月: 2023年1月

What Is Cyclohexanone?

Cyclohexanone is an organic compound with the molecular formula C6H10O. It is a cyclic ketone with one methylene group of cyclohexane replaced by a carbonyl group. It is also known as ketohexamethylene, pimelic ketone, cyclohexyl ketone, hexanon, etc. Its CAS registration number is 108-94-1.

The Beckmann rearrangement of cyclohexanone oxime also produces caprolactam, an intermediate in the manufacture of 6-nylon and 6,6-nylon.

Uses of Cyclohexanone

The main uses of Cyclohexanone are as follows:

• Raw material for caprolactam, adipic acid, and nylon
• High boiling point solvent for celluloid, fats, waxes, rubber, synthetic resins, resin lacquers, etc.
• Stripping agents for paints and varnishes

In particular, the majority of applications are as raw materials for 6-nylon and 6,6-nylon. It is sometimes used as a solvent or as an activator for oxidation reactions.

Properties of Cyclohexanone

Cyclohexanone has a molecular weight of 98.14, a melting point of -32.1 °C, and a boiling point of 156 °C. It is a colorless liquid with a characteristic odor at room temperature. It is said to have an odor similar to that of camphor-like acetone. If left for a long period of time, it oxidizes and turns yellow.

It is extremely soluble in ethanol and diethyl ether and slightly soluble in water. Its density is 0.9478 g/cm3.

Types of Cyclohexanone

The types of cyclohexanone generally available include reagent products for research and development, industrial chemicals, and fine chemicals. R&D reagent products are often used as raw materials for organic synthesis and as solvents.

The capacities include 500 mL, 15 kg, 17 kg, etc. These products are sold in relatively large capacities among reagent products.

In industrial products such as industrial chemicals and fine chemicals, it is offered in oil cans (16 kg), drums (190 kg), containers (1,000 L), and other packing formats.

Other Information on Cyclohexanone

1. Synthesis of Cyclohexanone

Several methods for synthesizing cyclohexanone have been reported, the first of which is the oxidation of cyclohexanone. This reaction is catalyzed by cobalt or manganese acetates or naphthenates. A mixture of cyclohexanone and cyclohexanol is formed, which can be separated by distillation if cyclohexanone is to be isolated.

Other methods include dehydrogenation of cyclohexanol at 400-450°C using a zinc or copper catalyst and hydrogenation of phenol at 140-170°C in the gas phase using a palladium catalyst such as Pd-CaO/Al2O3.

2. Synthetic Reaction of Nylon Raw Materials

One of the useful chemical reactions of cyclohexanone is the synthesis of nylon raw materials.

ε-caprolactam, the raw material for 6-nylon, is synthesized as follows:

• Condensation with hydroxylamine to form cyclohexanone oxime.
• The intermediate obtained in the above reaction is converted to ε-caprolactam through the Beckmann rearrangement reaction

Ring opening also occurs by the reaction of a mixture of cyclohexanone and cyclohexanol with nitric acid oxidation, resulting in the synthesis of adipic acid. Adipic acid is a substance used as a raw material for 6,6-nylon.

3. Reactivity of Cyclohexanone

Cyclohexanone is a stable substance under normal storage and handling in accordance with regulations. There is a risk of fire or explosion when reacting with strong oxidizers such as nitric acid.

When storing, it is necessary to avoid mixing with such strong oxidizers. At temperatures above 44°C, an explosive vapor/air mixture may be generated. 

4. Safety Information on Cyclohexanone

Cyclohexanone is a highly flammable liquid/vapor with a flash point of 44°C (sealed). In terms of toxicity to the human body, it is toxic in contact with the skin, toxic by inhalation, irritating to the skin, irritating to the eyes, suspected of causing genetic disorders, and causing damage to the respiratory and central nervous systems.

What Is Cyclopropane Gas?

