Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Multi Functional Pressure Sensor Device

IP.com Disclosure Number: IPCOM000229678D
Publication Date: 2013-Aug-06
Document File: 4 page(s) / 141K

Publishing Venue

The IP.com Prior Art Database

Abstract

Fabrication of pressure resistivity transducer (PRT) wafers is a challenge. The active portion of the wafer has to go through multi step processes such as photo resist coating, etching, lapping and many more intricate steps to form the final device. Next, reactive ion etching is performed to create a cavity beneath the transducer layers before bonding to a silicon wafer. This silicon wafer has no specific use. It acts as a dummy layer to prevent vacuum leaking from the cavity, hence create a low vacuum environment for the transducer to function properly. This bonding process with a silicon wafer is a non-value added process on commercial point of view. Aside from sealing to establish the vacuum environment, it serves no other purposes.

This text was extracted from a Microsoft Word document.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 52% of the total text.

TITLE

Multi Functional Pressure Sensor Device

ABSTRACT

Fabrication of pressure resistivity transducer (PRT) wafers is a challenge. The active portion of the wafer has to go through multi step processes such as photo resist coating, etching, lapping and many more intricate steps to form the final device. Next, reactive ion etching is performed to create a cavity beneath the transducer layers before bonding to a silicon wafer. This silicon wafer has no specific use. It acts as a dummy layer to prevent vacuum leaking from the cavity, hence create a low vacuum environment for the transducer to function properly. This bonding process with a silicon wafer is a non-value added process on commercial point of view. Aside from sealing to establish the vacuum environment, it serves no other purposes.

CONTENT

Fabricating a pressure sensor device like a PRT wafer is a challenge. Packaging the device at the assembly site is another challenge. Non value added process step not only add to the complexity of the overall process but also increase on the cycle time and cost of the overall package.

In this paper we propose a means to address these shortcomings. First, by replacing the dummy silicon wafer with an active wafer such as an application specific (ASIC) wafer, non value added process and waste can be avoided during the wafer fabrication and bond processes. The ASIC die, after wafer dicing, allows direct interconnection to the substrate. It acts as a fully functional layer instead of just a dummy layer. Figure 1 shows the comparison between a dummy silicon bonded PRT versus an ASIC bonded wafer.

       Figure 1 Comparison between a dummy silicon bonded PRT wafer versus an ASIC bonded wafer.

Second, with this stacked up structure, we are able to reduce the overall assembled package size and thickness. The package size can be made smaller since we do not need to have the ASIC and PRT dies side by side. Figure 2 illustrates the comparison. With the 2 dies placed side by side, the package dimension is X. With the PRT bonded to the ASIC back to back and placed on the substrate, the dimension is much reduced to a value lesser than X.

Figure 2 Comparing ASIC / PRT...