IC Knowledge - Glossary

Glossary of Integrated Circuit Terminology - C

CAD - see Computer Aided Drafting.
Cantilever Loader - a piece of equipment that suspends boats of wafers in the air for insertion into and removal from furnaces. The cantilever is a long stiff bar held at one end and the wafer boats are placed on the cantilever. The cantilever is inserted into the furnace by a computer controlled - motorized mechanism that rides along a track in front of the furnace. The end of the cantilever that is held, is held outside of the furnace and the rest of the cantilever is suspended in such a way that the cantilever does not touch the sides of the furnace. Cantilever loading reduces rubbing against the furnace walls and dramatically reduces particle generation versus older wheeled sleds.
C-V Plot - see Capacitance Voltage Plot
Capacitance - the capability of a material or system of materials to store charge. The measure of capacitance is the farad.
Capacitance Voltage Plot - a technique used to characterize the amount of electrically active defects and mobile contaminants in a dielectric. Oxide fixed charge, oxide trapped charge, interface trapped charges, number of interface traps and mobile charge may all be measured. The technique may also be used to measure the profile of impurities in silicon.
Capital - items with a useful life of greater than one year and with a cost above some threshold value. Capital items are written off over a set period (Depreciation) related to the useful life of the item and accounting rules.
Carbon Dioxide - chemical formula CO₂, carbon dioxide is an asphyxiant with a TLV of 5,000ppm. Carbon dioxide is used in cleaning equipment and is a by product of photoresist stripping operations.
Carbon Monoxide - chemical formula CO, carbon monoxide is poisonous - odorless gas with a TLV of 35ppm. Carbon monoxide is a by product of photoresist stripping operations.
Carboxylic acid - Acids containing a carboxyl group, COOH.
Carcinogenic - cancer causing.
Carrier Gas - an inert gas used to carry some other substance into a process For example a carrier gas would be bubbled through a bubbler to carry vapor into a process. The carrier gas is inert to the extent that it does not take part in the process reaction.
Carriers - holes or electrons carrying electric current in a semiconductor.
Cassette - a Teflon or polypropylene wafer holder. Cassettes commonly hold up to 25 wafers.
Cathode - the negative terminal of an electrolytic cell. See also, anode.
Cavitation - the rapid formation and collapse of bubbles in a liquid.
CD - see Critical Dimensions.
CD Tool - a piece of equipment used to measure critical dimensions.
CD SEM - a scanning electron microscope used to measure critical dimensions.
Cells - individual devices or circuits that may be reused as blocks in designs.
CERDIP - Ceramic Dual In-Line Package, see also, DIP.
Channel - the region of a field effect transistor that conducts or blocks the flow of current when the device switches on and off respectively. See also, Metal Oxide Semiconductor.
Charged Coupled Device - a device that takes input light or electric charge and converts the intensity of the input into an output electronic signal. Charged coupled devices are designed as a group of pixels, where each pixel will trap electrons in proportion to the input stimuli. Each pixel may be read in sequence to determine the input stimuli level. Charged coupled devices are widely used in scientific instruments and digital cameras to capture images. Charged coupled devices are however more difficult to make than more common processes such as CMOS, although they do have better imaging performance. Due to easier fabrication, CMOS sensors are making inroads into traditional charged coupled device applications in the low-end, and CMOS sensor quality is rapidly improving as well.
Chemical Etching - the process of removing material-etching, through the use of chemical activity.
Chemical Mechanical Planarization (CMP) - a process whereby a chemical reaction increases the mechanical removal rate of a material. CMP is commonly used to polish off high spots on wafers or films deposited on wafers, flattening the film or wafer, referred to as planarization. The chemical reaction that increases the mechanical removal rate is commonly tailored to provide a higher removal rate of one material versus another material. The chemical action in CMP helps to achieve higher selectivity's of one material to another than a strictly mechanical process would provide.
Chemical Mechanical Polishing - an older terminology for Chemical Mechanical Planarization.
