Application Note 5520

AMxP-XXXX Production Assembly Process (Land Pattern A)

Description

This application note describes and illustrates the attachment and detachment of the Broadcom® 5 mm × 5 mm packaged products in a PCB (soft board) environment. The AMxP package has a solid copper-filled cavity to allow optimum thermal transfer from the packaged device to the PCB and associated heat sink interface.

The AMxP package takes into full account the parasitics involved with routing a high-frequency signal up and through a ground plane transition; therefore, these guidelines also illustrate measures that optimize the RF signal interface. Figure 1 illustrates an AMxP package assembly. Figure 2 is a cross-sectional view.

Figure 1: AMxP-XXXX DC-45 GHz Package

Figure 2: Cross-sectional View of an AMxP-XXXX Package

AMMP-XXXX Package Plating

Electrolytic Ni-Au (Ni 3-8 µm, Au 0.3-0.55 µm) is used for backside plating to ensure industry standard lead or lead-free solder adhesion.

Package Features Surface mount package (5.1 mm × 5.1 mm × 2 mm)

Tape and reel capability for chip shooter pick-and-place applications

Broadcom AV02-2954ENAugust 31, 2018

AMxP-XXXX Application Note 5520 Production Assembly Process (Land Pattern A)

Package Dimensions and Tolerances

NOTE:

1. ° Indicates Pin 1.

2. Dimensions are in millimeters.

3. All grounds must be soldered to PCB RF ground.

4. Dimension tolerance = 0.05 mm unless otherwise indicated.

Stencil Type

A stainless steel stencil with trapezoidal walls is recommended. If possible, electropolishing for smooth walls will reduce surface friction and promote good paste release. The trapezoidal section aperture (TSA) design also promotes precision solder deposits to assist in component placement and alignment. The resulting, reflowed solder joints on the perimeter I/O lands should measure approximately 50 mm to 75 mm (2 to 3 mils) standoff height.

Figure 3 shows a stencil pattern that will give an optimum amount of solder paste that maximizes contact coverage and minimizes paste thickness, which would degrade RF signal performance.

Figure 3: Solder Stencil Dimensions

Solder Paste

The recommended solder paste is SolderPlus 62NCLR-A/Sn62 Pb36 Ag2 (Engineered Fluid Dispensing). Details can be obtained from http://www.efd-inc.com.

Conductive epoxy is not recommended. Hand soldering is not recommended.

If the vias on the PCB are not silver filled, taping the backside of the PCB with thermal tape is recommended prior to dispensing the solder paste. This will help contain the solder in the vias. This is critical for good thermal transfer from the package to the PCB and heat sink. Remove the thermal tape after the cool down period of the solder process.

321

567

48

A

A

AMxP

XXXX

YYWWXX

FRONT VIEW

B

SIDE VIEW

Dimensions are in mm

Symbol Min. Max.

A 5.0 5.2

B 1.77 2.20

BACK VIEW

1.040.70

2.491.47

0.560.38

0.77

0.25

0.52 0.1 0.39

0.3

0.55

0.15

0.36

2.79

Broadcom AV02-2954EN2

AMxP-XXXX Application Note 5520 Production Assembly Process (Land Pattern A)

If lead-free solder is required, a “no clean” Type 3 paste per ANSI/J-STD-005 is recommended. Nitrogen purge is also recommended during reflow.

For automated assembly, solder paste should be screen printed before reflow. Figure 4 illustrates the solder deposit pattern superimposed on the PCB.

Figure 4: Solder Paste Pattern on PCB

Manual Solder Dispensing Guidelines

For manual dispensing of solder paste on the PCB, it is critical to distribute the solder paste evenly across the pattern shown in Figure 4. The solder paste should be distributed evenly with a thickness of approximately 0.075 mm (0.003 in.). An uneven solder distribution may cause voids underneath the package or non-contact on parts of the package bottom. Too much solder paste can bridge the contact pads.

Figure 5A, Figure 5B, and Figure 5C illustrate good and poor solder paste distribution.

Figure 5: Solder Paste Distribution Examples

PCB Land Pattern and Material

The PCB material and mounting pattern, as defined in the data sheet, optimizes RF performance, and Broadcom strongly recommends it be followed. An electronic drawing of the land pattern is available upon request from Broadcom sales or application engineering.

Figure 6 shows the land pattern. Material is Rogers RO4350 with a thickness of 0.25 mm (0.010 in.).