Cyclopropane gas is a cycloalkane molecule consisting of three carbon atoms forming a simple ring, with each carbon atom bonded to two hydrogen atoms. It is a colorless gas at room temperature, with a melting point of -127°C and a boiling point of -33°C. Cyclopropane can be liquefied when pressurized to 4-6 atmospheres and dissolves in 2.7 times its volume of water, ethanol, or acetone.

Discovered by August Freund in 1881, its anesthetic properties were identified by Henderson and Lucas in 1929. Commercial use of cyclopropane as an anesthetic began thereafter, with industrial production starting in 1936.

Uses of Cyclopropane Gas

Cyclopropane gas was previously used as an anesthetic due to its rapid induction of anesthesia when inhaled. It is a non-irritant, sweet-smelling agent. However, its use entailed risks such as a drop in blood pressure (cyclopropane shock) and arrhythmia during continuous anesthesia, limiting its use to anesthesia induction only. Additionally, when mixed with oxygen, cyclopropane poses an explosion risk. Due to these safety concerns, it is no longer widely used.

What Is Salicylamide?

Salicylamide is a white crystalline or crystalline powder aromatic compound. Its IUPAC name is 2-hydroxybenzamide, and it is also known as o-hydroxybenzamide.

Its chemical formula is C7H7NO2 and its molecular weight is 137.14. The CAS registration number is 65-45-2.

Salicylamide is obtained by amidation of methyl salicylate with ammonia in a nucleophilic substitution reaction.

Uses of Salicylamide

Salicylamide is a non-steroidal anti-inflammatory drug that reduces fever, swelling, and pain. Its antipyretic and analgesic effects are similar to those of aspirin.

It has been used in many over the counter drugs as an orally administered nonsteroidal anti-inflammatory drug, but is rarely used today.

Non-steroidal anti-inflammatory drugs inhibit the production of substances (prostaglandins) produced by the body that cause pain, fever, and inflammation. The inhibitory effect of prostaglandin production can relieve pain and reduce inflammation, but it cannot cure the cause of the pain, fever, or swelling itself.

Properties of Salicylamide

Salicylamide is a solid at room temperature with a melting point of 140-144°C and a boiling point of 270°C. It is very soluble in N,N-dimethylformamide, soluble in ethanol, propylene glycol and sodium hydroxide solution, and slightly soluble in diethyl ether and dimethyl sulfoxide. It is not very soluble in water or chloroform.

It has a pH of 5, which indicates the degree of acidity or alkalinity, and an acid dissociation constant (pKa) of 8.37. The acid dissociation constant is a quantitative indicator of the strength of an acid; the smaller the pKa, the stronger the acid.

Other Information on Salicylamide

1. Side Effects

The following side effects have been reported with salicylamide:

• Abnormal platelet function
• May aggravate asthma
• May aggravate gastric ulcers and other peptic ulcers
• May affect kidney and liver function
• Stomach pain, abdominal pain
• Nausea
• Rash
• Urticaria

Avoid use in children with influenza, aspirin asthmatics, and patients with peptic ulcer.

2. Handling and Storage Precautions

Handling precautions
Avoid contact with strong oxidizers. Use in a draft chamber with local exhaust ventilation. Wear personal protective equipment when using.

In case of fire
When burning, carbon monoxide, carbon dioxide, nitrogen oxides, etc. are produced. Use water spray, foam, powder extinguisher, carbon dioxide, extinguishing sand, etc. to extinguish fire.

In case of skin contact
Be careful not to get it on skin. Always wear protective clothing such as a lab coat or work clothes and protective gloves when using the product. Never roll up the sleeves of protective clothing to avoid skin exposure.

In the event of skin contact, wash off with soap and plenty of water. If on clothing, remove all contaminated clothing and isolate. If symptoms persist, seek medical attention.

In case of eye contact
Always wear protective glasses or goggles when using the product. In the unlikely event of eye contact, rinse carefully with water for several minutes. If you are wearing contacts and can easily remove them, take them off and rinse thoroughly. Seek immediate medical attention.

