Low CTE glass with high UV transmittance and light fastness

Abstract

The present invention provides a low CTE glass with high UV transmittance and high light fastness, comprising a composition free of alkali metal oxides: 50‑75 mol% SiO 2 , 3‑20 mol% Al 2 o 3 , 5‑20 mol% of B 2 o 3 , 0-15 mol % of MgO, 0-15 mol % of CaO, 0-15 mol % of SrO and 0-15 mol % of BaO, wherein MgO+CaO+SrO+BaO equals 3 to 25 mol %, and The average number of non-bridging oxygens (NBOs) per polyhedron is equal to or greater than -0.08 or equal to or less than -0.38. In another aspect, the present invention optionally provides a composition free of alkaline earth metal oxides: 75-85 mole % SiO 2 , 0‑7 mol% Al 2 o 3 , 8‑15 mol% of B 2 o 3 , 0‑8 mol% Na 2 O, 0-5 mol% K 2 O, wherein the non-bridging oxygen (NBO) is preferably equal to or greater than -0.25 and equal to or less than -0.10. The present invention also provides a glass carrier wafer with high UV transmittance at a wavelength of 248 nm and / or 308 nm, good light fastness, long cycle life and reduced processing costs and use thereof .

Description

technical field [0001] The present invention relates to a low CTE glass for glass carrier wafers having high UV transmittance and light fastness. The invention also relates to a glass carrier wafer made of said low CTE glass and its use as a carrier wafer in the processing of silicon substrates. Background technique [0002] Thinning of silicon substrates to meet the continuing demand for size reduction of, for example, integrated circuits has become a common process in the semiconductor industry. Silicon carrier wafers have been widely used as mechanical carriers for thinning and backgrinding of silicon substrates to facilitate handling of fragile thinned substrates. The silicon substrate is thus typically bonded to the carrier wafer by an adhesive. Depending on the adhesive, debonding of the silicon substrate from the carrier wafer after processing can be achieved, for example, by solvent release or thermal release. [0003] Glass has been used as a carrier wafer materi...

AI Technical Summary

Problems solved by technology

However, the borosilicate glasses disclosed in these documents are not suitable for use as carrier glass wafers for backgrinding and thinning of silicon for several reasons.

For example, one issue of US 5,547,904 A (Short AG) is that Li 2 O is used in borosilicate glass, which is not preferred in the semiconductor industry because the silicon substrate may be contaminated with lithium ions

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