In the glossary, we introduce basic terms for robots in clean rooms.
You can learn fundamental knowledge here.
An actuator is a driving device that transforms energy (electricity, air pressure, oil
pressure, magnetic force, etc.) into some kind of mechanical movement, such as linear
motion or rotation.
An aligner is a device that aligns the center of semiconductor wafers and the direction
of their notches.
Positions the center of wafers and the direction of their notches.
Since positional misalignment between wafers, equipment, and tables can cause defects
and decrease productivity, it is necessary to position the wafers and align the
direction of their notches correctly.
A robot that performs work in an atmospheric environment in a clean room. The robot is
equipped to take measures such as minimizing the dust generated due to the wear of
Back-end process is to grind the back side of wafers having been fabricated in the
front-end process to make them thinner. Next, LSI is diced into chips and bonded to
packages, on which wiring, molding, and other processing as well as inspection are
performed to complete CPU, DRAM, and other semiconductors.
Backlash refers to a “clearance” or “play” intentionally provided in the direction of
motion for gears to make movements as they are engaged. When an object rotating in a
certain direction is turned in the opposite direction, positional misalignment, impact,
or vibration may occur, which will cause deterioration in the positioning accuracy of a
wafer transfer. The smaller the numerical value of backlash, the smaller the difference
similar to a dead band.
A clean room is a room in which the air is kept in an appropriate condition by imposing
a restriction on the number of microparticles included in the air. Cleanliness can be
understood with a particle counter that can measure the number of particles in the air,
and cleanliness is classified into levels according to each standard, in which criteria
have been established.
Although classification was unified into ISO Standards in November 2001 and afterward,
the old FED (US Federal Standards) is still conventionally used in Japan. The
cleanliness in ISO Standards is classified into Class 1 to Class 9, where the
cleanliness is determined by the number of particles of 0.1μm or more included in the
air per cubic meter.
For example, Class 1 means that the number of particles of 0.1μm is 10, and Class 2
means that the number of particles of 0.1μm is 100. The smaller the class, the higher
the performance. It is important to introduce clean room(s) of a class ideal for
manufactured products and production processes. For semiconductor manufacturing
factories, clean rooms of Class 3 to 5 (based on the ISO Standards) are ideal, which
correspond to Class 1 to 100 in the FED Standards.
Cylindrical coordinate robot
This robot has arm(s) that can make up-and-down movements and work at different heights,
and extend and retract, and also has a rotation axis that can rotate 360 degrees. It is
often used for transfer of liquid crystals and semiconductors, taking advantage of its
wide range of motion.
Manufacturers of semiconductor devices, such as CPUs and DRAMs are called device makers.
Using the semiconductor manufacturing equipment introduced for procured bare wafers,
semiconductor devices are manufactured with various types of liquids, gases, and
Refers to the process of cutting the integrated circuits formed on a wafer into chips
with a dicing blade (circular blade) (dicer method). There is also a laser dicing method
where wafers are split by laser light into chips.
Integrated circuits formed on a wafer are cut into small rectangular chips using a
dicing blade (circular blade) and each chip is called a die. It is also called an LSI
chip and several tens to hundreds of dies are made on one wafer.
Metal terminals, etc., are attached to these chips (wire bonding), which are packaged
(molded) with resin. Recently, there are cases where chips are directly mounted on
printed circuit boards, etc., without packaging (Chip on board method).
Direct drive motor
A kind of servomotor that enables improved rigidity of the power transmission system and
high-speed precision drive due to its backlashless feature since it is directly coupled
without using intermediate mechanisms, such as a speed reducer, belt, etc. Loss by
friction of reduction gears can also be minimized, and furthermore, space can be saved
and mechanical noise can be eliminated.
FC-BGA is an abbreviation for Flip Chip-Ball Grid Array. A FC-BGA substrate is a
high-density-packaged substrate to realize speeding-up of advanced devices (CPU, GPU,
Edge clamp (edge grip)
Refers to a mechanism that transfers wafers while holding their perimeters. Wafers are
transferred while being caught by multiple holding claws without making contact with the
wafer surface. Mainly, it is used for placing/removing wafers into/from the container,
positioning, and transporting wafers.
EFEM is an abbreviation for Equipment Front End Module. For EFEM, an atmospheric
transfer robot and aligner are installed in the frame equipped with an FFU (fan filter
unit), and this module equipment has load port(s) to deliver FOUP(s) in front. It is
installed in front of the process equipment.