Storage
Salicylamide may be altered by light. When storing, place in a light-shielded glass container and keep tightly closed. Store locked up in a well-ventilated, cool place as far as possible, away from high temperatures and direct sunlight.

What Is Shearing Machinery?

Shearing machinery is a machine used to cut metal sheets into straight lines by shearing.

Shearing machinery is equipped with an upper blade and a lower blade.

Shearing is performed by mechanically applying pressure from above and below to the metal plate to be cut. Shearing machinery can be powered by either a mechanical or hydraulic source, which should be selected based on cost and maintenance requirements.

In recent years, turret punch press processing and laser processing have become more common, and the demand for shearing machinery is decreasing.

Uses of Shearing Machinery

Shearing machinery is used in sheet metal processing plants for cutting sheet metal. Depending on the model, some Shearing Machinery can cut even metal sheets as long as several meters. However, due to the limitation of the blade length, the cutting length is limited to about 6 meters.

Shearing machinery can be used to cut plates of materials such as stainless steel and steel sheets with metal sheets that fit within this size. For cutting longer metal sheets that cannot be handled by Shearing Machinery, laser cutting machines are generally used.

Principle of Shearing Machinery

Shearing machinery is similar to the principle of cutting paper with scissors that we use in our daily lives. The metal sheet to be cut is positioned where the blade of the Shearing Machinery will strike it, and then the upper blade descends to cut the sheet.

Shearing machinery can be classified into mechanical and hydraulic types, depending on the blade drive system.

1. Mechanical Type

In the case of the mechanical type, the blade is driven by a motor and clutch, and is characterized by its high cutting speed. Compared to the hydraulic type described below, the mechanical type is inexpensive, and since it does not use oil, maintenance is relatively simple. 

2. Hydraulic Type

The hydraulic type uses hydraulic pressure generated in the cylinder to drive the blade powerfully, resulting in high cutting performance. It can cut even relatively thick metal plates, which is difficult with the mechanical type. On the other hand, care must be taken to avoid problems such as oil leakage.

Other Information on Shearing Machinery

Points to Keep In Mind When Using Shearing Machinery

There are several points to keep in mind when using Shearing Machinery to produce high-quality products and to work safely.

Specific Usage

1. Adjusting the Clearance
Clearance in shearing machinery is the distance between the upper and lower blades. Even with scissors that we use in our daily life, paper cannot be cut well with scissors that have a large gap between the two blades.

For the same reason, in shearing machinery, the clearance between the upper and lower blades is important, and the size of the clearance makes a difference in the quality of the cut surface. If the clearance is too narrow, the load on the blade is too great and the blade wears easily, shortening the life of the blade.

Conversely, if the clearance is too large, the cut surface will have sagging and burrs. The appropriate clearance is determined by the material to be cut and the plate thickness, but in general, the appropriate clearance is approximately 6~10% of the plate thickness. 

2. Adjustment of Shear Angle
The shear angle is the opening angle between the upper and lower blades, just like the angle between two blades when scissors are opened. When the shear angle is large, or in scissors, when the scissors are wide open at the beginning of a cut, a small amount of force can be used to cut.

However, if the shear angle is too large, the cut material is prone to deflection (bow), twist (twist), and warp (camber). 

3. Do Not Cut Materials Over the Maximum Thickness
Shearing machinery has a maximum thickness limit. Cutting material that exceeds the maximum thickness will put a heavy load on the shearing machine, and in the worst case, may result in a breakdown.

When handling a shearing machine, you should check the maximum plate thickness and be careful not to cut any material that is thicker than the machine is capable of cutting.

What Is a Shrink Wrap Machine?

A shrink wrap machine hermetically seals various products with a transparent film.

Shrink-wrapping encases the product, offering protection and preventing contamination. It is particularly useful for bundling multiple items together, keeping them consolidated. The film also facilitates the application of stickers and labels.

