Conclusion
High purity synthetic quartz is a measurement problem disguised as a purchasing decision. Fix the birefringence grade, the aperture, the wavelength band and the trace-metal limits, and the rest of the programme — sampling, qualification, replenishment — becomes routine. Leave them vague and every lot becomes a negotiation, with the scrap cost sitting on the buyer's side of the table.
The supply model matters just as much as the specification: a small entry quantity to test with, real capacity behind the qualification, and a delivery window short enough to plan around.
ZTSQ-02 is built to be specified that way: 99.99 % SiO2, grades A through D from 2 nm/cm, no streak in one direction, a 20 kg entry point, 200 metric tons of monthly capacity and 30–45 day delivery from FOB Shanghai. Next step: request the ZTSQ-02 specification pack and a 20 kg sample quotation, or send your optical drawing and wavelength for a grade recommendation within two business days.
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