A general term that refers to malfunctions and failures caused by electromagnetic waves
derived from signals transmitted from electronic circuits through conductors, or signal
leakage due to electromagnetic noise emitted by electronic devices. It may also refer to
electromagnetic energy that impairs the performance of telecommunications equipment.
An end effector is mounted at the fore-end of a wafer transfer robot and is used for
In the semiconductor industry, it is also called a hand, pick, blade, or tweezers.
What the term “end user” means varies depending on status. From the standpoint of a
robot manufacturer that sells wafer transfer robots, direct customers are equipment
manufacturers, and end users are device makers. In this case, end users do not include
electronics device manufacturers that manufacture TVs and other devices through the
fabrication of printed circuit boards with use of semiconductor devices.
Semiconductor manufacturing equipment manufacturers or FPD manufacturing equipment
manufacturers are called equipment manufacturers for short.
FA (factory automation)
A general term that refers to systems to automate production processes. Promoting
automation with machines can dramatically increase productivity, reduce human errors
during work, improve safety, and also cut production costs and stabilize product
quality. In addition, it strengthens a manufacturer's earning power.
FFU (fan filter unit)
An FFU refers to a unit that incorporates a fan and a high-performance dust-proof filter
as a set in a housing. As it is installed on the ceiling of an EFEM, the air suctioned
by the fan is cleaned by the filter and discharged as clean air. In addition, the FFU is
often installed on the ceiling of a clean room or clean booth and it can be used in
spaces that differ in size for each manufacturing process by changing the installation
location and the number installed.
FOUP (Front Opening Unified Pod)
A FOUP refers to a wafer storage cassette (pod) that is standardized by SEMI, an
industry group of semiconductor equipment manufacturers. It is an enclosed cassette
mainly for 300mm wafers to transfer wafers to another process by OHT and store wafers in
semiconductor factories. A FOUP has an opening and closing mechanism in front of the
container, and an interface section (load port) to place/remove wafers into/from
semiconductor manufacturing equipment.
A FOUP cassette is a container that stores 300mm wafers.
FPD is an abbreviation for Flat Panel Display. For PC monitors of the Showa Period,
cathode-ray tubes (CRTs) were used, but in the 1990s, a transition was made from desktop
PCs to laptop PCs and then to notebook PCs to make PCs portable. What played an
important role at that time was FPDs. With changes from monochrome screens to color
screens, screens have become thinner to reduce weight, larger in size, and sharper.
Currently, LCDs (liquid crystal displays) and OLEDs (organic EL displays) are
Refers to a process to make hundreds of ICs or LSIs by using various types of process
equipment on bare silicon wafers made in the wafer manufacturing processes.
A wafer transfer robot is installed in semiconductor manufacturing process equipment,
where wafers are transferred to desired locations upon receipt of motion commands from
the controller called a host that controls the entire equipment. The host and robot are
connected by TCP/IP, to which IP addresses are assigned. The act of operating the
equipment upon receipt of motion commands from the host connected is called host
LCD is an abbreviation for Liquid Crystal Display.
Magnetic fluid seal
A magnetic fluid seal is used as a vacuum seal that blocks a vacuum from the atmosphere
by applying the principle of cutting off the flow of air by incorporating an iron-made
rotating shaft and N and S circular magnets in the cylindrical housing surrounding the
shaft, and putting a magnetic fluid in the doughnut-shaped space by using its property
of being attracted to the magnets.
A transfer robot that works in a clean room with excellent airtightness and dust
resistance, and transfers individual substrates mainly in a vacuum chamber. The robot is
equipped to take measures against dust, gas generation, lubricating oil, and heat
Refers to the maximum mass a robot arm can lift up. It includes not only the object to
be carried but also the weight of the hand. It is necessary to check the payload
described in equipment specifications.
MEMS is an abbreviation for Micro Electro Mechanical Systems, referring to microdevices
including sensors integrated with circuits and actuators, etc., on semiconductor
substrates. MEMS are mostly devices that realize miniaturization, labor-saving, and cost
reductions, which are used in a wide range of fields, such as automobiles, information
equipment, home appliances, and medical devices, as well as in biotechnology, and it is
said that further miniaturization will provide greater cost advantages.
NL (normal liter)
If measured under the conditions of an atmospheric pressure of 0.1013MPa, temperature of
0°C, and relative humidity of 0%,
1NL = 1.0L (atmospheric pressure: 0.1013MPa, temperature: 0°C, and relative humidity:
0%) results, but in a general environment (temperature: 20°C and relative humidity:
65%), 1NL ≈ 1.079L (atmospheric pressure: 0.1013MPa, temperature: 20°C, and relative
humidity: 65%) results.
