M570 [TE]
Bonding, Handling, and Mounting Procedures for Millimeterwave PHEMT MMIC’s; 对于毫米波MMIC PHEMT的粘接，搬运和安装过程
| 型号： | M570 |
| 厂家： | 
TE CONNECTIVITY |
| 描述： | Bonding, Handling, and Mounting Procedures for Millimeterwave PHEMT MMIC’s |
| 文件： | 总4页 (文件大小：167K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Application Note
M570
Bonding, Handling, and Mounting Procedures for
Millimeterwave PHEMT MMIC’s
M/A-COM Products
Rev. V4
Discussion
die attach and top contact operations are performed by
M/A-COM Tech and all devices are RF tested after assem-
bly into the packages. When the circuit fabricator performs
the die attach and wire bonding operation on a complex
substrate, he/she runs the risk of losing or damaging a chip
during the bonding operation which can result in the loss of
the whole circuit or in an expensive rework cycle.
Millimeterwave MMIC's are becoming more common in
commercial applications. Their small size and potentially
lower cost has made them valuable in the growing mar-
ket of millimeterwave systems. Their size and delicate
nature also makes them fragile. The following informa-
tion is provided to help die users handle, mount, and
bond MMIC chips.
The most common issues that arise when bonding MMIC's
to the circuit are: the introduction of excessive series resis-
tance, especially under forward bias conditions due to the
improper bonding of the chip to the ground plane; poor reli-
ability due to the entrapment of contaminates under the
bond; and mechanical failure of the bond under thermal
shock or temperature cycling. All three conditions are the
result of improper wetting of the die to the ground plane and
are usually caused by inadequate cleanliness or inadequate
bonding conditions.
It should be noted that MMIC's usually require special-
ized equipment for die attachment and bonding. These
operations require a clean environment and special han-
dling equipment such as vacuum pickups, hot gas bond-
ers and/or thermal compression and/or thermo-sonic
bonding equipment.
M/A-COM Tech offers a family of GaAs MMIC amplifiers
above 15 GHz. This note addresses:
Table 1 provides helpful information in the selection of die
down techniques.
GaAs MMIC Devices
Low Noise Amplifiers
Power Amplifiers
Gain Blocks
Chip Die Down Bonding Techniques
Driver Amplifiers
Eutectic Bonding of Chips - Power Amps
The eutectic bonder is one of the most convenient ways of
bonding chips onto a metal ground plane or circuit. Both
silicon and GaAs chips may be bonded using similar tech-
niques.
Handling and Assembling of Chips and
Circuits
The challenges of handling and assembling chips into
packages can be best separated into two areas: putting
the chip into the circuit (die down) and making top con-
tact to the chip (top bonding).
GaAs power die are back metallized with Ti/Au metalliza-
tion. The use of gold tin solder perform (80% Au, 20% Sn)
with an eutectic melting point of 295 ± 5˚C is recommended.
A clean, flat, gold plated surface is required to insure good
wetting. The preform should be large enough to insure that
the die fits within the areas shown, should be ~1 mil thick,
and should be 10% smaller than the die itself. During the
attaching process, the die collet should be “scrubbed,”
rubbed into the eutectic, to ensure a good die attach. The
carrier of package temperature and collet temperature
should be 295 ± 5˚C. There should be a 90/10 nitrogen/
hydrogen gas applied to the bonding surface. When the
forming gas is applied ensure that the bonding surface tem-
perature does not fall below the recommended temperature.
This should be done only for the die. All other components -
50W lines, caps, resistors - should be done with electrically
conductive epoxy. DO NOT expose the die to a tempera-
ture greater than 320˚C for more than 20 seconds.
Permanent damage to the MMIC may occur if the pre-
cautions are not followed. The MMIC's should be han-
dled in a clean room type of environment. All devices
are static sensitive, so handling equipment and person-
nel should comply with DOD-STD-1686 Class I. Avoid
instrument and power supply transients while bias is
connected to the MMIC. Use shielded signal and bias
cables to minimize inductive pick-up. In general, DO
NOT touch the surface of the die. It is recommended
that the MMIC die be handled with vacuum pick-up tools
with rubber or soft material or handled along the long
side with tweezers.
