MICRONAS - Micronas Backend Overview
Summary
TLDRThe video script details the backend production process at Micronus, focusing on the meticulous testing and assembly of integrated circuits. It showcases the use of special equipment for parameter testing, probe cards for individual die testing, and the precise placement of components. The process includes dicing silicon wafers, bonding dice onto lead frames, and wire bonding. Quality control measures such as mechanical tests and statistical process control ensure reliability. The components are then molded, trimmed, and inspected, with final checks at extreme temperatures to simulate real-world applications. Each component is marked with a laser for identification, ensuring high-quality standards from Micronus.
Takeaways
- 📦 Silicon wafers are transported in dust-type boxes from the wafer fabrication facility to the backend production area.
- 🔬 A comprehensive testing process includes a parameter test to ensure the integrated circuit properties meet specifications.
- 📌 Individual die testing uses probe cards with up to 130 needles, precisely aligned to aluminum contact openings.
- 🎨 Defective ICs are marked with a small colored dot for later elimination.
- 🔄 Both digital and analog circuits are tested, with up to 500 tests required for a typical IC.
- ⚙️ The assembly area involves dividing tested wafers into individual dice using a dicing process with diamond-bladed saws.
- 🧲 Dice are bonded onto copper lead frames using an epoxy resin adhesive, which hardens in a furnace at 145°C.
- 🔗 Multi-chip assemblies require precise bonding and wire connections, with 276 individual wire connections applied in under 50 seconds.
- 🔬 Extensive quality inspections and statistical process control are used to maintain process parameters within specification limits.
- 🛡️ Components are molded with a plastic compound containing ultrafine glass particles to protect sensitive wire connections and prevent corrosion.
- 🔍 Post-molding, components undergo X-ray inspection to ensure the integrity of the gold wires and positioning.
- 🏷️ Each component is marked with a laser beam, including type, manufacturing date, and batch number for traceability and quality control.
Q & A
What is the first test conducted on the silicon wafers in the backend production process?
-The first test conducted on the silicon wafers is the parameter test, which ensures that the properties of the integrated circuit, such as specific transistor characteristics, comply precisely with the specifications.
How are the individual needles of the probe card positioned during testing?
-The individual needles of the probe card have to be accurately positioned on the aluminium contact openings, which are only about 100 micrometers in size.
What is done to mark defective integrated circuits during the testing phase?
-Defective integrated circuits are marked with a small colored dot on the wafer, which allows for their elimination at a later stage.
How many tests are typically necessary to check the digital and analog circuits in a micronus IC?
-In a typical case, 500 tests are necessary to check the digital and analog circuits in a micronus IC.
What is the purpose of the adhesive film used when mounting the wafers in a metal frame?
-The adhesive film ensures that the dice remain in their original position even after they've been sawn apart and that the wafer can be further processed in a reliable manner.
What is the width of the saw blades used in the dicing process?
-The saw blades used in the dicing process are fitted with minute diamonds and are only 30 micrometers wide.
How are the individual dice picked up after the dicing process?
-The individual dice are picked up by fully automatic machines with an integrated imaging system, which corrects any positioning errors.
What is the role of the copper strips in the assembly area?
-The copper strips, also known as lead frames, form the electric contact with the printed circuit board and are bonded onto the dice with an epoxy resin adhesive.
How is the electric contact between the aluminium contact surfaces on the dice and the fingers of the copper lead frame achieved?
-The electric contact is achieved through a thin gold wire, which is welded on by fully automatic wire bonders at a temperature of 200° C with the aid of pressure and ultrasonic energy.
What is the purpose of the plasma cleaning operation after the silver conducting adhesive has been hardened?
-The plasma cleaning operation serves to remove any organic contamination on the contact surfaces of the printed circuit board or the dice.
How is the quality of the components ensured during the molding process?
-Quality is ensured through extensive quality inspections, such as mechanical pull tests and statistical process control, which keeps individual parameters within specification limits.
Outlines
🔍 Quality Assurance in Micronus Wafer Fab
The script describes the meticulous quality control processes at Micronus's back-end semiconductor manufacturing facility. Wafers are tested for compliance with specifications using special test equipment and structures. A parameter test is conducted to ensure the integrated circuits' properties meet the required standards. Each die is individually tested using probe cards with precision alignment on tiny contact openings. Defective ICs are marked and later eliminated. The wafers are then divided into individual dice using a dicing process with diamond-coated blades. The dice are picked up by machines with imaging systems to correct any positioning errors. Defective dice are left on the adhesive film, while the rest are bonded onto copper strips for electrical contact with the printed circuit board. The process involves both in-house and purchased memory chips, with a high level of precision and quality control to ensure customer satisfaction.
