Manufacture Integrated Circuits
available digital integrated circuits manufactured from silicon wafers. processing of silicon chips for IC or is relatively complicated.
The silicon used for the manufacture of chips is a purity of 99.9999999% of the order. Once synthesized, the silicon is melted in an inert atmosphere and crystallizes in the form of cylindrical bars of up to 10cm in diameter and 1 m long.
Each bar is cut into pellets 0.25 to 0.50 mm thick and the surfaces of the latter are polished to be shiny. depending on their size, you get hundreds of identical circuits (chips) on both surfaces by a process called planar, the same transistors used to mass produce ..
To manufacture a chip, the silicon wafers are processed first to make transistors. a silicon wafer itself is an insulator and does not conduct current. transistors are created by adding impurities such as phosphorus or arsenic in certain areas of the pill. connections are made through metal lines.
Every feature on the tablet form in the regions selected by spraying a protective chemical called light-sensitive photoresist, which forms a thin film on the surface of the tablet. the tablet is then bombarded with light, using a precise slide projector called boresight.
The aligner has a very small device called a mask, which prevents light falls on specific points of the tablet, when the light reaches a certain area of \u200b\u200bthe tablet eliminates the photoresist present in that area. this process is called photolithography.
Through a process of development, the chemical is deposited in regions exposed by the light and ignore concealed by the mask. these last areas still remain covered with "photoresist".
boresight accuracy determines how fine can be a Rasta. In the early 70's, it was difficult to make transistors smaller than 10 microns in size. Now the lower transistor sizes reach a speed of response of the device.
Then the pad is heated to high temperatures, this causes the unprocessed silicon surface becomes silicon oxide (SiO2). The SiO2 is spread over the surface of the wafer and form thereon a thin insulating film of a few microns thick.
This will get the first level of metallization of chips. To get a new metallization layer, the SiO2 is back with "photoresist" and exposed to boresight, repeating the same procedure used with silicon of the first level.
The different layers grow over each other forming a sandwich-like structure, with SiO2 as the bread and the metal or doped silicon as the sausage, most Integrated Circuits are not made with more than three layers of metallization.
materials integrated circuits
integrated circuits are made of silicon that serves as a base where they make transistors, diodes and resistors. Integrated circuits containing hundreds of these components distributed in an orderly way, this is achieved through a technique called photolithography which allows you to sort thousands of components on a small plate of silicon.
Classification according to Integrated Circuits structure
The classification of integrated circuits according to its structure can be based on the number of gates used to implement the specific function of the chip (called scale integration) as we know, the gates are basic building blocks of all digital circuits.
Integration scales are 4: SSI, MSI, LSI, VLSI, and then we will see each of them.
SSI Small Scale Integration .- Means (small scale integration) and includes the chips that contain less than 13 gates. Examples: gates and flip flops. SSI integrated circuits are manufactured using technologies TTL, CMOS and ECL. the first integrated circuits were SSI.
MSI Medium Scale Integration .- Mean (medium scale integration), and includes the chips that contain from 13 to 100 gates. Examples: encoders, registers, counters, multiplexers, encoders and multiplexers. MSI integrated circuits are manufactured using technologies TTL, CMOS and ECL.
.- LSI Large-Scale Integration means (high-scale integration) and includes chips containing 100 to 1000 gates. Examples: memory, arithmetic and logic units (ALU's), microprocessors of 8 and 16 bits. LSI Integrated Circuits are mainly manufactured using technologies I2L, nMOS and pMOS.
means VLSI .- Very Large Scale Integration (very high scale integration) and includes chips containing more than 1000 gates examples: micro-processor 32-bit micro-controllers, systems data acquisition. Integrated Circuits VSLI technologies are also made using TTL, CMOS and PMOS.
Luis Fernando Cantor Well
19135529
Ingenieria Electronica, Electronica De Estados sólidos
Seccion 2
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