Chip Bonding Methods
A recommendation for improved bonding is to plasma
clean the carrier before any eutectic is used. The MMIC
should be plasma cleaned before wire bonding.
A risk in using MMIC's is the possible damage incurred
when assembling chips into circuits. In general, the
value of the MMIC circuits exceeds the cost of the MMIC
chip itself. When packaged MMIC's are used, the critical
1
ADVANCED: Data Sheets contain information regarding a product M/A-COM Technology Solutions
is considering for development. Performance is based on target specifications, simulated results,
and/or prototype measurements. Commitment to develop is not guaranteed.
PRELIMINARY: Data Sheets contain information regarding a product M/A-COM Technology
Solutions has under development. Performance is based on engineering tests. Specifications are
typical. Mechanical outline has been fixed. Engineering samples and/or test data may be available.
Commitment to produce in volume is not guaranteed.
• North America Tel: 800.366.2266 • Europe Tel: +353.21.244.6400
• India Tel: +91.80.43537383
• China Tel: +86.21.2407.1588
Visit www.macomtech.com for additional data sheets and product information.
M/A-COM Technology Solutions Inc. and its affiliates reserve the right to make
changes to the product(s) or information contained herein without notice.
Application Note
M570
Bonding, Handling, and Mounting Procedures for
Millimeterwave PHEMT MMIC’s
M/A-COM Products
Rev. V4
Resultant
Thermal
Resistance
High
Power
Special
Equipment
Required
Die Down
Method
Temperature Temperature Handling Ease of
Capabilities Capability Operation
Potential
Problems
Required
Conductive
Epoxy
Good with
proper
technique
Room temp to
Good
Low to
medium
power
Easiest to
apply
Little to none
High series or thermal
resistance
150˚C
Soft solder i.e., Good to very
200 - 280˚C
180 - 200˚C
Good
Good to very
good for low
or high
Simple
application
Heated stage Flux is usually required
Pb-Sn-Ag
(90,5,5)
good
hot gas
bonder or gas
curtain and
furnace
with lead solders.
Cleaning of flux must
be done carefully
Pb-Sn (60,40)
power
Eutectic Solder
Au-Sn (80,20)
Sn-Sb (97,3)
Very good
Approx. 300˚C
Approx. 230˚C
Good
Very good
Simple
application
Heated stage Needs clean reducing
or hot gas
bonder
atmosphere
Table 1. Selection Guide for Die Down Bonding Techniques
Figure 1. Die Bonding Criteria
The attachment surface should be clean and flat. Electri-
cally conductive epoxy is required and must be within the
warranty shelf and/or pot life. It is advisable to use half
the listed pot life. Silver conductive epoxies should not
be used where they will come into contact with lead tin
solders or high tin solder. There can be an anodic reac-
tion which may cause failure of the bond. Epotek H2OE
or Ablestick 84-1LMI is recommended.
Die Bonding with Conductive
Epoxies - LNAs
Although satisfactory die down bonds may be obtained
using these epoxies, the power amplifiers may not per-
form to specification. The low noise amplifiers work well
when epoxies are used. The following precautions
should be observed to obtain consistently strong bonds.
A minimum amount of epoxy should be applied, then the
die should be placed into position. Figure 1 shows good
and unacceptable bonds.
The low noise die are back metallized with Pd/Ni/Au
(100/ 1,000 / 30,000Å) metallization. Thermally and
electrically conductive epoxy is recommended for die-
mounting the low noise die, although Au/Sn eutectic
preforms can be used.
2
ADVANCED: Data Sheets contain information regarding a product M/A-COM Technology Solutions
is considering for development. Performance is based on target specifications, simulated results,
and/or prototype measurements. Commitment to develop is not guaranteed.
PRELIMINARY: Data Sheets contain information regarding a product M/A-COM Technology
Solutions has under development. Performance is based on engineering tests. Specifications are
typical. Mechanical outline has been fixed. Engineering samples and/or test data may be available.