For positional alignment in the crystal orientation, the perimeters of wafers are
V-notched. Conventionally, an orientation flat would be formed on up to 8-inch wafers,
but in order to increase the number of chips manufactured, 8-inch and 300mm wafers are
An OLED refers to a display using organic light-emitting diodes. Since light is emitted
by applying voltage to the light-emitting element, it does not require a backlight like
an LCD, and high brightness and contrast can be output with low power consumption.
Orientation flat refers to a flat portion formed by linearly cutting part of a disk in
order to indicate the crystal orientation of each wafer. Mainly, small-diameter wafers
from 2-inch to 6-inch come with an orientation flat.
For wafers from 8-inches, a V-notch is mainstream, and for 12-inch wafers, only a notch
In recent years, in the packaging process included in the back-end process, efforts have
been made to promote high integration by evolving the packaging technology based on
Moore's law. Specifically, it is the 3D packaging technology to integrate a CPU,
memory, etc., into the same package.
Particles mean nano-level dust in wafer manufacturing processes. These particles occur
due to wafer processing, machine rubbing, wafer rubbing against the wafer placement
surface when transferred, etc. Once nano-level particles are mixed on wafers, the wafers
become defective, causing yield reduction. Therefore, reducing particles to the extent
possible is important in semiconductor manufacturing processes.
Defined as the wafer transfer height. Formerly, there were cases in which no Z-axis was
mounted on wafer transfer robots that work in vacuum chambers. Due to the absence of the
Z-axis, it was sometimes necessary to align the height of each stage to reliably
transfer wafers. So, the transfer height would be determined by applying the concept of
path line. Currently, a robot with a Z-axis can absorb variations in transfer height.
A PLC (Programmable Logic Controller) is called a sequencer. In the semiconductor
industry, there are cases where the PLC is used as a higher-order system, and it is
connected with lower-order systems mainly by I/O and used as parallel control.
An actuator is operated to stop at a target position, and the allowable limit value
(absolute value) of the difference between the target position and actual stop position
This measurement is taken at each point within range from the origin to the maximum
stroke, and the maximum difference among the obtained values is shown as the value of
Repeatability (positioning accuracy)
The operation of stopping at an arbitrary point is repeated seven times from the same
direction, and the position is measured to obtain the difference between the maximum and
minimum values of the stop position. This measurement is conducted at the center and
both ends of the maximum stroke, and 1/2 of the maximum difference among the obtained
values with a plus-minus sign (±) is taken as repeatability.
SCARA is an abbreviation for Selective Compliance Assembly Robot Arm, and a robot with
SCARA is called a SCARA robot. The number of axes is four or more, and when comparing
SCARA to the human arm, there are rotation axes at the shoulder, elbow, and wrist
sections, and furthermore, there is an axis that raises and lowers the arm section.
While a cylindrical coordinate type robot can only transfer wafers in a radial fashion,
a SCARA robot can transfer wafers freely within the arm's reach. For this reason,
teaching work becomes intuitively difficult to understand and becomes complicated,
requiring rules to be established.
A servomotor is a motor that is used to control position, speed, etc., and is comprised
of a controller, driver, and encoder (rotation detector). It is an important component
as a constituent element of industrial machines that perform ultraprecision control at
high speed. Currently, AC servomotors that are operated by alternating current are
mainstream. Stepping motors, coreless motors, and DD (direct drive) motors are included
in the servomotor.
DAIHEN offers the UT-VDX3000NS series that significantly reduces vibration during arm
operation with the adoption of a gearless DD (direct drive) motor that enables high
acceleration and high-precision positioning.
SEMI is an abbreviation for Semiconductor Equipment and Materials International. It was
established in 1970, and its bases are located in various countries, mainly in the US
(headquartered in California). The SEMI establishes self-imposed standards for the
semiconductor manufacturing equipment industry as SEMI Standards. Therefore, when using
semiconductor manufacturing equipment, designs must be based on the standards set by the
The Japanese Industrial Standards JIS Z 8116:1994 defines sequence control as “a control
method to proceed with each step of control sequentially according to a predetermined
order or procedure.”
For sequence control, there are three basic actions: (1) order control, (2) time
control, and (3) condition control, which are controlled by a PLC system. For
programming, there are many cases where ladder logic is used because it can be used like
drawing an electrical diagram.
