公开(公告)号：WO1989005963A1

公开(公告)日：1989-06-29

申请号：PCT/US1988004511

申请日：1988-12-16

Applicant: SIEMENS-BENDIX AUTOMOTIVE ELECTRONICS L.P.

Inventor： SIEMENS-BENDIX AUTOMOTIVE ELECTRONICS L.P. ,  LEE, Ki, W. ,  CHOI, Il-Hyun

IPC: G01D01/68

CPC classification number: G01L9/0048 ,  G01F1/6845

Abstract: A mass airflow sensor is fabricated on a semiconductor substrate (18) and includes a dielectric diaphragm (1), p-etch-stopped silicon rim (2), thin-film heating (3) and temperature sensing elements (4-7), and tapered chip edges (18). The dielectric diaphragm (1) is formed with thin silicon oxide and silicon nitride in a sandwich structure (32) and provides excellent thermal insulation for the sensing (4-7) and heating (3) elements of the sensor. The diaphragm (1) dimensions, including thickness, are accurately controlled through the use of the heavily-p-doped silicon rim (2) to help ensure uniform and reproducible sensor performance.

公开(公告)号：WO1989005968A1

公开(公告)日：1989-06-29

申请号：PCT/US1988004510

申请日：1988-12-16

Applicant: SIEMENS-BENDIX AUTOMOTIVE ELECTRONICS L.P.

Inventor： SIEMENS-BENDIX AUTOMOTIVE ELECTRONICS L.P. ,  LEE, Ki, W.

IPC: G01F01/68

CPC classification number: G01F1/6845 ,  Y10T29/49082 ,  Y10T29/4913

Abstract: A silicon-based sensor (10) includes a substrate (20), a sensor element (12), and a protective diaphragm (22a) mounting and covering the sensor element (12). The diaphragm (22a) is a silicon layer (22) which, in a preferred embodiment, includes an etch-stop dopant. The etch-stop layer (22) is sealed to the substrate (20) so that the layer (22) covers and mounts the sensor element (12) to the substrate (20). The sensor (10) is fabricated by forming a trough area (33) in a surface (32) of a silicon block (30) (e.g., a silicon chip or wafer), treating the trough area (33) with an etch-stop dopant (e.g., boron), depositing a sensor element (12) onto the doped trough area (33), sealing at least the periphery of the doped trough area (33) to a surface of a substrate (20) (e.g., glass) so as to encapsulate the sensor element (12), and then etching away undoped regions of the silicon block (30) so that the doped trough area (33) remains as a protective diaphragm (22a) sealed to the substrate (20) and covering the sensor element (12). It is also possible to form a bonding pad (16) on untreated (e.g., undoped) discontinuous regions (22c) of an otherwise etch-stop treated trough layer (34) so that when etched, the bonding pad (16) is exposed to permit interconnection with electronic circuitry, yet the etch-stop treated layer (22) remains so as to mount the bonding pad (16) to the substrate.

公开(公告)号：WO1989005967A1

公开(公告)日：1989-06-29

申请号：PCT/US1988004509

申请日：1988-12-16

Applicant: SIEMENS-BENDIX AUTOMOTIVE ELECTRONICS L.P.

Inventor： SIEMENS-BENDIX AUTOMOTIVE ELECTRONICS L.P. ,  LEE, Ki, W. ,  COOK, Charles, R., Jr.

IPC: G01F01/68

CPC classification number: G01F1/698 ,  B31B70/14 ,  B31B70/64 ,  B31B70/946 ,  B31B2155/001 ,  B31B2155/0014 ,  B65B43/123 ,  G01F1/6845

Abstract: A mass airflow sensor is disclosed which uses a small, thin dielectric diaphragm (1) providing good thermal isolation for thin-film heating (RH) and temperature sensing elements (RS1, RS2, RC1, and RC2), resulting in high flow sensitivity and low current operation of the heating element. The dielectric diaphragm is bounded by a p-etch-stopped silicon rim (2). The mass airflow sensor includes a primary sensor circuit which maintains a heated primary temperature sensing element (RS1) and an ambient air temperature sensing element (RC1) at a constant temperature difference. A slave sensor circuit, which includes a plurality temperature sensing elements (RS2 and RC2), monitors heat loss due to airflow at a particular location on the diaphragm (1) and generates an output signal (VOUT) indicative of airflow which is independent of ambient air temperature.