CMA3000 Assembly Instructions

1

Objective

This document describes guidelines for Printed Wiring Board (PWB) design and assembly of the

CMA3000 3-axis Accelerometer. It also aims to help customers achieve the optimum soldering

process.

2

VTI's 3D Stacked Wafer Level Chip-on-MEMS Package (CoM)

CMA3000 features a novel packaging concept, which is called Chip-on-MEMS (CoM). Its approach

has been to maintain the benefits of manufacturing the MEMS devices and ASICs on separate

wafers. For this Chip-on-MEMS concept, ASIC chips are flip-chipped onto the MEMS wafer in

known good locations. Redistribution and isolation layers are applied to the MEMS wafer, solder

spheres are provided for external connection before the ASICs are added and the MEMS and

ASIC chips are then isolated using a passivation layer. The concept is illustrated in Figure 1.

Figure 1.

The concept of the CMA3000 component.

CoM-technology offers a variety of benefits including reduced lead inductance, an extremely small

sized chip scale package, less than 1mm thin profile, low weight, excellent solderability and

reworkability due to solder spheres. Because the CoM-technology represents the latest in the

surface mount packaging technology, it is important that the design of the printed wiring board, as

well as the assembly process, follow the suggested guidelines outlined in this document.

It should be emphasized that these guidelines are general in nature and should only be considered

as a starting point. The user must employ their actual experiences and development efforts to

optimize designs and processes for their manufacturing practices and the needs of varying end-

use applications.

Subject to changes

TN68

3/18

Rev.09

PRELIMINARY

VTI Technologies Oy

www.vti.fi