For products with approximately 2W or greater power dissipation, silver filled vias or a solid copper base are highly recommended.

AMxP package mounted with good solder distribution under the contact pad area

5A

5B

5C

AMxP package mounted with too much solderunder the contact pad area (center)

void

AMxP package mounted with too little solderunder the contact pad area (void exists that causes poor heat transfer)

void

Broadcom AV02-2954EN3

AMxP-XXXX Application Note 5520 Production Assembly Process (Land Pattern A)

Figure 6: AMxP-XXXX Land Pattern (mm)

Solder Reflow

Reliable assembly of surface mount components is a complex process that involves many materials, processes, and equipment factors, including: method of heating, circuit board material, conductor thickness, pattern, type of solder paste and solder alloy, thermal conductivity, and thermal loading and mass of components. Reflow temperature settings need to be determined by the end user based on these considerations. Also, moisture sensitivity MSL level 2A has been qualified for this device. The MSL level 2A conditions must not be exceeded.

After ramping up from room temperature, the circuit board with components held in place with solder paste passes through one or more preheat zones. The preheat zones increase the temperature of the board and components to prevent thermal shock and to evaporate solvents from the solder paste. The reflow zone briefly elevates the temperature to produce a reflow of the solder.

Profile for Solder Reflow

The reflow profile investigated and recommended by Broadcom for this product is based on JEDEC/IPC standard J-STD-020 revision C. This device has been qualified to withstand a maximum of three cycles of solder reflow according to the conditions of J-SDT-020C, and this device has been qualified for moisture sensitivity level 2a.

Table 1 lists the parameters and peak temperatures as indicated by JEDEC/IPC. Figure 7 shows the standard lead-free JEDEC/IPC profile. The most recommended and most common reflow method uses a belt furnace with convection/ IR heat transfer.

Table 1 shows the actual temperature range that should occur on the surface of a test board at or near a central solder joint. During this type of reflow soldering, the circuit board and solder joints tend to heat first. The components on the board are then heated by conduction. The circuit board, because it has a large surface area, absorbs thermal energy more efficiently, and then distributes this heat to the components.

A prolonged preheat stage is not recommended as oxidation may occur on the solder paste surface. A reflow temperature over 217°C is critical and will determine the appearance of the solder joint after reflow. Longer reflow time may result in a dull and gritty solder joint appearance and charring of flux residues. Time below 30 seconds may result in insufficient wetting and poor intermetallic formation. Too fast of a cooling rate could result in insufficient wetting and poor intermetallic formation.

As a general guideline, the AMxP package should be exposed to only the minimum lead free process temperature and times necessary to achieve a uniform reflow of solder on the board. The rates of change of temperature for the ramp-up and cool-down zones are specified by the J-STD-020C standard to be low enough to not cause deformation of the board or damage to components due to thermal shock. This profile allows a reflow temperature which is low enough to avoid damaging the internal circuitry during solder reflow operations provided the time of exposure at peak reflow temperature is not too excessive.

Also refer to the specific AMxP-XXXX product data sheet for further information.

3.2

0.46

0.28

0.25

2.9

0.41

0.24

0.41

0.31

0.240.462.38

1.5 0.51

For >=2W dissipation,

Vias under package

should be silver filled.

Broadcom AV02-2954EN4

AMxP-XXXX Application Note 5520 Production Assembly Process (Land Pattern A)

NOTE: All temperatures refer to topside of the package, measured on the package body surface.

Reference

1. JEDEC/Electronic Industries Alliance, Inc, "Moisture/Refl ow Sensitivity Classification for Non-hermetic Solid State Surface Mount Devices (IPC/JEDEC J-STD-020C)," July 2004.

Table 1: Lead-Free Refl ow Profi le Recommendation (IPC/JEDEC J-STD-020C)

Reflow Parameter Lead-Free Assembly

Average ramp-up rate (Liquidus Temperature TS(max) to Peak) 3°C/s max.

Preheat Temperature Min. (TS(min)) 150°C

Temperature Max. (TS(max)) 200°C

Time (min. to max.) (tS) 60s to 180s

TS(max) to TL Ramp-up Rate 3°C/s max.

Time maintained above: Temperature (TL) 217°C

Time (TL) 60s to 150s

Peak temperature (TP) 260°C +0°C/–5°C

Time within 5°C of actual Peak Temperature (TP) 20s to 40s

Ramp-down Rate 6°C/s max.

Time 25°C to Peak Temperature 8 minutes max.

