Monitoring apparatus and method for in-situ measurement of wafer thicknesses for monitoring the thinning of semiconductor wafers and thinning apparatus comprising a wet etching apparatus and a monitoring apparatus

US8716039B2 · kind B2 · utility

Assignee

• PRECITEC OPTRONIK GMBH · DE

Inventors

• Claus Dusemund · Singapore, SG
• Martin Schoenleber · Aschaffenburg, DE
• Berthold Michelt · Wiesbaden, DE
• Christoph Dietz · Obertshausen, DE

Key dates

• Filing date: Jan 10, 2011
• Grant date: May 6, 2014
• Expiry date: Jan 10, 2031

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L21/67023
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

According to the invention, a monitoring device (12) is created for monitoring a thinning of at least one semiconductor wafer (4) in a wet etching unit (5), wherein the monitoring device (12) comprises a light source (14), which is designed to emit coherent light of a light wave band for which the semiconductor wafer (4) is optically transparent. The monitoring device (12) further comprises a measuring head (13), which is arranged contact-free with respect to a surface of the semiconductor wafer (4) to be etched, wherein the measuring head (13) is designed to irradiate the semiconductor wafer (4) with the coherent light of the light wave band and to receive radiation (16) reflected by the semiconductor wafer (4). Moreover, the monitoring device (12) comprises a spectrometer (17) and a beam splitter, via which the coherent light of the light wave band is directed to the measuring head (13) and the reflected radiation is directed to the spectrometer (17). The monitoring device (12) further comprises an evaluation unit (18), wherein the evaluation unit (18) is designed to determine a thickness d(t) of the semiconductor wafer (4) from the radiation (16) reflected by the semiconductor w…