SCA3000

SCA3000 VTI | Alldatasheet

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SCA3000 Assembly Instructions SCA3000 Series 3-axis accelerometer

SCA3000 Assembly Instructions TABLE OF CONTENTS VTI Technologies Oy Subject to changes 2/15 www.vti.fi TN54 Rev.C

1 Objective

SCA3000 Component. It aims to help customers achieve the optimum soldering process. and experience to be able to fulfill the needs of varying end-use applications.

2 VTI's Molded Interconnection Device Package (MID)

molded interconnection device (MID), which is a modified Dual Flat-pack No-lead package (DFN). surface mount plastic package with leads located at the bottom of the package, see picture 1. Figure 1. 3D pictures of the SCA3000 component. The SCA3000 component leads are located at process flow of LDS - MID package is presented in figure 2.

The outline and dimensions for the SCA3000 MID package are presented in figure 4. Figure 4. Outline and dimensions of the SCA3000 component.

4 Tape and reel specifications

in figure 5, table 1 and table 2 below (dimensions are in millimeters [mm]). Table 1. SCA3000 packing tape pocket dimensions [mm]. Figure 5. SCA3000 packing tape and component orientation on tape. Table 2. Dimensions for SCA3000 packing tape [mm].

Figure 6. Reel dimensions. Table 3. SCA3000 Packing reel dimensions [mm]. Both tape and reel are ESD materials and they are suitable for baking for 24 hours at +125°C.

5 Printed Wiring Board (PWB) Level Guidelines

5.1 Land Pad Design

2) Solder Mask Defined Pads (SMD). PWB land pattern for the SCA3000 component is presented in figure 7. Figure 7. Recommended PWB pad layout for SCA3000 component. VTI's SCA3000 packages can be soldered on commonly used substrates, e.g. FR-4, ceramic etc. pitch SMD soldering are NiAu, OSP, Electroless-Ag and Electroless-Sn.

5.2 Solder Paste

RoHS compatibility lead-free solder should be used for the soldering of VTI's SCA3000 component. free process is not required. With the eutectic SnPb solder, the melting point is 183°C. dimensions. Type 3 paste is recommended (grain size 25-45mm).

SCA3000 Assembly Instructions

5.3 Stencil

The solder p aste i s applied o nto the PWB by u sing ste ncil pri nting. The ste ncil thi ckness a nd aperture determines the p recise volume of solde r paste deposited onto the lan d pattern. Stencil alignment accuracy a nd consistent solder volume transfer are im portant parameters for a chieving uniform reflo w soldering results. To o much solder paste can ca use b ridging and to o little solder paste can cause insufficient wetting. G enerally the stencil thickness needs to be match ed to the needs of all components on the PWB. For the SCA3000 MID-package the recommended stencil thickness is 5mils (127µm). Stencil apertures in general should be 1:1 to P WB pad sizes, or stencil apertures could even be reduced by 1 mil (25.4µm ) from all sid es in rega rd to the PWB land pa d si ze. This re duction of aperture size can reduce bridging between solder joints.

5.4 Paste Printing

The pa ste p rinting sp eed should be adjusted according to the solder paste specifi cations. It is recommended that care be taken during paste printing in order to ensure correct paste amount, shape, position, and other printing characteristics. Neglecting any of these can cause open solder joints, bridging, solder balling, or other unwanted soldering results.

5.5 Component Picking

The SCA3000 component can be picked from the carrier tape using either vacuum assist or mechanical type pick heads. Typically a vacuum nozzle is used. Pick up nozzles are available in various sizes and shapes to suit a variety of different component geometries. It is recommended that different pick up nozzles are tested to find the best one. The polarity of the part must be assured in taping process. The polarity of the part on tape is presented in figure 5 on page 4.

5.6 Component Placement

SCA3000 MID pa ckages must b e pl aced onto P WB a ccurately accordi ng to their g eometry. Positioning the packa ges manually is n ot recommended. Placement should be done with modern automatic component pick & place machinery using vision systems. Recognition of the pa ckages automatically by a v ision system enabl es correct centering of packages.

5.7 Reflow Soldering

A forced convection reflow oven is recommended to be used for soldering SCA3000 components. IR-based reflow ovens are not generally suitable for lead-free soldering. Figure 8 presents a general forced convection reflow solder profile and it also shows the typical phases of a reflow process. The reflow profile used for soldering the SCA3000 package should always follow the solder paste manufacturer's sp ecifications an d re commended p rofile. The typical ramp -up rate is 3 °C/second max. The reflow max. pea k temperature (measured from the component body) should n ot exceed 260°C. The ramp down rate should be 6°C/second max. VTI Technologies Oy Subject to changes 9/15 www.vti.fi TN54 Rev.C

Figure 8. Typical convection reflow soldering phases and profile. The process window for le ad-free soldering is n arrower than for tradition al eutectic SnPb solders. contains components with vastly different thermal masses.

5.8 Moisture sensitivity level (MSL) classification

260°C/40sec, measured from the package body.

5.9 Inspection

soldered component on PWB looks from different directions.

