Method for manufacturing a combination of a pressure sensor and an electrochemical sensor

US5918110A · kind A · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventors

• Klaus Abraham-Fuchs · Erlangen, DE
• Walter Gumbrecht · Herzogenaurach, DE
• Christofer Hierold · Munich, DE
• Thomas Scheiter · Munich, DE

Key dates

• Filing date: May 30, 1997
• Grant date: Jun 29, 1999
• Expiry date: May 30, 2017

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N27/4148
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

In a method for manufacturing a combination of a pressure sensor and an electrochemical sensor, a basic structure for an ISFET is manufactured on a substrate made of silicon. After depositing a nitride layer as a pH-sensitive layer, the region of the ISFET is covered with a protective layer. In a region provided for a pressure sensor, a structured layer of polysilicon, provided as a membrane, is manufactured above a hollow space. Additional method steps for manufacturing electrical terminals of the sensors and, if required, additional integrated components, and for manufacturing printed conductor planes, are carried out in the context of a CMOS process. IMOX layers in the region of the gas sensor are wet-chemically removed down to the nitride layer. A platinum contact and an additional protective layer made of a PECVD oxide and a PECVD nitride are deposited. Additional layer structures for the gas sensor are manufactured. The pressure sensor is etched free either before the gas sensor is etched free, or after the deposition of the additional protective layer.