🔧 Backend Production Process at Micronus
This paragraph details the backend production process at Micronus, where expert employees and advanced equipment work continuously to ensure quality. After the adhesive is hardened, a plasma cleaning operation removes organic contamination from the contact surfaces. Electric contact is established through gold wire bonding, which is applied by automatic machines at high temperatures and with ultrasonic energy. Quality inspections are conducted, including mechanical tests and statistical process control to maintain parameters within specification limits. Components are molded with a plastic compound under high pressure to protect the wire connections and prevent corrosion. The molding compound is made of a thermoset material with ultrafine glass particles to minimize thermal expansion differences with the silicon dice. The molded components are inspected using an X-ray microscope to confirm the integrity of the gold wires. The copper lead frame's leads are then cut in a stamping process to separate the components.
🛠 Final Processing and Quality Checks at Micronus
The final steps in Micronus's production process involve electrochemically plating the copper lead frame to facilitate further processing by customers. The electroplated leads are then trimmed and shaped before being separated into transport trays. Micronus conducts comprehensive checks to ensure the functionality of both digital and analog circuits at various temperature ranges, simulating real-world operating conditions. Components that fail to meet specifications are scrapped. Each component is marked with a laser beam, indicating type, manufacturing date, and batch number for identification and traceability. Before storage, a complex imaging system checks the leads against package specifications to ensure they are suitable for automated customer processing. The process concludes with a commitment to delivering high-quality soldered joints and components.
Mindmap
Keywords
💡Multichip
💡Parameter Test
💡Probe Cards
💡Dicing
💡Lead Frame
💡Wire Bonding
💡Molding Compound
💡Plasma Cleaning
💡Quality Inspection
💡Coefficient of Thermal Expansion (CTE)
💡Laser Marking
Highlights
Micronus uses dust-type boxes for transporting processed silicon wafers from the wafer Fab.
Wafers undergo comprehensive testing with special equipment to ensure circuit properties meet specifications.
Parameter tests are conducted using test structures to monitor process parameters in the wafer Fab.
Individual die testing is done with probe cards containing up to 130 needles for precise electrical contact.
Defective ICs are marked with colored dots for later elimination.
Most micronus ICs require 500 tests, conducted in under three seconds.
Wafers are mounted in metal frames with adhesive film for dicing into individual dice.
Dicing process uses saw blades with minute diamonds, turning at over 30,000 rotations per minute.
Automatic machines with imaging systems pick up dice, correcting any positioning errors.
Defective dice are left on the adhesive film, while others are bonded onto copper strips.
Copper strips form the electric contact with the printed circuit board, also known as lead frames.
Silver conducting adhesive with silver particles is used for bonding and hardened in a furnace.
Multichip assembly involves bonding additional dice onto the printed circuit board with high precision.
Gold wire, only 25 micrometers thick, is used for electric contact between dice and lead frame fingers.
Quality inspections include mechanical tests and statistical process control to maintain parameter limits.
Components are molded with a plastic compound containing ultrafine glass particles to match thermal expansion.
Molding compound quality is critical for long-term reliability of the finished components.
X-ray microscope inspection confirms that molding has not affected the position of gold wires.
Leads of the copper lead frame are electrochemically plated for further processing by customers.
Components are subjected to temperature tests simulating minimum or maximum operating conditions.
Each component is marked with a laser beam containing type, date of manufacture, and batch number.
Final quality check ensures leads correspond precisely to package specifications for automatic customer processing.