Commitment to produce in volume is not guaranteed.
• North America Tel: 800.366.2266 • Europe Tel: +353.21.244.6400
• India Tel: +91.80.43537383
• China Tel: +86.21.2407.1588
Visit www.macomtech.com for additional data sheets and product information.
M/A-COM Technology Solutions Inc. and its affiliates reserve the right to make
changes to the product(s) or information contained herein without notice.
Application Note
M570
Bonding, Handling, and Mounting Procedures for
Millimeterwave PHEMT MMIC’s
M/A-COM Products
Rev. V4
Curing of the epoxy should follow the manufacturer’s
recommended schedule. They epoxy must be cured in
air or oxidizing atmosphere since the reaction requires
oxygen. The epoxy oven should be clean and have
good air flow. The epoxy will not cure well if there are
other solvent fumes in the atmosphere.
Visual Inspection
Die down bonds should be checked with a 5-15X micro-
scope and should meet the visual criteria shown in Table
2.
Top Contacting Methods
The carrier fluid must not be allowed to flow on the top of
the chip. Not only will it make the chip un-bondable, it
will be almost impossible to detect under normal bonding
procedure. If a vacuum tip is used to put the chip in
place, remove the vacuum when the chip is 10 mils from
the epoxy. Static charge will hold the chip to the tip. If
the vacuum tip touches the epoxy, it will become coated
with the epoxy carrier fluid and contaminate the next
chip. This same problem may occur with the use of
tweezers. The tweezers should be cleaned before pick-
ing up another chip if they touch the epoxy.
The usual criteria for choosing a specific top bonding
technique are the size of the top contact of the chip, the
type of chip, the sensitivity of the chip to temperature
and pressure, the type of circuit board, and the equip-
ment available. Usually, the simplest contacts are a gold
0.0007 to 0.001 inch diameter wedge bonded gold wire.
The inductance of a 1 mil diameter wire will be ~0.5 nH
for a 0.20 inch long lead. This inductance can be re-
duced considerably by using multiple contact wires.
It is very difficult to give definite parameter values of
force pressure time and temperature for an optimum
bonding schedule. Different wire, bonding surfaces, or
die characteristics require different bonding conditions.
GaAs is very brittle and extra care should be taken when
wire bonding. In general, the bonding parameters should
be adjusted to maximize reproducibility at a high bond
pull strength.
The shear bond strength of a good epoxy joint can ap-
proach that of solder 50-100 kgms/cm2. The thickness
of the conductive epoxy should be kept at 0.001” or less.
The shear bond strength should be about:
40-60 grams for 0.010 x 0.010 inch chip
150-250 grams for 0.020 x 0.020 inch chip
350-500 grams for 0.030 x 0.030 inch chip
In general, the epoxy will shear before the chip breaks.
Weak bonds are usually caused by the use of old epoxy,
bonds that are too thick, or lack of cleanliness.
Visual
(Good Bond Criteria)
Typical Bond Strength
Extra RS1 From Die Down
(0.020” Chip)
Die Down Method
(In Stress)
Flat, maximum epoxy thickness
approx. 0.001 inch 90% min. wetting
Conductive Epoxy
Soft Solder
Approx. 50-100 kgms/cm2
Approx. 70-100 kgms/cm2
Approx. 100-150 kgms/cm2
Less than 0.1 ohms
Less than 0.1 ohms
Less than 0.1 ohms
Flat, maximum epoxy thickness
approx. 0.001 inch 90% min. wetting
Flat, maximum epoxy thickness
approx. 0.001 inch 90% min. wetting
Gold-tin Eutectic Solder
1. This is the approximate extra RF series resistance from an ideal lossless bond of a 0.020” x 0.020” chip.
Table 2. Visual Inspection for Good Die-Down Bonds (Using a 5-15x Microscope)
3
ADVANCED: Data Sheets contain information regarding a product M/A-COM Technology Solutions
is considering for development. Performance is based on target specifications, simulated results,
and/or prototype measurements. Commitment to develop is not guaranteed.