Shrink wrap machines are categorized into partial or full coverage models. Partial coverage types include shrink labels, caps, and R-seals, while full coverage types comprise L-shrink and pillow shrink.

Uses of Shrink Wrap Machines

Shrink wrap machines are employed across various manufacturing sectors like food, cosmetics, and pharmaceuticals, where airtight packaging is essential. They are ideal for items such as meats, vegetables, bread, books, CDs, and DVDs, protecting them during transit.

These machines also play a crucial role in safeguarding products from scratches and dirt, while enhancing product design with labels and attachments.

For instance, PET bottles can be bundled together with shrink wrap for shipping.

Principle of Shrink Wrap Machines

Shrink-wrapping involves heating packaged goods as they move through a shrink tunnel. These tunnels, which can be steam or hot air types, uniformly heat the film. Steam tunnels offer higher thermal conductivity and a smoother finish, though may leave water droplets that require treatment. The hot-air method, especially the tornado shrink, directs hot air from multiple angles, closely matching the steam method’s finish accuracy.

For smaller batches or adjustments, heat guns and similar tools offer a manual alternative to these mechanical processes. Shrink-wrapping employs films that contract upon heating, typically made from polyester for its superior shrinkability.

Types of Shrink Wrap Machines

Shrink wrap machine types include dryer and tunnel models.

1. Dryer Type

The dryer method uses hot air to contract shrink film around the product. Products are first enclosed in shrink film, trimmed, sealed, and then subjected to hot air, typically in an industrial dryer, to shrink the film snugly around them.

2. Tunnel Type

In the tunnel method, products wrapped in shrink film are passed through a tunnel where hot air evenly contracts the film. This method tends to produce a more uniform shrink than the dryer method and includes steam, hot-air, and hot whirlwind (tornado shrink) variations for effective shrinking.

Similar to the dryer method, products are first enveloped in shrink film, trimmed, and sealed before shrinking in the tunnel.

How to Select Shrink Wrap Machines

Choosing the appropriate shrink-wrapping machine depends on specific needs and applications.

1. Dryer Type

With lower initial costs, the dryer type is suitable for startups and small-scale production. It’s compact and versatile for irregularly shaped products. However, it requires more time and effort for shrinking, with the potential for uneven results due to manual heat application.

2. Tunnel Type

This method is better suited for uniform shrinking and mass production, allowing precise heat control. It necessitates a larger investment and space for the machinery and is limited to products that fit within the tunnel.

What Is a Silicone Sealant?

Silicone sealant is a sealant that primarily uses silicone resin as its base component.

Used to fill joints and gaps in buildings, machinery, and vehicles, sealants ensure waterproof and airtight seals, often referred to as sealing or caulking. Though initially liquid, sealants harden upon application, acquiring rubber-like properties.

Silicone sealant stands out for its affordability relative to other types of sealants and is widely available at home improvement stores. It is notable for its exceptional durability and adhesion.

Uses of Silicone Sealants

Silicone sealants find broad application due to their versatile properties. Key areas include construction, automotive manufacturing, and home DIY projects. In construction, they seal window frames and bathroom joints to prevent water and air penetration. For home DIY, they are utilized for leak repairs and water prevention tasks.

Beyond ensuring waterproofing and airtightness in buildings, silicone sealants repair tile roofs, wiring, and termination components. Their resistance to cold, weather, and heat makes them ideal for use around glass, sashes, bathtubs, and kitchens.

Additionally, silicone sealant serves as an adhesive, particularly useful in construction for joining roof sections.

Principle of Silicone Sealants

Silicone sealant, applied as a liquid, cures to develop elasticity, sealing gaps effectively. Its composition includes silicone resin, fillers, cross-linking agents, and catalysts.

The curing process is initiated by the cross-linking agent reacting with air moisture, transforming into a component that binds the silicone resin molecules, thereby hardening the sealant.