Si (silicon) wafer
Silicon wafers are manufactured by slicing cylindrical ingots of silicon to 1mm or less
in thickness, on which semiconductor elements are formed. Since Si wafers manufactured
to be of high purity with almost no impurities are extremely brittle due to their
crystallinity, they are mostly handled by robots that can work automatically without
SiC (silicon carbide) wafer
SiC (silicon carbide) is a compound of silicon (Si) and carbon (C), and semiconductors
using this are called compound semiconductors. With the expectation that SiC will lead
the next generation in place of silicon, demand for SiC is rapidly increasing as a
next-generation power semiconductor material. SiC features efficient power conversion
and excellent thermal conductivity compared with silicon, which can achieve
energy-saving and significant miniaturization of equipment including cooling mechanisms.
A solar panel is a square panel to facilitate the installation of devices that convert
sunlight into electrical energy. Solar panels are manufactured by applying the
semiconductor device manufacturing process and FPD manufacturing process.
Refers to the function of equipment or software that works on its own without depending
on other devices, systems, and resources. There are cases where a stand-alone is adopted
in order to avoid the risks of virus infection and information leakage through network
Refers to the time taken to manufacture one product, which is often used when setting
Specifically, it can be obtained by the following formula:
Takt time (time/piece) = Operating time ÷ Production planning quantity
The shorter the takt time, the more products can be produced with respect to the
operating time. The time necessary for work processes is calculated, aiming for
standardization of production lines according to the quantity needed.
To operate a robot, it is necessary to “teach” desired operating positions in advance. A
teach pendant is a kind of remote control device with which numerical values are input
to make the robot perform the same operations as actual work to store the positions and
angles of joints and terminal ends while making fine adjustments. Storing desired
operating positions while moving the robot at low speed with use of the teach pendant
(teaching pendant) is called online teaching.
Teflon is a registered trademark of DuPont in the US, and its chemical name is PTFE
(polytetrafluoroethylene). Since semiconductor manufacturing processes require extremely
clean environments, Teflon coating excellent in heat resistance, non-adhesiveness,
weather resistance, chemical inertness, etc., is used for semiconductor manufacturing
equipment and also for wafer cassettes.
Refers to a workload that can be processed per unit time, and in other words, a
production volume per unit time. On a manufacturing site, if the production volume is
increased and the lead time is reduced by an increase in processing speed, it can be
said that the production efficiency has been raised and throughput has improved.
Vacuum is categorized into five levels by pressure range as follows:
- Low vacuum: 105Pa - 102Pa - Medium vacuum: 102Pa - 10-1Pa
- High vacuum: 10-1Pa - 10-5Pa - Ultra-high vacuum: 10-5Pa - 10-8Pa
- Extremely high vacuum: 10-8Pa or less *Pa: pascal *1 atm = 101325Pa
When plasma is generated in semiconductor manufacturing processes (exposure to light,
forming a film, etching, sputtering, etc.), a vacuum state is required, in which a high
quality vacuum environment of the ultra-high vacuum level having a low boiling point
with few minute impurities becomes necessary.
A wafer placed on the end effector in an atmospheric environment is gripped by a vacuum
chuck, and is transferred to a target position without positional displacement. Vinyl
piping is laid and connected to the end effector through the robot body from the bottom
of the robot, and a vacuum source is connected from the factory to the vacuum connection
port at the bottom of the robot. During wafer transfer, the robot controller operates
the solenoid valve that opens and closes the vacuum source by corresponding signals to
grip and release the wafer.
Wafers are disk-shaped thin slices of cylindrically processed ingots of high-purity raw
material/substance (e.g. single-crystal silicon).
In manufacturing processes, fine wiring, elements, and other circuit patterns are formed
on their surfaces by masking, exposure to light, etching, and other processing, and the
grid-like circuit patterns arranged in an orderly manner are transferred. By dicing
them, rectangular dies (semiconductor chips) can be taken out. In the case of general
silicon wafers, their outer sizes are standardized by industry groups, and their
perimeters are notched to align the orientation of the wafers.
Checks in which slot of a cassette contains a wafer and whether there are any errors,
such as double wafers or cross-slotted wafers, and also checks if positional information
of slots is consistent.
Wafers in the cassette are irradiated with a light source (laser light, LED light),
while mechanically moving up and down, and the presence or absence of wafers/slot
positions are understood on the basis of whether the transmitted or reflected light is
detected. There are also cases where wafer mapping is carried out while the light source
is mounted on a robot.