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Wafer Level Pressure Sensor and Method of Assembly

IP.com Disclosure Number: IPCOM000236757D
Publication Date: 2014-May-14
Document File: 5 page(s) / 187K

Publishing Venue

The IP.com Prior Art Database

Abstract

The proliferation of pressure sensor devices is increasing year on year. There are many uses for these sensing devices in the consumer, automotive and industrial market segments. In the automotive industry, pressure sensors are commonly found in the rims of car tyres, acting as pressure monitoring systems to detect low air pressure in the tyres. The existing pressure sensor portfolio in the industry is limited to leaded and plastic packages. The most common packages available in the industry are the pre-molded cavity quad flat non-lead (QFN), land grid array (LGA) and ball grid array (BGA) packages. In this paper we propose a wafer level pressure sensor package.

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TITLE

Wafer Level Pressure Sensor and Method of Assembly

ABSTRACT

The proliferation of pressure sensor devices is increasing year on year. There are many uses for these sensing devices in the consumer, automotive and industrial market segments. In the automotive industry, pressure sensors are commonly found in the rims of car tyres, acting as pressure monitoring systems to detect low air pressure in the tyres. The existing pressure sensor portfolio in the industry is limited to leaded and plastic packages. The most common packages available in the industry are the pre-molded cavity quad flat non-lead (QFN), land grid array (LGA) and ball grid array (BGA) packages. In this paper we propose a wafer level pressure sensor package.

CONTENT

There are many non-wafer level types of packages in the industry. The most commonly available are QFN and SOIC packages.  Packaging design has not changed much over the years with many leaded based packages still being used. 

In this paper, we present a wafer level pressure sensor device. The important components for forming this package are the silicon wafer with mask and etch processing to form a deep cavity. Metal traces are plated to form the electrical interconnection from the cavity to the bottom side of the package. Forming the cavity and metal traces layout are common in wafer level processing. In this package, this technology is further expanded to enable its use for pressure sensor packaging. Figure 1 shows the steps for assembling the proposed package.

Figure 1 Step in the fabrication of a wafer level pressure sensor package

Figure 2 shows an overview of the final assembled wafer level pressure sensor package.

Figure 2 Overview of  Wafer Level Pressure Sensor Packages

There are a few methods for encapsulating the cavity with the mold compound. The first method is to do a complete fill of the cavity, leaving no excess of the mold compound beyond the cavity. The second method, which is a more established method is about molding the entire wafer surface including the cavity with the mold compound. There is excess of mold co...