Chemical Vapor Deposition - a process whereby a film is deposited by reacting chemicals together in the gaseous or vapor phase to form a film. The gases or vapors utilized for CVD are compounds that contain the element to be deposited and that may be induced to react with a substrate or other gas(es) to deposit a film. The CVD reaction may be thermally activated, plasma induced, plasma enhanced CVD or activated by light in photon induced CVD. See also, Atmospheric Chemical Vapor Deposition, Low Pressure Chemical Vapor Deposition, Metal Organic Chemical Vapor Deposition, Photo Enhanced Chemical Vapor Deposition.
Chemically Amplified Photoresist - a type of photoresist where the exposure reaction initiates a chain reaction of chemical events. Chemically amplified photoresist are more sensitive than standard photoresist and are widely used for DUV exposure.
Chill Plate - a plate held at or below room temperature used to return wafers to room temperature following bakes.
Chip - a layman's term for a semiconductor die.
Chlorine - chemical formula Cl, chlorine is a corrosive - toxic gas with a TLV of 0.5ppm. Chlorine has a strong pungent odor and is irritating to lungs, skin and eyes. Chlorine is primarily used as an etch gas although it has seen some use as a furnace cleaning and oxidation additive.
Chrome - see Chromium.
Chromium - atomic symbol, Cr, chromium is the 24th element in the periodic table (atomic number 24) with an atomic weight of 52.00. A group VI metal, chromium has seen some use as a barrier metal in backside metal and under solder bumps. IBM in particular has made a large number of solder bumps with chromium barrier metal.
Circuit - a combination of electrical elements connected together to perform a specific function.
Circuit Layout - a schematic diagram converted to the pattern that will be transferred to a wafer by photolithography. Once a schematic of a circuit is complete and has been simulated, the schematic is converted to a circuit layout based on a set of design rules for the process being used. Certain elements of the layout may exist as cells that are connected together to make the circuit.
Cleanroom - a room combining the use of air filters and continuous air circulation to produce levels of air borne particles that are lower, and typically much lower than normal atmospheric dust levels. Outdoor atmospheric dust levels are on the order of 400,000 particles/ft³ >0.5µm in size. Cleanroom cleanliness levels generally are agreed to begin at 100,000 particles/ft³ and extend down to 0.01 particles/ft³ or less! See also, Cleanroom Class.
Cleanroom Class - a standard method for characterizing the cleanliness level of a cleanroom, originally developed by the U.S. government and released as the 209 standard. For example, a class 1 cleanroom has less than 1 particle and a class 100 cleanroom has less than 100 particles >0.5µm in size per ft³ of air respectively. Generally speaking a class 1000, class 100, class 10 and class 1, class 0.1 cleanroom will support production down to approximately, 4µms, 1.25µms, 0.7µms, 0.3µms and <0.1µms respectively.
Cluster Tool - a piece of equipment that utilizes a central robot to feed multiple process chambers. Cluster tools are commonly used to perform multiple process steps on a single piece of equipment and may improve process control and cycle time.
CMOS - see, Complimentary Metal Oxide Semiconductor.
CMP - see Chemical Mechanical Planarization.
Coater - a piece of semiconductor process equipment utilized to perform the coating process. Coaters typically provide an input and output elevator that can hold wafer cassettes, have a shuttle system to transport wafers from the input to the spin head, and transport wafers from the spin head to the output. Coaters may also include hotplates to bake wafers before or after coating and chill plates to return the wafer temperature to room temperature following baking.
Coating - the process of applying photoresist to a wafer, generally by dispensing a small amount of photoresist in the center of a wafer and then spinning the wafer at a high rate to spread and dry the photoresist.
Coherence Length - the wavelength of a light source divided by the bandwidth of light of the light source.
Coherent Light - coherence refers to the state or property of being together. Coherent light may be broken down into temporal coherence and spatial coherence.
Collector - the area of a bipolar transistor that collects carriers that have transitioned across the base region. See also, emitter.
Collimated Light - light that has parallel rays.
