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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
Broadcom, the pulse logo, Connecting everything, Avago Technologies, Avago, and the A logo are among the trademarks of Broadcom and/or its affiliates in the United States, certain other countries, and/or the EU.
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The term “Broadcom” refers to Broadcom Inc. and/or its subsidiaries. For more information, please visit www.broadcom.com.
Broadcom reserves the right to make changes without further notice to any products or data herein to improve reliability, function, or design. Information furnished by Broadcom is believed to be accurate and reliable. However, Broadcom does not assume any liability arising out of the application or use of this information, nor the application or use of any product or circuit described herein, neither does it convey any license under its patent rights nor the rights of others.