The curing mechanisms of moisture-curing silicone sealants vary, including deoxime, alcohol, and acetic acid types, distinguished by their byproducts. Select based on the curing mechanism due to potential surface interactions.

How to Choose Silicone Sealants

Sealants extend beyond silicone to include acrylic, urethane, and butyl rubber-based options. Both one-component moisture-curing sealants and two-component systems requiring mixing are available.

Selection should be based on understanding each type’s characteristics:

1. Durability

The sealant’s longevity is critical, often indicated by the manufacturer’s usage expectancy.

2. Elasticity

For structures, especially wooden ones, sealants must accommodate temperature-induced expansion and contraction.

3. Color

The choice of color should blend with the application area, particularly in visible locations like bathrooms and kitchens.

Other Information on Silicone Sealants

1. Merits and Demerits of Silicone Sealants

Merits:
Silicone sealants excel in heat and cold resistance, drying time, and adhesion, allowing for rapid installation without primers.

Disadvantages:
They cannot be painted over due to silicone oil surfacing, which repels paint and attracts dirt, compromising appearance. This limitation generally restricts their use to interior surfaces.

2. Modified Silicone Sealant

Despite the similar name, modified silicone sealants differ significantly in composition, allowing them to be paintable post-application but offering less durability. Understanding these differences is crucial to avoid confusion during purchase.

What Is a Cutter Clearance Gauge?

A cutter clearance gauge is a rectangular-shaped plate that is inserted into a gap between parts or products to measure the size of the gap. It is sometimes called a thickness gauge. The term “thickness gauge” is also used for a measuring instrument that measures the thickness of an object by pinching it, so care should be taken not to confuse the two. A single thin plate is called a leaf, and a bundle of several leaves of different thicknesses is called a combination leaf.

Uses of Cutter Clearance Gauges

Cutter clearance gauges are used to measure narrow gaps that cannot be measured with calipers. Basically, they are suitable for measuring the clearance between parallel surfaces, and cannot measure the clearance between cracks, for example. It is used to measure the skimmer between the base of a unit when assembling it, between a door and the door frame, between a reference position and a part when installing and adjusting a part, and between a piston and a cylinder. There are both metric and inch types of cutter clearance gauges. Metric cutter clearance gauges are commercially available in thicknesses from 0.01mm leaf. The use of cutter clearance gauges makes it possible to measure small gaps that cannot be measured with other tools.

Features of Cutter Clearance Gauges

Cutter clearance gauges are characterized by the ability to measure small skimmers easily. Measurement can be made using only one leaf, but it is also possible to stack multiple leaves. However, it should be noted that stacking multiple leaves results in a slight loss of accuracy. Leaf sizes can be measured from a gap as small as 0.01mm. However, it should be noted that thin leaves tend to be crumpled and folded, making it impossible to obtain a correct measurement.

Two types of leaf shapes are specified. Type A has a constant leaf width and is stronger than Type B because only the tip of the leaf is rounded. Type A is usually used when there is sufficient space in the skimmer to be measured, while Type B gradually narrows the leaf width to about half the width at the tip. Type B is used when measuring narrower skimmers, but it is less strong than Type A, so care must be taken to avoid bending.

What Is a Square?

A square is a metal, L-shaped tool used to check the accuracy of right angles. There is a similar tool called a finger rectangle (also called a finger metal), but these are clearly distinguished. The square is thicker on the short side of the right angle and serves as the base. The base is placed in close contact with a flat surface to check for accuracy. A finger rectangle is a right-angle scale made of a thin metal plate on both sides. When checking right angles, a square is accurate when in contact with a reference surface, while a finger rectangle is not.