PRELIMINARY: Data Sheets contain information regarding a product M/A-COM Technology
Solutions has under development. Performance is based on engineering tests. Specifications are
typical. Mechanical outline has been fixed. Engineering samples and/or test data may be available.
Commitment to produce in volume is not guaranteed.
• North America Tel: 800.366.2266 • Europe Tel: +353.21.244.6400
• India Tel: +91.80.43537383 • China Tel: +86.21.2407.1588
Visit www.macomtech.com for additional data sheets and product information.
M/A-COM Technology Solutions Inc. and its affiliates reserve the right to make
changes to the product(s) or information contained herein without notice.
Application Note
M570
Bonding, Handling, and Mounting Procedures for
Millimeterwave PHEMT MMIC’s
M/A-COM Products
Rev. V4
Wedge bond with 1.0 mil diameter gold wire or 3.0 mil x
0.0005 mil ribbon and a force of 18 to 22 grams. Bonds
should be started on the die and terminated on the pack-
age, if possible. For RF connections, two wires are rec-
ommended. Most bonding pads are 4.0 x 4.0 mils and
most input and output pads are 4.0 x 4.0 mils.
Acceptable Bonds
Wire does not separate when tested
No fractures in bond
No separation of metallization
Wire breaks before bond
Most problems are caused by improper bonding machine
and tool settings as well as improper maintenance and
cleanliness. It is important to control the movement of
the part being bonded, alignment of tools, tool height,
angle, and tool condition.
Unacceptable Bonds
Wire separates from bond
Bond fractures at weld
Separation of metallization from dice
In general, the die will crack or “crater” if too hard a wire
or excessive pressure is used. Too little pressure results
in small, weak bonds. A good wire bond should be
stronger than the wire and should also be two or three
times the wire diameter. When wire bonding, the de-
formed width of the wire should be about 1.3 to 1.8 times
the wire thickness. If the deformed width is too small,
the bond will tend to lift off. If it is too large (greater than
1.8 times the wire diameter) the wire tends to weaken
and break. Figure 2 shows the relationship between the
pull strength and the deformed width of the ultrasonic
bonded wire.
Wire or Ribbon Size
(inches)
Minimum Pull Strength
(grams)
0.0007 wire diameter
1.5
0.001 wire diameter
0.002 wire diameter
3.0
9.0
Table 3. Bond Strength Criteria (Gold Wire or Strap)
Figure 3.
Bond Strength Pull Test
It is extremely important to maintain good quality control
procedures in order to ensure good bonding. Figure 3
and Table 3 illustrate criteria for visual inspection and for
testing on bond strength.
Capacitors and Resistors
It is recommended that capacitors and resistors are
selected that meet at least the same temperature
ranges as the MMICs. The following are recom-
mended devices to use.
Figure 2. Pull Strength vs. Deformation for a
Wirebond
Capacitors
Dielectric Laboratories
100 pF
1000 pF
P/n D30BH101K5PK or equivalent
P/n D35BV102KPX or equivalent
Resistors
Mini-Systems, Inc.
10 WP/n MSTF-2ST-10R00J-G or equivalent
4
ADVANCED: Data Sheets contain information regarding a product M/A-COM Technology Solutions
is considering for development. Performance is based on target specifications, simulated results,
and/or prototype measurements. Commitment to develop is not guaranteed.
PRELIMINARY: Data Sheets contain information regarding a product M/A-COM Technology
Solutions has under development. Performance is based on engineering tests. Specifications are
typical. Mechanical outline has been fixed. Engineering samples and/or test data may be available.
Commitment to produce in volume is not guaranteed.
• North America Tel: 800.366.2266 • Europe Tel: +353.21.244.6400
• India Tel: +91.80.43537383
• China Tel: +86.21.2407.1588
Visit www.macomtech.com for additional data sheets and product information.
M/A-COM Technology Solutions Inc. and its affiliates reserve the right to make
changes to the product(s) or information contained herein without notice.
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