Low CTE glass with high UV transmittance and light fastness

Abstract

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

Description

Technical field [0001] The present invention relates to a low CTE glass for use as a glass carrier wafer with 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 silicon substrates to meet the continued 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 back grinding of silicon substrates to facilitate handling of fragile thinned substrates. The silicon substrate is thereby bonded to the carrier wafer, usually with 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...

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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