Uses of Squares

Squares are used to measure right angles and dimensions. They are used to check the squareness of metal, wood, and other materials when machining, sharpening, and charring. There are several types of squares. Squares with a base have a wide base on the short side of the right angle so that it can stand on its own. By placing the stand on the floor or base, it is possible to check if the part or furniture is right-angled, as well as to mark or mark the exact right-angled position. It can also be used to check if power tool blades are attached at right angles.

Features of Squares

The following is a description of the features of each typical type of square:

• Square with a base/full square/flat square
  All of them are L-shaped and are used to measure whether squares are right-angled or not. The short side of the pedestal/complete squares has a thick base, while the flat squares have the same thickness for both the short and long sides.
• Mighty square
  It has an L-shaped form and looks the same as squares with a base, but the edge of the long side where it connects to the long side of the base is angled at 45°. In addition to measuring right angles, it can also be used for marking and inking at a 45° angle.
• Trapezoidal square
  Trapezoidal shaped with four internal angles of 45°, 135°, 90°, and 90°, respectively. The short and long sides of the trapezoid are trapezoidal. Precise measurement, marking, and inking of 45° and 90° is possible.
• Free-form square
  This square consists of two boards connected by a screw. When the screw is loosened, the two plates can rotate to any position and can be stopped at any angle. It is used to set the angle by matching it to the angle on the drawing or to the angle of the actual object.
• Protractor
  A free type of hand square. The protractor consists of two plates with the center of rotation at the center of the protractor, so it can be used to measure, mark, and ink the desired angle.

What Is a Steam Trap?

A steam trap is a device that separates and discharges condensate (water droplets) generated within steam systems.

In factories, steam flows through pipes. When these pipes come into contact with the outside air, their surface temperature drops, causing the steam to cool and condense. If this condensate mixes with steam, it can violently collide at bends, such as elbows, leading to a condensate attack and potential damage to the piping. Erosion can also occur when condensate strikes the impellers of blowers or turbines. Installing steam traps helps avoid these issues.

Uses of Steam Traps

Steam traps are essential in piping systems where steam is utilized. By installing a steam trap, it is possible to collect condensate within the steam, thus preventing erosion and water hammering.

As steam cools and condenses, its volume significantly decreases, potentially causing a vacuum that draws condensate together, resulting in impact damage.

This can lead to severe damage to the piping and connected equipment, making the prevention capabilities of steam traps critical.

Principles of Steam Traps

Steam traps can be mechanical, thermodynamic, or thermostatic. Their operating principle varies by type.

1. Mechanical Type

The mechanical type operates simply. When condensate enters, it causes a float or bucket to rise, opening or closing the valve. This type is easy to maintain, and its operation can often be verified by sound. However, it requires regular maintenance to remove any dust accumulation on the valve to prevent continuous steam leakage.

2. Temperature Difference Type

The temperature difference type operates on the expansion and contraction caused by the temperature differential between steam and condensate. It is divided into bimetal and bellows types. The bimetal type relies on the differing expansion rates of two metals, while the bellows type uses a bellows mechanism for movement.

3. Thermodynamic Type

The thermodynamic type operates based on the pressure differences in the chamber between the primary and secondary sides. The valve opens as the high-temperature condensate expands the bimetal, allowing condensate discharge. Once the steam flows, the pressure drop causes the valve to close, repeating the cycle as needed.

Types of Steam Traps

1. Mechanical Type

Mechanical steam traps, utilizing the specific gravity difference between steam and condensate, are categorized into bucket and float types. The bucket type includes inverted bucket (I.B. type) and standard bucket types, while the float type includes designs with levers.

2. Temperature Difference Type

The thermostatic steam trap, or thermal differential type, operates on the temperature difference between steam and condensate. It includes bimetal and bellows types.

3. Thermodynamic Type

The thermodynamic steam trap utilizes the thermodynamic properties difference between steam and condensate, further classified into disc type and external air-cooled types.