Hydrogen Poisoning of GaAs Semiconductors

Metals sensitive to hydrogen poisoning are palladium (Pd), platinum (Pt) and titanium (Ti). Broadcom’s AMxP GaAs devices contain some of these metals in the gate structure.

Electroplated metal packages can release hydrogen that is absorbed during the plating process; thus, sealing an AMxP packaged device in a hermetic environment, where hydrogen may be present, will subject it to hydrogen which may penetrate into the gate structure through the package. Precautionary measures are recommended for use of AMxP-XXXX parts in hermetic enclosures where hydrogen may be present.

Hydrogen “Getter”

A hydrogen getter is a material typically made with hydrogen-absorbing platinum or palladium metals or oxides like PdO. Current suppliers of hydrogen "getters" are shown in the following table.

Hi-Rel www.hirelgroup.com

SAES Group www.saesgetters.com

KRA FAB www.krafab.com

Vacuum Energy www.vacuumenergyinc.com

Broadcom AV02-2954EN5

AMxP-XXXX Application Note 5520 Production Assembly Process (Land Pattern A)

Figure 7: Standard J-STD-020C Lead-Free Solder Reflow Profile

De-Soldering the AMxP Package

De-soldering can be done by hot-air, hot-tip contact or on a hot plate. An example of hot-plate de-soldering is shown in Figure 8. An aluminum block, sized to fit under the 5 mm × 5 mm package, is used to transfer the heat from the hot plate. The aluminum block centralizes the heat under the package; thus, avoiding reflow of surrounding components. When the solder has reflowed, the package should be removed by gripping it with tweezers from the bottom section.

Figure 9 shows a typical hot plate set to approximately 200°C, an AMxP PCB assembly, and an aluminum block that fits under the package area.

Figure 8: Hot Plate De-soldering

TIME

TEM

PER

ATU

RE

tp

t 25° C TO PEAK

tsPREHEAT

TL

TP

Tsmax

Tsmin

tL

CRITICAL ZONE TL TO TP

RAMP UP

RAMP DOWN

25

PACKAGEPackage Top

Aluminum Block

Package Bottom

PCB

Hot Plate

Broadcom AV02-2954EN6

AMxP-XXXX Application Note 5520 Production Assembly Process (Land Pattern A)

Figure 9: Typical Hot Plate and Components

Figure 10 and Figure 11 show the manual removal of an AMP package using tweezers.

Figure 10: AMxP Package on an Aluminum Block

Figure 11: Removal of an AMxP Package with Tweezers

Aluminum block

Gold plated

copper block

AMxP

PCB

assembly

AMxP PCB assembly on

top of aluminum block

Broadcom AV02-2954EN7

AMxP-XXXX Application Note 5520 Production Assembly Process (Land Pattern A)

Hot Air Desoldering

Hot Air Equipment

Figure 12: HAKKO FM202 Digital Soldering SMD Rework Station and Nozzle: A1130

Figure 13: AMxP-XXXX Package Soldered on a PCB

Figure 14: PCB Secured for Access underneath the PCB

Figure 15 shows an illustration of blowing hot air underneath a demonstration board by using the hot air nozzle, and at the same time using tweezers to grip the bottom side walls of the AMxP package.

Figure 15: Blowing Hot Air underneath the PCB

Broadcom AV02-2954EN8

AMxP-XXXX Application Note 5520 Production Assembly Process (Land Pattern A)

Hot Tip Contact Desoldering

Hot Tip Equipment

Figure 16: HAKKO 850D Rework Station and Tip P/N T7-D4

When unsoldering a part using a hot iron tip, the size of the tip will actually depend on the thickness and material composition of the PCB. A #T7-D4 tip is sufficient for Broadcom’s mmWave demonstration board PCB stackups.

Figure 17 and Figure 18 illustrate the tip contact to a copper heat sink that is soldered to a two-layer PCB with either silver filled vias or a solid copper base under the ground area of the AMxP device.

Figure 17: Hot Tip Desoldering 1

PACKAGE TOPPACKAGE

PACKAGE BOTTOM

PCB

COPPER HEATSINK

Direct contact is

made under the

package surface

area.

Broadcom AV02-2954EN9

AMxP-XXXX Application Note 5520 Production Assembly Process (Land Pattern A)

Figure 18: Hot Tip Desoldering 2

Special Handling Notes for Automatic and Manual SMT Rework Package should be cooled down before any solution

cleaning after IR reflow.

Follow ESD precautions while handling packages.