Collimated Sputtering - a sputtering process where the arrival of metal is at an angel normal to the wafer surface. The metal may be collimated by a thick honeycomb grid that blocks off angle metal atoms or by ionizing the metal atoms and attracting them towards the wafer. Collimated sputtering improves filling of high aspect ratio contacts. Colloidal Matter - particles with sizes of 1 to 200 nanometers in size.
Combustible - a material that will burn.
Common Cause Variation - the normal random variation in output for a process.
Complimentary Metal Oxide Semiconductor (CMOS) - a circuit that combines PMOS and NMOS devices in pairs. CMOS circuits only consume power when they are switching state. See also, NMOS and PMOS.
Compound - a substance made up of two or more elements.
Compound Semiconductor - a semiconductor made up of two or more elements, for example GaAs, InP, SiC are commonly used compound semiconductors.
Computer Aided Drafting - the design of products using a computer.
Concentration - the amount of a substance per unit area or volume. Concentration is commonly used to refer to the amount of dopant in a semiconductor as atoms per area or volume, or to refer to elements added to materials to change the material properties, etc. May be in weight or atomic percent or number per unit area or volume.
Condenser Lens - a lens or mirror used to concentrate light.
Conduction - the flow of electric current.
Conduction Band - a group of energy states that are empty at zero degrees kelvin and are available to support the movement of electrons that gain sufficient energy to jump from the valence band to empty levels in the conduction band.
Conductive - a material that is a conductor.
Conductor - a material which readily supports the flow of electric current. Conductors have overlapping valence and conduction bands or only partially filled bands. See also, Insulator, Semiconductor.
Contact Aligner - process equipment utilized to align masks to wafers and transfer patterns to the wafers by photolithography. In a contact aligner the wafer is actually brought into contact with the wafer during exposure. The first contact aligner became commercially available in 1963.
Contact Printing - the use of a contact aligner to expose a pattern onto a wafer using photolithography.
Contacts - openings in an Insulating film to allow contact to an underlying electronic device.
Contamination - any unwanted substance. Contamination of semiconductors may generally be categorized as metals, organic, oxide or particles.
Corrosive - a material which causes damage to skin, eyes or other parts on the body on contact
Coulomb - the quantity of electricity transferred by one ampere in one second. Equivalent to charge on 6.24 x 10¹⁸ elecrtons.
Critical Dimension - the width of a line or space that has been identified as critical to the device being fabricated operating properly. Critical dimensions are frequently measured on some or all wafers following any photolithography or etching process in which the dimensions are critical.
Critical Level - for a given minimum linewidth technology, the layers that have features at the minimum linewidth.
Cross Section - a view into the inside of a semiconductor made by cutting through the device. Cross sections allow the depth of diffusions into the semiconductor and the thickness of various films and their relationships to be examined.
Crossovers - areas in an integrated circuit where a conductor crosses over the top of another conductor or conductive region with the two conductors Insulated from each other.
Crossunders - areas in an integrated circuit where a conductor or conductive region crosses under another conductor with the two conductors insulated from each other.
Crystal Orientation - the orientation of the wafer surface to the crystal planes.
Crystal Planes - plane surfaces in a crystal formed by the periodic arrangement of the crystal atoms.
Crystalline - a material state where the atoms making up the material are arrayed in a consistent repeating pattern.
Cumulative Yield - the product of all of the individual yields in a process or process flow. For example, the wafer yield is frequently multiplied by the die yield to calculate an overall yield for wafer fabrication. Alternately the wafer yield, die yield, assembly yield and final test yield might be multiplied to get a cumulative yield for a product.
Current - the flow of electrons through a conductor measured in amperes.
Curvature of Field - in an ideal lens all points are focused in the same focal plane. Curvature of field results when the points of focus form a curved field.
Curve Tracer - a piece of equipment utilized to display the relationships between current and voltage for electronic devices.
CVD - see Chemical Vapor Deposition
Cycle Time - the actual time it takes to complete a process or sequence of processes.