How to Choose a Steam Trap

1. Mechanical Type

The mechanical type, offering no condensate retention and featuring an energy-saving design, includes the scale-resistant bucket type and the quick-warming, pressure-difference-resistant float type. However, the mechanical type may be susceptible to freezing and is relatively large. The float type is vulnerable to water hammer, and the bucket type’s installation direction may be restricted.

2. Temperature Difference Type

The thermostatic type is quiet and water hammer resistant. It allows for controlled condensate discharge temperature and features good low-noise air discharge performance. However, due to its lower-than-saturated steam temperature operation, condensate may accumulate, leading to delayed valve closing and steam loss. The bimetal parts are prone to corrosion and fatigue, affecting durability.

3. Thermodynamic Type

Compact and lightweight, the thermodynamic type is resistant to freezing and can be installed in any direction. However, it is sensitive to external temperatures, which may lead to dry hitting and potential condensate retention issues.

What Is a Stepper?

A stepper is a projection exposure system used in photolithography, the manufacturing process of semiconductors and liquid crystals.

As IC circuit patterns become finer and finer, it has become more difficult to create photomask patterns of actual size, and a stepper is an exposure system that uses the step-and-repeat method to expose mask patterns larger than the actual size in a reduced projection exposure. The step-and-repeat method means that when exposing semiconductor wafers or LCD substrates, the exposure area is divided into several sections, and once one section is exposed, the exposure is moved to the next section (step) and repeated (repeat).

A stepper is a type of exposure system that exposes the entire area to be exposed while stepping and repeating.

Uses of Steppers

Steppers are used in the manufacture of semiconductors and liquid crystals, especially for exposure using masks in the photolithography process.

There are two types of stepper systems: the step-and-repeat system, which exposes wafers sequentially while stepping them because the area that can be transferred at one time is small; and the scanner system, which exposes wafers by scanning the reticle synchronously at a speed corresponding to the projection magnification. The latter is distinguished from steppers and is sometimes treated as a scanner.

Principle of Steppers

Steppers uses a light source with a short wavelength to achieve high resolution in order to perform reduced projection exposures at high speed on large-diameter wafers and liquid crystals. The internal structure of steppers includes an exposure light source, projection lens, wafer stage, and wafer loader.

As the demand for large-scale integration of ICs increases, shorter wavelength exposure light sources are being used. In the 1990s, i-line light of 365nm was the principal light source. However, since then, shorter wavelengths such as Krf (wavelength: 248nm) and Arf (wavelength: 193nm) have been used.

A wafer stage is a stage that moves wafers at high speed in order to manufacture semiconductors such as ICs more quickly and with higher productivity. In addition to high-speed movement, high positioning accuracy is required for fine processing. The wafer loader is responsible for transporting wafers, such as removing wafers from the wafer stage and placing wafers on it.

Adhesion of foreign matter is a major enemy in IC manufacturing, and the sensitive wafers must be loaded and unloaded at high speed. Steppers are configured as shown above to perform sequential exposure while stepping wafers.

Other Information on Steppers

1. Immersion

Due to the high demand for precision, steppers and scanner systems, these days are equipped with large-scale mechanisms, and the price per unit is increasing. Therefore, as the wiring process nodes become finer, it is not desirable to suddenly make major changes to light sources and equipment mechanisms. There is a tendency to try to master the use of these devices by improving them over several generations.

One of the technologies to achieve this is “immersion.” Immersion refers to a method of increasing the exposure resolution of a light source by inserting a solution such as pure water between the resist on the wafer and the projection lens to shorten the wavelength of light compared to that in air. This is one of the technologies used in state-of-the-art photolithography processes. 

2. EUV Lithography

Extreme ultraviolet lithography (EUV lithography) is the core of the next-generation exposure technology for the most advanced process nodes at a few nm, which can be exposed at a wavelength of 13.5nm, and is called extreme ultraviolet lithography. Although the world’s leading semiconductor manufacturers are using this technology to compete in cutting-edge processes, as of 2022, only one company in the world has commercialized EUV lithography equipment.