Solder coverage should be evenly distributed across the bottom contact area to obtain good, reliable DC and RF contact.

Alignment and good wetting of the RF input and output pads to the PCB is critical to ensure optimum signal transmission.

Handle the package along its edges with tweezers. Automatic placing with a vacuum force from the top of the lid is recommended.

DC probe or other sharp instrument contact is prohibited in the bottom center area outlined in Figure 19. DC probe contact or other sharp instrument contact is allowed in the area marked “A”.

For volume production, the AMxP package can be treated as a standard surface mount component (reference IPC/JEDEC J-STD-020C standard or equivalent) with a standard assembly process. (for example, stencil solder printing, standard pick and place and solder reflow oven).

Marking Code:

PACKAGE TOPPACKAGE

PACKAGE BOTTOM

PCB

COPPER HEATSINK

Keep direct contact

under the package

surface area.

Lift package, with tweezers from

the bottom side walls when solder

has reflows.

AMxP = x refer to wafer technologies

XXXX = device code

YYWWXX = date code

YY = year

WW = work week

XX = no of lot in the day (Lot 01-10)

Broadcom AV02-2954EN10

AMxP-XXXX Application Note 5520 Production Assembly Process (Land Pattern A)

Figure 19: Prohibited Probing Area RF Port Transitions

It is important to note that RF port hardware, such as SMA 2.92 mm or 2.4-mm connectors, will directly contribute loss and limit AMxP performance within the hardware’s bandwidth.

Table 2 is a list of recommended edge launch connectors used in Broadcom’s mmWave evaluation and demonstration board modules. Other connectors similar to the performance of these connectors will also be suitable.

Websites for Connector Manufacturers

http://www.southwestmicrowave.com

http://www.EmersonNetworkPower.com

Bypass Capacitors

Bypass capacitors, as recommended on Broadcom AMxP data sheets for the DC output pins, should be as close to the package as possible. Table 3 lists two typical capacitor values and their part numbers. Other capacitors similar in specification may be substituted.

AMxPXXXXYYWWXX

A

AA

5.08 mm

5.08 mm

No direct

probing allowed

on this area.

RF IN

Table 2: Recommended Launch Connectors

Connector Type Bandwidth Manufacturer Female Part Number Male Part Number

SMA (screw on) DC-27 GHz Southwest Microwave 292-06A-5 293-03A-5

SMA (solderable) DC-26.5 GHz Johnson 142-0761-841-A

SMA (solderable) DC-26.5 GHz Johnson 142-0761-851-A

SMA (solderable) DC-26.5 GHz Johnson 142-0761-891-A

2.92 mm (screw on) DC-40 GHz Southwest Microwave 1092-04A-5 1092-03A-5

2.4 mm (screw on) DC-50 GHz Southwest Microwave 1492-03A-5 1493-03A-5

Table 3: Capacity Values and Part Numbers

Capacitor Type Value Manufacturer Part Number

SMT 0402 0.1 mF AVX AVX0402YG104ZAT2A

SMT-0805 >1 mF (4.7 mF) Phycomp 08052F47SZ6BBOD

Broadcom AV02-2954EN11

AMxP-XXXX Application Note 5520 Production Assembly Process (Land Pattern A)

Carrier Tape and Pocket Dimensions

Device Orientation (Top View)

Ordering Information

Part Number Devices Per Container Container

AMxP-XXXX-BLKG 10 Antistatic bag

AMxP-XXXX-TR1G 100 7-in. Reel

AMxP-XXXX-TR2G 500 7-in. Reel

KoKo

Bo

Bo

Ao

SECTION B-B

SECTION A-A

Ao

0.30 0.05

B

B

A A

1.75 0.10

5.50 0.05

12.00 0.10

R 0.50 TYP.

1.55 0.05

8.00 0.101.50 (MIN.)

4.00 0.10

SEE NOTE #2

2.00 0.05

Ao :

Bo :

Ko :

PITCH :

WIDTH :

5.30

5.30

2.20

8.00

12.00

Ao Bo Ko

MIN. 5.20 5.20 2.10

NOM. 5.30 5.30 2.20

MAX. 5.40 5.40 2.30Notes:1. Ao and Bo measured at 0.3 mm above base of pocket.2. 10 pitches cumulative tolerance ±0.2 mm.

12 mm

4 mm

AMxPXXXXYYWWXX

AMxPXXXXYYWWXX

AMxPXXXXYYWWXX

Broadcom AV02-2954EN12

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