SCA3000 Assembly Instructions

6 Re work Guidelines

There are several rework systems on the market. Some will heat solder joints directly from the sides of component package, while others will direct heat on the top of component. Occasionally, very rough rework methods are used such as hand placement and heating with a soldering iron. However, these rough methods are not suitable for VTI's MID components. The heat flow of hot-air convection should be directed at the edge and under the component body directly to the solder joints and component pad areas. The package has a limited thermal conductivity and thus, a horizontal flow method, a conduction method, or a conduction heating from the top of the package to the solder joints should not be used. Prior to the rework process, PWBs and components should be free from moisture. If necessary, baking and drying processes should be performed. The reflow profile for the component removal should be similar to the initial reflow. A carefully adjusted reflow profile is essential for the successful rework operation. A proper reflow profile should be measured with thermo-couples. During the reflow profiling, at least the solder joints, the top of the component, and the bottom of the PWB should be monitored. If there are other components near the component to be reworked, the temperatures of those should also be monitored. The bottom side heating of the PWB is recommended in order to reduce the PWB warpage during the rework operation. Once the solder joints have been fully melted, the component can be carefully removed from the PWB. The common rework methods for the component removal can be used, i.e. a vacuum nozzle etc. It is absolutely necessary to ensure the complete melting of the solder joints before the component lifting. If the solder joints are not fully melted before the lifting operation, pad damage may occur on the PWB and the component. After the component is removed, the pad areas of the PWB should be cleaned using common rework methods. These include the applying of a rework flux, an excess solder and flux removal using a vacuum solder removal tool or a solder wick and a soldering iron with a wide chisel tip, and the cleaning of solder pads with alcohol and brush. The PWB cleaning process should be performed gently as too high force or a scrubbing motion can cause pad lifting and trace damage. If the component reuse is desired, it should be carefully inspected for a potential damage, solder residues should be removed, and the pads should be cleaned. Prior to the placement of a replacement component on to the reworked PWB, a solder paste should be applied on the cleaned PWB pads. Suitable methods for applying the solder paste are the usage of a micro-stencil or the dispensing of the solder paste. If the micro-stencil is used, it should be cleaned after each paste application to prevent clogging. For the solder paste and the stencil, the same guidelines as for the initial reflow process should be used. The accurate alignment of the component is an important process step thought the surface tension of the solder during the reflow step will help with the self-alignment. The use of a split-vision alignment system is recommended to ensure the precise alignment of the component to the PWB. The "Z" placement force should be carefully controlled in order to prevent the solder bridging. The same reflow profile, as for the component removal, can be used for the re-attachment of the replacement component as long as all solder joints will fully melt and properly wet the contact areas. Otherwise, a new and proper reflow profile must be developed and measured from the solder joints. The reworked PWBs should be allowed to cool to the room temperature. The PWBs and the components should be inspected after the rework process for possible defects. The use of X-ray inspection techniques can be used to verify the success of the rework process. It should be noted, that the performance and the reliability of the reworked component may have decreased due to the rework operation. VTI Technologies Oy Subject to changes 12/15 www.vti.fi TN54 Rev.C

7 Hand Soldering Guidelines

SCA3000 component, VTI can provide pre-assembled component on a PWB. due to the lower melting point compared to lead-free solder pastes. or soldering iron to melt the paste and achieve the soldered joint. presented in more detail below. Figure 11. Recommended PWB land pad lengthening for and soldering. solder paste and component leads. See figure 12 for details. Figure 12. Narrowed PWB signal traces and use of soldering iron.

SCA3000 Assembly Instructions 1. Apply the solder paste onto the PWB land pads. The paste can be applied by two different methods. - Manual solder paste printing through a stencil with normal openings designed for the SCA3000 component. - Needle dispensing of solder paste manually onto the PWB pads. VTI recommends use of a microscope in manual solder paste dispensing. Dispensing needle tip size can be 0.12"-0.16". 2x amount of solder paste compared to smaller PWB soldering pads Figure 13: Solder paste (grey) on PWB land pads. 2. Place the component gently on top of the solder paste. To avoid solder bridging, push only very gently on top of the component. 3. i) Melt the so lder paste by putting the part throu gh reflow oven or ii) by using soldering iron. When using soldering iron, do not tou ch the package plastic body, soldering iron should touch only the extension in the PWB's land pad through that the heat should be conducted to melt the solder paste and th en fo rm the solder joint to the component l ead. See fig ure 11 above for details.

8 Environmental Aspects

VTI Technologies respects environmental values and thus its MID packa ged pressure sensors are lead-free an d RoHS com patible. VTI Tech nologies’ sensors sh ould be sold ered with le ad-free solders in order to guarantee full RoHS compatibility. VTI Technologies Oy Subject to changes 14/15 www.vti.fi TN54 Rev.C

SCA3000 Assembly Instructions

9 References

JEDEC / Electronic Industries Alliance, Inc. Moisture/ReflowSensitivity Classification for Non- Hermetic Solid State Surface Mount Devices (J-STD-020C).

10 Document Revision History

Version Date Change Description Rev. A 30.06.2006 First release Rev. B 27.09.2006 Rework guidelines added. Corrections to reel dimensions Rev. C 13.02.2007 Corrections to reflow soldering VTI Technologies reserves all rights to modify this document without prior notice. VTI Technologies Oy Subject to changes 15/15 www.vti.fi TN54 Rev.C