Transcripts
back end at micronus taking the example
of multichip
[Music]
production the ready processed silicon
Wafers are supplied in dust type boxes
from the micronus wafer Fab next door
all the Wafers are now put through a
comprehensive range of tests with the
aid of special test
equipment first of all the so-called
parameter test is conducted this is
performed with test structures specially
generated for the purpose which are
arranged between the actual dice the
parameter test makes sure that the
properties of the integrated circuit
such as specific transistor
characteristics comply precisely with
the specifications this test thus
monitors the process parameters imployed
in micron's wafer Fab the next test is
conducted on each individual die on the
wafer the electrical contacts are made
with so-called probe cards which contain
up to 130
needles the individual needles have to
be accurately positioned on the
aluminium contact openings which are
only about 100 micrometers in size
defective ic's are marked with a small
colored dot on the wafer and eliminate
it at a later stage most micronus ic's
contain both digital and analog circuits
in a typical case 500 tests are
necessary to check these ic's tests that
are conducted in less than three
[Music]
seconds in the assembly area the tested
Wafers now have to be divided up into
individual
[Music]
dice first of all the Wafers are mounted
in a metal frame with the aid of an
adhesive film only 70 microm
[Music]
thick
the film that's clamped in the Metal
Frames ensures that the dice remain in
their original position even after
they've been swn apart and that the
wafer can be further processed in a
reliable
[Music]
manner the wafer is now aligned fully
automatically and cut into individual
dice with saw blades process also known
as
dicing the S blades are fitted with
minute diamonds and are only 30 micromet
wide they turn at more than 30,000
rotations per
minute deionized water is used to cool
the sore blade and to remove the Silicon
dust that's
[Music]
created
[Music]
the individual dice are picked up by
fully automatic machines with an
integrated Imaging system and any
positioning errors are
corrected the defective dice previously
marked with a small colored dot or the
defective printed circuit board in the
case of multichip assembly are left on
the adhesive
film the remaining dice or in this
particular case a small printed circuit
board are bonded onto copper strips with
an epoxy res
[Music]
adhesive these copper strips
subsequently form the electric contact
with the printed circuit board they're
also known by the technical term of lead
frames the silver conducting adhesive
which is filled with silver particles is
hardened for 45 minutes in a continuous
furnace operating at 145°
[Music]
C
in multichip assembly two further dice
are now bonded onto the printed circuit
board in a further bonding
operation one of the dice comes from the
micrones wafer Fab and is processed as a
diced wafer in the manner already
[Music]
described
the second die is a memory chip that has
been purchased it's been fully tested
and is supplied on surf
[Music]
tapes the fully automatic machine
employed for this process is able to
process both dice at one and the same
time and position them with a degree of
precision in excess of 25
[Music]
micromet to ensure the necessary high
quality is achieved in the elaborate
process steps performed in backend
production expert employees and state
of-the-art equipment work Right Round
the
[Music]
Clock after the silver conducting
adhesive has been hardened once again
during a second run through the furnace
a plasma cleaning operation takes place
this serves to remove any organic
contamination on the contact surfaces of
the printed circuit board or the
[Music]
dice the electric contact between the
aluminium contact surfaces on the dice
and the fingers of the copper lead frame
is achieved through a thin gold wire
wire this is welded on by fully
automatic wire bonders at a temperature
of 200° C with the aid of pressure and
ultrasonic
energy a multi-chip requires 276
individual wire connections which are
applied in less than 50
seconds
[Music]
[Music]
the gold wire which is only 25
micrometers thick ensures a perfect
electric
contact to ensure that any deviations in
the process are detected as early on as
possible extensive quality inspections
are carried out such as this mechanical
pool
test statistical process control is used
to keep the individual parameters within
the specification limits on the basis of
so-called control charts any deviations
from the set point values are detected
in this way and can be corrected without
delay this guarantees liability which in
turn ensures that we meet our customers
quality
demands
[Music]
to protect the sensitive wire
connections from mechanical damage and
to prevent the Silicon Dice from
corroding through moisture all the
components are molded with a plastic
compound under high pressure at a
temperature of 175°
C the plastic compound used is a
thermoset which contains more than 80%
ultrafine glass particles as a filler
this ensures that the difference between
the coefficient of thermal expansion of
the molding compound and the Silicon Dy
is kept as small as possible the quality
requirements placed on the molding
compound in terms of processibility
Purity and specified mechanical
properties are extremely high they
ensure that the finished components will
operate reliably over a very long period
of
[Music]
time
when the molded component is inspected
in an x-ray microscope a highly enlarged
shadow image of the Interior is seen
this serves to confirm that the molding
operation has not changed the position
or course of the fine gold
[Music]
wires after the molding operation the
individual leads of the copper lead
frame are still all connected to each
[Music]
other this so-called Dam bar is now cut
in a stamping
[Music]
process
[Music]
the surface of the copper lead frame
that's still bare is now
electrochemically plated in The Next
Step this ensures that the finished
components can then be further processed
by the customer without any
[Music]
problems
the electroplated leads now have to be
trimmed to the right length and given
their final shape in a number of
different forming
[Music]
stages after this the individual
components are separated and placed in
transport
[Music]
trays
micronus then conducts another full
check to ensure that the digital and
analog circuits on all the finished
components are working perfectly this
check is conducted at -45° C at ambient
temperature and at plus 95° C depending
on the
requirements these values simulate the
minimum or maximum operating temperature
of the components that can occur in a
subsequent application of the
customers
components that don't comply with all
the specified properties such as if
electrical parameters have been
adversely affected through the molding
process are eliminated after this
process step and
[Music]
scrapped
[Music]
as the final step each component is
marked with a laser
beam this inscription contains the type
date of manufacturer and the batch
number it's also used for precise
identification in the event of a
customer
[Music]
complaint before the components are
taken to the sales Warehouse a check is
conducted with a complex Imaging system
to ensure that the leads correspond
precisely to the package
[Music]
specification this ensures that our
customers can further process the
products we deliver by predominantly
automatic means and above all it means
that the solded joints we Supply are all
perfect
quality from
[Music]
micronus
5.0 / 5 (0 votes)